Log fast-ramp queue-run trigger
[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 *************************************************/
131
132 static void
133 close_daemon_sockets(int daemon_notifier_fd,
134 int * listen_sockets, int listen_socket_count)
135 {
136 if (daemon_notifier_fd >= 0) (void) close(daemon_notifier_fd);
137 for (int i = 0; i < listen_socket_count; i++) (void) close(listen_sockets[i]);
138 }
139
140
141 /*************************************************
142 * Handle a connected SMTP call *
143 *************************************************/
144
145 /* This function is called when an SMTP connection has been accepted.
146 If there are too many, give an error message and close down. Otherwise
147 spin off a sub-process to handle the call. The list of listening sockets
148 is required so that they can be closed in the sub-process. Take care not to
149 leak store in this process - reset the stacking pool at the end.
150
151 Arguments:
152 listen_sockets sockets which are listening for incoming calls
153 listen_socket_count count of listening sockets
154 accept_socket socket of the current accepted call
155 accepted socket information about the current call
156
157 Returns: nothing
158 */
159
160 static void
161 handle_smtp_call(int *listen_sockets, int listen_socket_count,
162 int accept_socket, struct sockaddr *accepted)
163 {
164 pid_t pid;
165 union sockaddr_46 interface_sockaddr;
166 EXIM_SOCKLEN_T ifsize = sizeof(interface_sockaddr);
167 int dup_accept_socket = -1;
168 int max_for_this_host = 0;
169 int save_log_selector = *log_selector;
170 gstring * whofrom;
171
172 rmark reset_point = store_mark();
173
174 /* Make the address available in ASCII representation, and also fish out
175 the remote port. */
176
177 sender_host_address = host_ntoa(-1, accepted, NULL, &sender_host_port);
178 DEBUG(D_any) debug_printf("Connection request from %s port %d\n",
179 sender_host_address, sender_host_port);
180
181 /* Set up the output stream, check the socket has duplicated, and set up the
182 input stream. These operations fail only the exceptional circumstances. Note
183 that never_error() won't use smtp_out if it is NULL. */
184
185 if (!(smtp_out = fdopen(accept_socket, "wb")))
186 {
187 never_error(US"daemon: fdopen() for smtp_out failed", US"", errno);
188 goto ERROR_RETURN;
189 }
190
191 if ((dup_accept_socket = dup(accept_socket)) < 0)
192 {
193 never_error(US"daemon: couldn't dup socket descriptor",
194 US"Connection setup failed", errno);
195 goto ERROR_RETURN;
196 }
197
198 if (!(smtp_in = fdopen(dup_accept_socket, "rb")))
199 {
200 never_error(US"daemon: fdopen() for smtp_in failed",
201 US"Connection setup failed", errno);
202 goto ERROR_RETURN;
203 }
204
205 /* Get the data for the local interface address. Panic for most errors, but
206 "connection reset by peer" just means the connection went away. */
207
208 if (getsockname(accept_socket, (struct sockaddr *)(&interface_sockaddr),
209 &ifsize) < 0)
210 {
211 log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC),
212 "getsockname() failed: %s", strerror(errno));
213 smtp_printf("421 Local problem: getsockname() failed; please try again later\r\n", FALSE);
214 goto ERROR_RETURN;
215 }
216
217 interface_address = host_ntoa(-1, &interface_sockaddr, NULL, &interface_port);
218 DEBUG(D_interface) debug_printf("interface address=%s port=%d\n",
219 interface_address, interface_port);
220
221 /* Build a string identifying the remote host and, if requested, the port and
222 the local interface data. This is for logging; at the end of this function the
223 memory is reclaimed. */
224
225 whofrom = string_append(NULL, 3, "[", sender_host_address, "]");
226
227 if (LOGGING(incoming_port))
228 whofrom = string_fmt_append(whofrom, ":%d", sender_host_port);
229
230 if (LOGGING(incoming_interface))
231 whofrom = string_fmt_append(whofrom, " I=[%s]:%d",
232 interface_address, interface_port);
233
234 (void) string_from_gstring(whofrom); /* Terminate the newly-built string */
235
236 /* Check maximum number of connections. We do not check for reserved
237 connections or unacceptable hosts here. That is done in the subprocess because
238 it might take some time. */
239
240 if (smtp_accept_max > 0 && smtp_accept_count >= smtp_accept_max)
241 {
242 DEBUG(D_any) debug_printf("rejecting SMTP connection: count=%d max=%d\n",
243 smtp_accept_count, smtp_accept_max);
244 smtp_printf("421 Too many concurrent SMTP connections; "
245 "please try again later.\r\n", FALSE);
246 log_write(L_connection_reject,
247 LOG_MAIN, "Connection from %s refused: too many connections",
248 whofrom->s);
249 goto ERROR_RETURN;
250 }
251
252 /* If a load limit above which only reserved hosts are acceptable is defined,
253 get the load average here, and if there are in fact no reserved hosts, do
254 the test right away (saves a fork). If there are hosts, do the check in the
255 subprocess because it might take time. */
256
257 if (smtp_load_reserve >= 0)
258 {
259 load_average = OS_GETLOADAVG();
260 if (smtp_reserve_hosts == NULL && load_average > smtp_load_reserve)
261 {
262 DEBUG(D_any) debug_printf("rejecting SMTP connection: load average = %.2f\n",
263 (double)load_average/1000.0);
264 smtp_printf("421 Too much load; please try again later.\r\n", FALSE);
265 log_write(L_connection_reject,
266 LOG_MAIN, "Connection from %s refused: load average = %.2f",
267 whofrom->s, (double)load_average/1000.0);
268 goto ERROR_RETURN;
269 }
270 }
271
272 /* Check that one specific host (strictly, IP address) is not hogging
273 resources. This is done here to prevent a denial of service attack by someone
274 forcing you to fork lots of times before denying service. The value of
275 smtp_accept_max_per_host is a string which is expanded. This makes it possible
276 to provide host-specific limits according to $sender_host address, but because
277 this is in the daemon mainline, only fast expansions (such as inline address
278 checks) should be used. The documentation is full of warnings. */
279
280 if (smtp_accept_max_per_host != NULL)
281 {
282 uschar *expanded = expand_string(smtp_accept_max_per_host);
283 if (expanded == NULL)
284 {
285 if (!f.expand_string_forcedfail)
286 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
287 "failed for %s: %s", whofrom->s, expand_string_message);
288 }
289 /* For speed, interpret a decimal number inline here */
290 else
291 {
292 uschar *s = expanded;
293 while (isdigit(*s))
294 max_for_this_host = max_for_this_host * 10 + *s++ - '0';
295 if (*s != 0)
296 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
297 "for %s contains non-digit: %s", whofrom->s, expanded);
298 }
299 }
300
301 /* If we have fewer connections than max_for_this_host, we can skip the tedious
302 per host_address checks. Note that at this stage smtp_accept_count contains the
303 count of *other* connections, not including this one. */
304
305 if ((max_for_this_host > 0) &&
306 (smtp_accept_count >= max_for_this_host))
307 {
308 int host_accept_count = 0;
309 int other_host_count = 0; /* keep a count of non matches to optimise */
310
311 for (int i = 0; i < smtp_accept_max; ++i)
312 if (smtp_slots[i].host_address)
313 {
314 if (Ustrcmp(sender_host_address, smtp_slots[i].host_address) == 0)
315 host_accept_count++;
316 else
317 other_host_count++;
318
319 /* Testing all these strings is expensive - see if we can drop out
320 early, either by hitting the target, or finding there are not enough
321 connections left to make the target. */
322
323 if ((host_accept_count >= max_for_this_host) ||
324 ((smtp_accept_count - other_host_count) < max_for_this_host))
325 break;
326 }
327
328 if (host_accept_count >= max_for_this_host)
329 {
330 DEBUG(D_any) debug_printf("rejecting SMTP connection: too many from this "
331 "IP address: count=%d max=%d\n",
332 host_accept_count, max_for_this_host);
333 smtp_printf("421 Too many concurrent SMTP connections "
334 "from this IP address; please try again later.\r\n", FALSE);
335 log_write(L_connection_reject,
336 LOG_MAIN, "Connection from %s refused: too many connections "
337 "from that IP address", whofrom->s);
338 goto ERROR_RETURN;
339 }
340 }
341
342 /* OK, the connection count checks have been passed. Before we can fork the
343 accepting process, we must first log the connection if requested. This logging
344 used to happen in the subprocess, but doing that means that the value of
345 smtp_accept_count can be out of step by the time it is logged. So we have to do
346 the logging here and accept the performance cost. Note that smtp_accept_count
347 hasn't yet been incremented to take account of this connection.
348
349 In order to minimize the cost (because this is going to happen for every
350 connection), do a preliminary selector test here. This saves ploughing through
351 the generalized logging code each time when the selector is false. If the
352 selector is set, check whether the host is on the list for logging. If not,
353 arrange to unset the selector in the subprocess. */
354
355 if (LOGGING(smtp_connection))
356 {
357 uschar *list = hosts_connection_nolog;
358 memset(sender_host_cache, 0, sizeof(sender_host_cache));
359 if (list != NULL && verify_check_host(&list) == OK)
360 save_log_selector &= ~L_smtp_connection;
361 else
362 log_write(L_smtp_connection, LOG_MAIN, "SMTP connection from %s "
363 "(TCP/IP connection count = %d)", whofrom->s, smtp_accept_count + 1);
364 }
365
366 /* Now we can fork the accepting process; do a lookup tidy, just in case any
367 expansion above did a lookup. */
368
369 search_tidyup();
370 pid = exim_fork(US"daemon-accept");
371
372 /* Handle the child process */
373
374 if (pid == 0)
375 {
376 int i;
377 int queue_only_reason = 0;
378 int old_pool = store_pool;
379 int save_debug_selector = debug_selector;
380 BOOL local_queue_only;
381 BOOL session_local_queue_only;
382 #ifdef SA_NOCLDWAIT
383 struct sigaction act;
384 #endif
385
386 smtp_accept_count++; /* So that it includes this process */
387
388 /* May have been modified for the subprocess */
389
390 *log_selector = save_log_selector;
391
392 /* Get the local interface address into permanent store */
393
394 store_pool = POOL_PERM;
395 interface_address = string_copy(interface_address);
396 store_pool = old_pool;
397
398 /* Check for a tls-on-connect port */
399
400 if (host_is_tls_on_connect_port(interface_port)) tls_in.on_connect = TRUE;
401
402 /* Expand smtp_active_hostname if required. We do not do this any earlier,
403 because it may depend on the local interface address (indeed, that is most
404 likely what it depends on.) */
405
406 smtp_active_hostname = primary_hostname;
407 if (raw_active_hostname)
408 {
409 uschar * nah = expand_string(raw_active_hostname);
410 if (!nah)
411 {
412 if (!f.expand_string_forcedfail)
413 {
414 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand \"%s\" "
415 "(smtp_active_hostname): %s", raw_active_hostname,
416 expand_string_message);
417 smtp_printf("421 Local configuration error; "
418 "please try again later.\r\n", FALSE);
419 mac_smtp_fflush();
420 search_tidyup();
421 exim_underbar_exit(EXIT_FAILURE);
422 }
423 }
424 else if (*nah) smtp_active_hostname = nah;
425 }
426
427 /* Initialize the queueing flags */
428
429 queue_check_only();
430 session_local_queue_only = queue_only;
431
432 /* Close the listening sockets, and set the SIGCHLD handler to SIG_IGN.
433 We also attempt to set things up so that children are automatically reaped,
434 but just in case this isn't available, there's a paranoid waitpid() in the
435 loop too (except for systems where we are sure it isn't needed). See the more
436 extensive comment before the reception loop in exim.c for a fuller
437 explanation of this logic. */
438
439 close_daemon_sockets(daemon_notifier_fd, listen_sockets, listen_socket_count);
440
441 /* Set FD_CLOEXEC on the SMTP socket. We don't want any rogue child processes
442 to be able to communicate with them, under any circumstances. */
443 (void)fcntl(accept_socket, F_SETFD,
444 fcntl(accept_socket, F_GETFD) | FD_CLOEXEC);
445 (void)fcntl(dup_accept_socket, F_SETFD,
446 fcntl(dup_accept_socket, F_GETFD) | FD_CLOEXEC);
447
448 #ifdef SA_NOCLDWAIT
449 act.sa_handler = SIG_IGN;
450 sigemptyset(&(act.sa_mask));
451 act.sa_flags = SA_NOCLDWAIT;
452 sigaction(SIGCHLD, &act, NULL);
453 #else
454 signal(SIGCHLD, SIG_IGN);
455 #endif
456 signal(SIGTERM, SIG_DFL);
457
458 /* Attempt to get an id from the sending machine via the RFC 1413
459 protocol. We do this in the sub-process in order not to hold up the
460 main process if there is any delay. Then set up the fullhost information
461 in case there is no HELO/EHLO.
462
463 If debugging is enabled only for the daemon, we must turn if off while
464 finding the id, but turn it on again afterwards so that information about the
465 incoming connection is output. */
466
467 if (f.debug_daemon) debug_selector = 0;
468 verify_get_ident(IDENT_PORT);
469 host_build_sender_fullhost();
470 debug_selector = save_debug_selector;
471
472 DEBUG(D_any)
473 debug_printf("Process %d is handling incoming connection from %s\n",
474 (int)getpid(), sender_fullhost);
475
476 /* Now disable debugging permanently if it's required only for the daemon
477 process. */
478
479 if (f.debug_daemon) debug_selector = 0;
480
481 /* If there are too many child processes for immediate delivery,
482 set the session_local_queue_only flag, which is initialized from the
483 configured value and may therefore already be TRUE. Leave logging
484 till later so it will have a message id attached. Note that there is no
485 possibility of re-calculating this per-message, because the value of
486 smtp_accept_count does not change in this subprocess. */
487
488 if (smtp_accept_queue > 0 && smtp_accept_count > smtp_accept_queue)
489 {
490 session_local_queue_only = TRUE;
491 queue_only_reason = 1;
492 }
493
494 /* Handle the start of the SMTP session, then loop, accepting incoming
495 messages from the SMTP connection. The end will come at the QUIT command,
496 when smtp_setup_msg() returns 0. A break in the connection causes the
497 process to die (see accept.c).
498
499 NOTE: We do *not* call smtp_log_no_mail() if smtp_start_session() fails,
500 because a log line has already been written for all its failure exists
501 (usually "connection refused: <reason>") and writing another one is
502 unnecessary clutter. */
503
504 if (!smtp_start_session())
505 {
506 mac_smtp_fflush();
507 search_tidyup();
508 exim_underbar_exit(EXIT_SUCCESS);
509 }
510
511 for (;;)
512 {
513 int rc;
514 message_id[0] = 0; /* Clear out any previous message_id */
515 reset_point = store_mark(); /* Save current store high water point */
516
517 DEBUG(D_any)
518 debug_printf("Process %d is ready for new message\n", (int)getpid());
519
520 /* Smtp_setup_msg() returns 0 on QUIT or if the call is from an
521 unacceptable host or if an ACL "drop" command was triggered, -1 on
522 connection lost, and +1 on validly reaching DATA. Receive_msg() almost
523 always returns TRUE when smtp_input is true; just retry if no message was
524 accepted (can happen for invalid message parameters). However, it can yield
525 FALSE if the connection was forcibly dropped by the DATA ACL. */
526
527 if ((rc = smtp_setup_msg()) > 0)
528 {
529 BOOL ok = receive_msg(FALSE);
530 search_tidyup(); /* Close cached databases */
531 if (!ok) /* Connection was dropped */
532 {
533 cancel_cutthrough_connection(TRUE, US"receive dropped");
534 mac_smtp_fflush();
535 smtp_log_no_mail(); /* Log no mail if configured */
536 exim_underbar_exit(EXIT_SUCCESS);
537 }
538 if (message_id[0] == 0) continue; /* No message was accepted */
539 }
540 else
541 {
542 if (smtp_out)
543 {
544 int fd = fileno(smtp_in);
545 uschar buf[128];
546
547 mac_smtp_fflush();
548 /* drain socket, for clean TCP FINs */
549 if (fcntl(fd, F_SETFL, O_NONBLOCK) == 0)
550 for(int i = 16; read(fd, buf, sizeof(buf)) > 0 && i > 0; ) i--;
551 }
552 cancel_cutthrough_connection(TRUE, US"message setup dropped");
553 search_tidyup();
554 smtp_log_no_mail(); /* Log no mail if configured */
555
556 /*XXX should we pause briefly, hoping that the client will be the
557 active TCP closer hence get the TCP_WAIT endpoint? */
558 DEBUG(D_receive) debug_printf("SMTP>>(close on process exit)\n");
559 exim_underbar_exit(rc ? EXIT_FAILURE : EXIT_SUCCESS);
560 }
561
562 /* Show the recipients when debugging */
563
564 DEBUG(D_receive)
565 {
566 if (sender_address)
567 debug_printf("Sender: %s\n", sender_address);
568 if (recipients_list)
569 {
570 debug_printf("Recipients:\n");
571 for (int i = 0; i < recipients_count; i++)
572 debug_printf(" %s\n", recipients_list[i].address);
573 }
574 }
575
576 /* A message has been accepted. Clean up any previous delivery processes
577 that have completed and are defunct, on systems where they don't go away
578 by themselves (see comments when setting SIG_IGN above). On such systems
579 (if any) these delivery processes hang around after termination until
580 the next message is received. */
581
582 #ifndef SIG_IGN_WORKS
583 while (waitpid(-1, NULL, WNOHANG) > 0);
584 #endif
585
586 /* Reclaim up the store used in accepting this message */
587
588 {
589 int r = receive_messagecount;
590 BOOL q = f.queue_only_policy;
591 smtp_reset(reset_point);
592 reset_point = NULL;
593 f.queue_only_policy = q;
594 receive_messagecount = r;
595 }
596
597 /* If queue_only is set or if there are too many incoming connections in
598 existence, session_local_queue_only will be TRUE. If it is not, check
599 whether we have received too many messages in this session for immediate
600 delivery. */
601
602 if (!session_local_queue_only &&
603 smtp_accept_queue_per_connection > 0 &&
604 receive_messagecount > smtp_accept_queue_per_connection)
605 {
606 session_local_queue_only = TRUE;
607 queue_only_reason = 2;
608 }
609
610 /* Initialize local_queue_only from session_local_queue_only. If it is not
611 true, and queue_only_load is set, check that the load average is below it.
612 If local_queue_only is set by this means, we also set if for the session if
613 queue_only_load_latch is true (the default). This means that, once set,
614 local_queue_only remains set for any subsequent messages on the same SMTP
615 connection. This is a deliberate choice; even though the load average may
616 fall, it doesn't seem right to deliver later messages on the same call when
617 not delivering earlier ones. However, the are special circumstances such as
618 very long-lived connections from scanning appliances where this is not the
619 best strategy. In such cases, queue_only_load_latch should be set false. */
620
621 if ( !(local_queue_only = session_local_queue_only)
622 && queue_only_load >= 0
623 && (local_queue_only = (load_average = OS_GETLOADAVG()) > queue_only_load)
624 )
625 {
626 queue_only_reason = 3;
627 if (queue_only_load_latch) session_local_queue_only = TRUE;
628 }
629
630 /* Log the queueing here, when it will get a message id attached, but
631 not if queue_only is set (case 0). */
632
633 if (local_queue_only) switch(queue_only_reason)
634 {
635 case 1: log_write(L_delay_delivery,
636 LOG_MAIN, "no immediate delivery: too many connections "
637 "(%d, max %d)", smtp_accept_count, smtp_accept_queue);
638 break;
639
640 case 2: log_write(L_delay_delivery,
641 LOG_MAIN, "no immediate delivery: more than %d messages "
642 "received in one connection", smtp_accept_queue_per_connection);
643 break;
644
645 case 3: log_write(L_delay_delivery,
646 LOG_MAIN, "no immediate delivery: load average %.2f",
647 (double)load_average/1000.0);
648 break;
649 }
650
651 /* If a delivery attempt is required, spin off a new process to handle it.
652 If we are not root, we have to re-exec exim unless deliveries are being
653 done unprivileged. */
654
655 else if ( (!f.queue_only_policy || f.queue_smtp)
656 && !f.deliver_freeze)
657 {
658 pid_t dpid;
659
660 /* Before forking, ensure that the C output buffer is flushed. Otherwise
661 anything that it in it will get duplicated, leading to duplicate copies
662 of the pending output. */
663
664 mac_smtp_fflush();
665
666 if ((dpid = exim_fork(US"daemon-accept-delivery")) == 0)
667 {
668 (void)fclose(smtp_in);
669 (void)fclose(smtp_out);
670
671 /* Don't ever molest the parent's SSL connection, but do clean up
672 the data structures if necessary. */
673
674 #ifndef DISABLE_TLS
675 tls_close(NULL, TLS_NO_SHUTDOWN);
676 #endif
677
678 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
679
680 signal(SIGHUP, SIG_DFL);
681 signal(SIGCHLD, SIG_DFL);
682 signal(SIGTERM, SIG_DFL);
683
684 if (geteuid() != root_uid && !deliver_drop_privilege)
685 {
686 signal(SIGALRM, SIG_DFL);
687 delivery_re_exec(CEE_EXEC_PANIC);
688 /* Control does not return here. */
689 }
690
691 /* No need to re-exec; SIGALRM remains set to the default handler */
692
693 (void) deliver_message(message_id, FALSE, FALSE);
694 search_tidyup();
695 exim_underbar_exit(EXIT_SUCCESS);
696 }
697
698 if (dpid > 0)
699 {
700 release_cutthrough_connection(US"passed for delivery");
701 DEBUG(D_any) debug_printf("forked delivery process %d\n", (int)dpid);
702 }
703 else
704 {
705 cancel_cutthrough_connection(TRUE, US"delivery fork failed");
706 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: delivery process fork "
707 "failed: %s", strerror(errno));
708 }
709 }
710 }
711 }
712
713
714 /* Carrying on in the parent daemon process... Can't do much if the fork
715 failed. Otherwise, keep count of the number of accepting processes and
716 remember the pid for ticking off when the child completes. */
717
718 if (pid < 0)
719 never_error(US"daemon: accept process fork failed", US"Fork failed", errno);
720 else
721 {
722 for (int i = 0; i < smtp_accept_max; ++i)
723 if (smtp_slots[i].pid <= 0)
724 {
725 smtp_slots[i].pid = pid;
726 /* Connection closes come asyncronously, so we cannot stack this store */
727 if (smtp_accept_max_per_host)
728 smtp_slots[i].host_address = string_copy_malloc(sender_host_address);
729 smtp_accept_count++;
730 break;
731 }
732 DEBUG(D_any) debug_printf("%d SMTP accept process%s running\n",
733 smtp_accept_count, smtp_accept_count == 1 ? "" : "es");
734 }
735
736 /* Get here via goto in error cases */
737
738 ERROR_RETURN:
739
740 /* Close the streams associated with the socket which will also close the
741 socket fds in this process. We can't do anything if fclose() fails, but
742 logging brings it to someone's attention. However, "connection reset by peer"
743 isn't really a problem, so skip that one. On Solaris, a dropped connection can
744 manifest itself as a broken pipe, so drop that one too. If the streams don't
745 exist, something went wrong while setting things up. Make sure the socket
746 descriptors are closed, in order to drop the connection. */
747
748 if (smtp_out)
749 {
750 if (fclose(smtp_out) != 0 && errno != ECONNRESET && errno != EPIPE)
751 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_out) failed: %s",
752 strerror(errno));
753 smtp_out = NULL;
754 }
755 else (void)close(accept_socket);
756
757 if (smtp_in)
758 {
759 if (fclose(smtp_in) != 0 && errno != ECONNRESET && errno != EPIPE)
760 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_in) failed: %s",
761 strerror(errno));
762 smtp_in = NULL;
763 }
764 else (void)close(dup_accept_socket);
765
766 /* Release any store used in this process, including the store used for holding
767 the incoming host address and an expanded active_hostname. */
768
769 log_close_all();
770 interface_address =
771 sender_host_address = NULL;
772 store_reset(reset_point);
773 sender_host_address = NULL;
774 }
775
776
777
778
779 /*************************************************
780 * Check wildcard listen special cases *
781 *************************************************/
782
783 /* This function is used when binding and listening on lists of addresses and
784 ports. It tests for special cases of wildcard listening, when IPv4 and IPv6
785 sockets may interact in different ways in different operating systems. It is
786 passed an error number, the list of listening addresses, and the current
787 address. Two checks are available: for a previous wildcard IPv6 address, or for
788 a following wildcard IPv4 address, in both cases on the same port.
789
790 In practice, pairs of wildcard addresses should be adjacent in the address list
791 because they are sorted that way below.
792
793 Arguments:
794 eno the error number
795 addresses the list of addresses
796 ipa the current IP address
797 back if TRUE, check for previous wildcard IPv6 address
798 if FALSE, check for a following wildcard IPv4 address
799
800 Returns: TRUE or FALSE
801 */
802
803 static BOOL
804 check_special_case(int eno, ip_address_item *addresses, ip_address_item *ipa,
805 BOOL back)
806 {
807 ip_address_item *ipa2;
808
809 /* For the "back" case, if the failure was "address in use" for a wildcard IPv4
810 address, seek a previous IPv6 wildcard address on the same port. As it is
811 previous, it must have been successfully bound and be listening. Flag it as a
812 "6 including 4" listener. */
813
814 if (back)
815 {
816 if (eno != EADDRINUSE || ipa->address[0] != 0) return FALSE;
817 for (ipa2 = addresses; ipa2 != ipa; ipa2 = ipa2->next)
818 {
819 if (ipa2->address[1] == 0 && ipa2->port == ipa->port)
820 {
821 ipa2->v6_include_v4 = TRUE;
822 return TRUE;
823 }
824 }
825 }
826
827 /* For the "forward" case, if the current address is a wildcard IPv6 address,
828 we seek a following wildcard IPv4 address on the same port. */
829
830 else
831 {
832 if (ipa->address[0] != ':' || ipa->address[1] != 0) return FALSE;
833 for (ipa2 = ipa->next; ipa2 != NULL; ipa2 = ipa2->next)
834 if (ipa2->address[0] == 0 && ipa->port == ipa2->port) return TRUE;
835 }
836
837 return FALSE;
838 }
839
840
841
842
843 /*************************************************
844 * Handle terminating subprocesses *
845 *************************************************/
846
847 /* Handle the termination of child processes. Theoretically, this need be done
848 only when sigchld_seen is TRUE, but rumour has it that some systems lose
849 SIGCHLD signals at busy times, so to be on the safe side, this function is
850 called each time round. It shouldn't be too expensive.
851
852 Arguments: none
853 Returns: nothing
854 */
855
856 static void
857 handle_ending_processes(void)
858 {
859 int status;
860 pid_t pid;
861
862 while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
863 {
864 DEBUG(D_any)
865 {
866 debug_printf("child %d ended: status=0x%x\n", (int)pid, status);
867 #ifdef WCOREDUMP
868 if (WIFEXITED(status))
869 debug_printf(" normal exit, %d\n", WEXITSTATUS(status));
870 else if (WIFSIGNALED(status))
871 debug_printf(" signal exit, signal %d%s\n", WTERMSIG(status),
872 WCOREDUMP(status) ? " (core dumped)" : "");
873 #endif
874 }
875
876 /* If it's a listening daemon for which we are keeping track of individual
877 subprocesses, deal with an accepting process that has terminated. */
878
879 if (smtp_slots)
880 {
881 int i;
882 for (i = 0; i < smtp_accept_max; i++)
883 if (smtp_slots[i].pid == pid)
884 {
885 if (smtp_slots[i].host_address)
886 store_free(smtp_slots[i].host_address);
887 smtp_slots[i] = empty_smtp_slot;
888 if (--smtp_accept_count < 0) smtp_accept_count = 0;
889 DEBUG(D_any) debug_printf("%d SMTP accept process%s now running\n",
890 smtp_accept_count, (smtp_accept_count == 1)? "" : "es");
891 break;
892 }
893 if (i < smtp_accept_max) continue; /* Found an accepting process */
894 }
895
896 /* If it wasn't an accepting process, see if it was a queue-runner
897 process that we are tracking. */
898
899 if (queue_pid_slots)
900 {
901 int max = atoi(CS expand_string(queue_run_max));
902 for (int i = 0; i < max; i++)
903 if (queue_pid_slots[i] == pid)
904 {
905 queue_pid_slots[i] = 0;
906 if (--queue_run_count < 0) queue_run_count = 0;
907 DEBUG(D_any) debug_printf("%d queue-runner process%s now running\n",
908 queue_run_count, (queue_run_count == 1)? "" : "es");
909 break;
910 }
911 }
912 }
913 }
914
915
916
917 static void
918 set_pid_file_path(void)
919 {
920 if (override_pid_file_path)
921 pid_file_path = override_pid_file_path;
922
923 if (!*pid_file_path)
924 pid_file_path = string_sprintf("%s/exim-daemon.pid", spool_directory);
925 }
926
927
928 /* Remove the daemon's pidfile. Note: runs with root privilege,
929 as a direct child of the daemon. Does not return. */
930
931 void
932 delete_pid_file(void)
933 {
934 uschar * daemon_pid = string_sprintf("%d\n", (int)getppid());
935 FILE * f;
936
937 set_pid_file_path();
938 if ((f = Ufopen(pid_file_path, "rb")))
939 {
940 if ( fgets(CS big_buffer, big_buffer_size, f)
941 && Ustrcmp(daemon_pid, big_buffer) == 0
942 )
943 if (Uunlink(pid_file_path) == 0)
944 {
945 DEBUG(D_any)
946 debug_printf("%s unlink: %s\n", pid_file_path, strerror(errno));
947 }
948 else
949 DEBUG(D_any)
950 debug_printf("unlinked %s\n", pid_file_path);
951 fclose(f);
952 }
953 else
954 DEBUG(D_any)
955 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
956 pid_file_path));
957 exim_exit(EXIT_SUCCESS);
958 }
959
960
961 /* Called by the daemon; exec a child to get the pid file deleted
962 since we may require privs for the containing directory */
963
964 static void
965 daemon_die(void)
966 {
967 int pid;
968
969 if (daemon_notifier_fd >= 0)
970 {
971 close(daemon_notifier_fd);
972 daemon_notifier_fd = -1;
973 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
974 {
975 uschar * s = expand_string(notifier_socket);
976 DEBUG(D_any) debug_printf("unlinking notifier socket %s\n", s);
977 Uunlink(s);
978 }
979 #endif
980 }
981
982 if (f.running_in_test_harness || write_pid)
983 {
984 if ((pid = exim_fork(US"daemon-del-pidfile")) == 0)
985 {
986 if (override_pid_file_path)
987 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 3,
988 "-oP", override_pid_file_path, "-oPX");
989 else
990 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 1, "-oPX");
991
992 /* Control never returns here. */
993 }
994 if (pid > 0)
995 child_close(pid, 1);
996 }
997 exim_exit(EXIT_SUCCESS);
998 }
999
1000
1001 /*************************************************
1002 * Listener socket for local work prompts *
1003 *************************************************/
1004
1005 static void
1006 daemon_notifier_socket(void)
1007 {
1008 int fd;
1009 const uschar * where;
1010 struct sockaddr_un sa_un = {.sun_family = AF_UNIX};
1011 int len;
1012
1013 if (override_local_interfaces && !override_pid_file_path)
1014 {
1015 DEBUG(D_any)
1016 debug_printf("-oX used without -oP so not creating notifier socket\n");
1017 return;
1018 }
1019
1020 DEBUG(D_any) debug_printf("creating notifier socket\n");
1021
1022 #ifdef SOCK_CLOEXEC
1023 if ((fd = socket(PF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0)
1024 { where = US"socket"; goto bad; }
1025 #else
1026 if ((fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0)
1027 { where = US"socket"; goto bad; }
1028 (void)fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
1029 #endif
1030
1031 #ifdef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1032 sa_un.sun_path[0] = 0; /* Abstract local socket addr - Linux-specific? */
1033 len = offsetof(struct sockaddr_un, sun_path) + 1
1034 + snprintf(sa_un.sun_path+1, sizeof(sa_un.sun_path)-1, "%s",
1035 expand_string(notifier_socket));
1036 DEBUG(D_any) debug_printf(" @%s\n", sa_un.sun_path+1);
1037 #else /* filesystem-visible and persistent; will neeed removal */
1038 len = offsetof(struct sockaddr_un, sun_path)
1039 + snprintf(sa_un.sun_path, sizeof(sa_un.sun_path), "%s",
1040 expand_string(notifier_socket));
1041 DEBUG(D_any) debug_printf(" %s\n", sa_un.sun_path);
1042 #endif
1043
1044 if (bind(fd, (const struct sockaddr *)&sa_un, len) < 0)
1045 { where = US"bind"; goto bad; }
1046
1047 #ifdef SO_PASSCRED /* Linux */
1048 if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0)
1049 { where = US"SO_PASSCRED"; goto bad2; }
1050 #elif defined(LOCAL_CREDS) /* FreeBSD-ish */
1051 if (setsockopt(fd, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
1052 { where = US"LOCAL_CREDS"; goto bad2; }
1053 #endif
1054
1055 /* debug_printf("%s: fd %d\n", __FUNCTION__, fd); */
1056 daemon_notifier_fd = fd;
1057 return;
1058
1059 bad2:
1060 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1061 Uunlink(sa_un.sun_path);
1062 #endif
1063 bad:
1064 log_write(0, LOG_MAIN|LOG_PANIC, "%s %s: %s",
1065 __FUNCTION__, where, strerror(errno));
1066 close(fd);
1067 return;
1068 }
1069
1070
1071 static uschar queuerun_msgid[MESSAGE_ID_LENGTH+1];
1072
1073 /* Return TRUE if a sigalrm should be emulated */
1074 static BOOL
1075 daemon_notification(void)
1076 {
1077 uschar buf[256], cbuf[256];
1078 struct sockaddr_un sa_un;
1079 struct iovec iov = {.iov_base = buf, .iov_len = sizeof(buf)-1};
1080 struct msghdr msg = { .msg_name = &sa_un,
1081 .msg_namelen = sizeof(sa_un),
1082 .msg_iov = &iov,
1083 .msg_iovlen = 1,
1084 .msg_control = cbuf,
1085 .msg_controllen = sizeof(cbuf)
1086 };
1087 ssize_t sz;
1088 struct cmsghdr * cp;
1089
1090 buf[sizeof(buf)-1] = 0;
1091 if ((sz = recvmsg(daemon_notifier_fd, &msg, 0)) <= 0) return FALSE;
1092 if (sz >= sizeof(buf)) return FALSE;
1093
1094 #ifdef notdef
1095 debug_printf("addrlen %d\n", msg.msg_namelen);
1096 #endif
1097 DEBUG(D_queue_run) debug_printf("%s from addr '%s%.*s'\n", __FUNCTION__,
1098 *sa_un.sun_path ? "" : "@",
1099 (int)msg.msg_namelen - (*sa_un.sun_path ? 0 : 1),
1100 sa_un.sun_path + (*sa_un.sun_path ? 0 : 1));
1101
1102 /* Refuse to handle the item unless the peer has good credentials */
1103 #ifdef SCM_CREDENTIALS
1104 # define EXIM_SCM_CR_TYPE SCM_CREDENTIALS
1105 #elif defined(LOCAL_CREDS) && defined(SCM_CREDS)
1106 # define EXIM_SCM_CR_TYPE SCM_CREDS
1107 #else
1108 /* The OS has no way to get the creds of the caller (for a unix/datagram socket.
1109 Punt; don't try to check. */
1110 #endif
1111
1112 #ifdef EXIM_SCM_CR_TYPE
1113 for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg);
1114 cp;
1115 cp = CMSG_NXTHDR(&msg, cp))
1116 if (cp->cmsg_level == SOL_SOCKET && cp->cmsg_type == EXIM_SCM_CR_TYPE)
1117 {
1118 # ifdef SCM_CREDENTIALS /* Linux */
1119 struct ucred * cr = (struct ucred *) CMSG_DATA(cp);
1120 if (cr->uid && cr->uid != exim_uid)
1121 {
1122 DEBUG(D_queue_run) debug_printf("%s: sender creds pid %d uid %d gid %d\n",
1123 __FUNCTION__, (int)cr->pid, (int)cr->uid, (int)cr->gid);
1124 return FALSE;
1125 }
1126 # elif defined(LOCAL_CREDS) /* BSD-ish */
1127 struct sockcred * cr = (struct sockcred *) CMSG_DATA(cp);
1128 if (cr->sc_uid && cr->sc_uid != exim_uid)
1129 {
1130 DEBUG(D_queue_run) debug_printf("%s: sender creds pid ??? uid %d gid %d\n",
1131 __FUNCTION__, (int)cr->sc_uid, (int)cr->sc_gid);
1132 return FALSE;
1133 }
1134 # endif
1135 break;
1136 }
1137 #endif
1138
1139 buf[sz] = 0;
1140 switch (buf[0])
1141 {
1142 #ifdef EXPERIMENTAL_QUEUE_RAMP
1143 case NOTIFY_MSG_QRUN:
1144 /* this should be a message_id */
1145 DEBUG(D_queue_run)
1146 debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1);
1147 memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1);
1148 return TRUE;
1149 #endif /*EXPERIMENTAL_QUEUE_RAMP*/
1150
1151 case NOTIFY_QUEUE_SIZE_REQ:
1152 {
1153 uschar buf[16];
1154 int len = snprintf(CS buf, sizeof(buf), "%u", queue_count_cached());
1155
1156 DEBUG(D_queue_run)
1157 debug_printf("%s: queue size request: %s\n", __FUNCTION__, buf);
1158
1159 if (sendto(daemon_notifier_fd, buf, len, 0,
1160 (const struct sockaddr *)&sa_un, msg.msg_namelen) < 0)
1161 log_write(0, LOG_MAIN|LOG_PANIC,
1162 "%s: sendto: %s\n", __FUNCTION__, strerror(errno));
1163 return FALSE;
1164 }
1165 }
1166 return FALSE;
1167 }
1168
1169
1170 /*************************************************
1171 * Exim Daemon Mainline *
1172 *************************************************/
1173
1174 /* The daemon can do two jobs, either of which is optional:
1175
1176 (1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1177 each one. This is requested by the -bd option, with -oX specifying the SMTP
1178 port on which to listen (for testing).
1179
1180 (2) Spawns a queue-running process every so often. This is controlled by the
1181 -q option with a an interval time. (If no time is given, a single queue run
1182 is done from the main function, and control doesn't get here.)
1183
1184 Root privilege is required in order to attach to port 25. Some systems require
1185 it when calling socket() rather than bind(). To cope with all cases, we run as
1186 root for both socket() and bind(). Some systems also require root in order to
1187 write to the pid file directory. This function must therefore be called as root
1188 if it is to work properly in all circumstances. Once the socket is bound and
1189 the pid file written, root privilege is given up if there is an exim uid.
1190
1191 There are no arguments to this function, and it never returns. */
1192
1193 void
1194 daemon_go(void)
1195 {
1196 struct passwd *pw;
1197 int *listen_sockets = NULL;
1198 int listen_socket_count = 0;
1199 ip_address_item *addresses = NULL;
1200 time_t last_connection_time = (time_t)0;
1201 int local_queue_run_max = atoi(CS expand_string(queue_run_max));
1202
1203 process_purpose = US"daemon";
1204
1205 /* If any debugging options are set, turn on the D_pid bit so that all
1206 debugging lines get the pid added. */
1207
1208 DEBUG(D_any|D_v) debug_selector |= D_pid;
1209
1210 if (f.inetd_wait_mode)
1211 {
1212 listen_socket_count = 1;
1213 listen_sockets = store_get(sizeof(int), FALSE);
1214 (void) close(3);
1215 if (dup2(0, 3) == -1)
1216 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1217 "failed to dup inetd socket safely away: %s", strerror(errno));
1218
1219 listen_sockets[0] = 3;
1220 (void) close(0);
1221 (void) close(1);
1222 (void) close(2);
1223 exim_nullstd();
1224
1225 if (debug_file == stderr)
1226 {
1227 /* need a call to log_write before call to open debug_file, so that
1228 log.c:file_path has been initialised. This is unfortunate. */
1229 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1230
1231 fclose(debug_file);
1232 debug_file = NULL;
1233 exim_nullstd(); /* re-open fd2 after we just closed it again */
1234 debug_logging_activate(US"-wait", NULL);
1235 }
1236
1237 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1238
1239 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1240 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1241
1242 if (tcp_nodelay)
1243 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1244 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1245 strerror(errno));
1246 }
1247
1248
1249 if (f.inetd_wait_mode || f.daemon_listen)
1250 {
1251 /* If any option requiring a load average to be available during the
1252 reception of a message is set, call os_getloadavg() while we are root
1253 for those OS for which this is necessary the first time it is called (in
1254 order to perform an "open" on the kernel memory file). */
1255
1256 #ifdef LOAD_AVG_NEEDS_ROOT
1257 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1258 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1259 (void)os_getloadavg();
1260 #endif
1261 }
1262
1263
1264 /* Do the preparation for setting up a listener on one or more interfaces, and
1265 possible on various ports. This is controlled by the combination of
1266 local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1267 (which is a list of default ports to use for those items in local_interfaces
1268 that do not specify a port). The -oX command line option can be used to
1269 override one or both of these options.
1270
1271 If local_interfaces is not set, the default is to listen on all interfaces.
1272 When it is set, it can include "all IPvx interfaces" as an item. This is useful
1273 when different ports are in use.
1274
1275 It turns out that listening on all interfaces is messy in an IPv6 world,
1276 because several different implementation approaches have been taken. This code
1277 is now supposed to work with all of them. The point of difference is whether an
1278 IPv6 socket that is listening on all interfaces will receive incoming IPv4
1279 calls or not. We also have to cope with the case when IPv6 libraries exist, but
1280 there is no IPv6 support in the kernel.
1281
1282 . On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1283 addresses. However, if an IPv4 socket is also listening on all interfaces,
1284 calls are directed to the appropriate socket.
1285
1286 . On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1287 give them as mapped addresses, but an attempt also to listen on an IPv4
1288 socket on all interfaces causes an error.
1289
1290 . On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1291 two sockets if you want to accept both kinds of call.
1292
1293 . FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1294 can be turned off, to make it behave like the versions of Linux described
1295 above.
1296
1297 . I heard a report that the USAGI IPv6 stack for Linux has implemented
1298 IPV6_V6ONLY.
1299
1300 So, what we do when IPv6 is supported is as follows:
1301
1302 (1) After it is set up, the list of interfaces is scanned for wildcard
1303 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1304 port, the list is re-arranged so that they are together, with the IPv6
1305 wildcard first.
1306
1307 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1308 carry on if an IPv4 wildcard socket for the same port follows later in the
1309 list. This allows Exim to carry on in the case when the kernel has no IPv6
1310 support.
1311
1312 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1313 option is defined. However, if setting fails, carry on regardless (but log
1314 the incident).
1315
1316 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1317 error.
1318
1319 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1320 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1321 port (which must have succeeded or we wouldn't have got this far), we
1322 assume we are in the situation where just a single socket is permitted,
1323 and ignore the error.
1324
1325 Phew!
1326
1327 The preparation code decodes options and sets up the relevant data. We do this
1328 first, so that we can return non-zero if there are any syntax errors, and also
1329 write to stderr. */
1330
1331 if (f.daemon_listen && !f.inetd_wait_mode)
1332 {
1333 int *default_smtp_port;
1334 int sep;
1335 int pct = 0;
1336 uschar *s;
1337 const uschar * list;
1338 uschar *local_iface_source = US"local_interfaces";
1339 ip_address_item *ipa;
1340 ip_address_item **pipa;
1341
1342 /* If -oX was used, disable the writing of a pid file unless -oP was
1343 explicitly used to force it. Then scan the string given to -oX. Any items
1344 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1345 Any other items are used to override local_interfaces. */
1346
1347 if (override_local_interfaces)
1348 {
1349 gstring * new_smtp_port = NULL;
1350 gstring * new_local_interfaces = NULL;
1351
1352 if (!override_pid_file_path) write_pid = FALSE;
1353
1354 list = override_local_interfaces;
1355 sep = 0;
1356 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1357 {
1358 uschar joinstr[4];
1359 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
1360
1361 if (!*gp)
1362 {
1363 joinstr[0] = sep;
1364 joinstr[1] = ' ';
1365 *gp = string_catn(*gp, US"<", 1);
1366 }
1367
1368 *gp = string_catn(*gp, joinstr, 2);
1369 *gp = string_cat (*gp, s);
1370 }
1371
1372 if (new_smtp_port)
1373 {
1374 daemon_smtp_port = string_from_gstring(new_smtp_port);
1375 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1376 daemon_smtp_port);
1377 }
1378
1379 if (new_local_interfaces)
1380 {
1381 local_interfaces = string_from_gstring(new_local_interfaces);
1382 local_iface_source = US"-oX data";
1383 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1384 local_interfaces);
1385 }
1386 }
1387
1388 /* Create a list of default SMTP ports, to be used if local_interfaces
1389 contains entries without explicit ports. First count the number of ports, then
1390 build a translated list in a vector. */
1391
1392 list = daemon_smtp_port;
1393 sep = 0;
1394 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1395 pct++;
1396 default_smtp_port = store_get((pct+1) * sizeof(int), FALSE);
1397 list = daemon_smtp_port;
1398 sep = 0;
1399 for (pct = 0;
1400 (s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size));
1401 pct++)
1402 {
1403 if (isdigit(*s))
1404 {
1405 uschar *end;
1406 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1407 if (end != s + Ustrlen(s))
1408 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1409 }
1410 else
1411 {
1412 struct servent *smtp_service = getservbyname(CS s, "tcp");
1413 if (!smtp_service)
1414 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1415 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1416 }
1417 }
1418 default_smtp_port[pct] = 0;
1419
1420 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1421
1422 list = tls_in.on_connect_ports;
1423 sep = 0;
1424 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1425 if (!isdigit(*s))
1426 {
1427 gstring * g = NULL;
1428
1429 list = tls_in.on_connect_ports;
1430 tls_in.on_connect_ports = NULL;
1431 sep = 0;
1432 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1433 {
1434 if (!isdigit(*s))
1435 {
1436 struct servent * smtp_service = getservbyname(CS s, "tcp");
1437 if (!smtp_service)
1438 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1439 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
1440 }
1441 g = string_append_listele(g, ':', s);
1442 }
1443 if (g)
1444 tls_in.on_connect_ports = g->s;
1445 break;
1446 }
1447
1448 /* Create the list of local interfaces, possibly with ports included. This
1449 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1450 values are converted below. */
1451
1452 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1453
1454 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1455 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1456 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1457 anyway, but we need to know which are the wildcard addresses, and the shorter
1458 strings are neater.
1459
1460 In the same scan, fill in missing port numbers from the default list. When
1461 there is more than one item in the list, extra items are created. */
1462
1463 for (ipa = addresses; ipa; ipa = ipa->next)
1464 {
1465 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1466 ipa->address[0] = 0;
1467 else if (Ustrcmp(ipa->address, "::0") == 0)
1468 {
1469 ipa->address[0] = ':';
1470 ipa->address[1] = 0;
1471 }
1472
1473 if (ipa->port > 0) continue;
1474
1475 if (daemon_smtp_port[0] <= 0)
1476 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1477 "%s and daemon_smtp_port is unset; cannot start daemon",
1478 ipa->address[0] == 0 ? US"\"all IPv4\"" :
1479 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
1480
1481 ipa->port = default_smtp_port[0];
1482 for (int i = 1; default_smtp_port[i] > 0; i++)
1483 {
1484 ip_address_item *new = store_get(sizeof(ip_address_item), FALSE);
1485
1486 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1487 new->port = default_smtp_port[i];
1488 new->next = ipa->next;
1489 ipa->next = new;
1490 ipa = new;
1491 }
1492 }
1493
1494 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1495 wildcard for the same port, ensure that (a) they are together and (b) the
1496 IPv6 address comes first. This makes handling the messy features easier, and
1497 also simplifies the construction of the "daemon started" log line. */
1498
1499 pipa = &addresses;
1500 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
1501 {
1502 ip_address_item *ipa2;
1503
1504 /* Handle an IPv4 wildcard */
1505
1506 if (ipa->address[0] == 0)
1507 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1508 {
1509 ip_address_item *ipa3 = ipa2->next;
1510 if (ipa3->address[0] == ':' &&
1511 ipa3->address[1] == 0 &&
1512 ipa3->port == ipa->port)
1513 {
1514 ipa2->next = ipa3->next;
1515 ipa3->next = ipa;
1516 *pipa = ipa3;
1517 break;
1518 }
1519 }
1520
1521 /* Handle an IPv6 wildcard. */
1522
1523 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
1524 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1525 {
1526 ip_address_item *ipa3 = ipa2->next;
1527 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1528 {
1529 ipa2->next = ipa3->next;
1530 ipa3->next = ipa->next;
1531 ipa->next = ipa3;
1532 ipa = ipa3;
1533 break;
1534 }
1535 }
1536 }
1537
1538 /* Get a vector to remember all the sockets in */
1539
1540 for (ipa = addresses; ipa; ipa = ipa->next)
1541 listen_socket_count++;
1542 listen_sockets = store_get(sizeof(int) * listen_socket_count, FALSE);
1543
1544 } /* daemon_listen but not inetd_wait_mode */
1545
1546 if (f.daemon_listen)
1547 {
1548
1549 /* Do a sanity check on the max connects value just to save us from getting
1550 a huge amount of store. */
1551
1552 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1553
1554 /* There's no point setting smtp_accept_queue unless it is less than the max
1555 connects limit. The configuration reader ensures that the max is set if the
1556 queue-only option is set. */
1557
1558 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1559
1560 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1561 track of them for total number and queue/host limits. */
1562
1563 if (smtp_accept_max > 0)
1564 {
1565 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), FALSE);
1566 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
1567 }
1568 }
1569
1570 /* The variable background_daemon is always false when debugging, but
1571 can also be forced false in order to keep a non-debugging daemon in the
1572 foreground. If background_daemon is true, close all open file descriptors that
1573 we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1574 do this for inetd_wait mode.
1575
1576 This is protection against any called functions (in libraries, or in
1577 Perl, or whatever) that think they can write to stderr (or stdout). Before this
1578 was added, it was quite likely that an SMTP connection would use one of these
1579 file descriptors, in which case writing random stuff to it caused chaos.
1580
1581 Then disconnect from the controlling terminal, Most modern Unixes seem to have
1582 setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1583 setsid() can be #defined as a no-op, or as something else. */
1584
1585 if (f.background_daemon || f.inetd_wait_mode)
1586 {
1587 log_close_all(); /* Just in case anything was logged earlier */
1588 search_tidyup(); /* Just in case any were used in reading the config. */
1589 (void)close(0); /* Get rid of stdin/stdout/stderr */
1590 (void)close(1);
1591 (void)close(2);
1592 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
1593 log_stderr = NULL; /* So no attempt to copy paniclog output */
1594 }
1595
1596 if (f.background_daemon)
1597 {
1598 /* If the parent process of this one has pid == 1, we are re-initializing the
1599 daemon as the result of a SIGHUP. In this case, there is no need to do
1600 anything, because the controlling terminal has long gone. Otherwise, fork, in
1601 case current process is a process group leader (see 'man setsid' for an
1602 explanation) before calling setsid(). */
1603
1604 if (getppid() != 1)
1605 {
1606 pid_t pid = exim_fork(US"daemon");
1607 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1608 "fork() failed when starting daemon: %s", strerror(errno));
1609 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1610 (void)setsid(); /* release controlling terminal */
1611 }
1612 }
1613
1614 /* We are now in the disconnected, daemon process (unless debugging). Set up
1615 the listening sockets if required. */
1616
1617 daemon_notifier_socket();
1618
1619 if (f.daemon_listen && !f.inetd_wait_mode)
1620 {
1621 int sk;
1622 ip_address_item *ipa;
1623
1624 /* For each IP address, create a socket, bind it to the appropriate port, and
1625 start listening. See comments above about IPv6 sockets that may or may not
1626 accept IPv4 calls when listening on all interfaces. We also have to cope with
1627 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1628 listening, provided a wildcard IPv4 socket for the same port follows. */
1629
1630 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1631 {
1632 BOOL wildcard;
1633 ip_address_item *ipa2;
1634 int af;
1635
1636 if (Ustrchr(ipa->address, ':') != NULL)
1637 {
1638 af = AF_INET6;
1639 wildcard = ipa->address[1] == 0;
1640 }
1641 else
1642 {
1643 af = AF_INET;
1644 wildcard = ipa->address[0] == 0;
1645 }
1646
1647 if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0)
1648 {
1649 if (check_special_case(0, addresses, ipa, FALSE))
1650 {
1651 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1652 "listening (%s): will use IPv4", strerror(errno));
1653 goto SKIP_SOCKET;
1654 }
1655 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1656 (af == AF_INET6)? '6' : '4', strerror(errno));
1657 }
1658
1659 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1660 available. Just log failure (can get protocol not available, just like
1661 socket creation can). */
1662
1663 #ifdef IPV6_V6ONLY
1664 if (af == AF_INET6 && wildcard &&
1665 setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, CS (&on),
1666 sizeof(on)) < 0)
1667 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1668 "socket failed (%s): carrying on without it", strerror(errno));
1669 #endif /* IPV6_V6ONLY */
1670
1671 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1672 is being handled. Without this, a connection will prevent reuse of the
1673 smtp port for listening. */
1674
1675 if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR,
1676 US (&on), sizeof(on)) < 0)
1677 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1678 "failed when starting daemon: %s", strerror(errno));
1679
1680 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1681 disable this because it breaks some broken clients. */
1682
1683 if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY,
1684 US (&on), sizeof(on));
1685
1686 /* Now bind the socket to the required port; if Exim is being restarted
1687 it may not always be possible to bind immediately, even with SO_REUSEADDR
1688 set, so try 10 times, waiting between each try. After 10 failures, we give
1689 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1690 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1691 address for the same port, ignore the error on the grounds that we must be
1692 in a system where the IPv6 socket accepts both kinds of call. This is
1693 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1694 listen() stage instead. */
1695
1696 #ifdef TCP_FASTOPEN
1697 f.tcp_fastopen_ok = TRUE;
1698 #endif
1699 for(;;)
1700 {
1701 uschar *msg, *addr;
1702 if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break;
1703 if (check_special_case(errno, addresses, ipa, TRUE))
1704 {
1705 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1706 "listen() success; EADDRINUSE ignored\n");
1707 (void)close(listen_sockets[sk]);
1708 goto SKIP_SOCKET;
1709 }
1710 msg = US strerror(errno);
1711 addr = wildcard
1712 ? af == AF_INET6
1713 ? US"(any IPv6)"
1714 : US"(any IPv4)"
1715 : ipa->address;
1716 if (daemon_startup_retries <= 0)
1717 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1718 "socket bind() to port %d for address %s failed: %s: "
1719 "daemon abandoned", ipa->port, addr, msg);
1720 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
1721 "failed: %s: waiting %s before trying again (%d more %s)",
1722 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1723 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1724 daemon_startup_retries--;
1725 sleep(daemon_startup_sleep);
1726 }
1727
1728 DEBUG(D_any)
1729 if (wildcard)
1730 debug_printf("listening on all interfaces (IPv%c) port %d\n",
1731 af == AF_INET6 ? '6' : '4', ipa->port);
1732 else
1733 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
1734
1735 #if defined(TCP_FASTOPEN) && !defined(__APPLE__)
1736 if ( f.tcp_fastopen_ok
1737 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1738 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
1739 {
1740 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1741 f.tcp_fastopen_ok = FALSE;
1742 }
1743 #endif
1744
1745 /* Start listening on the bound socket, establishing the maximum backlog of
1746 connections that is allowed. On success, continue to the next address. */
1747
1748 if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0)
1749 {
1750 #if defined(TCP_FASTOPEN) && defined(__APPLE__)
1751 if ( f.tcp_fastopen_ok
1752 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1753 &on, sizeof(on)))
1754 {
1755 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1756 f.tcp_fastopen_ok = FALSE;
1757 }
1758 #endif
1759 continue;
1760 }
1761
1762 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1763 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1764 and there was a previous successful IPv6 wildcard listen on the same port,
1765 we want to ignore the error on the grounds that we must be in a system
1766 where the IPv6 socket accepts both kinds of call. */
1767
1768 if (!check_special_case(errno, addresses, ipa, TRUE))
1769 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
1770 wildcard
1771 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
1772 strerror(errno));
1773
1774 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1775 "listen() success; EADDRINUSE ignored\n");
1776 (void)close(listen_sockets[sk]);
1777
1778 /* Come here if there has been a problem with the socket which we
1779 are going to ignore. We remove the address from the chain, and back up the
1780 counts. */
1781
1782 SKIP_SOCKET:
1783 sk--; /* Back up the count */
1784 listen_socket_count--; /* Reduce the total */
1785 if (ipa == addresses) addresses = ipa->next; else
1786 {
1787 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1788 ipa2->next = ipa->next;
1789 ipa = ipa2;
1790 }
1791 } /* End of bind/listen loop for each address */
1792 } /* End of setup for listening */
1793
1794
1795 /* If we are not listening, we want to write a pid file only if -oP was
1796 explicitly given. */
1797
1798 else if (!override_pid_file_path)
1799 write_pid = FALSE;
1800
1801 /* Write the pid to a known file for assistance in identification, if required.
1802 We do this before giving up root privilege, because on some systems it is
1803 necessary to be root in order to write into the pid file directory. There's
1804 nothing to stop multiple daemons running, as long as no more than one listens
1805 on a given TCP/IP port on the same interface(s). However, in these
1806 circumstances it gets far too complicated to mess with pid file names
1807 automatically. Consequently, Exim 4 writes a pid file only
1808
1809 (a) When running in the test harness, or
1810 (b) When -bd is used and -oX is not used, or
1811 (c) When -oP is used to supply a path.
1812
1813 The variable daemon_write_pid is used to control this. */
1814
1815 if (f.running_in_test_harness || write_pid)
1816 {
1817 FILE *f;
1818
1819 set_pid_file_path();
1820 if ((f = modefopen(pid_file_path, "wb", 0644)))
1821 {
1822 (void)fprintf(f, "%d\n", (int)getpid());
1823 (void)fclose(f);
1824 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1825 }
1826 else
1827 DEBUG(D_any)
1828 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
1829 pid_file_path));
1830 }
1831
1832 /* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1833
1834 sighup_seen = FALSE;
1835 signal(SIGHUP, sighup_handler);
1836
1837 /* Give up root privilege at this point (assuming that exim_uid and exim_gid
1838 are not root). The third argument controls the running of initgroups().
1839 Normally we do this, in order to set up the groups for the Exim user. However,
1840 if we are not root at this time - some odd installations run that way - we
1841 cannot do this. */
1842
1843 exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1844
1845 /* Update the originator_xxx fields so that received messages as listed as
1846 coming from Exim, not whoever started the daemon. */
1847
1848 originator_uid = exim_uid;
1849 originator_gid = exim_gid;
1850 originator_login = (pw = getpwuid(exim_uid))
1851 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
1852
1853 /* Get somewhere to keep the list of queue-runner pids if we are keeping track
1854 of them (and also if we are doing queue runs). */
1855
1856 if (queue_interval > 0 && local_queue_run_max > 0)
1857 {
1858 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t), FALSE);
1859 for (int i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
1860 }
1861
1862 /* Set up the handler for termination of child processes, and the one
1863 telling us to die. */
1864
1865 sigchld_seen = FALSE;
1866 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
1867
1868 sigterm_seen = FALSE;
1869 os_non_restarting_signal(SIGTERM, main_sigterm_handler);
1870
1871 /* If we are to run the queue periodically, pretend the alarm has just gone
1872 off. This will cause the first queue-runner to get kicked off straight away. */
1873
1874 sigalrm_seen = (queue_interval > 0);
1875
1876 /* Log the start up of a daemon - at least one of listening or queue running
1877 must be set up. */
1878
1879 if (f.inetd_wait_mode)
1880 {
1881 uschar *p = big_buffer;
1882
1883 if (inetd_wait_timeout >= 0)
1884 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
1885 else
1886 sprintf(CS p, "with no wait timeout");
1887
1888 log_write(0, LOG_MAIN,
1889 "exim %s daemon started: pid=%d, launched with listening socket, %s",
1890 version_string, getpid(), big_buffer);
1891 set_process_info("daemon(%s): pre-listening socket", version_string);
1892
1893 /* set up the timeout logic */
1894 sigalrm_seen = TRUE;
1895 }
1896
1897 else if (f.daemon_listen)
1898 {
1899 int smtp_ports = 0;
1900 int smtps_ports = 0;
1901 ip_address_item * ipa;
1902 uschar * p;
1903 uschar * qinfo = queue_interval > 0
1904 ? string_sprintf("-q%s", readconf_printtime(queue_interval))
1905 : US"no queue runs";
1906
1907 /* Build a list of listening addresses in big_buffer, but limit it to 10
1908 items. The style is for backwards compatibility.
1909
1910 It is now possible to have some ports listening for SMTPS (the old,
1911 deprecated protocol that starts TLS without using STARTTLS), and others
1912 listening for standard SMTP. Keep their listings separate. */
1913
1914 for (int j = 0, i; j < 2; j++)
1915 {
1916 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
1917 {
1918 /* First time round, look for SMTP ports; second time round, look for
1919 SMTPS ports. Build IP+port strings. */
1920
1921 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1922 {
1923 if (j == 0)
1924 smtp_ports++;
1925 else
1926 smtps_ports++;
1927
1928 /* Now the information about the port (and sometimes interface) */
1929
1930 if (ipa->address[0] == ':' && ipa->address[1] == 0)
1931 { /* v6 wildcard */
1932 if (ipa->next && ipa->next->address[0] == 0 &&
1933 ipa->next->port == ipa->port)
1934 {
1935 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
1936 (ipa = ipa->next)->log = NULL;
1937 }
1938 else if (ipa->v6_include_v4)
1939 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
1940 else
1941 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
1942 }
1943 else if (ipa->address[0] == 0) /* v4 wildcard */
1944 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
1945 else /* check for previously-seen IP */
1946 {
1947 ip_address_item * i2;
1948 for (i2 = addresses; i2 != ipa; i2 = i2->next)
1949 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
1950 && Ustrcmp(ipa->address, i2->address) == 0
1951 )
1952 { /* found; append port to list */
1953 for (p = i2->log; *p; ) p++; /* end of existing string */
1954 if (*--p == '}') *p = '\0'; /* drop EOL */
1955 while (isdigit(*--p)) ; /* char before port */
1956
1957 i2->log = *p == ':' /* no list yet? */
1958 ? string_sprintf("%.*s{%s,%d}",
1959 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
1960 : string_sprintf("%s,%d}", i2->log, ipa->port);
1961 ipa->log = NULL;
1962 break;
1963 }
1964 if (i2 == ipa) /* first-time IP */
1965 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
1966 }
1967 }
1968 }
1969 }
1970
1971 p = big_buffer;
1972 for (int j = 0, i; j < 2; j++)
1973 {
1974 /* First time round, look for SMTP ports; second time round, look for
1975 SMTPS ports. For the first one of each, insert leading text. */
1976
1977 if (j == 0)
1978 {
1979 if (smtp_ports > 0)
1980 p += sprintf(CS p, "SMTP on");
1981 }
1982 else
1983 if (smtps_ports > 0)
1984 p += sprintf(CS p, "%sSMTPS on",
1985 smtp_ports == 0 ? "" : " and for ");
1986
1987 /* Now the information about the port (and sometimes interface) */
1988
1989 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
1990 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1991 if (ipa->log)
1992 p += sprintf(CS p, "%s", ipa->log);
1993
1994 if (ipa)
1995 p += sprintf(CS p, " ...");
1996 }
1997
1998 log_write(0, LOG_MAIN,
1999 "exim %s daemon started: pid=%d, %s, listening for %s",
2000 version_string, getpid(), qinfo, big_buffer);
2001 set_process_info("daemon(%s): %s, listening for %s",
2002 version_string, qinfo, big_buffer);
2003 }
2004
2005 else
2006 {
2007 uschar * s = *queue_name
2008 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
2009 : string_sprintf("-q%s", readconf_printtime(queue_interval));
2010 log_write(0, LOG_MAIN,
2011 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
2012 version_string, getpid(), s);
2013 set_process_info("daemon(%s): %s, not listening", version_string, s);
2014 }
2015
2016 /* Do any work it might be useful to amortize over our children
2017 (eg: compile regex) */
2018
2019 dns_pattern_init();
2020 smtp_deliver_init(); /* Used for callouts */
2021
2022 #ifndef DISABLE_DKIM
2023 {
2024 # ifdef MEASURE_TIMING
2025 struct timeval t0;
2026 gettimeofday(&t0, NULL);
2027 # endif
2028 dkim_exim_init();
2029 # ifdef MEASURE_TIMING
2030 report_time_since(&t0, US"dkim_exim_init (delta)");
2031 # endif
2032 }
2033 #endif
2034
2035 #ifdef WITH_CONTENT_SCAN
2036 malware_init();
2037 #endif
2038 #ifdef SUPPORT_SPF
2039 spf_init();
2040 #endif
2041
2042 /* Close the log so it can be renamed and moved. In the few cases below where
2043 this long-running process writes to the log (always exceptional conditions), it
2044 closes the log afterwards, for the same reason. */
2045
2046 log_close_all();
2047
2048 DEBUG(D_any) debug_print_ids(US"daemon running with");
2049
2050 /* Any messages accepted via this route are going to be SMTP. */
2051
2052 smtp_input = TRUE;
2053
2054 #ifdef MEASURE_TIMING
2055 report_time_since(&timestamp_startup, US"daemon loop start"); /* testcase 0022 */
2056 #endif
2057
2058 /* Enter the never-ending loop... */
2059
2060 for (;;)
2061 {
2062 #if HAVE_IPV6
2063 struct sockaddr_in6 accepted;
2064 #else
2065 struct sockaddr_in accepted;
2066 #endif
2067
2068 EXIM_SOCKLEN_T len;
2069 pid_t pid;
2070
2071 if (sigterm_seen)
2072 daemon_die(); /* Does not return */
2073
2074 /* This code is placed first in the loop, so that it gets obeyed at the
2075 start, before the first wait, for the queue-runner case, so that the first
2076 one can be started immediately.
2077
2078 The other option is that we have an inetd wait timeout specified to -bw. */
2079
2080 if (sigalrm_seen)
2081 {
2082 if (inetd_wait_timeout > 0)
2083 {
2084 time_t resignal_interval = inetd_wait_timeout;
2085
2086 if (last_connection_time == (time_t)0)
2087 {
2088 DEBUG(D_any)
2089 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
2090 }
2091 else
2092 {
2093 time_t now = time(NULL);
2094 if (now == (time_t)-1)
2095 {
2096 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
2097 }
2098 else
2099 {
2100 if ((now - last_connection_time) >= inetd_wait_timeout)
2101 {
2102 DEBUG(D_any)
2103 debug_printf("inetd wait timeout %d expired, ending daemon\n",
2104 inetd_wait_timeout);
2105 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
2106 version_string);
2107 exit(EXIT_SUCCESS);
2108 }
2109 else
2110 {
2111 resignal_interval -= (now - last_connection_time);
2112 }
2113 }
2114 }
2115
2116 sigalrm_seen = FALSE;
2117 ALARM(resignal_interval);
2118 }
2119
2120 else
2121 {
2122 DEBUG(D_any) debug_printf("%s received\n",
2123 #ifdef EXPERIMENTAL_QUEUE_RAMP
2124 *queuerun_msgid ? "qrun notification" :
2125 #endif
2126 "SIGALRM");
2127
2128 /* Do a full queue run in a child process, if required, unless we already
2129 have enough queue runners on the go. If we are not running as root, a
2130 re-exec is required. */
2131
2132 if ( queue_interval > 0
2133 && (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
2134 {
2135 if ((pid = exim_fork(US"queue-runner")) == 0)
2136 {
2137 /* Disable debugging if it's required only for the daemon process. We
2138 leave the above message, because it ties up with the "child ended"
2139 debugging messages. */
2140
2141 if (f.debug_daemon) debug_selector = 0;
2142
2143 /* Close any open listening sockets in the child */
2144
2145 close_daemon_sockets(daemon_notifier_fd,
2146 listen_sockets, listen_socket_count);
2147
2148 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
2149
2150 signal(SIGHUP, SIG_DFL);
2151 signal(SIGCHLD, SIG_DFL);
2152 signal(SIGTERM, SIG_DFL);
2153
2154 /* Re-exec if privilege has been given up, unless deliver_drop_
2155 privilege is set. Reset SIGALRM before exec(). */
2156
2157 if (geteuid() != root_uid && !deliver_drop_privilege)
2158 {
2159 uschar opt[8];
2160 uschar *p = opt;
2161 uschar *extra[7];
2162 int extracount = 1;
2163
2164 signal(SIGALRM, SIG_DFL);
2165 *p++ = '-';
2166 *p++ = 'q';
2167 if ( f.queue_2stage
2168 #ifdef EXPERIMENTAL_QUEUE_RAMP
2169 && !*queuerun_msgid
2170 #endif
2171 ) *p++ = 'q';
2172 if (f.queue_run_first_delivery) *p++ = 'i';
2173 if (f.queue_run_force) *p++ = 'f';
2174 if (f.deliver_force_thaw) *p++ = 'f';
2175 if (f.queue_run_local) *p++ = 'l';
2176 *p = 0;
2177 extra[0] = *queue_name
2178 ? string_sprintf("%sG%s", opt, queue_name) : opt;
2179
2180 #ifdef EXPERIMENTAL_QUEUE_RAMP
2181 if (*queuerun_msgid)
2182 {
2183 log_write(0, LOG_MAIN, "notify triggered queue run");
2184 extra[extracount++] = queuerun_msgid; /* Trigger only the */
2185 extra[extracount++] = queuerun_msgid; /* one message */
2186 }
2187 #endif
2188
2189 /* If -R or -S were on the original command line, ensure they get
2190 passed on. */
2191
2192 if (deliver_selectstring)
2193 {
2194 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
2195 extra[extracount++] = deliver_selectstring;
2196 }
2197
2198 if (deliver_selectstring_sender)
2199 {
2200 extra[extracount++] = f.deliver_selectstring_sender_regex
2201 ? US"-Sr" : US"-S";
2202 extra[extracount++] = deliver_selectstring_sender;
2203 }
2204
2205 /* Overlay this process with a new execution. */
2206
2207 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
2208 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
2209
2210 /* Control never returns here. */
2211 }
2212
2213 /* No need to re-exec; SIGALRM remains set to the default handler */
2214
2215 #ifdef EXPERIMENTAL_QUEUE_RAMP
2216 if (*queuerun_msgid)
2217 {
2218 log_write(0, LOG_MAIN, "notify triggered queue run");
2219 f.queue_2stage = FALSE;
2220 queue_run(queuerun_msgid, queuerun_msgid, FALSE);
2221 }
2222 else
2223 #endif
2224 queue_run(NULL, NULL, FALSE);
2225 exim_underbar_exit(EXIT_SUCCESS);
2226 }
2227
2228 if (pid < 0)
2229 {
2230 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
2231 "process failed: %s", strerror(errno));
2232 log_close_all();
2233 }
2234 else
2235 {
2236 for (int i = 0; i < local_queue_run_max; ++i)
2237 if (queue_pid_slots[i] <= 0)
2238 {
2239 queue_pid_slots[i] = pid;
2240 queue_run_count++;
2241 break;
2242 }
2243 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
2244 queue_run_count, queue_run_count == 1 ? "" : "es");
2245 }
2246 }
2247
2248 /* Reset the alarm clock */
2249
2250 sigalrm_seen = FALSE;
2251 #ifdef EXPERIMENTAL_QUEUE_RAMP
2252 if (*queuerun_msgid)
2253 *queuerun_msgid = 0;
2254 else
2255 #endif
2256 ALARM(queue_interval);
2257 }
2258
2259 } /* sigalrm_seen */
2260
2261
2262 /* Sleep till a connection happens if listening, and handle the connection if
2263 that is why we woke up. The FreeBSD operating system requires the use of
2264 select() before accept() because the latter function is not interrupted by
2265 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2266 OS do notice signals in accept() but it does no harm to have the select()
2267 in for all of them - and it won't then be a lurking problem for ports to
2268 new OS. In fact, the later addition of listening on specific interfaces only
2269 requires this way of working anyway. */
2270
2271 if (f.daemon_listen)
2272 {
2273 int lcount, select_errno;
2274 int max_socket = 0;
2275 BOOL select_failed = FALSE;
2276 fd_set select_listen;
2277
2278 FD_ZERO(&select_listen);
2279 if (daemon_notifier_fd >= 0)
2280 FD_SET(daemon_notifier_fd, &select_listen);
2281 for (int sk = 0; sk < listen_socket_count; sk++)
2282 {
2283 FD_SET(listen_sockets[sk], &select_listen);
2284 if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk];
2285 }
2286
2287 DEBUG(D_any) debug_printf("Listening...\n");
2288
2289 /* In rare cases we may have had a SIGCHLD signal in the time between
2290 setting the handler (below) and getting back here. If so, pretend that the
2291 select() was interrupted so that we reap the child. This might still leave
2292 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
2293 only to do the reaping more quickly, it shouldn't result in anything other
2294 than a delay until something else causes a wake-up. */
2295
2296 if (sigchld_seen)
2297 {
2298 lcount = -1;
2299 errno = EINTR;
2300 }
2301 else
2302 lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen,
2303 NULL, NULL, NULL);
2304
2305 if (lcount < 0)
2306 {
2307 select_failed = TRUE;
2308 lcount = 1;
2309 }
2310
2311 /* Clean up any subprocesses that may have terminated. We need to do this
2312 here so that smtp_accept_max_per_host works when a connection to that host
2313 has completed, and we are about to accept a new one. When this code was
2314 later in the sequence, a new connection could be rejected, even though an
2315 old one had just finished. Preserve the errno from any select() failure for
2316 the use of the common select/accept error processing below. */
2317
2318 select_errno = errno;
2319 handle_ending_processes();
2320 errno = select_errno;
2321
2322 #ifndef DISABLE_TLS
2323 /* Create or rotate any required keys */
2324 tls_daemon_init();
2325 #endif
2326
2327 /* Loop for all the sockets that are currently ready to go. If select
2328 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2329 to use the common error code for select/accept below. */
2330
2331 while (lcount-- > 0)
2332 {
2333 int accept_socket = -1;
2334
2335 if (!select_failed)
2336 {
2337 if ( daemon_notifier_fd >= 0
2338 && FD_ISSET(daemon_notifier_fd, &select_listen))
2339 {
2340 FD_CLR(daemon_notifier_fd, &select_listen);
2341 sigalrm_seen = daemon_notification();
2342 break; /* to top of daemon loop */
2343 }
2344 for (int sk = 0; sk < listen_socket_count; sk++)
2345 if (FD_ISSET(listen_sockets[sk], &select_listen))
2346 {
2347 len = sizeof(accepted);
2348 accept_socket = accept(listen_sockets[sk],
2349 (struct sockaddr *)&accepted, &len);
2350 FD_CLR(listen_sockets[sk], &select_listen);
2351 break;
2352 }
2353 }
2354
2355 /* If select or accept has failed and this was not caused by an
2356 interruption, log the incident and try again. With asymmetric TCP/IP
2357 routing errors such as "No route to network" have been seen here. Also
2358 "connection reset by peer" has been seen. These cannot be classed as
2359 disastrous errors, but they could fill up a lot of log. The code in smail
2360 crashes the daemon after 10 successive failures of accept, on the grounds
2361 that some OS fail continuously. Exim originally followed suit, but this
2362 appears to have caused problems. Now it just keeps going, but instead of
2363 logging each error, it batches them up when they are continuous. */
2364
2365 if (accept_socket < 0 && errno != EINTR)
2366 {
2367 if (accept_retry_count == 0)
2368 {
2369 accept_retry_errno = errno;
2370 accept_retry_select_failed = select_failed;
2371 }
2372 else
2373 {
2374 if (errno != accept_retry_errno ||
2375 select_failed != accept_retry_select_failed ||
2376 accept_retry_count >= 50)
2377 {
2378 log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0),
2379 "%d %s() failure%s: %s",
2380 accept_retry_count,
2381 accept_retry_select_failed? "select" : "accept",
2382 (accept_retry_count == 1)? "" : "s",
2383 strerror(accept_retry_errno));
2384 log_close_all();
2385 accept_retry_count = 0;
2386 accept_retry_errno = errno;
2387 accept_retry_select_failed = select_failed;
2388 }
2389 }
2390 accept_retry_count++;
2391 }
2392
2393 else
2394 {
2395 if (accept_retry_count > 0)
2396 {
2397 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2398 accept_retry_count,
2399 accept_retry_select_failed? "select" : "accept",
2400 (accept_retry_count == 1)? "" : "s",
2401 strerror(accept_retry_errno));
2402 log_close_all();
2403 accept_retry_count = 0;
2404 }
2405 }
2406
2407 /* If select/accept succeeded, deal with the connection. */
2408
2409 if (accept_socket >= 0)
2410 {
2411 if (inetd_wait_timeout)
2412 last_connection_time = time(NULL);
2413 handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,
2414 (struct sockaddr *)&accepted);
2415 }
2416 }
2417 }
2418
2419 /* If not listening, then just sleep for the queue interval. If we woke
2420 up early the last time for some other signal, it won't matter because
2421 the alarm signal will wake at the right time. This code originally used
2422 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2423 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2424 select() can be used as an interruptible sleep() on all versions of Unix. */
2425
2426 else
2427 {
2428 struct timeval tv;
2429 tv.tv_sec = queue_interval;
2430 tv.tv_usec = 0;
2431 select(0, NULL, NULL, NULL, &tv);
2432 handle_ending_processes();
2433 }
2434
2435 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2436 for itself, because it isn't doing the waiting itself. */
2437
2438 if (sigchld_seen)
2439 {
2440 sigchld_seen = FALSE;
2441 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
2442 }
2443
2444 /* Handle being woken by SIGHUP. We know at this point that the result
2445 of accept() has been dealt with, so we can re-exec exim safely, first
2446 closing the listening sockets so that they can be reused. Cancel any pending
2447 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2448 that another HUP in quick succession doesn't clobber the new daemon before it
2449 gets going. All log files get closed by the close-on-exec flag; however, if
2450 the exec fails, we need to close the logs. */
2451
2452 if (sighup_seen)
2453 {
2454 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2455 getpid());
2456 close_daemon_sockets(daemon_notifier_fd,
2457 listen_sockets, listen_socket_count);
2458 ALARM_CLR(0);
2459 signal(SIGHUP, SIG_IGN);
2460 sighup_argv[0] = exim_path;
2461 exim_nullstd();
2462 execv(CS exim_path, (char *const *)sighup_argv);
2463 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2464 getpid(), exim_path, strerror(errno));
2465 log_close_all();
2466 }
2467
2468 } /* End of main loop */
2469
2470 /* Control never reaches here */
2471 }
2472
2473 /* vi: aw ai sw=2
2474 */
2475 /* End of exim_daemon.c */