1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim Maintainers 2020 */
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 damon pif 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 int * listen_sockets, 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(listen_sockets[i]);
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 listen_sockets 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(int *listen_sockets, 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 == NULL && 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 != NULL && 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 /* May have been modified for the subprocess */
407 *log_selector = save_log_selector;
409 /* Get the local interface address into permanent store */
411 store_pool = POOL_PERM;
412 interface_address = string_copy(interface_address);
413 store_pool = old_pool;
415 /* Check for a tls-on-connect port */
417 if (host_is_tls_on_connect_port(interface_port)) tls_in.on_connect = TRUE;
419 /* Expand smtp_active_hostname if required. We do not do this any earlier,
420 because it may depend on the local interface address (indeed, that is most
421 likely what it depends on.) */
423 smtp_active_hostname = primary_hostname;
424 if (raw_active_hostname)
426 uschar * nah = expand_string(raw_active_hostname);
429 if (!f.expand_string_forcedfail)
431 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand \"%s\" "
432 "(smtp_active_hostname): %s", raw_active_hostname,
433 expand_string_message);
434 smtp_printf("421 Local configuration error; "
435 "please try again later.\r\n", FALSE);
438 exim_underbar_exit(EXIT_FAILURE);
441 else if (*nah) smtp_active_hostname = nah;
444 /* Initialize the queueing flags */
447 session_local_queue_only = queue_only;
449 /* Close the listening sockets, and set the SIGCHLD handler to SIG_IGN.
450 We also attempt to set things up so that children are automatically reaped,
451 but just in case this isn't available, there's a paranoid waitpid() in the
452 loop too (except for systems where we are sure it isn't needed). See the more
453 extensive comment before the reception loop in exim.c for a fuller
454 explanation of this logic. */
456 close_daemon_sockets(daemon_notifier_fd, listen_sockets, listen_socket_count);
458 /* Set FD_CLOEXEC on the SMTP socket. We don't want any rogue child processes
459 to be able to communicate with them, under any circumstances. */
460 (void)fcntl(accept_socket, F_SETFD,
461 fcntl(accept_socket, F_GETFD) | FD_CLOEXEC);
462 (void)fcntl(dup_accept_socket, F_SETFD,
463 fcntl(dup_accept_socket, F_GETFD) | FD_CLOEXEC);
466 act.sa_handler = SIG_IGN;
467 sigemptyset(&(act.sa_mask));
468 act.sa_flags = SA_NOCLDWAIT;
469 sigaction(SIGCHLD, &act, NULL);
471 signal(SIGCHLD, SIG_IGN);
473 signal(SIGTERM, SIG_DFL);
474 signal(SIGINT, SIG_DFL);
476 /* Attempt to get an id from the sending machine via the RFC 1413
477 protocol. We do this in the sub-process in order not to hold up the
478 main process if there is any delay. Then set up the fullhost information
479 in case there is no HELO/EHLO.
481 If debugging is enabled only for the daemon, we must turn if off while
482 finding the id, but turn it on again afterwards so that information about the
483 incoming connection is output. */
485 if (f.debug_daemon) debug_selector = 0;
486 verify_get_ident(IDENT_PORT);
487 host_build_sender_fullhost();
488 debug_selector = save_debug_selector;
491 debug_printf("Process %d is handling incoming connection from %s\n",
492 (int)getpid(), sender_fullhost);
494 /* Now disable debugging permanently if it's required only for the daemon
497 if (f.debug_daemon) debug_selector = 0;
499 /* If there are too many child processes for immediate delivery,
500 set the session_local_queue_only flag, which is initialized from the
501 configured value and may therefore already be TRUE. Leave logging
502 till later so it will have a message id attached. Note that there is no
503 possibility of re-calculating this per-message, because the value of
504 smtp_accept_count does not change in this subprocess. */
506 if (smtp_accept_queue > 0 && smtp_accept_count > smtp_accept_queue)
508 session_local_queue_only = TRUE;
509 queue_only_reason = 1;
512 /* Handle the start of the SMTP session, then loop, accepting incoming
513 messages from the SMTP connection. The end will come at the QUIT command,
514 when smtp_setup_msg() returns 0. A break in the connection causes the
515 process to die (see accept.c).
517 NOTE: We do *not* call smtp_log_no_mail() if smtp_start_session() fails,
518 because a log line has already been written for all its failure exists
519 (usually "connection refused: <reason>") and writing another one is
520 unnecessary clutter. */
522 if (!smtp_start_session())
526 exim_underbar_exit(EXIT_SUCCESS);
532 message_id[0] = 0; /* Clear out any previous message_id */
533 reset_point = store_mark(); /* Save current store high water point */
536 debug_printf("Process %d is ready for new message\n", (int)getpid());
538 /* Smtp_setup_msg() returns 0 on QUIT or if the call is from an
539 unacceptable host or if an ACL "drop" command was triggered, -1 on
540 connection lost, and +1 on validly reaching DATA. Receive_msg() almost
541 always returns TRUE when smtp_input is true; just retry if no message was
542 accepted (can happen for invalid message parameters). However, it can yield
543 FALSE if the connection was forcibly dropped by the DATA ACL. */
545 if ((rc = smtp_setup_msg()) > 0)
547 BOOL ok = receive_msg(FALSE);
548 search_tidyup(); /* Close cached databases */
549 if (!ok) /* Connection was dropped */
551 cancel_cutthrough_connection(TRUE, US"receive dropped");
553 smtp_log_no_mail(); /* Log no mail if configured */
554 exim_underbar_exit(EXIT_SUCCESS);
556 if (message_id[0] == 0) continue; /* No message was accepted */
558 else /* bad smtp_setup_msg() */
562 int fd = fileno(smtp_in);
566 /* drain socket, for clean TCP FINs */
567 if (fcntl(fd, F_SETFL, O_NONBLOCK) == 0)
568 for(int i = 16; read(fd, buf, sizeof(buf)) > 0 && i > 0; ) i--;
570 cancel_cutthrough_connection(TRUE, US"message setup dropped");
572 smtp_log_no_mail(); /* Log no mail if configured */
574 /*XXX should we pause briefly, hoping that the client will be the
575 active TCP closer hence get the TCP_WAIT endpoint? */
576 DEBUG(D_receive) debug_printf("SMTP>>(close on process exit)\n");
577 exim_underbar_exit(rc ? EXIT_FAILURE : EXIT_SUCCESS);
580 /* Show the recipients when debugging */
585 debug_printf("Sender: %s\n", sender_address);
588 debug_printf("Recipients:\n");
589 for (int i = 0; i < recipients_count; i++)
590 debug_printf(" %s\n", recipients_list[i].address);
594 /* A message has been accepted. Clean up any previous delivery processes
595 that have completed and are defunct, on systems where they don't go away
596 by themselves (see comments when setting SIG_IGN above). On such systems
597 (if any) these delivery processes hang around after termination until
598 the next message is received. */
600 #ifndef SIG_IGN_WORKS
601 while (waitpid(-1, NULL, WNOHANG) > 0);
604 /* Reclaim up the store used in accepting this message */
607 int r = receive_messagecount;
608 BOOL q = f.queue_only_policy;
609 smtp_reset(reset_point);
611 f.queue_only_policy = q;
612 receive_messagecount = r;
615 /* If queue_only is set or if there are too many incoming connections in
616 existence, session_local_queue_only will be TRUE. If it is not, check
617 whether we have received too many messages in this session for immediate
620 if (!session_local_queue_only &&
621 smtp_accept_queue_per_connection > 0 &&
622 receive_messagecount > smtp_accept_queue_per_connection)
624 session_local_queue_only = TRUE;
625 queue_only_reason = 2;
628 /* Initialize local_queue_only from session_local_queue_only. If it is not
629 true, and queue_only_load is set, check that the load average is below it.
630 If local_queue_only is set by this means, we also set if for the session if
631 queue_only_load_latch is true (the default). This means that, once set,
632 local_queue_only remains set for any subsequent messages on the same SMTP
633 connection. This is a deliberate choice; even though the load average may
634 fall, it doesn't seem right to deliver later messages on the same call when
635 not delivering earlier ones. However, the are special circumstances such as
636 very long-lived connections from scanning appliances where this is not the
637 best strategy. In such cases, queue_only_load_latch should be set false. */
639 if ( !(local_queue_only = session_local_queue_only)
640 && queue_only_load >= 0
641 && (local_queue_only = (load_average = OS_GETLOADAVG()) > queue_only_load)
644 queue_only_reason = 3;
645 if (queue_only_load_latch) session_local_queue_only = TRUE;
648 /* Log the queueing here, when it will get a message id attached, but
649 not if queue_only is set (case 0). */
651 if (local_queue_only) switch(queue_only_reason)
653 case 1: log_write(L_delay_delivery,
654 LOG_MAIN, "no immediate delivery: too many connections "
655 "(%d, max %d)", smtp_accept_count, smtp_accept_queue);
658 case 2: log_write(L_delay_delivery,
659 LOG_MAIN, "no immediate delivery: more than %d messages "
660 "received in one connection", smtp_accept_queue_per_connection);
663 case 3: log_write(L_delay_delivery,
664 LOG_MAIN, "no immediate delivery: load average %.2f",
665 (double)load_average/1000.0);
669 /* If a delivery attempt is required, spin off a new process to handle it.
670 If we are not root, we have to re-exec exim unless deliveries are being
671 done unprivileged. */
673 else if ( (!f.queue_only_policy || f.queue_smtp)
674 && !f.deliver_freeze)
678 /* We used to flush smtp_out before forking so that buffered data was not
679 duplicated, but now we want to pipeline the responses for data and quit.
680 Instead, hard-close the fd underlying smtp_out right after fork to discard
683 if ((dpid = exim_fork(US"daemon-accept-delivery")) == 0)
685 (void)fclose(smtp_in);
686 (void)close(fileno(smtp_out));
687 (void)fclose(smtp_out);
689 /* Don't ever molest the parent's SSL connection, but do clean up
690 the data structures if necessary. */
693 tls_close(NULL, TLS_NO_SHUTDOWN);
696 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
698 signal(SIGHUP, SIG_DFL);
699 signal(SIGCHLD, SIG_DFL);
700 signal(SIGTERM, SIG_DFL);
701 signal(SIGINT, SIG_DFL);
703 if (geteuid() != root_uid && !deliver_drop_privilege)
705 signal(SIGALRM, SIG_DFL);
706 delivery_re_exec(CEE_EXEC_PANIC);
707 /* Control does not return here. */
710 /* No need to re-exec; SIGALRM remains set to the default handler */
712 (void) deliver_message(message_id, FALSE, FALSE);
714 exim_underbar_exit(EXIT_SUCCESS);
719 release_cutthrough_connection(US"passed for delivery");
720 DEBUG(D_any) debug_printf("forked delivery process %d\n", (int)dpid);
724 cancel_cutthrough_connection(TRUE, US"delivery fork failed");
725 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: delivery process fork "
726 "failed: %s", strerror(errno));
733 /* Carrying on in the parent daemon process... Can't do much if the fork
734 failed. Otherwise, keep count of the number of accepting processes and
735 remember the pid for ticking off when the child completes. */
738 never_error(US"daemon: accept process fork failed", US"Fork failed", errno);
741 for (int i = 0; i < smtp_accept_max; ++i)
742 if (smtp_slots[i].pid <= 0)
744 smtp_slots[i].pid = pid;
745 /* Connection closes come asyncronously, so we cannot stack this store */
746 if (smtp_accept_max_per_host)
747 smtp_slots[i].host_address = string_copy_malloc(sender_host_address);
751 DEBUG(D_any) debug_printf("%d SMTP accept process%s running\n",
752 smtp_accept_count, smtp_accept_count == 1 ? "" : "es");
755 /* Get here via goto in error cases */
759 /* Close the streams associated with the socket which will also close the
760 socket fds in this process. We can't do anything if fclose() fails, but
761 logging brings it to someone's attention. However, "connection reset by peer"
762 isn't really a problem, so skip that one. On Solaris, a dropped connection can
763 manifest itself as a broken pipe, so drop that one too. If the streams don't
764 exist, something went wrong while setting things up. Make sure the socket
765 descriptors are closed, in order to drop the connection. */
769 if (fclose(smtp_out) != 0 && errno != ECONNRESET && errno != EPIPE)
770 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_out) failed: %s",
774 else (void)close(accept_socket);
778 if (fclose(smtp_in) != 0 && errno != ECONNRESET && errno != EPIPE)
779 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_in) failed: %s",
783 else (void)close(dup_accept_socket);
785 /* Release any store used in this process, including the store used for holding
786 the incoming host address and an expanded active_hostname. */
790 sender_host_address = NULL;
791 store_reset(reset_point);
792 sender_host_address = NULL;
798 /*************************************************
799 * Check wildcard listen special cases *
800 *************************************************/
802 /* This function is used when binding and listening on lists of addresses and
803 ports. It tests for special cases of wildcard listening, when IPv4 and IPv6
804 sockets may interact in different ways in different operating systems. It is
805 passed an error number, the list of listening addresses, and the current
806 address. Two checks are available: for a previous wildcard IPv6 address, or for
807 a following wildcard IPv4 address, in both cases on the same port.
809 In practice, pairs of wildcard addresses should be adjacent in the address list
810 because they are sorted that way below.
814 addresses the list of addresses
815 ipa the current IP address
816 back if TRUE, check for previous wildcard IPv6 address
817 if FALSE, check for a following wildcard IPv4 address
819 Returns: TRUE or FALSE
823 check_special_case(int eno, ip_address_item *addresses, ip_address_item *ipa,
826 ip_address_item *ipa2;
828 /* For the "back" case, if the failure was "address in use" for a wildcard IPv4
829 address, seek a previous IPv6 wildcard address on the same port. As it is
830 previous, it must have been successfully bound and be listening. Flag it as a
831 "6 including 4" listener. */
835 if (eno != EADDRINUSE || ipa->address[0] != 0) return FALSE;
836 for (ipa2 = addresses; ipa2 != ipa; ipa2 = ipa2->next)
838 if (ipa2->address[1] == 0 && ipa2->port == ipa->port)
840 ipa2->v6_include_v4 = TRUE;
846 /* For the "forward" case, if the current address is a wildcard IPv6 address,
847 we seek a following wildcard IPv4 address on the same port. */
851 if (ipa->address[0] != ':' || ipa->address[1] != 0) return FALSE;
852 for (ipa2 = ipa->next; ipa2 != NULL; ipa2 = ipa2->next)
853 if (ipa2->address[0] == 0 && ipa->port == ipa2->port) return TRUE;
862 /*************************************************
863 * Handle terminating subprocesses *
864 *************************************************/
866 /* Handle the termination of child processes. Theoretically, this need be done
867 only when sigchld_seen is TRUE, but rumour has it that some systems lose
868 SIGCHLD signals at busy times, so to be on the safe side, this function is
869 called each time round. It shouldn't be too expensive.
876 handle_ending_processes(void)
881 while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
885 debug_printf("child %d ended: status=0x%x\n", (int)pid, status);
887 if (WIFEXITED(status))
888 debug_printf(" normal exit, %d\n", WEXITSTATUS(status));
889 else if (WIFSIGNALED(status))
890 debug_printf(" signal exit, signal %d%s\n", WTERMSIG(status),
891 WCOREDUMP(status) ? " (core dumped)" : "");
895 /* If it's a listening daemon for which we are keeping track of individual
896 subprocesses, deal with an accepting process that has terminated. */
901 for (i = 0; i < smtp_accept_max; i++)
902 if (smtp_slots[i].pid == pid)
904 if (smtp_slots[i].host_address)
905 store_free(smtp_slots[i].host_address);
906 smtp_slots[i] = empty_smtp_slot;
907 if (--smtp_accept_count < 0) smtp_accept_count = 0;
908 DEBUG(D_any) debug_printf("%d SMTP accept process%s now running\n",
909 smtp_accept_count, (smtp_accept_count == 1)? "" : "es");
912 if (i < smtp_accept_max) continue; /* Found an accepting process */
915 /* If it wasn't an accepting process, see if it was a queue-runner
916 process that we are tracking. */
920 int max = atoi(CS expand_string(queue_run_max));
921 for (int i = 0; i < max; i++)
922 if (queue_pid_slots[i] == pid)
924 queue_pid_slots[i] = 0;
925 if (--queue_run_count < 0) queue_run_count = 0;
926 DEBUG(D_any) debug_printf("%d queue-runner process%s now running\n",
927 queue_run_count, (queue_run_count == 1)? "" : "es");
936 set_pid_file_path(void)
938 if (override_pid_file_path)
939 pid_file_path = override_pid_file_path;
942 pid_file_path = string_sprintf("%s/exim-daemon.pid", spool_directory);
944 if (pid_file_path[0] != '/')
945 log_write(0, LOG_PANIC_DIE, "pid file path %s must be absolute\n", pid_file_path);
949 enum pid_op { PID_WRITE, PID_CHECK, PID_DELETE };
951 /* Do various pid file operations as safe as possible. Ideally we'd just
952 drop the privileges for creation of the pid file and not care at all about removal of
954 Returns: true on success, false + errno==EACCES otherwise
958 operate_on_pid_file(const enum pid_op operation, const pid_t pid)
960 char pid_line[sizeof(int) * 3 + 2];
961 const int pid_len = snprintf(pid_line, sizeof(pid_line), "%d\n", (int)pid);
962 BOOL lines_match = FALSE;
963 uschar * path, * base, * dir;
965 const int dir_flags = O_RDONLY | O_NONBLOCK;
966 const int base_flags = O_NOFOLLOW | O_NONBLOCK;
967 const mode_t base_mode = 0644;
969 int cwd_fd, dir_fd, base_fd;
970 BOOL success = FALSE;
974 if (!f.running_in_test_harness && real_uid != root_uid && real_uid != exim_uid) goto cleanup;
975 if (pid_len < 2 || pid_len >= (int)sizeof(pid_line)) goto cleanup;
977 path = string_copy(pid_file_path);
978 if ((base = Ustrrchr(path, '/')) == NULL) /* should not happen, but who knows */
979 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid file path \"%s\" does not contain a '/'", pid_file_path);
981 dir = base != path ? path : US"/";
984 if (!dir || !*dir || *dir != '/') goto cleanup;
985 if (!base || !*base || Ustrchr(base, '/') != NULL) goto cleanup;
987 cwd_fd = open(".", dir_flags);
988 if (cwd_fd < 0 || fstat(cwd_fd, &sb) != 0 || !S_ISDIR(sb.st_mode)) goto cleanup;
989 dir_fd = open(CS dir, dir_flags);
990 if (dir_fd < 0 || fstat(dir_fd, &sb) != 0 || !S_ISDIR(sb.st_mode)) goto cleanup;
993 if (fchdir(dir_fd) != 0) goto cleanup;
994 base_fd = open(CS base, O_RDONLY | base_flags);
995 if (fchdir(cwd_fd) != 0)
996 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1000 char line[sizeof(pid_line)];
1003 if (fstat(base_fd, &sb) != 0 || !S_ISREG(sb.st_mode)) goto cleanup;
1004 if ((sb.st_mode & 07777) != base_mode || sb.st_nlink != 1) goto cleanup;
1005 if (sb.st_size < 2 || sb.st_size >= (off_t)sizeof(line)) goto cleanup;
1007 len = read(base_fd, line, sizeof(line));
1008 if (len != (ssize_t)sb.st_size) goto cleanup;
1011 if (strspn(line, "0123456789") != (size_t)len-1) goto cleanup;
1012 if (line[len-1] != '\n') goto cleanup;
1013 lines_match = len == pid_len && strcmp(line, pid_line) == 0;
1016 if (operation == PID_WRITE)
1023 /* emulate unlinkat */
1024 if (fchdir(dir_fd) != 0) goto cleanup;
1025 error = unlink(CS base);
1026 if (fchdir(cwd_fd) != 0)
1027 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1028 if (error) goto cleanup;
1029 (void)close(base_fd);
1032 /* emulate openat */
1033 if (fchdir(dir_fd) != 0) goto cleanup;
1034 base_fd = open(CS base, O_WRONLY | O_CREAT | O_EXCL | base_flags, base_mode);
1035 if (fchdir(cwd_fd) != 0)
1036 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1037 if (base_fd < 0) goto cleanup;
1038 if (fchmod(base_fd, base_mode) != 0) goto cleanup;
1039 if (write(base_fd, pid_line, pid_len) != pid_len) goto cleanup;
1040 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1045 if (!lines_match) goto cleanup;
1046 if (operation == PID_DELETE)
1049 /* emulate unlinkat */
1050 if (fchdir(dir_fd) != 0) goto cleanup;
1051 error = unlink(CS base);
1052 if (fchdir(cwd_fd) != 0)
1053 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1054 if (error) goto cleanup;
1062 if (cwd_fd >= 0) (void)close(cwd_fd);
1063 if (dir_fd >= 0) (void)close(dir_fd);
1064 if (base_fd >= 0) (void)close(base_fd);
1069 /* Remove the daemon's pidfile. Note: runs with root privilege,
1070 as a direct child of the daemon. Does not return. */
1073 delete_pid_file(void)
1075 const BOOL success = operate_on_pid_file(PID_DELETE, getppid());
1078 debug_printf("delete pid file %s %s: %s\n", pid_file_path,
1079 success ? "success" : "failure", strerror(errno));
1081 exim_exit(EXIT_SUCCESS);
1085 /* Called by the daemon; exec a child to get the pid file deleted
1086 since we may require privs for the containing directory */
1093 DEBUG(D_any) debug_printf("SIGTERM/SIGINT seen\n");
1094 #if !defined(DISABLE_TLS) && (defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT))
1095 tls_watch_invalidate();
1098 if (daemon_notifier_fd >= 0)
1100 close(daemon_notifier_fd);
1101 daemon_notifier_fd = -1;
1102 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1103 unlink_notifier_socket();
1107 if (f.running_in_test_harness || write_pid)
1109 if ((pid = exim_fork(US"daemon-del-pidfile")) == 0)
1111 if (override_pid_file_path)
1112 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 3,
1113 "-oP", override_pid_file_path, "-oPX");
1115 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 1, "-oPX");
1117 /* Control never returns here. */
1120 child_close(pid, 1);
1122 exim_exit(EXIT_SUCCESS);
1126 /*************************************************
1127 * Listener socket for local work prompts *
1128 *************************************************/
1131 daemon_notifier_socket(void)
1134 const uschar * where;
1135 struct sockaddr_un sa_un = {.sun_family = AF_UNIX};
1138 if (!notifier_socket || !*notifier_socket)
1140 DEBUG(D_any) debug_printf("-oY used so not creating notifier socket\n");
1143 if (override_local_interfaces && !override_pid_file_path)
1146 debug_printf("-oX used without -oP so not creating notifier socket\n");
1150 DEBUG(D_any) debug_printf("creating notifier socket\n");
1153 if ((fd = socket(PF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0)
1154 { where = US"socket"; goto bad; }
1156 if ((fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0)
1157 { where = US"socket"; goto bad; }
1158 (void)fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
1161 #ifdef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1162 sa_un.sun_path[0] = 0; /* Abstract local socket addr - Linux-specific? */
1163 len = offsetof(struct sockaddr_un, sun_path) + 1
1164 + snprintf(sa_un.sun_path+1, sizeof(sa_un.sun_path)-1, "%s",
1165 expand_string(notifier_socket));
1166 DEBUG(D_any) debug_printf(" @%s\n", sa_un.sun_path+1);
1167 #else /* filesystem-visible and persistent; will neeed removal */
1168 len = offsetof(struct sockaddr_un, sun_path)
1169 + snprintf(sa_un.sun_path, sizeof(sa_un.sun_path), "%s",
1170 expand_string(notifier_socket));
1171 DEBUG(D_any) debug_printf(" %s\n", sa_un.sun_path);
1174 if (bind(fd, (const struct sockaddr *)&sa_un, len) < 0)
1175 { where = US"bind"; goto bad; }
1177 #ifdef SO_PASSCRED /* Linux */
1178 if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0)
1179 { where = US"SO_PASSCRED"; goto bad2; }
1180 #elif defined(LOCAL_CREDS) /* FreeBSD-ish */
1181 if (setsockopt(fd, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
1182 { where = US"LOCAL_CREDS"; goto bad2; }
1185 /* debug_printf("%s: fd %d\n", __FUNCTION__, fd); */
1186 daemon_notifier_fd = fd;
1190 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1191 Uunlink(sa_un.sun_path);
1194 log_write(0, LOG_MAIN|LOG_PANIC, "%s %s: %s",
1195 __FUNCTION__, where, strerror(errno));
1201 static uschar queuerun_msgid[MESSAGE_ID_LENGTH+1];
1203 /* Return TRUE if a sigalrm should be emulated */
1205 daemon_notification(void)
1207 uschar buf[256], cbuf[256];
1208 struct sockaddr_un sa_un;
1209 struct iovec iov = {.iov_base = buf, .iov_len = sizeof(buf)-1};
1210 struct msghdr msg = { .msg_name = &sa_un,
1211 .msg_namelen = sizeof(sa_un),
1214 .msg_control = cbuf,
1215 .msg_controllen = sizeof(cbuf)
1219 buf[sizeof(buf)-1] = 0;
1220 if ((sz = recvmsg(daemon_notifier_fd, &msg, 0)) <= 0) return FALSE;
1221 if (sz >= sizeof(buf)) return FALSE;
1224 debug_printf("addrlen %d\n", msg.msg_namelen);
1226 DEBUG(D_queue_run) debug_printf("%s from addr '%s%.*s'\n", __FUNCTION__,
1227 *sa_un.sun_path ? "" : "@",
1228 (int)msg.msg_namelen - (*sa_un.sun_path ? 0 : 1),
1229 sa_un.sun_path + (*sa_un.sun_path ? 0 : 1));
1231 /* Refuse to handle the item unless the peer has good credentials */
1232 #ifdef SCM_CREDENTIALS
1233 # define EXIM_SCM_CR_TYPE SCM_CREDENTIALS
1234 #elif defined(LOCAL_CREDS) && defined(SCM_CREDS)
1235 # define EXIM_SCM_CR_TYPE SCM_CREDS
1237 /* The OS has no way to get the creds of the caller (for a unix/datagram socket.
1238 Punt; don't try to check. */
1241 #ifdef EXIM_SCM_CR_TYPE
1242 for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg);
1244 cp = CMSG_NXTHDR(&msg, cp))
1245 if (cp->cmsg_level == SOL_SOCKET && cp->cmsg_type == EXIM_SCM_CR_TYPE)
1247 # ifdef SCM_CREDENTIALS /* Linux */
1248 struct ucred * cr = (struct ucred *) CMSG_DATA(cp);
1249 if (cr->uid && cr->uid != exim_uid)
1251 DEBUG(D_queue_run) debug_printf("%s: sender creds pid %d uid %d gid %d\n",
1252 __FUNCTION__, (int)cr->pid, (int)cr->uid, (int)cr->gid);
1255 # elif defined(LOCAL_CREDS) /* BSD-ish */
1256 struct sockcred * cr = (struct sockcred *) CMSG_DATA(cp);
1257 if (cr->sc_uid && cr->sc_uid != exim_uid)
1259 DEBUG(D_queue_run) debug_printf("%s: sender creds pid ??? uid %d gid %d\n",
1260 __FUNCTION__, (int)cr->sc_uid, (int)cr->sc_gid);
1271 #ifndef DISABLE_QUEUE_RAMP
1272 case NOTIFY_MSG_QRUN:
1273 /* this should be a message_id */
1275 debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1);
1276 memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1);
1280 case NOTIFY_QUEUE_SIZE_REQ:
1283 int len = snprintf(CS buf, sizeof(buf), "%u", queue_count_cached());
1286 debug_printf("%s: queue size request: %s\n", __FUNCTION__, buf);
1288 if (sendto(daemon_notifier_fd, buf, len, 0,
1289 (const struct sockaddr *)&sa_un, msg.msg_namelen) < 0)
1290 log_write(0, LOG_MAIN|LOG_PANIC,
1291 "%s: sendto: %s\n", __FUNCTION__, strerror(errno));
1299 /*************************************************
1300 * Exim Daemon Mainline *
1301 *************************************************/
1303 /* The daemon can do two jobs, either of which is optional:
1305 (1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1306 each one. This is requested by the -bd option, with -oX specifying the SMTP
1307 port on which to listen (for testing).
1309 (2) Spawns a queue-running process every so often. This is controlled by the
1310 -q option with a an interval time. (If no time is given, a single queue run
1311 is done from the main function, and control doesn't get here.)
1313 Root privilege is required in order to attach to port 25. Some systems require
1314 it when calling socket() rather than bind(). To cope with all cases, we run as
1315 root for both socket() and bind(). Some systems also require root in order to
1316 write to the pid file directory. This function must therefore be called as root
1317 if it is to work properly in all circumstances. Once the socket is bound and
1318 the pid file written, root privilege is given up if there is an exim uid.
1320 There are no arguments to this function, and it never returns. */
1326 int *listen_sockets = NULL;
1327 int listen_socket_count = 0;
1328 ip_address_item *addresses = NULL;
1329 time_t last_connection_time = (time_t)0;
1330 int local_queue_run_max = atoi(CS expand_string(queue_run_max));
1332 process_purpose = US"daemon";
1334 /* If any debugging options are set, turn on the D_pid bit so that all
1335 debugging lines get the pid added. */
1337 DEBUG(D_any|D_v) debug_selector |= D_pid;
1339 if (f.inetd_wait_mode)
1341 listen_socket_count = 1;
1342 listen_sockets = store_get(sizeof(int), FALSE);
1344 if (dup2(0, 3) == -1)
1345 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1346 "failed to dup inetd socket safely away: %s", strerror(errno));
1348 listen_sockets[0] = 3;
1354 if (debug_file == stderr)
1356 /* need a call to log_write before call to open debug_file, so that
1357 log.c:file_path has been initialised. This is unfortunate. */
1358 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1362 exim_nullstd(); /* re-open fd2 after we just closed it again */
1363 debug_logging_activate(US"-wait", NULL);
1366 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1368 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1369 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1372 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1373 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1378 if (f.inetd_wait_mode || f.daemon_listen)
1380 /* If any option requiring a load average to be available during the
1381 reception of a message is set, call os_getloadavg() while we are root
1382 for those OS for which this is necessary the first time it is called (in
1383 order to perform an "open" on the kernel memory file). */
1385 #ifdef LOAD_AVG_NEEDS_ROOT
1386 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1387 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1388 (void)os_getloadavg();
1393 /* Do the preparation for setting up a listener on one or more interfaces, and
1394 possible on various ports. This is controlled by the combination of
1395 local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1396 (which is a list of default ports to use for those items in local_interfaces
1397 that do not specify a port). The -oX command line option can be used to
1398 override one or both of these options.
1400 If local_interfaces is not set, the default is to listen on all interfaces.
1401 When it is set, it can include "all IPvx interfaces" as an item. This is useful
1402 when different ports are in use.
1404 It turns out that listening on all interfaces is messy in an IPv6 world,
1405 because several different implementation approaches have been taken. This code
1406 is now supposed to work with all of them. The point of difference is whether an
1407 IPv6 socket that is listening on all interfaces will receive incoming IPv4
1408 calls or not. We also have to cope with the case when IPv6 libraries exist, but
1409 there is no IPv6 support in the kernel.
1411 . On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1412 addresses. However, if an IPv4 socket is also listening on all interfaces,
1413 calls are directed to the appropriate socket.
1415 . On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1416 give them as mapped addresses, but an attempt also to listen on an IPv4
1417 socket on all interfaces causes an error.
1419 . On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1420 two sockets if you want to accept both kinds of call.
1422 . FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1423 can be turned off, to make it behave like the versions of Linux described
1426 . I heard a report that the USAGI IPv6 stack for Linux has implemented
1429 So, what we do when IPv6 is supported is as follows:
1431 (1) After it is set up, the list of interfaces is scanned for wildcard
1432 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1433 port, the list is re-arranged so that they are together, with the IPv6
1436 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1437 carry on if an IPv4 wildcard socket for the same port follows later in the
1438 list. This allows Exim to carry on in the case when the kernel has no IPv6
1441 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1442 option is defined. However, if setting fails, carry on regardless (but log
1445 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1448 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1449 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1450 port (which must have succeeded or we wouldn't have got this far), we
1451 assume we are in the situation where just a single socket is permitted,
1452 and ignore the error.
1456 The preparation code decodes options and sets up the relevant data. We do this
1457 first, so that we can return non-zero if there are any syntax errors, and also
1460 if (f.daemon_listen && !f.inetd_wait_mode)
1462 int *default_smtp_port;
1466 const uschar * list;
1467 uschar *local_iface_source = US"local_interfaces";
1468 ip_address_item *ipa;
1469 ip_address_item **pipa;
1471 /* If -oX was used, disable the writing of a pid file unless -oP was
1472 explicitly used to force it. Then scan the string given to -oX. Any items
1473 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1474 Any other items are used to override local_interfaces. */
1476 if (override_local_interfaces)
1478 gstring * new_smtp_port = NULL;
1479 gstring * new_local_interfaces = NULL;
1481 if (!override_pid_file_path) write_pid = FALSE;
1483 list = override_local_interfaces;
1485 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
1488 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
1494 *gp = string_catn(*gp, US"<", 1);
1497 *gp = string_catn(*gp, joinstr, 2);
1498 *gp = string_cat (*gp, s);
1503 daemon_smtp_port = string_from_gstring(new_smtp_port);
1504 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1508 if (new_local_interfaces)
1510 local_interfaces = string_from_gstring(new_local_interfaces);
1511 local_iface_source = US"-oX data";
1512 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1517 /* Create a list of default SMTP ports, to be used if local_interfaces
1518 contains entries without explicit ports. First count the number of ports, then
1519 build a translated list in a vector. */
1521 list = daemon_smtp_port;
1523 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
1525 default_smtp_port = store_get((pct+1) * sizeof(int), FALSE);
1526 list = daemon_smtp_port;
1529 (s = string_nextinlist(&list, &sep, NULL, 0));
1535 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1536 if (end != s + Ustrlen(s))
1537 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1541 struct servent *smtp_service = getservbyname(CS s, "tcp");
1543 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1544 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1547 default_smtp_port[pct] = 0;
1549 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1551 list = tls_in.on_connect_ports;
1553 /* the list isn't expanded so cannot be tainted. If it ever is we will trap here */
1554 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1559 list = tls_in.on_connect_ports;
1560 tls_in.on_connect_ports = NULL;
1562 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1566 struct servent * smtp_service = getservbyname(CS s, "tcp");
1568 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1569 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
1571 g = string_append_listele(g, ':', s);
1574 tls_in.on_connect_ports = g->s;
1578 /* Create the list of local interfaces, possibly with ports included. This
1579 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1580 values are converted below. */
1582 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1584 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1585 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1586 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1587 anyway, but we need to know which are the wildcard addresses, and the shorter
1590 In the same scan, fill in missing port numbers from the default list. When
1591 there is more than one item in the list, extra items are created. */
1593 for (ipa = addresses; ipa; ipa = ipa->next)
1595 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1596 ipa->address[0] = 0;
1597 else if (Ustrcmp(ipa->address, "::0") == 0)
1599 ipa->address[0] = ':';
1600 ipa->address[1] = 0;
1603 if (ipa->port > 0) continue;
1605 if (daemon_smtp_port[0] <= 0)
1606 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1607 "%s and daemon_smtp_port is unset; cannot start daemon",
1608 ipa->address[0] == 0 ? US"\"all IPv4\"" :
1609 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
1611 ipa->port = default_smtp_port[0];
1612 for (int i = 1; default_smtp_port[i] > 0; i++)
1614 ip_address_item *new = store_get(sizeof(ip_address_item), FALSE);
1616 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1617 new->port = default_smtp_port[i];
1618 new->next = ipa->next;
1624 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1625 wildcard for the same port, ensure that (a) they are together and (b) the
1626 IPv6 address comes first. This makes handling the messy features easier, and
1627 also simplifies the construction of the "daemon started" log line. */
1630 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
1632 ip_address_item *ipa2;
1634 /* Handle an IPv4 wildcard */
1636 if (ipa->address[0] == 0)
1637 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1639 ip_address_item *ipa3 = ipa2->next;
1640 if (ipa3->address[0] == ':' &&
1641 ipa3->address[1] == 0 &&
1642 ipa3->port == ipa->port)
1644 ipa2->next = ipa3->next;
1651 /* Handle an IPv6 wildcard. */
1653 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
1654 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1656 ip_address_item *ipa3 = ipa2->next;
1657 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1659 ipa2->next = ipa3->next;
1660 ipa3->next = ipa->next;
1668 /* Get a vector to remember all the sockets in */
1670 for (ipa = addresses; ipa; ipa = ipa->next)
1671 listen_socket_count++;
1672 listen_sockets = store_get(sizeof(int) * listen_socket_count, FALSE);
1674 } /* daemon_listen but not inetd_wait_mode */
1676 if (f.daemon_listen)
1679 /* Do a sanity check on the max connects value just to save us from getting
1680 a huge amount of store. */
1682 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1684 /* There's no point setting smtp_accept_queue unless it is less than the max
1685 connects limit. The configuration reader ensures that the max is set if the
1686 queue-only option is set. */
1688 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1690 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1691 track of them for total number and queue/host limits. */
1693 if (smtp_accept_max > 0)
1695 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), FALSE);
1696 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
1700 /* The variable background_daemon is always false when debugging, but
1701 can also be forced false in order to keep a non-debugging daemon in the
1702 foreground. If background_daemon is true, close all open file descriptors that
1703 we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1704 do this for inetd_wait mode.
1706 This is protection against any called functions (in libraries, or in
1707 Perl, or whatever) that think they can write to stderr (or stdout). Before this
1708 was added, it was quite likely that an SMTP connection would use one of these
1709 file descriptors, in which case writing random stuff to it caused chaos.
1711 Then disconnect from the controlling terminal, Most modern Unixes seem to have
1712 setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1713 setsid() can be #defined as a no-op, or as something else. */
1715 if (f.background_daemon || f.inetd_wait_mode)
1717 log_close_all(); /* Just in case anything was logged earlier */
1718 search_tidyup(); /* Just in case any were used in reading the config. */
1719 (void)close(0); /* Get rid of stdin/stdout/stderr */
1722 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
1723 log_stderr = NULL; /* So no attempt to copy paniclog output */
1726 if (f.background_daemon)
1728 /* If the parent process of this one has pid == 1, we are re-initializing the
1729 daemon as the result of a SIGHUP. In this case, there is no need to do
1730 anything, because the controlling terminal has long gone. Otherwise, fork, in
1731 case current process is a process group leader (see 'man setsid' for an
1732 explanation) before calling setsid(). */
1736 pid_t pid = exim_fork(US"daemon");
1737 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1738 "fork() failed when starting daemon: %s", strerror(errno));
1739 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1740 (void)setsid(); /* release controlling terminal */
1744 /* We are now in the disconnected, daemon process (unless debugging). Set up
1745 the listening sockets if required. */
1747 daemon_notifier_socket();
1749 if (f.daemon_listen && !f.inetd_wait_mode)
1752 ip_address_item *ipa;
1754 /* For each IP address, create a socket, bind it to the appropriate port, and
1755 start listening. See comments above about IPv6 sockets that may or may not
1756 accept IPv4 calls when listening on all interfaces. We also have to cope with
1757 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1758 listening, provided a wildcard IPv4 socket for the same port follows. */
1760 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1763 ip_address_item *ipa2;
1766 if (Ustrchr(ipa->address, ':') != NULL)
1769 wildcard = ipa->address[1] == 0;
1774 wildcard = ipa->address[0] == 0;
1777 if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0)
1779 if (check_special_case(0, addresses, ipa, FALSE))
1781 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1782 "listening (%s): will use IPv4", strerror(errno));
1785 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1786 (af == AF_INET6)? '6' : '4', strerror(errno));
1789 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1790 available. Just log failure (can get protocol not available, just like
1791 socket creation can). */
1794 if (af == AF_INET6 && wildcard &&
1795 setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, CS (&on),
1797 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1798 "socket failed (%s): carrying on without it", strerror(errno));
1799 #endif /* IPV6_V6ONLY */
1801 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1802 is being handled. Without this, a connection will prevent reuse of the
1803 smtp port for listening. */
1805 if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR,
1806 US (&on), sizeof(on)) < 0)
1807 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1808 "failed when starting daemon: %s", strerror(errno));
1810 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1811 disable this because it breaks some broken clients. */
1813 if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY,
1814 US (&on), sizeof(on));
1816 /* Now bind the socket to the required port; if Exim is being restarted
1817 it may not always be possible to bind immediately, even with SO_REUSEADDR
1818 set, so try 10 times, waiting between each try. After 10 failures, we give
1819 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1820 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1821 address for the same port, ignore the error on the grounds that we must be
1822 in a system where the IPv6 socket accepts both kinds of call. This is
1823 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1824 listen() stage instead. */
1827 f.tcp_fastopen_ok = TRUE;
1832 if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break;
1833 if (check_special_case(errno, addresses, ipa, TRUE))
1835 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1836 "listen() success; EADDRINUSE ignored\n");
1837 (void)close(listen_sockets[sk]);
1840 msg = US strerror(errno);
1846 if (daemon_startup_retries <= 0)
1847 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1848 "socket bind() to port %d for address %s failed: %s: "
1849 "daemon abandoned", ipa->port, addr, msg);
1850 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
1851 "failed: %s: waiting %s before trying again (%d more %s)",
1852 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1853 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1854 daemon_startup_retries--;
1855 sleep(daemon_startup_sleep);
1860 debug_printf("listening on all interfaces (IPv%c) port %d\n",
1861 af == AF_INET6 ? '6' : '4', ipa->port);
1863 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
1865 #if defined(TCP_FASTOPEN) && !defined(__APPLE__)
1866 if ( f.tcp_fastopen_ok
1867 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1868 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
1870 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1871 f.tcp_fastopen_ok = FALSE;
1875 /* Start listening on the bound socket, establishing the maximum backlog of
1876 connections that is allowed. On success, continue to the next address. */
1878 if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0)
1880 #if defined(TCP_FASTOPEN) && defined(__APPLE__)
1881 if ( f.tcp_fastopen_ok
1882 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1885 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1886 f.tcp_fastopen_ok = FALSE;
1892 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1893 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1894 and there was a previous successful IPv6 wildcard listen on the same port,
1895 we want to ignore the error on the grounds that we must be in a system
1896 where the IPv6 socket accepts both kinds of call. */
1898 if (!check_special_case(errno, addresses, ipa, TRUE))
1899 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
1901 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
1904 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1905 "listen() success; EADDRINUSE ignored\n");
1906 (void)close(listen_sockets[sk]);
1908 /* Come here if there has been a problem with the socket which we
1909 are going to ignore. We remove the address from the chain, and back up the
1913 sk--; /* Back up the count */
1914 listen_socket_count--; /* Reduce the total */
1915 if (ipa == addresses) addresses = ipa->next; else
1917 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1918 ipa2->next = ipa->next;
1921 } /* End of bind/listen loop for each address */
1922 } /* End of setup for listening */
1925 /* If we are not listening, we want to write a pid file only if -oP was
1926 explicitly given. */
1928 else if (!override_pid_file_path)
1931 /* Write the pid to a known file for assistance in identification, if required.
1932 We do this before giving up root privilege, because on some systems it is
1933 necessary to be root in order to write into the pid file directory. There's
1934 nothing to stop multiple daemons running, as long as no more than one listens
1935 on a given TCP/IP port on the same interface(s). However, in these
1936 circumstances it gets far too complicated to mess with pid file names
1937 automatically. Consequently, Exim 4 writes a pid file only
1939 (a) When running in the test harness, or
1940 (b) When -bd is used and -oX is not used, or
1941 (c) When -oP is used to supply a path.
1943 The variable daemon_write_pid is used to control this. */
1945 if (f.running_in_test_harness || write_pid)
1947 const enum pid_op operation = (f.running_in_test_harness
1948 || real_uid == root_uid
1949 || (real_uid == exim_uid && !override_pid_file_path)) ? PID_WRITE : PID_CHECK;
1950 if (!operate_on_pid_file(operation, getpid()))
1951 DEBUG(D_any) debug_printf("%s pid file %s: %s\n", (operation == PID_WRITE) ? "write" : "check", pid_file_path, strerror(errno));
1954 /* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1955 sighup_seen = FALSE;
1956 signal(SIGHUP, sighup_handler);
1958 /* Give up root privilege at this point (assuming that exim_uid and exim_gid
1959 are not root). The third argument controls the running of initgroups().
1960 Normally we do this, in order to set up the groups for the Exim user. However,
1961 if we are not root at this time - some odd installations run that way - we
1964 exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1966 /* Update the originator_xxx fields so that received messages as listed as
1967 coming from Exim, not whoever started the daemon. */
1969 originator_uid = exim_uid;
1970 originator_gid = exim_gid;
1971 originator_login = (pw = getpwuid(exim_uid))
1972 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
1974 /* Get somewhere to keep the list of queue-runner pids if we are keeping track
1975 of them (and also if we are doing queue runs). */
1977 if (queue_interval > 0 && local_queue_run_max > 0)
1979 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t), FALSE);
1980 for (int i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
1983 /* Set up the handler for termination of child processes, and the one
1984 telling us to die. */
1986 sigchld_seen = FALSE;
1987 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
1989 sigterm_seen = FALSE;
1990 os_non_restarting_signal(SIGTERM, main_sigterm_handler);
1991 os_non_restarting_signal(SIGINT, main_sigterm_handler);
1993 /* If we are to run the queue periodically, pretend the alarm has just gone
1994 off. This will cause the first queue-runner to get kicked off straight away. */
1996 sigalrm_seen = (queue_interval > 0);
1998 /* Log the start up of a daemon - at least one of listening or queue running
2001 if (f.inetd_wait_mode)
2003 uschar *p = big_buffer;
2005 if (inetd_wait_timeout >= 0)
2006 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
2008 sprintf(CS p, "with no wait timeout");
2010 log_write(0, LOG_MAIN,
2011 "exim %s daemon started: pid=%d, launched with listening socket, %s",
2012 version_string, getpid(), big_buffer);
2013 set_process_info("daemon(%s): pre-listening socket", version_string);
2015 /* set up the timeout logic */
2016 sigalrm_seen = TRUE;
2019 else if (f.daemon_listen)
2022 int smtps_ports = 0;
2023 ip_address_item * ipa;
2025 uschar * qinfo = queue_interval > 0
2026 ? string_sprintf("-q%s%s",
2027 f.queue_2stage ? "q" : "", readconf_printtime(queue_interval))
2028 : US"no queue runs";
2030 /* Build a list of listening addresses in big_buffer, but limit it to 10
2031 items. The style is for backwards compatibility.
2033 It is now possible to have some ports listening for SMTPS (the old,
2034 deprecated protocol that starts TLS without using STARTTLS), and others
2035 listening for standard SMTP. Keep their listings separate. */
2037 for (int j = 0, i; j < 2; j++)
2039 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
2041 /* First time round, look for SMTP ports; second time round, look for
2042 SMTPS ports. Build IP+port strings. */
2044 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
2051 /* Now the information about the port (and sometimes interface) */
2053 if (ipa->address[0] == ':' && ipa->address[1] == 0)
2055 if (ipa->next && ipa->next->address[0] == 0 &&
2056 ipa->next->port == ipa->port)
2058 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
2059 (ipa = ipa->next)->log = NULL;
2061 else if (ipa->v6_include_v4)
2062 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
2064 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
2066 else if (ipa->address[0] == 0) /* v4 wildcard */
2067 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
2068 else /* check for previously-seen IP */
2070 ip_address_item * i2;
2071 for (i2 = addresses; i2 != ipa; i2 = i2->next)
2072 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
2073 && Ustrcmp(ipa->address, i2->address) == 0
2075 { /* found; append port to list */
2076 for (p = i2->log; *p; ) p++; /* end of existing string */
2077 if (*--p == '}') *p = '\0'; /* drop EOL */
2078 while (isdigit(*--p)) ; /* char before port */
2080 i2->log = *p == ':' /* no list yet? */
2081 ? string_sprintf("%.*s{%s,%d}",
2082 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
2083 : string_sprintf("%s,%d}", i2->log, ipa->port);
2087 if (i2 == ipa) /* first-time IP */
2088 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
2095 for (int j = 0, i; j < 2; j++)
2097 /* First time round, look for SMTP ports; second time round, look for
2098 SMTPS ports. For the first one of each, insert leading text. */
2103 p += sprintf(CS p, "SMTP on");
2106 if (smtps_ports > 0)
2107 p += sprintf(CS p, "%sSMTPS on",
2108 smtp_ports == 0 ? "" : " and for ");
2110 /* Now the information about the port (and sometimes interface) */
2112 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
2113 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
2115 p += sprintf(CS p, "%s", ipa->log);
2118 p += sprintf(CS p, " ...");
2121 log_write(0, LOG_MAIN,
2122 "exim %s daemon started: pid=%d, %s, listening for %s",
2123 version_string, getpid(), qinfo, big_buffer);
2124 set_process_info("daemon(%s): %s, listening for %s",
2125 version_string, qinfo, big_buffer);
2130 uschar * s = *queue_name
2131 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
2132 : string_sprintf("-q%s", readconf_printtime(queue_interval));
2133 log_write(0, LOG_MAIN,
2134 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
2135 version_string, getpid(), s);
2136 set_process_info("daemon(%s): %s, not listening", version_string, s);
2139 /* Do any work it might be useful to amortize over our children
2140 (eg: compile regex) */
2143 smtp_deliver_init(); /* Used for callouts */
2145 #ifndef DISABLE_DKIM
2147 # ifdef MEASURE_TIMING
2149 gettimeofday(&t0, NULL);
2152 # ifdef MEASURE_TIMING
2153 report_time_since(&t0, US"dkim_exim_init (delta)");
2158 #ifdef WITH_CONTENT_SCAN
2168 /* Close the log so it can be renamed and moved. In the few cases below where
2169 this long-running process writes to the log (always exceptional conditions), it
2170 closes the log afterwards, for the same reason. */
2174 DEBUG(D_any) debug_print_ids(US"daemon running with");
2176 /* Any messages accepted via this route are going to be SMTP. */
2180 #ifdef MEASURE_TIMING
2181 report_time_since(×tamp_startup, US"daemon loop start"); /* testcase 0022 */
2184 /* Enter the never-ending loop... */
2189 struct sockaddr_in6 accepted;
2191 struct sockaddr_in accepted;
2198 daemon_die(); /* Does not return */
2200 /* This code is placed first in the loop, so that it gets obeyed at the
2201 start, before the first wait, for the queue-runner case, so that the first
2202 one can be started immediately.
2204 The other option is that we have an inetd wait timeout specified to -bw. */
2208 if (inetd_wait_timeout > 0)
2210 time_t resignal_interval = inetd_wait_timeout;
2212 if (last_connection_time == (time_t)0)
2215 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
2219 time_t now = time(NULL);
2220 if (now == (time_t)-1)
2222 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
2226 if ((now - last_connection_time) >= inetd_wait_timeout)
2229 debug_printf("inetd wait timeout %d expired, ending daemon\n",
2230 inetd_wait_timeout);
2231 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
2237 resignal_interval -= (now - last_connection_time);
2242 sigalrm_seen = FALSE;
2243 ALARM(resignal_interval);
2248 DEBUG(D_any) debug_printf("%s received\n",
2249 #ifndef DISABLE_QUEUE_RAMP
2250 *queuerun_msgid ? "qrun notification" :
2254 /* Do a full queue run in a child process, if required, unless we already
2255 have enough queue runners on the go. If we are not running as root, a
2256 re-exec is required. */
2258 if ( queue_interval > 0
2259 && (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
2261 if ((pid = exim_fork(US"queue-runner")) == 0)
2263 /* Disable debugging if it's required only for the daemon process. We
2264 leave the above message, because it ties up with the "child ended"
2265 debugging messages. */
2267 if (f.debug_daemon) debug_selector = 0;
2269 /* Close any open listening sockets in the child */
2271 close_daemon_sockets(daemon_notifier_fd,
2272 listen_sockets, listen_socket_count);
2274 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
2276 signal(SIGHUP, SIG_DFL);
2277 signal(SIGCHLD, SIG_DFL);
2278 signal(SIGTERM, SIG_DFL);
2279 signal(SIGINT, SIG_DFL);
2281 /* Re-exec if privilege has been given up, unless deliver_drop_
2282 privilege is set. Reset SIGALRM before exec(). */
2284 if (geteuid() != root_uid && !deliver_drop_privilege)
2291 signal(SIGALRM, SIG_DFL);
2295 #ifndef DISABLE_QUEUE_RAMP
2299 if (f.queue_run_first_delivery) *p++ = 'i';
2300 if (f.queue_run_force) *p++ = 'f';
2301 if (f.deliver_force_thaw) *p++ = 'f';
2302 if (f.queue_run_local) *p++ = 'l';
2304 extra[0] = *queue_name
2305 ? string_sprintf("%sG%s", opt, queue_name) : opt;
2307 #ifndef DISABLE_QUEUE_RAMP
2308 if (*queuerun_msgid)
2310 log_write(0, LOG_MAIN, "notify triggered queue run");
2311 extra[extracount++] = queuerun_msgid; /* Trigger only the */
2312 extra[extracount++] = queuerun_msgid; /* one message */
2316 /* If -R or -S were on the original command line, ensure they get
2319 if (deliver_selectstring)
2321 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
2322 extra[extracount++] = deliver_selectstring;
2325 if (deliver_selectstring_sender)
2327 extra[extracount++] = f.deliver_selectstring_sender_regex
2329 extra[extracount++] = deliver_selectstring_sender;
2332 /* Overlay this process with a new execution. */
2334 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
2335 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
2337 /* Control never returns here. */
2340 /* No need to re-exec; SIGALRM remains set to the default handler */
2342 #ifndef DISABLE_QUEUE_RAMP
2343 if (*queuerun_msgid)
2345 log_write(0, LOG_MAIN, "notify triggered queue run");
2346 f.queue_2stage = FALSE;
2347 queue_run(queuerun_msgid, queuerun_msgid, FALSE);
2351 queue_run(NULL, NULL, FALSE);
2352 exim_underbar_exit(EXIT_SUCCESS);
2357 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
2358 "process failed: %s", strerror(errno));
2363 for (int i = 0; i < local_queue_run_max; ++i)
2364 if (queue_pid_slots[i] <= 0)
2366 queue_pid_slots[i] = pid;
2370 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
2371 queue_run_count, queue_run_count == 1 ? "" : "es");
2375 /* Reset the alarm clock */
2377 sigalrm_seen = FALSE;
2378 #ifndef DISABLE_QUEUE_RAMP
2379 if (*queuerun_msgid)
2380 *queuerun_msgid = 0;
2383 ALARM(queue_interval);
2386 } /* sigalrm_seen */
2389 /* Sleep till a connection happens if listening, and handle the connection if
2390 that is why we woke up. The FreeBSD operating system requires the use of
2391 select() before accept() because the latter function is not interrupted by
2392 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2393 OS do notice signals in accept() but it does no harm to have the select()
2394 in for all of them - and it won't then be a lurking problem for ports to
2395 new OS. In fact, the later addition of listening on specific interfaces only
2396 requires this way of working anyway. */
2398 if (f.daemon_listen)
2402 BOOL select_failed = FALSE;
2403 fd_set select_listen;
2405 FD_ZERO(&select_listen);
2407 if (tls_watch_fd >= 0)
2409 FD_SET(tls_watch_fd, &select_listen);
2410 if (tls_watch_fd > max_socket) max_socket = tls_watch_fd;
2413 if (daemon_notifier_fd >= 0)
2415 FD_SET(daemon_notifier_fd, &select_listen);
2416 if (daemon_notifier_fd > max_socket) max_socket = daemon_notifier_fd;
2418 for (int sk = 0; sk < listen_socket_count; sk++)
2420 FD_SET(listen_sockets[sk], &select_listen);
2421 if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk];
2424 DEBUG(D_any) debug_printf("Listening...\n");
2426 /* In rare cases we may have had a SIGCHLD signal in the time between
2427 setting the handler (below) and getting back here. If so, pretend that the
2428 select() was interrupted so that we reap the child. This might still leave
2429 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
2430 only to do the reaping more quickly, it shouldn't result in anything other
2431 than a delay until something else causes a wake-up. */
2439 lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen,
2444 select_failed = TRUE;
2448 /* Clean up any subprocesses that may have terminated. We need to do this
2449 here so that smtp_accept_max_per_host works when a connection to that host
2450 has completed, and we are about to accept a new one. When this code was
2451 later in the sequence, a new connection could be rejected, even though an
2452 old one had just finished. Preserve the errno from any select() failure for
2453 the use of the common select/accept error processing below. */
2456 int select_errno = errno;
2457 handle_ending_processes();
2460 /* Create or rotate any required keys; handle (delayed) filewatch event */
2463 errno = select_errno;
2466 /* Loop for all the sockets that are currently ready to go. If select
2467 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2468 to use the common error code for select/accept below. */
2470 while (lcount-- > 0)
2472 int accept_socket = -1;
2476 #if !defined(DISABLE_TLS) && (defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT))
2477 if (tls_watch_fd >= 0 && FD_ISSET(tls_watch_fd, &select_listen))
2479 FD_CLR(tls_watch_fd, &select_listen);
2480 tls_watch_trigger_time = time(NULL); /* Set up delayed event */
2481 tls_watch_discard_event(tls_watch_fd);
2482 break; /* to top of daemon loop */
2485 if ( daemon_notifier_fd >= 0
2486 && FD_ISSET(daemon_notifier_fd, &select_listen))
2488 FD_CLR(daemon_notifier_fd, &select_listen);
2489 sigalrm_seen = daemon_notification();
2490 break; /* to top of daemon loop */
2492 for (int sk = 0; sk < listen_socket_count; sk++)
2493 if (FD_ISSET(listen_sockets[sk], &select_listen))
2495 len = sizeof(accepted);
2496 accept_socket = accept(listen_sockets[sk],
2497 (struct sockaddr *)&accepted, &len);
2498 FD_CLR(listen_sockets[sk], &select_listen);
2503 /* If select or accept has failed and this was not caused by an
2504 interruption, log the incident and try again. With asymmetric TCP/IP
2505 routing errors such as "No route to network" have been seen here. Also
2506 "connection reset by peer" has been seen. These cannot be classed as
2507 disastrous errors, but they could fill up a lot of log. The code in smail
2508 crashes the daemon after 10 successive failures of accept, on the grounds
2509 that some OS fail continuously. Exim originally followed suit, but this
2510 appears to have caused problems. Now it just keeps going, but instead of
2511 logging each error, it batches them up when they are continuous. */
2513 if (accept_socket < 0 && errno != EINTR)
2515 if (accept_retry_count == 0)
2517 accept_retry_errno = errno;
2518 accept_retry_select_failed = select_failed;
2520 else if ( errno != accept_retry_errno
2521 || select_failed != accept_retry_select_failed
2522 || accept_retry_count >= 50)
2524 log_write(0, LOG_MAIN | (accept_retry_count >= 50 ? LOG_PANIC : 0),
2525 "%d %s() failure%s: %s",
2527 accept_retry_select_failed ? "select" : "accept",
2528 accept_retry_count == 1 ? "" : "s",
2529 strerror(accept_retry_errno));
2531 accept_retry_count = 0;
2532 accept_retry_errno = errno;
2533 accept_retry_select_failed = select_failed;
2535 accept_retry_count++;
2537 else if (accept_retry_count > 0)
2539 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2541 accept_retry_select_failed ? "select" : "accept",
2542 accept_retry_count == 1 ? "" : "s",
2543 strerror(accept_retry_errno));
2545 accept_retry_count = 0;
2548 /* If select/accept succeeded, deal with the connection. */
2550 if (accept_socket >= 0)
2552 #ifdef TCP_QUICKACK /* Avoid pure-ACKs while in tls protocol pingpong phase */
2553 /* Unfortunately we cannot be certain to do this before a TLS-on-connect
2554 Client Hello arrives and is acked. We do it as early as possible. */
2555 (void) setsockopt(accept_socket, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
2557 if (inetd_wait_timeout)
2558 last_connection_time = time(NULL);
2559 handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,
2560 (struct sockaddr *)&accepted);
2565 /* If not listening, then just sleep for the queue interval. If we woke
2566 up early the last time for some other signal, it won't matter because
2567 the alarm signal will wake at the right time. This code originally used
2568 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2569 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2570 select() can be used as an interruptible sleep() on all versions of Unix. */
2575 tv.tv_sec = queue_interval;
2577 select(0, NULL, NULL, NULL, &tv);
2578 handle_ending_processes();
2581 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2582 for itself, because it isn't doing the waiting itself. */
2586 sigchld_seen = FALSE;
2587 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
2590 /* Handle being woken by SIGHUP. We know at this point that the result
2591 of accept() has been dealt with, so we can re-exec exim safely, first
2592 closing the listening sockets so that they can be reused. Cancel any pending
2593 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2594 that another HUP in quick succession doesn't clobber the new daemon before it
2595 gets going. All log files get closed by the close-on-exec flag; however, if
2596 the exec fails, we need to close the logs. */
2600 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2602 close_daemon_sockets(daemon_notifier_fd,
2603 listen_sockets, listen_socket_count);
2605 signal(SIGHUP, SIG_IGN);
2606 sighup_argv[0] = exim_path;
2608 execv(CS exim_path, (char *const *)sighup_argv);
2609 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2610 getpid(), exim_path, strerror(errno));
2614 } /* End of main loop */
2616 /* Control never reaches here */
2621 /* End of exim_daemon.c */