Move notifier socket to general availability
[exim.git] / src / src / daemon.c
CommitLineData
059ec3d9
PH
1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
f9ba5e22 5/* Copyright (c) University of Cambridge 1995 - 2018 */
059ec3d9
PH
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
16typedef 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
4c04137d 22expressions in assignments except as initializers in declarations). */
059ec3d9 23
f2ed27cf 24static smtp_slot empty_smtp_slot = { .pid = 0, .host_address = NULL };
059ec3d9
PH
25
26
27
28/*************************************************
29* Local static variables *
30*************************************************/
31
cd59ab18
PP
32static SIGNAL_BOOL sigchld_seen;
33static SIGNAL_BOOL sighup_seen;
01446a56 34static SIGNAL_BOOL sigterm_seen;
059ec3d9
PH
35
36static int accept_retry_count = 0;
37static int accept_retry_errno;
38static BOOL accept_retry_select_failed;
39
40static int queue_run_count = 0;
bb6e88ff
PH
41static pid_t *queue_pid_slots = NULL;
42static smtp_slot *smtp_slots = NULL;
059ec3d9
PH
43
44static 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
54Argument: the signal number
55Returns: nothing
56*/
57
58static void
59sighup_handler(int sig)
60{
61sig = sig; /* Keep picky compilers happy */
62sighup_seen = TRUE;
63signal(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
73waiting here. If the signal is re-enabled, there will just be an
74infinite sequence of calls to this handler. The SIGCHLD signal is
75used just as a means of waking up the daemon so that it notices
76terminated subprocesses as soon as possible.
77
78Argument: the signal number
79Returns: nothing
80*/
81
82static void
83main_sigchld_handler(int sig)
84{
85sig = sig; /* Keep picky compilers happy */
7d468ab8 86os_non_restarting_signal(SIGCHLD, SIG_DFL);
059ec3d9 87sigchld_seen = TRUE;
059ec3d9
PH
88}
89
90
01446a56
JH
91/* SIGTERM handler. Try to get the damon pif file removed
92before exiting. */
93
94static void
95main_sigterm_handler(int sig)
96{
97sigterm_seen = TRUE;
98}
99
100
059ec3d9
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101
102
103/*************************************************
104* Unexpected errors in SMTP calls *
105*************************************************/
106
107/* This function just saves a bit of repetitious coding.
108
109Arguments:
110 log_msg Text of message to be logged
111 smtp_msg Text of SMTP error message
112 was_errno The failing errno
113
114Returns: nothing
115*/
116
117static void
118never_error(uschar *log_msg, uschar *smtp_msg, int was_errno)
119{
52f12a7c
JH
120uschar *emsg = was_errno <= 0
121 ? US"" : string_sprintf(": %s", strerror(was_errno));
059ec3d9 122log_write(0, LOG_MAIN|LOG_PANIC, "%s%s", log_msg, emsg);
52f12a7c 123if (smtp_out) smtp_printf("421 %s\r\n", FALSE, smtp_msg);
059ec3d9
PH
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.
134If there are too many, give an error message and close down. Otherwise
135spin off a sub-process to handle the call. The list of listening sockets
136is required so that they can be closed in the sub-process. Take care not to
137leak store in this process - reset the stacking pool at the end.
138
139Arguments:
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
145Returns: nothing
146*/
147
148static void
149handle_smtp_call(int *listen_sockets, int listen_socket_count,
150 int accept_socket, struct sockaddr *accepted)
151{
152pid_t pid;
153union sockaddr_46 interface_sockaddr;
36a3b041 154EXIM_SOCKLEN_T ifsize = sizeof(interface_sockaddr);
059ec3d9
PH
155int dup_accept_socket = -1;
156int max_for_this_host = 0;
6c6d6e48 157int save_log_selector = *log_selector;
b2bcdd35 158gstring * whofrom;
059ec3d9 159
f3ebb786 160rmark reset_point = store_mark();
059ec3d9
PH
161
162/* Make the address available in ASCII representation, and also fish out
163the remote port. */
164
165sender_host_address = host_ntoa(-1, accepted, NULL, &sender_host_port);
166DEBUG(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
170input stream. These operations fail only the exceptional circumstances. Note
171that never_error() won't use smtp_out if it is NULL. */
172
f5d25c2b 173if (!(smtp_out = fdopen(accept_socket, "wb")))
059ec3d9
PH
174 {
175 never_error(US"daemon: fdopen() for smtp_out failed", US"", errno);
176 goto ERROR_RETURN;
177 }
178
f5d25c2b 179if ((dup_accept_socket = dup(accept_socket)) < 0)
059ec3d9
PH
180 {
181 never_error(US"daemon: couldn't dup socket descriptor",
182 US"Connection setup failed", errno);
183 goto ERROR_RETURN;
184 }
185
f5d25c2b 186if (!(smtp_in = fdopen(dup_accept_socket, "rb")))
059ec3d9
PH
187 {
188 never_error(US"daemon: fdopen() for smtp_in failed",
189 US"Connection setup failed", errno);
190 goto ERROR_RETURN;
191 }
192
520de300
PH
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. */
059ec3d9
PH
195
196if (getsockname(accept_socket, (struct sockaddr *)(&interface_sockaddr),
197 &ifsize) < 0)
198 {
520de300
PH
199 log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC),
200 "getsockname() failed: %s", strerror(errno));
925ac8e4 201 smtp_printf("421 Local problem: getsockname() failed; please try again later\r\n", FALSE);
059ec3d9
PH
202 goto ERROR_RETURN;
203 }
204
205interface_address = host_ntoa(-1, &interface_sockaddr, NULL, &interface_port);
206DEBUG(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
210the local interface data. This is for logging; at the end of this function the
211memory is reclaimed. */
212
b2bcdd35 213whofrom = string_append(NULL, 3, "[", sender_host_address, "]");
059ec3d9 214
6c6d6e48 215if (LOGGING(incoming_port))
52f12a7c 216 whofrom = string_fmt_append(whofrom, ":%d", sender_host_port);
059ec3d9 217
6c6d6e48 218if (LOGGING(incoming_interface))
52f12a7c
JH
219 whofrom = string_fmt_append(whofrom, " I=[%s]:%d",
220 interface_address, interface_port);
059ec3d9 221
acec9514 222(void) string_from_gstring(whofrom); /* Terminate the newly-built string */
059ec3d9
PH
223
224/* Check maximum number of connections. We do not check for reserved
225connections or unacceptable hosts here. That is done in the subprocess because
226it might take some time. */
227
228if (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; "
925ac8e4 233 "please try again later.\r\n", FALSE);
059ec3d9
PH
234 log_write(L_connection_reject,
235 LOG_MAIN, "Connection from %s refused: too many connections",
acec9514 236 whofrom->s);
059ec3d9
PH
237 goto ERROR_RETURN;
238 }
239
240/* If a load limit above which only reserved hosts are acceptable is defined,
241get the load average here, and if there are in fact no reserved hosts, do
242the test right away (saves a fork). If there are hosts, do the check in the
243subprocess because it might take time. */
244
245if (smtp_load_reserve >= 0)
246 {
8669f003 247 load_average = OS_GETLOADAVG();
059ec3d9
PH
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);
925ac8e4 252 smtp_printf("421 Too much load; please try again later.\r\n", FALSE);
059ec3d9
PH
253 log_write(L_connection_reject,
254 LOG_MAIN, "Connection from %s refused: load average = %.2f",
acec9514 255 whofrom->s, (double)load_average/1000.0);
059ec3d9
PH
256 goto ERROR_RETURN;
257 }
258 }
259
260/* Check that one specific host (strictly, IP address) is not hogging
261resources. This is done here to prevent a denial of service attack by someone
262forcing you to fork lots of times before denying service. The value of
263smtp_accept_max_per_host is a string which is expanded. This makes it possible
264to provide host-specific limits according to $sender_host address, but because
265this is in the daemon mainline, only fast expansions (such as inline address
266checks) should be used. The documentation is full of warnings. */
267
268if (smtp_accept_max_per_host != NULL)
269 {
270 uschar *expanded = expand_string(smtp_accept_max_per_host);
271 if (expanded == NULL)
272 {
8768d548 273 if (!f.expand_string_forcedfail)
059ec3d9 274 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
acec9514 275 "failed for %s: %s", whofrom->s, expand_string_message);
059ec3d9
PH
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 "
acec9514 285 "for %s contains non-digit: %s", whofrom->s, expanded);
059ec3d9
PH
286 }
287 }
288
289/* If we have fewer connections than max_for_this_host, we can skip the tedious
290per host_address checks. Note that at this stage smtp_accept_count contains the
291count of *other* connections, not including this one. */
292
293if ((max_for_this_host > 0) &&
294 (smtp_accept_count >= max_for_this_host))
295 {
059ec3d9
PH
296 int host_accept_count = 0;
297 int other_host_count = 0; /* keep a count of non matches to optimise */
298
d7978c0f 299 for (int i = 0; i < smtp_accept_max; ++i)
8cfd0f7b 300 if (smtp_slots[i].host_address)
059ec3d9
PH
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 }
059ec3d9
PH
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 "
925ac8e4 322 "from this IP address; please try again later.\r\n", FALSE);
059ec3d9
PH
323 log_write(L_connection_reject,
324 LOG_MAIN, "Connection from %s refused: too many connections "
acec9514 325 "from that IP address", whofrom->s);
059ec3d9
PH
326 goto ERROR_RETURN;
327 }
328 }
329
330/* OK, the connection count checks have been passed. Before we can fork the
331accepting process, we must first log the connection if requested. This logging
332used to happen in the subprocess, but doing that means that the value of
333smtp_accept_count can be out of step by the time it is logged. So we have to do
334the logging here and accept the performance cost. Note that smtp_accept_count
335hasn't yet been incremented to take account of this connection.
336
337In order to minimize the cost (because this is going to happen for every
338connection), do a preliminary selector test here. This saves ploughing through
339the generalized logging code each time when the selector is false. If the
340selector is set, check whether the host is on the list for logging. If not,
341arrange to unset the selector in the subprocess. */
342
6c6d6e48 343if (LOGGING(smtp_connection))
059ec3d9
PH
344 {
345 uschar *list = hosts_connection_nolog;
ce325893 346 memset(sender_host_cache, 0, sizeof(sender_host_cache));
059ec3d9 347 if (list != NULL && verify_check_host(&list) == OK)
6c6d6e48 348 save_log_selector &= ~L_smtp_connection;
059ec3d9
PH
349 else
350 log_write(L_smtp_connection, LOG_MAIN, "SMTP connection from %s "
acec9514 351 "(TCP/IP connection count = %d)", whofrom->s, smtp_accept_count + 1);
059ec3d9
PH
352 }
353
354/* Now we can fork the accepting process; do a lookup tidy, just in case any
355expansion above did a lookup. */
356
357search_tidyup();
358pid = fork();
359
360/* Handle the child process */
361
362if (pid == 0)
363 {
364 int i;
365 int queue_only_reason = 0;
366 int old_pool = store_pool;
8e669ac1 367 int save_debug_selector = debug_selector;
059ec3d9 368 BOOL local_queue_only;
8669f003 369 BOOL session_local_queue_only;
059ec3d9
PH
370 #ifdef SA_NOCLDWAIT
371 struct sigaction act;
372 #endif
373
b01dd148
PH
374 smtp_accept_count++; /* So that it includes this process */
375
059ec3d9
PH
376 /* May have been modified for the subprocess */
377
6c6d6e48 378 *log_selector = save_log_selector;
059ec3d9
PH
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
817d9f57 388 if (host_is_tls_on_connect_port(interface_port)) tls_in.on_connect = TRUE;
059ec3d9
PH
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;
ad7fc6eb 395 if (raw_active_hostname)
059ec3d9 396 {
ad7fc6eb
JH
397 uschar * nah = expand_string(raw_active_hostname);
398 if (!nah)
059ec3d9 399 {
8768d548 400 if (!f.expand_string_forcedfail)
059ec3d9
PH
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; "
925ac8e4 406 "please try again later.\r\n", FALSE);
059ec3d9
PH
407 mac_smtp_fflush();
408 search_tidyup();
f3ebb786 409 exim_underbar_exit(EXIT_FAILURE);
059ec3d9
PH
410 }
411 }
ad7fc6eb 412 else if (*nah) smtp_active_hostname = nah;
059ec3d9
PH
413 }
414
415 /* Initialize the queueing flags */
416
417 queue_check_only();
8669f003 418 session_local_queue_only = queue_only;
059ec3d9
PH
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
f1e894f3 427 for (i = 0; i < listen_socket_count; i++) (void)close(listen_sockets[i]);
059ec3d9 428
fa32850b
DW
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
059ec3d9
PH
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
01446a56 444 signal(SIGTERM, SIG_DFL);
059ec3d9
PH
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
8e669ac1
PH
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
3d235903 453 incoming connection is output. */
8e669ac1 454
8768d548 455 if (f.debug_daemon) debug_selector = 0;
059ec3d9
PH
456 verify_get_ident(IDENT_PORT);
457 host_build_sender_fullhost();
8e669ac1 458 debug_selector = save_debug_selector;
059ec3d9
PH
459
460 DEBUG(D_any)
461 debug_printf("Process %d is handling incoming connection from %s\n",
462 (int)getpid(), sender_fullhost);
463
3d235903
PH
464 /* Now disable debugging permanently if it's required only for the daemon
465 process. */
466
8768d548 467 if (f.debug_daemon) debug_selector = 0;
3d235903 468
059ec3d9 469 /* If there are too many child processes for immediate delivery,
8669f003 470 set the session_local_queue_only flag, which is initialized from the
059ec3d9 471 configured value and may therefore already be TRUE. Leave logging
8669f003
PH
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. */
059ec3d9 475
b01dd148 476 if (smtp_accept_queue > 0 && smtp_accept_count > smtp_accept_queue)
059ec3d9 477 {
8669f003 478 session_local_queue_only = TRUE;
059ec3d9
PH
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
24796b8d
PH
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. */
059ec3d9
PH
491
492 if (!smtp_start_session())
493 {
494 mac_smtp_fflush();
495 search_tidyup();
f3ebb786 496 exim_underbar_exit(EXIT_SUCCESS);
059ec3d9
PH
497 }
498
499 for (;;)
500 {
501 int rc;
502 message_id[0] = 0; /* Clear out any previous message_id */
f3ebb786 503 reset_point = store_mark(); /* Save current store high water point */
059ec3d9
PH
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 {
57cc2785 521 cancel_cutthrough_connection(TRUE, US"receive dropped");
059ec3d9 522 mac_smtp_fflush();
b4ed4da0 523 smtp_log_no_mail(); /* Log no mail if configured */
f3ebb786 524 exim_underbar_exit(EXIT_SUCCESS);
059ec3d9
PH
525 }
526 if (message_id[0] == 0) continue; /* No message was accepted */
527 }
528 else
529 {
ad7fc6eb
JH
530 if (smtp_out)
531 {
d7978c0f 532 int fd = fileno(smtp_in);
ad7fc6eb
JH
533 uschar buf[128];
534
535 mac_smtp_fflush();
536 /* drain socket, for clean TCP FINs */
5ddc9771 537 if (fcntl(fd, F_SETFL, O_NONBLOCK) == 0)
d7978c0f 538 for(int i = 16; read(fd, buf, sizeof(buf)) > 0 && i > 0; ) i--;
ad7fc6eb 539 }
57cc2785 540 cancel_cutthrough_connection(TRUE, US"message setup dropped");
059ec3d9 541 search_tidyup();
b4ed4da0 542 smtp_log_no_mail(); /* Log no mail if configured */
60d10ce7
JH
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");
f3ebb786 547 exim_underbar_exit(rc ? EXIT_FAILURE : EXIT_SUCCESS);
059ec3d9
PH
548 }
549
550 /* Show the recipients when debugging */
551
552 DEBUG(D_receive)
553 {
2c0f3ea1 554 if (sender_address)
059ec3d9 555 debug_printf("Sender: %s\n", sender_address);
2c0f3ea1 556 if (recipients_list)
059ec3d9
PH
557 {
558 debug_printf("Recipients:\n");
d7978c0f 559 for (int i = 0; i < recipients_count; i++)
059ec3d9
PH
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
e04bfa34
JH
576 {
577 int r = receive_messagecount;
8768d548 578 BOOL q = f.queue_only_policy;
e04bfa34 579 smtp_reset(reset_point);
f3ebb786 580 reset_point = NULL;
8768d548 581 f.queue_only_policy = q;
e04bfa34
JH
582 receive_messagecount = r;
583 }
059ec3d9
PH
584
585 /* If queue_only is set or if there are too many incoming connections in
8669f003
PH
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)
059ec3d9 593 {
8669f003
PH
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
f5d25c2b
JH
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 )
8669f003 613 {
f5d25c2b
JH
614 queue_only_reason = 3;
615 if (queue_only_load_latch) session_local_queue_only = TRUE;
059ec3d9
PH
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 {
f5d25c2b 623 case 1: log_write(L_delay_delivery,
059ec3d9
PH
624 LOG_MAIN, "no immediate delivery: too many connections "
625 "(%d, max %d)", smtp_accept_count, smtp_accept_queue);
f5d25c2b 626 break;
059ec3d9 627
f5d25c2b 628 case 2: log_write(L_delay_delivery,
059ec3d9
PH
629 LOG_MAIN, "no immediate delivery: more than %d messages "
630 "received in one connection", smtp_accept_queue_per_connection);
f5d25c2b 631 break;
059ec3d9 632
f5d25c2b 633 case 3: log_write(L_delay_delivery,
059ec3d9
PH
634 LOG_MAIN, "no immediate delivery: load average %.2f",
635 (double)load_average/1000.0);
f5d25c2b 636 break;
059ec3d9
PH
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
9438970c
JH
643 else if ( (!f.queue_only_policy || f.queue_smtp)
644 && !f.deliver_freeze)
059ec3d9
PH
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 {
f1e894f3
PH
656 (void)fclose(smtp_in);
657 (void)fclose(smtp_out);
059ec3d9
PH
658
659 /* Don't ever molest the parent's SSL connection, but do clean up
660 the data structures if necessary. */
661
01603eec 662#ifndef DISABLE_TLS
74f1a423 663 tls_close(NULL, TLS_NO_SHUTDOWN);
57cc2785 664#endif
059ec3d9
PH
665
666 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
667
668 signal(SIGHUP, SIG_DFL);
669 signal(SIGCHLD, SIG_DFL);
01446a56 670 signal(SIGTERM, SIG_DFL);
059ec3d9
PH
671
672 if (geteuid() != root_uid && !deliver_drop_privilege)
673 {
674 signal(SIGALRM, SIG_DFL);
57cc2785 675 delivery_re_exec(CEE_EXEC_PANIC);
059ec3d9
PH
676 /* Control does not return here. */
677 }
678
679 /* No need to re-exec; SIGALRM remains set to the default handler */
680
57cc2785 681 (void) deliver_message(message_id, FALSE, FALSE);
059ec3d9 682 search_tidyup();
f3ebb786 683 exim_underbar_exit(EXIT_SUCCESS);
059ec3d9
PH
684 }
685
686 if (dpid > 0)
687 {
57cc2785 688 release_cutthrough_connection(US"passed for delivery");
059ec3d9
PH
689 DEBUG(D_any) debug_printf("forked delivery process %d\n", (int)dpid);
690 }
691 else
57cc2785
JH
692 {
693 cancel_cutthrough_connection(TRUE, US"delivery fork failed");
059ec3d9
PH
694 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: delivery process fork "
695 "failed: %s", strerror(errno));
57cc2785 696 }
059ec3d9
PH
697 }
698 }
699 }
700
701
702/* Carrying on in the parent daemon process... Can't do much if the fork
703failed. Otherwise, keep count of the number of accepting processes and
704remember the pid for ticking off when the child completes. */
705
706if (pid < 0)
059ec3d9 707 never_error(US"daemon: accept process fork failed", US"Fork failed", errno);
059ec3d9
PH
708else
709 {
d7978c0f 710 for (int i = 0; i < smtp_accept_max; ++i)
059ec3d9
PH
711 if (smtp_slots[i].pid <= 0)
712 {
713 smtp_slots[i].pid = pid;
f3ebb786
JH
714 /* Connection closes come asyncronously, so we cannot stack this store */
715 if (smtp_accept_max_per_host)
059ec3d9
PH
716 smtp_slots[i].host_address = string_copy_malloc(sender_host_address);
717 smtp_accept_count++;
718 break;
719 }
059ec3d9 720 DEBUG(D_any) debug_printf("%d SMTP accept process%s running\n",
f3ebb786 721 smtp_accept_count, smtp_accept_count == 1 ? "" : "es");
059ec3d9
PH
722 }
723
724/* Get here via goto in error cases */
725
726ERROR_RETURN:
727
728/* Close the streams associated with the socket which will also close the
729socket fds in this process. We can't do anything if fclose() fails, but
730logging brings it to someone's attention. However, "connection reset by peer"
1f872c80
PH
731isn't really a problem, so skip that one. On Solaris, a dropped connection can
732manifest itself as a broken pipe, so drop that one too. If the streams don't
733exist, something went wrong while setting things up. Make sure the socket
734descriptors are closed, in order to drop the connection. */
059ec3d9 735
f5d25c2b 736if (smtp_out)
059ec3d9 737 {
1f872c80 738 if (fclose(smtp_out) != 0 && errno != ECONNRESET && errno != EPIPE)
059ec3d9
PH
739 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_out) failed: %s",
740 strerror(errno));
741 smtp_out = NULL;
742 }
f1e894f3 743else (void)close(accept_socket);
059ec3d9 744
f5d25c2b 745if (smtp_in)
059ec3d9 746 {
1f872c80 747 if (fclose(smtp_in) != 0 && errno != ECONNRESET && errno != EPIPE)
059ec3d9
PH
748 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_in) failed: %s",
749 strerror(errno));
750 smtp_in = NULL;
751 }
f1e894f3 752else (void)close(dup_accept_socket);
059ec3d9
PH
753
754/* Release any store used in this process, including the store used for holding
755the incoming host address and an expanded active_hostname. */
756
c8899c20 757log_close_all();
90341c71
JH
758interface_address =
759sender_host_address = NULL;
059ec3d9
PH
760store_reset(reset_point);
761sender_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
772ports. It tests for special cases of wildcard listening, when IPv4 and IPv6
773sockets may interact in different ways in different operating systems. It is
774passed an error number, the list of listening addresses, and the current
775address. Two checks are available: for a previous wildcard IPv6 address, or for
776a following wildcard IPv4 address, in both cases on the same port.
777
778In practice, pairs of wildcard addresses should be adjacent in the address list
779because they are sorted that way below.
780
781Arguments:
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
788Returns: TRUE or FALSE
789*/
790
791static BOOL
792check_special_case(int eno, ip_address_item *addresses, ip_address_item *ipa,
793 BOOL back)
794{
795ip_address_item *ipa2;
796
797/* For the "back" case, if the failure was "address in use" for a wildcard IPv4
798address, seek a previous IPv6 wildcard address on the same port. As it is
799previous, it must have been successfully bound and be listening. Flag it as a
800"6 including 4" listener. */
801
802if (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,
816we seek a following wildcard IPv4 address on the same port. */
817
818else
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
825return FALSE;
826}
827
828
829
830
bb6e88ff
PH
831/*************************************************
832* Handle terminating subprocesses *
833*************************************************/
834
835/* Handle the termination of child processes. Theoretically, this need be done
836only when sigchld_seen is TRUE, but rumour has it that some systems lose
837SIGCHLD signals at busy times, so to be on the safe side, this function is
838called each time round. It shouldn't be too expensive.
839
840Arguments: none
841Returns: nothing
842*/
843
844static void
845handle_ending_processes(void)
846{
847int status;
848pid_t pid;
849
850while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
851 {
7be682ca
PP
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 }
bb6e88ff 863
8e669ac1 864 /* If it's a listening daemon for which we are keeping track of individual
bb6e88ff
PH
865 subprocesses, deal with an accepting process that has terminated. */
866
8cfd0f7b 867 if (smtp_slots)
bb6e88ff 868 {
f3ebb786 869 int i;
bb6e88ff 870 for (i = 0; i < smtp_accept_max; i++)
bb6e88ff
PH
871 if (smtp_slots[i].pid == pid)
872 {
8cfd0f7b 873 if (smtp_slots[i].host_address)
bb6e88ff
PH
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 }
bb6e88ff
PH
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
0cd5fd23 887 if (queue_pid_slots)
bb6e88ff 888 {
4dc2379a 889 int max = atoi(CS expand_string(queue_run_max));
f3ebb786 890 for (int i = 0; i < max; i++)
bb6e88ff
PH
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 }
bb6e88ff
PH
899 }
900 }
901}
902
059ec3d9
PH
903
904
01446a56
JH
905static void
906set_pid_file_path(void)
907{
908if (override_pid_file_path)
909 pid_file_path = override_pid_file_path;
910
911if (!*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,
917as a direct child of the daemon. Does not return. */
918
919void
920delete_pid_file(void)
921{
922uschar * daemon_pid = string_sprintf("%d\n", (int)getppid());
923FILE * f;
924
925set_pid_file_path();
926if ((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 }
941else
942 DEBUG(D_any)
943 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
944 pid_file_path));
945exim_exit(EXIT_SUCCESS, US"pid file remover");
946}
947
948
949/* Called by the daemon; exec a child to get the pid file deleted
950since we may require privs for the containing directory */
951
952static void
953daemon_die(void)
954{
955int pid;
956
957if (f.running_in_test_harness || write_pid)
958 {
959 if ((pid = fork()) == 0)
960 {
961 if (override_pid_file_path)
962 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 3,
963 "-oP", override_pid_file_path, "-oPX");
964 else
965 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 1, "-oPX");
966
967 /* Control never returns here. */
968 }
969 if (pid > 0)
970 child_close(pid, 1);
971 }
972exim_exit(EXIT_SUCCESS, US"daemon");
973}
974
975
ff966302
JH
976/*************************************************
977* Listener socket for local work prompts *
978*************************************************/
979
980static void
981daemon_notifier_socket(void)
982{
983int fd;
984const uschar * where;
985struct sockaddr_un sun = {.sun_family = AF_UNIX};
986
987DEBUG(D_any) debug_printf("creating notifier socket\n");
988
989where = US"socket";
990#ifdef SOCK_CLOEXEC
991if ((fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0)
992 goto bad;
993#else
994if ((fd = socket(AF_UNIX, SOCK_DGRAM, 0))) < 0)
995 goto bad;
996(void)fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
997#endif
998
999snprintf(sun.sun_path, sizeof(sun.sun_path), "%s/%s",
1000 spool_directory, NOTIFIER_SOCKET_NAME);
1001where = US"bind";
1002if (bind(fd, (const struct sockaddr *)&sun, sizeof(sun)) < 0)
1003 goto bad;
1004
1005where = US"SO_PASSCRED";
1006if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0)
1007 goto bad;
1008
1009/* debug_printf("%s: fd %d\n", __FUNCTION__, fd); */
1010daemon_notifier_fd = fd;
1011return;
1012
1013bad:
1014 log_write(0, LOG_MAIN|LOG_PANIC, "%s: %s: %s",
1015 __FUNCTION__, where, strerror(errno));
1016}
1017
1018
1019static uschar queuerun_msgid[MESSAGE_ID_LENGTH+1];
1020
1021/* Return TRUE if a sigalrm should be emulated */
1022static BOOL
1023daemon_notification(void)
1024{
1025uschar buf[256], cbuf[256];
1026struct iovec iov = {.iov_base = buf, .iov_len = sizeof(buf)-1};
1027struct msghdr msg = { .msg_name = NULL,
1028 .msg_namelen = 0,
1029 .msg_iov = &iov,
1030 .msg_iovlen = 1,
1031 .msg_control = cbuf,
1032 .msg_controllen = sizeof(cbuf)
1033 };
1034ssize_t sz;
1035struct cmsghdr * cp;
1036
1037buf[sizeof(buf)-1] = 0;
1038if ((sz = recvmsg(daemon_notifier_fd, &msg, 0)) <= 0) return FALSE;
1039if (sz >= sizeof(buf)) return FALSE;
1040
1041for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg);
1042 cp;
1043 cp = CMSG_NXTHDR(&msg, cp))
1044 if (cp->cmsg_level == SOL_SOCKET && cp->cmsg_type == SCM_CREDENTIALS)
1045 {
1046 struct ucred * cr = (struct ucred *) CMSG_DATA(cp);
1047 if (cr->uid && cr->uid != exim_uid)
1048 {
1049 DEBUG(D_queue_run) debug_printf("%s: sender creds pid %d uid %d gid %d\n",
1050 __FUNCTION__, (int)cr->pid, (int)cr->uid, (int)cr->gid);
1051 return FALSE;
1052 }
1053 break;
1054 }
1055
1056buf[sz] = 0;
1057switch (buf[0])
1058 {
4c2efd7a 1059#ifdef EXPERIMENTAL_QUEUE_RAMP
ff966302
JH
1060 case NOTIFY_MSG_QRUN:
1061 /* this should be a message_id */
1062 DEBUG(D_queue_run)
1063 debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1);
1064 memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1);
1065 return TRUE;
4c2efd7a 1066#endif /*EXPERIMENTAL_QUEUE_RAMP*/
ff966302
JH
1067 }
1068return FALSE;
1069}
ff966302
JH
1070
1071
059ec3d9
PH
1072/*************************************************
1073* Exim Daemon Mainline *
1074*************************************************/
1075
1076/* The daemon can do two jobs, either of which is optional:
1077
1078(1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1079each one. This is requested by the -bd option, with -oX specifying the SMTP
1080port on which to listen (for testing).
1081
1082(2) Spawns a queue-running process every so often. This is controlled by the
1083-q option with a an interval time. (If no time is given, a single queue run
1084is done from the main function, and control doesn't get here.)
1085
1086Root privilege is required in order to attach to port 25. Some systems require
1087it when calling socket() rather than bind(). To cope with all cases, we run as
1088root for both socket() and bind(). Some systems also require root in order to
1089write to the pid file directory. This function must therefore be called as root
1090if it is to work properly in all circumstances. Once the socket is bound and
1091the pid file written, root privilege is given up if there is an exim uid.
1092
1093There are no arguments to this function, and it never returns. */
1094
1095void
1096daemon_go(void)
1097{
ebeaf996 1098struct passwd *pw;
059ec3d9
PH
1099int *listen_sockets = NULL;
1100int listen_socket_count = 0;
1101ip_address_item *addresses = NULL;
9ee44efb 1102time_t last_connection_time = (time_t)0;
4dc2379a 1103int local_queue_run_max = atoi(CS expand_string(queue_run_max));
059ec3d9
PH
1104
1105/* If any debugging options are set, turn on the D_pid bit so that all
1106debugging lines get the pid added. */
1107
1108DEBUG(D_any|D_v) debug_selector |= D_pid;
1109
8768d548 1110if (f.inetd_wait_mode)
9ee44efb 1111 {
9ee44efb 1112 listen_socket_count = 1;
f3ebb786 1113 listen_sockets = store_get(sizeof(int), FALSE);
9ee44efb
PP
1114 (void) close(3);
1115 if (dup2(0, 3) == -1)
9ee44efb
PP
1116 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1117 "failed to dup inetd socket safely away: %s", strerror(errno));
d4ff61d1 1118
9ee44efb
PP
1119 listen_sockets[0] = 3;
1120 (void) close(0);
1121 (void) close(1);
1122 (void) close(2);
1123 exim_nullstd();
1124
1125 if (debug_file == stderr)
1126 {
1127 /* need a call to log_write before call to open debug_file, so that
1128 log.c:file_path has been initialised. This is unfortunate. */
1129 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1130
1131 fclose(debug_file);
1132 debug_file = NULL;
1133 exim_nullstd(); /* re-open fd2 after we just closed it again */
1134 debug_logging_activate(US"-wait", NULL);
1135 }
1136
1137 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1138
1139 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1140 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1141
d4ff61d1
JH
1142 if (tcp_nodelay)
1143 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1144 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1145 strerror(errno));
9ee44efb
PP
1146 }
1147
1148
8768d548 1149if (f.inetd_wait_mode || f.daemon_listen)
9ee44efb
PP
1150 {
1151 /* If any option requiring a load average to be available during the
1152 reception of a message is set, call os_getloadavg() while we are root
1153 for those OS for which this is necessary the first time it is called (in
1154 order to perform an "open" on the kernel memory file). */
1155
1156 #ifdef LOAD_AVG_NEEDS_ROOT
1157 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1158 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1159 (void)os_getloadavg();
1160 #endif
1161 }
1162
059ec3d9
PH
1163
1164/* Do the preparation for setting up a listener on one or more interfaces, and
1165possible on various ports. This is controlled by the combination of
1166local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1167(which is a list of default ports to use for those items in local_interfaces
1168that do not specify a port). The -oX command line option can be used to
1169override one or both of these options.
1170
1171If local_interfaces is not set, the default is to listen on all interfaces.
1172When it is set, it can include "all IPvx interfaces" as an item. This is useful
1173when different ports are in use.
1174
1175It turns out that listening on all interfaces is messy in an IPv6 world,
1176because several different implementation approaches have been taken. This code
1177is now supposed to work with all of them. The point of difference is whether an
1178IPv6 socket that is listening on all interfaces will receive incoming IPv4
1179calls or not. We also have to cope with the case when IPv6 libraries exist, but
1180there is no IPv6 support in the kernel.
1181
1182. On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1183 addresses. However, if an IPv4 socket is also listening on all interfaces,
1184 calls are directed to the appropriate socket.
1185
1186. On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1187 give them as mapped addresses, but an attempt also to listen on an IPv4
1188 socket on all interfaces causes an error.
1189
1190. On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1191 two sockets if you want to accept both kinds of call.
1192
1193. FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1194 can be turned off, to make it behave like the versions of Linux described
1195 above.
1196
1197. I heard a report that the USAGI IPv6 stack for Linux has implemented
1198 IPV6_V6ONLY.
1199
1200So, what we do when IPv6 is supported is as follows:
1201
1202 (1) After it is set up, the list of interfaces is scanned for wildcard
1203 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1204 port, the list is re-arranged so that they are together, with the IPv6
1205 wildcard first.
1206
1207 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1208 carry on if an IPv4 wildcard socket for the same port follows later in the
1209 list. This allows Exim to carry on in the case when the kernel has no IPv6
1210 support.
1211
1212 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1213 option is defined. However, if setting fails, carry on regardless (but log
1214 the incident).
1215
1216 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1217 error.
1218
1219 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1220 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1221 port (which must have succeeded or we wouldn't have got this far), we
1222 assume we are in the situation where just a single socket is permitted,
1223 and ignore the error.
1224
1225Phew!
1226
1227The preparation code decodes options and sets up the relevant data. We do this
1228first, so that we can return non-zero if there are any syntax errors, and also
1229write to stderr. */
1230
8768d548 1231if (f.daemon_listen && !f.inetd_wait_mode)
059ec3d9
PH
1232 {
1233 int *default_smtp_port;
1234 int sep;
1235 int pct = 0;
1236 uschar *s;
55414b25 1237 const uschar * list;
059ec3d9
PH
1238 uschar *local_iface_source = US"local_interfaces";
1239 ip_address_item *ipa;
1240 ip_address_item **pipa;
1241
059ec3d9
PH
1242 /* If -oX was used, disable the writing of a pid file unless -oP was
1243 explicitly used to force it. Then scan the string given to -oX. Any items
1244 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1245 Any other items are used to override local_interfaces. */
1246
acec9514 1247 if (override_local_interfaces)
059ec3d9 1248 {
acec9514
JH
1249 gstring * new_smtp_port = NULL;
1250 gstring * new_local_interfaces = NULL;
059ec3d9 1251
01446a56 1252 if (!override_pid_file_path) write_pid = FALSE;
059ec3d9
PH
1253
1254 list = override_local_interfaces;
1255 sep = 0;
55414b25 1256 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
059ec3d9
PH
1257 {
1258 uschar joinstr[4];
01446a56 1259 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
059ec3d9 1260
acec9514 1261 if (!*gp)
059ec3d9
PH
1262 {
1263 joinstr[0] = sep;
1264 joinstr[1] = ' ';
acec9514 1265 *gp = string_catn(*gp, US"<", 1);
059ec3d9
PH
1266 }
1267
acec9514
JH
1268 *gp = string_catn(*gp, joinstr, 2);
1269 *gp = string_cat (*gp, s);
059ec3d9
PH
1270 }
1271
acec9514 1272 if (new_smtp_port)
059ec3d9 1273 {
acec9514 1274 daemon_smtp_port = string_from_gstring(new_smtp_port);
059ec3d9
PH
1275 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1276 daemon_smtp_port);
1277 }
1278
acec9514 1279 if (new_local_interfaces)
059ec3d9 1280 {
acec9514 1281 local_interfaces = string_from_gstring(new_local_interfaces);
059ec3d9
PH
1282 local_iface_source = US"-oX data";
1283 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1284 local_interfaces);
1285 }
1286 }
1287
1288 /* Create a list of default SMTP ports, to be used if local_interfaces
4c04137d 1289 contains entries without explicit ports. First count the number of ports, then
059ec3d9
PH
1290 build a translated list in a vector. */
1291
1292 list = daemon_smtp_port;
1293 sep = 0;
55414b25 1294 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
059ec3d9 1295 pct++;
f3ebb786 1296 default_smtp_port = store_get((pct+1) * sizeof(int), FALSE);
059ec3d9
PH
1297 list = daemon_smtp_port;
1298 sep = 0;
1299 for (pct = 0;
55414b25 1300 (s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size));
059ec3d9
PH
1301 pct++)
1302 {
1303 if (isdigit(*s))
1304 {
1305 uschar *end;
1306 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1307 if (end != s + Ustrlen(s))
1308 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1309 }
1310 else
1311 {
1312 struct servent *smtp_service = getservbyname(CS s, "tcp");
071c51f7 1313 if (!smtp_service)
059ec3d9
PH
1314 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1315 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1316 }
1317 }
1318 default_smtp_port[pct] = 0;
1319
071c51f7
JH
1320 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1321
1322 list = tls_in.on_connect_ports;
1323 sep = 0;
1324 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1325 if (!isdigit(*s))
1326 {
acec9514 1327 gstring * g = NULL;
4226691b 1328
071c51f7
JH
1329 list = tls_in.on_connect_ports;
1330 tls_in.on_connect_ports = NULL;
1331 sep = 0;
1332 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1333 {
1334 if (!isdigit(*s))
1335 {
4226691b 1336 struct servent * smtp_service = getservbyname(CS s, "tcp");
071c51f7
JH
1337 if (!smtp_service)
1338 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
4226691b 1339 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
071c51f7 1340 }
acec9514 1341 g = string_append_listele(g, ':', s);
071c51f7 1342 }
acec9514
JH
1343 if (g)
1344 tls_in.on_connect_ports = g->s;
071c51f7
JH
1345 break;
1346 }
1347
059ec3d9
PH
1348 /* Create the list of local interfaces, possibly with ports included. This
1349 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1350 values are converted below. */
1351
1352 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1353
1354 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1355 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1356 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1357 anyway, but we need to know which are the wildcard addresses, and the shorter
1358 strings are neater.
1359
1360 In the same scan, fill in missing port numbers from the default list. When
1361 there is more than one item in the list, extra items are created. */
1362
b891534f 1363 for (ipa = addresses; ipa; ipa = ipa->next)
059ec3d9 1364 {
b891534f
JH
1365 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1366 ipa->address[0] = 0;
059ec3d9
PH
1367 else if (Ustrcmp(ipa->address, "::0") == 0)
1368 {
1369 ipa->address[0] = ':';
1370 ipa->address[1] = 0;
1371 }
1372
1373 if (ipa->port > 0) continue;
1374
1375 if (daemon_smtp_port[0] <= 0)
1376 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1377 "%s and daemon_smtp_port is unset; cannot start daemon",
b891534f
JH
1378 ipa->address[0] == 0 ? US"\"all IPv4\"" :
1379 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
1380
059ec3d9 1381 ipa->port = default_smtp_port[0];
d7978c0f 1382 for (int i = 1; default_smtp_port[i] > 0; i++)
059ec3d9 1383 {
f3ebb786 1384 ip_address_item *new = store_get(sizeof(ip_address_item), FALSE);
b891534f 1385
059ec3d9
PH
1386 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1387 new->port = default_smtp_port[i];
1388 new->next = ipa->next;
1389 ipa->next = new;
1390 ipa = new;
1391 }
1392 }
1393
1394 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1395 wildcard for the same port, ensure that (a) they are together and (b) the
1396 IPv6 address comes first. This makes handling the messy features easier, and
1397 also simplifies the construction of the "daemon started" log line. */
1398
1399 pipa = &addresses;
b891534f 1400 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
059ec3d9
PH
1401 {
1402 ip_address_item *ipa2;
1403
1404 /* Handle an IPv4 wildcard */
1405
1406 if (ipa->address[0] == 0)
b891534f 1407 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
059ec3d9
PH
1408 {
1409 ip_address_item *ipa3 = ipa2->next;
1410 if (ipa3->address[0] == ':' &&
1411 ipa3->address[1] == 0 &&
1412 ipa3->port == ipa->port)
1413 {
1414 ipa2->next = ipa3->next;
1415 ipa3->next = ipa;
1416 *pipa = ipa3;
1417 break;
1418 }
1419 }
059ec3d9
PH
1420
1421 /* Handle an IPv6 wildcard. */
1422
1423 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
b891534f 1424 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
059ec3d9
PH
1425 {
1426 ip_address_item *ipa3 = ipa2->next;
1427 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1428 {
1429 ipa2->next = ipa3->next;
1430 ipa3->next = ipa->next;
1431 ipa->next = ipa3;
1432 ipa = ipa3;
1433 break;
1434 }
1435 }
059ec3d9
PH
1436 }
1437
1438 /* Get a vector to remember all the sockets in */
1439
b891534f 1440 for (ipa = addresses; ipa; ipa = ipa->next)
059ec3d9 1441 listen_socket_count++;
f3ebb786 1442 listen_sockets = store_get(sizeof(int) * listen_socket_count, FALSE);
059ec3d9 1443
9ee44efb
PP
1444 } /* daemon_listen but not inetd_wait_mode */
1445
8768d548 1446if (f.daemon_listen)
9ee44efb
PP
1447 {
1448
059ec3d9
PH
1449 /* Do a sanity check on the max connects value just to save us from getting
1450 a huge amount of store. */
1451
1452 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1453
1454 /* There's no point setting smtp_accept_queue unless it is less than the max
1455 connects limit. The configuration reader ensures that the max is set if the
1456 queue-only option is set. */
1457
1458 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1459
1460 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1461 track of them for total number and queue/host limits. */
1462
1463 if (smtp_accept_max > 0)
1464 {
f3ebb786 1465 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), FALSE);
d7978c0f 1466 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
059ec3d9
PH
1467 }
1468 }
1469
76a2d7ba
PH
1470/* The variable background_daemon is always false when debugging, but
1471can also be forced false in order to keep a non-debugging daemon in the
1472foreground. If background_daemon is true, close all open file descriptors that
9ee44efb
PP
1473we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1474do this for inetd_wait mode.
76a2d7ba
PH
1475
1476This is protection against any called functions (in libraries, or in
1477Perl, or whatever) that think they can write to stderr (or stdout). Before this
1478was added, it was quite likely that an SMTP connection would use one of these
1479file descriptors, in which case writing random stuff to it caused chaos.
1480
1481Then disconnect from the controlling terminal, Most modern Unixes seem to have
1482setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1483setsid() can be #defined as a no-op, or as something else. */
059ec3d9 1484
8768d548 1485if (f.background_daemon || f.inetd_wait_mode)
059ec3d9 1486 {
76a2d7ba
PH
1487 log_close_all(); /* Just in case anything was logged earlier */
1488 search_tidyup(); /* Just in case any were used in reading the config. */
f1e894f3
PH
1489 (void)close(0); /* Get rid of stdin/stdout/stderr */
1490 (void)close(1);
1491 (void)close(2);
8e669ac1 1492 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
059ec3d9 1493 log_stderr = NULL; /* So no attempt to copy paniclog output */
9ee44efb 1494 }
059ec3d9 1495
8768d548 1496if (f.background_daemon)
9ee44efb 1497 {
059ec3d9 1498 /* If the parent process of this one has pid == 1, we are re-initializing the
8e669ac1 1499 daemon as the result of a SIGHUP. In this case, there is no need to do
76a2d7ba
PH
1500 anything, because the controlling terminal has long gone. Otherwise, fork, in
1501 case current process is a process group leader (see 'man setsid' for an
1502 explanation) before calling setsid(). */
059ec3d9
PH
1503
1504 if (getppid() != 1)
1505 {
1506 pid_t pid = fork();
1507 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1508 "fork() failed when starting daemon: %s", strerror(errno));
1509 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1510 (void)setsid(); /* release controlling terminal */
1511 }
1512 }
1513
1514/* We are now in the disconnected, daemon process (unless debugging). Set up
1515the listening sockets if required. */
1516
4c2efd7a 1517daemon_notifier_socket();
ff966302 1518
8768d548 1519if (f.daemon_listen && !f.inetd_wait_mode)
059ec3d9
PH
1520 {
1521 int sk;
059ec3d9
PH
1522 ip_address_item *ipa;
1523
1524 /* For each IP address, create a socket, bind it to the appropriate port, and
1525 start listening. See comments above about IPv6 sockets that may or may not
1526 accept IPv4 calls when listening on all interfaces. We also have to cope with
1527 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1528 listening, provided a wildcard IPv4 socket for the same port follows. */
1529
1530 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1531 {
1532 BOOL wildcard;
1533 ip_address_item *ipa2;
059ec3d9
PH
1534 int af;
1535
1536 if (Ustrchr(ipa->address, ':') != NULL)
1537 {
1538 af = AF_INET6;
1539 wildcard = ipa->address[1] == 0;
1540 }
1541 else
1542 {
1543 af = AF_INET;
1544 wildcard = ipa->address[0] == 0;
1545 }
1546
96f5fe4c 1547 if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0)
059ec3d9
PH
1548 {
1549 if (check_special_case(0, addresses, ipa, FALSE))
1550 {
1551 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1552 "listening (%s): will use IPv4", strerror(errno));
1553 goto SKIP_SOCKET;
1554 }
1555 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1556 (af == AF_INET6)? '6' : '4', strerror(errno));
1557 }
1558
1559 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1560 available. Just log failure (can get protocol not available, just like
1561 socket creation can). */
1562
b891534f 1563#ifdef IPV6_V6ONLY
059ec3d9 1564 if (af == AF_INET6 && wildcard &&
5903c6ff 1565 setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, CS (&on),
059ec3d9
PH
1566 sizeof(on)) < 0)
1567 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1568 "socket failed (%s): carrying on without it", strerror(errno));
b891534f 1569#endif /* IPV6_V6ONLY */
059ec3d9
PH
1570
1571 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1572 is being handled. Without this, a connection will prevent reuse of the
1573 smtp port for listening. */
1574
1575 if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR,
5903c6ff 1576 US (&on), sizeof(on)) < 0)
059ec3d9
PH
1577 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1578 "failed when starting daemon: %s", strerror(errno));
1579
1580 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1581 disable this because it breaks some broken clients. */
1582
1583 if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY,
5903c6ff 1584 US (&on), sizeof(on));
059ec3d9
PH
1585
1586 /* Now bind the socket to the required port; if Exim is being restarted
1587 it may not always be possible to bind immediately, even with SO_REUSEADDR
1588 set, so try 10 times, waiting between each try. After 10 failures, we give
1589 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1590 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1591 address for the same port, ignore the error on the grounds that we must be
1592 in a system where the IPv6 socket accepts both kinds of call. This is
1593 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1594 listen() stage instead. */
1595
6af7e591 1596#ifdef TCP_FASTOPEN
8768d548 1597 f.tcp_fastopen_ok = TRUE;
6af7e591 1598#endif
059ec3d9
PH
1599 for(;;)
1600 {
1601 uschar *msg, *addr;
1602 if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break;
1603 if (check_special_case(errno, addresses, ipa, TRUE))
1604 {
1605 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1606 "listen() success; EADDRINUSE ignored\n");
f1e894f3 1607 (void)close(listen_sockets[sk]);
059ec3d9
PH
1608 goto SKIP_SOCKET;
1609 }
1610 msg = US strerror(errno);
b891534f
JH
1611 addr = wildcard
1612 ? af == AF_INET6
1613 ? US"(any IPv6)"
1614 : US"(any IPv4)"
1615 : ipa->address;
4aee0225 1616 if (daemon_startup_retries <= 0)
059ec3d9
PH
1617 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1618 "socket bind() to port %d for address %s failed: %s: "
1619 "daemon abandoned", ipa->port, addr, msg);
1620 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
4aee0225
PH
1621 "failed: %s: waiting %s before trying again (%d more %s)",
1622 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1623 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1624 daemon_startup_retries--;
1625 sleep(daemon_startup_sleep);
059ec3d9
PH
1626 }
1627
1628 DEBUG(D_any)
059ec3d9
PH
1629 if (wildcard)
1630 debug_printf("listening on all interfaces (IPv%c) port %d\n",
fb05276a 1631 af == AF_INET6 ? '6' : '4', ipa->port);
059ec3d9
PH
1632 else
1633 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
fb05276a 1634
b536a578 1635#if defined(TCP_FASTOPEN) && !defined(__APPLE__)
590faf89
JH
1636 if ( f.tcp_fastopen_ok
1637 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
4670e9d3 1638 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
6af7e591 1639 {
a23ff3b4 1640 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
8768d548 1641 f.tcp_fastopen_ok = FALSE;
6af7e591 1642 }
fb05276a 1643#endif
059ec3d9
PH
1644
1645 /* Start listening on the bound socket, establishing the maximum backlog of
1646 connections that is allowed. On success, continue to the next address. */
1647
b536a578
JH
1648 if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0)
1649 {
1650#if defined(TCP_FASTOPEN) && defined(__APPLE__)
1651 if ( f.tcp_fastopen_ok
1652 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1653 &on, sizeof(on)))
1654 {
1655 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1656 f.tcp_fastopen_ok = FALSE;
1657 }
1658#endif
1659 continue;
1660 }
059ec3d9
PH
1661
1662 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1663 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1664 and there was a previous successful IPv6 wildcard listen on the same port,
1665 we want to ignore the error on the grounds that we must be in a system
1666 where the IPv6 socket accepts both kinds of call. */
1667
1668 if (!check_special_case(errno, addresses, ipa, TRUE))
1669 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
fb05276a
JH
1670 wildcard
1671 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
059ec3d9
PH
1672 strerror(errno));
1673
1674 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1675 "listen() success; EADDRINUSE ignored\n");
f1e894f3 1676 (void)close(listen_sockets[sk]);
059ec3d9
PH
1677
1678 /* Come here if there has been a problem with the socket which we
1679 are going to ignore. We remove the address from the chain, and back up the
1680 counts. */
1681
b891534f 1682 SKIP_SOCKET:
059ec3d9
PH
1683 sk--; /* Back up the count */
1684 listen_socket_count--; /* Reduce the total */
1685 if (ipa == addresses) addresses = ipa->next; else
1686 {
1687 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1688 ipa2->next = ipa->next;
1689 ipa = ipa2;
1690 }
1691 } /* End of bind/listen loop for each address */
1692 } /* End of setup for listening */
1693
1694
1695/* If we are not listening, we want to write a pid file only if -oP was
1696explicitly given. */
1697
b891534f
JH
1698else if (!override_pid_file_path)
1699 write_pid = FALSE;
059ec3d9
PH
1700
1701/* Write the pid to a known file for assistance in identification, if required.
1702We do this before giving up root privilege, because on some systems it is
1703necessary to be root in order to write into the pid file directory. There's
1704nothing to stop multiple daemons running, as long as no more than one listens
1705on a given TCP/IP port on the same interface(s). However, in these
1706circumstances it gets far too complicated to mess with pid file names
1707automatically. Consequently, Exim 4 writes a pid file only
1708
1709 (a) When running in the test harness, or
1710 (b) When -bd is used and -oX is not used, or
1711 (c) When -oP is used to supply a path.
1712
1713The variable daemon_write_pid is used to control this. */
1714
8768d548 1715if (f.running_in_test_harness || write_pid)
059ec3d9
PH
1716 {
1717 FILE *f;
1718
01446a56 1719 set_pid_file_path();
b891534f 1720 if ((f = modefopen(pid_file_path, "wb", 0644)))
059ec3d9 1721 {
ff790e47 1722 (void)fprintf(f, "%d\n", (int)getpid());
ff790e47 1723 (void)fclose(f);
059ec3d9
PH
1724 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1725 }
1726 else
059ec3d9
PH
1727 DEBUG(D_any)
1728 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
1729 pid_file_path));
059ec3d9
PH
1730 }
1731
1732/* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1733
1734sighup_seen = FALSE;
1735signal(SIGHUP, sighup_handler);
1736
1737/* Give up root privilege at this point (assuming that exim_uid and exim_gid
1738are not root). The third argument controls the running of initgroups().
1739Normally we do this, in order to set up the groups for the Exim user. However,
1740if we are not root at this time - some odd installations run that way - we
1741cannot do this. */
1742
1743exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1744
ebeaf996
PH
1745/* Update the originator_xxx fields so that received messages as listed as
1746coming from Exim, not whoever started the daemon. */
1747
1748originator_uid = exim_uid;
1749originator_gid = exim_gid;
f3ebb786
JH
1750originator_login = (pw = getpwuid(exim_uid))
1751 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
ebeaf996 1752
059ec3d9
PH
1753/* Get somewhere to keep the list of queue-runner pids if we are keeping track
1754of them (and also if we are doing queue runs). */
1755
0cd5fd23 1756if (queue_interval > 0 && local_queue_run_max > 0)
059ec3d9 1757 {
f3ebb786 1758 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t), FALSE);
d7978c0f 1759 for (int i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
059ec3d9
PH
1760 }
1761
01446a56
JH
1762/* Set up the handler for termination of child processes, and the one
1763telling us to die. */
059ec3d9
PH
1764
1765sigchld_seen = FALSE;
7d468ab8 1766os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
059ec3d9 1767
01446a56
JH
1768sigterm_seen = FALSE;
1769os_non_restarting_signal(SIGTERM, main_sigterm_handler);
1770
059ec3d9
PH
1771/* If we are to run the queue periodically, pretend the alarm has just gone
1772off. This will cause the first queue-runner to get kicked off straight away. */
1773
1774sigalrm_seen = (queue_interval > 0);
1775
1776/* Log the start up of a daemon - at least one of listening or queue running
1777must be set up. */
1778
8768d548 1779if (f.inetd_wait_mode)
9ee44efb
PP
1780 {
1781 uschar *p = big_buffer;
1782
1783 if (inetd_wait_timeout >= 0)
1784 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
1785 else
1786 sprintf(CS p, "with no wait timeout");
1787
1788 log_write(0, LOG_MAIN,
1789 "exim %s daemon started: pid=%d, launched with listening socket, %s",
1790 version_string, getpid(), big_buffer);
2f21487f 1791 set_process_info("daemon(%s): pre-listening socket", version_string);
9ee44efb
PP
1792
1793 /* set up the timeout logic */
ff966302 1794 sigalrm_seen = TRUE;
9ee44efb
PP
1795 }
1796
8768d548 1797else if (f.daemon_listen)
059ec3d9 1798 {
059ec3d9
PH
1799 int smtp_ports = 0;
1800 int smtps_ports = 0;
254f38d1
JH
1801 ip_address_item * ipa;
1802 uschar * p;
e37f8a84
JH
1803 uschar * qinfo = queue_interval > 0
1804 ? string_sprintf("-q%s", readconf_printtime(queue_interval))
1805 : US"no queue runs";
059ec3d9
PH
1806
1807 /* Build a list of listening addresses in big_buffer, but limit it to 10
1808 items. The style is for backwards compatibility.
1809
1810 It is now possible to have some ports listening for SMTPS (the old,
1811 deprecated protocol that starts TLS without using STARTTLS), and others
1812 listening for standard SMTP. Keep their listings separate. */
1813
254f38d1 1814 for (int j = 0, i; j < 2; j++)
059ec3d9 1815 {
e37f8a84 1816 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
b891534f
JH
1817 {
1818 /* First time round, look for SMTP ports; second time round, look for
254f38d1 1819 SMTPS ports. Build IP+port strings. */
b891534f
JH
1820
1821 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1822 {
1823 if (j == 0)
254f38d1 1824 smtp_ports++;
b891534f 1825 else
254f38d1 1826 smtps_ports++;
b891534f
JH
1827
1828 /* Now the information about the port (and sometimes interface) */
1829
1830 if (ipa->address[0] == ':' && ipa->address[1] == 0)
e4d0fc93 1831 { /* v6 wildcard */
b891534f
JH
1832 if (ipa->next && ipa->next->address[0] == 0 &&
1833 ipa->next->port == ipa->port)
1834 {
254f38d1
JH
1835 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
1836 (ipa = ipa->next)->log = NULL;
b891534f
JH
1837 }
1838 else if (ipa->v6_include_v4)
254f38d1 1839 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
b891534f 1840 else
254f38d1 1841 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
b891534f 1842 }
e4d0fc93 1843 else if (ipa->address[0] == 0) /* v4 wildcard */
254f38d1 1844 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
e4d0fc93 1845 else /* check for previously-seen IP */
b891534f 1846 {
254f38d1 1847 ip_address_item * i2;
e4d0fc93
JH
1848 for (i2 = addresses; i2 != ipa; i2 = i2->next)
1849 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
1850 && Ustrcmp(ipa->address, i2->address) == 0
1851 )
1852 { /* found; append port to list */
254f38d1
JH
1853 for (p = i2->log; *p; ) p++; /* end of existing string */
1854 if (*--p == '}') *p = '\0'; /* drop EOL */
1855 while (isdigit(*--p)) ; /* char before port */
1856
1857 i2->log = *p == ':' /* no list yet? */
1858 ? string_sprintf("%.*s{%s,%d}",
1859 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
1860 : string_sprintf("%s,%d}", i2->log, ipa->port);
1861 ipa->log = NULL;
e4d0fc93
JH
1862 break;
1863 }
1864 if (i2 == ipa) /* first-time IP */
254f38d1 1865 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
b891534f 1866 }
b891534f
JH
1867 }
1868 }
254f38d1 1869 }
059ec3d9 1870
254f38d1
JH
1871 p = big_buffer;
1872 for (int j = 0, i; j < 2; j++)
1873 {
1874 /* First time round, look for SMTP ports; second time round, look for
1875 SMTPS ports. For the first one of each, insert leading text. */
1876
1877 if (j == 0)
059ec3d9 1878 {
254f38d1
JH
1879 if (smtp_ports > 0)
1880 p += sprintf(CS p, "SMTP on");
059ec3d9 1881 }
254f38d1
JH
1882 else
1883 if (smtps_ports > 0)
1884 p += sprintf(CS p, "%sSMTPS on",
1885 smtp_ports == 0 ? "" : " and for ");
1886
1887 /* Now the information about the port (and sometimes interface) */
1888
1889 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
1890 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1891 if (ipa->log)
1892 p += sprintf(CS p, "%s", ipa->log);
1893
1894 if (ipa)
1895 p += sprintf(CS p, " ...");
059ec3d9
PH
1896 }
1897
1898 log_write(0, LOG_MAIN,
1899 "exim %s daemon started: pid=%d, %s, listening for %s",
1900 version_string, getpid(), qinfo, big_buffer);
44915474
JH
1901 set_process_info("daemon(%s): %s, listening for %s",
1902 version_string, qinfo, big_buffer);
059ec3d9
PH
1903 }
1904
1905else
1906 {
44915474
JH
1907 uschar * s = *queue_name
1908 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
1909 : string_sprintf("-q%s", readconf_printtime(queue_interval));
059ec3d9 1910 log_write(0, LOG_MAIN,
44915474
JH
1911 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
1912 version_string, getpid(), s);
1913 set_process_info("daemon(%s): %s, not listening", version_string, s);
059ec3d9
PH
1914 }
1915
476be7e2
JH
1916/* Do any work it might be useful to amortize over our children
1917(eg: compile regex) */
1918
476be7e2 1919dns_pattern_init();
d85cdeb5
JH
1920smtp_deliver_init(); /* Used for callouts */
1921
1922#ifndef DISABLE_DKIM
1923 {
1924# ifdef MEASURE_TIMING
1925 struct timeval t0;
1926 gettimeofday(&t0, NULL);
1927# endif
1928 dkim_exim_init();
1929# ifdef MEASURE_TIMING
1930 report_time_since(&t0, US"dkim_exim_init (delta)");
1931# endif
1932 }
1933#endif
476be7e2
JH
1934
1935#ifdef WITH_CONTENT_SCAN
1936malware_init();
1937#endif
73ec116f
JH
1938#ifdef SUPPORT_SPF
1939spf_init();
1940#endif
059ec3d9
PH
1941
1942/* Close the log so it can be renamed and moved. In the few cases below where
1943this long-running process writes to the log (always exceptional conditions), it
1944closes the log afterwards, for the same reason. */
1945
1946log_close_all();
1947
1948DEBUG(D_any) debug_print_ids(US"daemon running with");
1949
1950/* Any messages accepted via this route are going to be SMTP. */
1951
1952smtp_input = TRUE;
1953
9f01e50d
JH
1954#ifdef MEASURE_TIMING
1955report_time_since(&timestamp_startup, US"daemon loop start"); /* testcase 0022 */
1956#endif
1957
059ec3d9
PH
1958/* Enter the never-ending loop... */
1959
1960for (;;)
1961 {
1962 #if HAVE_IPV6
1963 struct sockaddr_in6 accepted;
1964 #else
1965 struct sockaddr_in accepted;
1966 #endif
1967
cf73943b 1968 EXIM_SOCKLEN_T len;
059ec3d9
PH
1969 pid_t pid;
1970
01446a56
JH
1971 if (sigterm_seen)
1972 daemon_die(); /* Does not return */
1973
059ec3d9 1974 /* This code is placed first in the loop, so that it gets obeyed at the
9ee44efb
PP
1975 start, before the first wait, for the queue-runner case, so that the first
1976 one can be started immediately.
1977
1978 The other option is that we have an inetd wait timeout specified to -bw. */
059ec3d9
PH
1979
1980 if (sigalrm_seen)
1981 {
9ee44efb
PP
1982 if (inetd_wait_timeout > 0)
1983 {
1984 time_t resignal_interval = inetd_wait_timeout;
1985
1986 if (last_connection_time == (time_t)0)
1987 {
1988 DEBUG(D_any)
1989 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
1990 }
1991 else
1992 {
1993 time_t now = time(NULL);
1994 if (now == (time_t)-1)
1995 {
1996 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
1997 }
1998 else
1999 {
2000 if ((now - last_connection_time) >= inetd_wait_timeout)
2001 {
2002 DEBUG(D_any)
2003 debug_printf("inetd wait timeout %d expired, ending daemon\n",
2004 inetd_wait_timeout);
2005 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
2006 version_string);
2007 exit(EXIT_SUCCESS);
2008 }
2009 else
2010 {
2011 resignal_interval -= (now - last_connection_time);
2012 }
2013 }
2014 }
059ec3d9 2015
9ee44efb 2016 sigalrm_seen = FALSE;
c2a1bba0 2017 ALARM(resignal_interval);
9ee44efb 2018 }
059ec3d9 2019
9ee44efb 2020 else
059ec3d9 2021 {
ff966302
JH
2022 DEBUG(D_any) debug_printf("%s received\n",
2023#ifdef EXPERIMENTAL_QUEUE_RAMP
2024 *queuerun_msgid ? "qrun notification" :
2025#endif
2026 "SIGALRM");
8e669ac1 2027
9ee44efb
PP
2028 /* Do a full queue run in a child process, if required, unless we already
2029 have enough queue runners on the go. If we are not running as root, a
2030 re-exec is required. */
059ec3d9 2031
9ee44efb 2032 if (queue_interval > 0 &&
0cd5fd23 2033 (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
9ee44efb
PP
2034 {
2035 if ((pid = fork()) == 0)
2036 {
9ee44efb
PP
2037 DEBUG(D_any) debug_printf("Starting queue-runner: pid %d\n",
2038 (int)getpid());
8e669ac1 2039
9ee44efb
PP
2040 /* Disable debugging if it's required only for the daemon process. We
2041 leave the above message, because it ties up with the "child ended"
2042 debugging messages. */
059ec3d9 2043
8768d548 2044 if (f.debug_daemon) debug_selector = 0;
059ec3d9 2045
9ee44efb 2046 /* Close any open listening sockets in the child */
059ec3d9 2047
ff966302
JH
2048 if (daemon_notifier_fd >= 0)
2049 (void) close(daemon_notifier_fd);
d7978c0f 2050 for (int sk = 0; sk < listen_socket_count; sk++)
ff966302 2051 (void) close(listen_sockets[sk]);
059ec3d9 2052
9ee44efb 2053 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
059ec3d9 2054
9ee44efb
PP
2055 signal(SIGHUP, SIG_DFL);
2056 signal(SIGCHLD, SIG_DFL);
01446a56 2057 signal(SIGTERM, SIG_DFL);
059ec3d9 2058
9ee44efb
PP
2059 /* Re-exec if privilege has been given up, unless deliver_drop_
2060 privilege is set. Reset SIGALRM before exec(). */
4fbcfc2e 2061
9ee44efb 2062 if (geteuid() != root_uid && !deliver_drop_privilege)
4fbcfc2e 2063 {
9ee44efb
PP
2064 uschar opt[8];
2065 uschar *p = opt;
ff966302 2066 uschar *extra[7];
9ee44efb
PP
2067 int extracount = 1;
2068
2069 signal(SIGALRM, SIG_DFL);
2070 *p++ = '-';
2071 *p++ = 'q';
ff966302
JH
2072 if ( f.queue_2stage
2073#ifdef EXPERIMENTAL_QUEUE_RAMP
2074 && !*queuerun_msgid
2075#endif
2076 ) *p++ = 'q';
8768d548
JH
2077 if (f.queue_run_first_delivery) *p++ = 'i';
2078 if (f.queue_run_force) *p++ = 'f';
2079 if (f.deliver_force_thaw) *p++ = 'f';
2080 if (f.queue_run_local) *p++ = 'l';
9ee44efb 2081 *p = 0;
3f008c60 2082 extra[0] = *queue_name
e37f8a84 2083 ? string_sprintf("%sG%s", opt, queue_name) : opt;
9ee44efb 2084
ff966302
JH
2085#ifdef EXPERIMENTAL_QUEUE_RAMP
2086 if (*queuerun_msgid)
2087 {
2088 extra[extracount++] = queuerun_msgid; /* Trigger only the */
2089 extra[extracount++] = queuerun_msgid; /* one message */
2090 }
2091#endif
2092
9ee44efb
PP
2093 /* If -R or -S were on the original command line, ensure they get
2094 passed on. */
2095
e37f8a84 2096 if (deliver_selectstring)
9ee44efb 2097 {
8768d548 2098 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
9ee44efb
PP
2099 extra[extracount++] = deliver_selectstring;
2100 }
2101
e37f8a84 2102 if (deliver_selectstring_sender)
9ee44efb 2103 {
8768d548 2104 extra[extracount++] = f.deliver_selectstring_sender_regex
e37f8a84 2105 ? US"-Sr" : US"-S";
9ee44efb
PP
2106 extra[extracount++] = deliver_selectstring_sender;
2107 }
2108
2109 /* Overlay this process with a new execution. */
2110
ff966302
JH
2111 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
2112 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
9ee44efb
PP
2113
2114 /* Control never returns here. */
4fbcfc2e
PH
2115 }
2116
9ee44efb 2117 /* No need to re-exec; SIGALRM remains set to the default handler */
059ec3d9 2118
ff966302
JH
2119#ifdef EXPERIMENTAL_QUEUE_RAMP
2120 if (*queuerun_msgid)
2121 {
2122 f.queue_2stage = FALSE;
2123 queue_run(queuerun_msgid, queuerun_msgid, FALSE);
2124 }
2125 else
2126#endif
2127 queue_run(NULL, NULL, FALSE);
f3ebb786 2128 exim_underbar_exit(EXIT_SUCCESS);
059ec3d9
PH
2129 }
2130
9ee44efb 2131 if (pid < 0)
059ec3d9 2132 {
9ee44efb
PP
2133 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
2134 "process failed: %s", strerror(errno));
2135 log_close_all();
2136 }
2137 else
2138 {
d7978c0f 2139 for (int i = 0; i < local_queue_run_max; ++i)
9ee44efb
PP
2140 if (queue_pid_slots[i] <= 0)
2141 {
2142 queue_pid_slots[i] = pid;
2143 queue_run_count++;
2144 break;
2145 }
9ee44efb 2146 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
d7978c0f 2147 queue_run_count, queue_run_count == 1 ? "" : "es");
059ec3d9 2148 }
059ec3d9 2149 }
059ec3d9 2150
9ee44efb 2151 /* Reset the alarm clock */
059ec3d9 2152
9ee44efb 2153 sigalrm_seen = FALSE;
ff966302
JH
2154#ifdef EXPERIMENTAL_QUEUE_RAMP
2155 if (*queuerun_msgid)
2156 *queuerun_msgid = 0;
2157 else
2158#endif
2159 ALARM(queue_interval);
9ee44efb
PP
2160 }
2161
2162 } /* sigalrm_seen */
059ec3d9
PH
2163
2164
2165 /* Sleep till a connection happens if listening, and handle the connection if
2166 that is why we woke up. The FreeBSD operating system requires the use of
2167 select() before accept() because the latter function is not interrupted by
2168 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2169 OS do notice signals in accept() but it does no harm to have the select()
2170 in for all of them - and it won't then be a lurking problem for ports to
2171 new OS. In fact, the later addition of listening on specific interfaces only
2172 requires this way of working anyway. */
2173
8768d548 2174 if (f.daemon_listen)
059ec3d9 2175 {
d7978c0f 2176 int lcount, select_errno;
059ec3d9
PH
2177 int max_socket = 0;
2178 BOOL select_failed = FALSE;
2179 fd_set select_listen;
2180
2181 FD_ZERO(&select_listen);
ff966302
JH
2182 if (daemon_notifier_fd >= 0)
2183 FD_SET(daemon_notifier_fd, &select_listen);
d7978c0f 2184 for (int sk = 0; sk < listen_socket_count; sk++)
059ec3d9
PH
2185 {
2186 FD_SET(listen_sockets[sk], &select_listen);
2187 if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk];
2188 }
2189
2190 DEBUG(D_any) debug_printf("Listening...\n");
8e669ac1
PH
2191
2192 /* In rare cases we may have had a SIGCHLD signal in the time between
2193 setting the handler (below) and getting back here. If so, pretend that the
7d468ab8 2194 select() was interrupted so that we reap the child. This might still leave
8e669ac1 2195 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
7d468ab8
PH
2196 only to do the reaping more quickly, it shouldn't result in anything other
2197 than a delay until something else causes a wake-up. */
2198
2199 if (sigchld_seen)
2200 {
2201 lcount = -1;
8e669ac1 2202 errno = EINTR;
7d468ab8
PH
2203 }
2204 else
7d468ab8
PH
2205 lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen,
2206 NULL, NULL, NULL);
059ec3d9 2207
7d468ab8 2208 if (lcount < 0)
059ec3d9
PH
2209 {
2210 select_failed = TRUE;
2211 lcount = 1;
2212 }
8e669ac1
PH
2213
2214 /* Clean up any subprocesses that may have terminated. We need to do this
2215 here so that smtp_accept_max_per_host works when a connection to that host
2216 has completed, and we are about to accept a new one. When this code was
2217 later in the sequence, a new connection could be rejected, even though an
2218 old one had just finished. Preserve the errno from any select() failure for
bb6e88ff 2219 the use of the common select/accept error processing below. */
8e669ac1 2220
bb6e88ff
PH
2221 select_errno = errno;
2222 handle_ending_processes();
8e669ac1
PH
2223 errno = select_errno;
2224
01603eec 2225#ifndef DISABLE_TLS
b10c87b3
JH
2226 /* Create or rotate any required keys */
2227 tls_daemon_init();
2228#endif
2229
059ec3d9 2230 /* Loop for all the sockets that are currently ready to go. If select
7d468ab8
PH
2231 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2232 to use the common error code for select/accept below. */
059ec3d9
PH
2233
2234 while (lcount-- > 0)
2235 {
2236 int accept_socket = -1;
6851a9c5 2237
059ec3d9 2238 if (!select_failed)
ff966302 2239 {
ff966302
JH
2240 if ( daemon_notifier_fd >= 0
2241 && FD_ISSET(daemon_notifier_fd, &select_listen))
2242 {
2243 FD_CLR(daemon_notifier_fd, &select_listen);
2244 sigalrm_seen = daemon_notification();
2245 break; /* to top of daemon loop */
2246 }
d7978c0f 2247 for (int sk = 0; sk < listen_socket_count; sk++)
059ec3d9
PH
2248 if (FD_ISSET(listen_sockets[sk], &select_listen))
2249 {
cf73943b 2250 len = sizeof(accepted);
059ec3d9
PH
2251 accept_socket = accept(listen_sockets[sk],
2252 (struct sockaddr *)&accepted, &len);
2253 FD_CLR(listen_sockets[sk], &select_listen);
2254 break;
2255 }
ff966302 2256 }
059ec3d9
PH
2257
2258 /* If select or accept has failed and this was not caused by an
2259 interruption, log the incident and try again. With asymmetric TCP/IP
2260 routing errors such as "No route to network" have been seen here. Also
2261 "connection reset by peer" has been seen. These cannot be classed as
2262 disastrous errors, but they could fill up a lot of log. The code in smail
2263 crashes the daemon after 10 successive failures of accept, on the grounds
2264 that some OS fail continuously. Exim originally followed suit, but this
2265 appears to have caused problems. Now it just keeps going, but instead of
2266 logging each error, it batches them up when they are continuous. */
2267
2268 if (accept_socket < 0 && errno != EINTR)
2269 {
2270 if (accept_retry_count == 0)
2271 {
2272 accept_retry_errno = errno;
2273 accept_retry_select_failed = select_failed;
2274 }
2275 else
2276 {
2277 if (errno != accept_retry_errno ||
2278 select_failed != accept_retry_select_failed ||
2279 accept_retry_count >= 50)
2280 {
2281 log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0),
2282 "%d %s() failure%s: %s",
2283 accept_retry_count,
2284 accept_retry_select_failed? "select" : "accept",
2285 (accept_retry_count == 1)? "" : "s",
2286 strerror(accept_retry_errno));
2287 log_close_all();
2288 accept_retry_count = 0;
2289 accept_retry_errno = errno;
2290 accept_retry_select_failed = select_failed;
2291 }
2292 }
2293 accept_retry_count++;
2294 }
2295
2296 else
2297 {
2298 if (accept_retry_count > 0)
2299 {
2300 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2301 accept_retry_count,
2302 accept_retry_select_failed? "select" : "accept",
2303 (accept_retry_count == 1)? "" : "s",
2304 strerror(accept_retry_errno));
2305 log_close_all();
2306 accept_retry_count = 0;
2307 }
2308 }
2309
2310 /* If select/accept succeeded, deal with the connection. */
2311
2312 if (accept_socket >= 0)
9ee44efb
PP
2313 {
2314 if (inetd_wait_timeout)
2315 last_connection_time = time(NULL);
059ec3d9
PH
2316 handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,
2317 (struct sockaddr *)&accepted);
9ee44efb 2318 }
059ec3d9
PH
2319 }
2320 }
2321
2322 /* If not listening, then just sleep for the queue interval. If we woke
2323 up early the last time for some other signal, it won't matter because
2324 the alarm signal will wake at the right time. This code originally used
2325 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2326 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2327 select() can be used as an interruptible sleep() on all versions of Unix. */
2328
2329 else
2330 {
2331 struct timeval tv;
2332 tv.tv_sec = queue_interval;
2333 tv.tv_usec = 0;
2334 select(0, NULL, NULL, NULL, &tv);
8e669ac1 2335 handle_ending_processes();
059ec3d9
PH
2336 }
2337
2338 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2339 for itself, because it isn't doing the waiting itself. */
2340
2341 if (sigchld_seen)
2342 {
2343 sigchld_seen = FALSE;
7d468ab8 2344 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
059ec3d9
PH
2345 }
2346
2347 /* Handle being woken by SIGHUP. We know at this point that the result
2348 of accept() has been dealt with, so we can re-exec exim safely, first
2349 closing the listening sockets so that they can be reused. Cancel any pending
2350 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2351 that another HUP in quick succession doesn't clobber the new daemon before it
2352 gets going. All log files get closed by the close-on-exec flag; however, if
2353 the exec fails, we need to close the logs. */
2354
2355 if (sighup_seen)
2356 {
059ec3d9
PH
2357 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2358 getpid());
d7978c0f 2359 for (int sk = 0; sk < listen_socket_count; sk++)
f1e894f3 2360 (void)close(listen_sockets[sk]);
c2a1bba0 2361 ALARM_CLR(0);
059ec3d9
PH
2362 signal(SIGHUP, SIG_IGN);
2363 sighup_argv[0] = exim_path;
2364 exim_nullstd();
2365 execv(CS exim_path, (char *const *)sighup_argv);
2366 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2367 getpid(), exim_path, strerror(errno));
2368 log_close_all();
2369 }
2370
2371 } /* End of main loop */
2372
2373/* Control never reaches here */
2374}
2375
071c51f7
JH
2376/* vi: aw ai sw=2
2377*/
059ec3d9 2378/* End of exim_daemon.c */