Close notifier socket before re-exec of daemon. Bug 2539
[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
PH
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();
370pid = fork();
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();
f3ebb786 421 exim_underbar_exit(EXIT_FAILURE);
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();
f3ebb786 508 exim_underbar_exit(EXIT_SUCCESS);
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 */
f3ebb786 536 exim_underbar_exit(EXIT_SUCCESS);
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");
f3ebb786 559 exim_underbar_exit(rc ? EXIT_FAILURE : EXIT_SUCCESS);
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
666 if ((dpid = fork()) == 0)
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();
f3ebb786 695 exim_underbar_exit(EXIT_SUCCESS);
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 {
975 uschar * s = string_sprintf("%s/%s", spool_directory, NOTIFIER_SOCKET_NAME);
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 {
984 if ((pid = fork()) == 0)
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
2f2dd3a5 1013DEBUG(D_any) debug_printf("creating notifier socket ");
ff966302 1014
ff966302 1015#ifdef SOCK_CLOEXEC
2f2dd3a5 1016if ((fd = socket(PF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0)
4a9f055c 1017 { where = US"socket"; goto bad; }
ff966302 1018#else
4a9f055c
JH
1019if ((fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0)
1020 { where = US"socket"; goto bad; }
ff966302
JH
1021(void)fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
1022#endif
1023
2f2dd3a5 1024#ifdef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
3978c243 1025sa_un.sun_path[0] = 0; /* Abstract local socket addr - Linux-specific? */
04403ab0 1026len = offsetof(struct sockaddr_un, sun_path) + 1
3978c243
JH
1027 + snprintf(sa_un.sun_path+1, sizeof(sa_un.sun_path)-1, "%s", NOTIFIER_SOCKET_NAME);
1028DEBUG(D_any) debug_printf("@%s\n", sa_un.sun_path+1);
2f2dd3a5
JH
1029#else /* filesystem-visible and persistent; will neeed removal */
1030len = offsetof(struct sockaddr_un, sun_path)
3978c243 1031 + snprintf(sa_un.sun_path, sizeof(sa_un.sun_path), "%s/%s",
2f2dd3a5 1032 spool_directory, NOTIFIER_SOCKET_NAME);
3978c243 1033DEBUG(D_any) debug_printf("%s\n", sa_un.sun_path);
2f2dd3a5 1034#endif
04403ab0 1035
3978c243 1036if (bind(fd, (const struct sockaddr *)&sa_un, len) < 0)
4a9f055c 1037 { where = US"bind"; goto bad; }
ff966302 1038
5399df80 1039#ifdef SO_PASSCRED /* Linux */
2f2dd3a5 1040if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0)
4a9f055c 1041 { where = US"SO_PASSCRED"; goto bad2; }
2f2dd3a5 1042#elif defined(LOCAL_CREDS) /* FreeBSD-ish */
4a9f055c
JH
1043if (setsockopt(fd, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
1044 { where = US"LOCAL_CREDS"; goto bad2; }
2f2dd3a5 1045#endif
ff966302
JH
1046
1047/* debug_printf("%s: fd %d\n", __FUNCTION__, fd); */
1048daemon_notifier_fd = fd;
1049return;
1050
4a9f055c
JH
1051bad2:
1052#ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1053 Uunlink(sa_un.sun_path);
1054#endif
ff966302 1055bad:
4a9f055c 1056 log_write(0, LOG_MAIN|LOG_PANIC, "%s %s: %s",
ff966302 1057 __FUNCTION__, where, strerror(errno));
4a9f055c
JH
1058 close(fd);
1059 return;
ff966302
JH
1060}
1061
1062
1063static uschar queuerun_msgid[MESSAGE_ID_LENGTH+1];
1064
1065/* Return TRUE if a sigalrm should be emulated */
1066static BOOL
1067daemon_notification(void)
1068{
1069uschar buf[256], cbuf[256];
3978c243 1070struct sockaddr_un sa_un;
017de05c 1071struct iovec iov = {.iov_base = buf, .iov_len = sizeof(buf)-1};
3978c243
JH
1072struct msghdr msg = { .msg_name = &sa_un,
1073 .msg_namelen = sizeof(sa_un),
ff966302
JH
1074 .msg_iov = &iov,
1075 .msg_iovlen = 1,
1076 .msg_control = cbuf,
1077 .msg_controllen = sizeof(cbuf)
1078 };
1079ssize_t sz;
1080struct cmsghdr * cp;
1081
1082buf[sizeof(buf)-1] = 0;
1083if ((sz = recvmsg(daemon_notifier_fd, &msg, 0)) <= 0) return FALSE;
1084if (sz >= sizeof(buf)) return FALSE;
1085
04403ab0
JH
1086#ifdef notdef
1087debug_printf("addrlen %d\n", msg.msg_namelen);
1088#endif
2f2dd3a5 1089DEBUG(D_queue_run) debug_printf("%s from addr '%s%.*s'\n", __FUNCTION__,
3978c243
JH
1090 *sa_un.sun_path ? "" : "@",
1091 (int)msg.msg_namelen - (*sa_un.sun_path ? 0 : 1),
1092 sa_un.sun_path + (*sa_un.sun_path ? 0 : 1));
04403ab0
JH
1093
1094/* Refuse to handle the item unless the peer has good credentials */
f254e592
JH
1095#ifdef SCM_CREDENTIALS
1096# define EXIM_SCM_CR_TYPE SCM_CREDENTIALS
5399df80 1097#elif defined(LOCAL_CREDS) && defined(SCM_CREDS)
f254e592
JH
1098# define EXIM_SCM_CR_TYPE SCM_CREDS
1099#else
2f2dd3a5
JH
1100 /* The OS has no way to get the creds of the caller (for a unix/datagram socket.
1101 Punt; don't try to check. */
f254e592 1102#endif
04403ab0 1103
2f2dd3a5 1104#ifdef EXIM_SCM_CR_TYPE
ff966302
JH
1105for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg);
1106 cp;
1107 cp = CMSG_NXTHDR(&msg, cp))
f254e592 1108 if (cp->cmsg_level == SOL_SOCKET && cp->cmsg_type == EXIM_SCM_CR_TYPE)
ff966302 1109 {
2f2dd3a5 1110# ifdef SCM_CREDENTIALS /* Linux */
ff966302
JH
1111 struct ucred * cr = (struct ucred *) CMSG_DATA(cp);
1112 if (cr->uid && cr->uid != exim_uid)
1113 {
1114 DEBUG(D_queue_run) debug_printf("%s: sender creds pid %d uid %d gid %d\n",
1115 __FUNCTION__, (int)cr->pid, (int)cr->uid, (int)cr->gid);
1116 return FALSE;
2f2dd3a5
JH
1117 }
1118# elif defined(LOCAL_CREDS) /* BSD-ish */
5399df80
JH
1119 struct sockcred * cr = (struct sockcred *) CMSG_DATA(cp);
1120 if (cr->sc_uid && cr->sc_uid != exim_uid)
f254e592 1121 {
5399df80
JH
1122 DEBUG(D_queue_run) debug_printf("%s: sender creds pid ??? uid %d gid %d\n",
1123 __FUNCTION__, (int)cr->sc_uid, (int)cr->sc_gid);
f254e592 1124 return FALSE;
ff966302 1125 }
2f2dd3a5 1126# endif
ff966302
JH
1127 break;
1128 }
2f2dd3a5 1129#endif
ff966302
JH
1130
1131buf[sz] = 0;
1132switch (buf[0])
1133 {
4c2efd7a 1134#ifdef EXPERIMENTAL_QUEUE_RAMP
ff966302
JH
1135 case NOTIFY_MSG_QRUN:
1136 /* this should be a message_id */
1137 DEBUG(D_queue_run)
1138 debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1);
1139 memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1);
1140 return TRUE;
4c2efd7a 1141#endif /*EXPERIMENTAL_QUEUE_RAMP*/
04403ab0
JH
1142
1143 case NOTIFY_QUEUE_SIZE_REQ:
1144 {
1145 uschar buf[16];
1146 int len = snprintf(CS buf, sizeof(buf), "%u", queue_count_cached());
1147
1148 DEBUG(D_queue_run)
1149 debug_printf("%s: queue size request: %s\n", __FUNCTION__, buf);
1150
f254e592 1151 if (sendto(daemon_notifier_fd, buf, len, 0,
3978c243 1152 (const struct sockaddr *)&sa_un, msg.msg_namelen) < 0)
04403ab0
JH
1153 log_write(0, LOG_MAIN|LOG_PANIC,
1154 "%s: sendto: %s\n", __FUNCTION__, strerror(errno));
1155 return FALSE;
1156 }
ff966302
JH
1157 }
1158return FALSE;
1159}
ff966302
JH
1160
1161
059ec3d9
PH
1162/*************************************************
1163* Exim Daemon Mainline *
1164*************************************************/
1165
1166/* The daemon can do two jobs, either of which is optional:
1167
1168(1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1169each one. This is requested by the -bd option, with -oX specifying the SMTP
1170port on which to listen (for testing).
1171
1172(2) Spawns a queue-running process every so often. This is controlled by the
1173-q option with a an interval time. (If no time is given, a single queue run
1174is done from the main function, and control doesn't get here.)
1175
1176Root privilege is required in order to attach to port 25. Some systems require
1177it when calling socket() rather than bind(). To cope with all cases, we run as
1178root for both socket() and bind(). Some systems also require root in order to
1179write to the pid file directory. This function must therefore be called as root
1180if it is to work properly in all circumstances. Once the socket is bound and
1181the pid file written, root privilege is given up if there is an exim uid.
1182
1183There are no arguments to this function, and it never returns. */
1184
1185void
1186daemon_go(void)
1187{
ebeaf996 1188struct passwd *pw;
059ec3d9
PH
1189int *listen_sockets = NULL;
1190int listen_socket_count = 0;
1191ip_address_item *addresses = NULL;
9ee44efb 1192time_t last_connection_time = (time_t)0;
4dc2379a 1193int local_queue_run_max = atoi(CS expand_string(queue_run_max));
059ec3d9
PH
1194
1195/* If any debugging options are set, turn on the D_pid bit so that all
1196debugging lines get the pid added. */
1197
1198DEBUG(D_any|D_v) debug_selector |= D_pid;
1199
8768d548 1200if (f.inetd_wait_mode)
9ee44efb 1201 {
9ee44efb 1202 listen_socket_count = 1;
f3ebb786 1203 listen_sockets = store_get(sizeof(int), FALSE);
9ee44efb
PP
1204 (void) close(3);
1205 if (dup2(0, 3) == -1)
9ee44efb
PP
1206 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1207 "failed to dup inetd socket safely away: %s", strerror(errno));
d4ff61d1 1208
9ee44efb
PP
1209 listen_sockets[0] = 3;
1210 (void) close(0);
1211 (void) close(1);
1212 (void) close(2);
1213 exim_nullstd();
1214
1215 if (debug_file == stderr)
1216 {
1217 /* need a call to log_write before call to open debug_file, so that
1218 log.c:file_path has been initialised. This is unfortunate. */
1219 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1220
1221 fclose(debug_file);
1222 debug_file = NULL;
1223 exim_nullstd(); /* re-open fd2 after we just closed it again */
1224 debug_logging_activate(US"-wait", NULL);
1225 }
1226
1227 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1228
1229 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1230 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1231
d4ff61d1
JH
1232 if (tcp_nodelay)
1233 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1234 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1235 strerror(errno));
9ee44efb
PP
1236 }
1237
1238
8768d548 1239if (f.inetd_wait_mode || f.daemon_listen)
9ee44efb
PP
1240 {
1241 /* If any option requiring a load average to be available during the
1242 reception of a message is set, call os_getloadavg() while we are root
1243 for those OS for which this is necessary the first time it is called (in
1244 order to perform an "open" on the kernel memory file). */
1245
1246 #ifdef LOAD_AVG_NEEDS_ROOT
1247 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1248 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1249 (void)os_getloadavg();
1250 #endif
1251 }
1252
059ec3d9
PH
1253
1254/* Do the preparation for setting up a listener on one or more interfaces, and
1255possible on various ports. This is controlled by the combination of
1256local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1257(which is a list of default ports to use for those items in local_interfaces
1258that do not specify a port). The -oX command line option can be used to
1259override one or both of these options.
1260
1261If local_interfaces is not set, the default is to listen on all interfaces.
1262When it is set, it can include "all IPvx interfaces" as an item. This is useful
1263when different ports are in use.
1264
1265It turns out that listening on all interfaces is messy in an IPv6 world,
1266because several different implementation approaches have been taken. This code
1267is now supposed to work with all of them. The point of difference is whether an
1268IPv6 socket that is listening on all interfaces will receive incoming IPv4
1269calls or not. We also have to cope with the case when IPv6 libraries exist, but
1270there is no IPv6 support in the kernel.
1271
1272. On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1273 addresses. However, if an IPv4 socket is also listening on all interfaces,
1274 calls are directed to the appropriate socket.
1275
1276. On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1277 give them as mapped addresses, but an attempt also to listen on an IPv4
1278 socket on all interfaces causes an error.
1279
1280. On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1281 two sockets if you want to accept both kinds of call.
1282
1283. FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1284 can be turned off, to make it behave like the versions of Linux described
1285 above.
1286
1287. I heard a report that the USAGI IPv6 stack for Linux has implemented
1288 IPV6_V6ONLY.
1289
1290So, what we do when IPv6 is supported is as follows:
1291
1292 (1) After it is set up, the list of interfaces is scanned for wildcard
1293 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1294 port, the list is re-arranged so that they are together, with the IPv6
1295 wildcard first.
1296
1297 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1298 carry on if an IPv4 wildcard socket for the same port follows later in the
1299 list. This allows Exim to carry on in the case when the kernel has no IPv6
1300 support.
1301
1302 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1303 option is defined. However, if setting fails, carry on regardless (but log
1304 the incident).
1305
1306 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1307 error.
1308
1309 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1310 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1311 port (which must have succeeded or we wouldn't have got this far), we
1312 assume we are in the situation where just a single socket is permitted,
1313 and ignore the error.
1314
1315Phew!
1316
1317The preparation code decodes options and sets up the relevant data. We do this
1318first, so that we can return non-zero if there are any syntax errors, and also
1319write to stderr. */
1320
8768d548 1321if (f.daemon_listen && !f.inetd_wait_mode)
059ec3d9
PH
1322 {
1323 int *default_smtp_port;
1324 int sep;
1325 int pct = 0;
1326 uschar *s;
55414b25 1327 const uschar * list;
059ec3d9
PH
1328 uschar *local_iface_source = US"local_interfaces";
1329 ip_address_item *ipa;
1330 ip_address_item **pipa;
1331
059ec3d9
PH
1332 /* If -oX was used, disable the writing of a pid file unless -oP was
1333 explicitly used to force it. Then scan the string given to -oX. Any items
1334 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1335 Any other items are used to override local_interfaces. */
1336
acec9514 1337 if (override_local_interfaces)
059ec3d9 1338 {
acec9514
JH
1339 gstring * new_smtp_port = NULL;
1340 gstring * new_local_interfaces = NULL;
059ec3d9 1341
01446a56 1342 if (!override_pid_file_path) write_pid = FALSE;
059ec3d9
PH
1343
1344 list = override_local_interfaces;
1345 sep = 0;
55414b25 1346 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
059ec3d9
PH
1347 {
1348 uschar joinstr[4];
01446a56 1349 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
059ec3d9 1350
acec9514 1351 if (!*gp)
059ec3d9
PH
1352 {
1353 joinstr[0] = sep;
1354 joinstr[1] = ' ';
acec9514 1355 *gp = string_catn(*gp, US"<", 1);
059ec3d9
PH
1356 }
1357
acec9514
JH
1358 *gp = string_catn(*gp, joinstr, 2);
1359 *gp = string_cat (*gp, s);
059ec3d9
PH
1360 }
1361
acec9514 1362 if (new_smtp_port)
059ec3d9 1363 {
acec9514 1364 daemon_smtp_port = string_from_gstring(new_smtp_port);
059ec3d9
PH
1365 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1366 daemon_smtp_port);
1367 }
1368
acec9514 1369 if (new_local_interfaces)
059ec3d9 1370 {
acec9514 1371 local_interfaces = string_from_gstring(new_local_interfaces);
059ec3d9
PH
1372 local_iface_source = US"-oX data";
1373 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1374 local_interfaces);
1375 }
1376 }
1377
1378 /* Create a list of default SMTP ports, to be used if local_interfaces
4c04137d 1379 contains entries without explicit ports. First count the number of ports, then
059ec3d9
PH
1380 build a translated list in a vector. */
1381
1382 list = daemon_smtp_port;
1383 sep = 0;
55414b25 1384 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
059ec3d9 1385 pct++;
f3ebb786 1386 default_smtp_port = store_get((pct+1) * sizeof(int), FALSE);
059ec3d9
PH
1387 list = daemon_smtp_port;
1388 sep = 0;
1389 for (pct = 0;
55414b25 1390 (s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size));
059ec3d9
PH
1391 pct++)
1392 {
1393 if (isdigit(*s))
1394 {
1395 uschar *end;
1396 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1397 if (end != s + Ustrlen(s))
1398 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1399 }
1400 else
1401 {
1402 struct servent *smtp_service = getservbyname(CS s, "tcp");
071c51f7 1403 if (!smtp_service)
059ec3d9
PH
1404 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1405 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1406 }
1407 }
1408 default_smtp_port[pct] = 0;
1409
071c51f7
JH
1410 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1411
1412 list = tls_in.on_connect_ports;
1413 sep = 0;
1414 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1415 if (!isdigit(*s))
1416 {
acec9514 1417 gstring * g = NULL;
4226691b 1418
071c51f7
JH
1419 list = tls_in.on_connect_ports;
1420 tls_in.on_connect_ports = NULL;
1421 sep = 0;
1422 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1423 {
1424 if (!isdigit(*s))
1425 {
4226691b 1426 struct servent * smtp_service = getservbyname(CS s, "tcp");
071c51f7
JH
1427 if (!smtp_service)
1428 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
4226691b 1429 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
071c51f7 1430 }
acec9514 1431 g = string_append_listele(g, ':', s);
071c51f7 1432 }
acec9514
JH
1433 if (g)
1434 tls_in.on_connect_ports = g->s;
071c51f7
JH
1435 break;
1436 }
1437
059ec3d9
PH
1438 /* Create the list of local interfaces, possibly with ports included. This
1439 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1440 values are converted below. */
1441
1442 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1443
1444 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1445 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1446 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1447 anyway, but we need to know which are the wildcard addresses, and the shorter
1448 strings are neater.
1449
1450 In the same scan, fill in missing port numbers from the default list. When
1451 there is more than one item in the list, extra items are created. */
1452
b891534f 1453 for (ipa = addresses; ipa; ipa = ipa->next)
059ec3d9 1454 {
b891534f
JH
1455 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1456 ipa->address[0] = 0;
059ec3d9
PH
1457 else if (Ustrcmp(ipa->address, "::0") == 0)
1458 {
1459 ipa->address[0] = ':';
1460 ipa->address[1] = 0;
1461 }
1462
1463 if (ipa->port > 0) continue;
1464
1465 if (daemon_smtp_port[0] <= 0)
1466 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1467 "%s and daemon_smtp_port is unset; cannot start daemon",
b891534f
JH
1468 ipa->address[0] == 0 ? US"\"all IPv4\"" :
1469 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
1470
059ec3d9 1471 ipa->port = default_smtp_port[0];
d7978c0f 1472 for (int i = 1; default_smtp_port[i] > 0; i++)
059ec3d9 1473 {
f3ebb786 1474 ip_address_item *new = store_get(sizeof(ip_address_item), FALSE);
b891534f 1475
059ec3d9
PH
1476 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1477 new->port = default_smtp_port[i];
1478 new->next = ipa->next;
1479 ipa->next = new;
1480 ipa = new;
1481 }
1482 }
1483
1484 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1485 wildcard for the same port, ensure that (a) they are together and (b) the
1486 IPv6 address comes first. This makes handling the messy features easier, and
1487 also simplifies the construction of the "daemon started" log line. */
1488
1489 pipa = &addresses;
b891534f 1490 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
059ec3d9
PH
1491 {
1492 ip_address_item *ipa2;
1493
1494 /* Handle an IPv4 wildcard */
1495
1496 if (ipa->address[0] == 0)
b891534f 1497 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
059ec3d9
PH
1498 {
1499 ip_address_item *ipa3 = ipa2->next;
1500 if (ipa3->address[0] == ':' &&
1501 ipa3->address[1] == 0 &&
1502 ipa3->port == ipa->port)
1503 {
1504 ipa2->next = ipa3->next;
1505 ipa3->next = ipa;
1506 *pipa = ipa3;
1507 break;
1508 }
1509 }
059ec3d9
PH
1510
1511 /* Handle an IPv6 wildcard. */
1512
1513 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
b891534f 1514 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
059ec3d9
PH
1515 {
1516 ip_address_item *ipa3 = ipa2->next;
1517 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1518 {
1519 ipa2->next = ipa3->next;
1520 ipa3->next = ipa->next;
1521 ipa->next = ipa3;
1522 ipa = ipa3;
1523 break;
1524 }
1525 }
059ec3d9
PH
1526 }
1527
1528 /* Get a vector to remember all the sockets in */
1529
b891534f 1530 for (ipa = addresses; ipa; ipa = ipa->next)
059ec3d9 1531 listen_socket_count++;
f3ebb786 1532 listen_sockets = store_get(sizeof(int) * listen_socket_count, FALSE);
059ec3d9 1533
9ee44efb
PP
1534 } /* daemon_listen but not inetd_wait_mode */
1535
8768d548 1536if (f.daemon_listen)
9ee44efb
PP
1537 {
1538
059ec3d9
PH
1539 /* Do a sanity check on the max connects value just to save us from getting
1540 a huge amount of store. */
1541
1542 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1543
1544 /* There's no point setting smtp_accept_queue unless it is less than the max
1545 connects limit. The configuration reader ensures that the max is set if the
1546 queue-only option is set. */
1547
1548 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1549
1550 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1551 track of them for total number and queue/host limits. */
1552
1553 if (smtp_accept_max > 0)
1554 {
f3ebb786 1555 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), FALSE);
d7978c0f 1556 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
059ec3d9
PH
1557 }
1558 }
1559
76a2d7ba
PH
1560/* The variable background_daemon is always false when debugging, but
1561can also be forced false in order to keep a non-debugging daemon in the
1562foreground. If background_daemon is true, close all open file descriptors that
9ee44efb
PP
1563we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1564do this for inetd_wait mode.
76a2d7ba
PH
1565
1566This is protection against any called functions (in libraries, or in
1567Perl, or whatever) that think they can write to stderr (or stdout). Before this
1568was added, it was quite likely that an SMTP connection would use one of these
1569file descriptors, in which case writing random stuff to it caused chaos.
1570
1571Then disconnect from the controlling terminal, Most modern Unixes seem to have
1572setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1573setsid() can be #defined as a no-op, or as something else. */
059ec3d9 1574
8768d548 1575if (f.background_daemon || f.inetd_wait_mode)
059ec3d9 1576 {
76a2d7ba
PH
1577 log_close_all(); /* Just in case anything was logged earlier */
1578 search_tidyup(); /* Just in case any were used in reading the config. */
f1e894f3
PH
1579 (void)close(0); /* Get rid of stdin/stdout/stderr */
1580 (void)close(1);
1581 (void)close(2);
8e669ac1 1582 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
059ec3d9 1583 log_stderr = NULL; /* So no attempt to copy paniclog output */
9ee44efb 1584 }
059ec3d9 1585
8768d548 1586if (f.background_daemon)
9ee44efb 1587 {
059ec3d9 1588 /* If the parent process of this one has pid == 1, we are re-initializing the
8e669ac1 1589 daemon as the result of a SIGHUP. In this case, there is no need to do
76a2d7ba
PH
1590 anything, because the controlling terminal has long gone. Otherwise, fork, in
1591 case current process is a process group leader (see 'man setsid' for an
1592 explanation) before calling setsid(). */
059ec3d9
PH
1593
1594 if (getppid() != 1)
1595 {
1596 pid_t pid = fork();
1597 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1598 "fork() failed when starting daemon: %s", strerror(errno));
1599 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1600 (void)setsid(); /* release controlling terminal */
1601 }
1602 }
1603
1604/* We are now in the disconnected, daemon process (unless debugging). Set up
1605the listening sockets if required. */
1606
4c2efd7a 1607daemon_notifier_socket();
ff966302 1608
8768d548 1609if (f.daemon_listen && !f.inetd_wait_mode)
059ec3d9
PH
1610 {
1611 int sk;
059ec3d9
PH
1612 ip_address_item *ipa;
1613
1614 /* For each IP address, create a socket, bind it to the appropriate port, and
1615 start listening. See comments above about IPv6 sockets that may or may not
1616 accept IPv4 calls when listening on all interfaces. We also have to cope with
1617 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1618 listening, provided a wildcard IPv4 socket for the same port follows. */
1619
1620 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1621 {
1622 BOOL wildcard;
1623 ip_address_item *ipa2;
059ec3d9
PH
1624 int af;
1625
1626 if (Ustrchr(ipa->address, ':') != NULL)
1627 {
1628 af = AF_INET6;
1629 wildcard = ipa->address[1] == 0;
1630 }
1631 else
1632 {
1633 af = AF_INET;
1634 wildcard = ipa->address[0] == 0;
1635 }
1636
96f5fe4c 1637 if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0)
059ec3d9
PH
1638 {
1639 if (check_special_case(0, addresses, ipa, FALSE))
1640 {
1641 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1642 "listening (%s): will use IPv4", strerror(errno));
1643 goto SKIP_SOCKET;
1644 }
1645 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1646 (af == AF_INET6)? '6' : '4', strerror(errno));
1647 }
1648
1649 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1650 available. Just log failure (can get protocol not available, just like
1651 socket creation can). */
1652
b891534f 1653#ifdef IPV6_V6ONLY
059ec3d9 1654 if (af == AF_INET6 && wildcard &&
5903c6ff 1655 setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, CS (&on),
059ec3d9
PH
1656 sizeof(on)) < 0)
1657 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1658 "socket failed (%s): carrying on without it", strerror(errno));
b891534f 1659#endif /* IPV6_V6ONLY */
059ec3d9
PH
1660
1661 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1662 is being handled. Without this, a connection will prevent reuse of the
1663 smtp port for listening. */
1664
1665 if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR,
5903c6ff 1666 US (&on), sizeof(on)) < 0)
059ec3d9
PH
1667 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1668 "failed when starting daemon: %s", strerror(errno));
1669
1670 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1671 disable this because it breaks some broken clients. */
1672
1673 if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY,
5903c6ff 1674 US (&on), sizeof(on));
059ec3d9
PH
1675
1676 /* Now bind the socket to the required port; if Exim is being restarted
1677 it may not always be possible to bind immediately, even with SO_REUSEADDR
1678 set, so try 10 times, waiting between each try. After 10 failures, we give
1679 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1680 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1681 address for the same port, ignore the error on the grounds that we must be
1682 in a system where the IPv6 socket accepts both kinds of call. This is
1683 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1684 listen() stage instead. */
1685
6af7e591 1686#ifdef TCP_FASTOPEN
8768d548 1687 f.tcp_fastopen_ok = TRUE;
6af7e591 1688#endif
059ec3d9
PH
1689 for(;;)
1690 {
1691 uschar *msg, *addr;
1692 if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break;
1693 if (check_special_case(errno, addresses, ipa, TRUE))
1694 {
1695 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1696 "listen() success; EADDRINUSE ignored\n");
f1e894f3 1697 (void)close(listen_sockets[sk]);
059ec3d9
PH
1698 goto SKIP_SOCKET;
1699 }
1700 msg = US strerror(errno);
b891534f
JH
1701 addr = wildcard
1702 ? af == AF_INET6
1703 ? US"(any IPv6)"
1704 : US"(any IPv4)"
1705 : ipa->address;
4aee0225 1706 if (daemon_startup_retries <= 0)
059ec3d9
PH
1707 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1708 "socket bind() to port %d for address %s failed: %s: "
1709 "daemon abandoned", ipa->port, addr, msg);
1710 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
4aee0225
PH
1711 "failed: %s: waiting %s before trying again (%d more %s)",
1712 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1713 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1714 daemon_startup_retries--;
1715 sleep(daemon_startup_sleep);
059ec3d9
PH
1716 }
1717
1718 DEBUG(D_any)
059ec3d9
PH
1719 if (wildcard)
1720 debug_printf("listening on all interfaces (IPv%c) port %d\n",
fb05276a 1721 af == AF_INET6 ? '6' : '4', ipa->port);
059ec3d9
PH
1722 else
1723 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
fb05276a 1724
b536a578 1725#if defined(TCP_FASTOPEN) && !defined(__APPLE__)
590faf89
JH
1726 if ( f.tcp_fastopen_ok
1727 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
4670e9d3 1728 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
6af7e591 1729 {
a23ff3b4 1730 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
8768d548 1731 f.tcp_fastopen_ok = FALSE;
6af7e591 1732 }
fb05276a 1733#endif
059ec3d9
PH
1734
1735 /* Start listening on the bound socket, establishing the maximum backlog of
1736 connections that is allowed. On success, continue to the next address. */
1737
b536a578
JH
1738 if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0)
1739 {
1740#if defined(TCP_FASTOPEN) && defined(__APPLE__)
1741 if ( f.tcp_fastopen_ok
1742 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1743 &on, sizeof(on)))
1744 {
1745 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1746 f.tcp_fastopen_ok = FALSE;
1747 }
1748#endif
1749 continue;
1750 }
059ec3d9
PH
1751
1752 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1753 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1754 and there was a previous successful IPv6 wildcard listen on the same port,
1755 we want to ignore the error on the grounds that we must be in a system
1756 where the IPv6 socket accepts both kinds of call. */
1757
1758 if (!check_special_case(errno, addresses, ipa, TRUE))
1759 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
fb05276a
JH
1760 wildcard
1761 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
059ec3d9
PH
1762 strerror(errno));
1763
1764 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1765 "listen() success; EADDRINUSE ignored\n");
f1e894f3 1766 (void)close(listen_sockets[sk]);
059ec3d9
PH
1767
1768 /* Come here if there has been a problem with the socket which we
1769 are going to ignore. We remove the address from the chain, and back up the
1770 counts. */
1771
b891534f 1772 SKIP_SOCKET:
059ec3d9
PH
1773 sk--; /* Back up the count */
1774 listen_socket_count--; /* Reduce the total */
1775 if (ipa == addresses) addresses = ipa->next; else
1776 {
1777 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1778 ipa2->next = ipa->next;
1779 ipa = ipa2;
1780 }
1781 } /* End of bind/listen loop for each address */
1782 } /* End of setup for listening */
1783
1784
1785/* If we are not listening, we want to write a pid file only if -oP was
1786explicitly given. */
1787
b891534f
JH
1788else if (!override_pid_file_path)
1789 write_pid = FALSE;
059ec3d9
PH
1790
1791/* Write the pid to a known file for assistance in identification, if required.
1792We do this before giving up root privilege, because on some systems it is
1793necessary to be root in order to write into the pid file directory. There's
1794nothing to stop multiple daemons running, as long as no more than one listens
1795on a given TCP/IP port on the same interface(s). However, in these
1796circumstances it gets far too complicated to mess with pid file names
1797automatically. Consequently, Exim 4 writes a pid file only
1798
1799 (a) When running in the test harness, or
1800 (b) When -bd is used and -oX is not used, or
1801 (c) When -oP is used to supply a path.
1802
1803The variable daemon_write_pid is used to control this. */
1804
8768d548 1805if (f.running_in_test_harness || write_pid)
059ec3d9
PH
1806 {
1807 FILE *f;
1808
01446a56 1809 set_pid_file_path();
b891534f 1810 if ((f = modefopen(pid_file_path, "wb", 0644)))
059ec3d9 1811 {
ff790e47 1812 (void)fprintf(f, "%d\n", (int)getpid());
ff790e47 1813 (void)fclose(f);
059ec3d9
PH
1814 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1815 }
1816 else
059ec3d9
PH
1817 DEBUG(D_any)
1818 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
1819 pid_file_path));
059ec3d9
PH
1820 }
1821
1822/* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1823
1824sighup_seen = FALSE;
1825signal(SIGHUP, sighup_handler);
1826
1827/* Give up root privilege at this point (assuming that exim_uid and exim_gid
1828are not root). The third argument controls the running of initgroups().
1829Normally we do this, in order to set up the groups for the Exim user. However,
1830if we are not root at this time - some odd installations run that way - we
1831cannot do this. */
1832
1833exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1834
ebeaf996
PH
1835/* Update the originator_xxx fields so that received messages as listed as
1836coming from Exim, not whoever started the daemon. */
1837
1838originator_uid = exim_uid;
1839originator_gid = exim_gid;
f3ebb786
JH
1840originator_login = (pw = getpwuid(exim_uid))
1841 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
ebeaf996 1842
059ec3d9
PH
1843/* Get somewhere to keep the list of queue-runner pids if we are keeping track
1844of them (and also if we are doing queue runs). */
1845
0cd5fd23 1846if (queue_interval > 0 && local_queue_run_max > 0)
059ec3d9 1847 {
f3ebb786 1848 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t), FALSE);
d7978c0f 1849 for (int i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
059ec3d9
PH
1850 }
1851
01446a56
JH
1852/* Set up the handler for termination of child processes, and the one
1853telling us to die. */
059ec3d9
PH
1854
1855sigchld_seen = FALSE;
7d468ab8 1856os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
059ec3d9 1857
01446a56
JH
1858sigterm_seen = FALSE;
1859os_non_restarting_signal(SIGTERM, main_sigterm_handler);
1860
059ec3d9
PH
1861/* If we are to run the queue periodically, pretend the alarm has just gone
1862off. This will cause the first queue-runner to get kicked off straight away. */
1863
1864sigalrm_seen = (queue_interval > 0);
1865
1866/* Log the start up of a daemon - at least one of listening or queue running
1867must be set up. */
1868
8768d548 1869if (f.inetd_wait_mode)
9ee44efb
PP
1870 {
1871 uschar *p = big_buffer;
1872
1873 if (inetd_wait_timeout >= 0)
1874 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
1875 else
1876 sprintf(CS p, "with no wait timeout");
1877
1878 log_write(0, LOG_MAIN,
1879 "exim %s daemon started: pid=%d, launched with listening socket, %s",
1880 version_string, getpid(), big_buffer);
2f21487f 1881 set_process_info("daemon(%s): pre-listening socket", version_string);
9ee44efb
PP
1882
1883 /* set up the timeout logic */
ff966302 1884 sigalrm_seen = TRUE;
9ee44efb
PP
1885 }
1886
8768d548 1887else if (f.daemon_listen)
059ec3d9 1888 {
059ec3d9
PH
1889 int smtp_ports = 0;
1890 int smtps_ports = 0;
254f38d1
JH
1891 ip_address_item * ipa;
1892 uschar * p;
e37f8a84
JH
1893 uschar * qinfo = queue_interval > 0
1894 ? string_sprintf("-q%s", readconf_printtime(queue_interval))
1895 : US"no queue runs";
059ec3d9
PH
1896
1897 /* Build a list of listening addresses in big_buffer, but limit it to 10
1898 items. The style is for backwards compatibility.
1899
1900 It is now possible to have some ports listening for SMTPS (the old,
1901 deprecated protocol that starts TLS without using STARTTLS), and others
1902 listening for standard SMTP. Keep their listings separate. */
1903
254f38d1 1904 for (int j = 0, i; j < 2; j++)
059ec3d9 1905 {
e37f8a84 1906 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
b891534f
JH
1907 {
1908 /* First time round, look for SMTP ports; second time round, look for
254f38d1 1909 SMTPS ports. Build IP+port strings. */
b891534f
JH
1910
1911 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1912 {
1913 if (j == 0)
254f38d1 1914 smtp_ports++;
b891534f 1915 else
254f38d1 1916 smtps_ports++;
b891534f
JH
1917
1918 /* Now the information about the port (and sometimes interface) */
1919
1920 if (ipa->address[0] == ':' && ipa->address[1] == 0)
e4d0fc93 1921 { /* v6 wildcard */
b891534f
JH
1922 if (ipa->next && ipa->next->address[0] == 0 &&
1923 ipa->next->port == ipa->port)
1924 {
254f38d1
JH
1925 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
1926 (ipa = ipa->next)->log = NULL;
b891534f
JH
1927 }
1928 else if (ipa->v6_include_v4)
254f38d1 1929 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
b891534f 1930 else
254f38d1 1931 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
b891534f 1932 }
e4d0fc93 1933 else if (ipa->address[0] == 0) /* v4 wildcard */
254f38d1 1934 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
e4d0fc93 1935 else /* check for previously-seen IP */
b891534f 1936 {
254f38d1 1937 ip_address_item * i2;
e4d0fc93
JH
1938 for (i2 = addresses; i2 != ipa; i2 = i2->next)
1939 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
1940 && Ustrcmp(ipa->address, i2->address) == 0
1941 )
1942 { /* found; append port to list */
254f38d1
JH
1943 for (p = i2->log; *p; ) p++; /* end of existing string */
1944 if (*--p == '}') *p = '\0'; /* drop EOL */
1945 while (isdigit(*--p)) ; /* char before port */
1946
1947 i2->log = *p == ':' /* no list yet? */
1948 ? string_sprintf("%.*s{%s,%d}",
1949 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
1950 : string_sprintf("%s,%d}", i2->log, ipa->port);
1951 ipa->log = NULL;
e4d0fc93
JH
1952 break;
1953 }
1954 if (i2 == ipa) /* first-time IP */
254f38d1 1955 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
b891534f 1956 }
b891534f
JH
1957 }
1958 }
254f38d1 1959 }
059ec3d9 1960
254f38d1
JH
1961 p = big_buffer;
1962 for (int j = 0, i; j < 2; j++)
1963 {
1964 /* First time round, look for SMTP ports; second time round, look for
1965 SMTPS ports. For the first one of each, insert leading text. */
1966
1967 if (j == 0)
059ec3d9 1968 {
254f38d1
JH
1969 if (smtp_ports > 0)
1970 p += sprintf(CS p, "SMTP on");
059ec3d9 1971 }
254f38d1
JH
1972 else
1973 if (smtps_ports > 0)
1974 p += sprintf(CS p, "%sSMTPS on",
1975 smtp_ports == 0 ? "" : " and for ");
1976
1977 /* Now the information about the port (and sometimes interface) */
1978
1979 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
1980 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1981 if (ipa->log)
1982 p += sprintf(CS p, "%s", ipa->log);
1983
1984 if (ipa)
1985 p += sprintf(CS p, " ...");
059ec3d9
PH
1986 }
1987
1988 log_write(0, LOG_MAIN,
1989 "exim %s daemon started: pid=%d, %s, listening for %s",
1990 version_string, getpid(), qinfo, big_buffer);
44915474
JH
1991 set_process_info("daemon(%s): %s, listening for %s",
1992 version_string, qinfo, big_buffer);
059ec3d9
PH
1993 }
1994
1995else
1996 {
44915474
JH
1997 uschar * s = *queue_name
1998 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
1999 : string_sprintf("-q%s", readconf_printtime(queue_interval));
059ec3d9 2000 log_write(0, LOG_MAIN,
44915474
JH
2001 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
2002 version_string, getpid(), s);
2003 set_process_info("daemon(%s): %s, not listening", version_string, s);
059ec3d9
PH
2004 }
2005
476be7e2
JH
2006/* Do any work it might be useful to amortize over our children
2007(eg: compile regex) */
2008
476be7e2 2009dns_pattern_init();
d85cdeb5
JH
2010smtp_deliver_init(); /* Used for callouts */
2011
2012#ifndef DISABLE_DKIM
2013 {
2014# ifdef MEASURE_TIMING
2015 struct timeval t0;
2016 gettimeofday(&t0, NULL);
2017# endif
2018 dkim_exim_init();
2019# ifdef MEASURE_TIMING
2020 report_time_since(&t0, US"dkim_exim_init (delta)");
2021# endif
2022 }
2023#endif
476be7e2
JH
2024
2025#ifdef WITH_CONTENT_SCAN
2026malware_init();
2027#endif
73ec116f
JH
2028#ifdef SUPPORT_SPF
2029spf_init();
2030#endif
059ec3d9
PH
2031
2032/* Close the log so it can be renamed and moved. In the few cases below where
2033this long-running process writes to the log (always exceptional conditions), it
2034closes the log afterwards, for the same reason. */
2035
2036log_close_all();
2037
2038DEBUG(D_any) debug_print_ids(US"daemon running with");
2039
2040/* Any messages accepted via this route are going to be SMTP. */
2041
2042smtp_input = TRUE;
2043
9f01e50d
JH
2044#ifdef MEASURE_TIMING
2045report_time_since(&timestamp_startup, US"daemon loop start"); /* testcase 0022 */
2046#endif
2047
059ec3d9
PH
2048/* Enter the never-ending loop... */
2049
2050for (;;)
2051 {
2052 #if HAVE_IPV6
2053 struct sockaddr_in6 accepted;
2054 #else
2055 struct sockaddr_in accepted;
2056 #endif
2057
cf73943b 2058 EXIM_SOCKLEN_T len;
059ec3d9
PH
2059 pid_t pid;
2060
01446a56
JH
2061 if (sigterm_seen)
2062 daemon_die(); /* Does not return */
2063
059ec3d9 2064 /* This code is placed first in the loop, so that it gets obeyed at the
9ee44efb
PP
2065 start, before the first wait, for the queue-runner case, so that the first
2066 one can be started immediately.
2067
2068 The other option is that we have an inetd wait timeout specified to -bw. */
059ec3d9
PH
2069
2070 if (sigalrm_seen)
2071 {
9ee44efb
PP
2072 if (inetd_wait_timeout > 0)
2073 {
2074 time_t resignal_interval = inetd_wait_timeout;
2075
2076 if (last_connection_time == (time_t)0)
2077 {
2078 DEBUG(D_any)
2079 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
2080 }
2081 else
2082 {
2083 time_t now = time(NULL);
2084 if (now == (time_t)-1)
2085 {
2086 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
2087 }
2088 else
2089 {
2090 if ((now - last_connection_time) >= inetd_wait_timeout)
2091 {
2092 DEBUG(D_any)
2093 debug_printf("inetd wait timeout %d expired, ending daemon\n",
2094 inetd_wait_timeout);
2095 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
2096 version_string);
2097 exit(EXIT_SUCCESS);
2098 }
2099 else
2100 {
2101 resignal_interval -= (now - last_connection_time);
2102 }
2103 }
2104 }
059ec3d9 2105
9ee44efb 2106 sigalrm_seen = FALSE;
c2a1bba0 2107 ALARM(resignal_interval);
9ee44efb 2108 }
059ec3d9 2109
9ee44efb 2110 else
059ec3d9 2111 {
ff966302
JH
2112 DEBUG(D_any) debug_printf("%s received\n",
2113#ifdef EXPERIMENTAL_QUEUE_RAMP
2114 *queuerun_msgid ? "qrun notification" :
2115#endif
2116 "SIGALRM");
8e669ac1 2117
9ee44efb
PP
2118 /* Do a full queue run in a child process, if required, unless we already
2119 have enough queue runners on the go. If we are not running as root, a
2120 re-exec is required. */
059ec3d9 2121
9ee44efb 2122 if (queue_interval > 0 &&
0cd5fd23 2123 (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
9ee44efb
PP
2124 {
2125 if ((pid = fork()) == 0)
2126 {
9ee44efb
PP
2127 DEBUG(D_any) debug_printf("Starting queue-runner: pid %d\n",
2128 (int)getpid());
8e669ac1 2129
9ee44efb
PP
2130 /* Disable debugging if it's required only for the daemon process. We
2131 leave the above message, because it ties up with the "child ended"
2132 debugging messages. */
059ec3d9 2133
8768d548 2134 if (f.debug_daemon) debug_selector = 0;
059ec3d9 2135
9ee44efb 2136 /* Close any open listening sockets in the child */
059ec3d9 2137
8cfc4d82
JH
2138 close_daemon_sockets(daemon_notifier_fd,
2139 listen_sockets, listen_socket_count);
059ec3d9 2140
9ee44efb 2141 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
059ec3d9 2142
9ee44efb
PP
2143 signal(SIGHUP, SIG_DFL);
2144 signal(SIGCHLD, SIG_DFL);
01446a56 2145 signal(SIGTERM, SIG_DFL);
059ec3d9 2146
9ee44efb
PP
2147 /* Re-exec if privilege has been given up, unless deliver_drop_
2148 privilege is set. Reset SIGALRM before exec(). */
4fbcfc2e 2149
9ee44efb 2150 if (geteuid() != root_uid && !deliver_drop_privilege)
4fbcfc2e 2151 {
9ee44efb
PP
2152 uschar opt[8];
2153 uschar *p = opt;
ff966302 2154 uschar *extra[7];
9ee44efb
PP
2155 int extracount = 1;
2156
2157 signal(SIGALRM, SIG_DFL);
2158 *p++ = '-';
2159 *p++ = 'q';
ff966302
JH
2160 if ( f.queue_2stage
2161#ifdef EXPERIMENTAL_QUEUE_RAMP
2162 && !*queuerun_msgid
2163#endif
2164 ) *p++ = 'q';
8768d548
JH
2165 if (f.queue_run_first_delivery) *p++ = 'i';
2166 if (f.queue_run_force) *p++ = 'f';
2167 if (f.deliver_force_thaw) *p++ = 'f';
2168 if (f.queue_run_local) *p++ = 'l';
9ee44efb 2169 *p = 0;
3f008c60 2170 extra[0] = *queue_name
e37f8a84 2171 ? string_sprintf("%sG%s", opt, queue_name) : opt;
9ee44efb 2172
ff966302
JH
2173#ifdef EXPERIMENTAL_QUEUE_RAMP
2174 if (*queuerun_msgid)
2175 {
2176 extra[extracount++] = queuerun_msgid; /* Trigger only the */
2177 extra[extracount++] = queuerun_msgid; /* one message */
2178 }
2179#endif
2180
9ee44efb
PP
2181 /* If -R or -S were on the original command line, ensure they get
2182 passed on. */
2183
e37f8a84 2184 if (deliver_selectstring)
9ee44efb 2185 {
8768d548 2186 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
9ee44efb
PP
2187 extra[extracount++] = deliver_selectstring;
2188 }
2189
e37f8a84 2190 if (deliver_selectstring_sender)
9ee44efb 2191 {
8768d548 2192 extra[extracount++] = f.deliver_selectstring_sender_regex
e37f8a84 2193 ? US"-Sr" : US"-S";
9ee44efb
PP
2194 extra[extracount++] = deliver_selectstring_sender;
2195 }
2196
2197 /* Overlay this process with a new execution. */
2198
ff966302
JH
2199 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
2200 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
9ee44efb
PP
2201
2202 /* Control never returns here. */
4fbcfc2e
PH
2203 }
2204
9ee44efb 2205 /* No need to re-exec; SIGALRM remains set to the default handler */
059ec3d9 2206
ff966302
JH
2207#ifdef EXPERIMENTAL_QUEUE_RAMP
2208 if (*queuerun_msgid)
2209 {
2210 f.queue_2stage = FALSE;
2211 queue_run(queuerun_msgid, queuerun_msgid, FALSE);
2212 }
2213 else
2214#endif
2215 queue_run(NULL, NULL, FALSE);
f3ebb786 2216 exim_underbar_exit(EXIT_SUCCESS);
059ec3d9
PH
2217 }
2218
9ee44efb 2219 if (pid < 0)
059ec3d9 2220 {
9ee44efb
PP
2221 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
2222 "process failed: %s", strerror(errno));
2223 log_close_all();
2224 }
2225 else
2226 {
d7978c0f 2227 for (int i = 0; i < local_queue_run_max; ++i)
9ee44efb
PP
2228 if (queue_pid_slots[i] <= 0)
2229 {
2230 queue_pid_slots[i] = pid;
2231 queue_run_count++;
2232 break;
2233 }
9ee44efb 2234 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
d7978c0f 2235 queue_run_count, queue_run_count == 1 ? "" : "es");
059ec3d9 2236 }
059ec3d9 2237 }
059ec3d9 2238
9ee44efb 2239 /* Reset the alarm clock */
059ec3d9 2240
9ee44efb 2241 sigalrm_seen = FALSE;
ff966302
JH
2242#ifdef EXPERIMENTAL_QUEUE_RAMP
2243 if (*queuerun_msgid)
2244 *queuerun_msgid = 0;
2245 else
2246#endif
2247 ALARM(queue_interval);
9ee44efb
PP
2248 }
2249
2250 } /* sigalrm_seen */
059ec3d9
PH
2251
2252
2253 /* Sleep till a connection happens if listening, and handle the connection if
2254 that is why we woke up. The FreeBSD operating system requires the use of
2255 select() before accept() because the latter function is not interrupted by
2256 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2257 OS do notice signals in accept() but it does no harm to have the select()
2258 in for all of them - and it won't then be a lurking problem for ports to
2259 new OS. In fact, the later addition of listening on specific interfaces only
2260 requires this way of working anyway. */
2261
8768d548 2262 if (f.daemon_listen)
059ec3d9 2263 {
d7978c0f 2264 int lcount, select_errno;
059ec3d9
PH
2265 int max_socket = 0;
2266 BOOL select_failed = FALSE;
2267 fd_set select_listen;
2268
2269 FD_ZERO(&select_listen);
ff966302
JH
2270 if (daemon_notifier_fd >= 0)
2271 FD_SET(daemon_notifier_fd, &select_listen);
d7978c0f 2272 for (int sk = 0; sk < listen_socket_count; sk++)
059ec3d9
PH
2273 {
2274 FD_SET(listen_sockets[sk], &select_listen);
2275 if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk];
2276 }
2277
2278 DEBUG(D_any) debug_printf("Listening...\n");
8e669ac1
PH
2279
2280 /* In rare cases we may have had a SIGCHLD signal in the time between
2281 setting the handler (below) and getting back here. If so, pretend that the
7d468ab8 2282 select() was interrupted so that we reap the child. This might still leave
8e669ac1 2283 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
7d468ab8
PH
2284 only to do the reaping more quickly, it shouldn't result in anything other
2285 than a delay until something else causes a wake-up. */
2286
2287 if (sigchld_seen)
2288 {
2289 lcount = -1;
8e669ac1 2290 errno = EINTR;
7d468ab8
PH
2291 }
2292 else
7d468ab8
PH
2293 lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen,
2294 NULL, NULL, NULL);
059ec3d9 2295
7d468ab8 2296 if (lcount < 0)
059ec3d9
PH
2297 {
2298 select_failed = TRUE;
2299 lcount = 1;
2300 }
8e669ac1
PH
2301
2302 /* Clean up any subprocesses that may have terminated. We need to do this
2303 here so that smtp_accept_max_per_host works when a connection to that host
2304 has completed, and we are about to accept a new one. When this code was
2305 later in the sequence, a new connection could be rejected, even though an
2306 old one had just finished. Preserve the errno from any select() failure for
bb6e88ff 2307 the use of the common select/accept error processing below. */
8e669ac1 2308
bb6e88ff
PH
2309 select_errno = errno;
2310 handle_ending_processes();
8e669ac1
PH
2311 errno = select_errno;
2312
01603eec 2313#ifndef DISABLE_TLS
b10c87b3
JH
2314 /* Create or rotate any required keys */
2315 tls_daemon_init();
2316#endif
2317
059ec3d9 2318 /* Loop for all the sockets that are currently ready to go. If select
7d468ab8
PH
2319 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2320 to use the common error code for select/accept below. */
059ec3d9
PH
2321
2322 while (lcount-- > 0)
2323 {
2324 int accept_socket = -1;
6851a9c5 2325
059ec3d9 2326 if (!select_failed)
ff966302 2327 {
ff966302
JH
2328 if ( daemon_notifier_fd >= 0
2329 && FD_ISSET(daemon_notifier_fd, &select_listen))
2330 {
2331 FD_CLR(daemon_notifier_fd, &select_listen);
2332 sigalrm_seen = daemon_notification();
2333 break; /* to top of daemon loop */
2334 }
d7978c0f 2335 for (int sk = 0; sk < listen_socket_count; sk++)
059ec3d9
PH
2336 if (FD_ISSET(listen_sockets[sk], &select_listen))
2337 {
cf73943b 2338 len = sizeof(accepted);
059ec3d9
PH
2339 accept_socket = accept(listen_sockets[sk],
2340 (struct sockaddr *)&accepted, &len);
2341 FD_CLR(listen_sockets[sk], &select_listen);
2342 break;
2343 }
ff966302 2344 }
059ec3d9
PH
2345
2346 /* If select or accept has failed and this was not caused by an
2347 interruption, log the incident and try again. With asymmetric TCP/IP
2348 routing errors such as "No route to network" have been seen here. Also
2349 "connection reset by peer" has been seen. These cannot be classed as
2350 disastrous errors, but they could fill up a lot of log. The code in smail
2351 crashes the daemon after 10 successive failures of accept, on the grounds
2352 that some OS fail continuously. Exim originally followed suit, but this
2353 appears to have caused problems. Now it just keeps going, but instead of
2354 logging each error, it batches them up when they are continuous. */
2355
2356 if (accept_socket < 0 && errno != EINTR)
2357 {
2358 if (accept_retry_count == 0)
2359 {
2360 accept_retry_errno = errno;
2361 accept_retry_select_failed = select_failed;
2362 }
2363 else
2364 {
2365 if (errno != accept_retry_errno ||
2366 select_failed != accept_retry_select_failed ||
2367 accept_retry_count >= 50)
2368 {
2369 log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0),
2370 "%d %s() failure%s: %s",
2371 accept_retry_count,
2372 accept_retry_select_failed? "select" : "accept",
2373 (accept_retry_count == 1)? "" : "s",
2374 strerror(accept_retry_errno));
2375 log_close_all();
2376 accept_retry_count = 0;
2377 accept_retry_errno = errno;
2378 accept_retry_select_failed = select_failed;
2379 }
2380 }
2381 accept_retry_count++;
2382 }
2383
2384 else
2385 {
2386 if (accept_retry_count > 0)
2387 {
2388 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2389 accept_retry_count,
2390 accept_retry_select_failed? "select" : "accept",
2391 (accept_retry_count == 1)? "" : "s",
2392 strerror(accept_retry_errno));
2393 log_close_all();
2394 accept_retry_count = 0;
2395 }
2396 }
2397
2398 /* If select/accept succeeded, deal with the connection. */
2399
2400 if (accept_socket >= 0)
9ee44efb
PP
2401 {
2402 if (inetd_wait_timeout)
2403 last_connection_time = time(NULL);
059ec3d9
PH
2404 handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,
2405 (struct sockaddr *)&accepted);
9ee44efb 2406 }
059ec3d9
PH
2407 }
2408 }
2409
2410 /* If not listening, then just sleep for the queue interval. If we woke
2411 up early the last time for some other signal, it won't matter because
2412 the alarm signal will wake at the right time. This code originally used
2413 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2414 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2415 select() can be used as an interruptible sleep() on all versions of Unix. */
2416
2417 else
2418 {
2419 struct timeval tv;
2420 tv.tv_sec = queue_interval;
2421 tv.tv_usec = 0;
2422 select(0, NULL, NULL, NULL, &tv);
8e669ac1 2423 handle_ending_processes();
059ec3d9
PH
2424 }
2425
2426 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2427 for itself, because it isn't doing the waiting itself. */
2428
2429 if (sigchld_seen)
2430 {
2431 sigchld_seen = FALSE;
7d468ab8 2432 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
059ec3d9
PH
2433 }
2434
2435 /* Handle being woken by SIGHUP. We know at this point that the result
2436 of accept() has been dealt with, so we can re-exec exim safely, first
2437 closing the listening sockets so that they can be reused. Cancel any pending
2438 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2439 that another HUP in quick succession doesn't clobber the new daemon before it
2440 gets going. All log files get closed by the close-on-exec flag; however, if
2441 the exec fails, we need to close the logs. */
2442
2443 if (sighup_seen)
2444 {
059ec3d9
PH
2445 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2446 getpid());
8cfc4d82
JH
2447 close_daemon_sockets(daemon_notifier_fd,
2448 listen_sockets, listen_socket_count);
c2a1bba0 2449 ALARM_CLR(0);
059ec3d9
PH
2450 signal(SIGHUP, SIG_IGN);
2451 sighup_argv[0] = exim_path;
2452 exim_nullstd();
2453 execv(CS exim_path, (char *const *)sighup_argv);
2454 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2455 getpid(), exim_path, strerror(errno));
2456 log_close_all();
2457 }
2458
2459 } /* End of main loop */
2460
2461/* Control never reaches here */
2462}
2463
071c51f7
JH
2464/* vi: aw ai sw=2
2465*/
059ec3d9 2466/* End of exim_daemon.c */