1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) The Exim maintainers 2020 - 2023 */
6 /* Copyright (c) University of Cambridge 1995 - 2018 */
7 /* See the file NOTICE for conditions of use and distribution. */
8 /* SPDX-License-Identifier: GPL-2.0-or-later */
14 #ifdef HAVE_SETCLASSRESOURCES
15 #include <login_cap.h>
20 /* Options specific to the pipe transport. They must be in alphabetic
21 order (note that "_" comes before the lower case letters). Those starting
22 with "*" are not settable by the user but are used by the option-reading
23 software for alternative value types. Some options are stored in the transport
24 instance block so as to be publicly visible; these are flagged with opt_public.
26 #define LOFF(field) OPT_OFF(pipe_transport_options_block, field)
28 optionlist pipe_transport_options[] = {
29 { "allow_commands", opt_stringptr, LOFF(allow_commands) },
30 { "batch_id", opt_stringptr | opt_public,
31 OPT_OFF(transport_instance, batch_id) },
32 { "batch_max", opt_int | opt_public,
33 OPT_OFF(transport_instance, batch_max) },
34 { "check_string", opt_stringptr, LOFF(check_string) },
35 { "command", opt_stringptr, LOFF(cmd) },
36 { "environment", opt_stringptr, LOFF(environment) },
37 { "escape_string", opt_stringptr, LOFF(escape_string) },
38 { "force_command", opt_bool, LOFF(force_command) },
39 { "freeze_exec_fail", opt_bool, LOFF(freeze_exec_fail) },
40 { "freeze_signal", opt_bool, LOFF(freeze_signal) },
41 { "ignore_status", opt_bool, LOFF(ignore_status) },
42 { "log_defer_output", opt_bool | opt_public,
43 OPT_OFF(transport_instance, log_defer_output) },
44 { "log_fail_output", opt_bool | opt_public,
45 OPT_OFF(transport_instance, log_fail_output) },
46 { "log_output", opt_bool | opt_public,
47 OPT_OFF(transport_instance, log_output) },
48 { "max_output", opt_mkint, LOFF(max_output) },
49 { "message_prefix", opt_stringptr, LOFF(message_prefix) },
50 { "message_suffix", opt_stringptr, LOFF(message_suffix) },
51 { "path", opt_stringptr, LOFF(path) },
52 { "permit_coredump", opt_bool, LOFF(permit_coredump) },
53 { "pipe_as_creator", opt_bool | opt_public,
54 OPT_OFF(transport_instance, deliver_as_creator) },
55 { "restrict_to_path", opt_bool, LOFF(restrict_to_path) },
56 { "return_fail_output",opt_bool | opt_public,
57 OPT_OFF(transport_instance, return_fail_output) },
58 { "return_output", opt_bool | opt_public,
59 OPT_OFF(transport_instance, return_output) },
60 { "temp_errors", opt_stringptr, LOFF(temp_errors) },
61 { "timeout", opt_time, LOFF(timeout) },
62 { "timeout_defer", opt_bool, LOFF(timeout_defer) },
63 { "umask", opt_octint, LOFF(umask) },
64 { "use_bsmtp", opt_bool, LOFF(use_bsmtp) },
65 #ifdef HAVE_SETCLASSRESOURCES
66 { "use_classresources", opt_bool, LOFF(use_classresources) },
68 { "use_crlf", opt_bool, LOFF(use_crlf) },
69 { "use_shell", opt_bool, LOFF(use_shell) },
72 /* Size of the options list. An extern variable has to be used so that its
73 address can appear in the tables drtables.c. */
75 int pipe_transport_options_count =
76 sizeof(pipe_transport_options)/sizeof(optionlist);
82 pipe_transport_options_block pipe_transport_option_defaults = {0};
83 void pipe_transport_init(transport_instance *tblock) {}
84 BOOL pipe_transport_entry(transport_instance *tblock, address_item *addr) {return FALSE;}
86 #else /*!MACRO_PREDEF*/
89 /* Default private options block for the pipe transport. */
91 pipe_transport_options_block pipe_transport_option_defaults = {
92 .path = US"/bin:/usr/bin",
93 .temp_errors = US mac_expanded_string(EX_TEMPFAIL) ":"
94 mac_expanded_string(EX_CANTCREAT),
98 /* all others null/zero/false */
103 /*************************************************
104 * Setup entry point *
105 *************************************************/
107 /* Called for each delivery in the privileged state, just before the uid/gid
108 are changed and the main entry point is called. In a system that supports the
109 login_cap facilities, this function is used to set the class resource limits
110 for the user. It may also re-enable coredumps.
113 tblock points to the transport instance
114 addrlist addresses about to be delivered (not used)
115 dummy not used (doesn't pass back data)
116 uid the uid that will be set (not used)
117 gid the gid that will be set (not used)
118 errmsg where to put an error message
120 Returns: OK, FAIL, or DEFER
124 pipe_transport_setup(transport_instance *tblock, address_item *addrlist,
125 transport_feedback *dummy, uid_t uid, gid_t gid, uschar **errmsg)
127 pipe_transport_options_block *ob =
128 (pipe_transport_options_block *)(tblock->options_block);
130 #ifdef HAVE_SETCLASSRESOURCES
131 if (ob->use_classresources)
133 struct passwd *pw = getpwuid(uid);
136 login_cap_t *lc = login_getpwclass(pw);
139 setclassresources(lc);
147 if (ob->permit_coredump)
150 rl.rlim_cur = RLIM_INFINITY;
151 rl.rlim_max = RLIM_INFINITY;
152 if (setrlimit(RLIMIT_CORE, &rl) < 0)
154 #ifdef SETRLIMIT_NOT_SUPPORTED
155 if (errno != ENOSYS && errno != ENOTSUP)
157 log_write(0, LOG_MAIN,
158 "delivery setrlimit(RLIMIT_CORE, RLIM_INFINITY) failed: %s",
169 /*************************************************
170 * Initialization entry point *
171 *************************************************/
173 /* Called for each instance, after its options have been read, to
174 enable consistency checks to be done, or anything else that needs
178 pipe_transport_init(transport_instance *tblock)
180 pipe_transport_options_block *ob =
181 (pipe_transport_options_block *)(tblock->options_block);
183 /* Set up the setup entry point, to be called in the privileged state */
185 tblock->setup = pipe_transport_setup;
187 /* If pipe_as_creator is set, then uid/gid should not be set. */
189 if (tblock->deliver_as_creator && (tblock->uid_set || tblock->gid_set ||
190 tblock->expand_uid != NULL || tblock->expand_gid != NULL))
191 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
192 "both pipe_as_creator and an explicit uid/gid are set for the %s "
193 "transport", tblock->name);
195 /* If a fixed uid field is set, then a gid field must also be set. */
197 if (tblock->uid_set && !tblock->gid_set && tblock->expand_gid == NULL)
198 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
199 "user set without group for the %s transport", tblock->name);
201 /* Temp_errors must consist only of digits and colons, but there can be
202 spaces round the colons, so allow them too. */
204 if (ob->temp_errors != NULL && Ustrcmp(ob->temp_errors, "*") != 0)
206 size_t p = Ustrspn(ob->temp_errors, "0123456789: ");
207 if (ob->temp_errors[p] != 0)
208 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
209 "temp_errors must be a list of numbers or an asterisk for the %s "
210 "transport", tblock->name);
213 /* Only one of return_output/return_fail_output or log_output/log_fail_output
216 if (tblock->return_output && tblock->return_fail_output)
217 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
218 "both return_output and return_fail_output set for %s transport",
221 if (tblock->log_output && tblock->log_fail_output)
222 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
223 "both log_output and log_fail_output set for the %s transport",
226 /* If batch SMTP is set, force the check and escape strings, and arrange that
227 headers are also escaped. */
231 ob->check_string = US".";
232 ob->escape_string = US"..";
233 ob->options |= topt_escape_headers;
236 /* If not batch SMTP, and message_prefix or message_suffix are unset, insert
237 default values for them. */
241 if (ob->message_prefix == NULL) ob->message_prefix =
242 US"From ${if def:return_path{$return_path}{MAILER-DAEMON}} ${tod_bsdinbox}\n";
243 if (ob->message_suffix == NULL) ob->message_suffix = US"\n";
246 /* The restrict_to_path and use_shell options are incompatible */
248 if (ob->restrict_to_path && ob->use_shell)
249 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
250 "both restrict_to_path and use_shell set for %s transport",
253 /* The allow_commands and use_shell options are incompatible */
255 if (ob->allow_commands && ob->use_shell)
256 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
257 "both allow_commands and use_shell set for %s transport",
260 /* Set up the bitwise options for transport_write_message from the various
261 driver options. Only one of body_only and headers_only can be set. */
264 (tblock->body_only ? topt_no_headers : 0)
265 | (tblock->headers_only ? topt_no_body : 0)
266 | (tblock->return_path_add ? topt_add_return_path : 0)
267 | (tblock->delivery_date_add ? topt_add_delivery_date : 0)
268 | (tblock->envelope_to_add ? topt_add_envelope_to : 0)
269 | (ob->use_crlf ? topt_use_crlf : 0);
274 /*************************************************
275 * Set up direct (non-shell) command *
276 *************************************************/
278 /* This function is called when a command line is to be parsed by the transport
279 and executed directly, without the use of /bin/sh.
282 argvptr pointer to anchor for argv vector
283 cmd points to the command string
284 expand_arguments true if expansion is to occur
285 expand_fail error if expansion fails
286 addr chain of addresses
287 tname the transport name
288 ob the transport options block
290 Returns: TRUE if all went well; otherwise an error will be
291 set in the first address and FALSE returned
295 set_up_direct_command(const uschar *** argvptr, const uschar * cmd,
296 BOOL expand_arguments, int expand_fail, address_item * addr, uschar * tname,
297 pipe_transport_options_block * ob)
299 BOOL permitted = FALSE;
302 /* Set up "transport <name>" to be put in any error messages, and then
303 call the common function for creating an argument list and expanding
304 the items if necessary. If it fails, this function fails (error information
305 is in the addresses). */
307 if (!transport_set_up_command(argvptr, cmd,
308 expand_arguments ? TSUC_EXPAND_ARGS : 0,
309 expand_fail, addr, string_sprintf("%.50s transport", tname), NULL))
312 /* Point to the set-up arguments. */
316 /* If allow_commands is set, see if the command is in the permitted list. */
318 if (ob->allow_commands)
324 if (!(s = expand_string(ob->allow_commands)))
326 addr->transport_return = DEFER;
327 addr->message = string_sprintf("failed to expand string \"%s\" "
328 "for %s transport: %s", ob->allow_commands, tname, expand_string_message);
332 while ((p = string_nextinlist(&s, &sep, NULL, 0)))
333 if (Ustrcmp(p, argv[0]) == 0) { permitted = TRUE; break; }
336 /* If permitted is TRUE it means the command was found in the allowed list, and
337 no further checks are done. If permitted = FALSE, it either means
338 allow_commands wasn't set, or that the command didn't match anything in the
339 list. In both cases, if restrict_to_path is set, we fail if the command
340 contains any slashes, but if restrict_to_path is not set, we must fail the
341 command only if allow_commands is set. */
345 if (ob->restrict_to_path)
347 if (Ustrchr(argv[0], '/') != NULL)
349 addr->transport_return = FAIL;
350 addr->message = string_sprintf("\"/\" found in \"%s\" (command for %s "
351 "transport) - failed for security reasons", cmd, tname);
356 else if (ob->allow_commands)
358 addr->transport_return = FAIL;
359 addr->message = string_sprintf("\"%s\" command not permitted by %s "
360 "transport", argv[0], tname);
365 /* If the command is not an absolute path, search the PATH directories
368 if (argv[0][0] != '/')
372 const uschar *listptr = expand_string(ob->path);
374 while ((p = string_nextinlist(&listptr, &sep, NULL, 0)))
377 sprintf(CS big_buffer, "%.256s/%.256s", p, argv[0]);
378 if (Ustat(big_buffer, &statbuf) == 0)
380 argv[0] = string_copy(big_buffer);
386 addr->transport_return = FAIL;
387 addr->message = string_sprintf("\"%s\" command not found for %s transport",
397 /*************************************************
398 * Set up shell command *
399 *************************************************/
401 /* This function is called when a command line is to be passed to /bin/sh
402 without parsing inside the transport.
405 argvptr pointer to anchor for argv vector
406 cmd points to the command string
407 expand_arguments true if expansion is to occur
408 expand_fail error if expansion fails
409 addr chain of addresses
410 tname the transport name
412 Returns: TRUE if all went well; otherwise an error will be
413 set in the first address and FALSE returned
417 set_up_shell_command(const uschar *** argvptr, const uschar * cmd,
418 BOOL expand_arguments, int expand_fail, address_item * addr, uschar * tname)
422 *argvptr = argv = store_get((4)*sizeof(uschar *), GET_UNTAINTED);
424 argv[0] = US"/bin/sh";
427 /* We have to take special action to handle the special "variable" called
428 $pipe_addresses, which is not recognized by the normal expansion function. */
430 if (expand_arguments)
432 uschar * p = Ustrstr(cmd, "pipe_addresses");
436 debug_printf("shell pipe command before expansion:\n %s\n", cmd);
438 /* Allow $recipients in the expansion iff it comes from a system filter */
440 f.enable_dollar_recipients = addr && addr->parent &&
441 Ustrcmp(addr->parent->address, "system-filter") == 0;
444 (p > cmd && p[-1] == '$') ||
445 (p > cmd + 1 && p[-2] == '$' && p[-1] == '{' && p[14] == '}')))
449 if (p[-1] == '{') { q++; p--; }
451 g = string_get(Ustrlen(cmd) + 64);
452 g = string_catn(g, cmd, p - cmd - 1);
454 for (address_item * ad = addr; ad; ad = ad->next)
456 DEBUG(D_transport) if (is_tainted(ad->address))
457 debug_printf("tainted element '%s' from $pipe_addresses\n", ad->address);
459 /*XXX string_append_listele() ? */
460 if (ad != addr) g = string_catn(g, US" ", 1);
461 g = string_cat(g, ad->address);
464 g = string_cat(g, q);
465 argv[2] = (cmd = string_from_gstring(g)) ? expand_cstring(cmd) : NULL;
468 argv[2] = expand_cstring(cmd);
470 f.enable_dollar_recipients = FALSE;
474 addr->transport_return = f.search_find_defer ? DEFER : expand_fail;
475 addr->message = string_sprintf("Expansion of command \"%s\" "
476 "in %s transport failed: %s",
477 cmd, tname, expand_string_message);
482 debug_printf("shell pipe command after expansion:\n %s\n", argv[2]);
487 debug_printf("shell pipe command (no expansion):\n %s\n", cmd);
498 /*************************************************
500 *************************************************/
502 /* See local README for interface details. This transport always returns FALSE,
503 indicating that the status in the first address is the status for all addresses
507 pipe_transport_entry(
508 transport_instance *tblock, /* data for this instantiation */
509 address_item *addr) /* address(es) we are working on */
512 int fd_in, fd_out, rc;
516 pipe_transport_options_block *ob =
517 (pipe_transport_options_block *)(tblock->options_block);
518 int timeout = ob->timeout;
519 BOOL written_ok = FALSE;
520 BOOL expand_arguments;
521 const uschar ** argv;
523 const uschar * envlist = ob->environment;
526 uschar * eol = ob->use_crlf ? US"\r\n" : US"\n";
527 transport_ctx tctx = {
530 .check_string = ob->check_string,
531 .escape_string = ob->escape_string,
532 ob->options | topt_not_socket /* set at initialization time */
535 DEBUG(D_transport) debug_printf("%s transport entered\n", tblock->name);
537 /* Set up for the good case */
539 addr->transport_return = OK;
540 addr->basic_errno = 0;
542 /* Pipes are not accepted as general addresses, but they can be generated from
543 .forward files or alias files. In those cases, the pfr flag is set, and the
544 command to be obeyed is pointed to by addr->local_part; it starts with the pipe
545 symbol. In other cases, the command is supplied as one of the pipe transport's
548 if (testflag(addr, af_pfr) && addr->local_part[0] == '|')
549 if (ob->force_command)
551 /* Enables expansion of $address_pipe into separate arguments */
552 setflag(addr, af_force_command);
554 expand_arguments = TRUE;
559 cmd = addr->local_part + 1;
560 while (isspace(*cmd)) cmd++;
561 expand_arguments = testflag(addr, af_expand_pipe);
567 expand_arguments = TRUE;
571 /* If no command has been supplied, we are in trouble.
572 We also check for an empty string since it may be
573 coming from addr->local_part[0] == '|' */
577 addr->transport_return = DEFER;
578 addr->message = string_sprintf("no command specified for %s transport",
584 DEBUG(D_transport) debug_printf("cmd '%s' is tainted\n", cmd);
585 addr->message = string_sprintf("Tainted '%s' (command "
586 "for %s transport) not permitted", cmd, tblock->name);
587 addr->transport_return = PANIC;
591 /* When a pipe is set up by a filter file, there may be values for $thisaddress
592 and numerical the variables in existence. These are passed in
593 addr->pipe_expandn for use here. */
595 if (expand_arguments && addr->pipe_expandn)
597 uschar **ss = addr->pipe_expandn;
599 if (*ss) filter_thisaddress = *ss++;
602 expand_nstring[++expand_nmax] = *ss;
603 expand_nlength[expand_nmax] = Ustrlen(*ss++);
607 /* The default way of processing the command is to split it up into arguments
608 here, and run it directly. This offers some security advantages. However, there
609 are installations that want by default to run commands under /bin/sh always, so
610 there is an option to do that. */
614 if (!set_up_shell_command(&argv, cmd, expand_arguments, expand_fail, addr,
615 tblock->name)) return FALSE;
617 else if (!set_up_direct_command(&argv, cmd, expand_arguments, expand_fail, addr,
618 tblock->name, ob)) return FALSE;
620 expand_nmax = -1; /* Reset */
621 filter_thisaddress = NULL;
623 /* Set up the environment for the command. */
625 envp[envcount++] = string_sprintf("LOCAL_PART=%s", deliver_localpart);
626 envp[envcount++] = string_sprintf("LOGNAME=%s", deliver_localpart);
627 envp[envcount++] = string_sprintf("USER=%s", deliver_localpart);
628 envp[envcount++] = string_sprintf("LOCAL_PART_PREFIX=%#s",
629 deliver_localpart_prefix);
630 envp[envcount++] = string_sprintf("LOCAL_PART_SUFFIX=%#s",
631 deliver_localpart_suffix);
632 envp[envcount++] = string_sprintf("DOMAIN=%s", deliver_domain);
633 envp[envcount++] = string_sprintf("HOME=%#s", deliver_home);
634 envp[envcount++] = string_sprintf("MESSAGE_ID=%s", message_id);
635 envp[envcount++] = string_sprintf("PATH=%s", expand_string(ob->path));
636 envp[envcount++] = string_sprintf("RECIPIENT=%#s%#s%#s@%#s",
637 deliver_localpart_prefix, deliver_localpart, deliver_localpart_suffix,
639 envp[envcount++] = string_sprintf("QUALIFY_DOMAIN=%s", qualify_domain_sender);
640 envp[envcount++] = string_sprintf("SENDER=%s", sender_address);
641 envp[envcount++] = US"SHELL=/bin/sh";
644 envp[envcount++] = string_sprintf("HOST=%s", addr->host_list->name);
646 if (f.timestamps_utc)
647 envp[envcount++] = US"TZ=UTC";
648 else if (timezone_string && timezone_string[0])
649 envp[envcount++] = string_sprintf("TZ=%s", timezone_string);
651 /* Add any requested items */
654 if (!(envlist = expand_cstring(envlist)))
656 addr->transport_return = DEFER;
657 addr->message = string_sprintf("failed to expand string \"%s\" "
658 "for %s transport: %s", ob->environment, tblock->name,
659 expand_string_message);
663 while ((ss = string_nextinlist(&envlist, &envsep, NULL, 0)))
665 if (envcount > nelem(envp) - 2)
667 addr->transport_return = DEFER;
668 addr->basic_errno = E2BIG;
669 addr->message = string_sprintf("too many environment settings for "
670 "%s transport", tblock->name);
673 envp[envcount++] = string_copy(ss);
676 envp[envcount] = NULL;
678 /* If the -N option is set, can't do any more. */
683 debug_printf("*** delivery by %s transport bypassed by -N option",
689 /* Handling the output from the pipe is tricky. If a file for catching this
690 output is provided, we could in theory just hand that fd over to the process,
691 but this isn't very safe because it might loop and carry on writing for
692 ever (which is exactly what happened in early versions of Exim). Therefore we
693 use the standard child_open() function, which creates pipes. We can then read
694 our end of the output pipe and count the number of bytes that come through,
695 chopping the sub-process if it exceeds some limit.
697 However, this means we want to run a sub-process with both its input and output
698 attached to pipes. We can't handle that easily from a single parent process
699 using straightforward code such as the transport_write_message() function
700 because the subprocess might not be reading its input because it is trying to
701 write to a full output pipe. The complication of redesigning the world to
702 handle this is too great - simpler just to run another process to do the
703 reading of the output pipe. */
706 /* As this is a local transport, we are already running with the required
707 uid/gid and current directory. Request that the new process be a process group
708 leader, so we can kill it and all its children on a timeout. */
710 if ((pid = child_open(USS argv, envp, ob->umask, &fd_in, &fd_out, TRUE,
711 US"pipe-tpt-cmd")) < 0)
713 addr->transport_return = DEFER;
714 addr->message = string_sprintf(
715 "Failed to create child process for %s transport: %s", tblock->name,
721 /* Now fork a process to handle the output that comes down the pipe. */
723 if ((outpid = exim_fork(US"pipe-tpt-output")) < 0)
725 addr->basic_errno = errno;
726 addr->transport_return = DEFER;
727 addr->message = string_sprintf(
728 "Failed to create process for handling output in %s transport",
735 /* This is the code for the output-handling subprocess. Read from the pipe
736 in chunks, and write to the return file if one is provided. Keep track of
737 the number of bytes handled. If the limit is exceeded, try to kill the
738 subprocess group, and in any case close the pipe and exit, which should cause
739 the subprocess to fail. */
745 set_process_info("reading output from |%s", cmd);
746 while ((rc = read(fd_out, big_buffer, big_buffer_size)) > 0)
748 if (addr->return_file >= 0)
749 if(write(addr->return_file, big_buffer, rc) != rc)
750 DEBUG(D_transport) debug_printf("Problem writing to return_file\n");
752 if (count > ob->max_output)
754 DEBUG(D_transport) debug_printf("Too much output from pipe - killed\n");
755 if (addr->return_file >= 0)
757 uschar *message = US"\n\n*** Too much output - remainder discarded ***\n";
758 rc = Ustrlen(message);
759 if(write(addr->return_file, message, rc) != rc)
760 DEBUG(D_transport) debug_printf("Problem writing to return_file\n");
762 killpg(pid, SIGKILL);
770 (void)close(fd_out); /* Not used in this process */
773 /* Carrying on now with the main parent process. Attempt to write the message
774 to it down the pipe. It is a fallacy to think that you can detect write errors
775 when the sub-process fails to read the pipe. The parent process may complete
776 writing and close the pipe before the sub-process completes. We could sleep a
777 bit here to let the sub-process get going, but it may still not complete. So we
778 ignore all writing errors. (When in the test harness, we do do a short sleep so
779 any debugging output is likely to be in the same order.) */
781 testharness_pause_ms(500);
783 DEBUG(D_transport) debug_printf("Writing message to pipe\n");
785 /* Arrange to time out writes if there is a timeout set. */
789 sigalrm_seen = FALSE;
790 transport_write_timeout = timeout;
793 /* Reset the counter of bytes written */
797 /* First write any configured prefix information */
799 if (ob->message_prefix)
801 uschar *prefix = expand_string(ob->message_prefix);
804 addr->transport_return = f.search_find_defer? DEFER : PANIC;
805 addr->message = string_sprintf("Expansion of \"%s\" (prefix for %s "
806 "transport) failed: %s", ob->message_prefix, tblock->name,
807 expand_string_message);
810 if (!transport_write_block(&tctx, prefix, Ustrlen(prefix), FALSE))
814 /* If the use_bsmtp option is set, we need to write SMTP prefix information.
815 The various different values for batching are handled outside; if there is more
816 than one address available here, all must be included. Force SMTP dot-handling.
821 if (!transport_write_string(fd_in, "MAIL FROM:<%s>%s", return_path, eol))
824 for (address_item * a = addr; a; a = a->next)
825 if (!transport_write_string(fd_in,
827 transport_rcpt_address(a, tblock->rcpt_include_affixes),
831 if (!transport_write_string(fd_in, "DATA%s", eol)) goto END_WRITE;
834 /* Now the actual message */
836 if (!transport_write_message(&tctx, 0))
839 /* Now any configured suffix */
841 if (ob->message_suffix)
843 uschar *suffix = expand_string(ob->message_suffix);
846 addr->transport_return = f.search_find_defer? DEFER : PANIC;
847 addr->message = string_sprintf("Expansion of \"%s\" (suffix for %s "
848 "transport) failed: %s", ob->message_suffix, tblock->name,
849 expand_string_message);
852 if (!transport_write_block(&tctx, suffix, Ustrlen(suffix), FALSE))
856 /* If local_smtp, write the terminating dot. */
858 if (ob->use_bsmtp && !transport_write_string(fd_in, ".%s", eol))
861 /* Flag all writing completed successfully. */
865 /* Come here if there are errors during writing. */
869 /* OK, the writing is now all done. Close the pipe. */
873 /* Handle errors during writing. For timeouts, set the timeout for waiting for
874 the child process to 1 second. If the process at the far end of the pipe died
875 without reading all of it, we expect an EPIPE error, which should be ignored.
876 We used also to ignore WRITEINCOMPLETE but the writing function is now cleverer
877 at handling OS where the death of a pipe doesn't give EPIPE immediately. See
882 if (errno == ETIMEDOUT)
884 addr->message = string_sprintf("%stimeout while writing to pipe",
885 f.transport_filter_timed_out ? "transport filter " : "");
886 addr->transport_return = ob->timeout_defer? DEFER : FAIL;
889 else if (errno == EPIPE)
891 debug_printf("transport error EPIPE ignored\n");
895 addr->transport_return = PANIC;
896 addr->basic_errno = errno;
897 if (errno == ERRNO_CHHEADER_FAIL)
899 string_sprintf("Failed to expand headers_add or headers_remove: %s",
900 expand_string_message);
901 else if (errno == ERRNO_FILTER_FAIL)
902 addr->message = string_sprintf("Transport filter process failed (%d)%s",
904 (addr->more_errno == EX_EXECFAILED)? ": unable to execute command" : "");
905 else if (errno == ERRNO_WRITEINCOMPLETE)
906 addr->message = US"Failed repeatedly to write data";
908 addr->message = string_sprintf("Error %d", errno);
913 /* Wait for the child process to complete and take action if the returned
914 status is nonzero. The timeout will be just 1 second if any of the writes
917 if ((rc = child_close(pid, timeout)) != 0)
919 uschar * tmsg = addr->message
920 ? string_sprintf(" (preceded by %s)", addr->message) : US"";
922 /* The process did not complete in time; kill its process group and fail
923 the delivery. It appears to be necessary to kill the output process too, as
924 otherwise it hangs on for some time if the actual pipe process is sleeping.
925 (At least, that's what I observed on Solaris 2.5.1.) Since we are failing
926 the delivery, that shouldn't cause any problem. */
930 killpg(pid, SIGKILL);
931 kill(outpid, SIGKILL);
932 addr->transport_return = ob->timeout_defer? DEFER : FAIL;
933 addr->message = string_sprintf("pipe delivery process timed out%s", tmsg);
940 addr->transport_return = PANIC;
941 addr->message = string_sprintf("Wait() failed for child process of %s "
942 "transport: %s%s", tblock->name, strerror(errno), tmsg);
945 /* Since the transport_filter timed out we assume it has sent the child process
946 a malformed or incomplete data stream. Kill off the child process
947 and prevent checking its exit status as it will has probably exited in error.
948 This prevents the transport_filter timeout message from getting overwritten
949 by the exit error which is not the cause of the problem. */
951 else if (f.transport_filter_timed_out)
953 killpg(pid, SIGKILL);
954 kill(outpid, SIGKILL);
957 /* Either the process completed, but yielded a non-zero (necessarily
958 positive) status, or the process was terminated by a signal (rc will contain
959 the negation of the signal number). Treat killing by signal as failure unless
960 status is being ignored. By default, the message is bounced back, unless
961 freeze_signal is set, in which case it is frozen instead. */
965 if (ob->freeze_signal)
967 addr->transport_return = DEFER;
968 addr->special_action = SPECIAL_FREEZE;
969 addr->message = string_sprintf("Child process of %s transport (running "
970 "command \"%s\") was terminated by signal %d (%s)%s", tblock->name, cmd,
971 -rc, os_strsignal(-rc), tmsg);
973 else if (!ob->ignore_status)
975 addr->transport_return = FAIL;
976 addr->message = string_sprintf("Child process of %s transport (running "
977 "command \"%s\") was terminated by signal %d (%s)%s", tblock->name, cmd,
978 -rc, os_strsignal(-rc), tmsg);
982 /* For positive values (process terminated with non-zero status), we need a
983 status code to request deferral. A number of systems contain the following
986 #define EX_TEMPFAIL 75
990 EX_TEMPFAIL -- temporary failure, indicating something that
991 is not really an error. In sendmail, this means
992 that a mailer (e.g.) could not create a connection,
993 and the request should be reattempted later.
995 Based on this, we use exit code EX_TEMPFAIL as a default to mean "defer" when
996 not ignoring the returned status. However, there is now an option that
997 contains a list of temporary codes, with TEMPFAIL and CANTCREAT as defaults.
999 Another case that needs special treatment is if execve() failed (typically
1000 the command that was given is a non-existent path). By default this is
1001 treated as just another failure, but if freeze_exec_fail is set, the reaction
1002 is to freeze the message rather than bounce the address. Exim used to signal
1003 this failure with EX_UNAVAILABLE, which is defined in many systems as
1005 #define EX_UNAVAILABLE 69
1007 with the description
1009 EX_UNAVAILABLE -- A service is unavailable. This can occur
1010 if a support program or file does not exist. This
1011 can also be used as a catchall message when something
1012 you wanted to do doesn't work, but you don't know why.
1014 However, this can be confused with a command that actually returns 69 because
1015 something *it* wanted is unavailable. At release 4.21, Exim was changed to
1016 use return code 127 instead, because this is what the shell returns when it
1017 is unable to exec a command. We define it as EX_EXECFAILED, and use it in
1018 child.c to signal execve() failure and other unexpected failures such as
1019 setuid() not working - though that won't be the case here because we aren't
1024 /* Always handle execve() failure specially if requested to */
1026 if (ob->freeze_exec_fail && rc == EX_EXECFAILED)
1028 addr->transport_return = DEFER;
1029 addr->special_action = SPECIAL_FREEZE;
1030 addr->message = string_sprintf("pipe process failed to exec \"%s\"%s",
1034 /* Otherwise take action only if not ignoring status */
1036 else if (!ob->ignore_status)
1041 /* If temp_errors is "*" all codes are temporary. Initialization checks
1042 that it's either "*" or a list of numbers. If not "*", scan the list of
1043 temporary failure codes; if any match, the result is DEFER. */
1045 if (ob->temp_errors[0] == '*')
1046 addr->transport_return = DEFER;
1050 const uschar *s = ob->temp_errors;
1054 addr->transport_return = FAIL;
1055 while ((p = string_nextinlist(&s,&sep,NULL,0)))
1056 if (rc == Uatoi(p)) { addr->transport_return = DEFER; break; }
1059 /* Ensure the message contains the expanded command and arguments. This
1060 doesn't have to be brilliantly efficient - it is an error situation. */
1062 addr->message = string_sprintf("Child process of %s transport returned "
1063 "%d", tblock->name, rc);
1064 g = string_cat(NULL, addr->message);
1066 /* If the return code is > 128, it often means that a shell command
1067 was terminated by a signal. */
1070 string_sprintf("(could mean shell command ended by signal %d (%s))",
1071 rc-128, os_strsignal(rc-128)) :
1076 g = string_catn(g, US" ", 1);
1077 g = string_cat (g, ss);
1080 /* Now add the command and arguments */
1082 g = string_catn(g, US" from command:", 14);
1084 for (int i = 0; i < sizeof(argv)/sizeof(int *) && argv[i] != NULL; i++)
1087 g = string_catn(g, US" ", 1);
1088 if (Ustrpbrk(argv[i], " \t") != NULL)
1091 g = string_catn(g, US"\"", 1);
1093 g = string_cat(g, argv[i]);
1095 g = string_catn(g, US"\"", 1);
1098 /* Add previous filter timeout message, if present. */
1101 g = string_cat(g, tmsg);
1103 addr->message = string_from_gstring(g);
1108 /* Ensure all subprocesses (in particular, the output handling process)
1109 are complete before we pass this point. */
1111 while (wait(&rc) >= 0);
1113 DEBUG(D_transport) debug_printf("%s transport yielded %d\n", tblock->name,
1114 addr->transport_return);
1116 /* If there has been a problem, the message in addr->message contains details
1117 of the pipe command. We don't want to expose these to the world, so we set up
1118 something bland to return to the sender. */
1120 if (addr->transport_return != OK)
1121 addr->user_message = US"local delivery failed";
1126 #endif /*!MACRO_PREDEF*/
1127 /* End of transport/pipe.c */