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[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 */
1e1ddfac 6/* Copyright (c) The Exim Maintainers 2020 */
059ec3d9
PH
7/* See the file NOTICE for conditions of use and distribution. */
8
9/* Functions concerned with running Exim as a daemon */
10
11
12#include "exim.h"
13
14
15/* Structure for holding data for each SMTP connection */
16
17typedef struct smtp_slot {
18 pid_t pid; /* pid of the spawned reception process */
19 uschar *host_address; /* address of the client host */
20} smtp_slot;
21
22/* An empty slot for initializing (Standard C does not allow constructor
4c04137d 23expressions in assignments except as initializers in declarations). */
059ec3d9 24
f2ed27cf 25static smtp_slot empty_smtp_slot = { .pid = 0, .host_address = NULL };
059ec3d9
PH
26
27
28
29/*************************************************
30* Local static variables *
31*************************************************/
32
cd59ab18
PP
33static SIGNAL_BOOL sigchld_seen;
34static SIGNAL_BOOL sighup_seen;
01446a56 35static SIGNAL_BOOL sigterm_seen;
059ec3d9
PH
36
37static int accept_retry_count = 0;
38static int accept_retry_errno;
39static BOOL accept_retry_select_failed;
40
41static int queue_run_count = 0;
bb6e88ff
PH
42static pid_t *queue_pid_slots = NULL;
43static smtp_slot *smtp_slots = NULL;
059ec3d9
PH
44
45static BOOL write_pid = TRUE;
46
47
48
49/*************************************************
50* SIGHUP Handler *
51*************************************************/
52
53/* All this handler does is to set a flag and re-enable the signal.
54
55Argument: the signal number
56Returns: nothing
57*/
58
59static void
60sighup_handler(int sig)
61{
62sig = sig; /* Keep picky compilers happy */
63sighup_seen = TRUE;
64signal(SIGHUP, sighup_handler);
65}
66
67
68
69/*************************************************
70* SIGCHLD handler for main daemon process *
71*************************************************/
72
73/* Don't re-enable the handler here, since we aren't doing the
74waiting here. If the signal is re-enabled, there will just be an
75infinite sequence of calls to this handler. The SIGCHLD signal is
76used just as a means of waking up the daemon so that it notices
77terminated subprocesses as soon as possible.
78
79Argument: the signal number
80Returns: nothing
81*/
82
83static void
84main_sigchld_handler(int sig)
85{
86sig = sig; /* Keep picky compilers happy */
7d468ab8 87os_non_restarting_signal(SIGCHLD, SIG_DFL);
059ec3d9 88sigchld_seen = TRUE;
059ec3d9
PH
89}
90
91
01446a56
JH
92/* SIGTERM handler. Try to get the damon pif file removed
93before exiting. */
94
95static void
96main_sigterm_handler(int sig)
97{
98sigterm_seen = TRUE;
99}
100
101
059ec3d9
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102
103
104/*************************************************
105* Unexpected errors in SMTP calls *
106*************************************************/
107
108/* This function just saves a bit of repetitious coding.
109
110Arguments:
111 log_msg Text of message to be logged
112 smtp_msg Text of SMTP error message
113 was_errno The failing errno
114
115Returns: nothing
116*/
117
118static void
119never_error(uschar *log_msg, uschar *smtp_msg, int was_errno)
120{
52f12a7c
JH
121uschar *emsg = was_errno <= 0
122 ? US"" : string_sprintf(": %s", strerror(was_errno));
059ec3d9 123log_write(0, LOG_MAIN|LOG_PANIC, "%s%s", log_msg, emsg);
52f12a7c 124if (smtp_out) smtp_printf("421 %s\r\n", FALSE, smtp_msg);
059ec3d9
PH
125}
126
127
128
129
130/*************************************************
8cfc4d82
JH
131*************************************************/
132
133static void
134close_daemon_sockets(int daemon_notifier_fd,
135 int * listen_sockets, int listen_socket_count)
136{
137if (daemon_notifier_fd >= 0) (void) close(daemon_notifier_fd);
138for (int i = 0; i < listen_socket_count; i++) (void) close(listen_sockets[i]);
139}
140
141
142/*************************************************
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143* Handle a connected SMTP call *
144*************************************************/
145
146/* This function is called when an SMTP connection has been accepted.
147If there are too many, give an error message and close down. Otherwise
148spin off a sub-process to handle the call. The list of listening sockets
149is required so that they can be closed in the sub-process. Take care not to
150leak store in this process - reset the stacking pool at the end.
151
152Arguments:
153 listen_sockets sockets which are listening for incoming calls
154 listen_socket_count count of listening sockets
155 accept_socket socket of the current accepted call
156 accepted socket information about the current call
157
158Returns: nothing
159*/
160
161static void
162handle_smtp_call(int *listen_sockets, int listen_socket_count,
163 int accept_socket, struct sockaddr *accepted)
164{
165pid_t pid;
166union sockaddr_46 interface_sockaddr;
36a3b041 167EXIM_SOCKLEN_T ifsize = sizeof(interface_sockaddr);
059ec3d9
PH
168int dup_accept_socket = -1;
169int max_for_this_host = 0;
6c6d6e48 170int save_log_selector = *log_selector;
b2bcdd35 171gstring * whofrom;
059ec3d9 172
f3ebb786 173rmark reset_point = store_mark();
059ec3d9
PH
174
175/* Make the address available in ASCII representation, and also fish out
176the remote port. */
177
178sender_host_address = host_ntoa(-1, accepted, NULL, &sender_host_port);
179DEBUG(D_any) debug_printf("Connection request from %s port %d\n",
180 sender_host_address, sender_host_port);
181
182/* Set up the output stream, check the socket has duplicated, and set up the
183input stream. These operations fail only the exceptional circumstances. Note
184that never_error() won't use smtp_out if it is NULL. */
185
f5d25c2b 186if (!(smtp_out = fdopen(accept_socket, "wb")))
059ec3d9
PH
187 {
188 never_error(US"daemon: fdopen() for smtp_out failed", US"", errno);
189 goto ERROR_RETURN;
190 }
191
f5d25c2b 192if ((dup_accept_socket = dup(accept_socket)) < 0)
059ec3d9
PH
193 {
194 never_error(US"daemon: couldn't dup socket descriptor",
195 US"Connection setup failed", errno);
196 goto ERROR_RETURN;
197 }
198
f5d25c2b 199if (!(smtp_in = fdopen(dup_accept_socket, "rb")))
059ec3d9
PH
200 {
201 never_error(US"daemon: fdopen() for smtp_in failed",
202 US"Connection setup failed", errno);
203 goto ERROR_RETURN;
204 }
205
520de300
PH
206/* Get the data for the local interface address. Panic for most errors, but
207"connection reset by peer" just means the connection went away. */
059ec3d9
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208
209if (getsockname(accept_socket, (struct sockaddr *)(&interface_sockaddr),
210 &ifsize) < 0)
211 {
520de300
PH
212 log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC),
213 "getsockname() failed: %s", strerror(errno));
925ac8e4 214 smtp_printf("421 Local problem: getsockname() failed; please try again later\r\n", FALSE);
059ec3d9
PH
215 goto ERROR_RETURN;
216 }
217
218interface_address = host_ntoa(-1, &interface_sockaddr, NULL, &interface_port);
219DEBUG(D_interface) debug_printf("interface address=%s port=%d\n",
220 interface_address, interface_port);
221
222/* Build a string identifying the remote host and, if requested, the port and
223the local interface data. This is for logging; at the end of this function the
224memory is reclaimed. */
225
b2bcdd35 226whofrom = string_append(NULL, 3, "[", sender_host_address, "]");
059ec3d9 227
6c6d6e48 228if (LOGGING(incoming_port))
52f12a7c 229 whofrom = string_fmt_append(whofrom, ":%d", sender_host_port);
059ec3d9 230
6c6d6e48 231if (LOGGING(incoming_interface))
52f12a7c
JH
232 whofrom = string_fmt_append(whofrom, " I=[%s]:%d",
233 interface_address, interface_port);
059ec3d9 234
acec9514 235(void) string_from_gstring(whofrom); /* Terminate the newly-built string */
059ec3d9
PH
236
237/* Check maximum number of connections. We do not check for reserved
238connections or unacceptable hosts here. That is done in the subprocess because
239it might take some time. */
240
241if (smtp_accept_max > 0 && smtp_accept_count >= smtp_accept_max)
242 {
243 DEBUG(D_any) debug_printf("rejecting SMTP connection: count=%d max=%d\n",
244 smtp_accept_count, smtp_accept_max);
245 smtp_printf("421 Too many concurrent SMTP connections; "
925ac8e4 246 "please try again later.\r\n", FALSE);
059ec3d9
PH
247 log_write(L_connection_reject,
248 LOG_MAIN, "Connection from %s refused: too many connections",
acec9514 249 whofrom->s);
059ec3d9
PH
250 goto ERROR_RETURN;
251 }
252
253/* If a load limit above which only reserved hosts are acceptable is defined,
254get the load average here, and if there are in fact no reserved hosts, do
255the test right away (saves a fork). If there are hosts, do the check in the
256subprocess because it might take time. */
257
258if (smtp_load_reserve >= 0)
259 {
8669f003 260 load_average = OS_GETLOADAVG();
059ec3d9
PH
261 if (smtp_reserve_hosts == NULL && load_average > smtp_load_reserve)
262 {
263 DEBUG(D_any) debug_printf("rejecting SMTP connection: load average = %.2f\n",
264 (double)load_average/1000.0);
925ac8e4 265 smtp_printf("421 Too much load; please try again later.\r\n", FALSE);
059ec3d9
PH
266 log_write(L_connection_reject,
267 LOG_MAIN, "Connection from %s refused: load average = %.2f",
acec9514 268 whofrom->s, (double)load_average/1000.0);
059ec3d9
PH
269 goto ERROR_RETURN;
270 }
271 }
272
273/* Check that one specific host (strictly, IP address) is not hogging
274resources. This is done here to prevent a denial of service attack by someone
275forcing you to fork lots of times before denying service. The value of
276smtp_accept_max_per_host is a string which is expanded. This makes it possible
277to provide host-specific limits according to $sender_host address, but because
278this is in the daemon mainline, only fast expansions (such as inline address
279checks) should be used. The documentation is full of warnings. */
280
281if (smtp_accept_max_per_host != NULL)
282 {
283 uschar *expanded = expand_string(smtp_accept_max_per_host);
284 if (expanded == NULL)
285 {
8768d548 286 if (!f.expand_string_forcedfail)
059ec3d9 287 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
acec9514 288 "failed for %s: %s", whofrom->s, expand_string_message);
059ec3d9
PH
289 }
290 /* For speed, interpret a decimal number inline here */
291 else
292 {
293 uschar *s = expanded;
294 while (isdigit(*s))
295 max_for_this_host = max_for_this_host * 10 + *s++ - '0';
296 if (*s != 0)
297 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
acec9514 298 "for %s contains non-digit: %s", whofrom->s, expanded);
059ec3d9
PH
299 }
300 }
301
302/* If we have fewer connections than max_for_this_host, we can skip the tedious
303per host_address checks. Note that at this stage smtp_accept_count contains the
304count of *other* connections, not including this one. */
305
306if ((max_for_this_host > 0) &&
307 (smtp_accept_count >= max_for_this_host))
308 {
059ec3d9
PH
309 int host_accept_count = 0;
310 int other_host_count = 0; /* keep a count of non matches to optimise */
311
d7978c0f 312 for (int i = 0; i < smtp_accept_max; ++i)
8cfd0f7b 313 if (smtp_slots[i].host_address)
059ec3d9
PH
314 {
315 if (Ustrcmp(sender_host_address, smtp_slots[i].host_address) == 0)
316 host_accept_count++;
317 else
318 other_host_count++;
319
320 /* Testing all these strings is expensive - see if we can drop out
321 early, either by hitting the target, or finding there are not enough
322 connections left to make the target. */
323
324 if ((host_accept_count >= max_for_this_host) ||
325 ((smtp_accept_count - other_host_count) < max_for_this_host))
326 break;
327 }
059ec3d9
PH
328
329 if (host_accept_count >= max_for_this_host)
330 {
331 DEBUG(D_any) debug_printf("rejecting SMTP connection: too many from this "
332 "IP address: count=%d max=%d\n",
333 host_accept_count, max_for_this_host);
334 smtp_printf("421 Too many concurrent SMTP connections "
925ac8e4 335 "from this IP address; please try again later.\r\n", FALSE);
059ec3d9
PH
336 log_write(L_connection_reject,
337 LOG_MAIN, "Connection from %s refused: too many connections "
acec9514 338 "from that IP address", whofrom->s);
059ec3d9
PH
339 goto ERROR_RETURN;
340 }
341 }
342
343/* OK, the connection count checks have been passed. Before we can fork the
344accepting process, we must first log the connection if requested. This logging
345used to happen in the subprocess, but doing that means that the value of
346smtp_accept_count can be out of step by the time it is logged. So we have to do
347the logging here and accept the performance cost. Note that smtp_accept_count
348hasn't yet been incremented to take account of this connection.
349
350In order to minimize the cost (because this is going to happen for every
351connection), do a preliminary selector test here. This saves ploughing through
352the generalized logging code each time when the selector is false. If the
353selector is set, check whether the host is on the list for logging. If not,
354arrange to unset the selector in the subprocess. */
355
6c6d6e48 356if (LOGGING(smtp_connection))
059ec3d9
PH
357 {
358 uschar *list = hosts_connection_nolog;
ce325893 359 memset(sender_host_cache, 0, sizeof(sender_host_cache));
059ec3d9 360 if (list != NULL && verify_check_host(&list) == OK)
6c6d6e48 361 save_log_selector &= ~L_smtp_connection;
059ec3d9
PH
362 else
363 log_write(L_smtp_connection, LOG_MAIN, "SMTP connection from %s "
acec9514 364 "(TCP/IP connection count = %d)", whofrom->s, smtp_accept_count + 1);
059ec3d9
PH
365 }
366
367/* Now we can fork the accepting process; do a lookup tidy, just in case any
368expansion above did a lookup. */
369
370search_tidyup();
81022793 371pid = exim_fork(US"daemon-accept");
059ec3d9
PH
372
373/* Handle the child process */
374
375if (pid == 0)
376 {
059ec3d9
PH
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();
81022793 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();
81022793 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 */
81022793 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");
81022793 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
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();
81022793 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));
81022793 957exim_exit(EXIT_SUCCESS);
01446a56
JH
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 }
81022793 997exim_exit(EXIT_SUCCESS);
01446a56
JH
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;
ff966302
JH
1088
1089buf[sizeof(buf)-1] = 0;
1090if ((sz = recvmsg(daemon_notifier_fd, &msg, 0)) <= 0) return FALSE;
1091if (sz >= sizeof(buf)) return FALSE;
1092
04403ab0
JH
1093#ifdef notdef
1094debug_printf("addrlen %d\n", msg.msg_namelen);
1095#endif
2f2dd3a5 1096DEBUG(D_queue_run) debug_printf("%s from addr '%s%.*s'\n", __FUNCTION__,
3978c243
JH
1097 *sa_un.sun_path ? "" : "@",
1098 (int)msg.msg_namelen - (*sa_un.sun_path ? 0 : 1),
1099 sa_un.sun_path + (*sa_un.sun_path ? 0 : 1));
04403ab0
JH
1100
1101/* Refuse to handle the item unless the peer has good credentials */
f254e592
JH
1102#ifdef SCM_CREDENTIALS
1103# define EXIM_SCM_CR_TYPE SCM_CREDENTIALS
5399df80 1104#elif defined(LOCAL_CREDS) && defined(SCM_CREDS)
f254e592
JH
1105# define EXIM_SCM_CR_TYPE SCM_CREDS
1106#else
2f2dd3a5
JH
1107 /* The OS has no way to get the creds of the caller (for a unix/datagram socket.
1108 Punt; don't try to check. */
f254e592 1109#endif
04403ab0 1110
2f2dd3a5 1111#ifdef EXIM_SCM_CR_TYPE
ff966302
JH
1112for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg);
1113 cp;
1114 cp = CMSG_NXTHDR(&msg, cp))
f254e592 1115 if (cp->cmsg_level == SOL_SOCKET && cp->cmsg_type == EXIM_SCM_CR_TYPE)
ff966302 1116 {
2f2dd3a5 1117# ifdef SCM_CREDENTIALS /* Linux */
ff966302
JH
1118 struct ucred * cr = (struct ucred *) CMSG_DATA(cp);
1119 if (cr->uid && cr->uid != exim_uid)
1120 {
1121 DEBUG(D_queue_run) debug_printf("%s: sender creds pid %d uid %d gid %d\n",
1122 __FUNCTION__, (int)cr->pid, (int)cr->uid, (int)cr->gid);
1123 return FALSE;
2f2dd3a5
JH
1124 }
1125# elif defined(LOCAL_CREDS) /* BSD-ish */
5399df80
JH
1126 struct sockcred * cr = (struct sockcred *) CMSG_DATA(cp);
1127 if (cr->sc_uid && cr->sc_uid != exim_uid)
f254e592 1128 {
5399df80
JH
1129 DEBUG(D_queue_run) debug_printf("%s: sender creds pid ??? uid %d gid %d\n",
1130 __FUNCTION__, (int)cr->sc_uid, (int)cr->sc_gid);
f254e592 1131 return FALSE;
ff966302 1132 }
2f2dd3a5 1133# endif
ff966302
JH
1134 break;
1135 }
2f2dd3a5 1136#endif
ff966302
JH
1137
1138buf[sz] = 0;
1139switch (buf[0])
1140 {
4c2efd7a 1141#ifdef EXPERIMENTAL_QUEUE_RAMP
ff966302
JH
1142 case NOTIFY_MSG_QRUN:
1143 /* this should be a message_id */
1144 DEBUG(D_queue_run)
1145 debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1);
1146 memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1);
1147 return TRUE;
4c2efd7a 1148#endif /*EXPERIMENTAL_QUEUE_RAMP*/
04403ab0
JH
1149
1150 case NOTIFY_QUEUE_SIZE_REQ:
1151 {
1152 uschar buf[16];
1153 int len = snprintf(CS buf, sizeof(buf), "%u", queue_count_cached());
1154
1155 DEBUG(D_queue_run)
1156 debug_printf("%s: queue size request: %s\n", __FUNCTION__, buf);
1157
f254e592 1158 if (sendto(daemon_notifier_fd, buf, len, 0,
3978c243 1159 (const struct sockaddr *)&sa_un, msg.msg_namelen) < 0)
04403ab0
JH
1160 log_write(0, LOG_MAIN|LOG_PANIC,
1161 "%s: sendto: %s\n", __FUNCTION__, strerror(errno));
1162 return FALSE;
1163 }
ff966302
JH
1164 }
1165return FALSE;
1166}
ff966302
JH
1167
1168
059ec3d9
PH
1169/*************************************************
1170* Exim Daemon Mainline *
1171*************************************************/
1172
1173/* The daemon can do two jobs, either of which is optional:
1174
1175(1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1176each one. This is requested by the -bd option, with -oX specifying the SMTP
1177port on which to listen (for testing).
1178
1179(2) Spawns a queue-running process every so often. This is controlled by the
1180-q option with a an interval time. (If no time is given, a single queue run
1181is done from the main function, and control doesn't get here.)
1182
1183Root privilege is required in order to attach to port 25. Some systems require
1184it when calling socket() rather than bind(). To cope with all cases, we run as
1185root for both socket() and bind(). Some systems also require root in order to
1186write to the pid file directory. This function must therefore be called as root
1187if it is to work properly in all circumstances. Once the socket is bound and
1188the pid file written, root privilege is given up if there is an exim uid.
1189
1190There are no arguments to this function, and it never returns. */
1191
1192void
1193daemon_go(void)
1194{
ebeaf996 1195struct passwd *pw;
059ec3d9
PH
1196int *listen_sockets = NULL;
1197int listen_socket_count = 0;
1198ip_address_item *addresses = NULL;
9ee44efb 1199time_t last_connection_time = (time_t)0;
4dc2379a 1200int local_queue_run_max = atoi(CS expand_string(queue_run_max));
059ec3d9 1201
81022793
JH
1202process_purpose = US"daemon";
1203
059ec3d9
PH
1204/* If any debugging options are set, turn on the D_pid bit so that all
1205debugging lines get the pid added. */
1206
1207DEBUG(D_any|D_v) debug_selector |= D_pid;
1208
8768d548 1209if (f.inetd_wait_mode)
9ee44efb 1210 {
9ee44efb 1211 listen_socket_count = 1;
f3ebb786 1212 listen_sockets = store_get(sizeof(int), FALSE);
9ee44efb
PP
1213 (void) close(3);
1214 if (dup2(0, 3) == -1)
9ee44efb
PP
1215 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1216 "failed to dup inetd socket safely away: %s", strerror(errno));
d4ff61d1 1217
9ee44efb
PP
1218 listen_sockets[0] = 3;
1219 (void) close(0);
1220 (void) close(1);
1221 (void) close(2);
1222 exim_nullstd();
1223
1224 if (debug_file == stderr)
1225 {
1226 /* need a call to log_write before call to open debug_file, so that
1227 log.c:file_path has been initialised. This is unfortunate. */
1228 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1229
1230 fclose(debug_file);
1231 debug_file = NULL;
1232 exim_nullstd(); /* re-open fd2 after we just closed it again */
1233 debug_logging_activate(US"-wait", NULL);
1234 }
1235
1236 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1237
1238 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1239 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1240
d4ff61d1
JH
1241 if (tcp_nodelay)
1242 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1243 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1244 strerror(errno));
9ee44efb
PP
1245 }
1246
1247
8768d548 1248if (f.inetd_wait_mode || f.daemon_listen)
9ee44efb
PP
1249 {
1250 /* If any option requiring a load average to be available during the
1251 reception of a message is set, call os_getloadavg() while we are root
1252 for those OS for which this is necessary the first time it is called (in
1253 order to perform an "open" on the kernel memory file). */
1254
1255 #ifdef LOAD_AVG_NEEDS_ROOT
1256 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1257 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1258 (void)os_getloadavg();
1259 #endif
1260 }
1261
059ec3d9
PH
1262
1263/* Do the preparation for setting up a listener on one or more interfaces, and
1264possible on various ports. This is controlled by the combination of
1265local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1266(which is a list of default ports to use for those items in local_interfaces
1267that do not specify a port). The -oX command line option can be used to
1268override one or both of these options.
1269
1270If local_interfaces is not set, the default is to listen on all interfaces.
1271When it is set, it can include "all IPvx interfaces" as an item. This is useful
1272when different ports are in use.
1273
1274It turns out that listening on all interfaces is messy in an IPv6 world,
1275because several different implementation approaches have been taken. This code
1276is now supposed to work with all of them. The point of difference is whether an
1277IPv6 socket that is listening on all interfaces will receive incoming IPv4
1278calls or not. We also have to cope with the case when IPv6 libraries exist, but
1279there is no IPv6 support in the kernel.
1280
1281. On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1282 addresses. However, if an IPv4 socket is also listening on all interfaces,
1283 calls are directed to the appropriate socket.
1284
1285. On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1286 give them as mapped addresses, but an attempt also to listen on an IPv4
1287 socket on all interfaces causes an error.
1288
1289. On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1290 two sockets if you want to accept both kinds of call.
1291
1292. FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1293 can be turned off, to make it behave like the versions of Linux described
1294 above.
1295
1296. I heard a report that the USAGI IPv6 stack for Linux has implemented
1297 IPV6_V6ONLY.
1298
1299So, what we do when IPv6 is supported is as follows:
1300
1301 (1) After it is set up, the list of interfaces is scanned for wildcard
1302 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1303 port, the list is re-arranged so that they are together, with the IPv6
1304 wildcard first.
1305
1306 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1307 carry on if an IPv4 wildcard socket for the same port follows later in the
1308 list. This allows Exim to carry on in the case when the kernel has no IPv6
1309 support.
1310
1311 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1312 option is defined. However, if setting fails, carry on regardless (but log
1313 the incident).
1314
1315 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1316 error.
1317
1318 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1319 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1320 port (which must have succeeded or we wouldn't have got this far), we
1321 assume we are in the situation where just a single socket is permitted,
1322 and ignore the error.
1323
1324Phew!
1325
1326The preparation code decodes options and sets up the relevant data. We do this
1327first, so that we can return non-zero if there are any syntax errors, and also
1328write to stderr. */
1329
8768d548 1330if (f.daemon_listen && !f.inetd_wait_mode)
059ec3d9
PH
1331 {
1332 int *default_smtp_port;
1333 int sep;
1334 int pct = 0;
1335 uschar *s;
55414b25 1336 const uschar * list;
059ec3d9
PH
1337 uschar *local_iface_source = US"local_interfaces";
1338 ip_address_item *ipa;
1339 ip_address_item **pipa;
1340
059ec3d9
PH
1341 /* If -oX was used, disable the writing of a pid file unless -oP was
1342 explicitly used to force it. Then scan the string given to -oX. Any items
1343 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1344 Any other items are used to override local_interfaces. */
1345
acec9514 1346 if (override_local_interfaces)
059ec3d9 1347 {
acec9514
JH
1348 gstring * new_smtp_port = NULL;
1349 gstring * new_local_interfaces = NULL;
059ec3d9 1350
01446a56 1351 if (!override_pid_file_path) write_pid = FALSE;
059ec3d9
PH
1352
1353 list = override_local_interfaces;
1354 sep = 0;
ba74fb8d 1355 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
059ec3d9
PH
1356 {
1357 uschar joinstr[4];
01446a56 1358 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
059ec3d9 1359
acec9514 1360 if (!*gp)
059ec3d9
PH
1361 {
1362 joinstr[0] = sep;
1363 joinstr[1] = ' ';
acec9514 1364 *gp = string_catn(*gp, US"<", 1);
059ec3d9
PH
1365 }
1366
acec9514
JH
1367 *gp = string_catn(*gp, joinstr, 2);
1368 *gp = string_cat (*gp, s);
059ec3d9
PH
1369 }
1370
acec9514 1371 if (new_smtp_port)
059ec3d9 1372 {
acec9514 1373 daemon_smtp_port = string_from_gstring(new_smtp_port);
059ec3d9
PH
1374 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1375 daemon_smtp_port);
1376 }
1377
acec9514 1378 if (new_local_interfaces)
059ec3d9 1379 {
acec9514 1380 local_interfaces = string_from_gstring(new_local_interfaces);
059ec3d9
PH
1381 local_iface_source = US"-oX data";
1382 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1383 local_interfaces);
1384 }
1385 }
1386
1387 /* Create a list of default SMTP ports, to be used if local_interfaces
4c04137d 1388 contains entries without explicit ports. First count the number of ports, then
059ec3d9
PH
1389 build a translated list in a vector. */
1390
1391 list = daemon_smtp_port;
1392 sep = 0;
ba74fb8d 1393 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
059ec3d9 1394 pct++;
f3ebb786 1395 default_smtp_port = store_get((pct+1) * sizeof(int), FALSE);
059ec3d9
PH
1396 list = daemon_smtp_port;
1397 sep = 0;
1398 for (pct = 0;
ba74fb8d 1399 (s = string_nextinlist(&list, &sep, NULL, 0));
059ec3d9
PH
1400 pct++)
1401 {
1402 if (isdigit(*s))
1403 {
1404 uschar *end;
1405 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1406 if (end != s + Ustrlen(s))
1407 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1408 }
1409 else
1410 {
1411 struct servent *smtp_service = getservbyname(CS s, "tcp");
071c51f7 1412 if (!smtp_service)
059ec3d9
PH
1413 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1414 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1415 }
1416 }
1417 default_smtp_port[pct] = 0;
1418
071c51f7
JH
1419 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1420
1421 list = tls_in.on_connect_ports;
1422 sep = 0;
1423 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1424 if (!isdigit(*s))
1425 {
acec9514 1426 gstring * g = NULL;
4226691b 1427
071c51f7
JH
1428 list = tls_in.on_connect_ports;
1429 tls_in.on_connect_ports = NULL;
1430 sep = 0;
1431 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1432 {
1433 if (!isdigit(*s))
1434 {
4226691b 1435 struct servent * smtp_service = getservbyname(CS s, "tcp");
071c51f7
JH
1436 if (!smtp_service)
1437 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
4226691b 1438 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
071c51f7 1439 }
acec9514 1440 g = string_append_listele(g, ':', s);
071c51f7 1441 }
acec9514
JH
1442 if (g)
1443 tls_in.on_connect_ports = g->s;
071c51f7
JH
1444 break;
1445 }
1446
059ec3d9
PH
1447 /* Create the list of local interfaces, possibly with ports included. This
1448 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1449 values are converted below. */
1450
1451 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1452
1453 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1454 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1455 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1456 anyway, but we need to know which are the wildcard addresses, and the shorter
1457 strings are neater.
1458
1459 In the same scan, fill in missing port numbers from the default list. When
1460 there is more than one item in the list, extra items are created. */
1461
b891534f 1462 for (ipa = addresses; ipa; ipa = ipa->next)
059ec3d9 1463 {
b891534f
JH
1464 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1465 ipa->address[0] = 0;
059ec3d9
PH
1466 else if (Ustrcmp(ipa->address, "::0") == 0)
1467 {
1468 ipa->address[0] = ':';
1469 ipa->address[1] = 0;
1470 }
1471
1472 if (ipa->port > 0) continue;
1473
1474 if (daemon_smtp_port[0] <= 0)
1475 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1476 "%s and daemon_smtp_port is unset; cannot start daemon",
b891534f
JH
1477 ipa->address[0] == 0 ? US"\"all IPv4\"" :
1478 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
1479
059ec3d9 1480 ipa->port = default_smtp_port[0];
d7978c0f 1481 for (int i = 1; default_smtp_port[i] > 0; i++)
059ec3d9 1482 {
f3ebb786 1483 ip_address_item *new = store_get(sizeof(ip_address_item), FALSE);
b891534f 1484
059ec3d9
PH
1485 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1486 new->port = default_smtp_port[i];
1487 new->next = ipa->next;
1488 ipa->next = new;
1489 ipa = new;
1490 }
1491 }
1492
1493 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1494 wildcard for the same port, ensure that (a) they are together and (b) the
1495 IPv6 address comes first. This makes handling the messy features easier, and
1496 also simplifies the construction of the "daemon started" log line. */
1497
1498 pipa = &addresses;
b891534f 1499 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
059ec3d9
PH
1500 {
1501 ip_address_item *ipa2;
1502
1503 /* Handle an IPv4 wildcard */
1504
1505 if (ipa->address[0] == 0)
b891534f 1506 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
059ec3d9
PH
1507 {
1508 ip_address_item *ipa3 = ipa2->next;
1509 if (ipa3->address[0] == ':' &&
1510 ipa3->address[1] == 0 &&
1511 ipa3->port == ipa->port)
1512 {
1513 ipa2->next = ipa3->next;
1514 ipa3->next = ipa;
1515 *pipa = ipa3;
1516 break;
1517 }
1518 }
059ec3d9
PH
1519
1520 /* Handle an IPv6 wildcard. */
1521
1522 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
b891534f 1523 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
059ec3d9
PH
1524 {
1525 ip_address_item *ipa3 = ipa2->next;
1526 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1527 {
1528 ipa2->next = ipa3->next;
1529 ipa3->next = ipa->next;
1530 ipa->next = ipa3;
1531 ipa = ipa3;
1532 break;
1533 }
1534 }
059ec3d9
PH
1535 }
1536
1537 /* Get a vector to remember all the sockets in */
1538
b891534f 1539 for (ipa = addresses; ipa; ipa = ipa->next)
059ec3d9 1540 listen_socket_count++;
f3ebb786 1541 listen_sockets = store_get(sizeof(int) * listen_socket_count, FALSE);
059ec3d9 1542
9ee44efb
PP
1543 } /* daemon_listen but not inetd_wait_mode */
1544
8768d548 1545if (f.daemon_listen)
9ee44efb
PP
1546 {
1547
059ec3d9
PH
1548 /* Do a sanity check on the max connects value just to save us from getting
1549 a huge amount of store. */
1550
1551 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1552
1553 /* There's no point setting smtp_accept_queue unless it is less than the max
1554 connects limit. The configuration reader ensures that the max is set if the
1555 queue-only option is set. */
1556
1557 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1558
1559 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1560 track of them for total number and queue/host limits. */
1561
1562 if (smtp_accept_max > 0)
1563 {
f3ebb786 1564 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), FALSE);
d7978c0f 1565 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
059ec3d9
PH
1566 }
1567 }
1568
76a2d7ba
PH
1569/* The variable background_daemon is always false when debugging, but
1570can also be forced false in order to keep a non-debugging daemon in the
1571foreground. If background_daemon is true, close all open file descriptors that
9ee44efb
PP
1572we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1573do this for inetd_wait mode.
76a2d7ba
PH
1574
1575This is protection against any called functions (in libraries, or in
1576Perl, or whatever) that think they can write to stderr (or stdout). Before this
1577was added, it was quite likely that an SMTP connection would use one of these
1578file descriptors, in which case writing random stuff to it caused chaos.
1579
1580Then disconnect from the controlling terminal, Most modern Unixes seem to have
1581setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1582setsid() can be #defined as a no-op, or as something else. */
059ec3d9 1583
8768d548 1584if (f.background_daemon || f.inetd_wait_mode)
059ec3d9 1585 {
76a2d7ba
PH
1586 log_close_all(); /* Just in case anything was logged earlier */
1587 search_tidyup(); /* Just in case any were used in reading the config. */
f1e894f3
PH
1588 (void)close(0); /* Get rid of stdin/stdout/stderr */
1589 (void)close(1);
1590 (void)close(2);
8e669ac1 1591 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
059ec3d9 1592 log_stderr = NULL; /* So no attempt to copy paniclog output */
9ee44efb 1593 }
059ec3d9 1594
8768d548 1595if (f.background_daemon)
9ee44efb 1596 {
059ec3d9 1597 /* If the parent process of this one has pid == 1, we are re-initializing the
8e669ac1 1598 daemon as the result of a SIGHUP. In this case, there is no need to do
76a2d7ba
PH
1599 anything, because the controlling terminal has long gone. Otherwise, fork, in
1600 case current process is a process group leader (see 'man setsid' for an
1601 explanation) before calling setsid(). */
059ec3d9
PH
1602
1603 if (getppid() != 1)
1604 {
8e9fdd63 1605 pid_t pid = exim_fork(US"daemon");
059ec3d9
PH
1606 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1607 "fork() failed when starting daemon: %s", strerror(errno));
1608 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1609 (void)setsid(); /* release controlling terminal */
1610 }
1611 }
1612
1613/* We are now in the disconnected, daemon process (unless debugging). Set up
1614the listening sockets if required. */
1615
4c2efd7a 1616daemon_notifier_socket();
ff966302 1617
8768d548 1618if (f.daemon_listen && !f.inetd_wait_mode)
059ec3d9
PH
1619 {
1620 int sk;
059ec3d9
PH
1621 ip_address_item *ipa;
1622
1623 /* For each IP address, create a socket, bind it to the appropriate port, and
1624 start listening. See comments above about IPv6 sockets that may or may not
1625 accept IPv4 calls when listening on all interfaces. We also have to cope with
1626 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1627 listening, provided a wildcard IPv4 socket for the same port follows. */
1628
1629 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1630 {
1631 BOOL wildcard;
1632 ip_address_item *ipa2;
059ec3d9
PH
1633 int af;
1634
1635 if (Ustrchr(ipa->address, ':') != NULL)
1636 {
1637 af = AF_INET6;
1638 wildcard = ipa->address[1] == 0;
1639 }
1640 else
1641 {
1642 af = AF_INET;
1643 wildcard = ipa->address[0] == 0;
1644 }
1645
96f5fe4c 1646 if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0)
059ec3d9
PH
1647 {
1648 if (check_special_case(0, addresses, ipa, FALSE))
1649 {
1650 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1651 "listening (%s): will use IPv4", strerror(errno));
1652 goto SKIP_SOCKET;
1653 }
1654 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1655 (af == AF_INET6)? '6' : '4', strerror(errno));
1656 }
1657
1658 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1659 available. Just log failure (can get protocol not available, just like
1660 socket creation can). */
1661
b891534f 1662#ifdef IPV6_V6ONLY
059ec3d9 1663 if (af == AF_INET6 && wildcard &&
5903c6ff 1664 setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, CS (&on),
059ec3d9
PH
1665 sizeof(on)) < 0)
1666 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1667 "socket failed (%s): carrying on without it", strerror(errno));
b891534f 1668#endif /* IPV6_V6ONLY */
059ec3d9
PH
1669
1670 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1671 is being handled. Without this, a connection will prevent reuse of the
1672 smtp port for listening. */
1673
1674 if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR,
5903c6ff 1675 US (&on), sizeof(on)) < 0)
059ec3d9
PH
1676 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1677 "failed when starting daemon: %s", strerror(errno));
1678
1679 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1680 disable this because it breaks some broken clients. */
1681
1682 if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY,
5903c6ff 1683 US (&on), sizeof(on));
059ec3d9
PH
1684
1685 /* Now bind the socket to the required port; if Exim is being restarted
1686 it may not always be possible to bind immediately, even with SO_REUSEADDR
1687 set, so try 10 times, waiting between each try. After 10 failures, we give
1688 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1689 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1690 address for the same port, ignore the error on the grounds that we must be
1691 in a system where the IPv6 socket accepts both kinds of call. This is
1692 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1693 listen() stage instead. */
1694
6af7e591 1695#ifdef TCP_FASTOPEN
8768d548 1696 f.tcp_fastopen_ok = TRUE;
6af7e591 1697#endif
059ec3d9
PH
1698 for(;;)
1699 {
1700 uschar *msg, *addr;
1701 if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break;
1702 if (check_special_case(errno, addresses, ipa, TRUE))
1703 {
1704 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1705 "listen() success; EADDRINUSE ignored\n");
f1e894f3 1706 (void)close(listen_sockets[sk]);
059ec3d9
PH
1707 goto SKIP_SOCKET;
1708 }
1709 msg = US strerror(errno);
b891534f
JH
1710 addr = wildcard
1711 ? af == AF_INET6
1712 ? US"(any IPv6)"
1713 : US"(any IPv4)"
1714 : ipa->address;
4aee0225 1715 if (daemon_startup_retries <= 0)
059ec3d9
PH
1716 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1717 "socket bind() to port %d for address %s failed: %s: "
1718 "daemon abandoned", ipa->port, addr, msg);
1719 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
4aee0225
PH
1720 "failed: %s: waiting %s before trying again (%d more %s)",
1721 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1722 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1723 daemon_startup_retries--;
1724 sleep(daemon_startup_sleep);
059ec3d9
PH
1725 }
1726
1727 DEBUG(D_any)
059ec3d9
PH
1728 if (wildcard)
1729 debug_printf("listening on all interfaces (IPv%c) port %d\n",
fb05276a 1730 af == AF_INET6 ? '6' : '4', ipa->port);
059ec3d9
PH
1731 else
1732 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
fb05276a 1733
b536a578 1734#if defined(TCP_FASTOPEN) && !defined(__APPLE__)
590faf89
JH
1735 if ( f.tcp_fastopen_ok
1736 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
4670e9d3 1737 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
6af7e591 1738 {
a23ff3b4 1739 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
8768d548 1740 f.tcp_fastopen_ok = FALSE;
6af7e591 1741 }
fb05276a 1742#endif
059ec3d9
PH
1743
1744 /* Start listening on the bound socket, establishing the maximum backlog of
1745 connections that is allowed. On success, continue to the next address. */
1746
b536a578
JH
1747 if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0)
1748 {
1749#if defined(TCP_FASTOPEN) && defined(__APPLE__)
1750 if ( f.tcp_fastopen_ok
1751 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1752 &on, sizeof(on)))
1753 {
1754 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1755 f.tcp_fastopen_ok = FALSE;
1756 }
1757#endif
1758 continue;
1759 }
059ec3d9
PH
1760
1761 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1762 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1763 and there was a previous successful IPv6 wildcard listen on the same port,
1764 we want to ignore the error on the grounds that we must be in a system
1765 where the IPv6 socket accepts both kinds of call. */
1766
1767 if (!check_special_case(errno, addresses, ipa, TRUE))
1768 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
fb05276a
JH
1769 wildcard
1770 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
059ec3d9
PH
1771 strerror(errno));
1772
1773 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1774 "listen() success; EADDRINUSE ignored\n");
f1e894f3 1775 (void)close(listen_sockets[sk]);
059ec3d9
PH
1776
1777 /* Come here if there has been a problem with the socket which we
1778 are going to ignore. We remove the address from the chain, and back up the
1779 counts. */
1780
b891534f 1781 SKIP_SOCKET:
059ec3d9
PH
1782 sk--; /* Back up the count */
1783 listen_socket_count--; /* Reduce the total */
1784 if (ipa == addresses) addresses = ipa->next; else
1785 {
1786 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1787 ipa2->next = ipa->next;
1788 ipa = ipa2;
1789 }
1790 } /* End of bind/listen loop for each address */
1791 } /* End of setup for listening */
1792
1793
1794/* If we are not listening, we want to write a pid file only if -oP was
1795explicitly given. */
1796
b891534f
JH
1797else if (!override_pid_file_path)
1798 write_pid = FALSE;
059ec3d9
PH
1799
1800/* Write the pid to a known file for assistance in identification, if required.
1801We do this before giving up root privilege, because on some systems it is
1802necessary to be root in order to write into the pid file directory. There's
1803nothing to stop multiple daemons running, as long as no more than one listens
1804on a given TCP/IP port on the same interface(s). However, in these
1805circumstances it gets far too complicated to mess with pid file names
1806automatically. Consequently, Exim 4 writes a pid file only
1807
1808 (a) When running in the test harness, or
1809 (b) When -bd is used and -oX is not used, or
1810 (c) When -oP is used to supply a path.
1811
1812The variable daemon_write_pid is used to control this. */
1813
8768d548 1814if (f.running_in_test_harness || write_pid)
059ec3d9
PH
1815 {
1816 FILE *f;
1817
01446a56 1818 set_pid_file_path();
b891534f 1819 if ((f = modefopen(pid_file_path, "wb", 0644)))
059ec3d9 1820 {
ff790e47 1821 (void)fprintf(f, "%d\n", (int)getpid());
ff790e47 1822 (void)fclose(f);
059ec3d9
PH
1823 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1824 }
1825 else
059ec3d9
PH
1826 DEBUG(D_any)
1827 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
1828 pid_file_path));
059ec3d9
PH
1829 }
1830
1831/* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1832
1833sighup_seen = FALSE;
1834signal(SIGHUP, sighup_handler);
1835
1836/* Give up root privilege at this point (assuming that exim_uid and exim_gid
1837are not root). The third argument controls the running of initgroups().
1838Normally we do this, in order to set up the groups for the Exim user. However,
1839if we are not root at this time - some odd installations run that way - we
1840cannot do this. */
1841
1842exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1843
ebeaf996
PH
1844/* Update the originator_xxx fields so that received messages as listed as
1845coming from Exim, not whoever started the daemon. */
1846
1847originator_uid = exim_uid;
1848originator_gid = exim_gid;
f3ebb786
JH
1849originator_login = (pw = getpwuid(exim_uid))
1850 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
ebeaf996 1851
059ec3d9
PH
1852/* Get somewhere to keep the list of queue-runner pids if we are keeping track
1853of them (and also if we are doing queue runs). */
1854
0cd5fd23 1855if (queue_interval > 0 && local_queue_run_max > 0)
059ec3d9 1856 {
f3ebb786 1857 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t), FALSE);
d7978c0f 1858 for (int i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
059ec3d9
PH
1859 }
1860
01446a56
JH
1861/* Set up the handler for termination of child processes, and the one
1862telling us to die. */
059ec3d9
PH
1863
1864sigchld_seen = FALSE;
7d468ab8 1865os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
059ec3d9 1866
01446a56
JH
1867sigterm_seen = FALSE;
1868os_non_restarting_signal(SIGTERM, main_sigterm_handler);
1869
059ec3d9
PH
1870/* If we are to run the queue periodically, pretend the alarm has just gone
1871off. This will cause the first queue-runner to get kicked off straight away. */
1872
1873sigalrm_seen = (queue_interval > 0);
1874
1875/* Log the start up of a daemon - at least one of listening or queue running
1876must be set up. */
1877
8768d548 1878if (f.inetd_wait_mode)
9ee44efb
PP
1879 {
1880 uschar *p = big_buffer;
1881
1882 if (inetd_wait_timeout >= 0)
1883 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
1884 else
1885 sprintf(CS p, "with no wait timeout");
1886
1887 log_write(0, LOG_MAIN,
1888 "exim %s daemon started: pid=%d, launched with listening socket, %s",
1889 version_string, getpid(), big_buffer);
2f21487f 1890 set_process_info("daemon(%s): pre-listening socket", version_string);
9ee44efb
PP
1891
1892 /* set up the timeout logic */
ff966302 1893 sigalrm_seen = TRUE;
9ee44efb
PP
1894 }
1895
8768d548 1896else if (f.daemon_listen)
059ec3d9 1897 {
059ec3d9
PH
1898 int smtp_ports = 0;
1899 int smtps_ports = 0;
254f38d1
JH
1900 ip_address_item * ipa;
1901 uschar * p;
e37f8a84 1902 uschar * qinfo = queue_interval > 0
173de73b
JH
1903 ? string_sprintf("-q%s%s",
1904 f.queue_2stage ? "q" : "", readconf_printtime(queue_interval))
e37f8a84 1905 : US"no queue runs";
059ec3d9
PH
1906
1907 /* Build a list of listening addresses in big_buffer, but limit it to 10
1908 items. The style is for backwards compatibility.
1909
1910 It is now possible to have some ports listening for SMTPS (the old,
1911 deprecated protocol that starts TLS without using STARTTLS), and others
1912 listening for standard SMTP. Keep their listings separate. */
1913
254f38d1 1914 for (int j = 0, i; j < 2; j++)
059ec3d9 1915 {
e37f8a84 1916 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
b891534f
JH
1917 {
1918 /* First time round, look for SMTP ports; second time round, look for
254f38d1 1919 SMTPS ports. Build IP+port strings. */
b891534f
JH
1920
1921 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1922 {
1923 if (j == 0)
254f38d1 1924 smtp_ports++;
b891534f 1925 else
254f38d1 1926 smtps_ports++;
b891534f
JH
1927
1928 /* Now the information about the port (and sometimes interface) */
1929
1930 if (ipa->address[0] == ':' && ipa->address[1] == 0)
e4d0fc93 1931 { /* v6 wildcard */
b891534f
JH
1932 if (ipa->next && ipa->next->address[0] == 0 &&
1933 ipa->next->port == ipa->port)
1934 {
254f38d1
JH
1935 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
1936 (ipa = ipa->next)->log = NULL;
b891534f
JH
1937 }
1938 else if (ipa->v6_include_v4)
254f38d1 1939 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
b891534f 1940 else
254f38d1 1941 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
b891534f 1942 }
e4d0fc93 1943 else if (ipa->address[0] == 0) /* v4 wildcard */
254f38d1 1944 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
e4d0fc93 1945 else /* check for previously-seen IP */
b891534f 1946 {
254f38d1 1947 ip_address_item * i2;
e4d0fc93
JH
1948 for (i2 = addresses; i2 != ipa; i2 = i2->next)
1949 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
1950 && Ustrcmp(ipa->address, i2->address) == 0
1951 )
1952 { /* found; append port to list */
254f38d1
JH
1953 for (p = i2->log; *p; ) p++; /* end of existing string */
1954 if (*--p == '}') *p = '\0'; /* drop EOL */
1955 while (isdigit(*--p)) ; /* char before port */
1956
1957 i2->log = *p == ':' /* no list yet? */
1958 ? string_sprintf("%.*s{%s,%d}",
1959 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
1960 : string_sprintf("%s,%d}", i2->log, ipa->port);
1961 ipa->log = NULL;
e4d0fc93
JH
1962 break;
1963 }
1964 if (i2 == ipa) /* first-time IP */
254f38d1 1965 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
b891534f 1966 }
b891534f
JH
1967 }
1968 }
254f38d1 1969 }
059ec3d9 1970
254f38d1
JH
1971 p = big_buffer;
1972 for (int j = 0, i; j < 2; j++)
1973 {
1974 /* First time round, look for SMTP ports; second time round, look for
1975 SMTPS ports. For the first one of each, insert leading text. */
1976
1977 if (j == 0)
059ec3d9 1978 {
254f38d1
JH
1979 if (smtp_ports > 0)
1980 p += sprintf(CS p, "SMTP on");
059ec3d9 1981 }
254f38d1
JH
1982 else
1983 if (smtps_ports > 0)
1984 p += sprintf(CS p, "%sSMTPS on",
1985 smtp_ports == 0 ? "" : " and for ");
1986
1987 /* Now the information about the port (and sometimes interface) */
1988
1989 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
1990 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1991 if (ipa->log)
1992 p += sprintf(CS p, "%s", ipa->log);
1993
1994 if (ipa)
1995 p += sprintf(CS p, " ...");
059ec3d9
PH
1996 }
1997
1998 log_write(0, LOG_MAIN,
1999 "exim %s daemon started: pid=%d, %s, listening for %s",
2000 version_string, getpid(), qinfo, big_buffer);
44915474
JH
2001 set_process_info("daemon(%s): %s, listening for %s",
2002 version_string, qinfo, big_buffer);
059ec3d9
PH
2003 }
2004
2005else
2006 {
44915474
JH
2007 uschar * s = *queue_name
2008 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
2009 : string_sprintf("-q%s", readconf_printtime(queue_interval));
059ec3d9 2010 log_write(0, LOG_MAIN,
44915474
JH
2011 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
2012 version_string, getpid(), s);
2013 set_process_info("daemon(%s): %s, not listening", version_string, s);
059ec3d9
PH
2014 }
2015
476be7e2
JH
2016/* Do any work it might be useful to amortize over our children
2017(eg: compile regex) */
2018
476be7e2 2019dns_pattern_init();
d85cdeb5
JH
2020smtp_deliver_init(); /* Used for callouts */
2021
2022#ifndef DISABLE_DKIM
2023 {
2024# ifdef MEASURE_TIMING
2025 struct timeval t0;
2026 gettimeofday(&t0, NULL);
2027# endif
2028 dkim_exim_init();
2029# ifdef MEASURE_TIMING
2030 report_time_since(&t0, US"dkim_exim_init (delta)");
2031# endif
2032 }
2033#endif
476be7e2
JH
2034
2035#ifdef WITH_CONTENT_SCAN
2036malware_init();
2037#endif
73ec116f
JH
2038#ifdef SUPPORT_SPF
2039spf_init();
2040#endif
059ec3d9
PH
2041
2042/* Close the log so it can be renamed and moved. In the few cases below where
2043this long-running process writes to the log (always exceptional conditions), it
2044closes the log afterwards, for the same reason. */
2045
2046log_close_all();
2047
2048DEBUG(D_any) debug_print_ids(US"daemon running with");
2049
2050/* Any messages accepted via this route are going to be SMTP. */
2051
2052smtp_input = TRUE;
2053
9f01e50d
JH
2054#ifdef MEASURE_TIMING
2055report_time_since(&timestamp_startup, US"daemon loop start"); /* testcase 0022 */
2056#endif
2057
059ec3d9
PH
2058/* Enter the never-ending loop... */
2059
2060for (;;)
2061 {
2062 #if HAVE_IPV6
2063 struct sockaddr_in6 accepted;
2064 #else
2065 struct sockaddr_in accepted;
2066 #endif
2067
cf73943b 2068 EXIM_SOCKLEN_T len;
059ec3d9
PH
2069 pid_t pid;
2070
01446a56
JH
2071 if (sigterm_seen)
2072 daemon_die(); /* Does not return */
2073
059ec3d9 2074 /* This code is placed first in the loop, so that it gets obeyed at the
9ee44efb
PP
2075 start, before the first wait, for the queue-runner case, so that the first
2076 one can be started immediately.
2077
2078 The other option is that we have an inetd wait timeout specified to -bw. */
059ec3d9
PH
2079
2080 if (sigalrm_seen)
2081 {
9ee44efb
PP
2082 if (inetd_wait_timeout > 0)
2083 {
2084 time_t resignal_interval = inetd_wait_timeout;
2085
2086 if (last_connection_time == (time_t)0)
2087 {
2088 DEBUG(D_any)
2089 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
2090 }
2091 else
2092 {
2093 time_t now = time(NULL);
2094 if (now == (time_t)-1)
2095 {
2096 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
2097 }
2098 else
2099 {
2100 if ((now - last_connection_time) >= inetd_wait_timeout)
2101 {
2102 DEBUG(D_any)
2103 debug_printf("inetd wait timeout %d expired, ending daemon\n",
2104 inetd_wait_timeout);
2105 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
2106 version_string);
2107 exit(EXIT_SUCCESS);
2108 }
2109 else
2110 {
2111 resignal_interval -= (now - last_connection_time);
2112 }
2113 }
2114 }
059ec3d9 2115
9ee44efb 2116 sigalrm_seen = FALSE;
c2a1bba0 2117 ALARM(resignal_interval);
9ee44efb 2118 }
059ec3d9 2119
9ee44efb 2120 else
059ec3d9 2121 {
ff966302
JH
2122 DEBUG(D_any) debug_printf("%s received\n",
2123#ifdef EXPERIMENTAL_QUEUE_RAMP
2124 *queuerun_msgid ? "qrun notification" :
2125#endif
2126 "SIGALRM");
8e669ac1 2127
9ee44efb
PP
2128 /* Do a full queue run in a child process, if required, unless we already
2129 have enough queue runners on the go. If we are not running as root, a
2130 re-exec is required. */
059ec3d9 2131
96c81511
JH
2132 if ( queue_interval > 0
2133 && (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
9ee44efb 2134 {
4b01271f 2135 if ((pid = exim_fork(US"queue-runner")) == 0)
9ee44efb 2136 {
9ee44efb
PP
2137 /* Disable debugging if it's required only for the daemon process. We
2138 leave the above message, because it ties up with the "child ended"
2139 debugging messages. */
059ec3d9 2140
8768d548 2141 if (f.debug_daemon) debug_selector = 0;
059ec3d9 2142
9ee44efb 2143 /* Close any open listening sockets in the child */
059ec3d9 2144
8cfc4d82
JH
2145 close_daemon_sockets(daemon_notifier_fd,
2146 listen_sockets, listen_socket_count);
059ec3d9 2147
9ee44efb 2148 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
059ec3d9 2149
9ee44efb
PP
2150 signal(SIGHUP, SIG_DFL);
2151 signal(SIGCHLD, SIG_DFL);
01446a56 2152 signal(SIGTERM, SIG_DFL);
059ec3d9 2153
9ee44efb
PP
2154 /* Re-exec if privilege has been given up, unless deliver_drop_
2155 privilege is set. Reset SIGALRM before exec(). */
4fbcfc2e 2156
9ee44efb 2157 if (geteuid() != root_uid && !deliver_drop_privilege)
4fbcfc2e 2158 {
9ee44efb
PP
2159 uschar opt[8];
2160 uschar *p = opt;
ff966302 2161 uschar *extra[7];
9ee44efb
PP
2162 int extracount = 1;
2163
2164 signal(SIGALRM, SIG_DFL);
2165 *p++ = '-';
2166 *p++ = 'q';
ff966302
JH
2167 if ( f.queue_2stage
2168#ifdef EXPERIMENTAL_QUEUE_RAMP
2169 && !*queuerun_msgid
2170#endif
2171 ) *p++ = 'q';
8768d548
JH
2172 if (f.queue_run_first_delivery) *p++ = 'i';
2173 if (f.queue_run_force) *p++ = 'f';
2174 if (f.deliver_force_thaw) *p++ = 'f';
2175 if (f.queue_run_local) *p++ = 'l';
9ee44efb 2176 *p = 0;
3f008c60 2177 extra[0] = *queue_name
e37f8a84 2178 ? string_sprintf("%sG%s", opt, queue_name) : opt;
9ee44efb 2179
ff966302
JH
2180#ifdef EXPERIMENTAL_QUEUE_RAMP
2181 if (*queuerun_msgid)
2182 {
6641ba45 2183 log_write(0, LOG_MAIN, "notify triggered queue run");
ff966302
JH
2184 extra[extracount++] = queuerun_msgid; /* Trigger only the */
2185 extra[extracount++] = queuerun_msgid; /* one message */
2186 }
2187#endif
2188
9ee44efb
PP
2189 /* If -R or -S were on the original command line, ensure they get
2190 passed on. */
2191
e37f8a84 2192 if (deliver_selectstring)
9ee44efb 2193 {
8768d548 2194 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
9ee44efb
PP
2195 extra[extracount++] = deliver_selectstring;
2196 }
2197
e37f8a84 2198 if (deliver_selectstring_sender)
9ee44efb 2199 {
8768d548 2200 extra[extracount++] = f.deliver_selectstring_sender_regex
e37f8a84 2201 ? US"-Sr" : US"-S";
9ee44efb
PP
2202 extra[extracount++] = deliver_selectstring_sender;
2203 }
2204
2205 /* Overlay this process with a new execution. */
2206
ff966302
JH
2207 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
2208 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
9ee44efb
PP
2209
2210 /* Control never returns here. */
4fbcfc2e
PH
2211 }
2212
9ee44efb 2213 /* No need to re-exec; SIGALRM remains set to the default handler */
059ec3d9 2214
ff966302
JH
2215#ifdef EXPERIMENTAL_QUEUE_RAMP
2216 if (*queuerun_msgid)
2217 {
6641ba45 2218 log_write(0, LOG_MAIN, "notify triggered queue run");
ff966302
JH
2219 f.queue_2stage = FALSE;
2220 queue_run(queuerun_msgid, queuerun_msgid, FALSE);
2221 }
2222 else
2223#endif
2224 queue_run(NULL, NULL, FALSE);
81022793 2225 exim_underbar_exit(EXIT_SUCCESS);
059ec3d9
PH
2226 }
2227
9ee44efb 2228 if (pid < 0)
059ec3d9 2229 {
9ee44efb
PP
2230 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
2231 "process failed: %s", strerror(errno));
2232 log_close_all();
2233 }
2234 else
2235 {
d7978c0f 2236 for (int i = 0; i < local_queue_run_max; ++i)
9ee44efb
PP
2237 if (queue_pid_slots[i] <= 0)
2238 {
2239 queue_pid_slots[i] = pid;
2240 queue_run_count++;
2241 break;
2242 }
9ee44efb 2243 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
d7978c0f 2244 queue_run_count, queue_run_count == 1 ? "" : "es");
059ec3d9 2245 }
059ec3d9 2246 }
059ec3d9 2247
9ee44efb 2248 /* Reset the alarm clock */
059ec3d9 2249
9ee44efb 2250 sigalrm_seen = FALSE;
ff966302
JH
2251#ifdef EXPERIMENTAL_QUEUE_RAMP
2252 if (*queuerun_msgid)
2253 *queuerun_msgid = 0;
2254 else
2255#endif
2256 ALARM(queue_interval);
9ee44efb
PP
2257 }
2258
2259 } /* sigalrm_seen */
059ec3d9
PH
2260
2261
2262 /* Sleep till a connection happens if listening, and handle the connection if
2263 that is why we woke up. The FreeBSD operating system requires the use of
2264 select() before accept() because the latter function is not interrupted by
2265 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2266 OS do notice signals in accept() but it does no harm to have the select()
2267 in for all of them - and it won't then be a lurking problem for ports to
2268 new OS. In fact, the later addition of listening on specific interfaces only
2269 requires this way of working anyway. */
2270
8768d548 2271 if (f.daemon_listen)
059ec3d9 2272 {
d7978c0f 2273 int lcount, select_errno;
059ec3d9
PH
2274 int max_socket = 0;
2275 BOOL select_failed = FALSE;
2276 fd_set select_listen;
2277
2278 FD_ZERO(&select_listen);
ff966302
JH
2279 if (daemon_notifier_fd >= 0)
2280 FD_SET(daemon_notifier_fd, &select_listen);
d7978c0f 2281 for (int sk = 0; sk < listen_socket_count; sk++)
059ec3d9
PH
2282 {
2283 FD_SET(listen_sockets[sk], &select_listen);
2284 if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk];
2285 }
2286
2287 DEBUG(D_any) debug_printf("Listening...\n");
8e669ac1
PH
2288
2289 /* In rare cases we may have had a SIGCHLD signal in the time between
2290 setting the handler (below) and getting back here. If so, pretend that the
7d468ab8 2291 select() was interrupted so that we reap the child. This might still leave
8e669ac1 2292 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
7d468ab8
PH
2293 only to do the reaping more quickly, it shouldn't result in anything other
2294 than a delay until something else causes a wake-up. */
2295
2296 if (sigchld_seen)
2297 {
2298 lcount = -1;
8e669ac1 2299 errno = EINTR;
7d468ab8
PH
2300 }
2301 else
7d468ab8
PH
2302 lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen,
2303 NULL, NULL, NULL);
059ec3d9 2304
7d468ab8 2305 if (lcount < 0)
059ec3d9
PH
2306 {
2307 select_failed = TRUE;
2308 lcount = 1;
2309 }
8e669ac1
PH
2310
2311 /* Clean up any subprocesses that may have terminated. We need to do this
2312 here so that smtp_accept_max_per_host works when a connection to that host
2313 has completed, and we are about to accept a new one. When this code was
2314 later in the sequence, a new connection could be rejected, even though an
2315 old one had just finished. Preserve the errno from any select() failure for
bb6e88ff 2316 the use of the common select/accept error processing below. */
8e669ac1 2317
bb6e88ff
PH
2318 select_errno = errno;
2319 handle_ending_processes();
8e669ac1
PH
2320 errno = select_errno;
2321
01603eec 2322#ifndef DISABLE_TLS
b10c87b3
JH
2323 /* Create or rotate any required keys */
2324 tls_daemon_init();
2325#endif
2326
059ec3d9 2327 /* Loop for all the sockets that are currently ready to go. If select
7d468ab8
PH
2328 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2329 to use the common error code for select/accept below. */
059ec3d9
PH
2330
2331 while (lcount-- > 0)
2332 {
2333 int accept_socket = -1;
6851a9c5 2334
059ec3d9 2335 if (!select_failed)
ff966302 2336 {
ff966302
JH
2337 if ( daemon_notifier_fd >= 0
2338 && FD_ISSET(daemon_notifier_fd, &select_listen))
2339 {
2340 FD_CLR(daemon_notifier_fd, &select_listen);
2341 sigalrm_seen = daemon_notification();
2342 break; /* to top of daemon loop */
2343 }
d7978c0f 2344 for (int sk = 0; sk < listen_socket_count; sk++)
059ec3d9
PH
2345 if (FD_ISSET(listen_sockets[sk], &select_listen))
2346 {
cf73943b 2347 len = sizeof(accepted);
059ec3d9
PH
2348 accept_socket = accept(listen_sockets[sk],
2349 (struct sockaddr *)&accepted, &len);
2350 FD_CLR(listen_sockets[sk], &select_listen);
2351 break;
2352 }
ff966302 2353 }
059ec3d9
PH
2354
2355 /* If select or accept has failed and this was not caused by an
2356 interruption, log the incident and try again. With asymmetric TCP/IP
2357 routing errors such as "No route to network" have been seen here. Also
2358 "connection reset by peer" has been seen. These cannot be classed as
2359 disastrous errors, but they could fill up a lot of log. The code in smail
2360 crashes the daemon after 10 successive failures of accept, on the grounds
2361 that some OS fail continuously. Exim originally followed suit, but this
2362 appears to have caused problems. Now it just keeps going, but instead of
2363 logging each error, it batches them up when they are continuous. */
2364
2365 if (accept_socket < 0 && errno != EINTR)
2366 {
2367 if (accept_retry_count == 0)
2368 {
2369 accept_retry_errno = errno;
2370 accept_retry_select_failed = select_failed;
2371 }
2372 else
2373 {
2374 if (errno != accept_retry_errno ||
2375 select_failed != accept_retry_select_failed ||
2376 accept_retry_count >= 50)
2377 {
2378 log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0),
2379 "%d %s() failure%s: %s",
2380 accept_retry_count,
2381 accept_retry_select_failed? "select" : "accept",
2382 (accept_retry_count == 1)? "" : "s",
2383 strerror(accept_retry_errno));
2384 log_close_all();
2385 accept_retry_count = 0;
2386 accept_retry_errno = errno;
2387 accept_retry_select_failed = select_failed;
2388 }
2389 }
2390 accept_retry_count++;
2391 }
2392
2393 else
2394 {
2395 if (accept_retry_count > 0)
2396 {
2397 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2398 accept_retry_count,
2399 accept_retry_select_failed? "select" : "accept",
2400 (accept_retry_count == 1)? "" : "s",
2401 strerror(accept_retry_errno));
2402 log_close_all();
2403 accept_retry_count = 0;
2404 }
2405 }
2406
2407 /* If select/accept succeeded, deal with the connection. */
2408
2409 if (accept_socket >= 0)
9ee44efb
PP
2410 {
2411 if (inetd_wait_timeout)
2412 last_connection_time = time(NULL);
059ec3d9
PH
2413 handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,
2414 (struct sockaddr *)&accepted);
9ee44efb 2415 }
059ec3d9
PH
2416 }
2417 }
2418
2419 /* If not listening, then just sleep for the queue interval. If we woke
2420 up early the last time for some other signal, it won't matter because
2421 the alarm signal will wake at the right time. This code originally used
2422 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2423 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2424 select() can be used as an interruptible sleep() on all versions of Unix. */
2425
2426 else
2427 {
2428 struct timeval tv;
2429 tv.tv_sec = queue_interval;
2430 tv.tv_usec = 0;
2431 select(0, NULL, NULL, NULL, &tv);
8e669ac1 2432 handle_ending_processes();
059ec3d9
PH
2433 }
2434
2435 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2436 for itself, because it isn't doing the waiting itself. */
2437
2438 if (sigchld_seen)
2439 {
2440 sigchld_seen = FALSE;
7d468ab8 2441 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
059ec3d9
PH
2442 }
2443
2444 /* Handle being woken by SIGHUP. We know at this point that the result
2445 of accept() has been dealt with, so we can re-exec exim safely, first
2446 closing the listening sockets so that they can be reused. Cancel any pending
2447 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2448 that another HUP in quick succession doesn't clobber the new daemon before it
2449 gets going. All log files get closed by the close-on-exec flag; however, if
2450 the exec fails, we need to close the logs. */
2451
2452 if (sighup_seen)
2453 {
059ec3d9
PH
2454 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2455 getpid());
8cfc4d82
JH
2456 close_daemon_sockets(daemon_notifier_fd,
2457 listen_sockets, listen_socket_count);
c2a1bba0 2458 ALARM_CLR(0);
059ec3d9
PH
2459 signal(SIGHUP, SIG_IGN);
2460 sighup_argv[0] = exim_path;
2461 exim_nullstd();
2462 execv(CS exim_path, (char *const *)sighup_argv);
2463 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2464 getpid(), exim_path, strerror(errno));
2465 log_close_all();
2466 }
2467
2468 } /* End of main loop */
2469
2470/* Control never reaches here */
2471}
2472
071c51f7
JH
2473/* vi: aw ai sw=2
2474*/
059ec3d9 2475/* End of exim_daemon.c */