src/src/expand.c

   1 /* $Cambridge: exim/src/src/expand.c,v 1.90 2007/08/23 11:01:49 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         if (message_body_newlines)   /* Separate loops for efficiency */
1510           {
1511           while (len > 0)
1512             { if (body[--len] == 0) body[len] = ' '; }
1513           }
1514         else
1515           {
1516           while (len > 0)
1517             { if (body[--len] == '\n' || body[len] == 0) body[len] = ' '; }
1518           }
1519         }
1520       }
1521     return (*ss == NULL)? US"" : *ss;
1522
1523     case vtype_todbsdin:                       /* BSD inbox time of day */
1524     return tod_stamp(tod_bsdin);
1525
1526     case vtype_tode:                           /* Unix epoch time of day */
1527     return tod_stamp(tod_epoch);
1528
1529     case vtype_todf:                           /* Full time of day */
1530     return tod_stamp(tod_full);
1531
1532     case vtype_todl:                           /* Log format time of day */
1533     return tod_stamp(tod_log_bare);            /* (without timezone) */
1534
1535     case vtype_todzone:                        /* Time zone offset only */
1536     return tod_stamp(tod_zone);
1537
1538     case vtype_todzulu:                        /* Zulu time */
1539     return tod_stamp(tod_zulu);
1540
1541     case vtype_todlf:                          /* Log file datestamp tod */
1542     return tod_stamp(tod_log_datestamp);
1543
1544     case vtype_reply:                          /* Get reply address */
1545     s = find_header(US"reply-to:", exists_only, newsize, TRUE,
1546       headers_charset);
1547     if (s != NULL) while (isspace(*s)) s++;
1548     if (s == NULL || *s == 0)
1549       {
1550       *newsize = 0;                            /* For the *s==0 case */
1551       s = find_header(US"from:", exists_only, newsize, TRUE, headers_charset);
1552       }
1553     if (s != NULL)
1554       {
1555       uschar *t;
1556       while (isspace(*s)) s++;
1557       for (t = s; *t != 0; t++) if (*t == '\n') *t = ' ';
1558       while (t > s && isspace(t[-1])) t--;
1559       *t = 0;
1560       }
1561     return (s == NULL)? US"" : s;
1562
1563     /* A recipients list is available only during system message filtering,
1564     during ACL processing after DATA, and while expanding pipe commands
1565     generated from a system filter, but not elsewhere. */
1566
1567     case vtype_recipients:
1568     if (!enable_dollar_recipients) return NULL; else
1569       {
1570       int size = 128;
1571       int ptr = 0;
1572       int i;
1573       s = store_get(size);
1574       for (i = 0; i < recipients_count; i++)
1575         {
1576         if (i != 0) s = string_cat(s, &size, &ptr, US", ", 2);
1577         s = string_cat(s, &size, &ptr, recipients_list[i].address,
1578           Ustrlen(recipients_list[i].address));
1579         }
1580       s[ptr] = 0;     /* string_cat() leaves room */
1581       }
1582     return s;
1583
1584     case vtype_pspace:
1585       {
1586       int inodes;
1587       sprintf(CS var_buffer, "%d",
1588         receive_statvfs(var_table[middle].value == (void *)TRUE, &inodes));
1589       }
1590     return var_buffer;
1591
1592     case vtype_pinodes:
1593       {
1594       int inodes;
1595       (void) receive_statvfs(var_table[middle].value == (void *)TRUE, &inodes);
1596       sprintf(CS var_buffer, "%d", inodes);
1597       }
1598     return var_buffer;
1599     }
1600   }
1601
1602 return NULL;          /* Unknown variable name */
1603 }
1604
1605
1606
1607
1608 /*************************************************
1609 *           Read and expand substrings           *
1610 *************************************************/
1611
1612 /* This function is called to read and expand argument substrings for various
1613 expansion items. Some have a minimum requirement that is less than the maximum;
1614 in these cases, the first non-present one is set to NULL.
1615
1616 Arguments:
1617   sub        points to vector of pointers to set
1618   n          maximum number of substrings
1619   m          minimum required
1620   sptr       points to current string pointer
1621   skipping   the skipping flag
1622   check_end  if TRUE, check for final '}'
1623   name       name of item, for error message
1624
1625 Returns:     0 OK; string pointer updated
1626              1 curly bracketing error (too few arguments)
1627              2 too many arguments (only if check_end is set); message set
1628              3 other error (expansion failure)
1629 */
1630
1631 static int
1632 read_subs(uschar **sub, int n, int m, uschar **sptr, BOOL skipping,
1633   BOOL check_end, uschar *name)
1634 {
1635 int i;
1636 uschar *s = *sptr;
1637
1638 while (isspace(*s)) s++;
1639 for (i = 0; i < n; i++)
1640   {
1641   if (*s != '{')
1642     {
1643     if (i < m) return 1;
1644     sub[i] = NULL;
1645     break;
1646     }
1647   sub[i] = expand_string_internal(s+1, TRUE, &s, skipping);
1648   if (sub[i] == NULL) return 3;
1649   if (*s++ != '}') return 1;
1650   while (isspace(*s)) s++;
1651   }
1652 if (check_end && *s++ != '}')
1653   {
1654   if (s[-1] == '{')
1655     {
1656     expand_string_message = string_sprintf("Too many arguments for \"%s\" "
1657       "(max is %d)", name, n);
1658     return 2;
1659     }
1660   return 1;
1661   }
1662
1663 *sptr = s;
1664 return 0;
1665 }
1666
1667
1668
1669
1670 /*************************************************
1671 *     Elaborate message for bad variable         *
1672 *************************************************/
1673
1674 /* For the "unknown variable" message, take a look at the variable's name, and
1675 give additional information about possible ACL variables. The extra information
1676 is added on to expand_string_message.
1677
1678 Argument:   the name of the variable
1679 Returns:    nothing
1680 */
1681
1682 static void
1683 check_variable_error_message(uschar *name)
1684 {
1685 if (Ustrncmp(name, "acl_", 4) == 0)
1686   expand_string_message = string_sprintf("%s (%s)", expand_string_message,
1687     (name[4] == 'c' || name[4] == 'm')?
1688       (isalpha(name[5])?
1689         US"6th character of a user-defined ACL variable must be a digit or underscore" :
1690         US"strict_acl_vars is set"    /* Syntax is OK, it has to be this */
1691       ) :
1692       US"user-defined ACL variables must start acl_c or acl_m");
1693 }
1694
1695
1696
1697 /*************************************************
1698 *        Read and evaluate a condition           *
1699 *************************************************/
1700
1701 /*
1702 Arguments:
1703   s        points to the start of the condition text
1704   yield    points to a BOOL to hold the result of the condition test;
1705            if NULL, we are just reading through a condition that is
1706            part of an "or" combination to check syntax, or in a state
1707            where the answer isn't required
1708
1709 Returns:   a pointer to the first character after the condition, or
1710            NULL after an error
1711 */
1712
1713 static uschar *
1714 eval_condition(uschar *s, BOOL *yield)
1715 {
1716 BOOL testfor = TRUE;
1717 BOOL tempcond, combined_cond;
1718 BOOL *subcondptr;
1719 int i, rc, cond_type, roffset;
1720 int num[2];
1721 struct stat statbuf;
1722 uschar name[256];
1723 uschar *sub[4];
1724
1725 const pcre *re;
1726 const uschar *rerror;
1727
1728 for (;;)
1729   {
1730   while (isspace(*s)) s++;
1731   if (*s == '!') { testfor = !testfor; s++; } else break;
1732   }
1733
1734 /* Numeric comparisons are symbolic */
1735
1736 if (*s == '=' || *s == '>' || *s == '<')
1737   {
1738   int p = 0;
1739   name[p++] = *s++;
1740   if (*s == '=')
1741     {
1742     name[p++] = '=';
1743     s++;
1744     }
1745   name[p] = 0;
1746   }
1747
1748 /* All other conditions are named */
1749
1750 else s = read_name(name, 256, s, US"_");
1751
1752 /* If we haven't read a name, it means some non-alpha character is first. */
1753
1754 if (name[0] == 0)
1755   {
1756   expand_string_message = string_sprintf("condition name expected, "
1757     "but found \"%.16s\"", s);
1758   return NULL;
1759   }
1760
1761 /* Find which condition we are dealing with, and switch on it */
1762
1763 cond_type = chop_match(name, cond_table, sizeof(cond_table)/sizeof(uschar *));
1764 switch(cond_type)
1765   {
1766   /* def: tests for a non-empty variable, or for the existence of a header. If
1767   yield == NULL we are in a skipping state, and don't care about the answer. */
1768
1769   case ECOND_DEF:
1770   if (*s != ':')
1771     {
1772     expand_string_message = US"\":\" expected after \"def\"";
1773     return NULL;
1774     }
1775
1776   s = read_name(name, 256, s+1, US"_");
1777
1778   /* Test for a header's existence. If the name contains a closing brace
1779   character, this may be a user error where the terminating colon has been
1780   omitted. Set a flag to adjust a subsequent error message in this case. */
1781
1782   if (Ustrncmp(name, "h_", 2) == 0 ||
1783       Ustrncmp(name, "rh_", 3) == 0 ||
1784       Ustrncmp(name, "bh_", 3) == 0 ||
1785       Ustrncmp(name, "header_", 7) == 0 ||
1786       Ustrncmp(name, "rheader_", 8) == 0 ||
1787       Ustrncmp(name, "bheader_", 8) == 0)
1788     {
1789     s = read_header_name(name, 256, s);
1790     if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
1791     if (yield != NULL) *yield =
1792       (find_header(name, TRUE, NULL, FALSE, NULL) != NULL) == testfor;
1793     }
1794
1795   /* Test for a variable's having a non-empty value. A non-existent variable
1796   causes an expansion failure. */
1797
1798   else
1799     {
1800     uschar *value = find_variable(name, TRUE, yield == NULL, NULL);
1801     if (value == NULL)
1802       {
1803       expand_string_message = (name[0] == 0)?
1804         string_sprintf("variable name omitted after \"def:\"") :
1805         string_sprintf("unknown variable \"%s\" after \"def:\"", name);
1806       check_variable_error_message(name);
1807       return NULL;
1808       }
1809     if (yield != NULL) *yield = (value[0] != 0) == testfor;
1810     }
1811
1812   return s;
1813
1814
1815   /* first_delivery tests for first delivery attempt */
1816
1817   case ECOND_FIRST_DELIVERY:
1818   if (yield != NULL) *yield = deliver_firsttime == testfor;
1819   return s;
1820
1821
1822   /* queue_running tests for any process started by a queue runner */
1823
1824   case ECOND_QUEUE_RUNNING:
1825   if (yield != NULL) *yield = (queue_run_pid != (pid_t)0) == testfor;
1826   return s;
1827
1828
1829   /* exists:  tests for file existence
1830        isip:  tests for any IP address
1831       isip4:  tests for an IPv4 address
1832       isip6:  tests for an IPv6 address
1833         pam:  does PAM authentication
1834      radius:  does RADIUS authentication
1835    ldapauth:  does LDAP authentication
1836     pwcheck:  does Cyrus SASL pwcheck authentication
1837   */
1838
1839   case ECOND_EXISTS:
1840   case ECOND_ISIP:
1841   case ECOND_ISIP4:
1842   case ECOND_ISIP6:
1843   case ECOND_PAM:
1844   case ECOND_RADIUS:
1845   case ECOND_LDAPAUTH:
1846   case ECOND_PWCHECK:
1847
1848   while (isspace(*s)) s++;
1849   if (*s != '{') goto COND_FAILED_CURLY_START;
1850
1851   sub[0] = expand_string_internal(s+1, TRUE, &s, yield == NULL);
1852   if (sub[0] == NULL) return NULL;
1853   if (*s++ != '}') goto COND_FAILED_CURLY_END;
1854
1855   if (yield == NULL) return s;   /* No need to run the test if skipping */
1856
1857   switch(cond_type)
1858     {
1859     case ECOND_EXISTS:
1860     if ((expand_forbid & RDO_EXISTS) != 0)
1861       {
1862       expand_string_message = US"File existence tests are not permitted";
1863       return NULL;
1864       }
1865     *yield = (Ustat(sub[0], &statbuf) == 0) == testfor;
1866     break;
1867
1868     case ECOND_ISIP:
1869     case ECOND_ISIP4:
1870     case ECOND_ISIP6:
1871     rc = string_is_ip_address(sub[0], NULL);
1872     *yield = ((cond_type == ECOND_ISIP)? (rc != 0) :
1873              (cond_type == ECOND_ISIP4)? (rc == 4) : (rc == 6)) == testfor;
1874     break;
1875
1876     /* Various authentication tests - all optionally compiled */
1877
1878     case ECOND_PAM:
1879     #ifdef SUPPORT_PAM
1880     rc = auth_call_pam(sub[0], &expand_string_message);
1881     goto END_AUTH;
1882     #else
1883     goto COND_FAILED_NOT_COMPILED;
1884     #endif  /* SUPPORT_PAM */
1885
1886     case ECOND_RADIUS:
1887     #ifdef RADIUS_CONFIG_FILE
1888     rc = auth_call_radius(sub[0], &expand_string_message);
1889     goto END_AUTH;
1890     #else
1891     goto COND_FAILED_NOT_COMPILED;
1892     #endif  /* RADIUS_CONFIG_FILE */
1893
1894     case ECOND_LDAPAUTH:
1895     #ifdef LOOKUP_LDAP
1896       {
1897       /* Just to keep the interface the same */
1898       BOOL do_cache;
1899       int old_pool = store_pool;
1900       store_pool = POOL_SEARCH;
1901       rc = eldapauth_find((void *)(-1), NULL, sub[0], Ustrlen(sub[0]), NULL,
1902         &expand_string_message, &do_cache);
1903       store_pool = old_pool;
1904       }
1905     goto END_AUTH;
1906     #else
1907     goto COND_FAILED_NOT_COMPILED;
1908     #endif  /* LOOKUP_LDAP */
1909
1910     case ECOND_PWCHECK:
1911     #ifdef CYRUS_PWCHECK_SOCKET
1912     rc = auth_call_pwcheck(sub[0], &expand_string_message);
1913     goto END_AUTH;
1914     #else
1915     goto COND_FAILED_NOT_COMPILED;
1916     #endif  /* CYRUS_PWCHECK_SOCKET */
1917
1918     #if defined(SUPPORT_PAM) || defined(RADIUS_CONFIG_FILE) || \
1919         defined(LOOKUP_LDAP) || defined(CYRUS_PWCHECK_SOCKET)
1920     END_AUTH:
1921     if (rc == ERROR || rc == DEFER) return NULL;
1922     *yield = (rc == OK) == testfor;
1923     #endif
1924     }
1925   return s;
1926
1927
1928   /* saslauthd: does Cyrus saslauthd authentication. Four parameters are used:
1929
1930      ${if saslauthd {{username}{password}{service}{realm}}  {yes}[no}}
1931
1932   However, the last two are optional. That is why the whole set is enclosed
1933   in their own set or braces. */
1934
1935   case ECOND_SASLAUTHD:
1936   #ifndef CYRUS_SASLAUTHD_SOCKET
1937   goto COND_FAILED_NOT_COMPILED;
1938   #else
1939   while (isspace(*s)) s++;
1940   if (*s++ != '{') goto COND_FAILED_CURLY_START;
1941   switch(read_subs(sub, 4, 2, &s, yield == NULL, TRUE, US"saslauthd"))
1942     {
1943     case 1: expand_string_message = US"too few arguments or bracketing "
1944       "error for saslauthd";
1945     case 2:
1946     case 3: return NULL;
1947     }
1948   if (sub[2] == NULL) sub[3] = NULL;  /* realm if no service */
1949   if (yield != NULL)
1950     {
1951     int rc;
1952     rc = auth_call_saslauthd(sub[0], sub[1], sub[2], sub[3],
1953       &expand_string_message);
1954     if (rc == ERROR || rc == DEFER) return NULL;
1955     *yield = (rc == OK) == testfor;
1956     }
1957   return s;
1958   #endif /* CYRUS_SASLAUTHD_SOCKET */
1959
1960
1961   /* symbolic operators for numeric and string comparison, and a number of
1962   other operators, all requiring two arguments.
1963
1964   match:             does a regular expression match and sets up the numerical
1965                        variables if it succeeds
1966   match_address:     matches in an address list
1967   match_domain:      matches in a domain list
1968   match_ip:          matches a host list that is restricted to IP addresses
1969   match_local_part:  matches in a local part list
1970   crypteq:           encrypts plaintext and compares against an encrypted text,
1971                        using crypt(), crypt16(), MD5 or SHA-1
1972   */
1973
1974   case ECOND_MATCH:
1975   case ECOND_MATCH_ADDRESS:
1976   case ECOND_MATCH_DOMAIN:
1977   case ECOND_MATCH_IP:
1978   case ECOND_MATCH_LOCAL_PART:
1979   case ECOND_CRYPTEQ:
1980
1981   case ECOND_NUM_L:     /* Numerical comparisons */
1982   case ECOND_NUM_LE:
1983   case ECOND_NUM_E:
1984   case ECOND_NUM_EE:
1985   case ECOND_NUM_G:
1986   case ECOND_NUM_GE:
1987
1988   case ECOND_STR_LT:    /* String comparisons */
1989   case ECOND_STR_LTI:
1990   case ECOND_STR_LE:
1991   case ECOND_STR_LEI:
1992   case ECOND_STR_EQ:
1993   case ECOND_STR_EQI:
1994   case ECOND_STR_GT:
1995   case ECOND_STR_GTI:
1996   case ECOND_STR_GE:
1997   case ECOND_STR_GEI:
1998
1999   for (i = 0; i < 2; i++)
2000     {
2001     while (isspace(*s)) s++;
2002     if (*s != '{')
2003       {
2004       if (i == 0) goto COND_FAILED_CURLY_START;
2005       expand_string_message = string_sprintf("missing 2nd string in {} "
2006         "after \"%s\"", name);
2007       return NULL;
2008       }
2009     sub[i] = expand_string_internal(s+1, TRUE, &s, yield == NULL);
2010     if (sub[i] == NULL) return NULL;
2011     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2012
2013     /* Convert to numerical if required; we know that the names of all the
2014     conditions that compare numbers do not start with a letter. This just saves
2015     checking for them individually. */
2016
2017     if (!isalpha(name[0]) && yield != NULL)
2018       {
2019       if (sub[i][0] == 0)
2020         {
2021         num[i] = 0;
2022         DEBUG(D_expand)
2023           debug_printf("empty string cast to zero for numerical comparison\n");
2024         }
2025       else
2026         {
2027         num[i] = expand_string_integer(sub[i], FALSE);
2028         if (expand_string_message != NULL) return NULL;
2029         }
2030       }
2031     }
2032
2033   /* Result not required */
2034
2035   if (yield == NULL) return s;
2036
2037   /* Do an appropriate comparison */
2038
2039   switch(cond_type)
2040     {
2041     case ECOND_NUM_E:
2042     case ECOND_NUM_EE:
2043     *yield = (num[0] == num[1]) == testfor;
2044     break;
2045
2046     case ECOND_NUM_G:
2047     *yield = (num[0] > num[1]) == testfor;
2048     break;
2049
2050     case ECOND_NUM_GE:
2051     *yield = (num[0] >= num[1]) == testfor;
2052     break;
2053
2054     case ECOND_NUM_L:
2055     *yield = (num[0] < num[1]) == testfor;
2056     break;
2057
2058     case ECOND_NUM_LE:
2059     *yield = (num[0] <= num[1]) == testfor;
2060     break;
2061
2062     case ECOND_STR_LT:
2063     *yield = (Ustrcmp(sub[0], sub[1]) < 0) == testfor;
2064     break;
2065
2066     case ECOND_STR_LTI:
2067     *yield = (strcmpic(sub[0], sub[1]) < 0) == testfor;
2068     break;
2069
2070     case ECOND_STR_LE:
2071     *yield = (Ustrcmp(sub[0], sub[1]) <= 0) == testfor;
2072     break;
2073
2074     case ECOND_STR_LEI:
2075     *yield = (strcmpic(sub[0], sub[1]) <= 0) == testfor;
2076     break;
2077
2078     case ECOND_STR_EQ:
2079     *yield = (Ustrcmp(sub[0], sub[1]) == 0) == testfor;
2080     break;
2081
2082     case ECOND_STR_EQI:
2083     *yield = (strcmpic(sub[0], sub[1]) == 0) == testfor;
2084     break;
2085
2086     case ECOND_STR_GT:
2087     *yield = (Ustrcmp(sub[0], sub[1]) > 0) == testfor;
2088     break;
2089
2090     case ECOND_STR_GTI:
2091     *yield = (strcmpic(sub[0], sub[1]) > 0) == testfor;
2092     break;
2093
2094     case ECOND_STR_GE:
2095     *yield = (Ustrcmp(sub[0], sub[1]) >= 0) == testfor;
2096     break;
2097
2098     case ECOND_STR_GEI:
2099     *yield = (strcmpic(sub[0], sub[1]) >= 0) == testfor;
2100     break;
2101
2102     case ECOND_MATCH:   /* Regular expression match */
2103     re = pcre_compile(CS sub[1], PCRE_COPT, (const char **)&rerror, &roffset,
2104       NULL);
2105     if (re == NULL)
2106       {
2107       expand_string_message = string_sprintf("regular expression error in "
2108         "\"%s\": %s at offset %d", sub[1], rerror, roffset);
2109       return NULL;
2110       }
2111     *yield = regex_match_and_setup(re, sub[0], 0, -1) == testfor;
2112     break;
2113
2114     case ECOND_MATCH_ADDRESS:  /* Match in an address list */
2115     rc = match_address_list(sub[0], TRUE, FALSE, &(sub[1]), NULL, -1, 0, NULL);
2116     goto MATCHED_SOMETHING;
2117
2118     case ECOND_MATCH_DOMAIN:   /* Match in a domain list */
2119     rc = match_isinlist(sub[0], &(sub[1]), 0, &domainlist_anchor, NULL,
2120       MCL_DOMAIN + MCL_NOEXPAND, TRUE, NULL);
2121     goto MATCHED_SOMETHING;
2122
2123     case ECOND_MATCH_IP:       /* Match IP address in a host list */
2124     if (sub[0][0] != 0 && string_is_ip_address(sub[0], NULL) == 0)
2125       {
2126       expand_string_message = string_sprintf("\"%s\" is not an IP address",
2127         sub[0]);
2128       return NULL;
2129       }
2130     else
2131       {
2132       unsigned int *nullcache = NULL;
2133       check_host_block cb;
2134
2135       cb.host_name = US"";
2136       cb.host_address = sub[0];
2137
2138       /* If the host address starts off ::ffff: it is an IPv6 address in
2139       IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2140       addresses. */
2141
2142       cb.host_ipv4 = (Ustrncmp(cb.host_address, "::ffff:", 7) == 0)?
2143         cb.host_address + 7 : cb.host_address;
2144
2145       rc = match_check_list(
2146              &sub[1],                   /* the list */
2147              0,                         /* separator character */
2148              &hostlist_anchor,          /* anchor pointer */
2149              &nullcache,                /* cache pointer */
2150              check_host,                /* function for testing */
2151              &cb,                       /* argument for function */
2152              MCL_HOST,                  /* type of check */
2153              sub[0],                    /* text for debugging */
2154              NULL);                     /* where to pass back data */
2155       }
2156     goto MATCHED_SOMETHING;
2157
2158     case ECOND_MATCH_LOCAL_PART:
2159     rc = match_isinlist(sub[0], &(sub[1]), 0, &localpartlist_anchor, NULL,
2160       MCL_LOCALPART + MCL_NOEXPAND, TRUE, NULL);
2161     /* Fall through */
2162     /* VVVVVVVVVVVV */
2163     MATCHED_SOMETHING:
2164     switch(rc)
2165       {
2166       case OK:
2167       *yield = testfor;
2168       break;
2169
2170       case FAIL:
2171       *yield = !testfor;
2172       break;
2173
2174       case DEFER:
2175       expand_string_message = string_sprintf("unable to complete match "
2176         "against \"%s\": %s", sub[1], search_error_message);
2177       return NULL;
2178       }
2179
2180     break;
2181
2182     /* Various "encrypted" comparisons. If the second string starts with
2183     "{" then an encryption type is given. Default to crypt() or crypt16()
2184     (build-time choice). */
2185
2186     case ECOND_CRYPTEQ:
2187     #ifndef SUPPORT_CRYPTEQ
2188     goto COND_FAILED_NOT_COMPILED;
2189     #else
2190     if (strncmpic(sub[1], US"{md5}", 5) == 0)
2191       {
2192       int sublen = Ustrlen(sub[1]+5);
2193       md5 base;
2194       uschar digest[16];
2195
2196       md5_start(&base);
2197       md5_end(&base, (uschar *)sub[0], Ustrlen(sub[0]), digest);
2198
2199       /* If the length that we are comparing against is 24, the MD5 digest
2200       is expressed as a base64 string. This is the way LDAP does it. However,
2201       some other software uses a straightforward hex representation. We assume
2202       this if the length is 32. Other lengths fail. */
2203
2204       if (sublen == 24)
2205         {
2206         uschar *coded = auth_b64encode((uschar *)digest, 16);
2207         DEBUG(D_auth) debug_printf("crypteq: using MD5+B64 hashing\n"
2208           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2209         *yield = (Ustrcmp(coded, sub[1]+5) == 0) == testfor;
2210         }
2211       else if (sublen == 32)
2212         {
2213         int i;
2214         uschar coded[36];
2215         for (i = 0; i < 16; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2216         coded[32] = 0;
2217         DEBUG(D_auth) debug_printf("crypteq: using MD5+hex hashing\n"
2218           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2219         *yield = (strcmpic(coded, sub[1]+5) == 0) == testfor;
2220         }
2221       else
2222         {
2223         DEBUG(D_auth) debug_printf("crypteq: length for MD5 not 24 or 32: "
2224           "fail\n  crypted=%s\n", sub[1]+5);
2225         *yield = !testfor;
2226         }
2227       }
2228
2229     else if (strncmpic(sub[1], US"{sha1}", 6) == 0)
2230       {
2231       int sublen = Ustrlen(sub[1]+6);
2232       sha1 base;
2233       uschar digest[20];
2234
2235       sha1_start(&base);
2236       sha1_end(&base, (uschar *)sub[0], Ustrlen(sub[0]), digest);
2237
2238       /* If the length that we are comparing against is 28, assume the SHA1
2239       digest is expressed as a base64 string. If the length is 40, assume a
2240       straightforward hex representation. Other lengths fail. */
2241
2242       if (sublen == 28)
2243         {
2244         uschar *coded = auth_b64encode((uschar *)digest, 20);
2245         DEBUG(D_auth) debug_printf("crypteq: using SHA1+B64 hashing\n"
2246           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2247         *yield = (Ustrcmp(coded, sub[1]+6) == 0) == testfor;
2248         }
2249       else if (sublen == 40)
2250         {
2251         int i;
2252         uschar coded[44];
2253         for (i = 0; i < 20; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2254         coded[40] = 0;
2255         DEBUG(D_auth) debug_printf("crypteq: using SHA1+hex hashing\n"
2256           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2257         *yield = (strcmpic(coded, sub[1]+6) == 0) == testfor;
2258         }
2259       else
2260         {
2261         DEBUG(D_auth) debug_printf("crypteq: length for SHA-1 not 28 or 40: "
2262           "fail\n  crypted=%s\n", sub[1]+6);
2263         *yield = !testfor;
2264         }
2265       }
2266
2267     else   /* {crypt} or {crypt16} and non-{ at start */
2268       {
2269       int which = 0;
2270       uschar *coded;
2271
2272       if (strncmpic(sub[1], US"{crypt}", 7) == 0)
2273         {
2274         sub[1] += 7;
2275         which = 1;
2276         }
2277       else if (strncmpic(sub[1], US"{crypt16}", 9) == 0)
2278         {
2279         sub[1] += 9;
2280         which = 2;
2281         }
2282       else if (sub[1][0] == '{')
2283         {
2284         expand_string_message = string_sprintf("unknown encryption mechanism "
2285           "in \"%s\"", sub[1]);
2286         return NULL;
2287         }
2288
2289       switch(which)
2290         {
2291         case 0:  coded = US DEFAULT_CRYPT(CS sub[0], CS sub[1]); break;
2292         case 1:  coded = US crypt(CS sub[0], CS sub[1]); break;
2293         default: coded = US crypt16(CS sub[0], CS sub[1]); break;
2294         }
2295
2296       #define STR(s) # s
2297       #define XSTR(s) STR(s)
2298       DEBUG(D_auth) debug_printf("crypteq: using %s()\n"
2299         "  subject=%s\n  crypted=%s\n",
2300         (which == 0)? XSTR(DEFAULT_CRYPT) : (which == 1)? "crypt" : "crypt16",
2301         coded, sub[1]);
2302       #undef STR
2303       #undef XSTR
2304
2305       /* If the encrypted string contains fewer than two characters (for the
2306       salt), force failure. Otherwise we get false positives: with an empty
2307       string the yield of crypt() is an empty string! */
2308
2309       *yield = (Ustrlen(sub[1]) < 2)? !testfor :
2310         (Ustrcmp(coded, sub[1]) == 0) == testfor;
2311       }
2312     break;
2313     #endif  /* SUPPORT_CRYPTEQ */
2314     }   /* Switch for comparison conditions */
2315
2316   return s;    /* End of comparison conditions */
2317
2318
2319   /* and/or: computes logical and/or of several conditions */
2320
2321   case ECOND_AND:
2322   case ECOND_OR:
2323   subcondptr = (yield == NULL)? NULL : &tempcond;
2324   combined_cond = (cond_type == ECOND_AND);
2325
2326   while (isspace(*s)) s++;
2327   if (*s++ != '{') goto COND_FAILED_CURLY_START;
2328
2329   for (;;)
2330     {
2331     while (isspace(*s)) s++;
2332     if (*s == '}') break;
2333     if (*s != '{')
2334       {
2335       expand_string_message = string_sprintf("each subcondition "
2336         "inside an \"%s{...}\" condition must be in its own {}", name);
2337       return NULL;
2338       }
2339
2340     s = eval_condition(s+1, subcondptr);
2341     if (s == NULL)
2342       {
2343       expand_string_message = string_sprintf("%s inside \"%s{...}\" condition",
2344         expand_string_message, name);
2345       return NULL;
2346       }
2347     while (isspace(*s)) s++;
2348
2349     if (*s++ != '}')
2350       {
2351       expand_string_message = string_sprintf("missing } at end of condition "
2352         "inside \"%s\" group", name);
2353       return NULL;
2354       }
2355
2356     if (yield != NULL)
2357       {
2358       if (cond_type == ECOND_AND)
2359         {
2360         combined_cond &= tempcond;
2361         if (!combined_cond) subcondptr = NULL;  /* once false, don't */
2362         }                                       /* evaluate any more */
2363       else
2364         {
2365         combined_cond |= tempcond;
2366         if (combined_cond) subcondptr = NULL;   /* once true, don't */
2367         }                                       /* evaluate any more */
2368       }
2369     }
2370
2371   if (yield != NULL) *yield = (combined_cond == testfor);
2372   return ++s;
2373
2374
2375   /* forall/forany: iterates a condition with different values */
2376
2377   case ECOND_FORALL:
2378   case ECOND_FORANY:
2379     {
2380     int sep = 0;
2381     uschar *save_iterate_item = iterate_item;
2382
2383     while (isspace(*s)) s++;
2384     if (*s++ != '{') goto COND_FAILED_CURLY_START;
2385     sub[0] = expand_string_internal(s, TRUE, &s, (yield == NULL));
2386     if (sub[0] == NULL) return NULL;
2387     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2388
2389     while (isspace(*s)) s++;
2390     if (*s++ != '{') goto COND_FAILED_CURLY_START;
2391
2392     sub[1] = s;
2393
2394     /* Call eval_condition once, with result discarded (as if scanning a
2395     "false" part). This allows us to find the end of the condition, because if
2396     the list it empty, we won't actually evaluate the condition for real. */
2397
2398     s = eval_condition(sub[1], NULL);
2399     if (s == NULL)
2400       {
2401       expand_string_message = string_sprintf("%s inside \"%s\" condition",
2402         expand_string_message, name);
2403       return NULL;
2404       }
2405     while (isspace(*s)) s++;
2406
2407     if (*s++ != '}')
2408       {
2409       expand_string_message = string_sprintf("missing } at end of condition "
2410         "inside \"%s\"", name);
2411       return NULL;
2412       }
2413
2414     if (yield != NULL) *yield = !testfor;
2415     while ((iterate_item = string_nextinlist(&sub[0], &sep, NULL, 0)) != NULL)
2416       {
2417       DEBUG(D_expand) debug_printf("%s: $item = \"%s\"\n", name, iterate_item);
2418       if (eval_condition(sub[1], &tempcond) == NULL)
2419         {
2420         expand_string_message = string_sprintf("%s inside \"%s\" condition",
2421           expand_string_message, name);
2422         iterate_item = save_iterate_item;
2423         return NULL;
2424         }
2425       DEBUG(D_expand) debug_printf("%s: condition evaluated to %s\n", name,
2426         tempcond? "true":"false");
2427
2428       if (yield != NULL) *yield = (tempcond == testfor);
2429       if (tempcond == (cond_type == ECOND_FORANY)) break;
2430       }
2431
2432     iterate_item = save_iterate_item;
2433     return s;
2434     }
2435
2436
2437   /* Unknown condition */
2438
2439   default:
2440   expand_string_message = string_sprintf("unknown condition \"%s\"", name);
2441   return NULL;
2442   }   /* End switch on condition type */
2443
2444 /* Missing braces at start and end of data */
2445
2446 COND_FAILED_CURLY_START:
2447 expand_string_message = string_sprintf("missing { after \"%s\"", name);
2448 return NULL;
2449
2450 COND_FAILED_CURLY_END:
2451 expand_string_message = string_sprintf("missing } at end of \"%s\" condition",
2452   name);
2453 return NULL;
2454
2455 /* A condition requires code that is not compiled */
2456
2457 #if !defined(SUPPORT_PAM) || !defined(RADIUS_CONFIG_FILE) || \
2458     !defined(LOOKUP_LDAP) || !defined(CYRUS_PWCHECK_SOCKET) || \
2459     !defined(SUPPORT_CRYPTEQ) || !defined(CYRUS_SASLAUTHD_SOCKET)
2460 COND_FAILED_NOT_COMPILED:
2461 expand_string_message = string_sprintf("support for \"%s\" not compiled",
2462   name);
2463 return NULL;
2464 #endif
2465 }
2466
2467
2468
2469
2470 /*************************************************
2471 *          Save numerical variables              *
2472 *************************************************/
2473
2474 /* This function is called from items such as "if" that want to preserve and
2475 restore the numbered variables.
2476
2477 Arguments:
2478   save_expand_string    points to an array of pointers to set
2479   save_expand_nlength   points to an array of ints for the lengths
2480
2481 Returns:                the value of expand max to save
2482 */
2483
2484 static int
2485 save_expand_strings(uschar **save_expand_nstring, int *save_expand_nlength)
2486 {
2487 int i;
2488 for (i = 0; i <= expand_nmax; i++)
2489   {
2490   save_expand_nstring[i] = expand_nstring[i];
2491   save_expand_nlength[i] = expand_nlength[i];
2492   }
2493 return expand_nmax;
2494 }
2495
2496
2497
2498 /*************************************************
2499 *           Restore numerical variables          *
2500 *************************************************/
2501
2502 /* This function restored saved values of numerical strings.
2503
2504 Arguments:
2505   save_expand_nmax      the number of strings to restore
2506   save_expand_string    points to an array of pointers
2507   save_expand_nlength   points to an array of ints
2508
2509 Returns:                nothing
2510 */
2511
2512 static void
2513 restore_expand_strings(int save_expand_nmax, uschar **save_expand_nstring,
2514   int *save_expand_nlength)
2515 {
2516 int i;
2517 expand_nmax = save_expand_nmax;
2518 for (i = 0; i <= expand_nmax; i++)
2519   {
2520   expand_nstring[i] = save_expand_nstring[i];
2521   expand_nlength[i] = save_expand_nlength[i];
2522   }
2523 }
2524
2525
2526
2527
2528
2529 /*************************************************
2530 *            Handle yes/no substrings            *
2531 *************************************************/
2532
2533 /* This function is used by ${if}, ${lookup} and ${extract} to handle the
2534 alternative substrings that depend on whether or not the condition was true,
2535 or the lookup or extraction succeeded. The substrings always have to be
2536 expanded, to check their syntax, but "skipping" is set when the result is not
2537 needed - this avoids unnecessary nested lookups.
2538
2539 Arguments:
2540   skipping       TRUE if we were skipping when this item was reached
2541   yes            TRUE if the first string is to be used, else use the second
2542   save_lookup    a value to put back into lookup_value before the 2nd expansion
2543   sptr           points to the input string pointer
2544   yieldptr       points to the output string pointer
2545   sizeptr        points to the output string size
2546   ptrptr         points to the output string pointer
2547   type           "lookup" or "if" or "extract" or "run", for error message
2548
2549 Returns:         0 OK; lookup_value has been reset to save_lookup
2550                  1 expansion failed
2551                  2 expansion failed because of bracketing error
2552 */
2553
2554 static int
2555 process_yesno(BOOL skipping, BOOL yes, uschar *save_lookup, uschar **sptr,
2556   uschar **yieldptr, int *sizeptr, int *ptrptr, uschar *type)
2557 {
2558 int rc = 0;
2559 uschar *s = *sptr;    /* Local value */
2560 uschar *sub1, *sub2;
2561
2562 /* If there are no following strings, we substitute the contents of $value for
2563 lookups and for extractions in the success case. For the ${if item, the string
2564 "true" is substituted. In the fail case, nothing is substituted for all three
2565 items. */
2566
2567 while (isspace(*s)) s++;
2568 if (*s == '}')
2569   {
2570   if (type[0] == 'i')
2571     {
2572     if (yes) *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, US"true", 4);
2573     }
2574   else
2575     {
2576     if (yes && lookup_value != NULL)
2577       *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, lookup_value,
2578         Ustrlen(lookup_value));
2579     lookup_value = save_lookup;
2580     }
2581   s++;
2582   goto RETURN;
2583   }
2584
2585 /* The first following string must be braced. */
2586
2587 if (*s++ != '{') goto FAILED_CURLY;
2588
2589 /* Expand the first substring. Forced failures are noticed only if we actually
2590 want this string. Set skipping in the call in the fail case (this will always
2591 be the case if we were already skipping). */
2592
2593 sub1 = expand_string_internal(s, TRUE, &s, !yes);
2594 if (sub1 == NULL && (yes || !expand_string_forcedfail)) goto FAILED;
2595 expand_string_forcedfail = FALSE;
2596 if (*s++ != '}') goto FAILED_CURLY;
2597
2598 /* If we want the first string, add it to the output */
2599
2600 if (yes)
2601   *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, sub1, Ustrlen(sub1));
2602
2603 /* If this is called from a lookup or an extract, we want to restore $value to
2604 what it was at the start of the item, so that it has this value during the
2605 second string expansion. For the call from "if" or "run" to this function,
2606 save_lookup is set to lookup_value, so that this statement does nothing. */
2607
2608 lookup_value = save_lookup;
2609
2610 /* There now follows either another substring, or "fail", or nothing. This
2611 time, forced failures are noticed only if we want the second string. We must
2612 set skipping in the nested call if we don't want this string, or if we were
2613 already skipping. */
2614
2615 while (isspace(*s)) s++;
2616 if (*s == '{')
2617   {
2618   sub2 = expand_string_internal(s+1, TRUE, &s, yes || skipping);
2619   if (sub2 == NULL && (!yes || !expand_string_forcedfail)) goto FAILED;
2620   expand_string_forcedfail = FALSE;
2621   if (*s++ != '}') goto FAILED_CURLY;
2622
2623   /* If we want the second string, add it to the output */
2624
2625   if (!yes)
2626     *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, sub2, Ustrlen(sub2));
2627   }
2628
2629 /* If there is no second string, but the word "fail" is present when the use of
2630 the second string is wanted, set a flag indicating it was a forced failure
2631 rather than a syntactic error. Swallow the terminating } in case this is nested
2632 inside another lookup or if or extract. */
2633
2634 else if (*s != '}')
2635   {
2636   uschar name[256];
2637   s = read_name(name, sizeof(name), s, US"_");
2638   if (Ustrcmp(name, "fail") == 0)
2639     {
2640     if (!yes && !skipping)
2641       {
2642       while (isspace(*s)) s++;
2643       if (*s++ != '}') goto FAILED_CURLY;
2644       expand_string_message =
2645         string_sprintf("\"%s\" failed and \"fail\" requested", type);
2646       expand_string_forcedfail = TRUE;
2647       goto FAILED;
2648       }
2649     }
2650   else
2651     {
2652     expand_string_message =
2653       string_sprintf("syntax error in \"%s\" item - \"fail\" expected", type);
2654     goto FAILED;
2655     }
2656   }
2657
2658 /* All we have to do now is to check on the final closing brace. */
2659
2660 while (isspace(*s)) s++;
2661 if (*s++ == '}') goto RETURN;
2662
2663 /* Get here if there is a bracketing failure */
2664
2665 FAILED_CURLY:
2666 rc++;
2667
2668 /* Get here for other failures */
2669
2670 FAILED:
2671 rc++;
2672
2673 /* Update the input pointer value before returning */
2674
2675 RETURN:
2676 *sptr = s;
2677 return rc;
2678 }
2679
2680
2681
2682
2683 /*************************************************
2684 *    Handle MD5 or SHA-1 computation for HMAC    *
2685 *************************************************/
2686
2687 /* These are some wrapping functions that enable the HMAC code to be a bit
2688 cleaner. A good compiler will spot the tail recursion.
2689
2690 Arguments:
2691   type         HMAC_MD5 or HMAC_SHA1
2692   remaining    are as for the cryptographic hash functions
2693
2694 Returns:       nothing
2695 */
2696
2697 static void
2698 chash_start(int type, void *base)
2699 {
2700 if (type == HMAC_MD5)
2701   md5_start((md5 *)base);
2702 else
2703   sha1_start((sha1 *)base);
2704 }
2705
2706 static void
2707 chash_mid(int type, void *base, uschar *string)
2708 {
2709 if (type == HMAC_MD5)
2710   md5_mid((md5 *)base, string);
2711 else
2712   sha1_mid((sha1 *)base, string);
2713 }
2714
2715 static void
2716 chash_end(int type, void *base, uschar *string, int length, uschar *digest)
2717 {
2718 if (type == HMAC_MD5)
2719   md5_end((md5 *)base, string, length, digest);
2720 else
2721   sha1_end((sha1 *)base, string, length, digest);
2722 }
2723
2724
2725
2726
2727
2728 /********************************************************
2729 * prvs: Get last three digits of days since Jan 1, 1970 *
2730 ********************************************************/
2731
2732 /* This is needed to implement the "prvs" BATV reverse
2733    path signing scheme
2734
2735 Argument: integer "days" offset to add or substract to
2736           or from the current number of days.
2737
2738 Returns:  pointer to string containing the last three
2739           digits of the number of days since Jan 1, 1970,
2740           modified by the offset argument, NULL if there
2741           was an error in the conversion.
2742
2743 */
2744
2745 static uschar *
2746 prvs_daystamp(int day_offset)
2747 {
2748 uschar *days = store_get(32);                /* Need at least 24 for cases */
2749 (void)string_format(days, 32, TIME_T_FMT,    /* where TIME_T_FMT is %lld */
2750   (time(NULL) + day_offset*86400)/86400);
2751 return (Ustrlen(days) >= 3) ? &days[Ustrlen(days)-3] : US"100";
2752 }
2753
2754
2755
2756 /********************************************************
2757 *   prvs: perform HMAC-SHA1 computation of prvs bits    *
2758 ********************************************************/
2759
2760 /* This is needed to implement the "prvs" BATV reverse
2761    path signing scheme
2762
2763 Arguments:
2764   address RFC2821 Address to use
2765       key The key to use (must be less than 64 characters
2766           in size)
2767   key_num Single-digit key number to use. Defaults to
2768           '0' when NULL.
2769
2770 Returns:  pointer to string containing the first three
2771           bytes of the final hash in hex format, NULL if
2772           there was an error in the process.
2773 */
2774
2775 static uschar *
2776 prvs_hmac_sha1(uschar *address, uschar *key, uschar *key_num, uschar *daystamp)
2777 {
2778 uschar *hash_source, *p;
2779 int size = 0,offset = 0,i;
2780 sha1 sha1_base;
2781 void *use_base = &sha1_base;
2782 uschar innerhash[20];
2783 uschar finalhash[20];
2784 uschar innerkey[64];
2785 uschar outerkey[64];
2786 uschar *finalhash_hex = store_get(40);
2787
2788 if (key_num == NULL)
2789   key_num = US"0";
2790
2791 if (Ustrlen(key) > 64)
2792   return NULL;
2793
2794 hash_source = string_cat(NULL,&size,&offset,key_num,1);
2795 string_cat(hash_source,&size,&offset,daystamp,3);
2796 string_cat(hash_source,&size,&offset,address,Ustrlen(address));
2797 hash_source[offset] = '\0';
2798
2799 DEBUG(D_expand) debug_printf("prvs: hash source is '%s'\n", hash_source);
2800
2801 memset(innerkey, 0x36, 64);
2802 memset(outerkey, 0x5c, 64);
2803
2804 for (i = 0; i < Ustrlen(key); i++)
2805   {
2806   innerkey[i] ^= key[i];
2807   outerkey[i] ^= key[i];
2808   }
2809
2810 chash_start(HMAC_SHA1, use_base);
2811 chash_mid(HMAC_SHA1, use_base, innerkey);
2812 chash_end(HMAC_SHA1, use_base, hash_source, offset, innerhash);
2813
2814 chash_start(HMAC_SHA1, use_base);
2815 chash_mid(HMAC_SHA1, use_base, outerkey);
2816 chash_end(HMAC_SHA1, use_base, innerhash, 20, finalhash);
2817
2818 p = finalhash_hex;
2819 for (i = 0; i < 3; i++)
2820   {
2821   *p++ = hex_digits[(finalhash[i] & 0xf0) >> 4];
2822   *p++ = hex_digits[finalhash[i] & 0x0f];
2823   }
2824 *p = '\0';
2825
2826 return finalhash_hex;
2827 }
2828
2829
2830
2831
2832 /*************************************************
2833 *        Join a file onto the output string      *
2834 *************************************************/
2835
2836 /* This is used for readfile and after a run expansion. It joins the contents
2837 of a file onto the output string, globally replacing newlines with a given
2838 string (optionally). The file is closed at the end.
2839
2840 Arguments:
2841   f            the FILE
2842   yield        pointer to the expandable string
2843   sizep        pointer to the current size
2844   ptrp         pointer to the current position
2845   eol          newline replacement string, or NULL
2846
2847 Returns:       new value of string pointer
2848 */
2849
2850 static uschar *
2851 cat_file(FILE *f, uschar *yield, int *sizep, int *ptrp, uschar *eol)
2852 {
2853 int eollen;
2854 uschar buffer[1024];
2855
2856 eollen = (eol == NULL)? 0 : Ustrlen(eol);
2857
2858 while (Ufgets(buffer, sizeof(buffer), f) != NULL)
2859   {
2860   int len = Ustrlen(buffer);
2861   if (eol != NULL && buffer[len-1] == '\n') len--;
2862   yield = string_cat(yield, sizep, ptrp, buffer, len);
2863   if (buffer[len] != 0)
2864     yield = string_cat(yield, sizep, ptrp, eol, eollen);
2865   }
2866
2867 if (yield != NULL) yield[*ptrp] = 0;
2868
2869 return yield;
2870 }
2871
2872
2873
2874
2875 /*************************************************
2876 *          Evaluate numeric expression           *
2877 *************************************************/
2878
2879 /* This is a set of mutually recursive functions that evaluate an arithmetic
2880 expression involving + - * / % & | ^ ~ << >> and parentheses. The only one of
2881 these functions that is called from elsewhere is eval_expr, whose interface is:
2882
2883 Arguments:
2884   sptr        pointer to the pointer to the string - gets updated
2885   decimal     TRUE if numbers are to be assumed decimal
2886   error       pointer to where to put an error message - must be NULL on input
2887   endket      TRUE if ')' must terminate - FALSE for external call
2888
2889 Returns:      on success: the value of the expression, with *error still NULL
2890               on failure: an undefined value, with *error = a message
2891 */
2892
2893 static int eval_op_or(uschar **, BOOL, uschar **);
2894
2895
2896 static int
2897 eval_expr(uschar **sptr, BOOL decimal, uschar **error, BOOL endket)
2898 {
2899 uschar *s = *sptr;
2900 int x = eval_op_or(&s, decimal, error);
2901 if (*error == NULL)
2902   {
2903   if (endket)
2904     {
2905     if (*s != ')')
2906       *error = US"expecting closing parenthesis";
2907     else
2908       while (isspace(*(++s)));
2909     }
2910   else if (*s != 0) *error = US"expecting operator";
2911   }
2912 *sptr = s;
2913 return x;
2914 }
2915
2916
2917 static int
2918 eval_number(uschar **sptr, BOOL decimal, uschar **error)
2919 {
2920 register int c;
2921 int n;
2922 uschar *s = *sptr;
2923 while (isspace(*s)) s++;
2924 c = *s;
2925 if (isdigit(c))
2926   {
2927   int count;
2928   (void)sscanf(CS s, (decimal? "%d%n" : "%i%n"), &n, &count);
2929   s += count;
2930   if (tolower(*s) == 'k') { n *= 1024; s++; }
2931     else if (tolower(*s) == 'm') { n *= 1024*1024; s++; }
2932   while (isspace (*s)) s++;
2933   }
2934 else if (c == '(')
2935   {
2936   s++;
2937   n = eval_expr(&s, decimal, error, 1);
2938   }
2939 else
2940   {
2941   *error = US"expecting number or opening parenthesis";
2942   n = 0;
2943   }
2944 *sptr = s;
2945 return n;
2946 }
2947
2948
2949 static int eval_op_unary(uschar **sptr, BOOL decimal, uschar **error)
2950 {
2951 uschar *s = *sptr;
2952 int x;
2953 while (isspace(*s)) s++;
2954 if (*s == '+' || *s == '-' || *s == '~')
2955   {
2956   int op = *s++;
2957   x = eval_op_unary(&s, decimal, error);
2958   if (op == '-') x = -x;
2959     else if (op == '~') x = ~x;
2960   }
2961 else
2962   {
2963   x = eval_number(&s, decimal, error);
2964   }
2965 *sptr = s;
2966 return x;
2967 }
2968
2969
2970 static int eval_op_mult(uschar **sptr, BOOL decimal, uschar **error)
2971 {
2972 uschar *s = *sptr;
2973 int x = eval_op_unary(&s, decimal, error);
2974 if (*error == NULL)
2975   {
2976   while (*s == '*' || *s == '/' || *s == '%')
2977     {
2978     int op = *s++;
2979     int y = eval_op_unary(&s, decimal, error);
2980     if (*error != NULL) break;
2981     if (op == '*') x *= y;
2982       else if (op == '/') x /= y;
2983       else x %= y;
2984     }
2985   }
2986 *sptr = s;
2987 return x;
2988 }
2989
2990
2991 static int eval_op_sum(uschar **sptr, BOOL decimal, uschar **error)
2992 {
2993 uschar *s = *sptr;
2994 int x = eval_op_mult(&s, decimal, error);
2995 if (*error == NULL)
2996   {
2997   while (*s == '+' || *s == '-')
2998     {
2999     int op = *s++;
3000     int y = eval_op_mult(&s, decimal, error);
3001     if (*error != NULL) break;
3002     if (op == '+') x += y; else x -= y;
3003     }
3004   }
3005 *sptr = s;
3006 return x;
3007 }
3008
3009
3010 static int eval_op_shift(uschar **sptr, BOOL decimal, uschar **error)
3011 {
3012 uschar *s = *sptr;
3013 int x = eval_op_sum(&s, decimal, error);
3014 if (*error == NULL)
3015   {
3016   while ((*s == '<' || *s == '>') && s[1] == s[0])
3017     {
3018     int y;
3019     int op = *s++;
3020     s++;
3021     y = eval_op_sum(&s, decimal, error);
3022     if (*error != NULL) break;
3023     if (op == '<') x <<= y; else x >>= y;
3024     }
3025   }
3026 *sptr = s;
3027 return x;
3028 }
3029
3030
3031 static int eval_op_and(uschar **sptr, BOOL decimal, uschar **error)
3032 {
3033 uschar *s = *sptr;
3034 int x = eval_op_shift(&s, decimal, error);
3035 if (*error == NULL)
3036   {
3037   while (*s == '&')
3038     {
3039     int y;
3040     s++;
3041     y = eval_op_shift(&s, decimal, error);
3042     if (*error != NULL) break;
3043     x &= y;
3044     }
3045   }
3046 *sptr = s;
3047 return x;
3048 }
3049
3050
3051 static int eval_op_xor(uschar **sptr, BOOL decimal, uschar **error)
3052 {
3053 uschar *s = *sptr;
3054 int x = eval_op_and(&s, decimal, error);
3055 if (*error == NULL)
3056   {
3057   while (*s == '^')
3058     {
3059     int y;
3060     s++;
3061     y = eval_op_and(&s, decimal, error);
3062     if (*error != NULL) break;
3063     x ^= y;
3064     }
3065   }
3066 *sptr = s;
3067 return x;
3068 }
3069
3070
3071 static int eval_op_or(uschar **sptr, BOOL decimal, uschar **error)
3072 {
3073 uschar *s = *sptr;
3074 int x = eval_op_xor(&s, decimal, error);
3075 if (*error == NULL)
3076   {
3077   while (*s == '|')
3078     {
3079     int y;
3080     s++;
3081     y = eval_op_xor(&s, decimal, error);
3082     if (*error != NULL) break;
3083     x |= y;
3084     }
3085   }
3086 *sptr = s;
3087 return x;
3088 }
3089
3090
3091
3092 /*************************************************
3093 *                 Expand string                  *
3094 *************************************************/
3095
3096 /* Returns either an unchanged string, or the expanded string in stacking pool
3097 store. Interpreted sequences are:
3098
3099    \...                    normal escaping rules
3100    $name                   substitutes the variable
3101    ${name}                 ditto
3102    ${op:string}            operates on the expanded string value
3103    ${item{arg1}{arg2}...}  expands the args and then does the business
3104                              some literal args are not enclosed in {}
3105
3106 There are now far too many operators and item types to make it worth listing
3107 them here in detail any more.
3108
3109 We use an internal routine recursively to handle embedded substrings. The
3110 external function follows. The yield is NULL if the expansion failed, and there
3111 are two cases: if something collapsed syntactically, or if "fail" was given
3112 as the action on a lookup failure. These can be distinguised by looking at the
3113 variable expand_string_forcedfail, which is TRUE in the latter case.
3114
3115 The skipping flag is set true when expanding a substring that isn't actually
3116 going to be used (after "if" or "lookup") and it prevents lookups from
3117 happening lower down.
3118
3119 Store usage: At start, a store block of the length of the input plus 64
3120 is obtained. This is expanded as necessary by string_cat(), which might have to
3121 get a new block, or might be able to expand the original. At the end of the
3122 function we can release any store above that portion of the yield block that
3123 was actually used. In many cases this will be optimal.
3124
3125 However: if the first item in the expansion is a variable name or header name,
3126 we reset the store before processing it; if the result is in fresh store, we
3127 use that without copying. This is helpful for expanding strings like
3128 $message_headers which can get very long.
3129
3130 Arguments:
3131   string         the string to be expanded
3132   ket_ends       true if expansion is to stop at }
3133   left           if not NULL, a pointer to the first character after the
3134                  expansion is placed here (typically used with ket_ends)
3135   skipping       TRUE for recursive calls when the value isn't actually going
3136                  to be used (to allow for optimisation)
3137
3138 Returns:         NULL if expansion fails:
3139                    expand_string_forcedfail is set TRUE if failure was forced
3140                    expand_string_message contains a textual error message
3141                  a pointer to the expanded string on success
3142 */
3143
3144 static uschar *
3145 expand_string_internal(uschar *string, BOOL ket_ends, uschar **left,
3146   BOOL skipping)
3147 {
3148 int ptr = 0;
3149 int size = Ustrlen(string)+ 64;
3150 int item_type;
3151 uschar *yield = store_get(size);
3152 uschar *s = string;
3153 uschar *save_expand_nstring[EXPAND_MAXN+1];
3154 int save_expand_nlength[EXPAND_MAXN+1];
3155
3156 expand_string_forcedfail = FALSE;
3157 expand_string_message = US"";
3158
3159 while (*s != 0)
3160   {
3161   uschar *value;
3162   uschar name[256];
3163
3164   /* \ escapes the next character, which must exist, or else
3165   the expansion fails. There's a special escape, \N, which causes
3166   copying of the subject verbatim up to the next \N. Otherwise,
3167   the escapes are the standard set. */
3168
3169   if (*s == '\\')
3170     {
3171     if (s[1] == 0)
3172       {
3173       expand_string_message = US"\\ at end of string";
3174       goto EXPAND_FAILED;
3175       }
3176
3177     if (s[1] == 'N')
3178       {
3179       uschar *t = s + 2;
3180       for (s = t; *s != 0; s++) if (*s == '\\' && s[1] == 'N') break;
3181       yield = string_cat(yield, &size, &ptr, t, s - t);
3182       if (*s != 0) s += 2;
3183       }
3184
3185     else
3186       {
3187       uschar ch[1];
3188       ch[0] = string_interpret_escape(&s);
3189       s++;
3190       yield = string_cat(yield, &size, &ptr, ch, 1);
3191       }
3192
3193     continue;
3194     }
3195
3196   /* Anything other than $ is just copied verbatim, unless we are
3197   looking for a terminating } character. */
3198
3199   if (ket_ends && *s == '}') break;
3200
3201   if (*s != '$')
3202     {
3203     yield = string_cat(yield, &size, &ptr, s++, 1);
3204     continue;
3205     }
3206
3207   /* No { after the $ - must be a plain name or a number for string
3208   match variable. There has to be a fudge for variables that are the
3209   names of header fields preceded by "$header_" because header field
3210   names can contain any printing characters except space and colon.
3211   For those that don't like typing this much, "$h_" is a synonym for
3212   "$header_". A non-existent header yields a NULL value; nothing is
3213   inserted. */
3214
3215   if (isalpha((*(++s))))
3216     {
3217     int len;
3218     int newsize = 0;
3219
3220     s = read_name(name, sizeof(name), s, US"_");
3221
3222     /* If this is the first thing to be expanded, release the pre-allocated
3223     buffer. */
3224
3225     if (ptr == 0 && yield != NULL)
3226       {
3227       store_reset(yield);
3228       yield = NULL;
3229       size = 0;
3230       }
3231
3232     /* Header */
3233
3234     if (Ustrncmp(name, "h_", 2) == 0 ||
3235         Ustrncmp(name, "rh_", 3) == 0 ||
3236         Ustrncmp(name, "bh_", 3) == 0 ||
3237         Ustrncmp(name, "header_", 7) == 0 ||
3238         Ustrncmp(name, "rheader_", 8) == 0 ||
3239         Ustrncmp(name, "bheader_", 8) == 0)
3240       {
3241       BOOL want_raw = (name[0] == 'r')? TRUE : FALSE;
3242       uschar *charset = (name[0] == 'b')? NULL : headers_charset;
3243       s = read_header_name(name, sizeof(name), s);
3244       value = find_header(name, FALSE, &newsize, want_raw, charset);
3245
3246       /* If we didn't find the header, and the header contains a closing brace
3247       character, this may be a user error where the terminating colon
3248       has been omitted. Set a flag to adjust the error message in this case.
3249       But there is no error here - nothing gets inserted. */
3250
3251       if (value == NULL)
3252         {
3253         if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
3254         continue;
3255         }
3256       }
3257
3258     /* Variable */
3259
3260     else
3261       {
3262       value = find_variable(name, FALSE, skipping, &newsize);
3263       if (value == NULL)
3264         {
3265         expand_string_message =
3266           string_sprintf("unknown variable name \"%s\"", name);
3267           check_variable_error_message(name);
3268         goto EXPAND_FAILED;
3269         }
3270       }
3271
3272     /* If the data is known to be in a new buffer, newsize will be set to the
3273     size of that buffer. If this is the first thing in an expansion string,
3274     yield will be NULL; just point it at the new store instead of copying. Many
3275     expansion strings contain just one reference, so this is a useful
3276     optimization, especially for humungous headers. */
3277
3278     len = Ustrlen(value);
3279     if (yield == NULL && newsize != 0)
3280       {
3281       yield = value;
3282       size = newsize;
3283       ptr = len;
3284       }
3285     else yield = string_cat(yield, &size, &ptr, value, len);
3286
3287     continue;
3288     }
3289
3290   if (isdigit(*s))
3291     {
3292     int n;
3293     s = read_number(&n, s);
3294     if (n >= 0 && n <= expand_nmax)
3295       yield = string_cat(yield, &size, &ptr, expand_nstring[n],
3296         expand_nlength[n]);
3297     continue;
3298     }
3299
3300   /* Otherwise, if there's no '{' after $ it's an error. */
3301
3302   if (*s != '{')
3303     {
3304     expand_string_message = US"$ not followed by letter, digit, or {";
3305     goto EXPAND_FAILED;
3306     }
3307
3308   /* After { there can be various things, but they all start with
3309   an initial word, except for a number for a string match variable. */
3310
3311   if (isdigit((*(++s))))
3312     {
3313     int n;
3314     s = read_number(&n, s);
3315     if (*s++ != '}')
3316       {
3317       expand_string_message = US"} expected after number";
3318       goto EXPAND_FAILED;
3319       }
3320     if (n >= 0 && n <= expand_nmax)
3321       yield = string_cat(yield, &size, &ptr, expand_nstring[n],
3322         expand_nlength[n]);
3323     continue;
3324     }
3325
3326   if (!isalpha(*s))
3327     {
3328     expand_string_message = US"letter or digit expected after ${";
3329     goto EXPAND_FAILED;
3330     }
3331
3332   /* Allow "-" in names to cater for substrings with negative
3333   arguments. Since we are checking for known names after { this is
3334   OK. */
3335
3336   s = read_name(name, sizeof(name), s, US"_-");
3337   item_type = chop_match(name, item_table, sizeof(item_table)/sizeof(uschar *));
3338
3339   switch(item_type)
3340     {
3341     /* Handle conditionals - preserve the values of the numerical expansion
3342     variables in case they get changed by a regular expression match in the
3343     condition. If not, they retain their external settings. At the end
3344     of this "if" section, they get restored to their previous values. */
3345
3346     case EITEM_IF:
3347       {
3348       BOOL cond = FALSE;
3349       uschar *next_s;
3350       int save_expand_nmax =
3351         save_expand_strings(save_expand_nstring, save_expand_nlength);
3352
3353       while (isspace(*s)) s++;
3354       next_s = eval_condition(s, skipping? NULL : &cond);
3355       if (next_s == NULL) goto EXPAND_FAILED;  /* message already set */
3356
3357       DEBUG(D_expand)
3358         debug_printf("condition: %.*s\n   result: %s\n", (int)(next_s - s), s,
3359           cond? "true" : "false");
3360
3361       s = next_s;
3362
3363       /* The handling of "yes" and "no" result strings is now in a separate
3364       function that is also used by ${lookup} and ${extract} and ${run}. */
3365
3366       switch(process_yesno(
3367                skipping,                     /* were previously skipping */
3368                cond,                         /* success/failure indicator */
3369                lookup_value,                 /* value to reset for string2 */
3370                &s,                           /* input pointer */
3371                &yield,                       /* output pointer */
3372                &size,                        /* output size */
3373                &ptr,                         /* output current point */
3374                US"if"))                      /* condition type */
3375         {
3376         case 1: goto EXPAND_FAILED;          /* when all is well, the */
3377         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
3378         }
3379
3380       /* Restore external setting of expansion variables for continuation
3381       at this level. */
3382
3383       restore_expand_strings(save_expand_nmax, save_expand_nstring,
3384         save_expand_nlength);
3385       continue;
3386       }
3387
3388     /* Handle database lookups unless locked out. If "skipping" is TRUE, we are
3389     expanding an internal string that isn't actually going to be used. All we
3390     need to do is check the syntax, so don't do a lookup at all. Preserve the
3391     values of the numerical expansion variables in case they get changed by a
3392     partial lookup. If not, they retain their external settings. At the end
3393     of this "lookup" section, they get restored to their previous values. */
3394
3395     case EITEM_LOOKUP:
3396       {
3397       int stype, partial, affixlen, starflags;
3398       int expand_setup = 0;
3399       int nameptr = 0;
3400       uschar *key, *filename, *affix;
3401       uschar *save_lookup_value = lookup_value;
3402       int save_expand_nmax =
3403         save_expand_strings(save_expand_nstring, save_expand_nlength);
3404
3405       if ((expand_forbid & RDO_LOOKUP) != 0)
3406         {
3407         expand_string_message = US"lookup expansions are not permitted";
3408         goto EXPAND_FAILED;
3409         }
3410
3411       /* Get the key we are to look up for single-key+file style lookups.
3412       Otherwise set the key NULL pro-tem. */
3413
3414       while (isspace(*s)) s++;
3415       if (*s == '{')
3416         {
3417         key = expand_string_internal(s+1, TRUE, &s, skipping);
3418         if (key == NULL) goto EXPAND_FAILED;
3419         if (*s++ != '}') goto EXPAND_FAILED_CURLY;
3420         while (isspace(*s)) s++;
3421         }
3422       else key = NULL;
3423
3424       /* Find out the type of database */
3425
3426       if (!isalpha(*s))
3427         {
3428         expand_string_message = US"missing lookup type";
3429         goto EXPAND_FAILED;
3430         }
3431
3432       /* The type is a string that may contain special characters of various
3433       kinds. Allow everything except space or { to appear; the actual content
3434       is checked by search_findtype_partial. */
3435
3436       while (*s != 0 && *s != '{' && !isspace(*s))
3437         {
3438         if (nameptr < sizeof(name) - 1) name[nameptr++] = *s;
3439         s++;
3440         }
3441       name[nameptr] = 0;
3442       while (isspace(*s)) s++;
3443
3444       /* Now check for the individual search type and any partial or default
3445       options. Only those types that are actually in the binary are valid. */
3446
3447       stype = search_findtype_partial(name, &partial, &affix, &affixlen,
3448         &starflags);
3449       if (stype < 0)
3450         {
3451         expand_string_message = search_error_message;
3452         goto EXPAND_FAILED;
3453         }
3454
3455       /* Check that a key was provided for those lookup types that need it,
3456       and was not supplied for those that use the query style. */
3457
3458       if (!mac_islookup(stype, lookup_querystyle|lookup_absfilequery))
3459         {
3460         if (key == NULL)
3461           {
3462           expand_string_message = string_sprintf("missing {key} for single-"
3463             "key \"%s\" lookup", name);
3464           goto EXPAND_FAILED;
3465           }
3466         }
3467       else
3468         {
3469         if (key != NULL)
3470           {
3471           expand_string_message = string_sprintf("a single key was given for "
3472             "lookup type \"%s\", which is not a single-key lookup type", name);
3473           goto EXPAND_FAILED;
3474           }
3475         }
3476
3477       /* Get the next string in brackets and expand it. It is the file name for
3478       single-key+file lookups, and the whole query otherwise. In the case of
3479       queries that also require a file name (e.g. sqlite), the file name comes
3480       first. */
3481
3482       if (*s != '{') goto EXPAND_FAILED_CURLY;
3483       filename = expand_string_internal(s+1, TRUE, &s, skipping);
3484       if (filename == NULL) goto EXPAND_FAILED;
3485       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
3486       while (isspace(*s)) s++;
3487
3488       /* If this isn't a single-key+file lookup, re-arrange the variables
3489       to be appropriate for the search_ functions. For query-style lookups,
3490       there is just a "key", and no file name. For the special query-style +
3491       file types, the query (i.e. "key") starts with a file name. */
3492
3493       if (key == NULL)
3494         {
3495         while (isspace(*filename)) filename++;
3496         key = filename;
3497
3498         if (mac_islookup(stype, lookup_querystyle))
3499           {
3500           filename = NULL;
3501           }
3502         else
3503           {
3504           if (*filename != '/')
3505             {
3506             expand_string_message = string_sprintf(
3507               "absolute file name expected for \"%s\" lookup", name);
3508             goto EXPAND_FAILED;
3509             }
3510           while (*key != 0 && !isspace(*key)) key++;
3511           if (*key != 0) *key++ = 0;
3512           }
3513         }
3514
3515       /* If skipping, don't do the next bit - just lookup_value == NULL, as if
3516       the entry was not found. Note that there is no search_close() function.
3517       Files are left open in case of re-use. At suitable places in higher logic,
3518       search_tidyup() is called to tidy all open files. This can save opening
3519       the same file several times. However, files may also get closed when
3520       others are opened, if too many are open at once. The rule is that a
3521       handle should not be used after a second search_open().
3522
3523       Request that a partial search sets up $1 and maybe $2 by passing
3524       expand_setup containing zero. If its value changes, reset expand_nmax,
3525       since new variables will have been set. Note that at the end of this
3526       "lookup" section, the old numeric variables are restored. */
3527
3528       if (skipping)
3529         lookup_value = NULL;
3530       else
3531         {
3532         void *handle = search_open(filename, stype, 0, NULL, NULL);
3533         if (handle == NULL)
3534           {
3535           expand_string_message = search_error_message;
3536           goto EXPAND_FAILED;
3537           }
3538         lookup_value = search_find(handle, filename, key, partial, affix,
3539           affixlen, starflags, &expand_setup);
3540         if (search_find_defer)
3541           {
3542           expand_string_message =
3543             string_sprintf("lookup of \"%s\" gave DEFER: %s", key,
3544               search_error_message);
3545           goto EXPAND_FAILED;
3546           }
3547         if (expand_setup > 0) expand_nmax = expand_setup;
3548         }
3549
3550       /* The handling of "yes" and "no" result strings is now in a separate
3551       function that is also used by ${if} and ${extract}. */
3552
3553       switch(process_yesno(
3554                skipping,                     /* were previously skipping */
3555                lookup_value != NULL,         /* success/failure indicator */
3556                save_lookup_value,            /* value to reset for string2 */
3557                &s,                           /* input pointer */
3558                &yield,                       /* output pointer */
3559                &size,                        /* output size */
3560                &ptr,                         /* output current point */
3561                US"lookup"))                  /* condition type */
3562         {
3563         case 1: goto EXPAND_FAILED;          /* when all is well, the */
3564         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
3565         }
3566
3567       /* Restore external setting of expansion variables for carrying on
3568       at this level, and continue. */
3569
3570       restore_expand_strings(save_expand_nmax, save_expand_nstring,
3571         save_expand_nlength);
3572       continue;
3573       }
3574
3575     /* If Perl support is configured, handle calling embedded perl subroutines,
3576     unless locked out at this time. Syntax is ${perl{sub}} or ${perl{sub}{arg}}
3577     or ${perl{sub}{arg1}{arg2}} or up to a maximum of EXIM_PERL_MAX_ARGS
3578     arguments (defined below). */
3579
3580     #define EXIM_PERL_MAX_ARGS 8
3581
3582     case EITEM_PERL:
3583     #ifndef EXIM_PERL
3584     expand_string_message = US"\"${perl\" encountered, but this facility "
3585       "is not included in this binary";
3586     goto EXPAND_FAILED;
3587
3588     #else   /* EXIM_PERL */
3589       {
3590       uschar *sub_arg[EXIM_PERL_MAX_ARGS + 2];
3591       uschar *new_yield;
3592
3593       if ((expand_forbid & RDO_PERL) != 0)
3594         {
3595         expand_string_message = US"Perl calls are not permitted";
3596         goto EXPAND_FAILED;
3597         }
3598
3599       switch(read_subs(sub_arg, EXIM_PERL_MAX_ARGS + 1, 1, &s, skipping, TRUE,
3600            US"perl"))
3601         {
3602         case 1: goto EXPAND_FAILED_CURLY;
3603         case 2:
3604         case 3: goto EXPAND_FAILED;
3605         }
3606
3607       /* If skipping, we don't actually do anything */
3608
3609       if (skipping) continue;
3610
3611       /* Start the interpreter if necessary */
3612
3613       if (!opt_perl_started)
3614         {
3615         uschar *initerror;
3616         if (opt_perl_startup == NULL)
3617           {
3618           expand_string_message = US"A setting of perl_startup is needed when "
3619             "using the Perl interpreter";
3620           goto EXPAND_FAILED;
3621           }
3622         DEBUG(D_any) debug_printf("Starting Perl interpreter\n");
3623         initerror = init_perl(opt_perl_startup);
3624         if (initerror != NULL)
3625           {
3626           expand_string_message =
3627             string_sprintf("error in perl_startup code: %s\n", initerror);
3628           goto EXPAND_FAILED;
3629           }
3630         opt_perl_started = TRUE;
3631         }
3632
3633       /* Call the function */
3634
3635       sub_arg[EXIM_PERL_MAX_ARGS + 1] = NULL;
3636       new_yield = call_perl_cat(yield, &size, &ptr, &expand_string_message,
3637         sub_arg[0], sub_arg + 1);
3638
3639       /* NULL yield indicates failure; if the message pointer has been set to
3640       NULL, the yield was undef, indicating a forced failure. Otherwise the
3641       message will indicate some kind of Perl error. */
3642
3643       if (new_yield == NULL)
3644         {
3645         if (expand_string_message == NULL)
3646           {
3647           expand_string_message =
3648             string_sprintf("Perl subroutine \"%s\" returned undef to force "
3649               "failure", sub_arg[0]);
3650           expand_string_forcedfail = TRUE;
3651           }
3652         goto EXPAND_FAILED;
3653         }
3654
3655       /* Yield succeeded. Ensure forcedfail is unset, just in case it got
3656       set during a callback from Perl. */
3657
3658       expand_string_forcedfail = FALSE;
3659       yield = new_yield;
3660       continue;
3661       }
3662     #endif /* EXIM_PERL */
3663
3664     /* Transform email address to "prvs" scheme to use
3665        as BATV-signed return path */
3666
3667     case EITEM_PRVS:
3668       {
3669       uschar *sub_arg[3];
3670       uschar *p,*domain;
3671
3672       switch(read_subs(sub_arg, 3, 2, &s, skipping, TRUE, US"prvs"))
3673         {
3674         case 1: goto EXPAND_FAILED_CURLY;
3675         case 2:
3676         case 3: goto EXPAND_FAILED;
3677         }
3678
3679       /* If skipping, we don't actually do anything */
3680       if (skipping) continue;
3681
3682       /* sub_arg[0] is the address */
3683       domain = Ustrrchr(sub_arg[0],'@');
3684       if ( (domain == NULL) || (domain == sub_arg[0]) || (Ustrlen(domain) == 1) )
3685         {
3686         expand_string_message = US"prvs first argument must be a qualified email address";
3687         goto EXPAND_FAILED;
3688         }
3689
3690       /* Calculate the hash. The second argument must be a single-digit
3691       key number, or unset. */
3692
3693       if (sub_arg[2] != NULL &&
3694           (!isdigit(sub_arg[2][0]) || sub_arg[2][1] != 0))
3695         {
3696         expand_string_message = US"prvs second argument must be a single digit";
3697         goto EXPAND_FAILED;
3698         }
3699
3700       p = prvs_hmac_sha1(sub_arg[0],sub_arg[1],sub_arg[2],prvs_daystamp(7));
3701       if (p == NULL)
3702         {
3703         expand_string_message = US"prvs hmac-sha1 conversion failed";
3704         goto EXPAND_FAILED;
3705         }
3706
3707       /* Now separate the domain from the local part */
3708       *domain++ = '\0';
3709
3710       yield = string_cat(yield,&size,&ptr,US"prvs=",5);
3711       string_cat(yield,&size,&ptr,(sub_arg[2] != NULL) ? sub_arg[2] : US"0", 1);
3712       string_cat(yield,&size,&ptr,prvs_daystamp(7),3);
3713       string_cat(yield,&size,&ptr,p,6);
3714       string_cat(yield,&size,&ptr,US"=",1);
3715       string_cat(yield,&size,&ptr,sub_arg[0],Ustrlen(sub_arg[0]));
3716       string_cat(yield,&size,&ptr,US"@",1);
3717       string_cat(yield,&size,&ptr,domain,Ustrlen(domain));
3718
3719       continue;
3720       }
3721
3722     /* Check a prvs-encoded address for validity */
3723
3724     case EITEM_PRVSCHECK:
3725       {
3726       uschar *sub_arg[3];
3727       int mysize = 0, myptr = 0;
3728       const pcre *re;
3729       uschar *p;
3730
3731       /* TF: Ugliness: We want to expand parameter 1 first, then set
3732          up expansion variables that are used in the expansion of
3733          parameter 2. So we clone the string for the first
3734          expansion, where we only expand parameter 1.
3735
3736          PH: Actually, that isn't necessary. The read_subs() function is
3737          designed to work this way for the ${if and ${lookup expansions. I've
3738          tidied the code.
3739       */
3740
3741       /* Reset expansion variables */
3742       prvscheck_result = NULL;
3743       prvscheck_address = NULL;
3744       prvscheck_keynum = NULL;
3745
3746       switch(read_subs(sub_arg, 1, 1, &s, skipping, FALSE, US"prvs"))
3747         {
3748         case 1: goto EXPAND_FAILED_CURLY;
3749         case 2:
3750         case 3: goto EXPAND_FAILED;
3751         }
3752
3753       re = regex_must_compile(US"^prvs\\=([0-9])([0-9]{3})([A-F0-9]{6})\\=(.+)\\@(.+)$",
3754                               TRUE,FALSE);
3755
3756       if (regex_match_and_setup(re,sub_arg[0],0,-1))
3757         {
3758         uschar *local_part = string_copyn(expand_nstring[4],expand_nlength[4]);
3759         uschar *key_num = string_copyn(expand_nstring[1],expand_nlength[1]);
3760         uschar *daystamp = string_copyn(expand_nstring[2],expand_nlength[2]);
3761         uschar *hash = string_copyn(expand_nstring[3],expand_nlength[3]);
3762         uschar *domain = string_copyn(expand_nstring[5],expand_nlength[5]);
3763
3764         DEBUG(D_expand) debug_printf("prvscheck localpart: %s\n", local_part);
3765         DEBUG(D_expand) debug_printf("prvscheck key number: %s\n", key_num);
3766         DEBUG(D_expand) debug_printf("prvscheck daystamp: %s\n", daystamp);
3767         DEBUG(D_expand) debug_printf("prvscheck hash: %s\n", hash);
3768         DEBUG(D_expand) debug_printf("prvscheck domain: %s\n", domain);
3769
3770         /* Set up expansion variables */
3771         prvscheck_address = string_cat(NULL, &mysize, &myptr, local_part, Ustrlen(local_part));
3772         string_cat(prvscheck_address,&mysize,&myptr,US"@",1);
3773         string_cat(prvscheck_address,&mysize,&myptr,domain,Ustrlen(domain));
3774         prvscheck_address[myptr] = '\0';
3775         prvscheck_keynum = string_copy(key_num);
3776
3777         /* Now expand the second argument */
3778         switch(read_subs(sub_arg, 1, 1, &s, skipping, FALSE, US"prvs"))
3779           {
3780           case 1: goto EXPAND_FAILED_CURLY;
3781           case 2:
3782           case 3: goto EXPAND_FAILED;
3783           }
3784
3785         /* Now we have the key and can check the address. */
3786
3787         p = prvs_hmac_sha1(prvscheck_address, sub_arg[0], prvscheck_keynum,
3788           daystamp);
3789
3790         if (p == NULL)
3791           {
3792           expand_string_message = US"hmac-sha1 conversion failed";
3793           goto EXPAND_FAILED;
3794           }
3795
3796         DEBUG(D_expand) debug_printf("prvscheck: received hash is %s\n", hash);
3797         DEBUG(D_expand) debug_printf("prvscheck:      own hash is %s\n", p);
3798
3799         if (Ustrcmp(p,hash) == 0)
3800           {
3801           /* Success, valid BATV address. Now check the expiry date. */
3802           uschar *now = prvs_daystamp(0);
3803           unsigned int inow = 0,iexpire = 1;
3804
3805           (void)sscanf(CS now,"%u",&inow);
3806           (void)sscanf(CS daystamp,"%u",&iexpire);
3807
3808           /* When "iexpire" is < 7, a "flip" has occured.
3809              Adjust "inow" accordingly. */
3810           if ( (iexpire < 7) && (inow >= 993) ) inow = 0;
3811
3812           if (iexpire > inow)
3813             {
3814             prvscheck_result = US"1";
3815             DEBUG(D_expand) debug_printf("prvscheck: success, $pvrs_result set to 1\n");
3816             }
3817             else
3818             {
3819             prvscheck_result = NULL;
3820             DEBUG(D_expand) debug_printf("prvscheck: signature expired, $pvrs_result unset\n");
3821             }
3822           }
3823         else
3824           {
3825           prvscheck_result = NULL;
3826           DEBUG(D_expand) debug_printf("prvscheck: hash failure, $pvrs_result unset\n");
3827           }
3828
3829         /* Now expand the final argument. We leave this till now so that
3830         it can include $prvscheck_result. */
3831
3832         switch(read_subs(sub_arg, 1, 0, &s, skipping, TRUE, US"prvs"))
3833           {
3834           case 1: goto EXPAND_FAILED_CURLY;
3835           case 2:
3836           case 3: goto EXPAND_FAILED;
3837           }
3838
3839         if (sub_arg[0] == NULL || *sub_arg[0] == '\0')
3840           yield = string_cat(yield,&size,&ptr,prvscheck_address,Ustrlen(prvscheck_address));
3841         else
3842           yield = string_cat(yield,&size,&ptr,sub_arg[0],Ustrlen(sub_arg[0]));
3843
3844         /* Reset the "internal" variables afterwards, because they are in
3845         dynamic store that will be reclaimed if the expansion succeeded. */
3846
3847         prvscheck_address = NULL;
3848         prvscheck_keynum = NULL;
3849         }
3850       else
3851         {
3852         /* Does not look like a prvs encoded address, return the empty string.
3853            We need to make sure all subs are expanded first, so as to skip over
3854            the entire item. */
3855
3856         switch(read_subs(sub_arg, 2, 1, &s, skipping, TRUE, US"prvs"))
3857           {
3858           case 1: goto EXPAND_FAILED_CURLY;
3859           case 2:
3860           case 3: goto EXPAND_FAILED;
3861           }
3862         }
3863
3864       continue;
3865       }
3866
3867     /* Handle "readfile" to insert an entire file */
3868
3869     case EITEM_READFILE:
3870       {
3871       FILE *f;
3872       uschar *sub_arg[2];
3873
3874       if ((expand_forbid & RDO_READFILE) != 0)
3875         {
3876         expand_string_message = US"file insertions are not permitted";
3877         goto EXPAND_FAILED;
3878         }
3879
3880       switch(read_subs(sub_arg, 2, 1, &s, skipping, TRUE, US"readfile"))
3881         {
3882         case 1: goto EXPAND_FAILED_CURLY;
3883         case 2:
3884         case 3: goto EXPAND_FAILED;
3885         }
3886
3887       /* If skipping, we don't actually do anything */
3888
3889       if (skipping) continue;
3890
3891       /* Open the file and read it */
3892
3893       f = Ufopen(sub_arg[0], "rb");
3894       if (f == NULL)
3895         {
3896         expand_string_message = string_open_failed(errno, "%s", sub_arg[0]);
3897         goto EXPAND_FAILED;
3898         }
3899
3900       yield = cat_file(f, yield, &size, &ptr, sub_arg[1]);
3901       (void)fclose(f);
3902       continue;
3903       }
3904
3905     /* Handle "readsocket" to insert data from a Unix domain socket */
3906
3907     case EITEM_READSOCK:
3908       {
3909       int fd;
3910       int timeout = 5;
3911       int save_ptr = ptr;
3912       FILE *f;
3913       struct sockaddr_un sockun;         /* don't call this "sun" ! */
3914       uschar *arg;
3915       uschar *sub_arg[4];
3916
3917       if ((expand_forbid & RDO_READSOCK) != 0)
3918         {
3919         expand_string_message = US"socket insertions are not permitted";
3920         goto EXPAND_FAILED;
3921         }
3922
3923       /* Read up to 4 arguments, but don't do the end of item check afterwards,
3924       because there may be a string for expansion on failure. */
3925
3926       switch(read_subs(sub_arg, 4, 2, &s, skipping, FALSE, US"readsocket"))
3927         {
3928         case 1: goto EXPAND_FAILED_CURLY;
3929         case 2:                             /* Won't occur: no end check */
3930         case 3: goto EXPAND_FAILED;
3931         }
3932
3933       /* Sort out timeout, if given */
3934
3935       if (sub_arg[2] != NULL)
3936         {
3937         timeout = readconf_readtime(sub_arg[2], 0, FALSE);
3938         if (timeout < 0)
3939           {
3940           expand_string_message = string_sprintf("bad time value %s",
3941             sub_arg[2]);
3942           goto EXPAND_FAILED;
3943           }
3944         }
3945       else sub_arg[3] = NULL;                     /* No eol if no timeout */
3946
3947       /* If skipping, we don't actually do anything. Otherwise, arrange to
3948       connect to either an IP or a Unix socket. */
3949
3950       if (!skipping)
3951         {
3952         /* Handle an IP (internet) domain */
3953
3954         if (Ustrncmp(sub_arg[0], "inet:", 5) == 0)
3955           {
3956           BOOL connected = FALSE;
3957           int namelen, port;
3958           host_item shost;
3959           host_item *h;
3960           uschar *server_name = sub_arg[0] + 5;
3961           uschar *port_name = Ustrrchr(server_name, ':');
3962
3963           /* Sort out the port */
3964
3965           if (port_name == NULL)
3966             {
3967             expand_string_message =
3968               string_sprintf("missing port for readsocket %s", sub_arg[0]);
3969             goto EXPAND_FAILED;
3970             }
3971           *port_name++ = 0;           /* Terminate server name */
3972
3973           if (isdigit(*port_name))
3974             {
3975             uschar *end;
3976             port = Ustrtol(port_name, &end, 0);
3977             if (end != port_name + Ustrlen(port_name))
3978               {
3979               expand_string_message =
3980                 string_sprintf("invalid port number %s", port_name);
3981               goto EXPAND_FAILED;
3982               }
3983             }
3984           else
3985             {
3986             struct servent *service_info = getservbyname(CS port_name, "tcp");
3987             if (service_info == NULL)
3988               {
3989               expand_string_message = string_sprintf("unknown port \"%s\"",
3990                 port_name);
3991               goto EXPAND_FAILED;
3992               }
3993             port = ntohs(service_info->s_port);
3994             }
3995
3996           /* Sort out the server. */
3997
3998           shost.next = NULL;
3999           shost.address = NULL;
4000           shost.port = port;
4001           shost.mx = -1;
4002
4003           namelen = Ustrlen(server_name);
4004
4005           /* Anything enclosed in [] must be an IP address. */
4006
4007           if (server_name[0] == '[' &&
4008               server_name[namelen - 1] == ']')
4009             {
4010             server_name[namelen - 1] = 0;
4011             server_name++;
4012             if (string_is_ip_address(server_name, NULL) == 0)
4013               {
4014               expand_string_message =
4015                 string_sprintf("malformed IP address \"%s\"", server_name);
4016               goto EXPAND_FAILED;
4017               }
4018             shost.name = shost.address = server_name;
4019             }
4020
4021           /* Otherwise check for an unadorned IP address */
4022
4023           else if (string_is_ip_address(server_name, NULL) != 0)
4024             shost.name = shost.address = server_name;
4025
4026           /* Otherwise lookup IP address(es) from the name */
4027
4028           else
4029             {
4030             shost.name = server_name;
4031             if (host_find_byname(&shost, NULL, HOST_FIND_QUALIFY_SINGLE, NULL,
4032                 FALSE) != HOST_FOUND)
4033               {
4034               expand_string_message =
4035                 string_sprintf("no IP address found for host %s", shost.name);
4036               goto EXPAND_FAILED;
4037               }
4038             }
4039
4040           /* Try to connect to the server - test each IP till one works */
4041
4042           for (h = &shost; h != NULL; h = h->next)
4043             {
4044             int af = (Ustrchr(h->address, ':') != 0)? AF_INET6 : AF_INET;
4045             if ((fd = ip_socket(SOCK_STREAM, af)) == -1)
4046               {
4047               expand_string_message = string_sprintf("failed to create socket: "
4048                 "%s", strerror(errno));
4049               goto SOCK_FAIL;
4050               }
4051
4052             if (ip_connect(fd, af, h->address, port, timeout) == 0)
4053               {
4054               connected = TRUE;
4055               break;
4056               }
4057             }
4058
4059           if (!connected)
4060             {
4061             expand_string_message = string_sprintf("failed to connect to "
4062               "socket %s: couldn't connect to any host", sub_arg[0],
4063               strerror(errno));
4064             goto SOCK_FAIL;
4065             }
4066           }
4067
4068         /* Handle a Unix domain socket */
4069
4070         else
4071           {
4072           int rc;
4073           if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
4074             {
4075             expand_string_message = string_sprintf("failed to create socket: %s",
4076               strerror(errno));
4077             goto SOCK_FAIL;
4078             }
4079
4080           sockun.sun_family = AF_UNIX;
4081           sprintf(sockun.sun_path, "%.*s", (int)(sizeof(sockun.sun_path)-1),
4082             sub_arg[0]);
4083
4084           sigalrm_seen = FALSE;
4085           alarm(timeout);
4086           rc = connect(fd, (struct sockaddr *)(&sockun), sizeof(sockun));
4087           alarm(0);
4088           if (sigalrm_seen)
4089             {
4090             expand_string_message = US "socket connect timed out";
4091             goto SOCK_FAIL;
4092             }
4093           if (rc < 0)
4094             {
4095             expand_string_message = string_sprintf("failed to connect to socket "
4096               "%s: %s", sub_arg[0], strerror(errno));
4097             goto SOCK_FAIL;
4098             }
4099           }
4100
4101         DEBUG(D_expand) debug_printf("connected to socket %s\n", sub_arg[0]);
4102
4103         /* Write the request string, if not empty */
4104
4105         if (sub_arg[1][0] != 0)
4106           {
4107           int len = Ustrlen(sub_arg[1]);
4108           DEBUG(D_expand) debug_printf("writing \"%s\" to socket\n",
4109             sub_arg[1]);
4110           if (write(fd, sub_arg[1], len) != len)
4111             {
4112             expand_string_message = string_sprintf("request write to socket "
4113               "failed: %s", strerror(errno));
4114             goto SOCK_FAIL;
4115             }
4116           }
4117
4118         /* Shut down the sending side of the socket. This helps some servers to
4119         recognise that it is their turn to do some work. Just in case some
4120         system doesn't have this function, make it conditional. */
4121
4122         #ifdef SHUT_WR
4123         shutdown(fd, SHUT_WR);
4124         #endif
4125
4126         /* Now we need to read from the socket, under a timeout. The function
4127         that reads a file can be used. */
4128
4129         f = fdopen(fd, "rb");
4130         sigalrm_seen = FALSE;
4131         alarm(timeout);
4132         yield = cat_file(f, yield, &size, &ptr, sub_arg[3]);
4133         alarm(0);
4134         (void)fclose(f);
4135
4136         /* After a timeout, we restore the pointer in the result, that is,
4137         make sure we add nothing from the socket. */
4138
4139         if (sigalrm_seen)
4140           {
4141           ptr = save_ptr;
4142           expand_string_message = US "socket read timed out";
4143           goto SOCK_FAIL;
4144           }
4145         }
4146
4147       /* The whole thing has worked (or we were skipping). If there is a
4148       failure string following, we need to skip it. */
4149
4150       if (*s == '{')
4151         {
4152         if (expand_string_internal(s+1, TRUE, &s, TRUE) == NULL)
4153           goto EXPAND_FAILED;
4154         if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4155         while (isspace(*s)) s++;
4156         }
4157       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4158       continue;
4159
4160       /* Come here on failure to create socket, connect socket, write to the
4161       socket, or timeout on reading. If another substring follows, expand and
4162       use it. Otherwise, those conditions give expand errors. */
4163
4164       SOCK_FAIL:
4165       if (*s != '{') goto EXPAND_FAILED;
4166       DEBUG(D_any) debug_printf("%s\n", expand_string_message);
4167       arg = expand_string_internal(s+1, TRUE, &s, FALSE);
4168       if (arg == NULL) goto EXPAND_FAILED;
4169       yield = string_cat(yield, &size, &ptr, arg, Ustrlen(arg));
4170       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4171       while (isspace(*s)) s++;
4172       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4173       continue;
4174       }
4175
4176     /* Handle "run" to execute a program. */
4177
4178     case EITEM_RUN:
4179       {
4180       FILE *f;
4181       uschar *arg;
4182       uschar **argv;
4183       pid_t pid;
4184       int fd_in, fd_out;
4185       int lsize = 0;
4186       int lptr = 0;
4187
4188       if ((expand_forbid & RDO_RUN) != 0)
4189         {
4190         expand_string_message = US"running a command is not permitted";
4191         goto EXPAND_FAILED;
4192         }
4193
4194       while (isspace(*s)) s++;
4195       if (*s != '{') goto EXPAND_FAILED_CURLY;
4196       arg = expand_string_internal(s+1, TRUE, &s, skipping);
4197       if (arg == NULL) goto EXPAND_FAILED;
4198       while (isspace(*s)) s++;
4199       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4200
4201       if (skipping)   /* Just pretend it worked when we're skipping */
4202         {
4203         runrc = 0;
4204         }
4205       else
4206         {
4207         if (!transport_set_up_command(&argv,    /* anchor for arg list */
4208             arg,                                /* raw command */
4209             FALSE,                              /* don't expand the arguments */
4210             0,                                  /* not relevant when... */
4211             NULL,                               /* no transporting address */
4212             US"${run} expansion",               /* for error messages */
4213             &expand_string_message))            /* where to put error message */
4214           {
4215           goto EXPAND_FAILED;
4216           }
4217
4218         /* Create the child process, making it a group leader. */
4219
4220         pid = child_open(argv, NULL, 0077, &fd_in, &fd_out, TRUE);
4221
4222         if (pid < 0)
4223           {
4224           expand_string_message =
4225             string_sprintf("couldn't create child process: %s", strerror(errno));
4226           goto EXPAND_FAILED;
4227           }
4228
4229         /* Nothing is written to the standard input. */
4230
4231         (void)close(fd_in);
4232
4233         /* Wait for the process to finish, applying the timeout, and inspect its
4234         return code for serious disasters. Simple non-zero returns are passed on.
4235         */
4236
4237         if ((runrc = child_close(pid, 60)) < 0)
4238           {
4239           if (runrc == -256)
4240             {
4241             expand_string_message = string_sprintf("command timed out");
4242             killpg(pid, SIGKILL);       /* Kill the whole process group */
4243             }
4244
4245           else if (runrc == -257)
4246             expand_string_message = string_sprintf("wait() failed: %s",
4247               strerror(errno));
4248
4249           else
4250             expand_string_message = string_sprintf("command killed by signal %d",
4251               -runrc);
4252
4253           goto EXPAND_FAILED;
4254           }
4255
4256         /* Read the pipe to get the command's output into $value (which is kept
4257         in lookup_value). */
4258
4259         f = fdopen(fd_out, "rb");
4260         lookup_value = NULL;
4261         lookup_value = cat_file(f, lookup_value, &lsize, &lptr, NULL);
4262         (void)fclose(f);
4263         }
4264
4265       /* Process the yes/no strings; $value may be useful in both cases */
4266
4267       switch(process_yesno(
4268                skipping,                     /* were previously skipping */
4269                runrc == 0,                   /* success/failure indicator */
4270                lookup_value,                 /* value to reset for string2 */
4271                &s,                           /* input pointer */
4272                &yield,                       /* output pointer */
4273                &size,                        /* output size */
4274                &ptr,                         /* output current point */
4275                US"run"))                     /* condition type */
4276         {
4277         case 1: goto EXPAND_FAILED;          /* when all is well, the */
4278         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
4279         }
4280
4281       continue;
4282       }
4283
4284     /* Handle character translation for "tr" */
4285
4286     case EITEM_TR:
4287       {
4288       int oldptr = ptr;
4289       int o2m;
4290       uschar *sub[3];
4291
4292       switch(read_subs(sub, 3, 3, &s, skipping, TRUE, US"tr"))
4293         {
4294         case 1: goto EXPAND_FAILED_CURLY;
4295         case 2:
4296         case 3: goto EXPAND_FAILED;
4297         }
4298
4299       yield = string_cat(yield, &size, &ptr, sub[0], Ustrlen(sub[0]));
4300       o2m = Ustrlen(sub[2]) - 1;
4301
4302       if (o2m >= 0) for (; oldptr < ptr; oldptr++)
4303         {
4304         uschar *m = Ustrrchr(sub[1], yield[oldptr]);
4305         if (m != NULL)
4306           {
4307           int o = m - sub[1];
4308           yield[oldptr] = sub[2][(o < o2m)? o : o2m];
4309           }
4310         }
4311
4312       continue;
4313       }
4314
4315     /* Handle "hash", "length", "nhash", and "substr" when they are given with
4316     expanded arguments. */
4317
4318     case EITEM_HASH:
4319     case EITEM_LENGTH:
4320     case EITEM_NHASH:
4321     case EITEM_SUBSTR:
4322       {
4323       int i;
4324       int len;
4325       uschar *ret;
4326       int val[2] = { 0, -1 };
4327       uschar *sub[3];
4328
4329       /* "length" takes only 2 arguments whereas the others take 2 or 3.
4330       Ensure that sub[2] is set in the ${length case. */
4331
4332       sub[2] = NULL;
4333       switch(read_subs(sub, (item_type == EITEM_LENGTH)? 2:3, 2, &s, skipping,
4334              TRUE, name))
4335         {
4336         case 1: goto EXPAND_FAILED_CURLY;
4337         case 2:
4338         case 3: goto EXPAND_FAILED;
4339         }
4340
4341       /* Juggle the arguments if there are only two of them: always move the
4342       string to the last position and make ${length{n}{str}} equivalent to
4343       ${substr{0}{n}{str}}. See the defaults for val[] above. */
4344
4345       if (sub[2] == NULL)
4346         {
4347         sub[2] = sub[1];
4348         sub[1] = NULL;
4349         if (item_type == EITEM_LENGTH)
4350           {
4351           sub[1] = sub[0];
4352           sub[0] = NULL;
4353           }
4354         }
4355
4356       for (i = 0; i < 2; i++)
4357         {
4358         if (sub[i] == NULL) continue;
4359         val[i] = (int)Ustrtol(sub[i], &ret, 10);
4360         if (*ret != 0 || (i != 0 && val[i] < 0))
4361           {
4362           expand_string_message = string_sprintf("\"%s\" is not a%s number "
4363             "(in \"%s\" expansion)", sub[i], (i != 0)? " positive" : "", name);
4364           goto EXPAND_FAILED;
4365           }
4366         }
4367
4368       ret =
4369         (item_type == EITEM_HASH)?
4370           compute_hash(sub[2], val[0], val[1], &len) :
4371         (item_type == EITEM_NHASH)?
4372           compute_nhash(sub[2], val[0], val[1], &len) :
4373           extract_substr(sub[2], val[0], val[1], &len);
4374
4375       if (ret == NULL) goto EXPAND_FAILED;
4376       yield = string_cat(yield, &size, &ptr, ret, len);
4377       continue;
4378       }
4379
4380     /* Handle HMAC computation: ${hmac{<algorithm>}{<secret>}{<text>}}
4381     This code originally contributed by Steve Haslam. It currently supports
4382     the use of MD5 and SHA-1 hashes.
4383
4384     We need some workspace that is large enough to handle all the supported
4385     hash types. Use macros to set the sizes rather than be too elaborate. */
4386
4387     #define MAX_HASHLEN      20
4388     #define MAX_HASHBLOCKLEN 64
4389
4390     case EITEM_HMAC:
4391       {
4392       uschar *sub[3];
4393       md5 md5_base;
4394       sha1 sha1_base;
4395       void *use_base;
4396       int type, i;
4397       int hashlen;      /* Number of octets for the hash algorithm's output */
4398       int hashblocklen; /* Number of octets the hash algorithm processes */
4399       uschar *keyptr, *p;
4400       unsigned int keylen;
4401
4402       uschar keyhash[MAX_HASHLEN];
4403       uschar innerhash[MAX_HASHLEN];
4404       uschar finalhash[MAX_HASHLEN];
4405       uschar finalhash_hex[2*MAX_HASHLEN];
4406       uschar innerkey[MAX_HASHBLOCKLEN];
4407       uschar outerkey[MAX_HASHBLOCKLEN];
4408
4409       switch (read_subs(sub, 3, 3, &s, skipping, TRUE, name))
4410         {
4411         case 1: goto EXPAND_FAILED_CURLY;
4412         case 2:
4413         case 3: goto EXPAND_FAILED;
4414         }
4415
4416       if (Ustrcmp(sub[0], "md5") == 0)
4417         {
4418         type = HMAC_MD5;
4419         use_base = &md5_base;
4420         hashlen = 16;
4421         hashblocklen = 64;
4422         }
4423       else if (Ustrcmp(sub[0], "sha1") == 0)
4424         {
4425         type = HMAC_SHA1;
4426         use_base = &sha1_base;
4427         hashlen = 20;
4428         hashblocklen = 64;
4429         }
4430       else
4431         {
4432         expand_string_message =
4433           string_sprintf("hmac algorithm \"%s\" is not recognised", sub[0]);
4434         goto EXPAND_FAILED;
4435         }
4436
4437       keyptr = sub[1];
4438       keylen = Ustrlen(keyptr);
4439
4440       /* If the key is longer than the hash block length, then hash the key
4441       first */
4442
4443       if (keylen > hashblocklen)
4444         {
4445         chash_start(type, use_base);
4446         chash_end(type, use_base, keyptr, keylen, keyhash);
4447         keyptr = keyhash;
4448         keylen = hashlen;
4449         }
4450
4451       /* Now make the inner and outer key values */
4452
4453       memset(innerkey, 0x36, hashblocklen);
4454       memset(outerkey, 0x5c, hashblocklen);
4455
4456       for (i = 0; i < keylen; i++)
4457         {
4458         innerkey[i] ^= keyptr[i];
4459         outerkey[i] ^= keyptr[i];
4460         }
4461
4462       /* Now do the hashes */
4463
4464       chash_start(type, use_base);
4465       chash_mid(type, use_base, innerkey);
4466       chash_end(type, use_base, sub[2], Ustrlen(sub[2]), innerhash);
4467
4468       chash_start(type, use_base);
4469       chash_mid(type, use_base, outerkey);
4470       chash_end(type, use_base, innerhash, hashlen, finalhash);
4471
4472       /* Encode the final hash as a hex string */
4473
4474       p = finalhash_hex;
4475       for (i = 0; i < hashlen; i++)
4476         {
4477         *p++ = hex_digits[(finalhash[i] & 0xf0) >> 4];
4478         *p++ = hex_digits[finalhash[i] & 0x0f];
4479         }
4480
4481       DEBUG(D_any) debug_printf("HMAC[%s](%.*s,%.*s)=%.*s\n", sub[0],
4482         (int)keylen, keyptr, Ustrlen(sub[2]), sub[2], hashlen*2, finalhash_hex);
4483
4484       yield = string_cat(yield, &size, &ptr, finalhash_hex, hashlen*2);
4485       }
4486
4487     continue;
4488
4489     /* Handle global substitution for "sg" - like Perl's s/xxx/yyy/g operator.
4490     We have to save the numerical variables and restore them afterwards. */
4491
4492     case EITEM_SG:
4493       {
4494       const pcre *re;
4495       int moffset, moffsetextra, slen;
4496       int roffset;
4497       int emptyopt;
4498       const uschar *rerror;
4499       uschar *subject;
4500       uschar *sub[3];
4501       int save_expand_nmax =
4502         save_expand_strings(save_expand_nstring, save_expand_nlength);
4503
4504       switch(read_subs(sub, 3, 3, &s, skipping, TRUE, US"sg"))
4505         {
4506         case 1: goto EXPAND_FAILED_CURLY;
4507         case 2:
4508         case 3: goto EXPAND_FAILED;
4509         }
4510
4511       /* Compile the regular expression */
4512
4513       re = pcre_compile(CS sub[1], PCRE_COPT, (const char **)&rerror, &roffset,
4514         NULL);
4515
4516       if (re == NULL)
4517         {
4518         expand_string_message = string_sprintf("regular expression error in "
4519           "\"%s\": %s at offset %d", sub[1], rerror, roffset);
4520         goto EXPAND_FAILED;
4521         }
4522
4523       /* Now run a loop to do the substitutions as often as necessary. It ends
4524       when there are no more matches. Take care over matches of the null string;
4525       do the same thing as Perl does. */
4526
4527       subject = sub[0];
4528       slen = Ustrlen(sub[0]);
4529       moffset = moffsetextra = 0;
4530       emptyopt = 0;
4531
4532       for (;;)
4533         {
4534         int ovector[3*(EXPAND_MAXN+1)];
4535         int n = pcre_exec(re, NULL, CS subject, slen, moffset + moffsetextra,
4536           PCRE_EOPT | emptyopt, ovector, sizeof(ovector)/sizeof(int));
4537         int nn;
4538         uschar *insert;
4539
4540         /* No match - if we previously set PCRE_NOTEMPTY after a null match, this
4541         is not necessarily the end. We want to repeat the match from one
4542         character further along, but leaving the basic offset the same (for
4543         copying below). We can't be at the end of the string - that was checked
4544         before setting PCRE_NOTEMPTY. If PCRE_NOTEMPTY is not set, we are
4545         finished; copy the remaining string and end the loop. */
4546
4547         if (n < 0)
4548           {
4549           if (emptyopt != 0)
4550             {
4551             moffsetextra = 1;
4552             emptyopt = 0;
4553             continue;
4554             }
4555           yield = string_cat(yield, &size, &ptr, subject+moffset, slen-moffset);
4556           break;
4557           }
4558
4559         /* Match - set up for expanding the replacement. */
4560
4561         if (n == 0) n = EXPAND_MAXN + 1;
4562         expand_nmax = 0;
4563         for (nn = 0; nn < n*2; nn += 2)
4564           {
4565           expand_nstring[expand_nmax] = subject + ovector[nn];
4566           expand_nlength[expand_nmax++] = ovector[nn+1] - ovector[nn];
4567           }
4568         expand_nmax--;
4569
4570         /* Copy the characters before the match, plus the expanded insertion. */
4571
4572         yield = string_cat(yield, &size, &ptr, subject + moffset,
4573           ovector[0] - moffset);
4574         insert = expand_string(sub[2]);
4575         if (insert == NULL) goto EXPAND_FAILED;
4576         yield = string_cat(yield, &size, &ptr, insert, Ustrlen(insert));
4577
4578         moffset = ovector[1];
4579         moffsetextra = 0;
4580         emptyopt = 0;
4581
4582         /* If we have matched an empty string, first check to see if we are at
4583         the end of the subject. If so, the loop is over. Otherwise, mimic
4584         what Perl's /g options does. This turns out to be rather cunning. First
4585         we set PCRE_NOTEMPTY and PCRE_ANCHORED and try the match a non-empty
4586         string at the same point. If this fails (picked up above) we advance to
4587         the next character. */
4588
4589         if (ovector[0] == ovector[1])
4590           {
4591           if (ovector[0] == slen) break;
4592           emptyopt = PCRE_NOTEMPTY | PCRE_ANCHORED;
4593           }
4594         }
4595
4596       /* All done - restore numerical variables. */
4597
4598       restore_expand_strings(save_expand_nmax, save_expand_nstring,
4599         save_expand_nlength);
4600       continue;
4601       }
4602
4603     /* Handle keyed and numbered substring extraction. If the first argument
4604     consists entirely of digits, then a numerical extraction is assumed. */
4605
4606     case EITEM_EXTRACT:
4607       {
4608       int i;
4609       int j = 2;
4610       int field_number = 1;
4611       BOOL field_number_set = FALSE;
4612       uschar *save_lookup_value = lookup_value;
4613       uschar *sub[3];
4614       int save_expand_nmax =
4615         save_expand_strings(save_expand_nstring, save_expand_nlength);
4616
4617       /* Read the arguments */
4618
4619       for (i = 0; i < j; i++)
4620         {
4621         while (isspace(*s)) s++;
4622         if (*s == '{')
4623           {
4624           sub[i] = expand_string_internal(s+1, TRUE, &s, skipping);
4625           if (sub[i] == NULL) goto EXPAND_FAILED;
4626           if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4627
4628           /* After removal of leading and trailing white space, the first
4629           argument must not be empty; if it consists entirely of digits
4630           (optionally preceded by a minus sign), this is a numerical
4631           extraction, and we expect 3 arguments. */
4632
4633           if (i == 0)
4634             {
4635             int len;
4636             int x = 0;
4637             uschar *p = sub[0];
4638
4639             while (isspace(*p)) p++;
4640             sub[0] = p;
4641
4642             len = Ustrlen(p);
4643             while (len > 0 && isspace(p[len-1])) len--;
4644             p[len] = 0;
4645
4646             if (*p == 0)
4647               {
4648               expand_string_message = US"first argument of \"extract\" must "
4649                 "not be empty";
4650               goto EXPAND_FAILED;
4651               }
4652
4653             if (*p == '-')
4654               {
4655               field_number = -1;
4656               p++;
4657               }
4658             while (*p != 0 && isdigit(*p)) x = x * 10 + *p++ - '0';
4659             if (*p == 0)
4660               {
4661               field_number *= x;
4662               j = 3;               /* Need 3 args */
4663               field_number_set = TRUE;
4664               }
4665             }
4666           }
4667         else goto EXPAND_FAILED_CURLY;
4668         }
4669
4670       /* Extract either the numbered or the keyed substring into $value. If
4671       skipping, just pretend the extraction failed. */
4672
4673       lookup_value = skipping? NULL : field_number_set?
4674         expand_gettokened(field_number, sub[1], sub[2]) :
4675         expand_getkeyed(sub[0], sub[1]);
4676
4677       /* If no string follows, $value gets substituted; otherwise there can
4678       be yes/no strings, as for lookup or if. */
4679
4680       switch(process_yesno(
4681                skipping,                     /* were previously skipping */
4682                lookup_value != NULL,         /* success/failure indicator */
4683                save_lookup_value,            /* value to reset for string2 */
4684                &s,                           /* input pointer */
4685                &yield,                       /* output pointer */
4686                &size,                        /* output size */
4687                &ptr,                         /* output current point */
4688                US"extract"))                 /* condition type */
4689         {
4690         case 1: goto EXPAND_FAILED;          /* when all is well, the */
4691         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
4692         }
4693
4694       /* All done - restore numerical variables. */
4695
4696       restore_expand_strings(save_expand_nmax, save_expand_nstring,
4697         save_expand_nlength);
4698
4699       continue;
4700       }
4701
4702
4703     /* Handle list operations */
4704
4705     case EITEM_FILTER:
4706     case EITEM_MAP:
4707     case EITEM_REDUCE:
4708       {
4709       int sep = 0;
4710       int save_ptr = ptr;
4711       uschar outsep[2] = { '\0', '\0' };
4712       uschar *list, *expr, *temp;
4713       uschar *save_iterate_item = iterate_item;
4714       uschar *save_lookup_value = lookup_value;
4715
4716       while (isspace(*s)) s++;
4717       if (*s++ != '{') goto EXPAND_FAILED_CURLY;
4718
4719       list = expand_string_internal(s, TRUE, &s, skipping);
4720       if (list == NULL) goto EXPAND_FAILED;
4721       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4722
4723       if (item_type == EITEM_REDUCE)
4724         {
4725         while (isspace(*s)) s++;
4726         if (*s++ != '{') goto EXPAND_FAILED_CURLY;
4727         temp = expand_string_internal(s, TRUE, &s, skipping);
4728         if (temp == NULL) goto EXPAND_FAILED;
4729         lookup_value = temp;
4730         if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4731         }
4732
4733       while (isspace(*s)) s++;
4734       if (*s++ != '{') goto EXPAND_FAILED_CURLY;
4735
4736       expr = s;
4737
4738       /* For EITEM_FILTER, call eval_condition once, with result discarded (as
4739       if scanning a "false" part). This allows us to find the end of the
4740       condition, because if the list is empty, we won't actually evaluate the
4741       condition for real. For EITEM_MAP and EITEM_REDUCE, do the same, using
4742       the normal internal expansion function. */
4743
4744       if (item_type == EITEM_FILTER)
4745         {
4746         temp = eval_condition(expr, NULL);
4747         if (temp != NULL) s = temp;
4748         }
4749       else
4750         {
4751         temp = expand_string_internal(s, TRUE, &s, TRUE);
4752         }
4753
4754       if (temp == NULL)
4755         {
4756         expand_string_message = string_sprintf("%s inside \"%s\" item",
4757           expand_string_message, name);
4758         goto EXPAND_FAILED;
4759         }
4760
4761       while (isspace(*s)) s++;
4762       if (*s++ != '}')
4763         {
4764         expand_string_message = string_sprintf("missing } at end of condition "
4765           "or expression inside \"%s\"", name);
4766         goto EXPAND_FAILED;
4767         }
4768
4769       while (isspace(*s)) s++;
4770       if (*s++ != '}')
4771         {
4772         expand_string_message = string_sprintf("missing } at end of \"%s\"",
4773           name);
4774         goto EXPAND_FAILED;
4775         }
4776
4777       /* If we are skipping, we can now just move on to the next item. When
4778       processing for real, we perform the iteration. */
4779
4780       if (skipping) continue;
4781       while ((iterate_item = string_nextinlist(&list, &sep, NULL, 0)) != NULL)
4782         {
4783         *outsep = (uschar)sep;      /* Separator as a string */
4784
4785         DEBUG(D_expand) debug_printf("%s: $item = \"%s\"\n", name, iterate_item);
4786
4787         if (item_type == EITEM_FILTER)
4788           {
4789           BOOL condresult;
4790           if (eval_condition(expr, &condresult) == NULL)
4791             {
4792             iterate_item = save_iterate_item;
4793             lookup_value = save_lookup_value;
4794             expand_string_message = string_sprintf("%s inside \"%s\" condition",
4795               expand_string_message, name);
4796             goto EXPAND_FAILED;
4797             }
4798           DEBUG(D_expand) debug_printf("%s: condition is %s\n", name,
4799             condresult? "true":"false");
4800           if (condresult)
4801             temp = iterate_item;    /* TRUE => include this item */
4802           else
4803             continue;               /* FALSE => skip this item */
4804           }
4805
4806         /* EITEM_MAP and EITEM_REDUCE */
4807
4808         else
4809           {
4810           temp = expand_string_internal(expr, TRUE, NULL, skipping);
4811           if (temp == NULL)
4812             {
4813             iterate_item = save_iterate_item;
4814             expand_string_message = string_sprintf("%s inside \"%s\" item",
4815               expand_string_message, name);
4816             goto EXPAND_FAILED;
4817             }
4818           if (item_type == EITEM_REDUCE)
4819             {
4820             lookup_value = temp;      /* Update the value of $value */
4821             continue;                 /* and continue the iteration */
4822             }
4823           }
4824
4825         /* We reach here for FILTER if the condition is true, always for MAP,
4826         and never for REDUCE. The value in "temp" is to be added to the output
4827         list that is being created, ensuring that any occurrences of the
4828         separator character are doubled. Unless we are dealing with the first
4829         item of the output list, add in a space if the new item begins with the
4830         separator character, or is an empty string. */
4831
4832         if (ptr != save_ptr && (temp[0] == *outsep || temp[0] == 0))
4833           yield = string_cat(yield, &size, &ptr, US" ", 1);
4834
4835         /* Add the string in "temp" to the output list that we are building,
4836         This is done in chunks by searching for the separator character. */
4837
4838         for (;;)
4839           {
4840           size_t seglen = Ustrcspn(temp, outsep);
4841             yield = string_cat(yield, &size, &ptr, temp, seglen + 1);
4842
4843           /* If we got to the end of the string we output one character
4844           too many; backup and end the loop. Otherwise arrange to double the
4845           separator. */
4846
4847           if (temp[seglen] == '\0') { ptr--; break; }
4848           yield = string_cat(yield, &size, &ptr, outsep, 1);
4849           temp += seglen + 1;
4850           }
4851
4852         /* Output a separator after the string: we will remove the redundant
4853         final one at the end. */
4854
4855         yield = string_cat(yield, &size, &ptr, outsep, 1);
4856         }   /* End of iteration over the list loop */
4857
4858       /* REDUCE has generated no output above: output the final value of
4859       $value. */
4860
4861       if (item_type == EITEM_REDUCE)
4862         {
4863         yield = string_cat(yield, &size, &ptr, lookup_value,
4864           Ustrlen(lookup_value));
4865         lookup_value = save_lookup_value;  /* Restore $value */
4866         }
4867
4868       /* FILTER and MAP generate lists: if they have generated anything, remove
4869       the redundant final separator. Even though an empty item at the end of a
4870       list does not count, this is tidier. */
4871
4872       else if (ptr != save_ptr) ptr--;
4873
4874       /* Restore preserved $item */
4875
4876       iterate_item = save_iterate_item;
4877       continue;
4878       }
4879
4880
4881     /* If ${dlfunc support is configured, handle calling dynamically-loaded
4882     functions, unless locked out at this time. Syntax is ${dlfunc{file}{func}}
4883     or ${dlfunc{file}{func}{arg}} or ${dlfunc{file}{func}{arg1}{arg2}} or up to
4884     a maximum of EXPAND_DLFUNC_MAX_ARGS arguments (defined below). */
4885
4886     #define EXPAND_DLFUNC_MAX_ARGS 8
4887
4888     case EITEM_DLFUNC:
4889     #ifndef EXPAND_DLFUNC
4890     expand_string_message = US"\"${dlfunc\" encountered, but this facility "
4891       "is not included in this binary";
4892     goto EXPAND_FAILED;
4893
4894     #else   /* EXPAND_DLFUNC */
4895       {
4896       tree_node *t;
4897       exim_dlfunc_t *func;
4898       uschar *result;
4899       int status, argc;
4900       uschar *argv[EXPAND_DLFUNC_MAX_ARGS + 3];
4901
4902       if ((expand_forbid & RDO_DLFUNC) != 0)
4903         {
4904         expand_string_message =
4905           US"dynamically-loaded functions are not permitted";
4906         goto EXPAND_FAILED;
4907         }
4908
4909       switch(read_subs(argv, EXPAND_DLFUNC_MAX_ARGS + 2, 2, &s, skipping,
4910            TRUE, US"dlfunc"))
4911         {
4912         case 1: goto EXPAND_FAILED_CURLY;
4913         case 2:
4914         case 3: goto EXPAND_FAILED;
4915         }
4916
4917       /* If skipping, we don't actually do anything */
4918
4919       if (skipping) continue;
4920
4921       /* Look up the dynamically loaded object handle in the tree. If it isn't
4922       found, dlopen() the file and put the handle in the tree for next time. */
4923
4924       t = tree_search(dlobj_anchor, argv[0]);
4925       if (t == NULL)
4926         {
4927         void *handle = dlopen(CS argv[0], RTLD_LAZY);
4928         if (handle == NULL)
4929           {
4930           expand_string_message = string_sprintf("dlopen \"%s\" failed: %s",
4931             argv[0], dlerror());
4932           log_write(0, LOG_MAIN|LOG_PANIC, "%s", expand_string_message);
4933           goto EXPAND_FAILED;
4934           }
4935         t = store_get_perm(sizeof(tree_node) + Ustrlen(argv[0]));
4936         Ustrcpy(t->name, argv[0]);
4937         t->data.ptr = handle;
4938         (void)tree_insertnode(&dlobj_anchor, t);
4939         }
4940
4941       /* Having obtained the dynamically loaded object handle, look up the
4942       function pointer. */
4943
4944       func = (exim_dlfunc_t *)dlsym(t->data.ptr, CS argv[1]);
4945       if (func == NULL)
4946         {
4947         expand_string_message = string_sprintf("dlsym \"%s\" in \"%s\" failed: "
4948           "%s", argv[1], argv[0], dlerror());
4949         log_write(0, LOG_MAIN|LOG_PANIC, "%s", expand_string_message);
4950         goto EXPAND_FAILED;
4951         }
4952
4953       /* Call the function and work out what to do with the result. If it
4954       returns OK, we have a replacement string; if it returns DEFER then
4955       expansion has failed in a non-forced manner; if it returns FAIL then
4956       failure was forced; if it returns ERROR or any other value there's a
4957       problem, so panic slightly. */
4958
4959       result = NULL;
4960       for (argc = 0; argv[argc] != NULL; argc++);
4961       status = func(&result, argc - 2, &argv[2]);
4962       if(status == OK)
4963         {
4964         if (result == NULL) result = US"";
4965         yield = string_cat(yield, &size, &ptr, result, Ustrlen(result));
4966         continue;
4967         }
4968       else
4969         {
4970         expand_string_message = result == NULL ? US"(no message)" : result;
4971         if(status == FAIL_FORCED) expand_string_forcedfail = TRUE;
4972           else if(status != FAIL)
4973             log_write(0, LOG_MAIN|LOG_PANIC, "dlfunc{%s}{%s} failed (%d): %s",
4974               argv[0], argv[1], status, expand_string_message);
4975         goto EXPAND_FAILED;
4976         }
4977       }
4978     #endif /* EXPAND_DLFUNC */
4979     }
4980
4981   /* Control reaches here if the name is not recognized as one of the more
4982   complicated expansion items. Check for the "operator" syntax (name terminated
4983   by a colon). Some of the operators have arguments, separated by _ from the
4984   name. */
4985
4986   if (*s == ':')
4987     {
4988     int c;
4989     uschar *arg = NULL;
4990     uschar *sub = expand_string_internal(s+1, TRUE, &s, skipping);
4991     if (sub == NULL) goto EXPAND_FAILED;
4992     s++;
4993
4994     /* Owing to an historical mis-design, an underscore may be part of the
4995     operator name, or it may introduce arguments.  We therefore first scan the
4996     table of names that contain underscores. If there is no match, we cut off
4997     the arguments and then scan the main table. */
4998
4999     c = chop_match(name, op_table_underscore,
5000       sizeof(op_table_underscore)/sizeof(uschar *));
5001
5002     if (c < 0)
5003       {
5004       arg = Ustrchr(name, '_');
5005       if (arg != NULL) *arg = 0;
5006       c = chop_match(name, op_table_main,
5007         sizeof(op_table_main)/sizeof(uschar *));
5008       if (c >= 0) c += sizeof(op_table_underscore)/sizeof(uschar *);
5009       if (arg != NULL) *arg++ = '_';   /* Put back for error messages */
5010       }
5011
5012     /* If we are skipping, we don't need to perform the operation at all.
5013     This matters for operations like "mask", because the data may not be
5014     in the correct format when skipping. For example, the expression may test
5015     for the existence of $sender_host_address before trying to mask it. For
5016     other operations, doing them may not fail, but it is a waste of time. */
5017
5018     if (skipping && c >= 0) continue;
5019
5020     /* Otherwise, switch on the operator type */
5021
5022     switch(c)
5023       {
5024       case EOP_BASE62:
5025         {
5026         uschar *t;
5027         unsigned long int n = Ustrtoul(sub, &t, 10);
5028         if (*t != 0)
5029           {
5030           expand_string_message = string_sprintf("argument for base62 "
5031             "operator is \"%s\", which is not a decimal number", sub);
5032           goto EXPAND_FAILED;
5033           }
5034         t = string_base62(n);
5035         yield = string_cat(yield, &size, &ptr, t, Ustrlen(t));
5036         continue;
5037         }
5038
5039       /* Note that for Darwin and Cygwin, BASE_62 actually has the value 36 */
5040
5041       case EOP_BASE62D:
5042         {
5043         uschar buf[16];
5044         uschar *tt = sub;
5045         unsigned long int n = 0;
5046         while (*tt != 0)
5047           {
5048           uschar *t = Ustrchr(base62_chars, *tt++);
5049           if (t == NULL)
5050             {
5051             expand_string_message = string_sprintf("argument for base62d "
5052               "operator is \"%s\", which is not a base %d number", sub,
5053               BASE_62);
5054             goto EXPAND_FAILED;
5055             }
5056           n = n * BASE_62 + (t - base62_chars);
5057           }
5058         (void)sprintf(CS buf, "%ld", n);
5059         yield = string_cat(yield, &size, &ptr, buf, Ustrlen(buf));
5060         continue;
5061         }
5062
5063       case EOP_EXPAND:
5064         {
5065         uschar *expanded = expand_string_internal(sub, FALSE, NULL, skipping);
5066         if (expanded == NULL)
5067           {
5068           expand_string_message =
5069             string_sprintf("internal expansion of \"%s\" failed: %s", sub,
5070               expand_string_message);
5071           goto EXPAND_FAILED;
5072           }
5073         yield = string_cat(yield, &size, &ptr, expanded, Ustrlen(expanded));
5074         continue;
5075         }
5076
5077       case EOP_LC:
5078         {
5079         int count = 0;
5080         uschar *t = sub - 1;
5081         while (*(++t) != 0) { *t = tolower(*t); count++; }
5082         yield = string_cat(yield, &size, &ptr, sub, count);
5083         continue;
5084         }
5085
5086       case EOP_UC:
5087         {
5088         int count = 0;
5089         uschar *t = sub - 1;
5090         while (*(++t) != 0) { *t = toupper(*t); count++; }
5091         yield = string_cat(yield, &size, &ptr, sub, count);
5092         continue;
5093         }
5094
5095       case EOP_MD5:
5096         {
5097         md5 base;
5098         uschar digest[16];
5099         int j;
5100         char st[33];
5101         md5_start(&base);
5102         md5_end(&base, sub, Ustrlen(sub), digest);
5103         for(j = 0; j < 16; j++) sprintf(st+2*j, "%02x", digest[j]);
5104         yield = string_cat(yield, &size, &ptr, US st, (int)strlen(st));
5105         continue;
5106         }
5107
5108       case EOP_SHA1:
5109         {
5110         sha1 base;
5111         uschar digest[20];
5112         int j;
5113         char st[41];
5114         sha1_start(&base);
5115         sha1_end(&base, sub, Ustrlen(sub), digest);
5116         for(j = 0; j < 20; j++) sprintf(st+2*j, "%02X", digest[j]);
5117         yield = string_cat(yield, &size, &ptr, US st, (int)strlen(st));
5118         continue;
5119         }
5120
5121       /* Convert hex encoding to base64 encoding */
5122
5123       case EOP_HEX2B64:
5124         {
5125         int c = 0;
5126         int b = -1;
5127         uschar *in = sub;
5128         uschar *out = sub;
5129         uschar *enc;
5130
5131         for (enc = sub; *enc != 0; enc++)
5132           {
5133           if (!isxdigit(*enc))
5134             {
5135             expand_string_message = string_sprintf("\"%s\" is not a hex "
5136               "string", sub);
5137             goto EXPAND_FAILED;
5138             }
5139           c++;
5140           }
5141
5142         if ((c & 1) != 0)
5143           {
5144           expand_string_message = string_sprintf("\"%s\" contains an odd "
5145             "number of characters", sub);
5146           goto EXPAND_FAILED;
5147           }
5148
5149         while ((c = *in++) != 0)
5150           {
5151           if (isdigit(c)) c -= '0';
5152           else c = toupper(c) - 'A' + 10;
5153           if (b == -1)
5154             {
5155             b = c << 4;
5156             }
5157           else
5158             {
5159             *out++ = b | c;
5160             b = -1;
5161             }
5162           }
5163
5164         enc = auth_b64encode(sub, out - sub);
5165         yield = string_cat(yield, &size, &ptr, enc, Ustrlen(enc));
5166         continue;
5167         }
5168
5169       /* mask applies a mask to an IP address; for example the result of
5170       ${mask:131.111.10.206/28} is 131.111.10.192/28. */
5171
5172       case EOP_MASK:
5173         {
5174         int count;
5175         uschar *endptr;
5176         int binary[4];
5177         int mask, maskoffset;
5178         int type = string_is_ip_address(sub, &maskoffset);
5179         uschar buffer[64];
5180
5181         if (type == 0)
5182           {
5183           expand_string_message = string_sprintf("\"%s\" is not an IP address",
5184            sub);
5185           goto EXPAND_FAILED;
5186           }
5187
5188         if (maskoffset == 0)
5189           {
5190           expand_string_message = string_sprintf("missing mask value in \"%s\"",
5191             sub);
5192           goto EXPAND_FAILED;
5193           }
5194
5195         mask = Ustrtol(sub + maskoffset + 1, &endptr, 10);
5196
5197         if (*endptr != 0 || mask < 0 || mask > ((type == 4)? 32 : 128))
5198           {
5199           expand_string_message = string_sprintf("mask value too big in \"%s\"",
5200             sub);
5201           goto EXPAND_FAILED;
5202           }
5203
5204         /* Convert the address to binary integer(s) and apply the mask */
5205
5206         sub[maskoffset] = 0;
5207         count = host_aton(sub, binary);
5208         host_mask(count, binary, mask);
5209
5210         /* Convert to masked textual format and add to output. */
5211
5212         yield = string_cat(yield, &size, &ptr, buffer,
5213           host_nmtoa(count, binary, mask, buffer, '.'));
5214         continue;
5215         }
5216
5217       case EOP_ADDRESS:
5218       case EOP_LOCAL_PART:
5219       case EOP_DOMAIN:
5220         {
5221         uschar *error;
5222         int start, end, domain;
5223         uschar *t = parse_extract_address(sub, &error, &start, &end, &domain,
5224           FALSE);
5225         if (t != NULL)
5226           {
5227           if (c != EOP_DOMAIN)
5228             {
5229             if (c == EOP_LOCAL_PART && domain != 0) end = start + domain - 1;
5230             yield = string_cat(yield, &size, &ptr, sub+start, end-start);
5231             }
5232           else if (domain != 0)
5233             {
5234             domain += start;
5235             yield = string_cat(yield, &size, &ptr, sub+domain, end-domain);
5236             }
5237           }
5238         continue;
5239         }
5240
5241       case EOP_ADDRESSES:
5242         {
5243         uschar outsep[2] = { ':', '\0' };
5244         uschar *address, *error;
5245         int save_ptr = ptr;
5246         int start, end, domain;  /* Not really used */
5247
5248         while (isspace(*sub)) sub++;
5249         if (*sub == '>') { *outsep = *++sub; ++sub; }
5250         parse_allow_group = TRUE;
5251
5252         for (;;)
5253           {
5254           uschar *p = parse_find_address_end(sub, FALSE);
5255           uschar saveend = *p;
5256           *p = '\0';
5257           address = parse_extract_address(sub, &error, &start, &end, &domain,
5258             FALSE);
5259           *p = saveend;
5260
5261           /* Add the address to the output list that we are building. This is
5262           done in chunks by searching for the separator character. At the
5263           start, unless we are dealing with the first address of the output
5264           list, add in a space if the new address begins with the separator
5265           character, or is an empty string. */
5266
5267           if (address != NULL)
5268             {
5269             if (ptr != save_ptr && address[0] == *outsep)
5270               yield = string_cat(yield, &size, &ptr, US" ", 1);
5271
5272             for (;;)
5273               {
5274               size_t seglen = Ustrcspn(address, outsep);
5275               yield = string_cat(yield, &size, &ptr, address, seglen + 1);
5276
5277               /* If we got to the end of the string we output one character
5278               too many. */
5279
5280               if (address[seglen] == '\0') { ptr--; break; }
5281               yield = string_cat(yield, &size, &ptr, outsep, 1);
5282               address += seglen + 1;
5283               }
5284
5285             /* Output a separator after the string: we will remove the
5286             redundant final one at the end. */
5287
5288             yield = string_cat(yield, &size, &ptr, outsep, 1);
5289             }
5290
5291           if (saveend == '\0') break;
5292           sub = p + 1;
5293           }
5294
5295         /* If we have generated anything, remove the redundant final
5296         separator. */
5297
5298         if (ptr != save_ptr) ptr--;
5299         parse_allow_group = FALSE;
5300         continue;
5301         }
5302
5303
5304       /* quote puts a string in quotes if it is empty or contains anything
5305       other than alphamerics, underscore, dot, or hyphen.
5306
5307       quote_local_part puts a string in quotes if RFC 2821/2822 requires it to
5308       be quoted in order to be a valid local part.
5309
5310       In both cases, newlines and carriage returns are converted into \n and \r
5311       respectively */
5312
5313       case EOP_QUOTE:
5314       case EOP_QUOTE_LOCAL_PART:
5315       if (arg == NULL)
5316         {
5317         BOOL needs_quote = (*sub == 0);      /* TRUE for empty string */
5318         uschar *t = sub - 1;
5319
5320         if (c == EOP_QUOTE)
5321           {
5322           while (!needs_quote && *(++t) != 0)
5323             needs_quote = !isalnum(*t) && !strchr("_-.", *t);
5324           }
5325         else  /* EOP_QUOTE_LOCAL_PART */
5326           {
5327           while (!needs_quote && *(++t) != 0)
5328             needs_quote = !isalnum(*t) &&
5329               strchr("!#$%&'*+-/=?^_`{|}~", *t) == NULL &&
5330               (*t != '.' || t == sub || t[1] == 0);
5331           }
5332
5333         if (needs_quote)
5334           {
5335           yield = string_cat(yield, &size, &ptr, US"\"", 1);
5336           t = sub - 1;
5337           while (*(++t) != 0)
5338             {
5339             if (*t == '\n')
5340               yield = string_cat(yield, &size, &ptr, US"\\n", 2);
5341             else if (*t == '\r')
5342               yield = string_cat(yield, &size, &ptr, US"\\r", 2);
5343             else
5344               {
5345               if (*t == '\\' || *t == '"')
5346                 yield = string_cat(yield, &size, &ptr, US"\\", 1);
5347               yield = string_cat(yield, &size, &ptr, t, 1);
5348               }
5349             }
5350           yield = string_cat(yield, &size, &ptr, US"\"", 1);
5351           }
5352         else yield = string_cat(yield, &size, &ptr, sub, Ustrlen(sub));
5353         continue;
5354         }
5355
5356       /* quote_lookuptype does lookup-specific quoting */
5357
5358       else
5359         {
5360         int n;
5361         uschar *opt = Ustrchr(arg, '_');
5362
5363         if (opt != NULL) *opt++ = 0;
5364
5365         n = search_findtype(arg, Ustrlen(arg));
5366         if (n < 0)
5367           {
5368           expand_string_message = search_error_message;
5369           goto EXPAND_FAILED;
5370           }
5371
5372         if (lookup_list[n].quote != NULL)
5373           sub = (lookup_list[n].quote)(sub, opt);
5374         else if (opt != NULL) sub = NULL;
5375
5376         if (sub == NULL)
5377           {
5378           expand_string_message = string_sprintf(
5379             "\"%s\" unrecognized after \"${quote_%s\"",
5380             opt, arg);
5381           goto EXPAND_FAILED;
5382           }
5383
5384         yield = string_cat(yield, &size, &ptr, sub, Ustrlen(sub));
5385         continue;
5386         }
5387
5388       /* rx quote sticks in \ before any non-alphameric character so that
5389       the insertion works in a regular expression. */
5390
5391       case EOP_RXQUOTE:
5392         {
5393         uschar *t = sub - 1;
5394         while (*(++t) != 0)
5395           {
5396           if (!isalnum(*t))
5397             yield = string_cat(yield, &size, &ptr, US"\\", 1);
5398           yield = string_cat(yield, &size, &ptr, t, 1);
5399           }
5400         continue;
5401         }
5402
5403       /* RFC 2047 encodes, assuming headers_charset (default ISO 8859-1) as
5404       prescribed by the RFC, if there are characters that need to be encoded */
5405
5406       case EOP_RFC2047:
5407         {
5408         uschar buffer[2048];
5409         uschar *string = parse_quote_2047(sub, Ustrlen(sub), headers_charset,
5410           buffer, sizeof(buffer), FALSE);
5411         yield = string_cat(yield, &size, &ptr, string, Ustrlen(string));
5412         continue;
5413         }
5414
5415       /* RFC 2047 decode */
5416
5417       case EOP_RFC2047D:
5418         {
5419         int len;
5420         uschar *error;
5421         uschar *decoded = rfc2047_decode(sub, check_rfc2047_length,
5422           headers_charset, '?', &len, &error);
5423         if (error != NULL)
5424           {
5425           expand_string_message = error;
5426           goto EXPAND_FAILED;
5427           }
5428         yield = string_cat(yield, &size, &ptr, decoded, len);
5429         continue;
5430         }
5431
5432       /* from_utf8 converts UTF-8 to 8859-1, turning non-existent chars into
5433       underscores */
5434
5435       case EOP_FROM_UTF8:
5436         {
5437         while (*sub != 0)
5438           {
5439           int c;
5440           uschar buff[4];
5441           GETUTF8INC(c, sub);
5442           if (c > 255) c = '_';
5443           buff[0] = c;
5444           yield = string_cat(yield, &size, &ptr, buff, 1);
5445           }
5446         continue;
5447         }
5448
5449       /* escape turns all non-printing characters into escape sequences. */
5450
5451       case EOP_ESCAPE:
5452         {
5453         uschar *t = string_printing(sub);
5454         yield = string_cat(yield, &size, &ptr, t, Ustrlen(t));
5455         continue;
5456         }
5457
5458       /* Handle numeric expression evaluation */
5459
5460       case EOP_EVAL:
5461       case EOP_EVAL10:
5462         {
5463         uschar *save_sub = sub;
5464         uschar *error = NULL;
5465         int n = eval_expr(&sub, (c == EOP_EVAL10), &error, FALSE);
5466         if (error != NULL)
5467           {
5468           expand_string_message = string_sprintf("error in expression "
5469             "evaluation: %s (after processing \"%.*s\")", error, sub-save_sub,
5470               save_sub);
5471           goto EXPAND_FAILED;
5472           }
5473         sprintf(CS var_buffer, "%d", n);
5474         yield = string_cat(yield, &size, &ptr, var_buffer, Ustrlen(var_buffer));
5475         continue;
5476         }
5477
5478       /* Handle time period formating */
5479
5480       case EOP_TIME_EVAL:
5481         {
5482         int n = readconf_readtime(sub, 0, FALSE);
5483         if (n < 0)
5484           {
5485           expand_string_message = string_sprintf("string \"%s\" is not an "
5486             "Exim time interval in \"%s\" operator", sub, name);
5487           goto EXPAND_FAILED;
5488           }
5489         sprintf(CS var_buffer, "%d", n);
5490         yield = string_cat(yield, &size, &ptr, var_buffer, Ustrlen(var_buffer));
5491         continue;
5492         }
5493
5494       case EOP_TIME_INTERVAL:
5495         {
5496         int n;
5497         uschar *t = read_number(&n, sub);
5498         if (*t != 0) /* Not A Number*/
5499           {
5500           expand_string_message = string_sprintf("string \"%s\" is not a "
5501             "positive number in \"%s\" operator", sub, name);
5502           goto EXPAND_FAILED;
5503           }
5504         t = readconf_printtime(n);
5505         yield = string_cat(yield, &size, &ptr, t, Ustrlen(t));
5506         continue;
5507         }
5508
5509       /* Convert string to base64 encoding */
5510
5511       case EOP_STR2B64:
5512         {
5513         uschar *encstr = auth_b64encode(sub, Ustrlen(sub));
5514         yield = string_cat(yield, &size, &ptr, encstr, Ustrlen(encstr));
5515         continue;
5516         }
5517
5518       /* strlen returns the length of the string */
5519
5520       case EOP_STRLEN:
5521         {
5522         uschar buff[24];
5523         (void)sprintf(CS buff, "%d", Ustrlen(sub));
5524         yield = string_cat(yield, &size, &ptr, buff, Ustrlen(buff));
5525         continue;
5526         }
5527
5528       /* length_n or l_n takes just the first n characters or the whole string,
5529       whichever is the shorter;
5530
5531       substr_m_n, and s_m_n take n characters from offset m; negative m take
5532       from the end; l_n is synonymous with s_0_n. If n is omitted in substr it
5533       takes the rest, either to the right or to the left.
5534
5535       hash_n or h_n makes a hash of length n from the string, yielding n
5536       characters from the set a-z; hash_n_m makes a hash of length n, but
5537       uses m characters from the set a-zA-Z0-9.
5538
5539       nhash_n returns a single number between 0 and n-1 (in text form), while
5540       nhash_n_m returns a div/mod hash as two numbers "a/b". The first lies
5541       between 0 and n-1 and the second between 0 and m-1. */
5542
5543       case EOP_LENGTH:
5544       case EOP_L:
5545       case EOP_SUBSTR:
5546       case EOP_S:
5547       case EOP_HASH:
5548       case EOP_H:
5549       case EOP_NHASH:
5550       case EOP_NH:
5551         {
5552         int sign = 1;
5553         int value1 = 0;
5554         int value2 = -1;
5555         int *pn;
5556         int len;
5557         uschar *ret;
5558
5559         if (arg == NULL)
5560           {
5561           expand_string_message = string_sprintf("missing values after %s",
5562             name);
5563           goto EXPAND_FAILED;
5564           }
5565
5566         /* "length" has only one argument, effectively being synonymous with
5567         substr_0_n. */
5568
5569         if (c == EOP_LENGTH || c == EOP_L)
5570           {
5571           pn = &value2;
5572           value2 = 0;
5573           }
5574
5575         /* The others have one or two arguments; for "substr" the first may be
5576         negative. The second being negative means "not supplied". */
5577
5578         else
5579           {
5580           pn = &value1;
5581           if (name[0] == 's' && *arg == '-') { sign = -1; arg++; }
5582           }
5583
5584         /* Read up to two numbers, separated by underscores */
5585
5586         ret = arg;
5587         while (*arg != 0)
5588           {
5589           if (arg != ret && *arg == '_' && pn == &value1)
5590             {
5591             pn = &value2;
5592             value2 = 0;
5593             if (arg[1] != 0) arg++;
5594             }
5595           else if (!isdigit(*arg))
5596             {
5597             expand_string_message =
5598               string_sprintf("non-digit after underscore in \"%s\"", name);
5599             goto EXPAND_FAILED;
5600             }
5601           else *pn = (*pn)*10 + *arg++ - '0';
5602           }
5603         value1 *= sign;
5604
5605         /* Perform the required operation */
5606
5607         ret =
5608           (c == EOP_HASH || c == EOP_H)?
5609              compute_hash(sub, value1, value2, &len) :
5610           (c == EOP_NHASH || c == EOP_NH)?
5611              compute_nhash(sub, value1, value2, &len) :
5612              extract_substr(sub, value1, value2, &len);
5613
5614         if (ret == NULL) goto EXPAND_FAILED;
5615         yield = string_cat(yield, &size, &ptr, ret, len);
5616         continue;
5617         }
5618
5619       /* Stat a path */
5620
5621       case EOP_STAT:
5622         {
5623         uschar *s;
5624         uschar smode[12];
5625         uschar **modetable[3];
5626         int i;
5627         mode_t mode;
5628         struct stat st;
5629
5630         if ((expand_forbid & RDO_EXISTS) != 0)
5631           {
5632           expand_string_message = US"Use of the stat() expansion is not permitted";
5633           goto EXPAND_FAILED;
5634           }
5635
5636         if (stat(CS sub, &st) < 0)
5637           {
5638           expand_string_message = string_sprintf("stat(%s) failed: %s",
5639             sub, strerror(errno));
5640           goto EXPAND_FAILED;
5641           }
5642         mode = st.st_mode;
5643         switch (mode & S_IFMT)
5644           {
5645           case S_IFIFO: smode[0] = 'p'; break;
5646           case S_IFCHR: smode[0] = 'c'; break;
5647           case S_IFDIR: smode[0] = 'd'; break;
5648           case S_IFBLK: smode[0] = 'b'; break;
5649           case S_IFREG: smode[0] = '-'; break;
5650           default: smode[0] = '?'; break;
5651           }
5652
5653         modetable[0] = ((mode & 01000) == 0)? mtable_normal : mtable_sticky;
5654         modetable[1] = ((mode & 02000) == 0)? mtable_normal : mtable_setid;
5655         modetable[2] = ((mode & 04000) == 0)? mtable_normal : mtable_setid;
5656
5657         for (i = 0; i < 3; i++)
5658           {
5659           memcpy(CS(smode + 7 - i*3), CS(modetable[i][mode & 7]), 3);
5660           mode >>= 3;
5661           }
5662
5663         smode[10] = 0;
5664         s = string_sprintf("mode=%04lo smode=%s inode=%ld device=%ld links=%ld "
5665           "uid=%ld gid=%ld size=" OFF_T_FMT " atime=%ld mtime=%ld ctime=%ld",
5666           (long)(st.st_mode & 077777), smode, (long)st.st_ino,
5667           (long)st.st_dev, (long)st.st_nlink, (long)st.st_uid,
5668           (long)st.st_gid, st.st_size, (long)st.st_atime,
5669           (long)st.st_mtime, (long)st.st_ctime);
5670         yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
5671         continue;
5672         }
5673
5674       /* Unknown operator */
5675
5676       default:
5677       expand_string_message =
5678         string_sprintf("unknown expansion operator \"%s\"", name);
5679       goto EXPAND_FAILED;
5680       }
5681     }
5682
5683   /* Handle a plain name. If this is the first thing in the expansion, release
5684   the pre-allocated buffer. If the result data is known to be in a new buffer,
5685   newsize will be set to the size of that buffer, and we can just point at that
5686   store instead of copying. Many expansion strings contain just one reference,
5687   so this is a useful optimization, especially for humungous headers
5688   ($message_headers). */
5689
5690   if (*s++ == '}')
5691     {
5692     int len;
5693     int newsize = 0;
5694     if (ptr == 0)
5695       {
5696       store_reset(yield);
5697       yield = NULL;
5698       size = 0;
5699       }
5700     value = find_variable(name, FALSE, skipping, &newsize);
5701     if (value == NULL)
5702       {
5703       expand_string_message =
5704         string_sprintf("unknown variable in \"${%s}\"", name);
5705       check_variable_error_message(name);
5706       goto EXPAND_FAILED;
5707       }
5708     len = Ustrlen(value);
5709     if (yield == NULL && newsize != 0)
5710       {
5711       yield = value;
5712       size = newsize;
5713       ptr = len;
5714       }
5715     else yield = string_cat(yield, &size, &ptr, value, len);
5716     continue;
5717     }
5718
5719   /* Else there's something wrong */
5720
5721   expand_string_message =
5722     string_sprintf("\"${%s\" is not a known operator (or a } is missing "
5723     "in a variable reference)", name);
5724   goto EXPAND_FAILED;
5725   }
5726
5727 /* If we hit the end of the string when ket_ends is set, there is a missing
5728 terminating brace. */
5729
5730 if (ket_ends && *s == 0)
5731   {
5732   expand_string_message = malformed_header?
5733     US"missing } at end of string - could be header name not terminated by colon"
5734     :
5735     US"missing } at end of string";
5736   goto EXPAND_FAILED;
5737   }
5738
5739 /* Expansion succeeded; yield may still be NULL here if nothing was actually
5740 added to the string. If so, set up an empty string. Add a terminating zero. If
5741 left != NULL, return a pointer to the terminator. */
5742
5743 if (yield == NULL) yield = store_get(1);
5744 yield[ptr] = 0;
5745 if (left != NULL) *left = s;
5746
5747 /* Any stacking store that was used above the final string is no longer needed.
5748 In many cases the final string will be the first one that was got and so there
5749 will be optimal store usage. */
5750
5751 store_reset(yield + ptr + 1);
5752 DEBUG(D_expand)
5753   {
5754   debug_printf("expanding: %.*s\n   result: %s\n", (int)(s - string), string,
5755     yield);
5756   if (skipping) debug_printf("skipping: result is not used\n");
5757   }
5758 return yield;
5759
5760 /* This is the failure exit: easiest to program with a goto. We still need
5761 to update the pointer to the terminator, for cases of nested calls with "fail".
5762 */
5763
5764 EXPAND_FAILED_CURLY:
5765 expand_string_message = malformed_header?
5766   US"missing or misplaced { or } - could be header name not terminated by colon"
5767   :
5768   US"missing or misplaced { or }";
5769
5770 /* At one point, Exim reset the store to yield (if yield was not NULL), but
5771 that is a bad idea, because expand_string_message is in dynamic store. */
5772
5773 EXPAND_FAILED:
5774 if (left != NULL) *left = s;
5775 DEBUG(D_expand)
5776   {
5777   debug_printf("failed to expand: %s\n", string);
5778   debug_printf("   error message: %s\n", expand_string_message);
5779   if (expand_string_forcedfail) debug_printf("failure was forced\n");
5780   }
5781 return NULL;
5782 }
5783
5784
5785 /* This is the external function call. Do a quick check for any expansion
5786 metacharacters, and if there are none, just return the input string.
5787
5788 Argument: the string to be expanded
5789 Returns:  the expanded string, or NULL if expansion failed; if failure was
5790           due to a lookup deferring, search_find_defer will be TRUE
5791 */
5792
5793 uschar *
5794 expand_string(uschar *string)
5795 {
5796 search_find_defer = FALSE;
5797 malformed_header = FALSE;
5798 return (Ustrpbrk(string, "$\\") == NULL)? string :
5799   expand_string_internal(string, FALSE, NULL, FALSE);
5800 }
5801
5802
5803
5804 /*************************************************
5805 *              Expand and copy                   *
5806 *************************************************/
5807
5808 /* Now and again we want to expand a string and be sure that the result is in a
5809 new bit of store. This function does that.
5810
5811 Argument: the string to be expanded
5812 Returns:  the expanded string, always in a new bit of store, or NULL
5813 */
5814
5815 uschar *
5816 expand_string_copy(uschar *string)
5817 {
5818 uschar *yield = expand_string(string);
5819 if (yield == string) yield = string_copy(string);
5820 return yield;
5821 }
5822
5823
5824
5825 /*************************************************
5826 *        Expand and interpret as an integer      *
5827 *************************************************/
5828
5829 /* Expand a string, and convert the result into an integer.
5830
5831 Arguments:
5832   string  the string to be expanded
5833   isplus  TRUE if a non-negative number is expected
5834
5835 Returns:  the integer value, or
5836           -1 for an expansion error               ) in both cases, message in
5837           -2 for an integer interpretation error  ) expand_string_message
5838           expand_string_message is set NULL for an OK integer
5839 */
5840
5841 int
5842 expand_string_integer(uschar *string, BOOL isplus)
5843 {
5844 long int value;
5845 uschar *s = expand_string(string);
5846 uschar *msg = US"invalid integer \"%s\"";
5847 uschar *endptr;
5848
5849 /* If expansion failed, expand_string_message will be set. */
5850
5851 if (s == NULL) return -1;
5852
5853 /* On an overflow, strtol() returns LONG_MAX or LONG_MIN, and sets errno
5854 to ERANGE. When there isn't an overflow, errno is not changed, at least on some
5855 systems, so we set it zero ourselves. */
5856
5857 errno = 0;
5858 expand_string_message = NULL;               /* Indicates no error */
5859 value = strtol(CS s, CSS &endptr, 10);
5860
5861 if (endptr == s)
5862   {
5863   msg = US"integer expected but \"%s\" found";
5864   }
5865 else if (value < 0 && isplus)
5866   {
5867   msg = US"non-negative integer expected but \"%s\" found";
5868   }
5869 else
5870   {
5871   /* Ensure we can cast this down to an int */
5872   if (value > INT_MAX  || value < INT_MIN) errno = ERANGE;
5873
5874   if (errno != ERANGE)
5875     {
5876     if (tolower(*endptr) == 'k')
5877       {
5878       if (value > INT_MAX/1024 || value < INT_MIN/1024) errno = ERANGE;
5879         else value *= 1024;
5880       endptr++;
5881       }
5882     else if (tolower(*endptr) == 'm')
5883       {
5884       if (value > INT_MAX/(1024*1024) || value < INT_MIN/(1024*1024))
5885         errno = ERANGE;
5886       else value *= 1024*1024;
5887       endptr++;
5888       }
5889     }
5890   if (errno == ERANGE)
5891     msg = US"absolute value of integer \"%s\" is too large (overflow)";
5892   else
5893     {
5894     while (isspace(*endptr)) endptr++;
5895     if (*endptr == 0) return (int)value;
5896     }
5897   }
5898
5899 expand_string_message = string_sprintf(CS msg, s);
5900 return -2;
5901 }
5902
5903
5904 /*************************************************
5905 **************************************************
5906 *             Stand-alone test program           *
5907 **************************************************
5908 *************************************************/
5909
5910 #ifdef STAND_ALONE
5911
5912
5913 BOOL
5914 regex_match_and_setup(const pcre *re, uschar *subject, int options, int setup)
5915 {
5916 int ovector[3*(EXPAND_MAXN+1)];
5917 int n = pcre_exec(re, NULL, subject, Ustrlen(subject), 0, PCRE_EOPT|options,
5918   ovector, sizeof(ovector)/sizeof(int));
5919 BOOL yield = n >= 0;
5920 if (n == 0) n = EXPAND_MAXN + 1;
5921 if (yield)
5922   {
5923   int nn;
5924   expand_nmax = (setup < 0)? 0 : setup + 1;
5925   for (nn = (setup < 0)? 0 : 2; nn < n*2; nn += 2)
5926     {
5927     expand_nstring[expand_nmax] = subject + ovector[nn];
5928     expand_nlength[expand_nmax++] = ovector[nn+1] - ovector[nn];
5929     }
5930   expand_nmax--;
5931   }
5932 return yield;
5933 }
5934
5935
5936 int main(int argc, uschar **argv)
5937 {
5938 int i;
5939 uschar buffer[1024];
5940
5941 debug_selector = D_v;
5942 debug_file = stderr;
5943 debug_fd = fileno(debug_file);
5944 big_buffer = malloc(big_buffer_size);
5945
5946 for (i = 1; i < argc; i++)
5947   {
5948   if (argv[i][0] == '+')
5949     {
5950     debug_trace_memory = 2;
5951     argv[i]++;
5952     }
5953   if (isdigit(argv[i][0]))
5954     debug_selector = Ustrtol(argv[i], NULL, 0);
5955   else
5956     if (Ustrspn(argv[i], "abcdefghijklmnopqrtsuvwxyz0123456789-.:/") ==
5957         Ustrlen(argv[i]))
5958       {
5959       #ifdef LOOKUP_LDAP
5960       eldap_default_servers = argv[i];
5961       #endif
5962       #ifdef LOOKUP_MYSQL
5963       mysql_servers = argv[i];
5964       #endif
5965       #ifdef LOOKUP_PGSQL
5966       pgsql_servers = argv[i];
5967       #endif
5968       }
5969   #ifdef EXIM_PERL
5970   else opt_perl_startup = argv[i];
5971   #endif
5972   }
5973
5974 printf("Testing string expansion: debug_level = %d\n\n", debug_level);
5975
5976 expand_nstring[1] = US"string 1....";
5977 expand_nlength[1] = 8;
5978 expand_nmax = 1;
5979
5980 #ifdef EXIM_PERL
5981 if (opt_perl_startup != NULL)
5982   {
5983   uschar *errstr;
5984   printf("Starting Perl interpreter\n");
5985   errstr = init_perl(opt_perl_startup);
5986   if (errstr != NULL)
5987     {
5988     printf("** error in perl_startup code: %s\n", errstr);
5989     return EXIT_FAILURE;
5990     }
5991   }
5992 #endif /* EXIM_PERL */
5993
5994 while (fgets(buffer, sizeof(buffer), stdin) != NULL)
5995   {
5996   void *reset_point = store_get(0);
5997   uschar *yield = expand_string(buffer);
5998   if (yield != NULL)
5999     {
6000     printf("%s\n", yield);
6001     store_reset(reset_point);
6002     }
6003   else
6004     {
6005     if (search_find_defer) printf("search_find deferred\n");
6006     printf("Failed: %s\n", expand_string_message);
6007     if (expand_string_forcedfail) printf("Forced failure\n");
6008     printf("\n");
6009     }
6010   }
6011
6012 search_tidyup();
6013
6014 return 0;
6015 }
6016
6017 #endif
6018
6019 /* End of expand.c */