Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
3386088d | 5 | /* Copyright (c) University of Cambridge 1995 - 2015 */ |
059ec3d9 PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
8 | ||
9 | #include "exim.h" | |
10 | ||
11 | static void (*oldsignal)(int); | |
12 | ||
8ac90765 JH |
13 | #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS) |
14 | static uschar tls_requiretls_copy = 0; | |
15 | #endif | |
16 | ||
059ec3d9 PH |
17 | |
18 | /************************************************* | |
19 | * Ensure an fd has a given value * | |
20 | *************************************************/ | |
21 | ||
22 | /* This function is called when we want to ensure that a certain fd has a | |
23 | specific value (one of 0, 1, 2). If it hasn't got it already, close the value | |
24 | we want, duplicate the fd, then close the old one. | |
25 | ||
26 | Arguments: | |
27 | oldfd original fd | |
28 | newfd the fd we want | |
29 | ||
30 | Returns: nothing | |
31 | */ | |
32 | ||
33 | static void | |
34 | force_fd(int oldfd, int newfd) | |
35 | { | |
36 | if (oldfd == newfd) return; | |
f1e894f3 PH |
37 | (void)close(newfd); |
38 | (void)dup2(oldfd, newfd); | |
39 | (void)close(oldfd); | |
059ec3d9 PH |
40 | } |
41 | ||
42 | ||
e7726cbf | 43 | #ifndef STAND_ALONE |
059ec3d9 PH |
44 | /************************************************* |
45 | * Build argv list and optionally re-exec Exim * | |
46 | *************************************************/ | |
47 | ||
48 | /* This function is called when Exim wants to re-exec (overlay) itself in the | |
49 | current process. This is different to child_open_exim(), which runs another | |
50 | Exim process in parallel (but it then calls this function). The function's | |
51 | basic job is to build the argv list according to the values of current options | |
52 | settings. There is a basic list that all calls require, and an additional list | |
53 | that some do not require. Further additions can be given as additional | |
54 | arguments. An option specifies whether the exec() is actually to happen, and if | |
55 | so, what is to be done if it fails. | |
56 | ||
57 | Arguments: | |
58 | exec_type CEE_RETURN_ARGV => don't exec; return the argv list | |
59 | CEE_EXEC_EXIT => just exit() on exec failure | |
60 | CEE_EXEC_PANIC => panic-die on exec failure | |
61 | kill_v if TRUE, don't pass on the D_v flag | |
62 | pcount if not NULL, points to extra size of argv required, and if | |
63 | CEE_RETURN_ARGV is specified, it is updated to give the | |
64 | number of slots used | |
65 | minimal TRUE if only minimal argv is required | |
66 | acount number of additional arguments | |
67 | ... further values to add to argv | |
68 | ||
69 | Returns: if CEE_RETURN_ARGV is given, returns a pointer to argv; | |
70 | otherwise, does not return | |
71 | */ | |
72 | ||
73 | uschar ** | |
74 | child_exec_exim(int exec_type, BOOL kill_v, int *pcount, BOOL minimal, | |
75 | int acount, ...) | |
76 | { | |
77 | int first_special = -1; | |
78 | int n = 0; | |
e37f8a84 | 79 | int extra = pcount ? *pcount : 0; |
8ac90765 JH |
80 | uschar **argv; |
81 | ||
82 | #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS) | |
83 | if (tls_requiretls) extra++; | |
84 | #endif | |
85 | ||
86 | argv = store_get((extra + acount + MAX_CLMACROS + 18) * sizeof(char *)); | |
059ec3d9 PH |
87 | |
88 | /* In all case, the list starts out with the path, any macros, and a changed | |
89 | config file. */ | |
90 | ||
91 | argv[n++] = exim_path; | |
92 | if (clmacro_count > 0) | |
93 | { | |
94 | memcpy(argv + n, clmacros, clmacro_count * sizeof(uschar *)); | |
95 | n += clmacro_count; | |
96 | } | |
8768d548 | 97 | if (f.config_changed) |
059ec3d9 PH |
98 | { |
99 | argv[n++] = US"-C"; | |
100 | argv[n++] = config_main_filename; | |
101 | } | |
102 | ||
103 | /* These values are added only for non-minimal cases. If debug_selector is | |
104 | precisely D_v, we have to assume this was started by a non-admin user, and | |
105 | we suppress the flag when requested. (This happens when passing on an SMTP | |
106 | connection, and after ETRN.) If there's more debugging going on, an admin user | |
107 | was involved, so we do pass it on. */ | |
108 | ||
109 | if (!minimal) | |
110 | { | |
111 | if (debug_selector == D_v) | |
112 | { | |
113 | if (!kill_v) argv[n++] = US"-v"; | |
114 | } | |
115 | else | |
116 | { | |
117 | if (debug_selector != 0) | |
118 | argv[n++] = string_sprintf("-d=0x%x", debug_selector); | |
119 | } | |
8768d548 JH |
120 | if (f.dont_deliver) argv[n++] = US"-N"; |
121 | if (f.queue_smtp) argv[n++] = US"-odqs"; | |
122 | if (f.synchronous_delivery) argv[n++] = US"-odi"; | |
059ec3d9 PH |
123 | if (connection_max_messages >= 0) |
124 | argv[n++] = string_sprintf("-oB%d", connection_max_messages); | |
e37f8a84 JH |
125 | if (*queue_name) |
126 | { | |
127 | argv[n++] = US"-MCG"; | |
128 | argv[n++] = queue_name; | |
129 | } | |
059ec3d9 PH |
130 | } |
131 | ||
8ac90765 JH |
132 | #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS) |
133 | if (tls_requiretls_copy & REQUIRETLS_MSG) | |
134 | argv[n++] = US"-MS"; | |
135 | #endif | |
136 | ||
059ec3d9 PH |
137 | /* Now add in any others that are in the call. Remember which they were, |
138 | for more helpful diagnosis on failure. */ | |
139 | ||
140 | if (acount > 0) | |
141 | { | |
142 | va_list ap; | |
143 | va_start(ap, acount); | |
144 | first_special = n; | |
145 | while (acount-- > 0) | |
146 | argv[n++] = va_arg(ap, uschar *); | |
147 | va_end(ap); | |
148 | } | |
149 | ||
150 | /* Terminate the list, and return it, if that is what is wanted. */ | |
151 | ||
152 | argv[n] = NULL; | |
153 | if (exec_type == CEE_RETURN_ARGV) | |
154 | { | |
155 | if (pcount != NULL) *pcount = n; | |
156 | return argv; | |
157 | } | |
158 | ||
159 | /* Otherwise, do the exec() here, and handle the consequences of an unexpected | |
160 | failure. We know that there will always be at least one extra option in the | |
161 | call when exec() is done here, so it can be used to add to the panic data. */ | |
162 | ||
55414b25 | 163 | DEBUG(D_exec) debug_print_argv(CUSS argv); |
059ec3d9 PH |
164 | exim_nullstd(); /* Make sure std{in,out,err} exist */ |
165 | execv(CS argv[0], (char *const *)argv); | |
166 | ||
167 | log_write(0, | |
168 | LOG_MAIN | ((exec_type == CEE_EXEC_EXIT)? LOG_PANIC : LOG_PANIC_DIE), | |
169 | "re-exec of exim (%s) with %s failed: %s", exim_path, argv[first_special], | |
170 | strerror(errno)); | |
171 | ||
172 | /* Get here if exec_type == CEE_EXEC_EXIT. | |
173 | Note: this must be _exit(), not exit(). */ | |
174 | ||
175 | _exit(EX_EXECFAILED); | |
176 | ||
177 | return NULL; /* To keep compilers happy */ | |
178 | } | |
179 | ||
180 | ||
181 | ||
182 | ||
183 | /************************************************* | |
184 | * Create a child Exim process * | |
185 | *************************************************/ | |
186 | ||
187 | /* This function is called when Exim wants to run a parallel instance of itself | |
188 | in order to inject a message via the standard input. The function creates a | |
189 | child process and runs Exim in it. It sets up a pipe to the standard input of | |
190 | the new process, and returns that to the caller via fdptr. The function returns | |
191 | the pid of the new process, or -1 if things go wrong. If debug_fd is | |
192 | non-negative, it is passed as stderr. | |
193 | ||
5977a0b3 PH |
194 | This interface is now a just wrapper for the more complicated function |
195 | child_open_exim2(), which has additional arguments. The wrapper must continue | |
196 | to exist, even if all calls from within Exim are changed, because it is | |
197 | documented for use from local_scan(). | |
198 | ||
059ec3d9 PH |
199 | Argument: fdptr pointer to int for the stdin fd |
200 | Returns: pid of the created process or -1 if anything has gone wrong | |
201 | */ | |
202 | ||
203 | pid_t | |
204 | child_open_exim(int *fdptr) | |
205 | { | |
5977a0b3 PH |
206 | return child_open_exim2(fdptr, US"<>", bounce_sender_authentication); |
207 | } | |
208 | ||
209 | ||
210 | /* This is a more complicated function for creating a child Exim process, with | |
211 | more arguments. | |
212 | ||
213 | Arguments: | |
214 | fdptr pointer to int for the stdin fd | |
215 | sender for a sender address (data for -f) | |
216 | sender_authentication authenticated sender address or NULL | |
217 | ||
218 | Returns: pid of the created process or -1 if anything has gone wrong | |
219 | */ | |
220 | ||
221 | pid_t | |
222 | child_open_exim2(int *fdptr, uschar *sender, uschar *sender_authentication) | |
223 | { | |
059ec3d9 PH |
224 | int pfd[2]; |
225 | int save_errno; | |
226 | pid_t pid; | |
227 | ||
228 | /* Create the pipe and fork the process. Ensure that SIGCHLD is set to | |
229 | SIG_DFL before forking, so that the child process can be waited for. We | |
230 | sometimes get here with it set otherwise. Save the old state for resetting | |
231 | on the wait. */ | |
232 | ||
233 | if (pipe(pfd) != 0) return (pid_t)(-1); | |
234 | oldsignal = signal(SIGCHLD, SIG_DFL); | |
235 | pid = fork(); | |
236 | ||
237 | /* Child process: make the reading end of the pipe into the standard input and | |
238 | close the writing end. If debugging, pass debug_fd as stderr. Then re-exec | |
4c04137d | 239 | Exim with appropriate options. In the test harness, use -odi unless queue_only |
75e0e026 PH |
240 | is set, so that the bounce is fully delivered before returning. Failure is |
241 | signalled with EX_EXECFAILED (specified by CEE_EXEC_EXIT), but this shouldn't | |
242 | occur. */ | |
059ec3d9 PH |
243 | |
244 | if (pid == 0) | |
245 | { | |
8ac90765 JH |
246 | #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS) |
247 | tls_requiretls_copy = tls_requiretls; | |
248 | #endif | |
059ec3d9 | 249 | force_fd(pfd[pipe_read], 0); |
f1e894f3 | 250 | (void)close(pfd[pipe_write]); |
059ec3d9 | 251 | if (debug_fd > 0) force_fd(debug_fd, 2); |
8768d548 | 252 | if (f.running_in_test_harness && !queue_only) |
75e0e026 PH |
253 | { |
254 | if (sender_authentication != NULL) | |
255 | child_exec_exim(CEE_EXEC_EXIT, FALSE, NULL, FALSE, 9, | |
256 | US "-odi", US"-t", US"-oem", US"-oi", US"-f", sender, US"-oMas", | |
257 | sender_authentication, message_id_option); | |
258 | else | |
259 | child_exec_exim(CEE_EXEC_EXIT, FALSE, NULL, FALSE, 7, | |
260 | US "-odi", US"-t", US"-oem", US"-oi", US"-f", sender, | |
261 | message_id_option); | |
262 | /* Control does not return here. */ | |
263 | } | |
264 | else /* Not test harness */ | |
265 | { | |
266 | if (sender_authentication != NULL) | |
267 | child_exec_exim(CEE_EXEC_EXIT, FALSE, NULL, FALSE, 8, | |
268 | US"-t", US"-oem", US"-oi", US"-f", sender, US"-oMas", | |
269 | sender_authentication, message_id_option); | |
270 | else | |
271 | child_exec_exim(CEE_EXEC_EXIT, FALSE, NULL, FALSE, 6, | |
272 | US"-t", US"-oem", US"-oi", US"-f", sender, message_id_option); | |
273 | /* Control does not return here. */ | |
274 | } | |
059ec3d9 PH |
275 | } |
276 | ||
277 | /* Parent process. Save fork() errno and close the reading end of the stdin | |
278 | pipe. */ | |
279 | ||
280 | save_errno = errno; | |
f1e894f3 | 281 | (void)close(pfd[pipe_read]); |
059ec3d9 PH |
282 | |
283 | /* Fork succeeded */ | |
284 | ||
285 | if (pid > 0) | |
286 | { | |
287 | *fdptr = pfd[pipe_write]; /* return writing end of stdin pipe */ | |
288 | return pid; /* and pid of new process */ | |
289 | } | |
290 | ||
291 | /* Fork failed */ | |
292 | ||
f1e894f3 | 293 | (void)close(pfd[pipe_write]); |
059ec3d9 PH |
294 | errno = save_errno; |
295 | return (pid_t)(-1); | |
296 | } | |
75e0e026 | 297 | #endif /* STAND_ALONE */ |
059ec3d9 PH |
298 | |
299 | ||
300 | ||
301 | /************************************************* | |
302 | * Create a non-Exim child process * | |
303 | *************************************************/ | |
304 | ||
305 | /* This function creates a child process and runs the given command in it. It | |
306 | sets up pipes to the standard input and output of the new process, and returns | |
307 | them to the caller. The standard error is cloned to the output. If there are | |
308 | any file descriptors "in the way" in the new process, they are closed. A new | |
309 | umask is supplied for the process, and an optional new uid and gid are also | |
310 | available. These are used by the queryprogram router to set an unprivileged id. | |
b668c215 PH |
311 | SIGUSR1 is always disabled in the new process, as it is not going to be running |
312 | Exim (the function child_open_exim() is provided for that). This function | |
313 | returns the pid of the new process, or -1 if things go wrong. | |
059ec3d9 PH |
314 | |
315 | Arguments: | |
316 | argv the argv for exec in the new process | |
317 | envp the envp for exec in the new process | |
318 | newumask umask to set in the new process | |
319 | newuid point to uid for the new process or NULL for no change | |
320 | newgid point to gid for the new process or NULL for no change | |
321 | infdptr pointer to int into which the fd of the stdin of the new process | |
322 | is placed | |
323 | outfdptr pointer to int into which the fd of the stdout/stderr of the new | |
324 | process is placed | |
325 | wd if not NULL, a path to be handed to chdir() in the new process | |
326 | make_leader if TRUE, make the new process a process group leader | |
8e669ac1 | 327 | |
059ec3d9 PH |
328 | Returns: the pid of the created process or -1 if anything has gone wrong |
329 | */ | |
330 | ||
331 | pid_t | |
55414b25 JH |
332 | child_open_uid(const uschar **argv, const uschar **envp, int newumask, |
333 | uid_t *newuid, gid_t *newgid, int *infdptr, int *outfdptr, uschar *wd, | |
334 | BOOL make_leader) | |
059ec3d9 PH |
335 | { |
336 | int save_errno; | |
337 | int inpfd[2], outpfd[2]; | |
338 | pid_t pid; | |
339 | ||
340 | /* Create the pipes. */ | |
341 | ||
342 | if (pipe(inpfd) != 0) return (pid_t)(-1); | |
343 | if (pipe(outpfd) != 0) | |
344 | { | |
f1e894f3 PH |
345 | (void)close(inpfd[pipe_read]); |
346 | (void)close(inpfd[pipe_write]); | |
059ec3d9 PH |
347 | return (pid_t)(-1); |
348 | } | |
349 | ||
350 | /* Fork the process. Ensure that SIGCHLD is set to SIG_DFL before forking, so | |
351 | that the child process can be waited for. We sometimes get here with it set | |
352 | otherwise. Save the old state for resetting on the wait. */ | |
353 | ||
354 | oldsignal = signal(SIGCHLD, SIG_DFL); | |
355 | pid = fork(); | |
356 | ||
59e82a2a PH |
357 | /* Handle the child process. First, set the required environment. We must do |
358 | this before messing with the pipes, in order to be able to write debugging | |
359 | output when things go wrong. */ | |
059ec3d9 PH |
360 | |
361 | if (pid == 0) | |
362 | { | |
59e82a2a | 363 | signal(SIGUSR1, SIG_IGN); |
605021fc | 364 | signal(SIGPIPE, SIG_DFL); |
59e82a2a PH |
365 | |
366 | if (newgid != NULL && setgid(*newgid) < 0) | |
367 | { | |
368 | DEBUG(D_any) debug_printf("failed to set gid=%ld in subprocess: %s\n", | |
369 | (long int)(*newgid), strerror(errno)); | |
370 | goto CHILD_FAILED; | |
371 | } | |
372 | ||
373 | if (newuid != NULL && setuid(*newuid) < 0) | |
374 | { | |
375 | DEBUG(D_any) debug_printf("failed to set uid=%ld in subprocess: %s\n", | |
376 | (long int)(*newuid), strerror(errno)); | |
377 | goto CHILD_FAILED; | |
378 | } | |
379 | ||
380 | (void)umask(newumask); | |
381 | ||
382 | if (wd != NULL && Uchdir(wd) < 0) | |
383 | { | |
384 | DEBUG(D_any) debug_printf("failed to chdir to %s: %s\n", wd, | |
385 | strerror(errno)); | |
386 | goto CHILD_FAILED; | |
387 | } | |
388 | ||
389 | /* Becomes a process group leader if requested, and then organize the pipes. | |
390 | Any unexpected failure is signalled with EX_EXECFAILED; these are all "should | |
391 | never occur" failures, except for exec failing because the command doesn't | |
392 | exist. */ | |
393 | ||
394 | if (make_leader && setpgid(0,0) < 0) | |
395 | { | |
396 | DEBUG(D_any) debug_printf("failed to set group leader in subprocess: %s\n", | |
397 | strerror(errno)); | |
398 | goto CHILD_FAILED; | |
399 | } | |
059ec3d9 | 400 | |
f1e894f3 | 401 | (void)close(inpfd[pipe_write]); |
059ec3d9 PH |
402 | force_fd(inpfd[pipe_read], 0); |
403 | ||
f1e894f3 | 404 | (void)close(outpfd[pipe_read]); |
059ec3d9 PH |
405 | force_fd(outpfd[pipe_write], 1); |
406 | ||
f1e894f3 PH |
407 | (void)close(2); |
408 | (void)dup2(1, 2); | |
059ec3d9 | 409 | |
059ec3d9 PH |
410 | /* Now do the exec */ |
411 | ||
412 | if (envp == NULL) execv(CS argv[0], (char *const *)argv); | |
55414b25 | 413 | else execve(CS argv[0], (char *const *)argv, (char *const *)envp); |
059ec3d9 PH |
414 | |
415 | /* Failed to execv. Signal this failure using EX_EXECFAILED. We are | |
416 | losing the actual errno we got back, because there is no way to return | |
59e82a2a | 417 | this information. */ |
059ec3d9 PH |
418 | |
419 | CHILD_FAILED: | |
420 | _exit(EX_EXECFAILED); /* Note: must be _exit(), NOT exit() */ | |
421 | } | |
422 | ||
423 | /* Parent process. Save any fork failure code, and close the reading end of the | |
424 | stdin pipe, and the writing end of the stdout pipe. */ | |
425 | ||
426 | save_errno = errno; | |
f1e894f3 PH |
427 | (void)close(inpfd[pipe_read]); |
428 | (void)close(outpfd[pipe_write]); | |
059ec3d9 PH |
429 | |
430 | /* Fork succeeded; return the input/output pipes and the pid */ | |
431 | ||
432 | if (pid > 0) | |
433 | { | |
434 | *infdptr = inpfd[pipe_write]; | |
435 | *outfdptr = outpfd[pipe_read]; | |
436 | return pid; | |
437 | } | |
438 | ||
439 | /* Fork failed; reset fork errno before returning */ | |
440 | ||
f1e894f3 PH |
441 | (void)close(inpfd[pipe_write]); |
442 | (void)close(outpfd[pipe_read]); | |
059ec3d9 PH |
443 | errno = save_errno; |
444 | return (pid_t)(-1); | |
445 | } | |
446 | ||
447 | ||
448 | ||
449 | ||
450 | /************************************************* | |
451 | * Create child process without uid change * | |
452 | *************************************************/ | |
453 | ||
454 | /* This function is a wrapper for child_open_uid() that doesn't have the uid, | |
b668c215 PH |
455 | gid and working directory changing arguments. The function is provided so as to |
456 | have a clean interface for use from local_scan(), but also saves writing NULL | |
457 | arguments several calls that would otherwise use child_open_uid(). | |
059ec3d9 PH |
458 | |
459 | Arguments: | |
460 | argv the argv for exec in the new process | |
461 | envp the envp for exec in the new process | |
462 | newumask umask to set in the new process | |
463 | infdptr pointer to int into which the fd of the stdin of the new process | |
464 | is placed | |
465 | outfdptr pointer to int into which the fd of the stdout/stderr of the new | |
466 | process is placed | |
467 | make_leader if TRUE, make the new process a process group leader | |
468 | ||
469 | Returns: the pid of the created process or -1 if anything has gone wrong | |
470 | */ | |
471 | ||
472 | pid_t | |
473 | child_open(uschar **argv, uschar **envp, int newumask, int *infdptr, | |
474 | int *outfdptr, BOOL make_leader) | |
475 | { | |
55414b25 JH |
476 | return child_open_uid(CUSS argv, CUSS envp, newumask, NULL, NULL, |
477 | infdptr, outfdptr, NULL, make_leader); | |
059ec3d9 PH |
478 | } |
479 | ||
480 | ||
481 | ||
482 | ||
483 | /************************************************* | |
484 | * Close down child process * | |
485 | *************************************************/ | |
486 | ||
487 | /* Wait for the given process to finish, with optional timeout. | |
488 | ||
489 | Arguments | |
490 | pid: the pid to wait for | |
491 | timeout: maximum time to wait; 0 means for as long as it takes | |
492 | ||
493 | Returns: >= 0 process terminated by exiting; value is process | |
494 | ending status; if an execve() failed, the value | |
495 | is typically 127 (defined as EX_EXECFAILED) | |
496 | < 0 & > -256 process was terminated by a signal; value is the | |
497 | negation of the signal number | |
498 | -256 timed out | |
499 | -257 other error in wait(); errno still set | |
500 | */ | |
501 | ||
502 | int | |
503 | child_close(pid_t pid, int timeout) | |
504 | { | |
505 | int yield; | |
506 | ||
507 | if (timeout > 0) | |
508 | { | |
509 | sigalrm_seen = FALSE; | |
c2a1bba0 | 510 | ALARM(timeout); |
059ec3d9 PH |
511 | } |
512 | ||
513 | for(;;) | |
514 | { | |
515 | int status; | |
516 | pid_t rc = waitpid(pid, &status, 0); | |
517 | if (rc == pid) | |
518 | { | |
519 | int lowbyte = status & 255; | |
d7625a4d | 520 | yield = lowbyte == 0 ? (status >> 8) & 255 : -lowbyte; |
059ec3d9 PH |
521 | break; |
522 | } | |
523 | if (rc < 0) | |
524 | { | |
d7625a4d JH |
525 | /* This "shouldn't happen" test does happen on MacOS: for some reason |
526 | I do not understand we seems to get an alarm signal despite not having | |
527 | an active alarm set. There seems to be only one, so just go round again. */ | |
528 | ||
529 | if (errno == EINTR && sigalrm_seen && timeout <= 0) continue; | |
530 | ||
531 | yield = (errno == EINTR && sigalrm_seen) ? -256 : -257; | |
059ec3d9 PH |
532 | break; |
533 | } | |
534 | } | |
535 | ||
c2a1bba0 | 536 | if (timeout > 0) ALARM_CLR(0); |
059ec3d9 PH |
537 | |
538 | signal(SIGCHLD, oldsignal); /* restore */ | |
539 | return yield; | |
540 | } | |
541 | ||
542 | /* End of child.c */ |