src/src/expand.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2009 */
   6 /* See the file NOTICE for conditions of use and distribution. */
   7
   8
   9 /* Functions for handling string expansion. */
  10
  11
  12 #include "exim.h"
  13
  14 /* Recursively called function */
  15
  16 static uschar *expand_string_internal(uschar *, BOOL, uschar **, BOOL, BOOL);
  17
  18 #ifdef STAND_ALONE
  19 #ifndef SUPPORT_CRYPTEQ
  20 #define SUPPORT_CRYPTEQ
  21 #endif
  22 #endif
  23
  24 #ifdef LOOKUP_LDAP
  25 #include "lookups/ldap.h"
  26 #endif
  27
  28 #ifdef SUPPORT_CRYPTEQ
  29 #ifdef CRYPT_H
  30 #include <crypt.h>
  31 #endif
  32 #ifndef HAVE_CRYPT16
  33 extern char* crypt16(char*, char*);
  34 #endif
  35 #endif
  36
  37 /* The handling of crypt16() is a mess. I will record below the analysis of the
  38 mess that was sent to me. We decided, however, to make changing this very low
  39 priority, because in practice people are moving away from the crypt()
  40 algorithms nowadays, so it doesn't seem worth it.
  41
  42 <quote>
  43 There is an algorithm named "crypt16" in Ultrix and Tru64.  It crypts
  44 the first 8 characters of the password using a 20-round version of crypt
  45 (standard crypt does 25 rounds).  It then crypts the next 8 characters,
  46 or an empty block if the password is less than 9 characters, using a
  47 20-round version of crypt and the same salt as was used for the first
  48 block.  Charaters after the first 16 are ignored.  It always generates
  49 a 16-byte hash, which is expressed together with the salt as a string
  50 of 24 base 64 digits.  Here are some links to peruse:
  51
  52         http://cvs.pld.org.pl/pam/pamcrypt/crypt16.c?rev=1.2
  53         http://seclists.org/bugtraq/1999/Mar/0076.html
  54
  55 There's a different algorithm named "bigcrypt" in HP-UX, Digital Unix,
  56 and OSF/1.  This is the same as the standard crypt if given a password
  57 of 8 characters or less.  If given more, it first does the same as crypt
  58 using the first 8 characters, then crypts the next 8 (the 9th to 16th)
  59 using as salt the first two base 64 digits from the first hash block.
  60 If the password is more than 16 characters then it crypts the 17th to 24th
  61 characters using as salt the first two base 64 digits from the second hash
  62 block.  And so on: I've seen references to it cutting off the password at
  63 40 characters (5 blocks), 80 (10 blocks), or 128 (16 blocks).  Some links:
  64
  65         http://cvs.pld.org.pl/pam/pamcrypt/bigcrypt.c?rev=1.2
  66         http://seclists.org/bugtraq/1999/Mar/0109.html
  67         http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/HTML/AA-Q0R2D-
  68              TET1_html/sec.c222.html#no_id_208
  69
  70 Exim has something it calls "crypt16".  It will either use a native
  71 crypt16 or its own implementation.  A native crypt16 will presumably
  72 be the one that I called "crypt16" above.  The internal "crypt16"
  73 function, however, is a two-block-maximum implementation of what I called
  74 "bigcrypt".  The documentation matches the internal code.
  75
  76 I suspect that whoever did the "crypt16" stuff for Exim didn't realise
  77 that crypt16 and bigcrypt were different things.
  78
  79 Exim uses the LDAP-style scheme identifier "{crypt16}" to refer
  80 to whatever it is using under that name.  This unfortunately sets a
  81 precedent for using "{crypt16}" to identify two incompatible algorithms
  82 whose output can't be distinguished.  With "{crypt16}" thus rendered
  83 ambiguous, I suggest you deprecate it and invent two new identifiers
  84 for the two algorithms.
  85
  86 Both crypt16 and bigcrypt are very poor algorithms, btw.  Hashing parts
  87 of the password separately means they can be cracked separately, so
  88 the double-length hash only doubles the cracking effort instead of
  89 squaring it.  I recommend salted SHA-1 ({SSHA}), or the Blowfish-based
  90 bcrypt ({CRYPT}$2a$).
  91 </quote>
  92 */
  93
  94
  95
  96
  97 /*************************************************
  98 *            Local statics and tables            *
  99 *************************************************/
 100
 101 /* Table of item names, and corresponding switch numbers. The names must be in
 102 alphabetical order. */
 103
 104 static uschar *item_table[] = {
 105   US"dlfunc",
 106   US"extract",
 107   US"filter",
 108   US"hash",
 109   US"hmac",
 110   US"if",
 111   US"length",
 112   US"lookup",
 113   US"map",
 114   US"nhash",
 115   US"perl",
 116   US"prvs",
 117   US"prvscheck",
 118   US"readfile",
 119   US"readsocket",
 120   US"reduce",
 121   US"run",
 122   US"sg",
 123   US"substr",
 124   US"tr" };
 125
 126 enum {
 127   EITEM_DLFUNC,
 128   EITEM_EXTRACT,
 129   EITEM_FILTER,
 130   EITEM_HASH,
 131   EITEM_HMAC,
 132   EITEM_IF,
 133   EITEM_LENGTH,
 134   EITEM_LOOKUP,
 135   EITEM_MAP,
 136   EITEM_NHASH,
 137   EITEM_PERL,
 138   EITEM_PRVS,
 139   EITEM_PRVSCHECK,
 140   EITEM_READFILE,
 141   EITEM_READSOCK,
 142   EITEM_REDUCE,
 143   EITEM_RUN,
 144   EITEM_SG,
 145   EITEM_SUBSTR,
 146   EITEM_TR };
 147
 148 /* Tables of operator names, and corresponding switch numbers. The names must be
 149 in alphabetical order. There are two tables, because underscore is used in some
 150 cases to introduce arguments, whereas for other it is part of the name. This is
 151 an historical mis-design. */
 152
 153 static uschar *op_table_underscore[] = {
 154   US"from_utf8",
 155   US"local_part",
 156   US"quote_local_part",
 157   US"reverse_ip",
 158   US"time_eval",
 159   US"time_interval"};
 160
 161 enum {
 162   EOP_FROM_UTF8,
 163   EOP_LOCAL_PART,
 164   EOP_QUOTE_LOCAL_PART,
 165   EOP_REVERSE_IP,
 166   EOP_TIME_EVAL,
 167   EOP_TIME_INTERVAL };
 168
 169 static uschar *op_table_main[] = {
 170   US"address",
 171   US"addresses",
 172   US"base62",
 173   US"base62d",
 174   US"domain",
 175   US"escape",
 176   US"eval",
 177   US"eval10",
 178   US"expand",
 179   US"h",
 180   US"hash",
 181   US"hex2b64",
 182   US"l",
 183   US"lc",
 184   US"length",
 185   US"mask",
 186   US"md5",
 187   US"nh",
 188   US"nhash",
 189   US"quote",
 190   US"randint",
 191   US"rfc2047",
 192   US"rfc2047d",
 193   US"rxquote",
 194   US"s",
 195   US"sha1",
 196   US"stat",
 197   US"str2b64",
 198   US"strlen",
 199   US"substr",
 200   US"uc" };
 201
 202 enum {
 203   EOP_ADDRESS =  sizeof(op_table_underscore)/sizeof(uschar *),
 204   EOP_ADDRESSES,
 205   EOP_BASE62,
 206   EOP_BASE62D,
 207   EOP_DOMAIN,
 208   EOP_ESCAPE,
 209   EOP_EVAL,
 210   EOP_EVAL10,
 211   EOP_EXPAND,
 212   EOP_H,
 213   EOP_HASH,
 214   EOP_HEX2B64,
 215   EOP_L,
 216   EOP_LC,
 217   EOP_LENGTH,
 218   EOP_MASK,
 219   EOP_MD5,
 220   EOP_NH,
 221   EOP_NHASH,
 222   EOP_QUOTE,
 223   EOP_RANDINT,
 224   EOP_RFC2047,
 225   EOP_RFC2047D,
 226   EOP_RXQUOTE,
 227   EOP_S,
 228   EOP_SHA1,
 229   EOP_STAT,
 230   EOP_STR2B64,
 231   EOP_STRLEN,
 232   EOP_SUBSTR,
 233   EOP_UC };
 234
 235
 236 /* Table of condition names, and corresponding switch numbers. The names must
 237 be in alphabetical order. */
 238
 239 static uschar *cond_table[] = {
 240   US"<",
 241   US"<=",
 242   US"=",
 243   US"==",     /* Backward compatibility */
 244   US">",
 245   US">=",
 246   US"and",
 247   US"bool",
 248   US"bool_lax",
 249   US"crypteq",
 250   US"def",
 251   US"eq",
 252   US"eqi",
 253   US"exists",
 254   US"first_delivery",
 255   US"forall",
 256   US"forany",
 257   US"ge",
 258   US"gei",
 259   US"gt",
 260   US"gti",
 261   US"inlist",
 262   US"inlisti",
 263   US"isip",
 264   US"isip4",
 265   US"isip6",
 266   US"ldapauth",
 267   US"le",
 268   US"lei",
 269   US"lt",
 270   US"lti",
 271   US"match",
 272   US"match_address",
 273   US"match_domain",
 274   US"match_ip",
 275   US"match_local_part",
 276   US"or",
 277   US"pam",
 278   US"pwcheck",
 279   US"queue_running",
 280   US"radius",
 281   US"saslauthd"
 282 };
 283
 284 enum {
 285   ECOND_NUM_L,
 286   ECOND_NUM_LE,
 287   ECOND_NUM_E,
 288   ECOND_NUM_EE,
 289   ECOND_NUM_G,
 290   ECOND_NUM_GE,
 291   ECOND_AND,
 292   ECOND_BOOL,
 293   ECOND_BOOL_LAX,
 294   ECOND_CRYPTEQ,
 295   ECOND_DEF,
 296   ECOND_STR_EQ,
 297   ECOND_STR_EQI,
 298   ECOND_EXISTS,
 299   ECOND_FIRST_DELIVERY,
 300   ECOND_FORALL,
 301   ECOND_FORANY,
 302   ECOND_STR_GE,
 303   ECOND_STR_GEI,
 304   ECOND_STR_GT,
 305   ECOND_STR_GTI,
 306   ECOND_INLIST,
 307   ECOND_INLISTI,
 308   ECOND_ISIP,
 309   ECOND_ISIP4,
 310   ECOND_ISIP6,
 311   ECOND_LDAPAUTH,
 312   ECOND_STR_LE,
 313   ECOND_STR_LEI,
 314   ECOND_STR_LT,
 315   ECOND_STR_LTI,
 316   ECOND_MATCH,
 317   ECOND_MATCH_ADDRESS,
 318   ECOND_MATCH_DOMAIN,
 319   ECOND_MATCH_IP,
 320   ECOND_MATCH_LOCAL_PART,
 321   ECOND_OR,
 322   ECOND_PAM,
 323   ECOND_PWCHECK,
 324   ECOND_QUEUE_RUNNING,
 325   ECOND_RADIUS,
 326   ECOND_SASLAUTHD
 327 };
 328
 329
 330 /* Type for main variable table */
 331
 332 typedef struct {
 333   const char *name;
 334   int         type;
 335   void       *value;
 336 } var_entry;
 337
 338 /* Type for entries pointing to address/length pairs. Not currently
 339 in use. */
 340
 341 typedef struct {
 342   uschar **address;
 343   int  *length;
 344 } alblock;
 345
 346 /* Types of table entry */
 347
 348 enum {
 349   vtype_int,            /* value is address of int */
 350   vtype_filter_int,     /* ditto, but recognized only when filtering */
 351   vtype_ino,            /* value is address of ino_t (not always an int) */
 352   vtype_uid,            /* value is address of uid_t (not always an int) */
 353   vtype_gid,            /* value is address of gid_t (not always an int) */
 354   vtype_stringptr,      /* value is address of pointer to string */
 355   vtype_msgbody,        /* as stringptr, but read when first required */
 356   vtype_msgbody_end,    /* ditto, the end of the message */
 357   vtype_msgheaders,     /* the message's headers, processed */
 358   vtype_msgheaders_raw, /* the message's headers, unprocessed */
 359   vtype_localpart,      /* extract local part from string */
 360   vtype_domain,         /* extract domain from string */
 361   vtype_recipients,     /* extract recipients from recipients list */
 362                         /* (available only in system filters, ACLs, and */
 363                         /* local_scan()) */
 364   vtype_todbsdin,       /* value not used; generate BSD inbox tod */
 365   vtype_tode,           /* value not used; generate tod in epoch format */
 366   vtype_todf,           /* value not used; generate full tod */
 367   vtype_todl,           /* value not used; generate log tod */
 368   vtype_todlf,          /* value not used; generate log file datestamp tod */
 369   vtype_todzone,        /* value not used; generate time zone only */
 370   vtype_todzulu,        /* value not used; generate zulu tod */
 371   vtype_reply,          /* value not used; get reply from headers */
 372   vtype_pid,            /* value not used; result is pid */
 373   vtype_host_lookup,    /* value not used; get host name */
 374   vtype_load_avg,       /* value not used; result is int from os_getloadavg */
 375   vtype_pspace,         /* partition space; value is T/F for spool/log */
 376   vtype_pinodes         /* partition inodes; value is T/F for spool/log */
 377   #ifndef DISABLE_DKIM
 378   ,vtype_dkim           /* Lookup of value in DKIM signature */
 379   #endif
 380   };
 381
 382 /* This table must be kept in alphabetical order. */
 383
 384 static var_entry var_table[] = {
 385   /* WARNING: Do not invent variables whose names start acl_c or acl_m because
 386      they will be confused with user-creatable ACL variables. */
 387   { "acl_verify_message",  vtype_stringptr,   &acl_verify_message },
 388   { "address_data",        vtype_stringptr,   &deliver_address_data },
 389   { "address_file",        vtype_stringptr,   &address_file },
 390   { "address_pipe",        vtype_stringptr,   &address_pipe },
 391   { "authenticated_id",    vtype_stringptr,   &authenticated_id },
 392   { "authenticated_sender",vtype_stringptr,   &authenticated_sender },
 393   { "authentication_failed",vtype_int,        &authentication_failed },
 394 #ifdef WITH_CONTENT_SCAN
 395   { "av_failed",           vtype_int,         &av_failed },
 396 #endif
 397 #ifdef EXPERIMENTAL_BRIGHTMAIL
 398   { "bmi_alt_location",    vtype_stringptr,   &bmi_alt_location },
 399   { "bmi_base64_tracker_verdict", vtype_stringptr, &bmi_base64_tracker_verdict },
 400   { "bmi_base64_verdict",  vtype_stringptr,   &bmi_base64_verdict },
 401   { "bmi_deliver",         vtype_int,         &bmi_deliver },
 402 #endif
 403   { "body_linecount",      vtype_int,         &body_linecount },
 404   { "body_zerocount",      vtype_int,         &body_zerocount },
 405   { "bounce_recipient",    vtype_stringptr,   &bounce_recipient },
 406   { "bounce_return_size_limit", vtype_int,    &bounce_return_size_limit },
 407   { "caller_gid",          vtype_gid,         &real_gid },
 408   { "caller_uid",          vtype_uid,         &real_uid },
 409   { "compile_date",        vtype_stringptr,   &version_date },
 410   { "compile_number",      vtype_stringptr,   &version_cnumber },
 411   { "csa_status",          vtype_stringptr,   &csa_status },
 412 #ifdef EXPERIMENTAL_DCC
 413   { "dcc_header",          vtype_stringptr,   &dcc_header },
 414   { "dcc_result",          vtype_stringptr,   &dcc_result },
 415 #endif
 416 #ifdef WITH_OLD_DEMIME
 417   { "demime_errorlevel",   vtype_int,         &demime_errorlevel },
 418   { "demime_reason",       vtype_stringptr,   &demime_reason },
 419 #endif
 420 #ifndef DISABLE_DKIM
 421   { "dkim_algo",           vtype_dkim,        (void *)DKIM_ALGO },
 422   { "dkim_bodylength",     vtype_dkim,        (void *)DKIM_BODYLENGTH },
 423   { "dkim_canon_body",     vtype_dkim,        (void *)DKIM_CANON_BODY },
 424   { "dkim_canon_headers",  vtype_dkim,        (void *)DKIM_CANON_HEADERS },
 425   { "dkim_copiedheaders",  vtype_dkim,        (void *)DKIM_COPIEDHEADERS },
 426   { "dkim_created",        vtype_dkim,        (void *)DKIM_CREATED },
 427   { "dkim_cur_signer",     vtype_stringptr,   &dkim_cur_signer },
 428   { "dkim_domain",         vtype_stringptr,   &dkim_signing_domain },
 429   { "dkim_expires",        vtype_dkim,        (void *)DKIM_EXPIRES },
 430   { "dkim_headernames",    vtype_dkim,        (void *)DKIM_HEADERNAMES },
 431   { "dkim_identity",       vtype_dkim,        (void *)DKIM_IDENTITY },
 432   { "dkim_key_granularity",vtype_dkim,        (void *)DKIM_KEY_GRANULARITY },
 433   { "dkim_key_nosubdomains",vtype_dkim,       (void *)DKIM_NOSUBDOMAINS },
 434   { "dkim_key_notes",      vtype_dkim,        (void *)DKIM_KEY_NOTES },
 435   { "dkim_key_srvtype",    vtype_dkim,        (void *)DKIM_KEY_SRVTYPE },
 436   { "dkim_key_testing",    vtype_dkim,        (void *)DKIM_KEY_TESTING },
 437   { "dkim_selector",       vtype_stringptr,   &dkim_signing_selector },
 438   { "dkim_signers",        vtype_stringptr,   &dkim_signers },
 439   { "dkim_verify_reason",  vtype_dkim,        (void *)DKIM_VERIFY_REASON },
 440   { "dkim_verify_status",  vtype_dkim,        (void *)DKIM_VERIFY_STATUS},
 441 #endif
 442   { "dnslist_domain",      vtype_stringptr,   &dnslist_domain },
 443   { "dnslist_matched",     vtype_stringptr,   &dnslist_matched },
 444   { "dnslist_text",        vtype_stringptr,   &dnslist_text },
 445   { "dnslist_value",       vtype_stringptr,   &dnslist_value },
 446   { "domain",              vtype_stringptr,   &deliver_domain },
 447   { "domain_data",         vtype_stringptr,   &deliver_domain_data },
 448   { "exim_gid",            vtype_gid,         &exim_gid },
 449   { "exim_path",           vtype_stringptr,   &exim_path },
 450   { "exim_uid",            vtype_uid,         &exim_uid },
 451 #ifdef WITH_OLD_DEMIME
 452   { "found_extension",     vtype_stringptr,   &found_extension },
 453 #endif
 454   { "home",                vtype_stringptr,   &deliver_home },
 455   { "host",                vtype_stringptr,   &deliver_host },
 456   { "host_address",        vtype_stringptr,   &deliver_host_address },
 457   { "host_data",           vtype_stringptr,   &host_data },
 458   { "host_lookup_deferred",vtype_int,         &host_lookup_deferred },
 459   { "host_lookup_failed",  vtype_int,         &host_lookup_failed },
 460   { "inode",               vtype_ino,         &deliver_inode },
 461   { "interface_address",   vtype_stringptr,   &interface_address },
 462   { "interface_port",      vtype_int,         &interface_port },
 463   { "item",                vtype_stringptr,   &iterate_item },
 464   #ifdef LOOKUP_LDAP
 465   { "ldap_dn",             vtype_stringptr,   &eldap_dn },
 466   #endif
 467   { "load_average",        vtype_load_avg,    NULL },
 468   { "local_part",          vtype_stringptr,   &deliver_localpart },
 469   { "local_part_data",     vtype_stringptr,   &deliver_localpart_data },
 470   { "local_part_prefix",   vtype_stringptr,   &deliver_localpart_prefix },
 471   { "local_part_suffix",   vtype_stringptr,   &deliver_localpart_suffix },
 472   { "local_scan_data",     vtype_stringptr,   &local_scan_data },
 473   { "local_user_gid",      vtype_gid,         &local_user_gid },
 474   { "local_user_uid",      vtype_uid,         &local_user_uid },
 475   { "localhost_number",    vtype_int,         &host_number },
 476   { "log_inodes",          vtype_pinodes,     (void *)FALSE },
 477   { "log_space",           vtype_pspace,      (void *)FALSE },
 478   { "mailstore_basename",  vtype_stringptr,   &mailstore_basename },
 479 #ifdef WITH_CONTENT_SCAN
 480   { "malware_name",        vtype_stringptr,   &malware_name },
 481 #endif
 482   { "max_received_linelength", vtype_int,     &max_received_linelength },
 483   { "message_age",         vtype_int,         &message_age },
 484   { "message_body",        vtype_msgbody,     &message_body },
 485   { "message_body_end",    vtype_msgbody_end, &message_body_end },
 486   { "message_body_size",   vtype_int,         &message_body_size },
 487   { "message_exim_id",     vtype_stringptr,   &message_id },
 488   { "message_headers",     vtype_msgheaders,  NULL },
 489   { "message_headers_raw", vtype_msgheaders_raw, NULL },
 490   { "message_id",          vtype_stringptr,   &message_id },
 491   { "message_linecount",   vtype_int,         &message_linecount },
 492   { "message_size",        vtype_int,         &message_size },
 493 #ifdef WITH_CONTENT_SCAN
 494   { "mime_anomaly_level",  vtype_int,         &mime_anomaly_level },
 495   { "mime_anomaly_text",   vtype_stringptr,   &mime_anomaly_text },
 496   { "mime_boundary",       vtype_stringptr,   &mime_boundary },
 497   { "mime_charset",        vtype_stringptr,   &mime_charset },
 498   { "mime_content_description", vtype_stringptr, &mime_content_description },
 499   { "mime_content_disposition", vtype_stringptr, &mime_content_disposition },
 500   { "mime_content_id",     vtype_stringptr,   &mime_content_id },
 501   { "mime_content_size",   vtype_int,         &mime_content_size },
 502   { "mime_content_transfer_encoding",vtype_stringptr, &mime_content_transfer_encoding },
 503   { "mime_content_type",   vtype_stringptr,   &mime_content_type },
 504   { "mime_decoded_filename", vtype_stringptr, &mime_decoded_filename },
 505   { "mime_filename",       vtype_stringptr,   &mime_filename },
 506   { "mime_is_coverletter", vtype_int,         &mime_is_coverletter },
 507   { "mime_is_multipart",   vtype_int,         &mime_is_multipart },
 508   { "mime_is_rfc822",      vtype_int,         &mime_is_rfc822 },
 509   { "mime_part_count",     vtype_int,         &mime_part_count },
 510 #endif
 511   { "n0",                  vtype_filter_int,  &filter_n[0] },
 512   { "n1",                  vtype_filter_int,  &filter_n[1] },
 513   { "n2",                  vtype_filter_int,  &filter_n[2] },
 514   { "n3",                  vtype_filter_int,  &filter_n[3] },
 515   { "n4",                  vtype_filter_int,  &filter_n[4] },
 516   { "n5",                  vtype_filter_int,  &filter_n[5] },
 517   { "n6",                  vtype_filter_int,  &filter_n[6] },
 518   { "n7",                  vtype_filter_int,  &filter_n[7] },
 519   { "n8",                  vtype_filter_int,  &filter_n[8] },
 520   { "n9",                  vtype_filter_int,  &filter_n[9] },
 521   { "original_domain",     vtype_stringptr,   &deliver_domain_orig },
 522   { "original_local_part", vtype_stringptr,   &deliver_localpart_orig },
 523   { "originator_gid",      vtype_gid,         &originator_gid },
 524   { "originator_uid",      vtype_uid,         &originator_uid },
 525   { "parent_domain",       vtype_stringptr,   &deliver_domain_parent },
 526   { "parent_local_part",   vtype_stringptr,   &deliver_localpart_parent },
 527   { "pid",                 vtype_pid,         NULL },
 528   { "primary_hostname",    vtype_stringptr,   &primary_hostname },
 529   { "prvscheck_address",   vtype_stringptr,   &prvscheck_address },
 530   { "prvscheck_keynum",    vtype_stringptr,   &prvscheck_keynum },
 531   { "prvscheck_result",    vtype_stringptr,   &prvscheck_result },
 532   { "qualify_domain",      vtype_stringptr,   &qualify_domain_sender },
 533   { "qualify_recipient",   vtype_stringptr,   &qualify_domain_recipient },
 534   { "rcpt_count",          vtype_int,         &rcpt_count },
 535   { "rcpt_defer_count",    vtype_int,         &rcpt_defer_count },
 536   { "rcpt_fail_count",     vtype_int,         &rcpt_fail_count },
 537   { "received_count",      vtype_int,         &received_count },
 538   { "received_for",        vtype_stringptr,   &received_for },
 539   { "received_ip_address", vtype_stringptr,   &interface_address },
 540   { "received_port",       vtype_int,         &interface_port },
 541   { "received_protocol",   vtype_stringptr,   &received_protocol },
 542   { "received_time",       vtype_int,         &received_time },
 543   { "recipient_data",      vtype_stringptr,   &recipient_data },
 544   { "recipient_verify_failure",vtype_stringptr,&recipient_verify_failure },
 545   { "recipients",          vtype_recipients,  NULL },
 546   { "recipients_count",    vtype_int,         &recipients_count },
 547 #ifdef WITH_CONTENT_SCAN
 548   { "regex_match_string",  vtype_stringptr,   &regex_match_string },
 549 #endif
 550   { "reply_address",       vtype_reply,       NULL },
 551   { "return_path",         vtype_stringptr,   &return_path },
 552   { "return_size_limit",   vtype_int,         &bounce_return_size_limit },
 553   { "runrc",               vtype_int,         &runrc },
 554   { "self_hostname",       vtype_stringptr,   &self_hostname },
 555   { "sender_address",      vtype_stringptr,   &sender_address },
 556   { "sender_address_data", vtype_stringptr,   &sender_address_data },
 557   { "sender_address_domain", vtype_domain,    &sender_address },
 558   { "sender_address_local_part", vtype_localpart, &sender_address },
 559   { "sender_data",         vtype_stringptr,   &sender_data },
 560   { "sender_fullhost",     vtype_stringptr,   &sender_fullhost },
 561   { "sender_helo_name",    vtype_stringptr,   &sender_helo_name },
 562   { "sender_host_address", vtype_stringptr,   &sender_host_address },
 563   { "sender_host_authenticated",vtype_stringptr, &sender_host_authenticated },
 564   { "sender_host_name",    vtype_host_lookup, NULL },
 565   { "sender_host_port",    vtype_int,         &sender_host_port },
 566   { "sender_ident",        vtype_stringptr,   &sender_ident },
 567   { "sender_rate",         vtype_stringptr,   &sender_rate },
 568   { "sender_rate_limit",   vtype_stringptr,   &sender_rate_limit },
 569   { "sender_rate_period",  vtype_stringptr,   &sender_rate_period },
 570   { "sender_rcvhost",      vtype_stringptr,   &sender_rcvhost },
 571   { "sender_verify_failure",vtype_stringptr,  &sender_verify_failure },
 572   { "sending_ip_address",  vtype_stringptr,   &sending_ip_address },
 573   { "sending_port",        vtype_int,         &sending_port },
 574   { "smtp_active_hostname", vtype_stringptr,  &smtp_active_hostname },
 575   { "smtp_command",        vtype_stringptr,   &smtp_cmd_buffer },
 576   { "smtp_command_argument", vtype_stringptr, &smtp_cmd_argument },
 577   { "smtp_count_at_connection_start", vtype_int, &smtp_accept_count },
 578   { "smtp_notquit_reason", vtype_stringptr,   &smtp_notquit_reason },
 579   { "sn0",                 vtype_filter_int,  &filter_sn[0] },
 580   { "sn1",                 vtype_filter_int,  &filter_sn[1] },
 581   { "sn2",                 vtype_filter_int,  &filter_sn[2] },
 582   { "sn3",                 vtype_filter_int,  &filter_sn[3] },
 583   { "sn4",                 vtype_filter_int,  &filter_sn[4] },
 584   { "sn5",                 vtype_filter_int,  &filter_sn[5] },
 585   { "sn6",                 vtype_filter_int,  &filter_sn[6] },
 586   { "sn7",                 vtype_filter_int,  &filter_sn[7] },
 587   { "sn8",                 vtype_filter_int,  &filter_sn[8] },
 588   { "sn9",                 vtype_filter_int,  &filter_sn[9] },
 589 #ifdef WITH_CONTENT_SCAN
 590   { "spam_bar",            vtype_stringptr,   &spam_bar },
 591   { "spam_report",         vtype_stringptr,   &spam_report },
 592   { "spam_score",          vtype_stringptr,   &spam_score },
 593   { "spam_score_int",      vtype_stringptr,   &spam_score_int },
 594 #endif
 595 #ifdef EXPERIMENTAL_SPF
 596   { "spf_guess",           vtype_stringptr,   &spf_guess },
 597   { "spf_header_comment",  vtype_stringptr,   &spf_header_comment },
 598   { "spf_received",        vtype_stringptr,   &spf_received },
 599   { "spf_result",          vtype_stringptr,   &spf_result },
 600   { "spf_smtp_comment",    vtype_stringptr,   &spf_smtp_comment },
 601 #endif
 602   { "spool_directory",     vtype_stringptr,   &spool_directory },
 603   { "spool_inodes",        vtype_pinodes,     (void *)TRUE },
 604   { "spool_space",         vtype_pspace,      (void *)TRUE },
 605 #ifdef EXPERIMENTAL_SRS
 606   { "srs_db_address",      vtype_stringptr,   &srs_db_address },
 607   { "srs_db_key",          vtype_stringptr,   &srs_db_key },
 608   { "srs_orig_recipient",  vtype_stringptr,   &srs_orig_recipient },
 609   { "srs_orig_sender",     vtype_stringptr,   &srs_orig_sender },
 610   { "srs_recipient",       vtype_stringptr,   &srs_recipient },
 611   { "srs_status",          vtype_stringptr,   &srs_status },
 612 #endif
 613   { "thisaddress",         vtype_stringptr,   &filter_thisaddress },
 614   { "tls_certificate_verified", vtype_int,    &tls_certificate_verified },
 615   { "tls_cipher",          vtype_stringptr,   &tls_cipher },
 616   { "tls_peerdn",          vtype_stringptr,   &tls_peerdn },
 617   { "tod_bsdinbox",        vtype_todbsdin,    NULL },
 618   { "tod_epoch",           vtype_tode,        NULL },
 619   { "tod_full",            vtype_todf,        NULL },
 620   { "tod_log",             vtype_todl,        NULL },
 621   { "tod_logfile",         vtype_todlf,       NULL },
 622   { "tod_zone",            vtype_todzone,     NULL },
 623   { "tod_zulu",            vtype_todzulu,     NULL },
 624   { "value",               vtype_stringptr,   &lookup_value },
 625   { "version_number",      vtype_stringptr,   &version_string },
 626   { "warn_message_delay",  vtype_stringptr,   &warnmsg_delay },
 627   { "warn_message_recipient",vtype_stringptr, &warnmsg_recipients },
 628   { "warn_message_recipients",vtype_stringptr,&warnmsg_recipients },
 629   { "warnmsg_delay",       vtype_stringptr,   &warnmsg_delay },
 630   { "warnmsg_recipient",   vtype_stringptr,   &warnmsg_recipients },
 631   { "warnmsg_recipients",  vtype_stringptr,   &warnmsg_recipients }
 632 };
 633
 634 static int var_table_size = sizeof(var_table)/sizeof(var_entry);
 635 static uschar var_buffer[256];
 636 static BOOL malformed_header;
 637
 638 /* For textual hashes */
 639
 640 static const char *hashcodes = "abcdefghijklmnopqrtsuvwxyz"
 641                                "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 642                                "0123456789";
 643
 644 enum { HMAC_MD5, HMAC_SHA1 };
 645
 646 /* For numeric hashes */
 647
 648 static unsigned int prime[] = {
 649   2,   3,   5,   7,  11,  13,  17,  19,  23,  29,
 650  31,  37,  41,  43,  47,  53,  59,  61,  67,  71,
 651  73,  79,  83,  89,  97, 101, 103, 107, 109, 113};
 652
 653 /* For printing modes in symbolic form */
 654
 655 static uschar *mtable_normal[] =
 656   { US"---", US"--x", US"-w-", US"-wx", US"r--", US"r-x", US"rw-", US"rwx" };
 657
 658 static uschar *mtable_setid[] =
 659   { US"--S", US"--s", US"-wS", US"-ws", US"r-S", US"r-s", US"rwS", US"rws" };
 660
 661 static uschar *mtable_sticky[] =
 662   { US"--T", US"--t", US"-wT", US"-wt", US"r-T", US"r-t", US"rwT", US"rwt" };
 663
 664
 665
 666 /*************************************************
 667 *           Tables for UTF-8 support             *
 668 *************************************************/
 669
 670 /* Table of the number of extra characters, indexed by the first character
 671 masked with 0x3f. The highest number for a valid UTF-8 character is in fact
 672 0x3d. */
 673
 674 static uschar utf8_table1[] = {
 675   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 676   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 677   2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
 678   3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5 };
 679
 680 /* These are the masks for the data bits in the first byte of a character,
 681 indexed by the number of additional bytes. */
 682
 683 static int utf8_table2[] = { 0xff, 0x1f, 0x0f, 0x07, 0x03, 0x01};
 684
 685 /* Get the next UTF-8 character, advancing the pointer. */
 686
 687 #define GETUTF8INC(c, ptr) \
 688   c = *ptr++; \
 689   if ((c & 0xc0) == 0xc0) \
 690     { \
 691     int a = utf8_table1[c & 0x3f];  /* Number of additional bytes */ \
 692     int s = 6*a; \
 693     c = (c & utf8_table2[a]) << s; \
 694     while (a-- > 0) \
 695       { \
 696       s -= 6; \
 697       c |= (*ptr++ & 0x3f) << s; \
 698       } \
 699     }
 700
 701
 702 /*************************************************
 703 *           Binary chop search on a table        *
 704 *************************************************/
 705
 706 /* This is used for matching expansion items and operators.
 707
 708 Arguments:
 709   name        the name that is being sought
 710   table       the table to search
 711   table_size  the number of items in the table
 712
 713 Returns:      the offset in the table, or -1
 714 */
 715
 716 static int
 717 chop_match(uschar *name, uschar **table, int table_size)
 718 {
 719 uschar **bot = table;
 720 uschar **top = table + table_size;
 721
 722 while (top > bot)
 723   {
 724   uschar **mid = bot + (top - bot)/2;
 725   int c = Ustrcmp(name, *mid);
 726   if (c == 0) return mid - table;
 727   if (c > 0) bot = mid + 1; else top = mid;
 728   }
 729
 730 return -1;
 731 }
 732
 733
 734
 735 /*************************************************
 736 *          Check a condition string              *
 737 *************************************************/
 738
 739 /* This function is called to expand a string, and test the result for a "true"
 740 or "false" value. Failure of the expansion yields FALSE; logged unless it was a
 741 forced fail or lookup defer. All store used by the function can be released on
 742 exit.
 743
 744 The actual false-value tests should be replicated for ECOND_BOOL_LAX.
 745
 746 Arguments:
 747   condition     the condition string
 748   m1            text to be incorporated in panic error
 749   m2            ditto
 750
 751 Returns:        TRUE if condition is met, FALSE if not
 752 */
 753
 754 BOOL
 755 expand_check_condition(uschar *condition, uschar *m1, uschar *m2)
 756 {
 757 int rc;
 758 void *reset_point = store_get(0);
 759 uschar *ss = expand_string(condition);
 760 if (ss == NULL)
 761   {
 762   if (!expand_string_forcedfail && !search_find_defer)
 763     log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand condition \"%s\" "
 764       "for %s %s: %s", condition, m1, m2, expand_string_message);
 765   return FALSE;
 766   }
 767 rc = ss[0] != 0 && Ustrcmp(ss, "0") != 0 && strcmpic(ss, US"no") != 0 &&
 768   strcmpic(ss, US"false") != 0;
 769 store_reset(reset_point);
 770 return rc;
 771 }
 772
 773
 774
 775 /*************************************************
 776 *        Pseudo-random number generation         *
 777 *************************************************/
 778
 779 /* Pseudo-random number generation.  The result is not "expected" to be
 780 cryptographically strong but not so weak that someone will shoot themselves
 781 in the foot using it as a nonce in some email header scheme or whatever
 782 weirdness they'll twist this into.  The result should ideally handle fork().
 783
 784 However, if we're stuck unable to provide this, then we'll fall back to
 785 appallingly bad randomness.
 786
 787 If SUPPORT_TLS is defined and OpenSSL is used, then this will not be used.
 788 The GNUTLS randomness functions found do not seem amenable to extracting
 789 random numbers outside of a TLS context.  Any volunteers?
 790
 791 Arguments:
 792   max       range maximum
 793 Returns     a random number in range [0, max-1]
 794 */
 795
 796 #if !defined(SUPPORT_TLS) || defined(USE_GNUTLS)
 797 int
 798 pseudo_random_number(int max)
 799 {
 800   static pid_t pid = 0;
 801   pid_t p2;
 802 #if defined(HAVE_SRANDOM) && !defined(HAVE_SRANDOMDEV)
 803   struct timeval tv;
 804 #endif
 805
 806   p2 = getpid();
 807   if (p2 != pid)
 808     {
 809     if (pid != 0)
 810       {
 811
 812 #ifdef HAVE_ARC4RANDOM
 813       /* cryptographically strong randomness, common on *BSD platforms, not
 814       so much elsewhere.  Alas. */
 815       arc4random_stir();
 816 #elif defined(HAVE_SRANDOM) || defined(HAVE_SRANDOMDEV)
 817 #ifdef HAVE_SRANDOMDEV
 818       /* uses random(4) for seeding */
 819       srandomdev();
 820 #else
 821       gettimeofday(&tv, NULL);
 822       srandom(tv.tv_sec | tv.tv_usec | getpid());
 823 #endif
 824 #else
 825       /* Poor randomness and no seeding here */
 826 #endif
 827
 828       }
 829     pid = p2;
 830     }
 831
 832 #ifdef HAVE_ARC4RANDOM
 833   return arc4random() % max;
 834 #elif defined(HAVE_SRANDOM) || defined(HAVE_SRANDOMDEV)
 835   return random() % max;
 836 #else
 837   /* This one returns a 16-bit number, definitely not crypto-strong */
 838   return random_number(max);
 839 #endif
 840 }
 841
 842 #endif
 843
 844 /*************************************************
 845 *             Pick out a name from a string      *
 846 *************************************************/
 847
 848 /* If the name is too long, it is silently truncated.
 849
 850 Arguments:
 851   name      points to a buffer into which to put the name
 852   max       is the length of the buffer
 853   s         points to the first alphabetic character of the name
 854   extras    chars other than alphanumerics to permit
 855
 856 Returns:    pointer to the first character after the name
 857
 858 Note: The test for *s != 0 in the while loop is necessary because
 859 Ustrchr() yields non-NULL if the character is zero (which is not something
 860 I expected). */
 861
 862 static uschar *
 863 read_name(uschar *name, int max, uschar *s, uschar *extras)
 864 {
 865 int ptr = 0;
 866 while (*s != 0 && (isalnum(*s) || Ustrchr(extras, *s) != NULL))
 867   {
 868   if (ptr < max-1) name[ptr++] = *s;
 869   s++;
 870   }
 871 name[ptr] = 0;
 872 return s;
 873 }
 874
 875
 876
 877 /*************************************************
 878 *     Pick out the rest of a header name         *
 879 *************************************************/
 880
 881 /* A variable name starting $header_ (or just $h_ for those who like
 882 abbreviations) might not be the complete header name because headers can
 883 contain any printing characters in their names, except ':'. This function is
 884 called to read the rest of the name, chop h[eader]_ off the front, and put ':'
 885 on the end, if the name was terminated by white space.
 886
 887 Arguments:
 888   name      points to a buffer in which the name read so far exists
 889   max       is the length of the buffer
 890   s         points to the first character after the name so far, i.e. the
 891             first non-alphameric character after $header_xxxxx
 892
 893 Returns:    a pointer to the first character after the header name
 894 */
 895
 896 static uschar *
 897 read_header_name(uschar *name, int max, uschar *s)
 898 {
 899 int prelen = Ustrchr(name, '_') - name + 1;
 900 int ptr = Ustrlen(name) - prelen;
 901 if (ptr > 0) memmove(name, name+prelen, ptr);
 902 while (mac_isgraph(*s) && *s != ':')
 903   {
 904   if (ptr < max-1) name[ptr++] = *s;
 905   s++;
 906   }
 907 if (*s == ':') s++;
 908 name[ptr++] = ':';
 909 name[ptr] = 0;
 910 return s;
 911 }
 912
 913
 914
 915 /*************************************************
 916 *           Pick out a number from a string      *
 917 *************************************************/
 918
 919 /* Arguments:
 920   n     points to an integer into which to put the number
 921   s     points to the first digit of the number
 922
 923 Returns:  a pointer to the character after the last digit
 924 */
 925
 926 static uschar *
 927 read_number(int *n, uschar *s)
 928 {
 929 *n = 0;
 930 while (isdigit(*s)) *n = *n * 10 + (*s++ - '0');
 931 return s;
 932 }
 933
 934
 935
 936 /*************************************************
 937 *        Extract keyed subfield from a string    *
 938 *************************************************/
 939
 940 /* The yield is in dynamic store; NULL means that the key was not found.
 941
 942 Arguments:
 943   key       points to the name of the key
 944   s         points to the string from which to extract the subfield
 945
 946 Returns:    NULL if the subfield was not found, or
 947             a pointer to the subfield's data
 948 */
 949
 950 static uschar *
 951 expand_getkeyed(uschar *key, uschar *s)
 952 {
 953 int length = Ustrlen(key);
 954 while (isspace(*s)) s++;
 955
 956 /* Loop to search for the key */
 957
 958 while (*s != 0)
 959   {
 960   int dkeylength;
 961   uschar *data;
 962   uschar *dkey = s;
 963
 964   while (*s != 0 && *s != '=' && !isspace(*s)) s++;
 965   dkeylength = s - dkey;
 966   while (isspace(*s)) s++;
 967   if (*s == '=') while (isspace((*(++s))));
 968
 969   data = string_dequote(&s);
 970   if (length == dkeylength && strncmpic(key, dkey, length) == 0)
 971     return data;
 972
 973   while (isspace(*s)) s++;
 974   }
 975
 976 return NULL;
 977 }
 978
 979
 980
 981
 982 /*************************************************
 983 *   Extract numbered subfield from string        *
 984 *************************************************/
 985
 986 /* Extracts a numbered field from a string that is divided by tokens - for
 987 example a line from /etc/passwd is divided by colon characters.  First field is
 988 numbered one.  Negative arguments count from the right. Zero returns the whole
 989 string. Returns NULL if there are insufficient tokens in the string
 990
 991 ***WARNING***
 992 Modifies final argument - this is a dynamically generated string, so that's OK.
 993
 994 Arguments:
 995   field       number of field to be extracted,
 996                 first field = 1, whole string = 0, last field = -1
 997   separators  characters that are used to break string into tokens
 998   s           points to the string from which to extract the subfield
 999
1000 Returns:      NULL if the field was not found,
1001               a pointer to the field's data inside s (modified to add 0)
1002 */
1003
1004 static uschar *
1005 expand_gettokened (int field, uschar *separators, uschar *s)
1006 {
1007 int sep = 1;
1008 int count;
1009 uschar *ss = s;
1010 uschar *fieldtext = NULL;
1011
1012 if (field == 0) return s;
1013
1014 /* Break the line up into fields in place; for field > 0 we stop when we have
1015 done the number of fields we want. For field < 0 we continue till the end of
1016 the string, counting the number of fields. */
1017
1018 count = (field > 0)? field : INT_MAX;
1019
1020 while (count-- > 0)
1021   {
1022   size_t len;
1023
1024   /* Previous field was the last one in the string. For a positive field
1025   number, this means there are not enough fields. For a negative field number,
1026   check that there are enough, and scan back to find the one that is wanted. */
1027
1028   if (sep == 0)
1029     {
1030     if (field > 0 || (-field) > (INT_MAX - count - 1)) return NULL;
1031     if ((-field) == (INT_MAX - count - 1)) return s;
1032     while (field++ < 0)
1033       {
1034       ss--;
1035       while (ss[-1] != 0) ss--;
1036       }
1037     fieldtext = ss;
1038     break;
1039     }
1040
1041   /* Previous field was not last in the string; save its start and put a
1042   zero at its end. */
1043
1044   fieldtext = ss;
1045   len = Ustrcspn(ss, separators);
1046   sep = ss[len];
1047   ss[len] = 0;
1048   ss += len + 1;
1049   }
1050
1051 return fieldtext;
1052 }
1053
1054
1055
1056 /*************************************************
1057 *        Extract a substring from a string       *
1058 *************************************************/
1059
1060 /* Perform the ${substr or ${length expansion operations.
1061
1062 Arguments:
1063   subject     the input string
1064   value1      the offset from the start of the input string to the start of
1065                 the output string; if negative, count from the right.
1066   value2      the length of the output string, or negative (-1) for unset
1067                 if value1 is positive, unset means "all after"
1068                 if value1 is negative, unset means "all before"
1069   len         set to the length of the returned string
1070
1071 Returns:      pointer to the output string, or NULL if there is an error
1072 */
1073
1074 static uschar *
1075 extract_substr(uschar *subject, int value1, int value2, int *len)
1076 {
1077 int sublen = Ustrlen(subject);
1078
1079 if (value1 < 0)    /* count from right */
1080   {
1081   value1 += sublen;
1082
1083   /* If the position is before the start, skip to the start, and adjust the
1084   length. If the length ends up negative, the substring is null because nothing
1085   can precede. This falls out naturally when the length is unset, meaning "all
1086   to the left". */
1087
1088   if (value1 < 0)
1089     {
1090     value2 += value1;
1091     if (value2 < 0) value2 = 0;
1092     value1 = 0;
1093     }
1094
1095   /* Otherwise an unset length => characters before value1 */
1096
1097   else if (value2 < 0)
1098     {
1099     value2 = value1;
1100     value1 = 0;
1101     }
1102   }
1103
1104 /* For a non-negative offset, if the starting position is past the end of the
1105 string, the result will be the null string. Otherwise, an unset length means
1106 "rest"; just set it to the maximum - it will be cut down below if necessary. */
1107
1108 else
1109   {
1110   if (value1 > sublen)
1111     {
1112     value1 = sublen;
1113     value2 = 0;
1114     }
1115   else if (value2 < 0) value2 = sublen;
1116   }
1117
1118 /* Cut the length down to the maximum possible for the offset value, and get
1119 the required characters. */
1120
1121 if (value1 + value2 > sublen) value2 = sublen - value1;
1122 *len = value2;
1123 return subject + value1;
1124 }
1125
1126
1127
1128
1129 /*************************************************
1130 *            Old-style hash of a string          *
1131 *************************************************/
1132
1133 /* Perform the ${hash expansion operation.
1134
1135 Arguments:
1136   subject     the input string (an expanded substring)
1137   value1      the length of the output string; if greater or equal to the
1138                 length of the input string, the input string is returned
1139   value2      the number of hash characters to use, or 26 if negative
1140   len         set to the length of the returned string
1141
1142 Returns:      pointer to the output string, or NULL if there is an error
1143 */
1144
1145 static uschar *
1146 compute_hash(uschar *subject, int value1, int value2, int *len)
1147 {
1148 int sublen = Ustrlen(subject);
1149
1150 if (value2 < 0) value2 = 26;
1151 else if (value2 > Ustrlen(hashcodes))
1152   {
1153   expand_string_message =
1154     string_sprintf("hash count \"%d\" too big", value2);
1155   return NULL;
1156   }
1157
1158 /* Calculate the hash text. We know it is shorter than the original string, so
1159 can safely place it in subject[] (we know that subject is always itself an
1160 expanded substring). */
1161
1162 if (value1 < sublen)
1163   {
1164   int c;
1165   int i = 0;
1166   int j = value1;
1167   while ((c = (subject[j])) != 0)
1168     {
1169     int shift = (c + j++) & 7;
1170     subject[i] ^= (c << shift) | (c >> (8-shift));
1171     if (++i >= value1) i = 0;
1172     }
1173   for (i = 0; i < value1; i++)
1174     subject[i] = hashcodes[(subject[i]) % value2];
1175   }
1176 else value1 = sublen;
1177
1178 *len = value1;
1179 return subject;
1180 }
1181
1182
1183
1184
1185 /*************************************************
1186 *             Numeric hash of a string           *
1187 *************************************************/
1188
1189 /* Perform the ${nhash expansion operation. The first characters of the
1190 string are treated as most important, and get the highest prime numbers.
1191
1192 Arguments:
1193   subject     the input string
1194   value1      the maximum value of the first part of the result
1195   value2      the maximum value of the second part of the result,
1196                 or negative to produce only a one-part result
1197   len         set to the length of the returned string
1198
1199 Returns:  pointer to the output string, or NULL if there is an error.
1200 */
1201
1202 static uschar *
1203 compute_nhash (uschar *subject, int value1, int value2, int *len)
1204 {
1205 uschar *s = subject;
1206 int i = 0;
1207 unsigned long int total = 0; /* no overflow */
1208
1209 while (*s != 0)
1210   {
1211   if (i == 0) i = sizeof(prime)/sizeof(int) - 1;
1212   total += prime[i--] * (unsigned int)(*s++);
1213   }
1214
1215 /* If value2 is unset, just compute one number */
1216
1217 if (value2 < 0)
1218   {
1219   s = string_sprintf("%d", total % value1);
1220   }
1221
1222 /* Otherwise do a div/mod hash */
1223
1224 else
1225   {
1226   total = total % (value1 * value2);
1227   s = string_sprintf("%d/%d", total/value2, total % value2);
1228   }
1229
1230 *len = Ustrlen(s);
1231 return s;
1232 }
1233
1234
1235
1236
1237
1238 /*************************************************
1239 *     Find the value of a header or headers      *
1240 *************************************************/
1241
1242 /* Multiple instances of the same header get concatenated, and this function
1243 can also return a concatenation of all the header lines. When concatenating
1244 specific headers that contain lists of addresses, a comma is inserted between
1245 them. Otherwise we use a straight concatenation. Because some messages can have
1246 pathologically large number of lines, there is a limit on the length that is
1247 returned. Also, to avoid massive store use which would result from using
1248 string_cat() as it copies and extends strings, we do a preliminary pass to find
1249 out exactly how much store will be needed. On "normal" messages this will be
1250 pretty trivial.
1251
1252 Arguments:
1253   name          the name of the header, without the leading $header_ or $h_,
1254                 or NULL if a concatenation of all headers is required
1255   exists_only   TRUE if called from a def: test; don't need to build a string;
1256                 just return a string that is not "" and not "0" if the header
1257                 exists
1258   newsize       return the size of memory block that was obtained; may be NULL
1259                 if exists_only is TRUE
1260   want_raw      TRUE if called for $rh_ or $rheader_ variables; no processing,
1261                 other than concatenating, will be done on the header. Also used
1262                 for $message_headers_raw.
1263   charset       name of charset to translate MIME words to; used only if
1264                 want_raw is false; if NULL, no translation is done (this is
1265                 used for $bh_ and $bheader_)
1266
1267 Returns:        NULL if the header does not exist, else a pointer to a new
1268                 store block
1269 */
1270
1271 static uschar *
1272 find_header(uschar *name, BOOL exists_only, int *newsize, BOOL want_raw,
1273   uschar *charset)
1274 {
1275 BOOL found = name == NULL;
1276 int comma = 0;
1277 int len = found? 0 : Ustrlen(name);
1278 int i;
1279 uschar *yield = NULL;
1280 uschar *ptr = NULL;
1281
1282 /* Loop for two passes - saves code repetition */
1283
1284 for (i = 0; i < 2; i++)
1285   {
1286   int size = 0;
1287   header_line *h;
1288
1289   for (h = header_list; size < header_insert_maxlen && h != NULL; h = h->next)
1290     {
1291     if (h->type != htype_old && h->text != NULL)  /* NULL => Received: placeholder */
1292       {
1293       if (name == NULL || (len <= h->slen && strncmpic(name, h->text, len) == 0))
1294         {
1295         int ilen;
1296         uschar *t;
1297
1298         if (exists_only) return US"1";      /* don't need actual string */
1299         found = TRUE;
1300         t = h->text + len;                  /* text to insert */
1301         if (!want_raw)                      /* unless wanted raw, */
1302           while (isspace(*t)) t++;          /* remove leading white space */
1303         ilen = h->slen - (t - h->text);     /* length to insert */
1304
1305         /* Unless wanted raw, remove trailing whitespace, including the
1306         newline. */
1307
1308         if (!want_raw)
1309           while (ilen > 0 && isspace(t[ilen-1])) ilen--;
1310
1311         /* Set comma = 1 if handling a single header and it's one of those
1312         that contains an address list, except when asked for raw headers. Only
1313         need to do this once. */
1314
1315         if (!want_raw && name != NULL && comma == 0 &&
1316             Ustrchr("BCFRST", h->type) != NULL)
1317           comma = 1;
1318
1319         /* First pass - compute total store needed; second pass - compute
1320         total store used, including this header. */
1321
1322         size += ilen + comma + 1;  /* +1 for the newline */
1323
1324         /* Second pass - concatentate the data, up to a maximum. Note that
1325         the loop stops when size hits the limit. */
1326
1327         if (i != 0)
1328           {
1329           if (size > header_insert_maxlen)
1330             {
1331             ilen -= size - header_insert_maxlen - 1;
1332             comma = 0;
1333             }
1334           Ustrncpy(ptr, t, ilen);
1335           ptr += ilen;
1336
1337           /* For a non-raw header, put in the comma if needed, then add
1338           back the newline we removed above, provided there was some text in
1339           the header. */
1340
1341           if (!want_raw && ilen > 0)
1342             {
1343             if (comma != 0) *ptr++ = ',';
1344             *ptr++ = '\n';
1345             }
1346           }
1347         }
1348       }
1349     }
1350
1351   /* At end of first pass, return NULL if no header found. Then truncate size
1352   if necessary, and get the buffer to hold the data, returning the buffer size.
1353   */
1354
1355   if (i == 0)
1356     {
1357     if (!found) return NULL;
1358     if (size > header_insert_maxlen) size = header_insert_maxlen;
1359     *newsize = size + 1;
1360     ptr = yield = store_get(*newsize);
1361     }
1362   }
1363
1364 /* That's all we do for raw header expansion. */
1365
1366 if (want_raw)
1367   {
1368   *ptr = 0;
1369   }
1370
1371 /* Otherwise, remove a final newline and a redundant added comma. Then we do
1372 RFC 2047 decoding, translating the charset if requested. The rfc2047_decode2()
1373 function can return an error with decoded data if the charset translation
1374 fails. If decoding fails, it returns NULL. */
1375
1376 else
1377   {
1378   uschar *decoded, *error;
1379   if (ptr > yield && ptr[-1] == '\n') ptr--;
1380   if (ptr > yield && comma != 0 && ptr[-1] == ',') ptr--;
1381   *ptr = 0;
1382   decoded = rfc2047_decode2(yield, check_rfc2047_length, charset, '?', NULL,
1383     newsize, &error);
1384   if (error != NULL)
1385     {
1386     DEBUG(D_any) debug_printf("*** error in RFC 2047 decoding: %s\n"
1387       "    input was: %s\n", error, yield);
1388     }
1389   if (decoded != NULL) yield = decoded;
1390   }
1391
1392 return yield;
1393 }
1394
1395
1396
1397
1398 /*************************************************
1399 *               Find value of a variable         *
1400 *************************************************/
1401
1402 /* The table of variables is kept in alphabetic order, so we can search it
1403 using a binary chop. The "choplen" variable is nothing to do with the binary
1404 chop.
1405
1406 Arguments:
1407   name          the name of the variable being sought
1408   exists_only   TRUE if this is a def: test; passed on to find_header()
1409   skipping      TRUE => skip any processing evaluation; this is not the same as
1410                   exists_only because def: may test for values that are first
1411                   evaluated here
1412   newsize       pointer to an int which is initially zero; if the answer is in
1413                 a new memory buffer, *newsize is set to its size
1414
1415 Returns:        NULL if the variable does not exist, or
1416                 a pointer to the variable's contents, or
1417                 something non-NULL if exists_only is TRUE
1418 */
1419
1420 static uschar *
1421 find_variable(uschar *name, BOOL exists_only, BOOL skipping, int *newsize)
1422 {
1423 int first = 0;
1424 int last = var_table_size;
1425
1426 /* Handle ACL variables, whose names are of the form acl_cxxx or acl_mxxx.
1427 Originally, xxx had to be a number in the range 0-9 (later 0-19), but from
1428 release 4.64 onwards arbitrary names are permitted, as long as the first 5
1429 characters are acl_c or acl_m and the sixth is either a digit or an underscore
1430 (this gave backwards compatibility at the changeover). There may be built-in
1431 variables whose names start acl_ but they should never start in this way. This
1432 slightly messy specification is a consequence of the history, needless to say.
1433
1434 If an ACL variable does not exist, treat it as empty, unless strict_acl_vars is
1435 set, in which case give an error. */
1436
1437 if ((Ustrncmp(name, "acl_c", 5) == 0 || Ustrncmp(name, "acl_m", 5) == 0) &&
1438      !isalpha(name[5]))
1439   {
1440   tree_node *node =
1441     tree_search((name[4] == 'c')? acl_var_c : acl_var_m, name + 4);
1442   return (node == NULL)? (strict_acl_vars? NULL : US"") : node->data.ptr;
1443   }
1444
1445 /* Handle $auth<n> variables. */
1446
1447 if (Ustrncmp(name, "auth", 4) == 0)
1448   {
1449   uschar *endptr;
1450   int n = Ustrtoul(name + 4, &endptr, 10);
1451   if (*endptr == 0 && n != 0 && n <= AUTH_VARS)
1452     return (auth_vars[n-1] == NULL)? US"" : auth_vars[n-1];
1453   }
1454
1455 /* For all other variables, search the table */
1456
1457 while (last > first)
1458   {
1459   uschar *s, *domain;
1460   uschar **ss;
1461   int middle = (first + last)/2;
1462   int c = Ustrcmp(name, var_table[middle].name);
1463
1464   if (c > 0) { first = middle + 1; continue; }
1465   if (c < 0) { last = middle; continue; }
1466
1467   /* Found an existing variable. If in skipping state, the value isn't needed,
1468   and we want to avoid processing (such as looking up the host name). */
1469
1470   if (skipping) return US"";
1471
1472   switch (var_table[middle].type)
1473     {
1474     case vtype_filter_int:
1475     if (!filter_running) return NULL;
1476     /* Fall through */
1477     /* VVVVVVVVVVVV */
1478     case vtype_int:
1479     sprintf(CS var_buffer, "%d", *(int *)(var_table[middle].value)); /* Integer */
1480     return var_buffer;
1481
1482     case vtype_ino:
1483     sprintf(CS var_buffer, "%ld", (long int)(*(ino_t *)(var_table[middle].value))); /* Inode */
1484     return var_buffer;
1485
1486     case vtype_gid:
1487     sprintf(CS var_buffer, "%ld", (long int)(*(gid_t *)(var_table[middle].value))); /* gid */
1488     return var_buffer;
1489
1490     case vtype_uid:
1491     sprintf(CS var_buffer, "%ld", (long int)(*(uid_t *)(var_table[middle].value))); /* uid */
1492     return var_buffer;
1493
1494     case vtype_stringptr:                      /* Pointer to string */
1495     s = *((uschar **)(var_table[middle].value));
1496     return (s == NULL)? US"" : s;
1497
1498     case vtype_pid:
1499     sprintf(CS var_buffer, "%d", (int)getpid()); /* pid */
1500     return var_buffer;
1501
1502     case vtype_load_avg:
1503     sprintf(CS var_buffer, "%d", OS_GETLOADAVG()); /* load_average */
1504     return var_buffer;
1505
1506     case vtype_host_lookup:                    /* Lookup if not done so */
1507     if (sender_host_name == NULL && sender_host_address != NULL &&
1508         !host_lookup_failed && host_name_lookup() == OK)
1509       host_build_sender_fullhost();
1510     return (sender_host_name == NULL)? US"" : sender_host_name;
1511
1512     case vtype_localpart:                      /* Get local part from address */
1513     s = *((uschar **)(var_table[middle].value));
1514     if (s == NULL) return US"";
1515     domain = Ustrrchr(s, '@');
1516     if (domain == NULL) return s;
1517     if (domain - s > sizeof(var_buffer) - 1)
1518       log_write(0, LOG_MAIN|LOG_PANIC_DIE, "local part longer than %d in "
1519         "string expansion", sizeof(var_buffer));
1520     Ustrncpy(var_buffer, s, domain - s);
1521     var_buffer[domain - s] = 0;
1522     return var_buffer;
1523
1524     case vtype_domain:                         /* Get domain from address */
1525     s = *((uschar **)(var_table[middle].value));
1526     if (s == NULL) return US"";
1527     domain = Ustrrchr(s, '@');
1528     return (domain == NULL)? US"" : domain + 1;
1529
1530     case vtype_msgheaders:
1531     return find_header(NULL, exists_only, newsize, FALSE, NULL);
1532
1533     case vtype_msgheaders_raw:
1534     return find_header(NULL, exists_only, newsize, TRUE, NULL);
1535
1536     case vtype_msgbody:                        /* Pointer to msgbody string */
1537     case vtype_msgbody_end:                    /* Ditto, the end of the msg */
1538     ss = (uschar **)(var_table[middle].value);
1539     if (*ss == NULL && deliver_datafile >= 0)  /* Read body when needed */
1540       {
1541       uschar *body;
1542       off_t start_offset = SPOOL_DATA_START_OFFSET;
1543       int len = message_body_visible;
1544       if (len > message_size) len = message_size;
1545       *ss = body = store_malloc(len+1);
1546       body[0] = 0;
1547       if (var_table[middle].type == vtype_msgbody_end)
1548         {
1549         struct stat statbuf;
1550         if (fstat(deliver_datafile, &statbuf) == 0)
1551           {
1552           start_offset = statbuf.st_size - len;
1553           if (start_offset < SPOOL_DATA_START_OFFSET)
1554             start_offset = SPOOL_DATA_START_OFFSET;
1555           }
1556         }
1557       lseek(deliver_datafile, start_offset, SEEK_SET);
1558       len = read(deliver_datafile, body, len);
1559       if (len > 0)
1560         {
1561         body[len] = 0;
1562         if (message_body_newlines)   /* Separate loops for efficiency */
1563           {
1564           while (len > 0)
1565             { if (body[--len] == 0) body[len] = ' '; }
1566           }
1567         else
1568           {
1569           while (len > 0)
1570             { if (body[--len] == '\n' || body[len] == 0) body[len] = ' '; }
1571           }
1572         }
1573       }
1574     return (*ss == NULL)? US"" : *ss;
1575
1576     case vtype_todbsdin:                       /* BSD inbox time of day */
1577     return tod_stamp(tod_bsdin);
1578
1579     case vtype_tode:                           /* Unix epoch time of day */
1580     return tod_stamp(tod_epoch);
1581
1582     case vtype_todf:                           /* Full time of day */
1583     return tod_stamp(tod_full);
1584
1585     case vtype_todl:                           /* Log format time of day */
1586     return tod_stamp(tod_log_bare);            /* (without timezone) */
1587
1588     case vtype_todzone:                        /* Time zone offset only */
1589     return tod_stamp(tod_zone);
1590
1591     case vtype_todzulu:                        /* Zulu time */
1592     return tod_stamp(tod_zulu);
1593
1594     case vtype_todlf:                          /* Log file datestamp tod */
1595     return tod_stamp(tod_log_datestamp_daily);
1596
1597     case vtype_reply:                          /* Get reply address */
1598     s = find_header(US"reply-to:", exists_only, newsize, TRUE,
1599       headers_charset);
1600     if (s != NULL) while (isspace(*s)) s++;
1601     if (s == NULL || *s == 0)
1602       {
1603       *newsize = 0;                            /* For the *s==0 case */
1604       s = find_header(US"from:", exists_only, newsize, TRUE, headers_charset);
1605       }
1606     if (s != NULL)
1607       {
1608       uschar *t;
1609       while (isspace(*s)) s++;
1610       for (t = s; *t != 0; t++) if (*t == '\n') *t = ' ';
1611       while (t > s && isspace(t[-1])) t--;
1612       *t = 0;
1613       }
1614     return (s == NULL)? US"" : s;
1615
1616     /* A recipients list is available only during system message filtering,
1617     during ACL processing after DATA, and while expanding pipe commands
1618     generated from a system filter, but not elsewhere. */
1619
1620     case vtype_recipients:
1621     if (!enable_dollar_recipients) return NULL; else
1622       {
1623       int size = 128;
1624       int ptr = 0;
1625       int i;
1626       s = store_get(size);
1627       for (i = 0; i < recipients_count; i++)
1628         {
1629         if (i != 0) s = string_cat(s, &size, &ptr, US", ", 2);
1630         s = string_cat(s, &size, &ptr, recipients_list[i].address,
1631           Ustrlen(recipients_list[i].address));
1632         }
1633       s[ptr] = 0;     /* string_cat() leaves room */
1634       }
1635     return s;
1636
1637     case vtype_pspace:
1638       {
1639       int inodes;
1640       sprintf(CS var_buffer, "%d",
1641         receive_statvfs(var_table[middle].value == (void *)TRUE, &inodes));
1642       }
1643     return var_buffer;
1644
1645     case vtype_pinodes:
1646       {
1647       int inodes;
1648       (void) receive_statvfs(var_table[middle].value == (void *)TRUE, &inodes);
1649       sprintf(CS var_buffer, "%d", inodes);
1650       }
1651     return var_buffer;
1652
1653     #ifndef DISABLE_DKIM
1654     case vtype_dkim:
1655     return dkim_exim_expand_query((int)(long)var_table[middle].value);
1656     #endif
1657
1658     }
1659   }
1660
1661 return NULL;          /* Unknown variable name */
1662 }
1663
1664
1665
1666
1667 /*************************************************
1668 *           Read and expand substrings           *
1669 *************************************************/
1670
1671 /* This function is called to read and expand argument substrings for various
1672 expansion items. Some have a minimum requirement that is less than the maximum;
1673 in these cases, the first non-present one is set to NULL.
1674
1675 Arguments:
1676   sub        points to vector of pointers to set
1677   n          maximum number of substrings
1678   m          minimum required
1679   sptr       points to current string pointer
1680   skipping   the skipping flag
1681   check_end  if TRUE, check for final '}'
1682   name       name of item, for error message
1683
1684 Returns:     0 OK; string pointer updated
1685              1 curly bracketing error (too few arguments)
1686              2 too many arguments (only if check_end is set); message set
1687              3 other error (expansion failure)
1688 */
1689
1690 static int
1691 read_subs(uschar **sub, int n, int m, uschar **sptr, BOOL skipping,
1692   BOOL check_end, uschar *name)
1693 {
1694 int i;
1695 uschar *s = *sptr;
1696
1697 while (isspace(*s)) s++;
1698 for (i = 0; i < n; i++)
1699   {
1700   if (*s != '{')
1701     {
1702     if (i < m) return 1;
1703     sub[i] = NULL;
1704     break;
1705     }
1706   sub[i] = expand_string_internal(s+1, TRUE, &s, skipping, TRUE);
1707   if (sub[i] == NULL) return 3;
1708   if (*s++ != '}') return 1;
1709   while (isspace(*s)) s++;
1710   }
1711 if (check_end && *s++ != '}')
1712   {
1713   if (s[-1] == '{')
1714     {
1715     expand_string_message = string_sprintf("Too many arguments for \"%s\" "
1716       "(max is %d)", name, n);
1717     return 2;
1718     }
1719   return 1;
1720   }
1721
1722 *sptr = s;
1723 return 0;
1724 }
1725
1726
1727
1728
1729 /*************************************************
1730 *     Elaborate message for bad variable         *
1731 *************************************************/
1732
1733 /* For the "unknown variable" message, take a look at the variable's name, and
1734 give additional information about possible ACL variables. The extra information
1735 is added on to expand_string_message.
1736
1737 Argument:   the name of the variable
1738 Returns:    nothing
1739 */
1740
1741 static void
1742 check_variable_error_message(uschar *name)
1743 {
1744 if (Ustrncmp(name, "acl_", 4) == 0)
1745   expand_string_message = string_sprintf("%s (%s)", expand_string_message,
1746     (name[4] == 'c' || name[4] == 'm')?
1747       (isalpha(name[5])?
1748         US"6th character of a user-defined ACL variable must be a digit or underscore" :
1749         US"strict_acl_vars is set"    /* Syntax is OK, it has to be this */
1750       ) :
1751       US"user-defined ACL variables must start acl_c or acl_m");
1752 }
1753
1754
1755
1756 /*************************************************
1757 *        Read and evaluate a condition           *
1758 *************************************************/
1759
1760 /*
1761 Arguments:
1762   s        points to the start of the condition text
1763   yield    points to a BOOL to hold the result of the condition test;
1764            if NULL, we are just reading through a condition that is
1765            part of an "or" combination to check syntax, or in a state
1766            where the answer isn't required
1767
1768 Returns:   a pointer to the first character after the condition, or
1769            NULL after an error
1770 */
1771
1772 static uschar *
1773 eval_condition(uschar *s, BOOL *yield)
1774 {
1775 BOOL testfor = TRUE;
1776 BOOL tempcond, combined_cond;
1777 BOOL *subcondptr;
1778 BOOL *sub2_honour_dollar = TRUE;
1779 int i, rc, cond_type, roffset;
1780 int num[2];
1781 struct stat statbuf;
1782 uschar name[256];
1783 uschar *sub[4];
1784
1785 const pcre *re;
1786 const uschar *rerror;
1787
1788 for (;;)
1789   {
1790   while (isspace(*s)) s++;
1791   if (*s == '!') { testfor = !testfor; s++; } else break;
1792   }
1793
1794 /* Numeric comparisons are symbolic */
1795
1796 if (*s == '=' || *s == '>' || *s == '<')
1797   {
1798   int p = 0;
1799   name[p++] = *s++;
1800   if (*s == '=')
1801     {
1802     name[p++] = '=';
1803     s++;
1804     }
1805   name[p] = 0;
1806   }
1807
1808 /* All other conditions are named */
1809
1810 else s = read_name(name, 256, s, US"_");
1811
1812 /* If we haven't read a name, it means some non-alpha character is first. */
1813
1814 if (name[0] == 0)
1815   {
1816   expand_string_message = string_sprintf("condition name expected, "
1817     "but found \"%.16s\"", s);
1818   return NULL;
1819   }
1820
1821 /* Find which condition we are dealing with, and switch on it */
1822
1823 cond_type = chop_match(name, cond_table, sizeof(cond_table)/sizeof(uschar *));
1824 switch(cond_type)
1825   {
1826   /* def: tests for a non-empty variable, or for the existence of a header. If
1827   yield == NULL we are in a skipping state, and don't care about the answer. */
1828
1829   case ECOND_DEF:
1830   if (*s != ':')
1831     {
1832     expand_string_message = US"\":\" expected after \"def\"";
1833     return NULL;
1834     }
1835
1836   s = read_name(name, 256, s+1, US"_");
1837
1838   /* Test for a header's existence. If the name contains a closing brace
1839   character, this may be a user error where the terminating colon has been
1840   omitted. Set a flag to adjust a subsequent error message in this case. */
1841
1842   if (Ustrncmp(name, "h_", 2) == 0 ||
1843       Ustrncmp(name, "rh_", 3) == 0 ||
1844       Ustrncmp(name, "bh_", 3) == 0 ||
1845       Ustrncmp(name, "header_", 7) == 0 ||
1846       Ustrncmp(name, "rheader_", 8) == 0 ||
1847       Ustrncmp(name, "bheader_", 8) == 0)
1848     {
1849     s = read_header_name(name, 256, s);
1850     if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
1851     if (yield != NULL) *yield =
1852       (find_header(name, TRUE, NULL, FALSE, NULL) != NULL) == testfor;
1853     }
1854
1855   /* Test for a variable's having a non-empty value. A non-existent variable
1856   causes an expansion failure. */
1857
1858   else
1859     {
1860     uschar *value = find_variable(name, TRUE, yield == NULL, NULL);
1861     if (value == NULL)
1862       {
1863       expand_string_message = (name[0] == 0)?
1864         string_sprintf("variable name omitted after \"def:\"") :
1865         string_sprintf("unknown variable \"%s\" after \"def:\"", name);
1866       check_variable_error_message(name);
1867       return NULL;
1868       }
1869     if (yield != NULL) *yield = (value[0] != 0) == testfor;
1870     }
1871
1872   return s;
1873
1874
1875   /* first_delivery tests for first delivery attempt */
1876
1877   case ECOND_FIRST_DELIVERY:
1878   if (yield != NULL) *yield = deliver_firsttime == testfor;
1879   return s;
1880
1881
1882   /* queue_running tests for any process started by a queue runner */
1883
1884   case ECOND_QUEUE_RUNNING:
1885   if (yield != NULL) *yield = (queue_run_pid != (pid_t)0) == testfor;
1886   return s;
1887
1888
1889   /* exists:  tests for file existence
1890        isip:  tests for any IP address
1891       isip4:  tests for an IPv4 address
1892       isip6:  tests for an IPv6 address
1893         pam:  does PAM authentication
1894      radius:  does RADIUS authentication
1895    ldapauth:  does LDAP authentication
1896     pwcheck:  does Cyrus SASL pwcheck authentication
1897   */
1898
1899   case ECOND_EXISTS:
1900   case ECOND_ISIP:
1901   case ECOND_ISIP4:
1902   case ECOND_ISIP6:
1903   case ECOND_PAM:
1904   case ECOND_RADIUS:
1905   case ECOND_LDAPAUTH:
1906   case ECOND_PWCHECK:
1907
1908   while (isspace(*s)) s++;
1909   if (*s != '{') goto COND_FAILED_CURLY_START;
1910
1911   sub[0] = expand_string_internal(s+1, TRUE, &s, yield == NULL, TRUE);
1912   if (sub[0] == NULL) return NULL;
1913   if (*s++ != '}') goto COND_FAILED_CURLY_END;
1914
1915   if (yield == NULL) return s;   /* No need to run the test if skipping */
1916
1917   switch(cond_type)
1918     {
1919     case ECOND_EXISTS:
1920     if ((expand_forbid & RDO_EXISTS) != 0)
1921       {
1922       expand_string_message = US"File existence tests are not permitted";
1923       return NULL;
1924       }
1925     *yield = (Ustat(sub[0], &statbuf) == 0) == testfor;
1926     break;
1927
1928     case ECOND_ISIP:
1929     case ECOND_ISIP4:
1930     case ECOND_ISIP6:
1931     rc = string_is_ip_address(sub[0], NULL);
1932     *yield = ((cond_type == ECOND_ISIP)? (rc != 0) :
1933              (cond_type == ECOND_ISIP4)? (rc == 4) : (rc == 6)) == testfor;
1934     break;
1935
1936     /* Various authentication tests - all optionally compiled */
1937
1938     case ECOND_PAM:
1939     #ifdef SUPPORT_PAM
1940     rc = auth_call_pam(sub[0], &expand_string_message);
1941     goto END_AUTH;
1942     #else
1943     goto COND_FAILED_NOT_COMPILED;
1944     #endif  /* SUPPORT_PAM */
1945
1946     case ECOND_RADIUS:
1947     #ifdef RADIUS_CONFIG_FILE
1948     rc = auth_call_radius(sub[0], &expand_string_message);
1949     goto END_AUTH;
1950     #else
1951     goto COND_FAILED_NOT_COMPILED;
1952     #endif  /* RADIUS_CONFIG_FILE */
1953
1954     case ECOND_LDAPAUTH:
1955     #ifdef LOOKUP_LDAP
1956       {
1957       /* Just to keep the interface the same */
1958       BOOL do_cache;
1959       int old_pool = store_pool;
1960       store_pool = POOL_SEARCH;
1961       rc = eldapauth_find((void *)(-1), NULL, sub[0], Ustrlen(sub[0]), NULL,
1962         &expand_string_message, &do_cache);
1963       store_pool = old_pool;
1964       }
1965     goto END_AUTH;
1966     #else
1967     goto COND_FAILED_NOT_COMPILED;
1968     #endif  /* LOOKUP_LDAP */
1969
1970     case ECOND_PWCHECK:
1971     #ifdef CYRUS_PWCHECK_SOCKET
1972     rc = auth_call_pwcheck(sub[0], &expand_string_message);
1973     goto END_AUTH;
1974     #else
1975     goto COND_FAILED_NOT_COMPILED;
1976     #endif  /* CYRUS_PWCHECK_SOCKET */
1977
1978     #if defined(SUPPORT_PAM) || defined(RADIUS_CONFIG_FILE) || \
1979         defined(LOOKUP_LDAP) || defined(CYRUS_PWCHECK_SOCKET)
1980     END_AUTH:
1981     if (rc == ERROR || rc == DEFER) return NULL;
1982     *yield = (rc == OK) == testfor;
1983     #endif
1984     }
1985   return s;
1986
1987
1988   /* saslauthd: does Cyrus saslauthd authentication. Four parameters are used:
1989
1990      ${if saslauthd {{username}{password}{service}{realm}}  {yes}[no}}
1991
1992   However, the last two are optional. That is why the whole set is enclosed
1993   in their own set or braces. */
1994
1995   case ECOND_SASLAUTHD:
1996   #ifndef CYRUS_SASLAUTHD_SOCKET
1997   goto COND_FAILED_NOT_COMPILED;
1998   #else
1999   while (isspace(*s)) s++;
2000   if (*s++ != '{') goto COND_FAILED_CURLY_START;
2001   switch(read_subs(sub, 4, 2, &s, yield == NULL, TRUE, US"saslauthd"))
2002     {
2003     case 1: expand_string_message = US"too few arguments or bracketing "
2004       "error for saslauthd";
2005     case 2:
2006     case 3: return NULL;
2007     }
2008   if (sub[2] == NULL) sub[3] = NULL;  /* realm if no service */
2009   if (yield != NULL)
2010     {
2011     int rc;
2012     rc = auth_call_saslauthd(sub[0], sub[1], sub[2], sub[3],
2013       &expand_string_message);
2014     if (rc == ERROR || rc == DEFER) return NULL;
2015     *yield = (rc == OK) == testfor;
2016     }
2017   return s;
2018   #endif /* CYRUS_SASLAUTHD_SOCKET */
2019
2020
2021   /* symbolic operators for numeric and string comparison, and a number of
2022   other operators, all requiring two arguments.
2023
2024   crypteq:           encrypts plaintext and compares against an encrypted text,
2025                        using crypt(), crypt16(), MD5 or SHA-1
2026   inlist/inlisti:    checks if first argument is in the list of the second
2027   match:             does a regular expression match and sets up the numerical
2028                        variables if it succeeds
2029   match_address:     matches in an address list
2030   match_domain:      matches in a domain list
2031   match_ip:          matches a host list that is restricted to IP addresses
2032   match_local_part:  matches in a local part list
2033   */
2034
2035   case ECOND_MATCH_ADDRESS:
2036   case ECOND_MATCH_DOMAIN:
2037   case ECOND_MATCH_IP:
2038   case ECOND_MATCH_LOCAL_PART:
2039 #ifndef EXPAND_LISTMATCH_RHS
2040     sub2_honour_dollar = FALSE;
2041 #endif
2042     /* FALLTHROUGH */
2043
2044   case ECOND_CRYPTEQ:
2045   case ECOND_INLIST:
2046   case ECOND_INLISTI:
2047   case ECOND_MATCH:
2048
2049   case ECOND_NUM_L:     /* Numerical comparisons */
2050   case ECOND_NUM_LE:
2051   case ECOND_NUM_E:
2052   case ECOND_NUM_EE:
2053   case ECOND_NUM_G:
2054   case ECOND_NUM_GE:
2055
2056   case ECOND_STR_LT:    /* String comparisons */
2057   case ECOND_STR_LTI:
2058   case ECOND_STR_LE:
2059   case ECOND_STR_LEI:
2060   case ECOND_STR_EQ:
2061   case ECOND_STR_EQI:
2062   case ECOND_STR_GT:
2063   case ECOND_STR_GTI:
2064   case ECOND_STR_GE:
2065   case ECOND_STR_GEI:
2066
2067   for (i = 0; i < 2; i++)
2068     {
2069     /* Sometimes, we don't expand substrings; too many insecure configurations
2070     created using match_address{}{} and friends, where the second param
2071     includes information from untrustworthy sources. */
2072     BOOL honour_dollar = TRUE;
2073     if ((i > 0) && !sub2_honour_dollar)
2074       honour_dollar = FALSE;
2075
2076     while (isspace(*s)) s++;
2077     if (*s != '{')
2078       {
2079       if (i == 0) goto COND_FAILED_CURLY_START;
2080       expand_string_message = string_sprintf("missing 2nd string in {} "
2081         "after \"%s\"", name);
2082       return NULL;
2083       }
2084     sub[i] = expand_string_internal(s+1, TRUE, &s, yield == NULL,
2085         honour_dollar);
2086     if (sub[i] == NULL) return NULL;
2087     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2088
2089     /* Convert to numerical if required; we know that the names of all the
2090     conditions that compare numbers do not start with a letter. This just saves
2091     checking for them individually. */
2092
2093     if (!isalpha(name[0]) && yield != NULL)
2094       {
2095       if (sub[i][0] == 0)
2096         {
2097         num[i] = 0;
2098         DEBUG(D_expand)
2099           debug_printf("empty string cast to zero for numerical comparison\n");
2100         }
2101       else
2102         {
2103         num[i] = expand_string_integer(sub[i], FALSE);
2104         if (expand_string_message != NULL) return NULL;
2105         }
2106       }
2107     }
2108
2109   /* Result not required */
2110
2111   if (yield == NULL) return s;
2112
2113   /* Do an appropriate comparison */
2114
2115   switch(cond_type)
2116     {
2117     case ECOND_NUM_E:
2118     case ECOND_NUM_EE:
2119     *yield = (num[0] == num[1]) == testfor;
2120     break;
2121
2122     case ECOND_NUM_G:
2123     *yield = (num[0] > num[1]) == testfor;
2124     break;
2125
2126     case ECOND_NUM_GE:
2127     *yield = (num[0] >= num[1]) == testfor;
2128     break;
2129
2130     case ECOND_NUM_L:
2131     *yield = (num[0] < num[1]) == testfor;
2132     break;
2133
2134     case ECOND_NUM_LE:
2135     *yield = (num[0] <= num[1]) == testfor;
2136     break;
2137
2138     case ECOND_STR_LT:
2139     *yield = (Ustrcmp(sub[0], sub[1]) < 0) == testfor;
2140     break;
2141
2142     case ECOND_STR_LTI:
2143     *yield = (strcmpic(sub[0], sub[1]) < 0) == testfor;
2144     break;
2145
2146     case ECOND_STR_LE:
2147     *yield = (Ustrcmp(sub[0], sub[1]) <= 0) == testfor;
2148     break;
2149
2150     case ECOND_STR_LEI:
2151     *yield = (strcmpic(sub[0], sub[1]) <= 0) == testfor;
2152     break;
2153
2154     case ECOND_STR_EQ:
2155     *yield = (Ustrcmp(sub[0], sub[1]) == 0) == testfor;
2156     break;
2157
2158     case ECOND_STR_EQI:
2159     *yield = (strcmpic(sub[0], sub[1]) == 0) == testfor;
2160     break;
2161
2162     case ECOND_STR_GT:
2163     *yield = (Ustrcmp(sub[0], sub[1]) > 0) == testfor;
2164     break;
2165
2166     case ECOND_STR_GTI:
2167     *yield = (strcmpic(sub[0], sub[1]) > 0) == testfor;
2168     break;
2169
2170     case ECOND_STR_GE:
2171     *yield = (Ustrcmp(sub[0], sub[1]) >= 0) == testfor;
2172     break;
2173
2174     case ECOND_STR_GEI:
2175     *yield = (strcmpic(sub[0], sub[1]) >= 0) == testfor;
2176     break;
2177
2178     case ECOND_MATCH:   /* Regular expression match */
2179     re = pcre_compile(CS sub[1], PCRE_COPT, (const char **)&rerror, &roffset,
2180       NULL);
2181     if (re == NULL)
2182       {
2183       expand_string_message = string_sprintf("regular expression error in "
2184         "\"%s\": %s at offset %d", sub[1], rerror, roffset);
2185       return NULL;
2186       }
2187     *yield = regex_match_and_setup(re, sub[0], 0, -1) == testfor;
2188     break;
2189
2190     case ECOND_MATCH_ADDRESS:  /* Match in an address list */
2191     rc = match_address_list(sub[0], TRUE, FALSE, &(sub[1]), NULL, -1, 0, NULL);
2192     goto MATCHED_SOMETHING;
2193
2194     case ECOND_MATCH_DOMAIN:   /* Match in a domain list */
2195     rc = match_isinlist(sub[0], &(sub[1]), 0, &domainlist_anchor, NULL,
2196       MCL_DOMAIN + MCL_NOEXPAND, TRUE, NULL);
2197     goto MATCHED_SOMETHING;
2198
2199     case ECOND_MATCH_IP:       /* Match IP address in a host list */
2200     if (sub[0][0] != 0 && string_is_ip_address(sub[0], NULL) == 0)
2201       {
2202       expand_string_message = string_sprintf("\"%s\" is not an IP address",
2203         sub[0]);
2204       return NULL;
2205       }
2206     else
2207       {
2208       unsigned int *nullcache = NULL;
2209       check_host_block cb;
2210
2211       cb.host_name = US"";
2212       cb.host_address = sub[0];
2213
2214       /* If the host address starts off ::ffff: it is an IPv6 address in
2215       IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2216       addresses. */
2217
2218       cb.host_ipv4 = (Ustrncmp(cb.host_address, "::ffff:", 7) == 0)?
2219         cb.host_address + 7 : cb.host_address;
2220
2221       rc = match_check_list(
2222              &sub[1],                   /* the list */
2223              0,                         /* separator character */
2224              &hostlist_anchor,          /* anchor pointer */
2225              &nullcache,                /* cache pointer */
2226              check_host,                /* function for testing */
2227              &cb,                       /* argument for function */
2228              MCL_HOST,                  /* type of check */
2229              sub[0],                    /* text for debugging */
2230              NULL);                     /* where to pass back data */
2231       }
2232     goto MATCHED_SOMETHING;
2233
2234     case ECOND_MATCH_LOCAL_PART:
2235     rc = match_isinlist(sub[0], &(sub[1]), 0, &localpartlist_anchor, NULL,
2236       MCL_LOCALPART + MCL_NOEXPAND, TRUE, NULL);
2237     /* Fall through */
2238     /* VVVVVVVVVVVV */
2239     MATCHED_SOMETHING:
2240     switch(rc)
2241       {
2242       case OK:
2243       *yield = testfor;
2244       break;
2245
2246       case FAIL:
2247       *yield = !testfor;
2248       break;
2249
2250       case DEFER:
2251       expand_string_message = string_sprintf("unable to complete match "
2252         "against \"%s\": %s", sub[1], search_error_message);
2253       return NULL;
2254       }
2255
2256     break;
2257
2258     /* Various "encrypted" comparisons. If the second string starts with
2259     "{" then an encryption type is given. Default to crypt() or crypt16()
2260     (build-time choice). */
2261
2262     case ECOND_CRYPTEQ:
2263     #ifndef SUPPORT_CRYPTEQ
2264     goto COND_FAILED_NOT_COMPILED;
2265     #else
2266     if (strncmpic(sub[1], US"{md5}", 5) == 0)
2267       {
2268       int sublen = Ustrlen(sub[1]+5);
2269       md5 base;
2270       uschar digest[16];
2271
2272       md5_start(&base);
2273       md5_end(&base, (uschar *)sub[0], Ustrlen(sub[0]), digest);
2274
2275       /* If the length that we are comparing against is 24, the MD5 digest
2276       is expressed as a base64 string. This is the way LDAP does it. However,
2277       some other software uses a straightforward hex representation. We assume
2278       this if the length is 32. Other lengths fail. */
2279
2280       if (sublen == 24)
2281         {
2282         uschar *coded = auth_b64encode((uschar *)digest, 16);
2283         DEBUG(D_auth) debug_printf("crypteq: using MD5+B64 hashing\n"
2284           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2285         *yield = (Ustrcmp(coded, sub[1]+5) == 0) == testfor;
2286         }
2287       else if (sublen == 32)
2288         {
2289         int i;
2290         uschar coded[36];
2291         for (i = 0; i < 16; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2292         coded[32] = 0;
2293         DEBUG(D_auth) debug_printf("crypteq: using MD5+hex hashing\n"
2294           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2295         *yield = (strcmpic(coded, sub[1]+5) == 0) == testfor;
2296         }
2297       else
2298         {
2299         DEBUG(D_auth) debug_printf("crypteq: length for MD5 not 24 or 32: "
2300           "fail\n  crypted=%s\n", sub[1]+5);
2301         *yield = !testfor;
2302         }
2303       }
2304
2305     else if (strncmpic(sub[1], US"{sha1}", 6) == 0)
2306       {
2307       int sublen = Ustrlen(sub[1]+6);
2308       sha1 base;
2309       uschar digest[20];
2310
2311       sha1_start(&base);
2312       sha1_end(&base, (uschar *)sub[0], Ustrlen(sub[0]), digest);
2313
2314       /* If the length that we are comparing against is 28, assume the SHA1
2315       digest is expressed as a base64 string. If the length is 40, assume a
2316       straightforward hex representation. Other lengths fail. */
2317
2318       if (sublen == 28)
2319         {
2320         uschar *coded = auth_b64encode((uschar *)digest, 20);
2321         DEBUG(D_auth) debug_printf("crypteq: using SHA1+B64 hashing\n"
2322           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2323         *yield = (Ustrcmp(coded, sub[1]+6) == 0) == testfor;
2324         }
2325       else if (sublen == 40)
2326         {
2327         int i;
2328         uschar coded[44];
2329         for (i = 0; i < 20; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2330         coded[40] = 0;
2331         DEBUG(D_auth) debug_printf("crypteq: using SHA1+hex hashing\n"
2332           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2333         *yield = (strcmpic(coded, sub[1]+6) == 0) == testfor;
2334         }
2335       else
2336         {
2337         DEBUG(D_auth) debug_printf("crypteq: length for SHA-1 not 28 or 40: "
2338           "fail\n  crypted=%s\n", sub[1]+6);
2339         *yield = !testfor;
2340         }
2341       }
2342
2343     else   /* {crypt} or {crypt16} and non-{ at start */
2344            /* }-for-text-editors */
2345       {
2346       int which = 0;
2347       uschar *coded;
2348
2349       if (strncmpic(sub[1], US"{crypt}", 7) == 0)
2350         {
2351         sub[1] += 7;
2352         which = 1;
2353         }
2354       else if (strncmpic(sub[1], US"{crypt16}", 9) == 0)
2355         {
2356         sub[1] += 9;
2357         which = 2;
2358         }
2359       else if (sub[1][0] == '{')
2360         {
2361         expand_string_message = string_sprintf("unknown encryption mechanism "
2362           "in \"%s\"", sub[1]);
2363         return NULL;
2364         }
2365
2366       switch(which)
2367         {
2368         case 0:  coded = US DEFAULT_CRYPT(CS sub[0], CS sub[1]); break;
2369         case 1:  coded = US crypt(CS sub[0], CS sub[1]); break;
2370         default: coded = US crypt16(CS sub[0], CS sub[1]); break;
2371         }
2372
2373       #define STR(s) # s
2374       #define XSTR(s) STR(s)
2375       DEBUG(D_auth) debug_printf("crypteq: using %s()\n"
2376         "  subject=%s\n  crypted=%s\n",
2377         (which == 0)? XSTR(DEFAULT_CRYPT) : (which == 1)? "crypt" : "crypt16",
2378         coded, sub[1]);
2379       #undef STR
2380       #undef XSTR
2381
2382       /* If the encrypted string contains fewer than two characters (for the
2383       salt), force failure. Otherwise we get false positives: with an empty
2384       string the yield of crypt() is an empty string! */
2385
2386       *yield = (Ustrlen(sub[1]) < 2)? !testfor :
2387         (Ustrcmp(coded, sub[1]) == 0) == testfor;
2388       }
2389     break;
2390     #endif  /* SUPPORT_CRYPTEQ */
2391
2392     case ECOND_INLIST:
2393     case ECOND_INLISTI:
2394       {
2395       int sep = 0;
2396       BOOL found = FALSE;
2397       uschar *save_iterate_item = iterate_item;
2398       int (*compare)(const uschar *, const uschar *);
2399
2400       if (cond_type == ECOND_INLISTI)
2401         compare = strcmpic;
2402       else
2403         compare = (int (*)(const uschar *, const uschar *)) strcmp;
2404
2405       while ((iterate_item = string_nextinlist(&sub[1], &sep, NULL, 0)) != NULL)
2406         if (compare(sub[0], iterate_item) == 0)
2407           {
2408           found = TRUE;
2409           break;
2410           }
2411       iterate_item = save_iterate_item;
2412       *yield = found;
2413       }
2414
2415     }   /* Switch for comparison conditions */
2416
2417   return s;    /* End of comparison conditions */
2418
2419
2420   /* and/or: computes logical and/or of several conditions */
2421
2422   case ECOND_AND:
2423   case ECOND_OR:
2424   subcondptr = (yield == NULL)? NULL : &tempcond;
2425   combined_cond = (cond_type == ECOND_AND);
2426
2427   while (isspace(*s)) s++;
2428   if (*s++ != '{') goto COND_FAILED_CURLY_START;
2429
2430   for (;;)
2431     {
2432     while (isspace(*s)) s++;
2433     if (*s == '}') break;
2434     if (*s != '{')
2435       {
2436       expand_string_message = string_sprintf("each subcondition "
2437         "inside an \"%s{...}\" condition must be in its own {}", name);
2438       return NULL;
2439       }
2440
2441     s = eval_condition(s+1, subcondptr);
2442     if (s == NULL)
2443       {
2444       expand_string_message = string_sprintf("%s inside \"%s{...}\" condition",
2445         expand_string_message, name);
2446       return NULL;
2447       }
2448     while (isspace(*s)) s++;
2449
2450     if (*s++ != '}')
2451       {
2452       expand_string_message = string_sprintf("missing } at end of condition "
2453         "inside \"%s\" group", name);
2454       return NULL;
2455       }
2456
2457     if (yield != NULL)
2458       {
2459       if (cond_type == ECOND_AND)
2460         {
2461         combined_cond &= tempcond;
2462         if (!combined_cond) subcondptr = NULL;  /* once false, don't */
2463         }                                       /* evaluate any more */
2464       else
2465         {
2466         combined_cond |= tempcond;
2467         if (combined_cond) subcondptr = NULL;   /* once true, don't */
2468         }                                       /* evaluate any more */
2469       }
2470     }
2471
2472   if (yield != NULL) *yield = (combined_cond == testfor);
2473   return ++s;
2474
2475
2476   /* forall/forany: iterates a condition with different values */
2477
2478   case ECOND_FORALL:
2479   case ECOND_FORANY:
2480     {
2481     int sep = 0;
2482     uschar *save_iterate_item = iterate_item;
2483
2484     while (isspace(*s)) s++;
2485     if (*s++ != '{') goto COND_FAILED_CURLY_START;
2486     sub[0] = expand_string_internal(s, TRUE, &s, (yield == NULL), TRUE);
2487     if (sub[0] == NULL) return NULL;
2488     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2489
2490     while (isspace(*s)) s++;
2491     if (*s++ != '{') goto COND_FAILED_CURLY_START;
2492
2493     sub[1] = s;
2494
2495     /* Call eval_condition once, with result discarded (as if scanning a
2496     "false" part). This allows us to find the end of the condition, because if
2497     the list it empty, we won't actually evaluate the condition for real. */
2498
2499     s = eval_condition(sub[1], NULL);
2500     if (s == NULL)
2501       {
2502       expand_string_message = string_sprintf("%s inside \"%s\" condition",
2503         expand_string_message, name);
2504       return NULL;
2505       }
2506     while (isspace(*s)) s++;
2507
2508     if (*s++ != '}')
2509       {
2510       expand_string_message = string_sprintf("missing } at end of condition "
2511         "inside \"%s\"", name);
2512       return NULL;
2513       }
2514
2515     if (yield != NULL) *yield = !testfor;
2516     while ((iterate_item = string_nextinlist(&sub[0], &sep, NULL, 0)) != NULL)
2517       {
2518       DEBUG(D_expand) debug_printf("%s: $item = \"%s\"\n", name, iterate_item);
2519       if (eval_condition(sub[1], &tempcond) == NULL)
2520         {
2521         expand_string_message = string_sprintf("%s inside \"%s\" condition",
2522           expand_string_message, name);
2523         iterate_item = save_iterate_item;
2524         return NULL;
2525         }
2526       DEBUG(D_expand) debug_printf("%s: condition evaluated to %s\n", name,
2527         tempcond? "true":"false");
2528
2529       if (yield != NULL) *yield = (tempcond == testfor);
2530       if (tempcond == (cond_type == ECOND_FORANY)) break;
2531       }
2532
2533     iterate_item = save_iterate_item;
2534     return s;
2535     }
2536
2537
2538   /* The bool{} expansion condition maps a string to boolean.
2539   The values supported should match those supported by the ACL condition
2540   (acl.c, ACLC_CONDITION) so that we keep to a minimum the different ideas
2541   of true/false.  Note that Router "condition" rules have a different
2542   interpretation, where general data can be used and only a few values
2543   map to FALSE.
2544   Note that readconf.c boolean matching, for boolean configuration options,
2545   only matches true/yes/false/no.
2546   The bool_lax{} condition matches the Router logic, which is much more
2547   liberal. */
2548   case ECOND_BOOL:
2549   case ECOND_BOOL_LAX:
2550     {
2551     uschar *sub_arg[1];
2552     uschar *t, *t2;
2553     uschar *ourname;
2554     size_t len;
2555     BOOL boolvalue = FALSE;
2556     while (isspace(*s)) s++;
2557     if (*s != '{') goto COND_FAILED_CURLY_START;
2558     ourname = cond_type == ECOND_BOOL_LAX ? US"bool_lax" : US"bool";
2559     switch(read_subs(sub_arg, 1, 1, &s, yield == NULL, FALSE, ourname))
2560       {
2561       case 1: expand_string_message = string_sprintf(
2562                   "too few arguments or bracketing error for %s",
2563                   ourname);
2564       /*FALLTHROUGH*/
2565       case 2:
2566       case 3: return NULL;
2567       }
2568     t = sub_arg[0];
2569     while (isspace(*t)) t++;
2570     len = Ustrlen(t);
2571     if (len)
2572       {
2573       /* trailing whitespace: seems like a good idea to ignore it too */
2574       t2 = t + len - 1;
2575       while (isspace(*t2)) t2--;
2576       if (t2 != (t + len))
2577         {
2578         *++t2 = '\0';
2579         len = t2 - t;
2580         }
2581       }
2582     DEBUG(D_expand)
2583       debug_printf("considering %s: %s\n", ourname, len ? t : US"<empty>");
2584     /* logic for the lax case from expand_check_condition(), which also does
2585     expands, and the logic is both short and stable enough that there should
2586     be no maintenance burden from replicating it. */
2587     if (len == 0)
2588       boolvalue = FALSE;
2589     else if (Ustrspn(t, "0123456789") == len)
2590       {
2591       boolvalue = (Uatoi(t) == 0) ? FALSE : TRUE;
2592       /* expand_check_condition only does a literal string "0" check */
2593       if ((cond_type == ECOND_BOOL_LAX) && (len > 1))
2594         boolvalue = TRUE;
2595       }
2596     else if (strcmpic(t, US"true") == 0 || strcmpic(t, US"yes") == 0)
2597       boolvalue = TRUE;
2598     else if (strcmpic(t, US"false") == 0 || strcmpic(t, US"no") == 0)
2599       boolvalue = FALSE;
2600     else if (cond_type == ECOND_BOOL_LAX)
2601       boolvalue = TRUE;
2602     else
2603       {
2604       expand_string_message = string_sprintf("unrecognised boolean "
2605        "value \"%s\"", t);
2606       return NULL;
2607       }
2608     if (yield != NULL) *yield = (boolvalue == testfor);
2609     return s;
2610     }
2611
2612   /* Unknown condition */
2613
2614   default:
2615   expand_string_message = string_sprintf("unknown condition \"%s\"", name);
2616   return NULL;
2617   }   /* End switch on condition type */
2618
2619 /* Missing braces at start and end of data */
2620
2621 COND_FAILED_CURLY_START:
2622 expand_string_message = string_sprintf("missing { after \"%s\"", name);
2623 return NULL;
2624
2625 COND_FAILED_CURLY_END:
2626 expand_string_message = string_sprintf("missing } at end of \"%s\" condition",
2627   name);
2628 return NULL;
2629
2630 /* A condition requires code that is not compiled */
2631
2632 #if !defined(SUPPORT_PAM) || !defined(RADIUS_CONFIG_FILE) || \
2633     !defined(LOOKUP_LDAP) || !defined(CYRUS_PWCHECK_SOCKET) || \
2634     !defined(SUPPORT_CRYPTEQ) || !defined(CYRUS_SASLAUTHD_SOCKET)
2635 COND_FAILED_NOT_COMPILED:
2636 expand_string_message = string_sprintf("support for \"%s\" not compiled",
2637   name);
2638 return NULL;
2639 #endif
2640 }
2641
2642
2643
2644
2645 /*************************************************
2646 *          Save numerical variables              *
2647 *************************************************/
2648
2649 /* This function is called from items such as "if" that want to preserve and
2650 restore the numbered variables.
2651
2652 Arguments:
2653   save_expand_string    points to an array of pointers to set
2654   save_expand_nlength   points to an array of ints for the lengths
2655
2656 Returns:                the value of expand max to save
2657 */
2658
2659 static int
2660 save_expand_strings(uschar **save_expand_nstring, int *save_expand_nlength)
2661 {
2662 int i;
2663 for (i = 0; i <= expand_nmax; i++)
2664   {
2665   save_expand_nstring[i] = expand_nstring[i];
2666   save_expand_nlength[i] = expand_nlength[i];
2667   }
2668 return expand_nmax;
2669 }
2670
2671
2672
2673 /*************************************************
2674 *           Restore numerical variables          *
2675 *************************************************/
2676
2677 /* This function restored saved values of numerical strings.
2678
2679 Arguments:
2680   save_expand_nmax      the number of strings to restore
2681   save_expand_string    points to an array of pointers
2682   save_expand_nlength   points to an array of ints
2683
2684 Returns:                nothing
2685 */
2686
2687 static void
2688 restore_expand_strings(int save_expand_nmax, uschar **save_expand_nstring,
2689   int *save_expand_nlength)
2690 {
2691 int i;
2692 expand_nmax = save_expand_nmax;
2693 for (i = 0; i <= expand_nmax; i++)
2694   {
2695   expand_nstring[i] = save_expand_nstring[i];
2696   expand_nlength[i] = save_expand_nlength[i];
2697   }
2698 }
2699
2700
2701
2702
2703
2704 /*************************************************
2705 *            Handle yes/no substrings            *
2706 *************************************************/
2707
2708 /* This function is used by ${if}, ${lookup} and ${extract} to handle the
2709 alternative substrings that depend on whether or not the condition was true,
2710 or the lookup or extraction succeeded. The substrings always have to be
2711 expanded, to check their syntax, but "skipping" is set when the result is not
2712 needed - this avoids unnecessary nested lookups.
2713
2714 Arguments:
2715   skipping       TRUE if we were skipping when this item was reached
2716   yes            TRUE if the first string is to be used, else use the second
2717   save_lookup    a value to put back into lookup_value before the 2nd expansion
2718   sptr           points to the input string pointer
2719   yieldptr       points to the output string pointer
2720   sizeptr        points to the output string size
2721   ptrptr         points to the output string pointer
2722   type           "lookup" or "if" or "extract" or "run", for error message
2723
2724 Returns:         0 OK; lookup_value has been reset to save_lookup
2725                  1 expansion failed
2726                  2 expansion failed because of bracketing error
2727 */
2728
2729 static int
2730 process_yesno(BOOL skipping, BOOL yes, uschar *save_lookup, uschar **sptr,
2731   uschar **yieldptr, int *sizeptr, int *ptrptr, uschar *type)
2732 {
2733 int rc = 0;
2734 uschar *s = *sptr;    /* Local value */
2735 uschar *sub1, *sub2;
2736
2737 /* If there are no following strings, we substitute the contents of $value for
2738 lookups and for extractions in the success case. For the ${if item, the string
2739 "true" is substituted. In the fail case, nothing is substituted for all three
2740 items. */
2741
2742 while (isspace(*s)) s++;
2743 if (*s == '}')
2744   {
2745   if (type[0] == 'i')
2746     {
2747     if (yes) *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, US"true", 4);
2748     }
2749   else
2750     {
2751     if (yes && lookup_value != NULL)
2752       *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, lookup_value,
2753         Ustrlen(lookup_value));
2754     lookup_value = save_lookup;
2755     }
2756   s++;
2757   goto RETURN;
2758   }
2759
2760 /* The first following string must be braced. */
2761
2762 if (*s++ != '{') goto FAILED_CURLY;
2763
2764 /* Expand the first substring. Forced failures are noticed only if we actually
2765 want this string. Set skipping in the call in the fail case (this will always
2766 be the case if we were already skipping). */
2767
2768 sub1 = expand_string_internal(s, TRUE, &s, !yes, TRUE);
2769 if (sub1 == NULL && (yes || !expand_string_forcedfail)) goto FAILED;
2770 expand_string_forcedfail = FALSE;
2771 if (*s++ != '}') goto FAILED_CURLY;
2772
2773 /* If we want the first string, add it to the output */
2774
2775 if (yes)
2776   *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, sub1, Ustrlen(sub1));
2777
2778 /* If this is called from a lookup or an extract, we want to restore $value to
2779 what it was at the start of the item, so that it has this value during the
2780 second string expansion. For the call from "if" or "run" to this function,
2781 save_lookup is set to lookup_value, so that this statement does nothing. */
2782
2783 lookup_value = save_lookup;
2784
2785 /* There now follows either another substring, or "fail", or nothing. This
2786 time, forced failures are noticed only if we want the second string. We must
2787 set skipping in the nested call if we don't want this string, or if we were
2788 already skipping. */
2789
2790 while (isspace(*s)) s++;
2791 if (*s == '{')
2792   {
2793   sub2 = expand_string_internal(s+1, TRUE, &s, yes || skipping, TRUE);
2794   if (sub2 == NULL && (!yes || !expand_string_forcedfail)) goto FAILED;
2795   expand_string_forcedfail = FALSE;
2796   if (*s++ != '}') goto FAILED_CURLY;
2797
2798   /* If we want the second string, add it to the output */
2799
2800   if (!yes)
2801     *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, sub2, Ustrlen(sub2));
2802   }
2803
2804 /* If there is no second string, but the word "fail" is present when the use of
2805 the second string is wanted, set a flag indicating it was a forced failure
2806 rather than a syntactic error. Swallow the terminating } in case this is nested
2807 inside another lookup or if or extract. */
2808
2809 else if (*s != '}')
2810   {
2811   uschar name[256];
2812   s = read_name(name, sizeof(name), s, US"_");
2813   if (Ustrcmp(name, "fail") == 0)
2814     {
2815     if (!yes && !skipping)
2816       {
2817       while (isspace(*s)) s++;
2818       if (*s++ != '}') goto FAILED_CURLY;
2819       expand_string_message =
2820         string_sprintf("\"%s\" failed and \"fail\" requested", type);
2821       expand_string_forcedfail = TRUE;
2822       goto FAILED;
2823       }
2824     }
2825   else
2826     {
2827     expand_string_message =
2828       string_sprintf("syntax error in \"%s\" item - \"fail\" expected", type);
2829     goto FAILED;
2830     }
2831   }
2832
2833 /* All we have to do now is to check on the final closing brace. */
2834
2835 while (isspace(*s)) s++;
2836 if (*s++ == '}') goto RETURN;
2837
2838 /* Get here if there is a bracketing failure */
2839
2840 FAILED_CURLY:
2841 rc++;
2842
2843 /* Get here for other failures */
2844
2845 FAILED:
2846 rc++;
2847
2848 /* Update the input pointer value before returning */
2849
2850 RETURN:
2851 *sptr = s;
2852 return rc;
2853 }
2854
2855
2856
2857
2858 /*************************************************
2859 *    Handle MD5 or SHA-1 computation for HMAC    *
2860 *************************************************/
2861
2862 /* These are some wrapping functions that enable the HMAC code to be a bit
2863 cleaner. A good compiler will spot the tail recursion.
2864
2865 Arguments:
2866   type         HMAC_MD5 or HMAC_SHA1
2867   remaining    are as for the cryptographic hash functions
2868
2869 Returns:       nothing
2870 */
2871
2872 static void
2873 chash_start(int type, void *base)
2874 {
2875 if (type == HMAC_MD5)
2876   md5_start((md5 *)base);
2877 else
2878   sha1_start((sha1 *)base);
2879 }
2880
2881 static void
2882 chash_mid(int type, void *base, uschar *string)
2883 {
2884 if (type == HMAC_MD5)
2885   md5_mid((md5 *)base, string);
2886 else
2887   sha1_mid((sha1 *)base, string);
2888 }
2889
2890 static void
2891 chash_end(int type, void *base, uschar *string, int length, uschar *digest)
2892 {
2893 if (type == HMAC_MD5)
2894   md5_end((md5 *)base, string, length, digest);
2895 else
2896   sha1_end((sha1 *)base, string, length, digest);
2897 }
2898
2899
2900
2901
2902
2903 /********************************************************
2904 * prvs: Get last three digits of days since Jan 1, 1970 *
2905 ********************************************************/
2906
2907 /* This is needed to implement the "prvs" BATV reverse
2908    path signing scheme
2909
2910 Argument: integer "days" offset to add or substract to
2911           or from the current number of days.
2912
2913 Returns:  pointer to string containing the last three
2914           digits of the number of days since Jan 1, 1970,
2915           modified by the offset argument, NULL if there
2916           was an error in the conversion.
2917
2918 */
2919
2920 static uschar *
2921 prvs_daystamp(int day_offset)
2922 {
2923 uschar *days = store_get(32);                /* Need at least 24 for cases */
2924 (void)string_format(days, 32, TIME_T_FMT,    /* where TIME_T_FMT is %lld */
2925   (time(NULL) + day_offset*86400)/86400);
2926 return (Ustrlen(days) >= 3) ? &days[Ustrlen(days)-3] : US"100";
2927 }
2928
2929
2930
2931 /********************************************************
2932 *   prvs: perform HMAC-SHA1 computation of prvs bits    *
2933 ********************************************************/
2934
2935 /* This is needed to implement the "prvs" BATV reverse
2936    path signing scheme
2937
2938 Arguments:
2939   address RFC2821 Address to use
2940       key The key to use (must be less than 64 characters
2941           in size)
2942   key_num Single-digit key number to use. Defaults to
2943           '0' when NULL.
2944
2945 Returns:  pointer to string containing the first three
2946           bytes of the final hash in hex format, NULL if
2947           there was an error in the process.
2948 */
2949
2950 static uschar *
2951 prvs_hmac_sha1(uschar *address, uschar *key, uschar *key_num, uschar *daystamp)
2952 {
2953 uschar *hash_source, *p;
2954 int size = 0,offset = 0,i;
2955 sha1 sha1_base;
2956 void *use_base = &sha1_base;
2957 uschar innerhash[20];
2958 uschar finalhash[20];
2959 uschar innerkey[64];
2960 uschar outerkey[64];
2961 uschar *finalhash_hex = store_get(40);
2962
2963 if (key_num == NULL)
2964   key_num = US"0";
2965
2966 if (Ustrlen(key) > 64)
2967   return NULL;
2968
2969 hash_source = string_cat(NULL,&size,&offset,key_num,1);
2970 string_cat(hash_source,&size,&offset,daystamp,3);
2971 string_cat(hash_source,&size,&offset,address,Ustrlen(address));
2972 hash_source[offset] = '\0';
2973
2974 DEBUG(D_expand) debug_printf("prvs: hash source is '%s'\n", hash_source);
2975
2976 memset(innerkey, 0x36, 64);
2977 memset(outerkey, 0x5c, 64);
2978
2979 for (i = 0; i < Ustrlen(key); i++)
2980   {
2981   innerkey[i] ^= key[i];
2982   outerkey[i] ^= key[i];
2983   }
2984
2985 chash_start(HMAC_SHA1, use_base);
2986 chash_mid(HMAC_SHA1, use_base, innerkey);
2987 chash_end(HMAC_SHA1, use_base, hash_source, offset, innerhash);
2988
2989 chash_start(HMAC_SHA1, use_base);
2990 chash_mid(HMAC_SHA1, use_base, outerkey);
2991 chash_end(HMAC_SHA1, use_base, innerhash, 20, finalhash);
2992
2993 p = finalhash_hex;
2994 for (i = 0; i < 3; i++)
2995   {
2996   *p++ = hex_digits[(finalhash[i] & 0xf0) >> 4];
2997   *p++ = hex_digits[finalhash[i] & 0x0f];
2998   }
2999 *p = '\0';
3000
3001 return finalhash_hex;
3002 }
3003
3004
3005
3006
3007 /*************************************************
3008 *        Join a file onto the output string      *
3009 *************************************************/
3010
3011 /* This is used for readfile and after a run expansion. It joins the contents
3012 of a file onto the output string, globally replacing newlines with a given
3013 string (optionally). The file is closed at the end.
3014
3015 Arguments:
3016   f            the FILE
3017   yield        pointer to the expandable string
3018   sizep        pointer to the current size
3019   ptrp         pointer to the current position
3020   eol          newline replacement string, or NULL
3021
3022 Returns:       new value of string pointer
3023 */
3024
3025 static uschar *
3026 cat_file(FILE *f, uschar *yield, int *sizep, int *ptrp, uschar *eol)
3027 {
3028 int eollen;
3029 uschar buffer[1024];
3030
3031 eollen = (eol == NULL)? 0 : Ustrlen(eol);
3032
3033 while (Ufgets(buffer, sizeof(buffer), f) != NULL)
3034   {
3035   int len = Ustrlen(buffer);
3036   if (eol != NULL && buffer[len-1] == '\n') len--;
3037   yield = string_cat(yield, sizep, ptrp, buffer, len);
3038   if (buffer[len] != 0)
3039     yield = string_cat(yield, sizep, ptrp, eol, eollen);
3040   }
3041
3042 if (yield != NULL) yield[*ptrp] = 0;
3043
3044 return yield;
3045 }
3046
3047
3048
3049
3050 /*************************************************
3051 *          Evaluate numeric expression           *
3052 *************************************************/
3053
3054 /* This is a set of mutually recursive functions that evaluate an arithmetic
3055 expression involving + - * / % & | ^ ~ << >> and parentheses. The only one of
3056 these functions that is called from elsewhere is eval_expr, whose interface is:
3057
3058 Arguments:
3059   sptr        pointer to the pointer to the string - gets updated
3060   decimal     TRUE if numbers are to be assumed decimal
3061   error       pointer to where to put an error message - must be NULL on input
3062   endket      TRUE if ')' must terminate - FALSE for external call
3063
3064 Returns:      on success: the value of the expression, with *error still NULL
3065               on failure: an undefined value, with *error = a message
3066 */
3067
3068 static int eval_op_or(uschar **, BOOL, uschar **);
3069
3070
3071 static int
3072 eval_expr(uschar **sptr, BOOL decimal, uschar **error, BOOL endket)
3073 {
3074 uschar *s = *sptr;
3075 int x = eval_op_or(&s, decimal, error);
3076 if (*error == NULL)
3077   {
3078   if (endket)
3079     {
3080     if (*s != ')')
3081       *error = US"expecting closing parenthesis";
3082     else
3083       while (isspace(*(++s)));
3084     }
3085   else if (*s != 0) *error = US"expecting operator";
3086   }
3087 *sptr = s;
3088 return x;
3089 }
3090
3091
3092 static int
3093 eval_number(uschar **sptr, BOOL decimal, uschar **error)
3094 {
3095 register int c;
3096 int n;
3097 uschar *s = *sptr;
3098 while (isspace(*s)) s++;
3099 c = *s;
3100 if (isdigit(c))
3101   {
3102   int count;
3103   (void)sscanf(CS s, (decimal? "%d%n" : "%i%n"), &n, &count);
3104   s += count;
3105   if (tolower(*s) == 'k') { n *= 1024; s++; }
3106     else if (tolower(*s) == 'm') { n *= 1024*1024; s++; }
3107   while (isspace (*s)) s++;
3108   }
3109 else if (c == '(')
3110   {
3111   s++;
3112   n = eval_expr(&s, decimal, error, 1);
3113   }
3114 else
3115   {
3116   *error = US"expecting number or opening parenthesis";
3117   n = 0;
3118   }
3119 *sptr = s;
3120 return n;
3121 }
3122
3123
3124 static int eval_op_unary(uschar **sptr, BOOL decimal, uschar **error)
3125 {
3126 uschar *s = *sptr;
3127 int x;
3128 while (isspace(*s)) s++;
3129 if (*s == '+' || *s == '-' || *s == '~')
3130   {
3131   int op = *s++;
3132   x = eval_op_unary(&s, decimal, error);
3133   if (op == '-') x = -x;
3134     else if (op == '~') x = ~x;
3135   }
3136 else
3137   {
3138   x = eval_number(&s, decimal, error);
3139   }
3140 *sptr = s;
3141 return x;
3142 }
3143
3144
3145 static int eval_op_mult(uschar **sptr, BOOL decimal, uschar **error)
3146 {
3147 uschar *s = *sptr;
3148 int x = eval_op_unary(&s, decimal, error);
3149 if (*error == NULL)
3150   {
3151   while (*s == '*' || *s == '/' || *s == '%')
3152     {
3153     int op = *s++;
3154     int y = eval_op_unary(&s, decimal, error);
3155     if (*error != NULL) break;
3156     /* SIGFPE both on div/mod by zero and on INT_MIN / -1, which would give
3157      * a value of INT_MAX+1. Note that INT_MIN * -1 gives INT_MIN for me, which
3158      * is a bug somewhere in [gcc 4.2.1, FreeBSD, amd64].  In fact, -N*-M where
3159      * -N*M is INT_MIN will yielf INT_MIN.
3160      * Since we don't support floating point, this is somewhat simpler.
3161      * Ideally, we'd return an error, but since we overflow for all other
3162      * arithmetic, consistency suggests otherwise, but what's the correct value
3163      * to use?  There is none.
3164      * The C standard guarantees overflow for unsigned arithmetic but signed
3165      * overflow invokes undefined behaviour; in practice, this is overflow
3166      * except for converting INT_MIN to INT_MAX+1.  We also can't guarantee
3167      * that long/longlong larger than int are available, or we could just work
3168      * with larger types.  We should consider whether to guarantee 32bit eval
3169      * and 64-bit working variables, with errors returned.  For now ...
3170      * So, the only SIGFPEs occur with a non-shrinking div/mod, thus -1; we
3171      * can just let the other invalid results occur otherwise, as they have
3172      * until now.  For this one case, we can coerce.
3173      */
3174     if (y == -1 && x == INT_MIN && op != '*')
3175       {
3176       DEBUG(D_expand)
3177         debug_printf("Integer exception dodging: %d%c-1 coerced to %d\n",
3178             INT_MIN, op, INT_MAX);
3179       x = INT_MAX;
3180       continue;
3181       }
3182     if (op == '*')
3183       x *= y;
3184     else
3185       {
3186       if (y == 0)
3187         {
3188         *error = (op == '/') ? US"divide by zero" : US"modulo by zero";
3189         x = 0;
3190         break;
3191         }
3192       if (op == '/')
3193         x /= y;
3194       else
3195         x %= y;
3196       }
3197     }
3198   }
3199 *sptr = s;
3200 return x;
3201 }
3202
3203
3204 static int eval_op_sum(uschar **sptr, BOOL decimal, uschar **error)
3205 {
3206 uschar *s = *sptr;
3207 int x = eval_op_mult(&s, decimal, error);
3208 if (*error == NULL)
3209   {
3210   while (*s == '+' || *s == '-')
3211     {
3212     int op = *s++;
3213     int y = eval_op_mult(&s, decimal, error);
3214     if (*error != NULL) break;
3215     if (op == '+') x += y; else x -= y;
3216     }
3217   }
3218 *sptr = s;
3219 return x;
3220 }
3221
3222
3223 static int eval_op_shift(uschar **sptr, BOOL decimal, uschar **error)
3224 {
3225 uschar *s = *sptr;
3226 int x = eval_op_sum(&s, decimal, error);
3227 if (*error == NULL)
3228   {
3229   while ((*s == '<' || *s == '>') && s[1] == s[0])
3230     {
3231     int y;
3232     int op = *s++;
3233     s++;
3234     y = eval_op_sum(&s, decimal, error);
3235     if (*error != NULL) break;
3236     if (op == '<') x <<= y; else x >>= y;
3237     }
3238   }
3239 *sptr = s;
3240 return x;
3241 }
3242
3243
3244 static int eval_op_and(uschar **sptr, BOOL decimal, uschar **error)
3245 {
3246 uschar *s = *sptr;
3247 int x = eval_op_shift(&s, decimal, error);
3248 if (*error == NULL)
3249   {
3250   while (*s == '&')
3251     {
3252     int y;
3253     s++;
3254     y = eval_op_shift(&s, decimal, error);
3255     if (*error != NULL) break;
3256     x &= y;
3257     }
3258   }
3259 *sptr = s;
3260 return x;
3261 }
3262
3263
3264 static int eval_op_xor(uschar **sptr, BOOL decimal, uschar **error)
3265 {
3266 uschar *s = *sptr;
3267 int x = eval_op_and(&s, decimal, error);
3268 if (*error == NULL)
3269   {
3270   while (*s == '^')
3271     {
3272     int y;
3273     s++;
3274     y = eval_op_and(&s, decimal, error);
3275     if (*error != NULL) break;
3276     x ^= y;
3277     }
3278   }
3279 *sptr = s;
3280 return x;
3281 }
3282
3283
3284 static int eval_op_or(uschar **sptr, BOOL decimal, uschar **error)
3285 {
3286 uschar *s = *sptr;
3287 int x = eval_op_xor(&s, decimal, error);
3288 if (*error == NULL)
3289   {
3290   while (*s == '|')
3291     {
3292     int y;
3293     s++;
3294     y = eval_op_xor(&s, decimal, error);
3295     if (*error != NULL) break;
3296     x |= y;
3297     }
3298   }
3299 *sptr = s;
3300 return x;
3301 }
3302
3303
3304
3305 /*************************************************
3306 *                 Expand string                  *
3307 *************************************************/
3308
3309 /* Returns either an unchanged string, or the expanded string in stacking pool
3310 store. Interpreted sequences are:
3311
3312    \...                    normal escaping rules
3313    $name                   substitutes the variable
3314    ${name}                 ditto
3315    ${op:string}            operates on the expanded string value
3316    ${item{arg1}{arg2}...}  expands the args and then does the business
3317                              some literal args are not enclosed in {}
3318
3319 There are now far too many operators and item types to make it worth listing
3320 them here in detail any more.
3321
3322 We use an internal routine recursively to handle embedded substrings. The
3323 external function follows. The yield is NULL if the expansion failed, and there
3324 are two cases: if something collapsed syntactically, or if "fail" was given
3325 as the action on a lookup failure. These can be distinguised by looking at the
3326 variable expand_string_forcedfail, which is TRUE in the latter case.
3327
3328 The skipping flag is set true when expanding a substring that isn't actually
3329 going to be used (after "if" or "lookup") and it prevents lookups from
3330 happening lower down.
3331
3332 Store usage: At start, a store block of the length of the input plus 64
3333 is obtained. This is expanded as necessary by string_cat(), which might have to
3334 get a new block, or might be able to expand the original. At the end of the
3335 function we can release any store above that portion of the yield block that
3336 was actually used. In many cases this will be optimal.
3337
3338 However: if the first item in the expansion is a variable name or header name,
3339 we reset the store before processing it; if the result is in fresh store, we
3340 use that without copying. This is helpful for expanding strings like
3341 $message_headers which can get very long.
3342
3343 There's a problem if a ${dlfunc item has side-effects that cause allocation,
3344 since resetting the store at the end of the expansion will free store that was
3345 allocated by the plugin code as well as the slop after the expanded string. So
3346 we skip any resets if ${dlfunc has been used. This is an unfortunate
3347 consequence of string expansion becoming too powerful.
3348
3349 Arguments:
3350   string         the string to be expanded
3351   ket_ends       true if expansion is to stop at }
3352   left           if not NULL, a pointer to the first character after the
3353                  expansion is placed here (typically used with ket_ends)
3354   skipping       TRUE for recursive calls when the value isn't actually going
3355                  to be used (to allow for optimisation)
3356   honour_dollar  TRUE if $ is to be expanded,
3357                  FALSE if it's just another character
3358
3359 Returns:         NULL if expansion fails:
3360                    expand_string_forcedfail is set TRUE if failure was forced
3361                    expand_string_message contains a textual error message
3362                  a pointer to the expanded string on success
3363 */
3364
3365 static uschar *
3366 expand_string_internal(uschar *string, BOOL ket_ends, uschar **left,
3367   BOOL skipping, BOOL honour_dollar)
3368 {
3369 int ptr = 0;
3370 int size = Ustrlen(string)+ 64;
3371 int item_type;
3372 uschar *yield = store_get(size);
3373 uschar *s = string;
3374 uschar *save_expand_nstring[EXPAND_MAXN+1];
3375 int save_expand_nlength[EXPAND_MAXN+1];
3376 BOOL resetok = TRUE;
3377
3378 expand_string_forcedfail = FALSE;
3379 expand_string_message = US"";
3380
3381 while (*s != 0)
3382   {
3383   uschar *value;
3384   uschar name[256];
3385
3386   /* \ escapes the next character, which must exist, or else
3387   the expansion fails. There's a special escape, \N, which causes
3388   copying of the subject verbatim up to the next \N. Otherwise,
3389   the escapes are the standard set. */
3390
3391   if (*s == '\\')
3392     {
3393     if (s[1] == 0)
3394       {
3395       expand_string_message = US"\\ at end of string";
3396       goto EXPAND_FAILED;
3397       }
3398
3399     if (s[1] == 'N')
3400       {
3401       uschar *t = s + 2;
3402       for (s = t; *s != 0; s++) if (*s == '\\' && s[1] == 'N') break;
3403       yield = string_cat(yield, &size, &ptr, t, s - t);
3404       if (*s != 0) s += 2;
3405       }
3406
3407     else
3408       {
3409       uschar ch[1];
3410       ch[0] = string_interpret_escape(&s);
3411       s++;
3412       yield = string_cat(yield, &size, &ptr, ch, 1);
3413       }
3414
3415     continue;
3416     }
3417
3418   /* Anything other than $ is just copied verbatim, unless we are
3419   looking for a terminating } character. */
3420
3421   if (ket_ends && *s == '}') break;
3422
3423   if (*s != '$' || !honour_dollar)
3424     {
3425     yield = string_cat(yield, &size, &ptr, s++, 1);
3426     continue;
3427     }
3428
3429   /* No { after the $ - must be a plain name or a number for string
3430   match variable. There has to be a fudge for variables that are the
3431   names of header fields preceded by "$header_" because header field
3432   names can contain any printing characters except space and colon.
3433   For those that don't like typing this much, "$h_" is a synonym for
3434   "$header_". A non-existent header yields a NULL value; nothing is
3435   inserted. */
3436
3437   if (isalpha((*(++s))))
3438     {
3439     int len;
3440     int newsize = 0;
3441
3442     s = read_name(name, sizeof(name), s, US"_");
3443
3444     /* If this is the first thing to be expanded, release the pre-allocated
3445     buffer. */
3446
3447     if (ptr == 0 && yield != NULL)
3448       {
3449       if (resetok) store_reset(yield);
3450       yield = NULL;
3451       size = 0;
3452       }
3453
3454     /* Header */
3455
3456     if (Ustrncmp(name, "h_", 2) == 0 ||
3457         Ustrncmp(name, "rh_", 3) == 0 ||
3458         Ustrncmp(name, "bh_", 3) == 0 ||
3459         Ustrncmp(name, "header_", 7) == 0 ||
3460         Ustrncmp(name, "rheader_", 8) == 0 ||
3461         Ustrncmp(name, "bheader_", 8) == 0)
3462       {
3463       BOOL want_raw = (name[0] == 'r')? TRUE : FALSE;
3464       uschar *charset = (name[0] == 'b')? NULL : headers_charset;
3465       s = read_header_name(name, sizeof(name), s);
3466       value = find_header(name, FALSE, &newsize, want_raw, charset);
3467
3468       /* If we didn't find the header, and the header contains a closing brace
3469       character, this may be a user error where the terminating colon
3470       has been omitted. Set a flag to adjust the error message in this case.
3471       But there is no error here - nothing gets inserted. */
3472
3473       if (value == NULL)
3474         {
3475         if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
3476         continue;
3477         }
3478       }
3479
3480     /* Variable */
3481
3482     else
3483       {
3484       value = find_variable(name, FALSE, skipping, &newsize);
3485       if (value == NULL)
3486         {
3487         expand_string_message =
3488           string_sprintf("unknown variable name \"%s\"", name);
3489           check_variable_error_message(name);
3490         goto EXPAND_FAILED;
3491         }
3492       }
3493
3494     /* If the data is known to be in a new buffer, newsize will be set to the
3495     size of that buffer. If this is the first thing in an expansion string,
3496     yield will be NULL; just point it at the new store instead of copying. Many
3497     expansion strings contain just one reference, so this is a useful
3498     optimization, especially for humungous headers. */
3499
3500     len = Ustrlen(value);
3501     if (yield == NULL && newsize != 0)
3502       {
3503       yield = value;
3504       size = newsize;
3505       ptr = len;
3506       }
3507     else yield = string_cat(yield, &size, &ptr, value, len);
3508
3509     continue;
3510     }
3511
3512   if (isdigit(*s))
3513     {
3514     int n;
3515     s = read_number(&n, s);
3516     if (n >= 0 && n <= expand_nmax)
3517       yield = string_cat(yield, &size, &ptr, expand_nstring[n],
3518         expand_nlength[n]);
3519     continue;
3520     }
3521
3522   /* Otherwise, if there's no '{' after $ it's an error. */
3523
3524   if (*s != '{')
3525     {
3526     expand_string_message = US"$ not followed by letter, digit, or {";
3527     goto EXPAND_FAILED;
3528     }
3529
3530   /* After { there can be various things, but they all start with
3531   an initial word, except for a number for a string match variable. */
3532
3533   if (isdigit((*(++s))))
3534     {
3535     int n;
3536     s = read_number(&n, s);
3537     if (*s++ != '}')
3538       {
3539       expand_string_message = US"} expected after number";
3540       goto EXPAND_FAILED;
3541       }
3542     if (n >= 0 && n <= expand_nmax)
3543       yield = string_cat(yield, &size, &ptr, expand_nstring[n],
3544         expand_nlength[n]);
3545     continue;
3546     }
3547
3548   if (!isalpha(*s))
3549     {
3550     expand_string_message = US"letter or digit expected after ${";
3551     goto EXPAND_FAILED;
3552     }
3553
3554   /* Allow "-" in names to cater for substrings with negative
3555   arguments. Since we are checking for known names after { this is
3556   OK. */
3557
3558   s = read_name(name, sizeof(name), s, US"_-");
3559   item_type = chop_match(name, item_table, sizeof(item_table)/sizeof(uschar *));
3560
3561   switch(item_type)
3562     {
3563     /* Handle conditionals - preserve the values of the numerical expansion
3564     variables in case they get changed by a regular expression match in the
3565     condition. If not, they retain their external settings. At the end
3566     of this "if" section, they get restored to their previous values. */
3567
3568     case EITEM_IF:
3569       {
3570       BOOL cond = FALSE;
3571       uschar *next_s;
3572       int save_expand_nmax =
3573         save_expand_strings(save_expand_nstring, save_expand_nlength);
3574
3575       while (isspace(*s)) s++;
3576       next_s = eval_condition(s, skipping? NULL : &cond);
3577       if (next_s == NULL) goto EXPAND_FAILED;  /* message already set */
3578
3579       DEBUG(D_expand)
3580         debug_printf("condition: %.*s\n   result: %s\n", (int)(next_s - s), s,
3581           cond? "true" : "false");
3582
3583       s = next_s;
3584
3585       /* The handling of "yes" and "no" result strings is now in a separate
3586       function that is also used by ${lookup} and ${extract} and ${run}. */
3587
3588       switch(process_yesno(
3589                skipping,                     /* were previously skipping */
3590                cond,                         /* success/failure indicator */
3591                lookup_value,                 /* value to reset for string2 */
3592                &s,                           /* input pointer */
3593                &yield,                       /* output pointer */
3594                &size,                        /* output size */
3595                &ptr,                         /* output current point */
3596                US"if"))                      /* condition type */
3597         {
3598         case 1: goto EXPAND_FAILED;          /* when all is well, the */
3599         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
3600         }
3601
3602       /* Restore external setting of expansion variables for continuation
3603       at this level. */
3604
3605       restore_expand_strings(save_expand_nmax, save_expand_nstring,
3606         save_expand_nlength);
3607       continue;
3608       }
3609
3610     /* Handle database lookups unless locked out. If "skipping" is TRUE, we are
3611     expanding an internal string that isn't actually going to be used. All we
3612     need to do is check the syntax, so don't do a lookup at all. Preserve the
3613     values of the numerical expansion variables in case they get changed by a
3614     partial lookup. If not, they retain their external settings. At the end
3615     of this "lookup" section, they get restored to their previous values. */
3616
3617     case EITEM_LOOKUP:
3618       {
3619       int stype, partial, affixlen, starflags;
3620       int expand_setup = 0;
3621       int nameptr = 0;
3622       uschar *key, *filename, *affix;
3623       uschar *save_lookup_value = lookup_value;
3624       int save_expand_nmax =
3625         save_expand_strings(save_expand_nstring, save_expand_nlength);
3626
3627       if ((expand_forbid & RDO_LOOKUP) != 0)
3628         {
3629         expand_string_message = US"lookup expansions are not permitted";
3630         goto EXPAND_FAILED;
3631         }
3632
3633       /* Get the key we are to look up for single-key+file style lookups.
3634       Otherwise set the key NULL pro-tem. */
3635
3636       while (isspace(*s)) s++;
3637       if (*s == '{')
3638         {
3639         key = expand_string_internal(s+1, TRUE, &s, skipping, TRUE);
3640         if (key == NULL) goto EXPAND_FAILED;
3641         if (*s++ != '}') goto EXPAND_FAILED_CURLY;
3642         while (isspace(*s)) s++;
3643         }
3644       else key = NULL;
3645
3646       /* Find out the type of database */
3647
3648       if (!isalpha(*s))
3649         {
3650         expand_string_message = US"missing lookup type";
3651         goto EXPAND_FAILED;
3652         }
3653
3654       /* The type is a string that may contain special characters of various
3655       kinds. Allow everything except space or { to appear; the actual content
3656       is checked by search_findtype_partial. */
3657
3658       while (*s != 0 && *s != '{' && !isspace(*s))
3659         {
3660         if (nameptr < sizeof(name) - 1) name[nameptr++] = *s;
3661         s++;
3662         }
3663       name[nameptr] = 0;
3664       while (isspace(*s)) s++;
3665
3666       /* Now check for the individual search type and any partial or default
3667       options. Only those types that are actually in the binary are valid. */
3668
3669       stype = search_findtype_partial(name, &partial, &affix, &affixlen,
3670         &starflags);
3671       if (stype < 0)
3672         {
3673         expand_string_message = search_error_message;
3674         goto EXPAND_FAILED;
3675         }
3676
3677       /* Check that a key was provided for those lookup types that need it,
3678       and was not supplied for those that use the query style. */
3679
3680       if (!mac_islookup(stype, lookup_querystyle|lookup_absfilequery))
3681         {
3682         if (key == NULL)
3683           {
3684           expand_string_message = string_sprintf("missing {key} for single-"
3685             "key \"%s\" lookup", name);
3686           goto EXPAND_FAILED;
3687           }
3688         }
3689       else
3690         {
3691         if (key != NULL)
3692           {
3693           expand_string_message = string_sprintf("a single key was given for "
3694             "lookup type \"%s\", which is not a single-key lookup type", name);
3695           goto EXPAND_FAILED;
3696           }
3697         }
3698
3699       /* Get the next string in brackets and expand it. It is the file name for
3700       single-key+file lookups, and the whole query otherwise. In the case of
3701       queries that also require a file name (e.g. sqlite), the file name comes
3702       first. */
3703
3704       if (*s != '{') goto EXPAND_FAILED_CURLY;
3705       filename = expand_string_internal(s+1, TRUE, &s, skipping, TRUE);
3706       if (filename == NULL) goto EXPAND_FAILED;
3707       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
3708       while (isspace(*s)) s++;
3709
3710       /* If this isn't a single-key+file lookup, re-arrange the variables
3711       to be appropriate for the search_ functions. For query-style lookups,
3712       there is just a "key", and no file name. For the special query-style +
3713       file types, the query (i.e. "key") starts with a file name. */
3714
3715       if (key == NULL)
3716         {
3717         while (isspace(*filename)) filename++;
3718         key = filename;
3719
3720         if (mac_islookup(stype, lookup_querystyle))
3721           {
3722           filename = NULL;
3723           }
3724         else
3725           {
3726           if (*filename != '/')
3727             {
3728             expand_string_message = string_sprintf(
3729               "absolute file name expected for \"%s\" lookup", name);
3730             goto EXPAND_FAILED;
3731             }
3732           while (*key != 0 && !isspace(*key)) key++;
3733           if (*key != 0) *key++ = 0;
3734           }
3735         }
3736
3737       /* If skipping, don't do the next bit - just lookup_value == NULL, as if
3738       the entry was not found. Note that there is no search_close() function.
3739       Files are left open in case of re-use. At suitable places in higher logic,
3740       search_tidyup() is called to tidy all open files. This can save opening
3741       the same file several times. However, files may also get closed when
3742       others are opened, if too many are open at once. The rule is that a
3743       handle should not be used after a second search_open().
3744
3745       Request that a partial search sets up $1 and maybe $2 by passing
3746       expand_setup containing zero. If its value changes, reset expand_nmax,
3747       since new variables will have been set. Note that at the end of this
3748       "lookup" section, the old numeric variables are restored. */
3749
3750       if (skipping)
3751         lookup_value = NULL;
3752       else
3753         {
3754         void *handle = search_open(filename, stype, 0, NULL, NULL);
3755         if (handle == NULL)
3756           {
3757           expand_string_message = search_error_message;
3758           goto EXPAND_FAILED;
3759           }
3760         lookup_value = search_find(handle, filename, key, partial, affix,
3761           affixlen, starflags, &expand_setup);
3762         if (search_find_defer)
3763           {
3764           expand_string_message =
3765             string_sprintf("lookup of \"%s\" gave DEFER: %s",
3766               string_printing2(key, FALSE), search_error_message);
3767           goto EXPAND_FAILED;
3768           }
3769         if (expand_setup > 0) expand_nmax = expand_setup;
3770         }
3771
3772       /* The handling of "yes" and "no" result strings is now in a separate
3773       function that is also used by ${if} and ${extract}. */
3774
3775       switch(process_yesno(
3776                skipping,                     /* were previously skipping */
3777                lookup_value != NULL,         /* success/failure indicator */
3778                save_lookup_value,            /* value to reset for string2 */
3779                &s,                           /* input pointer */
3780                &yield,                       /* output pointer */
3781                &size,                        /* output size */
3782                &ptr,                         /* output current point */
3783                US"lookup"))                  /* condition type */
3784         {
3785         case 1: goto EXPAND_FAILED;          /* when all is well, the */
3786         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
3787         }
3788
3789       /* Restore external setting of expansion variables for carrying on
3790       at this level, and continue. */
3791
3792       restore_expand_strings(save_expand_nmax, save_expand_nstring,
3793         save_expand_nlength);
3794       continue;
3795       }
3796
3797     /* If Perl support is configured, handle calling embedded perl subroutines,
3798     unless locked out at this time. Syntax is ${perl{sub}} or ${perl{sub}{arg}}
3799     or ${perl{sub}{arg1}{arg2}} or up to a maximum of EXIM_PERL_MAX_ARGS
3800     arguments (defined below). */
3801
3802     #define EXIM_PERL_MAX_ARGS 8
3803
3804     case EITEM_PERL:
3805     #ifndef EXIM_PERL
3806     expand_string_message = US"\"${perl\" encountered, but this facility "
3807       "is not included in this binary";
3808     goto EXPAND_FAILED;
3809
3810     #else   /* EXIM_PERL */
3811       {
3812       uschar *sub_arg[EXIM_PERL_MAX_ARGS + 2];
3813       uschar *new_yield;
3814
3815       if ((expand_forbid & RDO_PERL) != 0)
3816         {
3817         expand_string_message = US"Perl calls are not permitted";
3818         goto EXPAND_FAILED;
3819         }
3820
3821       switch(read_subs(sub_arg, EXIM_PERL_MAX_ARGS + 1, 1, &s, skipping, TRUE,
3822            US"perl"))
3823         {
3824         case 1: goto EXPAND_FAILED_CURLY;
3825         case 2:
3826         case 3: goto EXPAND_FAILED;
3827         }
3828
3829       /* If skipping, we don't actually do anything */
3830
3831       if (skipping) continue;
3832
3833       /* Start the interpreter if necessary */
3834
3835       if (!opt_perl_started)
3836         {
3837         uschar *initerror;
3838         if (opt_perl_startup == NULL)
3839           {
3840           expand_string_message = US"A setting of perl_startup is needed when "
3841             "using the Perl interpreter";
3842           goto EXPAND_FAILED;
3843           }
3844         DEBUG(D_any) debug_printf("Starting Perl interpreter\n");
3845         initerror = init_perl(opt_perl_startup);
3846         if (initerror != NULL)
3847           {
3848           expand_string_message =
3849             string_sprintf("error in perl_startup code: %s\n", initerror);
3850           goto EXPAND_FAILED;
3851           }
3852         opt_perl_started = TRUE;
3853         }
3854
3855       /* Call the function */
3856
3857       sub_arg[EXIM_PERL_MAX_ARGS + 1] = NULL;
3858       new_yield = call_perl_cat(yield, &size, &ptr, &expand_string_message,
3859         sub_arg[0], sub_arg + 1);
3860
3861       /* NULL yield indicates failure; if the message pointer has been set to
3862       NULL, the yield was undef, indicating a forced failure. Otherwise the
3863       message will indicate some kind of Perl error. */
3864
3865       if (new_yield == NULL)
3866         {
3867         if (expand_string_message == NULL)
3868           {
3869           expand_string_message =
3870             string_sprintf("Perl subroutine \"%s\" returned undef to force "
3871               "failure", sub_arg[0]);
3872           expand_string_forcedfail = TRUE;
3873           }
3874         goto EXPAND_FAILED;
3875         }
3876
3877       /* Yield succeeded. Ensure forcedfail is unset, just in case it got
3878       set during a callback from Perl. */
3879
3880       expand_string_forcedfail = FALSE;
3881       yield = new_yield;
3882       continue;
3883       }
3884     #endif /* EXIM_PERL */
3885
3886     /* Transform email address to "prvs" scheme to use
3887        as BATV-signed return path */
3888
3889     case EITEM_PRVS:
3890       {
3891       uschar *sub_arg[3];
3892       uschar *p,*domain;
3893
3894       switch(read_subs(sub_arg, 3, 2, &s, skipping, TRUE, US"prvs"))
3895         {
3896         case 1: goto EXPAND_FAILED_CURLY;
3897         case 2:
3898         case 3: goto EXPAND_FAILED;
3899         }
3900
3901       /* If skipping, we don't actually do anything */
3902       if (skipping) continue;
3903
3904       /* sub_arg[0] is the address */
3905       domain = Ustrrchr(sub_arg[0],'@');
3906       if ( (domain == NULL) || (domain == sub_arg[0]) || (Ustrlen(domain) == 1) )
3907         {
3908         expand_string_message = US"prvs first argument must be a qualified email address";
3909         goto EXPAND_FAILED;
3910         }
3911
3912       /* Calculate the hash. The second argument must be a single-digit
3913       key number, or unset. */
3914
3915       if (sub_arg[2] != NULL &&
3916           (!isdigit(sub_arg[2][0]) || sub_arg[2][1] != 0))
3917         {
3918         expand_string_message = US"prvs second argument must be a single digit";
3919         goto EXPAND_FAILED;
3920         }
3921
3922       p = prvs_hmac_sha1(sub_arg[0],sub_arg[1],sub_arg[2],prvs_daystamp(7));
3923       if (p == NULL)
3924         {
3925         expand_string_message = US"prvs hmac-sha1 conversion failed";
3926         goto EXPAND_FAILED;
3927         }
3928
3929       /* Now separate the domain from the local part */
3930       *domain++ = '\0';
3931
3932       yield = string_cat(yield,&size,&ptr,US"prvs=",5);
3933       string_cat(yield,&size,&ptr,(sub_arg[2] != NULL) ? sub_arg[2] : US"0", 1);
3934       string_cat(yield,&size,&ptr,prvs_daystamp(7),3);
3935       string_cat(yield,&size,&ptr,p,6);
3936       string_cat(yield,&size,&ptr,US"=",1);
3937       string_cat(yield,&size,&ptr,sub_arg[0],Ustrlen(sub_arg[0]));
3938       string_cat(yield,&size,&ptr,US"@",1);
3939       string_cat(yield,&size,&ptr,domain,Ustrlen(domain));
3940
3941       continue;
3942       }
3943
3944     /* Check a prvs-encoded address for validity */
3945
3946     case EITEM_PRVSCHECK:
3947       {
3948       uschar *sub_arg[3];
3949       int mysize = 0, myptr = 0;
3950       const pcre *re;
3951       uschar *p;
3952
3953       /* TF: Ugliness: We want to expand parameter 1 first, then set
3954          up expansion variables that are used in the expansion of
3955          parameter 2. So we clone the string for the first
3956          expansion, where we only expand parameter 1.
3957
3958          PH: Actually, that isn't necessary. The read_subs() function is
3959          designed to work this way for the ${if and ${lookup expansions. I've
3960          tidied the code.
3961       */
3962
3963       /* Reset expansion variables */
3964       prvscheck_result = NULL;
3965       prvscheck_address = NULL;
3966       prvscheck_keynum = NULL;
3967
3968       switch(read_subs(sub_arg, 1, 1, &s, skipping, FALSE, US"prvs"))
3969         {
3970         case 1: goto EXPAND_FAILED_CURLY;
3971         case 2:
3972         case 3: goto EXPAND_FAILED;
3973         }
3974
3975       re = regex_must_compile(US"^prvs\\=([0-9])([0-9]{3})([A-F0-9]{6})\\=(.+)\\@(.+)$",
3976                               TRUE,FALSE);
3977
3978       if (regex_match_and_setup(re,sub_arg[0],0,-1))
3979         {
3980         uschar *local_part = string_copyn(expand_nstring[4],expand_nlength[4]);
3981         uschar *key_num = string_copyn(expand_nstring[1],expand_nlength[1]);
3982         uschar *daystamp = string_copyn(expand_nstring[2],expand_nlength[2]);
3983         uschar *hash = string_copyn(expand_nstring[3],expand_nlength[3]);
3984         uschar *domain = string_copyn(expand_nstring[5],expand_nlength[5]);
3985
3986         DEBUG(D_expand) debug_printf("prvscheck localpart: %s\n", local_part);
3987         DEBUG(D_expand) debug_printf("prvscheck key number: %s\n", key_num);
3988         DEBUG(D_expand) debug_printf("prvscheck daystamp: %s\n", daystamp);
3989         DEBUG(D_expand) debug_printf("prvscheck hash: %s\n", hash);
3990         DEBUG(D_expand) debug_printf("prvscheck domain: %s\n", domain);
3991
3992         /* Set up expansion variables */
3993         prvscheck_address = string_cat(NULL, &mysize, &myptr, local_part, Ustrlen(local_part));
3994         string_cat(prvscheck_address,&mysize,&myptr,US"@",1);
3995         string_cat(prvscheck_address,&mysize,&myptr,domain,Ustrlen(domain));
3996         prvscheck_address[myptr] = '\0';
3997         prvscheck_keynum = string_copy(key_num);
3998
3999         /* Now expand the second argument */
4000         switch(read_subs(sub_arg, 1, 1, &s, skipping, FALSE, US"prvs"))
4001           {
4002           case 1: goto EXPAND_FAILED_CURLY;
4003           case 2:
4004           case 3: goto EXPAND_FAILED;
4005           }
4006
4007         /* Now we have the key and can check the address. */
4008
4009         p = prvs_hmac_sha1(prvscheck_address, sub_arg[0], prvscheck_keynum,
4010           daystamp);
4011
4012         if (p == NULL)
4013           {
4014           expand_string_message = US"hmac-sha1 conversion failed";
4015           goto EXPAND_FAILED;
4016           }
4017
4018         DEBUG(D_expand) debug_printf("prvscheck: received hash is %s\n", hash);
4019         DEBUG(D_expand) debug_printf("prvscheck:      own hash is %s\n", p);
4020
4021         if (Ustrcmp(p,hash) == 0)
4022           {
4023           /* Success, valid BATV address. Now check the expiry date. */
4024           uschar *now = prvs_daystamp(0);
4025           unsigned int inow = 0,iexpire = 1;
4026
4027           (void)sscanf(CS now,"%u",&inow);
4028           (void)sscanf(CS daystamp,"%u",&iexpire);
4029
4030           /* When "iexpire" is < 7, a "flip" has occured.
4031              Adjust "inow" accordingly. */
4032           if ( (iexpire < 7) && (inow >= 993) ) inow = 0;
4033
4034           if (iexpire >= inow)
4035             {
4036             prvscheck_result = US"1";
4037             DEBUG(D_expand) debug_printf("prvscheck: success, $pvrs_result set to 1\n");
4038             }
4039             else
4040             {
4041             prvscheck_result = NULL;
4042             DEBUG(D_expand) debug_printf("prvscheck: signature expired, $pvrs_result unset\n");
4043             }
4044           }
4045         else
4046           {
4047           prvscheck_result = NULL;
4048           DEBUG(D_expand) debug_printf("prvscheck: hash failure, $pvrs_result unset\n");
4049           }
4050
4051         /* Now expand the final argument. We leave this till now so that
4052         it can include $prvscheck_result. */
4053
4054         switch(read_subs(sub_arg, 1, 0, &s, skipping, TRUE, US"prvs"))
4055           {
4056           case 1: goto EXPAND_FAILED_CURLY;
4057           case 2:
4058           case 3: goto EXPAND_FAILED;
4059           }
4060
4061         if (sub_arg[0] == NULL || *sub_arg[0] == '\0')
4062           yield = string_cat(yield,&size,&ptr,prvscheck_address,Ustrlen(prvscheck_address));
4063         else
4064           yield = string_cat(yield,&size,&ptr,sub_arg[0],Ustrlen(sub_arg[0]));
4065
4066         /* Reset the "internal" variables afterwards, because they are in
4067         dynamic store that will be reclaimed if the expansion succeeded. */
4068
4069         prvscheck_address = NULL;
4070         prvscheck_keynum = NULL;
4071         }
4072       else
4073         {
4074         /* Does not look like a prvs encoded address, return the empty string.
4075            We need to make sure all subs are expanded first, so as to skip over
4076            the entire item. */
4077
4078         switch(read_subs(sub_arg, 2, 1, &s, skipping, TRUE, US"prvs"))
4079           {
4080           case 1: goto EXPAND_FAILED_CURLY;
4081           case 2:
4082           case 3: goto EXPAND_FAILED;
4083           }
4084         }
4085
4086       continue;
4087       }
4088
4089     /* Handle "readfile" to insert an entire file */
4090
4091     case EITEM_READFILE:
4092       {
4093       FILE *f;
4094       uschar *sub_arg[2];
4095
4096       if ((expand_forbid & RDO_READFILE) != 0)
4097         {
4098         expand_string_message = US"file insertions are not permitted";
4099         goto EXPAND_FAILED;
4100         }
4101
4102       switch(read_subs(sub_arg, 2, 1, &s, skipping, TRUE, US"readfile"))
4103         {
4104         case 1: goto EXPAND_FAILED_CURLY;
4105         case 2:
4106         case 3: goto EXPAND_FAILED;
4107         }
4108
4109       /* If skipping, we don't actually do anything */
4110
4111       if (skipping) continue;
4112
4113       /* Open the file and read it */
4114
4115       f = Ufopen(sub_arg[0], "rb");
4116       if (f == NULL)
4117         {
4118         expand_string_message = string_open_failed(errno, "%s", sub_arg[0]);
4119         goto EXPAND_FAILED;
4120         }
4121
4122       yield = cat_file(f, yield, &size, &ptr, sub_arg[1]);
4123       (void)fclose(f);
4124       continue;
4125       }
4126
4127     /* Handle "readsocket" to insert data from a Unix domain socket */
4128
4129     case EITEM_READSOCK:
4130       {
4131       int fd;
4132       int timeout = 5;
4133       int save_ptr = ptr;
4134       FILE *f;
4135       struct sockaddr_un sockun;         /* don't call this "sun" ! */
4136       uschar *arg;
4137       uschar *sub_arg[4];
4138
4139       if ((expand_forbid & RDO_READSOCK) != 0)
4140         {
4141         expand_string_message = US"socket insertions are not permitted";
4142         goto EXPAND_FAILED;
4143         }
4144
4145       /* Read up to 4 arguments, but don't do the end of item check afterwards,
4146       because there may be a string for expansion on failure. */
4147
4148       switch(read_subs(sub_arg, 4, 2, &s, skipping, FALSE, US"readsocket"))
4149         {
4150         case 1: goto EXPAND_FAILED_CURLY;
4151         case 2:                             /* Won't occur: no end check */
4152         case 3: goto EXPAND_FAILED;
4153         }
4154
4155       /* Sort out timeout, if given */
4156
4157       if (sub_arg[2] != NULL)
4158         {
4159         timeout = readconf_readtime(sub_arg[2], 0, FALSE);
4160         if (timeout < 0)
4161           {
4162           expand_string_message = string_sprintf("bad time value %s",
4163             sub_arg[2]);
4164           goto EXPAND_FAILED;
4165           }
4166         }
4167       else sub_arg[3] = NULL;                     /* No eol if no timeout */
4168
4169       /* If skipping, we don't actually do anything. Otherwise, arrange to
4170       connect to either an IP or a Unix socket. */
4171
4172       if (!skipping)
4173         {
4174         /* Handle an IP (internet) domain */
4175
4176         if (Ustrncmp(sub_arg[0], "inet:", 5) == 0)
4177           {
4178           BOOL connected = FALSE;
4179           int namelen, port;
4180           host_item shost;
4181           host_item *h;
4182           uschar *server_name = sub_arg[0] + 5;
4183           uschar *port_name = Ustrrchr(server_name, ':');
4184
4185           /* Sort out the port */
4186
4187           if (port_name == NULL)
4188             {
4189             expand_string_message =
4190               string_sprintf("missing port for readsocket %s", sub_arg[0]);
4191             goto EXPAND_FAILED;
4192             }
4193           *port_name++ = 0;           /* Terminate server name */
4194
4195           if (isdigit(*port_name))
4196             {
4197             uschar *end;
4198             port = Ustrtol(port_name, &end, 0);
4199             if (end != port_name + Ustrlen(port_name))
4200               {
4201               expand_string_message =
4202                 string_sprintf("invalid port number %s", port_name);
4203               goto EXPAND_FAILED;
4204               }
4205             }
4206           else
4207             {
4208             struct servent *service_info = getservbyname(CS port_name, "tcp");
4209             if (service_info == NULL)
4210               {
4211               expand_string_message = string_sprintf("unknown port \"%s\"",
4212                 port_name);
4213               goto EXPAND_FAILED;
4214               }
4215             port = ntohs(service_info->s_port);
4216             }
4217
4218           /* Sort out the server. */
4219
4220           shost.next = NULL;
4221           shost.address = NULL;
4222           shost.port = port;
4223           shost.mx = -1;
4224
4225           namelen = Ustrlen(server_name);
4226
4227           /* Anything enclosed in [] must be an IP address. */
4228
4229           if (server_name[0] == '[' &&
4230               server_name[namelen - 1] == ']')
4231             {
4232             server_name[namelen - 1] = 0;
4233             server_name++;
4234             if (string_is_ip_address(server_name, NULL) == 0)
4235               {
4236               expand_string_message =
4237                 string_sprintf("malformed IP address \"%s\"", server_name);
4238               goto EXPAND_FAILED;
4239               }
4240             shost.name = shost.address = server_name;
4241             }
4242
4243           /* Otherwise check for an unadorned IP address */
4244
4245           else if (string_is_ip_address(server_name, NULL) != 0)
4246             shost.name = shost.address = server_name;
4247
4248           /* Otherwise lookup IP address(es) from the name */
4249
4250           else
4251             {
4252             shost.name = server_name;
4253             if (host_find_byname(&shost, NULL, HOST_FIND_QUALIFY_SINGLE, NULL,
4254                 FALSE) != HOST_FOUND)
4255               {
4256               expand_string_message =
4257                 string_sprintf("no IP address found for host %s", shost.name);
4258               goto EXPAND_FAILED;
4259               }
4260             }
4261
4262           /* Try to connect to the server - test each IP till one works */
4263
4264           for (h = &shost; h != NULL; h = h->next)
4265             {
4266             int af = (Ustrchr(h->address, ':') != 0)? AF_INET6 : AF_INET;
4267             if ((fd = ip_socket(SOCK_STREAM, af)) == -1)
4268               {
4269               expand_string_message = string_sprintf("failed to create socket: "
4270                 "%s", strerror(errno));
4271               goto SOCK_FAIL;
4272               }
4273
4274             if (ip_connect(fd, af, h->address, port, timeout) == 0)
4275               {
4276               connected = TRUE;
4277               break;
4278               }
4279             }
4280
4281           if (!connected)
4282             {
4283             expand_string_message = string_sprintf("failed to connect to "
4284               "socket %s: couldn't connect to any host", sub_arg[0],
4285               strerror(errno));
4286             goto SOCK_FAIL;
4287             }
4288           }
4289
4290         /* Handle a Unix domain socket */
4291
4292         else
4293           {
4294           int rc;
4295           if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
4296             {
4297             expand_string_message = string_sprintf("failed to create socket: %s",
4298               strerror(errno));
4299             goto SOCK_FAIL;
4300             }
4301
4302           sockun.sun_family = AF_UNIX;
4303           sprintf(sockun.sun_path, "%.*s", (int)(sizeof(sockun.sun_path)-1),
4304             sub_arg[0]);
4305
4306           sigalrm_seen = FALSE;
4307           alarm(timeout);
4308           rc = connect(fd, (struct sockaddr *)(&sockun), sizeof(sockun));
4309           alarm(0);
4310           if (sigalrm_seen)
4311             {
4312             expand_string_message = US "socket connect timed out";
4313             goto SOCK_FAIL;
4314             }
4315           if (rc < 0)
4316             {
4317             expand_string_message = string_sprintf("failed to connect to socket "
4318               "%s: %s", sub_arg[0], strerror(errno));
4319             goto SOCK_FAIL;
4320             }
4321           }
4322
4323         DEBUG(D_expand) debug_printf("connected to socket %s\n", sub_arg[0]);
4324
4325         /* Write the request string, if not empty */
4326
4327         if (sub_arg[1][0] != 0)
4328           {
4329           int len = Ustrlen(sub_arg[1]);
4330           DEBUG(D_expand) debug_printf("writing \"%s\" to socket\n",
4331             sub_arg[1]);
4332           if (write(fd, sub_arg[1], len) != len)
4333             {
4334             expand_string_message = string_sprintf("request write to socket "
4335               "failed: %s", strerror(errno));
4336             goto SOCK_FAIL;
4337             }
4338           }
4339
4340         /* Shut down the sending side of the socket. This helps some servers to
4341         recognise that it is their turn to do some work. Just in case some
4342         system doesn't have this function, make it conditional. */
4343
4344         #ifdef SHUT_WR
4345         shutdown(fd, SHUT_WR);
4346         #endif
4347
4348         /* Now we need to read from the socket, under a timeout. The function
4349         that reads a file can be used. */
4350
4351         f = fdopen(fd, "rb");
4352         sigalrm_seen = FALSE;
4353         alarm(timeout);
4354         yield = cat_file(f, yield, &size, &ptr, sub_arg[3]);
4355         alarm(0);
4356         (void)fclose(f);
4357
4358         /* After a timeout, we restore the pointer in the result, that is,
4359         make sure we add nothing from the socket. */
4360
4361         if (sigalrm_seen)
4362           {
4363           ptr = save_ptr;
4364           expand_string_message = US "socket read timed out";
4365           goto SOCK_FAIL;
4366           }
4367         }
4368
4369       /* The whole thing has worked (or we were skipping). If there is a
4370       failure string following, we need to skip it. */
4371
4372       if (*s == '{')
4373         {
4374         if (expand_string_internal(s+1, TRUE, &s, TRUE, TRUE) == NULL)
4375           goto EXPAND_FAILED;
4376         if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4377         while (isspace(*s)) s++;
4378         }
4379       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4380       continue;
4381
4382       /* Come here on failure to create socket, connect socket, write to the
4383       socket, or timeout on reading. If another substring follows, expand and
4384       use it. Otherwise, those conditions give expand errors. */
4385
4386       SOCK_FAIL:
4387       if (*s != '{') goto EXPAND_FAILED;
4388       DEBUG(D_any) debug_printf("%s\n", expand_string_message);
4389       arg = expand_string_internal(s+1, TRUE, &s, FALSE, TRUE);
4390       if (arg == NULL) goto EXPAND_FAILED;
4391       yield = string_cat(yield, &size, &ptr, arg, Ustrlen(arg));
4392       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4393       while (isspace(*s)) s++;
4394       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4395       continue;
4396       }
4397
4398     /* Handle "run" to execute a program. */
4399
4400     case EITEM_RUN:
4401       {
4402       FILE *f;
4403       uschar *arg;
4404       uschar **argv;
4405       pid_t pid;
4406       int fd_in, fd_out;
4407       int lsize = 0;
4408       int lptr = 0;
4409
4410       if ((expand_forbid & RDO_RUN) != 0)
4411         {
4412         expand_string_message = US"running a command is not permitted";
4413         goto EXPAND_FAILED;
4414         }
4415
4416       while (isspace(*s)) s++;
4417       if (*s != '{') goto EXPAND_FAILED_CURLY;
4418       arg = expand_string_internal(s+1, TRUE, &s, skipping, TRUE);
4419       if (arg == NULL) goto EXPAND_FAILED;
4420       while (isspace(*s)) s++;
4421       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4422
4423       if (skipping)   /* Just pretend it worked when we're skipping */
4424         {
4425         runrc = 0;
4426         }
4427       else
4428         {
4429         if (!transport_set_up_command(&argv,    /* anchor for arg list */
4430             arg,                                /* raw command */
4431             FALSE,                              /* don't expand the arguments */
4432             0,                                  /* not relevant when... */
4433             NULL,                               /* no transporting address */
4434             US"${run} expansion",               /* for error messages */
4435             &expand_string_message))            /* where to put error message */
4436           {
4437           goto EXPAND_FAILED;
4438           }
4439
4440         /* Create the child process, making it a group leader. */
4441
4442         pid = child_open(argv, NULL, 0077, &fd_in, &fd_out, TRUE);
4443
4444         if (pid < 0)
4445           {
4446           expand_string_message =
4447             string_sprintf("couldn't create child process: %s", strerror(errno));
4448           goto EXPAND_FAILED;
4449           }
4450
4451         /* Nothing is written to the standard input. */
4452
4453         (void)close(fd_in);
4454
4455         /* Read the pipe to get the command's output into $value (which is kept
4456         in lookup_value). Read during execution, so that if the output exceeds
4457         the OS pipe buffer limit, we don't block forever. */
4458
4459         f = fdopen(fd_out, "rb");
4460         sigalrm_seen = FALSE;
4461         alarm(60);
4462         lookup_value = cat_file(f, lookup_value, &lsize, &lptr, NULL);
4463         alarm(0);
4464         (void)fclose(f);
4465
4466         /* Wait for the process to finish, applying the timeout, and inspect its
4467         return code for serious disasters. Simple non-zero returns are passed on.
4468         */
4469
4470         if (sigalrm_seen == TRUE || (runrc = child_close(pid, 30)) < 0)
4471           {
4472           if (sigalrm_seen == TRUE || runrc == -256)
4473             {
4474             expand_string_message = string_sprintf("command timed out");
4475             killpg(pid, SIGKILL);       /* Kill the whole process group */
4476             }
4477
4478           else if (runrc == -257)
4479             expand_string_message = string_sprintf("wait() failed: %s",
4480               strerror(errno));
4481
4482           else
4483             expand_string_message = string_sprintf("command killed by signal %d",
4484               -runrc);
4485
4486           goto EXPAND_FAILED;
4487           }
4488         }
4489
4490       /* Process the yes/no strings; $value may be useful in both cases */
4491
4492       switch(process_yesno(
4493                skipping,                     /* were previously skipping */
4494                runrc == 0,                   /* success/failure indicator */
4495                lookup_value,                 /* value to reset for string2 */
4496                &s,                           /* input pointer */
4497                &yield,                       /* output pointer */
4498                &size,                        /* output size */
4499                &ptr,                         /* output current point */
4500                US"run"))                     /* condition type */
4501         {
4502         case 1: goto EXPAND_FAILED;          /* when all is well, the */
4503         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
4504         }
4505
4506       continue;
4507       }
4508
4509     /* Handle character translation for "tr" */
4510
4511     case EITEM_TR:
4512       {
4513       int oldptr = ptr;
4514       int o2m;
4515       uschar *sub[3];
4516
4517       switch(read_subs(sub, 3, 3, &s, skipping, TRUE, US"tr"))
4518         {
4519         case 1: goto EXPAND_FAILED_CURLY;
4520         case 2:
4521         case 3: goto EXPAND_FAILED;
4522         }
4523
4524       yield = string_cat(yield, &size, &ptr, sub[0], Ustrlen(sub[0]));
4525       o2m = Ustrlen(sub[2]) - 1;
4526
4527       if (o2m >= 0) for (; oldptr < ptr; oldptr++)
4528         {
4529         uschar *m = Ustrrchr(sub[1], yield[oldptr]);
4530         if (m != NULL)
4531           {
4532           int o = m - sub[1];
4533           yield[oldptr] = sub[2][(o < o2m)? o : o2m];
4534           }
4535         }
4536
4537       continue;
4538       }
4539
4540     /* Handle "hash", "length", "nhash", and "substr" when they are given with
4541     expanded arguments. */
4542
4543     case EITEM_HASH:
4544     case EITEM_LENGTH:
4545     case EITEM_NHASH:
4546     case EITEM_SUBSTR:
4547       {
4548       int i;
4549       int len;
4550       uschar *ret;
4551       int val[2] = { 0, -1 };
4552       uschar *sub[3];
4553
4554       /* "length" takes only 2 arguments whereas the others take 2 or 3.
4555       Ensure that sub[2] is set in the ${length case. */
4556
4557       sub[2] = NULL;
4558       switch(read_subs(sub, (item_type == EITEM_LENGTH)? 2:3, 2, &s, skipping,
4559              TRUE, name))
4560         {
4561         case 1: goto EXPAND_FAILED_CURLY;
4562         case 2:
4563         case 3: goto EXPAND_FAILED;
4564         }
4565
4566       /* Juggle the arguments if there are only two of them: always move the
4567       string to the last position and make ${length{n}{str}} equivalent to
4568       ${substr{0}{n}{str}}. See the defaults for val[] above. */
4569
4570       if (sub[2] == NULL)
4571         {
4572         sub[2] = sub[1];
4573         sub[1] = NULL;
4574         if (item_type == EITEM_LENGTH)
4575           {
4576           sub[1] = sub[0];
4577           sub[0] = NULL;
4578           }
4579         }
4580
4581       for (i = 0; i < 2; i++)
4582         {
4583         if (sub[i] == NULL) continue;
4584         val[i] = (int)Ustrtol(sub[i], &ret, 10);
4585         if (*ret != 0 || (i != 0 && val[i] < 0))
4586           {
4587           expand_string_message = string_sprintf("\"%s\" is not a%s number "
4588             "(in \"%s\" expansion)", sub[i], (i != 0)? " positive" : "", name);
4589           goto EXPAND_FAILED;
4590           }
4591         }
4592
4593       ret =
4594         (item_type == EITEM_HASH)?
4595           compute_hash(sub[2], val[0], val[1], &len) :
4596         (item_type == EITEM_NHASH)?
4597           compute_nhash(sub[2], val[0], val[1], &len) :
4598           extract_substr(sub[2], val[0], val[1], &len);
4599
4600       if (ret == NULL) goto EXPAND_FAILED;
4601       yield = string_cat(yield, &size, &ptr, ret, len);
4602       continue;
4603       }
4604
4605     /* Handle HMAC computation: ${hmac{<algorithm>}{<secret>}{<text>}}
4606     This code originally contributed by Steve Haslam. It currently supports
4607     the use of MD5 and SHA-1 hashes.
4608
4609     We need some workspace that is large enough to handle all the supported
4610     hash types. Use macros to set the sizes rather than be too elaborate. */
4611
4612     #define MAX_HASHLEN      20
4613     #define MAX_HASHBLOCKLEN 64
4614
4615     case EITEM_HMAC:
4616       {
4617       uschar *sub[3];
4618       md5 md5_base;
4619       sha1 sha1_base;
4620       void *use_base;
4621       int type, i;
4622       int hashlen;      /* Number of octets for the hash algorithm's output */
4623       int hashblocklen; /* Number of octets the hash algorithm processes */
4624       uschar *keyptr, *p;
4625       unsigned int keylen;
4626
4627       uschar keyhash[MAX_HASHLEN];
4628       uschar innerhash[MAX_HASHLEN];
4629       uschar finalhash[MAX_HASHLEN];
4630       uschar finalhash_hex[2*MAX_HASHLEN];
4631       uschar innerkey[MAX_HASHBLOCKLEN];
4632       uschar outerkey[MAX_HASHBLOCKLEN];
4633
4634       switch (read_subs(sub, 3, 3, &s, skipping, TRUE, name))
4635         {
4636         case 1: goto EXPAND_FAILED_CURLY;
4637         case 2:
4638         case 3: goto EXPAND_FAILED;
4639         }
4640
4641       if (Ustrcmp(sub[0], "md5") == 0)
4642         {
4643         type = HMAC_MD5;
4644         use_base = &md5_base;
4645         hashlen = 16;
4646         hashblocklen = 64;
4647         }
4648       else if (Ustrcmp(sub[0], "sha1") == 0)
4649         {
4650         type = HMAC_SHA1;
4651         use_base = &sha1_base;
4652         hashlen = 20;
4653         hashblocklen = 64;
4654         }
4655       else
4656         {
4657         expand_string_message =
4658           string_sprintf("hmac algorithm \"%s\" is not recognised", sub[0]);
4659         goto EXPAND_FAILED;
4660         }
4661
4662       keyptr = sub[1];
4663       keylen = Ustrlen(keyptr);
4664
4665       /* If the key is longer than the hash block length, then hash the key
4666       first */
4667
4668       if (keylen > hashblocklen)
4669         {
4670         chash_start(type, use_base);
4671         chash_end(type, use_base, keyptr, keylen, keyhash);
4672         keyptr = keyhash;
4673         keylen = hashlen;
4674         }
4675
4676       /* Now make the inner and outer key values */
4677
4678       memset(innerkey, 0x36, hashblocklen);
4679       memset(outerkey, 0x5c, hashblocklen);
4680
4681       for (i = 0; i < keylen; i++)
4682         {
4683         innerkey[i] ^= keyptr[i];
4684         outerkey[i] ^= keyptr[i];
4685         }
4686
4687       /* Now do the hashes */
4688
4689       chash_start(type, use_base);
4690       chash_mid(type, use_base, innerkey);
4691       chash_end(type, use_base, sub[2], Ustrlen(sub[2]), innerhash);
4692
4693       chash_start(type, use_base);
4694       chash_mid(type, use_base, outerkey);
4695       chash_end(type, use_base, innerhash, hashlen, finalhash);
4696
4697       /* Encode the final hash as a hex string */
4698
4699       p = finalhash_hex;
4700       for (i = 0; i < hashlen; i++)
4701         {
4702         *p++ = hex_digits[(finalhash[i] & 0xf0) >> 4];
4703         *p++ = hex_digits[finalhash[i] & 0x0f];
4704         }
4705
4706       DEBUG(D_any) debug_printf("HMAC[%s](%.*s,%.*s)=%.*s\n", sub[0],
4707         (int)keylen, keyptr, Ustrlen(sub[2]), sub[2], hashlen*2, finalhash_hex);
4708
4709       yield = string_cat(yield, &size, &ptr, finalhash_hex, hashlen*2);
4710       }
4711
4712     continue;
4713
4714     /* Handle global substitution for "sg" - like Perl's s/xxx/yyy/g operator.
4715     We have to save the numerical variables and restore them afterwards. */
4716
4717     case EITEM_SG:
4718       {
4719       const pcre *re;
4720       int moffset, moffsetextra, slen;
4721       int roffset;
4722       int emptyopt;
4723       const uschar *rerror;
4724       uschar *subject;
4725       uschar *sub[3];
4726       int save_expand_nmax =
4727         save_expand_strings(save_expand_nstring, save_expand_nlength);
4728
4729       switch(read_subs(sub, 3, 3, &s, skipping, TRUE, US"sg"))
4730         {
4731         case 1: goto EXPAND_FAILED_CURLY;
4732         case 2:
4733         case 3: goto EXPAND_FAILED;
4734         }
4735
4736       /* Compile the regular expression */
4737
4738       re = pcre_compile(CS sub[1], PCRE_COPT, (const char **)&rerror, &roffset,
4739         NULL);
4740
4741       if (re == NULL)
4742         {
4743         expand_string_message = string_sprintf("regular expression error in "
4744           "\"%s\": %s at offset %d", sub[1], rerror, roffset);
4745         goto EXPAND_FAILED;
4746         }
4747
4748       /* Now run a loop to do the substitutions as often as necessary. It ends
4749       when there are no more matches. Take care over matches of the null string;
4750       do the same thing as Perl does. */
4751
4752       subject = sub[0];
4753       slen = Ustrlen(sub[0]);
4754       moffset = moffsetextra = 0;
4755       emptyopt = 0;
4756
4757       for (;;)
4758         {
4759         int ovector[3*(EXPAND_MAXN+1)];
4760         int n = pcre_exec(re, NULL, CS subject, slen, moffset + moffsetextra,
4761           PCRE_EOPT | emptyopt, ovector, sizeof(ovector)/sizeof(int));
4762         int nn;
4763         uschar *insert;
4764
4765         /* No match - if we previously set PCRE_NOTEMPTY after a null match, this
4766         is not necessarily the end. We want to repeat the match from one
4767         character further along, but leaving the basic offset the same (for
4768         copying below). We can't be at the end of the string - that was checked
4769         before setting PCRE_NOTEMPTY. If PCRE_NOTEMPTY is not set, we are
4770         finished; copy the remaining string and end the loop. */
4771
4772         if (n < 0)
4773           {
4774           if (emptyopt != 0)
4775             {
4776             moffsetextra = 1;
4777             emptyopt = 0;
4778             continue;
4779             }
4780           yield = string_cat(yield, &size, &ptr, subject+moffset, slen-moffset);
4781           break;
4782           }
4783
4784         /* Match - set up for expanding the replacement. */
4785
4786         if (n == 0) n = EXPAND_MAXN + 1;
4787         expand_nmax = 0;
4788         for (nn = 0; nn < n*2; nn += 2)
4789           {
4790           expand_nstring[expand_nmax] = subject + ovector[nn];
4791           expand_nlength[expand_nmax++] = ovector[nn+1] - ovector[nn];
4792           }
4793         expand_nmax--;
4794
4795         /* Copy the characters before the match, plus the expanded insertion. */
4796
4797         yield = string_cat(yield, &size, &ptr, subject + moffset,
4798           ovector[0] - moffset);
4799         insert = expand_string(sub[2]);
4800         if (insert == NULL) goto EXPAND_FAILED;
4801         yield = string_cat(yield, &size, &ptr, insert, Ustrlen(insert));
4802
4803         moffset = ovector[1];
4804         moffsetextra = 0;
4805         emptyopt = 0;
4806
4807         /* If we have matched an empty string, first check to see if we are at
4808         the end of the subject. If so, the loop is over. Otherwise, mimic
4809         what Perl's /g options does. This turns out to be rather cunning. First
4810         we set PCRE_NOTEMPTY and PCRE_ANCHORED and try the match a non-empty
4811         string at the same point. If this fails (picked up above) we advance to
4812         the next character. */
4813
4814         if (ovector[0] == ovector[1])
4815           {
4816           if (ovector[0] == slen) break;
4817           emptyopt = PCRE_NOTEMPTY | PCRE_ANCHORED;
4818           }
4819         }
4820
4821       /* All done - restore numerical variables. */
4822
4823       restore_expand_strings(save_expand_nmax, save_expand_nstring,
4824         save_expand_nlength);
4825       continue;
4826       }
4827
4828     /* Handle keyed and numbered substring extraction. If the first argument
4829     consists entirely of digits, then a numerical extraction is assumed. */
4830
4831     case EITEM_EXTRACT:
4832       {
4833       int i;
4834       int j = 2;
4835       int field_number = 1;
4836       BOOL field_number_set = FALSE;
4837       uschar *save_lookup_value = lookup_value;
4838       uschar *sub[3];
4839       int save_expand_nmax =
4840         save_expand_strings(save_expand_nstring, save_expand_nlength);
4841
4842       /* Read the arguments */
4843
4844       for (i = 0; i < j; i++)
4845         {
4846         while (isspace(*s)) s++;
4847         if (*s == '{')
4848           {
4849           sub[i] = expand_string_internal(s+1, TRUE, &s, skipping, TRUE);
4850           if (sub[i] == NULL) goto EXPAND_FAILED;
4851           if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4852
4853           /* After removal of leading and trailing white space, the first
4854           argument must not be empty; if it consists entirely of digits
4855           (optionally preceded by a minus sign), this is a numerical
4856           extraction, and we expect 3 arguments. */
4857
4858           if (i == 0)
4859             {
4860             int len;
4861             int x = 0;
4862             uschar *p = sub[0];
4863
4864             while (isspace(*p)) p++;
4865             sub[0] = p;
4866
4867             len = Ustrlen(p);
4868             while (len > 0 && isspace(p[len-1])) len--;
4869             p[len] = 0;
4870
4871             if (*p == 0 && !skipping)
4872               {
4873               expand_string_message = US"first argument of \"extract\" must "
4874                 "not be empty";
4875               goto EXPAND_FAILED;
4876               }
4877
4878             if (*p == '-')
4879               {
4880               field_number = -1;
4881               p++;
4882               }
4883             while (*p != 0 && isdigit(*p)) x = x * 10 + *p++ - '0';
4884             if (*p == 0)
4885               {
4886               field_number *= x;
4887               j = 3;               /* Need 3 args */
4888               field_number_set = TRUE;
4889               }
4890             }
4891           }
4892         else goto EXPAND_FAILED_CURLY;
4893         }
4894
4895       /* Extract either the numbered or the keyed substring into $value. If
4896       skipping, just pretend the extraction failed. */
4897
4898       lookup_value = skipping? NULL : field_number_set?
4899         expand_gettokened(field_number, sub[1], sub[2]) :
4900         expand_getkeyed(sub[0], sub[1]);
4901
4902       /* If no string follows, $value gets substituted; otherwise there can
4903       be yes/no strings, as for lookup or if. */
4904
4905       switch(process_yesno(
4906                skipping,                     /* were previously skipping */
4907                lookup_value != NULL,         /* success/failure indicator */
4908                save_lookup_value,            /* value to reset for string2 */
4909                &s,                           /* input pointer */
4910                &yield,                       /* output pointer */
4911                &size,                        /* output size */
4912                &ptr,                         /* output current point */
4913                US"extract"))                 /* condition type */
4914         {
4915         case 1: goto EXPAND_FAILED;          /* when all is well, the */
4916         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
4917         }
4918
4919       /* All done - restore numerical variables. */
4920
4921       restore_expand_strings(save_expand_nmax, save_expand_nstring,
4922         save_expand_nlength);
4923
4924       continue;
4925       }
4926
4927
4928     /* Handle list operations */
4929
4930     case EITEM_FILTER:
4931     case EITEM_MAP:
4932     case EITEM_REDUCE:
4933       {
4934       int sep = 0;
4935       int save_ptr = ptr;
4936       uschar outsep[2] = { '\0', '\0' };
4937       uschar *list, *expr, *temp;
4938       uschar *save_iterate_item = iterate_item;
4939       uschar *save_lookup_value = lookup_value;
4940
4941       while (isspace(*s)) s++;
4942       if (*s++ != '{') goto EXPAND_FAILED_CURLY;
4943
4944       list = expand_string_internal(s, TRUE, &s, skipping, TRUE);
4945       if (list == NULL) goto EXPAND_FAILED;
4946       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4947
4948       if (item_type == EITEM_REDUCE)
4949         {
4950         while (isspace(*s)) s++;
4951         if (*s++ != '{') goto EXPAND_FAILED_CURLY;
4952         temp = expand_string_internal(s, TRUE, &s, skipping, TRUE);
4953         if (temp == NULL) goto EXPAND_FAILED;
4954         lookup_value = temp;
4955         if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4956         }
4957
4958       while (isspace(*s)) s++;
4959       if (*s++ != '{') goto EXPAND_FAILED_CURLY;
4960
4961       expr = s;
4962
4963       /* For EITEM_FILTER, call eval_condition once, with result discarded (as
4964       if scanning a "false" part). This allows us to find the end of the
4965       condition, because if the list is empty, we won't actually evaluate the
4966       condition for real. For EITEM_MAP and EITEM_REDUCE, do the same, using
4967       the normal internal expansion function. */
4968
4969       if (item_type == EITEM_FILTER)
4970         {
4971         temp = eval_condition(expr, NULL);
4972         if (temp != NULL) s = temp;
4973         }
4974       else
4975         {
4976         temp = expand_string_internal(s, TRUE, &s, TRUE, TRUE);
4977         }
4978
4979       if (temp == NULL)
4980         {
4981         expand_string_message = string_sprintf("%s inside \"%s\" item",
4982           expand_string_message, name);
4983         goto EXPAND_FAILED;
4984         }
4985
4986       while (isspace(*s)) s++;
4987       if (*s++ != '}')
4988         {
4989         expand_string_message = string_sprintf("missing } at end of condition "
4990           "or expression inside \"%s\"", name);
4991         goto EXPAND_FAILED;
4992         }
4993
4994       while (isspace(*s)) s++;
4995       if (*s++ != '}')
4996         {
4997         expand_string_message = string_sprintf("missing } at end of \"%s\"",
4998           name);
4999         goto EXPAND_FAILED;
5000         }
5001
5002       /* If we are skipping, we can now just move on to the next item. When
5003       processing for real, we perform the iteration. */
5004
5005       if (skipping) continue;
5006       while ((iterate_item = string_nextinlist(&list, &sep, NULL, 0)) != NULL)
5007         {
5008         *outsep = (uschar)sep;      /* Separator as a string */
5009
5010         DEBUG(D_expand) debug_printf("%s: $item = \"%s\"\n", name, iterate_item);
5011
5012         if (item_type == EITEM_FILTER)
5013           {
5014           BOOL condresult;
5015           if (eval_condition(expr, &condresult) == NULL)
5016             {
5017             iterate_item = save_iterate_item;
5018             lookup_value = save_lookup_value;
5019             expand_string_message = string_sprintf("%s inside \"%s\" condition",
5020               expand_string_message, name);
5021             goto EXPAND_FAILED;
5022             }
5023           DEBUG(D_expand) debug_printf("%s: condition is %s\n", name,
5024             condresult? "true":"false");
5025           if (condresult)
5026             temp = iterate_item;    /* TRUE => include this item */
5027           else
5028             continue;               /* FALSE => skip this item */
5029           }
5030
5031         /* EITEM_MAP and EITEM_REDUCE */
5032
5033         else
5034           {
5035           temp = expand_string_internal(expr, TRUE, NULL, skipping, TRUE);
5036           if (temp == NULL)
5037             {
5038             iterate_item = save_iterate_item;
5039             expand_string_message = string_sprintf("%s inside \"%s\" item",
5040               expand_string_message, name);
5041             goto EXPAND_FAILED;
5042             }
5043           if (item_type == EITEM_REDUCE)
5044             {
5045             lookup_value = temp;      /* Update the value of $value */
5046             continue;                 /* and continue the iteration */
5047             }
5048           }
5049
5050         /* We reach here for FILTER if the condition is true, always for MAP,
5051         and never for REDUCE. The value in "temp" is to be added to the output
5052         list that is being created, ensuring that any occurrences of the
5053         separator character are doubled. Unless we are dealing with the first
5054         item of the output list, add in a space if the new item begins with the
5055         separator character, or is an empty string. */
5056
5057         if (ptr != save_ptr && (temp[0] == *outsep || temp[0] == 0))
5058           yield = string_cat(yield, &size, &ptr, US" ", 1);
5059
5060         /* Add the string in "temp" to the output list that we are building,
5061         This is done in chunks by searching for the separator character. */
5062
5063         for (;;)
5064           {
5065           size_t seglen = Ustrcspn(temp, outsep);
5066             yield = string_cat(yield, &size, &ptr, temp, seglen + 1);
5067
5068           /* If we got to the end of the string we output one character
5069           too many; backup and end the loop. Otherwise arrange to double the
5070           separator. */
5071
5072           if (temp[seglen] == '\0') { ptr--; break; }
5073           yield = string_cat(yield, &size, &ptr, outsep, 1);
5074           temp += seglen + 1;
5075           }
5076
5077         /* Output a separator after the string: we will remove the redundant
5078         final one at the end. */
5079
5080         yield = string_cat(yield, &size, &ptr, outsep, 1);
5081         }   /* End of iteration over the list loop */
5082
5083       /* REDUCE has generated no output above: output the final value of
5084       $value. */
5085
5086       if (item_type == EITEM_REDUCE)
5087         {
5088         yield = string_cat(yield, &size, &ptr, lookup_value,
5089           Ustrlen(lookup_value));
5090         lookup_value = save_lookup_value;  /* Restore $value */
5091         }
5092
5093       /* FILTER and MAP generate lists: if they have generated anything, remove
5094       the redundant final separator. Even though an empty item at the end of a
5095       list does not count, this is tidier. */
5096
5097       else if (ptr != save_ptr) ptr--;
5098
5099       /* Restore preserved $item */
5100
5101       iterate_item = save_iterate_item;
5102       continue;
5103       }
5104
5105
5106     /* If ${dlfunc support is configured, handle calling dynamically-loaded
5107     functions, unless locked out at this time. Syntax is ${dlfunc{file}{func}}
5108     or ${dlfunc{file}{func}{arg}} or ${dlfunc{file}{func}{arg1}{arg2}} or up to
5109     a maximum of EXPAND_DLFUNC_MAX_ARGS arguments (defined below). */
5110
5111     #define EXPAND_DLFUNC_MAX_ARGS 8
5112
5113     case EITEM_DLFUNC:
5114     #ifndef EXPAND_DLFUNC
5115     expand_string_message = US"\"${dlfunc\" encountered, but this facility "
5116       "is not included in this binary";
5117     goto EXPAND_FAILED;
5118
5119     #else   /* EXPAND_DLFUNC */
5120       {
5121       tree_node *t;
5122       exim_dlfunc_t *func;
5123       uschar *result;
5124       int status, argc;
5125       uschar *argv[EXPAND_DLFUNC_MAX_ARGS + 3];
5126
5127       if ((expand_forbid & RDO_DLFUNC) != 0)
5128         {
5129         expand_string_message =
5130           US"dynamically-loaded functions are not permitted";
5131         goto EXPAND_FAILED;
5132         }
5133
5134       switch(read_subs(argv, EXPAND_DLFUNC_MAX_ARGS + 2, 2, &s, skipping,
5135            TRUE, US"dlfunc"))
5136         {
5137         case 1: goto EXPAND_FAILED_CURLY;
5138         case 2:
5139         case 3: goto EXPAND_FAILED;
5140         }
5141
5142       /* If skipping, we don't actually do anything */
5143
5144       if (skipping) continue;
5145
5146       /* Look up the dynamically loaded object handle in the tree. If it isn't
5147       found, dlopen() the file and put the handle in the tree for next time. */
5148
5149       t = tree_search(dlobj_anchor, argv[0]);
5150       if (t == NULL)
5151         {
5152         void *handle = dlopen(CS argv[0], RTLD_LAZY);
5153         if (handle == NULL)
5154           {
5155           expand_string_message = string_sprintf("dlopen \"%s\" failed: %s",
5156             argv[0], dlerror());
5157           log_write(0, LOG_MAIN|LOG_PANIC, "%s", expand_string_message);
5158           goto EXPAND_FAILED;
5159           }
5160         t = store_get_perm(sizeof(tree_node) + Ustrlen(argv[0]));
5161         Ustrcpy(t->name, argv[0]);
5162         t->data.ptr = handle;
5163         (void)tree_insertnode(&dlobj_anchor, t);
5164         }
5165
5166       /* Having obtained the dynamically loaded object handle, look up the
5167       function pointer. */
5168
5169       func = (exim_dlfunc_t *)dlsym(t->data.ptr, CS argv[1]);
5170       if (func == NULL)
5171         {
5172         expand_string_message = string_sprintf("dlsym \"%s\" in \"%s\" failed: "
5173           "%s", argv[1], argv[0], dlerror());
5174         log_write(0, LOG_MAIN|LOG_PANIC, "%s", expand_string_message);
5175         goto EXPAND_FAILED;
5176         }
5177
5178       /* Call the function and work out what to do with the result. If it
5179       returns OK, we have a replacement string; if it returns DEFER then
5180       expansion has failed in a non-forced manner; if it returns FAIL then
5181       failure was forced; if it returns ERROR or any other value there's a
5182       problem, so panic slightly. In any case, assume that the function has
5183       side-effects on the store that must be preserved. */
5184
5185       resetok = FALSE;
5186       result = NULL;
5187       for (argc = 0; argv[argc] != NULL; argc++);
5188       status = func(&result, argc - 2, &argv[2]);
5189       if(status == OK)
5190         {
5191         if (result == NULL) result = US"";
5192         yield = string_cat(yield, &size, &ptr, result, Ustrlen(result));
5193         continue;
5194         }
5195       else
5196         {
5197         expand_string_message = result == NULL ? US"(no message)" : result;
5198         if(status == FAIL_FORCED) expand_string_forcedfail = TRUE;
5199           else if(status != FAIL)
5200             log_write(0, LOG_MAIN|LOG_PANIC, "dlfunc{%s}{%s} failed (%d): %s",
5201               argv[0], argv[1], status, expand_string_message);
5202         goto EXPAND_FAILED;
5203         }
5204       }
5205     #endif /* EXPAND_DLFUNC */
5206     }
5207
5208   /* Control reaches here if the name is not recognized as one of the more
5209   complicated expansion items. Check for the "operator" syntax (name terminated
5210   by a colon). Some of the operators have arguments, separated by _ from the
5211   name. */
5212
5213   if (*s == ':')
5214     {
5215     int c;
5216     uschar *arg = NULL;
5217     uschar *sub = expand_string_internal(s+1, TRUE, &s, skipping, TRUE);
5218     if (sub == NULL) goto EXPAND_FAILED;
5219     s++;
5220
5221     /* Owing to an historical mis-design, an underscore may be part of the
5222     operator name, or it may introduce arguments.  We therefore first scan the
5223     table of names that contain underscores. If there is no match, we cut off
5224     the arguments and then scan the main table. */
5225
5226     c = chop_match(name, op_table_underscore,
5227       sizeof(op_table_underscore)/sizeof(uschar *));
5228
5229     if (c < 0)
5230       {
5231       arg = Ustrchr(name, '_');
5232       if (arg != NULL) *arg = 0;
5233       c = chop_match(name, op_table_main,
5234         sizeof(op_table_main)/sizeof(uschar *));
5235       if (c >= 0) c += sizeof(op_table_underscore)/sizeof(uschar *);
5236       if (arg != NULL) *arg++ = '_';   /* Put back for error messages */
5237       }
5238
5239     /* If we are skipping, we don't need to perform the operation at all.
5240     This matters for operations like "mask", because the data may not be
5241     in the correct format when skipping. For example, the expression may test
5242     for the existence of $sender_host_address before trying to mask it. For
5243     other operations, doing them may not fail, but it is a waste of time. */
5244
5245     if (skipping && c >= 0) continue;
5246
5247     /* Otherwise, switch on the operator type */
5248
5249     switch(c)
5250       {
5251       case EOP_BASE62:
5252         {
5253         uschar *t;
5254         unsigned long int n = Ustrtoul(sub, &t, 10);
5255         if (*t != 0)
5256           {
5257           expand_string_message = string_sprintf("argument for base62 "
5258             "operator is \"%s\", which is not a decimal number", sub);
5259           goto EXPAND_FAILED;
5260           }
5261         t = string_base62(n);
5262         yield = string_cat(yield, &size, &ptr, t, Ustrlen(t));
5263         continue;
5264         }
5265
5266       /* Note that for Darwin and Cygwin, BASE_62 actually has the value 36 */
5267
5268       case EOP_BASE62D:
5269         {
5270         uschar buf[16];
5271         uschar *tt = sub;
5272         unsigned long int n = 0;
5273         while (*tt != 0)
5274           {
5275           uschar *t = Ustrchr(base62_chars, *tt++);
5276           if (t == NULL)
5277             {
5278             expand_string_message = string_sprintf("argument for base62d "
5279               "operator is \"%s\", which is not a base %d number", sub,
5280               BASE_62);
5281             goto EXPAND_FAILED;
5282             }
5283           n = n * BASE_62 + (t - base62_chars);
5284           }
5285         (void)sprintf(CS buf, "%ld", n);
5286         yield = string_cat(yield, &size, &ptr, buf, Ustrlen(buf));
5287         continue;
5288         }
5289
5290       case EOP_EXPAND:
5291         {
5292         uschar *expanded = expand_string_internal(sub, FALSE, NULL, skipping, TRUE);
5293         if (expanded == NULL)
5294           {
5295           expand_string_message =
5296             string_sprintf("internal expansion of \"%s\" failed: %s", sub,
5297               expand_string_message);
5298           goto EXPAND_FAILED;
5299           }
5300         yield = string_cat(yield, &size, &ptr, expanded, Ustrlen(expanded));
5301         continue;
5302         }
5303
5304       case EOP_LC:
5305         {
5306         int count = 0;
5307         uschar *t = sub - 1;
5308         while (*(++t) != 0) { *t = tolower(*t); count++; }
5309         yield = string_cat(yield, &size, &ptr, sub, count);
5310         continue;
5311         }
5312
5313       case EOP_UC:
5314         {
5315         int count = 0;
5316         uschar *t = sub - 1;
5317         while (*(++t) != 0) { *t = toupper(*t); count++; }
5318         yield = string_cat(yield, &size, &ptr, sub, count);
5319         continue;
5320         }
5321
5322       case EOP_MD5:
5323         {
5324         md5 base;
5325         uschar digest[16];
5326         int j;
5327         char st[33];
5328         md5_start(&base);
5329         md5_end(&base, sub, Ustrlen(sub), digest);
5330         for(j = 0; j < 16; j++) sprintf(st+2*j, "%02x", digest[j]);
5331         yield = string_cat(yield, &size, &ptr, US st, (int)strlen(st));
5332         continue;
5333         }
5334
5335       case EOP_SHA1:
5336         {
5337         sha1 base;
5338         uschar digest[20];
5339         int j;
5340         char st[41];
5341         sha1_start(&base);
5342         sha1_end(&base, sub, Ustrlen(sub), digest);
5343         for(j = 0; j < 20; j++) sprintf(st+2*j, "%02X", digest[j]);
5344         yield = string_cat(yield, &size, &ptr, US st, (int)strlen(st));
5345         continue;
5346         }
5347
5348       /* Convert hex encoding to base64 encoding */
5349
5350       case EOP_HEX2B64:
5351         {
5352         int c = 0;
5353         int b = -1;
5354         uschar *in = sub;
5355         uschar *out = sub;
5356         uschar *enc;
5357
5358         for (enc = sub; *enc != 0; enc++)
5359           {
5360           if (!isxdigit(*enc))
5361             {
5362             expand_string_message = string_sprintf("\"%s\" is not a hex "
5363               "string", sub);
5364             goto EXPAND_FAILED;
5365             }
5366           c++;
5367           }
5368
5369         if ((c & 1) != 0)
5370           {
5371           expand_string_message = string_sprintf("\"%s\" contains an odd "
5372             "number of characters", sub);
5373           goto EXPAND_FAILED;
5374           }
5375
5376         while ((c = *in++) != 0)
5377           {
5378           if (isdigit(c)) c -= '0';
5379           else c = toupper(c) - 'A' + 10;
5380           if (b == -1)
5381             {
5382             b = c << 4;
5383             }
5384           else
5385             {
5386             *out++ = b | c;
5387             b = -1;
5388             }
5389           }
5390
5391         enc = auth_b64encode(sub, out - sub);
5392         yield = string_cat(yield, &size, &ptr, enc, Ustrlen(enc));
5393         continue;
5394         }
5395
5396       /* mask applies a mask to an IP address; for example the result of
5397       ${mask:131.111.10.206/28} is 131.111.10.192/28. */
5398
5399       case EOP_MASK:
5400         {
5401         int count;
5402         uschar *endptr;
5403         int binary[4];
5404         int mask, maskoffset;
5405         int type = string_is_ip_address(sub, &maskoffset);
5406         uschar buffer[64];
5407
5408         if (type == 0)
5409           {
5410           expand_string_message = string_sprintf("\"%s\" is not an IP address",
5411            sub);
5412           goto EXPAND_FAILED;
5413           }
5414
5415         if (maskoffset == 0)
5416           {
5417           expand_string_message = string_sprintf("missing mask value in \"%s\"",
5418             sub);
5419           goto EXPAND_FAILED;
5420           }
5421
5422         mask = Ustrtol(sub + maskoffset + 1, &endptr, 10);
5423
5424         if (*endptr != 0 || mask < 0 || mask > ((type == 4)? 32 : 128))
5425           {
5426           expand_string_message = string_sprintf("mask value too big in \"%s\"",
5427             sub);
5428           goto EXPAND_FAILED;
5429           }
5430
5431         /* Convert the address to binary integer(s) and apply the mask */
5432
5433         sub[maskoffset] = 0;
5434         count = host_aton(sub, binary);
5435         host_mask(count, binary, mask);
5436
5437         /* Convert to masked textual format and add to output. */
5438
5439         yield = string_cat(yield, &size, &ptr, buffer,
5440           host_nmtoa(count, binary, mask, buffer, '.'));
5441         continue;
5442         }
5443
5444       case EOP_ADDRESS:
5445       case EOP_LOCAL_PART:
5446       case EOP_DOMAIN:
5447         {
5448         uschar *error;
5449         int start, end, domain;
5450         uschar *t = parse_extract_address(sub, &error, &start, &end, &domain,
5451           FALSE);
5452         if (t != NULL)
5453           {
5454           if (c != EOP_DOMAIN)
5455             {
5456             if (c == EOP_LOCAL_PART && domain != 0) end = start + domain - 1;
5457             yield = string_cat(yield, &size, &ptr, sub+start, end-start);
5458             }
5459           else if (domain != 0)
5460             {
5461             domain += start;
5462             yield = string_cat(yield, &size, &ptr, sub+domain, end-domain);
5463             }
5464           }
5465         continue;
5466         }
5467
5468       case EOP_ADDRESSES:
5469         {
5470         uschar outsep[2] = { ':', '\0' };
5471         uschar *address, *error;
5472         int save_ptr = ptr;
5473         int start, end, domain;  /* Not really used */
5474
5475         while (isspace(*sub)) sub++;
5476         if (*sub == '>') { *outsep = *++sub; ++sub; }
5477         parse_allow_group = TRUE;
5478
5479         for (;;)
5480           {
5481           uschar *p = parse_find_address_end(sub, FALSE);
5482           uschar saveend = *p;
5483           *p = '\0';
5484           address = parse_extract_address(sub, &error, &start, &end, &domain,
5485             FALSE);
5486           *p = saveend;
5487
5488           /* Add the address to the output list that we are building. This is
5489           done in chunks by searching for the separator character. At the
5490           start, unless we are dealing with the first address of the output
5491           list, add in a space if the new address begins with the separator
5492           character, or is an empty string. */
5493
5494           if (address != NULL)
5495             {
5496             if (ptr != save_ptr && address[0] == *outsep)
5497               yield = string_cat(yield, &size, &ptr, US" ", 1);
5498
5499             for (;;)
5500               {
5501               size_t seglen = Ustrcspn(address, outsep);
5502               yield = string_cat(yield, &size, &ptr, address, seglen + 1);
5503
5504               /* If we got to the end of the string we output one character
5505               too many. */
5506
5507               if (address[seglen] == '\0') { ptr--; break; }
5508               yield = string_cat(yield, &size, &ptr, outsep, 1);
5509               address += seglen + 1;
5510               }
5511
5512             /* Output a separator after the string: we will remove the
5513             redundant final one at the end. */
5514
5515             yield = string_cat(yield, &size, &ptr, outsep, 1);
5516             }
5517
5518           if (saveend == '\0') break;
5519           sub = p + 1;
5520           }
5521
5522         /* If we have generated anything, remove the redundant final
5523         separator. */
5524
5525         if (ptr != save_ptr) ptr--;
5526         parse_allow_group = FALSE;
5527         continue;
5528         }
5529
5530
5531       /* quote puts a string in quotes if it is empty or contains anything
5532       other than alphamerics, underscore, dot, or hyphen.
5533
5534       quote_local_part puts a string in quotes if RFC 2821/2822 requires it to
5535       be quoted in order to be a valid local part.
5536
5537       In both cases, newlines and carriage returns are converted into \n and \r
5538       respectively */
5539
5540       case EOP_QUOTE:
5541       case EOP_QUOTE_LOCAL_PART:
5542       if (arg == NULL)
5543         {
5544         BOOL needs_quote = (*sub == 0);      /* TRUE for empty string */
5545         uschar *t = sub - 1;
5546
5547         if (c == EOP_QUOTE)
5548           {
5549           while (!needs_quote && *(++t) != 0)
5550             needs_quote = !isalnum(*t) && !strchr("_-.", *t);
5551           }
5552         else  /* EOP_QUOTE_LOCAL_PART */
5553           {
5554           while (!needs_quote && *(++t) != 0)
5555             needs_quote = !isalnum(*t) &&
5556               strchr("!#$%&'*+-/=?^_`{|}~", *t) == NULL &&
5557               (*t != '.' || t == sub || t[1] == 0);
5558           }
5559
5560         if (needs_quote)
5561           {
5562           yield = string_cat(yield, &size, &ptr, US"\"", 1);
5563           t = sub - 1;
5564           while (*(++t) != 0)
5565             {
5566             if (*t == '\n')
5567               yield = string_cat(yield, &size, &ptr, US"\\n", 2);
5568             else if (*t == '\r')
5569               yield = string_cat(yield, &size, &ptr, US"\\r", 2);
5570             else
5571               {
5572               if (*t == '\\' || *t == '"')
5573                 yield = string_cat(yield, &size, &ptr, US"\\", 1);
5574               yield = string_cat(yield, &size, &ptr, t, 1);
5575               }
5576             }
5577           yield = string_cat(yield, &size, &ptr, US"\"", 1);
5578           }
5579         else yield = string_cat(yield, &size, &ptr, sub, Ustrlen(sub));
5580         continue;
5581         }
5582
5583       /* quote_lookuptype does lookup-specific quoting */
5584
5585       else
5586         {
5587         int n;
5588         uschar *opt = Ustrchr(arg, '_');
5589
5590         if (opt != NULL) *opt++ = 0;
5591
5592         n = search_findtype(arg, Ustrlen(arg));
5593         if (n < 0)
5594           {
5595           expand_string_message = search_error_message;
5596           goto EXPAND_FAILED;
5597           }
5598
5599         if (lookup_list[n]->quote != NULL)
5600           sub = (lookup_list[n]->quote)(sub, opt);
5601         else if (opt != NULL) sub = NULL;
5602
5603         if (sub == NULL)
5604           {
5605           expand_string_message = string_sprintf(
5606             "\"%s\" unrecognized after \"${quote_%s\"",
5607             opt, arg);
5608           goto EXPAND_FAILED;
5609           }
5610
5611         yield = string_cat(yield, &size, &ptr, sub, Ustrlen(sub));
5612         continue;
5613         }
5614
5615       /* rx quote sticks in \ before any non-alphameric character so that
5616       the insertion works in a regular expression. */
5617
5618       case EOP_RXQUOTE:
5619         {
5620         uschar *t = sub - 1;
5621         while (*(++t) != 0)
5622           {
5623           if (!isalnum(*t))
5624             yield = string_cat(yield, &size, &ptr, US"\\", 1);
5625           yield = string_cat(yield, &size, &ptr, t, 1);
5626           }
5627         continue;
5628         }
5629
5630       /* RFC 2047 encodes, assuming headers_charset (default ISO 8859-1) as
5631       prescribed by the RFC, if there are characters that need to be encoded */
5632
5633       case EOP_RFC2047:
5634         {
5635         uschar buffer[2048];
5636         uschar *string = parse_quote_2047(sub, Ustrlen(sub), headers_charset,
5637           buffer, sizeof(buffer), FALSE);
5638         yield = string_cat(yield, &size, &ptr, string, Ustrlen(string));
5639         continue;
5640         }
5641
5642       /* RFC 2047 decode */
5643
5644       case EOP_RFC2047D:
5645         {
5646         int len;
5647         uschar *error;
5648         uschar *decoded = rfc2047_decode(sub, check_rfc2047_length,
5649           headers_charset, '?', &len, &error);
5650         if (error != NULL)
5651           {
5652           expand_string_message = error;
5653           goto EXPAND_FAILED;
5654           }
5655         yield = string_cat(yield, &size, &ptr, decoded, len);
5656         continue;
5657         }
5658
5659       /* from_utf8 converts UTF-8 to 8859-1, turning non-existent chars into
5660       underscores */
5661
5662       case EOP_FROM_UTF8:
5663         {
5664         while (*sub != 0)
5665           {
5666           int c;
5667           uschar buff[4];
5668           GETUTF8INC(c, sub);
5669           if (c > 255) c = '_';
5670           buff[0] = c;
5671           yield = string_cat(yield, &size, &ptr, buff, 1);
5672           }
5673         continue;
5674         }
5675
5676       /* escape turns all non-printing characters into escape sequences. */
5677
5678       case EOP_ESCAPE:
5679         {
5680         uschar *t = string_printing(sub);
5681         yield = string_cat(yield, &size, &ptr, t, Ustrlen(t));
5682         continue;
5683         }
5684
5685       /* Handle numeric expression evaluation */
5686
5687       case EOP_EVAL:
5688       case EOP_EVAL10:
5689         {
5690         uschar *save_sub = sub;
5691         uschar *error = NULL;
5692         int n = eval_expr(&sub, (c == EOP_EVAL10), &error, FALSE);
5693         if (error != NULL)
5694           {
5695           expand_string_message = string_sprintf("error in expression "
5696             "evaluation: %s (after processing \"%.*s\")", error, sub-save_sub,
5697               save_sub);
5698           goto EXPAND_FAILED;
5699           }
5700         sprintf(CS var_buffer, "%d", n);
5701         yield = string_cat(yield, &size, &ptr, var_buffer, Ustrlen(var_buffer));
5702         continue;
5703         }
5704
5705       /* Handle time period formating */
5706
5707       case EOP_TIME_EVAL:
5708         {
5709         int n = readconf_readtime(sub, 0, FALSE);
5710         if (n < 0)
5711           {
5712           expand_string_message = string_sprintf("string \"%s\" is not an "
5713             "Exim time interval in \"%s\" operator", sub, name);
5714           goto EXPAND_FAILED;
5715           }
5716         sprintf(CS var_buffer, "%d", n);
5717         yield = string_cat(yield, &size, &ptr, var_buffer, Ustrlen(var_buffer));
5718         continue;
5719         }
5720
5721       case EOP_TIME_INTERVAL:
5722         {
5723         int n;
5724         uschar *t = read_number(&n, sub);
5725         if (*t != 0) /* Not A Number*/
5726           {
5727           expand_string_message = string_sprintf("string \"%s\" is not a "
5728             "positive number in \"%s\" operator", sub, name);
5729           goto EXPAND_FAILED;
5730           }
5731         t = readconf_printtime(n);
5732         yield = string_cat(yield, &size, &ptr, t, Ustrlen(t));
5733         continue;
5734         }
5735
5736       /* Convert string to base64 encoding */
5737
5738       case EOP_STR2B64:
5739         {
5740         uschar *encstr = auth_b64encode(sub, Ustrlen(sub));
5741         yield = string_cat(yield, &size, &ptr, encstr, Ustrlen(encstr));
5742         continue;
5743         }
5744
5745       /* strlen returns the length of the string */
5746
5747       case EOP_STRLEN:
5748         {
5749         uschar buff[24];
5750         (void)sprintf(CS buff, "%d", Ustrlen(sub));
5751         yield = string_cat(yield, &size, &ptr, buff, Ustrlen(buff));
5752         continue;
5753         }
5754
5755       /* length_n or l_n takes just the first n characters or the whole string,
5756       whichever is the shorter;
5757
5758       substr_m_n, and s_m_n take n characters from offset m; negative m take
5759       from the end; l_n is synonymous with s_0_n. If n is omitted in substr it
5760       takes the rest, either to the right or to the left.
5761
5762       hash_n or h_n makes a hash of length n from the string, yielding n
5763       characters from the set a-z; hash_n_m makes a hash of length n, but
5764       uses m characters from the set a-zA-Z0-9.
5765
5766       nhash_n returns a single number between 0 and n-1 (in text form), while
5767       nhash_n_m returns a div/mod hash as two numbers "a/b". The first lies
5768       between 0 and n-1 and the second between 0 and m-1. */
5769
5770       case EOP_LENGTH:
5771       case EOP_L:
5772       case EOP_SUBSTR:
5773       case EOP_S:
5774       case EOP_HASH:
5775       case EOP_H:
5776       case EOP_NHASH:
5777       case EOP_NH:
5778         {
5779         int sign = 1;
5780         int value1 = 0;
5781         int value2 = -1;
5782         int *pn;
5783         int len;
5784         uschar *ret;
5785
5786         if (arg == NULL)
5787           {
5788           expand_string_message = string_sprintf("missing values after %s",
5789             name);
5790           goto EXPAND_FAILED;
5791           }
5792
5793         /* "length" has only one argument, effectively being synonymous with
5794         substr_0_n. */
5795
5796         if (c == EOP_LENGTH || c == EOP_L)
5797           {
5798           pn = &value2;
5799           value2 = 0;
5800           }
5801
5802         /* The others have one or two arguments; for "substr" the first may be
5803         negative. The second being negative means "not supplied". */
5804
5805         else
5806           {
5807           pn = &value1;
5808           if (name[0] == 's' && *arg == '-') { sign = -1; arg++; }
5809           }
5810
5811         /* Read up to two numbers, separated by underscores */
5812
5813         ret = arg;
5814         while (*arg != 0)
5815           {
5816           if (arg != ret && *arg == '_' && pn == &value1)
5817             {
5818             pn = &value2;
5819             value2 = 0;
5820             if (arg[1] != 0) arg++;
5821             }
5822           else if (!isdigit(*arg))
5823             {
5824             expand_string_message =
5825               string_sprintf("non-digit after underscore in \"%s\"", name);
5826             goto EXPAND_FAILED;
5827             }
5828           else *pn = (*pn)*10 + *arg++ - '0';
5829           }
5830         value1 *= sign;
5831
5832         /* Perform the required operation */
5833
5834         ret =
5835           (c == EOP_HASH || c == EOP_H)?
5836              compute_hash(sub, value1, value2, &len) :
5837           (c == EOP_NHASH || c == EOP_NH)?
5838              compute_nhash(sub, value1, value2, &len) :
5839              extract_substr(sub, value1, value2, &len);
5840
5841         if (ret == NULL) goto EXPAND_FAILED;
5842         yield = string_cat(yield, &size, &ptr, ret, len);
5843         continue;
5844         }
5845
5846       /* Stat a path */
5847
5848       case EOP_STAT:
5849         {
5850         uschar *s;
5851         uschar smode[12];
5852         uschar **modetable[3];
5853         int i;
5854         mode_t mode;
5855         struct stat st;
5856
5857         if ((expand_forbid & RDO_EXISTS) != 0)
5858           {
5859           expand_string_message = US"Use of the stat() expansion is not permitted";
5860           goto EXPAND_FAILED;
5861           }
5862
5863         if (stat(CS sub, &st) < 0)
5864           {
5865           expand_string_message = string_sprintf("stat(%s) failed: %s",
5866             sub, strerror(errno));
5867           goto EXPAND_FAILED;
5868           }
5869         mode = st.st_mode;
5870         switch (mode & S_IFMT)
5871           {
5872           case S_IFIFO: smode[0] = 'p'; break;
5873           case S_IFCHR: smode[0] = 'c'; break;
5874           case S_IFDIR: smode[0] = 'd'; break;
5875           case S_IFBLK: smode[0] = 'b'; break;
5876           case S_IFREG: smode[0] = '-'; break;
5877           default: smode[0] = '?'; break;
5878           }
5879
5880         modetable[0] = ((mode & 01000) == 0)? mtable_normal : mtable_sticky;
5881         modetable[1] = ((mode & 02000) == 0)? mtable_normal : mtable_setid;
5882         modetable[2] = ((mode & 04000) == 0)? mtable_normal : mtable_setid;
5883
5884         for (i = 0; i < 3; i++)
5885           {
5886           memcpy(CS(smode + 7 - i*3), CS(modetable[i][mode & 7]), 3);
5887           mode >>= 3;
5888           }
5889
5890         smode[10] = 0;
5891         s = string_sprintf("mode=%04lo smode=%s inode=%ld device=%ld links=%ld "
5892           "uid=%ld gid=%ld size=" OFF_T_FMT " atime=%ld mtime=%ld ctime=%ld",
5893           (long)(st.st_mode & 077777), smode, (long)st.st_ino,
5894           (long)st.st_dev, (long)st.st_nlink, (long)st.st_uid,
5895           (long)st.st_gid, st.st_size, (long)st.st_atime,
5896           (long)st.st_mtime, (long)st.st_ctime);
5897         yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
5898         continue;
5899         }
5900
5901       /* pseudo-random number less than N */
5902
5903       case EOP_RANDINT:
5904         {
5905         int max;
5906         uschar *s;
5907
5908         max = expand_string_integer(sub, TRUE);
5909         if (expand_string_message != NULL)
5910           goto EXPAND_FAILED;
5911         s = string_sprintf("%d", pseudo_random_number(max));
5912         yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
5913         continue;
5914         }
5915
5916       /* Reverse IP, including IPv6 to dotted-nibble */
5917
5918       case EOP_REVERSE_IP:
5919         {
5920         int family, maskptr;
5921         uschar reversed[128];
5922
5923         family = string_is_ip_address(sub, &maskptr);
5924         if (family == 0)
5925           {
5926           expand_string_message = string_sprintf(
5927               "reverse_ip() not given an IP address [%s]", sub);
5928           goto EXPAND_FAILED;
5929           }
5930         invert_address(reversed, sub);
5931         yield = string_cat(yield, &size, &ptr, reversed, Ustrlen(reversed));
5932         continue;
5933         }
5934
5935       /* Unknown operator */
5936
5937       default:
5938       expand_string_message =
5939         string_sprintf("unknown expansion operator \"%s\"", name);
5940       goto EXPAND_FAILED;
5941       }
5942     }
5943
5944   /* Handle a plain name. If this is the first thing in the expansion, release
5945   the pre-allocated buffer. If the result data is known to be in a new buffer,
5946   newsize will be set to the size of that buffer, and we can just point at that
5947   store instead of copying. Many expansion strings contain just one reference,
5948   so this is a useful optimization, especially for humungous headers
5949   ($message_headers). */
5950
5951   if (*s++ == '}')
5952     {
5953     int len;
5954     int newsize = 0;
5955     if (ptr == 0)
5956       {
5957       if (resetok) store_reset(yield);
5958       yield = NULL;
5959       size = 0;
5960       }
5961     value = find_variable(name, FALSE, skipping, &newsize);
5962     if (value == NULL)
5963       {
5964       expand_string_message =
5965         string_sprintf("unknown variable in \"${%s}\"", name);
5966       check_variable_error_message(name);
5967       goto EXPAND_FAILED;
5968       }
5969     len = Ustrlen(value);
5970     if (yield == NULL && newsize != 0)
5971       {
5972       yield = value;
5973       size = newsize;
5974       ptr = len;
5975       }
5976     else yield = string_cat(yield, &size, &ptr, value, len);
5977     continue;
5978     }
5979
5980   /* Else there's something wrong */
5981
5982   expand_string_message =
5983     string_sprintf("\"${%s\" is not a known operator (or a } is missing "
5984     "in a variable reference)", name);
5985   goto EXPAND_FAILED;
5986   }
5987
5988 /* If we hit the end of the string when ket_ends is set, there is a missing
5989 terminating brace. */
5990
5991 if (ket_ends && *s == 0)
5992   {
5993   expand_string_message = malformed_header?
5994     US"missing } at end of string - could be header name not terminated by colon"
5995     :
5996     US"missing } at end of string";
5997   goto EXPAND_FAILED;
5998   }
5999
6000 /* Expansion succeeded; yield may still be NULL here if nothing was actually
6001 added to the string. If so, set up an empty string. Add a terminating zero. If
6002 left != NULL, return a pointer to the terminator. */
6003
6004 if (yield == NULL) yield = store_get(1);
6005 yield[ptr] = 0;
6006 if (left != NULL) *left = s;
6007
6008 /* Any stacking store that was used above the final string is no longer needed.
6009 In many cases the final string will be the first one that was got and so there
6010 will be optimal store usage. */
6011
6012 if (resetok) store_reset(yield + ptr + 1);
6013 DEBUG(D_expand)
6014   {
6015   debug_printf("expanding: %.*s\n   result: %s\n", (int)(s - string), string,
6016     yield);
6017   if (skipping) debug_printf("skipping: result is not used\n");
6018   }
6019 return yield;
6020
6021 /* This is the failure exit: easiest to program with a goto. We still need
6022 to update the pointer to the terminator, for cases of nested calls with "fail".
6023 */
6024
6025 EXPAND_FAILED_CURLY:
6026 expand_string_message = malformed_header?
6027   US"missing or misplaced { or } - could be header name not terminated by colon"
6028   :
6029   US"missing or misplaced { or }";
6030
6031 /* At one point, Exim reset the store to yield (if yield was not NULL), but
6032 that is a bad idea, because expand_string_message is in dynamic store. */
6033
6034 EXPAND_FAILED:
6035 if (left != NULL) *left = s;
6036 DEBUG(D_expand)
6037   {
6038   debug_printf("failed to expand: %s\n", string);
6039   debug_printf("   error message: %s\n", expand_string_message);
6040   if (expand_string_forcedfail) debug_printf("failure was forced\n");
6041   }
6042 return NULL;
6043 }
6044
6045
6046 /* This is the external function call. Do a quick check for any expansion
6047 metacharacters, and if there are none, just return the input string.
6048
6049 Argument: the string to be expanded
6050 Returns:  the expanded string, or NULL if expansion failed; if failure was
6051           due to a lookup deferring, search_find_defer will be TRUE
6052 */
6053
6054 uschar *
6055 expand_string(uschar *string)
6056 {
6057 search_find_defer = FALSE;
6058 malformed_header = FALSE;
6059 return (Ustrpbrk(string, "$\\") == NULL)? string :
6060   expand_string_internal(string, FALSE, NULL, FALSE, TRUE);
6061 }
6062
6063
6064
6065 /*************************************************
6066 *              Expand and copy                   *
6067 *************************************************/
6068
6069 /* Now and again we want to expand a string and be sure that the result is in a
6070 new bit of store. This function does that.
6071
6072 Argument: the string to be expanded
6073 Returns:  the expanded string, always in a new bit of store, or NULL
6074 */
6075
6076 uschar *
6077 expand_string_copy(uschar *string)
6078 {
6079 uschar *yield = expand_string(string);
6080 if (yield == string) yield = string_copy(string);
6081 return yield;
6082 }
6083
6084
6085
6086 /*************************************************
6087 *        Expand and interpret as an integer      *
6088 *************************************************/
6089
6090 /* Expand a string, and convert the result into an integer.
6091
6092 Arguments:
6093   string  the string to be expanded
6094   isplus  TRUE if a non-negative number is expected
6095
6096 Returns:  the integer value, or
6097           -1 for an expansion error               ) in both cases, message in
6098           -2 for an integer interpretation error  ) expand_string_message
6099           expand_string_message is set NULL for an OK integer
6100 */
6101
6102 int
6103 expand_string_integer(uschar *string, BOOL isplus)
6104 {
6105 long int value;
6106 uschar *s = expand_string(string);
6107 uschar *msg = US"invalid integer \"%s\"";
6108 uschar *endptr;
6109
6110 /* If expansion failed, expand_string_message will be set. */
6111
6112 if (s == NULL) return -1;
6113
6114 /* On an overflow, strtol() returns LONG_MAX or LONG_MIN, and sets errno
6115 to ERANGE. When there isn't an overflow, errno is not changed, at least on some
6116 systems, so we set it zero ourselves. */
6117
6118 errno = 0;
6119 expand_string_message = NULL;               /* Indicates no error */
6120
6121 /* Before Exim 4.64, strings consisting entirely of whitespace compared
6122 equal to 0.  Unfortunately, people actually relied upon that, so preserve
6123 the behaviour explicitly.  Stripping leading whitespace is a harmless
6124 noop change since strtol skips it anyway (provided that there is a number
6125 to find at all). */
6126 if (isspace(*s))
6127   {
6128   while (isspace(*s)) ++s;
6129   if (*s == '\0')
6130     {
6131       DEBUG(D_expand)
6132        debug_printf("treating blank string as number 0\n");
6133       return 0;
6134     }
6135   }
6136
6137 value = strtol(CS s, CSS &endptr, 10);
6138
6139 if (endptr == s)
6140   {
6141   msg = US"integer expected but \"%s\" found";
6142   }
6143 else if (value < 0 && isplus)
6144   {
6145   msg = US"non-negative integer expected but \"%s\" found";
6146   }
6147 else
6148   {
6149   /* Ensure we can cast this down to an int */
6150   if (value > INT_MAX  || value < INT_MIN) errno = ERANGE;
6151
6152   if (errno != ERANGE)
6153     {
6154     if (tolower(*endptr) == 'k')
6155       {
6156       if (value > INT_MAX/1024 || value < INT_MIN/1024) errno = ERANGE;
6157         else value *= 1024;
6158       endptr++;
6159       }
6160     else if (tolower(*endptr) == 'm')
6161       {
6162       if (value > INT_MAX/(1024*1024) || value < INT_MIN/(1024*1024))
6163         errno = ERANGE;
6164       else value *= 1024*1024;
6165       endptr++;
6166       }
6167     }
6168   if (errno == ERANGE)
6169     msg = US"absolute value of integer \"%s\" is too large (overflow)";
6170   else
6171     {
6172     while (isspace(*endptr)) endptr++;
6173     if (*endptr == 0) return (int)value;
6174     }
6175   }
6176
6177 expand_string_message = string_sprintf(CS msg, s);
6178 return -2;
6179 }
6180
6181
6182 /*************************************************
6183 **************************************************
6184 *             Stand-alone test program           *
6185 **************************************************
6186 *************************************************/
6187
6188 #ifdef STAND_ALONE
6189
6190
6191 BOOL
6192 regex_match_and_setup(const pcre *re, uschar *subject, int options, int setup)
6193 {
6194 int ovector[3*(EXPAND_MAXN+1)];
6195 int n = pcre_exec(re, NULL, subject, Ustrlen(subject), 0, PCRE_EOPT|options,
6196   ovector, sizeof(ovector)/sizeof(int));
6197 BOOL yield = n >= 0;
6198 if (n == 0) n = EXPAND_MAXN + 1;
6199 if (yield)
6200   {
6201   int nn;
6202   expand_nmax = (setup < 0)? 0 : setup + 1;
6203   for (nn = (setup < 0)? 0 : 2; nn < n*2; nn += 2)
6204     {
6205     expand_nstring[expand_nmax] = subject + ovector[nn];
6206     expand_nlength[expand_nmax++] = ovector[nn+1] - ovector[nn];
6207     }
6208   expand_nmax--;
6209   }
6210 return yield;
6211 }
6212
6213
6214 int main(int argc, uschar **argv)
6215 {
6216 int i;
6217 uschar buffer[1024];
6218
6219 debug_selector = D_v;
6220 debug_file = stderr;
6221 debug_fd = fileno(debug_file);
6222 big_buffer = malloc(big_buffer_size);
6223
6224 for (i = 1; i < argc; i++)
6225   {
6226   if (argv[i][0] == '+')
6227     {
6228     debug_trace_memory = 2;
6229     argv[i]++;
6230     }
6231   if (isdigit(argv[i][0]))
6232     debug_selector = Ustrtol(argv[i], NULL, 0);
6233   else
6234     if (Ustrspn(argv[i], "abcdefghijklmnopqrtsuvwxyz0123456789-.:/") ==
6235         Ustrlen(argv[i]))
6236       {
6237       #ifdef LOOKUP_LDAP
6238       eldap_default_servers = argv[i];
6239       #endif
6240       #ifdef LOOKUP_MYSQL
6241       mysql_servers = argv[i];
6242       #endif
6243       #ifdef LOOKUP_PGSQL
6244       pgsql_servers = argv[i];
6245       #endif
6246       }
6247   #ifdef EXIM_PERL
6248   else opt_perl_startup = argv[i];
6249   #endif
6250   }
6251
6252 printf("Testing string expansion: debug_level = %d\n\n", debug_level);
6253
6254 expand_nstring[1] = US"string 1....";
6255 expand_nlength[1] = 8;
6256 expand_nmax = 1;
6257
6258 #ifdef EXIM_PERL
6259 if (opt_perl_startup != NULL)
6260   {
6261   uschar *errstr;
6262   printf("Starting Perl interpreter\n");
6263   errstr = init_perl(opt_perl_startup);
6264   if (errstr != NULL)
6265     {
6266     printf("** error in perl_startup code: %s\n", errstr);
6267     return EXIT_FAILURE;
6268     }
6269   }
6270 #endif /* EXIM_PERL */
6271
6272 while (fgets(buffer, sizeof(buffer), stdin) != NULL)
6273   {
6274   void *reset_point = store_get(0);
6275   uschar *yield = expand_string(buffer);
6276   if (yield != NULL)
6277     {
6278     printf("%s\n", yield);
6279     store_reset(reset_point);
6280     }
6281   else
6282     {
6283     if (search_find_defer) printf("search_find deferred\n");
6284     printf("Failed: %s\n", expand_string_message);
6285     if (expand_string_forcedfail) printf("Forced failure\n");
6286     printf("\n");
6287     }
6288   }
6289
6290 search_tidyup();
6291
6292 return 0;
6293 }
6294
6295 #endif
6296
6297 /* End of expand.c */