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 | ||
13 | ||
14 | /************************************************* | |
15 | * Ensure an fd has a given value * | |
16 | *************************************************/ | |
17 | ||
18 | /* This function is called when we want to ensure that a certain fd has a | |
19 | specific value (one of 0, 1, 2). If it hasn't got it already, close the value | |
20 | we want, duplicate the fd, then close the old one. | |
21 | ||
22 | Arguments: | |
23 | oldfd original fd | |
24 | newfd the fd we want | |
25 | ||
26 | Returns: nothing | |
27 | */ | |
28 | ||
29 | static void | |
30 | force_fd(int oldfd, int newfd) | |
31 | { | |
32 | if (oldfd == newfd) return; | |
f1e894f3 PH |
33 | (void)close(newfd); |
34 | (void)dup2(oldfd, newfd); | |
35 | (void)close(oldfd); | |
059ec3d9 PH |
36 | } |
37 | ||
38 | ||
e7726cbf | 39 | #ifndef STAND_ALONE |
059ec3d9 PH |
40 | /************************************************* |
41 | * Build argv list and optionally re-exec Exim * | |
42 | *************************************************/ | |
43 | ||
44 | /* This function is called when Exim wants to re-exec (overlay) itself in the | |
45 | current process. This is different to child_open_exim(), which runs another | |
46 | Exim process in parallel (but it then calls this function). The function's | |
47 | basic job is to build the argv list according to the values of current options | |
48 | settings. There is a basic list that all calls require, and an additional list | |
49 | that some do not require. Further additions can be given as additional | |
50 | arguments. An option specifies whether the exec() is actually to happen, and if | |
51 | so, what is to be done if it fails. | |
52 | ||
53 | Arguments: | |
54 | exec_type CEE_RETURN_ARGV => don't exec; return the argv list | |
55 | CEE_EXEC_EXIT => just exit() on exec failure | |
56 | CEE_EXEC_PANIC => panic-die on exec failure | |
57 | kill_v if TRUE, don't pass on the D_v flag | |
58 | pcount if not NULL, points to extra size of argv required, and if | |
59 | CEE_RETURN_ARGV is specified, it is updated to give the | |
60 | number of slots used | |
61 | minimal TRUE if only minimal argv is required | |
62 | acount number of additional arguments | |
63 | ... further values to add to argv | |
64 | ||
65 | Returns: if CEE_RETURN_ARGV is given, returns a pointer to argv; | |
66 | otherwise, does not return | |
67 | */ | |
68 | ||
69 | uschar ** | |
70 | child_exec_exim(int exec_type, BOOL kill_v, int *pcount, BOOL minimal, | |
71 | int acount, ...) | |
72 | { | |
73 | int first_special = -1; | |
74 | int n = 0; | |
e37f8a84 | 75 | int extra = pcount ? *pcount : 0; |
8ac90765 JH |
76 | uschar **argv; |
77 | ||
ff966302 | 78 | argv = store_get((extra + acount + MAX_CLMACROS + 19) * sizeof(char *), FALSE); |
059ec3d9 PH |
79 | |
80 | /* In all case, the list starts out with the path, any macros, and a changed | |
81 | config file. */ | |
82 | ||
83 | argv[n++] = exim_path; | |
84 | if (clmacro_count > 0) | |
85 | { | |
86 | memcpy(argv + n, clmacros, clmacro_count * sizeof(uschar *)); | |
87 | n += clmacro_count; | |
88 | } | |
8768d548 | 89 | if (f.config_changed) |
059ec3d9 PH |
90 | { |
91 | argv[n++] = US"-C"; | |
92 | argv[n++] = config_main_filename; | |
93 | } | |
94 | ||
95 | /* These values are added only for non-minimal cases. If debug_selector is | |
96 | precisely D_v, we have to assume this was started by a non-admin user, and | |
97 | we suppress the flag when requested. (This happens when passing on an SMTP | |
98 | connection, and after ETRN.) If there's more debugging going on, an admin user | |
99 | was involved, so we do pass it on. */ | |
100 | ||
101 | if (!minimal) | |
102 | { | |
103 | if (debug_selector == D_v) | |
104 | { | |
105 | if (!kill_v) argv[n++] = US"-v"; | |
106 | } | |
107 | else | |
108 | { | |
109 | if (debug_selector != 0) | |
110 | argv[n++] = string_sprintf("-d=0x%x", debug_selector); | |
111 | } | |
ff966302 | 112 | if (!f.testsuite_delays) argv[n++] = US"-odd"; |
8768d548 JH |
113 | if (f.dont_deliver) argv[n++] = US"-N"; |
114 | if (f.queue_smtp) argv[n++] = US"-odqs"; | |
115 | if (f.synchronous_delivery) argv[n++] = US"-odi"; | |
059ec3d9 PH |
116 | if (connection_max_messages >= 0) |
117 | argv[n++] = string_sprintf("-oB%d", connection_max_messages); | |
e37f8a84 JH |
118 | if (*queue_name) |
119 | { | |
120 | argv[n++] = US"-MCG"; | |
121 | argv[n++] = queue_name; | |
122 | } | |
059ec3d9 PH |
123 | } |
124 | ||
125 | /* Now add in any others that are in the call. Remember which they were, | |
126 | for more helpful diagnosis on failure. */ | |
127 | ||
128 | if (acount > 0) | |
129 | { | |
130 | va_list ap; | |
131 | va_start(ap, acount); | |
132 | first_special = n; | |
133 | while (acount-- > 0) | |
134 | argv[n++] = va_arg(ap, uschar *); | |
135 | va_end(ap); | |
136 | } | |
137 | ||
138 | /* Terminate the list, and return it, if that is what is wanted. */ | |
139 | ||
140 | argv[n] = NULL; | |
141 | if (exec_type == CEE_RETURN_ARGV) | |
142 | { | |
143 | if (pcount != NULL) *pcount = n; | |
144 | return argv; | |
145 | } | |
146 | ||
147 | /* Otherwise, do the exec() here, and handle the consequences of an unexpected | |
148 | failure. We know that there will always be at least one extra option in the | |
149 | call when exec() is done here, so it can be used to add to the panic data. */ | |
150 | ||
55414b25 | 151 | DEBUG(D_exec) debug_print_argv(CUSS argv); |
059ec3d9 PH |
152 | exim_nullstd(); /* Make sure std{in,out,err} exist */ |
153 | execv(CS argv[0], (char *const *)argv); | |
154 | ||
155 | log_write(0, | |
156 | LOG_MAIN | ((exec_type == CEE_EXEC_EXIT)? LOG_PANIC : LOG_PANIC_DIE), | |
157 | "re-exec of exim (%s) with %s failed: %s", exim_path, argv[first_special], | |
158 | strerror(errno)); | |
159 | ||
160 | /* Get here if exec_type == CEE_EXEC_EXIT. | |
161 | Note: this must be _exit(), not exit(). */ | |
162 | ||
163 | _exit(EX_EXECFAILED); | |
164 | ||
165 | return NULL; /* To keep compilers happy */ | |
166 | } | |
167 | ||
168 | ||
169 | ||
170 | ||
171 | /************************************************* | |
172 | * Create a child Exim process * | |
173 | *************************************************/ | |
174 | ||
175 | /* This function is called when Exim wants to run a parallel instance of itself | |
176 | in order to inject a message via the standard input. The function creates a | |
177 | child process and runs Exim in it. It sets up a pipe to the standard input of | |
178 | the new process, and returns that to the caller via fdptr. The function returns | |
179 | the pid of the new process, or -1 if things go wrong. If debug_fd is | |
180 | non-negative, it is passed as stderr. | |
181 | ||
5977a0b3 PH |
182 | This interface is now a just wrapper for the more complicated function |
183 | child_open_exim2(), which has additional arguments. The wrapper must continue | |
184 | to exist, even if all calls from within Exim are changed, because it is | |
185 | documented for use from local_scan(). | |
186 | ||
059ec3d9 | 187 | Argument: fdptr pointer to int for the stdin fd |
8e9fdd63 | 188 | purpose of the child process, for debug |
059ec3d9 PH |
189 | Returns: pid of the created process or -1 if anything has gone wrong |
190 | */ | |
191 | ||
192 | pid_t | |
8e9fdd63 | 193 | child_open_exim_function(int * fdptr, const uschar * purpose) |
059ec3d9 | 194 | { |
8e9fdd63 JH |
195 | return child_open_exim2_function(fdptr, US"<>", bounce_sender_authentication, |
196 | purpose); | |
5977a0b3 PH |
197 | } |
198 | ||
199 | ||
200 | /* This is a more complicated function for creating a child Exim process, with | |
201 | more arguments. | |
202 | ||
203 | Arguments: | |
204 | fdptr pointer to int for the stdin fd | |
205 | sender for a sender address (data for -f) | |
206 | sender_authentication authenticated sender address or NULL | |
8e9fdd63 | 207 | purpose of the child process, for debug |
5977a0b3 PH |
208 | |
209 | Returns: pid of the created process or -1 if anything has gone wrong | |
210 | */ | |
211 | ||
212 | pid_t | |
8e9fdd63 JH |
213 | child_open_exim2_function(int * fdptr, uschar * sender, |
214 | uschar * sender_authentication, const uschar * purpose) | |
5977a0b3 | 215 | { |
059ec3d9 PH |
216 | int pfd[2]; |
217 | int save_errno; | |
218 | pid_t pid; | |
219 | ||
220 | /* Create the pipe and fork the process. Ensure that SIGCHLD is set to | |
221 | SIG_DFL before forking, so that the child process can be waited for. We | |
222 | sometimes get here with it set otherwise. Save the old state for resetting | |
223 | on the wait. */ | |
224 | ||
225 | if (pipe(pfd) != 0) return (pid_t)(-1); | |
226 | oldsignal = signal(SIGCHLD, SIG_DFL); | |
8e9fdd63 | 227 | pid = exim_fork(purpose); |
059ec3d9 PH |
228 | |
229 | /* Child process: make the reading end of the pipe into the standard input and | |
230 | close the writing end. If debugging, pass debug_fd as stderr. Then re-exec | |
4c04137d | 231 | Exim with appropriate options. In the test harness, use -odi unless queue_only |
75e0e026 PH |
232 | is set, so that the bounce is fully delivered before returning. Failure is |
233 | signalled with EX_EXECFAILED (specified by CEE_EXEC_EXIT), but this shouldn't | |
234 | occur. */ | |
059ec3d9 PH |
235 | |
236 | if (pid == 0) | |
237 | { | |
238 | force_fd(pfd[pipe_read], 0); | |
f1e894f3 | 239 | (void)close(pfd[pipe_write]); |
059ec3d9 | 240 | if (debug_fd > 0) force_fd(debug_fd, 2); |
8768d548 | 241 | if (f.running_in_test_harness && !queue_only) |
75e0e026 PH |
242 | { |
243 | if (sender_authentication != NULL) | |
244 | child_exec_exim(CEE_EXEC_EXIT, FALSE, NULL, FALSE, 9, | |
245 | US "-odi", US"-t", US"-oem", US"-oi", US"-f", sender, US"-oMas", | |
246 | sender_authentication, message_id_option); | |
247 | else | |
248 | child_exec_exim(CEE_EXEC_EXIT, FALSE, NULL, FALSE, 7, | |
249 | US "-odi", US"-t", US"-oem", US"-oi", US"-f", sender, | |
250 | message_id_option); | |
251 | /* Control does not return here. */ | |
252 | } | |
253 | else /* Not test harness */ | |
254 | { | |
255 | if (sender_authentication != NULL) | |
256 | child_exec_exim(CEE_EXEC_EXIT, FALSE, NULL, FALSE, 8, | |
257 | US"-t", US"-oem", US"-oi", US"-f", sender, US"-oMas", | |
258 | sender_authentication, message_id_option); | |
259 | else | |
260 | child_exec_exim(CEE_EXEC_EXIT, FALSE, NULL, FALSE, 6, | |
261 | US"-t", US"-oem", US"-oi", US"-f", sender, message_id_option); | |
262 | /* Control does not return here. */ | |
263 | } | |
059ec3d9 PH |
264 | } |
265 | ||
266 | /* Parent process. Save fork() errno and close the reading end of the stdin | |
267 | pipe. */ | |
268 | ||
269 | save_errno = errno; | |
f1e894f3 | 270 | (void)close(pfd[pipe_read]); |
059ec3d9 PH |
271 | |
272 | /* Fork succeeded */ | |
273 | ||
274 | if (pid > 0) | |
275 | { | |
276 | *fdptr = pfd[pipe_write]; /* return writing end of stdin pipe */ | |
277 | return pid; /* and pid of new process */ | |
278 | } | |
279 | ||
280 | /* Fork failed */ | |
281 | ||
f1e894f3 | 282 | (void)close(pfd[pipe_write]); |
059ec3d9 PH |
283 | errno = save_errno; |
284 | return (pid_t)(-1); | |
285 | } | |
75e0e026 | 286 | #endif /* STAND_ALONE */ |
059ec3d9 PH |
287 | |
288 | ||
289 | ||
290 | /************************************************* | |
291 | * Create a non-Exim child process * | |
292 | *************************************************/ | |
293 | ||
294 | /* This function creates a child process and runs the given command in it. It | |
295 | sets up pipes to the standard input and output of the new process, and returns | |
296 | them to the caller. The standard error is cloned to the output. If there are | |
297 | any file descriptors "in the way" in the new process, they are closed. A new | |
298 | umask is supplied for the process, and an optional new uid and gid are also | |
299 | available. These are used by the queryprogram router to set an unprivileged id. | |
b668c215 PH |
300 | SIGUSR1 is always disabled in the new process, as it is not going to be running |
301 | Exim (the function child_open_exim() is provided for that). This function | |
302 | returns the pid of the new process, or -1 if things go wrong. | |
059ec3d9 PH |
303 | |
304 | Arguments: | |
305 | argv the argv for exec in the new process | |
306 | envp the envp for exec in the new process | |
307 | newumask umask to set in the new process | |
308 | newuid point to uid for the new process or NULL for no change | |
309 | newgid point to gid for the new process or NULL for no change | |
310 | infdptr pointer to int into which the fd of the stdin of the new process | |
311 | is placed | |
312 | outfdptr pointer to int into which the fd of the stdout/stderr of the new | |
313 | process is placed | |
314 | wd if not NULL, a path to be handed to chdir() in the new process | |
315 | make_leader if TRUE, make the new process a process group leader | |
8e669ac1 | 316 | |
059ec3d9 PH |
317 | Returns: the pid of the created process or -1 if anything has gone wrong |
318 | */ | |
319 | ||
320 | pid_t | |
55414b25 JH |
321 | child_open_uid(const uschar **argv, const uschar **envp, int newumask, |
322 | uid_t *newuid, gid_t *newgid, int *infdptr, int *outfdptr, uschar *wd, | |
323 | BOOL make_leader) | |
059ec3d9 PH |
324 | { |
325 | int save_errno; | |
326 | int inpfd[2], outpfd[2]; | |
327 | pid_t pid; | |
328 | ||
329 | /* Create the pipes. */ | |
330 | ||
331 | if (pipe(inpfd) != 0) return (pid_t)(-1); | |
332 | if (pipe(outpfd) != 0) | |
333 | { | |
f1e894f3 PH |
334 | (void)close(inpfd[pipe_read]); |
335 | (void)close(inpfd[pipe_write]); | |
059ec3d9 PH |
336 | return (pid_t)(-1); |
337 | } | |
338 | ||
339 | /* Fork the process. Ensure that SIGCHLD is set to SIG_DFL before forking, so | |
340 | that the child process can be waited for. We sometimes get here with it set | |
341 | otherwise. Save the old state for resetting on the wait. */ | |
342 | ||
343 | oldsignal = signal(SIGCHLD, SIG_DFL); | |
8e9fdd63 | 344 | pid = exim_fork(US"queryprogram"); /* queryprogram tpt is sole caller */ |
059ec3d9 | 345 | |
59e82a2a PH |
346 | /* Handle the child process. First, set the required environment. We must do |
347 | this before messing with the pipes, in order to be able to write debugging | |
348 | output when things go wrong. */ | |
059ec3d9 PH |
349 | |
350 | if (pid == 0) | |
351 | { | |
59e82a2a | 352 | signal(SIGUSR1, SIG_IGN); |
605021fc | 353 | signal(SIGPIPE, SIG_DFL); |
59e82a2a PH |
354 | |
355 | if (newgid != NULL && setgid(*newgid) < 0) | |
356 | { | |
357 | DEBUG(D_any) debug_printf("failed to set gid=%ld in subprocess: %s\n", | |
358 | (long int)(*newgid), strerror(errno)); | |
359 | goto CHILD_FAILED; | |
360 | } | |
361 | ||
362 | if (newuid != NULL && setuid(*newuid) < 0) | |
363 | { | |
364 | DEBUG(D_any) debug_printf("failed to set uid=%ld in subprocess: %s\n", | |
365 | (long int)(*newuid), strerror(errno)); | |
366 | goto CHILD_FAILED; | |
367 | } | |
368 | ||
369 | (void)umask(newumask); | |
370 | ||
371 | if (wd != NULL && Uchdir(wd) < 0) | |
372 | { | |
373 | DEBUG(D_any) debug_printf("failed to chdir to %s: %s\n", wd, | |
374 | strerror(errno)); | |
375 | goto CHILD_FAILED; | |
376 | } | |
377 | ||
378 | /* Becomes a process group leader if requested, and then organize the pipes. | |
379 | Any unexpected failure is signalled with EX_EXECFAILED; these are all "should | |
380 | never occur" failures, except for exec failing because the command doesn't | |
381 | exist. */ | |
382 | ||
383 | if (make_leader && setpgid(0,0) < 0) | |
384 | { | |
385 | DEBUG(D_any) debug_printf("failed to set group leader in subprocess: %s\n", | |
386 | strerror(errno)); | |
387 | goto CHILD_FAILED; | |
388 | } | |
059ec3d9 | 389 | |
f1e894f3 | 390 | (void)close(inpfd[pipe_write]); |
059ec3d9 PH |
391 | force_fd(inpfd[pipe_read], 0); |
392 | ||
f1e894f3 | 393 | (void)close(outpfd[pipe_read]); |
059ec3d9 PH |
394 | force_fd(outpfd[pipe_write], 1); |
395 | ||
f1e894f3 PH |
396 | (void)close(2); |
397 | (void)dup2(1, 2); | |
059ec3d9 | 398 | |
059ec3d9 PH |
399 | /* Now do the exec */ |
400 | ||
401 | if (envp == NULL) execv(CS argv[0], (char *const *)argv); | |
55414b25 | 402 | else execve(CS argv[0], (char *const *)argv, (char *const *)envp); |
059ec3d9 PH |
403 | |
404 | /* Failed to execv. Signal this failure using EX_EXECFAILED. We are | |
405 | losing the actual errno we got back, because there is no way to return | |
59e82a2a | 406 | this information. */ |
059ec3d9 PH |
407 | |
408 | CHILD_FAILED: | |
409 | _exit(EX_EXECFAILED); /* Note: must be _exit(), NOT exit() */ | |
410 | } | |
411 | ||
412 | /* Parent process. Save any fork failure code, and close the reading end of the | |
413 | stdin pipe, and the writing end of the stdout pipe. */ | |
414 | ||
415 | save_errno = errno; | |
f1e894f3 PH |
416 | (void)close(inpfd[pipe_read]); |
417 | (void)close(outpfd[pipe_write]); | |
059ec3d9 PH |
418 | |
419 | /* Fork succeeded; return the input/output pipes and the pid */ | |
420 | ||
421 | if (pid > 0) | |
422 | { | |
423 | *infdptr = inpfd[pipe_write]; | |
424 | *outfdptr = outpfd[pipe_read]; | |
425 | return pid; | |
426 | } | |
427 | ||
428 | /* Fork failed; reset fork errno before returning */ | |
429 | ||
f1e894f3 PH |
430 | (void)close(inpfd[pipe_write]); |
431 | (void)close(outpfd[pipe_read]); | |
059ec3d9 PH |
432 | errno = save_errno; |
433 | return (pid_t)(-1); | |
434 | } | |
435 | ||
436 | ||
437 | ||
438 | ||
439 | /************************************************* | |
440 | * Create child process without uid change * | |
441 | *************************************************/ | |
442 | ||
443 | /* This function is a wrapper for child_open_uid() that doesn't have the uid, | |
b668c215 PH |
444 | gid and working directory changing arguments. The function is provided so as to |
445 | have a clean interface for use from local_scan(), but also saves writing NULL | |
446 | arguments several calls that would otherwise use child_open_uid(). | |
059ec3d9 PH |
447 | |
448 | Arguments: | |
449 | argv the argv for exec in the new process | |
450 | envp the envp for exec in the new process | |
451 | newumask umask to set in the new process | |
452 | infdptr pointer to int into which the fd of the stdin of the new process | |
453 | is placed | |
454 | outfdptr pointer to int into which the fd of the stdout/stderr of the new | |
455 | process is placed | |
456 | make_leader if TRUE, make the new process a process group leader | |
457 | ||
458 | Returns: the pid of the created process or -1 if anything has gone wrong | |
459 | */ | |
460 | ||
461 | pid_t | |
462 | child_open(uschar **argv, uschar **envp, int newumask, int *infdptr, | |
463 | int *outfdptr, BOOL make_leader) | |
464 | { | |
55414b25 JH |
465 | return child_open_uid(CUSS argv, CUSS envp, newumask, NULL, NULL, |
466 | infdptr, outfdptr, NULL, make_leader); | |
059ec3d9 PH |
467 | } |
468 | ||
469 | ||
470 | ||
471 | ||
472 | /************************************************* | |
473 | * Close down child process * | |
474 | *************************************************/ | |
475 | ||
476 | /* Wait for the given process to finish, with optional timeout. | |
477 | ||
478 | Arguments | |
479 | pid: the pid to wait for | |
480 | timeout: maximum time to wait; 0 means for as long as it takes | |
481 | ||
482 | Returns: >= 0 process terminated by exiting; value is process | |
483 | ending status; if an execve() failed, the value | |
484 | is typically 127 (defined as EX_EXECFAILED) | |
485 | < 0 & > -256 process was terminated by a signal; value is the | |
486 | negation of the signal number | |
487 | -256 timed out | |
488 | -257 other error in wait(); errno still set | |
489 | */ | |
490 | ||
491 | int | |
492 | child_close(pid_t pid, int timeout) | |
493 | { | |
494 | int yield; | |
495 | ||
496 | if (timeout > 0) | |
497 | { | |
498 | sigalrm_seen = FALSE; | |
c2a1bba0 | 499 | ALARM(timeout); |
059ec3d9 PH |
500 | } |
501 | ||
502 | for(;;) | |
503 | { | |
504 | int status; | |
505 | pid_t rc = waitpid(pid, &status, 0); | |
506 | if (rc == pid) | |
507 | { | |
508 | int lowbyte = status & 255; | |
d7625a4d | 509 | yield = lowbyte == 0 ? (status >> 8) & 255 : -lowbyte; |
059ec3d9 PH |
510 | break; |
511 | } | |
512 | if (rc < 0) | |
513 | { | |
d7625a4d JH |
514 | /* This "shouldn't happen" test does happen on MacOS: for some reason |
515 | I do not understand we seems to get an alarm signal despite not having | |
516 | an active alarm set. There seems to be only one, so just go round again. */ | |
517 | ||
518 | if (errno == EINTR && sigalrm_seen && timeout <= 0) continue; | |
519 | ||
520 | yield = (errno == EINTR && sigalrm_seen) ? -256 : -257; | |
059ec3d9 PH |
521 | break; |
522 | } | |
523 | } | |
524 | ||
c2a1bba0 | 525 | if (timeout > 0) ALARM_CLR(0); |
059ec3d9 PH |
526 | |
527 | signal(SIGCHLD, oldsignal); /* restore */ | |
528 | return yield; | |
529 | } | |
530 | ||
531 | /* End of child.c */ |