5b7fa1f5cd0b52c9ab04a9abed3ae42f89dc2a6c
[exim.git] / src / src / transports / pipe.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2017 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8
9 #include "../exim.h"
10 #include "pipe.h"
11
12 #ifdef HAVE_SETCLASSRESOURCES
13 #include <login_cap.h>
14 #endif
15
16
17
18 /* Options specific to the pipe transport. They must be in alphabetic
19 order (note that "_" comes before the lower case letters). Those starting
20 with "*" are not settable by the user but are used by the option-reading
21 software for alternative value types. Some options are stored in the transport
22 instance block so as to be publicly visible; these are flagged with opt_public.
23 */
24
25 optionlist pipe_transport_options[] = {
26 { "allow_commands", opt_stringptr,
27 (void *)offsetof(pipe_transport_options_block, allow_commands) },
28 { "batch_id", opt_stringptr | opt_public,
29 (void *)offsetof(transport_instance, batch_id) },
30 { "batch_max", opt_int | opt_public,
31 (void *)offsetof(transport_instance, batch_max) },
32 { "check_string", opt_stringptr,
33 (void *)offsetof(pipe_transport_options_block, check_string) },
34 { "command", opt_stringptr,
35 (void *)offsetof(pipe_transport_options_block, cmd) },
36 { "environment", opt_stringptr,
37 (void *)offsetof(pipe_transport_options_block, environment) },
38 { "escape_string", opt_stringptr,
39 (void *)offsetof(pipe_transport_options_block, escape_string) },
40 { "force_command", opt_bool,
41 (void *)offsetof(pipe_transport_options_block, force_command) },
42 { "freeze_exec_fail", opt_bool,
43 (void *)offsetof(pipe_transport_options_block, freeze_exec_fail) },
44 { "freeze_signal", opt_bool,
45 (void *)offsetof(pipe_transport_options_block, freeze_signal) },
46 { "ignore_status", opt_bool,
47 (void *)offsetof(pipe_transport_options_block, ignore_status) },
48 { "log_defer_output", opt_bool | opt_public,
49 (void *)offsetof(transport_instance, log_defer_output) },
50 { "log_fail_output", opt_bool | opt_public,
51 (void *)offsetof(transport_instance, log_fail_output) },
52 { "log_output", opt_bool | opt_public,
53 (void *)offsetof(transport_instance, log_output) },
54 { "max_output", opt_mkint,
55 (void *)offsetof(pipe_transport_options_block, max_output) },
56 { "message_prefix", opt_stringptr,
57 (void *)offsetof(pipe_transport_options_block, message_prefix) },
58 { "message_suffix", opt_stringptr,
59 (void *)offsetof(pipe_transport_options_block, message_suffix) },
60 { "path", opt_stringptr,
61 (void *)offsetof(pipe_transport_options_block, path) },
62 { "permit_coredump", opt_bool,
63 (void *)offsetof(pipe_transport_options_block, permit_coredump) },
64 { "pipe_as_creator", opt_bool | opt_public,
65 (void *)offsetof(transport_instance, deliver_as_creator) },
66 { "restrict_to_path", opt_bool,
67 (void *)offsetof(pipe_transport_options_block, restrict_to_path) },
68 { "return_fail_output",opt_bool | opt_public,
69 (void *)offsetof(transport_instance, return_fail_output) },
70 { "return_output", opt_bool | opt_public,
71 (void *)offsetof(transport_instance, return_output) },
72 { "temp_errors", opt_stringptr,
73 (void *)offsetof(pipe_transport_options_block, temp_errors) },
74 { "timeout", opt_time,
75 (void *)offsetof(pipe_transport_options_block, timeout) },
76 { "timeout_defer", opt_bool,
77 (void *)offsetof(pipe_transport_options_block, timeout_defer) },
78 { "umask", opt_octint,
79 (void *)offsetof(pipe_transport_options_block, umask) },
80 { "use_bsmtp", opt_bool,
81 (void *)offsetof(pipe_transport_options_block, use_bsmtp) },
82 #ifdef HAVE_SETCLASSRESOURCES
83 { "use_classresources", opt_bool,
84 (void *)offsetof(pipe_transport_options_block, use_classresources) },
85 #endif
86 { "use_crlf", opt_bool,
87 (void *)offsetof(pipe_transport_options_block, use_crlf) },
88 { "use_shell", opt_bool,
89 (void *)offsetof(pipe_transport_options_block, use_shell) },
90 };
91
92 /* Size of the options list. An extern variable has to be used so that its
93 address can appear in the tables drtables.c. */
94
95 int pipe_transport_options_count =
96 sizeof(pipe_transport_options)/sizeof(optionlist);
97
98
99 #ifdef MACRO_PREDEF
100
101 /* Dummy values */
102 pipe_transport_options_block pipe_transport_option_defaults = {0};
103 void pipe_transport_init(transport_instance *tblock) {}
104 BOOL pipe_transport_entry(transport_instance *tblock, address_item *addr) {return FALSE;}
105
106 #else /*!MACRO_PREDEF*/
107
108
109 /* Default private options block for the pipe transport. */
110
111 pipe_transport_options_block pipe_transport_option_defaults = {
112 NULL, /* cmd */
113 NULL, /* allow_commands */
114 NULL, /* environment */
115 US"/bin:/usr/bin", /* path */
116 NULL, /* message_prefix (reset in init if not bsmtp) */
117 NULL, /* message_suffix (ditto) */
118 US mac_expanded_string(EX_TEMPFAIL) ":" /* temp_errors */
119 mac_expanded_string(EX_CANTCREAT),
120 NULL, /* check_string */
121 NULL, /* escape_string */
122 022, /* umask */
123 20480, /* max_output */
124 60*60, /* timeout */
125 0, /* options */
126 FALSE, /* force_command */
127 FALSE, /* freeze_exec_fail */
128 FALSE, /* freeze_signal */
129 FALSE, /* ignore_status */
130 FALSE, /* permit_coredump */
131 FALSE, /* restrict_to_path */
132 FALSE, /* timeout_defer */
133 FALSE, /* use_shell */
134 FALSE, /* use_bsmtp */
135 FALSE, /* use_classresources */
136 FALSE /* use_crlf */
137 };
138
139
140
141 /*************************************************
142 * Setup entry point *
143 *************************************************/
144
145 /* Called for each delivery in the privileged state, just before the uid/gid
146 are changed and the main entry point is called. In a system that supports the
147 login_cap facilities, this function is used to set the class resource limits
148 for the user. It may also re-enable coredumps.
149
150 Arguments:
151 tblock points to the transport instance
152 addrlist addresses about to be delivered (not used)
153 dummy not used (doesn't pass back data)
154 uid the uid that will be set (not used)
155 gid the gid that will be set (not used)
156 errmsg where to put an error message
157
158 Returns: OK, FAIL, or DEFER
159 */
160
161 static int
162 pipe_transport_setup(transport_instance *tblock, address_item *addrlist,
163 transport_feedback *dummy, uid_t uid, gid_t gid, uschar **errmsg)
164 {
165 pipe_transport_options_block *ob =
166 (pipe_transport_options_block *)(tblock->options_block);
167
168 addrlist = addrlist; /* Keep compiler happy */
169 dummy = dummy;
170 uid = uid;
171 gid = gid;
172 errmsg = errmsg;
173 ob = ob;
174
175 #ifdef HAVE_SETCLASSRESOURCES
176 if (ob->use_classresources)
177 {
178 struct passwd *pw = getpwuid(uid);
179 if (pw != NULL)
180 {
181 login_cap_t *lc = login_getpwclass(pw);
182 if (lc != NULL)
183 {
184 setclassresources(lc);
185 login_close(lc);
186 }
187 }
188 }
189 #endif
190
191 #ifdef RLIMIT_CORE
192 if (ob->permit_coredump)
193 {
194 struct rlimit rl;
195 rl.rlim_cur = RLIM_INFINITY;
196 rl.rlim_max = RLIM_INFINITY;
197 if (setrlimit(RLIMIT_CORE, &rl) < 0)
198 {
199 #ifdef SETRLIMIT_NOT_SUPPORTED
200 if (errno != ENOSYS && errno != ENOTSUP)
201 #endif
202 log_write(0, LOG_MAIN,
203 "delivery setrlimit(RLIMIT_CORE, RLIM_INFINITY) failed: %s",
204 strerror(errno));
205 }
206 }
207 #endif
208
209 return OK;
210 }
211
212
213
214 /*************************************************
215 * Initialization entry point *
216 *************************************************/
217
218 /* Called for each instance, after its options have been read, to
219 enable consistency checks to be done, or anything else that needs
220 to be set up. */
221
222 void
223 pipe_transport_init(transport_instance *tblock)
224 {
225 pipe_transport_options_block *ob =
226 (pipe_transport_options_block *)(tblock->options_block);
227
228 /* Set up the setup entry point, to be called in the privileged state */
229
230 tblock->setup = pipe_transport_setup;
231
232 /* If pipe_as_creator is set, then uid/gid should not be set. */
233
234 if (tblock->deliver_as_creator && (tblock->uid_set || tblock->gid_set ||
235 tblock->expand_uid != NULL || tblock->expand_gid != NULL))
236 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
237 "both pipe_as_creator and an explicit uid/gid are set for the %s "
238 "transport", tblock->name);
239
240 /* If a fixed uid field is set, then a gid field must also be set. */
241
242 if (tblock->uid_set && !tblock->gid_set && tblock->expand_gid == NULL)
243 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
244 "user set without group for the %s transport", tblock->name);
245
246 /* Temp_errors must consist only of digits and colons, but there can be
247 spaces round the colons, so allow them too. */
248
249 if (ob->temp_errors != NULL && Ustrcmp(ob->temp_errors, "*") != 0)
250 {
251 size_t p = Ustrspn(ob->temp_errors, "0123456789: ");
252 if (ob->temp_errors[p] != 0)
253 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
254 "temp_errors must be a list of numbers or an asterisk for the %s "
255 "transport", tblock->name);
256 }
257
258 /* Only one of return_output/return_fail_output or log_output/log_fail_output
259 should be set. */
260
261 if (tblock->return_output && tblock->return_fail_output)
262 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
263 "both return_output and return_fail_output set for %s transport",
264 tblock->name);
265
266 if (tblock->log_output && tblock->log_fail_output)
267 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
268 "both log_output and log_fail_output set for the %s transport",
269 tblock->name);
270
271 /* If batch SMTP is set, force the check and escape strings, and arrange that
272 headers are also escaped. */
273
274 if (ob->use_bsmtp)
275 {
276 ob->check_string = US".";
277 ob->escape_string = US"..";
278 ob->options |= topt_escape_headers;
279 }
280
281 /* If not batch SMTP, and message_prefix or message_suffix are unset, insert
282 default values for them. */
283
284 else
285 {
286 if (ob->message_prefix == NULL) ob->message_prefix =
287 US"From ${if def:return_path{$return_path}{MAILER-DAEMON}} ${tod_bsdinbox}\n";
288 if (ob->message_suffix == NULL) ob->message_suffix = US"\n";
289 }
290
291 /* The restrict_to_path and use_shell options are incompatible */
292
293 if (ob->restrict_to_path && ob->use_shell)
294 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
295 "both restrict_to_path and use_shell set for %s transport",
296 tblock->name);
297
298 /* The allow_commands and use_shell options are incompatible */
299
300 if (ob->allow_commands && ob->use_shell)
301 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
302 "both allow_commands and use_shell set for %s transport",
303 tblock->name);
304
305 /* Set up the bitwise options for transport_write_message from the various
306 driver options. Only one of body_only and headers_only can be set. */
307
308 ob->options |=
309 (tblock->body_only? topt_no_headers : 0) |
310 (tblock->headers_only? topt_no_body : 0) |
311 (tblock->return_path_add? topt_add_return_path : 0) |
312 (tblock->delivery_date_add? topt_add_delivery_date : 0) |
313 (tblock->envelope_to_add? topt_add_envelope_to : 0) |
314 (ob->use_crlf? topt_use_crlf : 0);
315 }
316
317
318
319 /*************************************************
320 * Set up direct (non-shell) command *
321 *************************************************/
322
323 /* This function is called when a command line is to be parsed by the transport
324 and executed directly, without the use of /bin/sh.
325
326 Arguments:
327 argvptr pointer to anchor for argv vector
328 cmd points to the command string
329 expand_arguments true if expansion is to occur
330 expand_fail error if expansion fails
331 addr chain of addresses
332 tname the transport name
333 ob the transport options block
334
335 Returns: TRUE if all went well; otherwise an error will be
336 set in the first address and FALSE returned
337 */
338
339 static BOOL
340 set_up_direct_command(const uschar ***argvptr, uschar *cmd,
341 BOOL expand_arguments, int expand_fail, address_item *addr, uschar *tname,
342 pipe_transport_options_block *ob)
343 {
344 BOOL permitted = FALSE;
345 const uschar **argv;
346
347 /* Set up "transport <name>" to be put in any error messages, and then
348 call the common function for creating an argument list and expanding
349 the items if necessary. If it fails, this function fails (error information
350 is in the addresses). */
351
352 if (!transport_set_up_command(argvptr, cmd, expand_arguments, expand_fail,
353 addr, string_sprintf("%.50s transport", tname), NULL))
354 return FALSE;
355
356 /* Point to the set-up arguments. */
357
358 argv = *argvptr;
359
360 /* If allow_commands is set, see if the command is in the permitted list. */
361
362 if (ob->allow_commands)
363 {
364 int sep = 0;
365 const uschar *s;
366 uschar *p;
367
368 if (!(s = expand_string(ob->allow_commands)))
369 {
370 addr->transport_return = DEFER;
371 addr->message = string_sprintf("failed to expand string \"%s\" "
372 "for %s transport: %s", ob->allow_commands, tname, expand_string_message);
373 return FALSE;
374 }
375
376 while ((p = string_nextinlist(&s, &sep, NULL, 0)))
377 if (Ustrcmp(p, argv[0]) == 0) { permitted = TRUE; break; }
378 }
379
380 /* If permitted is TRUE it means the command was found in the allowed list, and
381 no further checks are done. If permitted = FALSE, it either means
382 allow_commands wasn't set, or that the command didn't match anything in the
383 list. In both cases, if restrict_to_path is set, we fail if the command
384 contains any slashes, but if restrict_to_path is not set, we must fail the
385 command only if allow_commands is set. */
386
387 if (!permitted)
388 {
389 if (ob->restrict_to_path)
390 {
391 if (Ustrchr(argv[0], '/') != NULL)
392 {
393 addr->transport_return = FAIL;
394 addr->message = string_sprintf("\"/\" found in \"%s\" (command for %s "
395 "transport) - failed for security reasons", cmd, tname);
396 return FALSE;
397 }
398 }
399
400 else if (ob->allow_commands)
401 {
402 addr->transport_return = FAIL;
403 addr->message = string_sprintf("\"%s\" command not permitted by %s "
404 "transport", argv[0], tname);
405 return FALSE;
406 }
407 }
408
409 /* If the command is not an absolute path, search the PATH directories
410 for it. */
411
412 if (argv[0][0] != '/')
413 {
414 int sep = 0;
415 uschar *p;
416 const uschar *listptr = expand_string(ob->path);
417
418 while ((p = string_nextinlist(&listptr, &sep, NULL, 0)))
419 {
420 struct stat statbuf;
421 sprintf(CS big_buffer, "%.256s/%.256s", p, argv[0]);
422 if (Ustat(big_buffer, &statbuf) == 0)
423 {
424 argv[0] = string_copy(big_buffer);
425 break;
426 }
427 }
428 if (!p)
429 {
430 addr->transport_return = FAIL;
431 addr->message = string_sprintf("\"%s\" command not found for %s transport",
432 argv[0], tname);
433 return FALSE;
434 }
435 }
436
437 return TRUE;
438 }
439
440
441 /*************************************************
442 * Set up shell command *
443 *************************************************/
444
445 /* This function is called when a command line is to be passed to /bin/sh
446 without parsing inside the transport.
447
448 Arguments:
449 argvptr pointer to anchor for argv vector
450 cmd points to the command string
451 expand_arguments true if expansion is to occur
452 expand_fail error if expansion fails
453 addr chain of addresses
454 tname the transport name
455
456 Returns: TRUE if all went well; otherwise an error will be
457 set in the first address and FALSE returned
458 */
459
460 static BOOL
461 set_up_shell_command(const uschar ***argvptr, uschar *cmd,
462 BOOL expand_arguments, int expand_fail, address_item *addr, uschar *tname)
463 {
464 const uschar **argv;
465
466 *argvptr = argv = store_get((4)*sizeof(uschar *));
467
468 argv[0] = US"/bin/sh";
469 argv[1] = US"-c";
470
471 /* We have to take special action to handle the special "variable" called
472 $pipe_addresses, which is not recognized by the normal expansion function. */
473
474 if (expand_arguments)
475 {
476 uschar *s = cmd;
477 uschar *p = Ustrstr(cmd, "pipe_addresses");
478 gstring * g = NULL;
479
480 DEBUG(D_transport)
481 debug_printf("shell pipe command before expansion:\n %s\n", cmd);
482
483 /* Allow $recipients in the expansion iff it comes from a system filter */
484
485 enable_dollar_recipients = addr && addr->parent &&
486 Ustrcmp(addr->parent->address, "system-filter") == 0;
487
488 if (p != NULL && (
489 (p > cmd && p[-1] == '$') ||
490 (p > cmd + 1 && p[-2] == '$' && p[-1] == '{' && p[14] == '}')))
491 {
492 address_item *ad;
493 uschar *q = p + 14;
494
495 if (p[-1] == '{') { q++; p--; }
496
497 g = string_get(Ustrlen(cmd) + 64);
498 g = string_catn(g, cmd, p - cmd - 1);
499
500 for (ad = addr; ad; ad = ad->next)
501 {
502 /*XXX string_append_listele() ? */
503 if (ad != addr) g = string_catn(g, US" ", 1);
504 g = string_cat(g, ad->address);
505 }
506
507 g = string_cat(g, q);
508 argv[2] = (cmd = string_from_gstring(g)) ? expand_string(cmd) : NULL;
509 }
510 else
511 argv[2] = expand_string(cmd);
512
513 enable_dollar_recipients = FALSE;
514
515 if (!argv[2])
516 {
517 addr->transport_return = search_find_defer ? DEFER : expand_fail;
518 addr->message = string_sprintf("Expansion of command \"%s\" "
519 "in %s transport failed: %s",
520 cmd, tname, expand_string_message);
521 return FALSE;
522 }
523
524 DEBUG(D_transport)
525 debug_printf("shell pipe command after expansion:\n %s\n", argv[2]);
526 }
527 else
528 {
529 DEBUG(D_transport)
530 debug_printf("shell pipe command (no expansion):\n %s\n", cmd);
531 argv[2] = cmd;
532 }
533
534 argv[3] = US 0;
535 return TRUE;
536 }
537
538
539
540
541 /*************************************************
542 * Main entry point *
543 *************************************************/
544
545 /* See local README for interface details. This transport always returns FALSE,
546 indicating that the status in the first address is the status for all addresses
547 in a batch. */
548
549 BOOL
550 pipe_transport_entry(
551 transport_instance *tblock, /* data for this instantiation */
552 address_item *addr) /* address(es) we are working on */
553 {
554 pid_t pid, outpid;
555 int fd_in, fd_out, rc;
556 int envcount = 0;
557 int envsep = 0;
558 int expand_fail;
559 pipe_transport_options_block *ob =
560 (pipe_transport_options_block *)(tblock->options_block);
561 int timeout = ob->timeout;
562 BOOL written_ok = FALSE;
563 BOOL expand_arguments;
564 const uschar **argv;
565 uschar *envp[50];
566 const uschar *envlist = ob->environment;
567 uschar *cmd, *ss;
568 uschar *eol = ob->use_crlf ? US"\r\n" : US"\n";
569 transport_ctx tctx = {
570 {0},
571 tblock,
572 addr,
573 ob->check_string,
574 ob->escape_string,
575 ob->options /* set at initialization time */
576 };
577
578 DEBUG(D_transport) debug_printf("%s transport entered\n", tblock->name);
579
580 /* Set up for the good case */
581
582 addr->transport_return = OK;
583 addr->basic_errno = 0;
584
585 /* Pipes are not accepted as general addresses, but they can be generated from
586 .forward files or alias files. In those cases, the pfr flag is set, and the
587 command to be obeyed is pointed to by addr->local_part; it starts with the pipe
588 symbol. In other cases, the command is supplied as one of the pipe transport's
589 options. */
590
591 if (testflag(addr, af_pfr) && addr->local_part[0] == '|')
592 {
593 if (ob->force_command)
594 {
595 /* Enables expansion of $address_pipe into separate arguments */
596 setflag(addr, af_force_command);
597 cmd = ob->cmd;
598 expand_arguments = TRUE;
599 expand_fail = PANIC;
600 }
601 else
602 {
603 cmd = addr->local_part + 1;
604 while (isspace(*cmd)) cmd++;
605 expand_arguments = testflag(addr, af_expand_pipe);
606 expand_fail = FAIL;
607 }
608 }
609 else
610 {
611 cmd = ob->cmd;
612 expand_arguments = TRUE;
613 expand_fail = PANIC;
614 }
615
616 /* If no command has been supplied, we are in trouble.
617 * We also check for an empty string since it may be
618 * coming from addr->local_part[0] == '|'
619 */
620
621 if (cmd == NULL || *cmd == '\0')
622 {
623 addr->transport_return = DEFER;
624 addr->message = string_sprintf("no command specified for %s transport",
625 tblock->name);
626 return FALSE;
627 }
628
629 /* When a pipe is set up by a filter file, there may be values for $thisaddress
630 and numerical the variables in existence. These are passed in
631 addr->pipe_expandn for use here. */
632
633 if (expand_arguments && addr->pipe_expandn)
634 {
635 uschar **ss = addr->pipe_expandn;
636 expand_nmax = -1;
637 if (*ss != NULL) filter_thisaddress = *ss++;
638 while (*ss != NULL)
639 {
640 expand_nstring[++expand_nmax] = *ss;
641 expand_nlength[expand_nmax] = Ustrlen(*ss++);
642 }
643 }
644
645 /* The default way of processing the command is to split it up into arguments
646 here, and run it directly. This offers some security advantages. However, there
647 are installations that want by default to run commands under /bin/sh always, so
648 there is an option to do that. */
649
650 if (ob->use_shell)
651 {
652 if (!set_up_shell_command(&argv, cmd, expand_arguments, expand_fail, addr,
653 tblock->name)) return FALSE;
654 }
655 else if (!set_up_direct_command(&argv, cmd, expand_arguments, expand_fail, addr,
656 tblock->name, ob)) return FALSE;
657
658 expand_nmax = -1; /* Reset */
659 filter_thisaddress = NULL;
660
661 /* Set up the environment for the command. */
662
663 envp[envcount++] = string_sprintf("LOCAL_PART=%s", deliver_localpart);
664 envp[envcount++] = string_sprintf("LOGNAME=%s", deliver_localpart);
665 envp[envcount++] = string_sprintf("USER=%s", deliver_localpart);
666 envp[envcount++] = string_sprintf("LOCAL_PART_PREFIX=%#s",
667 deliver_localpart_prefix);
668 envp[envcount++] = string_sprintf("LOCAL_PART_SUFFIX=%#s",
669 deliver_localpart_suffix);
670 envp[envcount++] = string_sprintf("DOMAIN=%s", deliver_domain);
671 envp[envcount++] = string_sprintf("HOME=%#s", deliver_home);
672 envp[envcount++] = string_sprintf("MESSAGE_ID=%s", message_id);
673 envp[envcount++] = string_sprintf("PATH=%s", expand_string(ob->path));
674 envp[envcount++] = string_sprintf("RECIPIENT=%#s%#s%#s@%#s",
675 deliver_localpart_prefix, deliver_localpart, deliver_localpart_suffix,
676 deliver_domain);
677 envp[envcount++] = string_sprintf("QUALIFY_DOMAIN=%s", qualify_domain_sender);
678 envp[envcount++] = string_sprintf("SENDER=%s", sender_address);
679 envp[envcount++] = US"SHELL=/bin/sh";
680
681 if (addr->host_list != NULL)
682 envp[envcount++] = string_sprintf("HOST=%s", addr->host_list->name);
683
684 if (timestamps_utc) envp[envcount++] = US"TZ=UTC";
685 else if (timezone_string != NULL && timezone_string[0] != 0)
686 envp[envcount++] = string_sprintf("TZ=%s", timezone_string);
687
688 /* Add any requested items */
689
690 if (envlist)
691 {
692 envlist = expand_cstring(envlist);
693 if (envlist == NULL)
694 {
695 addr->transport_return = DEFER;
696 addr->message = string_sprintf("failed to expand string \"%s\" "
697 "for %s transport: %s", ob->environment, tblock->name,
698 expand_string_message);
699 return FALSE;
700 }
701 }
702
703 while ((ss = string_nextinlist(&envlist, &envsep, big_buffer, big_buffer_size)))
704 {
705 if (envcount > nelem(envp) - 2)
706 {
707 addr->transport_return = DEFER;
708 addr->message = string_sprintf("too many environment settings for "
709 "%s transport", tblock->name);
710 return FALSE;
711 }
712 envp[envcount++] = string_copy(ss);
713 }
714
715 envp[envcount] = NULL;
716
717 /* If the -N option is set, can't do any more. */
718
719 if (dont_deliver)
720 {
721 DEBUG(D_transport)
722 debug_printf("*** delivery by %s transport bypassed by -N option",
723 tblock->name);
724 return FALSE;
725 }
726
727
728 /* Handling the output from the pipe is tricky. If a file for catching this
729 output is provided, we could in theory just hand that fd over to the process,
730 but this isn't very safe because it might loop and carry on writing for
731 ever (which is exactly what happened in early versions of Exim). Therefore we
732 use the standard child_open() function, which creates pipes. We can then read
733 our end of the output pipe and count the number of bytes that come through,
734 chopping the sub-process if it exceeds some limit.
735
736 However, this means we want to run a sub-process with both its input and output
737 attached to pipes. We can't handle that easily from a single parent process
738 using straightforward code such as the transport_write_message() function
739 because the subprocess might not be reading its input because it is trying to
740 write to a full output pipe. The complication of redesigning the world to
741 handle this is too great - simpler just to run another process to do the
742 reading of the output pipe. */
743
744
745 /* As this is a local transport, we are already running with the required
746 uid/gid and current directory. Request that the new process be a process group
747 leader, so we can kill it and all its children on a timeout. */
748
749 if ((pid = child_open(USS argv, envp, ob->umask, &fd_in, &fd_out, TRUE)) < 0)
750 {
751 addr->transport_return = DEFER;
752 addr->message = string_sprintf(
753 "Failed to create child process for %s transport: %s", tblock->name,
754 strerror(errno));
755 return FALSE;
756 }
757 tctx.u.fd = fd_in;
758
759 /* Now fork a process to handle the output that comes down the pipe. */
760
761 if ((outpid = fork()) < 0)
762 {
763 addr->basic_errno = errno;
764 addr->transport_return = DEFER;
765 addr->message = string_sprintf(
766 "Failed to create process for handling output in %s transport",
767 tblock->name);
768 (void)close(fd_in);
769 (void)close(fd_out);
770 return FALSE;
771 }
772
773 /* This is the code for the output-handling subprocess. Read from the pipe
774 in chunks, and write to the return file if one is provided. Keep track of
775 the number of bytes handled. If the limit is exceeded, try to kill the
776 subprocess group, and in any case close the pipe and exit, which should cause
777 the subprocess to fail. */
778
779 if (outpid == 0)
780 {
781 int count = 0;
782 (void)close(fd_in);
783 set_process_info("reading output from |%s", cmd);
784 while ((rc = read(fd_out, big_buffer, big_buffer_size)) > 0)
785 {
786 if (addr->return_file >= 0)
787 if(write(addr->return_file, big_buffer, rc) != rc)
788 DEBUG(D_transport) debug_printf("Problem writing to return_file\n");
789 count += rc;
790 if (count > ob->max_output)
791 {
792 DEBUG(D_transport) debug_printf("Too much output from pipe - killed\n");
793 if (addr->return_file >= 0)
794 {
795 uschar *message = US"\n\n*** Too much output - remainder discarded ***\n";
796 rc = Ustrlen(message);
797 if(write(addr->return_file, message, rc) != rc)
798 DEBUG(D_transport) debug_printf("Problem writing to return_file\n");
799 }
800 killpg(pid, SIGKILL);
801 break;
802 }
803 }
804 (void)close(fd_out);
805 _exit(0);
806 }
807
808 (void)close(fd_out); /* Not used in this process */
809
810
811 /* Carrying on now with the main parent process. Attempt to write the message
812 to it down the pipe. It is a fallacy to think that you can detect write errors
813 when the sub-process fails to read the pipe. The parent process may complete
814 writing and close the pipe before the sub-process completes. We could sleep a
815 bit here to let the sub-process get going, but it may still not complete. So we
816 ignore all writing errors. (When in the test harness, we do do a short sleep so
817 any debugging output is likely to be in the same order.) */
818
819 if (running_in_test_harness) millisleep(500);
820
821 DEBUG(D_transport) debug_printf("Writing message to pipe\n");
822
823 /* Arrange to time out writes if there is a timeout set. */
824
825 if (timeout > 0)
826 {
827 sigalrm_seen = FALSE;
828 transport_write_timeout = timeout;
829 }
830
831 /* Reset the counter of bytes written */
832
833 transport_count = 0;
834
835 /* First write any configured prefix information */
836
837 if (ob->message_prefix != NULL)
838 {
839 uschar *prefix = expand_string(ob->message_prefix);
840 if (prefix == NULL)
841 {
842 addr->transport_return = search_find_defer? DEFER : PANIC;
843 addr->message = string_sprintf("Expansion of \"%s\" (prefix for %s "
844 "transport) failed: %s", ob->message_prefix, tblock->name,
845 expand_string_message);
846 return FALSE;
847 }
848 if (!transport_write_block(&tctx, prefix, Ustrlen(prefix), FALSE))
849 goto END_WRITE;
850 }
851
852 /* If the use_bsmtp option is set, we need to write SMTP prefix information.
853 The various different values for batching are handled outside; if there is more
854 than one address available here, all must be included. Force SMTP dot-handling.
855 */
856
857 if (ob->use_bsmtp)
858 {
859 address_item *a;
860
861 if (!transport_write_string(fd_in, "MAIL FROM:<%s>%s", return_path, eol))
862 goto END_WRITE;
863
864 for (a = addr; a; a = a->next)
865 if (!transport_write_string(fd_in,
866 "RCPT TO:<%s>%s",
867 transport_rcpt_address(a, tblock->rcpt_include_affixes),
868 eol))
869 goto END_WRITE;
870
871 if (!transport_write_string(fd_in, "DATA%s", eol)) goto END_WRITE;
872 }
873
874 /* Now the actual message */
875
876 if (!transport_write_message(&tctx, 0))
877 goto END_WRITE;
878
879 /* Now any configured suffix */
880
881 if (ob->message_suffix)
882 {
883 uschar *suffix = expand_string(ob->message_suffix);
884 if (!suffix)
885 {
886 addr->transport_return = search_find_defer? DEFER : PANIC;
887 addr->message = string_sprintf("Expansion of \"%s\" (suffix for %s "
888 "transport) failed: %s", ob->message_suffix, tblock->name,
889 expand_string_message);
890 return FALSE;
891 }
892 if (!transport_write_block(&tctx, suffix, Ustrlen(suffix), FALSE))
893 goto END_WRITE;
894 }
895
896 /* If local_smtp, write the terminating dot. */
897
898 if (ob->use_bsmtp && !transport_write_string(fd_in, ".%s", eol))
899 goto END_WRITE;
900
901 /* Flag all writing completed successfully. */
902
903 written_ok = TRUE;
904
905 /* Come here if there are errors during writing. */
906
907 END_WRITE:
908
909 /* OK, the writing is now all done. Close the pipe. */
910
911 (void) close(fd_in);
912
913 /* Handle errors during writing. For timeouts, set the timeout for waiting for
914 the child process to 1 second. If the process at the far end of the pipe died
915 without reading all of it, we expect an EPIPE error, which should be ignored.
916 We used also to ignore WRITEINCOMPLETE but the writing function is now cleverer
917 at handling OS where the death of a pipe doesn't give EPIPE immediately. See
918 comments therein. */
919
920 if (!written_ok)
921 {
922 if (errno == ETIMEDOUT)
923 {
924 addr->message = string_sprintf("%stimeout while writing to pipe",
925 transport_filter_timed_out? "transport filter " : "");
926 addr->transport_return = ob->timeout_defer? DEFER : FAIL;
927 timeout = 1;
928 }
929 else if (errno == EPIPE)
930 {
931 debug_printf("transport error EPIPE ignored\n");
932 }
933 else
934 {
935 addr->transport_return = PANIC;
936 addr->basic_errno = errno;
937 if (errno == ERRNO_CHHEADER_FAIL)
938 addr->message =
939 string_sprintf("Failed to expand headers_add or headers_remove: %s",
940 expand_string_message);
941 else if (errno == ERRNO_FILTER_FAIL)
942 addr->message = string_sprintf("Transport filter process failed (%d)%s",
943 addr->more_errno,
944 (addr->more_errno == EX_EXECFAILED)? ": unable to execute command" : "");
945 else if (errno == ERRNO_WRITEINCOMPLETE)
946 addr->message = string_sprintf("Failed repeatedly to write data");
947 else
948 addr->message = string_sprintf("Error %d", errno);
949 return FALSE;
950 }
951 }
952
953 /* Wait for the child process to complete and take action if the returned
954 status is nonzero. The timeout will be just 1 second if any of the writes
955 above timed out. */
956
957 if ((rc = child_close(pid, timeout)) != 0)
958 {
959 uschar *tmsg = (addr->message == NULL)? US"" :
960 string_sprintf(" (preceded by %s)", addr->message);
961
962 /* The process did not complete in time; kill its process group and fail
963 the delivery. It appears to be necessary to kill the output process too, as
964 otherwise it hangs on for some time if the actual pipe process is sleeping.
965 (At least, that's what I observed on Solaris 2.5.1.) Since we are failing
966 the delivery, that shouldn't cause any problem. */
967
968 if (rc == -256)
969 {
970 killpg(pid, SIGKILL);
971 kill(outpid, SIGKILL);
972 addr->transport_return = ob->timeout_defer? DEFER : FAIL;
973 addr->message = string_sprintf("pipe delivery process timed out%s", tmsg);
974 }
975
976 /* Wait() failed. */
977
978 else if (rc == -257)
979 {
980 addr->transport_return = PANIC;
981 addr->message = string_sprintf("Wait() failed for child process of %s "
982 "transport: %s%s", tblock->name, strerror(errno), tmsg);
983 }
984
985 /* Since the transport_filter timed out we assume it has sent the child process
986 a malformed or incomplete data stream. Kill off the child process
987 and prevent checking its exit status as it will has probably exited in error.
988 This prevents the transport_filter timeout message from getting overwritten
989 by the exit error which is not the cause of the problem. */
990
991 else if (transport_filter_timed_out)
992 {
993 killpg(pid, SIGKILL);
994 kill(outpid, SIGKILL);
995 }
996
997 /* Either the process completed, but yielded a non-zero (necessarily
998 positive) status, or the process was terminated by a signal (rc will contain
999 the negation of the signal number). Treat killing by signal as failure unless
1000 status is being ignored. By default, the message is bounced back, unless
1001 freeze_signal is set, in which case it is frozen instead. */
1002
1003 else if (rc < 0)
1004 {
1005 if (ob->freeze_signal)
1006 {
1007 addr->transport_return = DEFER;
1008 addr->special_action = SPECIAL_FREEZE;
1009 addr->message = string_sprintf("Child process of %s transport (running "
1010 "command \"%s\") was terminated by signal %d (%s)%s", tblock->name, cmd,
1011 -rc, os_strsignal(-rc), tmsg);
1012 }
1013 else if (!ob->ignore_status)
1014 {
1015 addr->transport_return = FAIL;
1016 addr->message = string_sprintf("Child process of %s transport (running "
1017 "command \"%s\") was terminated by signal %d (%s)%s", tblock->name, cmd,
1018 -rc, os_strsignal(-rc), tmsg);
1019 }
1020 }
1021
1022 /* For positive values (process terminated with non-zero status), we need a
1023 status code to request deferral. A number of systems contain the following
1024 line in sysexits.h:
1025
1026 #define EX_TEMPFAIL 75
1027
1028 with the description
1029
1030 EX_TEMPFAIL -- temporary failure, indicating something that
1031 is not really an error. In sendmail, this means
1032 that a mailer (e.g.) could not create a connection,
1033 and the request should be reattempted later.
1034
1035 Based on this, we use exit code EX_TEMPFAIL as a default to mean "defer" when
1036 not ignoring the returned status. However, there is now an option that
1037 contains a list of temporary codes, with TEMPFAIL and CANTCREAT as defaults.
1038
1039 Another case that needs special treatment is if execve() failed (typically
1040 the command that was given is a non-existent path). By default this is
1041 treated as just another failure, but if freeze_exec_fail is set, the reaction
1042 is to freeze the message rather than bounce the address. Exim used to signal
1043 this failure with EX_UNAVAILABLE, which is defined in many systems as
1044
1045 #define EX_UNAVAILABLE 69
1046
1047 with the description
1048
1049 EX_UNAVAILABLE -- A service is unavailable. This can occur
1050 if a support program or file does not exist. This
1051 can also be used as a catchall message when something
1052 you wanted to do doesn't work, but you don't know why.
1053
1054 However, this can be confused with a command that actually returns 69 because
1055 something *it* wanted is unavailable. At release 4.21, Exim was changed to
1056 use return code 127 instead, because this is what the shell returns when it
1057 is unable to exec a command. We define it as EX_EXECFAILED, and use it in
1058 child.c to signal execve() failure and other unexpected failures such as
1059 setuid() not working - though that won't be the case here because we aren't
1060 changing uid. */
1061
1062 else
1063 {
1064 /* Always handle execve() failure specially if requested to */
1065
1066 if (ob->freeze_exec_fail && (rc == EX_EXECFAILED))
1067 {
1068 addr->transport_return = DEFER;
1069 addr->special_action = SPECIAL_FREEZE;
1070 addr->message = string_sprintf("pipe process failed to exec \"%s\"%s",
1071 cmd, tmsg);
1072 }
1073
1074 /* Otherwise take action only if not ignoring status */
1075
1076 else if (!ob->ignore_status)
1077 {
1078 uschar *ss;
1079 gstring * g;
1080 int i;
1081
1082 /* If temp_errors is "*" all codes are temporary. Initialization checks
1083 that it's either "*" or a list of numbers. If not "*", scan the list of
1084 temporary failure codes; if any match, the result is DEFER. */
1085
1086 if (ob->temp_errors[0] == '*')
1087 addr->transport_return = DEFER;
1088
1089 else
1090 {
1091 const uschar *s = ob->temp_errors;
1092 uschar *p;
1093 int sep = 0;
1094
1095 addr->transport_return = FAIL;
1096 while ((p = string_nextinlist(&s,&sep,NULL,0)))
1097 if (rc == Uatoi(p)) { addr->transport_return = DEFER; break; }
1098 }
1099
1100 /* Ensure the message contains the expanded command and arguments. This
1101 doesn't have to be brilliantly efficient - it is an error situation. */
1102
1103 addr->message = string_sprintf("Child process of %s transport returned "
1104 "%d", tblock->name, rc);
1105 g = string_cat(NULL, addr->message);
1106
1107 /* If the return code is > 128, it often means that a shell command
1108 was terminated by a signal. */
1109
1110 ss = (rc > 128)?
1111 string_sprintf("(could mean shell command ended by signal %d (%s))",
1112 rc-128, os_strsignal(rc-128)) :
1113 US os_strexit(rc);
1114
1115 if (*ss != 0)
1116 {
1117 g = string_catn(g, US" ", 1);
1118 g = string_cat (g, ss);
1119 }
1120
1121 /* Now add the command and arguments */
1122
1123 g = string_catn(g, US" from command:", 14);
1124
1125 for (i = 0; i < sizeof(argv)/sizeof(int *) && argv[i] != NULL; i++)
1126 {
1127 BOOL quote = FALSE;
1128 g = string_catn(g, US" ", 1);
1129 if (Ustrpbrk(argv[i], " \t") != NULL)
1130 {
1131 quote = TRUE;
1132 g = string_catn(g, US"\"", 1);
1133 }
1134 g = string_cat(g, argv[i]);
1135 if (quote)
1136 g = string_catn(g, US"\"", 1);
1137 }
1138
1139 /* Add previous filter timeout message, if present. */
1140
1141 if (*tmsg)
1142 g = string_cat(g, tmsg);
1143
1144 addr->message = string_from_gstring(g);
1145 }
1146 }
1147 }
1148
1149 /* Ensure all subprocesses (in particular, the output handling process)
1150 are complete before we pass this point. */
1151
1152 while (wait(&rc) >= 0);
1153
1154 DEBUG(D_transport) debug_printf("%s transport yielded %d\n", tblock->name,
1155 addr->transport_return);
1156
1157 /* If there has been a problem, the message in addr->message contains details
1158 of the pipe command. We don't want to expose these to the world, so we set up
1159 something bland to return to the sender. */
1160
1161 if (addr->transport_return != OK)
1162 addr->user_message = US"local delivery failed";
1163
1164 return FALSE;
1165 }
1166
1167 #endif /*!MACRO_PREDEF*/
1168 /* End of transport/pipe.c */