1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) The Exim Maintainers 2020 - 2022 */
6 /* Copyright (c) University of Cambridge 1995 - 2018 */
7 /* See the file NOTICE for conditions of use and distribution. */
9 /* Functions concerned with running Exim as a daemon */
15 /* Structure for holding data for each SMTP connection */
17 typedef struct smtp_slot {
18 pid_t pid; /* pid of the spawned reception process */
19 uschar *host_address; /* address of the client host */
22 /* An empty slot for initializing (Standard C does not allow constructor
23 expressions in assignments except as initializers in declarations). */
25 static smtp_slot empty_smtp_slot = { .pid = 0, .host_address = NULL };
29 /*************************************************
30 * Local static variables *
31 *************************************************/
33 static SIGNAL_BOOL sigchld_seen;
34 static SIGNAL_BOOL sighup_seen;
35 static SIGNAL_BOOL sigterm_seen;
37 static int accept_retry_count = 0;
38 static int accept_retry_errno;
39 static BOOL accept_retry_select_failed;
41 static int queue_run_count = 0;
42 static pid_t *queue_pid_slots = NULL;
43 static smtp_slot *smtp_slots = NULL;
45 static BOOL write_pid = TRUE;
49 /*************************************************
51 *************************************************/
53 /* All this handler does is to set a flag and re-enable the signal.
55 Argument: the signal number
60 sighup_handler(int sig)
63 signal(SIGHUP, sighup_handler);
68 /*************************************************
69 * SIGCHLD handler for main daemon process *
70 *************************************************/
72 /* Don't re-enable the handler here, since we aren't doing the
73 waiting here. If the signal is re-enabled, there will just be an
74 infinite sequence of calls to this handler. The SIGCHLD signal is
75 used just as a means of waking up the daemon so that it notices
76 terminated subprocesses as soon as possible.
78 Argument: the signal number
83 main_sigchld_handler(int sig)
85 os_non_restarting_signal(SIGCHLD, SIG_DFL);
90 /* SIGTERM handler. Try to get the daemon pid file removed
94 main_sigterm_handler(int sig)
102 /*************************************************
103 * Unexpected errors in SMTP calls *
104 *************************************************/
106 /* This function just saves a bit of repetitious coding.
109 log_msg Text of message to be logged
110 smtp_msg Text of SMTP error message
111 was_errno The failing errno
117 never_error(uschar *log_msg, uschar *smtp_msg, int was_errno)
119 uschar *emsg = was_errno <= 0
120 ? US"" : string_sprintf(": %s", strerror(was_errno));
121 log_write(0, LOG_MAIN|LOG_PANIC, "%s%s", log_msg, emsg);
122 if (smtp_out) smtp_printf("421 %s\r\n", FALSE, smtp_msg);
128 /*************************************************
129 *************************************************/
131 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
133 unlink_notifier_socket(void)
135 uschar * s = expand_string(notifier_socket);
136 DEBUG(D_any) debug_printf("unlinking notifier socket %s\n", s);
143 close_daemon_sockets(int daemon_notifier_fd,
144 struct pollfd * fd_polls, int listen_socket_count)
146 if (daemon_notifier_fd >= 0)
148 (void) close(daemon_notifier_fd);
149 daemon_notifier_fd = -1;
150 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
151 unlink_notifier_socket();
155 for (int i = 0; i < listen_socket_count; i++) (void) close(fd_polls[i].fd);
159 /*************************************************
160 * Handle a connected SMTP call *
161 *************************************************/
163 /* This function is called when an SMTP connection has been accepted.
164 If there are too many, give an error message and close down. Otherwise
165 spin off a sub-process to handle the call. The list of listening sockets
166 is required so that they can be closed in the sub-process. Take care not to
167 leak store in this process - reset the stacking pool at the end.
170 fd_polls sockets which are listening for incoming calls
171 listen_socket_count count of listening sockets
172 accept_socket socket of the current accepted call
173 accepted socket information about the current call
179 handle_smtp_call(struct pollfd *fd_polls, int listen_socket_count,
180 int accept_socket, struct sockaddr *accepted)
183 union sockaddr_46 interface_sockaddr;
184 EXIM_SOCKLEN_T ifsize = sizeof(interface_sockaddr);
185 int dup_accept_socket = -1;
186 int max_for_this_host = 0;
187 int save_log_selector = *log_selector;
190 rmark reset_point = store_mark();
192 /* Make the address available in ASCII representation, and also fish out
195 sender_host_address = host_ntoa(-1, accepted, NULL, &sender_host_port);
196 DEBUG(D_any) debug_printf("Connection request from %s port %d\n",
197 sender_host_address, sender_host_port);
199 /* Set up the output stream, check the socket has duplicated, and set up the
200 input stream. These operations fail only the exceptional circumstances. Note
201 that never_error() won't use smtp_out if it is NULL. */
203 if (!(smtp_out = fdopen(accept_socket, "wb")))
205 never_error(US"daemon: fdopen() for smtp_out failed", US"", errno);
209 if ((dup_accept_socket = dup(accept_socket)) < 0)
211 never_error(US"daemon: couldn't dup socket descriptor",
212 US"Connection setup failed", errno);
216 if (!(smtp_in = fdopen(dup_accept_socket, "rb")))
218 never_error(US"daemon: fdopen() for smtp_in failed",
219 US"Connection setup failed", errno);
223 /* Get the data for the local interface address. Panic for most errors, but
224 "connection reset by peer" just means the connection went away. */
226 if (getsockname(accept_socket, (struct sockaddr *)(&interface_sockaddr),
229 log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC),
230 "getsockname() failed: %s", strerror(errno));
231 smtp_printf("421 Local problem: getsockname() failed; please try again later\r\n", FALSE);
235 interface_address = host_ntoa(-1, &interface_sockaddr, NULL, &interface_port);
236 DEBUG(D_interface) debug_printf("interface address=%s port=%d\n",
237 interface_address, interface_port);
239 /* Build a string identifying the remote host and, if requested, the port and
240 the local interface data. This is for logging; at the end of this function the
241 memory is reclaimed. */
243 whofrom = string_append(NULL, 3, "[", sender_host_address, "]");
245 if (LOGGING(incoming_port))
246 whofrom = string_fmt_append(whofrom, ":%d", sender_host_port);
248 if (LOGGING(incoming_interface))
249 whofrom = string_fmt_append(whofrom, " I=[%s]:%d",
250 interface_address, interface_port);
252 (void) string_from_gstring(whofrom); /* Terminate the newly-built string */
254 /* Check maximum number of connections. We do not check for reserved
255 connections or unacceptable hosts here. That is done in the subprocess because
256 it might take some time. */
258 if (smtp_accept_max > 0 && smtp_accept_count >= smtp_accept_max)
260 DEBUG(D_any) debug_printf("rejecting SMTP connection: count=%d max=%d\n",
261 smtp_accept_count, smtp_accept_max);
262 smtp_printf("421 Too many concurrent SMTP connections; "
263 "please try again later.\r\n", FALSE);
264 log_write(L_connection_reject,
265 LOG_MAIN, "Connection from %s refused: too many connections",
270 /* If a load limit above which only reserved hosts are acceptable is defined,
271 get the load average here, and if there are in fact no reserved hosts, do
272 the test right away (saves a fork). If there are hosts, do the check in the
273 subprocess because it might take time. */
275 if (smtp_load_reserve >= 0)
277 load_average = OS_GETLOADAVG();
278 if (!smtp_reserve_hosts && load_average > smtp_load_reserve)
280 DEBUG(D_any) debug_printf("rejecting SMTP connection: load average = %.2f\n",
281 (double)load_average/1000.0);
282 smtp_printf("421 Too much load; please try again later.\r\n", FALSE);
283 log_write(L_connection_reject,
284 LOG_MAIN, "Connection from %s refused: load average = %.2f",
285 whofrom->s, (double)load_average/1000.0);
290 /* Check that one specific host (strictly, IP address) is not hogging
291 resources. This is done here to prevent a denial of service attack by someone
292 forcing you to fork lots of times before denying service. The value of
293 smtp_accept_max_per_host is a string which is expanded. This makes it possible
294 to provide host-specific limits according to $sender_host address, but because
295 this is in the daemon mainline, only fast expansions (such as inline address
296 checks) should be used. The documentation is full of warnings. */
298 if (smtp_accept_max_per_host)
300 uschar *expanded = expand_string(smtp_accept_max_per_host);
303 if (!f.expand_string_forcedfail)
304 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
305 "failed for %s: %s", whofrom->s, expand_string_message);
307 /* For speed, interpret a decimal number inline here */
310 uschar *s = expanded;
312 max_for_this_host = max_for_this_host * 10 + *s++ - '0';
314 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
315 "for %s contains non-digit: %s", whofrom->s, expanded);
319 /* If we have fewer connections than max_for_this_host, we can skip the tedious
320 per host_address checks. Note that at this stage smtp_accept_count contains the
321 count of *other* connections, not including this one. */
323 if (max_for_this_host > 0 && smtp_accept_count >= max_for_this_host)
325 int host_accept_count = 0;
326 int other_host_count = 0; /* keep a count of non matches to optimise */
328 for (int i = 0; i < smtp_accept_max; ++i)
329 if (smtp_slots[i].host_address)
331 if (Ustrcmp(sender_host_address, smtp_slots[i].host_address) == 0)
336 /* Testing all these strings is expensive - see if we can drop out
337 early, either by hitting the target, or finding there are not enough
338 connections left to make the target. */
340 if ( host_accept_count >= max_for_this_host
341 || smtp_accept_count - other_host_count < max_for_this_host)
345 if (host_accept_count >= max_for_this_host)
347 DEBUG(D_any) debug_printf("rejecting SMTP connection: too many from this "
348 "IP address: count=%d max=%d\n",
349 host_accept_count, max_for_this_host);
350 smtp_printf("421 Too many concurrent SMTP connections "
351 "from this IP address; please try again later.\r\n", FALSE);
352 log_write(L_connection_reject,
353 LOG_MAIN, "Connection from %s refused: too many connections "
354 "from that IP address", whofrom->s);
360 /* OK, the connection count checks have been passed. Before we can fork the
361 accepting process, we must first log the connection if requested. This logging
362 used to happen in the subprocess, but doing that means that the value of
363 smtp_accept_count can be out of step by the time it is logged. So we have to do
364 the logging here and accept the performance cost. Note that smtp_accept_count
365 hasn't yet been incremented to take account of this connection.
367 In order to minimize the cost (because this is going to happen for every
368 connection), do a preliminary selector test here. This saves ploughing through
369 the generalized logging code each time when the selector is false. If the
370 selector is set, check whether the host is on the list for logging. If not,
371 arrange to unset the selector in the subprocess. */
373 if (LOGGING(smtp_connection))
375 uschar *list = hosts_connection_nolog;
376 memset(sender_host_cache, 0, sizeof(sender_host_cache));
377 if (list && verify_check_host(&list) == OK)
378 save_log_selector &= ~L_smtp_connection;
380 log_write(L_smtp_connection, LOG_MAIN, "SMTP connection from %s "
381 "(TCP/IP connection count = %d)", whofrom->s, smtp_accept_count + 1);
384 /* Now we can fork the accepting process; do a lookup tidy, just in case any
385 expansion above did a lookup. */
388 pid = exim_fork(US"daemon-accept");
390 /* Handle the child process */
394 int queue_only_reason = 0;
395 int old_pool = store_pool;
396 int save_debug_selector = debug_selector;
397 BOOL local_queue_only;
398 BOOL session_local_queue_only;
400 struct sigaction act;
403 smtp_accept_count++; /* So that it includes this process */
405 /* If the listen backlog was over the monitoring level, log it. */
407 if (smtp_listen_backlog > smtp_backlog_monitor)
408 log_write(0, LOG_MAIN, "listen backlog %d I=[%s]:%d",
409 smtp_listen_backlog, interface_address, interface_port);
411 /* May have been modified for the subprocess */
413 *log_selector = save_log_selector;
415 /* Get the local interface address into permanent store */
417 store_pool = POOL_PERM;
418 interface_address = string_copy(interface_address);
419 store_pool = old_pool;
421 /* Check for a tls-on-connect port */
423 if (host_is_tls_on_connect_port(interface_port)) tls_in.on_connect = TRUE;
425 /* Expand smtp_active_hostname if required. We do not do this any earlier,
426 because it may depend on the local interface address (indeed, that is most
427 likely what it depends on.) */
429 smtp_active_hostname = primary_hostname;
430 if (raw_active_hostname)
432 uschar * nah = expand_string(raw_active_hostname);
435 if (!f.expand_string_forcedfail)
437 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand \"%s\" "
438 "(smtp_active_hostname): %s", raw_active_hostname,
439 expand_string_message);
440 smtp_printf("421 Local configuration error; "
441 "please try again later.\r\n", FALSE);
444 exim_underbar_exit(EXIT_FAILURE);
447 else if (*nah) smtp_active_hostname = nah;
450 /* Initialize the queueing flags */
453 session_local_queue_only = queue_only;
455 /* Close the listening sockets, and set the SIGCHLD handler to SIG_IGN.
456 We also attempt to set things up so that children are automatically reaped,
457 but just in case this isn't available, there's a paranoid waitpid() in the
458 loop too (except for systems where we are sure it isn't needed). See the more
459 extensive comment before the reception loop in exim.c for a fuller
460 explanation of this logic. */
462 close_daemon_sockets(daemon_notifier_fd, fd_polls, listen_socket_count);
464 /* Set FD_CLOEXEC on the SMTP socket. We don't want any rogue child processes
465 to be able to communicate with them, under any circumstances. */
466 (void)fcntl(accept_socket, F_SETFD,
467 fcntl(accept_socket, F_GETFD) | FD_CLOEXEC);
468 (void)fcntl(dup_accept_socket, F_SETFD,
469 fcntl(dup_accept_socket, F_GETFD) | FD_CLOEXEC);
472 act.sa_handler = SIG_IGN;
473 sigemptyset(&(act.sa_mask));
474 act.sa_flags = SA_NOCLDWAIT;
475 sigaction(SIGCHLD, &act, NULL);
477 signal(SIGCHLD, SIG_IGN);
479 signal(SIGTERM, SIG_DFL);
480 signal(SIGINT, SIG_DFL);
482 /* Attempt to get an id from the sending machine via the RFC 1413
483 protocol. We do this in the sub-process in order not to hold up the
484 main process if there is any delay. Then set up the fullhost information
485 in case there is no HELO/EHLO.
487 If debugging is enabled only for the daemon, we must turn if off while
488 finding the id, but turn it on again afterwards so that information about the
489 incoming connection is output. */
491 if (f.debug_daemon) debug_selector = 0;
492 verify_get_ident(IDENT_PORT);
493 host_build_sender_fullhost();
494 debug_selector = save_debug_selector;
497 debug_printf("Process %d is handling incoming connection from %s\n",
498 (int)getpid(), sender_fullhost);
500 /* Now disable debugging permanently if it's required only for the daemon
503 if (f.debug_daemon) debug_selector = 0;
505 /* If there are too many child processes for immediate delivery,
506 set the session_local_queue_only flag, which is initialized from the
507 configured value and may therefore already be TRUE. Leave logging
508 till later so it will have a message id attached. Note that there is no
509 possibility of re-calculating this per-message, because the value of
510 smtp_accept_count does not change in this subprocess. */
512 if (smtp_accept_queue > 0 && smtp_accept_count > smtp_accept_queue)
514 session_local_queue_only = TRUE;
515 queue_only_reason = 1;
518 /* Handle the start of the SMTP session, then loop, accepting incoming
519 messages from the SMTP connection. The end will come at the QUIT command,
520 when smtp_setup_msg() returns 0. A break in the connection causes the
521 process to die (see accept.c).
523 NOTE: We do *not* call smtp_log_no_mail() if smtp_start_session() fails,
524 because a log line has already been written for all its failure exists
525 (usually "connection refused: <reason>") and writing another one is
526 unnecessary clutter. */
528 if (!smtp_start_session())
532 exim_underbar_exit(EXIT_SUCCESS);
538 message_id[0] = 0; /* Clear out any previous message_id */
539 reset_point = store_mark(); /* Save current store high water point */
542 debug_printf("Process %d is ready for new message\n", (int)getpid());
544 /* Smtp_setup_msg() returns 0 on QUIT or if the call is from an
545 unacceptable host or if an ACL "drop" command was triggered, -1 on
546 connection lost, and +1 on validly reaching DATA. Receive_msg() almost
547 always returns TRUE when smtp_input is true; just retry if no message was
548 accepted (can happen for invalid message parameters). However, it can yield
549 FALSE if the connection was forcibly dropped by the DATA ACL. */
551 if ((rc = smtp_setup_msg()) > 0)
553 BOOL ok = receive_msg(FALSE);
554 search_tidyup(); /* Close cached databases */
555 if (!ok) /* Connection was dropped */
557 cancel_cutthrough_connection(TRUE, US"receive dropped");
559 smtp_log_no_mail(); /* Log no mail if configured */
560 exim_underbar_exit(EXIT_SUCCESS);
562 if (message_id[0] == 0) continue; /* No message was accepted */
564 else /* bad smtp_setup_msg() */
568 int fd = fileno(smtp_in);
572 /* drain socket, for clean TCP FINs */
573 if (fcntl(fd, F_SETFL, O_NONBLOCK) == 0)
574 for(int i = 16; read(fd, buf, sizeof(buf)) > 0 && i > 0; ) i--;
576 cancel_cutthrough_connection(TRUE, US"message setup dropped");
578 smtp_log_no_mail(); /* Log no mail if configured */
580 /*XXX should we pause briefly, hoping that the client will be the
581 active TCP closer hence get the TCP_WAIT endpoint? */
582 DEBUG(D_receive) debug_printf("SMTP>>(close on process exit)\n");
583 exim_underbar_exit(rc ? EXIT_FAILURE : EXIT_SUCCESS);
586 /* Show the recipients when debugging */
591 debug_printf("Sender: %s\n", sender_address);
594 debug_printf("Recipients:\n");
595 for (int i = 0; i < recipients_count; i++)
596 debug_printf(" %s\n", recipients_list[i].address);
600 /* A message has been accepted. Clean up any previous delivery processes
601 that have completed and are defunct, on systems where they don't go away
602 by themselves (see comments when setting SIG_IGN above). On such systems
603 (if any) these delivery processes hang around after termination until
604 the next message is received. */
606 #ifndef SIG_IGN_WORKS
607 while (waitpid(-1, NULL, WNOHANG) > 0);
610 /* Reclaim up the store used in accepting this message */
613 int r = receive_messagecount;
614 BOOL q = f.queue_only_policy;
615 smtp_reset(reset_point);
617 f.queue_only_policy = q;
618 receive_messagecount = r;
621 /* If queue_only is set or if there are too many incoming connections in
622 existence, session_local_queue_only will be TRUE. If it is not, check
623 whether we have received too many messages in this session for immediate
626 if (!session_local_queue_only &&
627 smtp_accept_queue_per_connection > 0 &&
628 receive_messagecount > smtp_accept_queue_per_connection)
630 session_local_queue_only = TRUE;
631 queue_only_reason = 2;
634 /* Initialize local_queue_only from session_local_queue_only. If it is not
635 true, and queue_only_load is set, check that the load average is below it.
636 If local_queue_only is set by this means, we also set if for the session if
637 queue_only_load_latch is true (the default). This means that, once set,
638 local_queue_only remains set for any subsequent messages on the same SMTP
639 connection. This is a deliberate choice; even though the load average may
640 fall, it doesn't seem right to deliver later messages on the same call when
641 not delivering earlier ones. However, the are special circumstances such as
642 very long-lived connections from scanning appliances where this is not the
643 best strategy. In such cases, queue_only_load_latch should be set false. */
645 if ( !(local_queue_only = session_local_queue_only)
646 && queue_only_load >= 0
647 && (local_queue_only = (load_average = OS_GETLOADAVG()) > queue_only_load)
650 queue_only_reason = 3;
651 if (queue_only_load_latch) session_local_queue_only = TRUE;
654 /* Log the queueing here, when it will get a message id attached, but
655 not if queue_only is set (case 0). */
657 if (local_queue_only) switch(queue_only_reason)
659 case 1: log_write(L_delay_delivery,
660 LOG_MAIN, "no immediate delivery: too many connections "
661 "(%d, max %d)", smtp_accept_count, smtp_accept_queue);
664 case 2: log_write(L_delay_delivery,
665 LOG_MAIN, "no immediate delivery: more than %d messages "
666 "received in one connection", smtp_accept_queue_per_connection);
669 case 3: log_write(L_delay_delivery,
670 LOG_MAIN, "no immediate delivery: load average %.2f",
671 (double)load_average/1000.0);
675 /* If a delivery attempt is required, spin off a new process to handle it.
676 If we are not root, we have to re-exec exim unless deliveries are being
677 done unprivileged. */
679 else if ( (!f.queue_only_policy || f.queue_smtp)
680 && !f.deliver_freeze)
684 /* We used to flush smtp_out before forking so that buffered data was not
685 duplicated, but now we want to pipeline the responses for data and quit.
686 Instead, hard-close the fd underlying smtp_out right after fork to discard
689 if ((dpid = exim_fork(US"daemon-accept-delivery")) == 0)
691 (void)fclose(smtp_in);
692 (void)close(fileno(smtp_out));
693 (void)fclose(smtp_out);
694 smtp_in = smtp_out = NULL;
696 /* Don't ever molest the parent's SSL connection, but do clean up
697 the data structures if necessary. */
700 tls_close(NULL, TLS_NO_SHUTDOWN);
703 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
705 signal(SIGHUP, SIG_DFL);
706 signal(SIGCHLD, SIG_DFL);
707 signal(SIGTERM, SIG_DFL);
708 signal(SIGINT, SIG_DFL);
710 if (geteuid() != root_uid && !deliver_drop_privilege)
712 signal(SIGALRM, SIG_DFL);
713 delivery_re_exec(CEE_EXEC_PANIC);
714 /* Control does not return here. */
717 /* No need to re-exec; SIGALRM remains set to the default handler */
719 (void) deliver_message(message_id, FALSE, FALSE);
721 exim_underbar_exit(EXIT_SUCCESS);
726 release_cutthrough_connection(US"passed for delivery");
727 DEBUG(D_any) debug_printf("forked delivery process %d\n", (int)dpid);
731 cancel_cutthrough_connection(TRUE, US"delivery fork failed");
732 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: delivery process fork "
733 "failed: %s", strerror(errno));
740 /* Carrying on in the parent daemon process... Can't do much if the fork
741 failed. Otherwise, keep count of the number of accepting processes and
742 remember the pid for ticking off when the child completes. */
745 never_error(US"daemon: accept process fork failed", US"Fork failed", errno);
748 for (int i = 0; i < smtp_accept_max; ++i)
749 if (smtp_slots[i].pid <= 0)
751 smtp_slots[i].pid = pid;
752 /* Connection closes come asyncronously, so we cannot stack this store */
753 if (smtp_accept_max_per_host)
754 smtp_slots[i].host_address = string_copy_malloc(sender_host_address);
758 DEBUG(D_any) debug_printf("%d SMTP accept process%s running\n",
759 smtp_accept_count, smtp_accept_count == 1 ? "" : "es");
762 /* Get here via goto in error cases */
766 /* Close the streams associated with the socket which will also close the
767 socket fds in this process. We can't do anything if fclose() fails, but
768 logging brings it to someone's attention. However, "connection reset by peer"
769 isn't really a problem, so skip that one. On Solaris, a dropped connection can
770 manifest itself as a broken pipe, so drop that one too. If the streams don't
771 exist, something went wrong while setting things up. Make sure the socket
772 descriptors are closed, in order to drop the connection. */
776 if (fclose(smtp_out) != 0 && errno != ECONNRESET && errno != EPIPE)
777 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_out) failed: %s",
781 else (void)close(accept_socket);
785 if (fclose(smtp_in) != 0 && errno != ECONNRESET && errno != EPIPE)
786 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_in) failed: %s",
790 else (void)close(dup_accept_socket);
792 /* Release any store used in this process, including the store used for holding
793 the incoming host address and an expanded active_hostname. */
796 interface_address = sender_host_name = sender_host_address = NULL;
797 store_reset(reset_point);
803 /*************************************************
804 * Check wildcard listen special cases *
805 *************************************************/
807 /* This function is used when binding and listening on lists of addresses and
808 ports. It tests for special cases of wildcard listening, when IPv4 and IPv6
809 sockets may interact in different ways in different operating systems. It is
810 passed an error number, the list of listening addresses, and the current
811 address. Two checks are available: for a previous wildcard IPv6 address, or for
812 a following wildcard IPv4 address, in both cases on the same port.
814 In practice, pairs of wildcard addresses should be adjacent in the address list
815 because they are sorted that way below.
819 addresses the list of addresses
820 ipa the current IP address
821 back if TRUE, check for previous wildcard IPv6 address
822 if FALSE, check for a following wildcard IPv4 address
824 Returns: TRUE or FALSE
828 check_special_case(int eno, ip_address_item *addresses, ip_address_item *ipa,
831 ip_address_item *ipa2;
833 /* For the "back" case, if the failure was "address in use" for a wildcard IPv4
834 address, seek a previous IPv6 wildcard address on the same port. As it is
835 previous, it must have been successfully bound and be listening. Flag it as a
836 "6 including 4" listener. */
840 if (eno != EADDRINUSE || ipa->address[0] != 0) return FALSE;
841 for (ipa2 = addresses; ipa2 != ipa; ipa2 = ipa2->next)
843 if (ipa2->address[1] == 0 && ipa2->port == ipa->port)
845 ipa2->v6_include_v4 = TRUE;
851 /* For the "forward" case, if the current address is a wildcard IPv6 address,
852 we seek a following wildcard IPv4 address on the same port. */
856 if (ipa->address[0] != ':' || ipa->address[1] != 0) return FALSE;
857 for (ipa2 = ipa->next; ipa2 != NULL; ipa2 = ipa2->next)
858 if (ipa2->address[0] == 0 && ipa->port == ipa2->port) return TRUE;
867 /*************************************************
868 * Handle terminating subprocesses *
869 *************************************************/
871 /* Handle the termination of child processes. Theoretically, this need be done
872 only when sigchld_seen is TRUE, but rumour has it that some systems lose
873 SIGCHLD signals at busy times, so to be on the safe side, this function is
874 called each time round. It shouldn't be too expensive.
881 handle_ending_processes(void)
886 while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
890 debug_printf("child %d ended: status=0x%x\n", (int)pid, status);
892 if (WIFEXITED(status))
893 debug_printf(" normal exit, %d\n", WEXITSTATUS(status));
894 else if (WIFSIGNALED(status))
895 debug_printf(" signal exit, signal %d%s\n", WTERMSIG(status),
896 WCOREDUMP(status) ? " (core dumped)" : "");
900 /* If it's a listening daemon for which we are keeping track of individual
901 subprocesses, deal with an accepting process that has terminated. */
906 for (i = 0; i < smtp_accept_max; i++)
907 if (smtp_slots[i].pid == pid)
909 if (smtp_slots[i].host_address)
910 store_free(smtp_slots[i].host_address);
911 smtp_slots[i] = empty_smtp_slot;
912 if (--smtp_accept_count < 0) smtp_accept_count = 0;
913 DEBUG(D_any) debug_printf("%d SMTP accept process%s now running\n",
914 smtp_accept_count, (smtp_accept_count == 1)? "" : "es");
917 if (i < smtp_accept_max) continue; /* Found an accepting process */
920 /* If it wasn't an accepting process, see if it was a queue-runner
921 process that we are tracking. */
925 int max = atoi(CS expand_string(queue_run_max));
926 for (int i = 0; i < max; i++)
927 if (queue_pid_slots[i] == pid)
929 queue_pid_slots[i] = 0;
930 if (--queue_run_count < 0) queue_run_count = 0;
931 DEBUG(D_any) debug_printf("%d queue-runner process%s now running\n",
932 queue_run_count, (queue_run_count == 1)? "" : "es");
941 set_pid_file_path(void)
943 if (override_pid_file_path)
944 pid_file_path = override_pid_file_path;
947 pid_file_path = string_sprintf("%s/exim-daemon.pid", spool_directory);
949 if (pid_file_path[0] != '/')
950 log_write(0, LOG_PANIC_DIE, "pid file path %s must be absolute\n", pid_file_path);
954 enum pid_op { PID_WRITE, PID_CHECK, PID_DELETE };
956 /* Do various pid file operations as safe as possible. Ideally we'd just
957 drop the privileges for creation of the pid file and not care at all about removal of
959 Returns: true on success, false + errno==EACCES otherwise
963 operate_on_pid_file(const enum pid_op operation, const pid_t pid)
965 char pid_line[sizeof(int) * 3 + 2];
966 const int pid_len = snprintf(pid_line, sizeof(pid_line), "%d\n", (int)pid);
967 BOOL lines_match = FALSE;
968 uschar * path, * base, * dir;
970 const int dir_flags = O_RDONLY | O_NONBLOCK;
971 const int base_flags = O_NOFOLLOW | O_NONBLOCK;
972 const mode_t base_mode = 0644;
974 int cwd_fd = -1, dir_fd = -1, base_fd = -1;
975 BOOL success = FALSE;
979 if (!f.running_in_test_harness && real_uid != root_uid && real_uid != exim_uid) goto cleanup;
980 if (pid_len < 2 || pid_len >= (int)sizeof(pid_line)) goto cleanup;
982 path = string_copy(pid_file_path);
983 if ((base = Ustrrchr(path, '/')) == NULL) /* should not happen, but who knows */
984 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid file path \"%s\" does not contain a '/'", pid_file_path);
986 dir = base != path ? path : US"/";
989 if (!dir || !*dir || *dir != '/') goto cleanup;
990 if (!base || !*base || Ustrchr(base, '/') != NULL) goto cleanup;
992 cwd_fd = open(".", dir_flags);
993 if (cwd_fd < 0 || fstat(cwd_fd, &sb) != 0 || !S_ISDIR(sb.st_mode)) goto cleanup;
994 dir_fd = open(CS dir, dir_flags);
995 if (dir_fd < 0 || fstat(dir_fd, &sb) != 0 || !S_ISDIR(sb.st_mode)) goto cleanup;
998 if (fchdir(dir_fd) != 0) goto cleanup;
999 base_fd = open(CS base, O_RDONLY | base_flags);
1000 if (fchdir(cwd_fd) != 0)
1001 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1005 char line[sizeof(pid_line)];
1008 if (fstat(base_fd, &sb) != 0 || !S_ISREG(sb.st_mode)) goto cleanup;
1009 if ((sb.st_mode & 07777) != base_mode || sb.st_nlink != 1) goto cleanup;
1010 if (sb.st_size < 2 || sb.st_size >= (off_t)sizeof(line)) goto cleanup;
1012 len = read(base_fd, line, sizeof(line));
1013 if (len != (ssize_t)sb.st_size) goto cleanup;
1016 if (strspn(line, "0123456789") != (size_t)len-1) goto cleanup;
1017 if (line[len-1] != '\n') goto cleanup;
1018 lines_match = len == pid_len && strcmp(line, pid_line) == 0;
1021 if (operation == PID_WRITE)
1028 /* emulate unlinkat */
1029 if (fchdir(dir_fd) != 0) goto cleanup;
1030 error = unlink(CS base);
1031 if (fchdir(cwd_fd) != 0)
1032 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1033 if (error) goto cleanup;
1034 (void)close(base_fd);
1037 /* emulate openat */
1038 if (fchdir(dir_fd) != 0) goto cleanup;
1039 base_fd = open(CS base, O_WRONLY | O_CREAT | O_EXCL | base_flags, base_mode);
1040 if (fchdir(cwd_fd) != 0)
1041 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1042 if (base_fd < 0) goto cleanup;
1043 if (fchmod(base_fd, base_mode) != 0) goto cleanup;
1044 if (write(base_fd, pid_line, pid_len) != pid_len) goto cleanup;
1045 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1050 if (!lines_match) goto cleanup;
1051 if (operation == PID_DELETE)
1054 /* emulate unlinkat */
1055 if (fchdir(dir_fd) != 0) goto cleanup;
1056 error = unlink(CS base);
1057 if (fchdir(cwd_fd) != 0)
1058 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1059 if (error) goto cleanup;
1067 if (cwd_fd >= 0) (void)close(cwd_fd);
1068 if (dir_fd >= 0) (void)close(dir_fd);
1069 if (base_fd >= 0) (void)close(base_fd);
1074 /* Remove the daemon's pidfile. Note: runs with root privilege,
1075 as a direct child of the daemon. Does not return. */
1078 delete_pid_file(void)
1080 const BOOL success = operate_on_pid_file(PID_DELETE, getppid());
1083 debug_printf("delete pid file %s %s: %s\n", pid_file_path,
1084 success ? "success" : "failure", strerror(errno));
1086 exim_exit(EXIT_SUCCESS);
1090 /* Called by the daemon; exec a child to get the pid file deleted
1091 since we may require privs for the containing directory */
1098 DEBUG(D_any) debug_printf("SIGTERM/SIGINT seen\n");
1099 #if !defined(DISABLE_TLS) && (defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT))
1100 tls_watch_invalidate();
1103 if (daemon_notifier_fd >= 0)
1105 close(daemon_notifier_fd);
1106 daemon_notifier_fd = -1;
1107 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1108 unlink_notifier_socket();
1112 if (f.running_in_test_harness || write_pid)
1114 if ((pid = exim_fork(US"daemon-del-pidfile")) == 0)
1116 if (override_pid_file_path)
1117 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 3,
1118 "-oP", override_pid_file_path, "-oPX");
1120 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 1, "-oPX");
1122 /* Control never returns here. */
1125 child_close(pid, 1);
1127 exim_exit(EXIT_SUCCESS);
1131 /*************************************************
1132 * Listener socket for local work prompts *
1133 *************************************************/
1136 daemon_client_sockname(struct sockaddr_un * sup, uschar ** sname)
1138 #ifdef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1139 sup->sun_path[0] = 0; /* Abstract local socket addr - Linux-specific? */
1140 return offsetof(struct sockaddr_un, sun_path) + 1
1141 + snprintf(sup->sun_path+1, sizeof(sup->sun_path)-1, "exim_%d", getpid());
1143 *sname = string_sprintf("%s/p_%d", spool_directory, getpid());
1144 return offsetof(struct sockaddr_un, sun_path)
1145 + snprintf(sup->sun_path, sizeof(sup->sun_path), "%s", sname);
1150 daemon_notifier_sockname(struct sockaddr_un * sup)
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, "%s",
1156 expand_string(notifier_socket));
1158 return offsetof(struct sockaddr_un, sun_path)
1159 + snprintf(sup->sun_path, sizeof(sup->sun_path), "%s",
1160 expand_string(notifier_socket));
1166 daemon_notifier_socket(void)
1169 const uschar * where;
1170 struct sockaddr_un sa_un = {.sun_family = AF_UNIX};
1173 if (!notifier_socket || !*notifier_socket)
1175 DEBUG(D_any) debug_printf("-oY used so not creating notifier socket\n");
1178 if (override_local_interfaces && !override_pid_file_path)
1181 debug_printf("-oX used without -oP so not creating notifier socket\n");
1185 DEBUG(D_any) debug_printf("creating notifier socket\n");
1188 if ((fd = socket(PF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0)
1189 { where = US"socket"; goto bad; }
1191 if ((fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0)
1192 { where = US"socket"; goto bad; }
1193 (void)fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
1196 len = daemon_notifier_sockname(&sa_un);
1198 #ifdef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1199 DEBUG(D_any) debug_printf(" @%s\n", sa_un.sun_path+1);
1200 #else /* filesystem-visible and persistent; will neeed removal */
1201 DEBUG(D_any) debug_printf(" %s\n", sa_un.sun_path);
1204 if (bind(fd, (const struct sockaddr *)&sa_un, (socklen_t)len) < 0)
1205 { where = US"bind"; goto bad; }
1207 #ifdef SO_PASSCRED /* Linux */
1208 if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0)
1209 { where = US"SO_PASSCRED"; goto bad2; }
1210 #elif defined(LOCAL_CREDS) /* FreeBSD-ish */
1211 if (setsockopt(fd, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
1212 { where = US"LOCAL_CREDS"; goto bad2; }
1215 /* debug_printf("%s: fd %d\n", __FUNCTION__, fd); */
1216 daemon_notifier_fd = fd;
1220 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1221 Uunlink(sa_un.sun_path);
1224 log_write(0, LOG_MAIN|LOG_PANIC, "%s %s: %s",
1225 __FUNCTION__, where, strerror(errno));
1231 static uschar queuerun_msgid[MESSAGE_ID_LENGTH+1];
1233 /* The notifier socket has something to read. Pull the message from it, decode
1236 Return TRUE if a sigalrm should be emulated */
1239 daemon_notification(void)
1241 uschar buf[256], cbuf[256];
1242 struct sockaddr_un sa_un;
1243 struct iovec iov = {.iov_base = buf, .iov_len = sizeof(buf)-1};
1244 struct msghdr msg = { .msg_name = &sa_un,
1245 .msg_namelen = sizeof(sa_un),
1248 .msg_control = cbuf,
1249 .msg_controllen = sizeof(cbuf)
1253 buf[sizeof(buf)-1] = 0;
1254 if ((sz = recvmsg(daemon_notifier_fd, &msg, 0)) <= 0) return FALSE;
1255 if (sz >= sizeof(buf)) return FALSE;
1258 debug_printf("addrlen %d\n", msg.msg_namelen);
1260 DEBUG(D_queue_run) debug_printf("%s from addr '%s%.*s'\n", __FUNCTION__,
1261 *sa_un.sun_path ? "" : "@",
1262 (int)msg.msg_namelen - (*sa_un.sun_path ? 0 : 1),
1263 sa_un.sun_path + (*sa_un.sun_path ? 0 : 1));
1265 /* Refuse to handle the item unless the peer has good credentials */
1266 #ifdef SCM_CREDENTIALS
1267 # define EXIM_SCM_CR_TYPE SCM_CREDENTIALS
1268 #elif defined(LOCAL_CREDS) && defined(SCM_CREDS)
1269 # define EXIM_SCM_CR_TYPE SCM_CREDS
1271 /* The OS has no way to get the creds of the caller (for a unix/datagram socket.
1272 Punt; don't try to check. */
1275 #ifdef EXIM_SCM_CR_TYPE
1276 for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg);
1278 cp = CMSG_NXTHDR(&msg, cp))
1279 if (cp->cmsg_level == SOL_SOCKET && cp->cmsg_type == EXIM_SCM_CR_TYPE)
1281 # ifdef SCM_CREDENTIALS /* Linux */
1282 struct ucred * cr = (struct ucred *) CMSG_DATA(cp);
1283 if (cr->uid && cr->uid != exim_uid)
1285 DEBUG(D_queue_run) debug_printf("%s: sender creds pid %d uid %d gid %d\n",
1286 __FUNCTION__, (int)cr->pid, (int)cr->uid, (int)cr->gid);
1288 # elif defined(LOCAL_CREDS) /* BSD-ish */
1289 struct sockcred * cr = (struct sockcred *) CMSG_DATA(cp);
1290 if (cr->sc_uid && cr->sc_uid != exim_uid)
1292 DEBUG(D_queue_run) debug_printf("%s: sender creds pid ??? uid %d gid %d\n",
1293 __FUNCTION__, (int)cr->sc_uid, (int)cr->sc_gid);
1303 #ifndef DISABLE_QUEUE_RAMP
1304 case NOTIFY_MSG_QRUN:
1305 /* this should be a message_id */
1307 debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1);
1308 memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1);
1312 case NOTIFY_QUEUE_SIZE_REQ:
1315 int len = snprintf(CS buf, sizeof(buf), "%u", queue_count_cached());
1318 debug_printf("%s: queue size request: %s\n", __FUNCTION__, buf);
1320 if (sendto(daemon_notifier_fd, buf, len, 0,
1321 (const struct sockaddr *)&sa_un, msg.msg_namelen) < 0)
1322 log_write(0, LOG_MAIN|LOG_PANIC,
1323 "%s: sendto: %s\n", __FUNCTION__, strerror(errno));
1328 regex_at_daemon(buf);
1336 /*************************************************
1337 * Exim Daemon Mainline *
1338 *************************************************/
1340 /* The daemon can do two jobs, either of which is optional:
1342 (1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1343 each one. This is requested by the -bd option, with -oX specifying the SMTP
1344 port on which to listen (for testing).
1346 (2) Spawns a queue-running process every so often. This is controlled by the
1347 -q option with a an interval time. (If no time is given, a single queue run
1348 is done from the main function, and control doesn't get here.)
1350 Root privilege is required in order to attach to port 25. Some systems require
1351 it when calling socket() rather than bind(). To cope with all cases, we run as
1352 root for both socket() and bind(). Some systems also require root in order to
1353 write to the pid file directory. This function must therefore be called as root
1354 if it is to work properly in all circumstances. Once the socket is bound and
1355 the pid file written, root privilege is given up if there is an exim uid.
1357 There are no arguments to this function, and it never returns. */
1363 struct pollfd * fd_polls, * tls_watch_poll = NULL, * dnotify_poll = NULL;
1364 int listen_socket_count = 0, poll_fd_count;
1365 ip_address_item * addresses = NULL;
1366 time_t last_connection_time = (time_t)0;
1367 int local_queue_run_max = atoi(CS expand_string(queue_run_max));
1369 process_purpose = US"daemon";
1371 /* If any debugging options are set, turn on the D_pid bit so that all
1372 debugging lines get the pid added. */
1374 DEBUG(D_any|D_v) debug_selector |= D_pid;
1376 /* Allocate enough pollstructs for inetd mode plus the ancillary sockets;
1377 also used when there are no listen sockets. */
1379 fd_polls = store_get(sizeof(struct pollfd) * 3, GET_UNTAINTED);
1381 if (f.inetd_wait_mode)
1383 listen_socket_count = 1;
1385 if (dup2(0, 3) == -1)
1386 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1387 "failed to dup inetd socket safely away: %s", strerror(errno));
1390 fd_polls[0].events = POLLIN;
1396 if (debug_file == stderr)
1398 /* need a call to log_write before call to open debug_file, so that
1399 log.c:file_path has been initialised. This is unfortunate. */
1400 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1404 exim_nullstd(); /* re-open fd2 after we just closed it again */
1405 debug_logging_activate(US"-wait", NULL);
1408 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1410 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1411 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1414 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1415 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1420 if (f.inetd_wait_mode || f.daemon_listen)
1422 /* If any option requiring a load average to be available during the
1423 reception of a message is set, call os_getloadavg() while we are root
1424 for those OS for which this is necessary the first time it is called (in
1425 order to perform an "open" on the kernel memory file). */
1427 #ifdef LOAD_AVG_NEEDS_ROOT
1428 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1429 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1430 (void)os_getloadavg();
1435 /* Do the preparation for setting up a listener on one or more interfaces, and
1436 possible on various ports. This is controlled by the combination of
1437 local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1438 (which is a list of default ports to use for those items in local_interfaces
1439 that do not specify a port). The -oX command line option can be used to
1440 override one or both of these options.
1442 If local_interfaces is not set, the default is to listen on all interfaces.
1443 When it is set, it can include "all IPvx interfaces" as an item. This is useful
1444 when different ports are in use.
1446 It turns out that listening on all interfaces is messy in an IPv6 world,
1447 because several different implementation approaches have been taken. This code
1448 is now supposed to work with all of them. The point of difference is whether an
1449 IPv6 socket that is listening on all interfaces will receive incoming IPv4
1450 calls or not. We also have to cope with the case when IPv6 libraries exist, but
1451 there is no IPv6 support in the kernel.
1453 . On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1454 addresses. However, if an IPv4 socket is also listening on all interfaces,
1455 calls are directed to the appropriate socket.
1457 . On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1458 give them as mapped addresses, but an attempt also to listen on an IPv4
1459 socket on all interfaces causes an error.
1461 . On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1462 two sockets if you want to accept both kinds of call.
1464 . FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1465 can be turned off, to make it behave like the versions of Linux described
1468 . I heard a report that the USAGI IPv6 stack for Linux has implemented
1471 So, what we do when IPv6 is supported is as follows:
1473 (1) After it is set up, the list of interfaces is scanned for wildcard
1474 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1475 port, the list is re-arranged so that they are together, with the IPv6
1478 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1479 carry on if an IPv4 wildcard socket for the same port follows later in the
1480 list. This allows Exim to carry on in the case when the kernel has no IPv6
1483 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1484 option is defined. However, if setting fails, carry on regardless (but log
1487 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1490 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1491 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1492 port (which must have succeeded or we wouldn't have got this far), we
1493 assume we are in the situation where just a single socket is permitted,
1494 and ignore the error.
1498 The preparation code decodes options and sets up the relevant data. We do this
1499 first, so that we can return non-zero if there are any syntax errors, and also
1502 if (f.daemon_listen && !f.inetd_wait_mode)
1504 int *default_smtp_port;
1508 const uschar * list;
1509 uschar *local_iface_source = US"local_interfaces";
1510 ip_address_item *ipa;
1511 ip_address_item **pipa;
1513 /* If -oX was used, disable the writing of a pid file unless -oP was
1514 explicitly used to force it. Then scan the string given to -oX. Any items
1515 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1516 Any other items are used to override local_interfaces. */
1518 if (override_local_interfaces)
1520 gstring * new_smtp_port = NULL;
1521 gstring * new_local_interfaces = NULL;
1523 if (!override_pid_file_path) write_pid = FALSE;
1525 list = override_local_interfaces;
1527 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
1530 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
1536 *gp = string_catn(*gp, US"<", 1);
1539 *gp = string_catn(*gp, joinstr, 2);
1540 *gp = string_cat (*gp, s);
1545 daemon_smtp_port = string_from_gstring(new_smtp_port);
1546 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1550 if (new_local_interfaces)
1552 local_interfaces = string_from_gstring(new_local_interfaces);
1553 local_iface_source = US"-oX data";
1554 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1559 /* Create a list of default SMTP ports, to be used if local_interfaces
1560 contains entries without explicit ports. First count the number of ports, then
1561 build a translated list in a vector. */
1563 list = daemon_smtp_port;
1565 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
1567 default_smtp_port = store_get((pct+1) * sizeof(int), GET_UNTAINTED);
1568 list = daemon_smtp_port;
1571 (s = string_nextinlist(&list, &sep, NULL, 0));
1577 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1578 if (end != s + Ustrlen(s))
1579 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1583 struct servent *smtp_service = getservbyname(CS s, "tcp");
1585 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1586 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1589 default_smtp_port[pct] = 0;
1591 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1593 list = tls_in.on_connect_ports;
1595 /* the list isn't expanded so cannot be tainted. If it ever is we will trap here */
1596 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1601 list = tls_in.on_connect_ports;
1602 tls_in.on_connect_ports = NULL;
1604 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1608 struct servent * smtp_service = getservbyname(CS s, "tcp");
1610 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1611 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
1613 g = string_append_listele(g, ':', s);
1616 tls_in.on_connect_ports = g->s;
1620 /* Create the list of local interfaces, possibly with ports included. This
1621 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1622 values are converted below. */
1624 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1626 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1627 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1628 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1629 anyway, but we need to know which are the wildcard addresses, and the shorter
1632 In the same scan, fill in missing port numbers from the default list. When
1633 there is more than one item in the list, extra items are created. */
1635 for (ipa = addresses; ipa; ipa = ipa->next)
1637 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1638 ipa->address[0] = 0;
1639 else if (Ustrcmp(ipa->address, "::0") == 0)
1641 ipa->address[0] = ':';
1642 ipa->address[1] = 0;
1645 if (ipa->port > 0) continue;
1647 if (daemon_smtp_port[0] <= 0)
1648 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1649 "%s and daemon_smtp_port is unset; cannot start daemon",
1650 ipa->address[0] == 0 ? US"\"all IPv4\"" :
1651 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
1653 ipa->port = default_smtp_port[0];
1654 for (int i = 1; default_smtp_port[i] > 0; i++)
1656 ip_address_item * new = store_get(sizeof(ip_address_item), GET_UNTAINTED);
1658 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1659 new->port = default_smtp_port[i];
1660 new->next = ipa->next;
1666 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1667 wildcard for the same port, ensure that (a) they are together and (b) the
1668 IPv6 address comes first. This makes handling the messy features easier, and
1669 also simplifies the construction of the "daemon started" log line. */
1672 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
1674 ip_address_item *ipa2;
1676 /* Handle an IPv4 wildcard */
1678 if (ipa->address[0] == 0)
1679 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1681 ip_address_item *ipa3 = ipa2->next;
1682 if (ipa3->address[0] == ':' &&
1683 ipa3->address[1] == 0 &&
1684 ipa3->port == ipa->port)
1686 ipa2->next = ipa3->next;
1693 /* Handle an IPv6 wildcard. */
1695 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
1696 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1698 ip_address_item *ipa3 = ipa2->next;
1699 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1701 ipa2->next = ipa3->next;
1702 ipa3->next = ipa->next;
1710 /* Get a vector to remember all the sockets in.
1711 Two extra elements for the ancillary sockets */
1713 for (ipa = addresses; ipa; ipa = ipa->next)
1714 listen_socket_count++;
1715 fd_polls = store_get(sizeof(struct pollfd) * (listen_socket_count + 2),
1717 for (struct pollfd * p = fd_polls; p < fd_polls + listen_socket_count + 2;
1719 { p->fd = -1; p->events = POLLIN; }
1721 } /* daemon_listen but not inetd_wait_mode */
1723 if (f.daemon_listen)
1726 /* Do a sanity check on the max connects value just to save us from getting
1727 a huge amount of store. */
1729 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1731 /* There's no point setting smtp_accept_queue unless it is less than the max
1732 connects limit. The configuration reader ensures that the max is set if the
1733 queue-only option is set. */
1735 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1737 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1738 track of them for total number and queue/host limits. */
1740 if (smtp_accept_max > 0)
1742 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), GET_UNTAINTED);
1743 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
1747 /* The variable background_daemon is always false when debugging, but
1748 can also be forced false in order to keep a non-debugging daemon in the
1749 foreground. If background_daemon is true, close all open file descriptors that
1750 we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1751 do this for inetd_wait mode.
1753 This is protection against any called functions (in libraries, or in
1754 Perl, or whatever) that think they can write to stderr (or stdout). Before this
1755 was added, it was quite likely that an SMTP connection would use one of these
1756 file descriptors, in which case writing random stuff to it caused chaos.
1758 Then disconnect from the controlling terminal, Most modern Unixes seem to have
1759 setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1760 setsid() can be #defined as a no-op, or as something else. */
1762 if (f.background_daemon || f.inetd_wait_mode)
1764 log_close_all(); /* Just in case anything was logged earlier */
1765 search_tidyup(); /* Just in case any were used in reading the config. */
1766 (void)close(0); /* Get rid of stdin/stdout/stderr */
1769 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
1770 log_stderr = NULL; /* So no attempt to copy paniclog output */
1773 if (f.background_daemon)
1775 /* If the parent process of this one has pid == 1, we are re-initializing the
1776 daemon as the result of a SIGHUP. In this case, there is no need to do
1777 anything, because the controlling terminal has long gone. Otherwise, fork, in
1778 case current process is a process group leader (see 'man setsid' for an
1779 explanation) before calling setsid().
1780 All other forks want daemon_listen cleared. Rather than blow a register, jsut
1785 BOOL daemon_listen = f.daemon_listen;
1786 pid_t pid = exim_fork(US"daemon");
1787 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1788 "fork() failed when starting daemon: %s", strerror(errno));
1789 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1790 (void)setsid(); /* release controlling terminal */
1791 f.daemon_listen = daemon_listen;
1795 /* We are now in the disconnected, daemon process (unless debugging). Set up
1796 the listening sockets if required. */
1798 daemon_notifier_socket();
1800 if (f.daemon_listen && !f.inetd_wait_mode)
1803 ip_address_item *ipa;
1805 /* For each IP address, create a socket, bind it to the appropriate port, and
1806 start listening. See comments above about IPv6 sockets that may or may not
1807 accept IPv4 calls when listening on all interfaces. We also have to cope with
1808 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1809 listening, provided a wildcard IPv4 socket for the same port follows. */
1811 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1814 ip_address_item * ipa2;
1817 if (Ustrchr(ipa->address, ':') != NULL)
1820 wildcard = ipa->address[1] == 0;
1825 wildcard = ipa->address[0] == 0;
1828 if ((fd_polls[sk].fd = fd = ip_socket(SOCK_STREAM, af)) < 0)
1830 if (check_special_case(0, addresses, ipa, FALSE))
1832 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1833 "listening (%s): will use IPv4", strerror(errno));
1836 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1837 af == AF_INET6 ? '6' : '4', strerror(errno));
1840 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1841 available. Just log failure (can get protocol not available, just like
1842 socket creation can). */
1845 if (af == AF_INET6 && wildcard &&
1846 setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
1847 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1848 "socket failed (%s): carrying on without it", strerror(errno));
1849 #endif /* IPV6_V6ONLY */
1851 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1852 is being handled. Without this, a connection will prevent reuse of the
1853 smtp port for listening. */
1855 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0)
1856 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1857 "failed when starting daemon: %s", strerror(errno));
1859 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1860 disable this because it breaks some broken clients. */
1862 if (tcp_nodelay) setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on));
1864 /* Now bind the socket to the required port; if Exim is being restarted
1865 it may not always be possible to bind immediately, even with SO_REUSEADDR
1866 set, so try 10 times, waiting between each try. After 10 failures, we give
1867 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1868 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1869 address for the same port, ignore the error on the grounds that we must be
1870 in a system where the IPv6 socket accepts both kinds of call. This is
1871 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1872 listen() stage instead. */
1875 f.tcp_fastopen_ok = TRUE;
1880 if (ip_bind(fd, af, ipa->address, ipa->port) >= 0) break;
1881 if (check_special_case(errno, addresses, ipa, TRUE))
1883 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1884 "listen() success; EADDRINUSE ignored\n");
1888 msg = US strerror(errno);
1894 if (daemon_startup_retries <= 0)
1895 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1896 "socket bind() to port %d for address %s failed: %s: "
1897 "daemon abandoned", ipa->port, addr, msg);
1898 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
1899 "failed: %s: waiting %s before trying again (%d more %s)",
1900 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1901 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1902 daemon_startup_retries--;
1903 sleep(daemon_startup_sleep);
1908 debug_printf("listening on all interfaces (IPv%c) port %d\n",
1909 af == AF_INET6 ? '6' : '4', ipa->port);
1911 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
1913 /* Start listening on the bound socket, establishing the maximum backlog of
1914 connections that is allowed. On success, add to the set of sockets for select
1915 and continue to the next address. */
1917 #if defined(TCP_FASTOPEN) && !defined(__APPLE__)
1918 if ( f.tcp_fastopen_ok
1919 && setsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN,
1920 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
1922 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1923 f.tcp_fastopen_ok = FALSE;
1926 if (listen(fd, smtp_connect_backlog) >= 0)
1928 #if defined(TCP_FASTOPEN) && defined(__APPLE__)
1929 if ( f.tcp_fastopen_ok
1930 && setsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN, &on, sizeof(on)))
1932 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1933 f.tcp_fastopen_ok = FALSE;
1936 fd_polls[sk].fd = fd;
1940 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1941 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1942 and there was a previous successful IPv6 wildcard listen on the same port,
1943 we want to ignore the error on the grounds that we must be in a system
1944 where the IPv6 socket accepts both kinds of call. */
1946 if (!check_special_case(errno, addresses, ipa, TRUE))
1947 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
1949 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
1952 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1953 "listen() success; EADDRINUSE ignored\n");
1956 /* Come here if there has been a problem with the socket which we
1957 are going to ignore. We remove the address from the chain, and back up the
1961 sk--; /* Back up the count */
1962 listen_socket_count--; /* Reduce the total */
1963 if (ipa == addresses) addresses = ipa->next; else
1965 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1966 ipa2->next = ipa->next;
1969 } /* End of bind/listen loop for each address */
1970 } /* End of setup for listening */
1973 /* If we are not listening, we want to write a pid file only if -oP was
1974 explicitly given. */
1976 else if (!override_pid_file_path)
1979 /* Write the pid to a known file for assistance in identification, if required.
1980 We do this before giving up root privilege, because on some systems it is
1981 necessary to be root in order to write into the pid file directory. There's
1982 nothing to stop multiple daemons running, as long as no more than one listens
1983 on a given TCP/IP port on the same interface(s). However, in these
1984 circumstances it gets far too complicated to mess with pid file names
1985 automatically. Consequently, Exim 4 writes a pid file only
1987 (a) When running in the test harness, or
1988 (b) When -bd is used and -oX is not used, or
1989 (c) When -oP is used to supply a path.
1991 The variable daemon_write_pid is used to control this. */
1993 if (f.running_in_test_harness || write_pid)
1995 const enum pid_op operation = (f.running_in_test_harness
1996 || real_uid == root_uid
1997 || (real_uid == exim_uid && !override_pid_file_path)) ? PID_WRITE : PID_CHECK;
1998 if (!operate_on_pid_file(operation, getpid()))
1999 DEBUG(D_any) debug_printf("%s pid file %s: %s\n", (operation == PID_WRITE) ? "write" : "check", pid_file_path, strerror(errno));
2002 /* Set up the handler for SIGHUP, which causes a restart of the daemon. */
2004 sighup_seen = FALSE;
2005 signal(SIGHUP, sighup_handler);
2007 /* Give up root privilege at this point (assuming that exim_uid and exim_gid
2008 are not root). The third argument controls the running of initgroups().
2009 Normally we do this, in order to set up the groups for the Exim user. However,
2010 if we are not root at this time - some odd installations run that way - we
2013 exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
2015 /* Update the originator_xxx fields so that received messages as listed as
2016 coming from Exim, not whoever started the daemon. */
2018 originator_uid = exim_uid;
2019 originator_gid = exim_gid;
2020 originator_login = (pw = getpwuid(exim_uid))
2021 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
2023 /* Get somewhere to keep the list of queue-runner pids if we are keeping track
2024 of them (and also if we are doing queue runs). */
2026 if (queue_interval > 0 && local_queue_run_max > 0)
2028 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t), GET_UNTAINTED);
2029 for (int i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
2032 /* Set up the handler for termination of child processes, and the one
2033 telling us to die. */
2035 sigchld_seen = FALSE;
2036 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
2038 sigterm_seen = FALSE;
2039 os_non_restarting_signal(SIGTERM, main_sigterm_handler);
2040 os_non_restarting_signal(SIGINT, main_sigterm_handler);
2042 /* If we are to run the queue periodically, pretend the alarm has just gone
2043 off. This will cause the first queue-runner to get kicked off straight away. */
2045 sigalrm_seen = (queue_interval > 0);
2047 /* Log the start up of a daemon - at least one of listening or queue running
2050 if (f.inetd_wait_mode)
2052 uschar *p = big_buffer;
2054 if (inetd_wait_timeout >= 0)
2055 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
2057 sprintf(CS p, "with no wait timeout");
2059 log_write(0, LOG_MAIN,
2060 "exim %s daemon started: pid=%d, launched with listening socket, %s",
2061 version_string, getpid(), big_buffer);
2062 set_process_info("daemon(%s): pre-listening socket", version_string);
2064 /* set up the timeout logic */
2065 sigalrm_seen = TRUE;
2068 else if (f.daemon_listen)
2071 int smtps_ports = 0;
2072 ip_address_item * ipa;
2074 uschar * qinfo = queue_interval > 0
2075 ? string_sprintf("-q%s%s",
2076 f.queue_2stage ? "q" : "", readconf_printtime(queue_interval))
2077 : US"no queue runs";
2079 /* Build a list of listening addresses in big_buffer, but limit it to 10
2080 items. The style is for backwards compatibility.
2082 It is now possible to have some ports listening for SMTPS (the old,
2083 deprecated protocol that starts TLS without using STARTTLS), and others
2084 listening for standard SMTP. Keep their listings separate. */
2086 for (int j = 0, i; j < 2; j++)
2088 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
2090 /* First time round, look for SMTP ports; second time round, look for
2091 SMTPS ports. Build IP+port strings. */
2093 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
2100 /* Now the information about the port (and sometimes interface) */
2102 if (ipa->address[0] == ':' && ipa->address[1] == 0)
2104 if (ipa->next && ipa->next->address[0] == 0 &&
2105 ipa->next->port == ipa->port)
2107 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
2108 (ipa = ipa->next)->log = NULL;
2110 else if (ipa->v6_include_v4)
2111 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
2113 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
2115 else if (ipa->address[0] == 0) /* v4 wildcard */
2116 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
2117 else /* check for previously-seen IP */
2119 ip_address_item * i2;
2120 for (i2 = addresses; i2 != ipa; i2 = i2->next)
2121 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
2122 && Ustrcmp(ipa->address, i2->address) == 0
2124 { /* found; append port to list */
2125 for (p = i2->log; *p; ) p++; /* end of existing string */
2126 if (*--p == '}') *p = '\0'; /* drop EOL */
2127 while (isdigit(*--p)) ; /* char before port */
2129 i2->log = *p == ':' /* no list yet? { */
2130 ? string_sprintf("%.*s{%s,%d}",
2131 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
2132 : string_sprintf("%s,%d}", i2->log, ipa->port);
2136 if (i2 == ipa) /* first-time IP */
2137 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
2144 for (int j = 0, i; j < 2; j++)
2146 /* First time round, look for SMTP ports; second time round, look for
2147 SMTPS ports. For the first one of each, insert leading text. */
2152 p += sprintf(CS p, "SMTP on");
2155 if (smtps_ports > 0)
2156 p += sprintf(CS p, "%sSMTPS on",
2157 smtp_ports == 0 ? "" : " and for ");
2159 /* Now the information about the port (and sometimes interface) */
2161 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
2162 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
2164 p += sprintf(CS p, "%s", ipa->log);
2167 p += sprintf(CS p, " ...");
2170 log_write(0, LOG_MAIN,
2171 "exim %s daemon started: pid=%d, %s, listening for %s",
2172 version_string, getpid(), qinfo, big_buffer);
2173 set_process_info("daemon(%s): %s, listening for %s",
2174 version_string, qinfo, big_buffer);
2179 uschar * s = *queue_name
2180 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
2181 : string_sprintf("-q%s", readconf_printtime(queue_interval));
2182 log_write(0, LOG_MAIN,
2183 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
2184 version_string, getpid(), s);
2185 set_process_info("daemon(%s): %s, not listening", version_string, s);
2188 /* Do any work it might be useful to amortize over our children
2189 (eg: compile regex) */
2192 smtp_deliver_init(); /* Used for callouts */
2194 #ifndef DISABLE_DKIM
2196 # ifdef MEASURE_TIMING
2198 gettimeofday(&t0, NULL);
2201 # ifdef MEASURE_TIMING
2202 report_time_since(&t0, US"dkim_exim_init (delta)");
2207 #ifdef WITH_CONTENT_SCAN
2217 /* Add ancillary sockets to the set for select */
2219 poll_fd_count = listen_socket_count;
2221 if (tls_watch_fd >= 0)
2223 tls_watch_poll = &fd_polls[poll_fd_count++];
2224 tls_watch_poll->fd = tls_watch_fd;
2225 tls_watch_poll->events = POLLIN;
2228 if (daemon_notifier_fd >= 0)
2230 dnotify_poll = &fd_polls[poll_fd_count++];
2231 dnotify_poll->fd = daemon_notifier_fd;
2232 dnotify_poll->events = POLLIN;
2235 /* Close the log so it can be renamed and moved. In the few cases below where
2236 this long-running process writes to the log (always exceptional conditions), it
2237 closes the log afterwards, for the same reason. */
2241 DEBUG(D_any) debug_print_ids(US"daemon running with");
2243 /* Any messages accepted via this route are going to be SMTP. */
2247 #ifdef MEASURE_TIMING
2248 report_time_since(×tamp_startup, US"daemon loop start"); /* testcase 0022 */
2251 /* Enter the never-ending loop... */
2258 daemon_die(); /* Does not return */
2260 /* This code is placed first in the loop, so that it gets obeyed at the
2261 start, before the first wait, for the queue-runner case, so that the first
2262 one can be started immediately.
2264 The other option is that we have an inetd wait timeout specified to -bw. */
2268 if (inetd_wait_timeout > 0)
2270 time_t resignal_interval = inetd_wait_timeout;
2272 if (last_connection_time == (time_t)0)
2275 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
2279 time_t now = time(NULL);
2280 if (now == (time_t)-1)
2282 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
2286 if ((now - last_connection_time) >= inetd_wait_timeout)
2289 debug_printf("inetd wait timeout %d expired, ending daemon\n",
2290 inetd_wait_timeout);
2291 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
2297 resignal_interval -= (now - last_connection_time);
2302 sigalrm_seen = FALSE;
2303 ALARM(resignal_interval);
2308 DEBUG(D_any) debug_printf("%s received\n",
2309 #ifndef DISABLE_QUEUE_RAMP
2310 *queuerun_msgid ? "qrun notification" :
2314 /* Do a full queue run in a child process, if required, unless we already
2315 have enough queue runners on the go. If we are not running as root, a
2316 re-exec is required. */
2318 if ( queue_interval > 0
2319 && (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
2321 if ((pid = exim_fork(US"queue-runner")) == 0)
2323 /* Disable debugging if it's required only for the daemon process. We
2324 leave the above message, because it ties up with the "child ended"
2325 debugging messages. */
2327 if (f.debug_daemon) debug_selector = 0;
2329 /* Close any open listening sockets in the child */
2331 close_daemon_sockets(daemon_notifier_fd,
2332 fd_polls, listen_socket_count);
2334 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
2336 signal(SIGHUP, SIG_DFL);
2337 signal(SIGCHLD, SIG_DFL);
2338 signal(SIGTERM, SIG_DFL);
2339 signal(SIGINT, SIG_DFL);
2341 /* Re-exec if privilege has been given up, unless deliver_drop_
2342 privilege is set. Reset SIGALRM before exec(). */
2344 if (geteuid() != root_uid && !deliver_drop_privilege)
2351 signal(SIGALRM, SIG_DFL);
2355 #ifndef DISABLE_QUEUE_RAMP
2359 if (f.queue_run_first_delivery) *p++ = 'i';
2360 if (f.queue_run_force) *p++ = 'f';
2361 if (f.deliver_force_thaw) *p++ = 'f';
2362 if (f.queue_run_local) *p++ = 'l';
2364 extra[0] = *queue_name
2365 ? string_sprintf("%sG%s", opt, queue_name) : opt;
2367 #ifndef DISABLE_QUEUE_RAMP
2368 if (*queuerun_msgid)
2370 log_write(0, LOG_MAIN, "notify triggered queue run");
2371 extra[extracount++] = queuerun_msgid; /* Trigger only the */
2372 extra[extracount++] = queuerun_msgid; /* one message */
2376 /* If -R or -S were on the original command line, ensure they get
2379 if (deliver_selectstring)
2381 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
2382 extra[extracount++] = deliver_selectstring;
2385 if (deliver_selectstring_sender)
2387 extra[extracount++] = f.deliver_selectstring_sender_regex
2389 extra[extracount++] = deliver_selectstring_sender;
2392 /* Overlay this process with a new execution. */
2394 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
2395 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
2397 /* Control never returns here. */
2400 /* No need to re-exec; SIGALRM remains set to the default handler */
2402 #ifndef DISABLE_QUEUE_RAMP
2403 if (*queuerun_msgid)
2405 log_write(0, LOG_MAIN, "notify triggered queue run");
2406 f.queue_2stage = FALSE;
2407 queue_run(queuerun_msgid, queuerun_msgid, FALSE);
2411 queue_run(NULL, NULL, FALSE);
2412 exim_underbar_exit(EXIT_SUCCESS);
2417 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
2418 "process failed: %s", strerror(errno));
2423 for (int i = 0; i < local_queue_run_max; ++i)
2424 if (queue_pid_slots[i] <= 0)
2426 queue_pid_slots[i] = pid;
2430 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
2431 queue_run_count, queue_run_count == 1 ? "" : "es");
2435 /* Reset the alarm clock */
2437 sigalrm_seen = FALSE;
2438 #ifndef DISABLE_QUEUE_RAMP
2439 if (*queuerun_msgid)
2440 *queuerun_msgid = 0;
2443 ALARM(queue_interval);
2446 } /* sigalrm_seen */
2449 /* Sleep till a connection happens if listening, and handle the connection if
2450 that is why we woke up. The FreeBSD operating system requires the use of
2451 select() before accept() because the latter function is not interrupted by
2452 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2453 OS do notice signals in accept() but it does no harm to have the select()
2454 in for all of them - and it won't then be a lurking problem for ports to
2455 new OS. In fact, the later addition of listening on specific interfaces only
2456 requires this way of working anyway. */
2458 if (f.daemon_listen)
2461 BOOL select_failed = FALSE;
2463 DEBUG(D_any) debug_printf("Listening...\n");
2465 /* In rare cases we may have had a SIGCHLD signal in the time between
2466 setting the handler (below) and getting back here. If so, pretend that the
2467 select() was interrupted so that we reap the child. This might still leave
2468 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
2469 only to do the reaping more quickly, it shouldn't result in anything other
2470 than a delay until something else causes a wake-up. */
2478 lcount = poll(fd_polls, poll_fd_count, -1);
2482 select_failed = TRUE;
2486 /* Clean up any subprocesses that may have terminated. We need to do this
2487 here so that smtp_accept_max_per_host works when a connection to that host
2488 has completed, and we are about to accept a new one. When this code was
2489 later in the sequence, a new connection could be rejected, even though an
2490 old one had just finished. Preserve the errno from any select() failure for
2491 the use of the common select/accept error processing below. */
2494 int select_errno = errno;
2495 handle_ending_processes();
2500 /* Create or rotate any required keys; handle (delayed) filewatch event */
2502 if ((old_tfd = tls_daemon_tick()) >= 0)
2503 for (struct pollfd * p = &fd_polls[listen_socket_count];
2504 p < fd_polls + poll_fd_count; p++)
2505 if (p->fd == old_tfd) { p->fd = tls_watch_fd ; break; }
2508 errno = select_errno;
2511 /* Loop for all the sockets that are currently ready to go. If select
2512 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2513 to use the common error code for select/accept below. */
2515 while (lcount-- > 0)
2517 int accept_socket = -1;
2519 struct sockaddr_in6 accepted;
2521 struct sockaddr_in accepted;
2526 #if !defined(DISABLE_TLS) && (defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT))
2527 if (tls_watch_poll && tls_watch_poll->revents & POLLIN)
2529 tls_watch_poll->revents = 0;
2530 tls_watch_trigger_time = time(NULL); /* Set up delayed event */
2531 tls_watch_discard_event(tls_watch_fd);
2532 break; /* to top of daemon loop */
2535 if (dnotify_poll && dnotify_poll->revents & POLLIN)
2537 dnotify_poll->revents = 0;
2538 sigalrm_seen = daemon_notification();
2539 break; /* to top of daemon loop */
2541 for (struct pollfd * p = fd_polls; p < fd_polls + listen_socket_count;
2543 if (p->revents & POLLIN)
2545 EXIM_SOCKLEN_T alen = sizeof(accepted);
2548 socklen_t tlen = sizeof(ti);
2550 /* If monitoring the backlog is wanted, grab for later logging */
2552 smtp_listen_backlog = 0;
2553 if ( smtp_backlog_monitor > 0
2554 && getsockopt(p->fd, IPPROTO_TCP, TCP_INFO, &ti, &tlen) == 0)
2556 # ifdef EXIM_HAVE_TCPI_UNACKED
2557 DEBUG(D_interface) debug_printf("listen fd %d queue max %u curr %u\n",
2558 p->fd, ti.tcpi_sacked, ti.tcpi_unacked);
2559 smtp_listen_backlog = ti.tcpi_unacked;
2560 # elif defined(__FreeBSD__) /* This does not work. Investigate kernel sourcecode. */
2561 DEBUG(D_interface) debug_printf("listen fd %d queue max %u curr %u\n",
2562 p->fd, ti.__tcpi_sacked, ti.__tcpi_unacked);
2563 smtp_listen_backlog = ti.__tcpi_unacked;
2568 accept_socket = accept(p->fd, (struct sockaddr *)&accepted, &alen);
2573 /* If select or accept has failed and this was not caused by an
2574 interruption, log the incident and try again. With asymmetric TCP/IP
2575 routing errors such as "No route to network" have been seen here. Also
2576 "connection reset by peer" has been seen. These cannot be classed as
2577 disastrous errors, but they could fill up a lot of log. The code in smail
2578 crashes the daemon after 10 successive failures of accept, on the grounds
2579 that some OS fail continuously. Exim originally followed suit, but this
2580 appears to have caused problems. Now it just keeps going, but instead of
2581 logging each error, it batches them up when they are continuous. */
2583 if (accept_socket < 0 && errno != EINTR)
2585 if (accept_retry_count == 0)
2587 accept_retry_errno = errno;
2588 accept_retry_select_failed = select_failed;
2590 else if ( errno != accept_retry_errno
2591 || select_failed != accept_retry_select_failed
2592 || accept_retry_count >= 50)
2594 log_write(0, LOG_MAIN | (accept_retry_count >= 50 ? LOG_PANIC : 0),
2595 "%d %s() failure%s: %s",
2597 accept_retry_select_failed ? "select" : "accept",
2598 accept_retry_count == 1 ? "" : "s",
2599 strerror(accept_retry_errno));
2601 accept_retry_count = 0;
2602 accept_retry_errno = errno;
2603 accept_retry_select_failed = select_failed;
2605 accept_retry_count++;
2607 else if (accept_retry_count > 0)
2609 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2611 accept_retry_select_failed ? "select" : "accept",
2612 accept_retry_count == 1 ? "" : "s",
2613 strerror(accept_retry_errno));
2615 accept_retry_count = 0;
2618 /* If select/accept succeeded, deal with the connection. */
2620 if (accept_socket >= 0)
2622 #ifdef TCP_QUICKACK /* Avoid pure-ACKs while in tls protocol pingpong phase */
2623 /* Unfortunately we cannot be certain to do this before a TLS-on-connect
2624 Client Hello arrives and is acked. We do it as early as possible. */
2625 (void) setsockopt(accept_socket, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
2627 if (inetd_wait_timeout)
2628 last_connection_time = time(NULL);
2629 handle_smtp_call(fd_polls, listen_socket_count, accept_socket,
2630 (struct sockaddr *)&accepted);
2635 /* If not listening, then just sleep for the queue interval. If we woke
2636 up early the last time for some other signal, it won't matter because
2637 the alarm signal will wake at the right time. This code originally used
2638 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2639 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2640 select() can be used as an interruptible sleep() on all versions of Unix. */
2645 poll(&p, 0, queue_interval * 1000);
2646 handle_ending_processes();
2649 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2650 for itself, because it isn't doing the waiting itself. */
2654 sigchld_seen = FALSE;
2655 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
2658 /* Handle being woken by SIGHUP. We know at this point that the result
2659 of accept() has been dealt with, so we can re-exec exim safely, first
2660 closing the listening sockets so that they can be reused. Cancel any pending
2661 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2662 that another HUP in quick succession doesn't clobber the new daemon before it
2663 gets going. All log files get closed by the close-on-exec flag; however, if
2664 the exec fails, we need to close the logs. */
2668 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2670 close_daemon_sockets(daemon_notifier_fd, fd_polls, listen_socket_count);
2672 signal(SIGHUP, SIG_IGN);
2673 sighup_argv[0] = exim_path;
2675 execv(CS exim_path, (char *const *)sighup_argv);
2676 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2677 getpid(), exim_path, strerror(errno));
2681 } /* End of main loop */
2683 /* Control never reaches here */
2688 /* End of exim_daemon.c */