src/src/rda.c

   1 /* $Cambridge: exim/src/src/rda.c,v 1.4 2005/02/17 11:58:26 ph10 Exp $ */
   2
   3 /*************************************************
   4 *     Exim - an Internet mail transport agent    *
   5 *************************************************/
   6
   7 /* Copyright (c) University of Cambridge 1995 - 2005 */
   8 /* See the file NOTICE for conditions of use and distribution. */
   9
  10 /* This module contains code for extracting addresses from a forwarding list
  11 (from an alias or forward file) or by running the filter interpreter. It may do
  12 this in a sub-process if a uid/gid are supplied. */
  13
  14
  15 #include "exim.h"
  16
  17 enum { FILE_EXIST, FILE_NOT_EXIST, FILE_EXIST_UNCLEAR };
  18
  19 #define REPLY_EXISTS    0x01
  20 #define REPLY_EXPAND    0x02
  21 #define REPLY_RETURN    0x04
  22
  23
  24 /*************************************************
  25 *         Check string for filter program        *
  26 *************************************************/
  27
  28 /* This function checks whether a string is actually a filter program. The rule
  29 is that it must start with "# Exim filter ..." (any capitalization, spaces
  30 optional). It is envisaged that in future, other kinds of filter may be
  31 implemented. That's why it is implemented the way it is. The function is global
  32 because it is also called from filter.c when checking filters.
  33
  34 Argument:  the string
  35
  36 Returns:   FILTER_EXIM    if it starts with "# Exim filter"
  37            FILTER_SIEVE   if it starts with "# Sieve filter"
  38            FILTER_FORWARD otherwise
  39 */
  40
  41 /* This is an auxiliary function for matching a tag. */
  42
  43 static BOOL
  44 match_tag(const uschar *s, const uschar *tag)
  45 {
  46 for (; *tag != 0; s++, tag++)
  47   {
  48   if (*tag == ' ')
  49     {
  50     while (*s == ' ' || *s == '\t') s++;
  51     s--;
  52     }
  53   else if (tolower(*s) != tolower(*tag)) break;
  54   }
  55 return (*tag == 0);
  56 }
  57
  58 /* This is the real function. It should be easy to add checking different
  59 tags for other types of filter. */
  60
  61 int
  62 rda_is_filter(const uschar *s)
  63 {
  64 while (isspace(*s)) s++;     /* Skips initial blank lines */
  65 if (match_tag(s, CUS"# exim filter")) return FILTER_EXIM;
  66   else if (match_tag(s, CUS"# sieve filter")) return FILTER_SIEVE;
  67     else return FILTER_FORWARD;
  68 }
  69
  70
  71
  72
  73 /*************************************************
  74 *         Check for existence of file            *
  75 *************************************************/
  76
  77 /* First of all, we stat the file. If this fails, we try to stat the enclosing
  78 directory, because a file in an unmounted NFS directory will look the same as a
  79 non-existent file. It seems that in Solaris 2.6, statting an entry in an
  80 indirect map that is currently unmounted does not cause the mount to happen.
  81 Instead, dummy data is returned, which defeats the whole point of this test.
  82 However, if a stat() is done on some object inside the directory, such as the
  83 "." back reference to itself, then the mount does occur. If an NFS host is
  84 taken offline, it is possible for the stat() to get stuck until it comes back.
  85 To guard against this, stick a timer round it. If we can't access the "."
  86 inside the directory, try the plain directory, just in case that helps.
  87
  88 Argument:
  89   filename   the file name
  90   error      for message on error
  91
  92 Returns:     FILE_EXIST          the file exists
  93              FILE_NOT_EXIST      the file does not exist
  94              FILE_EXIST_UNCLEAR  cannot determine existence
  95 */
  96
  97 static int
  98 rda_exists(uschar *filename, uschar **error)
  99 {
 100 int rc, saved_errno;
 101 uschar *slash;
 102 struct stat statbuf;
 103
 104 if ((rc = Ustat(filename, &statbuf)) >= 0) return FILE_EXIST;
 105 saved_errno = errno;
 106
 107 Ustrncpy(big_buffer, filename, big_buffer_size - 3);
 108 sigalrm_seen = FALSE;
 109
 110 if (saved_errno == ENOENT)
 111   {
 112   slash = Ustrrchr(big_buffer, '/');
 113   Ustrcpy(slash+1, ".");
 114
 115   alarm(30);
 116   rc = Ustat(big_buffer, &statbuf);
 117   if (rc != 0 && errno == EACCES && !sigalrm_seen)
 118     {
 119     *slash = 0;
 120     rc = Ustat(big_buffer, &statbuf);
 121     }
 122   saved_errno = errno;
 123   alarm(0);
 124
 125   DEBUG(D_route) debug_printf("stat(%s)=%d\n", big_buffer, rc);
 126   }
 127
 128 if (sigalrm_seen || rc != 0)
 129   {
 130   *error = string_sprintf("failed to stat %s (%s)", big_buffer,
 131     sigalrm_seen? "timeout" : strerror(saved_errno));
 132   return FILE_EXIST_UNCLEAR;
 133   }
 134
 135 *error = string_sprintf("%s does not exist", filename);
 136 DEBUG(D_route) debug_printf("%s\n", *error);
 137 return FILE_NOT_EXIST;
 138 }
 139
 140
 141
 142 /*************************************************
 143 *     Get forwarding list from a file            *
 144 *************************************************/
 145
 146 /* Open a file and read its entire contents into a block of memory. Certain
 147 opening errors are optionally treated the same as "file does not exist".
 148
 149 ENOTDIR means that something along the line is not a directory: there are
 150 installations that set home directories to be /dev/null for non-login accounts
 151 but in normal circumstances this indicates some kind of configuration error.
 152
 153 EACCES means there's a permissions failure. Some users turn off read permission
 154 on a .forward file to suspend forwarding, but this is probably an error in any
 155 kind of mailing list processing.
 156
 157 The redirect block that contains the file name also contains constraints such
 158 as who may own the file, and mode bits that must not be set. This function is
 159
 160 Arguments:
 161   rdata       rdirect block, containing file name and constraints
 162   options     for the RDO_ENOTDIR and RDO_EACCES options
 163   error       where to put an error message
 164   yield       what to return from rda_interpret on error
 165
 166 Returns:      pointer to string in store; NULL on error
 167 */
 168
 169 static uschar *
 170 rda_get_file_contents(redirect_block *rdata, int options, uschar **error,
 171   int *yield)
 172 {
 173 FILE *fwd;
 174 uschar *filebuf;
 175 uschar *filename = rdata->string;
 176 BOOL uid_ok = !rdata->check_owner;
 177 BOOL gid_ok = !rdata->check_group;
 178 struct stat statbuf;
 179
 180 /* Attempt to open the file. If it appears not to exist, check up on the
 181 containing directory by statting it. If the directory does not exist, we treat
 182 this situation as an error (which will cause delivery to defer); otherwise we
 183 pass back FF_NONEXIST, which causes the redirect router to decline.
 184
 185 However, if the ignore_enotdir option is set (to ignore "something on the
 186 path is not a directory" errors), the right behaviour seems to be not to do the
 187 directory test. */
 188
 189 fwd = Ufopen(filename, "rb");
 190 if (fwd == NULL)
 191   {
 192   switch(errno)
 193     {
 194     case ENOENT:          /* File does not exist */
 195     DEBUG(D_route) debug_printf("%s does not exist\n%schecking parent directory\n",
 196       filename,
 197       ((options & RDO_ENOTDIR) != 0)? "ignore_enotdir set => skip " : "");
 198     *yield = (((options & RDO_ENOTDIR) != 0) ||
 199               rda_exists(filename, error) == FILE_NOT_EXIST)?
 200       FF_NONEXIST : FF_ERROR;
 201     return NULL;
 202
 203     case ENOTDIR:         /* Something on the path isn't a directory */
 204     if ((options & RDO_ENOTDIR) == 0) goto DEFAULT_ERROR;
 205     DEBUG(D_route) debug_printf("non-directory on path %s: file assumed not to "
 206       "exist\n", filename);
 207     *yield = FF_NONEXIST;
 208     return NULL;
 209
 210     case EACCES:           /* Permission denied */
 211     if ((options & RDO_EACCES) == 0) goto DEFAULT_ERROR;
 212     DEBUG(D_route) debug_printf("permission denied for %s: file assumed not to "
 213       "exist\n", filename);
 214     *yield = FF_NONEXIST;
 215     return NULL;
 216
 217     DEFAULT_ERROR:
 218     default:
 219     *error = string_open_failed(errno, "%s", filename);
 220     *yield = FF_ERROR;
 221     return NULL;
 222     }
 223   }
 224
 225 /* Check that we have a regular file. */
 226
 227 if (fstat(fileno(fwd), &statbuf) != 0)
 228   {
 229   *error = string_sprintf("failed to stat %s: %s", filename, strerror(errno));
 230   goto ERROR_RETURN;
 231   }
 232
 233 if ((statbuf.st_mode & S_IFMT) != S_IFREG)
 234   {
 235   *error = string_sprintf("%s is not a regular file", filename);
 236   goto ERROR_RETURN;
 237   }
 238
 239 /* Check for unwanted mode bits */
 240
 241 if ((statbuf.st_mode & rdata->modemask) != 0)
 242   {
 243   *error = string_sprintf("bad mode (0%o) for %s: 0%o bit(s) unexpected",
 244     statbuf.st_mode, filename, statbuf.st_mode & rdata->modemask);
 245   goto ERROR_RETURN;
 246   }
 247
 248 /* Check the file owner and file group if required to do so. */
 249
 250 if (!uid_ok)
 251   {
 252   if (rdata->pw != NULL && statbuf.st_uid == rdata->pw->pw_uid)
 253     uid_ok = TRUE;
 254   else if (rdata->owners != NULL)
 255     {
 256     int i;
 257     for (i = 1; i <= (int)(rdata->owners[0]); i++)
 258       if (rdata->owners[i] == statbuf.st_uid) { uid_ok = TRUE; break; }
 259     }
 260   }
 261
 262 if (!gid_ok)
 263   {
 264   if (rdata->pw != NULL && statbuf.st_gid == rdata->pw->pw_gid)
 265     gid_ok = TRUE;
 266   else if (rdata->owngroups != NULL)
 267     {
 268     int i;
 269     for (i = 1; i <= (int)(rdata->owngroups[0]); i++)
 270       if (rdata->owngroups[i] == statbuf.st_gid) { gid_ok = TRUE; break; }
 271     }
 272   }
 273
 274 if (!uid_ok || !gid_ok)
 275   {
 276   *error = string_sprintf("bad %s for %s", uid_ok? "group" : "owner", filename);
 277   goto ERROR_RETURN;
 278   }
 279
 280 /* Put an upper limit on the size of the file, just to stop silly people
 281 feeding in ridiculously large files, which can easily be created by making
 282 files that have holes in them. */
 283
 284 if (statbuf.st_size > MAX_FILTER_SIZE)
 285   {
 286   *error = string_sprintf("%s is too big (max %d)", filename, MAX_FILTER_SIZE);
 287   goto ERROR_RETURN;
 288   }
 289
 290 /* Read the file in one go in order to minimize the time we have it open. */
 291
 292 filebuf = store_get(statbuf.st_size + 1);
 293
 294 if (fread(filebuf, 1, statbuf.st_size, fwd) != statbuf.st_size)
 295   {
 296   *error = string_sprintf("error while reading %s: %s",
 297     filename, strerror(errno));
 298   goto ERROR_RETURN;
 299   }
 300 filebuf[statbuf.st_size] = 0;
 301
 302 /* Don't pass statbuf.st_size directly to debug_printf. On some systems it
 303 is a long, which may not be the same as an int. */
 304
 305 DEBUG(D_route)
 306   {
 307   int size = (int)statbuf.st_size;
 308   debug_printf("%d bytes read from %s\n", size, filename);
 309   }
 310
 311 fclose(fwd);
 312 return filebuf;
 313
 314 /* Return an error: the string is already set up. */
 315
 316 ERROR_RETURN:
 317 *yield = FF_ERROR;
 318 fclose(fwd);
 319 return NULL;
 320 }
 321
 322
 323
 324 /*************************************************
 325 *      Extract info from list or filter          *
 326 *************************************************/
 327
 328 /* This function calls the appropriate function to extract addresses from a
 329 forwarding list, or to run a filter file and get addresses from there.
 330
 331 Arguments:
 332   rdata                     the redirection block
 333   options                   the options bits
 334   include_directory         restrain to this directory
 335   sieve_vacation_directory  passed to sieve_interpret
 336   generated                 where to hang generated addresses
 337   error                     for error messages
 338   eblockp                   for details of skipped syntax errors
 339                               (NULL => no skip)
 340   filtertype                set to the filter type:
 341                               FILTER_FORWARD => a traditional .forward file
 342                               FILTER_EXIM    => an Exim filter file
 343                               FILTER_SIEVE   => a Sieve filter file
 344                             a system filter is always forced to be FILTER_EXIM
 345
 346 Returns:                    a suitable return for rda_interpret()
 347 */
 348
 349 static int
 350 rda_extract(redirect_block *rdata, int options, uschar *include_directory,
 351   uschar *sieve_vacation_directory, address_item **generated, uschar **error,
 352   error_block **eblockp, int *filtertype)
 353 {
 354 uschar *data;
 355
 356 if (rdata->isfile)
 357   {
 358   int yield;
 359   data = rda_get_file_contents(rdata, options, error, &yield);
 360   if (data == NULL) return yield;
 361   }
 362 else data = rdata->string;
 363
 364 *filtertype = system_filtering? FILTER_EXIM : rda_is_filter(data);
 365
 366 /* Filter interpretation is done by a general function that is also called from
 367 the filter testing option (-bf). There are two versions: one for Exim filtering
 368 and one for Sieve filtering. Several features of string expansion may be locked
 369 out at sites that don't trust users. This is done by setting flags in
 370 expand_forbid that the expander inspects. */
 371
 372 if (*filtertype != FILTER_FORWARD)
 373   {
 374   int frc;
 375   int old_expand_forbid = expand_forbid;
 376
 377   DEBUG(D_route) debug_printf("data is %s filter program\n",
 378     (*filtertype == FILTER_EXIM)? "an Exim" : "a Sieve");
 379
 380   /* RDO_FILTER is an "allow" bit */
 381
 382   if ((options & RDO_FILTER) == 0)
 383     {
 384     *error = US"filtering not enabled";
 385     return FF_ERROR;
 386     }
 387
 388   expand_forbid =
 389     (expand_forbid & ~RDO_FILTER_EXPANSIONS) |
 390     (options & RDO_FILTER_EXPANSIONS);
 391
 392   /* RDO_{EXIM,SIEVE}_FILTER are forbid bits */
 393
 394   if (*filtertype == FILTER_EXIM)
 395     {
 396     if ((options & RDO_EXIM_FILTER) != 0)
 397       {
 398       *error = US"Exim filtering not enabled";
 399       return FF_ERROR;
 400       }
 401     frc = filter_interpret(data, options, generated, error);
 402     }
 403   else
 404     {
 405     if ((options & RDO_SIEVE_FILTER) != 0)
 406       {
 407       *error = US"Sieve filtering not enabled";
 408       return FF_ERROR;
 409       }
 410     frc = sieve_interpret(data, options, sieve_vacation_directory, generated,
 411       error);
 412     }
 413
 414   expand_forbid = old_expand_forbid;
 415   return frc;
 416   }
 417
 418 /* Not a filter script */
 419
 420 DEBUG(D_route) debug_printf("file is not a filter file\n");
 421
 422 return parse_forward_list(data,
 423   options,                           /* specials that are allowed */
 424   generated,                         /* where to hang them */
 425   error,                             /* for errors */
 426   deliver_domain,                    /* to qualify \name */
 427   include_directory,                 /* restrain to directory */
 428   eblockp);                          /* for skipped syntax errors */
 429 }
 430
 431
 432
 433
 434 /*************************************************
 435 *         Write string down pipe                 *
 436 *************************************************/
 437
 438 /* This function is used for tranferring a string down a pipe between
 439 processes. If the pointer is NULL, a length of zero is written.
 440
 441 Arguments:
 442   fd         the pipe
 443   s          the string
 444
 445 Returns:     nothing
 446 */
 447
 448 static void
 449 rda_write_string(int fd, uschar *s)
 450 {
 451 int len = (s == NULL)? 0 : Ustrlen(s) + 1;
 452 write(fd, &len, sizeof(int));
 453 if (s != NULL) write(fd, s, len);
 454 }
 455
 456
 457
 458 /*************************************************
 459 *          Read string from pipe                 *
 460 *************************************************/
 461
 462 /* This function is used for receiving a string from a pipe.
 463
 464 Arguments:
 465   fd         the pipe
 466   sp         where to put the string
 467
 468 Returns:     FALSE if data missing
 469 */
 470
 471 static BOOL
 472 rda_read_string(int fd, uschar **sp)
 473 {
 474 int len;
 475
 476 if (read(fd, &len, sizeof(int)) != sizeof(int)) return FALSE;
 477 if (len == 0) *sp = NULL; else
 478   {
 479   *sp = store_get(len);
 480   if (read(fd, *sp, len) != len) return FALSE;
 481   }
 482 return TRUE;
 483 }
 484
 485
 486
 487 /*************************************************
 488 *         Interpret forward list or filter       *
 489 *************************************************/
 490
 491 /* This function is passed a forward list string (unexpanded) or the name of a
 492 file (unexpanded) whose contents are the forwarding list. The list may in fact
 493 be a filter program if it starts with "#Exim filter" or "#Sieve filter". Other
 494 types of filter, with different inital tag strings, may be introduced in due
 495 course.
 496
 497 The job of the function is to process the forwarding list or filter. It is
 498 pulled out into this separate function, because it is used for system filter
 499 files as well as from the redirect router.
 500
 501 If the function is given a uid/gid, it runs a subprocess that passes the
 502 results back via a pipe. This provides security for things like :include:s in
 503 users' .forward files, and "logwrite" calls in users' filter files. A
 504 sub-process is NOT used when:
 505
 506   . No uid/gid is provided
 507   . The input is a string which is not a filter string, and does not contain
 508     :include:
 509   . The input is a file whose non-existence can be detected in the main
 510     process (which is usually running as root).
 511
 512 Arguments:
 513   rdata                     redirect data (file + constraints, or data string)
 514   options                   options to pass to the extraction functions,
 515                               plus ENOTDIR and EACCES handling bits
 516   include_directory         restrain :include: to this directory
 517   sieve_vacation_directory  directory passed to sieve_interpret()
 518   ugid                      uid/gid to run under - if NULL, no change
 519   generated                 where to hang generated addresses, initially NULL
 520   error                     pointer for error message
 521   eblockp                   for skipped syntax errors; NULL if no skipping
 522   filtertype                set to the type of file:
 523                               FILTER_FORWARD => traditional .forward file
 524                               FILTER_EXIM    => an Exim filter file
 525                               FILTER_SIEVE   => a Sieve filter file
 526                             a system filter is always forced to be FILTER_EXIM
 527   rname                     router name for error messages in the format
 528                               "xxx router" or "system filter"
 529
 530 Returns:        values from extraction function, or FF_NONEXIST:
 531                   FF_DELIVERED     success, a significant action was taken
 532                   FF_NOTDELIVERED  success, no significant action
 533                   FF_BLACKHOLE     :blackhole:
 534                   FF_DEFER         defer requested
 535                   FF_FAIL          fail requested
 536                   FF_INCLUDEFAIL   some problem with :include:
 537                   FF_FREEZE        freeze requested
 538                   FF_ERROR         there was a problem
 539                   FF_NONEXIST      the file does not exist
 540 */
 541
 542 int
 543 rda_interpret(redirect_block *rdata, int options, uschar *include_directory,
 544   uschar *sieve_vacation_directory, ugid_block *ugid, address_item **generated,
 545   uschar **error, error_block **eblockp, int *filtertype, uschar *rname)
 546 {
 547 int fd, rc, pfd[2];
 548 int yield, status;
 549 BOOL had_disaster = FALSE;
 550 pid_t pid;
 551 uschar *data;
 552 uschar *readerror = US"";
 553 void (*oldsignal)(int);
 554
 555 DEBUG(D_route) debug_printf("rda_interpret (%s): %s\n",
 556   (rdata->isfile)? "file" : "string", rdata->string);
 557
 558 /* Do the expansions of the file name or data first, while still privileged. */
 559
 560 data = expand_string(rdata->string);
 561 if (data == NULL)
 562   {
 563   if (expand_string_forcedfail) return FF_NOTDELIVERED;
 564   *error = string_sprintf("failed to expand \"%s\": %s", rdata->string,
 565     expand_string_message);
 566   return FF_ERROR;
 567   }
 568 rdata->string = data;
 569
 570 DEBUG(D_route) debug_printf("expanded: %s\n", data);
 571
 572 if (rdata->isfile && data[0] != '/')
 573   {
 574   *error = string_sprintf("\"%s\" is not an absolute path", data);
 575   return FF_ERROR;
 576   }
 577
 578 /* If no uid/gid are supplied, or if we have a data string which does not start
 579 with #Exim filter or #Sieve filter, and does not contain :include:, do all the
 580 work in this process. Note that for a system filter, we always have a file, so
 581 the work is done in this process only if no user is supplied. */
 582
 583 if (!ugid->uid_set ||                         /* Either there's no uid, or */
 584     (!rdata->isfile &&                        /* We've got the data, and */
 585      rda_is_filter(data) == FILTER_FORWARD && /* It's not a filter script, */
 586      Ustrstr(data, ":include:") == NULL))     /* and there's no :include: */
 587   {
 588   return rda_extract(rdata, options, include_directory,
 589     sieve_vacation_directory, generated, error, eblockp, filtertype);
 590   }
 591
 592 /* We need to run the processing code in a sub-process. However, if we can
 593 determine the non-existence of a file first, we can decline without having to
 594 create the sub-process. */
 595
 596 if (rdata->isfile && rda_exists(data, error) == FILE_NOT_EXIST)
 597   return FF_NONEXIST;
 598
 599 /* If the file does exist, or we can't tell (non-root mounted NFS directory)
 600 we have to create the subprocess to do everything as the given user. The
 601 results of processing are passed back via a pipe. */
 602
 603 if (pipe(pfd) != 0)
 604   log_write(0, LOG_MAIN|LOG_PANIC_DIE, "creation of pipe for filter or "
 605     ":include: failed for %s: %s", rname, strerror(errno));
 606
 607 /* Ensure that SIGCHLD is set to SIG_DFL before forking, so that the child
 608 process can be waited for. We sometimes get here with it set otherwise. Save
 609 the old state for resetting on the wait. */
 610
 611 oldsignal = signal(SIGCHLD, SIG_DFL);
 612 if ((pid = fork()) == 0)
 613   {
 614   header_line *waslast = header_last;   /* Save last header */
 615
 616   fd = pfd[pipe_write];
 617   close(pfd[pipe_read]);
 618   exim_setugid(ugid->uid, ugid->gid, FALSE, rname);
 619
 620   /* Addresses can get rewritten in filters; if we are not root or the exim
 621   user (and we probably are not), turn off rewrite logging, because we cannot
 622   write to the log now. */
 623
 624   if (ugid->uid != root_uid && ugid->uid != exim_uid)
 625     {
 626     DEBUG(D_rewrite) debug_printf("turned off address rewrite logging (not "
 627       "root or exim in this process)\n");
 628     log_write_selector &= ~L_address_rewrite;
 629     }
 630
 631   /* Now do the business */
 632
 633   yield = rda_extract(rdata, options, include_directory,
 634     sieve_vacation_directory, generated, error, eblockp, filtertype);
 635
 636   /* Pass back whether it was a filter, and the return code and any overall
 637   error text via the pipe. */
 638
 639   write(fd, filtertype, sizeof(int));
 640   write(fd, &yield, sizeof(int));
 641   rda_write_string(fd, *error);
 642
 643   /* Pass back the contents of any syntax error blocks if we have a pointer */
 644
 645   if (eblockp != NULL)
 646     {
 647     error_block *ep;
 648     for (ep = *eblockp; ep != NULL; ep = ep->next)
 649       {
 650       rda_write_string(fd, ep->text1);
 651       rda_write_string(fd, ep->text2);
 652       }
 653     rda_write_string(fd, NULL);    /* Indicates end of eblocks */
 654     }
 655
 656   /* If this is a system filter, we have to pass back the numbers of any
 657   original header lines that were removed, and then any header lines that were
 658   added but not subsequently removed. */
 659
 660   if (system_filtering)
 661     {
 662     int i = 0;
 663     header_line *h;
 664     for (h = header_list; h != waslast->next; i++, h = h->next)
 665       {
 666       if (h->type == htype_old) write(fd, &i, sizeof(i));
 667       }
 668     i = -1;
 669     write(fd, &i, sizeof(i));
 670
 671     while (waslast != header_last)
 672       {
 673       waslast = waslast->next;
 674       if (waslast->type != htype_old)
 675         {
 676         rda_write_string(fd, waslast->text);
 677         write(fd, &(waslast->type), sizeof(waslast->type));
 678         }
 679       }
 680     rda_write_string(fd, NULL);    /* Indicates end of added headers */
 681     }
 682
 683   /* Write the contents of the $n variables */
 684
 685   write(fd, filter_n, sizeof(filter_n));
 686
 687   /* If the result was DELIVERED or NOTDELIVERED, we pass back the generated
 688   addresses, and their associated information, through the pipe. This is
 689   just tedious, but it seems to be the only safe way. We do this also for
 690   FAIL and FREEZE, because a filter is allowed to set up deliveries that
 691   are honoured before freezing or failing. */
 692
 693   if (yield == FF_DELIVERED || yield == FF_NOTDELIVERED ||
 694       yield == FF_FAIL || yield == FF_FREEZE)
 695     {
 696     address_item *addr;
 697     for (addr = *generated; addr != NULL; addr = addr->next)
 698       {
 699       int reply_options = 0;
 700
 701       rda_write_string(fd, addr->address);
 702       write(fd, &(addr->mode), sizeof(addr->mode));
 703       write(fd, &(addr->flags), sizeof(addr->flags));
 704       rda_write_string(fd, addr->p.errors_address);
 705
 706       if (addr->pipe_expandn != NULL)
 707         {
 708         uschar **pp;
 709         for (pp = addr->pipe_expandn; *pp != NULL; pp++)
 710           rda_write_string(fd, *pp);
 711         }
 712       rda_write_string(fd, NULL);
 713
 714       if (addr->reply == NULL)
 715         write(fd, &reply_options, sizeof(int));    /* 0 means no reply */
 716       else
 717         {
 718         reply_options |= REPLY_EXISTS;
 719         if (addr->reply->file_expand) reply_options |= REPLY_EXPAND;
 720         if (addr->reply->return_message) reply_options |= REPLY_RETURN;
 721         write(fd, &reply_options, sizeof(int));
 722         write(fd, &(addr->reply->expand_forbid), sizeof(int));
 723         write(fd, &(addr->reply->once_repeat), sizeof(time_t));
 724         rda_write_string(fd, addr->reply->to);
 725         rda_write_string(fd, addr->reply->cc);
 726         rda_write_string(fd, addr->reply->bcc);
 727         rda_write_string(fd, addr->reply->from);
 728         rda_write_string(fd, addr->reply->reply_to);
 729         rda_write_string(fd, addr->reply->subject);
 730         rda_write_string(fd, addr->reply->headers);
 731         rda_write_string(fd, addr->reply->text);
 732         rda_write_string(fd, addr->reply->file);
 733         rda_write_string(fd, addr->reply->logfile);
 734         rda_write_string(fd, addr->reply->oncelog);
 735         }
 736       }
 737
 738     rda_write_string(fd, NULL);   /* Marks end of addresses */
 739     }
 740
 741   /* OK, this process is now done. Must use _exit() and not exit() !! */
 742
 743   close(fd);
 744   _exit(0);
 745   }
 746
 747 /* Back in the main process: panic if the fork did not succeed. */
 748
 749 if (pid < 0)
 750   log_write(0, LOG_MAIN|LOG_PANIC_DIE, "fork failed for %s", rname);
 751
 752 /* Read the pipe to get the data from the filter/forward. Our copy of the
 753 writing end must be closed first, as otherwise read() won't return zero on an
 754 empty pipe. Afterwards, close the reading end. */
 755
 756 close(pfd[pipe_write]);
 757
 758 /* Read initial data, including yield and contents of *error */
 759
 760 fd = pfd[pipe_read];
 761 if (read(fd, filtertype, sizeof(int)) != sizeof(int) ||
 762     read(fd, &yield, sizeof(int)) != sizeof(int) ||
 763     !rda_read_string(fd, error)) goto DISASTER;
 764
 765 DEBUG(D_route)
 766   debug_printf("rda_interpret: subprocess yield=%d error=%s\n", yield, *error);
 767
 768 /* Read the contents of any syntax error blocks if we have a pointer */
 769
 770 if (eblockp != NULL)
 771   {
 772   uschar *s;
 773   error_block *e;
 774   error_block **p = eblockp;
 775   for (;;)
 776     {
 777     if (!rda_read_string(fd, &s)) goto DISASTER;
 778     if (s == NULL) break;
 779     e = store_get(sizeof(error_block));
 780     e->next = NULL;
 781     e->text1 = s;
 782     if (!rda_read_string(fd, &s)) goto DISASTER;
 783     e->text2 = s;
 784     *p = e;
 785     p = &(e->next);
 786     }
 787   }
 788
 789 /* If this is a system filter, read the identify of any original header lines
 790 that were removed, and then read data for any new ones that were added. */
 791
 792 if (system_filtering)
 793   {
 794   int hn = 0;
 795   header_line *h = header_list;
 796
 797   for (;;)
 798     {
 799     int n;
 800     if (read(fd, &n, sizeof(int)) != sizeof(int)) goto DISASTER;
 801     if (n < 0) break;
 802     while (hn < n)
 803       {
 804       hn++;
 805       h = h->next;
 806       if (h == NULL) goto DISASTER_NO_HEADER;
 807       }
 808     h->type = htype_old;
 809     }
 810
 811   for (;;)
 812     {
 813     uschar *s;
 814     int type;
 815     if (!rda_read_string(fd, &s)) goto DISASTER;
 816     if (s == NULL) break;
 817     if (read(fd, &type, sizeof(type)) != sizeof(type)) goto DISASTER;
 818     header_add(type, "%s", s);
 819     }
 820   }
 821
 822 /* Read the values of the $n variables */
 823
 824 if (read(fd, filter_n, sizeof(filter_n)) != sizeof(filter_n)) goto DISASTER;
 825
 826 /* If the yield is DELIVERED, NOTDELIVERED, FAIL, or FREEZE there may follow
 827 addresses and data to go with them. Keep them in the same order in the
 828 generated chain. */
 829
 830 if (yield == FF_DELIVERED || yield == FF_NOTDELIVERED ||
 831     yield == FF_FAIL || yield == FF_FREEZE)
 832   {
 833   address_item **nextp = generated;
 834
 835   for (;;)
 836     {
 837     int i, reply_options;
 838     address_item *addr;
 839     uschar *recipient;
 840     uschar *expandn[EXPAND_MAXN + 2];
 841
 842     /* First string is the address; NULL => end of addresses */
 843
 844     if (!rda_read_string(fd, &recipient)) goto DISASTER;
 845     if (recipient == NULL) break;
 846
 847     /* Hang on the end of the chain */
 848
 849     addr = deliver_make_addr(recipient, FALSE);
 850     *nextp = addr;
 851     nextp = &(addr->next);
 852
 853     /* Next comes the mode and the flags fields */
 854
 855     if (read(fd, &(addr->mode), sizeof(addr->mode)) != sizeof(addr->mode) ||
 856         read(fd, &(addr->flags), sizeof(addr->flags)) != sizeof(addr->flags) ||
 857         !rda_read_string(fd, &(addr->p.errors_address))) goto DISASTER;
 858
 859     /* Next comes a possible setting for $thisaddress and any numerical
 860     variables for pipe expansion, terminated by a NULL string. The maximum
 861     number of numericals is EXPAND_MAXN. Note that we put filter_thisaddress
 862     into the zeroth item in the vector - this is sorted out inside the pipe
 863     transport. */
 864
 865     for (i = 0; i < EXPAND_MAXN + 1; i++)
 866       {
 867       uschar *temp;
 868       if (!rda_read_string(fd, &temp)) goto DISASTER;
 869       if (i == 0) filter_thisaddress = temp;           /* Just in case */
 870       expandn[i] = temp;
 871       if (temp == NULL) break;
 872       }
 873
 874     if (i > 0)
 875       {
 876       addr->pipe_expandn = store_get((i+1) * sizeof(uschar **));
 877       addr->pipe_expandn[i] = NULL;
 878       while (--i >= 0) addr->pipe_expandn[i] = expandn[i];
 879       }
 880
 881     /* Then an int containing reply options; zero => no reply data. */
 882
 883     if (read(fd, &reply_options, sizeof(int)) != sizeof(int)) goto DISASTER;
 884     if ((reply_options & REPLY_EXISTS) != 0)
 885       {
 886       addr->reply = store_get(sizeof(reply_item));
 887
 888       addr->reply->file_expand = (reply_options & REPLY_EXPAND) != 0;
 889       addr->reply->return_message = (reply_options & REPLY_RETURN) != 0;
 890
 891       if (read(fd,&(addr->reply->expand_forbid),sizeof(int)) !=
 892             sizeof(int) ||
 893           read(fd,&(addr->reply->once_repeat),sizeof(time_t)) !=
 894             sizeof(time_t) ||
 895           !rda_read_string(fd, &(addr->reply->to)) ||
 896           !rda_read_string(fd, &(addr->reply->cc)) ||
 897           !rda_read_string(fd, &(addr->reply->bcc)) ||
 898           !rda_read_string(fd, &(addr->reply->from)) ||
 899           !rda_read_string(fd, &(addr->reply->reply_to)) ||
 900           !rda_read_string(fd, &(addr->reply->subject)) ||
 901           !rda_read_string(fd, &(addr->reply->headers)) ||
 902           !rda_read_string(fd, &(addr->reply->text)) ||
 903           !rda_read_string(fd, &(addr->reply->file)) ||
 904           !rda_read_string(fd, &(addr->reply->logfile)) ||
 905           !rda_read_string(fd, &(addr->reply->oncelog)))
 906         goto DISASTER;
 907       }
 908     }
 909   }
 910
 911 /* All data has been transferred from the sub-process. Reap it, close the
 912 reading end of the pipe, and we are done. */
 913
 914 WAIT_EXIT:
 915 while ((rc = wait(&status)) != pid)
 916   {
 917   if (rc < 0 && errno == ECHILD)      /* Process has vanished */
 918     {
 919     log_write(0, LOG_MAIN, "redirection process %d vanished unexpectedly", pid);
 920     goto FINAL_EXIT;
 921     }
 922   }
 923
 924 if (had_disaster)
 925   {
 926   *error = string_sprintf("internal problem in %s: failure to transfer "
 927     "data from subprocess: status=%04x%s%s%s", rname,
 928     status, readerror,
 929     (*error == NULL)? US"" : US": error=",
 930     (*error == NULL)? US"" : *error);
 931   log_write(0, LOG_MAIN|LOG_PANIC, "%s", *error);
 932   }
 933 else if (status != 0)
 934   {
 935   log_write(0, LOG_MAIN|LOG_PANIC, "internal problem in %s: unexpected status "
 936     "%04x from redirect subprocess (but data correctly received)", rname,
 937     status);
 938   }
 939
 940 FINAL_EXIT:
 941 close(fd);
 942 signal(SIGCHLD, oldsignal);   /* restore */
 943 return yield;
 944
 945
 946 /* Come here if the data indicates removal of a header that we can't find */
 947
 948 DISASTER_NO_HEADER:
 949 readerror = US" readerror=bad header identifier";
 950 had_disaster = TRUE;
 951 yield = FF_ERROR;
 952 goto WAIT_EXIT;
 953
 954 /* Come here is there's a shambles in transferring the data over the pipe. The
 955 value of errno should still be set. */
 956
 957 DISASTER:
 958 readerror = string_sprintf(" readerror='%s'", strerror(errno));
 959 had_disaster = TRUE;
 960 yield = FF_ERROR;
 961 goto WAIT_EXIT;
 962 }
 963
 964 /* End of rda.c */