1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) The Exim Maintainers 2020 - 2022 */
6 /* Copyright (c) University of Cambridge 1995 - 2023 */
7 /* See the file NOTICE for conditions of use and distribution. */
8 /* SPDX-License-Identifier: GPL-2.0-or-later */
10 /* Functions concerned with running Exim as a daemon */
16 /* Structure for holding data for each SMTP connection */
18 typedef struct smtp_slot {
19 pid_t pid; /* pid of the spawned reception process */
20 uschar * host_address; /* address of the client host */
23 typedef struct runner_slot {
24 pid_t pid; /* pid of spawned queue-runner process */
25 const uschar *queue_name; /* pointer to the name in the qrunner struct */
28 /* An empty slot for initializing (Standard C does not allow constructor
29 expressions in assignments except as initializers in declarations). */
31 static smtp_slot empty_smtp_slot = { .pid = 0, .host_address = NULL };
33 /*************************************************
34 * Local static variables *
35 *************************************************/
37 static SIGNAL_BOOL sigchld_seen;
38 static SIGNAL_BOOL sighup_seen;
39 static SIGNAL_BOOL sigterm_seen;
41 static int accept_retry_count = 0;
42 static int accept_retry_errno;
43 static BOOL accept_retry_select_failed;
45 static int queue_run_count = 0; /* current runners */
47 static unsigned queue_runner_slot_count = 0;
48 static runner_slot * queue_runner_slots = NULL;
49 static smtp_slot * smtp_slots = NULL;
51 static BOOL write_pid = TRUE;
53 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
54 static uschar * notifier_socket_name;
58 /*************************************************
60 *************************************************/
62 /* All this handler does is to set a flag and re-enable the signal.
64 Argument: the signal number
69 sighup_handler(int sig)
72 signal(SIGHUP, sighup_handler);
77 /*************************************************
78 * SIGCHLD handler for main daemon process *
79 *************************************************/
81 /* Don't re-enable the handler here, since we aren't doing the
82 waiting here. If the signal is re-enabled, there will just be an
83 infinite sequence of calls to this handler. The SIGCHLD signal is
84 used just as a means of waking up the daemon so that it notices
85 terminated subprocesses as soon as possible.
87 Argument: the signal number
92 main_sigchld_handler(int sig)
94 os_non_restarting_signal(SIGCHLD, SIG_DFL);
99 /* SIGTERM handler. Try to get the daemon pid file removed
103 main_sigterm_handler(int sig)
111 /*************************************************
112 * Unexpected errors in SMTP calls *
113 *************************************************/
115 /* This function just saves a bit of repetitious coding.
118 log_msg Text of message to be logged
119 smtp_msg Text of SMTP error message
120 was_errno The failing errno
126 never_error(uschar *log_msg, uschar *smtp_msg, int was_errno)
128 uschar *emsg = was_errno <= 0
129 ? US"" : string_sprintf(": %s", strerror(was_errno));
130 log_write(0, LOG_MAIN|LOG_PANIC, "%s%s", log_msg, emsg);
131 if (smtp_out) smtp_printf("421 %s\r\n", FALSE, smtp_msg);
137 /*************************************************
138 *************************************************/
141 unlink_notifier_socket(void)
143 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
144 DEBUG(D_any) debug_printf("unlinking notifier socket %s\n", notifier_socket_name);
145 Uunlink(notifier_socket_name);
151 close_daemon_sockets(int daemon_notifier_fd,
152 struct pollfd * fd_polls, int listen_socket_count)
154 if (daemon_notifier_fd >= 0)
156 (void) close(daemon_notifier_fd);
157 daemon_notifier_fd = -1;
160 for (int i = 0; i < listen_socket_count; i++) (void) close(fd_polls[i].fd);
164 /*************************************************
165 * Handle a connected SMTP call *
166 *************************************************/
168 /* This function is called when an SMTP connection has been accepted.
169 If there are too many, give an error message and close down. Otherwise
170 spin off a sub-process to handle the call. The list of listening sockets
171 is required so that they can be closed in the sub-process. Take care not to
172 leak store in this process - reset the stacking pool at the end.
175 fd_polls sockets which are listening for incoming calls
176 listen_socket_count count of listening sockets
177 accept_socket socket of the current accepted call
178 accepted socket information about the current call
184 handle_smtp_call(struct pollfd *fd_polls, int listen_socket_count,
185 int accept_socket, struct sockaddr *accepted)
188 union sockaddr_46 interface_sockaddr;
189 EXIM_SOCKLEN_T ifsize = sizeof(interface_sockaddr);
190 int dup_accept_socket = -1;
191 int max_for_this_host = 0;
192 int save_log_selector = *log_selector;
195 rmark reset_point = store_mark();
197 /* Make the address available in ASCII representation, and also fish out
200 sender_host_address = host_ntoa(-1, accepted, NULL, &sender_host_port);
201 DEBUG(D_any) debug_printf("Connection request from %s port %d\n",
202 sender_host_address, sender_host_port);
204 /* Set up the output stream, check the socket has duplicated, and set up the
205 input stream. These operations fail only the exceptional circumstances. Note
206 that never_error() won't use smtp_out if it is NULL. */
208 if (!(smtp_out = fdopen(accept_socket, "wb")))
210 never_error(US"daemon: fdopen() for smtp_out failed", US"", errno);
214 if ((dup_accept_socket = dup(accept_socket)) < 0)
216 never_error(US"daemon: couldn't dup socket descriptor",
217 US"Connection setup failed", errno);
221 if (!(smtp_in = fdopen(dup_accept_socket, "rb")))
223 never_error(US"daemon: fdopen() for smtp_in failed",
224 US"Connection setup failed", errno);
228 /* Get the data for the local interface address. Panic for most errors, but
229 "connection reset by peer" just means the connection went away. */
231 if (getsockname(accept_socket, (struct sockaddr *)(&interface_sockaddr),
234 log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC),
235 "getsockname() failed: %s", strerror(errno));
236 smtp_printf("421 Local problem: getsockname() failed; please try again later\r\n", FALSE);
240 interface_address = host_ntoa(-1, &interface_sockaddr, NULL, &interface_port);
241 DEBUG(D_interface) debug_printf("interface address=%s port=%d\n",
242 interface_address, interface_port);
244 /* Build a string identifying the remote host and, if requested, the port and
245 the local interface data. This is for logging; at the end of this function the
246 memory is reclaimed. */
248 whofrom = string_append(NULL, 3, "[", sender_host_address, "]");
250 if (LOGGING(incoming_port))
251 whofrom = string_fmt_append(whofrom, ":%d", sender_host_port);
253 if (LOGGING(incoming_interface))
254 whofrom = string_fmt_append(whofrom, " I=[%s]:%d",
255 interface_address, interface_port);
257 (void) string_from_gstring(whofrom); /* Terminate the newly-built string */
259 /* Check maximum number of connections. We do not check for reserved
260 connections or unacceptable hosts here. That is done in the subprocess because
261 it might take some time. */
263 if (smtp_accept_max > 0 && smtp_accept_count >= smtp_accept_max)
265 DEBUG(D_any) debug_printf("rejecting SMTP connection: count=%d max=%d\n",
266 smtp_accept_count, smtp_accept_max);
267 smtp_printf("421 Too many concurrent SMTP connections; "
268 "please try again later.\r\n", FALSE);
269 log_write(L_connection_reject,
270 LOG_MAIN, "Connection from %s refused: too many connections",
275 /* If a load limit above which only reserved hosts are acceptable is defined,
276 get the load average here, and if there are in fact no reserved hosts, do
277 the test right away (saves a fork). If there are hosts, do the check in the
278 subprocess because it might take time. */
280 if (smtp_load_reserve >= 0)
282 load_average = OS_GETLOADAVG();
283 if (!smtp_reserve_hosts && load_average > smtp_load_reserve)
285 DEBUG(D_any) debug_printf("rejecting SMTP connection: load average = %.2f\n",
286 (double)load_average/1000.0);
287 smtp_printf("421 Too much load; please try again later.\r\n", FALSE);
288 log_write(L_connection_reject,
289 LOG_MAIN, "Connection from %s refused: load average = %.2f",
290 whofrom->s, (double)load_average/1000.0);
295 /* Check that one specific host (strictly, IP address) is not hogging
296 resources. This is done here to prevent a denial of service attack by someone
297 forcing you to fork lots of times before denying service. The value of
298 smtp_accept_max_per_host is a string which is expanded. This makes it possible
299 to provide host-specific limits according to $sender_host address, but because
300 this is in the daemon mainline, only fast expansions (such as inline address
301 checks) should be used. The documentation is full of warnings. */
303 if (smtp_accept_max_per_host)
305 uschar *expanded = expand_string(smtp_accept_max_per_host);
308 if (!f.expand_string_forcedfail)
309 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
310 "failed for %s: %s", whofrom->s, expand_string_message);
312 /* For speed, interpret a decimal number inline here */
315 uschar *s = expanded;
317 max_for_this_host = max_for_this_host * 10 + *s++ - '0';
319 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
320 "for %s contains non-digit: %s", whofrom->s, expanded);
324 /* If we have fewer connections than max_for_this_host, we can skip the tedious
325 per host_address checks. Note that at this stage smtp_accept_count contains the
326 count of *other* connections, not including this one. */
328 if (max_for_this_host > 0 && smtp_accept_count >= max_for_this_host)
330 int host_accept_count = 0;
331 int other_host_count = 0; /* keep a count of non matches to optimise */
333 for (int i = 0; i < smtp_accept_max; ++i)
334 if (smtp_slots[i].host_address)
336 if (Ustrcmp(sender_host_address, smtp_slots[i].host_address) == 0)
341 /* Testing all these strings is expensive - see if we can drop out
342 early, either by hitting the target, or finding there are not enough
343 connections left to make the target. */
345 if ( host_accept_count >= max_for_this_host
346 || smtp_accept_count - other_host_count < max_for_this_host)
350 if (host_accept_count >= max_for_this_host)
352 DEBUG(D_any) debug_printf("rejecting SMTP connection: too many from this "
353 "IP address: count=%d max=%d\n",
354 host_accept_count, max_for_this_host);
355 smtp_printf("421 Too many concurrent SMTP connections "
356 "from this IP address; please try again later.\r\n", FALSE);
357 log_write(L_connection_reject,
358 LOG_MAIN, "Connection from %s refused: too many connections "
359 "from that IP address", whofrom->s);
365 /* OK, the connection count checks have been passed. Before we can fork the
366 accepting process, we must first log the connection if requested. This logging
367 used to happen in the subprocess, but doing that means that the value of
368 smtp_accept_count can be out of step by the time it is logged. So we have to do
369 the logging here and accept the performance cost. Note that smtp_accept_count
370 hasn't yet been incremented to take account of this connection.
372 In order to minimize the cost (because this is going to happen for every
373 connection), do a preliminary selector test here. This saves ploughing through
374 the generalized logging code each time when the selector is false. If the
375 selector is set, check whether the host is on the list for logging. If not,
376 arrange to unset the selector in the subprocess. */
378 if (LOGGING(smtp_connection))
380 uschar *list = hosts_connection_nolog;
381 memset(sender_host_cache, 0, sizeof(sender_host_cache));
382 if (list && verify_check_host(&list) == OK)
383 save_log_selector &= ~L_smtp_connection;
385 log_write(L_smtp_connection, LOG_MAIN, "SMTP connection from %s "
386 "(TCP/IP connection count = %d)", whofrom->s, smtp_accept_count + 1);
389 /* Now we can fork the accepting process; do a lookup tidy, just in case any
390 expansion above did a lookup. */
393 pid = exim_fork(US"daemon-accept");
395 /* Handle the child process */
399 int queue_only_reason = 0;
400 int old_pool = store_pool;
401 int save_debug_selector = debug_selector;
402 BOOL local_queue_only;
403 BOOL session_local_queue_only;
405 struct sigaction act;
408 smtp_accept_count++; /* So that it includes this process */
410 /* If the listen backlog was over the monitoring level, log it. */
412 if (smtp_listen_backlog > smtp_backlog_monitor)
413 log_write(0, LOG_MAIN, "listen backlog %d I=[%s]:%d",
414 smtp_listen_backlog, interface_address, interface_port);
416 /* May have been modified for the subprocess */
418 *log_selector = save_log_selector;
420 /* Get the local interface address into permanent store */
422 store_pool = POOL_PERM;
423 interface_address = string_copy(interface_address);
424 store_pool = old_pool;
426 /* Check for a tls-on-connect port */
428 if (host_is_tls_on_connect_port(interface_port)) tls_in.on_connect = TRUE;
430 /* Expand smtp_active_hostname if required. We do not do this any earlier,
431 because it may depend on the local interface address (indeed, that is most
432 likely what it depends on.) */
434 smtp_active_hostname = primary_hostname;
435 if (raw_active_hostname)
437 uschar * nah = expand_string(raw_active_hostname);
440 if (!f.expand_string_forcedfail)
442 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand \"%s\" "
443 "(smtp_active_hostname): %s", raw_active_hostname,
444 expand_string_message);
445 smtp_printf("421 Local configuration error; "
446 "please try again later.\r\n", FALSE);
449 exim_underbar_exit(EXIT_FAILURE);
452 else if (*nah) smtp_active_hostname = nah;
455 /* Initialize the queueing flags */
458 session_local_queue_only = queue_only;
460 /* Close the listening sockets, and set the SIGCHLD handler to SIG_IGN.
461 We also attempt to set things up so that children are automatically reaped,
462 but just in case this isn't available, there's a paranoid waitpid() in the
463 loop too (except for systems where we are sure it isn't needed). See the more
464 extensive comment before the reception loop in exim.c for a fuller
465 explanation of this logic. */
467 close_daemon_sockets(daemon_notifier_fd, fd_polls, listen_socket_count);
469 /* Set FD_CLOEXEC on the SMTP socket. We don't want any rogue child processes
470 to be able to communicate with them, under any circumstances. */
471 (void)fcntl(accept_socket, F_SETFD,
472 fcntl(accept_socket, F_GETFD) | FD_CLOEXEC);
473 (void)fcntl(dup_accept_socket, F_SETFD,
474 fcntl(dup_accept_socket, F_GETFD) | FD_CLOEXEC);
477 act.sa_handler = SIG_IGN;
478 sigemptyset(&(act.sa_mask));
479 act.sa_flags = SA_NOCLDWAIT;
480 sigaction(SIGCHLD, &act, NULL);
482 signal(SIGCHLD, SIG_IGN);
484 signal(SIGTERM, SIG_DFL);
485 signal(SIGINT, SIG_DFL);
487 /* Attempt to get an id from the sending machine via the RFC 1413
488 protocol. We do this in the sub-process in order not to hold up the
489 main process if there is any delay. Then set up the fullhost information
490 in case there is no HELO/EHLO.
492 If debugging is enabled only for the daemon, we must turn if off while
493 finding the id, but turn it on again afterwards so that information about the
494 incoming connection is output. */
496 if (f.debug_daemon) debug_selector = 0;
497 verify_get_ident(IDENT_PORT);
498 host_build_sender_fullhost();
499 debug_selector = save_debug_selector;
502 debug_printf("Process %d is handling incoming connection from %s\n",
503 (int)getpid(), sender_fullhost);
505 /* Now disable debugging permanently if it's required only for the daemon
508 if (f.debug_daemon) debug_selector = 0;
510 /* If there are too many child processes for immediate delivery,
511 set the session_local_queue_only flag, which is initialized from the
512 configured value and may therefore already be TRUE. Leave logging
513 till later so it will have a message id attached. Note that there is no
514 possibility of re-calculating this per-message, because the value of
515 smtp_accept_count does not change in this subprocess. */
517 if (smtp_accept_queue > 0 && smtp_accept_count > smtp_accept_queue)
519 session_local_queue_only = TRUE;
520 queue_only_reason = 1;
523 /* Handle the start of the SMTP session, then loop, accepting incoming
524 messages from the SMTP connection. The end will come at the QUIT command,
525 when smtp_setup_msg() returns 0. A break in the connection causes the
526 process to die (see accept.c).
528 NOTE: We do *not* call smtp_log_no_mail() if smtp_start_session() fails,
529 because a log line has already been written for all its failure exists
530 (usually "connection refused: <reason>") and writing another one is
531 unnecessary clutter. */
533 if (!smtp_start_session())
537 exim_underbar_exit(EXIT_SUCCESS);
543 message_id[0] = 0; /* Clear out any previous message_id */
544 reset_point = store_mark(); /* Save current store high water point */
547 debug_printf("Process %d is ready for new message\n", (int)getpid());
549 /* Smtp_setup_msg() returns 0 on QUIT or if the call is from an
550 unacceptable host or if an ACL "drop" command was triggered, -1 on
551 connection lost, and +1 on validly reaching DATA. Receive_msg() almost
552 always returns TRUE when smtp_input is true; just retry if no message was
553 accepted (can happen for invalid message parameters). However, it can yield
554 FALSE if the connection was forcibly dropped by the DATA ACL. */
556 if ((rc = smtp_setup_msg()) > 0)
558 BOOL ok = receive_msg(FALSE);
559 search_tidyup(); /* Close cached databases */
560 if (!ok) /* Connection was dropped */
562 cancel_cutthrough_connection(TRUE, US"receive dropped");
564 smtp_log_no_mail(); /* Log no mail if configured */
565 exim_underbar_exit(EXIT_SUCCESS);
567 if (message_id[0] == 0) continue; /* No message was accepted */
569 else /* bad smtp_setup_msg() */
573 int fd = fileno(smtp_in);
577 /* drain socket, for clean TCP FINs */
578 if (fcntl(fd, F_SETFL, O_NONBLOCK) == 0)
579 for(int i = 16; read(fd, buf, sizeof(buf)) > 0 && i > 0; ) i--;
581 cancel_cutthrough_connection(TRUE, US"message setup dropped");
583 smtp_log_no_mail(); /* Log no mail if configured */
585 /*XXX should we pause briefly, hoping that the client will be the
586 active TCP closer hence get the TCP_WAIT endpoint? */
587 DEBUG(D_receive) debug_printf("SMTP>>(close on process exit)\n");
588 exim_underbar_exit(rc ? EXIT_FAILURE : EXIT_SUCCESS);
591 /* Show the recipients when debugging */
596 debug_printf("Sender: %s\n", sender_address);
599 debug_printf("Recipients:\n");
600 for (int i = 0; i < recipients_count; i++)
601 debug_printf(" %s\n", recipients_list[i].address);
605 /* A message has been accepted. Clean up any previous delivery processes
606 that have completed and are defunct, on systems where they don't go away
607 by themselves (see comments when setting SIG_IGN above). On such systems
608 (if any) these delivery processes hang around after termination until
609 the next message is received. */
611 #ifndef SIG_IGN_WORKS
612 while (waitpid(-1, NULL, WNOHANG) > 0);
615 /* Reclaim up the store used in accepting this message */
618 int r = receive_messagecount;
619 BOOL q = f.queue_only_policy;
620 smtp_reset(reset_point);
622 f.queue_only_policy = q;
623 receive_messagecount = r;
626 /* If queue_only is set or if there are too many incoming connections in
627 existence, session_local_queue_only will be TRUE. If it is not, check
628 whether we have received too many messages in this session for immediate
631 if (!session_local_queue_only &&
632 smtp_accept_queue_per_connection > 0 &&
633 receive_messagecount > smtp_accept_queue_per_connection)
635 session_local_queue_only = TRUE;
636 queue_only_reason = 2;
639 /* Initialize local_queue_only from session_local_queue_only. If it is not
640 true, and queue_only_load is set, check that the load average is below it.
641 If local_queue_only is set by this means, we also set if for the session if
642 queue_only_load_latch is true (the default). This means that, once set,
643 local_queue_only remains set for any subsequent messages on the same SMTP
644 connection. This is a deliberate choice; even though the load average may
645 fall, it doesn't seem right to deliver later messages on the same call when
646 not delivering earlier ones. However, the are special circumstances such as
647 very long-lived connections from scanning appliances where this is not the
648 best strategy. In such cases, queue_only_load_latch should be set false. */
650 if ( !(local_queue_only = session_local_queue_only)
651 && queue_only_load >= 0
652 && (local_queue_only = (load_average = OS_GETLOADAVG()) > queue_only_load)
655 queue_only_reason = 3;
656 if (queue_only_load_latch) session_local_queue_only = TRUE;
659 /* Log the queueing here, when it will get a message id attached, but
660 not if queue_only is set (case 0). */
662 if (local_queue_only) switch(queue_only_reason)
664 case 1: log_write(L_delay_delivery,
665 LOG_MAIN, "no immediate delivery: too many connections "
666 "(%d, max %d)", smtp_accept_count, smtp_accept_queue);
669 case 2: log_write(L_delay_delivery,
670 LOG_MAIN, "no immediate delivery: more than %d messages "
671 "received in one connection", smtp_accept_queue_per_connection);
674 case 3: log_write(L_delay_delivery,
675 LOG_MAIN, "no immediate delivery: load average %.2f",
676 (double)load_average/1000.0);
680 /* If a delivery attempt is required, spin off a new process to handle it.
681 If we are not root, we have to re-exec exim unless deliveries are being
682 done unprivileged. */
684 else if ( (!f.queue_only_policy || f.queue_smtp)
685 && !f.deliver_freeze)
689 /* We used to flush smtp_out before forking so that buffered data was not
690 duplicated, but now we want to pipeline the responses for data and quit.
691 Instead, hard-close the fd underlying smtp_out right after fork to discard
694 if ((dpid = exim_fork(US"daemon-accept-delivery")) == 0)
696 (void)fclose(smtp_in);
697 (void)close(fileno(smtp_out));
698 (void)fclose(smtp_out);
699 smtp_in = smtp_out = NULL;
701 /* Don't ever molest the parent's SSL connection, but do clean up
702 the data structures if necessary. */
705 tls_close(NULL, TLS_NO_SHUTDOWN);
708 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
710 signal(SIGHUP, SIG_DFL);
711 signal(SIGCHLD, SIG_DFL);
712 signal(SIGTERM, SIG_DFL);
713 signal(SIGINT, SIG_DFL);
715 if (geteuid() != root_uid && !deliver_drop_privilege)
717 signal(SIGALRM, SIG_DFL);
718 delivery_re_exec(CEE_EXEC_PANIC);
719 /* Control does not return here. */
722 /* No need to re-exec; SIGALRM remains set to the default handler */
724 (void) deliver_message(message_id, FALSE, FALSE);
726 exim_underbar_exit(EXIT_SUCCESS);
731 release_cutthrough_connection(US"passed for delivery");
732 DEBUG(D_any) debug_printf("forked delivery process %d\n", (int)dpid);
736 cancel_cutthrough_connection(TRUE, US"delivery fork failed");
737 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: delivery process fork "
738 "failed: %s", strerror(errno));
745 /* Carrying on in the parent daemon process... Can't do much if the fork
746 failed. Otherwise, keep count of the number of accepting processes and
747 remember the pid for ticking off when the child completes. */
750 never_error(US"daemon: accept process fork failed", US"Fork failed", errno);
753 for (int i = 0; i < smtp_accept_max; ++i)
754 if (smtp_slots[i].pid <= 0)
756 smtp_slots[i].pid = pid;
757 /* Connection closes come asyncronously, so we cannot stack this store */
758 if (smtp_accept_max_per_host)
759 smtp_slots[i].host_address = string_copy_malloc(sender_host_address);
763 DEBUG(D_any) debug_printf("%d SMTP accept process%s running\n",
764 smtp_accept_count, smtp_accept_count == 1 ? "" : "es");
767 /* Get here via goto in error cases */
771 /* Close the streams associated with the socket which will also close the
772 socket fds in this process. We can't do anything if fclose() fails, but
773 logging brings it to someone's attention. However, "connection reset by peer"
774 isn't really a problem, so skip that one. On Solaris, a dropped connection can
775 manifest itself as a broken pipe, so drop that one too. If the streams don't
776 exist, something went wrong while setting things up. Make sure the socket
777 descriptors are closed, in order to drop the connection. */
781 if (fclose(smtp_out) != 0 && errno != ECONNRESET && errno != EPIPE)
782 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_out) failed: %s",
786 else (void)close(accept_socket);
790 if (fclose(smtp_in) != 0 && errno != ECONNRESET && errno != EPIPE)
791 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_in) failed: %s",
795 else (void)close(dup_accept_socket);
797 /* Release any store used in this process, including the store used for holding
798 the incoming host address and an expanded active_hostname. */
801 interface_address = sender_host_name = sender_host_address = NULL;
802 store_reset(reset_point);
808 /*************************************************
809 * Check wildcard listen special cases *
810 *************************************************/
812 /* This function is used when binding and listening on lists of addresses and
813 ports. It tests for special cases of wildcard listening, when IPv4 and IPv6
814 sockets may interact in different ways in different operating systems. It is
815 passed an error number, the list of listening addresses, and the current
816 address. Two checks are available: for a previous wildcard IPv6 address, or for
817 a following wildcard IPv4 address, in both cases on the same port.
819 In practice, pairs of wildcard addresses should be adjacent in the address list
820 because they are sorted that way below.
824 addresses the list of addresses
825 ipa the current IP address
826 back if TRUE, check for previous wildcard IPv6 address
827 if FALSE, check for a following wildcard IPv4 address
829 Returns: TRUE or FALSE
833 check_special_case(int eno, ip_address_item *addresses, ip_address_item *ipa,
836 ip_address_item *ipa2;
838 /* For the "back" case, if the failure was "address in use" for a wildcard IPv4
839 address, seek a previous IPv6 wildcard address on the same port. As it is
840 previous, it must have been successfully bound and be listening. Flag it as a
841 "6 including 4" listener. */
845 if (eno != EADDRINUSE || ipa->address[0] != 0) return FALSE;
846 for (ipa2 = addresses; ipa2 != ipa; ipa2 = ipa2->next)
848 if (ipa2->address[1] == 0 && ipa2->port == ipa->port)
850 ipa2->v6_include_v4 = TRUE;
856 /* For the "forward" case, if the current address is a wildcard IPv6 address,
857 we seek a following wildcard IPv4 address on the same port. */
861 if (ipa->address[0] != ':' || ipa->address[1] != 0) return FALSE;
862 for (ipa2 = ipa->next; ipa2 != NULL; ipa2 = ipa2->next)
863 if (ipa2->address[0] == 0 && ipa->port == ipa2->port) return TRUE;
872 /*************************************************
873 * Handle terminating subprocesses *
874 *************************************************/
876 /* Handle the termination of child processes. Theoretically, this need be done
877 only when sigchld_seen is TRUE, but rumour has it that some systems lose
878 SIGCHLD signals at busy times, so to be on the safe side, this function is
879 called each time round. It shouldn't be too expensive.
886 handle_ending_processes(void)
891 while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
895 debug_printf("child %d ended: status=0x%x\n", (int)pid, status);
897 if (WIFEXITED(status))
898 debug_printf(" normal exit, %d\n", WEXITSTATUS(status));
899 else if (WIFSIGNALED(status))
900 debug_printf(" signal exit, signal %d%s\n", WTERMSIG(status),
901 WCOREDUMP(status) ? " (core dumped)" : "");
905 /* If it's a listening daemon for which we are keeping track of individual
906 subprocesses, deal with an accepting process that has terminated. */
911 for (i = 0; i < smtp_accept_max; i++)
912 if (smtp_slots[i].pid == pid)
914 if (smtp_slots[i].host_address)
915 store_free(smtp_slots[i].host_address);
916 smtp_slots[i] = empty_smtp_slot;
917 if (--smtp_accept_count < 0) smtp_accept_count = 0;
918 DEBUG(D_any) debug_printf("%d SMTP accept process%s now running\n",
919 smtp_accept_count, (smtp_accept_count == 1)? "" : "es");
922 if (i < smtp_accept_max) continue; /* Found an accepting process */
925 /* If it wasn't an accepting process, see if it was a queue-runner
926 process that we are tracking. */
928 if (queue_runner_slots)
929 for (unsigned i = 0; i < queue_runner_slot_count; i++)
931 runner_slot * r = queue_runner_slots + i;
934 r->pid = 0; /* free up the slot */
936 if (--queue_run_count < 0) queue_run_count = 0;
937 DEBUG(D_any) debug_printf("%d queue-runner process%s now running\n",
938 queue_run_count, queue_run_count == 1 ? "" : "es");
940 for (qrunner ** p = &qrunners, * q = qrunners; q; p = &q->next, q = *p)
941 if (q->name == r->queue_name)
943 if (q->interval) /* a periodic queue run */
945 else /* a one-time run */
946 *p = q->next; /* drop this qrunner */
957 set_pid_file_path(void)
959 if (override_pid_file_path)
960 pid_file_path = override_pid_file_path;
963 pid_file_path = string_sprintf("%s/exim-daemon.pid", spool_directory);
965 if (pid_file_path[0] != '/')
966 log_write(0, LOG_PANIC_DIE, "pid file path %s must be absolute\n", pid_file_path);
970 enum pid_op { PID_WRITE, PID_CHECK, PID_DELETE };
972 /* Do various pid file operations as safe as possible. Ideally we'd just
973 drop the privileges for creation of the pid file and not care at all about removal of
975 Returns: true on success, false + errno==EACCES otherwise
979 operate_on_pid_file(const enum pid_op operation, const pid_t pid)
981 char pid_line[sizeof(int) * 3 + 2];
982 const int pid_len = snprintf(pid_line, sizeof(pid_line), "%d\n", (int)pid);
983 BOOL lines_match = FALSE;
984 uschar * path, * base, * dir;
986 const int dir_flags = O_RDONLY | O_NONBLOCK;
987 const int base_flags = O_NOFOLLOW | O_NONBLOCK;
988 const mode_t base_mode = 0644;
990 int cwd_fd = -1, dir_fd = -1, base_fd = -1;
991 BOOL success = FALSE;
995 if (!f.running_in_test_harness && real_uid != root_uid && real_uid != exim_uid) goto cleanup;
996 if (pid_len < 2 || pid_len >= (int)sizeof(pid_line)) goto cleanup;
998 path = string_copy(pid_file_path);
999 if ((base = Ustrrchr(path, '/')) == NULL) /* should not happen, but who knows */
1000 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid file path \"%s\" does not contain a '/'", pid_file_path);
1002 dir = base != path ? path : US"/";
1005 if (!dir || !*dir || *dir != '/') goto cleanup;
1006 if (!base || !*base || Ustrchr(base, '/') != NULL) goto cleanup;
1008 cwd_fd = open(".", dir_flags);
1009 if (cwd_fd < 0 || fstat(cwd_fd, &sb) != 0 || !S_ISDIR(sb.st_mode)) goto cleanup;
1010 dir_fd = open(CS dir, dir_flags);
1011 if (dir_fd < 0 || fstat(dir_fd, &sb) != 0 || !S_ISDIR(sb.st_mode)) goto cleanup;
1013 /* emulate openat */
1014 if (fchdir(dir_fd) != 0) goto cleanup;
1015 base_fd = open(CS base, O_RDONLY | base_flags);
1016 if (fchdir(cwd_fd) != 0)
1017 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1021 char line[sizeof(pid_line)];
1024 if (fstat(base_fd, &sb) != 0 || !S_ISREG(sb.st_mode)) goto cleanup;
1025 if ((sb.st_mode & 07777) != base_mode || sb.st_nlink != 1) goto cleanup;
1026 if (sb.st_size < 2 || sb.st_size >= (off_t)sizeof(line)) goto cleanup;
1028 len = read(base_fd, line, sizeof(line));
1029 if (len != (ssize_t)sb.st_size) goto cleanup;
1032 if (strspn(line, "0123456789") != (size_t)len-1) goto cleanup;
1033 if (line[len-1] != '\n') goto cleanup;
1034 lines_match = len == pid_len && strcmp(line, pid_line) == 0;
1037 if (operation == PID_WRITE)
1044 /* emulate unlinkat */
1045 if (fchdir(dir_fd) != 0) goto cleanup;
1046 error = unlink(CS base);
1047 if (fchdir(cwd_fd) != 0)
1048 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1049 if (error) goto cleanup;
1050 (void)close(base_fd);
1053 /* emulate openat */
1054 if (fchdir(dir_fd) != 0) goto cleanup;
1055 base_fd = open(CS base, O_WRONLY | O_CREAT | O_EXCL | base_flags, base_mode);
1056 if (fchdir(cwd_fd) != 0)
1057 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1058 if (base_fd < 0) goto cleanup;
1059 if (fchmod(base_fd, base_mode) != 0) goto cleanup;
1060 if (write(base_fd, pid_line, pid_len) != pid_len) goto cleanup;
1061 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1066 if (!lines_match) goto cleanup;
1067 if (operation == PID_DELETE)
1070 /* emulate unlinkat */
1071 if (fchdir(dir_fd) != 0) goto cleanup;
1072 error = unlink(CS base);
1073 if (fchdir(cwd_fd) != 0)
1074 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1075 if (error) goto cleanup;
1083 if (cwd_fd >= 0) (void)close(cwd_fd);
1084 if (dir_fd >= 0) (void)close(dir_fd);
1085 if (base_fd >= 0) (void)close(base_fd);
1090 /* Remove the daemon's pidfile. Note: runs with root privilege,
1091 as a direct child of the daemon. Does not return. */
1094 delete_pid_file(void)
1096 const BOOL success = operate_on_pid_file(PID_DELETE, getppid());
1099 debug_printf("delete pid file %s %s: %s\n", pid_file_path,
1100 success ? "success" : "failure", strerror(errno));
1102 exim_exit(EXIT_SUCCESS);
1106 /* Called by the daemon; exec a child to get the pid file deleted
1107 since we may require privs for the containing directory */
1114 DEBUG(D_any) debug_printf("SIGTERM/SIGINT seen\n");
1115 #if !defined(DISABLE_TLS) && (defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT))
1116 tls_watch_invalidate();
1119 if (daemon_notifier_fd >= 0)
1121 close(daemon_notifier_fd);
1122 daemon_notifier_fd = -1;
1123 unlink_notifier_socket();
1126 if (f.running_in_test_harness || write_pid)
1128 if ((pid = exim_fork(US"daemon-del-pidfile")) == 0)
1130 if (override_pid_file_path)
1131 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 3,
1132 "-oP", override_pid_file_path, "-oPX");
1134 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 1, "-oPX");
1136 /* Control never returns here. */
1139 child_close(pid, 1);
1141 exim_exit(EXIT_SUCCESS);
1145 /*************************************************
1146 * Listener socket for local work prompts *
1147 *************************************************/
1150 daemon_client_sockname(struct sockaddr_un * sup, uschar ** sname)
1152 #ifdef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1153 sup->sun_path[0] = 0; /* Abstract local socket addr - Linux-specific? */
1154 return offsetof(struct sockaddr_un, sun_path) + 1
1155 + snprintf(sup->sun_path+1, sizeof(sup->sun_path)-1, "exim_%d", getpid());
1157 *sname = string_sprintf("%s/p_%d", spool_directory, getpid());
1158 return offsetof(struct sockaddr_un, sun_path)
1159 + snprintf(sup->sun_path, sizeof(sup->sun_path), "%s", CS *sname);
1164 daemon_notifier_sockname(struct sockaddr_un * sup)
1166 #ifdef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1167 sup->sun_path[0] = 0; /* Abstract local socket addr - Linux-specific? */
1168 return offsetof(struct sockaddr_un, sun_path) + 1
1169 + snprintf(sup->sun_path+1, sizeof(sup->sun_path)-1, "%s",
1170 CS expand_string(notifier_socket));
1172 notifier_socket_name = expand_string(notifier_socket);
1173 return offsetof(struct sockaddr_un, sun_path)
1174 + snprintf(sup->sun_path, sizeof(sup->sun_path), "%s",
1175 CS notifier_socket_name);
1181 daemon_notifier_socket(void)
1184 const uschar * where;
1185 struct sockaddr_un sa_un = {.sun_family = AF_UNIX};
1188 if (!f.notifier_socket_en)
1190 DEBUG(D_any) debug_printf("-oY used so not creating notifier socket\n");
1193 if (override_local_interfaces && !override_pid_file_path)
1196 debug_printf("-oX used without -oP so not creating notifier socket\n");
1199 if (!notifier_socket || !*notifier_socket)
1201 DEBUG(D_any) debug_printf("no name for notifier socket\n");
1205 DEBUG(D_any) debug_printf("creating notifier socket\n");
1208 if ((fd = socket(PF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0)
1209 { where = US"socket"; goto bad; }
1211 if ((fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0)
1212 { where = US"socket"; goto bad; }
1213 (void)fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
1216 len = daemon_notifier_sockname(&sa_un);
1218 #ifdef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1219 DEBUG(D_any) debug_printf(" @%s\n", sa_un.sun_path+1);
1220 #else /* filesystem-visible and persistent; will neeed removal */
1221 DEBUG(D_any) debug_printf(" %s\n", sa_un.sun_path);
1224 if (bind(fd, (const struct sockaddr *)&sa_un, (socklen_t)len) < 0)
1225 { where = US"bind"; goto bad; }
1227 #ifdef SO_PASSCRED /* Linux */
1228 if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0)
1229 { where = US"SO_PASSCRED"; goto bad2; }
1230 #elif defined(LOCAL_CREDS) /* FreeBSD-ish */
1231 if (setsockopt(fd, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
1232 { where = US"LOCAL_CREDS"; goto bad2; }
1235 /* debug_printf("%s: fd %d\n", __FUNCTION__, fd); */
1236 daemon_notifier_fd = fd;
1240 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1241 Uunlink(sa_un.sun_path);
1244 log_write(0, LOG_MAIN|LOG_PANIC, "%s %s: %s",
1245 __FUNCTION__, where, strerror(errno));
1251 /* Data for notifier-triggered queue runs */
1253 static uschar queuerun_msgid[MESSAGE_ID_LENGTH+1];
1254 static const uschar * queuerun_msg_qname;
1257 /* The notifier socket has something to read. Pull the message from it, decode
1260 Return TRUE if a sigalrm should be emulated */
1263 daemon_notification(void)
1265 uschar buf[256], cbuf[256];
1266 struct sockaddr_un sa_un;
1267 struct iovec iov = {.iov_base = buf, .iov_len = sizeof(buf)-1};
1268 struct msghdr msg = { .msg_name = &sa_un,
1269 .msg_namelen = sizeof(sa_un),
1272 .msg_control = cbuf,
1273 .msg_controllen = sizeof(cbuf)
1277 buf[sizeof(buf)-1] = 0;
1278 if ((sz = recvmsg(daemon_notifier_fd, &msg, 0)) <= 0) return FALSE;
1279 if (sz >= sizeof(buf)) return FALSE;
1282 debug_printf("addrlen %d\n", msg.msg_namelen);
1285 if (msg.msg_namelen > 0)
1287 BOOL abstract = !*sa_un.sun_path;
1288 char * name = sa_un.sun_path + (abstract ? 1 : 0);
1289 int namelen = (int)msg.msg_namelen - abstract ? 1 : 0;
1291 debug_printf("%s from addr '%s%.*s'\n", __FUNCTION__,
1292 abstract ? "@" : "",
1295 debug_printf("%s (from unknown addr)\n", __FUNCTION__);
1298 debug_printf("%s (from unknown addr)\n", __FUNCTION__);
1300 /* Refuse to handle the item unless the peer has good credentials */
1301 #ifdef SCM_CREDENTIALS
1302 # define EXIM_SCM_CR_TYPE SCM_CREDENTIALS
1303 #elif defined(LOCAL_CREDS) && defined(SCM_CREDS)
1304 # define EXIM_SCM_CR_TYPE SCM_CREDS
1306 /* The OS has no way to get the creds of the caller (for a unix/datagram socket.
1307 Punt; don't try to check. */
1310 #ifdef EXIM_SCM_CR_TYPE
1311 for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg);
1313 cp = CMSG_NXTHDR(&msg, cp))
1314 if (cp->cmsg_level == SOL_SOCKET && cp->cmsg_type == EXIM_SCM_CR_TYPE)
1316 # ifdef SCM_CREDENTIALS /* Linux */
1317 struct ucred * cr = (struct ucred *) CMSG_DATA(cp);
1318 if (cr->uid && cr->uid != exim_uid)
1320 DEBUG(D_queue_run) debug_printf("%s: sender creds pid %d uid %d gid %d\n",
1321 __FUNCTION__, (int)cr->pid, (int)cr->uid, (int)cr->gid);
1323 # elif defined(LOCAL_CREDS) /* BSD-ish */
1324 struct sockcred * cr = (struct sockcred *) CMSG_DATA(cp);
1325 if (cr->sc_uid && cr->sc_uid != exim_uid)
1327 DEBUG(D_queue_run) debug_printf("%s: sender creds pid ??? uid %d gid %d\n",
1328 __FUNCTION__, (int)cr->sc_uid, (int)cr->sc_gid);
1338 #ifndef DISABLE_QUEUE_RAMP
1339 case NOTIFY_MSG_QRUN:
1340 /* this should be a message_id */
1342 debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1);
1344 memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1);
1346 for (qrunner * q = qrunners; q; q = q->next)
1348 ? Ustrcmp(q->name, buf+1+MESSAGE_ID_LENGTH+1) == 0
1349 : !buf[1+MESSAGE_ID_LENGTH+1]
1351 { queuerun_msg_qname = q->name; break; }
1355 case NOTIFY_QUEUE_SIZE_REQ:
1358 int len = snprintf(CS buf, sizeof(buf), "%u", queue_count_cached());
1361 debug_printf("%s: queue size request: %s\n", __FUNCTION__, buf);
1363 if (sendto(daemon_notifier_fd, buf, len, 0,
1364 (const struct sockaddr *)&sa_un, msg.msg_namelen) < 0)
1365 log_write(0, LOG_MAIN|LOG_PANIC,
1366 "%s: sendto: %s\n", __FUNCTION__, strerror(errno));
1371 regex_at_daemon(buf);
1380 daemon_inetd_wtimeout(time_t last_connection_time)
1382 time_t resignal_interval = inetd_wait_timeout;
1384 if (last_connection_time == (time_t)0)
1387 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
1391 time_t now = time(NULL);
1392 if (now == (time_t)-1)
1394 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
1396 else if ((now - last_connection_time) >= inetd_wait_timeout)
1399 debug_printf("inetd wait timeout %d expired, ending daemon\n",
1400 inetd_wait_timeout);
1401 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
1403 daemon_die(); /* Does not return */
1406 resignal_interval -= (now - last_connection_time);
1409 sigalrm_seen = FALSE;
1410 ALARM(resignal_interval);
1414 /* Re-sort the qrunners list, and return the shortest interval.
1415 That could be negatime.
1416 The next-tick times should have been updated by any runs initiated,
1417 though will not be when the global limit on runners was reached.
1419 Unlikely to have many queues, so insertion-sort.
1423 next_qrunner_interval(void)
1425 qrunner * sorted = NULL;
1426 for (qrunner * q = qrunners, * next; q; q = next)
1432 qrunner ** p = &sorted;
1433 for (qrunner * qq; qq = *p; p = &(qq->next))
1434 if ( q->next_tick < qq->next_tick
1435 || q->next_tick == qq->next_tick && q->interval < qq->interval
1449 return qrunners ? qrunners->next_tick - time(NULL) : 0;
1453 daemon_qrun(int local_queue_run_max, struct pollfd * fd_polls, int listen_socket_count)
1455 DEBUG(D_any) debug_printf("%s received\n",
1456 #ifndef DISABLE_QUEUE_RAMP
1457 *queuerun_msgid ? "qrun notification" :
1461 /* Do a full queue run in a child process, if required, unless we already have
1462 enough queue runners on the go. If we are not running as root, a re-exec is
1463 required. In the calling process, restart the alamr timer for the next run. */
1465 if (is_multiple_qrun())
1466 if (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max)
1470 #ifndef DISABLE_QUEUE_RAMP
1471 if (*queuerun_msgid) /* See if we can start another runner for this queue */
1473 for (qrunner * qq = qrunners; qq; qq = qq->next)
1474 if (qq->name == queuerun_msg_qname)
1476 q = qq->run_count < qq->run_max ? qq : NULL;
1482 /* In order of run priority, find the first queue for which we can start
1485 for (q = qrunners; q; q = q->next)
1486 if (q->run_count < q->run_max) break;
1492 /* Bump this queue's next-tick by it's interval */
1496 time_t now = time(NULL);
1497 do ; while ((q->next_tick += q->interval) <= now);
1500 if ((pid = exim_fork(US"queue-runner")) == 0)
1502 /* Disable debugging if it's required only for the daemon process. We
1503 leave the above message, because it ties up with the "child ended"
1504 debugging messages. */
1506 if (f.debug_daemon) debug_selector = 0;
1508 /* Close any open listening sockets in the child */
1510 close_daemon_sockets(daemon_notifier_fd,
1511 fd_polls, listen_socket_count);
1513 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
1515 signal(SIGHUP, SIG_DFL);
1516 signal(SIGCHLD, SIG_DFL);
1517 signal(SIGTERM, SIG_DFL);
1518 signal(SIGINT, SIG_DFL);
1520 /* Re-exec if privilege has been given up, unless deliver_drop_
1521 privilege is set. Reset SIGALRM before exec(). */
1523 if (geteuid() != root_uid && !deliver_drop_privilege)
1530 signal(SIGALRM, SIG_DFL);
1535 if ( q->queue_2stage
1536 #ifndef DISABLE_QUEUE_RAMP
1540 if (q->queue_run_first_delivery) *p++ = 'i';
1541 if (q->queue_run_force) *p++ = 'f';
1542 if (q->deliver_force_thaw) *p++ = 'f';
1543 if (q->queue_run_local) *p++ = 'l';
1547 ? string_sprintf("%sG%s", opt, q->name) : opt;
1549 #ifndef DISABLE_QUEUE_RAMP
1550 if (*queuerun_msgid)
1552 log_write(0, LOG_MAIN, "notify triggered queue run");
1553 extra[extracount++] = queuerun_msgid; /* Trigger only the */
1554 extra[extracount++] = queuerun_msgid; /* one message */
1558 /* If -R or -S were on the original command line, ensure they get
1561 if (deliver_selectstring)
1563 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
1564 extra[extracount++] = deliver_selectstring;
1567 if (deliver_selectstring_sender)
1569 extra[extracount++] = f.deliver_selectstring_sender_regex
1571 extra[extracount++] = deliver_selectstring_sender;
1574 /* Overlay this process with a new execution. */
1576 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
1577 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
1579 /* Control never returns here. */
1582 /* No need to re-exec; SIGALRM remains set to the default handler */
1584 #ifndef DISABLE_QUEUE_RAMP
1585 if (*queuerun_msgid)
1587 log_write(0, LOG_MAIN, "notify triggered queue run");
1588 f.queue_2stage = FALSE;
1589 queue_run(q, queuerun_msgid, queuerun_msgid, FALSE);
1593 queue_run(q, NULL, NULL, FALSE);
1594 exim_underbar_exit(EXIT_SUCCESS);
1599 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
1600 "process failed: %s", strerror(errno));
1605 for (int i = 0; i < local_queue_run_max; ++i)
1606 if (queue_runner_slots[i].pid <= 0)
1608 queue_runner_slots[i].pid = pid;
1609 queue_runner_slots[i].queue_name = q->name;
1614 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
1615 queue_run_count, queue_run_count == 1 ? "" : "es");
1620 sigalrm_seen = FALSE;
1621 #ifndef DISABLE_QUEUE_RAMP
1622 if (*queuerun_msgid) /* it was a fast-ramp kick */
1623 *queuerun_msgid = 0;
1624 else /* periodic or one-time queue run */
1626 { /* Impose a minimum 1s tick, even when a run was outstanding */
1627 int interval = next_qrunner_interval();
1628 if (interval <= 0) interval = 1;
1630 if (qrunners) /* there are still periodic qrunners */
1643 describe_queue_runners(void)
1647 if (!is_multiple_qrun()) return US"no queue runs";
1649 for (qrunner * q = qrunners; q; q = q->next)
1651 g = string_catn(g, US"-q", 2);
1652 if (q->name) g = string_append(g, 3, US"G", q->name, US"/");
1653 g = string_cat(g, readconf_printtime(q->interval));
1654 g = string_catn(g, US" ", 1);
1657 gstring_release_unused(g);
1658 return string_from_gstring(g);
1662 /*************************************************
1663 * Exim Daemon Mainline *
1664 *************************************************/
1666 /* The daemon can do two jobs, either of which is optional:
1668 (1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1669 each one. This is requested by the -bd option, with -oX specifying the SMTP
1670 port on which to listen (for testing).
1672 (2) Spawns a queue-running process every so often. This is controlled by the
1673 -q option with a an interval time. (If no time is given, a single queue run
1674 is done from the main function, and control doesn't get here.)
1676 Root privilege is required in order to attach to port 25. Some systems require
1677 it when calling socket() rather than bind(). To cope with all cases, we run as
1678 root for both socket() and bind(). Some systems also require root in order to
1679 write to the pid file directory. This function must therefore be called as root
1680 if it is to work properly in all circumstances. Once the socket is bound and
1681 the pid file written, root privilege is given up if there is an exim uid.
1683 There are no arguments to this function, and it never returns. */
1689 struct pollfd * fd_polls, * tls_watch_poll = NULL, * dnotify_poll = NULL;
1690 int listen_socket_count = 0, poll_fd_count;
1691 ip_address_item * addresses = NULL;
1692 time_t last_connection_time = (time_t)0;
1693 int local_queue_run_max = 0;
1695 if (is_multiple_qrun())
1697 /* Nuber of runner-tracking structs needed: If the option queue_run_max has
1698 no expandable elements then it is the overall maximum; else we assume it
1699 depends on the queue name, and add them up to get the maximum.
1700 Evaluate both that and the individual limits. */
1702 if (Ustrchr(queue_run_max, '$') != NULL)
1704 for (qrunner * q = qrunners; q; q = q->next)
1706 queue_name = q->name;
1707 local_queue_run_max +=
1708 (q->run_max = atoi(CS expand_string(queue_run_max)));
1714 local_queue_run_max = atoi(CS expand_string(queue_run_max));
1715 for (qrunner * q = qrunners; q; q = q->next)
1716 q->run_max = local_queue_run_max;
1719 process_purpose = US"daemon";
1721 /* If any debugging options are set, turn on the D_pid bit so that all
1722 debugging lines get the pid added. */
1724 DEBUG(D_any|D_v) debug_selector |= D_pid;
1726 /* Allocate enough pollstructs for inetd mode plus the ancillary sockets;
1727 also used when there are no listen sockets. */
1729 fd_polls = store_get(sizeof(struct pollfd) * 3, GET_UNTAINTED);
1731 if (f.inetd_wait_mode)
1733 listen_socket_count = 1;
1735 if (dup2(0, 3) == -1)
1736 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1737 "failed to dup inetd socket safely away: %s", strerror(errno));
1740 fd_polls[0].events = POLLIN;
1746 if (debug_file == stderr)
1748 /* need a call to log_write before call to open debug_file, so that
1749 log.c:file_path has been initialised. This is unfortunate. */
1750 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1754 exim_nullstd(); /* re-open fd2 after we just closed it again */
1755 debug_logging_activate(US"-wait", NULL);
1758 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1760 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1761 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1764 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1765 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1770 if (f.inetd_wait_mode || f.daemon_listen)
1772 /* If any option requiring a load average to be available during the
1773 reception of a message is set, call os_getloadavg() while we are root
1774 for those OS for which this is necessary the first time it is called (in
1775 order to perform an "open" on the kernel memory file). */
1777 #ifdef LOAD_AVG_NEEDS_ROOT
1778 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1779 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1780 (void)os_getloadavg();
1785 /* Do the preparation for setting up a listener on one or more interfaces, and
1786 possible on various ports. This is controlled by the combination of
1787 local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1788 (which is a list of default ports to use for those items in local_interfaces
1789 that do not specify a port). The -oX command line option can be used to
1790 override one or both of these options.
1792 If local_interfaces is not set, the default is to listen on all interfaces.
1793 When it is set, it can include "all IPvx interfaces" as an item. This is useful
1794 when different ports are in use.
1796 It turns out that listening on all interfaces is messy in an IPv6 world,
1797 because several different implementation approaches have been taken. This code
1798 is now supposed to work with all of them. The point of difference is whether an
1799 IPv6 socket that is listening on all interfaces will receive incoming IPv4
1800 calls or not. We also have to cope with the case when IPv6 libraries exist, but
1801 there is no IPv6 support in the kernel.
1803 . On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1804 addresses. However, if an IPv4 socket is also listening on all interfaces,
1805 calls are directed to the appropriate socket.
1807 . On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1808 give them as mapped addresses, but an attempt also to listen on an IPv4
1809 socket on all interfaces causes an error.
1811 . On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1812 two sockets if you want to accept both kinds of call.
1814 . FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1815 can be turned off, to make it behave like the versions of Linux described
1818 . I heard a report that the USAGI IPv6 stack for Linux has implemented
1821 So, what we do when IPv6 is supported is as follows:
1823 (1) After it is set up, the list of interfaces is scanned for wildcard
1824 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1825 port, the list is re-arranged so that they are together, with the IPv6
1828 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1829 carry on if an IPv4 wildcard socket for the same port follows later in the
1830 list. This allows Exim to carry on in the case when the kernel has no IPv6
1833 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1834 option is defined. However, if setting fails, carry on regardless (but log
1837 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1840 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1841 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1842 port (which must have succeeded or we wouldn't have got this far), we
1843 assume we are in the situation where just a single socket is permitted,
1844 and ignore the error.
1848 The preparation code decodes options and sets up the relevant data. We do this
1849 first, so that we can return non-zero if there are any syntax errors, and also
1852 if (f.daemon_listen && !f.inetd_wait_mode)
1854 int *default_smtp_port;
1858 const uschar * list;
1859 uschar *local_iface_source = US"local_interfaces";
1860 ip_address_item *ipa;
1861 ip_address_item **pipa;
1863 /* If -oX was used, disable the writing of a pid file unless -oP was
1864 explicitly used to force it. Then scan the string given to -oX. Any items
1865 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1866 Any other items are used to override local_interfaces. */
1868 if (override_local_interfaces)
1870 gstring * new_smtp_port = NULL;
1871 gstring * new_local_interfaces = NULL;
1873 if (!override_pid_file_path) write_pid = FALSE;
1875 list = override_local_interfaces;
1877 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
1880 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
1886 *gp = string_catn(*gp, US"<", 1);
1889 *gp = string_catn(*gp, joinstr, 2);
1890 *gp = string_cat (*gp, s);
1895 daemon_smtp_port = string_from_gstring(new_smtp_port);
1896 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1900 if (new_local_interfaces)
1902 local_interfaces = string_from_gstring(new_local_interfaces);
1903 local_iface_source = US"-oX data";
1904 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1909 /* Create a list of default SMTP ports, to be used if local_interfaces
1910 contains entries without explicit ports. First count the number of ports, then
1911 build a translated list in a vector. */
1913 list = daemon_smtp_port;
1915 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
1917 default_smtp_port = store_get((pct+1) * sizeof(int), GET_UNTAINTED);
1918 list = daemon_smtp_port;
1921 (s = string_nextinlist(&list, &sep, NULL, 0));
1927 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1928 if (end != s + Ustrlen(s))
1929 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1933 struct servent *smtp_service = getservbyname(CS s, "tcp");
1935 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1936 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1939 default_smtp_port[pct] = 0;
1941 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1943 list = tls_in.on_connect_ports;
1945 /* the list isn't expanded so cannot be tainted. If it ever is we will trap here */
1946 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1951 list = tls_in.on_connect_ports;
1952 tls_in.on_connect_ports = NULL;
1954 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1958 struct servent * smtp_service = getservbyname(CS s, "tcp");
1960 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1961 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
1963 g = string_append_listele(g, ':', s);
1966 tls_in.on_connect_ports = g->s;
1970 /* Create the list of local interfaces, possibly with ports included. This
1971 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1972 values are converted below. */
1974 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1976 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1977 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1978 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1979 anyway, but we need to know which are the wildcard addresses, and the shorter
1982 In the same scan, fill in missing port numbers from the default list. When
1983 there is more than one item in the list, extra items are created. */
1985 for (ipa = addresses; ipa; ipa = ipa->next)
1987 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1988 ipa->address[0] = 0;
1989 else if (Ustrcmp(ipa->address, "::0") == 0)
1991 ipa->address[0] = ':';
1992 ipa->address[1] = 0;
1995 if (ipa->port > 0) continue;
1997 if (daemon_smtp_port[0] <= 0)
1998 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1999 "%s and daemon_smtp_port is unset; cannot start daemon",
2000 ipa->address[0] == 0 ? US"\"all IPv4\"" :
2001 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
2003 ipa->port = default_smtp_port[0];
2004 for (int i = 1; default_smtp_port[i] > 0; i++)
2006 ip_address_item * new = store_get(sizeof(ip_address_item), GET_UNTAINTED);
2008 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
2009 new->port = default_smtp_port[i];
2010 new->next = ipa->next;
2016 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
2017 wildcard for the same port, ensure that (a) they are together and (b) the
2018 IPv6 address comes first. This makes handling the messy features easier, and
2019 also simplifies the construction of the "daemon started" log line. */
2022 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
2024 ip_address_item *ipa2;
2026 /* Handle an IPv4 wildcard */
2028 if (ipa->address[0] == 0)
2029 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
2031 ip_address_item *ipa3 = ipa2->next;
2032 if (ipa3->address[0] == ':' &&
2033 ipa3->address[1] == 0 &&
2034 ipa3->port == ipa->port)
2036 ipa2->next = ipa3->next;
2043 /* Handle an IPv6 wildcard. */
2045 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
2046 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
2048 ip_address_item *ipa3 = ipa2->next;
2049 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
2051 ipa2->next = ipa3->next;
2052 ipa3->next = ipa->next;
2060 /* Get a vector to remember all the sockets in.
2061 Two extra elements for the ancillary sockets */
2063 for (ipa = addresses; ipa; ipa = ipa->next)
2064 listen_socket_count++;
2065 fd_polls = store_get(sizeof(struct pollfd) * (listen_socket_count + 2),
2067 for (struct pollfd * p = fd_polls; p < fd_polls + listen_socket_count + 2;
2069 { p->fd = -1; p->events = POLLIN; }
2071 } /* daemon_listen but not inetd_wait_mode */
2073 if (f.daemon_listen)
2076 /* Do a sanity check on the max connects value just to save us from getting
2077 a huge amount of store. */
2079 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
2081 /* There's no point setting smtp_accept_queue unless it is less than the max
2082 connects limit. The configuration reader ensures that the max is set if the
2083 queue-only option is set. */
2085 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
2087 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
2088 track of them for total number and queue/host limits. */
2090 if (smtp_accept_max > 0)
2092 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), GET_UNTAINTED);
2093 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
2097 /* The variable background_daemon is always false when debugging, but
2098 can also be forced false in order to keep a non-debugging daemon in the
2099 foreground. If background_daemon is true, close all open file descriptors that
2100 we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
2101 do this for inetd_wait mode.
2103 This is protection against any called functions (in libraries, or in
2104 Perl, or whatever) that think they can write to stderr (or stdout). Before this
2105 was added, it was quite likely that an SMTP connection would use one of these
2106 file descriptors, in which case writing random stuff to it caused chaos.
2108 Then disconnect from the controlling terminal, Most modern Unixes seem to have
2109 setsid() for getting rid of the controlling terminal. For any OS that doesn't,
2110 setsid() can be #defined as a no-op, or as something else. */
2112 if (f.background_daemon || f.inetd_wait_mode)
2114 log_close_all(); /* Just in case anything was logged earlier */
2115 search_tidyup(); /* Just in case any were used in reading the config. */
2116 (void)close(0); /* Get rid of stdin/stdout/stderr */
2119 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
2120 log_stderr = NULL; /* So no attempt to copy paniclog output */
2123 if (f.background_daemon)
2125 /* If the parent process of this one has pid == 1, we are re-initializing the
2126 daemon as the result of a SIGHUP. In this case, there is no need to do
2127 anything, because the controlling terminal has long gone. Otherwise, fork, in
2128 case current process is a process group leader (see 'man setsid' for an
2129 explanation) before calling setsid().
2130 All other forks want daemon_listen cleared. Rather than blow a register, jsut
2135 BOOL daemon_listen = f.daemon_listen;
2136 pid_t pid = exim_fork(US"daemon");
2137 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2138 "fork() failed when starting daemon: %s", strerror(errno));
2139 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
2140 (void)setsid(); /* release controlling terminal */
2141 f.daemon_listen = daemon_listen;
2145 /* We are now in the disconnected, daemon process (unless debugging). Set up
2146 the listening sockets if required. */
2148 daemon_notifier_socket();
2150 if (f.daemon_listen && !f.inetd_wait_mode)
2153 ip_address_item *ipa;
2155 /* For each IP address, create a socket, bind it to the appropriate port, and
2156 start listening. See comments above about IPv6 sockets that may or may not
2157 accept IPv4 calls when listening on all interfaces. We also have to cope with
2158 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
2159 listening, provided a wildcard IPv4 socket for the same port follows. */
2161 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
2164 ip_address_item * ipa2;
2167 if (Ustrchr(ipa->address, ':') != NULL)
2170 wildcard = ipa->address[1] == 0;
2175 wildcard = ipa->address[0] == 0;
2178 if ((fd_polls[sk].fd = fd = ip_socket(SOCK_STREAM, af)) < 0)
2180 if (check_special_case(0, addresses, ipa, FALSE))
2182 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
2183 "listening (%s): will use IPv4", strerror(errno));
2186 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
2187 af == AF_INET6 ? '6' : '4', strerror(errno));
2190 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
2191 available. Just log failure (can get protocol not available, just like
2192 socket creation can). */
2195 if (af == AF_INET6 && wildcard &&
2196 setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2197 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
2198 "socket failed (%s): carrying on without it", strerror(errno));
2199 #endif /* IPV6_V6ONLY */
2201 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
2202 is being handled. Without this, a connection will prevent reuse of the
2203 smtp port for listening. */
2205 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0)
2206 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
2207 "failed when starting daemon: %s", strerror(errno));
2209 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
2210 disable this because it breaks some broken clients. */
2212 if (tcp_nodelay) setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on));
2214 /* Now bind the socket to the required port; if Exim is being restarted
2215 it may not always be possible to bind immediately, even with SO_REUSEADDR
2216 set, so try 10 times, waiting between each try. After 10 failures, we give
2217 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
2218 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
2219 address for the same port, ignore the error on the grounds that we must be
2220 in a system where the IPv6 socket accepts both kinds of call. This is
2221 necessary for (some release of) USAGI Linux; other IP stacks fail at the
2222 listen() stage instead. */
2225 f.tcp_fastopen_ok = TRUE;
2230 if (ip_bind(fd, af, ipa->address, ipa->port) >= 0) break;
2231 if (check_special_case(errno, addresses, ipa, TRUE))
2233 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
2234 "listen() success; EADDRINUSE ignored\n");
2238 msg = US strerror(errno);
2244 if (daemon_startup_retries <= 0)
2245 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2246 "socket bind() to port %d for address %s failed: %s: "
2247 "daemon abandoned", ipa->port, addr, msg);
2248 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
2249 "failed: %s: waiting %s before trying again (%d more %s)",
2250 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
2251 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
2252 daemon_startup_retries--;
2253 sleep(daemon_startup_sleep);
2258 debug_printf("listening on all interfaces (IPv%c) port %d\n",
2259 af == AF_INET6 ? '6' : '4', ipa->port);
2261 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
2263 /* Start listening on the bound socket, establishing the maximum backlog of
2264 connections that is allowed. On success, add to the set of sockets for select
2265 and continue to the next address. */
2267 #if defined(TCP_FASTOPEN) && !defined(__APPLE__)
2268 if ( f.tcp_fastopen_ok
2269 && setsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN,
2270 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
2272 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
2273 f.tcp_fastopen_ok = FALSE;
2276 if (listen(fd, smtp_connect_backlog) >= 0)
2278 #if defined(TCP_FASTOPEN) && defined(__APPLE__)
2279 if ( f.tcp_fastopen_ok
2280 && setsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN, &on, sizeof(on)))
2282 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
2283 f.tcp_fastopen_ok = FALSE;
2286 fd_polls[sk].fd = fd;
2290 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
2291 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
2292 and there was a previous successful IPv6 wildcard listen on the same port,
2293 we want to ignore the error on the grounds that we must be in a system
2294 where the IPv6 socket accepts both kinds of call. */
2296 if (!check_special_case(errno, addresses, ipa, TRUE))
2297 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
2299 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
2302 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
2303 "listen() success; EADDRINUSE ignored\n");
2306 /* Come here if there has been a problem with the socket which we
2307 are going to ignore. We remove the address from the chain, and back up the
2311 sk--; /* Back up the count */
2312 listen_socket_count--; /* Reduce the total */
2313 if (ipa == addresses) addresses = ipa->next; else
2315 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
2316 ipa2->next = ipa->next;
2319 } /* End of bind/listen loop for each address */
2320 } /* End of setup for listening */
2323 /* If we are not listening, we want to write a pid file only if -oP was
2324 explicitly given. */
2326 else if (!override_pid_file_path)
2329 /* Write the pid to a known file for assistance in identification, if required.
2330 We do this before giving up root privilege, because on some systems it is
2331 necessary to be root in order to write into the pid file directory. There's
2332 nothing to stop multiple daemons running, as long as no more than one listens
2333 on a given TCP/IP port on the same interface(s). However, in these
2334 circumstances it gets far too complicated to mess with pid file names
2335 automatically. Consequently, Exim 4 writes a pid file only
2337 (a) When running in the test harness, or
2338 (b) When -bd is used and -oX is not used, or
2339 (c) When -oP is used to supply a path.
2341 The variable daemon_write_pid is used to control this. */
2343 if (f.running_in_test_harness || write_pid)
2345 const enum pid_op operation = (f.running_in_test_harness
2346 || real_uid == root_uid
2347 || (real_uid == exim_uid && !override_pid_file_path)) ? PID_WRITE : PID_CHECK;
2348 if (!operate_on_pid_file(operation, getpid()))
2349 DEBUG(D_any) debug_printf("%s pid file %s: %s\n", (operation == PID_WRITE) ? "write" : "check", pid_file_path, strerror(errno));
2352 /* Set up the handler for SIGHUP, which causes a restart of the daemon. */
2354 sighup_seen = FALSE;
2355 signal(SIGHUP, sighup_handler);
2357 /* Give up root privilege at this point (assuming that exim_uid and exim_gid
2358 are not root). The third argument controls the running of initgroups().
2359 Normally we do this, in order to set up the groups for the Exim user. However,
2360 if we are not root at this time - some odd installations run that way - we
2363 exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
2365 /* Update the originator_xxx fields so that received messages as listed as
2366 coming from Exim, not whoever started the daemon. */
2368 originator_uid = exim_uid;
2369 originator_gid = exim_gid;
2370 originator_login = (pw = getpwuid(exim_uid))
2371 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
2373 /* Get somewhere to keep the list of queue-runner pids if we are keeping track
2374 of them (and also if we are doing queue runs). */
2376 if (is_multiple_qrun() && local_queue_run_max > 0)
2378 queue_runner_slot_count = local_queue_run_max;
2379 queue_runner_slots = store_get(local_queue_run_max * sizeof(runner_slot), GET_UNTAINTED);
2380 memset(queue_runner_slots, 0, local_queue_run_max * sizeof(runner_slot));
2383 /* Set up the handler for termination of child processes, and the one
2384 telling us to die. */
2386 sigchld_seen = FALSE;
2387 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
2389 sigterm_seen = FALSE;
2390 os_non_restarting_signal(SIGTERM, main_sigterm_handler);
2391 os_non_restarting_signal(SIGINT, main_sigterm_handler);
2393 /* If we are to run the queue periodically, pretend the alarm has just gone
2394 off. This will cause the first queue-runner to get kicked off straight away.
2395 Get an initial sort of the list of queues, to prioritize the initial q-runs */
2398 if ((sigalrm_seen = is_multiple_qrun()))
2399 (void) next_qrunner_interval();
2401 /* Log the start up of a daemon - at least one of listening or queue running
2404 if (f.inetd_wait_mode)
2406 uschar *p = big_buffer;
2408 if (inetd_wait_timeout >= 0)
2409 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
2411 sprintf(CS p, "with no wait timeout");
2413 log_write(0, LOG_MAIN,
2414 "exim %s daemon started: pid=%d, launched with listening socket, %s",
2415 version_string, getpid(), big_buffer);
2416 set_process_info("daemon(%s): pre-listening socket", version_string);
2418 /* set up the timeout logic */
2419 sigalrm_seen = TRUE;
2422 else if (f.daemon_listen)
2425 int smtps_ports = 0;
2426 ip_address_item * ipa;
2428 const uschar * qinfo = describe_queue_runners();
2430 /* Build a list of listening addresses in big_buffer, but limit it to 10
2431 items. The style is for backwards compatibility.
2433 It is possible to have some ports listening for SMTPS (as opposed to TLS
2434 startted by STARTTLS), and others listening for standard SMTP. Keep their
2435 listings separate. */
2437 for (int j = 0, i; j < 2; j++)
2438 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
2440 /* First time round, look for SMTP ports; second time round, look for
2441 SMTPS ports. Build IP+port strings. */
2443 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
2450 /* Now the information about the port (and sometimes interface) */
2452 if (ipa->address[0] == ':' && ipa->address[1] == 0)
2454 if (ipa->next && ipa->next->address[0] == 0 &&
2455 ipa->next->port == ipa->port)
2457 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
2458 (ipa = ipa->next)->log = NULL;
2460 else if (ipa->v6_include_v4)
2461 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
2463 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
2465 else if (ipa->address[0] == 0) /* v4 wildcard */
2466 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
2467 else /* check for previously-seen IP */
2469 ip_address_item * i2;
2470 for (i2 = addresses; i2 != ipa; i2 = i2->next)
2471 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
2472 && Ustrcmp(ipa->address, i2->address) == 0
2474 { /* found; append port to list */
2475 for (p = i2->log; *p; ) p++; /* end of existing string { */
2476 if (*--p == '}') *p = '\0'; /* drop EOL */
2477 while (isdigit(*--p)) ; /* char before port */
2479 i2->log = *p == ':' /* no list yet? { */
2480 ? string_sprintf("%.*s{%s,%d}",
2481 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
2482 : string_sprintf("%s,%d}", i2->log, ipa->port);
2486 if (i2 == ipa) /* first-time IP */
2487 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
2493 for (int j = 0, i; j < 2; j++)
2495 /* First time round, look for SMTP ports; second time round, look for
2496 SMTPS ports. For the first one of each, insert leading text. */
2501 p += sprintf(CS p, "SMTP on");
2504 if (smtps_ports > 0)
2505 p += sprintf(CS p, "%sSMTPS on",
2506 smtp_ports == 0 ? "" : " and for ");
2508 /* Now the information about the port (and sometimes interface) */
2510 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
2511 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
2513 p += sprintf(CS p, "%s", ipa->log);
2516 p += sprintf(CS p, " ...");
2519 log_write(0, LOG_MAIN,
2520 "exim %s daemon started: pid=%d, %s, listening for %s",
2521 version_string, getpid(), qinfo, big_buffer);
2522 set_process_info("daemon(%s): %s, listening for %s",
2523 version_string, qinfo, big_buffer);
2526 else /* no listening sockets, only queue-runs */
2528 const uschar * s = describe_queue_runners();
2529 log_write(0, LOG_MAIN,
2530 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
2531 version_string, getpid(), s);
2532 set_process_info("daemon(%s): %s, not listening", version_string, s);
2535 /* Do any work it might be useful to amortize over our children
2536 (eg: compile regex) */
2539 smtp_deliver_init(); /* Used for callouts */
2541 #ifndef DISABLE_DKIM
2543 # ifdef MEASURE_TIMING
2545 gettimeofday(&t0, NULL);
2548 # ifdef MEASURE_TIMING
2549 report_time_since(&t0, US"dkim_exim_init (delta)");
2554 #ifdef WITH_CONTENT_SCAN
2564 /* Add ancillary sockets to the set for select */
2566 poll_fd_count = listen_socket_count;
2568 if (tls_watch_fd >= 0)
2570 tls_watch_poll = &fd_polls[poll_fd_count++];
2571 tls_watch_poll->fd = tls_watch_fd;
2572 tls_watch_poll->events = POLLIN;
2575 if (daemon_notifier_fd >= 0)
2577 dnotify_poll = &fd_polls[poll_fd_count++];
2578 dnotify_poll->fd = daemon_notifier_fd;
2579 dnotify_poll->events = POLLIN;
2582 /* Close the log so it can be renamed and moved. In the few cases below where
2583 this long-running process writes to the log (always exceptional conditions), it
2584 closes the log afterwards, for the same reason. */
2588 DEBUG(D_any) debug_print_ids(US"daemon running with");
2590 /* Any messages accepted via this route are going to be SMTP. */
2594 #ifdef MEASURE_TIMING
2595 report_time_since(×tamp_startup, US"daemon loop start"); /* testcase 0022 */
2598 /* Enter the never-ending loop... */
2602 int nolisten_sleep = 60;
2605 daemon_die(); /* Does not return */
2607 /* This code is placed first in the loop, so that it gets obeyed at the
2608 start, before the first wait, for the queue-runner case, so that the first
2609 one can be started immediately.
2611 The other option is that we have an inetd wait timeout specified to -bw. */
2614 if (inetd_wait_timeout > 0)
2615 daemon_inetd_wtimeout(last_connection_time); /* Might not return */
2618 daemon_qrun(local_queue_run_max, fd_polls, listen_socket_count);
2621 /* Sleep till a connection happens if listening, and handle the connection if
2622 that is why we woke up. The FreeBSD operating system requires the use of
2623 select() before accept() because the latter function is not interrupted by
2624 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2625 OS do notice signals in accept() but it does no harm to have the select()
2626 in for all of them - and it won't then be a lurking problem for ports to
2627 new OS. In fact, the later addition of listening on specific interfaces only
2628 requires this way of working anyway. */
2630 if (f.daemon_listen)
2633 BOOL select_failed = FALSE;
2635 DEBUG(D_any) debug_printf("Listening...\n");
2637 /* In rare cases we may have had a SIGCHLD signal in the time between
2638 setting the handler (below) and getting back here. If so, pretend that the
2639 select() was interrupted so that we reap the child. This might still leave
2640 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
2641 only to do the reaping more quickly, it shouldn't result in anything other
2642 than a delay until something else causes a wake-up. */
2650 lcount = poll(fd_polls, poll_fd_count, -1);
2654 select_failed = TRUE;
2658 /* Clean up any subprocesses that may have terminated. We need to do this
2659 here so that smtp_accept_max_per_host works when a connection to that host
2660 has completed, and we are about to accept a new one. When this code was
2661 later in the sequence, a new connection could be rejected, even though an
2662 old one had just finished. Preserve the errno from any select() failure for
2663 the use of the common select/accept error processing below. */
2666 int select_errno = errno;
2667 handle_ending_processes();
2672 /* Create or rotate any required keys; handle (delayed) filewatch event */
2674 if ((old_tfd = tls_daemon_tick()) >= 0)
2675 for (struct pollfd * p = &fd_polls[listen_socket_count];
2676 p < fd_polls + poll_fd_count; p++)
2677 if (p->fd == old_tfd) { p->fd = tls_watch_fd ; break; }
2680 errno = select_errno;
2683 /* Loop for all the sockets that are currently ready to go. If select
2684 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2685 to use the common error code for select/accept below. */
2687 while (lcount-- > 0)
2689 int accept_socket = -1;
2691 struct sockaddr_in6 accepted;
2693 struct sockaddr_in accepted;
2698 #if !defined(DISABLE_TLS) && (defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT))
2699 if (tls_watch_poll && tls_watch_poll->revents & POLLIN)
2701 tls_watch_poll->revents = 0;
2702 tls_watch_trigger_time = time(NULL); /* Set up delayed event */
2703 tls_watch_discard_event(tls_watch_fd);
2704 break; /* to top of daemon loop */
2707 if (dnotify_poll && dnotify_poll->revents & POLLIN)
2709 dnotify_poll->revents = 0;
2710 sigalrm_seen = daemon_notification();
2711 break; /* to top of daemon loop */
2713 for (struct pollfd * p = fd_polls; p < fd_polls + listen_socket_count;
2715 if (p->revents & POLLIN)
2717 EXIM_SOCKLEN_T alen = sizeof(accepted);
2718 #if defined(__FreeBSD__) && defined(SO_LISTENQLEN)
2720 socklen_t blen = sizeof(backlog);
2722 if ( smtp_backlog_monitor > 0
2723 && getsockopt(p->fd, SOL_SOCKET, SO_LISTENQLEN, &backlog, &blen) == 0)
2726 debug_printf("listen fd %d queue curr %d\n", p->fd, backlog);
2727 smtp_listen_backlog = backlog;
2730 #elif defined(TCP_INFO) && defined(EXIM_HAVE_TCPI_UNACKED)
2732 socklen_t tlen = sizeof(ti);
2734 /* If monitoring the backlog is wanted, grab for later logging */
2736 smtp_listen_backlog = 0;
2737 if ( smtp_backlog_monitor > 0
2738 && getsockopt(p->fd, IPPROTO_TCP, TCP_INFO, &ti, &tlen) == 0)
2740 DEBUG(D_interface) debug_printf("listen fd %d queue max %u curr %u\n",
2741 p->fd, ti.tcpi_sacked, ti.tcpi_unacked);
2742 smtp_listen_backlog = ti.tcpi_unacked;
2746 accept_socket = accept(p->fd, (struct sockaddr *)&accepted, &alen);
2751 /* If select or accept has failed and this was not caused by an
2752 interruption, log the incident and try again. With asymmetric TCP/IP
2753 routing errors such as "No route to network" have been seen here. Also
2754 "connection reset by peer" has been seen. These cannot be classed as
2755 disastrous errors, but they could fill up a lot of log. The code in smail
2756 crashes the daemon after 10 successive failures of accept, on the grounds
2757 that some OS fail continuously. Exim originally followed suit, but this
2758 appears to have caused problems. Now it just keeps going, but instead of
2759 logging each error, it batches them up when they are continuous. */
2761 if (accept_socket < 0 && errno != EINTR)
2763 if (accept_retry_count == 0)
2765 accept_retry_errno = errno;
2766 accept_retry_select_failed = select_failed;
2768 else if ( errno != accept_retry_errno
2769 || select_failed != accept_retry_select_failed
2770 || accept_retry_count >= 50)
2772 log_write(0, LOG_MAIN | (accept_retry_count >= 50 ? LOG_PANIC : 0),
2773 "%d %s() failure%s: %s",
2775 accept_retry_select_failed ? "select" : "accept",
2776 accept_retry_count == 1 ? "" : "s",
2777 strerror(accept_retry_errno));
2779 accept_retry_count = 0;
2780 accept_retry_errno = errno;
2781 accept_retry_select_failed = select_failed;
2783 accept_retry_count++;
2785 else if (accept_retry_count > 0)
2787 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2789 accept_retry_select_failed ? "select" : "accept",
2790 accept_retry_count == 1 ? "" : "s",
2791 strerror(accept_retry_errno));
2793 accept_retry_count = 0;
2796 /* If select/accept succeeded, deal with the connection. */
2798 if (accept_socket >= 0)
2800 #ifdef TCP_QUICKACK /* Avoid pure-ACKs while in tls protocol pingpong phase */
2801 /* Unfortunately we cannot be certain to do this before a TLS-on-connect
2802 Client Hello arrives and is acked. We do it as early as possible. */
2803 (void) setsockopt(accept_socket, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
2805 if (inetd_wait_timeout)
2806 last_connection_time = time(NULL);
2807 handle_smtp_call(fd_polls, listen_socket_count, accept_socket,
2808 (struct sockaddr *)&accepted);
2813 /* If not listening, then just sleep for the queue interval. If we woke
2814 up early the last time for some other signal, it won't matter because
2815 the alarm signal will wake at the right time. This code originally used
2816 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2817 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2818 select() can be used as an interruptible sleep() on all versions of Unix. */
2823 poll(&p, 0, nolisten_sleep * 1000);
2824 handle_ending_processes();
2827 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2828 for itself, because it isn't doing the waiting itself. */
2832 sigchld_seen = FALSE;
2833 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
2836 /* Handle being woken by SIGHUP. We know at this point that the result
2837 of accept() has been dealt with, so we can re-exec exim safely, first
2838 closing the listening sockets so that they can be reused. Cancel any pending
2839 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2840 that another HUP in quick succession doesn't clobber the new daemon before it
2841 gets going. All log files get closed by the close-on-exec flag; however, if
2842 the exec fails, we need to close the logs. */
2846 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2848 close_daemon_sockets(daemon_notifier_fd, fd_polls, listen_socket_count);
2849 unlink_notifier_socket();
2851 signal(SIGHUP, SIG_IGN);
2852 sighup_argv[0] = exim_path;
2854 execv(CS exim_path, (char *const *)sighup_argv);
2855 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2856 getpid(), exim_path, strerror(errno));
2860 } /* End of main loop */
2862 /* Control never reaches here */
2867 /* End of exim_daemon.c */