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