src/src/expand.c

   1 /* $Cambridge: exim/src/src/expand.c,v 1.89 2007/08/22 10:10:23 ph10 Exp $ */
   2
   3 /*************************************************
   4 *     Exim - an Internet mail transport agent    *
   5 *************************************************/
   6
   7 /* Copyright (c) University of Cambridge 1995 - 2007 */
   8 /* See the file NOTICE for conditions of use and distribution. */
   9
  10
  11 /* Functions for handling string expansion. */
  12
  13
  14 #include "exim.h"
  15
  16 /* Recursively called function */
  17
  18 static uschar *expand_string_internal(uschar *, BOOL, uschar **, BOOL);
  19
  20 #ifdef STAND_ALONE
  21 #ifndef SUPPORT_CRYPTEQ
  22 #define SUPPORT_CRYPTEQ
  23 #endif
  24 #endif
  25
  26 #ifdef LOOKUP_LDAP
  27 #include "lookups/ldap.h"
  28 #endif
  29
  30 #ifdef SUPPORT_CRYPTEQ
  31 #ifdef CRYPT_H
  32 #include <crypt.h>
  33 #endif
  34 #ifndef HAVE_CRYPT16
  35 extern char* crypt16(char*, char*);
  36 #endif
  37 #endif
  38
  39 /* The handling of crypt16() is a mess. I will record below the analysis of the
  40 mess that was sent to me. We decided, however, to make changing this very low
  41 priority, because in practice people are moving away from the crypt()
  42 algorithms nowadays, so it doesn't seem worth it.
  43
  44 <quote>
  45 There is an algorithm named "crypt16" in Ultrix and Tru64.  It crypts
  46 the first 8 characters of the password using a 20-round version of crypt
  47 (standard crypt does 25 rounds).  It then crypts the next 8 characters,
  48 or an empty block if the password is less than 9 characters, using a
  49 20-round version of crypt and the same salt as was used for the first
  50 block.  Charaters after the first 16 are ignored.  It always generates
  51 a 16-byte hash, which is expressed together with the salt as a string
  52 of 24 base 64 digits.  Here are some links to peruse:
  53
  54         http://cvs.pld.org.pl/pam/pamcrypt/crypt16.c?rev=1.2
  55         http://seclists.org/bugtraq/1999/Mar/0076.html
  56
  57 There's a different algorithm named "bigcrypt" in HP-UX, Digital Unix,
  58 and OSF/1.  This is the same as the standard crypt if given a password
  59 of 8 characters or less.  If given more, it first does the same as crypt
  60 using the first 8 characters, then crypts the next 8 (the 9th to 16th)
  61 using as salt the first two base 64 digits from the first hash block.
  62 If the password is more than 16 characters then it crypts the 17th to 24th
  63 characters using as salt the first two base 64 digits from the second hash
  64 block.  And so on: I've seen references to it cutting off the password at
  65 40 characters (5 blocks), 80 (10 blocks), or 128 (16 blocks).  Some links:
  66
  67         http://cvs.pld.org.pl/pam/pamcrypt/bigcrypt.c?rev=1.2
  68         http://seclists.org/bugtraq/1999/Mar/0109.html
  69         http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/HTML/AA-Q0R2D-
  70              TET1_html/sec.c222.html#no_id_208
  71
  72 Exim has something it calls "crypt16".  It will either use a native
  73 crypt16 or its own implementation.  A native crypt16 will presumably
  74 be the one that I called "crypt16" above.  The internal "crypt16"
  75 function, however, is a two-block-maximum implementation of what I called
  76 "bigcrypt".  The documentation matches the internal code.
  77
  78 I suspect that whoever did the "crypt16" stuff for Exim didn't realise
  79 that crypt16 and bigcrypt were different things.
  80
  81 Exim uses the LDAP-style scheme identifier "{crypt16}" to refer
  82 to whatever it is using under that name.  This unfortunately sets a
  83 precedent for using "{crypt16}" to identify two incompatible algorithms
  84 whose output can't be distinguished.  With "{crypt16}" thus rendered
  85 ambiguous, I suggest you deprecate it and invent two new identifiers
  86 for the two algorithms.
  87
  88 Both crypt16 and bigcrypt are very poor algorithms, btw.  Hashing parts
  89 of the password separately means they can be cracked separately, so
  90 the double-length hash only doubles the cracking effort instead of
  91 squaring it.  I recommend salted SHA-1 ({SSHA}), or the Blowfish-based
  92 bcrypt ({CRYPT}$2a$).
  93 </quote>
  94 */
  95
  96
  97
  98
  99 /*************************************************
 100 *            Local statics and tables            *
 101 *************************************************/
 102
 103 /* Table of item names, and corresponding switch numbers. The names must be in
 104 alphabetical order. */
 105
 106 static uschar *item_table[] = {
 107   US"dlfunc",
 108   US"extract",
 109   US"filter",
 110   US"hash",
 111   US"hmac",
 112   US"if",
 113   US"length",
 114   US"lookup",
 115   US"map",
 116   US"nhash",
 117   US"perl",
 118   US"prvs",
 119   US"prvscheck",
 120   US"readfile",
 121   US"readsocket",
 122   US"reduce",
 123   US"run",
 124   US"sg",
 125   US"substr",
 126   US"tr" };
 127
 128 enum {
 129   EITEM_DLFUNC,
 130   EITEM_EXTRACT,
 131   EITEM_FILTER,
 132   EITEM_HASH,
 133   EITEM_HMAC,
 134   EITEM_IF,
 135   EITEM_LENGTH,
 136   EITEM_LOOKUP,
 137   EITEM_MAP,
 138   EITEM_NHASH,
 139   EITEM_PERL,
 140   EITEM_PRVS,
 141   EITEM_PRVSCHECK,
 142   EITEM_READFILE,
 143   EITEM_READSOCK,
 144   EITEM_REDUCE,
 145   EITEM_RUN,
 146   EITEM_SG,
 147   EITEM_SUBSTR,
 148   EITEM_TR };
 149
 150 /* Tables of operator names, and corresponding switch numbers. The names must be
 151 in alphabetical order. There are two tables, because underscore is used in some
 152 cases to introduce arguments, whereas for other it is part of the name. This is
 153 an historical mis-design. */
 154
 155 static uschar *op_table_underscore[] = {
 156   US"from_utf8",
 157   US"local_part",
 158   US"quote_local_part",
 159   US"time_eval",
 160   US"time_interval"};
 161
 162 enum {
 163   EOP_FROM_UTF8,
 164   EOP_LOCAL_PART,
 165   EOP_QUOTE_LOCAL_PART,
 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"rfc2047",
 191   US"rfc2047d",
 192   US"rxquote",
 193   US"s",
 194   US"sha1",
 195   US"stat",
 196   US"str2b64",
 197   US"strlen",
 198   US"substr",
 199   US"uc" };
 200
 201 enum {
 202   EOP_ADDRESS =  sizeof(op_table_underscore)/sizeof(uschar *),
 203   EOP_ADDRESSES,
 204   EOP_BASE62,
 205   EOP_BASE62D,
 206   EOP_DOMAIN,
 207   EOP_ESCAPE,
 208   EOP_EVAL,
 209   EOP_EVAL10,
 210   EOP_EXPAND,
 211   EOP_H,
 212   EOP_HASH,
 213   EOP_HEX2B64,
 214   EOP_L,
 215   EOP_LC,
 216   EOP_LENGTH,
 217   EOP_MASK,
 218   EOP_MD5,
 219   EOP_NH,
 220   EOP_NHASH,
 221   EOP_QUOTE,
 222   EOP_RFC2047,
 223   EOP_RFC2047D,
 224   EOP_RXQUOTE,
 225   EOP_S,
 226   EOP_SHA1,
 227   EOP_STAT,
 228   EOP_STR2B64,
 229   EOP_STRLEN,
 230   EOP_SUBSTR,
 231   EOP_UC };
 232
 233
 234 /* Table of condition names, and corresponding switch numbers. The names must
 235 be in alphabetical order. */
 236
 237 static uschar *cond_table[] = {
 238   US"<",
 239   US"<=",
 240   US"=",
 241   US"==",     /* Backward compatibility */
 242   US">",
 243   US">=",
 244   US"and",
 245   US"crypteq",
 246   US"def",
 247   US"eq",
 248   US"eqi",
 249   US"exists",
 250   US"first_delivery",
 251   US"forall",
 252   US"forany",
 253   US"ge",
 254   US"gei",
 255   US"gt",
 256   US"gti",
 257   US"isip",
 258   US"isip4",
 259   US"isip6",
 260   US"ldapauth",
 261   US"le",
 262   US"lei",
 263   US"lt",
 264   US"lti",
 265   US"match",
 266   US"match_address",
 267   US"match_domain",
 268   US"match_ip",
 269   US"match_local_part",
 270   US"or",
 271   US"pam",
 272   US"pwcheck",
 273   US"queue_running",
 274   US"radius",
 275   US"saslauthd"
 276 };
 277
 278 enum {
 279   ECOND_NUM_L,
 280   ECOND_NUM_LE,
 281   ECOND_NUM_E,
 282   ECOND_NUM_EE,
 283   ECOND_NUM_G,
 284   ECOND_NUM_GE,
 285   ECOND_AND,
 286   ECOND_CRYPTEQ,
 287   ECOND_DEF,
 288   ECOND_STR_EQ,
 289   ECOND_STR_EQI,
 290   ECOND_EXISTS,
 291   ECOND_FIRST_DELIVERY,
 292   ECOND_FORALL,
 293   ECOND_FORANY,
 294   ECOND_STR_GE,
 295   ECOND_STR_GEI,
 296   ECOND_STR_GT,
 297   ECOND_STR_GTI,
 298   ECOND_ISIP,
 299   ECOND_ISIP4,
 300   ECOND_ISIP6,
 301   ECOND_LDAPAUTH,
 302   ECOND_STR_LE,
 303   ECOND_STR_LEI,
 304   ECOND_STR_LT,
 305   ECOND_STR_LTI,
 306   ECOND_MATCH,
 307   ECOND_MATCH_ADDRESS,
 308   ECOND_MATCH_DOMAIN,
 309   ECOND_MATCH_IP,
 310   ECOND_MATCH_LOCAL_PART,
 311   ECOND_OR,
 312   ECOND_PAM,
 313   ECOND_PWCHECK,
 314   ECOND_QUEUE_RUNNING,
 315   ECOND_RADIUS,
 316   ECOND_SASLAUTHD
 317 };
 318
 319
 320 /* Type for main variable table */
 321
 322 typedef struct {
 323   char *name;
 324   int   type;
 325   void *value;
 326 } var_entry;
 327
 328 /* Type for entries pointing to address/length pairs. Not currently
 329 in use. */
 330
 331 typedef struct {
 332   uschar **address;
 333   int  *length;
 334 } alblock;
 335
 336 /* Types of table entry */
 337
 338 enum {
 339   vtype_int,            /* value is address of int */
 340   vtype_filter_int,     /* ditto, but recognized only when filtering */
 341   vtype_ino,            /* value is address of ino_t (not always an int) */
 342   vtype_uid,            /* value is address of uid_t (not always an int) */
 343   vtype_gid,            /* value is address of gid_t (not always an int) */
 344   vtype_stringptr,      /* value is address of pointer to string */
 345   vtype_msgbody,        /* as stringptr, but read when first required */
 346   vtype_msgbody_end,    /* ditto, the end of the message */
 347   vtype_msgheaders,     /* the message's headers, processed */
 348   vtype_msgheaders_raw, /* the message's headers, unprocessed */
 349   vtype_localpart,      /* extract local part from string */
 350   vtype_domain,         /* extract domain from string */
 351   vtype_recipients,     /* extract recipients from recipients list */
 352                         /* (available only in system filters, ACLs, and */
 353                         /* local_scan()) */
 354   vtype_todbsdin,       /* value not used; generate BSD inbox tod */
 355   vtype_tode,           /* value not used; generate tod in epoch format */
 356   vtype_todf,           /* value not used; generate full tod */
 357   vtype_todl,           /* value not used; generate log tod */
 358   vtype_todlf,          /* value not used; generate log file datestamp tod */
 359   vtype_todzone,        /* value not used; generate time zone only */
 360   vtype_todzulu,        /* value not used; generate zulu tod */
 361   vtype_reply,          /* value not used; get reply from headers */
 362   vtype_pid,            /* value not used; result is pid */
 363   vtype_host_lookup,    /* value not used; get host name */
 364   vtype_load_avg,       /* value not used; result is int from os_getloadavg */
 365   vtype_pspace,         /* partition space; value is T/F for spool/log */
 366   vtype_pinodes         /* partition inodes; value is T/F for spool/log */
 367 #ifdef EXPERIMENTAL_DOMAINKEYS
 368  ,vtype_dk_verify       /* Serve request out of DomainKeys verification structure */
 369 #endif
 370   };
 371
 372 /* This table must be kept in alphabetical order. */
 373
 374 static var_entry var_table[] = {
 375   /* WARNING: Do not invent variables whose names start acl_c or acl_m because
 376      they will be confused with user-creatable ACL variables. */
 377   { "acl_verify_message",  vtype_stringptr,   &acl_verify_message },
 378   { "address_data",        vtype_stringptr,   &deliver_address_data },
 379   { "address_file",        vtype_stringptr,   &address_file },
 380   { "address_pipe",        vtype_stringptr,   &address_pipe },
 381   { "authenticated_id",    vtype_stringptr,   &authenticated_id },
 382   { "authenticated_sender",vtype_stringptr,   &authenticated_sender },
 383   { "authentication_failed",vtype_int,        &authentication_failed },
 384 #ifdef EXPERIMENTAL_BRIGHTMAIL
 385   { "bmi_alt_location",    vtype_stringptr,   &bmi_alt_location },
 386   { "bmi_base64_tracker_verdict", vtype_stringptr, &bmi_base64_tracker_verdict },
 387   { "bmi_base64_verdict",  vtype_stringptr,   &bmi_base64_verdict },
 388   { "bmi_deliver",         vtype_int,         &bmi_deliver },
 389 #endif
 390   { "body_linecount",      vtype_int,         &body_linecount },
 391   { "body_zerocount",      vtype_int,         &body_zerocount },
 392   { "bounce_recipient",    vtype_stringptr,   &bounce_recipient },
 393   { "bounce_return_size_limit", vtype_int,    &bounce_return_size_limit },
 394   { "caller_gid",          vtype_gid,         &real_gid },
 395   { "caller_uid",          vtype_uid,         &real_uid },
 396   { "compile_date",        vtype_stringptr,   &version_date },
 397   { "compile_number",      vtype_stringptr,   &version_cnumber },
 398   { "csa_status",          vtype_stringptr,   &csa_status },
 399 #ifdef WITH_OLD_DEMIME
 400   { "demime_errorlevel",   vtype_int,         &demime_errorlevel },
 401   { "demime_reason",       vtype_stringptr,   &demime_reason },
 402 #endif
 403 #ifdef EXPERIMENTAL_DOMAINKEYS
 404   { "dk_domain",           vtype_stringptr,   &dk_signing_domain },
 405   { "dk_is_signed",        vtype_dk_verify,   NULL },
 406   { "dk_result",           vtype_dk_verify,   NULL },
 407   { "dk_selector",         vtype_stringptr,   &dk_signing_selector },
 408   { "dk_sender",           vtype_dk_verify,   NULL },
 409   { "dk_sender_domain",    vtype_dk_verify,   NULL },
 410   { "dk_sender_local_part",vtype_dk_verify,   NULL },
 411   { "dk_sender_source",    vtype_dk_verify,   NULL },
 412   { "dk_signsall",         vtype_dk_verify,   NULL },
 413   { "dk_status",           vtype_dk_verify,   NULL },
 414   { "dk_testing",          vtype_dk_verify,   NULL },
 415 #endif
 416   { "dnslist_domain",      vtype_stringptr,   &dnslist_domain },
 417   { "dnslist_matched",     vtype_stringptr,   &dnslist_matched },
 418   { "dnslist_text",        vtype_stringptr,   &dnslist_text },
 419   { "dnslist_value",       vtype_stringptr,   &dnslist_value },
 420   { "domain",              vtype_stringptr,   &deliver_domain },
 421   { "domain_data",         vtype_stringptr,   &deliver_domain_data },
 422   { "exim_gid",            vtype_gid,         &exim_gid },
 423   { "exim_path",           vtype_stringptr,   &exim_path },
 424   { "exim_uid",            vtype_uid,         &exim_uid },
 425 #ifdef WITH_OLD_DEMIME
 426   { "found_extension",     vtype_stringptr,   &found_extension },
 427 #endif
 428   { "home",                vtype_stringptr,   &deliver_home },
 429   { "host",                vtype_stringptr,   &deliver_host },
 430   { "host_address",        vtype_stringptr,   &deliver_host_address },
 431   { "host_data",           vtype_stringptr,   &host_data },
 432   { "host_lookup_deferred",vtype_int,         &host_lookup_deferred },
 433   { "host_lookup_failed",  vtype_int,         &host_lookup_failed },
 434   { "inode",               vtype_ino,         &deliver_inode },
 435   { "interface_address",   vtype_stringptr,   &interface_address },
 436   { "interface_port",      vtype_int,         &interface_port },
 437   { "item",                vtype_stringptr,   &iterate_item },
 438   #ifdef LOOKUP_LDAP
 439   { "ldap_dn",             vtype_stringptr,   &eldap_dn },
 440   #endif
 441   { "load_average",        vtype_load_avg,    NULL },
 442   { "local_part",          vtype_stringptr,   &deliver_localpart },
 443   { "local_part_data",     vtype_stringptr,   &deliver_localpart_data },
 444   { "local_part_prefix",   vtype_stringptr,   &deliver_localpart_prefix },
 445   { "local_part_suffix",   vtype_stringptr,   &deliver_localpart_suffix },
 446   { "local_scan_data",     vtype_stringptr,   &local_scan_data },
 447   { "local_user_gid",      vtype_gid,         &local_user_gid },
 448   { "local_user_uid",      vtype_uid,         &local_user_uid },
 449   { "localhost_number",    vtype_int,         &host_number },
 450   { "log_inodes",          vtype_pinodes,     (void *)FALSE },
 451   { "log_space",           vtype_pspace,      (void *)FALSE },
 452   { "mailstore_basename",  vtype_stringptr,   &mailstore_basename },
 453 #ifdef WITH_CONTENT_SCAN
 454   { "malware_name",        vtype_stringptr,   &malware_name },
 455 #endif
 456   { "max_received_linelength", vtype_int,     &max_received_linelength },
 457   { "message_age",         vtype_int,         &message_age },
 458   { "message_body",        vtype_msgbody,     &message_body },
 459   { "message_body_end",    vtype_msgbody_end, &message_body_end },
 460   { "message_body_size",   vtype_int,         &message_body_size },
 461   { "message_exim_id",     vtype_stringptr,   &message_id },
 462   { "message_headers",     vtype_msgheaders,  NULL },
 463   { "message_headers_raw", vtype_msgheaders_raw, NULL },
 464   { "message_id",          vtype_stringptr,   &message_id },
 465   { "message_linecount",   vtype_int,         &message_linecount },
 466   { "message_size",        vtype_int,         &message_size },
 467 #ifdef WITH_CONTENT_SCAN
 468   { "mime_anomaly_level",  vtype_int,         &mime_anomaly_level },
 469   { "mime_anomaly_text",   vtype_stringptr,   &mime_anomaly_text },
 470   { "mime_boundary",       vtype_stringptr,   &mime_boundary },
 471   { "mime_charset",        vtype_stringptr,   &mime_charset },
 472   { "mime_content_description", vtype_stringptr, &mime_content_description },
 473   { "mime_content_disposition", vtype_stringptr, &mime_content_disposition },
 474   { "mime_content_id",     vtype_stringptr,   &mime_content_id },
 475   { "mime_content_size",   vtype_int,         &mime_content_size },
 476   { "mime_content_transfer_encoding",vtype_stringptr, &mime_content_transfer_encoding },
 477   { "mime_content_type",   vtype_stringptr,   &mime_content_type },
 478   { "mime_decoded_filename", vtype_stringptr, &mime_decoded_filename },
 479   { "mime_filename",       vtype_stringptr,   &mime_filename },
 480   { "mime_is_coverletter", vtype_int,         &mime_is_coverletter },
 481   { "mime_is_multipart",   vtype_int,         &mime_is_multipart },
 482   { "mime_is_rfc822",      vtype_int,         &mime_is_rfc822 },
 483   { "mime_part_count",     vtype_int,         &mime_part_count },
 484 #endif
 485   { "n0",                  vtype_filter_int,  &filter_n[0] },
 486   { "n1",                  vtype_filter_int,  &filter_n[1] },
 487   { "n2",                  vtype_filter_int,  &filter_n[2] },
 488   { "n3",                  vtype_filter_int,  &filter_n[3] },
 489   { "n4",                  vtype_filter_int,  &filter_n[4] },
 490   { "n5",                  vtype_filter_int,  &filter_n[5] },
 491   { "n6",                  vtype_filter_int,  &filter_n[6] },
 492   { "n7",                  vtype_filter_int,  &filter_n[7] },
 493   { "n8",                  vtype_filter_int,  &filter_n[8] },
 494   { "n9",                  vtype_filter_int,  &filter_n[9] },
 495   { "original_domain",     vtype_stringptr,   &deliver_domain_orig },
 496   { "original_local_part", vtype_stringptr,   &deliver_localpart_orig },
 497   { "originator_gid",      vtype_gid,         &originator_gid },
 498   { "originator_uid",      vtype_uid,         &originator_uid },
 499   { "parent_domain",       vtype_stringptr,   &deliver_domain_parent },
 500   { "parent_local_part",   vtype_stringptr,   &deliver_localpart_parent },
 501   { "pid",                 vtype_pid,         NULL },
 502   { "primary_hostname",    vtype_stringptr,   &primary_hostname },
 503   { "prvscheck_address",   vtype_stringptr,   &prvscheck_address },
 504   { "prvscheck_keynum",    vtype_stringptr,   &prvscheck_keynum },
 505   { "prvscheck_result",    vtype_stringptr,   &prvscheck_result },
 506   { "qualify_domain",      vtype_stringptr,   &qualify_domain_sender },
 507   { "qualify_recipient",   vtype_stringptr,   &qualify_domain_recipient },
 508   { "rcpt_count",          vtype_int,         &rcpt_count },
 509   { "rcpt_defer_count",    vtype_int,         &rcpt_defer_count },
 510   { "rcpt_fail_count",     vtype_int,         &rcpt_fail_count },
 511   { "received_count",      vtype_int,         &received_count },
 512   { "received_for",        vtype_stringptr,   &received_for },
 513   { "received_ip_address", vtype_stringptr,   &interface_address },
 514   { "received_port",       vtype_int,         &interface_port },
 515   { "received_protocol",   vtype_stringptr,   &received_protocol },
 516   { "received_time",       vtype_int,         &received_time },
 517   { "recipient_data",      vtype_stringptr,   &recipient_data },
 518   { "recipient_verify_failure",vtype_stringptr,&recipient_verify_failure },
 519   { "recipients",          vtype_recipients,  NULL },
 520   { "recipients_count",    vtype_int,         &recipients_count },
 521 #ifdef WITH_CONTENT_SCAN
 522   { "regex_match_string",  vtype_stringptr,   &regex_match_string },
 523 #endif
 524   { "reply_address",       vtype_reply,       NULL },
 525   { "return_path",         vtype_stringptr,   &return_path },
 526   { "return_size_limit",   vtype_int,         &bounce_return_size_limit },
 527   { "runrc",               vtype_int,         &runrc },
 528   { "self_hostname",       vtype_stringptr,   &self_hostname },
 529   { "sender_address",      vtype_stringptr,   &sender_address },
 530   { "sender_address_data", vtype_stringptr,   &sender_address_data },
 531   { "sender_address_domain", vtype_domain,    &sender_address },
 532   { "sender_address_local_part", vtype_localpart, &sender_address },
 533   { "sender_data",         vtype_stringptr,   &sender_data },
 534   { "sender_fullhost",     vtype_stringptr,   &sender_fullhost },
 535   { "sender_helo_name",    vtype_stringptr,   &sender_helo_name },
 536   { "sender_host_address", vtype_stringptr,   &sender_host_address },
 537   { "sender_host_authenticated",vtype_stringptr, &sender_host_authenticated },
 538   { "sender_host_name",    vtype_host_lookup, NULL },
 539   { "sender_host_port",    vtype_int,         &sender_host_port },
 540   { "sender_ident",        vtype_stringptr,   &sender_ident },
 541   { "sender_rate",         vtype_stringptr,   &sender_rate },
 542   { "sender_rate_limit",   vtype_stringptr,   &sender_rate_limit },
 543   { "sender_rate_period",  vtype_stringptr,   &sender_rate_period },
 544   { "sender_rcvhost",      vtype_stringptr,   &sender_rcvhost },
 545   { "sender_verify_failure",vtype_stringptr,  &sender_verify_failure },
 546   { "sending_ip_address",  vtype_stringptr,   &sending_ip_address },
 547   { "sending_port",        vtype_int,         &sending_port },
 548   { "smtp_active_hostname", vtype_stringptr,  &smtp_active_hostname },
 549   { "smtp_command",        vtype_stringptr,   &smtp_cmd_buffer },
 550   { "smtp_command_argument", vtype_stringptr, &smtp_cmd_argument },
 551   { "smtp_count_at_connection_start", vtype_int, &smtp_accept_count },
 552   { "smtp_notquit_reason", vtype_stringptr,   &smtp_notquit_reason },
 553   { "sn0",                 vtype_filter_int,  &filter_sn[0] },
 554   { "sn1",                 vtype_filter_int,  &filter_sn[1] },
 555   { "sn2",                 vtype_filter_int,  &filter_sn[2] },
 556   { "sn3",                 vtype_filter_int,  &filter_sn[3] },
 557   { "sn4",                 vtype_filter_int,  &filter_sn[4] },
 558   { "sn5",                 vtype_filter_int,  &filter_sn[5] },
 559   { "sn6",                 vtype_filter_int,  &filter_sn[6] },
 560   { "sn7",                 vtype_filter_int,  &filter_sn[7] },
 561   { "sn8",                 vtype_filter_int,  &filter_sn[8] },
 562   { "sn9",                 vtype_filter_int,  &filter_sn[9] },
 563 #ifdef WITH_CONTENT_SCAN
 564   { "spam_bar",            vtype_stringptr,   &spam_bar },
 565   { "spam_report",         vtype_stringptr,   &spam_report },
 566   { "spam_score",          vtype_stringptr,   &spam_score },
 567   { "spam_score_int",      vtype_stringptr,   &spam_score_int },
 568 #endif
 569 #ifdef EXPERIMENTAL_SPF
 570   { "spf_header_comment",  vtype_stringptr,   &spf_header_comment },
 571   { "spf_received",        vtype_stringptr,   &spf_received },
 572   { "spf_result",          vtype_stringptr,   &spf_result },
 573   { "spf_smtp_comment",    vtype_stringptr,   &spf_smtp_comment },
 574 #endif
 575   { "spool_directory",     vtype_stringptr,   &spool_directory },
 576   { "spool_inodes",        vtype_pinodes,     (void *)TRUE },
 577   { "spool_space",         vtype_pspace,      (void *)TRUE },
 578 #ifdef EXPERIMENTAL_SRS
 579   { "srs_db_address",      vtype_stringptr,   &srs_db_address },
 580   { "srs_db_key",          vtype_stringptr,   &srs_db_key },
 581   { "srs_orig_recipient",  vtype_stringptr,   &srs_orig_recipient },
 582   { "srs_orig_sender",     vtype_stringptr,   &srs_orig_sender },
 583   { "srs_recipient",       vtype_stringptr,   &srs_recipient },
 584   { "srs_status",          vtype_stringptr,   &srs_status },
 585 #endif
 586   { "thisaddress",         vtype_stringptr,   &filter_thisaddress },
 587   { "tls_certificate_verified", vtype_int,    &tls_certificate_verified },
 588   { "tls_cipher",          vtype_stringptr,   &tls_cipher },
 589   { "tls_peerdn",          vtype_stringptr,   &tls_peerdn },
 590   { "tod_bsdinbox",        vtype_todbsdin,    NULL },
 591   { "tod_epoch",           vtype_tode,        NULL },
 592   { "tod_full",            vtype_todf,        NULL },
 593   { "tod_log",             vtype_todl,        NULL },
 594   { "tod_logfile",         vtype_todlf,       NULL },
 595   { "tod_zone",            vtype_todzone,     NULL },
 596   { "tod_zulu",            vtype_todzulu,     NULL },
 597   { "value",               vtype_stringptr,   &lookup_value },
 598   { "version_number",      vtype_stringptr,   &version_string },
 599   { "warn_message_delay",  vtype_stringptr,   &warnmsg_delay },
 600   { "warn_message_recipient",vtype_stringptr, &warnmsg_recipients },
 601   { "warn_message_recipients",vtype_stringptr,&warnmsg_recipients },
 602   { "warnmsg_delay",       vtype_stringptr,   &warnmsg_delay },
 603   { "warnmsg_recipient",   vtype_stringptr,   &warnmsg_recipients },
 604   { "warnmsg_recipients",  vtype_stringptr,   &warnmsg_recipients }
 605 };
 606
 607 static int var_table_size = sizeof(var_table)/sizeof(var_entry);
 608 static uschar var_buffer[256];
 609 static BOOL malformed_header;
 610
 611 /* For textual hashes */
 612
 613 static char *hashcodes = "abcdefghijklmnopqrtsuvwxyz"
 614                          "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 615                          "0123456789";
 616
 617 enum { HMAC_MD5, HMAC_SHA1 };
 618
 619 /* For numeric hashes */
 620
 621 static unsigned int prime[] = {
 622   2,   3,   5,   7,  11,  13,  17,  19,  23,  29,
 623  31,  37,  41,  43,  47,  53,  59,  61,  67,  71,
 624  73,  79,  83,  89,  97, 101, 103, 107, 109, 113};
 625
 626 /* For printing modes in symbolic form */
 627
 628 static uschar *mtable_normal[] =
 629   { US"---", US"--x", US"-w-", US"-wx", US"r--", US"r-x", US"rw-", US"rwx" };
 630
 631 static uschar *mtable_setid[] =
 632   { US"--S", US"--s", US"-wS", US"-ws", US"r-S", US"r-s", US"rwS", US"rws" };
 633
 634 static uschar *mtable_sticky[] =
 635   { US"--T", US"--t", US"-wT", US"-wt", US"r-T", US"r-t", US"rwT", US"rwt" };
 636
 637
 638
 639 /*************************************************
 640 *           Tables for UTF-8 support             *
 641 *************************************************/
 642
 643 /* Table of the number of extra characters, indexed by the first character
 644 masked with 0x3f. The highest number for a valid UTF-8 character is in fact
 645 0x3d. */
 646
 647 static uschar utf8_table1[] = {
 648   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 649   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 650   2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
 651   3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5 };
 652
 653 /* These are the masks for the data bits in the first byte of a character,
 654 indexed by the number of additional bytes. */
 655
 656 static int utf8_table2[] = { 0xff, 0x1f, 0x0f, 0x07, 0x03, 0x01};
 657
 658 /* Get the next UTF-8 character, advancing the pointer. */
 659
 660 #define GETUTF8INC(c, ptr) \
 661   c = *ptr++; \
 662   if ((c & 0xc0) == 0xc0) \
 663     { \
 664     int a = utf8_table1[c & 0x3f];  /* Number of additional bytes */ \
 665     int s = 6*a; \
 666     c = (c & utf8_table2[a]) << s; \
 667     while (a-- > 0) \
 668       { \
 669       s -= 6; \
 670       c |= (*ptr++ & 0x3f) << s; \
 671       } \
 672     }
 673
 674
 675 /*************************************************
 676 *           Binary chop search on a table        *
 677 *************************************************/
 678
 679 /* This is used for matching expansion items and operators.
 680
 681 Arguments:
 682   name        the name that is being sought
 683   table       the table to search
 684   table_size  the number of items in the table
 685
 686 Returns:      the offset in the table, or -1
 687 */
 688
 689 static int
 690 chop_match(uschar *name, uschar **table, int table_size)
 691 {
 692 uschar **bot = table;
 693 uschar **top = table + table_size;
 694
 695 while (top > bot)
 696   {
 697   uschar **mid = bot + (top - bot)/2;
 698   int c = Ustrcmp(name, *mid);
 699   if (c == 0) return mid - table;
 700   if (c > 0) bot = mid + 1; else top = mid;
 701   }
 702
 703 return -1;
 704 }
 705
 706
 707
 708 /*************************************************
 709 *          Check a condition string              *
 710 *************************************************/
 711
 712 /* This function is called to expand a string, and test the result for a "true"
 713 or "false" value. Failure of the expansion yields FALSE; logged unless it was a
 714 forced fail or lookup defer. All store used by the function can be released on
 715 exit.
 716
 717 Arguments:
 718   condition     the condition string
 719   m1            text to be incorporated in panic error
 720   m2            ditto
 721
 722 Returns:        TRUE if condition is met, FALSE if not
 723 */
 724
 725 BOOL
 726 expand_check_condition(uschar *condition, uschar *m1, uschar *m2)
 727 {
 728 int rc;
 729 void *reset_point = store_get(0);
 730 uschar *ss = expand_string(condition);
 731 if (ss == NULL)
 732   {
 733   if (!expand_string_forcedfail && !search_find_defer)
 734     log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand condition \"%s\" "
 735       "for %s %s: %s", condition, m1, m2, expand_string_message);
 736   return FALSE;
 737   }
 738 rc = ss[0] != 0 && Ustrcmp(ss, "0") != 0 && strcmpic(ss, US"no") != 0 &&
 739   strcmpic(ss, US"false") != 0;
 740 store_reset(reset_point);
 741 return rc;
 742 }
 743
 744
 745
 746 /*************************************************
 747 *             Pick out a name from a string      *
 748 *************************************************/
 749
 750 /* If the name is too long, it is silently truncated.
 751
 752 Arguments:
 753   name      points to a buffer into which to put the name
 754   max       is the length of the buffer
 755   s         points to the first alphabetic character of the name
 756   extras    chars other than alphanumerics to permit
 757
 758 Returns:    pointer to the first character after the name
 759
 760 Note: The test for *s != 0 in the while loop is necessary because
 761 Ustrchr() yields non-NULL if the character is zero (which is not something
 762 I expected). */
 763
 764 static uschar *
 765 read_name(uschar *name, int max, uschar *s, uschar *extras)
 766 {
 767 int ptr = 0;
 768 while (*s != 0 && (isalnum(*s) || Ustrchr(extras, *s) != NULL))
 769   {
 770   if (ptr < max-1) name[ptr++] = *s;
 771   s++;
 772   }
 773 name[ptr] = 0;
 774 return s;
 775 }
 776
 777
 778
 779 /*************************************************
 780 *     Pick out the rest of a header name         *
 781 *************************************************/
 782
 783 /* A variable name starting $header_ (or just $h_ for those who like
 784 abbreviations) might not be the complete header name because headers can
 785 contain any printing characters in their names, except ':'. This function is
 786 called to read the rest of the name, chop h[eader]_ off the front, and put ':'
 787 on the end, if the name was terminated by white space.
 788
 789 Arguments:
 790   name      points to a buffer in which the name read so far exists
 791   max       is the length of the buffer
 792   s         points to the first character after the name so far, i.e. the
 793             first non-alphameric character after $header_xxxxx
 794
 795 Returns:    a pointer to the first character after the header name
 796 */
 797
 798 static uschar *
 799 read_header_name(uschar *name, int max, uschar *s)
 800 {
 801 int prelen = Ustrchr(name, '_') - name + 1;
 802 int ptr = Ustrlen(name) - prelen;
 803 if (ptr > 0) memmove(name, name+prelen, ptr);
 804 while (mac_isgraph(*s) && *s != ':')
 805   {
 806   if (ptr < max-1) name[ptr++] = *s;
 807   s++;
 808   }
 809 if (*s == ':') s++;
 810 name[ptr++] = ':';
 811 name[ptr] = 0;
 812 return s;
 813 }
 814
 815
 816
 817 /*************************************************
 818 *           Pick out a number from a string      *
 819 *************************************************/
 820
 821 /* Arguments:
 822   n     points to an integer into which to put the number
 823   s     points to the first digit of the number
 824
 825 Returns:  a pointer to the character after the last digit
 826 */
 827
 828 static uschar *
 829 read_number(int *n, uschar *s)
 830 {
 831 *n = 0;
 832 while (isdigit(*s)) *n = *n * 10 + (*s++ - '0');
 833 return s;
 834 }
 835
 836
 837
 838 /*************************************************
 839 *        Extract keyed subfield from a string    *
 840 *************************************************/
 841
 842 /* The yield is in dynamic store; NULL means that the key was not found.
 843
 844 Arguments:
 845   key       points to the name of the key
 846   s         points to the string from which to extract the subfield
 847
 848 Returns:    NULL if the subfield was not found, or
 849             a pointer to the subfield's data
 850 */
 851
 852 static uschar *
 853 expand_getkeyed(uschar *key, uschar *s)
 854 {
 855 int length = Ustrlen(key);
 856 while (isspace(*s)) s++;
 857
 858 /* Loop to search for the key */
 859
 860 while (*s != 0)
 861   {
 862   int dkeylength;
 863   uschar *data;
 864   uschar *dkey = s;
 865
 866   while (*s != 0 && *s != '=' && !isspace(*s)) s++;
 867   dkeylength = s - dkey;
 868   while (isspace(*s)) s++;
 869   if (*s == '=') while (isspace((*(++s))));
 870
 871   data = string_dequote(&s);
 872   if (length == dkeylength && strncmpic(key, dkey, length) == 0)
 873     return data;
 874
 875   while (isspace(*s)) s++;
 876   }
 877
 878 return NULL;
 879 }
 880
 881
 882
 883
 884 /*************************************************
 885 *   Extract numbered subfield from string        *
 886 *************************************************/
 887
 888 /* Extracts a numbered field from a string that is divided by tokens - for
 889 example a line from /etc/passwd is divided by colon characters.  First field is
 890 numbered one.  Negative arguments count from the right. Zero returns the whole
 891 string. Returns NULL if there are insufficient tokens in the string
 892
 893 ***WARNING***
 894 Modifies final argument - this is a dynamically generated string, so that's OK.
 895
 896 Arguments:
 897   field       number of field to be extracted,
 898                 first field = 1, whole string = 0, last field = -1
 899   separators  characters that are used to break string into tokens
 900   s           points to the string from which to extract the subfield
 901
 902 Returns:      NULL if the field was not found,
 903               a pointer to the field's data inside s (modified to add 0)
 904 */
 905
 906 static uschar *
 907 expand_gettokened (int field, uschar *separators, uschar *s)
 908 {
 909 int sep = 1;
 910 int count;
 911 uschar *ss = s;
 912 uschar *fieldtext = NULL;
 913
 914 if (field == 0) return s;
 915
 916 /* Break the line up into fields in place; for field > 0 we stop when we have
 917 done the number of fields we want. For field < 0 we continue till the end of
 918 the string, counting the number of fields. */
 919
 920 count = (field > 0)? field : INT_MAX;
 921
 922 while (count-- > 0)
 923   {
 924   size_t len;
 925
 926   /* Previous field was the last one in the string. For a positive field
 927   number, this means there are not enough fields. For a negative field number,
 928   check that there are enough, and scan back to find the one that is wanted. */
 929
 930   if (sep == 0)
 931     {
 932     if (field > 0 || (-field) > (INT_MAX - count - 1)) return NULL;
 933     if ((-field) == (INT_MAX - count - 1)) return s;
 934     while (field++ < 0)
 935       {
 936       ss--;
 937       while (ss[-1] != 0) ss--;
 938       }
 939     fieldtext = ss;
 940     break;
 941     }
 942
 943   /* Previous field was not last in the string; save its start and put a
 944   zero at its end. */
 945
 946   fieldtext = ss;
 947   len = Ustrcspn(ss, separators);
 948   sep = ss[len];
 949   ss[len] = 0;
 950   ss += len + 1;
 951   }
 952
 953 return fieldtext;
 954 }
 955
 956
 957
 958 /*************************************************
 959 *        Extract a substring from a string       *
 960 *************************************************/
 961
 962 /* Perform the ${substr or ${length expansion operations.
 963
 964 Arguments:
 965   subject     the input string
 966   value1      the offset from the start of the input string to the start of
 967                 the output string; if negative, count from the right.
 968   value2      the length of the output string, or negative (-1) for unset
 969                 if value1 is positive, unset means "all after"
 970                 if value1 is negative, unset means "all before"
 971   len         set to the length of the returned string
 972
 973 Returns:      pointer to the output string, or NULL if there is an error
 974 */
 975
 976 static uschar *
 977 extract_substr(uschar *subject, int value1, int value2, int *len)
 978 {
 979 int sublen = Ustrlen(subject);
 980
 981 if (value1 < 0)    /* count from right */
 982   {
 983   value1 += sublen;
 984
 985   /* If the position is before the start, skip to the start, and adjust the
 986   length. If the length ends up negative, the substring is null because nothing
 987   can precede. This falls out naturally when the length is unset, meaning "all
 988   to the left". */
 989
 990   if (value1 < 0)
 991     {
 992     value2 += value1;
 993     if (value2 < 0) value2 = 0;
 994     value1 = 0;
 995     }
 996
 997   /* Otherwise an unset length => characters before value1 */
 998
 999   else if (value2 < 0)
1000     {
1001     value2 = value1;
1002     value1 = 0;
1003     }
1004   }
1005
1006 /* For a non-negative offset, if the starting position is past the end of the
1007 string, the result will be the null string. Otherwise, an unset length means
1008 "rest"; just set it to the maximum - it will be cut down below if necessary. */
1009
1010 else
1011   {
1012   if (value1 > sublen)
1013     {
1014     value1 = sublen;
1015     value2 = 0;
1016     }
1017   else if (value2 < 0) value2 = sublen;
1018   }
1019
1020 /* Cut the length down to the maximum possible for the offset value, and get
1021 the required characters. */
1022
1023 if (value1 + value2 > sublen) value2 = sublen - value1;
1024 *len = value2;
1025 return subject + value1;
1026 }
1027
1028
1029
1030
1031 /*************************************************
1032 *            Old-style hash of a string          *
1033 *************************************************/
1034
1035 /* Perform the ${hash expansion operation.
1036
1037 Arguments:
1038   subject     the input string (an expanded substring)
1039   value1      the length of the output string; if greater or equal to the
1040                 length of the input string, the input string is returned
1041   value2      the number of hash characters to use, or 26 if negative
1042   len         set to the length of the returned string
1043
1044 Returns:      pointer to the output string, or NULL if there is an error
1045 */
1046
1047 static uschar *
1048 compute_hash(uschar *subject, int value1, int value2, int *len)
1049 {
1050 int sublen = Ustrlen(subject);
1051
1052 if (value2 < 0) value2 = 26;
1053 else if (value2 > Ustrlen(hashcodes))
1054   {
1055   expand_string_message =
1056     string_sprintf("hash count \"%d\" too big", value2);
1057   return NULL;
1058   }
1059
1060 /* Calculate the hash text. We know it is shorter than the original string, so
1061 can safely place it in subject[] (we know that subject is always itself an
1062 expanded substring). */
1063
1064 if (value1 < sublen)
1065   {
1066   int c;
1067   int i = 0;
1068   int j = value1;
1069   while ((c = (subject[j])) != 0)
1070     {
1071     int shift = (c + j++) & 7;
1072     subject[i] ^= (c << shift) | (c >> (8-shift));
1073     if (++i >= value1) i = 0;
1074     }
1075   for (i = 0; i < value1; i++)
1076     subject[i] = hashcodes[(subject[i]) % value2];
1077   }
1078 else value1 = sublen;
1079
1080 *len = value1;
1081 return subject;
1082 }
1083
1084
1085
1086
1087 /*************************************************
1088 *             Numeric hash of a string           *
1089 *************************************************/
1090
1091 /* Perform the ${nhash expansion operation. The first characters of the
1092 string are treated as most important, and get the highest prime numbers.
1093
1094 Arguments:
1095   subject     the input string
1096   value1      the maximum value of the first part of the result
1097   value2      the maximum value of the second part of the result,
1098                 or negative to produce only a one-part result
1099   len         set to the length of the returned string
1100
1101 Returns:  pointer to the output string, or NULL if there is an error.
1102 */
1103
1104 static uschar *
1105 compute_nhash (uschar *subject, int value1, int value2, int *len)
1106 {
1107 uschar *s = subject;
1108 int i = 0;
1109 unsigned long int total = 0; /* no overflow */
1110
1111 while (*s != 0)
1112   {
1113   if (i == 0) i = sizeof(prime)/sizeof(int) - 1;
1114   total += prime[i--] * (unsigned int)(*s++);
1115   }
1116
1117 /* If value2 is unset, just compute one number */
1118
1119 if (value2 < 0)
1120   {
1121   s = string_sprintf("%d", total % value1);
1122   }
1123
1124 /* Otherwise do a div/mod hash */
1125
1126 else
1127   {
1128   total = total % (value1 * value2);
1129   s = string_sprintf("%d/%d", total/value2, total % value2);
1130   }
1131
1132 *len = Ustrlen(s);
1133 return s;
1134 }
1135
1136
1137
1138
1139
1140 /*************************************************
1141 *     Find the value of a header or headers      *
1142 *************************************************/
1143
1144 /* Multiple instances of the same header get concatenated, and this function
1145 can also return a concatenation of all the header lines. When concatenating
1146 specific headers that contain lists of addresses, a comma is inserted between
1147 them. Otherwise we use a straight concatenation. Because some messages can have
1148 pathologically large number of lines, there is a limit on the length that is
1149 returned. Also, to avoid massive store use which would result from using
1150 string_cat() as it copies and extends strings, we do a preliminary pass to find
1151 out exactly how much store will be needed. On "normal" messages this will be
1152 pretty trivial.
1153
1154 Arguments:
1155   name          the name of the header, without the leading $header_ or $h_,
1156                 or NULL if a concatenation of all headers is required
1157   exists_only   TRUE if called from a def: test; don't need to build a string;
1158                 just return a string that is not "" and not "0" if the header
1159                 exists
1160   newsize       return the size of memory block that was obtained; may be NULL
1161                 if exists_only is TRUE
1162   want_raw      TRUE if called for $rh_ or $rheader_ variables; no processing,
1163                 other than concatenating, will be done on the header. Also used
1164                 for $message_headers_raw.
1165   charset       name of charset to translate MIME words to; used only if
1166                 want_raw is false; if NULL, no translation is done (this is
1167                 used for $bh_ and $bheader_)
1168
1169 Returns:        NULL if the header does not exist, else a pointer to a new
1170                 store block
1171 */
1172
1173 static uschar *
1174 find_header(uschar *name, BOOL exists_only, int *newsize, BOOL want_raw,
1175   uschar *charset)
1176 {
1177 BOOL found = name == NULL;
1178 int comma = 0;
1179 int len = found? 0 : Ustrlen(name);
1180 int i;
1181 uschar *yield = NULL;
1182 uschar *ptr = NULL;
1183
1184 /* Loop for two passes - saves code repetition */
1185
1186 for (i = 0; i < 2; i++)
1187   {
1188   int size = 0;
1189   header_line *h;
1190
1191   for (h = header_list; size < header_insert_maxlen && h != NULL; h = h->next)
1192     {
1193     if (h->type != htype_old && h->text != NULL)  /* NULL => Received: placeholder */
1194       {
1195       if (name == NULL || (len <= h->slen && strncmpic(name, h->text, len) == 0))
1196         {
1197         int ilen;
1198         uschar *t;
1199
1200         if (exists_only) return US"1";      /* don't need actual string */
1201         found = TRUE;
1202         t = h->text + len;                  /* text to insert */
1203         if (!want_raw)                      /* unless wanted raw, */
1204           while (isspace(*t)) t++;          /* remove leading white space */
1205         ilen = h->slen - (t - h->text);     /* length to insert */
1206
1207         /* Unless wanted raw, remove trailing whitespace, including the
1208         newline. */
1209
1210         if (!want_raw)
1211           while (ilen > 0 && isspace(t[ilen-1])) ilen--;
1212
1213         /* Set comma = 1 if handling a single header and it's one of those
1214         that contains an address list, except when asked for raw headers. Only
1215         need to do this once. */
1216
1217         if (!want_raw && name != NULL && comma == 0 &&
1218             Ustrchr("BCFRST", h->type) != NULL)
1219           comma = 1;
1220
1221         /* First pass - compute total store needed; second pass - compute
1222         total store used, including this header. */
1223
1224         size += ilen + comma + 1;  /* +1 for the newline */
1225
1226         /* Second pass - concatentate the data, up to a maximum. Note that
1227         the loop stops when size hits the limit. */
1228
1229         if (i != 0)
1230           {
1231           if (size > header_insert_maxlen)
1232             {
1233             ilen -= size - header_insert_maxlen - 1;
1234             comma = 0;
1235             }
1236           Ustrncpy(ptr, t, ilen);
1237           ptr += ilen;
1238
1239           /* For a non-raw header, put in the comma if needed, then add
1240           back the newline we removed above, provided there was some text in
1241           the header. */
1242
1243           if (!want_raw && ilen > 0)
1244             {
1245             if (comma != 0) *ptr++ = ',';
1246             *ptr++ = '\n';
1247             }
1248           }
1249         }
1250       }
1251     }
1252
1253   /* At end of first pass, return NULL if no header found. Then truncate size
1254   if necessary, and get the buffer to hold the data, returning the buffer size.
1255   */
1256
1257   if (i == 0)
1258     {
1259     if (!found) return NULL;
1260     if (size > header_insert_maxlen) size = header_insert_maxlen;
1261     *newsize = size + 1;
1262     ptr = yield = store_get(*newsize);
1263     }
1264   }
1265
1266 /* That's all we do for raw header expansion. */
1267
1268 if (want_raw)
1269   {
1270   *ptr = 0;
1271   }
1272
1273 /* Otherwise, remove a final newline and a redundant added comma. Then we do
1274 RFC 2047 decoding, translating the charset if requested. The rfc2047_decode2()
1275 function can return an error with decoded data if the charset translation
1276 fails. If decoding fails, it returns NULL. */
1277
1278 else
1279   {
1280   uschar *decoded, *error;
1281   if (ptr > yield && ptr[-1] == '\n') ptr--;
1282   if (ptr > yield && comma != 0 && ptr[-1] == ',') ptr--;
1283   *ptr = 0;
1284   decoded = rfc2047_decode2(yield, check_rfc2047_length, charset, '?', NULL,
1285     newsize, &error);
1286   if (error != NULL)
1287     {
1288     DEBUG(D_any) debug_printf("*** error in RFC 2047 decoding: %s\n"
1289       "    input was: %s\n", error, yield);
1290     }
1291   if (decoded != NULL) yield = decoded;
1292   }
1293
1294 return yield;
1295 }
1296
1297
1298
1299
1300 /*************************************************
1301 *               Find value of a variable         *
1302 *************************************************/
1303
1304 /* The table of variables is kept in alphabetic order, so we can search it
1305 using a binary chop. The "choplen" variable is nothing to do with the binary
1306 chop.
1307
1308 Arguments:
1309   name          the name of the variable being sought
1310   exists_only   TRUE if this is a def: test; passed on to find_header()
1311   skipping      TRUE => skip any processing evaluation; this is not the same as
1312                   exists_only because def: may test for values that are first
1313                   evaluated here
1314   newsize       pointer to an int which is initially zero; if the answer is in
1315                 a new memory buffer, *newsize is set to its size
1316
1317 Returns:        NULL if the variable does not exist, or
1318                 a pointer to the variable's contents, or
1319                 something non-NULL if exists_only is TRUE
1320 */
1321
1322 static uschar *
1323 find_variable(uschar *name, BOOL exists_only, BOOL skipping, int *newsize)
1324 {
1325 int first = 0;
1326 int last = var_table_size;
1327
1328 /* Handle ACL variables, whose names are of the form acl_cxxx or acl_mxxx.
1329 Originally, xxx had to be a number in the range 0-9 (later 0-19), but from
1330 release 4.64 onwards arbitrary names are permitted, as long as the first 5
1331 characters are acl_c or acl_m and the sixth is either a digit or an underscore
1332 (this gave backwards compatibility at the changeover). There may be built-in
1333 variables whose names start acl_ but they should never start in this way. This
1334 slightly messy specification is a consequence of the history, needless to say.
1335
1336 If an ACL variable does not exist, treat it as empty, unless strict_acl_vars is
1337 set, in which case give an error. */
1338
1339 if ((Ustrncmp(name, "acl_c", 5) == 0 || Ustrncmp(name, "acl_m", 5) == 0) &&
1340      !isalpha(name[5]))
1341   {
1342   tree_node *node =
1343     tree_search((name[4] == 'c')? acl_var_c : acl_var_m, name + 4);
1344   return (node == NULL)? (strict_acl_vars? NULL : US"") : node->data.ptr;
1345   }
1346
1347 /* Handle $auth<n> variables. */
1348
1349 if (Ustrncmp(name, "auth", 4) == 0)
1350   {
1351   uschar *endptr;
1352   int n = Ustrtoul(name + 4, &endptr, 10);
1353   if (*endptr == 0 && n != 0 && n <= AUTH_VARS)
1354     return (auth_vars[n-1] == NULL)? US"" : auth_vars[n-1];
1355   }
1356
1357 /* For all other variables, search the table */
1358
1359 while (last > first)
1360   {
1361   uschar *s, *domain;
1362   uschar **ss;
1363   int middle = (first + last)/2;
1364   int c = Ustrcmp(name, var_table[middle].name);
1365
1366   if (c > 0) { first = middle + 1; continue; }
1367   if (c < 0) { last = middle; continue; }
1368
1369   /* Found an existing variable. If in skipping state, the value isn't needed,
1370   and we want to avoid processing (such as looking up the host name). */
1371
1372   if (skipping) return US"";
1373
1374   switch (var_table[middle].type)
1375     {
1376 #ifdef EXPERIMENTAL_DOMAINKEYS
1377
1378     case vtype_dk_verify:
1379     if (dk_verify_block == NULL) return US"";
1380     s = NULL;
1381     if (Ustrcmp(var_table[middle].name, "dk_result") == 0)
1382       s = dk_verify_block->result_string;
1383     if (Ustrcmp(var_table[middle].name, "dk_sender") == 0)
1384       s = dk_verify_block->address;
1385     if (Ustrcmp(var_table[middle].name, "dk_sender_domain") == 0)
1386       s = dk_verify_block->domain;
1387     if (Ustrcmp(var_table[middle].name, "dk_sender_local_part") == 0)
1388       s = dk_verify_block->local_part;
1389
1390     if (Ustrcmp(var_table[middle].name, "dk_sender_source") == 0)
1391       switch(dk_verify_block->address_source) {
1392         case DK_EXIM_ADDRESS_NONE: s = US"0"; break;
1393         case DK_EXIM_ADDRESS_FROM_FROM: s = US"from"; break;
1394         case DK_EXIM_ADDRESS_FROM_SENDER: s = US"sender"; break;
1395       }
1396
1397     if (Ustrcmp(var_table[middle].name, "dk_status") == 0)
1398       switch(dk_verify_block->result) {
1399         case DK_EXIM_RESULT_ERR: s = US"error"; break;
1400         case DK_EXIM_RESULT_BAD_FORMAT: s = US"bad format"; break;
1401         case DK_EXIM_RESULT_NO_KEY: s = US"no key"; break;
1402         case DK_EXIM_RESULT_NO_SIGNATURE: s = US"no signature"; break;
1403         case DK_EXIM_RESULT_REVOKED: s = US"revoked"; break;
1404         case DK_EXIM_RESULT_NON_PARTICIPANT: s = US"non-participant"; break;
1405         case DK_EXIM_RESULT_GOOD: s = US"good"; break;
1406         case DK_EXIM_RESULT_BAD: s = US"bad"; break;
1407       }
1408
1409     if (Ustrcmp(var_table[middle].name, "dk_signsall") == 0)
1410       s = (dk_verify_block->signsall)? US"1" : US"0";
1411
1412     if (Ustrcmp(var_table[middle].name, "dk_testing") == 0)
1413       s = (dk_verify_block->testing)? US"1" : US"0";
1414
1415     if (Ustrcmp(var_table[middle].name, "dk_is_signed") == 0)
1416       s = (dk_verify_block->is_signed)? US"1" : US"0";
1417
1418     return (s == NULL)? US"" : s;
1419 #endif
1420
1421     case vtype_filter_int:
1422     if (!filter_running) return NULL;
1423     /* Fall through */
1424     /* VVVVVVVVVVVV */
1425     case vtype_int:
1426     sprintf(CS var_buffer, "%d", *(int *)(var_table[middle].value)); /* Integer */
1427     return var_buffer;
1428
1429     case vtype_ino:
1430     sprintf(CS var_buffer, "%ld", (long int)(*(ino_t *)(var_table[middle].value))); /* Inode */
1431     return var_buffer;
1432
1433     case vtype_gid:
1434     sprintf(CS var_buffer, "%ld", (long int)(*(gid_t *)(var_table[middle].value))); /* gid */
1435     return var_buffer;
1436
1437     case vtype_uid:
1438     sprintf(CS var_buffer, "%ld", (long int)(*(uid_t *)(var_table[middle].value))); /* uid */
1439     return var_buffer;
1440
1441     case vtype_stringptr:                      /* Pointer to string */
1442     s = *((uschar **)(var_table[middle].value));
1443     return (s == NULL)? US"" : s;
1444
1445     case vtype_pid:
1446     sprintf(CS var_buffer, "%d", (int)getpid()); /* pid */
1447     return var_buffer;
1448
1449     case vtype_load_avg:
1450     sprintf(CS var_buffer, "%d", OS_GETLOADAVG()); /* load_average */
1451     return var_buffer;
1452
1453     case vtype_host_lookup:                    /* Lookup if not done so */
1454     if (sender_host_name == NULL && sender_host_address != NULL &&
1455         !host_lookup_failed && host_name_lookup() == OK)
1456       host_build_sender_fullhost();
1457     return (sender_host_name == NULL)? US"" : sender_host_name;
1458
1459     case vtype_localpart:                      /* Get local part from address */
1460     s = *((uschar **)(var_table[middle].value));
1461     if (s == NULL) return US"";
1462     domain = Ustrrchr(s, '@');
1463     if (domain == NULL) return s;
1464     if (domain - s > sizeof(var_buffer) - 1)
1465       log_write(0, LOG_MAIN|LOG_PANIC_DIE, "local part longer than %d in "
1466         "string expansion", sizeof(var_buffer));
1467     Ustrncpy(var_buffer, s, domain - s);
1468     var_buffer[domain - s] = 0;
1469     return var_buffer;
1470
1471     case vtype_domain:                         /* Get domain from address */
1472     s = *((uschar **)(var_table[middle].value));
1473     if (s == NULL) return US"";
1474     domain = Ustrrchr(s, '@');
1475     return (domain == NULL)? US"" : domain + 1;
1476
1477     case vtype_msgheaders:
1478     return find_header(NULL, exists_only, newsize, FALSE, NULL);
1479
1480     case vtype_msgheaders_raw:
1481     return find_header(NULL, exists_only, newsize, TRUE, NULL);
1482
1483     case vtype_msgbody:                        /* Pointer to msgbody string */
1484     case vtype_msgbody_end:                    /* Ditto, the end of the msg */
1485     ss = (uschar **)(var_table[middle].value);
1486     if (*ss == NULL && deliver_datafile >= 0)  /* Read body when needed */
1487       {
1488       uschar *body;
1489       off_t start_offset = SPOOL_DATA_START_OFFSET;
1490       int len = message_body_visible;
1491       if (len > message_size) len = message_size;
1492       *ss = body = store_malloc(len+1);
1493       body[0] = 0;
1494       if (var_table[middle].type == vtype_msgbody_end)
1495         {
1496         struct stat statbuf;
1497         if (fstat(deliver_datafile, &statbuf) == 0)
1498           {
1499           start_offset = statbuf.st_size - len;
1500           if (start_offset < SPOOL_DATA_START_OFFSET)
1501             start_offset = SPOOL_DATA_START_OFFSET;
1502           }
1503         }
1504       lseek(deliver_datafile, start_offset, SEEK_SET);
1505       len = read(deliver_datafile, body, len);
1506       if (len > 0)
1507         {
1508         body[len] = 0;
1509         while (len > 0)
1510           {
1511           if (body[--len] == '\n' || body[len] == 0) body[len] = ' ';
1512           }
1513         }
1514       }
1515     return (*ss == NULL)? US"" : *ss;
1516
1517     case vtype_todbsdin:                       /* BSD inbox time of day */
1518     return tod_stamp(tod_bsdin);
1519
1520     case vtype_tode:                           /* Unix epoch time of day */
1521     return tod_stamp(tod_epoch);
1522
1523     case vtype_todf:                           /* Full time of day */
1524     return tod_stamp(tod_full);
1525
1526     case vtype_todl:                           /* Log format time of day */
1527     return tod_stamp(tod_log_bare);            /* (without timezone) */
1528
1529     case vtype_todzone:                        /* Time zone offset only */
1530     return tod_stamp(tod_zone);
1531
1532     case vtype_todzulu:                        /* Zulu time */
1533     return tod_stamp(tod_zulu);
1534
1535     case vtype_todlf:                          /* Log file datestamp tod */
1536     return tod_stamp(tod_log_datestamp);
1537
1538     case vtype_reply:                          /* Get reply address */
1539     s = find_header(US"reply-to:", exists_only, newsize, TRUE,
1540       headers_charset);
1541     if (s != NULL) while (isspace(*s)) s++;
1542     if (s == NULL || *s == 0)
1543       {
1544       *newsize = 0;                            /* For the *s==0 case */
1545       s = find_header(US"from:", exists_only, newsize, TRUE, headers_charset);
1546       }
1547     if (s != NULL)
1548       {
1549       uschar *t;
1550       while (isspace(*s)) s++;
1551       for (t = s; *t != 0; t++) if (*t == '\n') *t = ' ';
1552       while (t > s && isspace(t[-1])) t--;
1553       *t = 0;
1554       }
1555     return (s == NULL)? US"" : s;
1556
1557     /* A recipients list is available only during system message filtering,
1558     during ACL processing after DATA, and while expanding pipe commands
1559     generated from a system filter, but not elsewhere. */
1560
1561     case vtype_recipients:
1562     if (!enable_dollar_recipients) return NULL; else
1563       {
1564       int size = 128;
1565       int ptr = 0;
1566       int i;
1567       s = store_get(size);
1568       for (i = 0; i < recipients_count; i++)
1569         {
1570         if (i != 0) s = string_cat(s, &size, &ptr, US", ", 2);
1571         s = string_cat(s, &size, &ptr, recipients_list[i].address,
1572           Ustrlen(recipients_list[i].address));
1573         }
1574       s[ptr] = 0;     /* string_cat() leaves room */
1575       }
1576     return s;
1577
1578     case vtype_pspace:
1579       {
1580       int inodes;
1581       sprintf(CS var_buffer, "%d",
1582         receive_statvfs(var_table[middle].value == (void *)TRUE, &inodes));
1583       }
1584     return var_buffer;
1585
1586     case vtype_pinodes:
1587       {
1588       int inodes;
1589       (void) receive_statvfs(var_table[middle].value == (void *)TRUE, &inodes);
1590       sprintf(CS var_buffer, "%d", inodes);
1591       }
1592     return var_buffer;
1593     }
1594   }
1595
1596 return NULL;          /* Unknown variable name */
1597 }
1598
1599
1600
1601
1602 /*************************************************
1603 *           Read and expand substrings           *
1604 *************************************************/
1605
1606 /* This function is called to read and expand argument substrings for various
1607 expansion items. Some have a minimum requirement that is less than the maximum;
1608 in these cases, the first non-present one is set to NULL.
1609
1610 Arguments:
1611   sub        points to vector of pointers to set
1612   n          maximum number of substrings
1613   m          minimum required
1614   sptr       points to current string pointer
1615   skipping   the skipping flag
1616   check_end  if TRUE, check for final '}'
1617   name       name of item, for error message
1618
1619 Returns:     0 OK; string pointer updated
1620              1 curly bracketing error (too few arguments)
1621              2 too many arguments (only if check_end is set); message set
1622              3 other error (expansion failure)
1623 */
1624
1625 static int
1626 read_subs(uschar **sub, int n, int m, uschar **sptr, BOOL skipping,
1627   BOOL check_end, uschar *name)
1628 {
1629 int i;
1630 uschar *s = *sptr;
1631
1632 while (isspace(*s)) s++;
1633 for (i = 0; i < n; i++)
1634   {
1635   if (*s != '{')
1636     {
1637     if (i < m) return 1;
1638     sub[i] = NULL;
1639     break;
1640     }
1641   sub[i] = expand_string_internal(s+1, TRUE, &s, skipping);
1642   if (sub[i] == NULL) return 3;
1643   if (*s++ != '}') return 1;
1644   while (isspace(*s)) s++;
1645   }
1646 if (check_end && *s++ != '}')
1647   {
1648   if (s[-1] == '{')
1649     {
1650     expand_string_message = string_sprintf("Too many arguments for \"%s\" "
1651       "(max is %d)", name, n);
1652     return 2;
1653     }
1654   return 1;
1655   }
1656
1657 *sptr = s;
1658 return 0;
1659 }
1660
1661
1662
1663
1664 /*************************************************
1665 *     Elaborate message for bad variable         *
1666 *************************************************/
1667
1668 /* For the "unknown variable" message, take a look at the variable's name, and
1669 give additional information about possible ACL variables. The extra information
1670 is added on to expand_string_message.
1671
1672 Argument:   the name of the variable
1673 Returns:    nothing
1674 */
1675
1676 static void
1677 check_variable_error_message(uschar *name)
1678 {
1679 if (Ustrncmp(name, "acl_", 4) == 0)
1680   expand_string_message = string_sprintf("%s (%s)", expand_string_message,
1681     (name[4] == 'c' || name[4] == 'm')?
1682       (isalpha(name[5])?
1683         US"6th character of a user-defined ACL variable must be a digit or underscore" :
1684         US"strict_acl_vars is set"    /* Syntax is OK, it has to be this */
1685       ) :
1686       US"user-defined ACL variables must start acl_c or acl_m");
1687 }
1688
1689
1690
1691 /*************************************************
1692 *        Read and evaluate a condition           *
1693 *************************************************/
1694
1695 /*
1696 Arguments:
1697   s        points to the start of the condition text
1698   yield    points to a BOOL to hold the result of the condition test;
1699            if NULL, we are just reading through a condition that is
1700            part of an "or" combination to check syntax, or in a state
1701            where the answer isn't required
1702
1703 Returns:   a pointer to the first character after the condition, or
1704            NULL after an error
1705 */
1706
1707 static uschar *
1708 eval_condition(uschar *s, BOOL *yield)
1709 {
1710 BOOL testfor = TRUE;
1711 BOOL tempcond, combined_cond;
1712 BOOL *subcondptr;
1713 int i, rc, cond_type, roffset;
1714 int num[2];
1715 struct stat statbuf;
1716 uschar name[256];
1717 uschar *sub[4];
1718
1719 const pcre *re;
1720 const uschar *rerror;
1721
1722 for (;;)
1723   {
1724   while (isspace(*s)) s++;
1725   if (*s == '!') { testfor = !testfor; s++; } else break;
1726   }
1727
1728 /* Numeric comparisons are symbolic */
1729
1730 if (*s == '=' || *s == '>' || *s == '<')
1731   {
1732   int p = 0;
1733   name[p++] = *s++;
1734   if (*s == '=')
1735     {
1736     name[p++] = '=';
1737     s++;
1738     }
1739   name[p] = 0;
1740   }
1741
1742 /* All other conditions are named */
1743
1744 else s = read_name(name, 256, s, US"_");
1745
1746 /* If we haven't read a name, it means some non-alpha character is first. */
1747
1748 if (name[0] == 0)
1749   {
1750   expand_string_message = string_sprintf("condition name expected, "
1751     "but found \"%.16s\"", s);
1752   return NULL;
1753   }
1754
1755 /* Find which condition we are dealing with, and switch on it */
1756
1757 cond_type = chop_match(name, cond_table, sizeof(cond_table)/sizeof(uschar *));
1758 switch(cond_type)
1759   {
1760   /* def: tests for a non-empty variable, or for the existence of a header. If
1761   yield == NULL we are in a skipping state, and don't care about the answer. */
1762
1763   case ECOND_DEF:
1764   if (*s != ':')
1765     {
1766     expand_string_message = US"\":\" expected after \"def\"";
1767     return NULL;
1768     }
1769
1770   s = read_name(name, 256, s+1, US"_");
1771
1772   /* Test for a header's existence. If the name contains a closing brace
1773   character, this may be a user error where the terminating colon has been
1774   omitted. Set a flag to adjust a subsequent error message in this case. */
1775
1776   if (Ustrncmp(name, "h_", 2) == 0 ||
1777       Ustrncmp(name, "rh_", 3) == 0 ||
1778       Ustrncmp(name, "bh_", 3) == 0 ||
1779       Ustrncmp(name, "header_", 7) == 0 ||
1780       Ustrncmp(name, "rheader_", 8) == 0 ||
1781       Ustrncmp(name, "bheader_", 8) == 0)
1782     {
1783     s = read_header_name(name, 256, s);
1784     if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
1785     if (yield != NULL) *yield =
1786       (find_header(name, TRUE, NULL, FALSE, NULL) != NULL) == testfor;
1787     }
1788
1789   /* Test for a variable's having a non-empty value. A non-existent variable
1790   causes an expansion failure. */
1791
1792   else
1793     {
1794     uschar *value = find_variable(name, TRUE, yield == NULL, NULL);
1795     if (value == NULL)
1796       {
1797       expand_string_message = (name[0] == 0)?
1798         string_sprintf("variable name omitted after \"def:\"") :
1799         string_sprintf("unknown variable \"%s\" after \"def:\"", name);
1800       check_variable_error_message(name);
1801       return NULL;
1802       }
1803     if (yield != NULL) *yield = (value[0] != 0) == testfor;
1804     }
1805
1806   return s;
1807
1808
1809   /* first_delivery tests for first delivery attempt */
1810
1811   case ECOND_FIRST_DELIVERY:
1812   if (yield != NULL) *yield = deliver_firsttime == testfor;
1813   return s;
1814
1815
1816   /* queue_running tests for any process started by a queue runner */
1817
1818   case ECOND_QUEUE_RUNNING:
1819   if (yield != NULL) *yield = (queue_run_pid != (pid_t)0) == testfor;
1820   return s;
1821
1822
1823   /* exists:  tests for file existence
1824        isip:  tests for any IP address
1825       isip4:  tests for an IPv4 address
1826       isip6:  tests for an IPv6 address
1827         pam:  does PAM authentication
1828      radius:  does RADIUS authentication
1829    ldapauth:  does LDAP authentication
1830     pwcheck:  does Cyrus SASL pwcheck authentication
1831   */
1832
1833   case ECOND_EXISTS:
1834   case ECOND_ISIP:
1835   case ECOND_ISIP4:
1836   case ECOND_ISIP6:
1837   case ECOND_PAM:
1838   case ECOND_RADIUS:
1839   case ECOND_LDAPAUTH:
1840   case ECOND_PWCHECK:
1841
1842   while (isspace(*s)) s++;
1843   if (*s != '{') goto COND_FAILED_CURLY_START;
1844
1845   sub[0] = expand_string_internal(s+1, TRUE, &s, yield == NULL);
1846   if (sub[0] == NULL) return NULL;
1847   if (*s++ != '}') goto COND_FAILED_CURLY_END;
1848
1849   if (yield == NULL) return s;   /* No need to run the test if skipping */
1850
1851   switch(cond_type)
1852     {
1853     case ECOND_EXISTS:
1854     if ((expand_forbid & RDO_EXISTS) != 0)
1855       {
1856       expand_string_message = US"File existence tests are not permitted";
1857       return NULL;
1858       }
1859     *yield = (Ustat(sub[0], &statbuf) == 0) == testfor;
1860     break;
1861
1862     case ECOND_ISIP:
1863     case ECOND_ISIP4:
1864     case ECOND_ISIP6:
1865     rc = string_is_ip_address(sub[0], NULL);
1866     *yield = ((cond_type == ECOND_ISIP)? (rc != 0) :
1867              (cond_type == ECOND_ISIP4)? (rc == 4) : (rc == 6)) == testfor;
1868     break;
1869
1870     /* Various authentication tests - all optionally compiled */
1871
1872     case ECOND_PAM:
1873     #ifdef SUPPORT_PAM
1874     rc = auth_call_pam(sub[0], &expand_string_message);
1875     goto END_AUTH;
1876     #else
1877     goto COND_FAILED_NOT_COMPILED;
1878     #endif  /* SUPPORT_PAM */
1879
1880     case ECOND_RADIUS:
1881     #ifdef RADIUS_CONFIG_FILE
1882     rc = auth_call_radius(sub[0], &expand_string_message);
1883     goto END_AUTH;
1884     #else
1885     goto COND_FAILED_NOT_COMPILED;
1886     #endif  /* RADIUS_CONFIG_FILE */
1887
1888     case ECOND_LDAPAUTH:
1889     #ifdef LOOKUP_LDAP
1890       {
1891       /* Just to keep the interface the same */
1892       BOOL do_cache;
1893       int old_pool = store_pool;
1894       store_pool = POOL_SEARCH;
1895       rc = eldapauth_find((void *)(-1), NULL, sub[0], Ustrlen(sub[0]), NULL,
1896         &expand_string_message, &do_cache);
1897       store_pool = old_pool;
1898       }
1899     goto END_AUTH;
1900     #else
1901     goto COND_FAILED_NOT_COMPILED;
1902     #endif  /* LOOKUP_LDAP */
1903
1904     case ECOND_PWCHECK:
1905     #ifdef CYRUS_PWCHECK_SOCKET
1906     rc = auth_call_pwcheck(sub[0], &expand_string_message);
1907     goto END_AUTH;
1908     #else
1909     goto COND_FAILED_NOT_COMPILED;
1910     #endif  /* CYRUS_PWCHECK_SOCKET */
1911
1912     #if defined(SUPPORT_PAM) || defined(RADIUS_CONFIG_FILE) || \
1913         defined(LOOKUP_LDAP) || defined(CYRUS_PWCHECK_SOCKET)
1914     END_AUTH:
1915     if (rc == ERROR || rc == DEFER) return NULL;
1916     *yield = (rc == OK) == testfor;
1917     #endif
1918     }
1919   return s;
1920
1921
1922   /* saslauthd: does Cyrus saslauthd authentication. Four parameters are used:
1923
1924      ${if saslauthd {{username}{password}{service}{realm}}  {yes}[no}}
1925
1926   However, the last two are optional. That is why the whole set is enclosed
1927   in their own set or braces. */
1928
1929   case ECOND_SASLAUTHD:
1930   #ifndef CYRUS_SASLAUTHD_SOCKET
1931   goto COND_FAILED_NOT_COMPILED;
1932   #else
1933   while (isspace(*s)) s++;
1934   if (*s++ != '{') goto COND_FAILED_CURLY_START;
1935   switch(read_subs(sub, 4, 2, &s, yield == NULL, TRUE, US"saslauthd"))
1936     {
1937     case 1: expand_string_message = US"too few arguments or bracketing "
1938       "error for saslauthd";
1939     case 2:
1940     case 3: return NULL;
1941     }
1942   if (sub[2] == NULL) sub[3] = NULL;  /* realm if no service */
1943   if (yield != NULL)
1944     {
1945     int rc;
1946     rc = auth_call_saslauthd(sub[0], sub[1], sub[2], sub[3],
1947       &expand_string_message);
1948     if (rc == ERROR || rc == DEFER) return NULL;
1949     *yield = (rc == OK) == testfor;
1950     }
1951   return s;
1952   #endif /* CYRUS_SASLAUTHD_SOCKET */
1953
1954
1955   /* symbolic operators for numeric and string comparison, and a number of
1956   other operators, all requiring two arguments.
1957
1958   match:             does a regular expression match and sets up the numerical
1959                        variables if it succeeds
1960   match_address:     matches in an address list
1961   match_domain:      matches in a domain list
1962   match_ip:          matches a host list that is restricted to IP addresses
1963   match_local_part:  matches in a local part list
1964   crypteq:           encrypts plaintext and compares against an encrypted text,
1965                        using crypt(), crypt16(), MD5 or SHA-1
1966   */
1967
1968   case ECOND_MATCH:
1969   case ECOND_MATCH_ADDRESS:
1970   case ECOND_MATCH_DOMAIN:
1971   case ECOND_MATCH_IP:
1972   case ECOND_MATCH_LOCAL_PART:
1973   case ECOND_CRYPTEQ:
1974
1975   case ECOND_NUM_L:     /* Numerical comparisons */
1976   case ECOND_NUM_LE:
1977   case ECOND_NUM_E:
1978   case ECOND_NUM_EE:
1979   case ECOND_NUM_G:
1980   case ECOND_NUM_GE:
1981
1982   case ECOND_STR_LT:    /* String comparisons */
1983   case ECOND_STR_LTI:
1984   case ECOND_STR_LE:
1985   case ECOND_STR_LEI:
1986   case ECOND_STR_EQ:
1987   case ECOND_STR_EQI:
1988   case ECOND_STR_GT:
1989   case ECOND_STR_GTI:
1990   case ECOND_STR_GE:
1991   case ECOND_STR_GEI:
1992
1993   for (i = 0; i < 2; i++)
1994     {
1995     while (isspace(*s)) s++;
1996     if (*s != '{')
1997       {
1998       if (i == 0) goto COND_FAILED_CURLY_START;
1999       expand_string_message = string_sprintf("missing 2nd string in {} "
2000         "after \"%s\"", name);
2001       return NULL;
2002       }
2003     sub[i] = expand_string_internal(s+1, TRUE, &s, yield == NULL);
2004     if (sub[i] == NULL) return NULL;
2005     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2006
2007     /* Convert to numerical if required; we know that the names of all the
2008     conditions that compare numbers do not start with a letter. This just saves
2009     checking for them individually. */
2010
2011     if (!isalpha(name[0]) && yield != NULL)
2012       {
2013       if (sub[i][0] == 0)
2014         {
2015         num[i] = 0;
2016         DEBUG(D_expand)
2017           debug_printf("empty string cast to zero for numerical comparison\n");
2018         }
2019       else
2020         {
2021         num[i] = expand_string_integer(sub[i], FALSE);
2022         if (expand_string_message != NULL) return NULL;
2023         }
2024       }
2025     }
2026
2027   /* Result not required */
2028
2029   if (yield == NULL) return s;
2030
2031   /* Do an appropriate comparison */
2032
2033   switch(cond_type)
2034     {
2035     case ECOND_NUM_E:
2036     case ECOND_NUM_EE:
2037     *yield = (num[0] == num[1]) == testfor;
2038     break;
2039
2040     case ECOND_NUM_G:
2041     *yield = (num[0] > num[1]) == testfor;
2042     break;
2043
2044     case ECOND_NUM_GE:
2045     *yield = (num[0] >= num[1]) == testfor;
2046     break;
2047
2048     case ECOND_NUM_L:
2049     *yield = (num[0] < num[1]) == testfor;
2050     break;
2051
2052     case ECOND_NUM_LE:
2053     *yield = (num[0] <= num[1]) == testfor;
2054     break;
2055
2056     case ECOND_STR_LT:
2057     *yield = (Ustrcmp(sub[0], sub[1]) < 0) == testfor;
2058     break;
2059
2060     case ECOND_STR_LTI:
2061     *yield = (strcmpic(sub[0], sub[1]) < 0) == testfor;
2062     break;
2063
2064     case ECOND_STR_LE:
2065     *yield = (Ustrcmp(sub[0], sub[1]) <= 0) == testfor;
2066     break;
2067
2068     case ECOND_STR_LEI:
2069     *yield = (strcmpic(sub[0], sub[1]) <= 0) == testfor;
2070     break;
2071
2072     case ECOND_STR_EQ:
2073     *yield = (Ustrcmp(sub[0], sub[1]) == 0) == testfor;
2074     break;
2075
2076     case ECOND_STR_EQI:
2077     *yield = (strcmpic(sub[0], sub[1]) == 0) == testfor;
2078     break;
2079
2080     case ECOND_STR_GT:
2081     *yield = (Ustrcmp(sub[0], sub[1]) > 0) == testfor;
2082     break;
2083
2084     case ECOND_STR_GTI:
2085     *yield = (strcmpic(sub[0], sub[1]) > 0) == testfor;
2086     break;
2087
2088     case ECOND_STR_GE:
2089     *yield = (Ustrcmp(sub[0], sub[1]) >= 0) == testfor;
2090     break;
2091
2092     case ECOND_STR_GEI:
2093     *yield = (strcmpic(sub[0], sub[1]) >= 0) == testfor;
2094     break;
2095
2096     case ECOND_MATCH:   /* Regular expression match */
2097     re = pcre_compile(CS sub[1], PCRE_COPT, (const char **)&rerror, &roffset,
2098       NULL);
2099     if (re == NULL)
2100       {
2101       expand_string_message = string_sprintf("regular expression error in "
2102         "\"%s\": %s at offset %d", sub[1], rerror, roffset);
2103       return NULL;
2104       }
2105     *yield = regex_match_and_setup(re, sub[0], 0, -1) == testfor;
2106     break;
2107
2108     case ECOND_MATCH_ADDRESS:  /* Match in an address list */
2109     rc = match_address_list(sub[0], TRUE, FALSE, &(sub[1]), NULL, -1, 0, NULL);
2110     goto MATCHED_SOMETHING;
2111
2112     case ECOND_MATCH_DOMAIN:   /* Match in a domain list */
2113     rc = match_isinlist(sub[0], &(sub[1]), 0, &domainlist_anchor, NULL,
2114       MCL_DOMAIN + MCL_NOEXPAND, TRUE, NULL);
2115     goto MATCHED_SOMETHING;
2116
2117     case ECOND_MATCH_IP:       /* Match IP address in a host list */
2118     if (sub[0][0] != 0 && string_is_ip_address(sub[0], NULL) == 0)
2119       {
2120       expand_string_message = string_sprintf("\"%s\" is not an IP address",
2121         sub[0]);
2122       return NULL;
2123       }
2124     else
2125       {
2126       unsigned int *nullcache = NULL;
2127       check_host_block cb;
2128
2129       cb.host_name = US"";
2130       cb.host_address = sub[0];
2131
2132       /* If the host address starts off ::ffff: it is an IPv6 address in
2133       IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2134       addresses. */
2135
2136       cb.host_ipv4 = (Ustrncmp(cb.host_address, "::ffff:", 7) == 0)?
2137         cb.host_address + 7 : cb.host_address;
2138
2139       rc = match_check_list(
2140              &sub[1],                   /* the list */
2141              0,                         /* separator character */
2142              &hostlist_anchor,          /* anchor pointer */
2143              &nullcache,                /* cache pointer */
2144              check_host,                /* function for testing */
2145              &cb,                       /* argument for function */
2146              MCL_HOST,                  /* type of check */
2147              sub[0],                    /* text for debugging */
2148              NULL);                     /* where to pass back data */
2149       }
2150     goto MATCHED_SOMETHING;
2151
2152     case ECOND_MATCH_LOCAL_PART:
2153     rc = match_isinlist(sub[0], &(sub[1]), 0, &localpartlist_anchor, NULL,
2154       MCL_LOCALPART + MCL_NOEXPAND, TRUE, NULL);
2155     /* Fall through */
2156     /* VVVVVVVVVVVV */
2157     MATCHED_SOMETHING:
2158     switch(rc)
2159       {
2160       case OK:
2161       *yield = testfor;
2162       break;
2163
2164       case FAIL:
2165       *yield = !testfor;
2166       break;
2167
2168       case DEFER:
2169       expand_string_message = string_sprintf("unable to complete match "
2170         "against \"%s\": %s", sub[1], search_error_message);
2171       return NULL;
2172       }
2173
2174     break;
2175
2176     /* Various "encrypted" comparisons. If the second string starts with
2177     "{" then an encryption type is given. Default to crypt() or crypt16()
2178     (build-time choice). */
2179
2180     case ECOND_CRYPTEQ:
2181     #ifndef SUPPORT_CRYPTEQ
2182     goto COND_FAILED_NOT_COMPILED;
2183     #else
2184     if (strncmpic(sub[1], US"{md5}", 5) == 0)
2185       {
2186       int sublen = Ustrlen(sub[1]+5);
2187       md5 base;
2188       uschar digest[16];
2189
2190       md5_start(&base);
2191       md5_end(&base, (uschar *)sub[0], Ustrlen(sub[0]), digest);
2192
2193       /* If the length that we are comparing against is 24, the MD5 digest
2194       is expressed as a base64 string. This is the way LDAP does it. However,
2195       some other software uses a straightforward hex representation. We assume
2196       this if the length is 32. Other lengths fail. */
2197
2198       if (sublen == 24)
2199         {
2200         uschar *coded = auth_b64encode((uschar *)digest, 16);
2201         DEBUG(D_auth) debug_printf("crypteq: using MD5+B64 hashing\n"
2202           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2203         *yield = (Ustrcmp(coded, sub[1]+5) == 0) == testfor;
2204         }
2205       else if (sublen == 32)
2206         {
2207         int i;
2208         uschar coded[36];
2209         for (i = 0; i < 16; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2210         coded[32] = 0;
2211         DEBUG(D_auth) debug_printf("crypteq: using MD5+hex hashing\n"
2212           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2213         *yield = (strcmpic(coded, sub[1]+5) == 0) == testfor;
2214         }
2215       else
2216         {
2217         DEBUG(D_auth) debug_printf("crypteq: length for MD5 not 24 or 32: "
2218           "fail\n  crypted=%s\n", sub[1]+5);
2219         *yield = !testfor;
2220         }
2221       }
2222
2223     else if (strncmpic(sub[1], US"{sha1}", 6) == 0)
2224       {
2225       int sublen = Ustrlen(sub[1]+6);
2226       sha1 base;
2227       uschar digest[20];
2228
2229       sha1_start(&base);
2230       sha1_end(&base, (uschar *)sub[0], Ustrlen(sub[0]), digest);
2231
2232       /* If the length that we are comparing against is 28, assume the SHA1
2233       digest is expressed as a base64 string. If the length is 40, assume a
2234       straightforward hex representation. Other lengths fail. */
2235
2236       if (sublen == 28)
2237         {
2238         uschar *coded = auth_b64encode((uschar *)digest, 20);
2239         DEBUG(D_auth) debug_printf("crypteq: using SHA1+B64 hashing\n"
2240           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2241         *yield = (Ustrcmp(coded, sub[1]+6) == 0) == testfor;
2242         }
2243       else if (sublen == 40)
2244         {
2245         int i;
2246         uschar coded[44];
2247         for (i = 0; i < 20; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2248         coded[40] = 0;
2249         DEBUG(D_auth) debug_printf("crypteq: using SHA1+hex hashing\n"
2250           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2251         *yield = (strcmpic(coded, sub[1]+6) == 0) == testfor;
2252         }
2253       else
2254         {
2255         DEBUG(D_auth) debug_printf("crypteq: length for SHA-1 not 28 or 40: "
2256           "fail\n  crypted=%s\n", sub[1]+6);
2257         *yield = !testfor;
2258         }
2259       }
2260
2261     else   /* {crypt} or {crypt16} and non-{ at start */
2262       {
2263       int which = 0;
2264       uschar *coded;
2265
2266       if (strncmpic(sub[1], US"{crypt}", 7) == 0)
2267         {
2268         sub[1] += 7;
2269         which = 1;
2270         }
2271       else if (strncmpic(sub[1], US"{crypt16}", 9) == 0)
2272         {
2273         sub[1] += 9;
2274         which = 2;
2275         }
2276       else if (sub[1][0] == '{')
2277         {
2278         expand_string_message = string_sprintf("unknown encryption mechanism "
2279           "in \"%s\"", sub[1]);
2280         return NULL;
2281         }
2282
2283       switch(which)
2284         {
2285         case 0:  coded = US DEFAULT_CRYPT(CS sub[0], CS sub[1]); break;
2286         case 1:  coded = US crypt(CS sub[0], CS sub[1]); break;
2287         default: coded = US crypt16(CS sub[0], CS sub[1]); break;
2288         }
2289
2290       #define STR(s) # s
2291       #define XSTR(s) STR(s)
2292       DEBUG(D_auth) debug_printf("crypteq: using %s()\n"
2293         "  subject=%s\n  crypted=%s\n",
2294         (which == 0)? XSTR(DEFAULT_CRYPT) : (which == 1)? "crypt" : "crypt16",
2295         coded, sub[1]);
2296       #undef STR
2297       #undef XSTR
2298
2299       /* If the encrypted string contains fewer than two characters (for the
2300       salt), force failure. Otherwise we get false positives: with an empty
2301       string the yield of crypt() is an empty string! */
2302
2303       *yield = (Ustrlen(sub[1]) < 2)? !testfor :
2304         (Ustrcmp(coded, sub[1]) == 0) == testfor;
2305       }
2306     break;
2307     #endif  /* SUPPORT_CRYPTEQ */
2308     }   /* Switch for comparison conditions */
2309
2310   return s;    /* End of comparison conditions */
2311
2312
2313   /* and/or: computes logical and/or of several conditions */
2314
2315   case ECOND_AND:
2316   case ECOND_OR:
2317   subcondptr = (yield == NULL)? NULL : &tempcond;
2318   combined_cond = (cond_type == ECOND_AND);
2319
2320   while (isspace(*s)) s++;
2321   if (*s++ != '{') goto COND_FAILED_CURLY_START;
2322
2323   for (;;)
2324     {
2325     while (isspace(*s)) s++;
2326     if (*s == '}') break;
2327     if (*s != '{')
2328       {
2329       expand_string_message = string_sprintf("each subcondition "
2330         "inside an \"%s{...}\" condition must be in its own {}", name);
2331       return NULL;
2332       }
2333
2334     s = eval_condition(s+1, subcondptr);
2335     if (s == NULL)
2336       {
2337       expand_string_message = string_sprintf("%s inside \"%s{...}\" condition",
2338         expand_string_message, name);
2339       return NULL;
2340       }
2341     while (isspace(*s)) s++;
2342
2343     if (*s++ != '}')
2344       {
2345       expand_string_message = string_sprintf("missing } at end of condition "
2346         "inside \"%s\" group", name);
2347       return NULL;
2348       }
2349
2350     if (yield != NULL)
2351       {
2352       if (cond_type == ECOND_AND)
2353         {
2354         combined_cond &= tempcond;
2355         if (!combined_cond) subcondptr = NULL;  /* once false, don't */
2356         }                                       /* evaluate any more */
2357       else
2358         {
2359         combined_cond |= tempcond;
2360         if (combined_cond) subcondptr = NULL;   /* once true, don't */
2361         }                                       /* evaluate any more */
2362       }
2363     }
2364
2365   if (yield != NULL) *yield = (combined_cond == testfor);
2366   return ++s;
2367
2368
2369   /* forall/forany: iterates a condition with different values */
2370
2371   case ECOND_FORALL:
2372   case ECOND_FORANY:
2373     {
2374     int sep = 0;
2375     uschar *save_iterate_item = iterate_item;
2376
2377     while (isspace(*s)) s++;
2378     if (*s++ != '{') goto COND_FAILED_CURLY_START;
2379     sub[0] = expand_string_internal(s, TRUE, &s, (yield == NULL));
2380     if (sub[0] == NULL) return NULL;
2381     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2382
2383     while (isspace(*s)) s++;
2384     if (*s++ != '{') goto COND_FAILED_CURLY_START;
2385
2386     sub[1] = s;
2387
2388     /* Call eval_condition once, with result discarded (as if scanning a
2389     "false" part). This allows us to find the end of the condition, because if
2390     the list it empty, we won't actually evaluate the condition for real. */
2391
2392     s = eval_condition(sub[1], NULL);
2393     if (s == NULL)
2394       {
2395       expand_string_message = string_sprintf("%s inside \"%s\" condition",
2396         expand_string_message, name);
2397       return NULL;
2398       }
2399     while (isspace(*s)) s++;
2400
2401     if (*s++ != '}')
2402       {
2403       expand_string_message = string_sprintf("missing } at end of condition "
2404         "inside \"%s\"", name);
2405       return NULL;
2406       }
2407
2408     if (yield != NULL) *yield = !testfor;
2409     while ((iterate_item = string_nextinlist(&sub[0], &sep, NULL, 0)) != NULL)
2410       {
2411       DEBUG(D_expand) debug_printf("%s: $item = \"%s\"\n", name, iterate_item);
2412       if (eval_condition(sub[1], &tempcond) == NULL)
2413         {
2414         expand_string_message = string_sprintf("%s inside \"%s\" condition",
2415           expand_string_message, name);
2416         iterate_item = save_iterate_item;
2417         return NULL;
2418         }
2419       DEBUG(D_expand) debug_printf("%s: condition evaluated to %s\n", name,
2420         tempcond? "true":"false");
2421
2422       if (yield != NULL) *yield = (tempcond == testfor);
2423       if (tempcond == (cond_type == ECOND_FORANY)) break;
2424       }
2425
2426     iterate_item = save_iterate_item;
2427     return s;
2428     }
2429
2430
2431   /* Unknown condition */
2432
2433   default:
2434   expand_string_message = string_sprintf("unknown condition \"%s\"", name);
2435   return NULL;
2436   }   /* End switch on condition type */
2437
2438 /* Missing braces at start and end of data */
2439
2440 COND_FAILED_CURLY_START:
2441 expand_string_message = string_sprintf("missing { after \"%s\"", name);
2442 return NULL;
2443
2444 COND_FAILED_CURLY_END:
2445 expand_string_message = string_sprintf("missing } at end of \"%s\" condition",
2446   name);
2447 return NULL;
2448
2449 /* A condition requires code that is not compiled */
2450
2451 #if !defined(SUPPORT_PAM) || !defined(RADIUS_CONFIG_FILE) || \
2452     !defined(LOOKUP_LDAP) || !defined(CYRUS_PWCHECK_SOCKET) || \
2453     !defined(SUPPORT_CRYPTEQ) || !defined(CYRUS_SASLAUTHD_SOCKET)
2454 COND_FAILED_NOT_COMPILED:
2455 expand_string_message = string_sprintf("support for \"%s\" not compiled",
2456   name);
2457 return NULL;
2458 #endif
2459 }
2460
2461
2462
2463
2464 /*************************************************
2465 *          Save numerical variables              *
2466 *************************************************/
2467
2468 /* This function is called from items such as "if" that want to preserve and
2469 restore the numbered variables.
2470
2471 Arguments:
2472   save_expand_string    points to an array of pointers to set
2473   save_expand_nlength   points to an array of ints for the lengths
2474
2475 Returns:                the value of expand max to save
2476 */
2477
2478 static int
2479 save_expand_strings(uschar **save_expand_nstring, int *save_expand_nlength)
2480 {
2481 int i;
2482 for (i = 0; i <= expand_nmax; i++)
2483   {
2484   save_expand_nstring[i] = expand_nstring[i];
2485   save_expand_nlength[i] = expand_nlength[i];
2486   }
2487 return expand_nmax;
2488 }
2489
2490
2491
2492 /*************************************************
2493 *           Restore numerical variables          *
2494 *************************************************/
2495
2496 /* This function restored saved values of numerical strings.
2497
2498 Arguments:
2499   save_expand_nmax      the number of strings to restore
2500   save_expand_string    points to an array of pointers
2501   save_expand_nlength   points to an array of ints
2502
2503 Returns:                nothing
2504 */
2505
2506 static void
2507 restore_expand_strings(int save_expand_nmax, uschar **save_expand_nstring,
2508   int *save_expand_nlength)
2509 {
2510 int i;
2511 expand_nmax = save_expand_nmax;
2512 for (i = 0; i <= expand_nmax; i++)
2513   {
2514   expand_nstring[i] = save_expand_nstring[i];
2515   expand_nlength[i] = save_expand_nlength[i];
2516   }
2517 }
2518
2519
2520
2521
2522
2523 /*************************************************
2524 *            Handle yes/no substrings            *
2525 *************************************************/
2526
2527 /* This function is used by ${if}, ${lookup} and ${extract} to handle the
2528 alternative substrings that depend on whether or not the condition was true,
2529 or the lookup or extraction succeeded. The substrings always have to be
2530 expanded, to check their syntax, but "skipping" is set when the result is not
2531 needed - this avoids unnecessary nested lookups.
2532
2533 Arguments:
2534   skipping       TRUE if we were skipping when this item was reached
2535   yes            TRUE if the first string is to be used, else use the second
2536   save_lookup    a value to put back into lookup_value before the 2nd expansion
2537   sptr           points to the input string pointer
2538   yieldptr       points to the output string pointer
2539   sizeptr        points to the output string size
2540   ptrptr         points to the output string pointer
2541   type           "lookup" or "if" or "extract" or "run", for error message
2542
2543 Returns:         0 OK; lookup_value has been reset to save_lookup
2544                  1 expansion failed
2545                  2 expansion failed because of bracketing error
2546 */
2547
2548 static int
2549 process_yesno(BOOL skipping, BOOL yes, uschar *save_lookup, uschar **sptr,
2550   uschar **yieldptr, int *sizeptr, int *ptrptr, uschar *type)
2551 {
2552 int rc = 0;
2553 uschar *s = *sptr;    /* Local value */
2554 uschar *sub1, *sub2;
2555
2556 /* If there are no following strings, we substitute the contents of $value for
2557 lookups and for extractions in the success case. For the ${if item, the string
2558 "true" is substituted. In the fail case, nothing is substituted for all three
2559 items. */
2560
2561 while (isspace(*s)) s++;
2562 if (*s == '}')
2563   {
2564   if (type[0] == 'i')
2565     {
2566     if (yes) *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, US"true", 4);
2567     }
2568   else
2569     {
2570     if (yes && lookup_value != NULL)
2571       *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, lookup_value,
2572         Ustrlen(lookup_value));
2573     lookup_value = save_lookup;
2574     }
2575   s++;
2576   goto RETURN;
2577   }
2578
2579 /* The first following string must be braced. */
2580
2581 if (*s++ != '{') goto FAILED_CURLY;
2582
2583 /* Expand the first substring. Forced failures are noticed only if we actually
2584 want this string. Set skipping in the call in the fail case (this will always
2585 be the case if we were already skipping). */
2586
2587 sub1 = expand_string_internal(s, TRUE, &s, !yes);
2588 if (sub1 == NULL && (yes || !expand_string_forcedfail)) goto FAILED;
2589 expand_string_forcedfail = FALSE;
2590 if (*s++ != '}') goto FAILED_CURLY;
2591
2592 /* If we want the first string, add it to the output */
2593
2594 if (yes)
2595   *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, sub1, Ustrlen(sub1));
2596
2597 /* If this is called from a lookup or an extract, we want to restore $value to
2598 what it was at the start of the item, so that it has this value during the
2599 second string expansion. For the call from "if" or "run" to this function,
2600 save_lookup is set to lookup_value, so that this statement does nothing. */
2601
2602 lookup_value = save_lookup;
2603
2604 /* There now follows either another substring, or "fail", or nothing. This
2605 time, forced failures are noticed only if we want the second string. We must
2606 set skipping in the nested call if we don't want this string, or if we were
2607 already skipping. */
2608
2609 while (isspace(*s)) s++;
2610 if (*s == '{')
2611   {
2612   sub2 = expand_string_internal(s+1, TRUE, &s, yes || skipping);
2613   if (sub2 == NULL && (!yes || !expand_string_forcedfail)) goto FAILED;
2614   expand_string_forcedfail = FALSE;
2615   if (*s++ != '}') goto FAILED_CURLY;
2616
2617   /* If we want the second string, add it to the output */
2618
2619   if (!yes)
2620     *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, sub2, Ustrlen(sub2));
2621   }
2622
2623 /* If there is no second string, but the word "fail" is present when the use of
2624 the second string is wanted, set a flag indicating it was a forced failure
2625 rather than a syntactic error. Swallow the terminating } in case this is nested
2626 inside another lookup or if or extract. */
2627
2628 else if (*s != '}')
2629   {
2630   uschar name[256];
2631   s = read_name(name, sizeof(name), s, US"_");
2632   if (Ustrcmp(name, "fail") == 0)
2633     {
2634     if (!yes && !skipping)
2635       {
2636       while (isspace(*s)) s++;
2637       if (*s++ != '}') goto FAILED_CURLY;
2638       expand_string_message =
2639         string_sprintf("\"%s\" failed and \"fail\" requested", type);
2640       expand_string_forcedfail = TRUE;
2641       goto FAILED;
2642       }
2643     }
2644   else
2645     {
2646     expand_string_message =
2647       string_sprintf("syntax error in \"%s\" item - \"fail\" expected", type);
2648     goto FAILED;
2649     }
2650   }
2651
2652 /* All we have to do now is to check on the final closing brace. */
2653
2654 while (isspace(*s)) s++;
2655 if (*s++ == '}') goto RETURN;
2656
2657 /* Get here if there is a bracketing failure */
2658
2659 FAILED_CURLY:
2660 rc++;
2661
2662 /* Get here for other failures */
2663
2664 FAILED:
2665 rc++;
2666
2667 /* Update the input pointer value before returning */
2668
2669 RETURN:
2670 *sptr = s;
2671 return rc;
2672 }
2673
2674
2675
2676
2677 /*************************************************
2678 *    Handle MD5 or SHA-1 computation for HMAC    *
2679 *************************************************/
2680
2681 /* These are some wrapping functions that enable the HMAC code to be a bit
2682 cleaner. A good compiler will spot the tail recursion.
2683
2684 Arguments:
2685   type         HMAC_MD5 or HMAC_SHA1
2686   remaining    are as for the cryptographic hash functions
2687
2688 Returns:       nothing
2689 */
2690
2691 static void
2692 chash_start(int type, void *base)
2693 {
2694 if (type == HMAC_MD5)
2695   md5_start((md5 *)base);
2696 else
2697   sha1_start((sha1 *)base);
2698 }
2699
2700 static void
2701 chash_mid(int type, void *base, uschar *string)
2702 {
2703 if (type == HMAC_MD5)
2704   md5_mid((md5 *)base, string);
2705 else
2706   sha1_mid((sha1 *)base, string);
2707 }
2708
2709 static void
2710 chash_end(int type, void *base, uschar *string, int length, uschar *digest)
2711 {
2712 if (type == HMAC_MD5)
2713   md5_end((md5 *)base, string, length, digest);
2714 else
2715   sha1_end((sha1 *)base, string, length, digest);
2716 }
2717
2718
2719
2720
2721
2722 /********************************************************
2723 * prvs: Get last three digits of days since Jan 1, 1970 *
2724 ********************************************************/
2725
2726 /* This is needed to implement the "prvs" BATV reverse
2727    path signing scheme
2728
2729 Argument: integer "days" offset to add or substract to
2730           or from the current number of days.
2731
2732 Returns:  pointer to string containing the last three
2733           digits of the number of days since Jan 1, 1970,
2734           modified by the offset argument, NULL if there
2735           was an error in the conversion.
2736
2737 */
2738
2739 static uschar *
2740 prvs_daystamp(int day_offset)
2741 {
2742 uschar *days = store_get(32);                /* Need at least 24 for cases */
2743 (void)string_format(days, 32, TIME_T_FMT,    /* where TIME_T_FMT is %lld */
2744   (time(NULL) + day_offset*86400)/86400);
2745 return (Ustrlen(days) >= 3) ? &days[Ustrlen(days)-3] : US"100";
2746 }
2747
2748
2749
2750 /********************************************************
2751 *   prvs: perform HMAC-SHA1 computation of prvs bits    *
2752 ********************************************************/
2753
2754 /* This is needed to implement the "prvs" BATV reverse
2755    path signing scheme
2756
2757 Arguments:
2758   address RFC2821 Address to use
2759       key The key to use (must be less than 64 characters
2760           in size)
2761   key_num Single-digit key number to use. Defaults to
2762           '0' when NULL.
2763
2764 Returns:  pointer to string containing the first three
2765           bytes of the final hash in hex format, NULL if
2766           there was an error in the process.
2767 */
2768
2769 static uschar *
2770 prvs_hmac_sha1(uschar *address, uschar *key, uschar *key_num, uschar *daystamp)
2771 {
2772 uschar *hash_source, *p;
2773 int size = 0,offset = 0,i;
2774 sha1 sha1_base;
2775 void *use_base = &sha1_base;
2776 uschar innerhash[20];
2777 uschar finalhash[20];
2778 uschar innerkey[64];
2779 uschar outerkey[64];
2780 uschar *finalhash_hex = store_get(40);
2781
2782 if (key_num == NULL)
2783   key_num = US"0";
2784
2785 if (Ustrlen(key) > 64)
2786   return NULL;
2787
2788 hash_source = string_cat(NULL,&size,&offset,key_num,1);
2789 string_cat(hash_source,&size,&offset,daystamp,3);
2790 string_cat(hash_source,&size,&offset,address,Ustrlen(address));
2791 hash_source[offset] = '\0';
2792
2793 DEBUG(D_expand) debug_printf("prvs: hash source is '%s'\n", hash_source);
2794
2795 memset(innerkey, 0x36, 64);
2796 memset(outerkey, 0x5c, 64);
2797
2798 for (i = 0; i < Ustrlen(key); i++)
2799   {
2800   innerkey[i] ^= key[i];
2801   outerkey[i] ^= key[i];
2802   }
2803
2804 chash_start(HMAC_SHA1, use_base);
2805 chash_mid(HMAC_SHA1, use_base, innerkey);
2806 chash_end(HMAC_SHA1, use_base, hash_source, offset, innerhash);
2807
2808 chash_start(HMAC_SHA1, use_base);
2809 chash_mid(HMAC_SHA1, use_base, outerkey);
2810 chash_end(HMAC_SHA1, use_base, innerhash, 20, finalhash);
2811
2812 p = finalhash_hex;
2813 for (i = 0; i < 3; i++)
2814   {
2815   *p++ = hex_digits[(finalhash[i] & 0xf0) >> 4];
2816   *p++ = hex_digits[finalhash[i] & 0x0f];
2817   }
2818 *p = '\0';
2819
2820 return finalhash_hex;
2821 }
2822
2823
2824
2825
2826 /*************************************************
2827 *        Join a file onto the output string      *
2828 *************************************************/
2829
2830 /* This is used for readfile and after a run expansion. It joins the contents
2831 of a file onto the output string, globally replacing newlines with a given
2832 string (optionally). The file is closed at the end.
2833
2834 Arguments:
2835   f            the FILE
2836   yield        pointer to the expandable string
2837   sizep        pointer to the current size
2838   ptrp         pointer to the current position
2839   eol          newline replacement string, or NULL
2840
2841 Returns:       new value of string pointer
2842 */
2843
2844 static uschar *
2845 cat_file(FILE *f, uschar *yield, int *sizep, int *ptrp, uschar *eol)
2846 {
2847 int eollen;
2848 uschar buffer[1024];
2849
2850 eollen = (eol == NULL)? 0 : Ustrlen(eol);
2851
2852 while (Ufgets(buffer, sizeof(buffer), f) != NULL)
2853   {
2854   int len = Ustrlen(buffer);
2855   if (eol != NULL && buffer[len-1] == '\n') len--;
2856   yield = string_cat(yield, sizep, ptrp, buffer, len);
2857   if (buffer[len] != 0)
2858     yield = string_cat(yield, sizep, ptrp, eol, eollen);
2859   }
2860
2861 if (yield != NULL) yield[*ptrp] = 0;
2862
2863 return yield;
2864 }
2865
2866
2867
2868
2869 /*************************************************
2870 *          Evaluate numeric expression           *
2871 *************************************************/
2872
2873 /* This is a set of mutually recursive functions that evaluate an arithmetic
2874 expression involving + - * / % & | ^ ~ << >> and parentheses. The only one of
2875 these functions that is called from elsewhere is eval_expr, whose interface is:
2876
2877 Arguments:
2878   sptr        pointer to the pointer to the string - gets updated
2879   decimal     TRUE if numbers are to be assumed decimal
2880   error       pointer to where to put an error message - must be NULL on input
2881   endket      TRUE if ')' must terminate - FALSE for external call
2882
2883 Returns:      on success: the value of the expression, with *error still NULL
2884               on failure: an undefined value, with *error = a message
2885 */
2886
2887 static int eval_op_or(uschar **, BOOL, uschar **);
2888
2889
2890 static int
2891 eval_expr(uschar **sptr, BOOL decimal, uschar **error, BOOL endket)
2892 {
2893 uschar *s = *sptr;
2894 int x = eval_op_or(&s, decimal, error);
2895 if (*error == NULL)
2896   {
2897   if (endket)
2898     {
2899     if (*s != ')')
2900       *error = US"expecting closing parenthesis";
2901     else
2902       while (isspace(*(++s)));
2903     }
2904   else if (*s != 0) *error = US"expecting operator";
2905   }
2906 *sptr = s;
2907 return x;
2908 }
2909
2910
2911 static int
2912 eval_number(uschar **sptr, BOOL decimal, uschar **error)
2913 {
2914 register int c;
2915 int n;
2916 uschar *s = *sptr;
2917 while (isspace(*s)) s++;
2918 c = *s;
2919 if (isdigit(c))
2920   {
2921   int count;
2922   (void)sscanf(CS s, (decimal? "%d%n" : "%i%n"), &n, &count);
2923   s += count;
2924   if (tolower(*s) == 'k') { n *= 1024; s++; }
2925     else if (tolower(*s) == 'm') { n *= 1024*1024; s++; }
2926   while (isspace (*s)) s++;
2927   }
2928 else if (c == '(')
2929   {
2930   s++;
2931   n = eval_expr(&s, decimal, error, 1);
2932   }
2933 else
2934   {
2935   *error = US"expecting number or opening parenthesis";
2936   n = 0;
2937   }
2938 *sptr = s;
2939 return n;
2940 }
2941
2942
2943 static int eval_op_unary(uschar **sptr, BOOL decimal, uschar **error)
2944 {
2945 uschar *s = *sptr;
2946 int x;
2947 while (isspace(*s)) s++;
2948 if (*s == '+' || *s == '-' || *s == '~')
2949   {
2950   int op = *s++;
2951   x = eval_op_unary(&s, decimal, error);
2952   if (op == '-') x = -x;
2953     else if (op == '~') x = ~x;
2954   }
2955 else
2956   {
2957   x = eval_number(&s, decimal, error);
2958   }
2959 *sptr = s;
2960 return x;
2961 }
2962
2963
2964 static int eval_op_mult(uschar **sptr, BOOL decimal, uschar **error)
2965 {
2966 uschar *s = *sptr;
2967 int x = eval_op_unary(&s, decimal, error);
2968 if (*error == NULL)
2969   {
2970   while (*s == '*' || *s == '/' || *s == '%')
2971     {
2972     int op = *s++;
2973     int y = eval_op_unary(&s, decimal, error);
2974     if (*error != NULL) break;
2975     if (op == '*') x *= y;
2976       else if (op == '/') x /= y;
2977       else x %= y;
2978     }
2979   }
2980 *sptr = s;
2981 return x;
2982 }
2983
2984
2985 static int eval_op_sum(uschar **sptr, BOOL decimal, uschar **error)
2986 {
2987 uschar *s = *sptr;
2988 int x = eval_op_mult(&s, decimal, error);
2989 if (*error == NULL)
2990   {
2991   while (*s == '+' || *s == '-')
2992     {
2993     int op = *s++;
2994     int y = eval_op_mult(&s, decimal, error);
2995     if (*error != NULL) break;
2996     if (op == '+') x += y; else x -= y;
2997     }
2998   }
2999 *sptr = s;
3000 return x;
3001 }
3002
3003
3004 static int eval_op_shift(uschar **sptr, BOOL decimal, uschar **error)
3005 {
3006 uschar *s = *sptr;
3007 int x = eval_op_sum(&s, decimal, error);
3008 if (*error == NULL)
3009   {
3010   while ((*s == '<' || *s == '>') && s[1] == s[0])
3011     {
3012     int y;
3013     int op = *s++;
3014     s++;
3015     y = eval_op_sum(&s, decimal, error);
3016     if (*error != NULL) break;
3017     if (op == '<') x <<= y; else x >>= y;
3018     }
3019   }
3020 *sptr = s;
3021 return x;
3022 }
3023
3024
3025 static int eval_op_and(uschar **sptr, BOOL decimal, uschar **error)
3026 {
3027 uschar *s = *sptr;
3028 int x = eval_op_shift(&s, decimal, error);
3029 if (*error == NULL)
3030   {
3031   while (*s == '&')
3032     {
3033     int y;
3034     s++;
3035     y = eval_op_shift(&s, decimal, error);
3036     if (*error != NULL) break;
3037     x &= y;
3038     }
3039   }
3040 *sptr = s;
3041 return x;
3042 }
3043
3044
3045 static int eval_op_xor(uschar **sptr, BOOL decimal, uschar **error)
3046 {
3047 uschar *s = *sptr;
3048 int x = eval_op_and(&s, decimal, error);
3049 if (*error == NULL)
3050   {
3051   while (*s == '^')
3052     {
3053     int y;
3054     s++;
3055     y = eval_op_and(&s, decimal, error);
3056     if (*error != NULL) break;
3057     x ^= y;
3058     }
3059   }
3060 *sptr = s;
3061 return x;
3062 }
3063
3064
3065 static int eval_op_or(uschar **sptr, BOOL decimal, uschar **error)
3066 {
3067 uschar *s = *sptr;
3068 int x = eval_op_xor(&s, decimal, error);
3069 if (*error == NULL)
3070   {
3071   while (*s == '|')
3072     {
3073     int y;
3074     s++;
3075     y = eval_op_xor(&s, decimal, error);
3076     if (*error != NULL) break;
3077     x |= y;
3078     }
3079   }
3080 *sptr = s;
3081 return x;
3082 }
3083
3084
3085
3086 /*************************************************
3087 *                 Expand string                  *
3088 *************************************************/
3089
3090 /* Returns either an unchanged string, or the expanded string in stacking pool
3091 store. Interpreted sequences are:
3092
3093    \...                    normal escaping rules
3094    $name                   substitutes the variable
3095    ${name}                 ditto
3096    ${op:string}            operates on the expanded string value
3097    ${item{arg1}{arg2}...}  expands the args and then does the business
3098                              some literal args are not enclosed in {}
3099
3100 There are now far too many operators and item types to make it worth listing
3101 them here in detail any more.
3102
3103 We use an internal routine recursively to handle embedded substrings. The
3104 external function follows. The yield is NULL if the expansion failed, and there
3105 are two cases: if something collapsed syntactically, or if "fail" was given
3106 as the action on a lookup failure. These can be distinguised by looking at the
3107 variable expand_string_forcedfail, which is TRUE in the latter case.
3108
3109 The skipping flag is set true when expanding a substring that isn't actually
3110 going to be used (after "if" or "lookup") and it prevents lookups from
3111 happening lower down.
3112
3113 Store usage: At start, a store block of the length of the input plus 64
3114 is obtained. This is expanded as necessary by string_cat(), which might have to
3115 get a new block, or might be able to expand the original. At the end of the
3116 function we can release any store above that portion of the yield block that
3117 was actually used. In many cases this will be optimal.
3118
3119 However: if the first item in the expansion is a variable name or header name,
3120 we reset the store before processing it; if the result is in fresh store, we
3121 use that without copying. This is helpful for expanding strings like
3122 $message_headers which can get very long.
3123
3124 Arguments:
3125   string         the string to be expanded
3126   ket_ends       true if expansion is to stop at }
3127   left           if not NULL, a pointer to the first character after the
3128                  expansion is placed here (typically used with ket_ends)
3129   skipping       TRUE for recursive calls when the value isn't actually going
3130                  to be used (to allow for optimisation)
3131
3132 Returns:         NULL if expansion fails:
3133                    expand_string_forcedfail is set TRUE if failure was forced
3134                    expand_string_message contains a textual error message
3135                  a pointer to the expanded string on success
3136 */
3137
3138 static uschar *
3139 expand_string_internal(uschar *string, BOOL ket_ends, uschar **left,
3140   BOOL skipping)
3141 {
3142 int ptr = 0;
3143 int size = Ustrlen(string)+ 64;
3144 int item_type;
3145 uschar *yield = store_get(size);
3146 uschar *s = string;
3147 uschar *save_expand_nstring[EXPAND_MAXN+1];
3148 int save_expand_nlength[EXPAND_MAXN+1];
3149
3150 expand_string_forcedfail = FALSE;
3151 expand_string_message = US"";
3152
3153 while (*s != 0)
3154   {
3155   uschar *value;
3156   uschar name[256];
3157
3158   /* \ escapes the next character, which must exist, or else
3159   the expansion fails. There's a special escape, \N, which causes
3160   copying of the subject verbatim up to the next \N. Otherwise,
3161   the escapes are the standard set. */
3162
3163   if (*s == '\\')
3164     {
3165     if (s[1] == 0)
3166       {
3167       expand_string_message = US"\\ at end of string";
3168       goto EXPAND_FAILED;
3169       }
3170
3171     if (s[1] == 'N')
3172       {
3173       uschar *t = s + 2;
3174       for (s = t; *s != 0; s++) if (*s == '\\' && s[1] == 'N') break;
3175       yield = string_cat(yield, &size, &ptr, t, s - t);
3176       if (*s != 0) s += 2;
3177       }
3178
3179     else
3180       {
3181       uschar ch[1];
3182       ch[0] = string_interpret_escape(&s);
3183       s++;
3184       yield = string_cat(yield, &size, &ptr, ch, 1);
3185       }
3186
3187     continue;
3188     }
3189
3190   /* Anything other than $ is just copied verbatim, unless we are
3191   looking for a terminating } character. */
3192
3193   if (ket_ends && *s == '}') break;
3194
3195   if (*s != '$')
3196     {
3197     yield = string_cat(yield, &size, &ptr, s++, 1);
3198     continue;
3199     }
3200
3201   /* No { after the $ - must be a plain name or a number for string
3202   match variable. There has to be a fudge for variables that are the
3203   names of header fields preceded by "$header_" because header field
3204   names can contain any printing characters except space and colon.
3205   For those that don't like typing this much, "$h_" is a synonym for
3206   "$header_". A non-existent header yields a NULL value; nothing is
3207   inserted. */
3208
3209   if (isalpha((*(++s))))
3210     {
3211     int len;
3212     int newsize = 0;
3213
3214     s = read_name(name, sizeof(name), s, US"_");
3215
3216     /* If this is the first thing to be expanded, release the pre-allocated
3217     buffer. */
3218
3219     if (ptr == 0 && yield != NULL)
3220       {
3221       store_reset(yield);
3222       yield = NULL;
3223       size = 0;
3224       }
3225
3226     /* Header */
3227
3228     if (Ustrncmp(name, "h_", 2) == 0 ||
3229         Ustrncmp(name, "rh_", 3) == 0 ||
3230         Ustrncmp(name, "bh_", 3) == 0 ||
3231         Ustrncmp(name, "header_", 7) == 0 ||
3232         Ustrncmp(name, "rheader_", 8) == 0 ||
3233         Ustrncmp(name, "bheader_", 8) == 0)
3234       {
3235       BOOL want_raw = (name[0] == 'r')? TRUE : FALSE;
3236       uschar *charset = (name[0] == 'b')? NULL : headers_charset;
3237       s = read_header_name(name, sizeof(name), s);
3238       value = find_header(name, FALSE, &newsize, want_raw, charset);
3239
3240       /* If we didn't find the header, and the header contains a closing brace
3241       character, this may be a user error where the terminating colon
3242       has been omitted. Set a flag to adjust the error message in this case.
3243       But there is no error here - nothing gets inserted. */
3244
3245       if (value == NULL)
3246         {
3247         if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
3248         continue;
3249         }
3250       }
3251
3252     /* Variable */
3253
3254     else
3255       {
3256       value = find_variable(name, FALSE, skipping, &newsize);
3257       if (value == NULL)
3258         {
3259         expand_string_message =
3260           string_sprintf("unknown variable name \"%s\"", name);
3261           check_variable_error_message(name);
3262         goto EXPAND_FAILED;
3263         }
3264       }
3265
3266     /* If the data is known to be in a new buffer, newsize will be set to the
3267     size of that buffer. If this is the first thing in an expansion string,
3268     yield will be NULL; just point it at the new store instead of copying. Many
3269     expansion strings contain just one reference, so this is a useful
3270     optimization, especially for humungous headers. */
3271
3272     len = Ustrlen(value);
3273     if (yield == NULL && newsize != 0)
3274       {
3275       yield = value;
3276       size = newsize;
3277       ptr = len;
3278       }
3279     else yield = string_cat(yield, &size, &ptr, value, len);
3280
3281     continue;
3282     }
3283
3284   if (isdigit(*s))
3285     {
3286     int n;
3287     s = read_number(&n, s);
3288     if (n >= 0 && n <= expand_nmax)
3289       yield = string_cat(yield, &size, &ptr, expand_nstring[n],
3290         expand_nlength[n]);
3291     continue;
3292     }
3293
3294   /* Otherwise, if there's no '{' after $ it's an error. */
3295
3296   if (*s != '{')
3297     {
3298     expand_string_message = US"$ not followed by letter, digit, or {";
3299     goto EXPAND_FAILED;
3300     }
3301
3302   /* After { there can be various things, but they all start with
3303   an initial word, except for a number for a string match variable. */
3304
3305   if (isdigit((*(++s))))
3306     {
3307     int n;
3308     s = read_number(&n, s);
3309     if (*s++ != '}')
3310       {
3311       expand_string_message = US"} expected after number";
3312       goto EXPAND_FAILED;
3313       }
3314     if (n >= 0 && n <= expand_nmax)
3315       yield = string_cat(yield, &size, &ptr, expand_nstring[n],
3316         expand_nlength[n]);
3317     continue;
3318     }
3319
3320   if (!isalpha(*s))
3321     {
3322     expand_string_message = US"letter or digit expected after ${";
3323     goto EXPAND_FAILED;
3324     }
3325
3326   /* Allow "-" in names to cater for substrings with negative
3327   arguments. Since we are checking for known names after { this is
3328   OK. */
3329
3330   s = read_name(name, sizeof(name), s, US"_-");
3331   item_type = chop_match(name, item_table, sizeof(item_table)/sizeof(uschar *));
3332
3333   switch(item_type)
3334     {
3335     /* Handle conditionals - preserve the values of the numerical expansion
3336     variables in case they get changed by a regular expression match in the
3337     condition. If not, they retain their external settings. At the end
3338     of this "if" section, they get restored to their previous values. */
3339
3340     case EITEM_IF:
3341       {
3342       BOOL cond = FALSE;
3343       uschar *next_s;
3344       int save_expand_nmax =
3345         save_expand_strings(save_expand_nstring, save_expand_nlength);
3346
3347       while (isspace(*s)) s++;
3348       next_s = eval_condition(s, skipping? NULL : &cond);
3349       if (next_s == NULL) goto EXPAND_FAILED;  /* message already set */
3350
3351       DEBUG(D_expand)
3352         debug_printf("condition: %.*s\n   result: %s\n", (int)(next_s - s), s,
3353           cond? "true" : "false");
3354
3355       s = next_s;
3356
3357       /* The handling of "yes" and "no" result strings is now in a separate
3358       function that is also used by ${lookup} and ${extract} and ${run}. */
3359
3360       switch(process_yesno(
3361                skipping,                     /* were previously skipping */
3362                cond,                         /* success/failure indicator */
3363                lookup_value,                 /* value to reset for string2 */
3364                &s,                           /* input pointer */
3365                &yield,                       /* output pointer */
3366                &size,                        /* output size */
3367                &ptr,                         /* output current point */
3368                US"if"))                      /* condition type */
3369         {
3370         case 1: goto EXPAND_FAILED;          /* when all is well, the */
3371         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
3372         }
3373
3374       /* Restore external setting of expansion variables for continuation
3375       at this level. */
3376
3377       restore_expand_strings(save_expand_nmax, save_expand_nstring,
3378         save_expand_nlength);
3379       continue;
3380       }
3381
3382     /* Handle database lookups unless locked out. If "skipping" is TRUE, we are
3383     expanding an internal string that isn't actually going to be used. All we
3384     need to do is check the syntax, so don't do a lookup at all. Preserve the
3385     values of the numerical expansion variables in case they get changed by a
3386     partial lookup. If not, they retain their external settings. At the end
3387     of this "lookup" section, they get restored to their previous values. */
3388
3389     case EITEM_LOOKUP:
3390       {
3391       int stype, partial, affixlen, starflags;
3392       int expand_setup = 0;
3393       int nameptr = 0;
3394       uschar *key, *filename, *affix;
3395       uschar *save_lookup_value = lookup_value;
3396       int save_expand_nmax =
3397         save_expand_strings(save_expand_nstring, save_expand_nlength);
3398
3399       if ((expand_forbid & RDO_LOOKUP) != 0)
3400         {
3401         expand_string_message = US"lookup expansions are not permitted";
3402         goto EXPAND_FAILED;
3403         }
3404
3405       /* Get the key we are to look up for single-key+file style lookups.
3406       Otherwise set the key NULL pro-tem. */
3407
3408       while (isspace(*s)) s++;
3409       if (*s == '{')
3410         {
3411         key = expand_string_internal(s+1, TRUE, &s, skipping);
3412         if (key == NULL) goto EXPAND_FAILED;
3413         if (*s++ != '}') goto EXPAND_FAILED_CURLY;
3414         while (isspace(*s)) s++;
3415         }
3416       else key = NULL;
3417
3418       /* Find out the type of database */
3419
3420       if (!isalpha(*s))
3421         {
3422         expand_string_message = US"missing lookup type";
3423         goto EXPAND_FAILED;
3424         }
3425
3426       /* The type is a string that may contain special characters of various
3427       kinds. Allow everything except space or { to appear; the actual content
3428       is checked by search_findtype_partial. */
3429
3430       while (*s != 0 && *s != '{' && !isspace(*s))
3431         {
3432         if (nameptr < sizeof(name) - 1) name[nameptr++] = *s;
3433         s++;
3434         }
3435       name[nameptr] = 0;
3436       while (isspace(*s)) s++;
3437
3438       /* Now check for the individual search type and any partial or default
3439       options. Only those types that are actually in the binary are valid. */
3440
3441       stype = search_findtype_partial(name, &partial, &affix, &affixlen,
3442         &starflags);
3443       if (stype < 0)
3444         {
3445         expand_string_message = search_error_message;
3446         goto EXPAND_FAILED;
3447         }
3448
3449       /* Check that a key was provided for those lookup types that need it,
3450       and was not supplied for those that use the query style. */
3451
3452       if (!mac_islookup(stype, lookup_querystyle|lookup_absfilequery))
3453         {
3454         if (key == NULL)
3455           {
3456           expand_string_message = string_sprintf("missing {key} for single-"
3457             "key \"%s\" lookup", name);
3458           goto EXPAND_FAILED;
3459           }
3460         }
3461       else
3462         {
3463         if (key != NULL)
3464           {
3465           expand_string_message = string_sprintf("a single key was given for "
3466             "lookup type \"%s\", which is not a single-key lookup type", name);
3467           goto EXPAND_FAILED;
3468           }
3469         }
3470
3471       /* Get the next string in brackets and expand it. It is the file name for
3472       single-key+file lookups, and the whole query otherwise. In the case of
3473       queries that also require a file name (e.g. sqlite), the file name comes
3474       first. */
3475
3476       if (*s != '{') goto EXPAND_FAILED_CURLY;
3477       filename = expand_string_internal(s+1, TRUE, &s, skipping);
3478       if (filename == NULL) goto EXPAND_FAILED;
3479       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
3480       while (isspace(*s)) s++;
3481
3482       /* If this isn't a single-key+file lookup, re-arrange the variables
3483       to be appropriate for the search_ functions. For query-style lookups,
3484       there is just a "key", and no file name. For the special query-style +
3485       file types, the query (i.e. "key") starts with a file name. */
3486
3487       if (key == NULL)
3488         {
3489         while (isspace(*filename)) filename++;
3490         key = filename;
3491
3492         if (mac_islookup(stype, lookup_querystyle))
3493           {
3494           filename = NULL;
3495           }
3496         else
3497           {
3498           if (*filename != '/')
3499             {
3500             expand_string_message = string_sprintf(
3501               "absolute file name expected for \"%s\" lookup", name);
3502             goto EXPAND_FAILED;
3503             }
3504           while (*key != 0 && !isspace(*key)) key++;
3505           if (*key != 0) *key++ = 0;
3506           }
3507         }
3508
3509       /* If skipping, don't do the next bit - just lookup_value == NULL, as if
3510       the entry was not found. Note that there is no search_close() function.
3511       Files are left open in case of re-use. At suitable places in higher logic,
3512       search_tidyup() is called to tidy all open files. This can save opening
3513       the same file several times. However, files may also get closed when
3514       others are opened, if too many are open at once. The rule is that a
3515       handle should not be used after a second search_open().
3516
3517       Request that a partial search sets up $1 and maybe $2 by passing
3518       expand_setup containing zero. If its value changes, reset expand_nmax,
3519       since new variables will have been set. Note that at the end of this
3520       "lookup" section, the old numeric variables are restored. */
3521
3522       if (skipping)
3523         lookup_value = NULL;
3524       else
3525         {
3526         void *handle = search_open(filename, stype, 0, NULL, NULL);
3527         if (handle == NULL)
3528           {
3529           expand_string_message = search_error_message;
3530           goto EXPAND_FAILED;
3531           }
3532         lookup_value = search_find(handle, filename, key, partial, affix,
3533           affixlen, starflags, &expand_setup);
3534         if (search_find_defer)
3535           {
3536           expand_string_message =
3537             string_sprintf("lookup of \"%s\" gave DEFER: %s", key,
3538               search_error_message);
3539           goto EXPAND_FAILED;
3540           }
3541         if (expand_setup > 0) expand_nmax = expand_setup;
3542         }
3543
3544       /* The handling of "yes" and "no" result strings is now in a separate
3545       function that is also used by ${if} and ${extract}. */
3546
3547       switch(process_yesno(
3548                skipping,                     /* were previously skipping */
3549                lookup_value != NULL,         /* success/failure indicator */
3550                save_lookup_value,            /* value to reset for string2 */
3551                &s,                           /* input pointer */
3552                &yield,                       /* output pointer */
3553                &size,                        /* output size */
3554                &ptr,                         /* output current point */
3555                US"lookup"))                  /* condition type */
3556         {
3557         case 1: goto EXPAND_FAILED;          /* when all is well, the */
3558         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
3559         }
3560
3561       /* Restore external setting of expansion variables for carrying on
3562       at this level, and continue. */
3563
3564       restore_expand_strings(save_expand_nmax, save_expand_nstring,
3565         save_expand_nlength);
3566       continue;
3567       }
3568
3569     /* If Perl support is configured, handle calling embedded perl subroutines,
3570     unless locked out at this time. Syntax is ${perl{sub}} or ${perl{sub}{arg}}
3571     or ${perl{sub}{arg1}{arg2}} or up to a maximum of EXIM_PERL_MAX_ARGS
3572     arguments (defined below). */
3573
3574     #define EXIM_PERL_MAX_ARGS 8
3575
3576     case EITEM_PERL:
3577     #ifndef EXIM_PERL
3578     expand_string_message = US"\"${perl\" encountered, but this facility "
3579       "is not included in this binary";
3580     goto EXPAND_FAILED;
3581
3582     #else   /* EXIM_PERL */
3583       {
3584       uschar *sub_arg[EXIM_PERL_MAX_ARGS + 2];
3585       uschar *new_yield;
3586
3587       if ((expand_forbid & RDO_PERL) != 0)
3588         {
3589         expand_string_message = US"Perl calls are not permitted";
3590         goto EXPAND_FAILED;
3591         }
3592
3593       switch(read_subs(sub_arg, EXIM_PERL_MAX_ARGS + 1, 1, &s, skipping, TRUE,
3594            US"perl"))
3595         {
3596         case 1: goto EXPAND_FAILED_CURLY;
3597         case 2:
3598         case 3: goto EXPAND_FAILED;
3599         }
3600
3601       /* If skipping, we don't actually do anything */
3602
3603       if (skipping) continue;
3604
3605       /* Start the interpreter if necessary */
3606
3607       if (!opt_perl_started)
3608         {
3609         uschar *initerror;
3610         if (opt_perl_startup == NULL)
3611           {
3612           expand_string_message = US"A setting of perl_startup is needed when "
3613             "using the Perl interpreter";
3614           goto EXPAND_FAILED;
3615           }
3616         DEBUG(D_any) debug_printf("Starting Perl interpreter\n");
3617         initerror = init_perl(opt_perl_startup);
3618         if (initerror != NULL)
3619           {
3620           expand_string_message =
3621             string_sprintf("error in perl_startup code: %s\n", initerror);
3622           goto EXPAND_FAILED;
3623           }
3624         opt_perl_started = TRUE;
3625         }
3626
3627       /* Call the function */
3628
3629       sub_arg[EXIM_PERL_MAX_ARGS + 1] = NULL;
3630       new_yield = call_perl_cat(yield, &size, &ptr, &expand_string_message,
3631         sub_arg[0], sub_arg + 1);
3632
3633       /* NULL yield indicates failure; if the message pointer has been set to
3634       NULL, the yield was undef, indicating a forced failure. Otherwise the
3635       message will indicate some kind of Perl error. */
3636
3637       if (new_yield == NULL)
3638         {
3639         if (expand_string_message == NULL)
3640           {
3641           expand_string_message =
3642             string_sprintf("Perl subroutine \"%s\" returned undef to force "
3643               "failure", sub_arg[0]);
3644           expand_string_forcedfail = TRUE;
3645           }
3646         goto EXPAND_FAILED;
3647         }
3648
3649       /* Yield succeeded. Ensure forcedfail is unset, just in case it got
3650       set during a callback from Perl. */
3651
3652       expand_string_forcedfail = FALSE;
3653       yield = new_yield;
3654       continue;
3655       }
3656     #endif /* EXIM_PERL */
3657
3658     /* Transform email address to "prvs" scheme to use
3659        as BATV-signed return path */
3660
3661     case EITEM_PRVS:
3662       {
3663       uschar *sub_arg[3];
3664       uschar *p,*domain;
3665
3666       switch(read_subs(sub_arg, 3, 2, &s, skipping, TRUE, US"prvs"))
3667         {
3668         case 1: goto EXPAND_FAILED_CURLY;
3669         case 2:
3670         case 3: goto EXPAND_FAILED;
3671         }
3672
3673       /* If skipping, we don't actually do anything */
3674       if (skipping) continue;
3675
3676       /* sub_arg[0] is the address */
3677       domain = Ustrrchr(sub_arg[0],'@');
3678       if ( (domain == NULL) || (domain == sub_arg[0]) || (Ustrlen(domain) == 1) )
3679         {
3680         expand_string_message = US"prvs first argument must be a qualified email address";
3681         goto EXPAND_FAILED;
3682         }
3683
3684       /* Calculate the hash. The second argument must be a single-digit
3685       key number, or unset. */
3686
3687       if (sub_arg[2] != NULL &&
3688           (!isdigit(sub_arg[2][0]) || sub_arg[2][1] != 0))
3689         {
3690         expand_string_message = US"prvs second argument must be a single digit";
3691         goto EXPAND_FAILED;
3692         }
3693
3694       p = prvs_hmac_sha1(sub_arg[0],sub_arg[1],sub_arg[2],prvs_daystamp(7));
3695       if (p == NULL)
3696         {
3697         expand_string_message = US"prvs hmac-sha1 conversion failed";
3698         goto EXPAND_FAILED;
3699         }
3700
3701       /* Now separate the domain from the local part */
3702       *domain++ = '\0';
3703
3704       yield = string_cat(yield,&size,&ptr,US"prvs=",5);
3705       string_cat(yield,&size,&ptr,(sub_arg[2] != NULL) ? sub_arg[2] : US"0", 1);
3706       string_cat(yield,&size,&ptr,prvs_daystamp(7),3);
3707       string_cat(yield,&size,&ptr,p,6);
3708       string_cat(yield,&size,&ptr,US"=",1);
3709       string_cat(yield,&size,&ptr,sub_arg[0],Ustrlen(sub_arg[0]));
3710       string_cat(yield,&size,&ptr,US"@",1);
3711       string_cat(yield,&size,&ptr,domain,Ustrlen(domain));
3712
3713       continue;
3714       }
3715
3716     /* Check a prvs-encoded address for validity */
3717
3718     case EITEM_PRVSCHECK:
3719       {
3720       uschar *sub_arg[3];
3721       int mysize = 0, myptr = 0;
3722       const pcre *re;
3723       uschar *p;
3724
3725       /* TF: Ugliness: We want to expand parameter 1 first, then set
3726          up expansion variables that are used in the expansion of
3727          parameter 2. So we clone the string for the first
3728          expansion, where we only expand parameter 1.
3729
3730          PH: Actually, that isn't necessary. The read_subs() function is
3731          designed to work this way for the ${if and ${lookup expansions. I've
3732          tidied the code.
3733       */
3734
3735       /* Reset expansion variables */
3736       prvscheck_result = NULL;
3737       prvscheck_address = NULL;
3738       prvscheck_keynum = NULL;
3739
3740       switch(read_subs(sub_arg, 1, 1, &s, skipping, FALSE, US"prvs"))
3741         {
3742         case 1: goto EXPAND_FAILED_CURLY;
3743         case 2:
3744         case 3: goto EXPAND_FAILED;
3745         }
3746
3747       re = regex_must_compile(US"^prvs\\=([0-9])([0-9]{3})([A-F0-9]{6})\\=(.+)\\@(.+)$",
3748                               TRUE,FALSE);
3749
3750       if (regex_match_and_setup(re,sub_arg[0],0,-1))
3751         {
3752         uschar *local_part = string_copyn(expand_nstring[4],expand_nlength[4]);
3753         uschar *key_num = string_copyn(expand_nstring[1],expand_nlength[1]);
3754         uschar *daystamp = string_copyn(expand_nstring[2],expand_nlength[2]);
3755         uschar *hash = string_copyn(expand_nstring[3],expand_nlength[3]);
3756         uschar *domain = string_copyn(expand_nstring[5],expand_nlength[5]);
3757
3758         DEBUG(D_expand) debug_printf("prvscheck localpart: %s\n", local_part);
3759         DEBUG(D_expand) debug_printf("prvscheck key number: %s\n", key_num);
3760         DEBUG(D_expand) debug_printf("prvscheck daystamp: %s\n", daystamp);
3761         DEBUG(D_expand) debug_printf("prvscheck hash: %s\n", hash);
3762         DEBUG(D_expand) debug_printf("prvscheck domain: %s\n", domain);
3763
3764         /* Set up expansion variables */
3765         prvscheck_address = string_cat(NULL, &mysize, &myptr, local_part, Ustrlen(local_part));
3766         string_cat(prvscheck_address,&mysize,&myptr,US"@",1);
3767         string_cat(prvscheck_address,&mysize,&myptr,domain,Ustrlen(domain));
3768         prvscheck_address[myptr] = '\0';
3769         prvscheck_keynum = string_copy(key_num);
3770
3771         /* Now expand the second argument */
3772         switch(read_subs(sub_arg, 1, 1, &s, skipping, FALSE, US"prvs"))
3773           {
3774           case 1: goto EXPAND_FAILED_CURLY;
3775           case 2:
3776           case 3: goto EXPAND_FAILED;
3777           }
3778
3779         /* Now we have the key and can check the address. */
3780
3781         p = prvs_hmac_sha1(prvscheck_address, sub_arg[0], prvscheck_keynum,
3782           daystamp);
3783
3784         if (p == NULL)
3785           {
3786           expand_string_message = US"hmac-sha1 conversion failed";
3787           goto EXPAND_FAILED;
3788           }
3789
3790         DEBUG(D_expand) debug_printf("prvscheck: received hash is %s\n", hash);
3791         DEBUG(D_expand) debug_printf("prvscheck:      own hash is %s\n", p);
3792
3793         if (Ustrcmp(p,hash) == 0)
3794           {
3795           /* Success, valid BATV address. Now check the expiry date. */
3796           uschar *now = prvs_daystamp(0);
3797           unsigned int inow = 0,iexpire = 1;
3798
3799           (void)sscanf(CS now,"%u",&inow);
3800           (void)sscanf(CS daystamp,"%u",&iexpire);
3801
3802           /* When "iexpire" is < 7, a "flip" has occured.
3803              Adjust "inow" accordingly. */
3804           if ( (iexpire < 7) && (inow >= 993) ) inow = 0;
3805
3806           if (iexpire > inow)
3807             {
3808             prvscheck_result = US"1";
3809             DEBUG(D_expand) debug_printf("prvscheck: success, $pvrs_result set to 1\n");
3810             }
3811             else
3812             {
3813             prvscheck_result = NULL;
3814             DEBUG(D_expand) debug_printf("prvscheck: signature expired, $pvrs_result unset\n");
3815             }
3816           }
3817         else
3818           {
3819           prvscheck_result = NULL;
3820           DEBUG(D_expand) debug_printf("prvscheck: hash failure, $pvrs_result unset\n");
3821           }
3822
3823         /* Now expand the final argument. We leave this till now so that
3824         it can include $prvscheck_result. */
3825
3826         switch(read_subs(sub_arg, 1, 0, &s, skipping, TRUE, US"prvs"))
3827           {
3828           case 1: goto EXPAND_FAILED_CURLY;
3829           case 2:
3830           case 3: goto EXPAND_FAILED;
3831           }
3832
3833         if (sub_arg[0] == NULL || *sub_arg[0] == '\0')
3834           yield = string_cat(yield,&size,&ptr,prvscheck_address,Ustrlen(prvscheck_address));
3835         else
3836           yield = string_cat(yield,&size,&ptr,sub_arg[0],Ustrlen(sub_arg[0]));
3837
3838         /* Reset the "internal" variables afterwards, because they are in
3839         dynamic store that will be reclaimed if the expansion succeeded. */
3840
3841         prvscheck_address = NULL;
3842         prvscheck_keynum = NULL;
3843         }
3844       else
3845         {
3846         /* Does not look like a prvs encoded address, return the empty string.
3847            We need to make sure all subs are expanded first, so as to skip over
3848            the entire item. */
3849
3850         switch(read_subs(sub_arg, 2, 1, &s, skipping, TRUE, US"prvs"))
3851           {
3852           case 1: goto EXPAND_FAILED_CURLY;
3853           case 2:
3854           case 3: goto EXPAND_FAILED;
3855           }
3856         }
3857
3858       continue;
3859       }
3860
3861     /* Handle "readfile" to insert an entire file */
3862
3863     case EITEM_READFILE:
3864       {
3865       FILE *f;
3866       uschar *sub_arg[2];
3867
3868       if ((expand_forbid & RDO_READFILE) != 0)
3869         {
3870         expand_string_message = US"file insertions are not permitted";
3871         goto EXPAND_FAILED;
3872         }
3873
3874       switch(read_subs(sub_arg, 2, 1, &s, skipping, TRUE, US"readfile"))
3875         {
3876         case 1: goto EXPAND_FAILED_CURLY;
3877         case 2:
3878         case 3: goto EXPAND_FAILED;
3879         }
3880
3881       /* If skipping, we don't actually do anything */
3882
3883       if (skipping) continue;
3884
3885       /* Open the file and read it */
3886
3887       f = Ufopen(sub_arg[0], "rb");
3888       if (f == NULL)
3889         {
3890         expand_string_message = string_open_failed(errno, "%s", sub_arg[0]);
3891         goto EXPAND_FAILED;
3892         }
3893
3894       yield = cat_file(f, yield, &size, &ptr, sub_arg[1]);
3895       (void)fclose(f);
3896       continue;
3897       }
3898
3899     /* Handle "readsocket" to insert data from a Unix domain socket */
3900
3901     case EITEM_READSOCK:
3902       {
3903       int fd;
3904       int timeout = 5;
3905       int save_ptr = ptr;
3906       FILE *f;
3907       struct sockaddr_un sockun;         /* don't call this "sun" ! */
3908       uschar *arg;
3909       uschar *sub_arg[4];
3910
3911       if ((expand_forbid & RDO_READSOCK) != 0)
3912         {
3913         expand_string_message = US"socket insertions are not permitted";
3914         goto EXPAND_FAILED;
3915         }
3916
3917       /* Read up to 4 arguments, but don't do the end of item check afterwards,
3918       because there may be a string for expansion on failure. */
3919
3920       switch(read_subs(sub_arg, 4, 2, &s, skipping, FALSE, US"readsocket"))
3921         {
3922         case 1: goto EXPAND_FAILED_CURLY;
3923         case 2:                             /* Won't occur: no end check */
3924         case 3: goto EXPAND_FAILED;
3925         }
3926
3927       /* Sort out timeout, if given */
3928
3929       if (sub_arg[2] != NULL)
3930         {
3931         timeout = readconf_readtime(sub_arg[2], 0, FALSE);
3932         if (timeout < 0)
3933           {
3934           expand_string_message = string_sprintf("bad time value %s",
3935             sub_arg[2]);
3936           goto EXPAND_FAILED;
3937           }
3938         }
3939       else sub_arg[3] = NULL;                     /* No eol if no timeout */
3940
3941       /* If skipping, we don't actually do anything. Otherwise, arrange to
3942       connect to either an IP or a Unix socket. */
3943
3944       if (!skipping)
3945         {
3946         /* Handle an IP (internet) domain */
3947
3948         if (Ustrncmp(sub_arg[0], "inet:", 5) == 0)
3949           {
3950           BOOL connected = FALSE;
3951           int namelen, port;
3952           host_item shost;
3953           host_item *h;
3954           uschar *server_name = sub_arg[0] + 5;
3955           uschar *port_name = Ustrrchr(server_name, ':');
3956
3957           /* Sort out the port */
3958
3959           if (port_name == NULL)
3960             {
3961             expand_string_message =
3962               string_sprintf("missing port for readsocket %s", sub_arg[0]);
3963             goto EXPAND_FAILED;
3964             }
3965           *port_name++ = 0;           /* Terminate server name */
3966
3967           if (isdigit(*port_name))
3968             {
3969             uschar *end;
3970             port = Ustrtol(port_name, &end, 0);
3971             if (end != port_name + Ustrlen(port_name))
3972               {
3973               expand_string_message =
3974                 string_sprintf("invalid port number %s", port_name);
3975               goto EXPAND_FAILED;
3976               }
3977             }
3978           else
3979             {
3980             struct servent *service_info = getservbyname(CS port_name, "tcp");
3981             if (service_info == NULL)
3982               {
3983               expand_string_message = string_sprintf("unknown port \"%s\"",
3984                 port_name);
3985               goto EXPAND_FAILED;
3986               }
3987             port = ntohs(service_info->s_port);
3988             }
3989
3990           /* Sort out the server. */
3991
3992           shost.next = NULL;
3993           shost.address = NULL;
3994           shost.port = port;
3995           shost.mx = -1;
3996
3997           namelen = Ustrlen(server_name);
3998
3999           /* Anything enclosed in [] must be an IP address. */
4000
4001           if (server_name[0] == '[' &&
4002               server_name[namelen - 1] == ']')
4003             {
4004             server_name[namelen - 1] = 0;
4005             server_name++;
4006             if (string_is_ip_address(server_name, NULL) == 0)
4007               {
4008               expand_string_message =
4009                 string_sprintf("malformed IP address \"%s\"", server_name);
4010               goto EXPAND_FAILED;
4011               }
4012             shost.name = shost.address = server_name;
4013             }
4014
4015           /* Otherwise check for an unadorned IP address */
4016
4017           else if (string_is_ip_address(server_name, NULL) != 0)
4018             shost.name = shost.address = server_name;
4019
4020           /* Otherwise lookup IP address(es) from the name */
4021
4022           else
4023             {
4024             shost.name = server_name;
4025             if (host_find_byname(&shost, NULL, HOST_FIND_QUALIFY_SINGLE, NULL,
4026                 FALSE) != HOST_FOUND)
4027               {
4028               expand_string_message =
4029                 string_sprintf("no IP address found for host %s", shost.name);
4030               goto EXPAND_FAILED;
4031               }
4032             }
4033
4034           /* Try to connect to the server - test each IP till one works */
4035
4036           for (h = &shost; h != NULL; h = h->next)
4037             {
4038             int af = (Ustrchr(h->address, ':') != 0)? AF_INET6 : AF_INET;
4039             if ((fd = ip_socket(SOCK_STREAM, af)) == -1)
4040               {
4041               expand_string_message = string_sprintf("failed to create socket: "
4042                 "%s", strerror(errno));
4043               goto SOCK_FAIL;
4044               }
4045
4046             if (ip_connect(fd, af, h->address, port, timeout) == 0)
4047               {
4048               connected = TRUE;
4049               break;
4050               }
4051             }
4052
4053           if (!connected)
4054             {
4055             expand_string_message = string_sprintf("failed to connect to "
4056               "socket %s: couldn't connect to any host", sub_arg[0],
4057               strerror(errno));
4058             goto SOCK_FAIL;
4059             }
4060           }
4061
4062         /* Handle a Unix domain socket */
4063
4064         else
4065           {
4066           int rc;
4067           if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
4068             {
4069             expand_string_message = string_sprintf("failed to create socket: %s",
4070               strerror(errno));
4071             goto SOCK_FAIL;
4072             }
4073
4074           sockun.sun_family = AF_UNIX;
4075           sprintf(sockun.sun_path, "%.*s", (int)(sizeof(sockun.sun_path)-1),
4076             sub_arg[0]);
4077
4078           sigalrm_seen = FALSE;
4079           alarm(timeout);
4080           rc = connect(fd, (struct sockaddr *)(&sockun), sizeof(sockun));
4081           alarm(0);
4082           if (sigalrm_seen)
4083             {
4084             expand_string_message = US "socket connect timed out";
4085             goto SOCK_FAIL;
4086             }
4087           if (rc < 0)
4088             {
4089             expand_string_message = string_sprintf("failed to connect to socket "
4090               "%s: %s", sub_arg[0], strerror(errno));
4091             goto SOCK_FAIL;
4092             }
4093           }
4094
4095         DEBUG(D_expand) debug_printf("connected to socket %s\n", sub_arg[0]);
4096
4097         /* Write the request string, if not empty */
4098
4099         if (sub_arg[1][0] != 0)
4100           {
4101           int len = Ustrlen(sub_arg[1]);
4102           DEBUG(D_expand) debug_printf("writing \"%s\" to socket\n",
4103             sub_arg[1]);
4104           if (write(fd, sub_arg[1], len) != len)
4105             {
4106             expand_string_message = string_sprintf("request write to socket "
4107               "failed: %s", strerror(errno));
4108             goto SOCK_FAIL;
4109             }
4110           }
4111
4112         /* Shut down the sending side of the socket. This helps some servers to
4113         recognise that it is their turn to do some work. Just in case some
4114         system doesn't have this function, make it conditional. */
4115
4116         #ifdef SHUT_WR
4117         shutdown(fd, SHUT_WR);
4118         #endif
4119
4120         /* Now we need to read from the socket, under a timeout. The function
4121         that reads a file can be used. */
4122
4123         f = fdopen(fd, "rb");
4124         sigalrm_seen = FALSE;
4125         alarm(timeout);
4126         yield = cat_file(f, yield, &size, &ptr, sub_arg[3]);
4127         alarm(0);
4128         (void)fclose(f);
4129
4130         /* After a timeout, we restore the pointer in the result, that is,
4131         make sure we add nothing from the socket. */
4132
4133         if (sigalrm_seen)
4134           {
4135           ptr = save_ptr;
4136           expand_string_message = US "socket read timed out";
4137           goto SOCK_FAIL;
4138           }
4139         }
4140
4141       /* The whole thing has worked (or we were skipping). If there is a
4142       failure string following, we need to skip it. */
4143
4144       if (*s == '{')
4145         {
4146         if (expand_string_internal(s+1, TRUE, &s, TRUE) == NULL)
4147           goto EXPAND_FAILED;
4148         if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4149         while (isspace(*s)) s++;
4150         }
4151       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4152       continue;
4153
4154       /* Come here on failure to create socket, connect socket, write to the
4155       socket, or timeout on reading. If another substring follows, expand and
4156       use it. Otherwise, those conditions give expand errors. */
4157
4158       SOCK_FAIL:
4159       if (*s != '{') goto EXPAND_FAILED;
4160       DEBUG(D_any) debug_printf("%s\n", expand_string_message);
4161       arg = expand_string_internal(s+1, TRUE, &s, FALSE);
4162       if (arg == NULL) goto EXPAND_FAILED;
4163       yield = string_cat(yield, &size, &ptr, arg, Ustrlen(arg));
4164       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4165       while (isspace(*s)) s++;
4166       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4167       continue;
4168       }
4169
4170     /* Handle "run" to execute a program. */
4171
4172     case EITEM_RUN:
4173       {
4174       FILE *f;
4175       uschar *arg;
4176       uschar **argv;
4177       pid_t pid;
4178       int fd_in, fd_out;
4179       int lsize = 0;
4180       int lptr = 0;
4181
4182       if ((expand_forbid & RDO_RUN) != 0)
4183         {
4184         expand_string_message = US"running a command is not permitted";
4185         goto EXPAND_FAILED;
4186         }
4187
4188       while (isspace(*s)) s++;
4189       if (*s != '{') goto EXPAND_FAILED_CURLY;
4190       arg = expand_string_internal(s+1, TRUE, &s, skipping);
4191       if (arg == NULL) goto EXPAND_FAILED;
4192       while (isspace(*s)) s++;
4193       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4194
4195       if (skipping)   /* Just pretend it worked when we're skipping */
4196         {
4197         runrc = 0;
4198         }
4199       else
4200         {
4201         if (!transport_set_up_command(&argv,    /* anchor for arg list */
4202             arg,                                /* raw command */
4203             FALSE,                              /* don't expand the arguments */
4204             0,                                  /* not relevant when... */
4205             NULL,                               /* no transporting address */
4206             US"${run} expansion",               /* for error messages */
4207             &expand_string_message))            /* where to put error message */
4208           {
4209           goto EXPAND_FAILED;
4210           }
4211
4212         /* Create the child process, making it a group leader. */
4213
4214         pid = child_open(argv, NULL, 0077, &fd_in, &fd_out, TRUE);
4215
4216         if (pid < 0)
4217           {
4218           expand_string_message =
4219             string_sprintf("couldn't create child process: %s", strerror(errno));
4220           goto EXPAND_FAILED;
4221           }
4222
4223         /* Nothing is written to the standard input. */
4224
4225         (void)close(fd_in);
4226
4227         /* Wait for the process to finish, applying the timeout, and inspect its
4228         return code for serious disasters. Simple non-zero returns are passed on.
4229         */
4230
4231         if ((runrc = child_close(pid, 60)) < 0)
4232           {
4233           if (runrc == -256)
4234             {
4235             expand_string_message = string_sprintf("command timed out");
4236             killpg(pid, SIGKILL);       /* Kill the whole process group */
4237             }
4238
4239           else if (runrc == -257)
4240             expand_string_message = string_sprintf("wait() failed: %s",
4241               strerror(errno));
4242
4243           else
4244             expand_string_message = string_sprintf("command killed by signal %d",
4245               -runrc);
4246
4247           goto EXPAND_FAILED;
4248           }
4249
4250         /* Read the pipe to get the command's output into $value (which is kept
4251         in lookup_value). */
4252
4253         f = fdopen(fd_out, "rb");
4254         lookup_value = NULL;
4255         lookup_value = cat_file(f, lookup_value, &lsize, &lptr, NULL);
4256         (void)fclose(f);
4257         }
4258
4259       /* Process the yes/no strings; $value may be useful in both cases */
4260
4261       switch(process_yesno(
4262                skipping,                     /* were previously skipping */
4263                runrc == 0,                   /* success/failure indicator */
4264                lookup_value,                 /* value to reset for string2 */
4265                &s,                           /* input pointer */
4266                &yield,                       /* output pointer */
4267                &size,                        /* output size */
4268                &ptr,                         /* output current point */
4269                US"run"))                     /* condition type */
4270         {
4271         case 1: goto EXPAND_FAILED;          /* when all is well, the */
4272         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
4273         }
4274
4275       continue;
4276       }
4277
4278     /* Handle character translation for "tr" */
4279
4280     case EITEM_TR:
4281       {
4282       int oldptr = ptr;
4283       int o2m;
4284       uschar *sub[3];
4285
4286       switch(read_subs(sub, 3, 3, &s, skipping, TRUE, US"tr"))
4287         {
4288         case 1: goto EXPAND_FAILED_CURLY;
4289         case 2:
4290         case 3: goto EXPAND_FAILED;
4291         }
4292
4293       yield = string_cat(yield, &size, &ptr, sub[0], Ustrlen(sub[0]));
4294       o2m = Ustrlen(sub[2]) - 1;
4295
4296       if (o2m >= 0) for (; oldptr < ptr; oldptr++)
4297         {
4298         uschar *m = Ustrrchr(sub[1], yield[oldptr]);
4299         if (m != NULL)
4300           {
4301           int o = m - sub[1];
4302           yield[oldptr] = sub[2][(o < o2m)? o : o2m];
4303           }
4304         }
4305
4306       continue;
4307       }
4308
4309     /* Handle "hash", "length", "nhash", and "substr" when they are given with
4310     expanded arguments. */
4311
4312     case EITEM_HASH:
4313     case EITEM_LENGTH:
4314     case EITEM_NHASH:
4315     case EITEM_SUBSTR:
4316       {
4317       int i;
4318       int len;
4319       uschar *ret;
4320       int val[2] = { 0, -1 };
4321       uschar *sub[3];
4322
4323       /* "length" takes only 2 arguments whereas the others take 2 or 3.
4324       Ensure that sub[2] is set in the ${length case. */
4325
4326       sub[2] = NULL;
4327       switch(read_subs(sub, (item_type == EITEM_LENGTH)? 2:3, 2, &s, skipping,
4328              TRUE, name))
4329         {
4330         case 1: goto EXPAND_FAILED_CURLY;
4331         case 2:
4332         case 3: goto EXPAND_FAILED;
4333         }
4334
4335       /* Juggle the arguments if there are only two of them: always move the
4336       string to the last position and make ${length{n}{str}} equivalent to
4337       ${substr{0}{n}{str}}. See the defaults for val[] above. */
4338
4339       if (sub[2] == NULL)
4340         {
4341         sub[2] = sub[1];
4342         sub[1] = NULL;
4343         if (item_type == EITEM_LENGTH)
4344           {
4345           sub[1] = sub[0];
4346           sub[0] = NULL;
4347           }
4348         }
4349
4350       for (i = 0; i < 2; i++)
4351         {
4352         if (sub[i] == NULL) continue;
4353         val[i] = (int)Ustrtol(sub[i], &ret, 10);
4354         if (*ret != 0 || (i != 0 && val[i] < 0))
4355           {
4356           expand_string_message = string_sprintf("\"%s\" is not a%s number "
4357             "(in \"%s\" expansion)", sub[i], (i != 0)? " positive" : "", name);
4358           goto EXPAND_FAILED;
4359           }
4360         }
4361
4362       ret =
4363         (item_type == EITEM_HASH)?
4364           compute_hash(sub[2], val[0], val[1], &len) :
4365         (item_type == EITEM_NHASH)?
4366           compute_nhash(sub[2], val[0], val[1], &len) :
4367           extract_substr(sub[2], val[0], val[1], &len);
4368
4369       if (ret == NULL) goto EXPAND_FAILED;
4370       yield = string_cat(yield, &size, &ptr, ret, len);
4371       continue;
4372       }
4373
4374     /* Handle HMAC computation: ${hmac{<algorithm>}{<secret>}{<text>}}
4375     This code originally contributed by Steve Haslam. It currently supports
4376     the use of MD5 and SHA-1 hashes.
4377
4378     We need some workspace that is large enough to handle all the supported
4379     hash types. Use macros to set the sizes rather than be too elaborate. */
4380
4381     #define MAX_HASHLEN      20
4382     #define MAX_HASHBLOCKLEN 64
4383
4384     case EITEM_HMAC:
4385       {
4386       uschar *sub[3];
4387       md5 md5_base;
4388       sha1 sha1_base;
4389       void *use_base;
4390       int type, i;
4391       int hashlen;      /* Number of octets for the hash algorithm's output */
4392       int hashblocklen; /* Number of octets the hash algorithm processes */
4393       uschar *keyptr, *p;
4394       unsigned int keylen;
4395
4396       uschar keyhash[MAX_HASHLEN];
4397       uschar innerhash[MAX_HASHLEN];
4398       uschar finalhash[MAX_HASHLEN];
4399       uschar finalhash_hex[2*MAX_HASHLEN];
4400       uschar innerkey[MAX_HASHBLOCKLEN];
4401       uschar outerkey[MAX_HASHBLOCKLEN];
4402
4403       switch (read_subs(sub, 3, 3, &s, skipping, TRUE, name))
4404         {
4405         case 1: goto EXPAND_FAILED_CURLY;
4406         case 2:
4407         case 3: goto EXPAND_FAILED;
4408         }
4409
4410       if (Ustrcmp(sub[0], "md5") == 0)
4411         {
4412         type = HMAC_MD5;
4413         use_base = &md5_base;
4414         hashlen = 16;
4415         hashblocklen = 64;
4416         }
4417       else if (Ustrcmp(sub[0], "sha1") == 0)
4418         {
4419         type = HMAC_SHA1;
4420         use_base = &sha1_base;
4421         hashlen = 20;
4422         hashblocklen = 64;
4423         }
4424       else
4425         {
4426         expand_string_message =
4427           string_sprintf("hmac algorithm \"%s\" is not recognised", sub[0]);
4428         goto EXPAND_FAILED;
4429         }
4430
4431       keyptr = sub[1];
4432       keylen = Ustrlen(keyptr);
4433
4434       /* If the key is longer than the hash block length, then hash the key
4435       first */
4436
4437       if (keylen > hashblocklen)
4438         {
4439         chash_start(type, use_base);
4440         chash_end(type, use_base, keyptr, keylen, keyhash);
4441         keyptr = keyhash;
4442         keylen = hashlen;
4443         }
4444
4445       /* Now make the inner and outer key values */
4446
4447       memset(innerkey, 0x36, hashblocklen);
4448       memset(outerkey, 0x5c, hashblocklen);
4449
4450       for (i = 0; i < keylen; i++)
4451         {
4452         innerkey[i] ^= keyptr[i];
4453         outerkey[i] ^= keyptr[i];
4454         }
4455
4456       /* Now do the hashes */
4457
4458       chash_start(type, use_base);
4459       chash_mid(type, use_base, innerkey);
4460       chash_end(type, use_base, sub[2], Ustrlen(sub[2]), innerhash);
4461
4462       chash_start(type, use_base);
4463       chash_mid(type, use_base, outerkey);
4464       chash_end(type, use_base, innerhash, hashlen, finalhash);
4465
4466       /* Encode the final hash as a hex string */
4467
4468       p = finalhash_hex;
4469       for (i = 0; i < hashlen; i++)
4470         {
4471         *p++ = hex_digits[(finalhash[i] & 0xf0) >> 4];
4472         *p++ = hex_digits[finalhash[i] & 0x0f];
4473         }
4474
4475       DEBUG(D_any) debug_printf("HMAC[%s](%.*s,%.*s)=%.*s\n", sub[0],
4476         (int)keylen, keyptr, Ustrlen(sub[2]), sub[2], hashlen*2, finalhash_hex);
4477
4478       yield = string_cat(yield, &size, &ptr, finalhash_hex, hashlen*2);
4479       }
4480
4481     continue;
4482
4483     /* Handle global substitution for "sg" - like Perl's s/xxx/yyy/g operator.
4484     We have to save the numerical variables and restore them afterwards. */
4485
4486     case EITEM_SG:
4487       {
4488       const pcre *re;
4489       int moffset, moffsetextra, slen;
4490       int roffset;
4491       int emptyopt;
4492       const uschar *rerror;
4493       uschar *subject;
4494       uschar *sub[3];
4495       int save_expand_nmax =
4496         save_expand_strings(save_expand_nstring, save_expand_nlength);
4497
4498       switch(read_subs(sub, 3, 3, &s, skipping, TRUE, US"sg"))
4499         {
4500         case 1: goto EXPAND_FAILED_CURLY;
4501         case 2:
4502         case 3: goto EXPAND_FAILED;
4503         }
4504
4505       /* Compile the regular expression */
4506
4507       re = pcre_compile(CS sub[1], PCRE_COPT, (const char **)&rerror, &roffset,
4508         NULL);
4509
4510       if (re == NULL)
4511         {
4512         expand_string_message = string_sprintf("regular expression error in "
4513           "\"%s\": %s at offset %d", sub[1], rerror, roffset);
4514         goto EXPAND_FAILED;
4515         }
4516
4517       /* Now run a loop to do the substitutions as often as necessary. It ends
4518       when there are no more matches. Take care over matches of the null string;
4519       do the same thing as Perl does. */
4520
4521       subject = sub[0];
4522       slen = Ustrlen(sub[0]);
4523       moffset = moffsetextra = 0;
4524       emptyopt = 0;
4525
4526       for (;;)
4527         {
4528         int ovector[3*(EXPAND_MAXN+1)];
4529         int n = pcre_exec(re, NULL, CS subject, slen, moffset + moffsetextra,
4530           PCRE_EOPT | emptyopt, ovector, sizeof(ovector)/sizeof(int));
4531         int nn;
4532         uschar *insert;
4533
4534         /* No match - if we previously set PCRE_NOTEMPTY after a null match, this
4535         is not necessarily the end. We want to repeat the match from one
4536         character further along, but leaving the basic offset the same (for
4537         copying below). We can't be at the end of the string - that was checked
4538         before setting PCRE_NOTEMPTY. If PCRE_NOTEMPTY is not set, we are
4539         finished; copy the remaining string and end the loop. */
4540
4541         if (n < 0)
4542           {
4543           if (emptyopt != 0)
4544             {
4545             moffsetextra = 1;
4546             emptyopt = 0;
4547             continue;
4548             }
4549           yield = string_cat(yield, &size, &ptr, subject+moffset, slen-moffset);
4550           break;
4551           }
4552
4553         /* Match - set up for expanding the replacement. */
4554
4555         if (n == 0) n = EXPAND_MAXN + 1;
4556         expand_nmax = 0;
4557         for (nn = 0; nn < n*2; nn += 2)
4558           {
4559           expand_nstring[expand_nmax] = subject + ovector[nn];
4560           expand_nlength[expand_nmax++] = ovector[nn+1] - ovector[nn];
4561           }
4562         expand_nmax--;
4563
4564         /* Copy the characters before the match, plus the expanded insertion. */
4565
4566         yield = string_cat(yield, &size, &ptr, subject + moffset,
4567           ovector[0] - moffset);
4568         insert = expand_string(sub[2]);
4569         if (insert == NULL) goto EXPAND_FAILED;
4570         yield = string_cat(yield, &size, &ptr, insert, Ustrlen(insert));
4571
4572         moffset = ovector[1];
4573         moffsetextra = 0;
4574         emptyopt = 0;
4575
4576         /* If we have matched an empty string, first check to see if we are at
4577         the end of the subject. If so, the loop is over. Otherwise, mimic
4578         what Perl's /g options does. This turns out to be rather cunning. First
4579         we set PCRE_NOTEMPTY and PCRE_ANCHORED and try the match a non-empty
4580         string at the same point. If this fails (picked up above) we advance to
4581         the next character. */
4582
4583         if (ovector[0] == ovector[1])
4584           {
4585           if (ovector[0] == slen) break;
4586           emptyopt = PCRE_NOTEMPTY | PCRE_ANCHORED;
4587           }
4588         }
4589
4590       /* All done - restore numerical variables. */
4591
4592       restore_expand_strings(save_expand_nmax, save_expand_nstring,
4593         save_expand_nlength);
4594       continue;
4595       }
4596
4597     /* Handle keyed and numbered substring extraction. If the first argument
4598     consists entirely of digits, then a numerical extraction is assumed. */
4599
4600     case EITEM_EXTRACT:
4601       {
4602       int i;
4603       int j = 2;
4604       int field_number = 1;
4605       BOOL field_number_set = FALSE;
4606       uschar *save_lookup_value = lookup_value;
4607       uschar *sub[3];
4608       int save_expand_nmax =
4609         save_expand_strings(save_expand_nstring, save_expand_nlength);
4610
4611       /* Read the arguments */
4612
4613       for (i = 0; i < j; i++)
4614         {
4615         while (isspace(*s)) s++;
4616         if (*s == '{')
4617           {
4618           sub[i] = expand_string_internal(s+1, TRUE, &s, skipping);
4619           if (sub[i] == NULL) goto EXPAND_FAILED;
4620           if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4621
4622           /* After removal of leading and trailing white space, the first
4623           argument must not be empty; if it consists entirely of digits
4624           (optionally preceded by a minus sign), this is a numerical
4625           extraction, and we expect 3 arguments. */
4626
4627           if (i == 0)
4628             {
4629             int len;
4630             int x = 0;
4631             uschar *p = sub[0];
4632
4633             while (isspace(*p)) p++;
4634             sub[0] = p;
4635
4636             len = Ustrlen(p);
4637             while (len > 0 && isspace(p[len-1])) len--;
4638             p[len] = 0;
4639
4640             if (*p == 0)
4641               {
4642               expand_string_message = US"first argument of \"extract\" must "
4643                 "not be empty";
4644               goto EXPAND_FAILED;
4645               }
4646
4647             if (*p == '-')
4648               {
4649               field_number = -1;
4650               p++;
4651               }
4652             while (*p != 0 && isdigit(*p)) x = x * 10 + *p++ - '0';
4653             if (*p == 0)
4654               {
4655               field_number *= x;
4656               j = 3;               /* Need 3 args */
4657               field_number_set = TRUE;
4658               }
4659             }
4660           }
4661         else goto EXPAND_FAILED_CURLY;
4662         }
4663
4664       /* Extract either the numbered or the keyed substring into $value. If
4665       skipping, just pretend the extraction failed. */
4666
4667       lookup_value = skipping? NULL : field_number_set?
4668         expand_gettokened(field_number, sub[1], sub[2]) :
4669         expand_getkeyed(sub[0], sub[1]);
4670
4671       /* If no string follows, $value gets substituted; otherwise there can
4672       be yes/no strings, as for lookup or if. */
4673
4674       switch(process_yesno(
4675                skipping,                     /* were previously skipping */
4676                lookup_value != NULL,         /* success/failure indicator */
4677                save_lookup_value,            /* value to reset for string2 */
4678                &s,                           /* input pointer */
4679                &yield,                       /* output pointer */
4680                &size,                        /* output size */
4681                &ptr,                         /* output current point */
4682                US"extract"))                 /* condition type */
4683         {
4684         case 1: goto EXPAND_FAILED;          /* when all is well, the */
4685         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
4686         }
4687
4688       /* All done - restore numerical variables. */
4689
4690       restore_expand_strings(save_expand_nmax, save_expand_nstring,
4691         save_expand_nlength);
4692
4693       continue;
4694       }
4695
4696
4697     /* Handle list operations */
4698
4699     case EITEM_FILTER:
4700     case EITEM_MAP:
4701     case EITEM_REDUCE:
4702       {
4703       int sep = 0;
4704       int save_ptr = ptr;
4705       uschar outsep[2] = { '\0', '\0' };
4706       uschar *list, *expr, *temp;
4707       uschar *save_iterate_item = iterate_item;
4708       uschar *save_lookup_value = lookup_value;
4709
4710       while (isspace(*s)) s++;
4711       if (*s++ != '{') goto EXPAND_FAILED_CURLY;
4712
4713       list = expand_string_internal(s, TRUE, &s, skipping);
4714       if (list == NULL) goto EXPAND_FAILED;
4715       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4716
4717       if (item_type == EITEM_REDUCE)
4718         {
4719         while (isspace(*s)) s++;
4720         if (*s++ != '{') goto EXPAND_FAILED_CURLY;
4721         temp = expand_string_internal(s, TRUE, &s, skipping);
4722         if (temp == NULL) goto EXPAND_FAILED;
4723         lookup_value = temp;
4724         if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4725         }
4726
4727       while (isspace(*s)) s++;
4728       if (*s++ != '{') goto EXPAND_FAILED_CURLY;
4729
4730       expr = s;
4731
4732       /* For EITEM_FILTER, call eval_condition once, with result discarded (as
4733       if scanning a "false" part). This allows us to find the end of the
4734       condition, because if the list is empty, we won't actually evaluate the
4735       condition for real. For EITEM_MAP and EITEM_REDUCE, do the same, using
4736       the normal internal expansion function. */
4737
4738       if (item_type == EITEM_FILTER)
4739         {
4740         temp = eval_condition(expr, NULL);
4741         if (temp != NULL) s = temp;
4742         }
4743       else
4744         {
4745         temp = expand_string_internal(s, TRUE, &s, TRUE);
4746         }
4747
4748       if (temp == NULL)
4749         {
4750         expand_string_message = string_sprintf("%s inside \"%s\" item",
4751           expand_string_message, name);
4752         goto EXPAND_FAILED;
4753         }
4754
4755       while (isspace(*s)) s++;
4756       if (*s++ != '}')
4757         {
4758         expand_string_message = string_sprintf("missing } at end of condition "
4759           "or expression inside \"%s\"", name);
4760         goto EXPAND_FAILED;
4761         }
4762
4763       while (isspace(*s)) s++;
4764       if (*s++ != '}')
4765         {
4766         expand_string_message = string_sprintf("missing } at end of \"%s\"",
4767           name);
4768         goto EXPAND_FAILED;
4769         }
4770
4771       /* If we are skipping, we can now just move on to the next item. When
4772       processing for real, we perform the iteration. */
4773
4774       if (skipping) continue;
4775       while ((iterate_item = string_nextinlist(&list, &sep, NULL, 0)) != NULL)
4776         {
4777         *outsep = (uschar)sep;      /* Separator as a string */
4778
4779         DEBUG(D_expand) debug_printf("%s: $item = \"%s\"\n", name, iterate_item);
4780
4781         if (item_type == EITEM_FILTER)
4782           {
4783           BOOL condresult;
4784           if (eval_condition(expr, &condresult) == NULL)
4785             {
4786             iterate_item = save_iterate_item;
4787             lookup_value = save_lookup_value;
4788             expand_string_message = string_sprintf("%s inside \"%s\" condition",
4789               expand_string_message, name);
4790             goto EXPAND_FAILED;
4791             }
4792           DEBUG(D_expand) debug_printf("%s: condition is %s\n", name,
4793             condresult? "true":"false");
4794           if (condresult)
4795             temp = iterate_item;    /* TRUE => include this item */
4796           else
4797             continue;               /* FALSE => skip this item */
4798           }
4799
4800         /* EITEM_MAP and EITEM_REDUCE */
4801
4802         else
4803           {
4804           temp = expand_string_internal(expr, TRUE, NULL, skipping);
4805           if (temp == NULL)
4806             {
4807             iterate_item = save_iterate_item;
4808             expand_string_message = string_sprintf("%s inside \"%s\" item",
4809               expand_string_message, name);
4810             goto EXPAND_FAILED;
4811             }
4812           if (item_type == EITEM_REDUCE)
4813             {
4814             lookup_value = temp;      /* Update the value of $value */
4815             continue;                 /* and continue the iteration */
4816             }
4817           }
4818
4819         /* We reach here for FILTER if the condition is true, always for MAP,
4820         and never for REDUCE. The value in "temp" is to be added to the output
4821         list that is being created, ensuring that any occurrences of the
4822         separator character are doubled. Unless we are dealing with the first
4823         item of the output list, add in a space if the new item begins with the
4824         separator character, or is an empty string. */
4825
4826         if (ptr != save_ptr && (temp[0] == *outsep || temp[0] == 0))
4827           yield = string_cat(yield, &size, &ptr, US" ", 1);
4828
4829         /* Add the string in "temp" to the output list that we are building,
4830         This is done in chunks by searching for the separator character. */
4831
4832         for (;;)
4833           {
4834           size_t seglen = Ustrcspn(temp, outsep);
4835             yield = string_cat(yield, &size, &ptr, temp, seglen + 1);
4836
4837           /* If we got to the end of the string we output one character
4838           too many; backup and end the loop. Otherwise arrange to double the
4839           separator. */
4840
4841           if (temp[seglen] == '\0') { ptr--; break; }
4842           yield = string_cat(yield, &size, &ptr, outsep, 1);
4843           temp += seglen + 1;
4844           }
4845
4846         /* Output a separator after the string: we will remove the redundant
4847         final one at the end. */
4848
4849         yield = string_cat(yield, &size, &ptr, outsep, 1);
4850         }   /* End of iteration over the list loop */
4851
4852       /* REDUCE has generated no output above: output the final value of
4853       $value. */
4854
4855       if (item_type == EITEM_REDUCE)
4856         {
4857         yield = string_cat(yield, &size, &ptr, lookup_value,
4858           Ustrlen(lookup_value));
4859         lookup_value = save_lookup_value;  /* Restore $value */
4860         }
4861
4862       /* FILTER and MAP generate lists: if they have generated anything, remove
4863       the redundant final separator. Even though an empty item at the end of a
4864       list does not count, this is tidier. */
4865
4866       else if (ptr != save_ptr) ptr--;
4867
4868       /* Restore preserved $item */
4869
4870       iterate_item = save_iterate_item;
4871       continue;
4872       }
4873
4874
4875     /* If ${dlfunc support is configured, handle calling dynamically-loaded
4876     functions, unless locked out at this time. Syntax is ${dlfunc{file}{func}}
4877     or ${dlfunc{file}{func}{arg}} or ${dlfunc{file}{func}{arg1}{arg2}} or up to
4878     a maximum of EXPAND_DLFUNC_MAX_ARGS arguments (defined below). */
4879
4880     #define EXPAND_DLFUNC_MAX_ARGS 8
4881
4882     case EITEM_DLFUNC:
4883     #ifndef EXPAND_DLFUNC
4884     expand_string_message = US"\"${dlfunc\" encountered, but this facility "
4885       "is not included in this binary";
4886     goto EXPAND_FAILED;
4887
4888     #else   /* EXPAND_DLFUNC */
4889       {
4890       tree_node *t;
4891       exim_dlfunc_t *func;
4892       uschar *result;
4893       int status, argc;
4894       uschar *argv[EXPAND_DLFUNC_MAX_ARGS + 3];
4895
4896       if ((expand_forbid & RDO_DLFUNC) != 0)
4897         {
4898         expand_string_message =
4899           US"dynamically-loaded functions are not permitted";
4900         goto EXPAND_FAILED;
4901         }
4902
4903       switch(read_subs(argv, EXPAND_DLFUNC_MAX_ARGS + 2, 2, &s, skipping,
4904            TRUE, US"dlfunc"))
4905         {
4906         case 1: goto EXPAND_FAILED_CURLY;
4907         case 2:
4908         case 3: goto EXPAND_FAILED;
4909         }
4910
4911       /* If skipping, we don't actually do anything */
4912
4913       if (skipping) continue;
4914
4915       /* Look up the dynamically loaded object handle in the tree. If it isn't
4916       found, dlopen() the file and put the handle in the tree for next time. */
4917
4918       t = tree_search(dlobj_anchor, argv[0]);
4919       if (t == NULL)
4920         {
4921         void *handle = dlopen(CS argv[0], RTLD_LAZY);
4922         if (handle == NULL)
4923           {
4924           expand_string_message = string_sprintf("dlopen \"%s\" failed: %s",
4925             argv[0], dlerror());
4926           log_write(0, LOG_MAIN|LOG_PANIC, "%s", expand_string_message);
4927           goto EXPAND_FAILED;
4928           }
4929         t = store_get_perm(sizeof(tree_node) + Ustrlen(argv[0]));
4930         Ustrcpy(t->name, argv[0]);
4931         t->data.ptr = handle;
4932         (void)tree_insertnode(&dlobj_anchor, t);
4933         }
4934
4935       /* Having obtained the dynamically loaded object handle, look up the
4936       function pointer. */
4937
4938       func = (exim_dlfunc_t *)dlsym(t->data.ptr, CS argv[1]);
4939       if (func == NULL)
4940         {
4941         expand_string_message = string_sprintf("dlsym \"%s\" in \"%s\" failed: "
4942           "%s", argv[1], argv[0], dlerror());
4943         log_write(0, LOG_MAIN|LOG_PANIC, "%s", expand_string_message);
4944         goto EXPAND_FAILED;
4945         }
4946
4947       /* Call the function and work out what to do with the result. If it
4948       returns OK, we have a replacement string; if it returns DEFER then
4949       expansion has failed in a non-forced manner; if it returns FAIL then
4950       failure was forced; if it returns ERROR or any other value there's a
4951       problem, so panic slightly. */
4952
4953       result = NULL;
4954       for (argc = 0; argv[argc] != NULL; argc++);
4955       status = func(&result, argc - 2, &argv[2]);
4956       if(status == OK)
4957         {
4958         if (result == NULL) result = US"";
4959         yield = string_cat(yield, &size, &ptr, result, Ustrlen(result));
4960         continue;
4961         }
4962       else
4963         {
4964         expand_string_message = result == NULL ? US"(no message)" : result;
4965         if(status == FAIL_FORCED) expand_string_forcedfail = TRUE;
4966           else if(status != FAIL)
4967             log_write(0, LOG_MAIN|LOG_PANIC, "dlfunc{%s}{%s} failed (%d): %s",
4968               argv[0], argv[1], status, expand_string_message);
4969         goto EXPAND_FAILED;
4970         }
4971       }
4972     #endif /* EXPAND_DLFUNC */
4973     }
4974
4975   /* Control reaches here if the name is not recognized as one of the more
4976   complicated expansion items. Check for the "operator" syntax (name terminated
4977   by a colon). Some of the operators have arguments, separated by _ from the
4978   name. */
4979
4980   if (*s == ':')
4981     {
4982     int c;
4983     uschar *arg = NULL;
4984     uschar *sub = expand_string_internal(s+1, TRUE, &s, skipping);
4985     if (sub == NULL) goto EXPAND_FAILED;
4986     s++;
4987
4988     /* Owing to an historical mis-design, an underscore may be part of the
4989     operator name, or it may introduce arguments.  We therefore first scan the
4990     table of names that contain underscores. If there is no match, we cut off
4991     the arguments and then scan the main table. */
4992
4993     c = chop_match(name, op_table_underscore,
4994       sizeof(op_table_underscore)/sizeof(uschar *));
4995
4996     if (c < 0)
4997       {
4998       arg = Ustrchr(name, '_');
4999       if (arg != NULL) *arg = 0;
5000       c = chop_match(name, op_table_main,
5001         sizeof(op_table_main)/sizeof(uschar *));
5002       if (c >= 0) c += sizeof(op_table_underscore)/sizeof(uschar *);
5003       if (arg != NULL) *arg++ = '_';   /* Put back for error messages */
5004       }
5005
5006     /* If we are skipping, we don't need to perform the operation at all.
5007     This matters for operations like "mask", because the data may not be
5008     in the correct format when skipping. For example, the expression may test
5009     for the existence of $sender_host_address before trying to mask it. For
5010     other operations, doing them may not fail, but it is a waste of time. */
5011
5012     if (skipping && c >= 0) continue;
5013
5014     /* Otherwise, switch on the operator type */
5015
5016     switch(c)
5017       {
5018       case EOP_BASE62:
5019         {
5020         uschar *t;
5021         unsigned long int n = Ustrtoul(sub, &t, 10);
5022         if (*t != 0)
5023           {
5024           expand_string_message = string_sprintf("argument for base62 "
5025             "operator is \"%s\", which is not a decimal number", sub);
5026           goto EXPAND_FAILED;
5027           }
5028         t = string_base62(n);
5029         yield = string_cat(yield, &size, &ptr, t, Ustrlen(t));
5030         continue;
5031         }
5032
5033       /* Note that for Darwin and Cygwin, BASE_62 actually has the value 36 */
5034
5035       case EOP_BASE62D:
5036         {
5037         uschar buf[16];
5038         uschar *tt = sub;
5039         unsigned long int n = 0;
5040         while (*tt != 0)
5041           {
5042           uschar *t = Ustrchr(base62_chars, *tt++);
5043           if (t == NULL)
5044             {
5045             expand_string_message = string_sprintf("argument for base62d "
5046               "operator is \"%s\", which is not a base %d number", sub,
5047               BASE_62);
5048             goto EXPAND_FAILED;
5049             }
5050           n = n * BASE_62 + (t - base62_chars);
5051           }
5052         (void)sprintf(CS buf, "%ld", n);
5053         yield = string_cat(yield, &size, &ptr, buf, Ustrlen(buf));
5054         continue;
5055         }
5056
5057       case EOP_EXPAND:
5058         {
5059         uschar *expanded = expand_string_internal(sub, FALSE, NULL, skipping);
5060         if (expanded == NULL)
5061           {
5062           expand_string_message =
5063             string_sprintf("internal expansion of \"%s\" failed: %s", sub,
5064               expand_string_message);
5065           goto EXPAND_FAILED;
5066           }
5067         yield = string_cat(yield, &size, &ptr, expanded, Ustrlen(expanded));
5068         continue;
5069         }
5070
5071       case EOP_LC:
5072         {
5073         int count = 0;
5074         uschar *t = sub - 1;
5075         while (*(++t) != 0) { *t = tolower(*t); count++; }
5076         yield = string_cat(yield, &size, &ptr, sub, count);
5077         continue;
5078         }
5079
5080       case EOP_UC:
5081         {
5082         int count = 0;
5083         uschar *t = sub - 1;
5084         while (*(++t) != 0) { *t = toupper(*t); count++; }
5085         yield = string_cat(yield, &size, &ptr, sub, count);
5086         continue;
5087         }
5088
5089       case EOP_MD5:
5090         {
5091         md5 base;
5092         uschar digest[16];
5093         int j;
5094         char st[33];
5095         md5_start(&base);
5096         md5_end(&base, sub, Ustrlen(sub), digest);
5097         for(j = 0; j < 16; j++) sprintf(st+2*j, "%02x", digest[j]);
5098         yield = string_cat(yield, &size, &ptr, US st, (int)strlen(st));
5099         continue;
5100         }
5101
5102       case EOP_SHA1:
5103         {
5104         sha1 base;
5105         uschar digest[20];
5106         int j;
5107         char st[41];
5108         sha1_start(&base);
5109         sha1_end(&base, sub, Ustrlen(sub), digest);
5110         for(j = 0; j < 20; j++) sprintf(st+2*j, "%02X", digest[j]);
5111         yield = string_cat(yield, &size, &ptr, US st, (int)strlen(st));
5112         continue;
5113         }
5114
5115       /* Convert hex encoding to base64 encoding */
5116
5117       case EOP_HEX2B64:
5118         {
5119         int c = 0;
5120         int b = -1;
5121         uschar *in = sub;
5122         uschar *out = sub;
5123         uschar *enc;
5124
5125         for (enc = sub; *enc != 0; enc++)
5126           {
5127           if (!isxdigit(*enc))
5128             {
5129             expand_string_message = string_sprintf("\"%s\" is not a hex "
5130               "string", sub);
5131             goto EXPAND_FAILED;
5132             }
5133           c++;
5134           }
5135
5136         if ((c & 1) != 0)
5137           {
5138           expand_string_message = string_sprintf("\"%s\" contains an odd "
5139             "number of characters", sub);
5140           goto EXPAND_FAILED;
5141           }
5142
5143         while ((c = *in++) != 0)
5144           {
5145           if (isdigit(c)) c -= '0';
5146           else c = toupper(c) - 'A' + 10;
5147           if (b == -1)
5148             {
5149             b = c << 4;
5150             }
5151           else
5152             {
5153             *out++ = b | c;
5154             b = -1;
5155             }
5156           }
5157
5158         enc = auth_b64encode(sub, out - sub);
5159         yield = string_cat(yield, &size, &ptr, enc, Ustrlen(enc));
5160         continue;
5161         }
5162
5163       /* mask applies a mask to an IP address; for example the result of
5164       ${mask:131.111.10.206/28} is 131.111.10.192/28. */
5165
5166       case EOP_MASK:
5167         {
5168         int count;
5169         uschar *endptr;
5170         int binary[4];
5171         int mask, maskoffset;
5172         int type = string_is_ip_address(sub, &maskoffset);
5173         uschar buffer[64];
5174
5175         if (type == 0)
5176           {
5177           expand_string_message = string_sprintf("\"%s\" is not an IP address",
5178            sub);
5179           goto EXPAND_FAILED;
5180           }
5181
5182         if (maskoffset == 0)
5183           {
5184           expand_string_message = string_sprintf("missing mask value in \"%s\"",
5185             sub);
5186           goto EXPAND_FAILED;
5187           }
5188
5189         mask = Ustrtol(sub + maskoffset + 1, &endptr, 10);
5190
5191         if (*endptr != 0 || mask < 0 || mask > ((type == 4)? 32 : 128))
5192           {
5193           expand_string_message = string_sprintf("mask value too big in \"%s\"",
5194             sub);
5195           goto EXPAND_FAILED;
5196           }
5197
5198         /* Convert the address to binary integer(s) and apply the mask */
5199
5200         sub[maskoffset] = 0;
5201         count = host_aton(sub, binary);
5202         host_mask(count, binary, mask);
5203
5204         /* Convert to masked textual format and add to output. */
5205
5206         yield = string_cat(yield, &size, &ptr, buffer,
5207           host_nmtoa(count, binary, mask, buffer, '.'));
5208         continue;
5209         }
5210
5211       case EOP_ADDRESS:
5212       case EOP_LOCAL_PART:
5213       case EOP_DOMAIN:
5214         {
5215         uschar *error;
5216         int start, end, domain;
5217         uschar *t = parse_extract_address(sub, &error, &start, &end, &domain,
5218           FALSE);
5219         if (t != NULL)
5220           {
5221           if (c != EOP_DOMAIN)
5222             {
5223             if (c == EOP_LOCAL_PART && domain != 0) end = start + domain - 1;
5224             yield = string_cat(yield, &size, &ptr, sub+start, end-start);
5225             }
5226           else if (domain != 0)
5227             {
5228             domain += start;
5229             yield = string_cat(yield, &size, &ptr, sub+domain, end-domain);
5230             }
5231           }
5232         continue;
5233         }
5234
5235       case EOP_ADDRESSES:
5236         {
5237         uschar outsep[2] = { ':', '\0' };
5238         uschar *address, *error;
5239         int save_ptr = ptr;
5240         int start, end, domain;  /* Not really used */
5241
5242         while (isspace(*sub)) sub++;
5243         if (*sub == '>') { *outsep = *++sub; ++sub; }
5244         parse_allow_group = TRUE;
5245
5246         for (;;)
5247           {
5248           uschar *p = parse_find_address_end(sub, FALSE);
5249           uschar saveend = *p;
5250           *p = '\0';
5251           address = parse_extract_address(sub, &error, &start, &end, &domain,
5252             FALSE);
5253           *p = saveend;
5254
5255           /* Add the address to the output list that we are building. This is
5256           done in chunks by searching for the separator character. At the
5257           start, unless we are dealing with the first address of the output
5258           list, add in a space if the new address begins with the separator
5259           character, or is an empty string. */
5260
5261           if (address != NULL)
5262             {
5263             if (ptr != save_ptr && address[0] == *outsep)
5264               yield = string_cat(yield, &size, &ptr, US" ", 1);
5265
5266             for (;;)
5267               {
5268               size_t seglen = Ustrcspn(address, outsep);
5269               yield = string_cat(yield, &size, &ptr, address, seglen + 1);
5270
5271               /* If we got to the end of the string we output one character
5272               too many. */
5273
5274               if (address[seglen] == '\0') { ptr--; break; }
5275               yield = string_cat(yield, &size, &ptr, outsep, 1);
5276               address += seglen + 1;
5277               }
5278
5279             /* Output a separator after the string: we will remove the
5280             redundant final one at the end. */
5281
5282             yield = string_cat(yield, &size, &ptr, outsep, 1);
5283             }
5284
5285           if (saveend == '\0') break;
5286           sub = p + 1;
5287           }
5288
5289         /* If we have generated anything, remove the redundant final
5290         separator. */
5291
5292         if (ptr != save_ptr) ptr--;
5293         parse_allow_group = FALSE;
5294         continue;
5295         }
5296
5297
5298       /* quote puts a string in quotes if it is empty or contains anything
5299       other than alphamerics, underscore, dot, or hyphen.
5300
5301       quote_local_part puts a string in quotes if RFC 2821/2822 requires it to
5302       be quoted in order to be a valid local part.
5303
5304       In both cases, newlines and carriage returns are converted into \n and \r
5305       respectively */
5306
5307       case EOP_QUOTE:
5308       case EOP_QUOTE_LOCAL_PART:
5309       if (arg == NULL)
5310         {
5311         BOOL needs_quote = (*sub == 0);      /* TRUE for empty string */
5312         uschar *t = sub - 1;
5313
5314         if (c == EOP_QUOTE)
5315           {
5316           while (!needs_quote && *(++t) != 0)
5317             needs_quote = !isalnum(*t) && !strchr("_-.", *t);
5318           }
5319         else  /* EOP_QUOTE_LOCAL_PART */
5320           {
5321           while (!needs_quote && *(++t) != 0)
5322             needs_quote = !isalnum(*t) &&
5323               strchr("!#$%&'*+-/=?^_`{|}~", *t) == NULL &&
5324               (*t != '.' || t == sub || t[1] == 0);
5325           }
5326
5327         if (needs_quote)
5328           {
5329           yield = string_cat(yield, &size, &ptr, US"\"", 1);
5330           t = sub - 1;
5331           while (*(++t) != 0)
5332             {
5333             if (*t == '\n')
5334               yield = string_cat(yield, &size, &ptr, US"\\n", 2);
5335             else if (*t == '\r')
5336               yield = string_cat(yield, &size, &ptr, US"\\r", 2);
5337             else
5338               {
5339               if (*t == '\\' || *t == '"')
5340                 yield = string_cat(yield, &size, &ptr, US"\\", 1);
5341               yield = string_cat(yield, &size, &ptr, t, 1);
5342               }
5343             }
5344           yield = string_cat(yield, &size, &ptr, US"\"", 1);
5345           }
5346         else yield = string_cat(yield, &size, &ptr, sub, Ustrlen(sub));
5347         continue;
5348         }
5349
5350       /* quote_lookuptype does lookup-specific quoting */
5351
5352       else
5353         {
5354         int n;
5355         uschar *opt = Ustrchr(arg, '_');
5356
5357         if (opt != NULL) *opt++ = 0;
5358
5359         n = search_findtype(arg, Ustrlen(arg));
5360         if (n < 0)
5361           {
5362           expand_string_message = search_error_message;
5363           goto EXPAND_FAILED;
5364           }
5365
5366         if (lookup_list[n].quote != NULL)
5367           sub = (lookup_list[n].quote)(sub, opt);
5368         else if (opt != NULL) sub = NULL;
5369
5370         if (sub == NULL)
5371           {
5372           expand_string_message = string_sprintf(
5373             "\"%s\" unrecognized after \"${quote_%s\"",
5374             opt, arg);
5375           goto EXPAND_FAILED;
5376           }
5377
5378         yield = string_cat(yield, &size, &ptr, sub, Ustrlen(sub));
5379         continue;
5380         }
5381
5382       /* rx quote sticks in \ before any non-alphameric character so that
5383       the insertion works in a regular expression. */
5384
5385       case EOP_RXQUOTE:
5386         {
5387         uschar *t = sub - 1;
5388         while (*(++t) != 0)
5389           {
5390           if (!isalnum(*t))
5391             yield = string_cat(yield, &size, &ptr, US"\\", 1);
5392           yield = string_cat(yield, &size, &ptr, t, 1);
5393           }
5394         continue;
5395         }
5396
5397       /* RFC 2047 encodes, assuming headers_charset (default ISO 8859-1) as
5398       prescribed by the RFC, if there are characters that need to be encoded */
5399
5400       case EOP_RFC2047:
5401         {
5402         uschar buffer[2048];
5403         uschar *string = parse_quote_2047(sub, Ustrlen(sub), headers_charset,
5404           buffer, sizeof(buffer), FALSE);
5405         yield = string_cat(yield, &size, &ptr, string, Ustrlen(string));
5406         continue;
5407         }
5408
5409       /* RFC 2047 decode */
5410
5411       case EOP_RFC2047D:
5412         {
5413         int len;
5414         uschar *error;
5415         uschar *decoded = rfc2047_decode(sub, check_rfc2047_length,
5416           headers_charset, '?', &len, &error);
5417         if (error != NULL)
5418           {
5419           expand_string_message = error;
5420           goto EXPAND_FAILED;
5421           }
5422         yield = string_cat(yield, &size, &ptr, decoded, len);
5423         continue;
5424         }
5425
5426       /* from_utf8 converts UTF-8 to 8859-1, turning non-existent chars into
5427       underscores */
5428
5429       case EOP_FROM_UTF8:
5430         {
5431         while (*sub != 0)
5432           {
5433           int c;
5434           uschar buff[4];
5435           GETUTF8INC(c, sub);
5436           if (c > 255) c = '_';
5437           buff[0] = c;
5438           yield = string_cat(yield, &size, &ptr, buff, 1);
5439           }
5440         continue;
5441         }
5442
5443       /* escape turns all non-printing characters into escape sequences. */
5444
5445       case EOP_ESCAPE:
5446         {
5447         uschar *t = string_printing(sub);
5448         yield = string_cat(yield, &size, &ptr, t, Ustrlen(t));
5449         continue;
5450         }
5451
5452       /* Handle numeric expression evaluation */
5453
5454       case EOP_EVAL:
5455       case EOP_EVAL10:
5456         {
5457         uschar *save_sub = sub;
5458         uschar *error = NULL;
5459         int n = eval_expr(&sub, (c == EOP_EVAL10), &error, FALSE);
5460         if (error != NULL)
5461           {
5462           expand_string_message = string_sprintf("error in expression "
5463             "evaluation: %s (after processing \"%.*s\")", error, sub-save_sub,
5464               save_sub);
5465           goto EXPAND_FAILED;
5466           }
5467         sprintf(CS var_buffer, "%d", n);
5468         yield = string_cat(yield, &size, &ptr, var_buffer, Ustrlen(var_buffer));
5469         continue;
5470         }
5471
5472       /* Handle time period formating */
5473
5474       case EOP_TIME_EVAL:
5475         {
5476         int n = readconf_readtime(sub, 0, FALSE);
5477         if (n < 0)
5478           {
5479           expand_string_message = string_sprintf("string \"%s\" is not an "
5480             "Exim time interval in \"%s\" operator", sub, name);
5481           goto EXPAND_FAILED;
5482           }
5483         sprintf(CS var_buffer, "%d", n);
5484         yield = string_cat(yield, &size, &ptr, var_buffer, Ustrlen(var_buffer));
5485         continue;
5486         }
5487
5488       case EOP_TIME_INTERVAL:
5489         {
5490         int n;
5491         uschar *t = read_number(&n, sub);
5492         if (*t != 0) /* Not A Number*/
5493           {
5494           expand_string_message = string_sprintf("string \"%s\" is not a "
5495             "positive number in \"%s\" operator", sub, name);
5496           goto EXPAND_FAILED;
5497           }
5498         t = readconf_printtime(n);
5499         yield = string_cat(yield, &size, &ptr, t, Ustrlen(t));
5500         continue;
5501         }
5502
5503       /* Convert string to base64 encoding */
5504
5505       case EOP_STR2B64:
5506         {
5507         uschar *encstr = auth_b64encode(sub, Ustrlen(sub));
5508         yield = string_cat(yield, &size, &ptr, encstr, Ustrlen(encstr));
5509         continue;
5510         }
5511
5512       /* strlen returns the length of the string */
5513
5514       case EOP_STRLEN:
5515         {
5516         uschar buff[24];
5517         (void)sprintf(CS buff, "%d", Ustrlen(sub));
5518         yield = string_cat(yield, &size, &ptr, buff, Ustrlen(buff));
5519         continue;
5520         }
5521
5522       /* length_n or l_n takes just the first n characters or the whole string,
5523       whichever is the shorter;
5524
5525       substr_m_n, and s_m_n take n characters from offset m; negative m take
5526       from the end; l_n is synonymous with s_0_n. If n is omitted in substr it
5527       takes the rest, either to the right or to the left.
5528
5529       hash_n or h_n makes a hash of length n from the string, yielding n
5530       characters from the set a-z; hash_n_m makes a hash of length n, but
5531       uses m characters from the set a-zA-Z0-9.
5532
5533       nhash_n returns a single number between 0 and n-1 (in text form), while
5534       nhash_n_m returns a div/mod hash as two numbers "a/b". The first lies
5535       between 0 and n-1 and the second between 0 and m-1. */
5536
5537       case EOP_LENGTH:
5538       case EOP_L:
5539       case EOP_SUBSTR:
5540       case EOP_S:
5541       case EOP_HASH:
5542       case EOP_H:
5543       case EOP_NHASH:
5544       case EOP_NH:
5545         {
5546         int sign = 1;
5547         int value1 = 0;
5548         int value2 = -1;
5549         int *pn;
5550         int len;
5551         uschar *ret;
5552
5553         if (arg == NULL)
5554           {
5555           expand_string_message = string_sprintf("missing values after %s",
5556             name);
5557           goto EXPAND_FAILED;
5558           }
5559
5560         /* "length" has only one argument, effectively being synonymous with
5561         substr_0_n. */
5562
5563         if (c == EOP_LENGTH || c == EOP_L)
5564           {
5565           pn = &value2;
5566           value2 = 0;
5567           }
5568
5569         /* The others have one or two arguments; for "substr" the first may be
5570         negative. The second being negative means "not supplied". */
5571
5572         else
5573           {
5574           pn = &value1;
5575           if (name[0] == 's' && *arg == '-') { sign = -1; arg++; }
5576           }
5577
5578         /* Read up to two numbers, separated by underscores */
5579
5580         ret = arg;
5581         while (*arg != 0)
5582           {
5583           if (arg != ret && *arg == '_' && pn == &value1)
5584             {
5585             pn = &value2;
5586             value2 = 0;
5587             if (arg[1] != 0) arg++;
5588             }
5589           else if (!isdigit(*arg))
5590             {
5591             expand_string_message =
5592               string_sprintf("non-digit after underscore in \"%s\"", name);
5593             goto EXPAND_FAILED;
5594             }
5595           else *pn = (*pn)*10 + *arg++ - '0';
5596           }
5597         value1 *= sign;
5598
5599         /* Perform the required operation */
5600
5601         ret =
5602           (c == EOP_HASH || c == EOP_H)?
5603              compute_hash(sub, value1, value2, &len) :
5604           (c == EOP_NHASH || c == EOP_NH)?
5605              compute_nhash(sub, value1, value2, &len) :
5606              extract_substr(sub, value1, value2, &len);
5607
5608         if (ret == NULL) goto EXPAND_FAILED;
5609         yield = string_cat(yield, &size, &ptr, ret, len);
5610         continue;
5611         }
5612
5613       /* Stat a path */
5614
5615       case EOP_STAT:
5616         {
5617         uschar *s;
5618         uschar smode[12];
5619         uschar **modetable[3];
5620         int i;
5621         mode_t mode;
5622         struct stat st;
5623
5624         if ((expand_forbid & RDO_EXISTS) != 0)
5625           {
5626           expand_string_message = US"Use of the stat() expansion is not permitted";
5627           goto EXPAND_FAILED;
5628           }
5629
5630         if (stat(CS sub, &st) < 0)
5631           {
5632           expand_string_message = string_sprintf("stat(%s) failed: %s",
5633             sub, strerror(errno));
5634           goto EXPAND_FAILED;
5635           }
5636         mode = st.st_mode;
5637         switch (mode & S_IFMT)
5638           {
5639           case S_IFIFO: smode[0] = 'p'; break;
5640           case S_IFCHR: smode[0] = 'c'; break;
5641           case S_IFDIR: smode[0] = 'd'; break;
5642           case S_IFBLK: smode[0] = 'b'; break;
5643           case S_IFREG: smode[0] = '-'; break;
5644           default: smode[0] = '?'; break;
5645           }
5646
5647         modetable[0] = ((mode & 01000) == 0)? mtable_normal : mtable_sticky;
5648         modetable[1] = ((mode & 02000) == 0)? mtable_normal : mtable_setid;
5649         modetable[2] = ((mode & 04000) == 0)? mtable_normal : mtable_setid;
5650
5651         for (i = 0; i < 3; i++)
5652           {
5653           memcpy(CS(smode + 7 - i*3), CS(modetable[i][mode & 7]), 3);
5654           mode >>= 3;
5655           }
5656
5657         smode[10] = 0;
5658         s = string_sprintf("mode=%04lo smode=%s inode=%ld device=%ld links=%ld "
5659           "uid=%ld gid=%ld size=" OFF_T_FMT " atime=%ld mtime=%ld ctime=%ld",
5660           (long)(st.st_mode & 077777), smode, (long)st.st_ino,
5661           (long)st.st_dev, (long)st.st_nlink, (long)st.st_uid,
5662           (long)st.st_gid, st.st_size, (long)st.st_atime,
5663           (long)st.st_mtime, (long)st.st_ctime);
5664         yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
5665         continue;
5666         }
5667
5668       /* Unknown operator */
5669
5670       default:
5671       expand_string_message =
5672         string_sprintf("unknown expansion operator \"%s\"", name);
5673       goto EXPAND_FAILED;
5674       }
5675     }
5676
5677   /* Handle a plain name. If this is the first thing in the expansion, release
5678   the pre-allocated buffer. If the result data is known to be in a new buffer,
5679   newsize will be set to the size of that buffer, and we can just point at that
5680   store instead of copying. Many expansion strings contain just one reference,
5681   so this is a useful optimization, especially for humungous headers
5682   ($message_headers). */
5683
5684   if (*s++ == '}')
5685     {
5686     int len;
5687     int newsize = 0;
5688     if (ptr == 0)
5689       {
5690       store_reset(yield);
5691       yield = NULL;
5692       size = 0;
5693       }
5694     value = find_variable(name, FALSE, skipping, &newsize);
5695     if (value == NULL)
5696       {
5697       expand_string_message =
5698         string_sprintf("unknown variable in \"${%s}\"", name);
5699       check_variable_error_message(name);
5700       goto EXPAND_FAILED;
5701       }
5702     len = Ustrlen(value);
5703     if (yield == NULL && newsize != 0)
5704       {
5705       yield = value;
5706       size = newsize;
5707       ptr = len;
5708       }
5709     else yield = string_cat(yield, &size, &ptr, value, len);
5710     continue;
5711     }
5712
5713   /* Else there's something wrong */
5714
5715   expand_string_message =
5716     string_sprintf("\"${%s\" is not a known operator (or a } is missing "
5717     "in a variable reference)", name);
5718   goto EXPAND_FAILED;
5719   }
5720
5721 /* If we hit the end of the string when ket_ends is set, there is a missing
5722 terminating brace. */
5723
5724 if (ket_ends && *s == 0)
5725   {
5726   expand_string_message = malformed_header?
5727     US"missing } at end of string - could be header name not terminated by colon"
5728     :
5729     US"missing } at end of string";
5730   goto EXPAND_FAILED;
5731   }
5732
5733 /* Expansion succeeded; yield may still be NULL here if nothing was actually
5734 added to the string. If so, set up an empty string. Add a terminating zero. If
5735 left != NULL, return a pointer to the terminator. */
5736
5737 if (yield == NULL) yield = store_get(1);
5738 yield[ptr] = 0;
5739 if (left != NULL) *left = s;
5740
5741 /* Any stacking store that was used above the final string is no longer needed.
5742 In many cases the final string will be the first one that was got and so there
5743 will be optimal store usage. */
5744
5745 store_reset(yield + ptr + 1);
5746 DEBUG(D_expand)
5747   {
5748   debug_printf("expanding: %.*s\n   result: %s\n", (int)(s - string), string,
5749     yield);
5750   if (skipping) debug_printf("skipping: result is not used\n");
5751   }
5752 return yield;
5753
5754 /* This is the failure exit: easiest to program with a goto. We still need
5755 to update the pointer to the terminator, for cases of nested calls with "fail".
5756 */
5757
5758 EXPAND_FAILED_CURLY:
5759 expand_string_message = malformed_header?
5760   US"missing or misplaced { or } - could be header name not terminated by colon"
5761   :
5762   US"missing or misplaced { or }";
5763
5764 /* At one point, Exim reset the store to yield (if yield was not NULL), but
5765 that is a bad idea, because expand_string_message is in dynamic store. */
5766
5767 EXPAND_FAILED:
5768 if (left != NULL) *left = s;
5769 DEBUG(D_expand)
5770   {
5771   debug_printf("failed to expand: %s\n", string);
5772   debug_printf("   error message: %s\n", expand_string_message);
5773   if (expand_string_forcedfail) debug_printf("failure was forced\n");
5774   }
5775 return NULL;
5776 }
5777
5778
5779 /* This is the external function call. Do a quick check for any expansion
5780 metacharacters, and if there are none, just return the input string.
5781
5782 Argument: the string to be expanded
5783 Returns:  the expanded string, or NULL if expansion failed; if failure was
5784           due to a lookup deferring, search_find_defer will be TRUE
5785 */
5786
5787 uschar *
5788 expand_string(uschar *string)
5789 {
5790 search_find_defer = FALSE;
5791 malformed_header = FALSE;
5792 return (Ustrpbrk(string, "$\\") == NULL)? string :
5793   expand_string_internal(string, FALSE, NULL, FALSE);
5794 }
5795
5796
5797
5798 /*************************************************
5799 *              Expand and copy                   *
5800 *************************************************/
5801
5802 /* Now and again we want to expand a string and be sure that the result is in a
5803 new bit of store. This function does that.
5804
5805 Argument: the string to be expanded
5806 Returns:  the expanded string, always in a new bit of store, or NULL
5807 */
5808
5809 uschar *
5810 expand_string_copy(uschar *string)
5811 {
5812 uschar *yield = expand_string(string);
5813 if (yield == string) yield = string_copy(string);
5814 return yield;
5815 }
5816
5817
5818
5819 /*************************************************
5820 *        Expand and interpret as an integer      *
5821 *************************************************/
5822
5823 /* Expand a string, and convert the result into an integer.
5824
5825 Arguments:
5826   string  the string to be expanded
5827   isplus  TRUE if a non-negative number is expected
5828
5829 Returns:  the integer value, or
5830           -1 for an expansion error               ) in both cases, message in
5831           -2 for an integer interpretation error  ) expand_string_message
5832           expand_string_message is set NULL for an OK integer
5833 */
5834
5835 int
5836 expand_string_integer(uschar *string, BOOL isplus)
5837 {
5838 long int value;
5839 uschar *s = expand_string(string);
5840 uschar *msg = US"invalid integer \"%s\"";
5841 uschar *endptr;
5842
5843 /* If expansion failed, expand_string_message will be set. */
5844
5845 if (s == NULL) return -1;
5846
5847 /* On an overflow, strtol() returns LONG_MAX or LONG_MIN, and sets errno
5848 to ERANGE. When there isn't an overflow, errno is not changed, at least on some
5849 systems, so we set it zero ourselves. */
5850
5851 errno = 0;
5852 expand_string_message = NULL;               /* Indicates no error */
5853 value = strtol(CS s, CSS &endptr, 10);
5854
5855 if (endptr == s)
5856   {
5857   msg = US"integer expected but \"%s\" found";
5858   }
5859 else if (value < 0 && isplus)
5860   {
5861   msg = US"non-negative integer expected but \"%s\" found";
5862   }
5863 else
5864   {
5865   /* Ensure we can cast this down to an int */
5866   if (value > INT_MAX  || value < INT_MIN) errno = ERANGE;
5867
5868   if (errno != ERANGE)
5869     {
5870     if (tolower(*endptr) == 'k')
5871       {
5872       if (value > INT_MAX/1024 || value < INT_MIN/1024) errno = ERANGE;
5873         else value *= 1024;
5874       endptr++;
5875       }
5876     else if (tolower(*endptr) == 'm')
5877       {
5878       if (value > INT_MAX/(1024*1024) || value < INT_MIN/(1024*1024))
5879         errno = ERANGE;
5880       else value *= 1024*1024;
5881       endptr++;
5882       }
5883     }
5884   if (errno == ERANGE)
5885     msg = US"absolute value of integer \"%s\" is too large (overflow)";
5886   else
5887     {
5888     while (isspace(*endptr)) endptr++;
5889     if (*endptr == 0) return (int)value;
5890     }
5891   }
5892
5893 expand_string_message = string_sprintf(CS msg, s);
5894 return -2;
5895 }
5896
5897
5898 /*************************************************
5899 **************************************************
5900 *             Stand-alone test program           *
5901 **************************************************
5902 *************************************************/
5903
5904 #ifdef STAND_ALONE
5905
5906
5907 BOOL
5908 regex_match_and_setup(const pcre *re, uschar *subject, int options, int setup)
5909 {
5910 int ovector[3*(EXPAND_MAXN+1)];
5911 int n = pcre_exec(re, NULL, subject, Ustrlen(subject), 0, PCRE_EOPT|options,
5912   ovector, sizeof(ovector)/sizeof(int));
5913 BOOL yield = n >= 0;
5914 if (n == 0) n = EXPAND_MAXN + 1;
5915 if (yield)
5916   {
5917   int nn;
5918   expand_nmax = (setup < 0)? 0 : setup + 1;
5919   for (nn = (setup < 0)? 0 : 2; nn < n*2; nn += 2)
5920     {
5921     expand_nstring[expand_nmax] = subject + ovector[nn];
5922     expand_nlength[expand_nmax++] = ovector[nn+1] - ovector[nn];
5923     }
5924   expand_nmax--;
5925   }
5926 return yield;
5927 }
5928
5929
5930 int main(int argc, uschar **argv)
5931 {
5932 int i;
5933 uschar buffer[1024];
5934
5935 debug_selector = D_v;
5936 debug_file = stderr;
5937 debug_fd = fileno(debug_file);
5938 big_buffer = malloc(big_buffer_size);
5939
5940 for (i = 1; i < argc; i++)
5941   {
5942   if (argv[i][0] == '+')
5943     {
5944     debug_trace_memory = 2;
5945     argv[i]++;
5946     }
5947   if (isdigit(argv[i][0]))
5948     debug_selector = Ustrtol(argv[i], NULL, 0);
5949   else
5950     if (Ustrspn(argv[i], "abcdefghijklmnopqrtsuvwxyz0123456789-.:/") ==
5951         Ustrlen(argv[i]))
5952       {
5953       #ifdef LOOKUP_LDAP
5954       eldap_default_servers = argv[i];
5955       #endif
5956       #ifdef LOOKUP_MYSQL
5957       mysql_servers = argv[i];
5958       #endif
5959       #ifdef LOOKUP_PGSQL
5960       pgsql_servers = argv[i];
5961       #endif
5962       }
5963   #ifdef EXIM_PERL
5964   else opt_perl_startup = argv[i];
5965   #endif
5966   }
5967
5968 printf("Testing string expansion: debug_level = %d\n\n", debug_level);
5969
5970 expand_nstring[1] = US"string 1....";
5971 expand_nlength[1] = 8;
5972 expand_nmax = 1;
5973
5974 #ifdef EXIM_PERL
5975 if (opt_perl_startup != NULL)
5976   {
5977   uschar *errstr;
5978   printf("Starting Perl interpreter\n");
5979   errstr = init_perl(opt_perl_startup);
5980   if (errstr != NULL)
5981     {
5982     printf("** error in perl_startup code: %s\n", errstr);
5983     return EXIT_FAILURE;
5984     }
5985   }
5986 #endif /* EXIM_PERL */
5987
5988 while (fgets(buffer, sizeof(buffer), stdin) != NULL)
5989   {
5990   void *reset_point = store_get(0);
5991   uschar *yield = expand_string(buffer);
5992   if (yield != NULL)
5993     {
5994     printf("%s\n", yield);
5995     store_reset(reset_point);
5996     }
5997   else
5998     {
5999     if (search_find_defer) printf("search_find deferred\n");
6000     printf("Failed: %s\n", expand_string_message);
6001     if (expand_string_forcedfail) printf("Forced failure\n");
6002     printf("\n");
6003     }
6004   }
6005
6006 search_tidyup();
6007
6008 return 0;
6009 }
6010
6011 #endif
6012
6013 /* End of expand.c */