debug 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/*************************************************
8cfc4d82
JH
130*************************************************/
131
132static void
133close_daemon_sockets(int daemon_notifier_fd,
134 int * listen_sockets, int listen_socket_count)
135{
136if (daemon_notifier_fd >= 0) (void) close(daemon_notifier_fd);
137for (int i = 0; i < listen_socket_count; i++) (void) close(listen_sockets[i]);
138}
139
140
141/*************************************************
059ec3d9
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142* Handle a connected SMTP call *
143*************************************************/
144
145/* This function is called when an SMTP connection has been accepted.
146If there are too many, give an error message and close down. Otherwise
147spin off a sub-process to handle the call. The list of listening sockets
148is required so that they can be closed in the sub-process. Take care not to
149leak store in this process - reset the stacking pool at the end.
150
151Arguments:
152 listen_sockets sockets which are listening for incoming calls
153 listen_socket_count count of listening sockets
154 accept_socket socket of the current accepted call
155 accepted socket information about the current call
156
157Returns: nothing
158*/
159
160static void
161handle_smtp_call(int *listen_sockets, int listen_socket_count,
162 int accept_socket, struct sockaddr *accepted)
163{
164pid_t pid;
165union sockaddr_46 interface_sockaddr;
36a3b041 166EXIM_SOCKLEN_T ifsize = sizeof(interface_sockaddr);
059ec3d9
PH
167int dup_accept_socket = -1;
168int max_for_this_host = 0;
6c6d6e48 169int save_log_selector = *log_selector;
b2bcdd35 170gstring * whofrom;
059ec3d9 171
f3ebb786 172rmark reset_point = store_mark();
059ec3d9
PH
173
174/* Make the address available in ASCII representation, and also fish out
175the remote port. */
176
177sender_host_address = host_ntoa(-1, accepted, NULL, &sender_host_port);
178DEBUG(D_any) debug_printf("Connection request from %s port %d\n",
179 sender_host_address, sender_host_port);
180
181/* Set up the output stream, check the socket has duplicated, and set up the
182input stream. These operations fail only the exceptional circumstances. Note
183that never_error() won't use smtp_out if it is NULL. */
184
f5d25c2b 185if (!(smtp_out = fdopen(accept_socket, "wb")))
059ec3d9
PH
186 {
187 never_error(US"daemon: fdopen() for smtp_out failed", US"", errno);
188 goto ERROR_RETURN;
189 }
190
f5d25c2b 191if ((dup_accept_socket = dup(accept_socket)) < 0)
059ec3d9
PH
192 {
193 never_error(US"daemon: couldn't dup socket descriptor",
194 US"Connection setup failed", errno);
195 goto ERROR_RETURN;
196 }
197
f5d25c2b 198if (!(smtp_in = fdopen(dup_accept_socket, "rb")))
059ec3d9
PH
199 {
200 never_error(US"daemon: fdopen() for smtp_in failed",
201 US"Connection setup failed", errno);
202 goto ERROR_RETURN;
203 }
204
520de300
PH
205/* Get the data for the local interface address. Panic for most errors, but
206"connection reset by peer" just means the connection went away. */
059ec3d9
PH
207
208if (getsockname(accept_socket, (struct sockaddr *)(&interface_sockaddr),
209 &ifsize) < 0)
210 {
520de300
PH
211 log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC),
212 "getsockname() failed: %s", strerror(errno));
925ac8e4 213 smtp_printf("421 Local problem: getsockname() failed; please try again later\r\n", FALSE);
059ec3d9
PH
214 goto ERROR_RETURN;
215 }
216
217interface_address = host_ntoa(-1, &interface_sockaddr, NULL, &interface_port);
218DEBUG(D_interface) debug_printf("interface address=%s port=%d\n",
219 interface_address, interface_port);
220
221/* Build a string identifying the remote host and, if requested, the port and
222the local interface data. This is for logging; at the end of this function the
223memory is reclaimed. */
224
b2bcdd35 225whofrom = string_append(NULL, 3, "[", sender_host_address, "]");
059ec3d9 226
6c6d6e48 227if (LOGGING(incoming_port))
52f12a7c 228 whofrom = string_fmt_append(whofrom, ":%d", sender_host_port);
059ec3d9 229
6c6d6e48 230if (LOGGING(incoming_interface))
52f12a7c
JH
231 whofrom = string_fmt_append(whofrom, " I=[%s]:%d",
232 interface_address, interface_port);
059ec3d9 233
acec9514 234(void) string_from_gstring(whofrom); /* Terminate the newly-built string */
059ec3d9
PH
235
236/* Check maximum number of connections. We do not check for reserved
237connections or unacceptable hosts here. That is done in the subprocess because
238it might take some time. */
239
240if (smtp_accept_max > 0 && smtp_accept_count >= smtp_accept_max)
241 {
242 DEBUG(D_any) debug_printf("rejecting SMTP connection: count=%d max=%d\n",
243 smtp_accept_count, smtp_accept_max);
244 smtp_printf("421 Too many concurrent SMTP connections; "
925ac8e4 245 "please try again later.\r\n", FALSE);
059ec3d9
PH
246 log_write(L_connection_reject,
247 LOG_MAIN, "Connection from %s refused: too many connections",
acec9514 248 whofrom->s);
059ec3d9
PH
249 goto ERROR_RETURN;
250 }
251
252/* If a load limit above which only reserved hosts are acceptable is defined,
253get the load average here, and if there are in fact no reserved hosts, do
254the test right away (saves a fork). If there are hosts, do the check in the
255subprocess because it might take time. */
256
257if (smtp_load_reserve >= 0)
258 {
8669f003 259 load_average = OS_GETLOADAVG();
059ec3d9
PH
260 if (smtp_reserve_hosts == NULL && load_average > smtp_load_reserve)
261 {
262 DEBUG(D_any) debug_printf("rejecting SMTP connection: load average = %.2f\n",
263 (double)load_average/1000.0);
925ac8e4 264 smtp_printf("421 Too much load; please try again later.\r\n", FALSE);
059ec3d9
PH
265 log_write(L_connection_reject,
266 LOG_MAIN, "Connection from %s refused: load average = %.2f",
acec9514 267 whofrom->s, (double)load_average/1000.0);
059ec3d9
PH
268 goto ERROR_RETURN;
269 }
270 }
271
272/* Check that one specific host (strictly, IP address) is not hogging
273resources. This is done here to prevent a denial of service attack by someone
274forcing you to fork lots of times before denying service. The value of
275smtp_accept_max_per_host is a string which is expanded. This makes it possible
276to provide host-specific limits according to $sender_host address, but because
277this is in the daemon mainline, only fast expansions (such as inline address
278checks) should be used. The documentation is full of warnings. */
279
280if (smtp_accept_max_per_host != NULL)
281 {
282 uschar *expanded = expand_string(smtp_accept_max_per_host);
283 if (expanded == NULL)
284 {
8768d548 285 if (!f.expand_string_forcedfail)
059ec3d9 286 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
acec9514 287 "failed for %s: %s", whofrom->s, expand_string_message);
059ec3d9
PH
288 }
289 /* For speed, interpret a decimal number inline here */
290 else
291 {
292 uschar *s = expanded;
293 while (isdigit(*s))
294 max_for_this_host = max_for_this_host * 10 + *s++ - '0';
295 if (*s != 0)
296 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
acec9514 297 "for %s contains non-digit: %s", whofrom->s, expanded);
059ec3d9
PH
298 }
299 }
300
301/* If we have fewer connections than max_for_this_host, we can skip the tedious
302per host_address checks. Note that at this stage smtp_accept_count contains the
303count of *other* connections, not including this one. */
304
305if ((max_for_this_host > 0) &&
306 (smtp_accept_count >= max_for_this_host))
307 {
059ec3d9
PH
308 int host_accept_count = 0;
309 int other_host_count = 0; /* keep a count of non matches to optimise */
310
d7978c0f 311 for (int i = 0; i < smtp_accept_max; ++i)
8cfd0f7b 312 if (smtp_slots[i].host_address)
059ec3d9
PH
313 {
314 if (Ustrcmp(sender_host_address, smtp_slots[i].host_address) == 0)
315 host_accept_count++;
316 else
317 other_host_count++;
318
319 /* Testing all these strings is expensive - see if we can drop out
320 early, either by hitting the target, or finding there are not enough
321 connections left to make the target. */
322
323 if ((host_accept_count >= max_for_this_host) ||
324 ((smtp_accept_count - other_host_count) < max_for_this_host))
325 break;
326 }
059ec3d9
PH
327
328 if (host_accept_count >= max_for_this_host)
329 {
330 DEBUG(D_any) debug_printf("rejecting SMTP connection: too many from this "
331 "IP address: count=%d max=%d\n",
332 host_accept_count, max_for_this_host);
333 smtp_printf("421 Too many concurrent SMTP connections "
925ac8e4 334 "from this IP address; please try again later.\r\n", FALSE);
059ec3d9
PH
335 log_write(L_connection_reject,
336 LOG_MAIN, "Connection from %s refused: too many connections "
acec9514 337 "from that IP address", whofrom->s);
059ec3d9
PH
338 goto ERROR_RETURN;
339 }
340 }
341
342/* OK, the connection count checks have been passed. Before we can fork the
343accepting process, we must first log the connection if requested. This logging
344used to happen in the subprocess, but doing that means that the value of
345smtp_accept_count can be out of step by the time it is logged. So we have to do
346the logging here and accept the performance cost. Note that smtp_accept_count
347hasn't yet been incremented to take account of this connection.
348
349In order to minimize the cost (because this is going to happen for every
350connection), do a preliminary selector test here. This saves ploughing through
351the generalized logging code each time when the selector is false. If the
352selector is set, check whether the host is on the list for logging. If not,
353arrange to unset the selector in the subprocess. */
354
6c6d6e48 355if (LOGGING(smtp_connection))
059ec3d9
PH
356 {
357 uschar *list = hosts_connection_nolog;
ce325893 358 memset(sender_host_cache, 0, sizeof(sender_host_cache));
059ec3d9 359 if (list != NULL && verify_check_host(&list) == OK)
6c6d6e48 360 save_log_selector &= ~L_smtp_connection;
059ec3d9
PH
361 else
362 log_write(L_smtp_connection, LOG_MAIN, "SMTP connection from %s "
acec9514 363 "(TCP/IP connection count = %d)", whofrom->s, smtp_accept_count + 1);
059ec3d9
PH
364 }
365
366/* Now we can fork the accepting process; do a lookup tidy, just in case any
367expansion above did a lookup. */
368
369search_tidyup();
8e9fdd63 370pid = exim_fork(US"daemon accept");
059ec3d9
PH
371
372/* Handle the child process */
373
374if (pid == 0)
375 {
376 int i;
377 int queue_only_reason = 0;
378 int old_pool = store_pool;
8e669ac1 379 int save_debug_selector = debug_selector;
059ec3d9 380 BOOL local_queue_only;
8669f003 381 BOOL session_local_queue_only;
059ec3d9
PH
382 #ifdef SA_NOCLDWAIT
383 struct sigaction act;
384 #endif
385
b01dd148
PH
386 smtp_accept_count++; /* So that it includes this process */
387
059ec3d9
PH
388 /* May have been modified for the subprocess */
389
6c6d6e48 390 *log_selector = save_log_selector;
059ec3d9
PH
391
392 /* Get the local interface address into permanent store */
393
394 store_pool = POOL_PERM;
395 interface_address = string_copy(interface_address);
396 store_pool = old_pool;
397
398 /* Check for a tls-on-connect port */
399
817d9f57 400 if (host_is_tls_on_connect_port(interface_port)) tls_in.on_connect = TRUE;
059ec3d9
PH
401
402 /* Expand smtp_active_hostname if required. We do not do this any earlier,
403 because it may depend on the local interface address (indeed, that is most
404 likely what it depends on.) */
405
406 smtp_active_hostname = primary_hostname;
ad7fc6eb 407 if (raw_active_hostname)
059ec3d9 408 {
ad7fc6eb
JH
409 uschar * nah = expand_string(raw_active_hostname);
410 if (!nah)
059ec3d9 411 {
8768d548 412 if (!f.expand_string_forcedfail)
059ec3d9
PH
413 {
414 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand \"%s\" "
415 "(smtp_active_hostname): %s", raw_active_hostname,
416 expand_string_message);
417 smtp_printf("421 Local configuration error; "
925ac8e4 418 "please try again later.\r\n", FALSE);
059ec3d9
PH
419 mac_smtp_fflush();
420 search_tidyup();
afd5e75f 421 exim_underbar_exit(EXIT_FAILURE, US"conn-accept");
059ec3d9
PH
422 }
423 }
ad7fc6eb 424 else if (*nah) smtp_active_hostname = nah;
059ec3d9
PH
425 }
426
427 /* Initialize the queueing flags */
428
429 queue_check_only();
8669f003 430 session_local_queue_only = queue_only;
059ec3d9
PH
431
432 /* Close the listening sockets, and set the SIGCHLD handler to SIG_IGN.
433 We also attempt to set things up so that children are automatically reaped,
434 but just in case this isn't available, there's a paranoid waitpid() in the
435 loop too (except for systems where we are sure it isn't needed). See the more
436 extensive comment before the reception loop in exim.c for a fuller
437 explanation of this logic. */
438
8cfc4d82 439 close_daemon_sockets(daemon_notifier_fd, listen_sockets, listen_socket_count);
059ec3d9 440
fa32850b
DW
441 /* Set FD_CLOEXEC on the SMTP socket. We don't want any rogue child processes
442 to be able to communicate with them, under any circumstances. */
443 (void)fcntl(accept_socket, F_SETFD,
444 fcntl(accept_socket, F_GETFD) | FD_CLOEXEC);
445 (void)fcntl(dup_accept_socket, F_SETFD,
446 fcntl(dup_accept_socket, F_GETFD) | FD_CLOEXEC);
447
059ec3d9
PH
448 #ifdef SA_NOCLDWAIT
449 act.sa_handler = SIG_IGN;
450 sigemptyset(&(act.sa_mask));
451 act.sa_flags = SA_NOCLDWAIT;
452 sigaction(SIGCHLD, &act, NULL);
453 #else
454 signal(SIGCHLD, SIG_IGN);
455 #endif
01446a56 456 signal(SIGTERM, SIG_DFL);
059ec3d9
PH
457
458 /* Attempt to get an id from the sending machine via the RFC 1413
459 protocol. We do this in the sub-process in order not to hold up the
460 main process if there is any delay. Then set up the fullhost information
8e669ac1
PH
461 in case there is no HELO/EHLO.
462
463 If debugging is enabled only for the daemon, we must turn if off while
464 finding the id, but turn it on again afterwards so that information about the
3d235903 465 incoming connection is output. */
8e669ac1 466
8768d548 467 if (f.debug_daemon) debug_selector = 0;
059ec3d9
PH
468 verify_get_ident(IDENT_PORT);
469 host_build_sender_fullhost();
8e669ac1 470 debug_selector = save_debug_selector;
059ec3d9
PH
471
472 DEBUG(D_any)
473 debug_printf("Process %d is handling incoming connection from %s\n",
474 (int)getpid(), sender_fullhost);
475
3d235903
PH
476 /* Now disable debugging permanently if it's required only for the daemon
477 process. */
478
8768d548 479 if (f.debug_daemon) debug_selector = 0;
3d235903 480
059ec3d9 481 /* If there are too many child processes for immediate delivery,
8669f003 482 set the session_local_queue_only flag, which is initialized from the
059ec3d9 483 configured value and may therefore already be TRUE. Leave logging
8669f003
PH
484 till later so it will have a message id attached. Note that there is no
485 possibility of re-calculating this per-message, because the value of
486 smtp_accept_count does not change in this subprocess. */
059ec3d9 487
b01dd148 488 if (smtp_accept_queue > 0 && smtp_accept_count > smtp_accept_queue)
059ec3d9 489 {
8669f003 490 session_local_queue_only = TRUE;
059ec3d9
PH
491 queue_only_reason = 1;
492 }
493
494 /* Handle the start of the SMTP session, then loop, accepting incoming
495 messages from the SMTP connection. The end will come at the QUIT command,
496 when smtp_setup_msg() returns 0. A break in the connection causes the
24796b8d
PH
497 process to die (see accept.c).
498
499 NOTE: We do *not* call smtp_log_no_mail() if smtp_start_session() fails,
500 because a log line has already been written for all its failure exists
501 (usually "connection refused: <reason>") and writing another one is
502 unnecessary clutter. */
059ec3d9
PH
503
504 if (!smtp_start_session())
505 {
506 mac_smtp_fflush();
507 search_tidyup();
afd5e75f 508 exim_underbar_exit(EXIT_SUCCESS, US"conn-smtp");
059ec3d9
PH
509 }
510
511 for (;;)
512 {
513 int rc;
514 message_id[0] = 0; /* Clear out any previous message_id */
f3ebb786 515 reset_point = store_mark(); /* Save current store high water point */
059ec3d9
PH
516
517 DEBUG(D_any)
518 debug_printf("Process %d is ready for new message\n", (int)getpid());
519
520 /* Smtp_setup_msg() returns 0 on QUIT or if the call is from an
521 unacceptable host or if an ACL "drop" command was triggered, -1 on
522 connection lost, and +1 on validly reaching DATA. Receive_msg() almost
523 always returns TRUE when smtp_input is true; just retry if no message was
524 accepted (can happen for invalid message parameters). However, it can yield
525 FALSE if the connection was forcibly dropped by the DATA ACL. */
526
527 if ((rc = smtp_setup_msg()) > 0)
528 {
529 BOOL ok = receive_msg(FALSE);
530 search_tidyup(); /* Close cached databases */
531 if (!ok) /* Connection was dropped */
532 {
57cc2785 533 cancel_cutthrough_connection(TRUE, US"receive dropped");
059ec3d9 534 mac_smtp_fflush();
b4ed4da0 535 smtp_log_no_mail(); /* Log no mail if configured */
afd5e75f 536 exim_underbar_exit(EXIT_SUCCESS, US"conn-receive");
059ec3d9
PH
537 }
538 if (message_id[0] == 0) continue; /* No message was accepted */
539 }
540 else
541 {
ad7fc6eb
JH
542 if (smtp_out)
543 {
d7978c0f 544 int fd = fileno(smtp_in);
ad7fc6eb
JH
545 uschar buf[128];
546
547 mac_smtp_fflush();
548 /* drain socket, for clean TCP FINs */
5ddc9771 549 if (fcntl(fd, F_SETFL, O_NONBLOCK) == 0)
d7978c0f 550 for(int i = 16; read(fd, buf, sizeof(buf)) > 0 && i > 0; ) i--;
ad7fc6eb 551 }
57cc2785 552 cancel_cutthrough_connection(TRUE, US"message setup dropped");
059ec3d9 553 search_tidyup();
b4ed4da0 554 smtp_log_no_mail(); /* Log no mail if configured */
60d10ce7
JH
555
556 /*XXX should we pause briefly, hoping that the client will be the
557 active TCP closer hence get the TCP_WAIT endpoint? */
558 DEBUG(D_receive) debug_printf("SMTP>>(close on process exit)\n");
afd5e75f 559 exim_underbar_exit(rc ? EXIT_FAILURE : EXIT_SUCCESS, US"conn-setup");
059ec3d9
PH
560 }
561
562 /* Show the recipients when debugging */
563
564 DEBUG(D_receive)
565 {
2c0f3ea1 566 if (sender_address)
059ec3d9 567 debug_printf("Sender: %s\n", sender_address);
2c0f3ea1 568 if (recipients_list)
059ec3d9
PH
569 {
570 debug_printf("Recipients:\n");
d7978c0f 571 for (int i = 0; i < recipients_count; i++)
059ec3d9
PH
572 debug_printf(" %s\n", recipients_list[i].address);
573 }
574 }
575
576 /* A message has been accepted. Clean up any previous delivery processes
577 that have completed and are defunct, on systems where they don't go away
578 by themselves (see comments when setting SIG_IGN above). On such systems
579 (if any) these delivery processes hang around after termination until
580 the next message is received. */
581
582 #ifndef SIG_IGN_WORKS
583 while (waitpid(-1, NULL, WNOHANG) > 0);
584 #endif
585
586 /* Reclaim up the store used in accepting this message */
587
e04bfa34
JH
588 {
589 int r = receive_messagecount;
8768d548 590 BOOL q = f.queue_only_policy;
e04bfa34 591 smtp_reset(reset_point);
f3ebb786 592 reset_point = NULL;
8768d548 593 f.queue_only_policy = q;
e04bfa34
JH
594 receive_messagecount = r;
595 }
059ec3d9
PH
596
597 /* If queue_only is set or if there are too many incoming connections in
8669f003
PH
598 existence, session_local_queue_only will be TRUE. If it is not, check
599 whether we have received too many messages in this session for immediate
600 delivery. */
601
602 if (!session_local_queue_only &&
603 smtp_accept_queue_per_connection > 0 &&
604 receive_messagecount > smtp_accept_queue_per_connection)
059ec3d9 605 {
8669f003
PH
606 session_local_queue_only = TRUE;
607 queue_only_reason = 2;
608 }
609
610 /* Initialize local_queue_only from session_local_queue_only. If it is not
611 true, and queue_only_load is set, check that the load average is below it.
612 If local_queue_only is set by this means, we also set if for the session if
613 queue_only_load_latch is true (the default). This means that, once set,
614 local_queue_only remains set for any subsequent messages on the same SMTP
615 connection. This is a deliberate choice; even though the load average may
616 fall, it doesn't seem right to deliver later messages on the same call when
617 not delivering earlier ones. However, the are special circumstances such as
618 very long-lived connections from scanning appliances where this is not the
619 best strategy. In such cases, queue_only_load_latch should be set false. */
620
f5d25c2b
JH
621 if ( !(local_queue_only = session_local_queue_only)
622 && queue_only_load >= 0
623 && (local_queue_only = (load_average = OS_GETLOADAVG()) > queue_only_load)
624 )
8669f003 625 {
f5d25c2b
JH
626 queue_only_reason = 3;
627 if (queue_only_load_latch) session_local_queue_only = TRUE;
059ec3d9
PH
628 }
629
630 /* Log the queueing here, when it will get a message id attached, but
631 not if queue_only is set (case 0). */
632
633 if (local_queue_only) switch(queue_only_reason)
634 {
f5d25c2b 635 case 1: log_write(L_delay_delivery,
059ec3d9
PH
636 LOG_MAIN, "no immediate delivery: too many connections "
637 "(%d, max %d)", smtp_accept_count, smtp_accept_queue);
f5d25c2b 638 break;
059ec3d9 639
f5d25c2b 640 case 2: log_write(L_delay_delivery,
059ec3d9
PH
641 LOG_MAIN, "no immediate delivery: more than %d messages "
642 "received in one connection", smtp_accept_queue_per_connection);
f5d25c2b 643 break;
059ec3d9 644
f5d25c2b 645 case 3: log_write(L_delay_delivery,
059ec3d9
PH
646 LOG_MAIN, "no immediate delivery: load average %.2f",
647 (double)load_average/1000.0);
f5d25c2b 648 break;
059ec3d9
PH
649 }
650
651 /* If a delivery attempt is required, spin off a new process to handle it.
652 If we are not root, we have to re-exec exim unless deliveries are being
653 done unprivileged. */
654
9438970c
JH
655 else if ( (!f.queue_only_policy || f.queue_smtp)
656 && !f.deliver_freeze)
059ec3d9
PH
657 {
658 pid_t dpid;
659
660 /* Before forking, ensure that the C output buffer is flushed. Otherwise
661 anything that it in it will get duplicated, leading to duplicate copies
662 of the pending output. */
663
664 mac_smtp_fflush();
665
4b01271f 666 if ((dpid = exim_fork(US"daemon-accept-delivery")) == 0)
059ec3d9 667 {
f1e894f3
PH
668 (void)fclose(smtp_in);
669 (void)fclose(smtp_out);
059ec3d9
PH
670
671 /* Don't ever molest the parent's SSL connection, but do clean up
672 the data structures if necessary. */
673
01603eec 674#ifndef DISABLE_TLS
74f1a423 675 tls_close(NULL, TLS_NO_SHUTDOWN);
57cc2785 676#endif
059ec3d9
PH
677
678 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
679
680 signal(SIGHUP, SIG_DFL);
681 signal(SIGCHLD, SIG_DFL);
01446a56 682 signal(SIGTERM, SIG_DFL);
059ec3d9
PH
683
684 if (geteuid() != root_uid && !deliver_drop_privilege)
685 {
686 signal(SIGALRM, SIG_DFL);
57cc2785 687 delivery_re_exec(CEE_EXEC_PANIC);
059ec3d9
PH
688 /* Control does not return here. */
689 }
690
691 /* No need to re-exec; SIGALRM remains set to the default handler */
692
57cc2785 693 (void) deliver_message(message_id, FALSE, FALSE);
059ec3d9 694 search_tidyup();
afd5e75f 695 exim_underbar_exit(EXIT_SUCCESS, US"deliver_msg");
059ec3d9
PH
696 }
697
698 if (dpid > 0)
699 {
57cc2785 700 release_cutthrough_connection(US"passed for delivery");
059ec3d9
PH
701 DEBUG(D_any) debug_printf("forked delivery process %d\n", (int)dpid);
702 }
703 else
57cc2785
JH
704 {
705 cancel_cutthrough_connection(TRUE, US"delivery fork failed");
059ec3d9
PH
706 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: delivery process fork "
707 "failed: %s", strerror(errno));
57cc2785 708 }
059ec3d9
PH
709 }
710 }
711 }
712
713
714/* Carrying on in the parent daemon process... Can't do much if the fork
715failed. Otherwise, keep count of the number of accepting processes and
716remember the pid for ticking off when the child completes. */
717
718if (pid < 0)
059ec3d9 719 never_error(US"daemon: accept process fork failed", US"Fork failed", errno);
059ec3d9
PH
720else
721 {
d7978c0f 722 for (int i = 0; i < smtp_accept_max; ++i)
059ec3d9
PH
723 if (smtp_slots[i].pid <= 0)
724 {
725 smtp_slots[i].pid = pid;
f3ebb786
JH
726 /* Connection closes come asyncronously, so we cannot stack this store */
727 if (smtp_accept_max_per_host)
059ec3d9
PH
728 smtp_slots[i].host_address = string_copy_malloc(sender_host_address);
729 smtp_accept_count++;
730 break;
731 }
059ec3d9 732 DEBUG(D_any) debug_printf("%d SMTP accept process%s running\n",
f3ebb786 733 smtp_accept_count, smtp_accept_count == 1 ? "" : "es");
059ec3d9
PH
734 }
735
736/* Get here via goto in error cases */
737
738ERROR_RETURN:
739
740/* Close the streams associated with the socket which will also close the
741socket fds in this process. We can't do anything if fclose() fails, but
742logging brings it to someone's attention. However, "connection reset by peer"
1f872c80
PH
743isn't really a problem, so skip that one. On Solaris, a dropped connection can
744manifest itself as a broken pipe, so drop that one too. If the streams don't
745exist, something went wrong while setting things up. Make sure the socket
746descriptors are closed, in order to drop the connection. */
059ec3d9 747
f5d25c2b 748if (smtp_out)
059ec3d9 749 {
1f872c80 750 if (fclose(smtp_out) != 0 && errno != ECONNRESET && errno != EPIPE)
059ec3d9
PH
751 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_out) failed: %s",
752 strerror(errno));
753 smtp_out = NULL;
754 }
f1e894f3 755else (void)close(accept_socket);
059ec3d9 756
f5d25c2b 757if (smtp_in)
059ec3d9 758 {
1f872c80 759 if (fclose(smtp_in) != 0 && errno != ECONNRESET && errno != EPIPE)
059ec3d9
PH
760 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_in) failed: %s",
761 strerror(errno));
762 smtp_in = NULL;
763 }
f1e894f3 764else (void)close(dup_accept_socket);
059ec3d9
PH
765
766/* Release any store used in this process, including the store used for holding
767the incoming host address and an expanded active_hostname. */
768
c8899c20 769log_close_all();
90341c71
JH
770interface_address =
771sender_host_address = NULL;
059ec3d9
PH
772store_reset(reset_point);
773sender_host_address = NULL;
774}
775
776
777
778
779/*************************************************
780* Check wildcard listen special cases *
781*************************************************/
782
783/* This function is used when binding and listening on lists of addresses and
784ports. It tests for special cases of wildcard listening, when IPv4 and IPv6
785sockets may interact in different ways in different operating systems. It is
786passed an error number, the list of listening addresses, and the current
787address. Two checks are available: for a previous wildcard IPv6 address, or for
788a following wildcard IPv4 address, in both cases on the same port.
789
790In practice, pairs of wildcard addresses should be adjacent in the address list
791because they are sorted that way below.
792
793Arguments:
794 eno the error number
795 addresses the list of addresses
796 ipa the current IP address
797 back if TRUE, check for previous wildcard IPv6 address
798 if FALSE, check for a following wildcard IPv4 address
799
800Returns: TRUE or FALSE
801*/
802
803static BOOL
804check_special_case(int eno, ip_address_item *addresses, ip_address_item *ipa,
805 BOOL back)
806{
807ip_address_item *ipa2;
808
809/* For the "back" case, if the failure was "address in use" for a wildcard IPv4
810address, seek a previous IPv6 wildcard address on the same port. As it is
811previous, it must have been successfully bound and be listening. Flag it as a
812"6 including 4" listener. */
813
814if (back)
815 {
816 if (eno != EADDRINUSE || ipa->address[0] != 0) return FALSE;
817 for (ipa2 = addresses; ipa2 != ipa; ipa2 = ipa2->next)
818 {
819 if (ipa2->address[1] == 0 && ipa2->port == ipa->port)
820 {
821 ipa2->v6_include_v4 = TRUE;
822 return TRUE;
823 }
824 }
825 }
826
827/* For the "forward" case, if the current address is a wildcard IPv6 address,
828we seek a following wildcard IPv4 address on the same port. */
829
830else
831 {
832 if (ipa->address[0] != ':' || ipa->address[1] != 0) return FALSE;
833 for (ipa2 = ipa->next; ipa2 != NULL; ipa2 = ipa2->next)
834 if (ipa2->address[0] == 0 && ipa->port == ipa2->port) return TRUE;
835 }
836
837return FALSE;
838}
839
840
841
842
bb6e88ff
PH
843/*************************************************
844* Handle terminating subprocesses *
845*************************************************/
846
847/* Handle the termination of child processes. Theoretically, this need be done
848only when sigchld_seen is TRUE, but rumour has it that some systems lose
849SIGCHLD signals at busy times, so to be on the safe side, this function is
850called each time round. It shouldn't be too expensive.
851
852Arguments: none
853Returns: nothing
854*/
855
856static void
857handle_ending_processes(void)
858{
859int status;
860pid_t pid;
861
862while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
863 {
7be682ca
PP
864 DEBUG(D_any)
865 {
866 debug_printf("child %d ended: status=0x%x\n", (int)pid, status);
867#ifdef WCOREDUMP
868 if (WIFEXITED(status))
869 debug_printf(" normal exit, %d\n", WEXITSTATUS(status));
870 else if (WIFSIGNALED(status))
871 debug_printf(" signal exit, signal %d%s\n", WTERMSIG(status),
872 WCOREDUMP(status) ? " (core dumped)" : "");
873#endif
874 }
bb6e88ff 875
8e669ac1 876 /* If it's a listening daemon for which we are keeping track of individual
bb6e88ff
PH
877 subprocesses, deal with an accepting process that has terminated. */
878
8cfd0f7b 879 if (smtp_slots)
bb6e88ff 880 {
f3ebb786 881 int i;
bb6e88ff 882 for (i = 0; i < smtp_accept_max; i++)
bb6e88ff
PH
883 if (smtp_slots[i].pid == pid)
884 {
8cfd0f7b 885 if (smtp_slots[i].host_address)
bb6e88ff
PH
886 store_free(smtp_slots[i].host_address);
887 smtp_slots[i] = empty_smtp_slot;
888 if (--smtp_accept_count < 0) smtp_accept_count = 0;
889 DEBUG(D_any) debug_printf("%d SMTP accept process%s now running\n",
890 smtp_accept_count, (smtp_accept_count == 1)? "" : "es");
891 break;
892 }
bb6e88ff
PH
893 if (i < smtp_accept_max) continue; /* Found an accepting process */
894 }
895
896 /* If it wasn't an accepting process, see if it was a queue-runner
897 process that we are tracking. */
898
0cd5fd23 899 if (queue_pid_slots)
bb6e88ff 900 {
4dc2379a 901 int max = atoi(CS expand_string(queue_run_max));
f3ebb786 902 for (int i = 0; i < max; i++)
bb6e88ff
PH
903 if (queue_pid_slots[i] == pid)
904 {
905 queue_pid_slots[i] = 0;
906 if (--queue_run_count < 0) queue_run_count = 0;
907 DEBUG(D_any) debug_printf("%d queue-runner process%s now running\n",
908 queue_run_count, (queue_run_count == 1)? "" : "es");
909 break;
910 }
bb6e88ff
PH
911 }
912 }
913}
914
059ec3d9
PH
915
916
01446a56
JH
917static void
918set_pid_file_path(void)
919{
920if (override_pid_file_path)
921 pid_file_path = override_pid_file_path;
922
923if (!*pid_file_path)
924 pid_file_path = string_sprintf("%s/exim-daemon.pid", spool_directory);
925}
926
927
928/* Remove the daemon's pidfile. Note: runs with root privilege,
929as a direct child of the daemon. Does not return. */
930
931void
932delete_pid_file(void)
933{
934uschar * daemon_pid = string_sprintf("%d\n", (int)getppid());
935FILE * f;
936
937set_pid_file_path();
938if ((f = Ufopen(pid_file_path, "rb")))
939 {
940 if ( fgets(CS big_buffer, big_buffer_size, f)
941 && Ustrcmp(daemon_pid, big_buffer) == 0
942 )
943 if (Uunlink(pid_file_path) == 0)
944 {
945 DEBUG(D_any)
946 debug_printf("%s unlink: %s\n", pid_file_path, strerror(errno));
947 }
948 else
949 DEBUG(D_any)
950 debug_printf("unlinked %s\n", pid_file_path);
951 fclose(f);
952 }
953else
954 DEBUG(D_any)
955 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
956 pid_file_path));
957exim_exit(EXIT_SUCCESS, US"pid file remover");
958}
959
960
961/* Called by the daemon; exec a child to get the pid file deleted
962since we may require privs for the containing directory */
963
964static void
965daemon_die(void)
966{
967int pid;
968
2f2dd3a5
JH
969if (daemon_notifier_fd >= 0)
970 {
971 close(daemon_notifier_fd);
972 daemon_notifier_fd = -1;
973#ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
974 {
691ca88c 975 uschar * s = expand_string(notifier_socket);
2f2dd3a5
JH
976 DEBUG(D_any) debug_printf("unlinking notifier socket %s\n", s);
977 Uunlink(s);
978 }
979#endif
980 }
981
01446a56
JH
982if (f.running_in_test_harness || write_pid)
983 {
4b01271f 984 if ((pid = exim_fork(US"daemon-del-pidfile")) == 0)
01446a56
JH
985 {
986 if (override_pid_file_path)
987 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 3,
988 "-oP", override_pid_file_path, "-oPX");
989 else
990 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 1, "-oPX");
991
992 /* Control never returns here. */
993 }
994 if (pid > 0)
995 child_close(pid, 1);
996 }
997exim_exit(EXIT_SUCCESS, US"daemon");
998}
999
1000
ff966302
JH
1001/*************************************************
1002* Listener socket for local work prompts *
1003*************************************************/
1004
1005static void
1006daemon_notifier_socket(void)
1007{
1008int fd;
1009const uschar * where;
3978c243 1010struct sockaddr_un sa_un = {.sun_family = AF_UNIX};
04403ab0 1011int len;
ff966302 1012
691ca88c
JH
1013if (override_local_interfaces && !override_pid_file_path)
1014 {
1015 DEBUG(D_any)
1016 debug_printf("-oX used without -oP so not creating notifier socket\n");
1017 return;
1018 }
1019
1020DEBUG(D_any) debug_printf("creating notifier socket\n");
ff966302 1021
ff966302 1022#ifdef SOCK_CLOEXEC
2f2dd3a5 1023if ((fd = socket(PF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0)
4a9f055c 1024 { where = US"socket"; goto bad; }
ff966302 1025#else
4a9f055c
JH
1026if ((fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0)
1027 { where = US"socket"; goto bad; }
ff966302
JH
1028(void)fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
1029#endif
1030
2f2dd3a5 1031#ifdef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
3978c243 1032sa_un.sun_path[0] = 0; /* Abstract local socket addr - Linux-specific? */
04403ab0 1033len = offsetof(struct sockaddr_un, sun_path) + 1
691ca88c
JH
1034 + snprintf(sa_un.sun_path+1, sizeof(sa_un.sun_path)-1, "%s",
1035 expand_string(notifier_socket));
1036DEBUG(D_any) debug_printf(" @%s\n", sa_un.sun_path+1);
2f2dd3a5
JH
1037#else /* filesystem-visible and persistent; will neeed removal */
1038len = offsetof(struct sockaddr_un, sun_path)
691ca88c
JH
1039 + snprintf(sa_un.sun_path, sizeof(sa_un.sun_path), "%s",
1040 expand_string(notifier_socket));
1041DEBUG(D_any) debug_printf(" %s\n", sa_un.sun_path);
2f2dd3a5 1042#endif
04403ab0 1043
3978c243 1044if (bind(fd, (const struct sockaddr *)&sa_un, len) < 0)
4a9f055c 1045 { where = US"bind"; goto bad; }
ff966302 1046
5399df80 1047#ifdef SO_PASSCRED /* Linux */
2f2dd3a5 1048if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0)
4a9f055c 1049 { where = US"SO_PASSCRED"; goto bad2; }
2f2dd3a5 1050#elif defined(LOCAL_CREDS) /* FreeBSD-ish */
4a9f055c
JH
1051if (setsockopt(fd, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
1052 { where = US"LOCAL_CREDS"; goto bad2; }
2f2dd3a5 1053#endif
ff966302
JH
1054
1055/* debug_printf("%s: fd %d\n", __FUNCTION__, fd); */
1056daemon_notifier_fd = fd;
1057return;
1058
4a9f055c
JH
1059bad2:
1060#ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1061 Uunlink(sa_un.sun_path);
1062#endif
ff966302 1063bad:
4a9f055c 1064 log_write(0, LOG_MAIN|LOG_PANIC, "%s %s: %s",
ff966302 1065 __FUNCTION__, where, strerror(errno));
4a9f055c
JH
1066 close(fd);
1067 return;
ff966302
JH
1068}
1069
1070
1071static uschar queuerun_msgid[MESSAGE_ID_LENGTH+1];
1072
1073/* Return TRUE if a sigalrm should be emulated */
1074static BOOL
1075daemon_notification(void)
1076{
1077uschar buf[256], cbuf[256];
3978c243 1078struct sockaddr_un sa_un;
017de05c 1079struct iovec iov = {.iov_base = buf, .iov_len = sizeof(buf)-1};
3978c243
JH
1080struct msghdr msg = { .msg_name = &sa_un,
1081 .msg_namelen = sizeof(sa_un),
ff966302
JH
1082 .msg_iov = &iov,
1083 .msg_iovlen = 1,
1084 .msg_control = cbuf,
1085 .msg_controllen = sizeof(cbuf)
1086 };
1087ssize_t sz;
1088struct cmsghdr * cp;
1089
1090buf[sizeof(buf)-1] = 0;
1091if ((sz = recvmsg(daemon_notifier_fd, &msg, 0)) <= 0) return FALSE;
1092if (sz >= sizeof(buf)) return FALSE;
1093
04403ab0
JH
1094#ifdef notdef
1095debug_printf("addrlen %d\n", msg.msg_namelen);
1096#endif
2f2dd3a5 1097DEBUG(D_queue_run) debug_printf("%s from addr '%s%.*s'\n", __FUNCTION__,
3978c243
JH
1098 *sa_un.sun_path ? "" : "@",
1099 (int)msg.msg_namelen - (*sa_un.sun_path ? 0 : 1),
1100 sa_un.sun_path + (*sa_un.sun_path ? 0 : 1));
04403ab0
JH
1101
1102/* Refuse to handle the item unless the peer has good credentials */
f254e592
JH
1103#ifdef SCM_CREDENTIALS
1104# define EXIM_SCM_CR_TYPE SCM_CREDENTIALS
5399df80 1105#elif defined(LOCAL_CREDS) && defined(SCM_CREDS)
f254e592
JH
1106# define EXIM_SCM_CR_TYPE SCM_CREDS
1107#else
2f2dd3a5
JH
1108 /* The OS has no way to get the creds of the caller (for a unix/datagram socket.
1109 Punt; don't try to check. */
f254e592 1110#endif
04403ab0 1111
2f2dd3a5 1112#ifdef EXIM_SCM_CR_TYPE
ff966302
JH
1113for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg);
1114 cp;
1115 cp = CMSG_NXTHDR(&msg, cp))
f254e592 1116 if (cp->cmsg_level == SOL_SOCKET && cp->cmsg_type == EXIM_SCM_CR_TYPE)
ff966302 1117 {
2f2dd3a5 1118# ifdef SCM_CREDENTIALS /* Linux */
ff966302
JH
1119 struct ucred * cr = (struct ucred *) CMSG_DATA(cp);
1120 if (cr->uid && cr->uid != exim_uid)
1121 {
1122 DEBUG(D_queue_run) debug_printf("%s: sender creds pid %d uid %d gid %d\n",
1123 __FUNCTION__, (int)cr->pid, (int)cr->uid, (int)cr->gid);
1124 return FALSE;
2f2dd3a5
JH
1125 }
1126# elif defined(LOCAL_CREDS) /* BSD-ish */
5399df80
JH
1127 struct sockcred * cr = (struct sockcred *) CMSG_DATA(cp);
1128 if (cr->sc_uid && cr->sc_uid != exim_uid)
f254e592 1129 {
5399df80
JH
1130 DEBUG(D_queue_run) debug_printf("%s: sender creds pid ??? uid %d gid %d\n",
1131 __FUNCTION__, (int)cr->sc_uid, (int)cr->sc_gid);
f254e592 1132 return FALSE;
ff966302 1133 }
2f2dd3a5 1134# endif
ff966302
JH
1135 break;
1136 }
2f2dd3a5 1137#endif
ff966302
JH
1138
1139buf[sz] = 0;
1140switch (buf[0])
1141 {
4c2efd7a 1142#ifdef EXPERIMENTAL_QUEUE_RAMP
ff966302
JH
1143 case NOTIFY_MSG_QRUN:
1144 /* this should be a message_id */
1145 DEBUG(D_queue_run)
1146 debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1);
1147 memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1);
1148 return TRUE;
4c2efd7a 1149#endif /*EXPERIMENTAL_QUEUE_RAMP*/
04403ab0
JH
1150
1151 case NOTIFY_QUEUE_SIZE_REQ:
1152 {
1153 uschar buf[16];
1154 int len = snprintf(CS buf, sizeof(buf), "%u", queue_count_cached());
1155
1156 DEBUG(D_queue_run)
1157 debug_printf("%s: queue size request: %s\n", __FUNCTION__, buf);
1158
f254e592 1159 if (sendto(daemon_notifier_fd, buf, len, 0,
3978c243 1160 (const struct sockaddr *)&sa_un, msg.msg_namelen) < 0)
04403ab0
JH
1161 log_write(0, LOG_MAIN|LOG_PANIC,
1162 "%s: sendto: %s\n", __FUNCTION__, strerror(errno));
1163 return FALSE;
1164 }
ff966302
JH
1165 }
1166return FALSE;
1167}
ff966302
JH
1168
1169
059ec3d9
PH
1170/*************************************************
1171* Exim Daemon Mainline *
1172*************************************************/
1173
1174/* The daemon can do two jobs, either of which is optional:
1175
1176(1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1177each one. This is requested by the -bd option, with -oX specifying the SMTP
1178port on which to listen (for testing).
1179
1180(2) Spawns a queue-running process every so often. This is controlled by the
1181-q option with a an interval time. (If no time is given, a single queue run
1182is done from the main function, and control doesn't get here.)
1183
1184Root privilege is required in order to attach to port 25. Some systems require
1185it when calling socket() rather than bind(). To cope with all cases, we run as
1186root for both socket() and bind(). Some systems also require root in order to
1187write to the pid file directory. This function must therefore be called as root
1188if it is to work properly in all circumstances. Once the socket is bound and
1189the pid file written, root privilege is given up if there is an exim uid.
1190
1191There are no arguments to this function, and it never returns. */
1192
1193void
1194daemon_go(void)
1195{
ebeaf996 1196struct passwd *pw;
059ec3d9
PH
1197int *listen_sockets = NULL;
1198int listen_socket_count = 0;
1199ip_address_item *addresses = NULL;
9ee44efb 1200time_t last_connection_time = (time_t)0;
4dc2379a 1201int local_queue_run_max = atoi(CS expand_string(queue_run_max));
059ec3d9
PH
1202
1203/* If any debugging options are set, turn on the D_pid bit so that all
1204debugging lines get the pid added. */
1205
1206DEBUG(D_any|D_v) debug_selector |= D_pid;
1207
8768d548 1208if (f.inetd_wait_mode)
9ee44efb 1209 {
9ee44efb 1210 listen_socket_count = 1;
f3ebb786 1211 listen_sockets = store_get(sizeof(int), FALSE);
9ee44efb
PP
1212 (void) close(3);
1213 if (dup2(0, 3) == -1)
9ee44efb
PP
1214 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1215 "failed to dup inetd socket safely away: %s", strerror(errno));
d4ff61d1 1216
9ee44efb
PP
1217 listen_sockets[0] = 3;
1218 (void) close(0);
1219 (void) close(1);
1220 (void) close(2);
1221 exim_nullstd();
1222
1223 if (debug_file == stderr)
1224 {
1225 /* need a call to log_write before call to open debug_file, so that
1226 log.c:file_path has been initialised. This is unfortunate. */
1227 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1228
1229 fclose(debug_file);
1230 debug_file = NULL;
1231 exim_nullstd(); /* re-open fd2 after we just closed it again */
1232 debug_logging_activate(US"-wait", NULL);
1233 }
1234
1235 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1236
1237 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1238 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1239
d4ff61d1
JH
1240 if (tcp_nodelay)
1241 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1242 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1243 strerror(errno));
9ee44efb
PP
1244 }
1245
1246
8768d548 1247if (f.inetd_wait_mode || f.daemon_listen)
9ee44efb
PP
1248 {
1249 /* If any option requiring a load average to be available during the
1250 reception of a message is set, call os_getloadavg() while we are root
1251 for those OS for which this is necessary the first time it is called (in
1252 order to perform an "open" on the kernel memory file). */
1253
1254 #ifdef LOAD_AVG_NEEDS_ROOT
1255 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1256 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1257 (void)os_getloadavg();
1258 #endif
1259 }
1260
059ec3d9
PH
1261
1262/* Do the preparation for setting up a listener on one or more interfaces, and
1263possible on various ports. This is controlled by the combination of
1264local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1265(which is a list of default ports to use for those items in local_interfaces
1266that do not specify a port). The -oX command line option can be used to
1267override one or both of these options.
1268
1269If local_interfaces is not set, the default is to listen on all interfaces.
1270When it is set, it can include "all IPvx interfaces" as an item. This is useful
1271when different ports are in use.
1272
1273It turns out that listening on all interfaces is messy in an IPv6 world,
1274because several different implementation approaches have been taken. This code
1275is now supposed to work with all of them. The point of difference is whether an
1276IPv6 socket that is listening on all interfaces will receive incoming IPv4
1277calls or not. We also have to cope with the case when IPv6 libraries exist, but
1278there is no IPv6 support in the kernel.
1279
1280. On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1281 addresses. However, if an IPv4 socket is also listening on all interfaces,
1282 calls are directed to the appropriate socket.
1283
1284. On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1285 give them as mapped addresses, but an attempt also to listen on an IPv4
1286 socket on all interfaces causes an error.
1287
1288. On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1289 two sockets if you want to accept both kinds of call.
1290
1291. FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1292 can be turned off, to make it behave like the versions of Linux described
1293 above.
1294
1295. I heard a report that the USAGI IPv6 stack for Linux has implemented
1296 IPV6_V6ONLY.
1297
1298So, what we do when IPv6 is supported is as follows:
1299
1300 (1) After it is set up, the list of interfaces is scanned for wildcard
1301 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1302 port, the list is re-arranged so that they are together, with the IPv6
1303 wildcard first.
1304
1305 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1306 carry on if an IPv4 wildcard socket for the same port follows later in the
1307 list. This allows Exim to carry on in the case when the kernel has no IPv6
1308 support.
1309
1310 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1311 option is defined. However, if setting fails, carry on regardless (but log
1312 the incident).
1313
1314 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1315 error.
1316
1317 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1318 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1319 port (which must have succeeded or we wouldn't have got this far), we
1320 assume we are in the situation where just a single socket is permitted,
1321 and ignore the error.
1322
1323Phew!
1324
1325The preparation code decodes options and sets up the relevant data. We do this
1326first, so that we can return non-zero if there are any syntax errors, and also
1327write to stderr. */
1328
8768d548 1329if (f.daemon_listen && !f.inetd_wait_mode)
059ec3d9
PH
1330 {
1331 int *default_smtp_port;
1332 int sep;
1333 int pct = 0;
1334 uschar *s;
55414b25 1335 const uschar * list;
059ec3d9
PH
1336 uschar *local_iface_source = US"local_interfaces";
1337 ip_address_item *ipa;
1338 ip_address_item **pipa;
1339
059ec3d9
PH
1340 /* If -oX was used, disable the writing of a pid file unless -oP was
1341 explicitly used to force it. Then scan the string given to -oX. Any items
1342 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1343 Any other items are used to override local_interfaces. */
1344
acec9514 1345 if (override_local_interfaces)
059ec3d9 1346 {
acec9514
JH
1347 gstring * new_smtp_port = NULL;
1348 gstring * new_local_interfaces = NULL;
059ec3d9 1349
01446a56 1350 if (!override_pid_file_path) write_pid = FALSE;
059ec3d9
PH
1351
1352 list = override_local_interfaces;
1353 sep = 0;
55414b25 1354 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
059ec3d9
PH
1355 {
1356 uschar joinstr[4];
01446a56 1357 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
059ec3d9 1358
acec9514 1359 if (!*gp)
059ec3d9
PH
1360 {
1361 joinstr[0] = sep;
1362 joinstr[1] = ' ';
acec9514 1363 *gp = string_catn(*gp, US"<", 1);
059ec3d9
PH
1364 }
1365
acec9514
JH
1366 *gp = string_catn(*gp, joinstr, 2);
1367 *gp = string_cat (*gp, s);
059ec3d9
PH
1368 }
1369
acec9514 1370 if (new_smtp_port)
059ec3d9 1371 {
acec9514 1372 daemon_smtp_port = string_from_gstring(new_smtp_port);
059ec3d9
PH
1373 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1374 daemon_smtp_port);
1375 }
1376
acec9514 1377 if (new_local_interfaces)
059ec3d9 1378 {
acec9514 1379 local_interfaces = string_from_gstring(new_local_interfaces);
059ec3d9
PH
1380 local_iface_source = US"-oX data";
1381 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1382 local_interfaces);
1383 }
1384 }
1385
1386 /* Create a list of default SMTP ports, to be used if local_interfaces
4c04137d 1387 contains entries without explicit ports. First count the number of ports, then
059ec3d9
PH
1388 build a translated list in a vector. */
1389
1390 list = daemon_smtp_port;
1391 sep = 0;
55414b25 1392 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
059ec3d9 1393 pct++;
f3ebb786 1394 default_smtp_port = store_get((pct+1) * sizeof(int), FALSE);
059ec3d9
PH
1395 list = daemon_smtp_port;
1396 sep = 0;
1397 for (pct = 0;
55414b25 1398 (s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size));
059ec3d9
PH
1399 pct++)
1400 {
1401 if (isdigit(*s))
1402 {
1403 uschar *end;
1404 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1405 if (end != s + Ustrlen(s))
1406 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1407 }
1408 else
1409 {
1410 struct servent *smtp_service = getservbyname(CS s, "tcp");
071c51f7 1411 if (!smtp_service)
059ec3d9
PH
1412 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1413 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1414 }
1415 }
1416 default_smtp_port[pct] = 0;
1417
071c51f7
JH
1418 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1419
1420 list = tls_in.on_connect_ports;
1421 sep = 0;
1422 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1423 if (!isdigit(*s))
1424 {
acec9514 1425 gstring * g = NULL;
4226691b 1426
071c51f7
JH
1427 list = tls_in.on_connect_ports;
1428 tls_in.on_connect_ports = NULL;
1429 sep = 0;
1430 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1431 {
1432 if (!isdigit(*s))
1433 {
4226691b 1434 struct servent * smtp_service = getservbyname(CS s, "tcp");
071c51f7
JH
1435 if (!smtp_service)
1436 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
4226691b 1437 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
071c51f7 1438 }
acec9514 1439 g = string_append_listele(g, ':', s);
071c51f7 1440 }
acec9514
JH
1441 if (g)
1442 tls_in.on_connect_ports = g->s;
071c51f7
JH
1443 break;
1444 }
1445
059ec3d9
PH
1446 /* Create the list of local interfaces, possibly with ports included. This
1447 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1448 values are converted below. */
1449
1450 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1451
1452 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1453 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1454 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1455 anyway, but we need to know which are the wildcard addresses, and the shorter
1456 strings are neater.
1457
1458 In the same scan, fill in missing port numbers from the default list. When
1459 there is more than one item in the list, extra items are created. */
1460
b891534f 1461 for (ipa = addresses; ipa; ipa = ipa->next)
059ec3d9 1462 {
b891534f
JH
1463 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1464 ipa->address[0] = 0;
059ec3d9
PH
1465 else if (Ustrcmp(ipa->address, "::0") == 0)
1466 {
1467 ipa->address[0] = ':';
1468 ipa->address[1] = 0;
1469 }
1470
1471 if (ipa->port > 0) continue;
1472
1473 if (daemon_smtp_port[0] <= 0)
1474 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1475 "%s and daemon_smtp_port is unset; cannot start daemon",
b891534f
JH
1476 ipa->address[0] == 0 ? US"\"all IPv4\"" :
1477 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
1478
059ec3d9 1479 ipa->port = default_smtp_port[0];
d7978c0f 1480 for (int i = 1; default_smtp_port[i] > 0; i++)
059ec3d9 1481 {
f3ebb786 1482 ip_address_item *new = store_get(sizeof(ip_address_item), FALSE);
b891534f 1483
059ec3d9
PH
1484 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1485 new->port = default_smtp_port[i];
1486 new->next = ipa->next;
1487 ipa->next = new;
1488 ipa = new;
1489 }
1490 }
1491
1492 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1493 wildcard for the same port, ensure that (a) they are together and (b) the
1494 IPv6 address comes first. This makes handling the messy features easier, and
1495 also simplifies the construction of the "daemon started" log line. */
1496
1497 pipa = &addresses;
b891534f 1498 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
059ec3d9
PH
1499 {
1500 ip_address_item *ipa2;
1501
1502 /* Handle an IPv4 wildcard */
1503
1504 if (ipa->address[0] == 0)
b891534f 1505 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
059ec3d9
PH
1506 {
1507 ip_address_item *ipa3 = ipa2->next;
1508 if (ipa3->address[0] == ':' &&
1509 ipa3->address[1] == 0 &&
1510 ipa3->port == ipa->port)
1511 {
1512 ipa2->next = ipa3->next;
1513 ipa3->next = ipa;
1514 *pipa = ipa3;
1515 break;
1516 }
1517 }
059ec3d9
PH
1518
1519 /* Handle an IPv6 wildcard. */
1520
1521 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
b891534f 1522 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
059ec3d9
PH
1523 {
1524 ip_address_item *ipa3 = ipa2->next;
1525 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1526 {
1527 ipa2->next = ipa3->next;
1528 ipa3->next = ipa->next;
1529 ipa->next = ipa3;
1530 ipa = ipa3;
1531 break;
1532 }
1533 }
059ec3d9
PH
1534 }
1535
1536 /* Get a vector to remember all the sockets in */
1537
b891534f 1538 for (ipa = addresses; ipa; ipa = ipa->next)
059ec3d9 1539 listen_socket_count++;
f3ebb786 1540 listen_sockets = store_get(sizeof(int) * listen_socket_count, FALSE);
059ec3d9 1541
9ee44efb
PP
1542 } /* daemon_listen but not inetd_wait_mode */
1543
8768d548 1544if (f.daemon_listen)
9ee44efb
PP
1545 {
1546
059ec3d9
PH
1547 /* Do a sanity check on the max connects value just to save us from getting
1548 a huge amount of store. */
1549
1550 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1551
1552 /* There's no point setting smtp_accept_queue unless it is less than the max
1553 connects limit. The configuration reader ensures that the max is set if the
1554 queue-only option is set. */
1555
1556 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1557
1558 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1559 track of them for total number and queue/host limits. */
1560
1561 if (smtp_accept_max > 0)
1562 {
f3ebb786 1563 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), FALSE);
d7978c0f 1564 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
059ec3d9
PH
1565 }
1566 }
1567
76a2d7ba
PH
1568/* The variable background_daemon is always false when debugging, but
1569can also be forced false in order to keep a non-debugging daemon in the
1570foreground. If background_daemon is true, close all open file descriptors that
9ee44efb
PP
1571we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1572do this for inetd_wait mode.
76a2d7ba
PH
1573
1574This is protection against any called functions (in libraries, or in
1575Perl, or whatever) that think they can write to stderr (or stdout). Before this
1576was added, it was quite likely that an SMTP connection would use one of these
1577file descriptors, in which case writing random stuff to it caused chaos.
1578
1579Then disconnect from the controlling terminal, Most modern Unixes seem to have
1580setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1581setsid() can be #defined as a no-op, or as something else. */
059ec3d9 1582
8768d548 1583if (f.background_daemon || f.inetd_wait_mode)
059ec3d9 1584 {
76a2d7ba
PH
1585 log_close_all(); /* Just in case anything was logged earlier */
1586 search_tidyup(); /* Just in case any were used in reading the config. */
f1e894f3
PH
1587 (void)close(0); /* Get rid of stdin/stdout/stderr */
1588 (void)close(1);
1589 (void)close(2);
8e669ac1 1590 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
059ec3d9 1591 log_stderr = NULL; /* So no attempt to copy paniclog output */
9ee44efb 1592 }
059ec3d9 1593
8768d548 1594if (f.background_daemon)
9ee44efb 1595 {
059ec3d9 1596 /* If the parent process of this one has pid == 1, we are re-initializing the
8e669ac1 1597 daemon as the result of a SIGHUP. In this case, there is no need to do
76a2d7ba
PH
1598 anything, because the controlling terminal has long gone. Otherwise, fork, in
1599 case current process is a process group leader (see 'man setsid' for an
1600 explanation) before calling setsid(). */
059ec3d9
PH
1601
1602 if (getppid() != 1)
1603 {
8e9fdd63 1604 pid_t pid = exim_fork(US"daemon");
059ec3d9
PH
1605 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1606 "fork() failed when starting daemon: %s", strerror(errno));
1607 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1608 (void)setsid(); /* release controlling terminal */
1609 }
1610 }
1611
1612/* We are now in the disconnected, daemon process (unless debugging). Set up
1613the listening sockets if required. */
1614
4c2efd7a 1615daemon_notifier_socket();
ff966302 1616
8768d548 1617if (f.daemon_listen && !f.inetd_wait_mode)
059ec3d9
PH
1618 {
1619 int sk;
059ec3d9
PH
1620 ip_address_item *ipa;
1621
1622 /* For each IP address, create a socket, bind it to the appropriate port, and
1623 start listening. See comments above about IPv6 sockets that may or may not
1624 accept IPv4 calls when listening on all interfaces. We also have to cope with
1625 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1626 listening, provided a wildcard IPv4 socket for the same port follows. */
1627
1628 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1629 {
1630 BOOL wildcard;
1631 ip_address_item *ipa2;
059ec3d9
PH
1632 int af;
1633
1634 if (Ustrchr(ipa->address, ':') != NULL)
1635 {
1636 af = AF_INET6;
1637 wildcard = ipa->address[1] == 0;
1638 }
1639 else
1640 {
1641 af = AF_INET;
1642 wildcard = ipa->address[0] == 0;
1643 }
1644
96f5fe4c 1645 if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0)
059ec3d9
PH
1646 {
1647 if (check_special_case(0, addresses, ipa, FALSE))
1648 {
1649 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1650 "listening (%s): will use IPv4", strerror(errno));
1651 goto SKIP_SOCKET;
1652 }
1653 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1654 (af == AF_INET6)? '6' : '4', strerror(errno));
1655 }
1656
1657 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1658 available. Just log failure (can get protocol not available, just like
1659 socket creation can). */
1660
b891534f 1661#ifdef IPV6_V6ONLY
059ec3d9 1662 if (af == AF_INET6 && wildcard &&
5903c6ff 1663 setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, CS (&on),
059ec3d9
PH
1664 sizeof(on)) < 0)
1665 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1666 "socket failed (%s): carrying on without it", strerror(errno));
b891534f 1667#endif /* IPV6_V6ONLY */
059ec3d9
PH
1668
1669 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1670 is being handled. Without this, a connection will prevent reuse of the
1671 smtp port for listening. */
1672
1673 if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR,
5903c6ff 1674 US (&on), sizeof(on)) < 0)
059ec3d9
PH
1675 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1676 "failed when starting daemon: %s", strerror(errno));
1677
1678 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1679 disable this because it breaks some broken clients. */
1680
1681 if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY,
5903c6ff 1682 US (&on), sizeof(on));
059ec3d9
PH
1683
1684 /* Now bind the socket to the required port; if Exim is being restarted
1685 it may not always be possible to bind immediately, even with SO_REUSEADDR
1686 set, so try 10 times, waiting between each try. After 10 failures, we give
1687 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1688 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1689 address for the same port, ignore the error on the grounds that we must be
1690 in a system where the IPv6 socket accepts both kinds of call. This is
1691 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1692 listen() stage instead. */
1693
6af7e591 1694#ifdef TCP_FASTOPEN
8768d548 1695 f.tcp_fastopen_ok = TRUE;
6af7e591 1696#endif
059ec3d9
PH
1697 for(;;)
1698 {
1699 uschar *msg, *addr;
1700 if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break;
1701 if (check_special_case(errno, addresses, ipa, TRUE))
1702 {
1703 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1704 "listen() success; EADDRINUSE ignored\n");
f1e894f3 1705 (void)close(listen_sockets[sk]);
059ec3d9
PH
1706 goto SKIP_SOCKET;
1707 }
1708 msg = US strerror(errno);
b891534f
JH
1709 addr = wildcard
1710 ? af == AF_INET6
1711 ? US"(any IPv6)"
1712 : US"(any IPv4)"
1713 : ipa->address;
4aee0225 1714 if (daemon_startup_retries <= 0)
059ec3d9
PH
1715 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1716 "socket bind() to port %d for address %s failed: %s: "
1717 "daemon abandoned", ipa->port, addr, msg);
1718 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
4aee0225
PH
1719 "failed: %s: waiting %s before trying again (%d more %s)",
1720 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1721 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1722 daemon_startup_retries--;
1723 sleep(daemon_startup_sleep);
059ec3d9
PH
1724 }
1725
1726 DEBUG(D_any)
059ec3d9
PH
1727 if (wildcard)
1728 debug_printf("listening on all interfaces (IPv%c) port %d\n",
fb05276a 1729 af == AF_INET6 ? '6' : '4', ipa->port);
059ec3d9
PH
1730 else
1731 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
fb05276a 1732
b536a578 1733#if defined(TCP_FASTOPEN) && !defined(__APPLE__)
590faf89
JH
1734 if ( f.tcp_fastopen_ok
1735 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
4670e9d3 1736 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
6af7e591 1737 {
a23ff3b4 1738 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
8768d548 1739 f.tcp_fastopen_ok = FALSE;
6af7e591 1740 }
fb05276a 1741#endif
059ec3d9
PH
1742
1743 /* Start listening on the bound socket, establishing the maximum backlog of
1744 connections that is allowed. On success, continue to the next address. */
1745
b536a578
JH
1746 if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0)
1747 {
1748#if defined(TCP_FASTOPEN) && defined(__APPLE__)
1749 if ( f.tcp_fastopen_ok
1750 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1751 &on, sizeof(on)))
1752 {
1753 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1754 f.tcp_fastopen_ok = FALSE;
1755 }
1756#endif
1757 continue;
1758 }
059ec3d9
PH
1759
1760 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1761 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1762 and there was a previous successful IPv6 wildcard listen on the same port,
1763 we want to ignore the error on the grounds that we must be in a system
1764 where the IPv6 socket accepts both kinds of call. */
1765
1766 if (!check_special_case(errno, addresses, ipa, TRUE))
1767 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
fb05276a
JH
1768 wildcard
1769 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
059ec3d9
PH
1770 strerror(errno));
1771
1772 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1773 "listen() success; EADDRINUSE ignored\n");
f1e894f3 1774 (void)close(listen_sockets[sk]);
059ec3d9
PH
1775
1776 /* Come here if there has been a problem with the socket which we
1777 are going to ignore. We remove the address from the chain, and back up the
1778 counts. */
1779
b891534f 1780 SKIP_SOCKET:
059ec3d9
PH
1781 sk--; /* Back up the count */
1782 listen_socket_count--; /* Reduce the total */
1783 if (ipa == addresses) addresses = ipa->next; else
1784 {
1785 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1786 ipa2->next = ipa->next;
1787 ipa = ipa2;
1788 }
1789 } /* End of bind/listen loop for each address */
1790 } /* End of setup for listening */
1791
1792
1793/* If we are not listening, we want to write a pid file only if -oP was
1794explicitly given. */
1795
b891534f
JH
1796else if (!override_pid_file_path)
1797 write_pid = FALSE;
059ec3d9
PH
1798
1799/* Write the pid to a known file for assistance in identification, if required.
1800We do this before giving up root privilege, because on some systems it is
1801necessary to be root in order to write into the pid file directory. There's
1802nothing to stop multiple daemons running, as long as no more than one listens
1803on a given TCP/IP port on the same interface(s). However, in these
1804circumstances it gets far too complicated to mess with pid file names
1805automatically. Consequently, Exim 4 writes a pid file only
1806
1807 (a) When running in the test harness, or
1808 (b) When -bd is used and -oX is not used, or
1809 (c) When -oP is used to supply a path.
1810
1811The variable daemon_write_pid is used to control this. */
1812
8768d548 1813if (f.running_in_test_harness || write_pid)
059ec3d9
PH
1814 {
1815 FILE *f;
1816
01446a56 1817 set_pid_file_path();
b891534f 1818 if ((f = modefopen(pid_file_path, "wb", 0644)))
059ec3d9 1819 {
ff790e47 1820 (void)fprintf(f, "%d\n", (int)getpid());
ff790e47 1821 (void)fclose(f);
059ec3d9
PH
1822 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1823 }
1824 else
059ec3d9
PH
1825 DEBUG(D_any)
1826 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
1827 pid_file_path));
059ec3d9
PH
1828 }
1829
1830/* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1831
1832sighup_seen = FALSE;
1833signal(SIGHUP, sighup_handler);
1834
1835/* Give up root privilege at this point (assuming that exim_uid and exim_gid
1836are not root). The third argument controls the running of initgroups().
1837Normally we do this, in order to set up the groups for the Exim user. However,
1838if we are not root at this time - some odd installations run that way - we
1839cannot do this. */
1840
1841exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1842
ebeaf996
PH
1843/* Update the originator_xxx fields so that received messages as listed as
1844coming from Exim, not whoever started the daemon. */
1845
1846originator_uid = exim_uid;
1847originator_gid = exim_gid;
f3ebb786
JH
1848originator_login = (pw = getpwuid(exim_uid))
1849 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
ebeaf996 1850
059ec3d9
PH
1851/* Get somewhere to keep the list of queue-runner pids if we are keeping track
1852of them (and also if we are doing queue runs). */
1853
0cd5fd23 1854if (queue_interval > 0 && local_queue_run_max > 0)
059ec3d9 1855 {
f3ebb786 1856 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t), FALSE);
d7978c0f 1857 for (int i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
059ec3d9
PH
1858 }
1859
01446a56
JH
1860/* Set up the handler for termination of child processes, and the one
1861telling us to die. */
059ec3d9
PH
1862
1863sigchld_seen = FALSE;
7d468ab8 1864os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
059ec3d9 1865
01446a56
JH
1866sigterm_seen = FALSE;
1867os_non_restarting_signal(SIGTERM, main_sigterm_handler);
1868
059ec3d9
PH
1869/* If we are to run the queue periodically, pretend the alarm has just gone
1870off. This will cause the first queue-runner to get kicked off straight away. */
1871
1872sigalrm_seen = (queue_interval > 0);
1873
1874/* Log the start up of a daemon - at least one of listening or queue running
1875must be set up. */
1876
8768d548 1877if (f.inetd_wait_mode)
9ee44efb
PP
1878 {
1879 uschar *p = big_buffer;
1880
1881 if (inetd_wait_timeout >= 0)
1882 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
1883 else
1884 sprintf(CS p, "with no wait timeout");
1885
1886 log_write(0, LOG_MAIN,
1887 "exim %s daemon started: pid=%d, launched with listening socket, %s",
1888 version_string, getpid(), big_buffer);
2f21487f 1889 set_process_info("daemon(%s): pre-listening socket", version_string);
9ee44efb
PP
1890
1891 /* set up the timeout logic */
ff966302 1892 sigalrm_seen = TRUE;
9ee44efb
PP
1893 }
1894
8768d548 1895else if (f.daemon_listen)
059ec3d9 1896 {
059ec3d9
PH
1897 int smtp_ports = 0;
1898 int smtps_ports = 0;
254f38d1
JH
1899 ip_address_item * ipa;
1900 uschar * p;
e37f8a84
JH
1901 uschar * qinfo = queue_interval > 0
1902 ? string_sprintf("-q%s", readconf_printtime(queue_interval))
1903 : US"no queue runs";
059ec3d9
PH
1904
1905 /* Build a list of listening addresses in big_buffer, but limit it to 10
1906 items. The style is for backwards compatibility.
1907
1908 It is now possible to have some ports listening for SMTPS (the old,
1909 deprecated protocol that starts TLS without using STARTTLS), and others
1910 listening for standard SMTP. Keep their listings separate. */
1911
254f38d1 1912 for (int j = 0, i; j < 2; j++)
059ec3d9 1913 {
e37f8a84 1914 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
b891534f
JH
1915 {
1916 /* First time round, look for SMTP ports; second time round, look for
254f38d1 1917 SMTPS ports. Build IP+port strings. */
b891534f
JH
1918
1919 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1920 {
1921 if (j == 0)
254f38d1 1922 smtp_ports++;
b891534f 1923 else
254f38d1 1924 smtps_ports++;
b891534f
JH
1925
1926 /* Now the information about the port (and sometimes interface) */
1927
1928 if (ipa->address[0] == ':' && ipa->address[1] == 0)
e4d0fc93 1929 { /* v6 wildcard */
b891534f
JH
1930 if (ipa->next && ipa->next->address[0] == 0 &&
1931 ipa->next->port == ipa->port)
1932 {
254f38d1
JH
1933 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
1934 (ipa = ipa->next)->log = NULL;
b891534f
JH
1935 }
1936 else if (ipa->v6_include_v4)
254f38d1 1937 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
b891534f 1938 else
254f38d1 1939 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
b891534f 1940 }
e4d0fc93 1941 else if (ipa->address[0] == 0) /* v4 wildcard */
254f38d1 1942 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
e4d0fc93 1943 else /* check for previously-seen IP */
b891534f 1944 {
254f38d1 1945 ip_address_item * i2;
e4d0fc93
JH
1946 for (i2 = addresses; i2 != ipa; i2 = i2->next)
1947 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
1948 && Ustrcmp(ipa->address, i2->address) == 0
1949 )
1950 { /* found; append port to list */
254f38d1
JH
1951 for (p = i2->log; *p; ) p++; /* end of existing string */
1952 if (*--p == '}') *p = '\0'; /* drop EOL */
1953 while (isdigit(*--p)) ; /* char before port */
1954
1955 i2->log = *p == ':' /* no list yet? */
1956 ? string_sprintf("%.*s{%s,%d}",
1957 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
1958 : string_sprintf("%s,%d}", i2->log, ipa->port);
1959 ipa->log = NULL;
e4d0fc93
JH
1960 break;
1961 }
1962 if (i2 == ipa) /* first-time IP */
254f38d1 1963 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
b891534f 1964 }
b891534f
JH
1965 }
1966 }
254f38d1 1967 }
059ec3d9 1968
254f38d1
JH
1969 p = big_buffer;
1970 for (int j = 0, i; j < 2; j++)
1971 {
1972 /* First time round, look for SMTP ports; second time round, look for
1973 SMTPS ports. For the first one of each, insert leading text. */
1974
1975 if (j == 0)
059ec3d9 1976 {
254f38d1
JH
1977 if (smtp_ports > 0)
1978 p += sprintf(CS p, "SMTP on");
059ec3d9 1979 }
254f38d1
JH
1980 else
1981 if (smtps_ports > 0)
1982 p += sprintf(CS p, "%sSMTPS on",
1983 smtp_ports == 0 ? "" : " and for ");
1984
1985 /* Now the information about the port (and sometimes interface) */
1986
1987 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
1988 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1989 if (ipa->log)
1990 p += sprintf(CS p, "%s", ipa->log);
1991
1992 if (ipa)
1993 p += sprintf(CS p, " ...");
059ec3d9
PH
1994 }
1995
1996 log_write(0, LOG_MAIN,
1997 "exim %s daemon started: pid=%d, %s, listening for %s",
1998 version_string, getpid(), qinfo, big_buffer);
44915474
JH
1999 set_process_info("daemon(%s): %s, listening for %s",
2000 version_string, qinfo, big_buffer);
059ec3d9
PH
2001 }
2002
2003else
2004 {
44915474
JH
2005 uschar * s = *queue_name
2006 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
2007 : string_sprintf("-q%s", readconf_printtime(queue_interval));
059ec3d9 2008 log_write(0, LOG_MAIN,
44915474
JH
2009 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
2010 version_string, getpid(), s);
2011 set_process_info("daemon(%s): %s, not listening", version_string, s);
059ec3d9
PH
2012 }
2013
476be7e2
JH
2014/* Do any work it might be useful to amortize over our children
2015(eg: compile regex) */
2016
476be7e2 2017dns_pattern_init();
d85cdeb5
JH
2018smtp_deliver_init(); /* Used for callouts */
2019
2020#ifndef DISABLE_DKIM
2021 {
2022# ifdef MEASURE_TIMING
2023 struct timeval t0;
2024 gettimeofday(&t0, NULL);
2025# endif
2026 dkim_exim_init();
2027# ifdef MEASURE_TIMING
2028 report_time_since(&t0, US"dkim_exim_init (delta)");
2029# endif
2030 }
2031#endif
476be7e2
JH
2032
2033#ifdef WITH_CONTENT_SCAN
2034malware_init();
2035#endif
73ec116f
JH
2036#ifdef SUPPORT_SPF
2037spf_init();
2038#endif
059ec3d9
PH
2039
2040/* Close the log so it can be renamed and moved. In the few cases below where
2041this long-running process writes to the log (always exceptional conditions), it
2042closes the log afterwards, for the same reason. */
2043
2044log_close_all();
2045
2046DEBUG(D_any) debug_print_ids(US"daemon running with");
2047
2048/* Any messages accepted via this route are going to be SMTP. */
2049
2050smtp_input = TRUE;
2051
9f01e50d
JH
2052#ifdef MEASURE_TIMING
2053report_time_since(&timestamp_startup, US"daemon loop start"); /* testcase 0022 */
2054#endif
2055
059ec3d9
PH
2056/* Enter the never-ending loop... */
2057
2058for (;;)
2059 {
2060 #if HAVE_IPV6
2061 struct sockaddr_in6 accepted;
2062 #else
2063 struct sockaddr_in accepted;
2064 #endif
2065
cf73943b 2066 EXIM_SOCKLEN_T len;
059ec3d9
PH
2067 pid_t pid;
2068
01446a56
JH
2069 if (sigterm_seen)
2070 daemon_die(); /* Does not return */
2071
059ec3d9 2072 /* This code is placed first in the loop, so that it gets obeyed at the
9ee44efb
PP
2073 start, before the first wait, for the queue-runner case, so that the first
2074 one can be started immediately.
2075
2076 The other option is that we have an inetd wait timeout specified to -bw. */
059ec3d9
PH
2077
2078 if (sigalrm_seen)
2079 {
9ee44efb
PP
2080 if (inetd_wait_timeout > 0)
2081 {
2082 time_t resignal_interval = inetd_wait_timeout;
2083
2084 if (last_connection_time == (time_t)0)
2085 {
2086 DEBUG(D_any)
2087 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
2088 }
2089 else
2090 {
2091 time_t now = time(NULL);
2092 if (now == (time_t)-1)
2093 {
2094 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
2095 }
2096 else
2097 {
2098 if ((now - last_connection_time) >= inetd_wait_timeout)
2099 {
2100 DEBUG(D_any)
2101 debug_printf("inetd wait timeout %d expired, ending daemon\n",
2102 inetd_wait_timeout);
2103 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
2104 version_string);
2105 exit(EXIT_SUCCESS);
2106 }
2107 else
2108 {
2109 resignal_interval -= (now - last_connection_time);
2110 }
2111 }
2112 }
059ec3d9 2113
9ee44efb 2114 sigalrm_seen = FALSE;
c2a1bba0 2115 ALARM(resignal_interval);
9ee44efb 2116 }
059ec3d9 2117
9ee44efb 2118 else
059ec3d9 2119 {
ff966302
JH
2120 DEBUG(D_any) debug_printf("%s received\n",
2121#ifdef EXPERIMENTAL_QUEUE_RAMP
2122 *queuerun_msgid ? "qrun notification" :
2123#endif
2124 "SIGALRM");
8e669ac1 2125
9ee44efb
PP
2126 /* Do a full queue run in a child process, if required, unless we already
2127 have enough queue runners on the go. If we are not running as root, a
2128 re-exec is required. */
059ec3d9 2129
96c81511
JH
2130 if ( queue_interval > 0
2131 && (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
9ee44efb 2132 {
4b01271f 2133 if ((pid = exim_fork(US"queue-runner")) == 0)
9ee44efb 2134 {
9ee44efb
PP
2135 /* Disable debugging if it's required only for the daemon process. We
2136 leave the above message, because it ties up with the "child ended"
2137 debugging messages. */
059ec3d9 2138
8768d548 2139 if (f.debug_daemon) debug_selector = 0;
059ec3d9 2140
9ee44efb 2141 /* Close any open listening sockets in the child */
059ec3d9 2142
8cfc4d82
JH
2143 close_daemon_sockets(daemon_notifier_fd,
2144 listen_sockets, listen_socket_count);
059ec3d9 2145
9ee44efb 2146 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
059ec3d9 2147
9ee44efb
PP
2148 signal(SIGHUP, SIG_DFL);
2149 signal(SIGCHLD, SIG_DFL);
01446a56 2150 signal(SIGTERM, SIG_DFL);
059ec3d9 2151
9ee44efb
PP
2152 /* Re-exec if privilege has been given up, unless deliver_drop_
2153 privilege is set. Reset SIGALRM before exec(). */
4fbcfc2e 2154
9ee44efb 2155 if (geteuid() != root_uid && !deliver_drop_privilege)
4fbcfc2e 2156 {
9ee44efb
PP
2157 uschar opt[8];
2158 uschar *p = opt;
ff966302 2159 uschar *extra[7];
9ee44efb
PP
2160 int extracount = 1;
2161
2162 signal(SIGALRM, SIG_DFL);
2163 *p++ = '-';
2164 *p++ = 'q';
ff966302
JH
2165 if ( f.queue_2stage
2166#ifdef EXPERIMENTAL_QUEUE_RAMP
2167 && !*queuerun_msgid
2168#endif
2169 ) *p++ = 'q';
8768d548
JH
2170 if (f.queue_run_first_delivery) *p++ = 'i';
2171 if (f.queue_run_force) *p++ = 'f';
2172 if (f.deliver_force_thaw) *p++ = 'f';
2173 if (f.queue_run_local) *p++ = 'l';
9ee44efb 2174 *p = 0;
3f008c60 2175 extra[0] = *queue_name
e37f8a84 2176 ? string_sprintf("%sG%s", opt, queue_name) : opt;
9ee44efb 2177
ff966302
JH
2178#ifdef EXPERIMENTAL_QUEUE_RAMP
2179 if (*queuerun_msgid)
2180 {
2181 extra[extracount++] = queuerun_msgid; /* Trigger only the */
2182 extra[extracount++] = queuerun_msgid; /* one message */
2183 }
2184#endif
2185
9ee44efb
PP
2186 /* If -R or -S were on the original command line, ensure they get
2187 passed on. */
2188
e37f8a84 2189 if (deliver_selectstring)
9ee44efb 2190 {
8768d548 2191 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
9ee44efb
PP
2192 extra[extracount++] = deliver_selectstring;
2193 }
2194
e37f8a84 2195 if (deliver_selectstring_sender)
9ee44efb 2196 {
8768d548 2197 extra[extracount++] = f.deliver_selectstring_sender_regex
e37f8a84 2198 ? US"-Sr" : US"-S";
9ee44efb
PP
2199 extra[extracount++] = deliver_selectstring_sender;
2200 }
2201
2202 /* Overlay this process with a new execution. */
2203
ff966302
JH
2204 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
2205 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
9ee44efb
PP
2206
2207 /* Control never returns here. */
4fbcfc2e
PH
2208 }
2209
9ee44efb 2210 /* No need to re-exec; SIGALRM remains set to the default handler */
059ec3d9 2211
ff966302
JH
2212#ifdef EXPERIMENTAL_QUEUE_RAMP
2213 if (*queuerun_msgid)
2214 {
2215 f.queue_2stage = FALSE;
2216 queue_run(queuerun_msgid, queuerun_msgid, FALSE);
2217 }
2218 else
2219#endif
2220 queue_run(NULL, NULL, FALSE);
afd5e75f 2221 exim_underbar_exit(EXIT_SUCCESS, US"queue-runner");
059ec3d9
PH
2222 }
2223
9ee44efb 2224 if (pid < 0)
059ec3d9 2225 {
9ee44efb
PP
2226 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
2227 "process failed: %s", strerror(errno));
2228 log_close_all();
2229 }
2230 else
2231 {
d7978c0f 2232 for (int i = 0; i < local_queue_run_max; ++i)
9ee44efb
PP
2233 if (queue_pid_slots[i] <= 0)
2234 {
2235 queue_pid_slots[i] = pid;
2236 queue_run_count++;
2237 break;
2238 }
9ee44efb 2239 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
d7978c0f 2240 queue_run_count, queue_run_count == 1 ? "" : "es");
059ec3d9 2241 }
059ec3d9 2242 }
059ec3d9 2243
9ee44efb 2244 /* Reset the alarm clock */
059ec3d9 2245
9ee44efb 2246 sigalrm_seen = FALSE;
ff966302
JH
2247#ifdef EXPERIMENTAL_QUEUE_RAMP
2248 if (*queuerun_msgid)
2249 *queuerun_msgid = 0;
2250 else
2251#endif
2252 ALARM(queue_interval);
9ee44efb
PP
2253 }
2254
2255 } /* sigalrm_seen */
059ec3d9
PH
2256
2257
2258 /* Sleep till a connection happens if listening, and handle the connection if
2259 that is why we woke up. The FreeBSD operating system requires the use of
2260 select() before accept() because the latter function is not interrupted by
2261 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2262 OS do notice signals in accept() but it does no harm to have the select()
2263 in for all of them - and it won't then be a lurking problem for ports to
2264 new OS. In fact, the later addition of listening on specific interfaces only
2265 requires this way of working anyway. */
2266
8768d548 2267 if (f.daemon_listen)
059ec3d9 2268 {
d7978c0f 2269 int lcount, select_errno;
059ec3d9
PH
2270 int max_socket = 0;
2271 BOOL select_failed = FALSE;
2272 fd_set select_listen;
2273
2274 FD_ZERO(&select_listen);
ff966302
JH
2275 if (daemon_notifier_fd >= 0)
2276 FD_SET(daemon_notifier_fd, &select_listen);
d7978c0f 2277 for (int sk = 0; sk < listen_socket_count; sk++)
059ec3d9
PH
2278 {
2279 FD_SET(listen_sockets[sk], &select_listen);
2280 if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk];
2281 }
2282
2283 DEBUG(D_any) debug_printf("Listening...\n");
8e669ac1
PH
2284
2285 /* In rare cases we may have had a SIGCHLD signal in the time between
2286 setting the handler (below) and getting back here. If so, pretend that the
7d468ab8 2287 select() was interrupted so that we reap the child. This might still leave
8e669ac1 2288 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
7d468ab8
PH
2289 only to do the reaping more quickly, it shouldn't result in anything other
2290 than a delay until something else causes a wake-up. */
2291
2292 if (sigchld_seen)
2293 {
2294 lcount = -1;
8e669ac1 2295 errno = EINTR;
7d468ab8
PH
2296 }
2297 else
7d468ab8
PH
2298 lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen,
2299 NULL, NULL, NULL);
059ec3d9 2300
7d468ab8 2301 if (lcount < 0)
059ec3d9
PH
2302 {
2303 select_failed = TRUE;
2304 lcount = 1;
2305 }
8e669ac1
PH
2306
2307 /* Clean up any subprocesses that may have terminated. We need to do this
2308 here so that smtp_accept_max_per_host works when a connection to that host
2309 has completed, and we are about to accept a new one. When this code was
2310 later in the sequence, a new connection could be rejected, even though an
2311 old one had just finished. Preserve the errno from any select() failure for
bb6e88ff 2312 the use of the common select/accept error processing below. */
8e669ac1 2313
bb6e88ff
PH
2314 select_errno = errno;
2315 handle_ending_processes();
8e669ac1
PH
2316 errno = select_errno;
2317
01603eec 2318#ifndef DISABLE_TLS
b10c87b3
JH
2319 /* Create or rotate any required keys */
2320 tls_daemon_init();
2321#endif
2322
059ec3d9 2323 /* Loop for all the sockets that are currently ready to go. If select
7d468ab8
PH
2324 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2325 to use the common error code for select/accept below. */
059ec3d9
PH
2326
2327 while (lcount-- > 0)
2328 {
2329 int accept_socket = -1;
6851a9c5 2330
059ec3d9 2331 if (!select_failed)
ff966302 2332 {
ff966302
JH
2333 if ( daemon_notifier_fd >= 0
2334 && FD_ISSET(daemon_notifier_fd, &select_listen))
2335 {
2336 FD_CLR(daemon_notifier_fd, &select_listen);
2337 sigalrm_seen = daemon_notification();
2338 break; /* to top of daemon loop */
2339 }
d7978c0f 2340 for (int sk = 0; sk < listen_socket_count; sk++)
059ec3d9
PH
2341 if (FD_ISSET(listen_sockets[sk], &select_listen))
2342 {
cf73943b 2343 len = sizeof(accepted);
059ec3d9
PH
2344 accept_socket = accept(listen_sockets[sk],
2345 (struct sockaddr *)&accepted, &len);
2346 FD_CLR(listen_sockets[sk], &select_listen);
2347 break;
2348 }
ff966302 2349 }
059ec3d9
PH
2350
2351 /* If select or accept has failed and this was not caused by an
2352 interruption, log the incident and try again. With asymmetric TCP/IP
2353 routing errors such as "No route to network" have been seen here. Also
2354 "connection reset by peer" has been seen. These cannot be classed as
2355 disastrous errors, but they could fill up a lot of log. The code in smail
2356 crashes the daemon after 10 successive failures of accept, on the grounds
2357 that some OS fail continuously. Exim originally followed suit, but this
2358 appears to have caused problems. Now it just keeps going, but instead of
2359 logging each error, it batches them up when they are continuous. */
2360
2361 if (accept_socket < 0 && errno != EINTR)
2362 {
2363 if (accept_retry_count == 0)
2364 {
2365 accept_retry_errno = errno;
2366 accept_retry_select_failed = select_failed;
2367 }
2368 else
2369 {
2370 if (errno != accept_retry_errno ||
2371 select_failed != accept_retry_select_failed ||
2372 accept_retry_count >= 50)
2373 {
2374 log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0),
2375 "%d %s() failure%s: %s",
2376 accept_retry_count,
2377 accept_retry_select_failed? "select" : "accept",
2378 (accept_retry_count == 1)? "" : "s",
2379 strerror(accept_retry_errno));
2380 log_close_all();
2381 accept_retry_count = 0;
2382 accept_retry_errno = errno;
2383 accept_retry_select_failed = select_failed;
2384 }
2385 }
2386 accept_retry_count++;
2387 }
2388
2389 else
2390 {
2391 if (accept_retry_count > 0)
2392 {
2393 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2394 accept_retry_count,
2395 accept_retry_select_failed? "select" : "accept",
2396 (accept_retry_count == 1)? "" : "s",
2397 strerror(accept_retry_errno));
2398 log_close_all();
2399 accept_retry_count = 0;
2400 }
2401 }
2402
2403 /* If select/accept succeeded, deal with the connection. */
2404
2405 if (accept_socket >= 0)
9ee44efb
PP
2406 {
2407 if (inetd_wait_timeout)
2408 last_connection_time = time(NULL);
059ec3d9
PH
2409 handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,
2410 (struct sockaddr *)&accepted);
9ee44efb 2411 }
059ec3d9
PH
2412 }
2413 }
2414
2415 /* If not listening, then just sleep for the queue interval. If we woke
2416 up early the last time for some other signal, it won't matter because
2417 the alarm signal will wake at the right time. This code originally used
2418 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2419 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2420 select() can be used as an interruptible sleep() on all versions of Unix. */
2421
2422 else
2423 {
2424 struct timeval tv;
2425 tv.tv_sec = queue_interval;
2426 tv.tv_usec = 0;
2427 select(0, NULL, NULL, NULL, &tv);
8e669ac1 2428 handle_ending_processes();
059ec3d9
PH
2429 }
2430
2431 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2432 for itself, because it isn't doing the waiting itself. */
2433
2434 if (sigchld_seen)
2435 {
2436 sigchld_seen = FALSE;
7d468ab8 2437 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
059ec3d9
PH
2438 }
2439
2440 /* Handle being woken by SIGHUP. We know at this point that the result
2441 of accept() has been dealt with, so we can re-exec exim safely, first
2442 closing the listening sockets so that they can be reused. Cancel any pending
2443 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2444 that another HUP in quick succession doesn't clobber the new daemon before it
2445 gets going. All log files get closed by the close-on-exec flag; however, if
2446 the exec fails, we need to close the logs. */
2447
2448 if (sighup_seen)
2449 {
059ec3d9
PH
2450 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2451 getpid());
8cfc4d82
JH
2452 close_daemon_sockets(daemon_notifier_fd,
2453 listen_sockets, listen_socket_count);
c2a1bba0 2454 ALARM_CLR(0);
059ec3d9
PH
2455 signal(SIGHUP, SIG_IGN);
2456 sighup_argv[0] = exim_path;
2457 exim_nullstd();
2458 execv(CS exim_path, (char *const *)sighup_argv);
2459 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2460 getpid(), exim_path, strerror(errno));
2461 log_close_all();
2462 }
2463
2464 } /* End of main loop */
2465
2466/* Control never reaches here */
2467}
2468
071c51f7
JH
2469/* vi: aw ai sw=2
2470*/
059ec3d9 2471/* End of exim_daemon.c */