Try to fix Solaris build
[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 = (void *)buf, /* ? cast needed for Solaris compiler */
1060 .iov_len = sizeof(buf)-1
1061 };
1062 struct msghdr msg = { .msg_name = &sa_un,
1063 .msg_namelen = sizeof(sa_un),
1064 .msg_iov = &iov,
1065 .msg_iovlen = 1,
1066 #if !defined(__sun)
1067 .msg_control = cbuf,
1068 .msg_controllen = sizeof(cbuf)
1069 #endif
1070 };
1071 ssize_t sz;
1072 struct cmsghdr * cp;
1073
1074 buf[sizeof(buf)-1] = 0;
1075 if ((sz = recvmsg(daemon_notifier_fd, &msg, 0)) <= 0) return FALSE;
1076 if (sz >= sizeof(buf)) return FALSE;
1077
1078 #ifdef notdef
1079 debug_printf("addrlen %d\n", msg.msg_namelen);
1080 #endif
1081 DEBUG(D_queue_run) debug_printf("%s from addr '%s%.*s'\n", __FUNCTION__,
1082 *sa_un.sun_path ? "" : "@",
1083 (int)msg.msg_namelen - (*sa_un.sun_path ? 0 : 1),
1084 sa_un.sun_path + (*sa_un.sun_path ? 0 : 1));
1085
1086 /* Refuse to handle the item unless the peer has good credentials */
1087 #ifdef SCM_CREDENTIALS
1088 # define EXIM_SCM_CR_TYPE SCM_CREDENTIALS
1089 #elif defined(LOCAL_CREDS) && defined(SCM_CREDS)
1090 # define EXIM_SCM_CR_TYPE SCM_CREDS
1091 #else
1092 /* The OS has no way to get the creds of the caller (for a unix/datagram socket.
1093 Punt; don't try to check. */
1094 #endif
1095
1096 #ifdef EXIM_SCM_CR_TYPE
1097 for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg);
1098 cp;
1099 cp = CMSG_NXTHDR(&msg, cp))
1100 if (cp->cmsg_level == SOL_SOCKET && cp->cmsg_type == EXIM_SCM_CR_TYPE)
1101 {
1102 # ifdef SCM_CREDENTIALS /* Linux */
1103 struct ucred * cr = (struct ucred *) CMSG_DATA(cp);
1104 if (cr->uid && cr->uid != exim_uid)
1105 {
1106 DEBUG(D_queue_run) debug_printf("%s: sender creds pid %d uid %d gid %d\n",
1107 __FUNCTION__, (int)cr->pid, (int)cr->uid, (int)cr->gid);
1108 return FALSE;
1109 }
1110 # elif defined(LOCAL_CREDS) /* BSD-ish */
1111 struct sockcred * cr = (struct sockcred *) CMSG_DATA(cp);
1112 if (cr->sc_uid && cr->sc_uid != exim_uid)
1113 {
1114 DEBUG(D_queue_run) debug_printf("%s: sender creds pid ??? uid %d gid %d\n",
1115 __FUNCTION__, (int)cr->sc_uid, (int)cr->sc_gid);
1116 return FALSE;
1117 }
1118 # endif
1119 break;
1120 }
1121 #endif
1122
1123 buf[sz] = 0;
1124 switch (buf[0])
1125 {
1126 #ifdef EXPERIMENTAL_QUEUE_RAMP
1127 case NOTIFY_MSG_QRUN:
1128 /* this should be a message_id */
1129 DEBUG(D_queue_run)
1130 debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1);
1131 memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1);
1132 return TRUE;
1133 #endif /*EXPERIMENTAL_QUEUE_RAMP*/
1134
1135 case NOTIFY_QUEUE_SIZE_REQ:
1136 {
1137 uschar buf[16];
1138 int len = snprintf(CS buf, sizeof(buf), "%u", queue_count_cached());
1139
1140 DEBUG(D_queue_run)
1141 debug_printf("%s: queue size request: %s\n", __FUNCTION__, buf);
1142
1143 if (sendto(daemon_notifier_fd, buf, len, 0,
1144 (const struct sockaddr *)&sa_un, msg.msg_namelen) < 0)
1145 log_write(0, LOG_MAIN|LOG_PANIC,
1146 "%s: sendto: %s\n", __FUNCTION__, strerror(errno));
1147 return FALSE;
1148 }
1149 }
1150 return FALSE;
1151 }
1152
1153
1154 /*************************************************
1155 * Exim Daemon Mainline *
1156 *************************************************/
1157
1158 /* The daemon can do two jobs, either of which is optional:
1159
1160 (1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1161 each one. This is requested by the -bd option, with -oX specifying the SMTP
1162 port on which to listen (for testing).
1163
1164 (2) Spawns a queue-running process every so often. This is controlled by the
1165 -q option with a an interval time. (If no time is given, a single queue run
1166 is done from the main function, and control doesn't get here.)
1167
1168 Root privilege is required in order to attach to port 25. Some systems require
1169 it when calling socket() rather than bind(). To cope with all cases, we run as
1170 root for both socket() and bind(). Some systems also require root in order to
1171 write to the pid file directory. This function must therefore be called as root
1172 if it is to work properly in all circumstances. Once the socket is bound and
1173 the pid file written, root privilege is given up if there is an exim uid.
1174
1175 There are no arguments to this function, and it never returns. */
1176
1177 void
1178 daemon_go(void)
1179 {
1180 struct passwd *pw;
1181 int *listen_sockets = NULL;
1182 int listen_socket_count = 0;
1183 ip_address_item *addresses = NULL;
1184 time_t last_connection_time = (time_t)0;
1185 int local_queue_run_max = atoi(CS expand_string(queue_run_max));
1186
1187 /* If any debugging options are set, turn on the D_pid bit so that all
1188 debugging lines get the pid added. */
1189
1190 DEBUG(D_any|D_v) debug_selector |= D_pid;
1191
1192 if (f.inetd_wait_mode)
1193 {
1194 listen_socket_count = 1;
1195 listen_sockets = store_get(sizeof(int), FALSE);
1196 (void) close(3);
1197 if (dup2(0, 3) == -1)
1198 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1199 "failed to dup inetd socket safely away: %s", strerror(errno));
1200
1201 listen_sockets[0] = 3;
1202 (void) close(0);
1203 (void) close(1);
1204 (void) close(2);
1205 exim_nullstd();
1206
1207 if (debug_file == stderr)
1208 {
1209 /* need a call to log_write before call to open debug_file, so that
1210 log.c:file_path has been initialised. This is unfortunate. */
1211 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1212
1213 fclose(debug_file);
1214 debug_file = NULL;
1215 exim_nullstd(); /* re-open fd2 after we just closed it again */
1216 debug_logging_activate(US"-wait", NULL);
1217 }
1218
1219 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1220
1221 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1222 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1223
1224 if (tcp_nodelay)
1225 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1226 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1227 strerror(errno));
1228 }
1229
1230
1231 if (f.inetd_wait_mode || f.daemon_listen)
1232 {
1233 /* If any option requiring a load average to be available during the
1234 reception of a message is set, call os_getloadavg() while we are root
1235 for those OS for which this is necessary the first time it is called (in
1236 order to perform an "open" on the kernel memory file). */
1237
1238 #ifdef LOAD_AVG_NEEDS_ROOT
1239 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1240 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1241 (void)os_getloadavg();
1242 #endif
1243 }
1244
1245
1246 /* Do the preparation for setting up a listener on one or more interfaces, and
1247 possible on various ports. This is controlled by the combination of
1248 local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1249 (which is a list of default ports to use for those items in local_interfaces
1250 that do not specify a port). The -oX command line option can be used to
1251 override one or both of these options.
1252
1253 If local_interfaces is not set, the default is to listen on all interfaces.
1254 When it is set, it can include "all IPvx interfaces" as an item. This is useful
1255 when different ports are in use.
1256
1257 It turns out that listening on all interfaces is messy in an IPv6 world,
1258 because several different implementation approaches have been taken. This code
1259 is now supposed to work with all of them. The point of difference is whether an
1260 IPv6 socket that is listening on all interfaces will receive incoming IPv4
1261 calls or not. We also have to cope with the case when IPv6 libraries exist, but
1262 there is no IPv6 support in the kernel.
1263
1264 . On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1265 addresses. However, if an IPv4 socket is also listening on all interfaces,
1266 calls are directed to the appropriate socket.
1267
1268 . On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1269 give them as mapped addresses, but an attempt also to listen on an IPv4
1270 socket on all interfaces causes an error.
1271
1272 . On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1273 two sockets if you want to accept both kinds of call.
1274
1275 . FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1276 can be turned off, to make it behave like the versions of Linux described
1277 above.
1278
1279 . I heard a report that the USAGI IPv6 stack for Linux has implemented
1280 IPV6_V6ONLY.
1281
1282 So, what we do when IPv6 is supported is as follows:
1283
1284 (1) After it is set up, the list of interfaces is scanned for wildcard
1285 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1286 port, the list is re-arranged so that they are together, with the IPv6
1287 wildcard first.
1288
1289 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1290 carry on if an IPv4 wildcard socket for the same port follows later in the
1291 list. This allows Exim to carry on in the case when the kernel has no IPv6
1292 support.
1293
1294 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1295 option is defined. However, if setting fails, carry on regardless (but log
1296 the incident).
1297
1298 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1299 error.
1300
1301 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1302 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1303 port (which must have succeeded or we wouldn't have got this far), we
1304 assume we are in the situation where just a single socket is permitted,
1305 and ignore the error.
1306
1307 Phew!
1308
1309 The preparation code decodes options and sets up the relevant data. We do this
1310 first, so that we can return non-zero if there are any syntax errors, and also
1311 write to stderr. */
1312
1313 if (f.daemon_listen && !f.inetd_wait_mode)
1314 {
1315 int *default_smtp_port;
1316 int sep;
1317 int pct = 0;
1318 uschar *s;
1319 const uschar * list;
1320 uschar *local_iface_source = US"local_interfaces";
1321 ip_address_item *ipa;
1322 ip_address_item **pipa;
1323
1324 /* If -oX was used, disable the writing of a pid file unless -oP was
1325 explicitly used to force it. Then scan the string given to -oX. Any items
1326 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1327 Any other items are used to override local_interfaces. */
1328
1329 if (override_local_interfaces)
1330 {
1331 gstring * new_smtp_port = NULL;
1332 gstring * new_local_interfaces = NULL;
1333
1334 if (!override_pid_file_path) write_pid = FALSE;
1335
1336 list = override_local_interfaces;
1337 sep = 0;
1338 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1339 {
1340 uschar joinstr[4];
1341 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
1342
1343 if (!*gp)
1344 {
1345 joinstr[0] = sep;
1346 joinstr[1] = ' ';
1347 *gp = string_catn(*gp, US"<", 1);
1348 }
1349
1350 *gp = string_catn(*gp, joinstr, 2);
1351 *gp = string_cat (*gp, s);
1352 }
1353
1354 if (new_smtp_port)
1355 {
1356 daemon_smtp_port = string_from_gstring(new_smtp_port);
1357 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1358 daemon_smtp_port);
1359 }
1360
1361 if (new_local_interfaces)
1362 {
1363 local_interfaces = string_from_gstring(new_local_interfaces);
1364 local_iface_source = US"-oX data";
1365 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1366 local_interfaces);
1367 }
1368 }
1369
1370 /* Create a list of default SMTP ports, to be used if local_interfaces
1371 contains entries without explicit ports. First count the number of ports, then
1372 build a translated list in a vector. */
1373
1374 list = daemon_smtp_port;
1375 sep = 0;
1376 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1377 pct++;
1378 default_smtp_port = store_get((pct+1) * sizeof(int), FALSE);
1379 list = daemon_smtp_port;
1380 sep = 0;
1381 for (pct = 0;
1382 (s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size));
1383 pct++)
1384 {
1385 if (isdigit(*s))
1386 {
1387 uschar *end;
1388 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1389 if (end != s + Ustrlen(s))
1390 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1391 }
1392 else
1393 {
1394 struct servent *smtp_service = getservbyname(CS s, "tcp");
1395 if (!smtp_service)
1396 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1397 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1398 }
1399 }
1400 default_smtp_port[pct] = 0;
1401
1402 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1403
1404 list = tls_in.on_connect_ports;
1405 sep = 0;
1406 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1407 if (!isdigit(*s))
1408 {
1409 gstring * g = NULL;
1410
1411 list = tls_in.on_connect_ports;
1412 tls_in.on_connect_ports = NULL;
1413 sep = 0;
1414 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1415 {
1416 if (!isdigit(*s))
1417 {
1418 struct servent * smtp_service = getservbyname(CS s, "tcp");
1419 if (!smtp_service)
1420 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1421 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
1422 }
1423 g = string_append_listele(g, ':', s);
1424 }
1425 if (g)
1426 tls_in.on_connect_ports = g->s;
1427 break;
1428 }
1429
1430 /* Create the list of local interfaces, possibly with ports included. This
1431 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1432 values are converted below. */
1433
1434 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1435
1436 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1437 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1438 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1439 anyway, but we need to know which are the wildcard addresses, and the shorter
1440 strings are neater.
1441
1442 In the same scan, fill in missing port numbers from the default list. When
1443 there is more than one item in the list, extra items are created. */
1444
1445 for (ipa = addresses; ipa; ipa = ipa->next)
1446 {
1447 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1448 ipa->address[0] = 0;
1449 else if (Ustrcmp(ipa->address, "::0") == 0)
1450 {
1451 ipa->address[0] = ':';
1452 ipa->address[1] = 0;
1453 }
1454
1455 if (ipa->port > 0) continue;
1456
1457 if (daemon_smtp_port[0] <= 0)
1458 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1459 "%s and daemon_smtp_port is unset; cannot start daemon",
1460 ipa->address[0] == 0 ? US"\"all IPv4\"" :
1461 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
1462
1463 ipa->port = default_smtp_port[0];
1464 for (int i = 1; default_smtp_port[i] > 0; i++)
1465 {
1466 ip_address_item *new = store_get(sizeof(ip_address_item), FALSE);
1467
1468 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1469 new->port = default_smtp_port[i];
1470 new->next = ipa->next;
1471 ipa->next = new;
1472 ipa = new;
1473 }
1474 }
1475
1476 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1477 wildcard for the same port, ensure that (a) they are together and (b) the
1478 IPv6 address comes first. This makes handling the messy features easier, and
1479 also simplifies the construction of the "daemon started" log line. */
1480
1481 pipa = &addresses;
1482 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
1483 {
1484 ip_address_item *ipa2;
1485
1486 /* Handle an IPv4 wildcard */
1487
1488 if (ipa->address[0] == 0)
1489 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1490 {
1491 ip_address_item *ipa3 = ipa2->next;
1492 if (ipa3->address[0] == ':' &&
1493 ipa3->address[1] == 0 &&
1494 ipa3->port == ipa->port)
1495 {
1496 ipa2->next = ipa3->next;
1497 ipa3->next = ipa;
1498 *pipa = ipa3;
1499 break;
1500 }
1501 }
1502
1503 /* Handle an IPv6 wildcard. */
1504
1505 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
1506 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1507 {
1508 ip_address_item *ipa3 = ipa2->next;
1509 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1510 {
1511 ipa2->next = ipa3->next;
1512 ipa3->next = ipa->next;
1513 ipa->next = ipa3;
1514 ipa = ipa3;
1515 break;
1516 }
1517 }
1518 }
1519
1520 /* Get a vector to remember all the sockets in */
1521
1522 for (ipa = addresses; ipa; ipa = ipa->next)
1523 listen_socket_count++;
1524 listen_sockets = store_get(sizeof(int) * listen_socket_count, FALSE);
1525
1526 } /* daemon_listen but not inetd_wait_mode */
1527
1528 if (f.daemon_listen)
1529 {
1530
1531 /* Do a sanity check on the max connects value just to save us from getting
1532 a huge amount of store. */
1533
1534 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1535
1536 /* There's no point setting smtp_accept_queue unless it is less than the max
1537 connects limit. The configuration reader ensures that the max is set if the
1538 queue-only option is set. */
1539
1540 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1541
1542 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1543 track of them for total number and queue/host limits. */
1544
1545 if (smtp_accept_max > 0)
1546 {
1547 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), FALSE);
1548 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
1549 }
1550 }
1551
1552 /* The variable background_daemon is always false when debugging, but
1553 can also be forced false in order to keep a non-debugging daemon in the
1554 foreground. If background_daemon is true, close all open file descriptors that
1555 we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1556 do this for inetd_wait mode.
1557
1558 This is protection against any called functions (in libraries, or in
1559 Perl, or whatever) that think they can write to stderr (or stdout). Before this
1560 was added, it was quite likely that an SMTP connection would use one of these
1561 file descriptors, in which case writing random stuff to it caused chaos.
1562
1563 Then disconnect from the controlling terminal, Most modern Unixes seem to have
1564 setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1565 setsid() can be #defined as a no-op, or as something else. */
1566
1567 if (f.background_daemon || f.inetd_wait_mode)
1568 {
1569 log_close_all(); /* Just in case anything was logged earlier */
1570 search_tidyup(); /* Just in case any were used in reading the config. */
1571 (void)close(0); /* Get rid of stdin/stdout/stderr */
1572 (void)close(1);
1573 (void)close(2);
1574 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
1575 log_stderr = NULL; /* So no attempt to copy paniclog output */
1576 }
1577
1578 if (f.background_daemon)
1579 {
1580 /* If the parent process of this one has pid == 1, we are re-initializing the
1581 daemon as the result of a SIGHUP. In this case, there is no need to do
1582 anything, because the controlling terminal has long gone. Otherwise, fork, in
1583 case current process is a process group leader (see 'man setsid' for an
1584 explanation) before calling setsid(). */
1585
1586 if (getppid() != 1)
1587 {
1588 pid_t pid = fork();
1589 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1590 "fork() failed when starting daemon: %s", strerror(errno));
1591 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1592 (void)setsid(); /* release controlling terminal */
1593 }
1594 }
1595
1596 /* We are now in the disconnected, daemon process (unless debugging). Set up
1597 the listening sockets if required. */
1598
1599 daemon_notifier_socket();
1600
1601 if (f.daemon_listen && !f.inetd_wait_mode)
1602 {
1603 int sk;
1604 ip_address_item *ipa;
1605
1606 /* For each IP address, create a socket, bind it to the appropriate port, and
1607 start listening. See comments above about IPv6 sockets that may or may not
1608 accept IPv4 calls when listening on all interfaces. We also have to cope with
1609 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1610 listening, provided a wildcard IPv4 socket for the same port follows. */
1611
1612 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1613 {
1614 BOOL wildcard;
1615 ip_address_item *ipa2;
1616 int af;
1617
1618 if (Ustrchr(ipa->address, ':') != NULL)
1619 {
1620 af = AF_INET6;
1621 wildcard = ipa->address[1] == 0;
1622 }
1623 else
1624 {
1625 af = AF_INET;
1626 wildcard = ipa->address[0] == 0;
1627 }
1628
1629 if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0)
1630 {
1631 if (check_special_case(0, addresses, ipa, FALSE))
1632 {
1633 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1634 "listening (%s): will use IPv4", strerror(errno));
1635 goto SKIP_SOCKET;
1636 }
1637 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1638 (af == AF_INET6)? '6' : '4', strerror(errno));
1639 }
1640
1641 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1642 available. Just log failure (can get protocol not available, just like
1643 socket creation can). */
1644
1645 #ifdef IPV6_V6ONLY
1646 if (af == AF_INET6 && wildcard &&
1647 setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, CS (&on),
1648 sizeof(on)) < 0)
1649 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1650 "socket failed (%s): carrying on without it", strerror(errno));
1651 #endif /* IPV6_V6ONLY */
1652
1653 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1654 is being handled. Without this, a connection will prevent reuse of the
1655 smtp port for listening. */
1656
1657 if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR,
1658 US (&on), sizeof(on)) < 0)
1659 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1660 "failed when starting daemon: %s", strerror(errno));
1661
1662 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1663 disable this because it breaks some broken clients. */
1664
1665 if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY,
1666 US (&on), sizeof(on));
1667
1668 /* Now bind the socket to the required port; if Exim is being restarted
1669 it may not always be possible to bind immediately, even with SO_REUSEADDR
1670 set, so try 10 times, waiting between each try. After 10 failures, we give
1671 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1672 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1673 address for the same port, ignore the error on the grounds that we must be
1674 in a system where the IPv6 socket accepts both kinds of call. This is
1675 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1676 listen() stage instead. */
1677
1678 #ifdef TCP_FASTOPEN
1679 f.tcp_fastopen_ok = TRUE;
1680 #endif
1681 for(;;)
1682 {
1683 uschar *msg, *addr;
1684 if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break;
1685 if (check_special_case(errno, addresses, ipa, TRUE))
1686 {
1687 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1688 "listen() success; EADDRINUSE ignored\n");
1689 (void)close(listen_sockets[sk]);
1690 goto SKIP_SOCKET;
1691 }
1692 msg = US strerror(errno);
1693 addr = wildcard
1694 ? af == AF_INET6
1695 ? US"(any IPv6)"
1696 : US"(any IPv4)"
1697 : ipa->address;
1698 if (daemon_startup_retries <= 0)
1699 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1700 "socket bind() to port %d for address %s failed: %s: "
1701 "daemon abandoned", ipa->port, addr, msg);
1702 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
1703 "failed: %s: waiting %s before trying again (%d more %s)",
1704 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1705 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1706 daemon_startup_retries--;
1707 sleep(daemon_startup_sleep);
1708 }
1709
1710 DEBUG(D_any)
1711 if (wildcard)
1712 debug_printf("listening on all interfaces (IPv%c) port %d\n",
1713 af == AF_INET6 ? '6' : '4', ipa->port);
1714 else
1715 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
1716
1717 #if defined(TCP_FASTOPEN) && !defined(__APPLE__)
1718 if ( f.tcp_fastopen_ok
1719 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1720 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
1721 {
1722 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1723 f.tcp_fastopen_ok = FALSE;
1724 }
1725 #endif
1726
1727 /* Start listening on the bound socket, establishing the maximum backlog of
1728 connections that is allowed. On success, continue to the next address. */
1729
1730 if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0)
1731 {
1732 #if defined(TCP_FASTOPEN) && defined(__APPLE__)
1733 if ( f.tcp_fastopen_ok
1734 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1735 &on, sizeof(on)))
1736 {
1737 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1738 f.tcp_fastopen_ok = FALSE;
1739 }
1740 #endif
1741 continue;
1742 }
1743
1744 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1745 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1746 and there was a previous successful IPv6 wildcard listen on the same port,
1747 we want to ignore the error on the grounds that we must be in a system
1748 where the IPv6 socket accepts both kinds of call. */
1749
1750 if (!check_special_case(errno, addresses, ipa, TRUE))
1751 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
1752 wildcard
1753 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
1754 strerror(errno));
1755
1756 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1757 "listen() success; EADDRINUSE ignored\n");
1758 (void)close(listen_sockets[sk]);
1759
1760 /* Come here if there has been a problem with the socket which we
1761 are going to ignore. We remove the address from the chain, and back up the
1762 counts. */
1763
1764 SKIP_SOCKET:
1765 sk--; /* Back up the count */
1766 listen_socket_count--; /* Reduce the total */
1767 if (ipa == addresses) addresses = ipa->next; else
1768 {
1769 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1770 ipa2->next = ipa->next;
1771 ipa = ipa2;
1772 }
1773 } /* End of bind/listen loop for each address */
1774 } /* End of setup for listening */
1775
1776
1777 /* If we are not listening, we want to write a pid file only if -oP was
1778 explicitly given. */
1779
1780 else if (!override_pid_file_path)
1781 write_pid = FALSE;
1782
1783 /* Write the pid to a known file for assistance in identification, if required.
1784 We do this before giving up root privilege, because on some systems it is
1785 necessary to be root in order to write into the pid file directory. There's
1786 nothing to stop multiple daemons running, as long as no more than one listens
1787 on a given TCP/IP port on the same interface(s). However, in these
1788 circumstances it gets far too complicated to mess with pid file names
1789 automatically. Consequently, Exim 4 writes a pid file only
1790
1791 (a) When running in the test harness, or
1792 (b) When -bd is used and -oX is not used, or
1793 (c) When -oP is used to supply a path.
1794
1795 The variable daemon_write_pid is used to control this. */
1796
1797 if (f.running_in_test_harness || write_pid)
1798 {
1799 FILE *f;
1800
1801 set_pid_file_path();
1802 if ((f = modefopen(pid_file_path, "wb", 0644)))
1803 {
1804 (void)fprintf(f, "%d\n", (int)getpid());
1805 (void)fclose(f);
1806 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1807 }
1808 else
1809 DEBUG(D_any)
1810 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
1811 pid_file_path));
1812 }
1813
1814 /* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1815
1816 sighup_seen = FALSE;
1817 signal(SIGHUP, sighup_handler);
1818
1819 /* Give up root privilege at this point (assuming that exim_uid and exim_gid
1820 are not root). The third argument controls the running of initgroups().
1821 Normally we do this, in order to set up the groups for the Exim user. However,
1822 if we are not root at this time - some odd installations run that way - we
1823 cannot do this. */
1824
1825 exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1826
1827 /* Update the originator_xxx fields so that received messages as listed as
1828 coming from Exim, not whoever started the daemon. */
1829
1830 originator_uid = exim_uid;
1831 originator_gid = exim_gid;
1832 originator_login = (pw = getpwuid(exim_uid))
1833 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
1834
1835 /* Get somewhere to keep the list of queue-runner pids if we are keeping track
1836 of them (and also if we are doing queue runs). */
1837
1838 if (queue_interval > 0 && local_queue_run_max > 0)
1839 {
1840 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t), FALSE);
1841 for (int i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
1842 }
1843
1844 /* Set up the handler for termination of child processes, and the one
1845 telling us to die. */
1846
1847 sigchld_seen = FALSE;
1848 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
1849
1850 sigterm_seen = FALSE;
1851 os_non_restarting_signal(SIGTERM, main_sigterm_handler);
1852
1853 /* If we are to run the queue periodically, pretend the alarm has just gone
1854 off. This will cause the first queue-runner to get kicked off straight away. */
1855
1856 sigalrm_seen = (queue_interval > 0);
1857
1858 /* Log the start up of a daemon - at least one of listening or queue running
1859 must be set up. */
1860
1861 if (f.inetd_wait_mode)
1862 {
1863 uschar *p = big_buffer;
1864
1865 if (inetd_wait_timeout >= 0)
1866 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
1867 else
1868 sprintf(CS p, "with no wait timeout");
1869
1870 log_write(0, LOG_MAIN,
1871 "exim %s daemon started: pid=%d, launched with listening socket, %s",
1872 version_string, getpid(), big_buffer);
1873 set_process_info("daemon(%s): pre-listening socket", version_string);
1874
1875 /* set up the timeout logic */
1876 sigalrm_seen = TRUE;
1877 }
1878
1879 else if (f.daemon_listen)
1880 {
1881 int smtp_ports = 0;
1882 int smtps_ports = 0;
1883 ip_address_item * ipa;
1884 uschar * p;
1885 uschar * qinfo = queue_interval > 0
1886 ? string_sprintf("-q%s", readconf_printtime(queue_interval))
1887 : US"no queue runs";
1888
1889 /* Build a list of listening addresses in big_buffer, but limit it to 10
1890 items. The style is for backwards compatibility.
1891
1892 It is now possible to have some ports listening for SMTPS (the old,
1893 deprecated protocol that starts TLS without using STARTTLS), and others
1894 listening for standard SMTP. Keep their listings separate. */
1895
1896 for (int j = 0, i; j < 2; j++)
1897 {
1898 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
1899 {
1900 /* First time round, look for SMTP ports; second time round, look for
1901 SMTPS ports. Build IP+port strings. */
1902
1903 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1904 {
1905 if (j == 0)
1906 smtp_ports++;
1907 else
1908 smtps_ports++;
1909
1910 /* Now the information about the port (and sometimes interface) */
1911
1912 if (ipa->address[0] == ':' && ipa->address[1] == 0)
1913 { /* v6 wildcard */
1914 if (ipa->next && ipa->next->address[0] == 0 &&
1915 ipa->next->port == ipa->port)
1916 {
1917 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
1918 (ipa = ipa->next)->log = NULL;
1919 }
1920 else if (ipa->v6_include_v4)
1921 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
1922 else
1923 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
1924 }
1925 else if (ipa->address[0] == 0) /* v4 wildcard */
1926 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
1927 else /* check for previously-seen IP */
1928 {
1929 ip_address_item * i2;
1930 for (i2 = addresses; i2 != ipa; i2 = i2->next)
1931 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
1932 && Ustrcmp(ipa->address, i2->address) == 0
1933 )
1934 { /* found; append port to list */
1935 for (p = i2->log; *p; ) p++; /* end of existing string */
1936 if (*--p == '}') *p = '\0'; /* drop EOL */
1937 while (isdigit(*--p)) ; /* char before port */
1938
1939 i2->log = *p == ':' /* no list yet? */
1940 ? string_sprintf("%.*s{%s,%d}",
1941 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
1942 : string_sprintf("%s,%d}", i2->log, ipa->port);
1943 ipa->log = NULL;
1944 break;
1945 }
1946 if (i2 == ipa) /* first-time IP */
1947 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
1948 }
1949 }
1950 }
1951 }
1952
1953 p = big_buffer;
1954 for (int j = 0, i; j < 2; j++)
1955 {
1956 /* First time round, look for SMTP ports; second time round, look for
1957 SMTPS ports. For the first one of each, insert leading text. */
1958
1959 if (j == 0)
1960 {
1961 if (smtp_ports > 0)
1962 p += sprintf(CS p, "SMTP on");
1963 }
1964 else
1965 if (smtps_ports > 0)
1966 p += sprintf(CS p, "%sSMTPS on",
1967 smtp_ports == 0 ? "" : " and for ");
1968
1969 /* Now the information about the port (and sometimes interface) */
1970
1971 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
1972 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1973 if (ipa->log)
1974 p += sprintf(CS p, "%s", ipa->log);
1975
1976 if (ipa)
1977 p += sprintf(CS p, " ...");
1978 }
1979
1980 log_write(0, LOG_MAIN,
1981 "exim %s daemon started: pid=%d, %s, listening for %s",
1982 version_string, getpid(), qinfo, big_buffer);
1983 set_process_info("daemon(%s): %s, listening for %s",
1984 version_string, qinfo, big_buffer);
1985 }
1986
1987 else
1988 {
1989 uschar * s = *queue_name
1990 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
1991 : string_sprintf("-q%s", readconf_printtime(queue_interval));
1992 log_write(0, LOG_MAIN,
1993 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
1994 version_string, getpid(), s);
1995 set_process_info("daemon(%s): %s, not listening", version_string, s);
1996 }
1997
1998 /* Do any work it might be useful to amortize over our children
1999 (eg: compile regex) */
2000
2001 dns_pattern_init();
2002 smtp_deliver_init(); /* Used for callouts */
2003
2004 #ifndef DISABLE_DKIM
2005 {
2006 # ifdef MEASURE_TIMING
2007 struct timeval t0;
2008 gettimeofday(&t0, NULL);
2009 # endif
2010 dkim_exim_init();
2011 # ifdef MEASURE_TIMING
2012 report_time_since(&t0, US"dkim_exim_init (delta)");
2013 # endif
2014 }
2015 #endif
2016
2017 #ifdef WITH_CONTENT_SCAN
2018 malware_init();
2019 #endif
2020 #ifdef SUPPORT_SPF
2021 spf_init();
2022 #endif
2023
2024 /* Close the log so it can be renamed and moved. In the few cases below where
2025 this long-running process writes to the log (always exceptional conditions), it
2026 closes the log afterwards, for the same reason. */
2027
2028 log_close_all();
2029
2030 DEBUG(D_any) debug_print_ids(US"daemon running with");
2031
2032 /* Any messages accepted via this route are going to be SMTP. */
2033
2034 smtp_input = TRUE;
2035
2036 #ifdef MEASURE_TIMING
2037 report_time_since(&timestamp_startup, US"daemon loop start"); /* testcase 0022 */
2038 #endif
2039
2040 /* Enter the never-ending loop... */
2041
2042 for (;;)
2043 {
2044 #if HAVE_IPV6
2045 struct sockaddr_in6 accepted;
2046 #else
2047 struct sockaddr_in accepted;
2048 #endif
2049
2050 EXIM_SOCKLEN_T len;
2051 pid_t pid;
2052
2053 if (sigterm_seen)
2054 daemon_die(); /* Does not return */
2055
2056 /* This code is placed first in the loop, so that it gets obeyed at the
2057 start, before the first wait, for the queue-runner case, so that the first
2058 one can be started immediately.
2059
2060 The other option is that we have an inetd wait timeout specified to -bw. */
2061
2062 if (sigalrm_seen)
2063 {
2064 if (inetd_wait_timeout > 0)
2065 {
2066 time_t resignal_interval = inetd_wait_timeout;
2067
2068 if (last_connection_time == (time_t)0)
2069 {
2070 DEBUG(D_any)
2071 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
2072 }
2073 else
2074 {
2075 time_t now = time(NULL);
2076 if (now == (time_t)-1)
2077 {
2078 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
2079 }
2080 else
2081 {
2082 if ((now - last_connection_time) >= inetd_wait_timeout)
2083 {
2084 DEBUG(D_any)
2085 debug_printf("inetd wait timeout %d expired, ending daemon\n",
2086 inetd_wait_timeout);
2087 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
2088 version_string);
2089 exit(EXIT_SUCCESS);
2090 }
2091 else
2092 {
2093 resignal_interval -= (now - last_connection_time);
2094 }
2095 }
2096 }
2097
2098 sigalrm_seen = FALSE;
2099 ALARM(resignal_interval);
2100 }
2101
2102 else
2103 {
2104 DEBUG(D_any) debug_printf("%s received\n",
2105 #ifdef EXPERIMENTAL_QUEUE_RAMP
2106 *queuerun_msgid ? "qrun notification" :
2107 #endif
2108 "SIGALRM");
2109
2110 /* Do a full queue run in a child process, if required, unless we already
2111 have enough queue runners on the go. If we are not running as root, a
2112 re-exec is required. */
2113
2114 if (queue_interval > 0 &&
2115 (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
2116 {
2117 if ((pid = fork()) == 0)
2118 {
2119 DEBUG(D_any) debug_printf("Starting queue-runner: pid %d\n",
2120 (int)getpid());
2121
2122 /* Disable debugging if it's required only for the daemon process. We
2123 leave the above message, because it ties up with the "child ended"
2124 debugging messages. */
2125
2126 if (f.debug_daemon) debug_selector = 0;
2127
2128 /* Close any open listening sockets in the child */
2129
2130 if (daemon_notifier_fd >= 0)
2131 (void) close(daemon_notifier_fd);
2132 for (int sk = 0; sk < listen_socket_count; sk++)
2133 (void) close(listen_sockets[sk]);
2134
2135 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
2136
2137 signal(SIGHUP, SIG_DFL);
2138 signal(SIGCHLD, SIG_DFL);
2139 signal(SIGTERM, SIG_DFL);
2140
2141 /* Re-exec if privilege has been given up, unless deliver_drop_
2142 privilege is set. Reset SIGALRM before exec(). */
2143
2144 if (geteuid() != root_uid && !deliver_drop_privilege)
2145 {
2146 uschar opt[8];
2147 uschar *p = opt;
2148 uschar *extra[7];
2149 int extracount = 1;
2150
2151 signal(SIGALRM, SIG_DFL);
2152 *p++ = '-';
2153 *p++ = 'q';
2154 if ( f.queue_2stage
2155 #ifdef EXPERIMENTAL_QUEUE_RAMP
2156 && !*queuerun_msgid
2157 #endif
2158 ) *p++ = 'q';
2159 if (f.queue_run_first_delivery) *p++ = 'i';
2160 if (f.queue_run_force) *p++ = 'f';
2161 if (f.deliver_force_thaw) *p++ = 'f';
2162 if (f.queue_run_local) *p++ = 'l';
2163 *p = 0;
2164 extra[0] = *queue_name
2165 ? string_sprintf("%sG%s", opt, queue_name) : opt;
2166
2167 #ifdef EXPERIMENTAL_QUEUE_RAMP
2168 if (*queuerun_msgid)
2169 {
2170 extra[extracount++] = queuerun_msgid; /* Trigger only the */
2171 extra[extracount++] = queuerun_msgid; /* one message */
2172 }
2173 #endif
2174
2175 /* If -R or -S were on the original command line, ensure they get
2176 passed on. */
2177
2178 if (deliver_selectstring)
2179 {
2180 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
2181 extra[extracount++] = deliver_selectstring;
2182 }
2183
2184 if (deliver_selectstring_sender)
2185 {
2186 extra[extracount++] = f.deliver_selectstring_sender_regex
2187 ? US"-Sr" : US"-S";
2188 extra[extracount++] = deliver_selectstring_sender;
2189 }
2190
2191 /* Overlay this process with a new execution. */
2192
2193 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
2194 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
2195
2196 /* Control never returns here. */
2197 }
2198
2199 /* No need to re-exec; SIGALRM remains set to the default handler */
2200
2201 #ifdef EXPERIMENTAL_QUEUE_RAMP
2202 if (*queuerun_msgid)
2203 {
2204 f.queue_2stage = FALSE;
2205 queue_run(queuerun_msgid, queuerun_msgid, FALSE);
2206 }
2207 else
2208 #endif
2209 queue_run(NULL, NULL, FALSE);
2210 exim_underbar_exit(EXIT_SUCCESS);
2211 }
2212
2213 if (pid < 0)
2214 {
2215 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
2216 "process failed: %s", strerror(errno));
2217 log_close_all();
2218 }
2219 else
2220 {
2221 for (int i = 0; i < local_queue_run_max; ++i)
2222 if (queue_pid_slots[i] <= 0)
2223 {
2224 queue_pid_slots[i] = pid;
2225 queue_run_count++;
2226 break;
2227 }
2228 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
2229 queue_run_count, queue_run_count == 1 ? "" : "es");
2230 }
2231 }
2232
2233 /* Reset the alarm clock */
2234
2235 sigalrm_seen = FALSE;
2236 #ifdef EXPERIMENTAL_QUEUE_RAMP
2237 if (*queuerun_msgid)
2238 *queuerun_msgid = 0;
2239 else
2240 #endif
2241 ALARM(queue_interval);
2242 }
2243
2244 } /* sigalrm_seen */
2245
2246
2247 /* Sleep till a connection happens if listening, and handle the connection if
2248 that is why we woke up. The FreeBSD operating system requires the use of
2249 select() before accept() because the latter function is not interrupted by
2250 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2251 OS do notice signals in accept() but it does no harm to have the select()
2252 in for all of them - and it won't then be a lurking problem for ports to
2253 new OS. In fact, the later addition of listening on specific interfaces only
2254 requires this way of working anyway. */
2255
2256 if (f.daemon_listen)
2257 {
2258 int lcount, select_errno;
2259 int max_socket = 0;
2260 BOOL select_failed = FALSE;
2261 fd_set select_listen;
2262
2263 FD_ZERO(&select_listen);
2264 if (daemon_notifier_fd >= 0)
2265 FD_SET(daemon_notifier_fd, &select_listen);
2266 for (int sk = 0; sk < listen_socket_count; sk++)
2267 {
2268 FD_SET(listen_sockets[sk], &select_listen);
2269 if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk];
2270 }
2271
2272 DEBUG(D_any) debug_printf("Listening...\n");
2273
2274 /* In rare cases we may have had a SIGCHLD signal in the time between
2275 setting the handler (below) and getting back here. If so, pretend that the
2276 select() was interrupted so that we reap the child. This might still leave
2277 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
2278 only to do the reaping more quickly, it shouldn't result in anything other
2279 than a delay until something else causes a wake-up. */
2280
2281 if (sigchld_seen)
2282 {
2283 lcount = -1;
2284 errno = EINTR;
2285 }
2286 else
2287 lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen,
2288 NULL, NULL, NULL);
2289
2290 if (lcount < 0)
2291 {
2292 select_failed = TRUE;
2293 lcount = 1;
2294 }
2295
2296 /* Clean up any subprocesses that may have terminated. We need to do this
2297 here so that smtp_accept_max_per_host works when a connection to that host
2298 has completed, and we are about to accept a new one. When this code was
2299 later in the sequence, a new connection could be rejected, even though an
2300 old one had just finished. Preserve the errno from any select() failure for
2301 the use of the common select/accept error processing below. */
2302
2303 select_errno = errno;
2304 handle_ending_processes();
2305 errno = select_errno;
2306
2307 #ifndef DISABLE_TLS
2308 /* Create or rotate any required keys */
2309 tls_daemon_init();
2310 #endif
2311
2312 /* Loop for all the sockets that are currently ready to go. If select
2313 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2314 to use the common error code for select/accept below. */
2315
2316 while (lcount-- > 0)
2317 {
2318 int accept_socket = -1;
2319
2320 if (!select_failed)
2321 {
2322 if ( daemon_notifier_fd >= 0
2323 && FD_ISSET(daemon_notifier_fd, &select_listen))
2324 {
2325 FD_CLR(daemon_notifier_fd, &select_listen);
2326 sigalrm_seen = daemon_notification();
2327 break; /* to top of daemon loop */
2328 }
2329 for (int sk = 0; sk < listen_socket_count; sk++)
2330 if (FD_ISSET(listen_sockets[sk], &select_listen))
2331 {
2332 len = sizeof(accepted);
2333 accept_socket = accept(listen_sockets[sk],
2334 (struct sockaddr *)&accepted, &len);
2335 FD_CLR(listen_sockets[sk], &select_listen);
2336 break;
2337 }
2338 }
2339
2340 /* If select or accept has failed and this was not caused by an
2341 interruption, log the incident and try again. With asymmetric TCP/IP
2342 routing errors such as "No route to network" have been seen here. Also
2343 "connection reset by peer" has been seen. These cannot be classed as
2344 disastrous errors, but they could fill up a lot of log. The code in smail
2345 crashes the daemon after 10 successive failures of accept, on the grounds
2346 that some OS fail continuously. Exim originally followed suit, but this
2347 appears to have caused problems. Now it just keeps going, but instead of
2348 logging each error, it batches them up when they are continuous. */
2349
2350 if (accept_socket < 0 && errno != EINTR)
2351 {
2352 if (accept_retry_count == 0)
2353 {
2354 accept_retry_errno = errno;
2355 accept_retry_select_failed = select_failed;
2356 }
2357 else
2358 {
2359 if (errno != accept_retry_errno ||
2360 select_failed != accept_retry_select_failed ||
2361 accept_retry_count >= 50)
2362 {
2363 log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0),
2364 "%d %s() failure%s: %s",
2365 accept_retry_count,
2366 accept_retry_select_failed? "select" : "accept",
2367 (accept_retry_count == 1)? "" : "s",
2368 strerror(accept_retry_errno));
2369 log_close_all();
2370 accept_retry_count = 0;
2371 accept_retry_errno = errno;
2372 accept_retry_select_failed = select_failed;
2373 }
2374 }
2375 accept_retry_count++;
2376 }
2377
2378 else
2379 {
2380 if (accept_retry_count > 0)
2381 {
2382 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2383 accept_retry_count,
2384 accept_retry_select_failed? "select" : "accept",
2385 (accept_retry_count == 1)? "" : "s",
2386 strerror(accept_retry_errno));
2387 log_close_all();
2388 accept_retry_count = 0;
2389 }
2390 }
2391
2392 /* If select/accept succeeded, deal with the connection. */
2393
2394 if (accept_socket >= 0)
2395 {
2396 if (inetd_wait_timeout)
2397 last_connection_time = time(NULL);
2398 handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,
2399 (struct sockaddr *)&accepted);
2400 }
2401 }
2402 }
2403
2404 /* If not listening, then just sleep for the queue interval. If we woke
2405 up early the last time for some other signal, it won't matter because
2406 the alarm signal will wake at the right time. This code originally used
2407 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2408 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2409 select() can be used as an interruptible sleep() on all versions of Unix. */
2410
2411 else
2412 {
2413 struct timeval tv;
2414 tv.tv_sec = queue_interval;
2415 tv.tv_usec = 0;
2416 select(0, NULL, NULL, NULL, &tv);
2417 handle_ending_processes();
2418 }
2419
2420 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2421 for itself, because it isn't doing the waiting itself. */
2422
2423 if (sigchld_seen)
2424 {
2425 sigchld_seen = FALSE;
2426 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
2427 }
2428
2429 /* Handle being woken by SIGHUP. We know at this point that the result
2430 of accept() has been dealt with, so we can re-exec exim safely, first
2431 closing the listening sockets so that they can be reused. Cancel any pending
2432 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2433 that another HUP in quick succession doesn't clobber the new daemon before it
2434 gets going. All log files get closed by the close-on-exec flag; however, if
2435 the exec fails, we need to close the logs. */
2436
2437 if (sighup_seen)
2438 {
2439 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2440 getpid());
2441 for (int sk = 0; sk < listen_socket_count; sk++)
2442 (void)close(listen_sockets[sk]);
2443 ALARM_CLR(0);
2444 signal(SIGHUP, SIG_IGN);
2445 sighup_argv[0] = exim_path;
2446 exim_nullstd();
2447 execv(CS exim_path, (char *const *)sighup_argv);
2448 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2449 getpid(), exim_path, strerror(errno));
2450 log_close_all();
2451 }
2452
2453 } /* End of main loop */
2454
2455 /* Control never reaches here */
2456 }
2457
2458 /* vi: aw ai sw=2
2459 */
2460 /* End of exim_daemon.c */