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0a49a7a4 | 1 | /* $Cambridge: exim/src/src/daemon.c,v 1.27 2009/11/16 19:50:36 nm4 Exp $ */ |
059ec3d9 PH |
2 | |
3 | /************************************************* | |
4 | * Exim - an Internet mail transport agent * | |
5 | *************************************************/ | |
6 | ||
0a49a7a4 | 7 | /* Copyright (c) University of Cambridge 1995 - 2009 */ |
059ec3d9 PH |
8 | /* See the file NOTICE for conditions of use and distribution. */ |
9 | ||
10 | /* Functions concerned with running Exim as a daemon */ | |
11 | ||
12 | ||
13 | #include "exim.h" | |
14 | ||
15 | ||
16 | /* Structure for holding data for each SMTP connection */ | |
17 | ||
18 | typedef struct smtp_slot { | |
19 | pid_t pid; /* pid of the spawned reception process */ | |
20 | uschar *host_address; /* address of the client host */ | |
21 | } smtp_slot; | |
22 | ||
23 | /* An empty slot for initializing (Standard C does not allow constructor | |
24 | expressions in assigments except as initializers in declarations). */ | |
25 | ||
26 | static smtp_slot empty_smtp_slot = { 0, NULL }; | |
27 | ||
28 | ||
29 | ||
30 | /************************************************* | |
31 | * Local static variables * | |
32 | *************************************************/ | |
33 | ||
cd59ab18 PP |
34 | static SIGNAL_BOOL sigchld_seen; |
35 | static SIGNAL_BOOL sighup_seen; | |
059ec3d9 PH |
36 | |
37 | static int accept_retry_count = 0; | |
38 | static int accept_retry_errno; | |
39 | static BOOL accept_retry_select_failed; | |
40 | ||
41 | static int queue_run_count = 0; | |
bb6e88ff PH |
42 | static pid_t *queue_pid_slots = NULL; |
43 | static smtp_slot *smtp_slots = NULL; | |
059ec3d9 PH |
44 | |
45 | static BOOL write_pid = TRUE; | |
46 | ||
47 | ||
48 | ||
49 | /************************************************* | |
50 | * SIGHUP Handler * | |
51 | *************************************************/ | |
52 | ||
53 | /* All this handler does is to set a flag and re-enable the signal. | |
54 | ||
55 | Argument: the signal number | |
56 | Returns: nothing | |
57 | */ | |
58 | ||
59 | static void | |
60 | sighup_handler(int sig) | |
61 | { | |
62 | sig = sig; /* Keep picky compilers happy */ | |
63 | sighup_seen = TRUE; | |
64 | signal(SIGHUP, sighup_handler); | |
65 | } | |
66 | ||
67 | ||
68 | ||
69 | /************************************************* | |
70 | * SIGCHLD handler for main daemon process * | |
71 | *************************************************/ | |
72 | ||
73 | /* Don't re-enable the handler here, since we aren't doing the | |
74 | waiting here. If the signal is re-enabled, there will just be an | |
75 | infinite sequence of calls to this handler. The SIGCHLD signal is | |
76 | used just as a means of waking up the daemon so that it notices | |
77 | terminated subprocesses as soon as possible. | |
78 | ||
79 | Argument: the signal number | |
80 | Returns: nothing | |
81 | */ | |
82 | ||
83 | static void | |
84 | main_sigchld_handler(int sig) | |
85 | { | |
86 | sig = sig; /* Keep picky compilers happy */ | |
7d468ab8 | 87 | os_non_restarting_signal(SIGCHLD, SIG_DFL); |
059ec3d9 | 88 | sigchld_seen = TRUE; |
059ec3d9 PH |
89 | } |
90 | ||
91 | ||
92 | ||
93 | ||
94 | /************************************************* | |
95 | * Unexpected errors in SMTP calls * | |
96 | *************************************************/ | |
97 | ||
98 | /* This function just saves a bit of repetitious coding. | |
99 | ||
100 | Arguments: | |
101 | log_msg Text of message to be logged | |
102 | smtp_msg Text of SMTP error message | |
103 | was_errno The failing errno | |
104 | ||
105 | Returns: nothing | |
106 | */ | |
107 | ||
108 | static void | |
109 | never_error(uschar *log_msg, uschar *smtp_msg, int was_errno) | |
110 | { | |
111 | uschar *emsg = (was_errno <= 0)? US"" : | |
112 | string_sprintf(": %s", strerror(was_errno)); | |
113 | log_write(0, LOG_MAIN|LOG_PANIC, "%s%s", log_msg, emsg); | |
114 | if (smtp_out != NULL) smtp_printf("421 %s\r\n", smtp_msg); | |
115 | } | |
116 | ||
117 | ||
118 | ||
119 | ||
120 | /************************************************* | |
121 | * Handle a connected SMTP call * | |
122 | *************************************************/ | |
123 | ||
124 | /* This function is called when an SMTP connection has been accepted. | |
125 | If there are too many, give an error message and close down. Otherwise | |
126 | spin off a sub-process to handle the call. The list of listening sockets | |
127 | is required so that they can be closed in the sub-process. Take care not to | |
128 | leak store in this process - reset the stacking pool at the end. | |
129 | ||
130 | Arguments: | |
131 | listen_sockets sockets which are listening for incoming calls | |
132 | listen_socket_count count of listening sockets | |
133 | accept_socket socket of the current accepted call | |
134 | accepted socket information about the current call | |
135 | ||
136 | Returns: nothing | |
137 | */ | |
138 | ||
139 | static void | |
140 | handle_smtp_call(int *listen_sockets, int listen_socket_count, | |
141 | int accept_socket, struct sockaddr *accepted) | |
142 | { | |
143 | pid_t pid; | |
144 | union sockaddr_46 interface_sockaddr; | |
36a3b041 | 145 | EXIM_SOCKLEN_T ifsize = sizeof(interface_sockaddr); |
059ec3d9 PH |
146 | int dup_accept_socket = -1; |
147 | int max_for_this_host = 0; | |
148 | int wfsize = 0; | |
149 | int wfptr = 0; | |
150 | int use_log_write_selector = log_write_selector; | |
151 | uschar *whofrom = NULL; | |
152 | ||
153 | void *reset_point = store_get(0); | |
154 | ||
155 | /* Make the address available in ASCII representation, and also fish out | |
156 | the remote port. */ | |
157 | ||
158 | sender_host_address = host_ntoa(-1, accepted, NULL, &sender_host_port); | |
159 | DEBUG(D_any) debug_printf("Connection request from %s port %d\n", | |
160 | sender_host_address, sender_host_port); | |
161 | ||
162 | /* Set up the output stream, check the socket has duplicated, and set up the | |
163 | input stream. These operations fail only the exceptional circumstances. Note | |
164 | that never_error() won't use smtp_out if it is NULL. */ | |
165 | ||
166 | smtp_out = fdopen(accept_socket, "wb"); | |
167 | if (smtp_out == NULL) | |
168 | { | |
169 | never_error(US"daemon: fdopen() for smtp_out failed", US"", errno); | |
170 | goto ERROR_RETURN; | |
171 | } | |
172 | ||
173 | dup_accept_socket = dup(accept_socket); | |
174 | if (dup_accept_socket < 0) | |
175 | { | |
176 | never_error(US"daemon: couldn't dup socket descriptor", | |
177 | US"Connection setup failed", errno); | |
178 | goto ERROR_RETURN; | |
179 | } | |
180 | ||
181 | smtp_in = fdopen(dup_accept_socket, "rb"); | |
182 | if (smtp_in == NULL) | |
183 | { | |
184 | never_error(US"daemon: fdopen() for smtp_in failed", | |
185 | US"Connection setup failed", errno); | |
186 | goto ERROR_RETURN; | |
187 | } | |
188 | ||
520de300 PH |
189 | /* Get the data for the local interface address. Panic for most errors, but |
190 | "connection reset by peer" just means the connection went away. */ | |
059ec3d9 PH |
191 | |
192 | if (getsockname(accept_socket, (struct sockaddr *)(&interface_sockaddr), | |
193 | &ifsize) < 0) | |
194 | { | |
520de300 PH |
195 | log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC), |
196 | "getsockname() failed: %s", strerror(errno)); | |
059ec3d9 PH |
197 | smtp_printf("421 Local problem: getsockname() failed; please try again later\r\n"); |
198 | goto ERROR_RETURN; | |
199 | } | |
200 | ||
201 | interface_address = host_ntoa(-1, &interface_sockaddr, NULL, &interface_port); | |
202 | DEBUG(D_interface) debug_printf("interface address=%s port=%d\n", | |
203 | interface_address, interface_port); | |
204 | ||
205 | /* Build a string identifying the remote host and, if requested, the port and | |
206 | the local interface data. This is for logging; at the end of this function the | |
207 | memory is reclaimed. */ | |
208 | ||
209 | whofrom = string_append(whofrom, &wfsize, &wfptr, 3, "[", sender_host_address, "]"); | |
210 | ||
211 | if ((log_extra_selector & LX_incoming_port) != 0) | |
212 | whofrom = string_append(whofrom, &wfsize, &wfptr, 2, ":", string_sprintf("%d", | |
213 | sender_host_port)); | |
214 | ||
215 | if ((log_extra_selector & LX_incoming_interface) != 0) | |
216 | whofrom = string_append(whofrom, &wfsize, &wfptr, 4, " I=[", | |
217 | interface_address, "]:", string_sprintf("%d", interface_port)); | |
218 | ||
219 | whofrom[wfptr] = 0; /* Terminate the newly-built string */ | |
220 | ||
221 | /* Check maximum number of connections. We do not check for reserved | |
222 | connections or unacceptable hosts here. That is done in the subprocess because | |
223 | it might take some time. */ | |
224 | ||
225 | if (smtp_accept_max > 0 && smtp_accept_count >= smtp_accept_max) | |
226 | { | |
227 | DEBUG(D_any) debug_printf("rejecting SMTP connection: count=%d max=%d\n", | |
228 | smtp_accept_count, smtp_accept_max); | |
229 | smtp_printf("421 Too many concurrent SMTP connections; " | |
230 | "please try again later.\r\n"); | |
231 | log_write(L_connection_reject, | |
232 | LOG_MAIN, "Connection from %s refused: too many connections", | |
233 | whofrom); | |
234 | goto ERROR_RETURN; | |
235 | } | |
236 | ||
237 | /* If a load limit above which only reserved hosts are acceptable is defined, | |
238 | get the load average here, and if there are in fact no reserved hosts, do | |
239 | the test right away (saves a fork). If there are hosts, do the check in the | |
240 | subprocess because it might take time. */ | |
241 | ||
242 | if (smtp_load_reserve >= 0) | |
243 | { | |
8669f003 | 244 | load_average = OS_GETLOADAVG(); |
059ec3d9 PH |
245 | if (smtp_reserve_hosts == NULL && load_average > smtp_load_reserve) |
246 | { | |
247 | DEBUG(D_any) debug_printf("rejecting SMTP connection: load average = %.2f\n", | |
248 | (double)load_average/1000.0); | |
249 | smtp_printf("421 Too much load; please try again later.\r\n"); | |
250 | log_write(L_connection_reject, | |
251 | LOG_MAIN, "Connection from %s refused: load average = %.2f", | |
252 | whofrom, (double)load_average/1000.0); | |
253 | goto ERROR_RETURN; | |
254 | } | |
255 | } | |
256 | ||
257 | /* Check that one specific host (strictly, IP address) is not hogging | |
258 | resources. This is done here to prevent a denial of service attack by someone | |
259 | forcing you to fork lots of times before denying service. The value of | |
260 | smtp_accept_max_per_host is a string which is expanded. This makes it possible | |
261 | to provide host-specific limits according to $sender_host address, but because | |
262 | this is in the daemon mainline, only fast expansions (such as inline address | |
263 | checks) should be used. The documentation is full of warnings. */ | |
264 | ||
265 | if (smtp_accept_max_per_host != NULL) | |
266 | { | |
267 | uschar *expanded = expand_string(smtp_accept_max_per_host); | |
268 | if (expanded == NULL) | |
269 | { | |
270 | if (!expand_string_forcedfail) | |
271 | log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host " | |
272 | "failed for %s: %s", whofrom, expand_string_message); | |
273 | } | |
274 | /* For speed, interpret a decimal number inline here */ | |
275 | else | |
276 | { | |
277 | uschar *s = expanded; | |
278 | while (isdigit(*s)) | |
279 | max_for_this_host = max_for_this_host * 10 + *s++ - '0'; | |
280 | if (*s != 0) | |
281 | log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host " | |
282 | "for %s contains non-digit: %s", whofrom, expanded); | |
283 | } | |
284 | } | |
285 | ||
286 | /* If we have fewer connections than max_for_this_host, we can skip the tedious | |
287 | per host_address checks. Note that at this stage smtp_accept_count contains the | |
288 | count of *other* connections, not including this one. */ | |
289 | ||
290 | if ((max_for_this_host > 0) && | |
291 | (smtp_accept_count >= max_for_this_host)) | |
292 | { | |
293 | int i; | |
294 | int host_accept_count = 0; | |
295 | int other_host_count = 0; /* keep a count of non matches to optimise */ | |
296 | ||
297 | for (i = 0; i < smtp_accept_max; ++i) | |
298 | { | |
299 | if (smtp_slots[i].host_address != NULL) | |
300 | { | |
301 | if (Ustrcmp(sender_host_address, smtp_slots[i].host_address) == 0) | |
302 | host_accept_count++; | |
303 | else | |
304 | other_host_count++; | |
305 | ||
306 | /* Testing all these strings is expensive - see if we can drop out | |
307 | early, either by hitting the target, or finding there are not enough | |
308 | connections left to make the target. */ | |
309 | ||
310 | if ((host_accept_count >= max_for_this_host) || | |
311 | ((smtp_accept_count - other_host_count) < max_for_this_host)) | |
312 | break; | |
313 | } | |
314 | } | |
315 | ||
316 | if (host_accept_count >= max_for_this_host) | |
317 | { | |
318 | DEBUG(D_any) debug_printf("rejecting SMTP connection: too many from this " | |
319 | "IP address: count=%d max=%d\n", | |
320 | host_accept_count, max_for_this_host); | |
321 | smtp_printf("421 Too many concurrent SMTP connections " | |
322 | "from this IP address; please try again later.\r\n"); | |
323 | log_write(L_connection_reject, | |
324 | LOG_MAIN, "Connection from %s refused: too many connections " | |
325 | "from that IP address", whofrom); | |
326 | goto ERROR_RETURN; | |
327 | } | |
328 | } | |
329 | ||
330 | /* OK, the connection count checks have been passed. Before we can fork the | |
331 | accepting process, we must first log the connection if requested. This logging | |
332 | used to happen in the subprocess, but doing that means that the value of | |
333 | smtp_accept_count can be out of step by the time it is logged. So we have to do | |
334 | the logging here and accept the performance cost. Note that smtp_accept_count | |
335 | hasn't yet been incremented to take account of this connection. | |
336 | ||
337 | In order to minimize the cost (because this is going to happen for every | |
338 | connection), do a preliminary selector test here. This saves ploughing through | |
339 | the generalized logging code each time when the selector is false. If the | |
340 | selector is set, check whether the host is on the list for logging. If not, | |
341 | arrange to unset the selector in the subprocess. */ | |
342 | ||
343 | if ((log_write_selector & L_smtp_connection) != 0) | |
344 | { | |
345 | uschar *list = hosts_connection_nolog; | |
346 | if (list != NULL && verify_check_host(&list) == OK) | |
347 | use_log_write_selector &= ~L_smtp_connection; | |
348 | else | |
349 | log_write(L_smtp_connection, LOG_MAIN, "SMTP connection from %s " | |
350 | "(TCP/IP connection count = %d)", whofrom, smtp_accept_count + 1); | |
351 | } | |
352 | ||
353 | /* Now we can fork the accepting process; do a lookup tidy, just in case any | |
354 | expansion above did a lookup. */ | |
355 | ||
356 | search_tidyup(); | |
357 | pid = fork(); | |
358 | ||
359 | /* Handle the child process */ | |
360 | ||
361 | if (pid == 0) | |
362 | { | |
363 | int i; | |
364 | int queue_only_reason = 0; | |
365 | int old_pool = store_pool; | |
8e669ac1 | 366 | int save_debug_selector = debug_selector; |
059ec3d9 | 367 | BOOL local_queue_only; |
8669f003 | 368 | BOOL session_local_queue_only; |
059ec3d9 PH |
369 | #ifdef SA_NOCLDWAIT |
370 | struct sigaction act; | |
371 | #endif | |
372 | ||
b01dd148 PH |
373 | smtp_accept_count++; /* So that it includes this process */ |
374 | ||
059ec3d9 PH |
375 | /* May have been modified for the subprocess */ |
376 | ||
377 | log_write_selector = use_log_write_selector; | |
378 | ||
379 | /* Get the local interface address into permanent store */ | |
380 | ||
381 | store_pool = POOL_PERM; | |
382 | interface_address = string_copy(interface_address); | |
383 | store_pool = old_pool; | |
384 | ||
385 | /* Check for a tls-on-connect port */ | |
386 | ||
387 | if (host_is_tls_on_connect_port(interface_port)) tls_on_connect = TRUE; | |
388 | ||
389 | /* Expand smtp_active_hostname if required. We do not do this any earlier, | |
390 | because it may depend on the local interface address (indeed, that is most | |
391 | likely what it depends on.) */ | |
392 | ||
393 | smtp_active_hostname = primary_hostname; | |
394 | if (raw_active_hostname != NULL) | |
395 | { | |
396 | uschar *nah = expand_string(raw_active_hostname); | |
397 | if (nah == NULL) | |
398 | { | |
399 | if (!expand_string_forcedfail) | |
400 | { | |
401 | log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand \"%s\" " | |
402 | "(smtp_active_hostname): %s", raw_active_hostname, | |
403 | expand_string_message); | |
404 | smtp_printf("421 Local configuration error; " | |
405 | "please try again later.\r\n"); | |
406 | mac_smtp_fflush(); | |
407 | search_tidyup(); | |
408 | _exit(EXIT_FAILURE); | |
409 | } | |
410 | } | |
411 | else if (nah[0] != 0) smtp_active_hostname = nah; | |
412 | } | |
413 | ||
414 | /* Initialize the queueing flags */ | |
415 | ||
416 | queue_check_only(); | |
8669f003 | 417 | session_local_queue_only = queue_only; |
059ec3d9 PH |
418 | |
419 | /* Close the listening sockets, and set the SIGCHLD handler to SIG_IGN. | |
420 | We also attempt to set things up so that children are automatically reaped, | |
421 | but just in case this isn't available, there's a paranoid waitpid() in the | |
422 | loop too (except for systems where we are sure it isn't needed). See the more | |
423 | extensive comment before the reception loop in exim.c for a fuller | |
424 | explanation of this logic. */ | |
425 | ||
f1e894f3 | 426 | for (i = 0; i < listen_socket_count; i++) (void)close(listen_sockets[i]); |
059ec3d9 | 427 | |
fa32850b DW |
428 | /* Set FD_CLOEXEC on the SMTP socket. We don't want any rogue child processes |
429 | to be able to communicate with them, under any circumstances. */ | |
430 | (void)fcntl(accept_socket, F_SETFD, | |
431 | fcntl(accept_socket, F_GETFD) | FD_CLOEXEC); | |
432 | (void)fcntl(dup_accept_socket, F_SETFD, | |
433 | fcntl(dup_accept_socket, F_GETFD) | FD_CLOEXEC); | |
434 | ||
059ec3d9 PH |
435 | #ifdef SA_NOCLDWAIT |
436 | act.sa_handler = SIG_IGN; | |
437 | sigemptyset(&(act.sa_mask)); | |
438 | act.sa_flags = SA_NOCLDWAIT; | |
439 | sigaction(SIGCHLD, &act, NULL); | |
440 | #else | |
441 | signal(SIGCHLD, SIG_IGN); | |
442 | #endif | |
443 | ||
444 | /* Attempt to get an id from the sending machine via the RFC 1413 | |
445 | protocol. We do this in the sub-process in order not to hold up the | |
446 | main process if there is any delay. Then set up the fullhost information | |
8e669ac1 PH |
447 | in case there is no HELO/EHLO. |
448 | ||
449 | If debugging is enabled only for the daemon, we must turn if off while | |
450 | finding the id, but turn it on again afterwards so that information about the | |
3d235903 | 451 | incoming connection is output. */ |
8e669ac1 | 452 | |
3d235903 | 453 | if (debug_daemon) debug_selector = 0; |
059ec3d9 PH |
454 | verify_get_ident(IDENT_PORT); |
455 | host_build_sender_fullhost(); | |
8e669ac1 | 456 | debug_selector = save_debug_selector; |
059ec3d9 PH |
457 | |
458 | DEBUG(D_any) | |
459 | debug_printf("Process %d is handling incoming connection from %s\n", | |
460 | (int)getpid(), sender_fullhost); | |
461 | ||
3d235903 PH |
462 | /* Now disable debugging permanently if it's required only for the daemon |
463 | process. */ | |
464 | ||
465 | if (debug_daemon) debug_selector = 0; | |
466 | ||
059ec3d9 | 467 | /* If there are too many child processes for immediate delivery, |
8669f003 | 468 | set the session_local_queue_only flag, which is initialized from the |
059ec3d9 | 469 | configured value and may therefore already be TRUE. Leave logging |
8669f003 PH |
470 | till later so it will have a message id attached. Note that there is no |
471 | possibility of re-calculating this per-message, because the value of | |
472 | smtp_accept_count does not change in this subprocess. */ | |
059ec3d9 | 473 | |
b01dd148 | 474 | if (smtp_accept_queue > 0 && smtp_accept_count > smtp_accept_queue) |
059ec3d9 | 475 | { |
8669f003 | 476 | session_local_queue_only = TRUE; |
059ec3d9 PH |
477 | queue_only_reason = 1; |
478 | } | |
479 | ||
480 | /* Handle the start of the SMTP session, then loop, accepting incoming | |
481 | messages from the SMTP connection. The end will come at the QUIT command, | |
482 | when smtp_setup_msg() returns 0. A break in the connection causes the | |
24796b8d PH |
483 | process to die (see accept.c). |
484 | ||
485 | NOTE: We do *not* call smtp_log_no_mail() if smtp_start_session() fails, | |
486 | because a log line has already been written for all its failure exists | |
487 | (usually "connection refused: <reason>") and writing another one is | |
488 | unnecessary clutter. */ | |
059ec3d9 PH |
489 | |
490 | if (!smtp_start_session()) | |
491 | { | |
492 | mac_smtp_fflush(); | |
493 | search_tidyup(); | |
494 | _exit(EXIT_SUCCESS); | |
495 | } | |
496 | ||
497 | for (;;) | |
498 | { | |
499 | int rc; | |
500 | message_id[0] = 0; /* Clear out any previous message_id */ | |
501 | reset_point = store_get(0); /* Save current store high water point */ | |
502 | ||
503 | DEBUG(D_any) | |
504 | debug_printf("Process %d is ready for new message\n", (int)getpid()); | |
505 | ||
506 | /* Smtp_setup_msg() returns 0 on QUIT or if the call is from an | |
507 | unacceptable host or if an ACL "drop" command was triggered, -1 on | |
508 | connection lost, and +1 on validly reaching DATA. Receive_msg() almost | |
509 | always returns TRUE when smtp_input is true; just retry if no message was | |
510 | accepted (can happen for invalid message parameters). However, it can yield | |
511 | FALSE if the connection was forcibly dropped by the DATA ACL. */ | |
512 | ||
513 | if ((rc = smtp_setup_msg()) > 0) | |
514 | { | |
515 | BOOL ok = receive_msg(FALSE); | |
516 | search_tidyup(); /* Close cached databases */ | |
517 | if (!ok) /* Connection was dropped */ | |
518 | { | |
519 | mac_smtp_fflush(); | |
b4ed4da0 | 520 | smtp_log_no_mail(); /* Log no mail if configured */ |
059ec3d9 PH |
521 | _exit(EXIT_SUCCESS); |
522 | } | |
523 | if (message_id[0] == 0) continue; /* No message was accepted */ | |
524 | } | |
525 | else | |
526 | { | |
527 | mac_smtp_fflush(); | |
528 | search_tidyup(); | |
b4ed4da0 | 529 | smtp_log_no_mail(); /* Log no mail if configured */ |
059ec3d9 PH |
530 | _exit((rc == 0)? EXIT_SUCCESS : EXIT_FAILURE); |
531 | } | |
532 | ||
533 | /* Show the recipients when debugging */ | |
534 | ||
535 | DEBUG(D_receive) | |
536 | { | |
537 | int i; | |
538 | if (sender_address != NULL) | |
539 | debug_printf("Sender: %s\n", sender_address); | |
540 | if (recipients_list != NULL) | |
541 | { | |
542 | debug_printf("Recipients:\n"); | |
543 | for (i = 0; i < recipients_count; i++) | |
544 | debug_printf(" %s\n", recipients_list[i].address); | |
545 | } | |
546 | } | |
547 | ||
548 | /* A message has been accepted. Clean up any previous delivery processes | |
549 | that have completed and are defunct, on systems where they don't go away | |
550 | by themselves (see comments when setting SIG_IGN above). On such systems | |
551 | (if any) these delivery processes hang around after termination until | |
552 | the next message is received. */ | |
553 | ||
554 | #ifndef SIG_IGN_WORKS | |
555 | while (waitpid(-1, NULL, WNOHANG) > 0); | |
556 | #endif | |
557 | ||
558 | /* Reclaim up the store used in accepting this message */ | |
559 | ||
560 | store_reset(reset_point); | |
561 | ||
562 | /* If queue_only is set or if there are too many incoming connections in | |
8669f003 PH |
563 | existence, session_local_queue_only will be TRUE. If it is not, check |
564 | whether we have received too many messages in this session for immediate | |
565 | delivery. */ | |
566 | ||
567 | if (!session_local_queue_only && | |
568 | smtp_accept_queue_per_connection > 0 && | |
569 | receive_messagecount > smtp_accept_queue_per_connection) | |
059ec3d9 | 570 | { |
8669f003 PH |
571 | session_local_queue_only = TRUE; |
572 | queue_only_reason = 2; | |
573 | } | |
574 | ||
575 | /* Initialize local_queue_only from session_local_queue_only. If it is not | |
576 | true, and queue_only_load is set, check that the load average is below it. | |
577 | If local_queue_only is set by this means, we also set if for the session if | |
578 | queue_only_load_latch is true (the default). This means that, once set, | |
579 | local_queue_only remains set for any subsequent messages on the same SMTP | |
580 | connection. This is a deliberate choice; even though the load average may | |
581 | fall, it doesn't seem right to deliver later messages on the same call when | |
582 | not delivering earlier ones. However, the are special circumstances such as | |
583 | very long-lived connections from scanning appliances where this is not the | |
584 | best strategy. In such cases, queue_only_load_latch should be set false. */ | |
585 | ||
586 | local_queue_only = session_local_queue_only; | |
587 | if (!local_queue_only && queue_only_load >= 0) | |
588 | { | |
589 | local_queue_only = (load_average = OS_GETLOADAVG()) > queue_only_load; | |
590 | if (local_queue_only) | |
059ec3d9 | 591 | { |
8669f003 PH |
592 | queue_only_reason = 3; |
593 | if (queue_only_load_latch) session_local_queue_only = TRUE; | |
059ec3d9 PH |
594 | } |
595 | } | |
596 | ||
597 | /* Log the queueing here, when it will get a message id attached, but | |
598 | not if queue_only is set (case 0). */ | |
599 | ||
600 | if (local_queue_only) switch(queue_only_reason) | |
601 | { | |
602 | case 1: | |
603 | log_write(L_delay_delivery, | |
604 | LOG_MAIN, "no immediate delivery: too many connections " | |
605 | "(%d, max %d)", smtp_accept_count, smtp_accept_queue); | |
606 | break; | |
607 | ||
608 | case 2: | |
609 | log_write(L_delay_delivery, | |
610 | LOG_MAIN, "no immediate delivery: more than %d messages " | |
611 | "received in one connection", smtp_accept_queue_per_connection); | |
612 | break; | |
613 | ||
614 | case 3: | |
615 | log_write(L_delay_delivery, | |
616 | LOG_MAIN, "no immediate delivery: load average %.2f", | |
617 | (double)load_average/1000.0); | |
618 | break; | |
619 | } | |
620 | ||
621 | /* If a delivery attempt is required, spin off a new process to handle it. | |
622 | If we are not root, we have to re-exec exim unless deliveries are being | |
623 | done unprivileged. */ | |
624 | ||
625 | else if (!queue_only_policy && !deliver_freeze) | |
626 | { | |
627 | pid_t dpid; | |
628 | ||
629 | /* Before forking, ensure that the C output buffer is flushed. Otherwise | |
630 | anything that it in it will get duplicated, leading to duplicate copies | |
631 | of the pending output. */ | |
632 | ||
633 | mac_smtp_fflush(); | |
634 | ||
635 | if ((dpid = fork()) == 0) | |
636 | { | |
f1e894f3 PH |
637 | (void)fclose(smtp_in); |
638 | (void)fclose(smtp_out); | |
059ec3d9 PH |
639 | |
640 | /* Don't ever molest the parent's SSL connection, but do clean up | |
641 | the data structures if necessary. */ | |
642 | ||
643 | #ifdef SUPPORT_TLS | |
644 | tls_close(FALSE); | |
645 | #endif | |
646 | ||
647 | /* Reset SIGHUP and SIGCHLD in the child in both cases. */ | |
648 | ||
649 | signal(SIGHUP, SIG_DFL); | |
650 | signal(SIGCHLD, SIG_DFL); | |
651 | ||
652 | if (geteuid() != root_uid && !deliver_drop_privilege) | |
653 | { | |
654 | signal(SIGALRM, SIG_DFL); | |
655 | (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 2, US"-Mc", | |
656 | message_id); | |
657 | /* Control does not return here. */ | |
658 | } | |
659 | ||
660 | /* No need to re-exec; SIGALRM remains set to the default handler */ | |
661 | ||
662 | (void)deliver_message(message_id, FALSE, FALSE); | |
663 | search_tidyup(); | |
664 | _exit(EXIT_SUCCESS); | |
665 | } | |
666 | ||
667 | if (dpid > 0) | |
668 | { | |
669 | DEBUG(D_any) debug_printf("forked delivery process %d\n", (int)dpid); | |
670 | } | |
671 | else | |
672 | { | |
673 | log_write(0, LOG_MAIN|LOG_PANIC, "daemon: delivery process fork " | |
674 | "failed: %s", strerror(errno)); | |
675 | } | |
676 | } | |
677 | } | |
678 | } | |
679 | ||
680 | ||
681 | /* Carrying on in the parent daemon process... Can't do much if the fork | |
682 | failed. Otherwise, keep count of the number of accepting processes and | |
683 | remember the pid for ticking off when the child completes. */ | |
684 | ||
685 | if (pid < 0) | |
686 | { | |
687 | never_error(US"daemon: accept process fork failed", US"Fork failed", errno); | |
688 | } | |
689 | else | |
690 | { | |
691 | int i; | |
692 | for (i = 0; i < smtp_accept_max; ++i) | |
693 | { | |
694 | if (smtp_slots[i].pid <= 0) | |
695 | { | |
696 | smtp_slots[i].pid = pid; | |
697 | if (smtp_accept_max_per_host != NULL) | |
698 | smtp_slots[i].host_address = string_copy_malloc(sender_host_address); | |
699 | smtp_accept_count++; | |
700 | break; | |
701 | } | |
702 | } | |
703 | DEBUG(D_any) debug_printf("%d SMTP accept process%s running\n", | |
704 | smtp_accept_count, (smtp_accept_count == 1)? "" : "es"); | |
705 | } | |
706 | ||
707 | /* Get here via goto in error cases */ | |
708 | ||
709 | ERROR_RETURN: | |
710 | ||
711 | /* Close the streams associated with the socket which will also close the | |
712 | socket fds in this process. We can't do anything if fclose() fails, but | |
713 | logging brings it to someone's attention. However, "connection reset by peer" | |
1f872c80 PH |
714 | isn't really a problem, so skip that one. On Solaris, a dropped connection can |
715 | manifest itself as a broken pipe, so drop that one too. If the streams don't | |
716 | exist, something went wrong while setting things up. Make sure the socket | |
717 | descriptors are closed, in order to drop the connection. */ | |
059ec3d9 PH |
718 | |
719 | if (smtp_out != NULL) | |
720 | { | |
1f872c80 | 721 | if (fclose(smtp_out) != 0 && errno != ECONNRESET && errno != EPIPE) |
059ec3d9 PH |
722 | log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_out) failed: %s", |
723 | strerror(errno)); | |
724 | smtp_out = NULL; | |
725 | } | |
f1e894f3 | 726 | else (void)close(accept_socket); |
059ec3d9 PH |
727 | |
728 | if (smtp_in != NULL) | |
729 | { | |
1f872c80 | 730 | if (fclose(smtp_in) != 0 && errno != ECONNRESET && errno != EPIPE) |
059ec3d9 PH |
731 | log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_in) failed: %s", |
732 | strerror(errno)); | |
733 | smtp_in = NULL; | |
734 | } | |
f1e894f3 | 735 | else (void)close(dup_accept_socket); |
059ec3d9 PH |
736 | |
737 | /* Release any store used in this process, including the store used for holding | |
738 | the incoming host address and an expanded active_hostname. */ | |
739 | ||
740 | store_reset(reset_point); | |
741 | sender_host_address = NULL; | |
742 | } | |
743 | ||
744 | ||
745 | ||
746 | ||
747 | /************************************************* | |
748 | * Check wildcard listen special cases * | |
749 | *************************************************/ | |
750 | ||
751 | /* This function is used when binding and listening on lists of addresses and | |
752 | ports. It tests for special cases of wildcard listening, when IPv4 and IPv6 | |
753 | sockets may interact in different ways in different operating systems. It is | |
754 | passed an error number, the list of listening addresses, and the current | |
755 | address. Two checks are available: for a previous wildcard IPv6 address, or for | |
756 | a following wildcard IPv4 address, in both cases on the same port. | |
757 | ||
758 | In practice, pairs of wildcard addresses should be adjacent in the address list | |
759 | because they are sorted that way below. | |
760 | ||
761 | Arguments: | |
762 | eno the error number | |
763 | addresses the list of addresses | |
764 | ipa the current IP address | |
765 | back if TRUE, check for previous wildcard IPv6 address | |
766 | if FALSE, check for a following wildcard IPv4 address | |
767 | ||
768 | Returns: TRUE or FALSE | |
769 | */ | |
770 | ||
771 | static BOOL | |
772 | check_special_case(int eno, ip_address_item *addresses, ip_address_item *ipa, | |
773 | BOOL back) | |
774 | { | |
775 | ip_address_item *ipa2; | |
776 | ||
777 | /* For the "back" case, if the failure was "address in use" for a wildcard IPv4 | |
778 | address, seek a previous IPv6 wildcard address on the same port. As it is | |
779 | previous, it must have been successfully bound and be listening. Flag it as a | |
780 | "6 including 4" listener. */ | |
781 | ||
782 | if (back) | |
783 | { | |
784 | if (eno != EADDRINUSE || ipa->address[0] != 0) return FALSE; | |
785 | for (ipa2 = addresses; ipa2 != ipa; ipa2 = ipa2->next) | |
786 | { | |
787 | if (ipa2->address[1] == 0 && ipa2->port == ipa->port) | |
788 | { | |
789 | ipa2->v6_include_v4 = TRUE; | |
790 | return TRUE; | |
791 | } | |
792 | } | |
793 | } | |
794 | ||
795 | /* For the "forward" case, if the current address is a wildcard IPv6 address, | |
796 | we seek a following wildcard IPv4 address on the same port. */ | |
797 | ||
798 | else | |
799 | { | |
800 | if (ipa->address[0] != ':' || ipa->address[1] != 0) return FALSE; | |
801 | for (ipa2 = ipa->next; ipa2 != NULL; ipa2 = ipa2->next) | |
802 | if (ipa2->address[0] == 0 && ipa->port == ipa2->port) return TRUE; | |
803 | } | |
804 | ||
805 | return FALSE; | |
806 | } | |
807 | ||
808 | ||
809 | ||
810 | ||
bb6e88ff PH |
811 | /************************************************* |
812 | * Handle terminating subprocesses * | |
813 | *************************************************/ | |
814 | ||
815 | /* Handle the termination of child processes. Theoretically, this need be done | |
816 | only when sigchld_seen is TRUE, but rumour has it that some systems lose | |
817 | SIGCHLD signals at busy times, so to be on the safe side, this function is | |
818 | called each time round. It shouldn't be too expensive. | |
819 | ||
820 | Arguments: none | |
821 | Returns: nothing | |
822 | */ | |
823 | ||
824 | static void | |
825 | handle_ending_processes(void) | |
826 | { | |
827 | int status; | |
828 | pid_t pid; | |
829 | ||
830 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) | |
831 | { | |
832 | int i; | |
833 | DEBUG(D_any) debug_printf("child %d ended: status=0x%x\n", (int)pid, | |
834 | status); | |
835 | ||
8e669ac1 | 836 | /* If it's a listening daemon for which we are keeping track of individual |
bb6e88ff PH |
837 | subprocesses, deal with an accepting process that has terminated. */ |
838 | ||
839 | if (smtp_slots != NULL) | |
840 | { | |
841 | for (i = 0; i < smtp_accept_max; i++) | |
842 | { | |
843 | if (smtp_slots[i].pid == pid) | |
844 | { | |
845 | if (smtp_slots[i].host_address != NULL) | |
846 | store_free(smtp_slots[i].host_address); | |
847 | smtp_slots[i] = empty_smtp_slot; | |
848 | if (--smtp_accept_count < 0) smtp_accept_count = 0; | |
849 | DEBUG(D_any) debug_printf("%d SMTP accept process%s now running\n", | |
850 | smtp_accept_count, (smtp_accept_count == 1)? "" : "es"); | |
851 | break; | |
852 | } | |
853 | } | |
854 | if (i < smtp_accept_max) continue; /* Found an accepting process */ | |
855 | } | |
856 | ||
857 | /* If it wasn't an accepting process, see if it was a queue-runner | |
858 | process that we are tracking. */ | |
859 | ||
860 | if (queue_pid_slots != NULL) | |
861 | { | |
862 | for (i = 0; i < queue_run_max; i++) | |
863 | { | |
864 | if (queue_pid_slots[i] == pid) | |
865 | { | |
866 | queue_pid_slots[i] = 0; | |
867 | if (--queue_run_count < 0) queue_run_count = 0; | |
868 | DEBUG(D_any) debug_printf("%d queue-runner process%s now running\n", | |
869 | queue_run_count, (queue_run_count == 1)? "" : "es"); | |
870 | break; | |
871 | } | |
872 | } | |
873 | } | |
874 | } | |
875 | } | |
876 | ||
059ec3d9 PH |
877 | |
878 | ||
879 | /************************************************* | |
880 | * Exim Daemon Mainline * | |
881 | *************************************************/ | |
882 | ||
883 | /* The daemon can do two jobs, either of which is optional: | |
884 | ||
885 | (1) Listens for incoming SMTP calls and spawns off a sub-process to handle | |
886 | each one. This is requested by the -bd option, with -oX specifying the SMTP | |
887 | port on which to listen (for testing). | |
888 | ||
889 | (2) Spawns a queue-running process every so often. This is controlled by the | |
890 | -q option with a an interval time. (If no time is given, a single queue run | |
891 | is done from the main function, and control doesn't get here.) | |
892 | ||
893 | Root privilege is required in order to attach to port 25. Some systems require | |
894 | it when calling socket() rather than bind(). To cope with all cases, we run as | |
895 | root for both socket() and bind(). Some systems also require root in order to | |
896 | write to the pid file directory. This function must therefore be called as root | |
897 | if it is to work properly in all circumstances. Once the socket is bound and | |
898 | the pid file written, root privilege is given up if there is an exim uid. | |
899 | ||
900 | There are no arguments to this function, and it never returns. */ | |
901 | ||
902 | void | |
903 | daemon_go(void) | |
904 | { | |
ebeaf996 | 905 | struct passwd *pw; |
059ec3d9 PH |
906 | int *listen_sockets = NULL; |
907 | int listen_socket_count = 0; | |
908 | ip_address_item *addresses = NULL; | |
909 | ||
910 | /* If any debugging options are set, turn on the D_pid bit so that all | |
911 | debugging lines get the pid added. */ | |
912 | ||
913 | DEBUG(D_any|D_v) debug_selector |= D_pid; | |
914 | ||
915 | ||
916 | /* Do the preparation for setting up a listener on one or more interfaces, and | |
917 | possible on various ports. This is controlled by the combination of | |
918 | local_interfaces (which can set IP addresses and ports) and daemon_smtp_port | |
919 | (which is a list of default ports to use for those items in local_interfaces | |
920 | that do not specify a port). The -oX command line option can be used to | |
921 | override one or both of these options. | |
922 | ||
923 | If local_interfaces is not set, the default is to listen on all interfaces. | |
924 | When it is set, it can include "all IPvx interfaces" as an item. This is useful | |
925 | when different ports are in use. | |
926 | ||
927 | It turns out that listening on all interfaces is messy in an IPv6 world, | |
928 | because several different implementation approaches have been taken. This code | |
929 | is now supposed to work with all of them. The point of difference is whether an | |
930 | IPv6 socket that is listening on all interfaces will receive incoming IPv4 | |
931 | calls or not. We also have to cope with the case when IPv6 libraries exist, but | |
932 | there is no IPv6 support in the kernel. | |
933 | ||
934 | . On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped | |
935 | addresses. However, if an IPv4 socket is also listening on all interfaces, | |
936 | calls are directed to the appropriate socket. | |
937 | ||
938 | . On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and | |
939 | give them as mapped addresses, but an attempt also to listen on an IPv4 | |
940 | socket on all interfaces causes an error. | |
941 | ||
942 | . On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up | |
943 | two sockets if you want to accept both kinds of call. | |
944 | ||
945 | . FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which | |
946 | can be turned off, to make it behave like the versions of Linux described | |
947 | above. | |
948 | ||
949 | . I heard a report that the USAGI IPv6 stack for Linux has implemented | |
950 | IPV6_V6ONLY. | |
951 | ||
952 | So, what we do when IPv6 is supported is as follows: | |
953 | ||
954 | (1) After it is set up, the list of interfaces is scanned for wildcard | |
955 | addresses. If an IPv6 and an IPv4 wildcard are both found for the same | |
956 | port, the list is re-arranged so that they are together, with the IPv6 | |
957 | wildcard first. | |
958 | ||
959 | (2) If the creation of a wildcard IPv6 socket fails, we just log the error and | |
960 | carry on if an IPv4 wildcard socket for the same port follows later in the | |
961 | list. This allows Exim to carry on in the case when the kernel has no IPv6 | |
962 | support. | |
963 | ||
964 | (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that | |
965 | option is defined. However, if setting fails, carry on regardless (but log | |
966 | the incident). | |
967 | ||
968 | (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious | |
969 | error. | |
970 | ||
971 | (5) If binding or listening on an IPv4 wildcard socket fails with the error | |
972 | EADDRINUSE, and a previous interface was an IPv6 wildcard for the same | |
973 | port (which must have succeeded or we wouldn't have got this far), we | |
974 | assume we are in the situation where just a single socket is permitted, | |
975 | and ignore the error. | |
976 | ||
977 | Phew! | |
978 | ||
979 | The preparation code decodes options and sets up the relevant data. We do this | |
980 | first, so that we can return non-zero if there are any syntax errors, and also | |
981 | write to stderr. */ | |
982 | ||
983 | if (daemon_listen) | |
984 | { | |
985 | int *default_smtp_port; | |
986 | int sep; | |
987 | int pct = 0; | |
988 | uschar *s; | |
989 | uschar *list; | |
990 | uschar *local_iface_source = US"local_interfaces"; | |
991 | ip_address_item *ipa; | |
992 | ip_address_item **pipa; | |
993 | ||
994 | /* If any option requiring a load average to be available during the | |
995 | reception of a message is set, call os_getloadavg() while we are root | |
996 | for those OS for which this is necessary the first time it is called (in | |
997 | order to perform an "open" on the kernel memory file). */ | |
998 | ||
999 | #ifdef LOAD_AVG_NEEDS_ROOT | |
d95f9fdb | 1000 | if (queue_only_load >= 0 || smtp_load_reserve >= 0 || |
8e669ac1 | 1001 | (deliver_queue_load_max >= 0 && deliver_drop_privilege)) |
d95f9fdb | 1002 | (void)os_getloadavg(); |
059ec3d9 PH |
1003 | #endif |
1004 | ||
1005 | /* If -oX was used, disable the writing of a pid file unless -oP was | |
1006 | explicitly used to force it. Then scan the string given to -oX. Any items | |
1007 | that contain neither a dot nor a colon are used to override daemon_smtp_port. | |
1008 | Any other items are used to override local_interfaces. */ | |
1009 | ||
1010 | if (override_local_interfaces != NULL) | |
1011 | { | |
1012 | uschar *new_smtp_port = NULL; | |
1013 | uschar *new_local_interfaces = NULL; | |
1014 | int portsize = 0; | |
1015 | int portptr = 0; | |
1016 | int ifacesize = 0; | |
1017 | int ifaceptr = 0; | |
1018 | ||
1019 | if (override_pid_file_path == NULL) write_pid = FALSE; | |
1020 | ||
1021 | list = override_local_interfaces; | |
1022 | sep = 0; | |
1023 | while ((s = string_nextinlist(&list,&sep,big_buffer,big_buffer_size)) | |
1024 | != NULL) | |
1025 | { | |
1026 | uschar joinstr[4]; | |
1027 | uschar **ptr; | |
1028 | int *sizeptr; | |
1029 | int *ptrptr; | |
1030 | ||
1031 | if (Ustrpbrk(s, ".:") == NULL) | |
1032 | { | |
1033 | ptr = &new_smtp_port; | |
1034 | sizeptr = &portsize; | |
1035 | ptrptr = &portptr; | |
1036 | } | |
1037 | else | |
1038 | { | |
1039 | ptr = &new_local_interfaces; | |
1040 | sizeptr = &ifacesize; | |
1041 | ptrptr = &ifaceptr; | |
1042 | } | |
1043 | ||
1044 | if (*ptr == NULL) | |
1045 | { | |
1046 | joinstr[0] = sep; | |
1047 | joinstr[1] = ' '; | |
1048 | *ptr = string_cat(*ptr, sizeptr, ptrptr, US"<", 1); | |
1049 | } | |
1050 | ||
1051 | *ptr = string_cat(*ptr, sizeptr, ptrptr, joinstr, 2); | |
1052 | *ptr = string_cat(*ptr, sizeptr, ptrptr, s, Ustrlen(s)); | |
1053 | } | |
1054 | ||
1055 | if (new_smtp_port != NULL) | |
1056 | { | |
1057 | new_smtp_port[portptr] = 0; | |
1058 | daemon_smtp_port = new_smtp_port; | |
1059 | DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n", | |
1060 | daemon_smtp_port); | |
1061 | } | |
1062 | ||
1063 | if (new_local_interfaces != NULL) | |
1064 | { | |
1065 | new_local_interfaces[ifaceptr] = 0; | |
1066 | local_interfaces = new_local_interfaces; | |
1067 | local_iface_source = US"-oX data"; | |
1068 | DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n", | |
1069 | local_interfaces); | |
1070 | } | |
1071 | } | |
1072 | ||
1073 | /* Create a list of default SMTP ports, to be used if local_interfaces | |
1074 | contains entries without explict ports. First count the number of ports, then | |
1075 | build a translated list in a vector. */ | |
1076 | ||
1077 | list = daemon_smtp_port; | |
1078 | sep = 0; | |
1079 | while ((s = string_nextinlist(&list,&sep,big_buffer,big_buffer_size)) != NULL) | |
1080 | pct++; | |
1081 | default_smtp_port = store_get((pct+1) * sizeof(int)); | |
1082 | list = daemon_smtp_port; | |
1083 | sep = 0; | |
1084 | for (pct = 0; | |
1085 | (s = string_nextinlist(&list,&sep,big_buffer,big_buffer_size)) != NULL; | |
1086 | pct++) | |
1087 | { | |
1088 | if (isdigit(*s)) | |
1089 | { | |
1090 | uschar *end; | |
1091 | default_smtp_port[pct] = Ustrtol(s, &end, 0); | |
1092 | if (end != s + Ustrlen(s)) | |
1093 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s); | |
1094 | } | |
1095 | else | |
1096 | { | |
1097 | struct servent *smtp_service = getservbyname(CS s, "tcp"); | |
1098 | if (smtp_service == NULL) | |
1099 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s); | |
1100 | default_smtp_port[pct] = ntohs(smtp_service->s_port); | |
1101 | } | |
1102 | } | |
1103 | default_smtp_port[pct] = 0; | |
1104 | ||
1105 | /* Create the list of local interfaces, possibly with ports included. This | |
1106 | list may contain references to 0.0.0.0 and ::0 as wildcards. These special | |
1107 | values are converted below. */ | |
1108 | ||
1109 | addresses = host_build_ifacelist(local_interfaces, local_iface_source); | |
1110 | ||
1111 | /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0 | |
1112 | into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In | |
1113 | fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards | |
1114 | anyway, but we need to know which are the wildcard addresses, and the shorter | |
1115 | strings are neater. | |
1116 | ||
1117 | In the same scan, fill in missing port numbers from the default list. When | |
1118 | there is more than one item in the list, extra items are created. */ | |
1119 | ||
1120 | for (ipa = addresses; ipa != NULL; ipa = ipa->next) | |
1121 | { | |
1122 | int i; | |
1123 | ||
1124 | if (Ustrcmp(ipa->address, "0.0.0.0") == 0) ipa->address[0] = 0; | |
1125 | else if (Ustrcmp(ipa->address, "::0") == 0) | |
1126 | { | |
1127 | ipa->address[0] = ':'; | |
1128 | ipa->address[1] = 0; | |
1129 | } | |
1130 | ||
1131 | if (ipa->port > 0) continue; | |
1132 | ||
1133 | if (daemon_smtp_port[0] <= 0) | |
1134 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface " | |
1135 | "%s and daemon_smtp_port is unset; cannot start daemon", | |
1136 | (ipa->address[0] == 0)? US"\"all IPv4\"" : | |
1137 | (ipa->address[1] == 0)? US"\"all IPv6\"" : ipa->address); | |
1138 | ipa->port = default_smtp_port[0]; | |
1139 | for (i = 1; default_smtp_port[i] > 0; i++) | |
1140 | { | |
1141 | ip_address_item *new = store_get(sizeof(ip_address_item)); | |
1142 | memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1); | |
1143 | new->port = default_smtp_port[i]; | |
1144 | new->next = ipa->next; | |
1145 | ipa->next = new; | |
1146 | ipa = new; | |
1147 | } | |
1148 | } | |
1149 | ||
1150 | /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6 | |
1151 | wildcard for the same port, ensure that (a) they are together and (b) the | |
1152 | IPv6 address comes first. This makes handling the messy features easier, and | |
1153 | also simplifies the construction of the "daemon started" log line. */ | |
1154 | ||
1155 | pipa = &addresses; | |
1156 | for (ipa = addresses; ipa != NULL; pipa = &(ipa->next), ipa = ipa->next) | |
1157 | { | |
1158 | ip_address_item *ipa2; | |
1159 | ||
1160 | /* Handle an IPv4 wildcard */ | |
1161 | ||
1162 | if (ipa->address[0] == 0) | |
1163 | { | |
1164 | for (ipa2 = ipa; ipa2->next != NULL; ipa2 = ipa2->next) | |
1165 | { | |
1166 | ip_address_item *ipa3 = ipa2->next; | |
1167 | if (ipa3->address[0] == ':' && | |
1168 | ipa3->address[1] == 0 && | |
1169 | ipa3->port == ipa->port) | |
1170 | { | |
1171 | ipa2->next = ipa3->next; | |
1172 | ipa3->next = ipa; | |
1173 | *pipa = ipa3; | |
1174 | break; | |
1175 | } | |
1176 | } | |
1177 | } | |
1178 | ||
1179 | /* Handle an IPv6 wildcard. */ | |
1180 | ||
1181 | else if (ipa->address[0] == ':' && ipa->address[1] == 0) | |
1182 | { | |
1183 | for (ipa2 = ipa; ipa2->next != NULL; ipa2 = ipa2->next) | |
1184 | { | |
1185 | ip_address_item *ipa3 = ipa2->next; | |
1186 | if (ipa3->address[0] == 0 && ipa3->port == ipa->port) | |
1187 | { | |
1188 | ipa2->next = ipa3->next; | |
1189 | ipa3->next = ipa->next; | |
1190 | ipa->next = ipa3; | |
1191 | ipa = ipa3; | |
1192 | break; | |
1193 | } | |
1194 | } | |
1195 | } | |
1196 | } | |
1197 | ||
1198 | /* Get a vector to remember all the sockets in */ | |
1199 | ||
1200 | for (ipa = addresses; ipa != NULL; ipa = ipa->next) | |
1201 | listen_socket_count++; | |
1202 | listen_sockets = store_get(sizeof(int *) * listen_socket_count); | |
1203 | ||
1204 | /* Do a sanity check on the max connects value just to save us from getting | |
1205 | a huge amount of store. */ | |
1206 | ||
1207 | if (smtp_accept_max > 4095) smtp_accept_max = 4096; | |
1208 | ||
1209 | /* There's no point setting smtp_accept_queue unless it is less than the max | |
1210 | connects limit. The configuration reader ensures that the max is set if the | |
1211 | queue-only option is set. */ | |
1212 | ||
1213 | if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0; | |
1214 | ||
1215 | /* Get somewhere to keep the list of SMTP accepting pids if we are keeping | |
1216 | track of them for total number and queue/host limits. */ | |
1217 | ||
1218 | if (smtp_accept_max > 0) | |
1219 | { | |
1220 | int i; | |
1221 | smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot)); | |
1222 | for (i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot; | |
1223 | } | |
1224 | } | |
1225 | ||
76a2d7ba PH |
1226 | /* The variable background_daemon is always false when debugging, but |
1227 | can also be forced false in order to keep a non-debugging daemon in the | |
1228 | foreground. If background_daemon is true, close all open file descriptors that | |
1229 | we know about, but then re-open stdin, stdout, and stderr to /dev/null. | |
1230 | ||
1231 | This is protection against any called functions (in libraries, or in | |
1232 | Perl, or whatever) that think they can write to stderr (or stdout). Before this | |
1233 | was added, it was quite likely that an SMTP connection would use one of these | |
1234 | file descriptors, in which case writing random stuff to it caused chaos. | |
1235 | ||
1236 | Then disconnect from the controlling terminal, Most modern Unixes seem to have | |
1237 | setsid() for getting rid of the controlling terminal. For any OS that doesn't, | |
1238 | setsid() can be #defined as a no-op, or as something else. */ | |
059ec3d9 PH |
1239 | |
1240 | if (background_daemon) | |
1241 | { | |
76a2d7ba PH |
1242 | log_close_all(); /* Just in case anything was logged earlier */ |
1243 | search_tidyup(); /* Just in case any were used in reading the config. */ | |
f1e894f3 PH |
1244 | (void)close(0); /* Get rid of stdin/stdout/stderr */ |
1245 | (void)close(1); | |
1246 | (void)close(2); | |
8e669ac1 | 1247 | exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */ |
059ec3d9 PH |
1248 | log_stderr = NULL; /* So no attempt to copy paniclog output */ |
1249 | ||
1250 | /* If the parent process of this one has pid == 1, we are re-initializing the | |
8e669ac1 | 1251 | daemon as the result of a SIGHUP. In this case, there is no need to do |
76a2d7ba PH |
1252 | anything, because the controlling terminal has long gone. Otherwise, fork, in |
1253 | case current process is a process group leader (see 'man setsid' for an | |
1254 | explanation) before calling setsid(). */ | |
059ec3d9 PH |
1255 | |
1256 | if (getppid() != 1) | |
1257 | { | |
1258 | pid_t pid = fork(); | |
1259 | if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, | |
1260 | "fork() failed when starting daemon: %s", strerror(errno)); | |
1261 | if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */ | |
1262 | (void)setsid(); /* release controlling terminal */ | |
1263 | } | |
1264 | } | |
1265 | ||
1266 | /* We are now in the disconnected, daemon process (unless debugging). Set up | |
1267 | the listening sockets if required. */ | |
1268 | ||
1269 | if (daemon_listen) | |
1270 | { | |
1271 | int sk; | |
1272 | int on = 1; | |
1273 | ip_address_item *ipa; | |
1274 | ||
1275 | /* For each IP address, create a socket, bind it to the appropriate port, and | |
1276 | start listening. See comments above about IPv6 sockets that may or may not | |
1277 | accept IPv4 calls when listening on all interfaces. We also have to cope with | |
1278 | the case of a system with IPv6 libraries, but no IPv6 support in the kernel. | |
1279 | listening, provided a wildcard IPv4 socket for the same port follows. */ | |
1280 | ||
1281 | for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++) | |
1282 | { | |
1283 | BOOL wildcard; | |
1284 | ip_address_item *ipa2; | |
059ec3d9 PH |
1285 | int af; |
1286 | ||
1287 | if (Ustrchr(ipa->address, ':') != NULL) | |
1288 | { | |
1289 | af = AF_INET6; | |
1290 | wildcard = ipa->address[1] == 0; | |
1291 | } | |
1292 | else | |
1293 | { | |
1294 | af = AF_INET; | |
1295 | wildcard = ipa->address[0] == 0; | |
1296 | } | |
1297 | ||
1298 | listen_sockets[sk] = ip_socket(SOCK_STREAM, af); | |
1299 | if (listen_sockets[sk] < 0) | |
1300 | { | |
1301 | if (check_special_case(0, addresses, ipa, FALSE)) | |
1302 | { | |
1303 | log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard " | |
1304 | "listening (%s): will use IPv4", strerror(errno)); | |
1305 | goto SKIP_SOCKET; | |
1306 | } | |
1307 | log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s", | |
1308 | (af == AF_INET6)? '6' : '4', strerror(errno)); | |
1309 | } | |
1310 | ||
1311 | /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is | |
1312 | available. Just log failure (can get protocol not available, just like | |
1313 | socket creation can). */ | |
1314 | ||
1315 | #ifdef IPV6_V6ONLY | |
1316 | if (af == AF_INET6 && wildcard && | |
1317 | setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, (char *)(&on), | |
1318 | sizeof(on)) < 0) | |
1319 | log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard " | |
1320 | "socket failed (%s): carrying on without it", strerror(errno)); | |
1321 | #endif /* IPV6_V6ONLY */ | |
1322 | ||
1323 | /* Set SO_REUSEADDR so that the daemon can be restarted while a connection | |
1324 | is being handled. Without this, a connection will prevent reuse of the | |
1325 | smtp port for listening. */ | |
1326 | ||
1327 | if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR, | |
1328 | (uschar *)(&on), sizeof(on)) < 0) | |
1329 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket " | |
1330 | "failed when starting daemon: %s", strerror(errno)); | |
1331 | ||
1332 | /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to | |
1333 | disable this because it breaks some broken clients. */ | |
1334 | ||
1335 | if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY, | |
1336 | (uschar *)(&on), sizeof(on)); | |
1337 | ||
1338 | /* Now bind the socket to the required port; if Exim is being restarted | |
1339 | it may not always be possible to bind immediately, even with SO_REUSEADDR | |
1340 | set, so try 10 times, waiting between each try. After 10 failures, we give | |
1341 | up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and | |
1342 | we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard | |
1343 | address for the same port, ignore the error on the grounds that we must be | |
1344 | in a system where the IPv6 socket accepts both kinds of call. This is | |
1345 | necessary for (some release of) USAGI Linux; other IP stacks fail at the | |
1346 | listen() stage instead. */ | |
1347 | ||
1348 | for(;;) | |
1349 | { | |
1350 | uschar *msg, *addr; | |
1351 | if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break; | |
1352 | if (check_special_case(errno, addresses, ipa, TRUE)) | |
1353 | { | |
1354 | DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 " | |
1355 | "listen() success; EADDRINUSE ignored\n"); | |
f1e894f3 | 1356 | (void)close(listen_sockets[sk]); |
059ec3d9 PH |
1357 | goto SKIP_SOCKET; |
1358 | } | |
1359 | msg = US strerror(errno); | |
1360 | addr = wildcard? ((af == AF_INET6)? US"(any IPv6)" : US"(any IPv4)") : | |
1361 | ipa->address; | |
4aee0225 | 1362 | if (daemon_startup_retries <= 0) |
059ec3d9 PH |
1363 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, |
1364 | "socket bind() to port %d for address %s failed: %s: " | |
1365 | "daemon abandoned", ipa->port, addr, msg); | |
1366 | log_write(0, LOG_MAIN, "socket bind() to port %d for address %s " | |
4aee0225 PH |
1367 | "failed: %s: waiting %s before trying again (%d more %s)", |
1368 | ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep), | |
1369 | daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try"); | |
1370 | daemon_startup_retries--; | |
1371 | sleep(daemon_startup_sleep); | |
059ec3d9 PH |
1372 | } |
1373 | ||
1374 | DEBUG(D_any) | |
1375 | { | |
1376 | if (wildcard) | |
1377 | debug_printf("listening on all interfaces (IPv%c) port %d\n", | |
1378 | (af == AF_INET6)? '6' : '4', ipa->port); | |
1379 | else | |
1380 | debug_printf("listening on %s port %d\n", ipa->address, ipa->port); | |
1381 | } | |
1382 | ||
1383 | /* Start listening on the bound socket, establishing the maximum backlog of | |
1384 | connections that is allowed. On success, continue to the next address. */ | |
1385 | ||
1386 | if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0) continue; | |
1387 | ||
1388 | /* Listening has failed. In an IPv6 environment, as for bind(), if listen() | |
1389 | fails with the error EADDRINUSE and we are doing IPv4 wildcard listening | |
1390 | and there was a previous successful IPv6 wildcard listen on the same port, | |
1391 | we want to ignore the error on the grounds that we must be in a system | |
1392 | where the IPv6 socket accepts both kinds of call. */ | |
1393 | ||
1394 | if (!check_special_case(errno, addresses, ipa, TRUE)) | |
1395 | log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s", | |
1396 | wildcard? ((af == AF_INET6)? US"(any IPv6)" : US"(any IPv4)") : | |
1397 | ipa->address, | |
1398 | strerror(errno)); | |
1399 | ||
1400 | DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 " | |
1401 | "listen() success; EADDRINUSE ignored\n"); | |
f1e894f3 | 1402 | (void)close(listen_sockets[sk]); |
059ec3d9 PH |
1403 | |
1404 | /* Come here if there has been a problem with the socket which we | |
1405 | are going to ignore. We remove the address from the chain, and back up the | |
1406 | counts. */ | |
1407 | ||
1408 | SKIP_SOCKET: | |
1409 | sk--; /* Back up the count */ | |
1410 | listen_socket_count--; /* Reduce the total */ | |
1411 | if (ipa == addresses) addresses = ipa->next; else | |
1412 | { | |
1413 | for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next); | |
1414 | ipa2->next = ipa->next; | |
1415 | ipa = ipa2; | |
1416 | } | |
1417 | } /* End of bind/listen loop for each address */ | |
1418 | } /* End of setup for listening */ | |
1419 | ||
1420 | ||
1421 | /* If we are not listening, we want to write a pid file only if -oP was | |
1422 | explicitly given. */ | |
1423 | ||
1424 | else if (override_pid_file_path == NULL) write_pid = FALSE; | |
1425 | ||
1426 | /* Write the pid to a known file for assistance in identification, if required. | |
1427 | We do this before giving up root privilege, because on some systems it is | |
1428 | necessary to be root in order to write into the pid file directory. There's | |
1429 | nothing to stop multiple daemons running, as long as no more than one listens | |
1430 | on a given TCP/IP port on the same interface(s). However, in these | |
1431 | circumstances it gets far too complicated to mess with pid file names | |
1432 | automatically. Consequently, Exim 4 writes a pid file only | |
1433 | ||
1434 | (a) When running in the test harness, or | |
1435 | (b) When -bd is used and -oX is not used, or | |
1436 | (c) When -oP is used to supply a path. | |
1437 | ||
1438 | The variable daemon_write_pid is used to control this. */ | |
1439 | ||
1440 | if (running_in_test_harness || write_pid) | |
1441 | { | |
1442 | FILE *f; | |
1443 | ||
1444 | if (override_pid_file_path != NULL) | |
1445 | pid_file_path = override_pid_file_path; | |
1446 | ||
1447 | if (pid_file_path[0] == 0) | |
1448 | pid_file_path = string_sprintf("%s/exim-daemon.pid", spool_directory); | |
1449 | ||
2632889e | 1450 | f = modefopen(pid_file_path, "wb", 0644); |
059ec3d9 PH |
1451 | if (f != NULL) |
1452 | { | |
ff790e47 | 1453 | (void)fprintf(f, "%d\n", (int)getpid()); |
ff790e47 | 1454 | (void)fclose(f); |
059ec3d9 PH |
1455 | DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path); |
1456 | } | |
1457 | else | |
1458 | { | |
1459 | DEBUG(D_any) | |
1460 | debug_printf("%s\n", string_open_failed(errno, "pid file %s", | |
1461 | pid_file_path)); | |
1462 | } | |
1463 | } | |
1464 | ||
1465 | /* Set up the handler for SIGHUP, which causes a restart of the daemon. */ | |
1466 | ||
1467 | sighup_seen = FALSE; | |
1468 | signal(SIGHUP, sighup_handler); | |
1469 | ||
1470 | /* Give up root privilege at this point (assuming that exim_uid and exim_gid | |
1471 | are not root). The third argument controls the running of initgroups(). | |
1472 | Normally we do this, in order to set up the groups for the Exim user. However, | |
1473 | if we are not root at this time - some odd installations run that way - we | |
1474 | cannot do this. */ | |
1475 | ||
1476 | exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon"); | |
1477 | ||
ebeaf996 PH |
1478 | /* Update the originator_xxx fields so that received messages as listed as |
1479 | coming from Exim, not whoever started the daemon. */ | |
1480 | ||
1481 | originator_uid = exim_uid; | |
1482 | originator_gid = exim_gid; | |
1483 | originator_login = ((pw = getpwuid(exim_uid)) != NULL)? | |
1484 | string_copy_malloc(US pw->pw_name) : US"exim"; | |
1485 | ||
059ec3d9 PH |
1486 | /* Get somewhere to keep the list of queue-runner pids if we are keeping track |
1487 | of them (and also if we are doing queue runs). */ | |
1488 | ||
1489 | if (queue_interval > 0 && queue_run_max > 0) | |
1490 | { | |
1491 | int i; | |
1492 | queue_pid_slots = store_get(queue_run_max * sizeof(pid_t)); | |
1493 | for (i = 0; i < queue_run_max; i++) queue_pid_slots[i] = 0; | |
1494 | } | |
1495 | ||
1496 | /* Set up the handler for termination of child processes. */ | |
1497 | ||
1498 | sigchld_seen = FALSE; | |
7d468ab8 | 1499 | os_non_restarting_signal(SIGCHLD, main_sigchld_handler); |
059ec3d9 PH |
1500 | |
1501 | /* If we are to run the queue periodically, pretend the alarm has just gone | |
1502 | off. This will cause the first queue-runner to get kicked off straight away. */ | |
1503 | ||
1504 | sigalrm_seen = (queue_interval > 0); | |
1505 | ||
1506 | /* Log the start up of a daemon - at least one of listening or queue running | |
1507 | must be set up. */ | |
1508 | ||
1509 | if (daemon_listen) | |
1510 | { | |
1511 | int i, j; | |
1512 | int smtp_ports = 0; | |
1513 | int smtps_ports = 0; | |
1514 | ip_address_item *ipa; | |
1515 | uschar *p = big_buffer; | |
1516 | uschar *qinfo = (queue_interval > 0)? | |
1517 | string_sprintf("-q%s", readconf_printtime(queue_interval)) | |
1518 | : | |
1519 | US"no queue runs"; | |
1520 | ||
1521 | /* Build a list of listening addresses in big_buffer, but limit it to 10 | |
1522 | items. The style is for backwards compatibility. | |
1523 | ||
1524 | It is now possible to have some ports listening for SMTPS (the old, | |
1525 | deprecated protocol that starts TLS without using STARTTLS), and others | |
1526 | listening for standard SMTP. Keep their listings separate. */ | |
1527 | ||
1528 | for (j = 0; j < 2; j++) | |
1529 | { | |
1530 | for (i = 0, ipa = addresses; i < 10 && ipa != NULL; i++, ipa = ipa->next) | |
1531 | { | |
1532 | /* First time round, look for SMTP ports; second time round, look for | |
1533 | SMTPS ports. For the first one of each, insert leading text. */ | |
1534 | ||
1535 | if (host_is_tls_on_connect_port(ipa->port) == (j > 0)) | |
1536 | { | |
1537 | if (j == 0) | |
1538 | { | |
1539 | if (smtp_ports++ == 0) | |
1540 | { | |
1541 | memcpy(p, "SMTP on", 8); | |
1542 | p += 7; | |
1543 | } | |
1544 | } | |
1545 | else | |
1546 | { | |
1547 | if (smtps_ports++ == 0) | |
1548 | { | |
1549 | (void)sprintf(CS p, "%sSMTPS on", | |
1550 | (smtp_ports == 0)? "":" and for "); | |
1551 | while (*p != 0) p++; | |
1552 | } | |
1553 | } | |
1554 | ||
1555 | /* Now the information about the port (and sometimes interface) */ | |
1556 | ||
1557 | if (ipa->address[0] == ':' && ipa->address[1] == 0) | |
1558 | { | |
1559 | if (ipa->next != NULL && ipa->next->address[0] == 0 && | |
1560 | ipa->next->port == ipa->port) | |
1561 | { | |
1562 | (void)sprintf(CS p, " port %d (IPv6 and IPv4)", ipa->port); | |
1563 | ipa = ipa->next; | |
1564 | } | |
1565 | else if (ipa->v6_include_v4) | |
1566 | (void)sprintf(CS p, " port %d (IPv6 with IPv4)", ipa->port); | |
1567 | else | |
1568 | (void)sprintf(CS p, " port %d (IPv6)", ipa->port); | |
1569 | } | |
1570 | else if (ipa->address[0] == 0) | |
1571 | (void)sprintf(CS p, " port %d (IPv4)", ipa->port); | |
1572 | else | |
1573 | (void)sprintf(CS p, " [%s]:%d", ipa->address, ipa->port); | |
1574 | while (*p != 0) p++; | |
1575 | } | |
1576 | } | |
1577 | ||
1578 | if (ipa != NULL) | |
1579 | { | |
1580 | memcpy(p, " ...", 5); | |
1581 | p += 4; | |
1582 | } | |
1583 | } | |
1584 | ||
1585 | log_write(0, LOG_MAIN, | |
1586 | "exim %s daemon started: pid=%d, %s, listening for %s", | |
1587 | version_string, getpid(), qinfo, big_buffer); | |
1588 | set_process_info("daemon: %s, listening for %s", qinfo, big_buffer); | |
1589 | } | |
1590 | ||
1591 | else | |
1592 | { | |
1593 | log_write(0, LOG_MAIN, | |
1594 | "exim %s daemon started: pid=%d, -q%s, not listening for SMTP", | |
1595 | version_string, getpid(), readconf_printtime(queue_interval)); | |
1596 | set_process_info("daemon: -q%s, not listening", | |
1597 | readconf_printtime(queue_interval)); | |
1598 | } | |
1599 | ||
1600 | ||
1601 | /* Close the log so it can be renamed and moved. In the few cases below where | |
1602 | this long-running process writes to the log (always exceptional conditions), it | |
1603 | closes the log afterwards, for the same reason. */ | |
1604 | ||
1605 | log_close_all(); | |
1606 | ||
1607 | DEBUG(D_any) debug_print_ids(US"daemon running with"); | |
1608 | ||
1609 | /* Any messages accepted via this route are going to be SMTP. */ | |
1610 | ||
1611 | smtp_input = TRUE; | |
1612 | ||
1613 | /* Enter the never-ending loop... */ | |
1614 | ||
1615 | for (;;) | |
1616 | { | |
1617 | #if HAVE_IPV6 | |
1618 | struct sockaddr_in6 accepted; | |
1619 | #else | |
1620 | struct sockaddr_in accepted; | |
1621 | #endif | |
1622 | ||
cf73943b | 1623 | EXIM_SOCKLEN_T len; |
059ec3d9 PH |
1624 | pid_t pid; |
1625 | ||
1626 | /* This code is placed first in the loop, so that it gets obeyed at the | |
1627 | start, before the first wait. This causes the first queue-runner to be | |
1628 | started immediately. */ | |
1629 | ||
1630 | if (sigalrm_seen) | |
1631 | { | |
1632 | DEBUG(D_any) debug_printf("SIGALRM received\n"); | |
1633 | ||
1634 | /* Do a full queue run in a child process, if required, unless we already | |
1635 | have enough queue runners on the go. If we are not running as root, a | |
1636 | re-exec is required. */ | |
1637 | ||
1638 | if (queue_interval > 0 && | |
1639 | (queue_run_max <= 0 || queue_run_count < queue_run_max)) | |
1640 | { | |
1641 | if ((pid = fork()) == 0) | |
1642 | { | |
1643 | int sk; | |
8e669ac1 | 1644 | |
059ec3d9 PH |
1645 | DEBUG(D_any) debug_printf("Starting queue-runner: pid %d\n", |
1646 | (int)getpid()); | |
1647 | ||
3d235903 | 1648 | /* Disable debugging if it's required only for the daemon process. We |
8e669ac1 | 1649 | leave the above message, because it ties up with the "child ended" |
3d235903 PH |
1650 | debugging messages. */ |
1651 | ||
1652 | if (debug_daemon) debug_selector = 0; | |
8e669ac1 | 1653 | |
059ec3d9 PH |
1654 | /* Close any open listening sockets in the child */ |
1655 | ||
f1e894f3 PH |
1656 | for (sk = 0; sk < listen_socket_count; sk++) |
1657 | (void)close(listen_sockets[sk]); | |
059ec3d9 PH |
1658 | |
1659 | /* Reset SIGHUP and SIGCHLD in the child in both cases. */ | |
1660 | ||
1661 | signal(SIGHUP, SIG_DFL); | |
1662 | signal(SIGCHLD, SIG_DFL); | |
1663 | ||
1664 | /* Re-exec if privilege has been given up, unless deliver_drop_ | |
1665 | privilege is set. Reset SIGALRM before exec(). */ | |
1666 | ||
1667 | if (geteuid() != root_uid && !deliver_drop_privilege) | |
1668 | { | |
1669 | uschar opt[8]; | |
1670 | uschar *p = opt; | |
5f16ca82 | 1671 | uschar *extra[5]; |
4fbcfc2e | 1672 | int extracount = 1; |
059ec3d9 PH |
1673 | |
1674 | signal(SIGALRM, SIG_DFL); | |
1675 | *p++ = '-'; | |
1676 | *p++ = 'q'; | |
1677 | if (queue_2stage) *p++ = 'q'; | |
1678 | if (queue_run_first_delivery) *p++ = 'i'; | |
1679 | if (queue_run_force) *p++ = 'f'; | |
1680 | if (deliver_force_thaw) *p++ = 'f'; | |
1681 | if (queue_run_local) *p++ = 'l'; | |
1682 | *p = 0; | |
4fbcfc2e PH |
1683 | extra[0] = opt; |
1684 | ||
1685 | /* If -R or -S were on the original command line, ensure they get | |
1686 | passed on. */ | |
1687 | ||
1688 | if (deliver_selectstring != NULL) | |
1689 | { | |
1690 | extra[extracount++] = deliver_selectstring_regex? US"-Rr" : US"-R"; | |
1691 | extra[extracount++] = deliver_selectstring; | |
1692 | } | |
1693 | ||
1694 | if (deliver_selectstring_sender != NULL) | |
1695 | { | |
1696 | extra[extracount++] = deliver_selectstring_sender_regex? | |
1697 | US"-Sr" : US"-S"; | |
1698 | extra[extracount++] = deliver_selectstring_sender; | |
1699 | } | |
1700 | ||
1701 | /* Overlay this process with a new execution. */ | |
1702 | ||
1703 | (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, TRUE, extracount, | |
1704 | extra[0], extra[1], extra[2], extra[3], extra[4]); | |
059ec3d9 | 1705 | |
059ec3d9 PH |
1706 | /* Control never returns here. */ |
1707 | } | |
1708 | ||
1709 | /* No need to re-exec; SIGALRM remains set to the default handler */ | |
1710 | ||
1711 | queue_run(NULL, NULL, FALSE); | |
1712 | _exit(EXIT_SUCCESS); | |
1713 | } | |
1714 | ||
1715 | if (pid < 0) | |
1716 | { | |
1717 | log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner " | |
1718 | "process failed: %s", strerror(errno)); | |
1719 | log_close_all(); | |
1720 | } | |
1721 | else | |
1722 | { | |
1723 | int i; | |
1724 | for (i = 0; i < queue_run_max; ++i) | |
1725 | { | |
1726 | if (queue_pid_slots[i] <= 0) | |
1727 | { | |
1728 | queue_pid_slots[i] = pid; | |
1729 | queue_run_count++; | |
1730 | break; | |
1731 | } | |
1732 | } | |
1733 | DEBUG(D_any) debug_printf("%d queue-runner process%s running\n", | |
1734 | queue_run_count, (queue_run_count == 1)? "" : "es"); | |
1735 | } | |
1736 | } | |
1737 | ||
1738 | /* Reset the alarm clock */ | |
1739 | ||
1740 | sigalrm_seen = FALSE; | |
1741 | alarm(queue_interval); | |
1742 | } | |
1743 | ||
1744 | ||
1745 | /* Sleep till a connection happens if listening, and handle the connection if | |
1746 | that is why we woke up. The FreeBSD operating system requires the use of | |
1747 | select() before accept() because the latter function is not interrupted by | |
1748 | a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other | |
1749 | OS do notice signals in accept() but it does no harm to have the select() | |
1750 | in for all of them - and it won't then be a lurking problem for ports to | |
1751 | new OS. In fact, the later addition of listening on specific interfaces only | |
1752 | requires this way of working anyway. */ | |
1753 | ||
1754 | if (daemon_listen) | |
1755 | { | |
bb6e88ff | 1756 | int sk, lcount, select_errno; |
059ec3d9 PH |
1757 | int max_socket = 0; |
1758 | BOOL select_failed = FALSE; | |
1759 | fd_set select_listen; | |
1760 | ||
1761 | FD_ZERO(&select_listen); | |
1762 | for (sk = 0; sk < listen_socket_count; sk++) | |
1763 | { | |
1764 | FD_SET(listen_sockets[sk], &select_listen); | |
1765 | if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk]; | |
1766 | } | |
1767 | ||
1768 | DEBUG(D_any) debug_printf("Listening...\n"); | |
8e669ac1 PH |
1769 | |
1770 | /* In rare cases we may have had a SIGCHLD signal in the time between | |
1771 | setting the handler (below) and getting back here. If so, pretend that the | |
7d468ab8 | 1772 | select() was interrupted so that we reap the child. This might still leave |
8e669ac1 | 1773 | a small window when a SIGCHLD could get lost. However, since we use SIGCHLD |
7d468ab8 PH |
1774 | only to do the reaping more quickly, it shouldn't result in anything other |
1775 | than a delay until something else causes a wake-up. */ | |
1776 | ||
1777 | if (sigchld_seen) | |
1778 | { | |
1779 | lcount = -1; | |
8e669ac1 | 1780 | errno = EINTR; |
7d468ab8 PH |
1781 | } |
1782 | else | |
8e669ac1 | 1783 | { |
7d468ab8 PH |
1784 | lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen, |
1785 | NULL, NULL, NULL); | |
8e669ac1 | 1786 | } |
059ec3d9 | 1787 | |
7d468ab8 | 1788 | if (lcount < 0) |
059ec3d9 PH |
1789 | { |
1790 | select_failed = TRUE; | |
1791 | lcount = 1; | |
1792 | } | |
8e669ac1 PH |
1793 | |
1794 | /* Clean up any subprocesses that may have terminated. We need to do this | |
1795 | here so that smtp_accept_max_per_host works when a connection to that host | |
1796 | has completed, and we are about to accept a new one. When this code was | |
1797 | later in the sequence, a new connection could be rejected, even though an | |
1798 | old one had just finished. Preserve the errno from any select() failure for | |
bb6e88ff | 1799 | the use of the common select/accept error processing below. */ |
8e669ac1 | 1800 | |
bb6e88ff PH |
1801 | select_errno = errno; |
1802 | handle_ending_processes(); | |
8e669ac1 PH |
1803 | errno = select_errno; |
1804 | ||
059ec3d9 | 1805 | /* Loop for all the sockets that are currently ready to go. If select |
7d468ab8 PH |
1806 | actually failed, we have set the count to 1 and select_failed=TRUE, so as |
1807 | to use the common error code for select/accept below. */ | |
059ec3d9 PH |
1808 | |
1809 | while (lcount-- > 0) | |
1810 | { | |
1811 | int accept_socket = -1; | |
1812 | if (!select_failed) | |
1813 | { | |
1814 | for (sk = 0; sk < listen_socket_count; sk++) | |
1815 | { | |
1816 | if (FD_ISSET(listen_sockets[sk], &select_listen)) | |
1817 | { | |
cf73943b | 1818 | len = sizeof(accepted); |
059ec3d9 PH |
1819 | accept_socket = accept(listen_sockets[sk], |
1820 | (struct sockaddr *)&accepted, &len); | |
1821 | FD_CLR(listen_sockets[sk], &select_listen); | |
1822 | break; | |
1823 | } | |
1824 | } | |
1825 | } | |
1826 | ||
1827 | /* If select or accept has failed and this was not caused by an | |
1828 | interruption, log the incident and try again. With asymmetric TCP/IP | |
1829 | routing errors such as "No route to network" have been seen here. Also | |
1830 | "connection reset by peer" has been seen. These cannot be classed as | |
1831 | disastrous errors, but they could fill up a lot of log. The code in smail | |
1832 | crashes the daemon after 10 successive failures of accept, on the grounds | |
1833 | that some OS fail continuously. Exim originally followed suit, but this | |
1834 | appears to have caused problems. Now it just keeps going, but instead of | |
1835 | logging each error, it batches them up when they are continuous. */ | |
1836 | ||
1837 | if (accept_socket < 0 && errno != EINTR) | |
1838 | { | |
1839 | if (accept_retry_count == 0) | |
1840 | { | |
1841 | accept_retry_errno = errno; | |
1842 | accept_retry_select_failed = select_failed; | |
1843 | } | |
1844 | else | |
1845 | { | |
1846 | if (errno != accept_retry_errno || | |
1847 | select_failed != accept_retry_select_failed || | |
1848 | accept_retry_count >= 50) | |
1849 | { | |
1850 | log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0), | |
1851 | "%d %s() failure%s: %s", | |
1852 | accept_retry_count, | |
1853 | accept_retry_select_failed? "select" : "accept", | |
1854 | (accept_retry_count == 1)? "" : "s", | |
1855 | strerror(accept_retry_errno)); | |
1856 | log_close_all(); | |
1857 | accept_retry_count = 0; | |
1858 | accept_retry_errno = errno; | |
1859 | accept_retry_select_failed = select_failed; | |
1860 | } | |
1861 | } | |
1862 | accept_retry_count++; | |
1863 | } | |
1864 | ||
1865 | else | |
1866 | { | |
1867 | if (accept_retry_count > 0) | |
1868 | { | |
1869 | log_write(0, LOG_MAIN, "%d %s() failure%s: %s", | |
1870 | accept_retry_count, | |
1871 | accept_retry_select_failed? "select" : "accept", | |
1872 | (accept_retry_count == 1)? "" : "s", | |
1873 | strerror(accept_retry_errno)); | |
1874 | log_close_all(); | |
1875 | accept_retry_count = 0; | |
1876 | } | |
1877 | } | |
1878 | ||
1879 | /* If select/accept succeeded, deal with the connection. */ | |
1880 | ||
1881 | if (accept_socket >= 0) | |
1882 | handle_smtp_call(listen_sockets, listen_socket_count, accept_socket, | |
1883 | (struct sockaddr *)&accepted); | |
1884 | } | |
1885 | } | |
1886 | ||
1887 | /* If not listening, then just sleep for the queue interval. If we woke | |
1888 | up early the last time for some other signal, it won't matter because | |
1889 | the alarm signal will wake at the right time. This code originally used | |
1890 | sleep() but it turns out that on the FreeBSD system, sleep() is not inter- | |
1891 | rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily | |
1892 | select() can be used as an interruptible sleep() on all versions of Unix. */ | |
1893 | ||
1894 | else | |
1895 | { | |
1896 | struct timeval tv; | |
1897 | tv.tv_sec = queue_interval; | |
1898 | tv.tv_usec = 0; | |
1899 | select(0, NULL, NULL, NULL, &tv); | |
8e669ac1 | 1900 | handle_ending_processes(); |
059ec3d9 PH |
1901 | } |
1902 | ||
1903 | /* Re-enable the SIGCHLD handler if it has been run. It can't do it | |
1904 | for itself, because it isn't doing the waiting itself. */ | |
1905 | ||
1906 | if (sigchld_seen) | |
1907 | { | |
1908 | sigchld_seen = FALSE; | |
7d468ab8 | 1909 | os_non_restarting_signal(SIGCHLD, main_sigchld_handler); |
059ec3d9 PH |
1910 | } |
1911 | ||
1912 | /* Handle being woken by SIGHUP. We know at this point that the result | |
1913 | of accept() has been dealt with, so we can re-exec exim safely, first | |
1914 | closing the listening sockets so that they can be reused. Cancel any pending | |
1915 | alarm in case it is just about to go off, and set SIGHUP to be ignored so | |
1916 | that another HUP in quick succession doesn't clobber the new daemon before it | |
1917 | gets going. All log files get closed by the close-on-exec flag; however, if | |
1918 | the exec fails, we need to close the logs. */ | |
1919 | ||
1920 | if (sighup_seen) | |
1921 | { | |
1922 | int sk; | |
1923 | log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon", | |
1924 | getpid()); | |
f1e894f3 PH |
1925 | for (sk = 0; sk < listen_socket_count; sk++) |
1926 | (void)close(listen_sockets[sk]); | |
059ec3d9 PH |
1927 | alarm(0); |
1928 | signal(SIGHUP, SIG_IGN); | |
1929 | sighup_argv[0] = exim_path; | |
1930 | exim_nullstd(); | |
1931 | execv(CS exim_path, (char *const *)sighup_argv); | |
1932 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s", | |
1933 | getpid(), exim_path, strerror(errno)); | |
1934 | log_close_all(); | |
1935 | } | |
1936 | ||
1937 | } /* End of main loop */ | |
1938 | ||
1939 | /* Control never reaches here */ | |
1940 | } | |
1941 | ||
1942 | /* End of exim_daemon.c */ | |
1943 |