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
957 operate_on_pid_file(const enum pid_op operation, const pid_t pid)
959 char pid_line[sizeof(int) * 3 + 2];
960 const int pid_len = snprintf(pid_line, sizeof(pid_line), "%d\n", (int)pid);
961 BOOL lines_match = FALSE;
967 const int dir_flags = O_RDONLY | O_NONBLOCK;
968 const int base_flags = O_NOFOLLOW | O_NONBLOCK;
969 const mode_t base_mode = 0644;
976 BOOL success = FALSE;
980 if (!f.running_in_test_harness && real_uid != root_uid && real_uid != exim_uid) goto cleanup;
981 if (pid_len < 2 || pid_len >= (int)sizeof(pid_line)) goto cleanup;
983 path = CS string_copy(pid_file_path);
984 if ((base = Ustrrchr(path, '/')) == NULL) /* should not happen, but who knows */
985 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid file path \"%s\" does not contain a '/'", pid_file_path);
987 dir = (base != path) ? path : "/";
990 if (!dir || !*dir || *dir != '/') goto cleanup;
991 if (!base || !*base || strchr(base, '/') != NULL) goto cleanup;
993 cwd_fd = open(".", dir_flags);
994 if (cwd_fd < 0 || fstat(cwd_fd, &sb) != 0 || !S_ISDIR(sb.st_mode)) goto cleanup;
995 dir_fd = open(dir, dir_flags);
996 if (dir_fd < 0 || fstat(dir_fd, &sb) != 0 || !S_ISDIR(sb.st_mode)) goto cleanup;
999 if (fchdir(dir_fd) != 0) goto cleanup;
1000 base_fd = open(base, O_RDONLY | base_flags);
1001 if (fchdir(cwd_fd) != 0)
1002 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1006 char line[sizeof(pid_line)];
1009 if (fstat(base_fd, &sb) != 0 || !S_ISREG(sb.st_mode)) goto cleanup;
1010 if ((sb.st_mode & 07777) != base_mode || sb.st_nlink != 1) goto cleanup;
1011 if (sb.st_size < 2 || sb.st_size >= (off_t)sizeof(line)) goto cleanup;
1013 len = read(base_fd, line, sizeof(line));
1014 if (len != (ssize_t)sb.st_size) goto cleanup;
1017 if (strspn(line, "0123456789") != (size_t)len-1) goto cleanup;
1018 if (line[len-1] != '\n') goto cleanup;
1019 lines_match = (len == pid_len && strcmp(line, pid_line) == 0);
1022 if (operation == PID_WRITE)
1029 /* emulate unlinkat */
1030 if (fchdir(dir_fd) != 0) goto cleanup;
1031 error = unlink(base);
1032 if (fchdir(cwd_fd) != 0)
1033 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1034 if (error) goto cleanup;
1035 (void)close(base_fd);
1038 /* emulate openat */
1039 if (fchdir(dir_fd) != 0) goto cleanup;
1040 base_fd = open(base, O_WRONLY | O_CREAT | O_EXCL | base_flags, base_mode);
1041 if (fchdir(cwd_fd) != 0)
1042 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1043 if (base_fd < 0) goto cleanup;
1044 if (fchmod(base_fd, base_mode) != 0) goto cleanup;
1045 if (write(base_fd, pid_line, pid_len) != pid_len) goto cleanup;
1046 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1051 if (!lines_match) goto cleanup;
1052 if (operation == PID_DELETE)
1055 /* emulate unlinkat */
1056 if (fchdir(dir_fd) != 0) goto cleanup;
1057 error = unlink(base);
1058 if (fchdir(cwd_fd) != 0)
1059 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno));
1060 if (error) goto cleanup;
1068 if (cwd_fd >= 0) (void)close(cwd_fd);
1069 if (dir_fd >= 0) (void)close(dir_fd);
1070 if (base_fd >= 0) (void)close(base_fd);
1075 /* Remove the daemon's pidfile. Note: runs with root privilege,
1076 as a direct child of the daemon. Does not return. */
1079 delete_pid_file(void)
1081 const BOOL success = operate_on_pid_file(PID_DELETE, getppid());
1084 debug_printf("delete pid file %s %s: %s\n", pid_file_path,
1085 success ? "success" : "failure", strerror(errno));
1087 exim_exit(EXIT_SUCCESS);
1091 /* Called by the daemon; exec a child to get the pid file deleted
1092 since we may require privs for the containing directory */
1099 DEBUG(D_any) debug_printf("SIGTERM/SIGINT seen\n");
1100 #if !defined(DISABLE_TLS) && (defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT))
1101 tls_watch_invalidate();
1104 if (daemon_notifier_fd >= 0)
1106 close(daemon_notifier_fd);
1107 daemon_notifier_fd = -1;
1108 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1109 unlink_notifier_socket();
1113 if (f.running_in_test_harness || write_pid)
1115 if ((pid = exim_fork(US"daemon-del-pidfile")) == 0)
1117 if (override_pid_file_path)
1118 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 3,
1119 "-oP", override_pid_file_path, "-oPX");
1121 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, 1, "-oPX");
1123 /* Control never returns here. */
1126 child_close(pid, 1);
1128 exim_exit(EXIT_SUCCESS);
1132 /*************************************************
1133 * Listener socket for local work prompts *
1134 *************************************************/
1137 daemon_notifier_socket(void)
1140 const uschar * where;
1141 struct sockaddr_un sa_un = {.sun_family = AF_UNIX};
1144 if (!notifier_socket || !*notifier_socket)
1146 DEBUG(D_any) debug_printf("-oY used so not creating notifier socket\n");
1149 if (override_local_interfaces && !override_pid_file_path)
1152 debug_printf("-oX used without -oP so not creating notifier socket\n");
1156 DEBUG(D_any) debug_printf("creating notifier socket\n");
1159 if ((fd = socket(PF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0)
1160 { where = US"socket"; goto bad; }
1162 if ((fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0)
1163 { where = US"socket"; goto bad; }
1164 (void)fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
1167 #ifdef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1168 sa_un.sun_path[0] = 0; /* Abstract local socket addr - Linux-specific? */
1169 len = offsetof(struct sockaddr_un, sun_path) + 1
1170 + snprintf(sa_un.sun_path+1, sizeof(sa_un.sun_path)-1, "%s",
1171 expand_string(notifier_socket));
1172 DEBUG(D_any) debug_printf(" @%s\n", sa_un.sun_path+1);
1173 #else /* filesystem-visible and persistent; will neeed removal */
1174 len = offsetof(struct sockaddr_un, sun_path)
1175 + snprintf(sa_un.sun_path, sizeof(sa_un.sun_path), "%s",
1176 expand_string(notifier_socket));
1177 DEBUG(D_any) debug_printf(" %s\n", sa_un.sun_path);
1180 if (bind(fd, (const struct sockaddr *)&sa_un, len) < 0)
1181 { where = US"bind"; goto bad; }
1183 #ifdef SO_PASSCRED /* Linux */
1184 if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0)
1185 { where = US"SO_PASSCRED"; goto bad2; }
1186 #elif defined(LOCAL_CREDS) /* FreeBSD-ish */
1187 if (setsockopt(fd, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
1188 { where = US"LOCAL_CREDS"; goto bad2; }
1191 /* debug_printf("%s: fd %d\n", __FUNCTION__, fd); */
1192 daemon_notifier_fd = fd;
1196 #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
1197 Uunlink(sa_un.sun_path);
1200 log_write(0, LOG_MAIN|LOG_PANIC, "%s %s: %s",
1201 __FUNCTION__, where, strerror(errno));
1207 static uschar queuerun_msgid[MESSAGE_ID_LENGTH+1];
1209 /* Return TRUE if a sigalrm should be emulated */
1211 daemon_notification(void)
1213 uschar buf[256], cbuf[256];
1214 struct sockaddr_un sa_un;
1215 struct iovec iov = {.iov_base = buf, .iov_len = sizeof(buf)-1};
1216 struct msghdr msg = { .msg_name = &sa_un,
1217 .msg_namelen = sizeof(sa_un),
1220 .msg_control = cbuf,
1221 .msg_controllen = sizeof(cbuf)
1225 buf[sizeof(buf)-1] = 0;
1226 if ((sz = recvmsg(daemon_notifier_fd, &msg, 0)) <= 0) return FALSE;
1227 if (sz >= sizeof(buf)) return FALSE;
1230 debug_printf("addrlen %d\n", msg.msg_namelen);
1232 DEBUG(D_queue_run) debug_printf("%s from addr '%s%.*s'\n", __FUNCTION__,
1233 *sa_un.sun_path ? "" : "@",
1234 (int)msg.msg_namelen - (*sa_un.sun_path ? 0 : 1),
1235 sa_un.sun_path + (*sa_un.sun_path ? 0 : 1));
1237 /* Refuse to handle the item unless the peer has good credentials */
1238 #ifdef SCM_CREDENTIALS
1239 # define EXIM_SCM_CR_TYPE SCM_CREDENTIALS
1240 #elif defined(LOCAL_CREDS) && defined(SCM_CREDS)
1241 # define EXIM_SCM_CR_TYPE SCM_CREDS
1243 /* The OS has no way to get the creds of the caller (for a unix/datagram socket.
1244 Punt; don't try to check. */
1247 #ifdef EXIM_SCM_CR_TYPE
1248 for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg);
1250 cp = CMSG_NXTHDR(&msg, cp))
1251 if (cp->cmsg_level == SOL_SOCKET && cp->cmsg_type == EXIM_SCM_CR_TYPE)
1253 # ifdef SCM_CREDENTIALS /* Linux */
1254 struct ucred * cr = (struct ucred *) CMSG_DATA(cp);
1255 if (cr->uid && cr->uid != exim_uid)
1257 DEBUG(D_queue_run) debug_printf("%s: sender creds pid %d uid %d gid %d\n",
1258 __FUNCTION__, (int)cr->pid, (int)cr->uid, (int)cr->gid);
1261 # elif defined(LOCAL_CREDS) /* BSD-ish */
1262 struct sockcred * cr = (struct sockcred *) CMSG_DATA(cp);
1263 if (cr->sc_uid && cr->sc_uid != exim_uid)
1265 DEBUG(D_queue_run) debug_printf("%s: sender creds pid ??? uid %d gid %d\n",
1266 __FUNCTION__, (int)cr->sc_uid, (int)cr->sc_gid);
1277 #ifndef DISABLE_QUEUE_RAMP
1278 case NOTIFY_MSG_QRUN:
1279 /* this should be a message_id */
1281 debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1);
1282 memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1);
1286 case NOTIFY_QUEUE_SIZE_REQ:
1289 int len = snprintf(CS buf, sizeof(buf), "%u", queue_count_cached());
1292 debug_printf("%s: queue size request: %s\n", __FUNCTION__, buf);
1294 if (sendto(daemon_notifier_fd, buf, len, 0,
1295 (const struct sockaddr *)&sa_un, msg.msg_namelen) < 0)
1296 log_write(0, LOG_MAIN|LOG_PANIC,
1297 "%s: sendto: %s\n", __FUNCTION__, strerror(errno));
1305 /*************************************************
1306 * Exim Daemon Mainline *
1307 *************************************************/
1309 /* The daemon can do two jobs, either of which is optional:
1311 (1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1312 each one. This is requested by the -bd option, with -oX specifying the SMTP
1313 port on which to listen (for testing).
1315 (2) Spawns a queue-running process every so often. This is controlled by the
1316 -q option with a an interval time. (If no time is given, a single queue run
1317 is done from the main function, and control doesn't get here.)
1319 Root privilege is required in order to attach to port 25. Some systems require
1320 it when calling socket() rather than bind(). To cope with all cases, we run as
1321 root for both socket() and bind(). Some systems also require root in order to
1322 write to the pid file directory. This function must therefore be called as root
1323 if it is to work properly in all circumstances. Once the socket is bound and
1324 the pid file written, root privilege is given up if there is an exim uid.
1326 There are no arguments to this function, and it never returns. */
1332 int *listen_sockets = NULL;
1333 int listen_socket_count = 0;
1334 ip_address_item *addresses = NULL;
1335 time_t last_connection_time = (time_t)0;
1336 int local_queue_run_max = atoi(CS expand_string(queue_run_max));
1338 process_purpose = US"daemon";
1340 /* If any debugging options are set, turn on the D_pid bit so that all
1341 debugging lines get the pid added. */
1343 DEBUG(D_any|D_v) debug_selector |= D_pid;
1345 if (f.inetd_wait_mode)
1347 listen_socket_count = 1;
1348 listen_sockets = store_get(sizeof(int), FALSE);
1350 if (dup2(0, 3) == -1)
1351 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1352 "failed to dup inetd socket safely away: %s", strerror(errno));
1354 listen_sockets[0] = 3;
1360 if (debug_file == stderr)
1362 /* need a call to log_write before call to open debug_file, so that
1363 log.c:file_path has been initialised. This is unfortunate. */
1364 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1368 exim_nullstd(); /* re-open fd2 after we just closed it again */
1369 debug_logging_activate(US"-wait", NULL);
1372 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1374 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1375 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1378 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1379 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1384 if (f.inetd_wait_mode || f.daemon_listen)
1386 /* If any option requiring a load average to be available during the
1387 reception of a message is set, call os_getloadavg() while we are root
1388 for those OS for which this is necessary the first time it is called (in
1389 order to perform an "open" on the kernel memory file). */
1391 #ifdef LOAD_AVG_NEEDS_ROOT
1392 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1393 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1394 (void)os_getloadavg();
1399 /* Do the preparation for setting up a listener on one or more interfaces, and
1400 possible on various ports. This is controlled by the combination of
1401 local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1402 (which is a list of default ports to use for those items in local_interfaces
1403 that do not specify a port). The -oX command line option can be used to
1404 override one or both of these options.
1406 If local_interfaces is not set, the default is to listen on all interfaces.
1407 When it is set, it can include "all IPvx interfaces" as an item. This is useful
1408 when different ports are in use.
1410 It turns out that listening on all interfaces is messy in an IPv6 world,
1411 because several different implementation approaches have been taken. This code
1412 is now supposed to work with all of them. The point of difference is whether an
1413 IPv6 socket that is listening on all interfaces will receive incoming IPv4
1414 calls or not. We also have to cope with the case when IPv6 libraries exist, but
1415 there is no IPv6 support in the kernel.
1417 . On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1418 addresses. However, if an IPv4 socket is also listening on all interfaces,
1419 calls are directed to the appropriate socket.
1421 . On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1422 give them as mapped addresses, but an attempt also to listen on an IPv4
1423 socket on all interfaces causes an error.
1425 . On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1426 two sockets if you want to accept both kinds of call.
1428 . FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1429 can be turned off, to make it behave like the versions of Linux described
1432 . I heard a report that the USAGI IPv6 stack for Linux has implemented
1435 So, what we do when IPv6 is supported is as follows:
1437 (1) After it is set up, the list of interfaces is scanned for wildcard
1438 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1439 port, the list is re-arranged so that they are together, with the IPv6
1442 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1443 carry on if an IPv4 wildcard socket for the same port follows later in the
1444 list. This allows Exim to carry on in the case when the kernel has no IPv6
1447 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1448 option is defined. However, if setting fails, carry on regardless (but log
1451 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1454 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1455 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1456 port (which must have succeeded or we wouldn't have got this far), we
1457 assume we are in the situation where just a single socket is permitted,
1458 and ignore the error.
1462 The preparation code decodes options and sets up the relevant data. We do this
1463 first, so that we can return non-zero if there are any syntax errors, and also
1466 if (f.daemon_listen && !f.inetd_wait_mode)
1468 int *default_smtp_port;
1472 const uschar * list;
1473 uschar *local_iface_source = US"local_interfaces";
1474 ip_address_item *ipa;
1475 ip_address_item **pipa;
1477 /* If -oX was used, disable the writing of a pid file unless -oP was
1478 explicitly used to force it. Then scan the string given to -oX. Any items
1479 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1480 Any other items are used to override local_interfaces. */
1482 if (override_local_interfaces)
1484 gstring * new_smtp_port = NULL;
1485 gstring * new_local_interfaces = NULL;
1487 if (!override_pid_file_path) write_pid = FALSE;
1489 list = override_local_interfaces;
1491 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
1494 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
1500 *gp = string_catn(*gp, US"<", 1);
1503 *gp = string_catn(*gp, joinstr, 2);
1504 *gp = string_cat (*gp, s);
1509 daemon_smtp_port = string_from_gstring(new_smtp_port);
1510 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1514 if (new_local_interfaces)
1516 local_interfaces = string_from_gstring(new_local_interfaces);
1517 local_iface_source = US"-oX data";
1518 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1523 /* Create a list of default SMTP ports, to be used if local_interfaces
1524 contains entries without explicit ports. First count the number of ports, then
1525 build a translated list in a vector. */
1527 list = daemon_smtp_port;
1529 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
1531 default_smtp_port = store_get((pct+1) * sizeof(int), FALSE);
1532 list = daemon_smtp_port;
1535 (s = string_nextinlist(&list, &sep, NULL, 0));
1541 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1542 if (end != s + Ustrlen(s))
1543 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1547 struct servent *smtp_service = getservbyname(CS s, "tcp");
1549 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1550 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1553 default_smtp_port[pct] = 0;
1555 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1557 list = tls_in.on_connect_ports;
1559 /* the list isn't expanded so cannot be tainted. If it ever is we will trap here */
1560 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1565 list = tls_in.on_connect_ports;
1566 tls_in.on_connect_ports = NULL;
1568 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1572 struct servent * smtp_service = getservbyname(CS s, "tcp");
1574 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1575 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
1577 g = string_append_listele(g, ':', s);
1580 tls_in.on_connect_ports = g->s;
1584 /* Create the list of local interfaces, possibly with ports included. This
1585 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1586 values are converted below. */
1588 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1590 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1591 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1592 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1593 anyway, but we need to know which are the wildcard addresses, and the shorter
1596 In the same scan, fill in missing port numbers from the default list. When
1597 there is more than one item in the list, extra items are created. */
1599 for (ipa = addresses; ipa; ipa = ipa->next)
1601 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1602 ipa->address[0] = 0;
1603 else if (Ustrcmp(ipa->address, "::0") == 0)
1605 ipa->address[0] = ':';
1606 ipa->address[1] = 0;
1609 if (ipa->port > 0) continue;
1611 if (daemon_smtp_port[0] <= 0)
1612 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1613 "%s and daemon_smtp_port is unset; cannot start daemon",
1614 ipa->address[0] == 0 ? US"\"all IPv4\"" :
1615 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
1617 ipa->port = default_smtp_port[0];
1618 for (int i = 1; default_smtp_port[i] > 0; i++)
1620 ip_address_item *new = store_get(sizeof(ip_address_item), FALSE);
1622 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1623 new->port = default_smtp_port[i];
1624 new->next = ipa->next;
1630 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1631 wildcard for the same port, ensure that (a) they are together and (b) the
1632 IPv6 address comes first. This makes handling the messy features easier, and
1633 also simplifies the construction of the "daemon started" log line. */
1636 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
1638 ip_address_item *ipa2;
1640 /* Handle an IPv4 wildcard */
1642 if (ipa->address[0] == 0)
1643 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1645 ip_address_item *ipa3 = ipa2->next;
1646 if (ipa3->address[0] == ':' &&
1647 ipa3->address[1] == 0 &&
1648 ipa3->port == ipa->port)
1650 ipa2->next = ipa3->next;
1657 /* Handle an IPv6 wildcard. */
1659 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
1660 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1662 ip_address_item *ipa3 = ipa2->next;
1663 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1665 ipa2->next = ipa3->next;
1666 ipa3->next = ipa->next;
1674 /* Get a vector to remember all the sockets in */
1676 for (ipa = addresses; ipa; ipa = ipa->next)
1677 listen_socket_count++;
1678 listen_sockets = store_get(sizeof(int) * listen_socket_count, FALSE);
1680 } /* daemon_listen but not inetd_wait_mode */
1682 if (f.daemon_listen)
1685 /* Do a sanity check on the max connects value just to save us from getting
1686 a huge amount of store. */
1688 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1690 /* There's no point setting smtp_accept_queue unless it is less than the max
1691 connects limit. The configuration reader ensures that the max is set if the
1692 queue-only option is set. */
1694 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1696 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1697 track of them for total number and queue/host limits. */
1699 if (smtp_accept_max > 0)
1701 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), FALSE);
1702 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
1706 /* The variable background_daemon is always false when debugging, but
1707 can also be forced false in order to keep a non-debugging daemon in the
1708 foreground. If background_daemon is true, close all open file descriptors that
1709 we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1710 do this for inetd_wait mode.
1712 This is protection against any called functions (in libraries, or in
1713 Perl, or whatever) that think they can write to stderr (or stdout). Before this
1714 was added, it was quite likely that an SMTP connection would use one of these
1715 file descriptors, in which case writing random stuff to it caused chaos.
1717 Then disconnect from the controlling terminal, Most modern Unixes seem to have
1718 setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1719 setsid() can be #defined as a no-op, or as something else. */
1721 if (f.background_daemon || f.inetd_wait_mode)
1723 log_close_all(); /* Just in case anything was logged earlier */
1724 search_tidyup(); /* Just in case any were used in reading the config. */
1725 (void)close(0); /* Get rid of stdin/stdout/stderr */
1728 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
1729 log_stderr = NULL; /* So no attempt to copy paniclog output */
1732 if (f.background_daemon)
1734 /* If the parent process of this one has pid == 1, we are re-initializing the
1735 daemon as the result of a SIGHUP. In this case, there is no need to do
1736 anything, because the controlling terminal has long gone. Otherwise, fork, in
1737 case current process is a process group leader (see 'man setsid' for an
1738 explanation) before calling setsid(). */
1742 pid_t pid = exim_fork(US"daemon");
1743 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1744 "fork() failed when starting daemon: %s", strerror(errno));
1745 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1746 (void)setsid(); /* release controlling terminal */
1750 /* We are now in the disconnected, daemon process (unless debugging). Set up
1751 the listening sockets if required. */
1753 daemon_notifier_socket();
1755 if (f.daemon_listen && !f.inetd_wait_mode)
1758 ip_address_item *ipa;
1760 /* For each IP address, create a socket, bind it to the appropriate port, and
1761 start listening. See comments above about IPv6 sockets that may or may not
1762 accept IPv4 calls when listening on all interfaces. We also have to cope with
1763 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1764 listening, provided a wildcard IPv4 socket for the same port follows. */
1766 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1769 ip_address_item *ipa2;
1772 if (Ustrchr(ipa->address, ':') != NULL)
1775 wildcard = ipa->address[1] == 0;
1780 wildcard = ipa->address[0] == 0;
1783 if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0)
1785 if (check_special_case(0, addresses, ipa, FALSE))
1787 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1788 "listening (%s): will use IPv4", strerror(errno));
1791 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1792 (af == AF_INET6)? '6' : '4', strerror(errno));
1795 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1796 available. Just log failure (can get protocol not available, just like
1797 socket creation can). */
1800 if (af == AF_INET6 && wildcard &&
1801 setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, CS (&on),
1803 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1804 "socket failed (%s): carrying on without it", strerror(errno));
1805 #endif /* IPV6_V6ONLY */
1807 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1808 is being handled. Without this, a connection will prevent reuse of the
1809 smtp port for listening. */
1811 if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR,
1812 US (&on), sizeof(on)) < 0)
1813 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1814 "failed when starting daemon: %s", strerror(errno));
1816 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1817 disable this because it breaks some broken clients. */
1819 if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY,
1820 US (&on), sizeof(on));
1822 /* Now bind the socket to the required port; if Exim is being restarted
1823 it may not always be possible to bind immediately, even with SO_REUSEADDR
1824 set, so try 10 times, waiting between each try. After 10 failures, we give
1825 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1826 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1827 address for the same port, ignore the error on the grounds that we must be
1828 in a system where the IPv6 socket accepts both kinds of call. This is
1829 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1830 listen() stage instead. */
1833 f.tcp_fastopen_ok = TRUE;
1838 if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break;
1839 if (check_special_case(errno, addresses, ipa, TRUE))
1841 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1842 "listen() success; EADDRINUSE ignored\n");
1843 (void)close(listen_sockets[sk]);
1846 msg = US strerror(errno);
1852 if (daemon_startup_retries <= 0)
1853 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1854 "socket bind() to port %d for address %s failed: %s: "
1855 "daemon abandoned", ipa->port, addr, msg);
1856 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
1857 "failed: %s: waiting %s before trying again (%d more %s)",
1858 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1859 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1860 daemon_startup_retries--;
1861 sleep(daemon_startup_sleep);
1866 debug_printf("listening on all interfaces (IPv%c) port %d\n",
1867 af == AF_INET6 ? '6' : '4', ipa->port);
1869 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
1871 #if defined(TCP_FASTOPEN) && !defined(__APPLE__)
1872 if ( f.tcp_fastopen_ok
1873 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1874 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
1876 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1877 f.tcp_fastopen_ok = FALSE;
1881 /* Start listening on the bound socket, establishing the maximum backlog of
1882 connections that is allowed. On success, continue to the next address. */
1884 if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0)
1886 #if defined(TCP_FASTOPEN) && defined(__APPLE__)
1887 if ( f.tcp_fastopen_ok
1888 && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN,
1891 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1892 f.tcp_fastopen_ok = FALSE;
1898 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1899 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1900 and there was a previous successful IPv6 wildcard listen on the same port,
1901 we want to ignore the error on the grounds that we must be in a system
1902 where the IPv6 socket accepts both kinds of call. */
1904 if (!check_special_case(errno, addresses, ipa, TRUE))
1905 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
1907 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
1910 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1911 "listen() success; EADDRINUSE ignored\n");
1912 (void)close(listen_sockets[sk]);
1914 /* Come here if there has been a problem with the socket which we
1915 are going to ignore. We remove the address from the chain, and back up the
1919 sk--; /* Back up the count */
1920 listen_socket_count--; /* Reduce the total */
1921 if (ipa == addresses) addresses = ipa->next; else
1923 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1924 ipa2->next = ipa->next;
1927 } /* End of bind/listen loop for each address */
1928 } /* End of setup for listening */
1931 /* If we are not listening, we want to write a pid file only if -oP was
1932 explicitly given. */
1934 else if (!override_pid_file_path)
1937 /* Write the pid to a known file for assistance in identification, if required.
1938 We do this before giving up root privilege, because on some systems it is
1939 necessary to be root in order to write into the pid file directory. There's
1940 nothing to stop multiple daemons running, as long as no more than one listens
1941 on a given TCP/IP port on the same interface(s). However, in these
1942 circumstances it gets far too complicated to mess with pid file names
1943 automatically. Consequently, Exim 4 writes a pid file only
1945 (a) When running in the test harness, or
1946 (b) When -bd is used and -oX is not used, or
1947 (c) When -oP is used to supply a path.
1949 The variable daemon_write_pid is used to control this. */
1951 if (f.running_in_test_harness || write_pid)
1953 const enum pid_op operation = (f.running_in_test_harness
1954 || real_uid == root_uid
1955 || (real_uid == exim_uid && !override_pid_file_path)) ? PID_WRITE : PID_CHECK;
1956 if (!operate_on_pid_file(operation, getpid()))
1957 DEBUG(D_any) debug_printf("%s pid file %s: %s\n", (operation == PID_WRITE) ? "write" : "check", pid_file_path, strerror(errno));
1960 /* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1961 sighup_seen = FALSE;
1962 signal(SIGHUP, sighup_handler);
1964 /* Give up root privilege at this point (assuming that exim_uid and exim_gid
1965 are not root). The third argument controls the running of initgroups().
1966 Normally we do this, in order to set up the groups for the Exim user. However,
1967 if we are not root at this time - some odd installations run that way - we
1970 exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1972 /* Update the originator_xxx fields so that received messages as listed as
1973 coming from Exim, not whoever started the daemon. */
1975 originator_uid = exim_uid;
1976 originator_gid = exim_gid;
1977 originator_login = (pw = getpwuid(exim_uid))
1978 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
1980 /* Get somewhere to keep the list of queue-runner pids if we are keeping track
1981 of them (and also if we are doing queue runs). */
1983 if (queue_interval > 0 && local_queue_run_max > 0)
1985 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t), FALSE);
1986 for (int i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
1989 /* Set up the handler for termination of child processes, and the one
1990 telling us to die. */
1992 sigchld_seen = FALSE;
1993 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
1995 sigterm_seen = FALSE;
1996 os_non_restarting_signal(SIGTERM, main_sigterm_handler);
1997 os_non_restarting_signal(SIGINT, main_sigterm_handler);
1999 /* If we are to run the queue periodically, pretend the alarm has just gone
2000 off. This will cause the first queue-runner to get kicked off straight away. */
2002 sigalrm_seen = (queue_interval > 0);
2004 /* Log the start up of a daemon - at least one of listening or queue running
2007 if (f.inetd_wait_mode)
2009 uschar *p = big_buffer;
2011 if (inetd_wait_timeout >= 0)
2012 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
2014 sprintf(CS p, "with no wait timeout");
2016 log_write(0, LOG_MAIN,
2017 "exim %s daemon started: pid=%d, launched with listening socket, %s",
2018 version_string, getpid(), big_buffer);
2019 set_process_info("daemon(%s): pre-listening socket", version_string);
2021 /* set up the timeout logic */
2022 sigalrm_seen = TRUE;
2025 else if (f.daemon_listen)
2028 int smtps_ports = 0;
2029 ip_address_item * ipa;
2031 uschar * qinfo = queue_interval > 0
2032 ? string_sprintf("-q%s%s",
2033 f.queue_2stage ? "q" : "", readconf_printtime(queue_interval))
2034 : US"no queue runs";
2036 /* Build a list of listening addresses in big_buffer, but limit it to 10
2037 items. The style is for backwards compatibility.
2039 It is now possible to have some ports listening for SMTPS (the old,
2040 deprecated protocol that starts TLS without using STARTTLS), and others
2041 listening for standard SMTP. Keep their listings separate. */
2043 for (int j = 0, i; j < 2; j++)
2045 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
2047 /* First time round, look for SMTP ports; second time round, look for
2048 SMTPS ports. Build IP+port strings. */
2050 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
2057 /* Now the information about the port (and sometimes interface) */
2059 if (ipa->address[0] == ':' && ipa->address[1] == 0)
2061 if (ipa->next && ipa->next->address[0] == 0 &&
2062 ipa->next->port == ipa->port)
2064 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
2065 (ipa = ipa->next)->log = NULL;
2067 else if (ipa->v6_include_v4)
2068 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
2070 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
2072 else if (ipa->address[0] == 0) /* v4 wildcard */
2073 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
2074 else /* check for previously-seen IP */
2076 ip_address_item * i2;
2077 for (i2 = addresses; i2 != ipa; i2 = i2->next)
2078 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
2079 && Ustrcmp(ipa->address, i2->address) == 0
2081 { /* found; append port to list */
2082 for (p = i2->log; *p; ) p++; /* end of existing string */
2083 if (*--p == '}') *p = '\0'; /* drop EOL */
2084 while (isdigit(*--p)) ; /* char before port */
2086 i2->log = *p == ':' /* no list yet? */
2087 ? string_sprintf("%.*s{%s,%d}",
2088 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
2089 : string_sprintf("%s,%d}", i2->log, ipa->port);
2093 if (i2 == ipa) /* first-time IP */
2094 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
2101 for (int j = 0, i; j < 2; j++)
2103 /* First time round, look for SMTP ports; second time round, look for
2104 SMTPS ports. For the first one of each, insert leading text. */
2109 p += sprintf(CS p, "SMTP on");
2112 if (smtps_ports > 0)
2113 p += sprintf(CS p, "%sSMTPS on",
2114 smtp_ports == 0 ? "" : " and for ");
2116 /* Now the information about the port (and sometimes interface) */
2118 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
2119 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
2121 p += sprintf(CS p, "%s", ipa->log);
2124 p += sprintf(CS p, " ...");
2127 log_write(0, LOG_MAIN,
2128 "exim %s daemon started: pid=%d, %s, listening for %s",
2129 version_string, getpid(), qinfo, big_buffer);
2130 set_process_info("daemon(%s): %s, listening for %s",
2131 version_string, qinfo, big_buffer);
2136 uschar * s = *queue_name
2137 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
2138 : string_sprintf("-q%s", readconf_printtime(queue_interval));
2139 log_write(0, LOG_MAIN,
2140 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
2141 version_string, getpid(), s);
2142 set_process_info("daemon(%s): %s, not listening", version_string, s);
2145 /* Do any work it might be useful to amortize over our children
2146 (eg: compile regex) */
2149 smtp_deliver_init(); /* Used for callouts */
2151 #ifndef DISABLE_DKIM
2153 # ifdef MEASURE_TIMING
2155 gettimeofday(&t0, NULL);
2158 # ifdef MEASURE_TIMING
2159 report_time_since(&t0, US"dkim_exim_init (delta)");
2164 #ifdef WITH_CONTENT_SCAN
2174 /* Close the log so it can be renamed and moved. In the few cases below where
2175 this long-running process writes to the log (always exceptional conditions), it
2176 closes the log afterwards, for the same reason. */
2180 DEBUG(D_any) debug_print_ids(US"daemon running with");
2182 /* Any messages accepted via this route are going to be SMTP. */
2186 #ifdef MEASURE_TIMING
2187 report_time_since(×tamp_startup, US"daemon loop start"); /* testcase 0022 */
2190 /* Enter the never-ending loop... */
2195 struct sockaddr_in6 accepted;
2197 struct sockaddr_in accepted;
2204 daemon_die(); /* Does not return */
2206 /* This code is placed first in the loop, so that it gets obeyed at the
2207 start, before the first wait, for the queue-runner case, so that the first
2208 one can be started immediately.
2210 The other option is that we have an inetd wait timeout specified to -bw. */
2214 if (inetd_wait_timeout > 0)
2216 time_t resignal_interval = inetd_wait_timeout;
2218 if (last_connection_time == (time_t)0)
2221 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
2225 time_t now = time(NULL);
2226 if (now == (time_t)-1)
2228 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
2232 if ((now - last_connection_time) >= inetd_wait_timeout)
2235 debug_printf("inetd wait timeout %d expired, ending daemon\n",
2236 inetd_wait_timeout);
2237 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
2243 resignal_interval -= (now - last_connection_time);
2248 sigalrm_seen = FALSE;
2249 ALARM(resignal_interval);
2254 DEBUG(D_any) debug_printf("%s received\n",
2255 #ifndef DISABLE_QUEUE_RAMP
2256 *queuerun_msgid ? "qrun notification" :
2260 /* Do a full queue run in a child process, if required, unless we already
2261 have enough queue runners on the go. If we are not running as root, a
2262 re-exec is required. */
2264 if ( queue_interval > 0
2265 && (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
2267 if ((pid = exim_fork(US"queue-runner")) == 0)
2269 /* Disable debugging if it's required only for the daemon process. We
2270 leave the above message, because it ties up with the "child ended"
2271 debugging messages. */
2273 if (f.debug_daemon) debug_selector = 0;
2275 /* Close any open listening sockets in the child */
2277 close_daemon_sockets(daemon_notifier_fd,
2278 listen_sockets, listen_socket_count);
2280 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
2282 signal(SIGHUP, SIG_DFL);
2283 signal(SIGCHLD, SIG_DFL);
2284 signal(SIGTERM, SIG_DFL);
2285 signal(SIGINT, SIG_DFL);
2287 /* Re-exec if privilege has been given up, unless deliver_drop_
2288 privilege is set. Reset SIGALRM before exec(). */
2290 if (geteuid() != root_uid && !deliver_drop_privilege)
2297 signal(SIGALRM, SIG_DFL);
2301 #ifndef DISABLE_QUEUE_RAMP
2305 if (f.queue_run_first_delivery) *p++ = 'i';
2306 if (f.queue_run_force) *p++ = 'f';
2307 if (f.deliver_force_thaw) *p++ = 'f';
2308 if (f.queue_run_local) *p++ = 'l';
2310 extra[0] = *queue_name
2311 ? string_sprintf("%sG%s", opt, queue_name) : opt;
2313 #ifndef DISABLE_QUEUE_RAMP
2314 if (*queuerun_msgid)
2316 log_write(0, LOG_MAIN, "notify triggered queue run");
2317 extra[extracount++] = queuerun_msgid; /* Trigger only the */
2318 extra[extracount++] = queuerun_msgid; /* one message */
2322 /* If -R or -S were on the original command line, ensure they get
2325 if (deliver_selectstring)
2327 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
2328 extra[extracount++] = deliver_selectstring;
2331 if (deliver_selectstring_sender)
2333 extra[extracount++] = f.deliver_selectstring_sender_regex
2335 extra[extracount++] = deliver_selectstring_sender;
2338 /* Overlay this process with a new execution. */
2340 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
2341 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
2343 /* Control never returns here. */
2346 /* No need to re-exec; SIGALRM remains set to the default handler */
2348 #ifndef DISABLE_QUEUE_RAMP
2349 if (*queuerun_msgid)
2351 log_write(0, LOG_MAIN, "notify triggered queue run");
2352 f.queue_2stage = FALSE;
2353 queue_run(queuerun_msgid, queuerun_msgid, FALSE);
2357 queue_run(NULL, NULL, FALSE);
2358 exim_underbar_exit(EXIT_SUCCESS);
2363 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
2364 "process failed: %s", strerror(errno));
2369 for (int i = 0; i < local_queue_run_max; ++i)
2370 if (queue_pid_slots[i] <= 0)
2372 queue_pid_slots[i] = pid;
2376 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
2377 queue_run_count, queue_run_count == 1 ? "" : "es");
2381 /* Reset the alarm clock */
2383 sigalrm_seen = FALSE;
2384 #ifndef DISABLE_QUEUE_RAMP
2385 if (*queuerun_msgid)
2386 *queuerun_msgid = 0;
2389 ALARM(queue_interval);
2392 } /* sigalrm_seen */
2395 /* Sleep till a connection happens if listening, and handle the connection if
2396 that is why we woke up. The FreeBSD operating system requires the use of
2397 select() before accept() because the latter function is not interrupted by
2398 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2399 OS do notice signals in accept() but it does no harm to have the select()
2400 in for all of them - and it won't then be a lurking problem for ports to
2401 new OS. In fact, the later addition of listening on specific interfaces only
2402 requires this way of working anyway. */
2404 if (f.daemon_listen)
2408 BOOL select_failed = FALSE;
2409 fd_set select_listen;
2411 FD_ZERO(&select_listen);
2413 if (tls_watch_fd >= 0)
2415 FD_SET(tls_watch_fd, &select_listen);
2416 if (tls_watch_fd > max_socket) max_socket = tls_watch_fd;
2419 if (daemon_notifier_fd >= 0)
2421 FD_SET(daemon_notifier_fd, &select_listen);
2422 if (daemon_notifier_fd > max_socket) max_socket = daemon_notifier_fd;
2424 for (int sk = 0; sk < listen_socket_count; sk++)
2426 FD_SET(listen_sockets[sk], &select_listen);
2427 if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk];
2430 DEBUG(D_any) debug_printf("Listening...\n");
2432 /* In rare cases we may have had a SIGCHLD signal in the time between
2433 setting the handler (below) and getting back here. If so, pretend that the
2434 select() was interrupted so that we reap the child. This might still leave
2435 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
2436 only to do the reaping more quickly, it shouldn't result in anything other
2437 than a delay until something else causes a wake-up. */
2445 lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen,
2450 select_failed = TRUE;
2454 /* Clean up any subprocesses that may have terminated. We need to do this
2455 here so that smtp_accept_max_per_host works when a connection to that host
2456 has completed, and we are about to accept a new one. When this code was
2457 later in the sequence, a new connection could be rejected, even though an
2458 old one had just finished. Preserve the errno from any select() failure for
2459 the use of the common select/accept error processing below. */
2462 int select_errno = errno;
2463 handle_ending_processes();
2466 /* Create or rotate any required keys; handle (delayed) filewatch event */
2469 errno = select_errno;
2472 /* Loop for all the sockets that are currently ready to go. If select
2473 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2474 to use the common error code for select/accept below. */
2476 while (lcount-- > 0)
2478 int accept_socket = -1;
2482 #if !defined(DISABLE_TLS) && (defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT))
2483 if (tls_watch_fd >= 0 && FD_ISSET(tls_watch_fd, &select_listen))
2485 FD_CLR(tls_watch_fd, &select_listen);
2486 tls_watch_trigger_time = time(NULL); /* Set up delayed event */
2487 tls_watch_discard_event(tls_watch_fd);
2488 break; /* to top of daemon loop */
2491 if ( daemon_notifier_fd >= 0
2492 && FD_ISSET(daemon_notifier_fd, &select_listen))
2494 FD_CLR(daemon_notifier_fd, &select_listen);
2495 sigalrm_seen = daemon_notification();
2496 break; /* to top of daemon loop */
2498 for (int sk = 0; sk < listen_socket_count; sk++)
2499 if (FD_ISSET(listen_sockets[sk], &select_listen))
2501 len = sizeof(accepted);
2502 accept_socket = accept(listen_sockets[sk],
2503 (struct sockaddr *)&accepted, &len);
2504 FD_CLR(listen_sockets[sk], &select_listen);
2509 /* If select or accept has failed and this was not caused by an
2510 interruption, log the incident and try again. With asymmetric TCP/IP
2511 routing errors such as "No route to network" have been seen here. Also
2512 "connection reset by peer" has been seen. These cannot be classed as
2513 disastrous errors, but they could fill up a lot of log. The code in smail
2514 crashes the daemon after 10 successive failures of accept, on the grounds
2515 that some OS fail continuously. Exim originally followed suit, but this
2516 appears to have caused problems. Now it just keeps going, but instead of
2517 logging each error, it batches them up when they are continuous. */
2519 if (accept_socket < 0 && errno != EINTR)
2521 if (accept_retry_count == 0)
2523 accept_retry_errno = errno;
2524 accept_retry_select_failed = select_failed;
2526 else if ( errno != accept_retry_errno
2527 || select_failed != accept_retry_select_failed
2528 || accept_retry_count >= 50)
2530 log_write(0, LOG_MAIN | (accept_retry_count >= 50 ? LOG_PANIC : 0),
2531 "%d %s() failure%s: %s",
2533 accept_retry_select_failed ? "select" : "accept",
2534 accept_retry_count == 1 ? "" : "s",
2535 strerror(accept_retry_errno));
2537 accept_retry_count = 0;
2538 accept_retry_errno = errno;
2539 accept_retry_select_failed = select_failed;
2541 accept_retry_count++;
2543 else if (accept_retry_count > 0)
2545 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2547 accept_retry_select_failed ? "select" : "accept",
2548 accept_retry_count == 1 ? "" : "s",
2549 strerror(accept_retry_errno));
2551 accept_retry_count = 0;
2554 /* If select/accept succeeded, deal with the connection. */
2556 if (accept_socket >= 0)
2558 #ifdef TCP_QUICKACK /* Avoid pure-ACKs while in tls protocol pingpong phase */
2559 /* Unfortunately we cannot be certain to do this before a TLS-on-connect
2560 Client Hello arrives and is acked. We do it as early as possible. */
2561 (void) setsockopt(accept_socket, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
2563 if (inetd_wait_timeout)
2564 last_connection_time = time(NULL);
2565 handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,
2566 (struct sockaddr *)&accepted);
2571 /* If not listening, then just sleep for the queue interval. If we woke
2572 up early the last time for some other signal, it won't matter because
2573 the alarm signal will wake at the right time. This code originally used
2574 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2575 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2576 select() can be used as an interruptible sleep() on all versions of Unix. */
2581 tv.tv_sec = queue_interval;
2583 select(0, NULL, NULL, NULL, &tv);
2584 handle_ending_processes();
2587 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2588 for itself, because it isn't doing the waiting itself. */
2592 sigchld_seen = FALSE;
2593 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
2596 /* Handle being woken by SIGHUP. We know at this point that the result
2597 of accept() has been dealt with, so we can re-exec exim safely, first
2598 closing the listening sockets so that they can be reused. Cancel any pending
2599 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2600 that another HUP in quick succession doesn't clobber the new daemon before it
2601 gets going. All log files get closed by the close-on-exec flag; however, if
2602 the exec fails, we need to close the logs. */
2606 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2608 close_daemon_sockets(daemon_notifier_fd,
2609 listen_sockets, listen_socket_count);
2611 signal(SIGHUP, SIG_IGN);
2612 sighup_argv[0] = exim_path;
2614 execv(CS exim_path, (char *const *)sighup_argv);
2615 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2616 getpid(), exim_path, strerror(errno));
2620 } /* End of main loop */
2622 /* Control never reaches here */
2627 /* End of exim_daemon.c */