tidying
[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
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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);
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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
2f2dd3a5
JH
957if (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
01446a56
JH
970if (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 }
985exim_exit(EXIT_SUCCESS, US"daemon");
986}
987
988
ff966302
JH
989/*************************************************
990* Listener socket for local work prompts *
991*************************************************/
992
993static void
994daemon_notifier_socket(void)
995{
996int fd;
997const uschar * where;
3978c243 998struct sockaddr_un sa_un = {.sun_family = AF_UNIX};
04403ab0 999int len;
ff966302 1000
2f2dd3a5 1001DEBUG(D_any) debug_printf("creating notifier socket ");
ff966302 1002
ff966302 1003#ifdef SOCK_CLOEXEC
2f2dd3a5 1004if ((fd = socket(PF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0)
4a9f055c 1005 { where = US"socket"; goto bad; }
ff966302 1006#else
4a9f055c
JH
1007if ((fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0)
1008 { where = US"socket"; goto bad; }
ff966302
JH
1009(void)fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
1010#endif
1011
2f2dd3a5 1012#ifdef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
3978c243 1013sa_un.sun_path[0] = 0; /* Abstract local socket addr - Linux-specific? */
04403ab0 1014len = offsetof(struct sockaddr_un, sun_path) + 1
3978c243
JH
1015 + snprintf(sa_un.sun_path+1, sizeof(sa_un.sun_path)-1, "%s", NOTIFIER_SOCKET_NAME);
1016DEBUG(D_any) debug_printf("@%s\n", sa_un.sun_path+1);
2f2dd3a5
JH
1017#else /* filesystem-visible and persistent; will neeed removal */
1018len = offsetof(struct sockaddr_un, sun_path)
3978c243 1019 + snprintf(sa_un.sun_path, sizeof(sa_un.sun_path), "%s/%s",
2f2dd3a5 1020 spool_directory, NOTIFIER_SOCKET_NAME);
3978c243 1021DEBUG(D_any) debug_printf("%s\n", sa_un.sun_path);
2f2dd3a5 1022#endif
04403ab0 1023
3978c243 1024if (bind(fd, (const struct sockaddr *)&sa_un, len) < 0)
4a9f055c 1025 { where = US"bind"; goto bad; }
ff966302 1026
5399df80 1027#ifdef SO_PASSCRED /* Linux */
2f2dd3a5 1028if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0)
4a9f055c 1029 { where = US"SO_PASSCRED"; goto bad2; }
2f2dd3a5 1030#elif defined(LOCAL_CREDS) /* FreeBSD-ish */
4a9f055c
JH
1031if (setsockopt(fd, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
1032 { where = US"LOCAL_CREDS"; goto bad2; }
2f2dd3a5 1033#endif
ff966302
JH
1034
1035/* debug_printf("%s: fd %d\n", __FUNCTION__, fd); */
1036daemon_notifier_fd = fd;
1037return;
1038
4a9f055c
JH
1039bad2:
1040#ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1041 Uunlink(sa_un.sun_path);
1042#endif
ff966302 1043bad:
4a9f055c 1044 log_write(0, LOG_MAIN|LOG_PANIC, "%s %s: %s",
ff966302 1045 __FUNCTION__, where, strerror(errno));
4a9f055c
JH
1046 close(fd);
1047 return;
ff966302
JH
1048}
1049
1050
1051static uschar queuerun_msgid[MESSAGE_ID_LENGTH+1];
1052
1053/* Return TRUE if a sigalrm should be emulated */
1054static BOOL
1055daemon_notification(void)
1056{
1057uschar buf[256], cbuf[256];
3978c243 1058struct sockaddr_un sa_un;
017de05c 1059struct iovec iov = {.iov_base = buf, .iov_len = sizeof(buf)-1};
3978c243
JH
1060struct msghdr msg = { .msg_name = &sa_un,
1061 .msg_namelen = sizeof(sa_un),
ff966302
JH
1062 .msg_iov = &iov,
1063 .msg_iovlen = 1,
1064 .msg_control = cbuf,
1065 .msg_controllen = sizeof(cbuf)
1066 };
1067ssize_t sz;
1068struct cmsghdr * cp;
1069
1070buf[sizeof(buf)-1] = 0;
1071if ((sz = recvmsg(daemon_notifier_fd, &msg, 0)) <= 0) return FALSE;
1072if (sz >= sizeof(buf)) return FALSE;
1073
04403ab0
JH
1074#ifdef notdef
1075debug_printf("addrlen %d\n", msg.msg_namelen);
1076#endif
2f2dd3a5 1077DEBUG(D_queue_run) debug_printf("%s from addr '%s%.*s'\n", __FUNCTION__,
3978c243
JH
1078 *sa_un.sun_path ? "" : "@",
1079 (int)msg.msg_namelen - (*sa_un.sun_path ? 0 : 1),
1080 sa_un.sun_path + (*sa_un.sun_path ? 0 : 1));
04403ab0
JH
1081
1082/* Refuse to handle the item unless the peer has good credentials */
f254e592
JH
1083#ifdef SCM_CREDENTIALS
1084# define EXIM_SCM_CR_TYPE SCM_CREDENTIALS
5399df80 1085#elif defined(LOCAL_CREDS) && defined(SCM_CREDS)
f254e592
JH
1086# define EXIM_SCM_CR_TYPE SCM_CREDS
1087#else
2f2dd3a5
JH
1088 /* The OS has no way to get the creds of the caller (for a unix/datagram socket.
1089 Punt; don't try to check. */
f254e592 1090#endif
04403ab0 1091
2f2dd3a5 1092#ifdef EXIM_SCM_CR_TYPE
ff966302
JH
1093for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg);
1094 cp;
1095 cp = CMSG_NXTHDR(&msg, cp))
f254e592 1096 if (cp->cmsg_level == SOL_SOCKET && cp->cmsg_type == EXIM_SCM_CR_TYPE)
ff966302 1097 {
2f2dd3a5 1098# ifdef SCM_CREDENTIALS /* Linux */
ff966302
JH
1099 struct ucred * cr = (struct ucred *) CMSG_DATA(cp);
1100 if (cr->uid && cr->uid != exim_uid)
1101 {
1102 DEBUG(D_queue_run) debug_printf("%s: sender creds pid %d uid %d gid %d\n",
1103 __FUNCTION__, (int)cr->pid, (int)cr->uid, (int)cr->gid);
1104 return FALSE;
2f2dd3a5
JH
1105 }
1106# elif defined(LOCAL_CREDS) /* BSD-ish */
5399df80
JH
1107 struct sockcred * cr = (struct sockcred *) CMSG_DATA(cp);
1108 if (cr->sc_uid && cr->sc_uid != exim_uid)
f254e592 1109 {
5399df80
JH
1110 DEBUG(D_queue_run) debug_printf("%s: sender creds pid ??? uid %d gid %d\n",
1111 __FUNCTION__, (int)cr->sc_uid, (int)cr->sc_gid);
f254e592 1112 return FALSE;
ff966302 1113 }
2f2dd3a5 1114# endif
ff966302
JH
1115 break;
1116 }
2f2dd3a5 1117#endif
ff966302
JH
1118
1119buf[sz] = 0;
1120switch (buf[0])
1121 {
4c2efd7a 1122#ifdef EXPERIMENTAL_QUEUE_RAMP
ff966302
JH
1123 case NOTIFY_MSG_QRUN:
1124 /* this should be a message_id */
1125 DEBUG(D_queue_run)
1126 debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1);
1127 memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1);
1128 return TRUE;
4c2efd7a 1129#endif /*EXPERIMENTAL_QUEUE_RAMP*/
04403ab0
JH
1130
1131 case NOTIFY_QUEUE_SIZE_REQ:
1132 {
1133 uschar buf[16];
1134 int len = snprintf(CS buf, sizeof(buf), "%u", queue_count_cached());
1135
1136 DEBUG(D_queue_run)
1137 debug_printf("%s: queue size request: %s\n", __FUNCTION__, buf);
1138
f254e592 1139 if (sendto(daemon_notifier_fd, buf, len, 0,
3978c243 1140 (const struct sockaddr *)&sa_un, msg.msg_namelen) < 0)
04403ab0
JH
1141 log_write(0, LOG_MAIN|LOG_PANIC,
1142 "%s: sendto: %s\n", __FUNCTION__, strerror(errno));
1143 return FALSE;
1144 }
ff966302
JH
1145 }
1146return FALSE;
1147}
ff966302
JH
1148
1149
059ec3d9
PH
1150/*************************************************
1151* Exim Daemon Mainline *
1152*************************************************/
1153
1154/* The daemon can do two jobs, either of which is optional:
1155
1156(1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1157each one. This is requested by the -bd option, with -oX specifying the SMTP
1158port on which to listen (for testing).
1159
1160(2) Spawns a queue-running process every so often. This is controlled by the
1161-q option with a an interval time. (If no time is given, a single queue run
1162is done from the main function, and control doesn't get here.)
1163
1164Root privilege is required in order to attach to port 25. Some systems require
1165it when calling socket() rather than bind(). To cope with all cases, we run as
1166root for both socket() and bind(). Some systems also require root in order to
1167write to the pid file directory. This function must therefore be called as root
1168if it is to work properly in all circumstances. Once the socket is bound and
1169the pid file written, root privilege is given up if there is an exim uid.
1170
1171There are no arguments to this function, and it never returns. */
1172
1173void
1174daemon_go(void)
1175{
ebeaf996 1176struct passwd *pw;
059ec3d9
PH
1177int *listen_sockets = NULL;
1178int listen_socket_count = 0;
1179ip_address_item *addresses = NULL;
9ee44efb 1180time_t last_connection_time = (time_t)0;
4dc2379a 1181int local_queue_run_max = atoi(CS expand_string(queue_run_max));
059ec3d9
PH
1182
1183/* If any debugging options are set, turn on the D_pid bit so that all
1184debugging lines get the pid added. */
1185
1186DEBUG(D_any|D_v) debug_selector |= D_pid;
1187
8768d548 1188if (f.inetd_wait_mode)
9ee44efb 1189 {
9ee44efb 1190 listen_socket_count = 1;
f3ebb786 1191 listen_sockets = store_get(sizeof(int), FALSE);
9ee44efb
PP
1192 (void) close(3);
1193 if (dup2(0, 3) == -1)
9ee44efb
PP
1194 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1195 "failed to dup inetd socket safely away: %s", strerror(errno));
d4ff61d1 1196
9ee44efb
PP
1197 listen_sockets[0] = 3;
1198 (void) close(0);
1199 (void) close(1);
1200 (void) close(2);
1201 exim_nullstd();
1202
1203 if (debug_file == stderr)
1204 {
1205 /* need a call to log_write before call to open debug_file, so that
1206 log.c:file_path has been initialised. This is unfortunate. */
1207 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1208
1209 fclose(debug_file);
1210 debug_file = NULL;
1211 exim_nullstd(); /* re-open fd2 after we just closed it again */
1212 debug_logging_activate(US"-wait", NULL);
1213 }
1214
1215 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1216
1217 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1218 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1219
d4ff61d1
JH
1220 if (tcp_nodelay)
1221 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1222 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1223 strerror(errno));
9ee44efb
PP
1224 }
1225
1226
8768d548 1227if (f.inetd_wait_mode || f.daemon_listen)
9ee44efb
PP
1228 {
1229 /* If any option requiring a load average to be available during the
1230 reception of a message is set, call os_getloadavg() while we are root
1231 for those OS for which this is necessary the first time it is called (in
1232 order to perform an "open" on the kernel memory file). */
1233
1234 #ifdef LOAD_AVG_NEEDS_ROOT
1235 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1236 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1237 (void)os_getloadavg();
1238 #endif
1239 }
1240
059ec3d9
PH
1241
1242/* Do the preparation for setting up a listener on one or more interfaces, and
1243possible on various ports. This is controlled by the combination of
1244local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1245(which is a list of default ports to use for those items in local_interfaces
1246that do not specify a port). The -oX command line option can be used to
1247override one or both of these options.
1248
1249If local_interfaces is not set, the default is to listen on all interfaces.
1250When it is set, it can include "all IPvx interfaces" as an item. This is useful
1251when different ports are in use.
1252
1253It turns out that listening on all interfaces is messy in an IPv6 world,
1254because several different implementation approaches have been taken. This code
1255is now supposed to work with all of them. The point of difference is whether an
1256IPv6 socket that is listening on all interfaces will receive incoming IPv4
1257calls or not. We also have to cope with the case when IPv6 libraries exist, but
1258there is no IPv6 support in the kernel.
1259
1260. On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1261 addresses. However, if an IPv4 socket is also listening on all interfaces,
1262 calls are directed to the appropriate socket.
1263
1264. On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1265 give them as mapped addresses, but an attempt also to listen on an IPv4
1266 socket on all interfaces causes an error.
1267
1268. On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1269 two sockets if you want to accept both kinds of call.
1270
1271. FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1272 can be turned off, to make it behave like the versions of Linux described
1273 above.
1274
1275. I heard a report that the USAGI IPv6 stack for Linux has implemented
1276 IPV6_V6ONLY.
1277
1278So, what we do when IPv6 is supported is as follows:
1279
1280 (1) After it is set up, the list of interfaces is scanned for wildcard
1281 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1282 port, the list is re-arranged so that they are together, with the IPv6
1283 wildcard first.
1284
1285 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1286 carry on if an IPv4 wildcard socket for the same port follows later in the
1287 list. This allows Exim to carry on in the case when the kernel has no IPv6
1288 support.
1289
1290 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1291 option is defined. However, if setting fails, carry on regardless (but log
1292 the incident).
1293
1294 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1295 error.
1296
1297 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1298 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1299 port (which must have succeeded or we wouldn't have got this far), we
1300 assume we are in the situation where just a single socket is permitted,
1301 and ignore the error.
1302
1303Phew!
1304
1305The preparation code decodes options and sets up the relevant data. We do this
1306first, so that we can return non-zero if there are any syntax errors, and also
1307write to stderr. */
1308
8768d548 1309if (f.daemon_listen && !f.inetd_wait_mode)
059ec3d9
PH
1310 {
1311 int *default_smtp_port;
1312 int sep;
1313 int pct = 0;
1314 uschar *s;
55414b25 1315 const uschar * list;
059ec3d9
PH
1316 uschar *local_iface_source = US"local_interfaces";
1317 ip_address_item *ipa;
1318 ip_address_item **pipa;
1319
059ec3d9
PH
1320 /* If -oX was used, disable the writing of a pid file unless -oP was
1321 explicitly used to force it. Then scan the string given to -oX. Any items
1322 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1323 Any other items are used to override local_interfaces. */
1324
acec9514 1325 if (override_local_interfaces)
059ec3d9 1326 {
acec9514
JH
1327 gstring * new_smtp_port = NULL;
1328 gstring * new_local_interfaces = NULL;
059ec3d9 1329
01446a56 1330 if (!override_pid_file_path) write_pid = FALSE;
059ec3d9
PH
1331
1332 list = override_local_interfaces;
1333 sep = 0;
55414b25 1334 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
059ec3d9
PH
1335 {
1336 uschar joinstr[4];
01446a56 1337 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
059ec3d9 1338
acec9514 1339 if (!*gp)
059ec3d9
PH
1340 {
1341 joinstr[0] = sep;
1342 joinstr[1] = ' ';
acec9514 1343 *gp = string_catn(*gp, US"<", 1);
059ec3d9
PH
1344 }
1345
acec9514
JH
1346 *gp = string_catn(*gp, joinstr, 2);
1347 *gp = string_cat (*gp, s);
059ec3d9
PH
1348 }
1349
acec9514 1350 if (new_smtp_port)
059ec3d9 1351 {
acec9514 1352 daemon_smtp_port = string_from_gstring(new_smtp_port);
059ec3d9
PH
1353 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1354 daemon_smtp_port);
1355 }
1356
acec9514 1357 if (new_local_interfaces)
059ec3d9 1358 {
acec9514 1359 local_interfaces = string_from_gstring(new_local_interfaces);
059ec3d9
PH
1360 local_iface_source = US"-oX data";
1361 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1362 local_interfaces);
1363 }
1364 }
1365
1366 /* Create a list of default SMTP ports, to be used if local_interfaces
4c04137d 1367 contains entries without explicit ports. First count the number of ports, then
059ec3d9
PH
1368 build a translated list in a vector. */
1369
1370 list = daemon_smtp_port;
1371 sep = 0;
55414b25 1372 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
059ec3d9 1373 pct++;
f3ebb786 1374 default_smtp_port = store_get((pct+1) * sizeof(int), FALSE);
059ec3d9
PH
1375 list = daemon_smtp_port;
1376 sep = 0;
1377 for (pct = 0;
55414b25 1378 (s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size));
059ec3d9
PH
1379 pct++)
1380 {
1381 if (isdigit(*s))
1382 {
1383 uschar *end;
1384 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1385 if (end != s + Ustrlen(s))
1386 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1387 }
1388 else
1389 {
1390 struct servent *smtp_service = getservbyname(CS s, "tcp");
071c51f7 1391 if (!smtp_service)
059ec3d9
PH
1392 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1393 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1394 }
1395 }
1396 default_smtp_port[pct] = 0;
1397
071c51f7
JH
1398 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1399
1400 list = tls_in.on_connect_ports;
1401 sep = 0;
1402 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1403 if (!isdigit(*s))
1404 {
acec9514 1405 gstring * g = NULL;
4226691b 1406
071c51f7
JH
1407 list = tls_in.on_connect_ports;
1408 tls_in.on_connect_ports = NULL;
1409 sep = 0;
1410 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1411 {
1412 if (!isdigit(*s))
1413 {
4226691b 1414 struct servent * smtp_service = getservbyname(CS s, "tcp");
071c51f7
JH
1415 if (!smtp_service)
1416 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
4226691b 1417 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
071c51f7 1418 }
acec9514 1419 g = string_append_listele(g, ':', s);
071c51f7 1420 }
acec9514
JH
1421 if (g)
1422 tls_in.on_connect_ports = g->s;
071c51f7
JH
1423 break;
1424 }
1425
059ec3d9
PH
1426 /* Create the list of local interfaces, possibly with ports included. This
1427 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1428 values are converted below. */
1429
1430 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1431
1432 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1433 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1434 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1435 anyway, but we need to know which are the wildcard addresses, and the shorter
1436 strings are neater.
1437
1438 In the same scan, fill in missing port numbers from the default list. When
1439 there is more than one item in the list, extra items are created. */
1440
b891534f 1441 for (ipa = addresses; ipa; ipa = ipa->next)
059ec3d9 1442 {
b891534f
JH
1443 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1444 ipa->address[0] = 0;
059ec3d9
PH
1445 else if (Ustrcmp(ipa->address, "::0") == 0)
1446 {
1447 ipa->address[0] = ':';
1448 ipa->address[1] = 0;
1449 }
1450
1451 if (ipa->port > 0) continue;
1452
1453 if (daemon_smtp_port[0] <= 0)
1454 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1455 "%s and daemon_smtp_port is unset; cannot start daemon",
b891534f
JH
1456 ipa->address[0] == 0 ? US"\"all IPv4\"" :
1457 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
1458
059ec3d9 1459 ipa->port = default_smtp_port[0];
d7978c0f 1460 for (int i = 1; default_smtp_port[i] > 0; i++)
059ec3d9 1461 {
f3ebb786 1462 ip_address_item *new = store_get(sizeof(ip_address_item), FALSE);
b891534f 1463
059ec3d9
PH
1464 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1465 new->port = default_smtp_port[i];
1466 new->next = ipa->next;
1467 ipa->next = new;
1468 ipa = new;
1469 }
1470 }
1471
1472 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1473 wildcard for the same port, ensure that (a) they are together and (b) the
1474 IPv6 address comes first. This makes handling the messy features easier, and
1475 also simplifies the construction of the "daemon started" log line. */
1476
1477 pipa = &addresses;
b891534f 1478 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
059ec3d9
PH
1479 {
1480 ip_address_item *ipa2;
1481
1482 /* Handle an IPv4 wildcard */
1483
1484 if (ipa->address[0] == 0)
b891534f 1485 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
059ec3d9
PH
1486 {
1487 ip_address_item *ipa3 = ipa2->next;
1488 if (ipa3->address[0] == ':' &&
1489 ipa3->address[1] == 0 &&
1490 ipa3->port == ipa->port)
1491 {
1492 ipa2->next = ipa3->next;
1493 ipa3->next = ipa;
1494 *pipa = ipa3;
1495 break;
1496 }
1497 }
059ec3d9
PH
1498
1499 /* Handle an IPv6 wildcard. */
1500
1501 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
b891534f 1502 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
059ec3d9
PH
1503 {
1504 ip_address_item *ipa3 = ipa2->next;
1505 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1506 {
1507 ipa2->next = ipa3->next;
1508 ipa3->next = ipa->next;
1509 ipa->next = ipa3;
1510 ipa = ipa3;
1511 break;
1512 }
1513 }
059ec3d9
PH
1514 }
1515
1516 /* Get a vector to remember all the sockets in */
1517
b891534f 1518 for (ipa = addresses; ipa; ipa = ipa->next)
059ec3d9 1519 listen_socket_count++;
f3ebb786 1520 listen_sockets = store_get(sizeof(int) * listen_socket_count, FALSE);
059ec3d9 1521
9ee44efb
PP
1522 } /* daemon_listen but not inetd_wait_mode */
1523
8768d548 1524if (f.daemon_listen)
9ee44efb
PP
1525 {
1526
059ec3d9
PH
1527 /* Do a sanity check on the max connects value just to save us from getting
1528 a huge amount of store. */
1529
1530 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1531
1532 /* There's no point setting smtp_accept_queue unless it is less than the max
1533 connects limit. The configuration reader ensures that the max is set if the
1534 queue-only option is set. */
1535
1536 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1537
1538 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1539 track of them for total number and queue/host limits. */
1540
1541 if (smtp_accept_max > 0)
1542 {
f3ebb786 1543 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), FALSE);
d7978c0f 1544 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
059ec3d9
PH
1545 }
1546 }
1547
76a2d7ba
PH
1548/* The variable background_daemon is always false when debugging, but
1549can also be forced false in order to keep a non-debugging daemon in the
1550foreground. If background_daemon is true, close all open file descriptors that
9ee44efb
PP
1551we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1552do this for inetd_wait mode.
76a2d7ba
PH
1553
1554This is protection against any called functions (in libraries, or in
1555Perl, or whatever) that think they can write to stderr (or stdout). Before this
1556was added, it was quite likely that an SMTP connection would use one of these
1557file descriptors, in which case writing random stuff to it caused chaos.
1558
1559Then disconnect from the controlling terminal, Most modern Unixes seem to have
1560setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1561setsid() can be #defined as a no-op, or as something else. */
059ec3d9 1562
8768d548 1563if (f.background_daemon || f.inetd_wait_mode)
059ec3d9 1564 {
76a2d7ba
PH
1565 log_close_all(); /* Just in case anything was logged earlier */
1566 search_tidyup(); /* Just in case any were used in reading the config. */
f1e894f3
PH
1567 (void)close(0); /* Get rid of stdin/stdout/stderr */
1568 (void)close(1);
1569 (void)close(2);
8e669ac1 1570 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
059ec3d9 1571 log_stderr = NULL; /* So no attempt to copy paniclog output */
9ee44efb 1572 }
059ec3d9 1573
8768d548 1574if (f.background_daemon)
9ee44efb 1575 {
059ec3d9 1576 /* If the parent process of this one has pid == 1, we are re-initializing the
8e669ac1 1577 daemon as the result of a SIGHUP. In this case, there is no need to do
76a2d7ba
PH
1578 anything, because the controlling terminal has long gone. Otherwise, fork, in
1579 case current process is a process group leader (see 'man setsid' for an
1580 explanation) before calling setsid(). */
059ec3d9
PH
1581
1582 if (getppid() != 1)
1583 {
1584 pid_t pid = fork();
1585 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1586 "fork() failed when starting daemon: %s", strerror(errno));
1587 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1588 (void)setsid(); /* release controlling terminal */
1589 }
1590 }
1591
1592/* We are now in the disconnected, daemon process (unless debugging). Set up
1593the listening sockets if required. */
1594
4c2efd7a 1595daemon_notifier_socket();
ff966302 1596
8768d548 1597if (f.daemon_listen && !f.inetd_wait_mode)
059ec3d9
PH
1598 {
1599 int sk;
059ec3d9
PH
1600 ip_address_item *ipa;
1601
1602 /* For each IP address, create a socket, bind it to the appropriate port, and
1603 start listening. See comments above about IPv6 sockets that may or may not
1604 accept IPv4 calls when listening on all interfaces. We also have to cope with
1605 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1606 listening, provided a wildcard IPv4 socket for the same port follows. */
1607
1608 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1609 {
1610 BOOL wildcard;
1611 ip_address_item *ipa2;
059ec3d9
PH
1612 int af;
1613
1614 if (Ustrchr(ipa->address, ':') != NULL)
1615 {
1616 af = AF_INET6;
1617 wildcard = ipa->address[1] == 0;
1618 }
1619 else
1620 {
1621 af = AF_INET;
1622 wildcard = ipa->address[0] == 0;
1623 }
1624
96f5fe4c 1625 if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0)
059ec3d9
PH
1626 {
1627 if (check_special_case(0, addresses, ipa, FALSE))
1628 {
1629 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1630 "listening (%s): will use IPv4", strerror(errno));
1631 goto SKIP_SOCKET;
1632 }
1633 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1634 (af == AF_INET6)? '6' : '4', strerror(errno));
1635 }
1636
1637 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1638 available. Just log failure (can get protocol not available, just like
1639 socket creation can). */
1640
b891534f 1641#ifdef IPV6_V6ONLY
059ec3d9 1642 if (af == AF_INET6 && wildcard &&
5903c6ff 1643 setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, CS (&on),
059ec3d9
PH
1644 sizeof(on)) < 0)
1645 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1646 "socket failed (%s): carrying on without it", strerror(errno));
b891534f 1647#endif /* IPV6_V6ONLY */
059ec3d9
PH
1648
1649 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1650 is being handled. Without this, a connection will prevent reuse of the
1651 smtp port for listening. */
1652
1653 if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR,
5903c6ff 1654 US (&on), sizeof(on)) < 0)
059ec3d9
PH
1655 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1656 "failed when starting daemon: %s", strerror(errno));
1657
1658 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1659 disable this because it breaks some broken clients. */
1660
1661 if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY,
5903c6ff 1662 US (&on), sizeof(on));
059ec3d9
PH
1663
1664 /* Now bind the socket to the required port; if Exim is being restarted
1665 it may not always be possible to bind immediately, even with SO_REUSEADDR
1666 set, so try 10 times, waiting between each try. After 10 failures, we give
1667 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1668 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1669 address for the same port, ignore the error on the grounds that we must be
1670 in a system where the IPv6 socket accepts both kinds of call. This is
1671 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1672 listen() stage instead. */
1673
6af7e591 1674#ifdef TCP_FASTOPEN
8768d548 1675 f.tcp_fastopen_ok = TRUE;
6af7e591 1676#endif
059ec3d9
PH
1677 for(;;)
1678 {
1679 uschar *msg, *addr;
1680 if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break;
1681 if (check_special_case(errno, addresses, ipa, TRUE))
1682 {
1683 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1684 "listen() success; EADDRINUSE ignored\n");
f1e894f3 1685 (void)close(listen_sockets[sk]);
059ec3d9
PH
1686 goto SKIP_SOCKET;
1687 }
1688 msg = US strerror(errno);
b891534f
JH
1689 addr = wildcard
1690 ? af == AF_INET6
1691 ? US"(any IPv6)"
1692 : US"(any IPv4)"
1693 : ipa->address;
4aee0225 1694 if (daemon_startup_retries <= 0)
059ec3d9
PH
1695 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1696 "socket bind() to port %d for address %s failed: %s: "
1697 "daemon abandoned", ipa->port, addr, msg);
1698 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
4aee0225
PH
1699 "failed: %s: waiting %s before trying again (%d more %s)",
1700 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1701 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1702 daemon_startup_retries--;
1703 sleep(daemon_startup_sleep);
059ec3d9
PH
1704 }
1705
1706 DEBUG(D_any)
059ec3d9
PH
1707 if (wildcard)
1708 debug_printf("listening on all interfaces (IPv%c) port %d\n",
fb05276a 1709 af == AF_INET6 ? '6' : '4', ipa->port);
059ec3d9
PH
1710 else
1711 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
fb05276a 1712
b536a578 1713#if defined(TCP_FASTOPEN) && !defined(__APPLE__)
590faf89
JH
1714 if ( f.tcp_fastopen_ok
1715 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
4670e9d3 1716 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
6af7e591 1717 {
a23ff3b4 1718 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
8768d548 1719 f.tcp_fastopen_ok = FALSE;
6af7e591 1720 }
fb05276a 1721#endif
059ec3d9
PH
1722
1723 /* Start listening on the bound socket, establishing the maximum backlog of
1724 connections that is allowed. On success, continue to the next address. */
1725
b536a578
JH
1726 if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0)
1727 {
1728#if defined(TCP_FASTOPEN) && defined(__APPLE__)
1729 if ( f.tcp_fastopen_ok
1730 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1731 &on, sizeof(on)))
1732 {
1733 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1734 f.tcp_fastopen_ok = FALSE;
1735 }
1736#endif
1737 continue;
1738 }
059ec3d9
PH
1739
1740 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1741 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1742 and there was a previous successful IPv6 wildcard listen on the same port,
1743 we want to ignore the error on the grounds that we must be in a system
1744 where the IPv6 socket accepts both kinds of call. */
1745
1746 if (!check_special_case(errno, addresses, ipa, TRUE))
1747 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
fb05276a
JH
1748 wildcard
1749 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
059ec3d9
PH
1750 strerror(errno));
1751
1752 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1753 "listen() success; EADDRINUSE ignored\n");
f1e894f3 1754 (void)close(listen_sockets[sk]);
059ec3d9
PH
1755
1756 /* Come here if there has been a problem with the socket which we
1757 are going to ignore. We remove the address from the chain, and back up the
1758 counts. */
1759
b891534f 1760 SKIP_SOCKET:
059ec3d9
PH
1761 sk--; /* Back up the count */
1762 listen_socket_count--; /* Reduce the total */
1763 if (ipa == addresses) addresses = ipa->next; else
1764 {
1765 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1766 ipa2->next = ipa->next;
1767 ipa = ipa2;
1768 }
1769 } /* End of bind/listen loop for each address */
1770 } /* End of setup for listening */
1771
1772
1773/* If we are not listening, we want to write a pid file only if -oP was
1774explicitly given. */
1775
b891534f
JH
1776else if (!override_pid_file_path)
1777 write_pid = FALSE;
059ec3d9
PH
1778
1779/* Write the pid to a known file for assistance in identification, if required.
1780We do this before giving up root privilege, because on some systems it is
1781necessary to be root in order to write into the pid file directory. There's
1782nothing to stop multiple daemons running, as long as no more than one listens
1783on a given TCP/IP port on the same interface(s). However, in these
1784circumstances it gets far too complicated to mess with pid file names
1785automatically. Consequently, Exim 4 writes a pid file only
1786
1787 (a) When running in the test harness, or
1788 (b) When -bd is used and -oX is not used, or
1789 (c) When -oP is used to supply a path.
1790
1791The variable daemon_write_pid is used to control this. */
1792
8768d548 1793if (f.running_in_test_harness || write_pid)
059ec3d9
PH
1794 {
1795 FILE *f;
1796
01446a56 1797 set_pid_file_path();
b891534f 1798 if ((f = modefopen(pid_file_path, "wb", 0644)))
059ec3d9 1799 {
ff790e47 1800 (void)fprintf(f, "%d\n", (int)getpid());
ff790e47 1801 (void)fclose(f);
059ec3d9
PH
1802 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1803 }
1804 else
059ec3d9
PH
1805 DEBUG(D_any)
1806 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
1807 pid_file_path));
059ec3d9
PH
1808 }
1809
1810/* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1811
1812sighup_seen = FALSE;
1813signal(SIGHUP, sighup_handler);
1814
1815/* Give up root privilege at this point (assuming that exim_uid and exim_gid
1816are not root). The third argument controls the running of initgroups().
1817Normally we do this, in order to set up the groups for the Exim user. However,
1818if we are not root at this time - some odd installations run that way - we
1819cannot do this. */
1820
1821exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1822
ebeaf996
PH
1823/* Update the originator_xxx fields so that received messages as listed as
1824coming from Exim, not whoever started the daemon. */
1825
1826originator_uid = exim_uid;
1827originator_gid = exim_gid;
f3ebb786
JH
1828originator_login = (pw = getpwuid(exim_uid))
1829 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
ebeaf996 1830
059ec3d9
PH
1831/* Get somewhere to keep the list of queue-runner pids if we are keeping track
1832of them (and also if we are doing queue runs). */
1833
0cd5fd23 1834if (queue_interval > 0 && local_queue_run_max > 0)
059ec3d9 1835 {
f3ebb786 1836 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t), FALSE);
d7978c0f 1837 for (int i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
059ec3d9
PH
1838 }
1839
01446a56
JH
1840/* Set up the handler for termination of child processes, and the one
1841telling us to die. */
059ec3d9
PH
1842
1843sigchld_seen = FALSE;
7d468ab8 1844os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
059ec3d9 1845
01446a56
JH
1846sigterm_seen = FALSE;
1847os_non_restarting_signal(SIGTERM, main_sigterm_handler);
1848
059ec3d9
PH
1849/* If we are to run the queue periodically, pretend the alarm has just gone
1850off. This will cause the first queue-runner to get kicked off straight away. */
1851
1852sigalrm_seen = (queue_interval > 0);
1853
1854/* Log the start up of a daemon - at least one of listening or queue running
1855must be set up. */
1856
8768d548 1857if (f.inetd_wait_mode)
9ee44efb
PP
1858 {
1859 uschar *p = big_buffer;
1860
1861 if (inetd_wait_timeout >= 0)
1862 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
1863 else
1864 sprintf(CS p, "with no wait timeout");
1865
1866 log_write(0, LOG_MAIN,
1867 "exim %s daemon started: pid=%d, launched with listening socket, %s",
1868 version_string, getpid(), big_buffer);
2f21487f 1869 set_process_info("daemon(%s): pre-listening socket", version_string);
9ee44efb
PP
1870
1871 /* set up the timeout logic */
ff966302 1872 sigalrm_seen = TRUE;
9ee44efb
PP
1873 }
1874
8768d548 1875else if (f.daemon_listen)
059ec3d9 1876 {
059ec3d9
PH
1877 int smtp_ports = 0;
1878 int smtps_ports = 0;
254f38d1
JH
1879 ip_address_item * ipa;
1880 uschar * p;
e37f8a84
JH
1881 uschar * qinfo = queue_interval > 0
1882 ? string_sprintf("-q%s", readconf_printtime(queue_interval))
1883 : US"no queue runs";
059ec3d9
PH
1884
1885 /* Build a list of listening addresses in big_buffer, but limit it to 10
1886 items. The style is for backwards compatibility.
1887
1888 It is now possible to have some ports listening for SMTPS (the old,
1889 deprecated protocol that starts TLS without using STARTTLS), and others
1890 listening for standard SMTP. Keep their listings separate. */
1891
254f38d1 1892 for (int j = 0, i; j < 2; j++)
059ec3d9 1893 {
e37f8a84 1894 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
b891534f
JH
1895 {
1896 /* First time round, look for SMTP ports; second time round, look for
254f38d1 1897 SMTPS ports. Build IP+port strings. */
b891534f
JH
1898
1899 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1900 {
1901 if (j == 0)
254f38d1 1902 smtp_ports++;
b891534f 1903 else
254f38d1 1904 smtps_ports++;
b891534f
JH
1905
1906 /* Now the information about the port (and sometimes interface) */
1907
1908 if (ipa->address[0] == ':' && ipa->address[1] == 0)
e4d0fc93 1909 { /* v6 wildcard */
b891534f
JH
1910 if (ipa->next && ipa->next->address[0] == 0 &&
1911 ipa->next->port == ipa->port)
1912 {
254f38d1
JH
1913 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
1914 (ipa = ipa->next)->log = NULL;
b891534f
JH
1915 }
1916 else if (ipa->v6_include_v4)
254f38d1 1917 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
b891534f 1918 else
254f38d1 1919 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
b891534f 1920 }
e4d0fc93 1921 else if (ipa->address[0] == 0) /* v4 wildcard */
254f38d1 1922 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
e4d0fc93 1923 else /* check for previously-seen IP */
b891534f 1924 {
254f38d1 1925 ip_address_item * i2;
e4d0fc93
JH
1926 for (i2 = addresses; i2 != ipa; i2 = i2->next)
1927 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
1928 && Ustrcmp(ipa->address, i2->address) == 0
1929 )
1930 { /* found; append port to list */
254f38d1
JH
1931 for (p = i2->log; *p; ) p++; /* end of existing string */
1932 if (*--p == '}') *p = '\0'; /* drop EOL */
1933 while (isdigit(*--p)) ; /* char before port */
1934
1935 i2->log = *p == ':' /* no list yet? */
1936 ? string_sprintf("%.*s{%s,%d}",
1937 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
1938 : string_sprintf("%s,%d}", i2->log, ipa->port);
1939 ipa->log = NULL;
e4d0fc93
JH
1940 break;
1941 }
1942 if (i2 == ipa) /* first-time IP */
254f38d1 1943 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
b891534f 1944 }
b891534f
JH
1945 }
1946 }
254f38d1 1947 }
059ec3d9 1948
254f38d1
JH
1949 p = big_buffer;
1950 for (int j = 0, i; j < 2; j++)
1951 {
1952 /* First time round, look for SMTP ports; second time round, look for
1953 SMTPS ports. For the first one of each, insert leading text. */
1954
1955 if (j == 0)
059ec3d9 1956 {
254f38d1
JH
1957 if (smtp_ports > 0)
1958 p += sprintf(CS p, "SMTP on");
059ec3d9 1959 }
254f38d1
JH
1960 else
1961 if (smtps_ports > 0)
1962 p += sprintf(CS p, "%sSMTPS on",
1963 smtp_ports == 0 ? "" : " and for ");
1964
1965 /* Now the information about the port (and sometimes interface) */
1966
1967 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
1968 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1969 if (ipa->log)
1970 p += sprintf(CS p, "%s", ipa->log);
1971
1972 if (ipa)
1973 p += sprintf(CS p, " ...");
059ec3d9
PH
1974 }
1975
1976 log_write(0, LOG_MAIN,
1977 "exim %s daemon started: pid=%d, %s, listening for %s",
1978 version_string, getpid(), qinfo, big_buffer);
44915474
JH
1979 set_process_info("daemon(%s): %s, listening for %s",
1980 version_string, qinfo, big_buffer);
059ec3d9
PH
1981 }
1982
1983else
1984 {
44915474
JH
1985 uschar * s = *queue_name
1986 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
1987 : string_sprintf("-q%s", readconf_printtime(queue_interval));
059ec3d9 1988 log_write(0, LOG_MAIN,
44915474
JH
1989 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
1990 version_string, getpid(), s);
1991 set_process_info("daemon(%s): %s, not listening", version_string, s);
059ec3d9
PH
1992 }
1993
476be7e2
JH
1994/* Do any work it might be useful to amortize over our children
1995(eg: compile regex) */
1996
476be7e2 1997dns_pattern_init();
d85cdeb5
JH
1998smtp_deliver_init(); /* Used for callouts */
1999
2000#ifndef DISABLE_DKIM
2001 {
2002# ifdef MEASURE_TIMING
2003 struct timeval t0;
2004 gettimeofday(&t0, NULL);
2005# endif
2006 dkim_exim_init();
2007# ifdef MEASURE_TIMING
2008 report_time_since(&t0, US"dkim_exim_init (delta)");
2009# endif
2010 }
2011#endif
476be7e2
JH
2012
2013#ifdef WITH_CONTENT_SCAN
2014malware_init();
2015#endif
73ec116f
JH
2016#ifdef SUPPORT_SPF
2017spf_init();
2018#endif
059ec3d9
PH
2019
2020/* Close the log so it can be renamed and moved. In the few cases below where
2021this long-running process writes to the log (always exceptional conditions), it
2022closes the log afterwards, for the same reason. */
2023
2024log_close_all();
2025
2026DEBUG(D_any) debug_print_ids(US"daemon running with");
2027
2028/* Any messages accepted via this route are going to be SMTP. */
2029
2030smtp_input = TRUE;
2031
9f01e50d
JH
2032#ifdef MEASURE_TIMING
2033report_time_since(&timestamp_startup, US"daemon loop start"); /* testcase 0022 */
2034#endif
2035
059ec3d9
PH
2036/* Enter the never-ending loop... */
2037
2038for (;;)
2039 {
2040 #if HAVE_IPV6
2041 struct sockaddr_in6 accepted;
2042 #else
2043 struct sockaddr_in accepted;
2044 #endif
2045
cf73943b 2046 EXIM_SOCKLEN_T len;
059ec3d9
PH
2047 pid_t pid;
2048
01446a56
JH
2049 if (sigterm_seen)
2050 daemon_die(); /* Does not return */
2051
059ec3d9 2052 /* This code is placed first in the loop, so that it gets obeyed at the
9ee44efb
PP
2053 start, before the first wait, for the queue-runner case, so that the first
2054 one can be started immediately.
2055
2056 The other option is that we have an inetd wait timeout specified to -bw. */
059ec3d9
PH
2057
2058 if (sigalrm_seen)
2059 {
9ee44efb
PP
2060 if (inetd_wait_timeout > 0)
2061 {
2062 time_t resignal_interval = inetd_wait_timeout;
2063
2064 if (last_connection_time == (time_t)0)
2065 {
2066 DEBUG(D_any)
2067 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
2068 }
2069 else
2070 {
2071 time_t now = time(NULL);
2072 if (now == (time_t)-1)
2073 {
2074 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
2075 }
2076 else
2077 {
2078 if ((now - last_connection_time) >= inetd_wait_timeout)
2079 {
2080 DEBUG(D_any)
2081 debug_printf("inetd wait timeout %d expired, ending daemon\n",
2082 inetd_wait_timeout);
2083 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
2084 version_string);
2085 exit(EXIT_SUCCESS);
2086 }
2087 else
2088 {
2089 resignal_interval -= (now - last_connection_time);
2090 }
2091 }
2092 }
059ec3d9 2093
9ee44efb 2094 sigalrm_seen = FALSE;
c2a1bba0 2095 ALARM(resignal_interval);
9ee44efb 2096 }
059ec3d9 2097
9ee44efb 2098 else
059ec3d9 2099 {
ff966302
JH
2100 DEBUG(D_any) debug_printf("%s received\n",
2101#ifdef EXPERIMENTAL_QUEUE_RAMP
2102 *queuerun_msgid ? "qrun notification" :
2103#endif
2104 "SIGALRM");
8e669ac1 2105
9ee44efb
PP
2106 /* Do a full queue run in a child process, if required, unless we already
2107 have enough queue runners on the go. If we are not running as root, a
2108 re-exec is required. */
059ec3d9 2109
9ee44efb 2110 if (queue_interval > 0 &&
0cd5fd23 2111 (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
9ee44efb
PP
2112 {
2113 if ((pid = fork()) == 0)
2114 {
9ee44efb
PP
2115 DEBUG(D_any) debug_printf("Starting queue-runner: pid %d\n",
2116 (int)getpid());
8e669ac1 2117
9ee44efb
PP
2118 /* Disable debugging if it's required only for the daemon process. We
2119 leave the above message, because it ties up with the "child ended"
2120 debugging messages. */
059ec3d9 2121
8768d548 2122 if (f.debug_daemon) debug_selector = 0;
059ec3d9 2123
9ee44efb 2124 /* Close any open listening sockets in the child */
059ec3d9 2125
ff966302
JH
2126 if (daemon_notifier_fd >= 0)
2127 (void) close(daemon_notifier_fd);
d7978c0f 2128 for (int sk = 0; sk < listen_socket_count; sk++)
ff966302 2129 (void) close(listen_sockets[sk]);
059ec3d9 2130
9ee44efb 2131 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
059ec3d9 2132
9ee44efb
PP
2133 signal(SIGHUP, SIG_DFL);
2134 signal(SIGCHLD, SIG_DFL);
01446a56 2135 signal(SIGTERM, SIG_DFL);
059ec3d9 2136
9ee44efb
PP
2137 /* Re-exec if privilege has been given up, unless deliver_drop_
2138 privilege is set. Reset SIGALRM before exec(). */
4fbcfc2e 2139
9ee44efb 2140 if (geteuid() != root_uid && !deliver_drop_privilege)
4fbcfc2e 2141 {
9ee44efb
PP
2142 uschar opt[8];
2143 uschar *p = opt;
ff966302 2144 uschar *extra[7];
9ee44efb
PP
2145 int extracount = 1;
2146
2147 signal(SIGALRM, SIG_DFL);
2148 *p++ = '-';
2149 *p++ = 'q';
ff966302
JH
2150 if ( f.queue_2stage
2151#ifdef EXPERIMENTAL_QUEUE_RAMP
2152 && !*queuerun_msgid
2153#endif
2154 ) *p++ = 'q';
8768d548
JH
2155 if (f.queue_run_first_delivery) *p++ = 'i';
2156 if (f.queue_run_force) *p++ = 'f';
2157 if (f.deliver_force_thaw) *p++ = 'f';
2158 if (f.queue_run_local) *p++ = 'l';
9ee44efb 2159 *p = 0;
3f008c60 2160 extra[0] = *queue_name
e37f8a84 2161 ? string_sprintf("%sG%s", opt, queue_name) : opt;
9ee44efb 2162
ff966302
JH
2163#ifdef EXPERIMENTAL_QUEUE_RAMP
2164 if (*queuerun_msgid)
2165 {
2166 extra[extracount++] = queuerun_msgid; /* Trigger only the */
2167 extra[extracount++] = queuerun_msgid; /* one message */
2168 }
2169#endif
2170
9ee44efb
PP
2171 /* If -R or -S were on the original command line, ensure they get
2172 passed on. */
2173
e37f8a84 2174 if (deliver_selectstring)
9ee44efb 2175 {
8768d548 2176 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
9ee44efb
PP
2177 extra[extracount++] = deliver_selectstring;
2178 }
2179
e37f8a84 2180 if (deliver_selectstring_sender)
9ee44efb 2181 {
8768d548 2182 extra[extracount++] = f.deliver_selectstring_sender_regex
e37f8a84 2183 ? US"-Sr" : US"-S";
9ee44efb
PP
2184 extra[extracount++] = deliver_selectstring_sender;
2185 }
2186
2187 /* Overlay this process with a new execution. */
2188
ff966302
JH
2189 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
2190 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
9ee44efb
PP
2191
2192 /* Control never returns here. */
4fbcfc2e
PH
2193 }
2194
9ee44efb 2195 /* No need to re-exec; SIGALRM remains set to the default handler */
059ec3d9 2196
ff966302
JH
2197#ifdef EXPERIMENTAL_QUEUE_RAMP
2198 if (*queuerun_msgid)
2199 {
2200 f.queue_2stage = FALSE;
2201 queue_run(queuerun_msgid, queuerun_msgid, FALSE);
2202 }
2203 else
2204#endif
2205 queue_run(NULL, NULL, FALSE);
f3ebb786 2206 exim_underbar_exit(EXIT_SUCCESS);
059ec3d9
PH
2207 }
2208
9ee44efb 2209 if (pid < 0)
059ec3d9 2210 {
9ee44efb
PP
2211 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
2212 "process failed: %s", strerror(errno));
2213 log_close_all();
2214 }
2215 else
2216 {
d7978c0f 2217 for (int i = 0; i < local_queue_run_max; ++i)
9ee44efb
PP
2218 if (queue_pid_slots[i] <= 0)
2219 {
2220 queue_pid_slots[i] = pid;
2221 queue_run_count++;
2222 break;
2223 }
9ee44efb 2224 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
d7978c0f 2225 queue_run_count, queue_run_count == 1 ? "" : "es");
059ec3d9 2226 }
059ec3d9 2227 }
059ec3d9 2228
9ee44efb 2229 /* Reset the alarm clock */
059ec3d9 2230
9ee44efb 2231 sigalrm_seen = FALSE;
ff966302
JH
2232#ifdef EXPERIMENTAL_QUEUE_RAMP
2233 if (*queuerun_msgid)
2234 *queuerun_msgid = 0;
2235 else
2236#endif
2237 ALARM(queue_interval);
9ee44efb
PP
2238 }
2239
2240 } /* sigalrm_seen */
059ec3d9
PH
2241
2242
2243 /* Sleep till a connection happens if listening, and handle the connection if
2244 that is why we woke up. The FreeBSD operating system requires the use of
2245 select() before accept() because the latter function is not interrupted by
2246 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2247 OS do notice signals in accept() but it does no harm to have the select()
2248 in for all of them - and it won't then be a lurking problem for ports to
2249 new OS. In fact, the later addition of listening on specific interfaces only
2250 requires this way of working anyway. */
2251
8768d548 2252 if (f.daemon_listen)
059ec3d9 2253 {
d7978c0f 2254 int lcount, select_errno;
059ec3d9
PH
2255 int max_socket = 0;
2256 BOOL select_failed = FALSE;
2257 fd_set select_listen;
2258
2259 FD_ZERO(&select_listen);
ff966302
JH
2260 if (daemon_notifier_fd >= 0)
2261 FD_SET(daemon_notifier_fd, &select_listen);
d7978c0f 2262 for (int sk = 0; sk < listen_socket_count; sk++)
059ec3d9
PH
2263 {
2264 FD_SET(listen_sockets[sk], &select_listen);
2265 if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk];
2266 }
2267
2268 DEBUG(D_any) debug_printf("Listening...\n");
8e669ac1
PH
2269
2270 /* In rare cases we may have had a SIGCHLD signal in the time between
2271 setting the handler (below) and getting back here. If so, pretend that the
7d468ab8 2272 select() was interrupted so that we reap the child. This might still leave
8e669ac1 2273 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
7d468ab8
PH
2274 only to do the reaping more quickly, it shouldn't result in anything other
2275 than a delay until something else causes a wake-up. */
2276
2277 if (sigchld_seen)
2278 {
2279 lcount = -1;
8e669ac1 2280 errno = EINTR;
7d468ab8
PH
2281 }
2282 else
7d468ab8
PH
2283 lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen,
2284 NULL, NULL, NULL);
059ec3d9 2285
7d468ab8 2286 if (lcount < 0)
059ec3d9
PH
2287 {
2288 select_failed = TRUE;
2289 lcount = 1;
2290 }
8e669ac1
PH
2291
2292 /* Clean up any subprocesses that may have terminated. We need to do this
2293 here so that smtp_accept_max_per_host works when a connection to that host
2294 has completed, and we are about to accept a new one. When this code was
2295 later in the sequence, a new connection could be rejected, even though an
2296 old one had just finished. Preserve the errno from any select() failure for
bb6e88ff 2297 the use of the common select/accept error processing below. */
8e669ac1 2298
bb6e88ff
PH
2299 select_errno = errno;
2300 handle_ending_processes();
8e669ac1
PH
2301 errno = select_errno;
2302
01603eec 2303#ifndef DISABLE_TLS
b10c87b3
JH
2304 /* Create or rotate any required keys */
2305 tls_daemon_init();
2306#endif
2307
059ec3d9 2308 /* Loop for all the sockets that are currently ready to go. If select
7d468ab8
PH
2309 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2310 to use the common error code for select/accept below. */
059ec3d9
PH
2311
2312 while (lcount-- > 0)
2313 {
2314 int accept_socket = -1;
6851a9c5 2315
059ec3d9 2316 if (!select_failed)
ff966302 2317 {
ff966302
JH
2318 if ( daemon_notifier_fd >= 0
2319 && FD_ISSET(daemon_notifier_fd, &select_listen))
2320 {
2321 FD_CLR(daemon_notifier_fd, &select_listen);
2322 sigalrm_seen = daemon_notification();
2323 break; /* to top of daemon loop */
2324 }
d7978c0f 2325 for (int sk = 0; sk < listen_socket_count; sk++)
059ec3d9
PH
2326 if (FD_ISSET(listen_sockets[sk], &select_listen))
2327 {
cf73943b 2328 len = sizeof(accepted);
059ec3d9
PH
2329 accept_socket = accept(listen_sockets[sk],
2330 (struct sockaddr *)&accepted, &len);
2331 FD_CLR(listen_sockets[sk], &select_listen);
2332 break;
2333 }
ff966302 2334 }
059ec3d9
PH
2335
2336 /* If select or accept has failed and this was not caused by an
2337 interruption, log the incident and try again. With asymmetric TCP/IP
2338 routing errors such as "No route to network" have been seen here. Also
2339 "connection reset by peer" has been seen. These cannot be classed as
2340 disastrous errors, but they could fill up a lot of log. The code in smail
2341 crashes the daemon after 10 successive failures of accept, on the grounds
2342 that some OS fail continuously. Exim originally followed suit, but this
2343 appears to have caused problems. Now it just keeps going, but instead of
2344 logging each error, it batches them up when they are continuous. */
2345
2346 if (accept_socket < 0 && errno != EINTR)
2347 {
2348 if (accept_retry_count == 0)
2349 {
2350 accept_retry_errno = errno;
2351 accept_retry_select_failed = select_failed;
2352 }
2353 else
2354 {
2355 if (errno != accept_retry_errno ||
2356 select_failed != accept_retry_select_failed ||
2357 accept_retry_count >= 50)
2358 {
2359 log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0),
2360 "%d %s() failure%s: %s",
2361 accept_retry_count,
2362 accept_retry_select_failed? "select" : "accept",
2363 (accept_retry_count == 1)? "" : "s",
2364 strerror(accept_retry_errno));
2365 log_close_all();
2366 accept_retry_count = 0;
2367 accept_retry_errno = errno;
2368 accept_retry_select_failed = select_failed;
2369 }
2370 }
2371 accept_retry_count++;
2372 }
2373
2374 else
2375 {
2376 if (accept_retry_count > 0)
2377 {
2378 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2379 accept_retry_count,
2380 accept_retry_select_failed? "select" : "accept",
2381 (accept_retry_count == 1)? "" : "s",
2382 strerror(accept_retry_errno));
2383 log_close_all();
2384 accept_retry_count = 0;
2385 }
2386 }
2387
2388 /* If select/accept succeeded, deal with the connection. */
2389
2390 if (accept_socket >= 0)
9ee44efb
PP
2391 {
2392 if (inetd_wait_timeout)
2393 last_connection_time = time(NULL);
059ec3d9
PH
2394 handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,
2395 (struct sockaddr *)&accepted);
9ee44efb 2396 }
059ec3d9
PH
2397 }
2398 }
2399
2400 /* If not listening, then just sleep for the queue interval. If we woke
2401 up early the last time for some other signal, it won't matter because
2402 the alarm signal will wake at the right time. This code originally used
2403 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2404 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2405 select() can be used as an interruptible sleep() on all versions of Unix. */
2406
2407 else
2408 {
2409 struct timeval tv;
2410 tv.tv_sec = queue_interval;
2411 tv.tv_usec = 0;
2412 select(0, NULL, NULL, NULL, &tv);
8e669ac1 2413 handle_ending_processes();
059ec3d9
PH
2414 }
2415
2416 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2417 for itself, because it isn't doing the waiting itself. */
2418
2419 if (sigchld_seen)
2420 {
2421 sigchld_seen = FALSE;
7d468ab8 2422 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
059ec3d9
PH
2423 }
2424
2425 /* Handle being woken by SIGHUP. We know at this point that the result
2426 of accept() has been dealt with, so we can re-exec exim safely, first
2427 closing the listening sockets so that they can be reused. Cancel any pending
2428 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2429 that another HUP in quick succession doesn't clobber the new daemon before it
2430 gets going. All log files get closed by the close-on-exec flag; however, if
2431 the exec fails, we need to close the logs. */
2432
2433 if (sighup_seen)
2434 {
059ec3d9
PH
2435 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2436 getpid());
d7978c0f 2437 for (int sk = 0; sk < listen_socket_count; sk++)
f1e894f3 2438 (void)close(listen_sockets[sk]);
c2a1bba0 2439 ALARM_CLR(0);
059ec3d9
PH
2440 signal(SIGHUP, SIG_IGN);
2441 sighup_argv[0] = exim_path;
2442 exim_nullstd();
2443 execv(CS exim_path, (char *const *)sighup_argv);
2444 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2445 getpid(), exim_path, strerror(errno));
2446 log_close_all();
2447 }
2448
2449 } /* End of main loop */
2450
2451/* Control never reaches here */
2452}
2453
071c51f7
JH
2454/* vi: aw ai sw=2
2455*/
059ec3d9 2456/* End of exim_daemon.c */