Replace "Try to fix Solaris build" with compatibility compiler flags
[exim.git] / src / src / daemon.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
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 assignments except as initializers in declarations). */
23
24 static smtp_slot empty_smtp_slot = { .pid = 0, .host_address = NULL };
25
26
27
28 /*************************************************
29 * Local static variables *
30 *************************************************/
31
32 static SIGNAL_BOOL sigchld_seen;
33 static SIGNAL_BOOL sighup_seen;
34 static SIGNAL_BOOL sigterm_seen;
35
36 static int accept_retry_count = 0;
37 static int accept_retry_errno;
38 static BOOL accept_retry_select_failed;
39
40 static int queue_run_count = 0;
41 static pid_t *queue_pid_slots = NULL;
42 static smtp_slot *smtp_slots = NULL;
43
44 static BOOL write_pid = TRUE;
45
46
47
48 /*************************************************
49 * SIGHUP Handler *
50 *************************************************/
51
52 /* All this handler does is to set a flag and re-enable the signal.
53
54 Argument: the signal number
55 Returns: nothing
56 */
57
58 static void
59 sighup_handler(int sig)
60 {
61 sig = sig; /* Keep picky compilers happy */
62 sighup_seen = TRUE;
63 signal(SIGHUP, sighup_handler);
64 }
65
66
67
68 /*************************************************
69 * SIGCHLD handler for main daemon process *
70 *************************************************/
71
72 /* Don't re-enable the handler here, since we aren't doing the
73 waiting here. If the signal is re-enabled, there will just be an
74 infinite sequence of calls to this handler. The SIGCHLD signal is
75 used just as a means of waking up the daemon so that it notices
76 terminated subprocesses as soon as possible.
77
78 Argument: the signal number
79 Returns: nothing
80 */
81
82 static void
83 main_sigchld_handler(int sig)
84 {
85 sig = sig; /* Keep picky compilers happy */
86 os_non_restarting_signal(SIGCHLD, SIG_DFL);
87 sigchld_seen = TRUE;
88 }
89
90
91 /* SIGTERM handler. Try to get the damon pif file removed
92 before exiting. */
93
94 static void
95 main_sigterm_handler(int sig)
96 {
97 sigterm_seen = TRUE;
98 }
99
100
101
102
103 /*************************************************
104 * Unexpected errors in SMTP calls *
105 *************************************************/
106
107 /* This function just saves a bit of repetitious coding.
108
109 Arguments:
110 log_msg Text of message to be logged
111 smtp_msg Text of SMTP error message
112 was_errno The failing errno
113
114 Returns: nothing
115 */
116
117 static void
118 never_error(uschar *log_msg, uschar *smtp_msg, int was_errno)
119 {
120 uschar *emsg = was_errno <= 0
121 ? US"" : string_sprintf(": %s", strerror(was_errno));
122 log_write(0, LOG_MAIN|LOG_PANIC, "%s%s", log_msg, emsg);
123 if (smtp_out) smtp_printf("421 %s\r\n", FALSE, smtp_msg);
124 }
125
126
127
128
129 /*************************************************
130 * Handle a connected SMTP call *
131 *************************************************/
132
133 /* This function is called when an SMTP connection has been accepted.
134 If there are too many, give an error message and close down. Otherwise
135 spin off a sub-process to handle the call. The list of listening sockets
136 is required so that they can be closed in the sub-process. Take care not to
137 leak store in this process - reset the stacking pool at the end.
138
139 Arguments:
140 listen_sockets sockets which are listening for incoming calls
141 listen_socket_count count of listening sockets
142 accept_socket socket of the current accepted call
143 accepted socket information about the current call
144
145 Returns: nothing
146 */
147
148 static void
149 handle_smtp_call(int *listen_sockets, int listen_socket_count,
150 int accept_socket, struct sockaddr *accepted)
151 {
152 pid_t pid;
153 union sockaddr_46 interface_sockaddr;
154 EXIM_SOCKLEN_T ifsize = sizeof(interface_sockaddr);
155 int dup_accept_socket = -1;
156 int max_for_this_host = 0;
157 int save_log_selector = *log_selector;
158 gstring * whofrom;
159
160 rmark reset_point = store_mark();
161
162 /* Make the address available in ASCII representation, and also fish out
163 the remote port. */
164
165 sender_host_address = host_ntoa(-1, accepted, NULL, &sender_host_port);
166 DEBUG(D_any) debug_printf("Connection request from %s port %d\n",
167 sender_host_address, sender_host_port);
168
169 /* Set up the output stream, check the socket has duplicated, and set up the
170 input stream. These operations fail only the exceptional circumstances. Note
171 that never_error() won't use smtp_out if it is NULL. */
172
173 if (!(smtp_out = fdopen(accept_socket, "wb")))
174 {
175 never_error(US"daemon: fdopen() for smtp_out failed", US"", errno);
176 goto ERROR_RETURN;
177 }
178
179 if ((dup_accept_socket = dup(accept_socket)) < 0)
180 {
181 never_error(US"daemon: couldn't dup socket descriptor",
182 US"Connection setup failed", errno);
183 goto ERROR_RETURN;
184 }
185
186 if (!(smtp_in = fdopen(dup_accept_socket, "rb")))
187 {
188 never_error(US"daemon: fdopen() for smtp_in failed",
189 US"Connection setup failed", errno);
190 goto ERROR_RETURN;
191 }
192
193 /* Get the data for the local interface address. Panic for most errors, but
194 "connection reset by peer" just means the connection went away. */
195
196 if (getsockname(accept_socket, (struct sockaddr *)(&interface_sockaddr),
197 &ifsize) < 0)
198 {
199 log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC),
200 "getsockname() failed: %s", strerror(errno));
201 smtp_printf("421 Local problem: getsockname() failed; please try again later\r\n", FALSE);
202 goto ERROR_RETURN;
203 }
204
205 interface_address = host_ntoa(-1, &interface_sockaddr, NULL, &interface_port);
206 DEBUG(D_interface) debug_printf("interface address=%s port=%d\n",
207 interface_address, interface_port);
208
209 /* Build a string identifying the remote host and, if requested, the port and
210 the local interface data. This is for logging; at the end of this function the
211 memory is reclaimed. */
212
213 whofrom = string_append(NULL, 3, "[", sender_host_address, "]");
214
215 if (LOGGING(incoming_port))
216 whofrom = string_fmt_append(whofrom, ":%d", sender_host_port);
217
218 if (LOGGING(incoming_interface))
219 whofrom = string_fmt_append(whofrom, " I=[%s]:%d",
220 interface_address, interface_port);
221
222 (void) string_from_gstring(whofrom); /* Terminate the newly-built string */
223
224 /* Check maximum number of connections. We do not check for reserved
225 connections or unacceptable hosts here. That is done in the subprocess because
226 it might take some time. */
227
228 if (smtp_accept_max > 0 && smtp_accept_count >= smtp_accept_max)
229 {
230 DEBUG(D_any) debug_printf("rejecting SMTP connection: count=%d max=%d\n",
231 smtp_accept_count, smtp_accept_max);
232 smtp_printf("421 Too many concurrent SMTP connections; "
233 "please try again later.\r\n", FALSE);
234 log_write(L_connection_reject,
235 LOG_MAIN, "Connection from %s refused: too many connections",
236 whofrom->s);
237 goto ERROR_RETURN;
238 }
239
240 /* If a load limit above which only reserved hosts are acceptable is defined,
241 get the load average here, and if there are in fact no reserved hosts, do
242 the test right away (saves a fork). If there are hosts, do the check in the
243 subprocess because it might take time. */
244
245 if (smtp_load_reserve >= 0)
246 {
247 load_average = OS_GETLOADAVG();
248 if (smtp_reserve_hosts == NULL && load_average > smtp_load_reserve)
249 {
250 DEBUG(D_any) debug_printf("rejecting SMTP connection: load average = %.2f\n",
251 (double)load_average/1000.0);
252 smtp_printf("421 Too much load; please try again later.\r\n", FALSE);
253 log_write(L_connection_reject,
254 LOG_MAIN, "Connection from %s refused: load average = %.2f",
255 whofrom->s, (double)load_average/1000.0);
256 goto ERROR_RETURN;
257 }
258 }
259
260 /* Check that one specific host (strictly, IP address) is not hogging
261 resources. This is done here to prevent a denial of service attack by someone
262 forcing you to fork lots of times before denying service. The value of
263 smtp_accept_max_per_host is a string which is expanded. This makes it possible
264 to provide host-specific limits according to $sender_host address, but because
265 this is in the daemon mainline, only fast expansions (such as inline address
266 checks) should be used. The documentation is full of warnings. */
267
268 if (smtp_accept_max_per_host != NULL)
269 {
270 uschar *expanded = expand_string(smtp_accept_max_per_host);
271 if (expanded == NULL)
272 {
273 if (!f.expand_string_forcedfail)
274 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
275 "failed for %s: %s", whofrom->s, expand_string_message);
276 }
277 /* For speed, interpret a decimal number inline here */
278 else
279 {
280 uschar *s = expanded;
281 while (isdigit(*s))
282 max_for_this_host = max_for_this_host * 10 + *s++ - '0';
283 if (*s != 0)
284 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
285 "for %s contains non-digit: %s", whofrom->s, expanded);
286 }
287 }
288
289 /* If we have fewer connections than max_for_this_host, we can skip the tedious
290 per host_address checks. Note that at this stage smtp_accept_count contains the
291 count of *other* connections, not including this one. */
292
293 if ((max_for_this_host > 0) &&
294 (smtp_accept_count >= max_for_this_host))
295 {
296 int host_accept_count = 0;
297 int other_host_count = 0; /* keep a count of non matches to optimise */
298
299 for (int i = 0; i < smtp_accept_max; ++i)
300 if (smtp_slots[i].host_address)
301 {
302 if (Ustrcmp(sender_host_address, smtp_slots[i].host_address) == 0)
303 host_accept_count++;
304 else
305 other_host_count++;
306
307 /* Testing all these strings is expensive - see if we can drop out
308 early, either by hitting the target, or finding there are not enough
309 connections left to make the target. */
310
311 if ((host_accept_count >= max_for_this_host) ||
312 ((smtp_accept_count - other_host_count) < max_for_this_host))
313 break;
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", FALSE);
323 log_write(L_connection_reject,
324 LOG_MAIN, "Connection from %s refused: too many connections "
325 "from that IP address", whofrom->s);
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 (LOGGING(smtp_connection))
344 {
345 uschar *list = hosts_connection_nolog;
346 memset(sender_host_cache, 0, sizeof(sender_host_cache));
347 if (list != NULL && verify_check_host(&list) == OK)
348 save_log_selector &= ~L_smtp_connection;
349 else
350 log_write(L_smtp_connection, LOG_MAIN, "SMTP connection from %s "
351 "(TCP/IP connection count = %d)", whofrom->s, smtp_accept_count + 1);
352 }
353
354 /* Now we can fork the accepting process; do a lookup tidy, just in case any
355 expansion above did a lookup. */
356
357 search_tidyup();
358 pid = fork();
359
360 /* Handle the child process */
361
362 if (pid == 0)
363 {
364 int i;
365 int queue_only_reason = 0;
366 int old_pool = store_pool;
367 int save_debug_selector = debug_selector;
368 BOOL local_queue_only;
369 BOOL session_local_queue_only;
370 #ifdef SA_NOCLDWAIT
371 struct sigaction act;
372 #endif
373
374 smtp_accept_count++; /* So that it includes this process */
375
376 /* May have been modified for the subprocess */
377
378 *log_selector = save_log_selector;
379
380 /* Get the local interface address into permanent store */
381
382 store_pool = POOL_PERM;
383 interface_address = string_copy(interface_address);
384 store_pool = old_pool;
385
386 /* Check for a tls-on-connect port */
387
388 if (host_is_tls_on_connect_port(interface_port)) tls_in.on_connect = TRUE;
389
390 /* Expand smtp_active_hostname if required. We do not do this any earlier,
391 because it may depend on the local interface address (indeed, that is most
392 likely what it depends on.) */
393
394 smtp_active_hostname = primary_hostname;
395 if (raw_active_hostname)
396 {
397 uschar * nah = expand_string(raw_active_hostname);
398 if (!nah)
399 {
400 if (!f.expand_string_forcedfail)
401 {
402 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand \"%s\" "
403 "(smtp_active_hostname): %s", raw_active_hostname,
404 expand_string_message);
405 smtp_printf("421 Local configuration error; "
406 "please try again later.\r\n", FALSE);
407 mac_smtp_fflush();
408 search_tidyup();
409 exim_underbar_exit(EXIT_FAILURE);
410 }
411 }
412 else if (*nah) smtp_active_hostname = nah;
413 }
414
415 /* Initialize the queueing flags */
416
417 queue_check_only();
418 session_local_queue_only = queue_only;
419
420 /* Close the listening sockets, and set the SIGCHLD handler to SIG_IGN.
421 We also attempt to set things up so that children are automatically reaped,
422 but just in case this isn't available, there's a paranoid waitpid() in the
423 loop too (except for systems where we are sure it isn't needed). See the more
424 extensive comment before the reception loop in exim.c for a fuller
425 explanation of this logic. */
426
427 for (i = 0; i < listen_socket_count; i++) (void)close(listen_sockets[i]);
428
429 /* Set FD_CLOEXEC on the SMTP socket. We don't want any rogue child processes
430 to be able to communicate with them, under any circumstances. */
431 (void)fcntl(accept_socket, F_SETFD,
432 fcntl(accept_socket, F_GETFD) | FD_CLOEXEC);
433 (void)fcntl(dup_accept_socket, F_SETFD,
434 fcntl(dup_accept_socket, F_GETFD) | FD_CLOEXEC);
435
436 #ifdef SA_NOCLDWAIT
437 act.sa_handler = SIG_IGN;
438 sigemptyset(&(act.sa_mask));
439 act.sa_flags = SA_NOCLDWAIT;
440 sigaction(SIGCHLD, &act, NULL);
441 #else
442 signal(SIGCHLD, SIG_IGN);
443 #endif
444 signal(SIGTERM, SIG_DFL);
445
446 /* Attempt to get an id from the sending machine via the RFC 1413
447 protocol. We do this in the sub-process in order not to hold up the
448 main process if there is any delay. Then set up the fullhost information
449 in case there is no HELO/EHLO.
450
451 If debugging is enabled only for the daemon, we must turn if off while
452 finding the id, but turn it on again afterwards so that information about the
453 incoming connection is output. */
454
455 if (f.debug_daemon) debug_selector = 0;
456 verify_get_ident(IDENT_PORT);
457 host_build_sender_fullhost();
458 debug_selector = save_debug_selector;
459
460 DEBUG(D_any)
461 debug_printf("Process %d is handling incoming connection from %s\n",
462 (int)getpid(), sender_fullhost);
463
464 /* Now disable debugging permanently if it's required only for the daemon
465 process. */
466
467 if (f.debug_daemon) debug_selector = 0;
468
469 /* If there are too many child processes for immediate delivery,
470 set the session_local_queue_only flag, which is initialized from the
471 configured value and may therefore already be TRUE. Leave logging
472 till later so it will have a message id attached. Note that there is no
473 possibility of re-calculating this per-message, because the value of
474 smtp_accept_count does not change in this subprocess. */
475
476 if (smtp_accept_queue > 0 && smtp_accept_count > smtp_accept_queue)
477 {
478 session_local_queue_only = TRUE;
479 queue_only_reason = 1;
480 }
481
482 /* Handle the start of the SMTP session, then loop, accepting incoming
483 messages from the SMTP connection. The end will come at the QUIT command,
484 when smtp_setup_msg() returns 0. A break in the connection causes the
485 process to die (see accept.c).
486
487 NOTE: We do *not* call smtp_log_no_mail() if smtp_start_session() fails,
488 because a log line has already been written for all its failure exists
489 (usually "connection refused: <reason>") and writing another one is
490 unnecessary clutter. */
491
492 if (!smtp_start_session())
493 {
494 mac_smtp_fflush();
495 search_tidyup();
496 exim_underbar_exit(EXIT_SUCCESS);
497 }
498
499 for (;;)
500 {
501 int rc;
502 message_id[0] = 0; /* Clear out any previous message_id */
503 reset_point = store_mark(); /* Save current store high water point */
504
505 DEBUG(D_any)
506 debug_printf("Process %d is ready for new message\n", (int)getpid());
507
508 /* Smtp_setup_msg() returns 0 on QUIT or if the call is from an
509 unacceptable host or if an ACL "drop" command was triggered, -1 on
510 connection lost, and +1 on validly reaching DATA. Receive_msg() almost
511 always returns TRUE when smtp_input is true; just retry if no message was
512 accepted (can happen for invalid message parameters). However, it can yield
513 FALSE if the connection was forcibly dropped by the DATA ACL. */
514
515 if ((rc = smtp_setup_msg()) > 0)
516 {
517 BOOL ok = receive_msg(FALSE);
518 search_tidyup(); /* Close cached databases */
519 if (!ok) /* Connection was dropped */
520 {
521 cancel_cutthrough_connection(TRUE, US"receive dropped");
522 mac_smtp_fflush();
523 smtp_log_no_mail(); /* Log no mail if configured */
524 exim_underbar_exit(EXIT_SUCCESS);
525 }
526 if (message_id[0] == 0) continue; /* No message was accepted */
527 }
528 else
529 {
530 if (smtp_out)
531 {
532 int fd = fileno(smtp_in);
533 uschar buf[128];
534
535 mac_smtp_fflush();
536 /* drain socket, for clean TCP FINs */
537 if (fcntl(fd, F_SETFL, O_NONBLOCK) == 0)
538 for(int i = 16; read(fd, buf, sizeof(buf)) > 0 && i > 0; ) i--;
539 }
540 cancel_cutthrough_connection(TRUE, US"message setup dropped");
541 search_tidyup();
542 smtp_log_no_mail(); /* Log no mail if configured */
543
544 /*XXX should we pause briefly, hoping that the client will be the
545 active TCP closer hence get the TCP_WAIT endpoint? */
546 DEBUG(D_receive) debug_printf("SMTP>>(close on process exit)\n");
547 exim_underbar_exit(rc ? EXIT_FAILURE : EXIT_SUCCESS);
548 }
549
550 /* Show the recipients when debugging */
551
552 DEBUG(D_receive)
553 {
554 if (sender_address)
555 debug_printf("Sender: %s\n", sender_address);
556 if (recipients_list)
557 {
558 debug_printf("Recipients:\n");
559 for (int i = 0; i < recipients_count; i++)
560 debug_printf(" %s\n", recipients_list[i].address);
561 }
562 }
563
564 /* A message has been accepted. Clean up any previous delivery processes
565 that have completed and are defunct, on systems where they don't go away
566 by themselves (see comments when setting SIG_IGN above). On such systems
567 (if any) these delivery processes hang around after termination until
568 the next message is received. */
569
570 #ifndef SIG_IGN_WORKS
571 while (waitpid(-1, NULL, WNOHANG) > 0);
572 #endif
573
574 /* Reclaim up the store used in accepting this message */
575
576 {
577 int r = receive_messagecount;
578 BOOL q = f.queue_only_policy;
579 smtp_reset(reset_point);
580 reset_point = NULL;
581 f.queue_only_policy = q;
582 receive_messagecount = r;
583 }
584
585 /* If queue_only is set or if there are too many incoming connections in
586 existence, session_local_queue_only will be TRUE. If it is not, check
587 whether we have received too many messages in this session for immediate
588 delivery. */
589
590 if (!session_local_queue_only &&
591 smtp_accept_queue_per_connection > 0 &&
592 receive_messagecount > smtp_accept_queue_per_connection)
593 {
594 session_local_queue_only = TRUE;
595 queue_only_reason = 2;
596 }
597
598 /* Initialize local_queue_only from session_local_queue_only. If it is not
599 true, and queue_only_load is set, check that the load average is below it.
600 If local_queue_only is set by this means, we also set if for the session if
601 queue_only_load_latch is true (the default). This means that, once set,
602 local_queue_only remains set for any subsequent messages on the same SMTP
603 connection. This is a deliberate choice; even though the load average may
604 fall, it doesn't seem right to deliver later messages on the same call when
605 not delivering earlier ones. However, the are special circumstances such as
606 very long-lived connections from scanning appliances where this is not the
607 best strategy. In such cases, queue_only_load_latch should be set false. */
608
609 if ( !(local_queue_only = session_local_queue_only)
610 && queue_only_load >= 0
611 && (local_queue_only = (load_average = OS_GETLOADAVG()) > queue_only_load)
612 )
613 {
614 queue_only_reason = 3;
615 if (queue_only_load_latch) session_local_queue_only = TRUE;
616 }
617
618 /* Log the queueing here, when it will get a message id attached, but
619 not if queue_only is set (case 0). */
620
621 if (local_queue_only) switch(queue_only_reason)
622 {
623 case 1: log_write(L_delay_delivery,
624 LOG_MAIN, "no immediate delivery: too many connections "
625 "(%d, max %d)", smtp_accept_count, smtp_accept_queue);
626 break;
627
628 case 2: log_write(L_delay_delivery,
629 LOG_MAIN, "no immediate delivery: more than %d messages "
630 "received in one connection", smtp_accept_queue_per_connection);
631 break;
632
633 case 3: log_write(L_delay_delivery,
634 LOG_MAIN, "no immediate delivery: load average %.2f",
635 (double)load_average/1000.0);
636 break;
637 }
638
639 /* If a delivery attempt is required, spin off a new process to handle it.
640 If we are not root, we have to re-exec exim unless deliveries are being
641 done unprivileged. */
642
643 else if ( (!f.queue_only_policy || f.queue_smtp)
644 && !f.deliver_freeze)
645 {
646 pid_t dpid;
647
648 /* Before forking, ensure that the C output buffer is flushed. Otherwise
649 anything that it in it will get duplicated, leading to duplicate copies
650 of the pending output. */
651
652 mac_smtp_fflush();
653
654 if ((dpid = fork()) == 0)
655 {
656 (void)fclose(smtp_in);
657 (void)fclose(smtp_out);
658
659 /* Don't ever molest the parent's SSL connection, but do clean up
660 the data structures if necessary. */
661
662 #ifndef DISABLE_TLS
663 tls_close(NULL, TLS_NO_SHUTDOWN);
664 #endif
665
666 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
667
668 signal(SIGHUP, SIG_DFL);
669 signal(SIGCHLD, SIG_DFL);
670 signal(SIGTERM, SIG_DFL);
671
672 if (geteuid() != root_uid && !deliver_drop_privilege)
673 {
674 signal(SIGALRM, SIG_DFL);
675 delivery_re_exec(CEE_EXEC_PANIC);
676 /* Control does not return here. */
677 }
678
679 /* No need to re-exec; SIGALRM remains set to the default handler */
680
681 (void) deliver_message(message_id, FALSE, FALSE);
682 search_tidyup();
683 exim_underbar_exit(EXIT_SUCCESS);
684 }
685
686 if (dpid > 0)
687 {
688 release_cutthrough_connection(US"passed for delivery");
689 DEBUG(D_any) debug_printf("forked delivery process %d\n", (int)dpid);
690 }
691 else
692 {
693 cancel_cutthrough_connection(TRUE, US"delivery fork failed");
694 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: delivery process fork "
695 "failed: %s", strerror(errno));
696 }
697 }
698 }
699 }
700
701
702 /* Carrying on in the parent daemon process... Can't do much if the fork
703 failed. Otherwise, keep count of the number of accepting processes and
704 remember the pid for ticking off when the child completes. */
705
706 if (pid < 0)
707 never_error(US"daemon: accept process fork failed", US"Fork failed", errno);
708 else
709 {
710 for (int i = 0; i < smtp_accept_max; ++i)
711 if (smtp_slots[i].pid <= 0)
712 {
713 smtp_slots[i].pid = pid;
714 /* Connection closes come asyncronously, so we cannot stack this store */
715 if (smtp_accept_max_per_host)
716 smtp_slots[i].host_address = string_copy_malloc(sender_host_address);
717 smtp_accept_count++;
718 break;
719 }
720 DEBUG(D_any) debug_printf("%d SMTP accept process%s running\n",
721 smtp_accept_count, smtp_accept_count == 1 ? "" : "es");
722 }
723
724 /* Get here via goto in error cases */
725
726 ERROR_RETURN:
727
728 /* Close the streams associated with the socket which will also close the
729 socket fds in this process. We can't do anything if fclose() fails, but
730 logging brings it to someone's attention. However, "connection reset by peer"
731 isn't really a problem, so skip that one. On Solaris, a dropped connection can
732 manifest itself as a broken pipe, so drop that one too. If the streams don't
733 exist, something went wrong while setting things up. Make sure the socket
734 descriptors are closed, in order to drop the connection. */
735
736 if (smtp_out)
737 {
738 if (fclose(smtp_out) != 0 && errno != ECONNRESET && errno != EPIPE)
739 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_out) failed: %s",
740 strerror(errno));
741 smtp_out = NULL;
742 }
743 else (void)close(accept_socket);
744
745 if (smtp_in)
746 {
747 if (fclose(smtp_in) != 0 && errno != ECONNRESET && errno != EPIPE)
748 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_in) failed: %s",
749 strerror(errno));
750 smtp_in = NULL;
751 }
752 else (void)close(dup_accept_socket);
753
754 /* Release any store used in this process, including the store used for holding
755 the incoming host address and an expanded active_hostname. */
756
757 log_close_all();
758 interface_address =
759 sender_host_address = NULL;
760 store_reset(reset_point);
761 sender_host_address = NULL;
762 }
763
764
765
766
767 /*************************************************
768 * Check wildcard listen special cases *
769 *************************************************/
770
771 /* This function is used when binding and listening on lists of addresses and
772 ports. It tests for special cases of wildcard listening, when IPv4 and IPv6
773 sockets may interact in different ways in different operating systems. It is
774 passed an error number, the list of listening addresses, and the current
775 address. Two checks are available: for a previous wildcard IPv6 address, or for
776 a following wildcard IPv4 address, in both cases on the same port.
777
778 In practice, pairs of wildcard addresses should be adjacent in the address list
779 because they are sorted that way below.
780
781 Arguments:
782 eno the error number
783 addresses the list of addresses
784 ipa the current IP address
785 back if TRUE, check for previous wildcard IPv6 address
786 if FALSE, check for a following wildcard IPv4 address
787
788 Returns: TRUE or FALSE
789 */
790
791 static BOOL
792 check_special_case(int eno, ip_address_item *addresses, ip_address_item *ipa,
793 BOOL back)
794 {
795 ip_address_item *ipa2;
796
797 /* For the "back" case, if the failure was "address in use" for a wildcard IPv4
798 address, seek a previous IPv6 wildcard address on the same port. As it is
799 previous, it must have been successfully bound and be listening. Flag it as a
800 "6 including 4" listener. */
801
802 if (back)
803 {
804 if (eno != EADDRINUSE || ipa->address[0] != 0) return FALSE;
805 for (ipa2 = addresses; ipa2 != ipa; ipa2 = ipa2->next)
806 {
807 if (ipa2->address[1] == 0 && ipa2->port == ipa->port)
808 {
809 ipa2->v6_include_v4 = TRUE;
810 return TRUE;
811 }
812 }
813 }
814
815 /* For the "forward" case, if the current address is a wildcard IPv6 address,
816 we seek a following wildcard IPv4 address on the same port. */
817
818 else
819 {
820 if (ipa->address[0] != ':' || ipa->address[1] != 0) return FALSE;
821 for (ipa2 = ipa->next; ipa2 != NULL; ipa2 = ipa2->next)
822 if (ipa2->address[0] == 0 && ipa->port == ipa2->port) return TRUE;
823 }
824
825 return FALSE;
826 }
827
828
829
830
831 /*************************************************
832 * Handle terminating subprocesses *
833 *************************************************/
834
835 /* Handle the termination of child processes. Theoretically, this need be done
836 only when sigchld_seen is TRUE, but rumour has it that some systems lose
837 SIGCHLD signals at busy times, so to be on the safe side, this function is
838 called each time round. It shouldn't be too expensive.
839
840 Arguments: none
841 Returns: nothing
842 */
843
844 static void
845 handle_ending_processes(void)
846 {
847 int status;
848 pid_t pid;
849
850 while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
851 {
852 DEBUG(D_any)
853 {
854 debug_printf("child %d ended: status=0x%x\n", (int)pid, status);
855 #ifdef WCOREDUMP
856 if (WIFEXITED(status))
857 debug_printf(" normal exit, %d\n", WEXITSTATUS(status));
858 else if (WIFSIGNALED(status))
859 debug_printf(" signal exit, signal %d%s\n", WTERMSIG(status),
860 WCOREDUMP(status) ? " (core dumped)" : "");
861 #endif
862 }
863
864 /* If it's a listening daemon for which we are keeping track of individual
865 subprocesses, deal with an accepting process that has terminated. */
866
867 if (smtp_slots)
868 {
869 int i;
870 for (i = 0; i < smtp_accept_max; i++)
871 if (smtp_slots[i].pid == pid)
872 {
873 if (smtp_slots[i].host_address)
874 store_free(smtp_slots[i].host_address);
875 smtp_slots[i] = empty_smtp_slot;
876 if (--smtp_accept_count < 0) smtp_accept_count = 0;
877 DEBUG(D_any) debug_printf("%d SMTP accept process%s now running\n",
878 smtp_accept_count, (smtp_accept_count == 1)? "" : "es");
879 break;
880 }
881 if (i < smtp_accept_max) continue; /* Found an accepting process */
882 }
883
884 /* If it wasn't an accepting process, see if it was a queue-runner
885 process that we are tracking. */
886
887 if (queue_pid_slots)
888 {
889 int max = atoi(CS expand_string(queue_run_max));
890 for (int i = 0; i < max; i++)
891 if (queue_pid_slots[i] == pid)
892 {
893 queue_pid_slots[i] = 0;
894 if (--queue_run_count < 0) queue_run_count = 0;
895 DEBUG(D_any) debug_printf("%d queue-runner process%s now running\n",
896 queue_run_count, (queue_run_count == 1)? "" : "es");
897 break;
898 }
899 }
900 }
901 }
902
903
904
905 static void
906 set_pid_file_path(void)
907 {
908 if (override_pid_file_path)
909 pid_file_path = override_pid_file_path;
910
911 if (!*pid_file_path)
912 pid_file_path = string_sprintf("%s/exim-daemon.pid", spool_directory);
913 }
914
915
916 /* Remove the daemon's pidfile. Note: runs with root privilege,
917 as a direct child of the daemon. Does not return. */
918
919 void
920 delete_pid_file(void)
921 {
922 uschar * daemon_pid = string_sprintf("%d\n", (int)getppid());
923 FILE * f;
924
925 set_pid_file_path();
926 if ((f = Ufopen(pid_file_path, "rb")))
927 {
928 if ( fgets(CS big_buffer, big_buffer_size, f)
929 && Ustrcmp(daemon_pid, big_buffer) == 0
930 )
931 if (Uunlink(pid_file_path) == 0)
932 {
933 DEBUG(D_any)
934 debug_printf("%s unlink: %s\n", pid_file_path, strerror(errno));
935 }
936 else
937 DEBUG(D_any)
938 debug_printf("unlinked %s\n", pid_file_path);
939 fclose(f);
940 }
941 else
942 DEBUG(D_any)
943 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
944 pid_file_path));
945 exim_exit(EXIT_SUCCESS, US"pid file remover");
946 }
947
948
949 /* Called by the daemon; exec a child to get the pid file deleted
950 since we may require privs for the containing directory */
951
952 static void
953 daemon_die(void)
954 {
955 int pid;
956
957 if (daemon_notifier_fd >= 0)
958 {
959 close(daemon_notifier_fd);
960 daemon_notifier_fd = -1;
961 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
962 {
963 uschar * s = string_sprintf("%s/%s", spool_directory, NOTIFIER_SOCKET_NAME);
964 DEBUG(D_any) debug_printf("unlinking notifier socket %s\n", s);
965 Uunlink(s);
966 }
967 #endif
968 }
969
970 if (f.running_in_test_harness || write_pid)
971 {
972 if ((pid = fork()) == 0)
973 {
974 if (override_pid_file_path)
975 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 3,
976 "-oP", override_pid_file_path, "-oPX");
977 else
978 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 1, "-oPX");
979
980 /* Control never returns here. */
981 }
982 if (pid > 0)
983 child_close(pid, 1);
984 }
985 exim_exit(EXIT_SUCCESS, US"daemon");
986 }
987
988
989 /*************************************************
990 * Listener socket for local work prompts *
991 *************************************************/
992
993 static void
994 daemon_notifier_socket(void)
995 {
996 int fd;
997 const uschar * where;
998 struct sockaddr_un sa_un = {.sun_family = AF_UNIX};
999 int len;
1000
1001 DEBUG(D_any) debug_printf("creating notifier socket ");
1002
1003 #ifdef SOCK_CLOEXEC
1004 if ((fd = socket(PF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0)
1005 { where = US"socket"; goto bad; }
1006 #else
1007 if ((fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0)
1008 { where = US"socket"; goto bad; }
1009 (void)fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
1010 #endif
1011
1012 #ifdef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1013 sa_un.sun_path[0] = 0; /* Abstract local socket addr - Linux-specific? */
1014 len = offsetof(struct sockaddr_un, sun_path) + 1
1015 + snprintf(sa_un.sun_path+1, sizeof(sa_un.sun_path)-1, "%s", NOTIFIER_SOCKET_NAME);
1016 DEBUG(D_any) debug_printf("@%s\n", sa_un.sun_path+1);
1017 #else /* filesystem-visible and persistent; will neeed removal */
1018 len = offsetof(struct sockaddr_un, sun_path)
1019 + snprintf(sa_un.sun_path, sizeof(sa_un.sun_path), "%s/%s",
1020 spool_directory, NOTIFIER_SOCKET_NAME);
1021 DEBUG(D_any) debug_printf("%s\n", sa_un.sun_path);
1022 #endif
1023
1024 if (bind(fd, (const struct sockaddr *)&sa_un, len) < 0)
1025 { where = US"bind"; goto bad; }
1026
1027 #ifdef SO_PASSCRED /* Linux */
1028 if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0)
1029 { where = US"SO_PASSCRED"; goto bad2; }
1030 #elif defined(LOCAL_CREDS) /* FreeBSD-ish */
1031 if (setsockopt(fd, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
1032 { where = US"LOCAL_CREDS"; goto bad2; }
1033 #endif
1034
1035 /* debug_printf("%s: fd %d\n", __FUNCTION__, fd); */
1036 daemon_notifier_fd = fd;
1037 return;
1038
1039 bad2:
1040 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1041 Uunlink(sa_un.sun_path);
1042 #endif
1043 bad:
1044 log_write(0, LOG_MAIN|LOG_PANIC, "%s %s: %s",
1045 __FUNCTION__, where, strerror(errno));
1046 close(fd);
1047 return;
1048 }
1049
1050
1051 static uschar queuerun_msgid[MESSAGE_ID_LENGTH+1];
1052
1053 /* Return TRUE if a sigalrm should be emulated */
1054 static BOOL
1055 daemon_notification(void)
1056 {
1057 uschar buf[256], cbuf[256];
1058 struct sockaddr_un sa_un;
1059 struct iovec iov = {.iov_base = buf, .iov_len = sizeof(buf)-1};
1060 struct msghdr msg = { .msg_name = &sa_un,
1061 .msg_namelen = sizeof(sa_un),
1062 .msg_iov = &iov,
1063 .msg_iovlen = 1,
1064 .msg_control = cbuf,
1065 .msg_controllen = sizeof(cbuf)
1066 };
1067 ssize_t sz;
1068 struct cmsghdr * cp;
1069
1070 buf[sizeof(buf)-1] = 0;
1071 if ((sz = recvmsg(daemon_notifier_fd, &msg, 0)) <= 0) return FALSE;
1072 if (sz >= sizeof(buf)) return FALSE;
1073
1074 #ifdef notdef
1075 debug_printf("addrlen %d\n", msg.msg_namelen);
1076 #endif
1077 DEBUG(D_queue_run) debug_printf("%s from addr '%s%.*s'\n", __FUNCTION__,
1078 *sa_un.sun_path ? "" : "@",
1079 (int)msg.msg_namelen - (*sa_un.sun_path ? 0 : 1),
1080 sa_un.sun_path + (*sa_un.sun_path ? 0 : 1));
1081
1082 /* Refuse to handle the item unless the peer has good credentials */
1083 #ifdef SCM_CREDENTIALS
1084 # define EXIM_SCM_CR_TYPE SCM_CREDENTIALS
1085 #elif defined(LOCAL_CREDS) && defined(SCM_CREDS)
1086 # define EXIM_SCM_CR_TYPE SCM_CREDS
1087 #else
1088 /* The OS has no way to get the creds of the caller (for a unix/datagram socket.
1089 Punt; don't try to check. */
1090 #endif
1091
1092 #ifdef EXIM_SCM_CR_TYPE
1093 for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg);
1094 cp;
1095 cp = CMSG_NXTHDR(&msg, cp))
1096 if (cp->cmsg_level == SOL_SOCKET && cp->cmsg_type == EXIM_SCM_CR_TYPE)
1097 {
1098 # ifdef SCM_CREDENTIALS /* Linux */
1099 struct ucred * cr = (struct ucred *) CMSG_DATA(cp);
1100 if (cr->uid && cr->uid != exim_uid)
1101 {
1102 DEBUG(D_queue_run) debug_printf("%s: sender creds pid %d uid %d gid %d\n",
1103 __FUNCTION__, (int)cr->pid, (int)cr->uid, (int)cr->gid);
1104 return FALSE;
1105 }
1106 # elif defined(LOCAL_CREDS) /* BSD-ish */
1107 struct sockcred * cr = (struct sockcred *) CMSG_DATA(cp);
1108 if (cr->sc_uid && cr->sc_uid != exim_uid)
1109 {
1110 DEBUG(D_queue_run) debug_printf("%s: sender creds pid ??? uid %d gid %d\n",
1111 __FUNCTION__, (int)cr->sc_uid, (int)cr->sc_gid);
1112 return FALSE;
1113 }
1114 # endif
1115 break;
1116 }
1117 #endif
1118
1119 buf[sz] = 0;
1120 switch (buf[0])
1121 {
1122 #ifdef EXPERIMENTAL_QUEUE_RAMP
1123 case NOTIFY_MSG_QRUN:
1124 /* this should be a message_id */
1125 DEBUG(D_queue_run)
1126 debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1);
1127 memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1);
1128 return TRUE;
1129 #endif /*EXPERIMENTAL_QUEUE_RAMP*/
1130
1131 case NOTIFY_QUEUE_SIZE_REQ:
1132 {
1133 uschar buf[16];
1134 int len = snprintf(CS buf, sizeof(buf), "%u", queue_count_cached());
1135
1136 DEBUG(D_queue_run)
1137 debug_printf("%s: queue size request: %s\n", __FUNCTION__, buf);
1138
1139 if (sendto(daemon_notifier_fd, buf, len, 0,
1140 (const struct sockaddr *)&sa_un, msg.msg_namelen) < 0)
1141 log_write(0, LOG_MAIN|LOG_PANIC,
1142 "%s: sendto: %s\n", __FUNCTION__, strerror(errno));
1143 return FALSE;
1144 }
1145 }
1146 return FALSE;
1147 }
1148
1149
1150 /*************************************************
1151 * Exim Daemon Mainline *
1152 *************************************************/
1153
1154 /* The daemon can do two jobs, either of which is optional:
1155
1156 (1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1157 each one. This is requested by the -bd option, with -oX specifying the SMTP
1158 port on which to listen (for testing).
1159
1160 (2) Spawns a queue-running process every so often. This is controlled by the
1161 -q option with a an interval time. (If no time is given, a single queue run
1162 is done from the main function, and control doesn't get here.)
1163
1164 Root privilege is required in order to attach to port 25. Some systems require
1165 it when calling socket() rather than bind(). To cope with all cases, we run as
1166 root for both socket() and bind(). Some systems also require root in order to
1167 write to the pid file directory. This function must therefore be called as root
1168 if it is to work properly in all circumstances. Once the socket is bound and
1169 the pid file written, root privilege is given up if there is an exim uid.
1170
1171 There are no arguments to this function, and it never returns. */
1172
1173 void
1174 daemon_go(void)
1175 {
1176 struct passwd *pw;
1177 int *listen_sockets = NULL;
1178 int listen_socket_count = 0;
1179 ip_address_item *addresses = NULL;
1180 time_t last_connection_time = (time_t)0;
1181 int local_queue_run_max = atoi(CS expand_string(queue_run_max));
1182
1183 /* If any debugging options are set, turn on the D_pid bit so that all
1184 debugging lines get the pid added. */
1185
1186 DEBUG(D_any|D_v) debug_selector |= D_pid;
1187
1188 if (f.inetd_wait_mode)
1189 {
1190 listen_socket_count = 1;
1191 listen_sockets = store_get(sizeof(int), FALSE);
1192 (void) close(3);
1193 if (dup2(0, 3) == -1)
1194 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1195 "failed to dup inetd socket safely away: %s", strerror(errno));
1196
1197 listen_sockets[0] = 3;
1198 (void) close(0);
1199 (void) close(1);
1200 (void) close(2);
1201 exim_nullstd();
1202
1203 if (debug_file == stderr)
1204 {
1205 /* need a call to log_write before call to open debug_file, so that
1206 log.c:file_path has been initialised. This is unfortunate. */
1207 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1208
1209 fclose(debug_file);
1210 debug_file = NULL;
1211 exim_nullstd(); /* re-open fd2 after we just closed it again */
1212 debug_logging_activate(US"-wait", NULL);
1213 }
1214
1215 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1216
1217 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1218 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1219
1220 if (tcp_nodelay)
1221 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1222 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1223 strerror(errno));
1224 }
1225
1226
1227 if (f.inetd_wait_mode || f.daemon_listen)
1228 {
1229 /* If any option requiring a load average to be available during the
1230 reception of a message is set, call os_getloadavg() while we are root
1231 for those OS for which this is necessary the first time it is called (in
1232 order to perform an "open" on the kernel memory file). */
1233
1234 #ifdef LOAD_AVG_NEEDS_ROOT
1235 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1236 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1237 (void)os_getloadavg();
1238 #endif
1239 }
1240
1241
1242 /* Do the preparation for setting up a listener on one or more interfaces, and
1243 possible on various ports. This is controlled by the combination of
1244 local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1245 (which is a list of default ports to use for those items in local_interfaces
1246 that do not specify a port). The -oX command line option can be used to
1247 override one or both of these options.
1248
1249 If local_interfaces is not set, the default is to listen on all interfaces.
1250 When it is set, it can include "all IPvx interfaces" as an item. This is useful
1251 when different ports are in use.
1252
1253 It turns out that listening on all interfaces is messy in an IPv6 world,
1254 because several different implementation approaches have been taken. This code
1255 is now supposed to work with all of them. The point of difference is whether an
1256 IPv6 socket that is listening on all interfaces will receive incoming IPv4
1257 calls or not. We also have to cope with the case when IPv6 libraries exist, but
1258 there is no IPv6 support in the kernel.
1259
1260 . On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1261 addresses. However, if an IPv4 socket is also listening on all interfaces,
1262 calls are directed to the appropriate socket.
1263
1264 . On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1265 give them as mapped addresses, but an attempt also to listen on an IPv4
1266 socket on all interfaces causes an error.
1267
1268 . On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1269 two sockets if you want to accept both kinds of call.
1270
1271 . FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1272 can be turned off, to make it behave like the versions of Linux described
1273 above.
1274
1275 . I heard a report that the USAGI IPv6 stack for Linux has implemented
1276 IPV6_V6ONLY.
1277
1278 So, what we do when IPv6 is supported is as follows:
1279
1280 (1) After it is set up, the list of interfaces is scanned for wildcard
1281 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1282 port, the list is re-arranged so that they are together, with the IPv6
1283 wildcard first.
1284
1285 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1286 carry on if an IPv4 wildcard socket for the same port follows later in the
1287 list. This allows Exim to carry on in the case when the kernel has no IPv6
1288 support.
1289
1290 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1291 option is defined. However, if setting fails, carry on regardless (but log
1292 the incident).
1293
1294 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1295 error.
1296
1297 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1298 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1299 port (which must have succeeded or we wouldn't have got this far), we
1300 assume we are in the situation where just a single socket is permitted,
1301 and ignore the error.
1302
1303 Phew!
1304
1305 The preparation code decodes options and sets up the relevant data. We do this
1306 first, so that we can return non-zero if there are any syntax errors, and also
1307 write to stderr. */
1308
1309 if (f.daemon_listen && !f.inetd_wait_mode)
1310 {
1311 int *default_smtp_port;
1312 int sep;
1313 int pct = 0;
1314 uschar *s;
1315 const uschar * list;
1316 uschar *local_iface_source = US"local_interfaces";
1317 ip_address_item *ipa;
1318 ip_address_item **pipa;
1319
1320 /* If -oX was used, disable the writing of a pid file unless -oP was
1321 explicitly used to force it. Then scan the string given to -oX. Any items
1322 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1323 Any other items are used to override local_interfaces. */
1324
1325 if (override_local_interfaces)
1326 {
1327 gstring * new_smtp_port = NULL;
1328 gstring * new_local_interfaces = NULL;
1329
1330 if (!override_pid_file_path) write_pid = FALSE;
1331
1332 list = override_local_interfaces;
1333 sep = 0;
1334 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1335 {
1336 uschar joinstr[4];
1337 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
1338
1339 if (!*gp)
1340 {
1341 joinstr[0] = sep;
1342 joinstr[1] = ' ';
1343 *gp = string_catn(*gp, US"<", 1);
1344 }
1345
1346 *gp = string_catn(*gp, joinstr, 2);
1347 *gp = string_cat (*gp, s);
1348 }
1349
1350 if (new_smtp_port)
1351 {
1352 daemon_smtp_port = string_from_gstring(new_smtp_port);
1353 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1354 daemon_smtp_port);
1355 }
1356
1357 if (new_local_interfaces)
1358 {
1359 local_interfaces = string_from_gstring(new_local_interfaces);
1360 local_iface_source = US"-oX data";
1361 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1362 local_interfaces);
1363 }
1364 }
1365
1366 /* Create a list of default SMTP ports, to be used if local_interfaces
1367 contains entries without explicit ports. First count the number of ports, then
1368 build a translated list in a vector. */
1369
1370 list = daemon_smtp_port;
1371 sep = 0;
1372 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1373 pct++;
1374 default_smtp_port = store_get((pct+1) * sizeof(int), FALSE);
1375 list = daemon_smtp_port;
1376 sep = 0;
1377 for (pct = 0;
1378 (s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size));
1379 pct++)
1380 {
1381 if (isdigit(*s))
1382 {
1383 uschar *end;
1384 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1385 if (end != s + Ustrlen(s))
1386 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1387 }
1388 else
1389 {
1390 struct servent *smtp_service = getservbyname(CS s, "tcp");
1391 if (!smtp_service)
1392 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1393 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1394 }
1395 }
1396 default_smtp_port[pct] = 0;
1397
1398 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1399
1400 list = tls_in.on_connect_ports;
1401 sep = 0;
1402 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1403 if (!isdigit(*s))
1404 {
1405 gstring * g = NULL;
1406
1407 list = tls_in.on_connect_ports;
1408 tls_in.on_connect_ports = NULL;
1409 sep = 0;
1410 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1411 {
1412 if (!isdigit(*s))
1413 {
1414 struct servent * smtp_service = getservbyname(CS s, "tcp");
1415 if (!smtp_service)
1416 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1417 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
1418 }
1419 g = string_append_listele(g, ':', s);
1420 }
1421 if (g)
1422 tls_in.on_connect_ports = g->s;
1423 break;
1424 }
1425
1426 /* Create the list of local interfaces, possibly with ports included. This
1427 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1428 values are converted below. */
1429
1430 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1431
1432 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1433 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1434 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1435 anyway, but we need to know which are the wildcard addresses, and the shorter
1436 strings are neater.
1437
1438 In the same scan, fill in missing port numbers from the default list. When
1439 there is more than one item in the list, extra items are created. */
1440
1441 for (ipa = addresses; ipa; ipa = ipa->next)
1442 {
1443 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1444 ipa->address[0] = 0;
1445 else if (Ustrcmp(ipa->address, "::0") == 0)
1446 {
1447 ipa->address[0] = ':';
1448 ipa->address[1] = 0;
1449 }
1450
1451 if (ipa->port > 0) continue;
1452
1453 if (daemon_smtp_port[0] <= 0)
1454 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1455 "%s and daemon_smtp_port is unset; cannot start daemon",
1456 ipa->address[0] == 0 ? US"\"all IPv4\"" :
1457 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
1458
1459 ipa->port = default_smtp_port[0];
1460 for (int i = 1; default_smtp_port[i] > 0; i++)
1461 {
1462 ip_address_item *new = store_get(sizeof(ip_address_item), FALSE);
1463
1464 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1465 new->port = default_smtp_port[i];
1466 new->next = ipa->next;
1467 ipa->next = new;
1468 ipa = new;
1469 }
1470 }
1471
1472 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1473 wildcard for the same port, ensure that (a) they are together and (b) the
1474 IPv6 address comes first. This makes handling the messy features easier, and
1475 also simplifies the construction of the "daemon started" log line. */
1476
1477 pipa = &addresses;
1478 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
1479 {
1480 ip_address_item *ipa2;
1481
1482 /* Handle an IPv4 wildcard */
1483
1484 if (ipa->address[0] == 0)
1485 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1486 {
1487 ip_address_item *ipa3 = ipa2->next;
1488 if (ipa3->address[0] == ':' &&
1489 ipa3->address[1] == 0 &&
1490 ipa3->port == ipa->port)
1491 {
1492 ipa2->next = ipa3->next;
1493 ipa3->next = ipa;
1494 *pipa = ipa3;
1495 break;
1496 }
1497 }
1498
1499 /* Handle an IPv6 wildcard. */
1500
1501 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
1502 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1503 {
1504 ip_address_item *ipa3 = ipa2->next;
1505 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1506 {
1507 ipa2->next = ipa3->next;
1508 ipa3->next = ipa->next;
1509 ipa->next = ipa3;
1510 ipa = ipa3;
1511 break;
1512 }
1513 }
1514 }
1515
1516 /* Get a vector to remember all the sockets in */
1517
1518 for (ipa = addresses; ipa; ipa = ipa->next)
1519 listen_socket_count++;
1520 listen_sockets = store_get(sizeof(int) * listen_socket_count, FALSE);
1521
1522 } /* daemon_listen but not inetd_wait_mode */
1523
1524 if (f.daemon_listen)
1525 {
1526
1527 /* Do a sanity check on the max connects value just to save us from getting
1528 a huge amount of store. */
1529
1530 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1531
1532 /* There's no point setting smtp_accept_queue unless it is less than the max
1533 connects limit. The configuration reader ensures that the max is set if the
1534 queue-only option is set. */
1535
1536 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1537
1538 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1539 track of them for total number and queue/host limits. */
1540
1541 if (smtp_accept_max > 0)
1542 {
1543 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), FALSE);
1544 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
1545 }
1546 }
1547
1548 /* The variable background_daemon is always false when debugging, but
1549 can also be forced false in order to keep a non-debugging daemon in the
1550 foreground. If background_daemon is true, close all open file descriptors that
1551 we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1552 do this for inetd_wait mode.
1553
1554 This is protection against any called functions (in libraries, or in
1555 Perl, or whatever) that think they can write to stderr (or stdout). Before this
1556 was added, it was quite likely that an SMTP connection would use one of these
1557 file descriptors, in which case writing random stuff to it caused chaos.
1558
1559 Then disconnect from the controlling terminal, Most modern Unixes seem to have
1560 setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1561 setsid() can be #defined as a no-op, or as something else. */
1562
1563 if (f.background_daemon || f.inetd_wait_mode)
1564 {
1565 log_close_all(); /* Just in case anything was logged earlier */
1566 search_tidyup(); /* Just in case any were used in reading the config. */
1567 (void)close(0); /* Get rid of stdin/stdout/stderr */
1568 (void)close(1);
1569 (void)close(2);
1570 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
1571 log_stderr = NULL; /* So no attempt to copy paniclog output */
1572 }
1573
1574 if (f.background_daemon)
1575 {
1576 /* If the parent process of this one has pid == 1, we are re-initializing the
1577 daemon as the result of a SIGHUP. In this case, there is no need to do
1578 anything, because the controlling terminal has long gone. Otherwise, fork, in
1579 case current process is a process group leader (see 'man setsid' for an
1580 explanation) before calling setsid(). */
1581
1582 if (getppid() != 1)
1583 {
1584 pid_t pid = fork();
1585 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1586 "fork() failed when starting daemon: %s", strerror(errno));
1587 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1588 (void)setsid(); /* release controlling terminal */
1589 }
1590 }
1591
1592 /* We are now in the disconnected, daemon process (unless debugging). Set up
1593 the listening sockets if required. */
1594
1595 daemon_notifier_socket();
1596
1597 if (f.daemon_listen && !f.inetd_wait_mode)
1598 {
1599 int sk;
1600 ip_address_item *ipa;
1601
1602 /* For each IP address, create a socket, bind it to the appropriate port, and
1603 start listening. See comments above about IPv6 sockets that may or may not
1604 accept IPv4 calls when listening on all interfaces. We also have to cope with
1605 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1606 listening, provided a wildcard IPv4 socket for the same port follows. */
1607
1608 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1609 {
1610 BOOL wildcard;
1611 ip_address_item *ipa2;
1612 int af;
1613
1614 if (Ustrchr(ipa->address, ':') != NULL)
1615 {
1616 af = AF_INET6;
1617 wildcard = ipa->address[1] == 0;
1618 }
1619 else
1620 {
1621 af = AF_INET;
1622 wildcard = ipa->address[0] == 0;
1623 }
1624
1625 if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0)
1626 {
1627 if (check_special_case(0, addresses, ipa, FALSE))
1628 {
1629 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1630 "listening (%s): will use IPv4", strerror(errno));
1631 goto SKIP_SOCKET;
1632 }
1633 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1634 (af == AF_INET6)? '6' : '4', strerror(errno));
1635 }
1636
1637 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1638 available. Just log failure (can get protocol not available, just like
1639 socket creation can). */
1640
1641 #ifdef IPV6_V6ONLY
1642 if (af == AF_INET6 && wildcard &&
1643 setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, CS (&on),
1644 sizeof(on)) < 0)
1645 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1646 "socket failed (%s): carrying on without it", strerror(errno));
1647 #endif /* IPV6_V6ONLY */
1648
1649 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1650 is being handled. Without this, a connection will prevent reuse of the
1651 smtp port for listening. */
1652
1653 if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR,
1654 US (&on), sizeof(on)) < 0)
1655 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1656 "failed when starting daemon: %s", strerror(errno));
1657
1658 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1659 disable this because it breaks some broken clients. */
1660
1661 if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY,
1662 US (&on), sizeof(on));
1663
1664 /* Now bind the socket to the required port; if Exim is being restarted
1665 it may not always be possible to bind immediately, even with SO_REUSEADDR
1666 set, so try 10 times, waiting between each try. After 10 failures, we give
1667 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1668 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1669 address for the same port, ignore the error on the grounds that we must be
1670 in a system where the IPv6 socket accepts both kinds of call. This is
1671 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1672 listen() stage instead. */
1673
1674 #ifdef TCP_FASTOPEN
1675 f.tcp_fastopen_ok = TRUE;
1676 #endif
1677 for(;;)
1678 {
1679 uschar *msg, *addr;
1680 if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break;
1681 if (check_special_case(errno, addresses, ipa, TRUE))
1682 {
1683 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1684 "listen() success; EADDRINUSE ignored\n");
1685 (void)close(listen_sockets[sk]);
1686 goto SKIP_SOCKET;
1687 }
1688 msg = US strerror(errno);
1689 addr = wildcard
1690 ? af == AF_INET6
1691 ? US"(any IPv6)"
1692 : US"(any IPv4)"
1693 : ipa->address;
1694 if (daemon_startup_retries <= 0)
1695 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1696 "socket bind() to port %d for address %s failed: %s: "
1697 "daemon abandoned", ipa->port, addr, msg);
1698 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
1699 "failed: %s: waiting %s before trying again (%d more %s)",
1700 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1701 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1702 daemon_startup_retries--;
1703 sleep(daemon_startup_sleep);
1704 }
1705
1706 DEBUG(D_any)
1707 if (wildcard)
1708 debug_printf("listening on all interfaces (IPv%c) port %d\n",
1709 af == AF_INET6 ? '6' : '4', ipa->port);
1710 else
1711 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
1712
1713 #if defined(TCP_FASTOPEN) && !defined(__APPLE__)
1714 if ( f.tcp_fastopen_ok
1715 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1716 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
1717 {
1718 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1719 f.tcp_fastopen_ok = FALSE;
1720 }
1721 #endif
1722
1723 /* Start listening on the bound socket, establishing the maximum backlog of
1724 connections that is allowed. On success, continue to the next address. */
1725
1726 if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0)
1727 {
1728 #if defined(TCP_FASTOPEN) && defined(__APPLE__)
1729 if ( f.tcp_fastopen_ok
1730 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1731 &on, sizeof(on)))
1732 {
1733 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1734 f.tcp_fastopen_ok = FALSE;
1735 }
1736 #endif
1737 continue;
1738 }
1739
1740 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1741 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1742 and there was a previous successful IPv6 wildcard listen on the same port,
1743 we want to ignore the error on the grounds that we must be in a system
1744 where the IPv6 socket accepts both kinds of call. */
1745
1746 if (!check_special_case(errno, addresses, ipa, TRUE))
1747 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
1748 wildcard
1749 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
1750 strerror(errno));
1751
1752 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1753 "listen() success; EADDRINUSE ignored\n");
1754 (void)close(listen_sockets[sk]);
1755
1756 /* Come here if there has been a problem with the socket which we
1757 are going to ignore. We remove the address from the chain, and back up the
1758 counts. */
1759
1760 SKIP_SOCKET:
1761 sk--; /* Back up the count */
1762 listen_socket_count--; /* Reduce the total */
1763 if (ipa == addresses) addresses = ipa->next; else
1764 {
1765 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1766 ipa2->next = ipa->next;
1767 ipa = ipa2;
1768 }
1769 } /* End of bind/listen loop for each address */
1770 } /* End of setup for listening */
1771
1772
1773 /* If we are not listening, we want to write a pid file only if -oP was
1774 explicitly given. */
1775
1776 else if (!override_pid_file_path)
1777 write_pid = FALSE;
1778
1779 /* Write the pid to a known file for assistance in identification, if required.
1780 We do this before giving up root privilege, because on some systems it is
1781 necessary to be root in order to write into the pid file directory. There's
1782 nothing to stop multiple daemons running, as long as no more than one listens
1783 on a given TCP/IP port on the same interface(s). However, in these
1784 circumstances it gets far too complicated to mess with pid file names
1785 automatically. Consequently, Exim 4 writes a pid file only
1786
1787 (a) When running in the test harness, or
1788 (b) When -bd is used and -oX is not used, or
1789 (c) When -oP is used to supply a path.
1790
1791 The variable daemon_write_pid is used to control this. */
1792
1793 if (f.running_in_test_harness || write_pid)
1794 {
1795 FILE *f;
1796
1797 set_pid_file_path();
1798 if ((f = modefopen(pid_file_path, "wb", 0644)))
1799 {
1800 (void)fprintf(f, "%d\n", (int)getpid());
1801 (void)fclose(f);
1802 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1803 }
1804 else
1805 DEBUG(D_any)
1806 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
1807 pid_file_path));
1808 }
1809
1810 /* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1811
1812 sighup_seen = FALSE;
1813 signal(SIGHUP, sighup_handler);
1814
1815 /* Give up root privilege at this point (assuming that exim_uid and exim_gid
1816 are not root). The third argument controls the running of initgroups().
1817 Normally we do this, in order to set up the groups for the Exim user. However,
1818 if we are not root at this time - some odd installations run that way - we
1819 cannot do this. */
1820
1821 exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1822
1823 /* Update the originator_xxx fields so that received messages as listed as
1824 coming from Exim, not whoever started the daemon. */
1825
1826 originator_uid = exim_uid;
1827 originator_gid = exim_gid;
1828 originator_login = (pw = getpwuid(exim_uid))
1829 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
1830
1831 /* Get somewhere to keep the list of queue-runner pids if we are keeping track
1832 of them (and also if we are doing queue runs). */
1833
1834 if (queue_interval > 0 && local_queue_run_max > 0)
1835 {
1836 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t), FALSE);
1837 for (int i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
1838 }
1839
1840 /* Set up the handler for termination of child processes, and the one
1841 telling us to die. */
1842
1843 sigchld_seen = FALSE;
1844 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
1845
1846 sigterm_seen = FALSE;
1847 os_non_restarting_signal(SIGTERM, main_sigterm_handler);
1848
1849 /* If we are to run the queue periodically, pretend the alarm has just gone
1850 off. This will cause the first queue-runner to get kicked off straight away. */
1851
1852 sigalrm_seen = (queue_interval > 0);
1853
1854 /* Log the start up of a daemon - at least one of listening or queue running
1855 must be set up. */
1856
1857 if (f.inetd_wait_mode)
1858 {
1859 uschar *p = big_buffer;
1860
1861 if (inetd_wait_timeout >= 0)
1862 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
1863 else
1864 sprintf(CS p, "with no wait timeout");
1865
1866 log_write(0, LOG_MAIN,
1867 "exim %s daemon started: pid=%d, launched with listening socket, %s",
1868 version_string, getpid(), big_buffer);
1869 set_process_info("daemon(%s): pre-listening socket", version_string);
1870
1871 /* set up the timeout logic */
1872 sigalrm_seen = TRUE;
1873 }
1874
1875 else if (f.daemon_listen)
1876 {
1877 int smtp_ports = 0;
1878 int smtps_ports = 0;
1879 ip_address_item * ipa;
1880 uschar * p;
1881 uschar * qinfo = queue_interval > 0
1882 ? string_sprintf("-q%s", readconf_printtime(queue_interval))
1883 : US"no queue runs";
1884
1885 /* Build a list of listening addresses in big_buffer, but limit it to 10
1886 items. The style is for backwards compatibility.
1887
1888 It is now possible to have some ports listening for SMTPS (the old,
1889 deprecated protocol that starts TLS without using STARTTLS), and others
1890 listening for standard SMTP. Keep their listings separate. */
1891
1892 for (int j = 0, i; j < 2; j++)
1893 {
1894 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
1895 {
1896 /* First time round, look for SMTP ports; second time round, look for
1897 SMTPS ports. Build IP+port strings. */
1898
1899 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1900 {
1901 if (j == 0)
1902 smtp_ports++;
1903 else
1904 smtps_ports++;
1905
1906 /* Now the information about the port (and sometimes interface) */
1907
1908 if (ipa->address[0] == ':' && ipa->address[1] == 0)
1909 { /* v6 wildcard */
1910 if (ipa->next && ipa->next->address[0] == 0 &&
1911 ipa->next->port == ipa->port)
1912 {
1913 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
1914 (ipa = ipa->next)->log = NULL;
1915 }
1916 else if (ipa->v6_include_v4)
1917 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
1918 else
1919 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
1920 }
1921 else if (ipa->address[0] == 0) /* v4 wildcard */
1922 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
1923 else /* check for previously-seen IP */
1924 {
1925 ip_address_item * i2;
1926 for (i2 = addresses; i2 != ipa; i2 = i2->next)
1927 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
1928 && Ustrcmp(ipa->address, i2->address) == 0
1929 )
1930 { /* found; append port to list */
1931 for (p = i2->log; *p; ) p++; /* end of existing string */
1932 if (*--p == '}') *p = '\0'; /* drop EOL */
1933 while (isdigit(*--p)) ; /* char before port */
1934
1935 i2->log = *p == ':' /* no list yet? */
1936 ? string_sprintf("%.*s{%s,%d}",
1937 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
1938 : string_sprintf("%s,%d}", i2->log, ipa->port);
1939 ipa->log = NULL;
1940 break;
1941 }
1942 if (i2 == ipa) /* first-time IP */
1943 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
1944 }
1945 }
1946 }
1947 }
1948
1949 p = big_buffer;
1950 for (int j = 0, i; j < 2; j++)
1951 {
1952 /* First time round, look for SMTP ports; second time round, look for
1953 SMTPS ports. For the first one of each, insert leading text. */
1954
1955 if (j == 0)
1956 {
1957 if (smtp_ports > 0)
1958 p += sprintf(CS p, "SMTP on");
1959 }
1960 else
1961 if (smtps_ports > 0)
1962 p += sprintf(CS p, "%sSMTPS on",
1963 smtp_ports == 0 ? "" : " and for ");
1964
1965 /* Now the information about the port (and sometimes interface) */
1966
1967 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
1968 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1969 if (ipa->log)
1970 p += sprintf(CS p, "%s", ipa->log);
1971
1972 if (ipa)
1973 p += sprintf(CS p, " ...");
1974 }
1975
1976 log_write(0, LOG_MAIN,
1977 "exim %s daemon started: pid=%d, %s, listening for %s",
1978 version_string, getpid(), qinfo, big_buffer);
1979 set_process_info("daemon(%s): %s, listening for %s",
1980 version_string, qinfo, big_buffer);
1981 }
1982
1983 else
1984 {
1985 uschar * s = *queue_name
1986 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
1987 : string_sprintf("-q%s", readconf_printtime(queue_interval));
1988 log_write(0, LOG_MAIN,
1989 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
1990 version_string, getpid(), s);
1991 set_process_info("daemon(%s): %s, not listening", version_string, s);
1992 }
1993
1994 /* Do any work it might be useful to amortize over our children
1995 (eg: compile regex) */
1996
1997 dns_pattern_init();
1998 smtp_deliver_init(); /* Used for callouts */
1999
2000 #ifndef DISABLE_DKIM
2001 {
2002 # ifdef MEASURE_TIMING
2003 struct timeval t0;
2004 gettimeofday(&t0, NULL);
2005 # endif
2006 dkim_exim_init();
2007 # ifdef MEASURE_TIMING
2008 report_time_since(&t0, US"dkim_exim_init (delta)");
2009 # endif
2010 }
2011 #endif
2012
2013 #ifdef WITH_CONTENT_SCAN
2014 malware_init();
2015 #endif
2016 #ifdef SUPPORT_SPF
2017 spf_init();
2018 #endif
2019
2020 /* Close the log so it can be renamed and moved. In the few cases below where
2021 this long-running process writes to the log (always exceptional conditions), it
2022 closes the log afterwards, for the same reason. */
2023
2024 log_close_all();
2025
2026 DEBUG(D_any) debug_print_ids(US"daemon running with");
2027
2028 /* Any messages accepted via this route are going to be SMTP. */
2029
2030 smtp_input = TRUE;
2031
2032 #ifdef MEASURE_TIMING
2033 report_time_since(&timestamp_startup, US"daemon loop start"); /* testcase 0022 */
2034 #endif
2035
2036 /* Enter the never-ending loop... */
2037
2038 for (;;)
2039 {
2040 #if HAVE_IPV6
2041 struct sockaddr_in6 accepted;
2042 #else
2043 struct sockaddr_in accepted;
2044 #endif
2045
2046 EXIM_SOCKLEN_T len;
2047 pid_t pid;
2048
2049 if (sigterm_seen)
2050 daemon_die(); /* Does not return */
2051
2052 /* This code is placed first in the loop, so that it gets obeyed at the
2053 start, before the first wait, for the queue-runner case, so that the first
2054 one can be started immediately.
2055
2056 The other option is that we have an inetd wait timeout specified to -bw. */
2057
2058 if (sigalrm_seen)
2059 {
2060 if (inetd_wait_timeout > 0)
2061 {
2062 time_t resignal_interval = inetd_wait_timeout;
2063
2064 if (last_connection_time == (time_t)0)
2065 {
2066 DEBUG(D_any)
2067 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
2068 }
2069 else
2070 {
2071 time_t now = time(NULL);
2072 if (now == (time_t)-1)
2073 {
2074 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
2075 }
2076 else
2077 {
2078 if ((now - last_connection_time) >= inetd_wait_timeout)
2079 {
2080 DEBUG(D_any)
2081 debug_printf("inetd wait timeout %d expired, ending daemon\n",
2082 inetd_wait_timeout);
2083 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
2084 version_string);
2085 exit(EXIT_SUCCESS);
2086 }
2087 else
2088 {
2089 resignal_interval -= (now - last_connection_time);
2090 }
2091 }
2092 }
2093
2094 sigalrm_seen = FALSE;
2095 ALARM(resignal_interval);
2096 }
2097
2098 else
2099 {
2100 DEBUG(D_any) debug_printf("%s received\n",
2101 #ifdef EXPERIMENTAL_QUEUE_RAMP
2102 *queuerun_msgid ? "qrun notification" :
2103 #endif
2104 "SIGALRM");
2105
2106 /* Do a full queue run in a child process, if required, unless we already
2107 have enough queue runners on the go. If we are not running as root, a
2108 re-exec is required. */
2109
2110 if (queue_interval > 0 &&
2111 (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
2112 {
2113 if ((pid = fork()) == 0)
2114 {
2115 DEBUG(D_any) debug_printf("Starting queue-runner: pid %d\n",
2116 (int)getpid());
2117
2118 /* Disable debugging if it's required only for the daemon process. We
2119 leave the above message, because it ties up with the "child ended"
2120 debugging messages. */
2121
2122 if (f.debug_daemon) debug_selector = 0;
2123
2124 /* Close any open listening sockets in the child */
2125
2126 if (daemon_notifier_fd >= 0)
2127 (void) close(daemon_notifier_fd);
2128 for (int sk = 0; sk < listen_socket_count; sk++)
2129 (void) close(listen_sockets[sk]);
2130
2131 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
2132
2133 signal(SIGHUP, SIG_DFL);
2134 signal(SIGCHLD, SIG_DFL);
2135 signal(SIGTERM, SIG_DFL);
2136
2137 /* Re-exec if privilege has been given up, unless deliver_drop_
2138 privilege is set. Reset SIGALRM before exec(). */
2139
2140 if (geteuid() != root_uid && !deliver_drop_privilege)
2141 {
2142 uschar opt[8];
2143 uschar *p = opt;
2144 uschar *extra[7];
2145 int extracount = 1;
2146
2147 signal(SIGALRM, SIG_DFL);
2148 *p++ = '-';
2149 *p++ = 'q';
2150 if ( f.queue_2stage
2151 #ifdef EXPERIMENTAL_QUEUE_RAMP
2152 && !*queuerun_msgid
2153 #endif
2154 ) *p++ = 'q';
2155 if (f.queue_run_first_delivery) *p++ = 'i';
2156 if (f.queue_run_force) *p++ = 'f';
2157 if (f.deliver_force_thaw) *p++ = 'f';
2158 if (f.queue_run_local) *p++ = 'l';
2159 *p = 0;
2160 extra[0] = *queue_name
2161 ? string_sprintf("%sG%s", opt, queue_name) : opt;
2162
2163 #ifdef EXPERIMENTAL_QUEUE_RAMP
2164 if (*queuerun_msgid)
2165 {
2166 extra[extracount++] = queuerun_msgid; /* Trigger only the */
2167 extra[extracount++] = queuerun_msgid; /* one message */
2168 }
2169 #endif
2170
2171 /* If -R or -S were on the original command line, ensure they get
2172 passed on. */
2173
2174 if (deliver_selectstring)
2175 {
2176 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
2177 extra[extracount++] = deliver_selectstring;
2178 }
2179
2180 if (deliver_selectstring_sender)
2181 {
2182 extra[extracount++] = f.deliver_selectstring_sender_regex
2183 ? US"-Sr" : US"-S";
2184 extra[extracount++] = deliver_selectstring_sender;
2185 }
2186
2187 /* Overlay this process with a new execution. */
2188
2189 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
2190 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
2191
2192 /* Control never returns here. */
2193 }
2194
2195 /* No need to re-exec; SIGALRM remains set to the default handler */
2196
2197 #ifdef EXPERIMENTAL_QUEUE_RAMP
2198 if (*queuerun_msgid)
2199 {
2200 f.queue_2stage = FALSE;
2201 queue_run(queuerun_msgid, queuerun_msgid, FALSE);
2202 }
2203 else
2204 #endif
2205 queue_run(NULL, NULL, FALSE);
2206 exim_underbar_exit(EXIT_SUCCESS);
2207 }
2208
2209 if (pid < 0)
2210 {
2211 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
2212 "process failed: %s", strerror(errno));
2213 log_close_all();
2214 }
2215 else
2216 {
2217 for (int i = 0; i < local_queue_run_max; ++i)
2218 if (queue_pid_slots[i] <= 0)
2219 {
2220 queue_pid_slots[i] = pid;
2221 queue_run_count++;
2222 break;
2223 }
2224 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
2225 queue_run_count, queue_run_count == 1 ? "" : "es");
2226 }
2227 }
2228
2229 /* Reset the alarm clock */
2230
2231 sigalrm_seen = FALSE;
2232 #ifdef EXPERIMENTAL_QUEUE_RAMP
2233 if (*queuerun_msgid)
2234 *queuerun_msgid = 0;
2235 else
2236 #endif
2237 ALARM(queue_interval);
2238 }
2239
2240 } /* sigalrm_seen */
2241
2242
2243 /* Sleep till a connection happens if listening, and handle the connection if
2244 that is why we woke up. The FreeBSD operating system requires the use of
2245 select() before accept() because the latter function is not interrupted by
2246 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2247 OS do notice signals in accept() but it does no harm to have the select()
2248 in for all of them - and it won't then be a lurking problem for ports to
2249 new OS. In fact, the later addition of listening on specific interfaces only
2250 requires this way of working anyway. */
2251
2252 if (f.daemon_listen)
2253 {
2254 int lcount, select_errno;
2255 int max_socket = 0;
2256 BOOL select_failed = FALSE;
2257 fd_set select_listen;
2258
2259 FD_ZERO(&select_listen);
2260 if (daemon_notifier_fd >= 0)
2261 FD_SET(daemon_notifier_fd, &select_listen);
2262 for (int sk = 0; sk < listen_socket_count; sk++)
2263 {
2264 FD_SET(listen_sockets[sk], &select_listen);
2265 if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk];
2266 }
2267
2268 DEBUG(D_any) debug_printf("Listening...\n");
2269
2270 /* In rare cases we may have had a SIGCHLD signal in the time between
2271 setting the handler (below) and getting back here. If so, pretend that the
2272 select() was interrupted so that we reap the child. This might still leave
2273 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
2274 only to do the reaping more quickly, it shouldn't result in anything other
2275 than a delay until something else causes a wake-up. */
2276
2277 if (sigchld_seen)
2278 {
2279 lcount = -1;
2280 errno = EINTR;
2281 }
2282 else
2283 lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen,
2284 NULL, NULL, NULL);
2285
2286 if (lcount < 0)
2287 {
2288 select_failed = TRUE;
2289 lcount = 1;
2290 }
2291
2292 /* Clean up any subprocesses that may have terminated. We need to do this
2293 here so that smtp_accept_max_per_host works when a connection to that host
2294 has completed, and we are about to accept a new one. When this code was
2295 later in the sequence, a new connection could be rejected, even though an
2296 old one had just finished. Preserve the errno from any select() failure for
2297 the use of the common select/accept error processing below. */
2298
2299 select_errno = errno;
2300 handle_ending_processes();
2301 errno = select_errno;
2302
2303 #ifndef DISABLE_TLS
2304 /* Create or rotate any required keys */
2305 tls_daemon_init();
2306 #endif
2307
2308 /* Loop for all the sockets that are currently ready to go. If select
2309 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2310 to use the common error code for select/accept below. */
2311
2312 while (lcount-- > 0)
2313 {
2314 int accept_socket = -1;
2315
2316 if (!select_failed)
2317 {
2318 if ( daemon_notifier_fd >= 0
2319 && FD_ISSET(daemon_notifier_fd, &select_listen))
2320 {
2321 FD_CLR(daemon_notifier_fd, &select_listen);
2322 sigalrm_seen = daemon_notification();
2323 break; /* to top of daemon loop */
2324 }
2325 for (int sk = 0; sk < listen_socket_count; sk++)
2326 if (FD_ISSET(listen_sockets[sk], &select_listen))
2327 {
2328 len = sizeof(accepted);
2329 accept_socket = accept(listen_sockets[sk],
2330 (struct sockaddr *)&accepted, &len);
2331 FD_CLR(listen_sockets[sk], &select_listen);
2332 break;
2333 }
2334 }
2335
2336 /* If select or accept has failed and this was not caused by an
2337 interruption, log the incident and try again. With asymmetric TCP/IP
2338 routing errors such as "No route to network" have been seen here. Also
2339 "connection reset by peer" has been seen. These cannot be classed as
2340 disastrous errors, but they could fill up a lot of log. The code in smail
2341 crashes the daemon after 10 successive failures of accept, on the grounds
2342 that some OS fail continuously. Exim originally followed suit, but this
2343 appears to have caused problems. Now it just keeps going, but instead of
2344 logging each error, it batches them up when they are continuous. */
2345
2346 if (accept_socket < 0 && errno != EINTR)
2347 {
2348 if (accept_retry_count == 0)
2349 {
2350 accept_retry_errno = errno;
2351 accept_retry_select_failed = select_failed;
2352 }
2353 else
2354 {
2355 if (errno != accept_retry_errno ||
2356 select_failed != accept_retry_select_failed ||
2357 accept_retry_count >= 50)
2358 {
2359 log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0),
2360 "%d %s() failure%s: %s",
2361 accept_retry_count,
2362 accept_retry_select_failed? "select" : "accept",
2363 (accept_retry_count == 1)? "" : "s",
2364 strerror(accept_retry_errno));
2365 log_close_all();
2366 accept_retry_count = 0;
2367 accept_retry_errno = errno;
2368 accept_retry_select_failed = select_failed;
2369 }
2370 }
2371 accept_retry_count++;
2372 }
2373
2374 else
2375 {
2376 if (accept_retry_count > 0)
2377 {
2378 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2379 accept_retry_count,
2380 accept_retry_select_failed? "select" : "accept",
2381 (accept_retry_count == 1)? "" : "s",
2382 strerror(accept_retry_errno));
2383 log_close_all();
2384 accept_retry_count = 0;
2385 }
2386 }
2387
2388 /* If select/accept succeeded, deal with the connection. */
2389
2390 if (accept_socket >= 0)
2391 {
2392 if (inetd_wait_timeout)
2393 last_connection_time = time(NULL);
2394 handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,
2395 (struct sockaddr *)&accepted);
2396 }
2397 }
2398 }
2399
2400 /* If not listening, then just sleep for the queue interval. If we woke
2401 up early the last time for some other signal, it won't matter because
2402 the alarm signal will wake at the right time. This code originally used
2403 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2404 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2405 select() can be used as an interruptible sleep() on all versions of Unix. */
2406
2407 else
2408 {
2409 struct timeval tv;
2410 tv.tv_sec = queue_interval;
2411 tv.tv_usec = 0;
2412 select(0, NULL, NULL, NULL, &tv);
2413 handle_ending_processes();
2414 }
2415
2416 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2417 for itself, because it isn't doing the waiting itself. */
2418
2419 if (sigchld_seen)
2420 {
2421 sigchld_seen = FALSE;
2422 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
2423 }
2424
2425 /* Handle being woken by SIGHUP. We know at this point that the result
2426 of accept() has been dealt with, so we can re-exec exim safely, first
2427 closing the listening sockets so that they can be reused. Cancel any pending
2428 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2429 that another HUP in quick succession doesn't clobber the new daemon before it
2430 gets going. All log files get closed by the close-on-exec flag; however, if
2431 the exec fails, we need to close the logs. */
2432
2433 if (sighup_seen)
2434 {
2435 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2436 getpid());
2437 for (int sk = 0; sk < listen_socket_count; sk++)
2438 (void)close(listen_sockets[sk]);
2439 ALARM_CLR(0);
2440 signal(SIGHUP, SIG_IGN);
2441 sighup_argv[0] = exim_path;
2442 exim_nullstd();
2443 execv(CS exim_path, (char *const *)sighup_argv);
2444 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2445 getpid(), exim_path, strerror(errno));
2446 log_close_all();
2447 }
2448
2449 } /* End of main loop */
2450
2451 /* Control never reaches here */
2452 }
2453
2454 /* vi: aw ai sw=2
2455 */
2456 /* End of exim_daemon.c */