Support service names for tls_on_connect_ports. Bug 72
[exim.git] / src / src / daemon.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2014 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Functions concerned with running Exim as a daemon */
9
10
11 #include "exim.h"
12
13
14 /* Structure for holding data for each SMTP connection */
15
16 typedef struct smtp_slot {
17 pid_t pid; /* pid of the spawned reception process */
18 uschar *host_address; /* address of the client host */
19 } smtp_slot;
20
21 /* An empty slot for initializing (Standard C does not allow constructor
22 expressions in assigments except as initializers in declarations). */
23
24 static smtp_slot empty_smtp_slot = { 0, NULL };
25
26
27
28 /*************************************************
29 * Local static variables *
30 *************************************************/
31
32 static SIGNAL_BOOL sigchld_seen;
33 static SIGNAL_BOOL sighup_seen;
34
35 static int accept_retry_count = 0;
36 static int accept_retry_errno;
37 static BOOL accept_retry_select_failed;
38
39 static int queue_run_count = 0;
40 static pid_t *queue_pid_slots = NULL;
41 static smtp_slot *smtp_slots = NULL;
42
43 static BOOL write_pid = TRUE;
44
45
46
47 /*************************************************
48 * SIGHUP Handler *
49 *************************************************/
50
51 /* All this handler does is to set a flag and re-enable the signal.
52
53 Argument: the signal number
54 Returns: nothing
55 */
56
57 static void
58 sighup_handler(int sig)
59 {
60 sig = sig; /* Keep picky compilers happy */
61 sighup_seen = TRUE;
62 signal(SIGHUP, sighup_handler);
63 }
64
65
66
67 /*************************************************
68 * SIGCHLD handler for main daemon process *
69 *************************************************/
70
71 /* Don't re-enable the handler here, since we aren't doing the
72 waiting here. If the signal is re-enabled, there will just be an
73 infinite sequence of calls to this handler. The SIGCHLD signal is
74 used just as a means of waking up the daemon so that it notices
75 terminated subprocesses as soon as possible.
76
77 Argument: the signal number
78 Returns: nothing
79 */
80
81 static void
82 main_sigchld_handler(int sig)
83 {
84 sig = sig; /* Keep picky compilers happy */
85 os_non_restarting_signal(SIGCHLD, SIG_DFL);
86 sigchld_seen = TRUE;
87 }
88
89
90
91
92 /*************************************************
93 * Unexpected errors in SMTP calls *
94 *************************************************/
95
96 /* This function just saves a bit of repetitious coding.
97
98 Arguments:
99 log_msg Text of message to be logged
100 smtp_msg Text of SMTP error message
101 was_errno The failing errno
102
103 Returns: nothing
104 */
105
106 static void
107 never_error(uschar *log_msg, uschar *smtp_msg, int was_errno)
108 {
109 uschar *emsg = (was_errno <= 0)? US"" :
110 string_sprintf(": %s", strerror(was_errno));
111 log_write(0, LOG_MAIN|LOG_PANIC, "%s%s", log_msg, emsg);
112 if (smtp_out != NULL) smtp_printf("421 %s\r\n", smtp_msg);
113 }
114
115
116
117
118 /*************************************************
119 * Handle a connected SMTP call *
120 *************************************************/
121
122 /* This function is called when an SMTP connection has been accepted.
123 If there are too many, give an error message and close down. Otherwise
124 spin off a sub-process to handle the call. The list of listening sockets
125 is required so that they can be closed in the sub-process. Take care not to
126 leak store in this process - reset the stacking pool at the end.
127
128 Arguments:
129 listen_sockets sockets which are listening for incoming calls
130 listen_socket_count count of listening sockets
131 accept_socket socket of the current accepted call
132 accepted socket information about the current call
133
134 Returns: nothing
135 */
136
137 static void
138 handle_smtp_call(int *listen_sockets, int listen_socket_count,
139 int accept_socket, struct sockaddr *accepted)
140 {
141 pid_t pid;
142 union sockaddr_46 interface_sockaddr;
143 EXIM_SOCKLEN_T ifsize = sizeof(interface_sockaddr);
144 int dup_accept_socket = -1;
145 int max_for_this_host = 0;
146 int wfsize = 0;
147 int wfptr = 0;
148 int use_log_write_selector = log_write_selector;
149 uschar *whofrom = NULL;
150
151 void *reset_point = store_get(0);
152
153 /* Make the address available in ASCII representation, and also fish out
154 the remote port. */
155
156 sender_host_address = host_ntoa(-1, accepted, NULL, &sender_host_port);
157 DEBUG(D_any) debug_printf("Connection request from %s port %d\n",
158 sender_host_address, sender_host_port);
159
160 /* Set up the output stream, check the socket has duplicated, and set up the
161 input stream. These operations fail only the exceptional circumstances. Note
162 that never_error() won't use smtp_out if it is NULL. */
163
164 smtp_out = fdopen(accept_socket, "wb");
165 if (smtp_out == NULL)
166 {
167 never_error(US"daemon: fdopen() for smtp_out failed", US"", errno);
168 goto ERROR_RETURN;
169 }
170
171 dup_accept_socket = dup(accept_socket);
172 if (dup_accept_socket < 0)
173 {
174 never_error(US"daemon: couldn't dup socket descriptor",
175 US"Connection setup failed", errno);
176 goto ERROR_RETURN;
177 }
178
179 smtp_in = fdopen(dup_accept_socket, "rb");
180 if (smtp_in == NULL)
181 {
182 never_error(US"daemon: fdopen() for smtp_in failed",
183 US"Connection setup failed", errno);
184 goto ERROR_RETURN;
185 }
186
187 /* Get the data for the local interface address. Panic for most errors, but
188 "connection reset by peer" just means the connection went away. */
189
190 if (getsockname(accept_socket, (struct sockaddr *)(&interface_sockaddr),
191 &ifsize) < 0)
192 {
193 log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC),
194 "getsockname() failed: %s", strerror(errno));
195 smtp_printf("421 Local problem: getsockname() failed; please try again later\r\n");
196 goto ERROR_RETURN;
197 }
198
199 interface_address = host_ntoa(-1, &interface_sockaddr, NULL, &interface_port);
200 DEBUG(D_interface) debug_printf("interface address=%s port=%d\n",
201 interface_address, interface_port);
202
203 /* Build a string identifying the remote host and, if requested, the port and
204 the local interface data. This is for logging; at the end of this function the
205 memory is reclaimed. */
206
207 whofrom = string_append(whofrom, &wfsize, &wfptr, 3, "[", sender_host_address, "]");
208
209 if ((log_extra_selector & LX_incoming_port) != 0)
210 whofrom = string_append(whofrom, &wfsize, &wfptr, 2, ":", string_sprintf("%d",
211 sender_host_port));
212
213 if ((log_extra_selector & LX_incoming_interface) != 0)
214 whofrom = string_append(whofrom, &wfsize, &wfptr, 4, " I=[",
215 interface_address, "]:", string_sprintf("%d", interface_port));
216
217 whofrom[wfptr] = 0; /* Terminate the newly-built string */
218
219 /* Check maximum number of connections. We do not check for reserved
220 connections or unacceptable hosts here. That is done in the subprocess because
221 it might take some time. */
222
223 if (smtp_accept_max > 0 && smtp_accept_count >= smtp_accept_max)
224 {
225 DEBUG(D_any) debug_printf("rejecting SMTP connection: count=%d max=%d\n",
226 smtp_accept_count, smtp_accept_max);
227 smtp_printf("421 Too many concurrent SMTP connections; "
228 "please try again later.\r\n");
229 log_write(L_connection_reject,
230 LOG_MAIN, "Connection from %s refused: too many connections",
231 whofrom);
232 goto ERROR_RETURN;
233 }
234
235 /* If a load limit above which only reserved hosts are acceptable is defined,
236 get the load average here, and if there are in fact no reserved hosts, do
237 the test right away (saves a fork). If there are hosts, do the check in the
238 subprocess because it might take time. */
239
240 if (smtp_load_reserve >= 0)
241 {
242 load_average = OS_GETLOADAVG();
243 if (smtp_reserve_hosts == NULL && load_average > smtp_load_reserve)
244 {
245 DEBUG(D_any) debug_printf("rejecting SMTP connection: load average = %.2f\n",
246 (double)load_average/1000.0);
247 smtp_printf("421 Too much load; please try again later.\r\n");
248 log_write(L_connection_reject,
249 LOG_MAIN, "Connection from %s refused: load average = %.2f",
250 whofrom, (double)load_average/1000.0);
251 goto ERROR_RETURN;
252 }
253 }
254
255 /* Check that one specific host (strictly, IP address) is not hogging
256 resources. This is done here to prevent a denial of service attack by someone
257 forcing you to fork lots of times before denying service. The value of
258 smtp_accept_max_per_host is a string which is expanded. This makes it possible
259 to provide host-specific limits according to $sender_host address, but because
260 this is in the daemon mainline, only fast expansions (such as inline address
261 checks) should be used. The documentation is full of warnings. */
262
263 if (smtp_accept_max_per_host != NULL)
264 {
265 uschar *expanded = expand_string(smtp_accept_max_per_host);
266 if (expanded == NULL)
267 {
268 if (!expand_string_forcedfail)
269 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
270 "failed for %s: %s", whofrom, expand_string_message);
271 }
272 /* For speed, interpret a decimal number inline here */
273 else
274 {
275 uschar *s = expanded;
276 while (isdigit(*s))
277 max_for_this_host = max_for_this_host * 10 + *s++ - '0';
278 if (*s != 0)
279 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
280 "for %s contains non-digit: %s", whofrom, expanded);
281 }
282 }
283
284 /* If we have fewer connections than max_for_this_host, we can skip the tedious
285 per host_address checks. Note that at this stage smtp_accept_count contains the
286 count of *other* connections, not including this one. */
287
288 if ((max_for_this_host > 0) &&
289 (smtp_accept_count >= max_for_this_host))
290 {
291 int i;
292 int host_accept_count = 0;
293 int other_host_count = 0; /* keep a count of non matches to optimise */
294
295 for (i = 0; i < smtp_accept_max; ++i)
296 {
297 if (smtp_slots[i].host_address != NULL)
298 {
299 if (Ustrcmp(sender_host_address, smtp_slots[i].host_address) == 0)
300 host_accept_count++;
301 else
302 other_host_count++;
303
304 /* Testing all these strings is expensive - see if we can drop out
305 early, either by hitting the target, or finding there are not enough
306 connections left to make the target. */
307
308 if ((host_accept_count >= max_for_this_host) ||
309 ((smtp_accept_count - other_host_count) < max_for_this_host))
310 break;
311 }
312 }
313
314 if (host_accept_count >= max_for_this_host)
315 {
316 DEBUG(D_any) debug_printf("rejecting SMTP connection: too many from this "
317 "IP address: count=%d max=%d\n",
318 host_accept_count, max_for_this_host);
319 smtp_printf("421 Too many concurrent SMTP connections "
320 "from this IP address; please try again later.\r\n");
321 log_write(L_connection_reject,
322 LOG_MAIN, "Connection from %s refused: too many connections "
323 "from that IP address", whofrom);
324 goto ERROR_RETURN;
325 }
326 }
327
328 /* OK, the connection count checks have been passed. Before we can fork the
329 accepting process, we must first log the connection if requested. This logging
330 used to happen in the subprocess, but doing that means that the value of
331 smtp_accept_count can be out of step by the time it is logged. So we have to do
332 the logging here and accept the performance cost. Note that smtp_accept_count
333 hasn't yet been incremented to take account of this connection.
334
335 In order to minimize the cost (because this is going to happen for every
336 connection), do a preliminary selector test here. This saves ploughing through
337 the generalized logging code each time when the selector is false. If the
338 selector is set, check whether the host is on the list for logging. If not,
339 arrange to unset the selector in the subprocess. */
340
341 if ((log_write_selector & L_smtp_connection) != 0)
342 {
343 uschar *list = hosts_connection_nolog;
344 if (list != NULL && verify_check_host(&list) == OK)
345 use_log_write_selector &= ~L_smtp_connection;
346 else
347 log_write(L_smtp_connection, LOG_MAIN, "SMTP connection from %s "
348 "(TCP/IP connection count = %d)", whofrom, smtp_accept_count + 1);
349 }
350
351 /* Now we can fork the accepting process; do a lookup tidy, just in case any
352 expansion above did a lookup. */
353
354 search_tidyup();
355 pid = fork();
356
357 /* Handle the child process */
358
359 if (pid == 0)
360 {
361 int i;
362 int queue_only_reason = 0;
363 int old_pool = store_pool;
364 int save_debug_selector = debug_selector;
365 BOOL local_queue_only;
366 BOOL session_local_queue_only;
367 #ifdef SA_NOCLDWAIT
368 struct sigaction act;
369 #endif
370
371 smtp_accept_count++; /* So that it includes this process */
372
373 /* May have been modified for the subprocess */
374
375 log_write_selector = use_log_write_selector;
376
377 /* Get the local interface address into permanent store */
378
379 store_pool = POOL_PERM;
380 interface_address = string_copy(interface_address);
381 store_pool = old_pool;
382
383 /* Check for a tls-on-connect port */
384
385 if (host_is_tls_on_connect_port(interface_port)) tls_in.on_connect = TRUE;
386
387 /* Expand smtp_active_hostname if required. We do not do this any earlier,
388 because it may depend on the local interface address (indeed, that is most
389 likely what it depends on.) */
390
391 smtp_active_hostname = primary_hostname;
392 if (raw_active_hostname != NULL)
393 {
394 uschar *nah = expand_string(raw_active_hostname);
395 if (nah == NULL)
396 {
397 if (!expand_string_forcedfail)
398 {
399 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand \"%s\" "
400 "(smtp_active_hostname): %s", raw_active_hostname,
401 expand_string_message);
402 smtp_printf("421 Local configuration error; "
403 "please try again later.\r\n");
404 mac_smtp_fflush();
405 search_tidyup();
406 _exit(EXIT_FAILURE);
407 }
408 }
409 else if (nah[0] != 0) smtp_active_hostname = nah;
410 }
411
412 /* Initialize the queueing flags */
413
414 queue_check_only();
415 session_local_queue_only = queue_only;
416
417 /* Close the listening sockets, and set the SIGCHLD handler to SIG_IGN.
418 We also attempt to set things up so that children are automatically reaped,
419 but just in case this isn't available, there's a paranoid waitpid() in the
420 loop too (except for systems where we are sure it isn't needed). See the more
421 extensive comment before the reception loop in exim.c for a fuller
422 explanation of this logic. */
423
424 for (i = 0; i < listen_socket_count; i++) (void)close(listen_sockets[i]);
425
426 /* Set FD_CLOEXEC on the SMTP socket. We don't want any rogue child processes
427 to be able to communicate with them, under any circumstances. */
428 (void)fcntl(accept_socket, F_SETFD,
429 fcntl(accept_socket, F_GETFD) | FD_CLOEXEC);
430 (void)fcntl(dup_accept_socket, F_SETFD,
431 fcntl(dup_accept_socket, F_GETFD) | FD_CLOEXEC);
432
433 #ifdef SA_NOCLDWAIT
434 act.sa_handler = SIG_IGN;
435 sigemptyset(&(act.sa_mask));
436 act.sa_flags = SA_NOCLDWAIT;
437 sigaction(SIGCHLD, &act, NULL);
438 #else
439 signal(SIGCHLD, SIG_IGN);
440 #endif
441
442 /* Attempt to get an id from the sending machine via the RFC 1413
443 protocol. We do this in the sub-process in order not to hold up the
444 main process if there is any delay. Then set up the fullhost information
445 in case there is no HELO/EHLO.
446
447 If debugging is enabled only for the daemon, we must turn if off while
448 finding the id, but turn it on again afterwards so that information about the
449 incoming connection is output. */
450
451 if (debug_daemon) debug_selector = 0;
452 verify_get_ident(IDENT_PORT);
453 host_build_sender_fullhost();
454 debug_selector = save_debug_selector;
455
456 DEBUG(D_any)
457 debug_printf("Process %d is handling incoming connection from %s\n",
458 (int)getpid(), sender_fullhost);
459
460 /* Now disable debugging permanently if it's required only for the daemon
461 process. */
462
463 if (debug_daemon) debug_selector = 0;
464
465 /* If there are too many child processes for immediate delivery,
466 set the session_local_queue_only flag, which is initialized from the
467 configured value and may therefore already be TRUE. Leave logging
468 till later so it will have a message id attached. Note that there is no
469 possibility of re-calculating this per-message, because the value of
470 smtp_accept_count does not change in this subprocess. */
471
472 if (smtp_accept_queue > 0 && smtp_accept_count > smtp_accept_queue)
473 {
474 session_local_queue_only = TRUE;
475 queue_only_reason = 1;
476 }
477
478 /* Handle the start of the SMTP session, then loop, accepting incoming
479 messages from the SMTP connection. The end will come at the QUIT command,
480 when smtp_setup_msg() returns 0. A break in the connection causes the
481 process to die (see accept.c).
482
483 NOTE: We do *not* call smtp_log_no_mail() if smtp_start_session() fails,
484 because a log line has already been written for all its failure exists
485 (usually "connection refused: <reason>") and writing another one is
486 unnecessary clutter. */
487
488 if (!smtp_start_session())
489 {
490 mac_smtp_fflush();
491 search_tidyup();
492 _exit(EXIT_SUCCESS);
493 }
494
495 for (;;)
496 {
497 int rc;
498 message_id[0] = 0; /* Clear out any previous message_id */
499 reset_point = store_get(0); /* Save current store high water point */
500
501 DEBUG(D_any)
502 debug_printf("Process %d is ready for new message\n", (int)getpid());
503
504 /* Smtp_setup_msg() returns 0 on QUIT or if the call is from an
505 unacceptable host or if an ACL "drop" command was triggered, -1 on
506 connection lost, and +1 on validly reaching DATA. Receive_msg() almost
507 always returns TRUE when smtp_input is true; just retry if no message was
508 accepted (can happen for invalid message parameters). However, it can yield
509 FALSE if the connection was forcibly dropped by the DATA ACL. */
510
511 if ((rc = smtp_setup_msg()) > 0)
512 {
513 BOOL ok = receive_msg(FALSE);
514 search_tidyup(); /* Close cached databases */
515 if (!ok) /* Connection was dropped */
516 {
517 mac_smtp_fflush();
518 smtp_log_no_mail(); /* Log no mail if configured */
519 _exit(EXIT_SUCCESS);
520 }
521 if (message_id[0] == 0) continue; /* No message was accepted */
522 }
523 else
524 {
525 mac_smtp_fflush();
526 search_tidyup();
527 smtp_log_no_mail(); /* Log no mail if configured */
528 _exit((rc == 0)? EXIT_SUCCESS : EXIT_FAILURE);
529 }
530
531 /* Show the recipients when debugging */
532
533 DEBUG(D_receive)
534 {
535 int i;
536 if (sender_address != NULL)
537 debug_printf("Sender: %s\n", sender_address);
538 if (recipients_list != NULL)
539 {
540 debug_printf("Recipients:\n");
541 for (i = 0; i < recipients_count; i++)
542 debug_printf(" %s\n", recipients_list[i].address);
543 }
544 }
545
546 /* A message has been accepted. Clean up any previous delivery processes
547 that have completed and are defunct, on systems where they don't go away
548 by themselves (see comments when setting SIG_IGN above). On such systems
549 (if any) these delivery processes hang around after termination until
550 the next message is received. */
551
552 #ifndef SIG_IGN_WORKS
553 while (waitpid(-1, NULL, WNOHANG) > 0);
554 #endif
555
556 /* Reclaim up the store used in accepting this message */
557
558 store_reset(reset_point);
559
560 /* If queue_only is set or if there are too many incoming connections in
561 existence, session_local_queue_only will be TRUE. If it is not, check
562 whether we have received too many messages in this session for immediate
563 delivery. */
564
565 if (!session_local_queue_only &&
566 smtp_accept_queue_per_connection > 0 &&
567 receive_messagecount > smtp_accept_queue_per_connection)
568 {
569 session_local_queue_only = TRUE;
570 queue_only_reason = 2;
571 }
572
573 /* Initialize local_queue_only from session_local_queue_only. If it is not
574 true, and queue_only_load is set, check that the load average is below it.
575 If local_queue_only is set by this means, we also set if for the session if
576 queue_only_load_latch is true (the default). This means that, once set,
577 local_queue_only remains set for any subsequent messages on the same SMTP
578 connection. This is a deliberate choice; even though the load average may
579 fall, it doesn't seem right to deliver later messages on the same call when
580 not delivering earlier ones. However, the are special circumstances such as
581 very long-lived connections from scanning appliances where this is not the
582 best strategy. In such cases, queue_only_load_latch should be set false. */
583
584 local_queue_only = session_local_queue_only;
585 if (!local_queue_only && queue_only_load >= 0)
586 {
587 local_queue_only = (load_average = OS_GETLOADAVG()) > queue_only_load;
588 if (local_queue_only)
589 {
590 queue_only_reason = 3;
591 if (queue_only_load_latch) session_local_queue_only = TRUE;
592 }
593 }
594
595 /* Log the queueing here, when it will get a message id attached, but
596 not if queue_only is set (case 0). */
597
598 if (local_queue_only) switch(queue_only_reason)
599 {
600 case 1:
601 log_write(L_delay_delivery,
602 LOG_MAIN, "no immediate delivery: too many connections "
603 "(%d, max %d)", smtp_accept_count, smtp_accept_queue);
604 break;
605
606 case 2:
607 log_write(L_delay_delivery,
608 LOG_MAIN, "no immediate delivery: more than %d messages "
609 "received in one connection", smtp_accept_queue_per_connection);
610 break;
611
612 case 3:
613 log_write(L_delay_delivery,
614 LOG_MAIN, "no immediate delivery: load average %.2f",
615 (double)load_average/1000.0);
616 break;
617 }
618
619 /* If a delivery attempt is required, spin off a new process to handle it.
620 If we are not root, we have to re-exec exim unless deliveries are being
621 done unprivileged. */
622
623 else if (!queue_only_policy && !deliver_freeze)
624 {
625 pid_t dpid;
626
627 /* Before forking, ensure that the C output buffer is flushed. Otherwise
628 anything that it in it will get duplicated, leading to duplicate copies
629 of the pending output. */
630
631 mac_smtp_fflush();
632
633 if ((dpid = fork()) == 0)
634 {
635 (void)fclose(smtp_in);
636 (void)fclose(smtp_out);
637
638 /* Don't ever molest the parent's SSL connection, but do clean up
639 the data structures if necessary. */
640
641 #ifdef SUPPORT_TLS
642 tls_close(TRUE, FALSE);
643 #endif
644
645 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
646
647 signal(SIGHUP, SIG_DFL);
648 signal(SIGCHLD, SIG_DFL);
649
650 if (geteuid() != root_uid && !deliver_drop_privilege)
651 {
652 signal(SIGALRM, SIG_DFL);
653 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 2, US"-Mc",
654 message_id);
655 /* Control does not return here. */
656 }
657
658 /* No need to re-exec; SIGALRM remains set to the default handler */
659
660 (void)deliver_message(message_id, FALSE, FALSE);
661 search_tidyup();
662 _exit(EXIT_SUCCESS);
663 }
664
665 if (dpid > 0)
666 {
667 DEBUG(D_any) debug_printf("forked delivery process %d\n", (int)dpid);
668 }
669 else
670 {
671 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: delivery process fork "
672 "failed: %s", strerror(errno));
673 }
674 }
675 }
676 }
677
678
679 /* Carrying on in the parent daemon process... Can't do much if the fork
680 failed. Otherwise, keep count of the number of accepting processes and
681 remember the pid for ticking off when the child completes. */
682
683 if (pid < 0)
684 {
685 never_error(US"daemon: accept process fork failed", US"Fork failed", errno);
686 }
687 else
688 {
689 int i;
690 for (i = 0; i < smtp_accept_max; ++i)
691 {
692 if (smtp_slots[i].pid <= 0)
693 {
694 smtp_slots[i].pid = pid;
695 if (smtp_accept_max_per_host != NULL)
696 smtp_slots[i].host_address = string_copy_malloc(sender_host_address);
697 smtp_accept_count++;
698 break;
699 }
700 }
701 DEBUG(D_any) debug_printf("%d SMTP accept process%s running\n",
702 smtp_accept_count, (smtp_accept_count == 1)? "" : "es");
703 }
704
705 /* Get here via goto in error cases */
706
707 ERROR_RETURN:
708
709 /* Close the streams associated with the socket which will also close the
710 socket fds in this process. We can't do anything if fclose() fails, but
711 logging brings it to someone's attention. However, "connection reset by peer"
712 isn't really a problem, so skip that one. On Solaris, a dropped connection can
713 manifest itself as a broken pipe, so drop that one too. If the streams don't
714 exist, something went wrong while setting things up. Make sure the socket
715 descriptors are closed, in order to drop the connection. */
716
717 if (smtp_out != NULL)
718 {
719 if (fclose(smtp_out) != 0 && errno != ECONNRESET && errno != EPIPE)
720 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_out) failed: %s",
721 strerror(errno));
722 smtp_out = NULL;
723 }
724 else (void)close(accept_socket);
725
726 if (smtp_in != NULL)
727 {
728 if (fclose(smtp_in) != 0 && errno != ECONNRESET && errno != EPIPE)
729 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_in) failed: %s",
730 strerror(errno));
731 smtp_in = NULL;
732 }
733 else (void)close(dup_accept_socket);
734
735 /* Release any store used in this process, including the store used for holding
736 the incoming host address and an expanded active_hostname. */
737
738 store_reset(reset_point);
739 sender_host_address = NULL;
740 }
741
742
743
744
745 /*************************************************
746 * Check wildcard listen special cases *
747 *************************************************/
748
749 /* This function is used when binding and listening on lists of addresses and
750 ports. It tests for special cases of wildcard listening, when IPv4 and IPv6
751 sockets may interact in different ways in different operating systems. It is
752 passed an error number, the list of listening addresses, and the current
753 address. Two checks are available: for a previous wildcard IPv6 address, or for
754 a following wildcard IPv4 address, in both cases on the same port.
755
756 In practice, pairs of wildcard addresses should be adjacent in the address list
757 because they are sorted that way below.
758
759 Arguments:
760 eno the error number
761 addresses the list of addresses
762 ipa the current IP address
763 back if TRUE, check for previous wildcard IPv6 address
764 if FALSE, check for a following wildcard IPv4 address
765
766 Returns: TRUE or FALSE
767 */
768
769 static BOOL
770 check_special_case(int eno, ip_address_item *addresses, ip_address_item *ipa,
771 BOOL back)
772 {
773 ip_address_item *ipa2;
774
775 /* For the "back" case, if the failure was "address in use" for a wildcard IPv4
776 address, seek a previous IPv6 wildcard address on the same port. As it is
777 previous, it must have been successfully bound and be listening. Flag it as a
778 "6 including 4" listener. */
779
780 if (back)
781 {
782 if (eno != EADDRINUSE || ipa->address[0] != 0) return FALSE;
783 for (ipa2 = addresses; ipa2 != ipa; ipa2 = ipa2->next)
784 {
785 if (ipa2->address[1] == 0 && ipa2->port == ipa->port)
786 {
787 ipa2->v6_include_v4 = TRUE;
788 return TRUE;
789 }
790 }
791 }
792
793 /* For the "forward" case, if the current address is a wildcard IPv6 address,
794 we seek a following wildcard IPv4 address on the same port. */
795
796 else
797 {
798 if (ipa->address[0] != ':' || ipa->address[1] != 0) return FALSE;
799 for (ipa2 = ipa->next; ipa2 != NULL; ipa2 = ipa2->next)
800 if (ipa2->address[0] == 0 && ipa->port == ipa2->port) return TRUE;
801 }
802
803 return FALSE;
804 }
805
806
807
808
809 /*************************************************
810 * Handle terminating subprocesses *
811 *************************************************/
812
813 /* Handle the termination of child processes. Theoretically, this need be done
814 only when sigchld_seen is TRUE, but rumour has it that some systems lose
815 SIGCHLD signals at busy times, so to be on the safe side, this function is
816 called each time round. It shouldn't be too expensive.
817
818 Arguments: none
819 Returns: nothing
820 */
821
822 static void
823 handle_ending_processes(void)
824 {
825 int status;
826 pid_t pid;
827
828 while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
829 {
830 int i;
831 DEBUG(D_any)
832 {
833 debug_printf("child %d ended: status=0x%x\n", (int)pid, status);
834 #ifdef WCOREDUMP
835 if (WIFEXITED(status))
836 debug_printf(" normal exit, %d\n", WEXITSTATUS(status));
837 else if (WIFSIGNALED(status))
838 debug_printf(" signal exit, signal %d%s\n", WTERMSIG(status),
839 WCOREDUMP(status) ? " (core dumped)" : "");
840 #endif
841 }
842
843 /* If it's a listening daemon for which we are keeping track of individual
844 subprocesses, deal with an accepting process that has terminated. */
845
846 if (smtp_slots != NULL)
847 {
848 for (i = 0; i < smtp_accept_max; i++)
849 {
850 if (smtp_slots[i].pid == pid)
851 {
852 if (smtp_slots[i].host_address != NULL)
853 store_free(smtp_slots[i].host_address);
854 smtp_slots[i] = empty_smtp_slot;
855 if (--smtp_accept_count < 0) smtp_accept_count = 0;
856 DEBUG(D_any) debug_printf("%d SMTP accept process%s now running\n",
857 smtp_accept_count, (smtp_accept_count == 1)? "" : "es");
858 break;
859 }
860 }
861 if (i < smtp_accept_max) continue; /* Found an accepting process */
862 }
863
864 /* If it wasn't an accepting process, see if it was a queue-runner
865 process that we are tracking. */
866
867 if (queue_pid_slots != NULL)
868 {
869 for (i = 0; i < queue_run_max; i++)
870 {
871 if (queue_pid_slots[i] == pid)
872 {
873 queue_pid_slots[i] = 0;
874 if (--queue_run_count < 0) queue_run_count = 0;
875 DEBUG(D_any) debug_printf("%d queue-runner process%s now running\n",
876 queue_run_count, (queue_run_count == 1)? "" : "es");
877 break;
878 }
879 }
880 }
881 }
882 }
883
884
885
886 /*************************************************
887 * Exim Daemon Mainline *
888 *************************************************/
889
890 /* The daemon can do two jobs, either of which is optional:
891
892 (1) Listens for incoming SMTP calls and spawns off a sub-process to handle
893 each one. This is requested by the -bd option, with -oX specifying the SMTP
894 port on which to listen (for testing).
895
896 (2) Spawns a queue-running process every so often. This is controlled by the
897 -q option with a an interval time. (If no time is given, a single queue run
898 is done from the main function, and control doesn't get here.)
899
900 Root privilege is required in order to attach to port 25. Some systems require
901 it when calling socket() rather than bind(). To cope with all cases, we run as
902 root for both socket() and bind(). Some systems also require root in order to
903 write to the pid file directory. This function must therefore be called as root
904 if it is to work properly in all circumstances. Once the socket is bound and
905 the pid file written, root privilege is given up if there is an exim uid.
906
907 There are no arguments to this function, and it never returns. */
908
909 void
910 daemon_go(void)
911 {
912 struct passwd *pw;
913 int *listen_sockets = NULL;
914 int listen_socket_count = 0;
915 ip_address_item *addresses = NULL;
916 time_t last_connection_time = (time_t)0;
917
918 /* If any debugging options are set, turn on the D_pid bit so that all
919 debugging lines get the pid added. */
920
921 DEBUG(D_any|D_v) debug_selector |= D_pid;
922
923 if (inetd_wait_mode)
924 {
925 int on = 1;
926
927 listen_socket_count = 1;
928 listen_sockets = store_get(sizeof(int *));
929 (void) close(3);
930 if (dup2(0, 3) == -1)
931 {
932 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
933 "failed to dup inetd socket safely away: %s", strerror(errno));
934 }
935 listen_sockets[0] = 3;
936 (void) close(0);
937 (void) close(1);
938 (void) close(2);
939 exim_nullstd();
940
941 if (debug_file == stderr)
942 {
943 /* need a call to log_write before call to open debug_file, so that
944 log.c:file_path has been initialised. This is unfortunate. */
945 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
946
947 fclose(debug_file);
948 debug_file = NULL;
949 exim_nullstd(); /* re-open fd2 after we just closed it again */
950 debug_logging_activate(US"-wait", NULL);
951 }
952
953 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
954
955 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
956 our own buffering; we assume though that inetd set the socket REUSEADDR. */
957
958 if (tcp_nodelay) setsockopt(3, IPPROTO_TCP, TCP_NODELAY,
959 (uschar *)(&on), sizeof(on));
960 }
961
962
963 if (inetd_wait_mode || daemon_listen)
964 {
965 /* If any option requiring a load average to be available during the
966 reception of a message is set, call os_getloadavg() while we are root
967 for those OS for which this is necessary the first time it is called (in
968 order to perform an "open" on the kernel memory file). */
969
970 #ifdef LOAD_AVG_NEEDS_ROOT
971 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
972 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
973 (void)os_getloadavg();
974 #endif
975 }
976
977
978 /* Do the preparation for setting up a listener on one or more interfaces, and
979 possible on various ports. This is controlled by the combination of
980 local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
981 (which is a list of default ports to use for those items in local_interfaces
982 that do not specify a port). The -oX command line option can be used to
983 override one or both of these options.
984
985 If local_interfaces is not set, the default is to listen on all interfaces.
986 When it is set, it can include "all IPvx interfaces" as an item. This is useful
987 when different ports are in use.
988
989 It turns out that listening on all interfaces is messy in an IPv6 world,
990 because several different implementation approaches have been taken. This code
991 is now supposed to work with all of them. The point of difference is whether an
992 IPv6 socket that is listening on all interfaces will receive incoming IPv4
993 calls or not. We also have to cope with the case when IPv6 libraries exist, but
994 there is no IPv6 support in the kernel.
995
996 . On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
997 addresses. However, if an IPv4 socket is also listening on all interfaces,
998 calls are directed to the appropriate socket.
999
1000 . On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1001 give them as mapped addresses, but an attempt also to listen on an IPv4
1002 socket on all interfaces causes an error.
1003
1004 . On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1005 two sockets if you want to accept both kinds of call.
1006
1007 . FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1008 can be turned off, to make it behave like the versions of Linux described
1009 above.
1010
1011 . I heard a report that the USAGI IPv6 stack for Linux has implemented
1012 IPV6_V6ONLY.
1013
1014 So, what we do when IPv6 is supported is as follows:
1015
1016 (1) After it is set up, the list of interfaces is scanned for wildcard
1017 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1018 port, the list is re-arranged so that they are together, with the IPv6
1019 wildcard first.
1020
1021 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1022 carry on if an IPv4 wildcard socket for the same port follows later in the
1023 list. This allows Exim to carry on in the case when the kernel has no IPv6
1024 support.
1025
1026 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1027 option is defined. However, if setting fails, carry on regardless (but log
1028 the incident).
1029
1030 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1031 error.
1032
1033 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1034 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1035 port (which must have succeeded or we wouldn't have got this far), we
1036 assume we are in the situation where just a single socket is permitted,
1037 and ignore the error.
1038
1039 Phew!
1040
1041 The preparation code decodes options and sets up the relevant data. We do this
1042 first, so that we can return non-zero if there are any syntax errors, and also
1043 write to stderr. */
1044
1045 if (daemon_listen && !inetd_wait_mode)
1046 {
1047 int *default_smtp_port;
1048 int sep;
1049 int pct = 0;
1050 uschar *s;
1051 uschar *list;
1052 uschar *local_iface_source = US"local_interfaces";
1053 ip_address_item *ipa;
1054 ip_address_item **pipa;
1055
1056 /* If -oX was used, disable the writing of a pid file unless -oP was
1057 explicitly used to force it. Then scan the string given to -oX. Any items
1058 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1059 Any other items are used to override local_interfaces. */
1060
1061 if (override_local_interfaces != NULL)
1062 {
1063 uschar *new_smtp_port = NULL;
1064 uschar *new_local_interfaces = NULL;
1065 int portsize = 0;
1066 int portptr = 0;
1067 int ifacesize = 0;
1068 int ifaceptr = 0;
1069
1070 if (override_pid_file_path == NULL) write_pid = FALSE;
1071
1072 list = override_local_interfaces;
1073 sep = 0;
1074 while ((s = string_nextinlist(&list,&sep,big_buffer,big_buffer_size))
1075 != NULL)
1076 {
1077 uschar joinstr[4];
1078 uschar **ptr;
1079 int *sizeptr;
1080 int *ptrptr;
1081
1082 if (Ustrpbrk(s, ".:") == NULL)
1083 {
1084 ptr = &new_smtp_port;
1085 sizeptr = &portsize;
1086 ptrptr = &portptr;
1087 }
1088 else
1089 {
1090 ptr = &new_local_interfaces;
1091 sizeptr = &ifacesize;
1092 ptrptr = &ifaceptr;
1093 }
1094
1095 if (*ptr == NULL)
1096 {
1097 joinstr[0] = sep;
1098 joinstr[1] = ' ';
1099 *ptr = string_cat(*ptr, sizeptr, ptrptr, US"<", 1);
1100 }
1101
1102 *ptr = string_cat(*ptr, sizeptr, ptrptr, joinstr, 2);
1103 *ptr = string_cat(*ptr, sizeptr, ptrptr, s, Ustrlen(s));
1104 }
1105
1106 if (new_smtp_port != NULL)
1107 {
1108 new_smtp_port[portptr] = 0;
1109 daemon_smtp_port = new_smtp_port;
1110 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1111 daemon_smtp_port);
1112 }
1113
1114 if (new_local_interfaces != NULL)
1115 {
1116 new_local_interfaces[ifaceptr] = 0;
1117 local_interfaces = new_local_interfaces;
1118 local_iface_source = US"-oX data";
1119 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1120 local_interfaces);
1121 }
1122 }
1123
1124 /* Create a list of default SMTP ports, to be used if local_interfaces
1125 contains entries without explict ports. First count the number of ports, then
1126 build a translated list in a vector. */
1127
1128 list = daemon_smtp_port;
1129 sep = 0;
1130 while ((s = string_nextinlist(&list,&sep,big_buffer,big_buffer_size)))
1131 pct++;
1132 default_smtp_port = store_get((pct+1) * sizeof(int));
1133 list = daemon_smtp_port;
1134 sep = 0;
1135 for (pct = 0;
1136 (s = string_nextinlist(&list,&sep,big_buffer,big_buffer_size));
1137 pct++)
1138 {
1139 if (isdigit(*s))
1140 {
1141 uschar *end;
1142 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1143 if (end != s + Ustrlen(s))
1144 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1145 }
1146 else
1147 {
1148 struct servent *smtp_service = getservbyname(CS s, "tcp");
1149 if (!smtp_service)
1150 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1151 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1152 }
1153 }
1154 default_smtp_port[pct] = 0;
1155
1156 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1157
1158 list = tls_in.on_connect_ports;
1159 sep = 0;
1160 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1161 if (!isdigit(*s))
1162 {
1163 list = tls_in.on_connect_ports;
1164 tls_in.on_connect_ports = NULL;
1165 sep = 0;
1166 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1167 {
1168 if (!isdigit(*s))
1169 {
1170 struct servent *smtp_service = getservbyname(CS s, "tcp");
1171 if (!smtp_service)
1172 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1173 s= string_sprintf("%d", (int)ntohs(smtp_service->s_port));
1174 }
1175 tls_in.on_connect_ports = string_append_listele(tls_in.on_connect_ports,
1176 ':', s);
1177 }
1178 break;
1179 }
1180
1181 /* Create the list of local interfaces, possibly with ports included. This
1182 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1183 values are converted below. */
1184
1185 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1186
1187 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1188 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1189 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1190 anyway, but we need to know which are the wildcard addresses, and the shorter
1191 strings are neater.
1192
1193 In the same scan, fill in missing port numbers from the default list. When
1194 there is more than one item in the list, extra items are created. */
1195
1196 for (ipa = addresses; ipa != NULL; ipa = ipa->next)
1197 {
1198 int i;
1199
1200 if (Ustrcmp(ipa->address, "0.0.0.0") == 0) ipa->address[0] = 0;
1201 else if (Ustrcmp(ipa->address, "::0") == 0)
1202 {
1203 ipa->address[0] = ':';
1204 ipa->address[1] = 0;
1205 }
1206
1207 if (ipa->port > 0) continue;
1208
1209 if (daemon_smtp_port[0] <= 0)
1210 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1211 "%s and daemon_smtp_port is unset; cannot start daemon",
1212 (ipa->address[0] == 0)? US"\"all IPv4\"" :
1213 (ipa->address[1] == 0)? US"\"all IPv6\"" : ipa->address);
1214 ipa->port = default_smtp_port[0];
1215 for (i = 1; default_smtp_port[i] > 0; i++)
1216 {
1217 ip_address_item *new = store_get(sizeof(ip_address_item));
1218 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1219 new->port = default_smtp_port[i];
1220 new->next = ipa->next;
1221 ipa->next = new;
1222 ipa = new;
1223 }
1224 }
1225
1226 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1227 wildcard for the same port, ensure that (a) they are together and (b) the
1228 IPv6 address comes first. This makes handling the messy features easier, and
1229 also simplifies the construction of the "daemon started" log line. */
1230
1231 pipa = &addresses;
1232 for (ipa = addresses; ipa != NULL; pipa = &(ipa->next), ipa = ipa->next)
1233 {
1234 ip_address_item *ipa2;
1235
1236 /* Handle an IPv4 wildcard */
1237
1238 if (ipa->address[0] == 0)
1239 {
1240 for (ipa2 = ipa; ipa2->next != NULL; ipa2 = ipa2->next)
1241 {
1242 ip_address_item *ipa3 = ipa2->next;
1243 if (ipa3->address[0] == ':' &&
1244 ipa3->address[1] == 0 &&
1245 ipa3->port == ipa->port)
1246 {
1247 ipa2->next = ipa3->next;
1248 ipa3->next = ipa;
1249 *pipa = ipa3;
1250 break;
1251 }
1252 }
1253 }
1254
1255 /* Handle an IPv6 wildcard. */
1256
1257 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
1258 {
1259 for (ipa2 = ipa; ipa2->next != NULL; ipa2 = ipa2->next)
1260 {
1261 ip_address_item *ipa3 = ipa2->next;
1262 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1263 {
1264 ipa2->next = ipa3->next;
1265 ipa3->next = ipa->next;
1266 ipa->next = ipa3;
1267 ipa = ipa3;
1268 break;
1269 }
1270 }
1271 }
1272 }
1273
1274 /* Get a vector to remember all the sockets in */
1275
1276 for (ipa = addresses; ipa != NULL; ipa = ipa->next)
1277 listen_socket_count++;
1278 listen_sockets = store_get(sizeof(int *) * listen_socket_count);
1279
1280 } /* daemon_listen but not inetd_wait_mode */
1281
1282 if (daemon_listen)
1283 {
1284
1285 /* Do a sanity check on the max connects value just to save us from getting
1286 a huge amount of store. */
1287
1288 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1289
1290 /* There's no point setting smtp_accept_queue unless it is less than the max
1291 connects limit. The configuration reader ensures that the max is set if the
1292 queue-only option is set. */
1293
1294 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1295
1296 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1297 track of them for total number and queue/host limits. */
1298
1299 if (smtp_accept_max > 0)
1300 {
1301 int i;
1302 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot));
1303 for (i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
1304 }
1305 }
1306
1307 /* The variable background_daemon is always false when debugging, but
1308 can also be forced false in order to keep a non-debugging daemon in the
1309 foreground. If background_daemon is true, close all open file descriptors that
1310 we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1311 do this for inetd_wait mode.
1312
1313 This is protection against any called functions (in libraries, or in
1314 Perl, or whatever) that think they can write to stderr (or stdout). Before this
1315 was added, it was quite likely that an SMTP connection would use one of these
1316 file descriptors, in which case writing random stuff to it caused chaos.
1317
1318 Then disconnect from the controlling terminal, Most modern Unixes seem to have
1319 setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1320 setsid() can be #defined as a no-op, or as something else. */
1321
1322 if (background_daemon || inetd_wait_mode)
1323 {
1324 log_close_all(); /* Just in case anything was logged earlier */
1325 search_tidyup(); /* Just in case any were used in reading the config. */
1326 (void)close(0); /* Get rid of stdin/stdout/stderr */
1327 (void)close(1);
1328 (void)close(2);
1329 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
1330 log_stderr = NULL; /* So no attempt to copy paniclog output */
1331 }
1332
1333 if (background_daemon)
1334 {
1335 /* If the parent process of this one has pid == 1, we are re-initializing the
1336 daemon as the result of a SIGHUP. In this case, there is no need to do
1337 anything, because the controlling terminal has long gone. Otherwise, fork, in
1338 case current process is a process group leader (see 'man setsid' for an
1339 explanation) before calling setsid(). */
1340
1341 if (getppid() != 1)
1342 {
1343 pid_t pid = fork();
1344 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1345 "fork() failed when starting daemon: %s", strerror(errno));
1346 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1347 (void)setsid(); /* release controlling terminal */
1348 }
1349 }
1350
1351 /* We are now in the disconnected, daemon process (unless debugging). Set up
1352 the listening sockets if required. */
1353
1354 if (daemon_listen && !inetd_wait_mode)
1355 {
1356 int sk;
1357 int on = 1;
1358 ip_address_item *ipa;
1359
1360 /* For each IP address, create a socket, bind it to the appropriate port, and
1361 start listening. See comments above about IPv6 sockets that may or may not
1362 accept IPv4 calls when listening on all interfaces. We also have to cope with
1363 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1364 listening, provided a wildcard IPv4 socket for the same port follows. */
1365
1366 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1367 {
1368 BOOL wildcard;
1369 ip_address_item *ipa2;
1370 int af;
1371
1372 if (Ustrchr(ipa->address, ':') != NULL)
1373 {
1374 af = AF_INET6;
1375 wildcard = ipa->address[1] == 0;
1376 }
1377 else
1378 {
1379 af = AF_INET;
1380 wildcard = ipa->address[0] == 0;
1381 }
1382
1383 listen_sockets[sk] = ip_socket(SOCK_STREAM, af);
1384 if (listen_sockets[sk] < 0)
1385 {
1386 if (check_special_case(0, addresses, ipa, FALSE))
1387 {
1388 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1389 "listening (%s): will use IPv4", strerror(errno));
1390 goto SKIP_SOCKET;
1391 }
1392 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1393 (af == AF_INET6)? '6' : '4', strerror(errno));
1394 }
1395
1396 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1397 available. Just log failure (can get protocol not available, just like
1398 socket creation can). */
1399
1400 #ifdef IPV6_V6ONLY
1401 if (af == AF_INET6 && wildcard &&
1402 setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, (char *)(&on),
1403 sizeof(on)) < 0)
1404 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1405 "socket failed (%s): carrying on without it", strerror(errno));
1406 #endif /* IPV6_V6ONLY */
1407
1408 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1409 is being handled. Without this, a connection will prevent reuse of the
1410 smtp port for listening. */
1411
1412 if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR,
1413 (uschar *)(&on), sizeof(on)) < 0)
1414 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1415 "failed when starting daemon: %s", strerror(errno));
1416
1417 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1418 disable this because it breaks some broken clients. */
1419
1420 if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY,
1421 (uschar *)(&on), sizeof(on));
1422
1423 /* Now bind the socket to the required port; if Exim is being restarted
1424 it may not always be possible to bind immediately, even with SO_REUSEADDR
1425 set, so try 10 times, waiting between each try. After 10 failures, we give
1426 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1427 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1428 address for the same port, ignore the error on the grounds that we must be
1429 in a system where the IPv6 socket accepts both kinds of call. This is
1430 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1431 listen() stage instead. */
1432
1433 for(;;)
1434 {
1435 uschar *msg, *addr;
1436 if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break;
1437 if (check_special_case(errno, addresses, ipa, TRUE))
1438 {
1439 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1440 "listen() success; EADDRINUSE ignored\n");
1441 (void)close(listen_sockets[sk]);
1442 goto SKIP_SOCKET;
1443 }
1444 msg = US strerror(errno);
1445 addr = wildcard? ((af == AF_INET6)? US"(any IPv6)" : US"(any IPv4)") :
1446 ipa->address;
1447 if (daemon_startup_retries <= 0)
1448 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1449 "socket bind() to port %d for address %s failed: %s: "
1450 "daemon abandoned", ipa->port, addr, msg);
1451 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
1452 "failed: %s: waiting %s before trying again (%d more %s)",
1453 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1454 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1455 daemon_startup_retries--;
1456 sleep(daemon_startup_sleep);
1457 }
1458
1459 DEBUG(D_any)
1460 {
1461 if (wildcard)
1462 debug_printf("listening on all interfaces (IPv%c) port %d\n",
1463 (af == AF_INET6)? '6' : '4', ipa->port);
1464 else
1465 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
1466 }
1467
1468 /* Start listening on the bound socket, establishing the maximum backlog of
1469 connections that is allowed. On success, continue to the next address. */
1470
1471 if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0) continue;
1472
1473 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1474 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1475 and there was a previous successful IPv6 wildcard listen on the same port,
1476 we want to ignore the error on the grounds that we must be in a system
1477 where the IPv6 socket accepts both kinds of call. */
1478
1479 if (!check_special_case(errno, addresses, ipa, TRUE))
1480 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
1481 wildcard? ((af == AF_INET6)? US"(any IPv6)" : US"(any IPv4)") :
1482 ipa->address,
1483 strerror(errno));
1484
1485 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1486 "listen() success; EADDRINUSE ignored\n");
1487 (void)close(listen_sockets[sk]);
1488
1489 /* Come here if there has been a problem with the socket which we
1490 are going to ignore. We remove the address from the chain, and back up the
1491 counts. */
1492
1493 SKIP_SOCKET:
1494 sk--; /* Back up the count */
1495 listen_socket_count--; /* Reduce the total */
1496 if (ipa == addresses) addresses = ipa->next; else
1497 {
1498 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1499 ipa2->next = ipa->next;
1500 ipa = ipa2;
1501 }
1502 } /* End of bind/listen loop for each address */
1503 } /* End of setup for listening */
1504
1505
1506 /* If we are not listening, we want to write a pid file only if -oP was
1507 explicitly given. */
1508
1509 else if (override_pid_file_path == NULL) write_pid = FALSE;
1510
1511 /* Write the pid to a known file for assistance in identification, if required.
1512 We do this before giving up root privilege, because on some systems it is
1513 necessary to be root in order to write into the pid file directory. There's
1514 nothing to stop multiple daemons running, as long as no more than one listens
1515 on a given TCP/IP port on the same interface(s). However, in these
1516 circumstances it gets far too complicated to mess with pid file names
1517 automatically. Consequently, Exim 4 writes a pid file only
1518
1519 (a) When running in the test harness, or
1520 (b) When -bd is used and -oX is not used, or
1521 (c) When -oP is used to supply a path.
1522
1523 The variable daemon_write_pid is used to control this. */
1524
1525 if (running_in_test_harness || write_pid)
1526 {
1527 FILE *f;
1528
1529 if (override_pid_file_path != NULL)
1530 pid_file_path = override_pid_file_path;
1531
1532 if (pid_file_path[0] == 0)
1533 pid_file_path = string_sprintf("%s/exim-daemon.pid", spool_directory);
1534
1535 f = modefopen(pid_file_path, "wb", 0644);
1536 if (f != NULL)
1537 {
1538 (void)fprintf(f, "%d\n", (int)getpid());
1539 (void)fclose(f);
1540 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1541 }
1542 else
1543 {
1544 DEBUG(D_any)
1545 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
1546 pid_file_path));
1547 }
1548 }
1549
1550 /* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1551
1552 sighup_seen = FALSE;
1553 signal(SIGHUP, sighup_handler);
1554
1555 /* Give up root privilege at this point (assuming that exim_uid and exim_gid
1556 are not root). The third argument controls the running of initgroups().
1557 Normally we do this, in order to set up the groups for the Exim user. However,
1558 if we are not root at this time - some odd installations run that way - we
1559 cannot do this. */
1560
1561 exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1562
1563 /* Update the originator_xxx fields so that received messages as listed as
1564 coming from Exim, not whoever started the daemon. */
1565
1566 originator_uid = exim_uid;
1567 originator_gid = exim_gid;
1568 originator_login = ((pw = getpwuid(exim_uid)) != NULL)?
1569 string_copy_malloc(US pw->pw_name) : US"exim";
1570
1571 /* Get somewhere to keep the list of queue-runner pids if we are keeping track
1572 of them (and also if we are doing queue runs). */
1573
1574 if (queue_interval > 0 && queue_run_max > 0)
1575 {
1576 int i;
1577 queue_pid_slots = store_get(queue_run_max * sizeof(pid_t));
1578 for (i = 0; i < queue_run_max; i++) queue_pid_slots[i] = 0;
1579 }
1580
1581 /* Set up the handler for termination of child processes. */
1582
1583 sigchld_seen = FALSE;
1584 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
1585
1586 /* If we are to run the queue periodically, pretend the alarm has just gone
1587 off. This will cause the first queue-runner to get kicked off straight away. */
1588
1589 sigalrm_seen = (queue_interval > 0);
1590
1591 /* Log the start up of a daemon - at least one of listening or queue running
1592 must be set up. */
1593
1594 if (inetd_wait_mode)
1595 {
1596 uschar *p = big_buffer;
1597
1598 if (inetd_wait_timeout >= 0)
1599 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
1600 else
1601 sprintf(CS p, "with no wait timeout");
1602
1603 log_write(0, LOG_MAIN,
1604 "exim %s daemon started: pid=%d, launched with listening socket, %s",
1605 version_string, getpid(), big_buffer);
1606 set_process_info("daemon: pre-listening socket");
1607
1608 /* set up the timeout logic */
1609 sigalrm_seen = 1;
1610 }
1611
1612 else if (daemon_listen)
1613 {
1614 int i, j;
1615 int smtp_ports = 0;
1616 int smtps_ports = 0;
1617 ip_address_item *ipa;
1618 uschar *p = big_buffer;
1619 uschar *qinfo = (queue_interval > 0)?
1620 string_sprintf("-q%s", readconf_printtime(queue_interval))
1621 :
1622 US"no queue runs";
1623
1624 /* Build a list of listening addresses in big_buffer, but limit it to 10
1625 items. The style is for backwards compatibility.
1626
1627 It is now possible to have some ports listening for SMTPS (the old,
1628 deprecated protocol that starts TLS without using STARTTLS), and others
1629 listening for standard SMTP. Keep their listings separate. */
1630
1631 for (j = 0; j < 2; j++)
1632 {
1633 for (i = 0, ipa = addresses; i < 10 && ipa != NULL; i++, ipa = ipa->next)
1634 {
1635 /* First time round, look for SMTP ports; second time round, look for
1636 SMTPS ports. For the first one of each, insert leading text. */
1637
1638 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1639 {
1640 if (j == 0)
1641 {
1642 if (smtp_ports++ == 0)
1643 {
1644 memcpy(p, "SMTP on", 8);
1645 p += 7;
1646 }
1647 }
1648 else
1649 {
1650 if (smtps_ports++ == 0)
1651 {
1652 (void)sprintf(CS p, "%sSMTPS on",
1653 (smtp_ports == 0)? "":" and for ");
1654 while (*p != 0) p++;
1655 }
1656 }
1657
1658 /* Now the information about the port (and sometimes interface) */
1659
1660 if (ipa->address[0] == ':' && ipa->address[1] == 0)
1661 {
1662 if (ipa->next != NULL && ipa->next->address[0] == 0 &&
1663 ipa->next->port == ipa->port)
1664 {
1665 (void)sprintf(CS p, " port %d (IPv6 and IPv4)", ipa->port);
1666 ipa = ipa->next;
1667 }
1668 else if (ipa->v6_include_v4)
1669 (void)sprintf(CS p, " port %d (IPv6 with IPv4)", ipa->port);
1670 else
1671 (void)sprintf(CS p, " port %d (IPv6)", ipa->port);
1672 }
1673 else if (ipa->address[0] == 0)
1674 (void)sprintf(CS p, " port %d (IPv4)", ipa->port);
1675 else
1676 (void)sprintf(CS p, " [%s]:%d", ipa->address, ipa->port);
1677 while (*p != 0) p++;
1678 }
1679 }
1680
1681 if (ipa != NULL)
1682 {
1683 memcpy(p, " ...", 5);
1684 p += 4;
1685 }
1686 }
1687
1688 log_write(0, LOG_MAIN,
1689 "exim %s daemon started: pid=%d, %s, listening for %s",
1690 version_string, getpid(), qinfo, big_buffer);
1691 set_process_info("daemon: %s, listening for %s", qinfo, big_buffer);
1692 }
1693
1694 else
1695 {
1696 log_write(0, LOG_MAIN,
1697 "exim %s daemon started: pid=%d, -q%s, not listening for SMTP",
1698 version_string, getpid(), readconf_printtime(queue_interval));
1699 set_process_info("daemon: -q%s, not listening",
1700 readconf_printtime(queue_interval));
1701 }
1702
1703
1704 /* Close the log so it can be renamed and moved. In the few cases below where
1705 this long-running process writes to the log (always exceptional conditions), it
1706 closes the log afterwards, for the same reason. */
1707
1708 log_close_all();
1709
1710 DEBUG(D_any) debug_print_ids(US"daemon running with");
1711
1712 /* Any messages accepted via this route are going to be SMTP. */
1713
1714 smtp_input = TRUE;
1715
1716 /* Enter the never-ending loop... */
1717
1718 for (;;)
1719 {
1720 #if HAVE_IPV6
1721 struct sockaddr_in6 accepted;
1722 #else
1723 struct sockaddr_in accepted;
1724 #endif
1725
1726 EXIM_SOCKLEN_T len;
1727 pid_t pid;
1728
1729 /* This code is placed first in the loop, so that it gets obeyed at the
1730 start, before the first wait, for the queue-runner case, so that the first
1731 one can be started immediately.
1732
1733 The other option is that we have an inetd wait timeout specified to -bw. */
1734
1735 if (sigalrm_seen)
1736 {
1737 if (inetd_wait_timeout > 0)
1738 {
1739 time_t resignal_interval = inetd_wait_timeout;
1740
1741 if (last_connection_time == (time_t)0)
1742 {
1743 DEBUG(D_any)
1744 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
1745 }
1746 else
1747 {
1748 time_t now = time(NULL);
1749 if (now == (time_t)-1)
1750 {
1751 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
1752 }
1753 else
1754 {
1755 if ((now - last_connection_time) >= inetd_wait_timeout)
1756 {
1757 DEBUG(D_any)
1758 debug_printf("inetd wait timeout %d expired, ending daemon\n",
1759 inetd_wait_timeout);
1760 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
1761 version_string);
1762 exit(EXIT_SUCCESS);
1763 }
1764 else
1765 {
1766 resignal_interval -= (now - last_connection_time);
1767 }
1768 }
1769 }
1770
1771 sigalrm_seen = FALSE;
1772 alarm(resignal_interval);
1773 }
1774
1775 else
1776 {
1777 DEBUG(D_any) debug_printf("SIGALRM received\n");
1778
1779 /* Do a full queue run in a child process, if required, unless we already
1780 have enough queue runners on the go. If we are not running as root, a
1781 re-exec is required. */
1782
1783 if (queue_interval > 0 &&
1784 (queue_run_max <= 0 || queue_run_count < queue_run_max))
1785 {
1786 if ((pid = fork()) == 0)
1787 {
1788 int sk;
1789
1790 DEBUG(D_any) debug_printf("Starting queue-runner: pid %d\n",
1791 (int)getpid());
1792
1793 /* Disable debugging if it's required only for the daemon process. We
1794 leave the above message, because it ties up with the "child ended"
1795 debugging messages. */
1796
1797 if (debug_daemon) debug_selector = 0;
1798
1799 /* Close any open listening sockets in the child */
1800
1801 for (sk = 0; sk < listen_socket_count; sk++)
1802 (void)close(listen_sockets[sk]);
1803
1804 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
1805
1806 signal(SIGHUP, SIG_DFL);
1807 signal(SIGCHLD, SIG_DFL);
1808
1809 /* Re-exec if privilege has been given up, unless deliver_drop_
1810 privilege is set. Reset SIGALRM before exec(). */
1811
1812 if (geteuid() != root_uid && !deliver_drop_privilege)
1813 {
1814 uschar opt[8];
1815 uschar *p = opt;
1816 uschar *extra[5];
1817 int extracount = 1;
1818
1819 signal(SIGALRM, SIG_DFL);
1820 *p++ = '-';
1821 *p++ = 'q';
1822 if (queue_2stage) *p++ = 'q';
1823 if (queue_run_first_delivery) *p++ = 'i';
1824 if (queue_run_force) *p++ = 'f';
1825 if (deliver_force_thaw) *p++ = 'f';
1826 if (queue_run_local) *p++ = 'l';
1827 *p = 0;
1828 extra[0] = opt;
1829
1830 /* If -R or -S were on the original command line, ensure they get
1831 passed on. */
1832
1833 if (deliver_selectstring != NULL)
1834 {
1835 extra[extracount++] = deliver_selectstring_regex? US"-Rr" : US"-R";
1836 extra[extracount++] = deliver_selectstring;
1837 }
1838
1839 if (deliver_selectstring_sender != NULL)
1840 {
1841 extra[extracount++] = deliver_selectstring_sender_regex?
1842 US"-Sr" : US"-S";
1843 extra[extracount++] = deliver_selectstring_sender;
1844 }
1845
1846 /* Overlay this process with a new execution. */
1847
1848 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, TRUE, extracount,
1849 extra[0], extra[1], extra[2], extra[3], extra[4]);
1850
1851 /* Control never returns here. */
1852 }
1853
1854 /* No need to re-exec; SIGALRM remains set to the default handler */
1855
1856 queue_run(NULL, NULL, FALSE);
1857 _exit(EXIT_SUCCESS);
1858 }
1859
1860 if (pid < 0)
1861 {
1862 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
1863 "process failed: %s", strerror(errno));
1864 log_close_all();
1865 }
1866 else
1867 {
1868 int i;
1869 for (i = 0; i < queue_run_max; ++i)
1870 {
1871 if (queue_pid_slots[i] <= 0)
1872 {
1873 queue_pid_slots[i] = pid;
1874 queue_run_count++;
1875 break;
1876 }
1877 }
1878 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
1879 queue_run_count, (queue_run_count == 1)? "" : "es");
1880 }
1881 }
1882
1883 /* Reset the alarm clock */
1884
1885 sigalrm_seen = FALSE;
1886 alarm(queue_interval);
1887 }
1888
1889 } /* sigalrm_seen */
1890
1891
1892 /* Sleep till a connection happens if listening, and handle the connection if
1893 that is why we woke up. The FreeBSD operating system requires the use of
1894 select() before accept() because the latter function is not interrupted by
1895 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
1896 OS do notice signals in accept() but it does no harm to have the select()
1897 in for all of them - and it won't then be a lurking problem for ports to
1898 new OS. In fact, the later addition of listening on specific interfaces only
1899 requires this way of working anyway. */
1900
1901 if (daemon_listen)
1902 {
1903 int sk, lcount, select_errno;
1904 int max_socket = 0;
1905 BOOL select_failed = FALSE;
1906 fd_set select_listen;
1907
1908 FD_ZERO(&select_listen);
1909 for (sk = 0; sk < listen_socket_count; sk++)
1910 {
1911 FD_SET(listen_sockets[sk], &select_listen);
1912 if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk];
1913 }
1914
1915 DEBUG(D_any) debug_printf("Listening...\n");
1916
1917 /* In rare cases we may have had a SIGCHLD signal in the time between
1918 setting the handler (below) and getting back here. If so, pretend that the
1919 select() was interrupted so that we reap the child. This might still leave
1920 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
1921 only to do the reaping more quickly, it shouldn't result in anything other
1922 than a delay until something else causes a wake-up. */
1923
1924 if (sigchld_seen)
1925 {
1926 lcount = -1;
1927 errno = EINTR;
1928 }
1929 else
1930 {
1931 lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen,
1932 NULL, NULL, NULL);
1933 }
1934
1935 if (lcount < 0)
1936 {
1937 select_failed = TRUE;
1938 lcount = 1;
1939 }
1940
1941 /* Clean up any subprocesses that may have terminated. We need to do this
1942 here so that smtp_accept_max_per_host works when a connection to that host
1943 has completed, and we are about to accept a new one. When this code was
1944 later in the sequence, a new connection could be rejected, even though an
1945 old one had just finished. Preserve the errno from any select() failure for
1946 the use of the common select/accept error processing below. */
1947
1948 select_errno = errno;
1949 handle_ending_processes();
1950 errno = select_errno;
1951
1952 /* Loop for all the sockets that are currently ready to go. If select
1953 actually failed, we have set the count to 1 and select_failed=TRUE, so as
1954 to use the common error code for select/accept below. */
1955
1956 while (lcount-- > 0)
1957 {
1958 int accept_socket = -1;
1959 if (!select_failed)
1960 {
1961 for (sk = 0; sk < listen_socket_count; sk++)
1962 {
1963 if (FD_ISSET(listen_sockets[sk], &select_listen))
1964 {
1965 len = sizeof(accepted);
1966 accept_socket = accept(listen_sockets[sk],
1967 (struct sockaddr *)&accepted, &len);
1968 FD_CLR(listen_sockets[sk], &select_listen);
1969 break;
1970 }
1971 }
1972 }
1973
1974 /* If select or accept has failed and this was not caused by an
1975 interruption, log the incident and try again. With asymmetric TCP/IP
1976 routing errors such as "No route to network" have been seen here. Also
1977 "connection reset by peer" has been seen. These cannot be classed as
1978 disastrous errors, but they could fill up a lot of log. The code in smail
1979 crashes the daemon after 10 successive failures of accept, on the grounds
1980 that some OS fail continuously. Exim originally followed suit, but this
1981 appears to have caused problems. Now it just keeps going, but instead of
1982 logging each error, it batches them up when they are continuous. */
1983
1984 if (accept_socket < 0 && errno != EINTR)
1985 {
1986 if (accept_retry_count == 0)
1987 {
1988 accept_retry_errno = errno;
1989 accept_retry_select_failed = select_failed;
1990 }
1991 else
1992 {
1993 if (errno != accept_retry_errno ||
1994 select_failed != accept_retry_select_failed ||
1995 accept_retry_count >= 50)
1996 {
1997 log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0),
1998 "%d %s() failure%s: %s",
1999 accept_retry_count,
2000 accept_retry_select_failed? "select" : "accept",
2001 (accept_retry_count == 1)? "" : "s",
2002 strerror(accept_retry_errno));
2003 log_close_all();
2004 accept_retry_count = 0;
2005 accept_retry_errno = errno;
2006 accept_retry_select_failed = select_failed;
2007 }
2008 }
2009 accept_retry_count++;
2010 }
2011
2012 else
2013 {
2014 if (accept_retry_count > 0)
2015 {
2016 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2017 accept_retry_count,
2018 accept_retry_select_failed? "select" : "accept",
2019 (accept_retry_count == 1)? "" : "s",
2020 strerror(accept_retry_errno));
2021 log_close_all();
2022 accept_retry_count = 0;
2023 }
2024 }
2025
2026 /* If select/accept succeeded, deal with the connection. */
2027
2028 if (accept_socket >= 0)
2029 {
2030 if (inetd_wait_timeout)
2031 last_connection_time = time(NULL);
2032 handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,
2033 (struct sockaddr *)&accepted);
2034 }
2035 }
2036 }
2037
2038 /* If not listening, then just sleep for the queue interval. If we woke
2039 up early the last time for some other signal, it won't matter because
2040 the alarm signal will wake at the right time. This code originally used
2041 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2042 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2043 select() can be used as an interruptible sleep() on all versions of Unix. */
2044
2045 else
2046 {
2047 struct timeval tv;
2048 tv.tv_sec = queue_interval;
2049 tv.tv_usec = 0;
2050 select(0, NULL, NULL, NULL, &tv);
2051 handle_ending_processes();
2052 }
2053
2054 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2055 for itself, because it isn't doing the waiting itself. */
2056
2057 if (sigchld_seen)
2058 {
2059 sigchld_seen = FALSE;
2060 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
2061 }
2062
2063 /* Handle being woken by SIGHUP. We know at this point that the result
2064 of accept() has been dealt with, so we can re-exec exim safely, first
2065 closing the listening sockets so that they can be reused. Cancel any pending
2066 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2067 that another HUP in quick succession doesn't clobber the new daemon before it
2068 gets going. All log files get closed by the close-on-exec flag; however, if
2069 the exec fails, we need to close the logs. */
2070
2071 if (sighup_seen)
2072 {
2073 int sk;
2074 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2075 getpid());
2076 for (sk = 0; sk < listen_socket_count; sk++)
2077 (void)close(listen_sockets[sk]);
2078 alarm(0);
2079 signal(SIGHUP, SIG_IGN);
2080 sighup_argv[0] = exim_path;
2081 exim_nullstd();
2082 execv(CS exim_path, (char *const *)sighup_argv);
2083 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2084 getpid(), exim_path, strerror(errno));
2085 log_close_all();
2086 }
2087
2088 } /* End of main loop */
2089
2090 /* Control never reaches here */
2091 }
2092
2093 /* vi: aw ai sw=2
2094 */
2095 /* End of exim_daemon.c */