Pipe transport: expand the path option
[exim.git] / src / src / transports / pipe.c
CommitLineData
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1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
bfe645c1 5/* Copyright (c) University of Cambridge 1995 - 2015 */
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6/* See the file NOTICE for conditions of use and distribution. */
7
8
9#include "../exim.h"
10#include "pipe.h"
11
79378e0f 12#ifdef HAVE_SETCLASSRESOURCES
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13#include <login_cap.h>
14#endif
15
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16
17
18/* Options specific to the pipe transport. They must be in alphabetic
19order (note that "_" comes before the lower case letters). Those starting
20with "*" are not settable by the user but are used by the option-reading
21software for alternative value types. Some options are stored in the transport
22instance block so as to be publicly visible; these are flagged with opt_public.
23*/
24
25optionlist 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) },
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40 { "force_command", opt_bool,
41 (void *)offsetof(pipe_transport_options_block, force_command) },
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42 { "freeze_exec_fail", opt_bool,
43 (void *)offsetof(pipe_transport_options_block, freeze_exec_fail) },
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44 { "freeze_signal", opt_bool,
45 (void *)offsetof(pipe_transport_options_block, freeze_signal) },
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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) },
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62 { "permit_coredump", opt_bool,
63 (void *)offsetof(pipe_transport_options_block, permit_coredump) },
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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) },
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76 { "timeout_defer", opt_bool,
77 (void *)offsetof(pipe_transport_options_block, timeout_defer) },
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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) },
79378e0f 82 #ifdef HAVE_SETCLASSRESOURCES
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83 { "use_classresources", opt_bool,
84 (void *)offsetof(pipe_transport_options_block, use_classresources) },
85 #endif
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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
93address can appear in the tables drtables.c. */
94
95int pipe_transport_options_count =
96 sizeof(pipe_transport_options)/sizeof(optionlist);
97
98/* Default private options block for the pipe transport. */
99
100pipe_transport_options_block pipe_transport_option_defaults = {
101 NULL, /* cmd */
102 NULL, /* allow_commands */
103 NULL, /* environment */
cb741023 104 US"/bin:/usr/bin", /* path */
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105 NULL, /* message_prefix (reset in init if not bsmtp) */
106 NULL, /* message_suffix (ditto) */
107 US mac_expanded_string(EX_TEMPFAIL) ":" /* temp_errors */
108 mac_expanded_string(EX_CANTCREAT),
109 NULL, /* check_string */
110 NULL, /* escape_string */
111 022, /* umask */
112 20480, /* max_output */
113 60*60, /* timeout */
114 0, /* options */
09792322 115 FALSE, /* force_command */
0756eb3c 116 FALSE, /* freeze_exec_fail */
2fe76745 117 FALSE, /* freeze_signal */
0756eb3c 118 FALSE, /* ignore_status */
a29e5231 119 FALSE, /* permit_coredump */
0756eb3c 120 FALSE, /* restrict_to_path */
2e2a30b4 121 FALSE, /* timeout_defer */
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122 FALSE, /* use_shell */
123 FALSE, /* use_bsmtp */
929ba01c 124 FALSE, /* use_classresources */
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125 FALSE /* use_crlf */
126};
127
128
129
130/*************************************************
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131* Setup entry point *
132*************************************************/
133
134/* Called for each delivery in the privileged state, just before the uid/gid
135are changed and the main entry point is called. In a system that supports the
136login_cap facilities, this function is used to set the class resource limits
a29e5231 137for the user. It may also re-enable coredumps.
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138
139Arguments:
140 tblock points to the transport instance
141 addrlist addresses about to be delivered (not used)
142 dummy not used (doesn't pass back data)
143 uid the uid that will be set (not used)
144 gid the gid that will be set (not used)
145 errmsg where to put an error message
146
147Returns: OK, FAIL, or DEFER
148*/
149
150static int
151pipe_transport_setup(transport_instance *tblock, address_item *addrlist,
152 transport_feedback *dummy, uid_t uid, gid_t gid, uschar **errmsg)
153{
154pipe_transport_options_block *ob =
155 (pipe_transport_options_block *)(tblock->options_block);
156
157addrlist = addrlist; /* Keep compiler happy */
158dummy = dummy;
159uid = uid;
160gid = gid;
161errmsg = errmsg;
162ob = ob;
163
79378e0f 164#ifdef HAVE_SETCLASSRESOURCES
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165if (ob->use_classresources)
166 {
167 struct passwd *pw = getpwuid(uid);
168 if (pw != NULL)
169 {
170 login_cap_t *lc = login_getpwclass(pw);
171 if (lc != NULL)
172 {
173 setclassresources(lc);
174 login_close(lc);
175 }
176 }
177 }
178#endif
179
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180#ifdef RLIMIT_CORE
181if (ob->permit_coredump)
182 {
183 struct rlimit rl;
184 rl.rlim_cur = RLIM_INFINITY;
185 rl.rlim_max = RLIM_INFINITY;
186 if (setrlimit(RLIMIT_CORE, &rl) < 0)
187 {
188#ifdef SETRLIMIT_NOT_SUPPORTED
189 if (errno != ENOSYS && errno != ENOTSUP)
190#endif
191 log_write(0, LOG_MAIN,
762ca6f3 192 "delivery setrlimit(RLIMIT_CORE, RLIM_INFINITY) failed: %s",
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193 strerror(errno));
194 }
195 }
196#endif
197
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198return OK;
199}
200
201
202
203/*************************************************
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204* Initialization entry point *
205*************************************************/
206
207/* Called for each instance, after its options have been read, to
208enable consistency checks to be done, or anything else that needs
209to be set up. */
210
211void
212pipe_transport_init(transport_instance *tblock)
213{
214pipe_transport_options_block *ob =
215 (pipe_transport_options_block *)(tblock->options_block);
216
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217/* Set up the setup entry point, to be called in the privileged state */
218
219tblock->setup = pipe_transport_setup;
220
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221/* If pipe_as_creator is set, then uid/gid should not be set. */
222
223if (tblock->deliver_as_creator && (tblock->uid_set || tblock->gid_set ||
224 tblock->expand_uid != NULL || tblock->expand_gid != NULL))
225 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
226 "both pipe_as_creator and an explicit uid/gid are set for the %s "
227 "transport", tblock->name);
228
229/* If a fixed uid field is set, then a gid field must also be set. */
230
231if (tblock->uid_set && !tblock->gid_set && tblock->expand_gid == NULL)
232 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
233 "user set without group for the %s transport", tblock->name);
234
235/* Temp_errors must consist only of digits and colons, but there can be
236spaces round the colons, so allow them too. */
237
238if (ob->temp_errors != NULL && Ustrcmp(ob->temp_errors, "*") != 0)
239 {
240 size_t p = Ustrspn(ob->temp_errors, "0123456789: ");
241 if (ob->temp_errors[p] != 0)
242 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
243 "temp_errors must be a list of numbers or an asterisk for the %s "
244 "transport", tblock->name);
245 }
246
247/* Only one of return_output/return_fail_output or log_output/log_fail_output
248should be set. */
249
250if (tblock->return_output && tblock->return_fail_output)
251 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
252 "both return_output and return_fail_output set for %s transport",
253 tblock->name);
254
255if (tblock->log_output && tblock->log_fail_output)
256 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
257 "both log_output and log_fail_output set for the %s transport",
258 tblock->name);
259
260/* If batch SMTP is set, force the check and escape strings, and arrange that
261headers are also escaped. */
262
263if (ob->use_bsmtp)
264 {
265 ob->check_string = US".";
266 ob->escape_string = US"..";
267 ob->options |= topt_escape_headers;
268 }
269
270/* If not batch SMTP, and message_prefix or message_suffix are unset, insert
271default values for them. */
272
273else
274 {
275 if (ob->message_prefix == NULL) ob->message_prefix =
276 US"From ${if def:return_path{$return_path}{MAILER-DAEMON}} ${tod_bsdinbox}\n";
277 if (ob->message_suffix == NULL) ob->message_suffix = US"\n";
278 }
279
280/* The restrict_to_path and use_shell options are incompatible */
281
282if (ob->restrict_to_path && ob->use_shell)
283 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
284 "both restrict_to_path and use_shell set for %s transport",
285 tblock->name);
286
287/* The allow_commands and use_shell options are incompatible */
288
289if (ob->allow_commands && ob->use_shell)
290 log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
291 "both allow_commands and use_shell set for %s transport",
292 tblock->name);
293
294/* Set up the bitwise options for transport_write_message from the various
295driver options. Only one of body_only and headers_only can be set. */
296
297ob->options |=
298 (tblock->body_only? topt_no_headers : 0) |
299 (tblock->headers_only? topt_no_body : 0) |
300 (tblock->return_path_add? topt_add_return_path : 0) |
301 (tblock->delivery_date_add? topt_add_delivery_date : 0) |
302 (tblock->envelope_to_add? topt_add_envelope_to : 0) |
303 (ob->use_crlf? topt_use_crlf : 0);
304}
305
306
307
308/*************************************************
309* Set up direct (non-shell) command *
310*************************************************/
311
312/* This function is called when a command line is to be parsed by the transport
313and executed directly, without the use of /bin/sh.
314
315Arguments:
316 argvptr pointer to anchor for argv vector
317 cmd points to the command string
318 expand_arguments true if expansion is to occur
319 expand_fail error if expansion fails
320 addr chain of addresses
321 tname the transport name
322 ob the transport options block
323
324Returns: TRUE if all went well; otherwise an error will be
325 set in the first address and FALSE returned
326*/
327
328static BOOL
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329set_up_direct_command(const uschar ***argvptr, uschar *cmd,
330 BOOL expand_arguments, int expand_fail, address_item *addr, uschar *tname,
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331 pipe_transport_options_block *ob)
332{
333BOOL permitted = FALSE;
bfe645c1 334const uschar **argv;
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335
336/* Set up "transport <name>" to be put in any error messages, and then
337call the common function for creating an argument list and expanding
338the items if necessary. If it fails, this function fails (error information
339is in the addresses). */
340
0756eb3c 341if (!transport_set_up_command(argvptr, cmd, expand_arguments, expand_fail,
a94bdef3 342 addr, string_sprintf("%.50s transport", tname), NULL))
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343 return FALSE;
344
345/* Point to the set-up arguments. */
346
347argv = *argvptr;
348
349/* If allow_commands is set, see if the command is in the permitted list. */
350
a94bdef3 351if (ob->allow_commands)
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352 {
353 int sep = 0;
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354 const uschar *s;
355 uschar *p;
0756eb3c 356
bfe645c1 357 if (!(s = expand_string(ob->allow_commands)))
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358 {
359 addr->transport_return = DEFER;
360 addr->message = string_sprintf("failed to expand string \"%s\" "
361 "for %s transport: %s", ob->allow_commands, tname, expand_string_message);
362 return FALSE;
363 }
364
a94bdef3 365 while ((p = string_nextinlist(&s, &sep, NULL, 0)))
0756eb3c 366 if (Ustrcmp(p, argv[0]) == 0) { permitted = TRUE; break; }
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367 }
368
369/* If permitted is TRUE it means the command was found in the allowed list, and
370no further checks are done. If permitted = FALSE, it either means
371allow_commands wasn't set, or that the command didn't match anything in the
372list. In both cases, if restrict_to_path is set, we fail if the command
373contains any slashes, but if restrict_to_path is not set, we must fail the
374command only if allow_commands is set. */
375
376if (!permitted)
377 {
378 if (ob->restrict_to_path)
379 {
380 if (Ustrchr(argv[0], '/') != NULL)
381 {
382 addr->transport_return = FAIL;
383 addr->message = string_sprintf("\"/\" found in \"%s\" (command for %s "
384 "transport) - failed for security reasons", cmd, tname);
385 return FALSE;
386 }
387 }
388
a94bdef3 389 else if (ob->allow_commands)
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390 {
391 addr->transport_return = FAIL;
392 addr->message = string_sprintf("\"%s\" command not permitted by %s "
393 "transport", argv[0], tname);
394 return FALSE;
395 }
396 }
397
398/* If the command is not an absolute path, search the PATH directories
399for it. */
400
401if (argv[0][0] != '/')
402 {
403 int sep = 0;
404 uschar *p;
a94bdef3 405 const uschar *listptr = expand_string(ob->path);
0756eb3c 406
a94bdef3 407 while ((p = string_nextinlist(&listptr, &sep, NULL, 0)))
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408 {
409 struct stat statbuf;
410 sprintf(CS big_buffer, "%.256s/%.256s", p, argv[0]);
411 if (Ustat(big_buffer, &statbuf) == 0)
412 {
413 argv[0] = string_copy(big_buffer);
414 break;
415 }
416 }
a94bdef3 417 if (!p)
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418 {
419 addr->transport_return = FAIL;
420 addr->message = string_sprintf("\"%s\" command not found for %s transport",
421 argv[0], tname);
422 return FALSE;
423 }
424 }
425
426return TRUE;
427}
428
429
430/*************************************************
431* Set up shell command *
432*************************************************/
433
434/* This function is called when a command line is to be passed to /bin/sh
435without parsing inside the transport.
436
437Arguments:
438 argvptr pointer to anchor for argv vector
439 cmd points to the command string
440 expand_arguments true if expansion is to occur
441 expand_fail error if expansion fails
442 addr chain of addresses
443 tname the transport name
444
445Returns: TRUE if all went well; otherwise an error will be
446 set in the first address and FALSE returned
447*/
448
449static BOOL
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450set_up_shell_command(const uschar ***argvptr, uschar *cmd,
451 BOOL expand_arguments, int expand_fail, address_item *addr, uschar *tname)
0756eb3c 452{
bfe645c1 453const uschar **argv;
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454
455*argvptr = argv = store_get((4)*sizeof(uschar *));
456
457argv[0] = US"/bin/sh";
458argv[1] = US"-c";
459
460/* We have to take special action to handle the special "variable" called
461$pipe_addresses, which is not recognized by the normal expansion function. */
462
463DEBUG(D_transport)
464 debug_printf("shell pipe command before expansion:\n %s\n", cmd);
465
466if (expand_arguments)
467 {
468 uschar *s = cmd;
469 uschar *p = Ustrstr(cmd, "pipe_addresses");
470
471 if (p != NULL && (
472 (p > cmd && p[-1] == '$') ||
473 (p > cmd + 1 && p[-2] == '$' && p[-1] == '{' && p[14] == '}')))
474 {
475 address_item *ad;
476 uschar *q = p + 14;
477 int size = Ustrlen(cmd) + 64;
478 int offset;
479
480 if (p[-1] == '{') { q++; p--; }
481
482 s = store_get(size);
483 offset = p - cmd - 1;
484 Ustrncpy(s, cmd, offset);
485
486 for (ad = addr; ad != NULL; ad = ad->next)
487 {
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488 /*XXX string_append_listele() ? */
489 if (ad != addr) s = string_catn(s, &size, &offset, US" ", 1);
490 s = string_cat(s, &size, &offset, ad->address);
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491 }
492
4fab92fb 493 s = string_cat(s, &size, &offset, q);
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494 s[offset] = 0;
495 }
496
497 /* Allow $recipients in the expansion iff it comes from a system filter */
498
499 enable_dollar_recipients = addr != NULL &&
500 addr->parent != NULL &&
501 Ustrcmp(addr->parent->address, "system-filter") == 0;
502 argv[2] = expand_string(s);
503 enable_dollar_recipients = FALSE;
504
505 if (argv[2] == NULL)
506 {
507 addr->transport_return = search_find_defer? DEFER : expand_fail;
508 addr->message = string_sprintf("Expansion of command \"%s\" "
509 "in %s transport failed: %s",
510 cmd, tname, expand_string_message);
511 return FALSE;
512 }
513
514 DEBUG(D_transport)
515 debug_printf("shell pipe command after expansion:\n %s\n", argv[2]);
516 }
517else argv[2] = cmd;
518
519argv[3] = (uschar *)0;
520return TRUE;
521}
522
523
524
525
526/*************************************************
527* Main entry point *
528*************************************************/
529
530/* See local README for interface details. This transport always returns FALSE,
531indicating that the status in the first address is the status for all addresses
532in a batch. */
533
534BOOL
535pipe_transport_entry(
536 transport_instance *tblock, /* data for this instantiation */
537 address_item *addr) /* address(es) we are working on */
538{
539pid_t pid, outpid;
540int fd_in, fd_out, rc;
541int envcount = 0;
542int envsep = 0;
543int expand_fail;
544pipe_transport_options_block *ob =
545 (pipe_transport_options_block *)(tblock->options_block);
546int timeout = ob->timeout;
547BOOL written_ok = FALSE;
548BOOL expand_arguments;
bfe645c1 549const uschar **argv;
0756eb3c 550uschar *envp[50];
bfe645c1 551const uschar *envlist = ob->environment;
0756eb3c 552uschar *cmd, *ss;
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553uschar *eol = ob->use_crlf ? US"\r\n" : US"\n";
554transport_ctx tctx = {
555 tblock,
556 addr,
557 ob->check_string,
558 ob->escape_string,
559 ob->options /* set at initialization time */
560};
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561
562DEBUG(D_transport) debug_printf("%s transport entered\n", tblock->name);
563
564/* Set up for the good case */
565
566addr->transport_return = OK;
567addr->basic_errno = 0;
568
569/* Pipes are not accepted as general addresses, but they can be generated from
570.forward files or alias files. In those cases, the pfr flag is set, and the
571command to be obeyed is pointed to by addr->local_part; it starts with the pipe
572symbol. In other cases, the command is supplied as one of the pipe transport's
573options. */
574
575if (testflag(addr, af_pfr) && addr->local_part[0] == '|')
576 {
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PP
577 if (ob->force_command)
578 {
579 /* Enables expansion of $address_pipe into seperate arguments */
580 setflag(addr, af_force_command);
581 cmd = ob->cmd;
582 expand_arguments = TRUE;
583 expand_fail = PANIC;
584 }
585 else
586 {
587 cmd = addr->local_part + 1;
588 while (isspace(*cmd)) cmd++;
589 expand_arguments = testflag(addr, af_expand_pipe);
590 expand_fail = FAIL;
09792322 591 }
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592 }
593else
594 {
595 cmd = ob->cmd;
596 expand_arguments = TRUE;
597 expand_fail = PANIC;
598 }
599
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600/* If no command has been supplied, we are in trouble.
601 * We also check for an empty string since it may be
602 * coming from addr->local_part[0] == '|'
603 */
0756eb3c 604
09792322 605if (cmd == NULL || *cmd == '\0')
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PH
606 {
607 addr->transport_return = DEFER;
608 addr->message = string_sprintf("no command specified for %s transport",
609 tblock->name);
610 return FALSE;
611 }
612
613/* When a pipe is set up by a filter file, there may be values for $thisaddress
614and numerical the variables in existence. These are passed in
615addr->pipe_expandn for use here. */
616
a94bdef3 617if (expand_arguments && addr->pipe_expandn)
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618 {
619 uschar **ss = addr->pipe_expandn;
620 expand_nmax = -1;
621 if (*ss != NULL) filter_thisaddress = *ss++;
622 while (*ss != NULL)
623 {
624 expand_nstring[++expand_nmax] = *ss;
625 expand_nlength[expand_nmax] = Ustrlen(*ss++);
626 }
627 }
628
629/* The default way of processing the command is to split it up into arguments
630here, and run it directly. This offers some security advantages. However, there
631are installations that want by default to run commands under /bin/sh always, so
632there is an option to do that. */
633
634if (ob->use_shell)
635 {
636 if (!set_up_shell_command(&argv, cmd, expand_arguments, expand_fail, addr,
637 tblock->name)) return FALSE;
638 }
639else if (!set_up_direct_command(&argv, cmd, expand_arguments, expand_fail, addr,
640 tblock->name, ob)) return FALSE;
641
642expand_nmax = -1; /* Reset */
643filter_thisaddress = NULL;
644
645/* Set up the environment for the command. */
646
647envp[envcount++] = string_sprintf("LOCAL_PART=%s", deliver_localpart);
648envp[envcount++] = string_sprintf("LOGNAME=%s", deliver_localpart);
649envp[envcount++] = string_sprintf("USER=%s", deliver_localpart);
650envp[envcount++] = string_sprintf("LOCAL_PART_PREFIX=%#s",
651 deliver_localpart_prefix);
652envp[envcount++] = string_sprintf("LOCAL_PART_SUFFIX=%#s",
653 deliver_localpart_suffix);
654envp[envcount++] = string_sprintf("DOMAIN=%s", deliver_domain);
655envp[envcount++] = string_sprintf("HOME=%#s", deliver_home);
656envp[envcount++] = string_sprintf("MESSAGE_ID=%s", message_id);
a94bdef3 657envp[envcount++] = string_sprintf("PATH=%s", expand_string(ob->path));
0756eb3c
PH
658envp[envcount++] = string_sprintf("RECIPIENT=%#s%#s%#s@%#s",
659 deliver_localpart_prefix, deliver_localpart, deliver_localpart_suffix,
660 deliver_domain);
661envp[envcount++] = string_sprintf("QUALIFY_DOMAIN=%s", qualify_domain_sender);
662envp[envcount++] = string_sprintf("SENDER=%s", sender_address);
663envp[envcount++] = US"SHELL=/bin/sh";
664
665if (addr->host_list != NULL)
666 envp[envcount++] = string_sprintf("HOST=%s", addr->host_list->name);
667
668if (timestamps_utc) envp[envcount++] = US"TZ=UTC";
669else if (timezone_string != NULL && timezone_string[0] != 0)
670 envp[envcount++] = string_sprintf("TZ=%s", timezone_string);
671
672/* Add any requested items */
673
bfe645c1 674if (envlist)
0756eb3c 675 {
bfe645c1 676 envlist = expand_cstring(envlist);
0756eb3c
PH
677 if (envlist == NULL)
678 {
679 addr->transport_return = DEFER;
680 addr->message = string_sprintf("failed to expand string \"%s\" "
681 "for %s transport: %s", ob->environment, tblock->name,
682 expand_string_message);
683 return FALSE;
684 }
685 }
686
687while ((ss = string_nextinlist(&envlist, &envsep, big_buffer, big_buffer_size))
688 != NULL)
689 {
690 if (envcount > sizeof(envp)/sizeof(uschar *) - 2)
691 {
692 addr->transport_return = DEFER;
693 addr->message = string_sprintf("too many environment settings for "
694 "%s transport", tblock->name);
695 return FALSE;
696 }
697 envp[envcount++] = string_copy(ss);
698 }
699
700envp[envcount] = NULL;
701
702/* If the -N option is set, can't do any more. */
703
704if (dont_deliver)
705 {
706 DEBUG(D_transport)
707 debug_printf("*** delivery by %s transport bypassed by -N option",
708 tblock->name);
709 return FALSE;
710 }
711
712
713/* Handling the output from the pipe is tricky. If a file for catching this
714output is provided, we could in theory just hand that fd over to the process,
715but this isn't very safe because it might loop and carry on writing for
716ever (which is exactly what happened in early versions of Exim). Therefore we
717use the standard child_open() function, which creates pipes. We can then read
718our end of the output pipe and count the number of bytes that come through,
719chopping the sub-process if it exceeds some limit.
720
721However, this means we want to run a sub-process with both its input and output
722attached to pipes. We can't handle that easily from a single parent process
723using straightforward code such as the transport_write_message() function
724because the subprocess might not be reading its input because it is trying to
725write to a full output pipe. The complication of redesigning the world to
726handle this is too great - simpler just to run another process to do the
727reading of the output pipe. */
728
729
730/* As this is a local transport, we are already running with the required
731uid/gid and current directory. Request that the new process be a process group
732leader, so we can kill it and all its children on a timeout. */
733
bfe645c1 734if ((pid = child_open(USS argv, envp, ob->umask, &fd_in, &fd_out, TRUE)) < 0)
0756eb3c
PH
735 {
736 addr->transport_return = DEFER;
737 addr->message = string_sprintf(
738 "Failed to create child process for %s transport: %s", tblock->name,
739 strerror(errno));
740 return FALSE;
741 }
742
743/* Now fork a process to handle the output that comes down the pipe. */
744
745if ((outpid = fork()) < 0)
746 {
747 addr->basic_errno = errno;
748 addr->transport_return = DEFER;
749 addr->message = string_sprintf(
750 "Failed to create process for handling output in %s transport",
751 tblock->name);
f1e894f3
PH
752 (void)close(fd_in);
753 (void)close(fd_out);
0756eb3c
PH
754 return FALSE;
755 }
756
757/* This is the code for the output-handling subprocess. Read from the pipe
758in chunks, and write to the return file if one is provided. Keep track of
759the number of bytes handled. If the limit is exceeded, try to kill the
760subprocess group, and in any case close the pipe and exit, which should cause
761the subprocess to fail. */
762
763if (outpid == 0)
764 {
765 int count = 0;
f1e894f3 766 (void)close(fd_in);
0756eb3c
PH
767 set_process_info("reading output from |%s", cmd);
768 while ((rc = read(fd_out, big_buffer, big_buffer_size)) > 0)
769 {
770 if (addr->return_file >= 0)
1ac6b2e7
JH
771 if(write(addr->return_file, big_buffer, rc) != rc)
772 DEBUG(D_transport) debug_printf("Problem writing to return_file\n");
0756eb3c
PH
773 count += rc;
774 if (count > ob->max_output)
775 {
0756eb3c
PH
776 DEBUG(D_transport) debug_printf("Too much output from pipe - killed\n");
777 if (addr->return_file >= 0)
1ac6b2e7
JH
778 {
779 uschar *message = US"\n\n*** Too much output - remainder discarded ***\n";
780 rc = Ustrlen(message);
781 if(write(addr->return_file, message, rc) != rc)
782 DEBUG(D_transport) debug_printf("Problem writing to return_file\n");
783 }
0756eb3c
PH
784 killpg(pid, SIGKILL);
785 break;
786 }
787 }
f1e894f3 788 (void)close(fd_out);
0756eb3c
PH
789 _exit(0);
790 }
791
f1e894f3 792(void)close(fd_out); /* Not used in this process */
0756eb3c
PH
793
794
795/* Carrying on now with the main parent process. Attempt to write the message
796to it down the pipe. It is a fallacy to think that you can detect write errors
797when the sub-process fails to read the pipe. The parent process may complete
798writing and close the pipe before the sub-process completes. We could sleep a
799bit here to let the sub-process get going, but it may still not complete. So we
800ignore all writing errors. (When in the test harness, we do do a short sleep so
801any debugging output is likely to be in the same order.) */
802
803if (running_in_test_harness) millisleep(500);
804
805DEBUG(D_transport) debug_printf("Writing message to pipe\n");
806
807/* Arrange to time out writes if there is a timeout set. */
808
809if (timeout > 0)
810 {
811 sigalrm_seen = FALSE;
812 transport_write_timeout = timeout;
813 }
814
815/* Reset the counter of bytes written */
816
817transport_count = 0;
818
819/* First write any configured prefix information */
820
821if (ob->message_prefix != NULL)
822 {
823 uschar *prefix = expand_string(ob->message_prefix);
824 if (prefix == NULL)
825 {
826 addr->transport_return = search_find_defer? DEFER : PANIC;
827 addr->message = string_sprintf("Expansion of \"%s\" (prefix for %s "
828 "transport) failed: %s", ob->message_prefix, tblock->name,
829 expand_string_message);
830 return FALSE;
831 }
832 if (!transport_write_block(fd_in, prefix, Ustrlen(prefix)))
833 goto END_WRITE;
834 }
835
836/* If the use_bsmtp option is set, we need to write SMTP prefix information.
837The various different values for batching are handled outside; if there is more
838than one address available here, all must be included. Force SMTP dot-handling.
839*/
840
841if (ob->use_bsmtp)
842 {
843 address_item *a;
844
845 if (!transport_write_string(fd_in, "MAIL FROM:<%s>%s", return_path, eol))
846 goto END_WRITE;
847
4fab92fb 848 for (a = addr; a; a = a->next)
0756eb3c
PH
849 if (!transport_write_string(fd_in,
850 "RCPT TO:<%s>%s",
851 transport_rcpt_address(a, tblock->rcpt_include_affixes),
852 eol))
853 goto END_WRITE;
0756eb3c
PH
854
855 if (!transport_write_string(fd_in, "DATA%s", eol)) goto END_WRITE;
856 }
857
4fab92fb 858/* Now the actual message */
0756eb3c 859
4fab92fb 860if (!transport_write_message(fd_in, &tctx, 0))
0756eb3c
PH
861 goto END_WRITE;
862
863/* Now any configured suffix */
864
a94bdef3 865if (ob->message_suffix)
0756eb3c
PH
866 {
867 uschar *suffix = expand_string(ob->message_suffix);
a94bdef3 868 if (!suffix)
0756eb3c
PH
869 {
870 addr->transport_return = search_find_defer? DEFER : PANIC;
871 addr->message = string_sprintf("Expansion of \"%s\" (suffix for %s "
872 "transport) failed: %s", ob->message_suffix, tblock->name,
873 expand_string_message);
874 return FALSE;
875 }
876 if (!transport_write_block(fd_in, suffix, Ustrlen(suffix)))
877 goto END_WRITE;
878 }
879
880/* If local_smtp, write the terminating dot. */
881
882if (ob->use_bsmtp && !transport_write_string(fd_in, ".%s", eol))
883 goto END_WRITE;
884
885/* Flag all writing completed successfully. */
886
887written_ok = TRUE;
888
889/* Come here if there are errors during writing. */
890
891END_WRITE:
892
893/* OK, the writing is now all done. Close the pipe. */
894
895(void) close(fd_in);
896
897/* Handle errors during writing. For timeouts, set the timeout for waiting for
898the child process to 1 second. If the process at the far end of the pipe died
899without reading all of it, we expect an EPIPE error, which should be ignored.
900We used also to ignore WRITEINCOMPLETE but the writing function is now cleverer
901at handling OS where the death of a pipe doesn't give EPIPE immediately. See
2e2a30b4 902comments therein. */
0756eb3c
PH
903
904if (!written_ok)
905 {
906 if (errno == ETIMEDOUT)
2e2a30b4
PH
907 {
908 addr->message = string_sprintf("%stimeout while writing to pipe",
909 transport_filter_timed_out? "transport filter " : "");
910 addr->transport_return = ob->timeout_defer? DEFER : FAIL;
0756eb3c 911 timeout = 1;
2e2a30b4
PH
912 }
913 else if (errno == EPIPE)
0756eb3c 914 {
2e2a30b4 915 debug_printf("transport error EPIPE ignored\n");
0756eb3c
PH
916 }
917 else
918 {
8e669ac1 919 addr->transport_return = PANIC;
0756eb3c
PH
920 addr->basic_errno = errno;
921 if (errno == ERRNO_CHHEADER_FAIL)
922 addr->message =
923 string_sprintf("Failed to expand headers_add or headers_remove: %s",
924 expand_string_message);
925 else if (errno == ERRNO_FILTER_FAIL)
35af9f61
PH
926 addr->message = string_sprintf("Transport filter process failed (%d)%s",
927 addr->more_errno,
928 (addr->more_errno == EX_EXECFAILED)? ": unable to execute command" : "");
0756eb3c
PH
929 else if (errno == ERRNO_WRITEINCOMPLETE)
930 addr->message = string_sprintf("Failed repeatedly to write data");
931 else
932 addr->message = string_sprintf("Error %d", errno);
933 return FALSE;
934 }
935 }
936
937/* Wait for the child process to complete and take action if the returned
938status is nonzero. The timeout will be just 1 second if any of the writes
939above timed out. */
940
941if ((rc = child_close(pid, timeout)) != 0)
942 {
22c3b60b
PH
943 uschar *tmsg = (addr->message == NULL)? US"" :
944 string_sprintf(" (preceded by %s)", addr->message);
945
0756eb3c
PH
946 /* The process did not complete in time; kill its process group and fail
947 the delivery. It appears to be necessary to kill the output process too, as
948 otherwise it hangs on for some time if the actual pipe process is sleeping.
949 (At least, that's what I observed on Solaris 2.5.1.) Since we are failing
950 the delivery, that shouldn't cause any problem. */
951
952 if (rc == -256)
953 {
954 killpg(pid, SIGKILL);
955 kill(outpid, SIGKILL);
2e2a30b4 956 addr->transport_return = ob->timeout_defer? DEFER : FAIL;
22c3b60b 957 addr->message = string_sprintf("pipe delivery process timed out%s", tmsg);
0756eb3c
PH
958 }
959
960 /* Wait() failed. */
961
962 else if (rc == -257)
963 {
964 addr->transport_return = PANIC;
965 addr->message = string_sprintf("Wait() failed for child process of %s "
22c3b60b 966 "transport: %s%s", tblock->name, strerror(errno), tmsg);
0756eb3c
PH
967 }
968
52383f8f
NM
969 /* Since the transport_filter timed out we assume it has sent the child process
970 a malformed or incomplete data stream. Kill off the child process
971 and prevent checking its exit status as it will has probably exited in error.
972 This prevents the transport_filter timeout message from getting overwritten
973 by the exit error which is not the cause of the problem. */
974
975 else if (transport_filter_timed_out)
976 {
977 killpg(pid, SIGKILL);
978 kill(outpid, SIGKILL);
979 }
980
0756eb3c
PH
981 /* Either the process completed, but yielded a non-zero (necessarily
982 positive) status, or the process was terminated by a signal (rc will contain
983 the negation of the signal number). Treat killing by signal as failure unless
2fe76745
PP
984 status is being ignored. By default, the message is bounced back, unless
985 freeze_signal is set, in which case it is frozen instead. */
0756eb3c
PH
986
987 else if (rc < 0)
988 {
2fe76745
PP
989 if (ob->freeze_signal)
990 {
991 addr->transport_return = DEFER;
992 addr->special_action = SPECIAL_FREEZE;
993 addr->message = string_sprintf("Child process of %s transport (running "
994 "command \"%s\") was terminated by signal %d (%s)%s", tblock->name, cmd,
995 -rc, os_strsignal(-rc), tmsg);
996 }
997 else if (!ob->ignore_status)
0756eb3c
PH
998 {
999 addr->transport_return = FAIL;
1000 addr->message = string_sprintf("Child process of %s transport (running "
22c3b60b
PH
1001 "command \"%s\") was terminated by signal %d (%s)%s", tblock->name, cmd,
1002 -rc, os_strsignal(-rc), tmsg);
0756eb3c
PH
1003 }
1004 }
1005
1006 /* For positive values (process terminated with non-zero status), we need a
1007 status code to request deferral. A number of systems contain the following
1008 line in sysexits.h:
1009
1010 #define EX_TEMPFAIL 75
1011
1012 with the description
1013
1014 EX_TEMPFAIL -- temporary failure, indicating something that
1015 is not really an error. In sendmail, this means
1016 that a mailer (e.g.) could not create a connection,
1017 and the request should be reattempted later.
1018
1019 Based on this, we use exit code EX_TEMPFAIL as a default to mean "defer" when
1020 not ignoring the returned status. However, there is now an option that
1021 contains a list of temporary codes, with TEMPFAIL and CANTCREAT as defaults.
1022
1023 Another case that needs special treatment is if execve() failed (typically
1024 the command that was given is a non-existent path). By default this is
1025 treated as just another failure, but if freeze_exec_fail is set, the reaction
1026 is to freeze the message rather than bounce the address. Exim used to signal
1027 this failure with EX_UNAVAILABLE, which is definined in many systems as
1028
1029 #define EX_UNAVAILABLE 69
1030
1031 with the description
1032
1033 EX_UNAVAILABLE -- A service is unavailable. This can occur
1034 if a support program or file does not exist. This
1035 can also be used as a catchall message when something
1036 you wanted to do doesn't work, but you don't know why.
1037
1038 However, this can be confused with a command that actually returns 69 because
1039 something *it* wanted is unavailable. At release 4.21, Exim was changed to
1040 use return code 127 instead, because this is what the shell returns when it
1041 is unable to exec a command. We define it as EX_EXECFAILED, and use it in
1042 child.c to signal execve() failure and other unexpected failures such as
1043 setuid() not working - though that won't be the case here because we aren't
1044 changing uid. */
1045
1046 else
1047 {
1048 /* Always handle execve() failure specially if requested to */
1049
1050 if (ob->freeze_exec_fail && (rc == EX_EXECFAILED))
1051 {
1052 addr->transport_return = DEFER;
1053 addr->special_action = SPECIAL_FREEZE;
22c3b60b
PH
1054 addr->message = string_sprintf("pipe process failed to exec \"%s\"%s",
1055 cmd, tmsg);
0756eb3c
PH
1056 }
1057
1058 /* Otherwise take action only if not ignoring status */
1059
1060 else if (!ob->ignore_status)
1061 {
1062 uschar *ss;
1063 int size, ptr, i;
1064
1065 /* If temp_errors is "*" all codes are temporary. Initializion checks
1066 that it's either "*" or a list of numbers. If not "*", scan the list of
1067 temporary failure codes; if any match, the result is DEFER. */
1068
1069 if (ob->temp_errors[0] == '*')
1070 addr->transport_return = DEFER;
1071
1072 else
1073 {
bfe645c1 1074 const uschar *s = ob->temp_errors;
0756eb3c 1075 uschar *p;
0756eb3c
PH
1076 int sep = 0;
1077
1078 addr->transport_return = FAIL;
a94bdef3 1079 while ((p = string_nextinlist(&s,&sep,NULL,0)))
0756eb3c 1080 if (rc == Uatoi(p)) { addr->transport_return = DEFER; break; }
0756eb3c
PH
1081 }
1082
1083 /* Ensure the message contains the expanded command and arguments. This
1084 doesn't have to be brilliantly efficient - it is an error situation. */
1085
1086 addr->message = string_sprintf("Child process of %s transport returned "
1087 "%d", tblock->name, rc);
1088
1089 ptr = Ustrlen(addr->message);
1090 size = ptr + 1;
1091
1092 /* If the return code is > 128, it often means that a shell command
1093 was terminated by a signal. */
1094
1095 ss = (rc > 128)?
1096 string_sprintf("(could mean shell command ended by signal %d (%s))",
1097 rc-128, os_strsignal(rc-128)) :
1098 US os_strexit(rc);
1099
1100 if (*ss != 0)
1101 {
4fab92fb
HSHR
1102 addr->message = string_catn(addr->message, &size, &ptr, US" ", 1);
1103 addr->message = string_cat (addr->message, &size, &ptr, ss);
0756eb3c
PH
1104 }
1105
1106 /* Now add the command and arguments */
1107
4fab92fb 1108 addr->message = string_catn(addr->message, &size, &ptr,
0756eb3c
PH
1109 US" from command:", 14);
1110
1111 for (i = 0; i < sizeof(argv)/sizeof(int *) && argv[i] != NULL; i++)
1112 {
1113 BOOL quote = FALSE;
4fab92fb 1114 addr->message = string_catn(addr->message, &size, &ptr, US" ", 1);
0756eb3c
PH
1115 if (Ustrpbrk(argv[i], " \t") != NULL)
1116 {
1117 quote = TRUE;
4fab92fb 1118 addr->message = string_catn(addr->message, &size, &ptr, US"\"", 1);
0756eb3c 1119 }
4fab92fb 1120 addr->message = string_cat(addr->message, &size, &ptr, argv[i]);
0756eb3c 1121 if (quote)
4fab92fb 1122 addr->message = string_catn(addr->message, &size, &ptr, US"\"", 1);
0756eb3c 1123 }
22c3b60b
PH
1124
1125 /* Add previous filter timeout message, if present. */
1126
4fab92fb
HSHR
1127 if (*tmsg)
1128 addr->message = string_cat(addr->message, &size, &ptr, tmsg);
22c3b60b 1129
0756eb3c
PH
1130 addr->message[ptr] = 0; /* Ensure concatenated string terminated */
1131 }
1132 }
1133 }
1134
1135/* Ensure all subprocesses (in particular, the output handling process)
1136are complete before we pass this point. */
1137
1138while (wait(&rc) >= 0);
1139
1140DEBUG(D_transport) debug_printf("%s transport yielded %d\n", tblock->name,
1141 addr->transport_return);
1142
1143/* If there has been a problem, the message in addr->message contains details
1144of the pipe command. We don't want to expose these to the world, so we set up
1145something bland to return to the sender. */
1146
1147if (addr->transport_return != OK)
1148 addr->user_message = US"local delivery failed";
1149
1150return FALSE;
1151}
1152
1153/* End of transport/pipe.c */