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));
1302 add_listener_socket(int fd, fd_set * fds, int * fd_max)
1305 if (fd > *fd_max) *fd_max = fd;
1308 /*************************************************
1309 * Exim Daemon Mainline *
1310 *************************************************/
1312 /* The daemon can do two jobs, either of which is optional:
1314 (1) Listens for incoming SMTP calls and spawns off a sub-process to handle
1315 each one. This is requested by the -bd option, with -oX specifying the SMTP
1316 port on which to listen (for testing).
1318 (2) Spawns a queue-running process every so often. This is controlled by the
1319 -q option with a an interval time. (If no time is given, a single queue run
1320 is done from the main function, and control doesn't get here.)
1322 Root privilege is required in order to attach to port 25. Some systems require
1323 it when calling socket() rather than bind(). To cope with all cases, we run as
1324 root for both socket() and bind(). Some systems also require root in order to
1325 write to the pid file directory. This function must therefore be called as root
1326 if it is to work properly in all circumstances. Once the socket is bound and
1327 the pid file written, root privilege is given up if there is an exim uid.
1329 There are no arguments to this function, and it never returns. */
1335 int * listen_sockets = NULL;
1336 int listen_socket_count = 0, listen_fd_max = 0;
1337 fd_set select_listen;
1338 ip_address_item * addresses = NULL;
1339 time_t last_connection_time = (time_t)0;
1340 int local_queue_run_max = atoi(CS expand_string(queue_run_max));
1342 process_purpose = US"daemon";
1344 /* If any debugging options are set, turn on the D_pid bit so that all
1345 debugging lines get the pid added. */
1347 DEBUG(D_any|D_v) debug_selector |= D_pid;
1349 FD_ZERO(&select_listen);
1350 if (f.inetd_wait_mode)
1352 listen_socket_count = 1;
1353 listen_sockets = store_get(sizeof(int), FALSE);
1355 if (dup2(0, 3) == -1)
1356 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1357 "failed to dup inetd socket safely away: %s", strerror(errno));
1359 listen_sockets[0] = 3;
1365 if (debug_file == stderr)
1367 /* need a call to log_write before call to open debug_file, so that
1368 log.c:file_path has been initialised. This is unfortunate. */
1369 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
1373 exim_nullstd(); /* re-open fd2 after we just closed it again */
1374 debug_logging_activate(US"-wait", NULL);
1377 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
1379 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
1380 our own buffering; we assume though that inetd set the socket REUSEADDR. */
1383 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
1384 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
1387 FD_SET(3, &select_listen);
1392 if (f.inetd_wait_mode || f.daemon_listen)
1394 /* If any option requiring a load average to be available during the
1395 reception of a message is set, call os_getloadavg() while we are root
1396 for those OS for which this is necessary the first time it is called (in
1397 order to perform an "open" on the kernel memory file). */
1399 #ifdef LOAD_AVG_NEEDS_ROOT
1400 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
1401 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
1402 (void)os_getloadavg();
1407 /* Do the preparation for setting up a listener on one or more interfaces, and
1408 possible on various ports. This is controlled by the combination of
1409 local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
1410 (which is a list of default ports to use for those items in local_interfaces
1411 that do not specify a port). The -oX command line option can be used to
1412 override one or both of these options.
1414 If local_interfaces is not set, the default is to listen on all interfaces.
1415 When it is set, it can include "all IPvx interfaces" as an item. This is useful
1416 when different ports are in use.
1418 It turns out that listening on all interfaces is messy in an IPv6 world,
1419 because several different implementation approaches have been taken. This code
1420 is now supposed to work with all of them. The point of difference is whether an
1421 IPv6 socket that is listening on all interfaces will receive incoming IPv4
1422 calls or not. We also have to cope with the case when IPv6 libraries exist, but
1423 there is no IPv6 support in the kernel.
1425 . On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
1426 addresses. However, if an IPv4 socket is also listening on all interfaces,
1427 calls are directed to the appropriate socket.
1429 . On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
1430 give them as mapped addresses, but an attempt also to listen on an IPv4
1431 socket on all interfaces causes an error.
1433 . On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
1434 two sockets if you want to accept both kinds of call.
1436 . FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1437 can be turned off, to make it behave like the versions of Linux described
1440 . I heard a report that the USAGI IPv6 stack for Linux has implemented
1443 So, what we do when IPv6 is supported is as follows:
1445 (1) After it is set up, the list of interfaces is scanned for wildcard
1446 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1447 port, the list is re-arranged so that they are together, with the IPv6
1450 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1451 carry on if an IPv4 wildcard socket for the same port follows later in the
1452 list. This allows Exim to carry on in the case when the kernel has no IPv6
1455 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1456 option is defined. However, if setting fails, carry on regardless (but log
1459 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1462 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1463 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1464 port (which must have succeeded or we wouldn't have got this far), we
1465 assume we are in the situation where just a single socket is permitted,
1466 and ignore the error.
1470 The preparation code decodes options and sets up the relevant data. We do this
1471 first, so that we can return non-zero if there are any syntax errors, and also
1474 if (f.daemon_listen && !f.inetd_wait_mode)
1476 int *default_smtp_port;
1480 const uschar * list;
1481 uschar *local_iface_source = US"local_interfaces";
1482 ip_address_item *ipa;
1483 ip_address_item **pipa;
1485 /* If -oX was used, disable the writing of a pid file unless -oP was
1486 explicitly used to force it. Then scan the string given to -oX. Any items
1487 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1488 Any other items are used to override local_interfaces. */
1490 if (override_local_interfaces)
1492 gstring * new_smtp_port = NULL;
1493 gstring * new_local_interfaces = NULL;
1495 if (!override_pid_file_path) write_pid = FALSE;
1497 list = override_local_interfaces;
1499 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
1502 gstring ** gp = Ustrpbrk(s, ".:") ? &new_local_interfaces : &new_smtp_port;
1508 *gp = string_catn(*gp, US"<", 1);
1511 *gp = string_catn(*gp, joinstr, 2);
1512 *gp = string_cat (*gp, s);
1517 daemon_smtp_port = string_from_gstring(new_smtp_port);
1518 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1522 if (new_local_interfaces)
1524 local_interfaces = string_from_gstring(new_local_interfaces);
1525 local_iface_source = US"-oX data";
1526 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1531 /* Create a list of default SMTP ports, to be used if local_interfaces
1532 contains entries without explicit ports. First count the number of ports, then
1533 build a translated list in a vector. */
1535 list = daemon_smtp_port;
1537 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
1539 default_smtp_port = store_get((pct+1) * sizeof(int), FALSE);
1540 list = daemon_smtp_port;
1543 (s = string_nextinlist(&list, &sep, NULL, 0));
1549 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1550 if (end != s + Ustrlen(s))
1551 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1555 struct servent *smtp_service = getservbyname(CS s, "tcp");
1557 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1558 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1561 default_smtp_port[pct] = 0;
1563 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1565 list = tls_in.on_connect_ports;
1567 /* the list isn't expanded so cannot be tainted. If it ever is we will trap here */
1568 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1573 list = tls_in.on_connect_ports;
1574 tls_in.on_connect_ports = NULL;
1576 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1580 struct servent * smtp_service = getservbyname(CS s, "tcp");
1582 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1583 s = string_sprintf("%d", (int)ntohs(smtp_service->s_port));
1585 g = string_append_listele(g, ':', s);
1588 tls_in.on_connect_ports = g->s;
1592 /* Create the list of local interfaces, possibly with ports included. This
1593 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1594 values are converted below. */
1596 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1598 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1599 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1600 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1601 anyway, but we need to know which are the wildcard addresses, and the shorter
1604 In the same scan, fill in missing port numbers from the default list. When
1605 there is more than one item in the list, extra items are created. */
1607 for (ipa = addresses; ipa; ipa = ipa->next)
1609 if (Ustrcmp(ipa->address, "0.0.0.0") == 0)
1610 ipa->address[0] = 0;
1611 else if (Ustrcmp(ipa->address, "::0") == 0)
1613 ipa->address[0] = ':';
1614 ipa->address[1] = 0;
1617 if (ipa->port > 0) continue;
1619 if (daemon_smtp_port[0] <= 0)
1620 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1621 "%s and daemon_smtp_port is unset; cannot start daemon",
1622 ipa->address[0] == 0 ? US"\"all IPv4\"" :
1623 ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address);
1625 ipa->port = default_smtp_port[0];
1626 for (int i = 1; default_smtp_port[i] > 0; i++)
1628 ip_address_item *new = store_get(sizeof(ip_address_item), FALSE);
1630 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1631 new->port = default_smtp_port[i];
1632 new->next = ipa->next;
1638 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1639 wildcard for the same port, ensure that (a) they are together and (b) the
1640 IPv6 address comes first. This makes handling the messy features easier, and
1641 also simplifies the construction of the "daemon started" log line. */
1644 for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next)
1646 ip_address_item *ipa2;
1648 /* Handle an IPv4 wildcard */
1650 if (ipa->address[0] == 0)
1651 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1653 ip_address_item *ipa3 = ipa2->next;
1654 if (ipa3->address[0] == ':' &&
1655 ipa3->address[1] == 0 &&
1656 ipa3->port == ipa->port)
1658 ipa2->next = ipa3->next;
1665 /* Handle an IPv6 wildcard. */
1667 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
1668 for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next)
1670 ip_address_item *ipa3 = ipa2->next;
1671 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1673 ipa2->next = ipa3->next;
1674 ipa3->next = ipa->next;
1682 /* Get a vector to remember all the sockets in */
1684 for (ipa = addresses; ipa; ipa = ipa->next)
1685 listen_socket_count++;
1686 listen_sockets = store_get(sizeof(int) * listen_socket_count, FALSE);
1688 } /* daemon_listen but not inetd_wait_mode */
1690 if (f.daemon_listen)
1693 /* Do a sanity check on the max connects value just to save us from getting
1694 a huge amount of store. */
1696 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1698 /* There's no point setting smtp_accept_queue unless it is less than the max
1699 connects limit. The configuration reader ensures that the max is set if the
1700 queue-only option is set. */
1702 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1704 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1705 track of them for total number and queue/host limits. */
1707 if (smtp_accept_max > 0)
1709 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot), FALSE);
1710 for (int i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
1714 /* The variable background_daemon is always false when debugging, but
1715 can also be forced false in order to keep a non-debugging daemon in the
1716 foreground. If background_daemon is true, close all open file descriptors that
1717 we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1718 do this for inetd_wait mode.
1720 This is protection against any called functions (in libraries, or in
1721 Perl, or whatever) that think they can write to stderr (or stdout). Before this
1722 was added, it was quite likely that an SMTP connection would use one of these
1723 file descriptors, in which case writing random stuff to it caused chaos.
1725 Then disconnect from the controlling terminal, Most modern Unixes seem to have
1726 setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1727 setsid() can be #defined as a no-op, or as something else. */
1729 if (f.background_daemon || f.inetd_wait_mode)
1731 log_close_all(); /* Just in case anything was logged earlier */
1732 search_tidyup(); /* Just in case any were used in reading the config. */
1733 (void)close(0); /* Get rid of stdin/stdout/stderr */
1736 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
1737 log_stderr = NULL; /* So no attempt to copy paniclog output */
1740 if (f.background_daemon)
1742 /* If the parent process of this one has pid == 1, we are re-initializing the
1743 daemon as the result of a SIGHUP. In this case, there is no need to do
1744 anything, because the controlling terminal has long gone. Otherwise, fork, in
1745 case current process is a process group leader (see 'man setsid' for an
1746 explanation) before calling setsid(). */
1750 pid_t pid = exim_fork(US"daemon");
1751 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1752 "fork() failed when starting daemon: %s", strerror(errno));
1753 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1754 (void)setsid(); /* release controlling terminal */
1758 /* We are now in the disconnected, daemon process (unless debugging). Set up
1759 the listening sockets if required. */
1761 daemon_notifier_socket();
1763 if (f.daemon_listen && !f.inetd_wait_mode)
1766 ip_address_item *ipa;
1768 /* For each IP address, create a socket, bind it to the appropriate port, and
1769 start listening. See comments above about IPv6 sockets that may or may not
1770 accept IPv4 calls when listening on all interfaces. We also have to cope with
1771 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1772 listening, provided a wildcard IPv4 socket for the same port follows. */
1774 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1777 ip_address_item * ipa2;
1780 if (Ustrchr(ipa->address, ':') != NULL)
1783 wildcard = ipa->address[1] == 0;
1788 wildcard = ipa->address[0] == 0;
1791 if ((listen_sockets[sk] = fd = ip_socket(SOCK_STREAM, af)) < 0)
1793 if (check_special_case(0, addresses, ipa, FALSE))
1795 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1796 "listening (%s): will use IPv4", strerror(errno));
1799 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1800 (af == AF_INET6)? '6' : '4', strerror(errno));
1803 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1804 available. Just log failure (can get protocol not available, just like
1805 socket creation can). */
1808 if (af == AF_INET6 && wildcard &&
1809 setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, CS (&on),
1811 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1812 "socket failed (%s): carrying on without it", strerror(errno));
1813 #endif /* IPV6_V6ONLY */
1815 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1816 is being handled. Without this, a connection will prevent reuse of the
1817 smtp port for listening. */
1819 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
1820 US (&on), sizeof(on)) < 0)
1821 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1822 "failed when starting daemon: %s", strerror(errno));
1824 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1825 disable this because it breaks some broken clients. */
1827 if (tcp_nodelay) setsockopt(fd, IPPROTO_TCP, TCP_NODELAY,
1828 US (&on), sizeof(on));
1830 /* Now bind the socket to the required port; if Exim is being restarted
1831 it may not always be possible to bind immediately, even with SO_REUSEADDR
1832 set, so try 10 times, waiting between each try. After 10 failures, we give
1833 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1834 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1835 address for the same port, ignore the error on the grounds that we must be
1836 in a system where the IPv6 socket accepts both kinds of call. This is
1837 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1838 listen() stage instead. */
1841 f.tcp_fastopen_ok = TRUE;
1846 if (ip_bind(fd, af, ipa->address, ipa->port) >= 0) break;
1847 if (check_special_case(errno, addresses, ipa, TRUE))
1849 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1850 "listen() success; EADDRINUSE ignored\n");
1854 msg = US strerror(errno);
1860 if (daemon_startup_retries <= 0)
1861 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1862 "socket bind() to port %d for address %s failed: %s: "
1863 "daemon abandoned", ipa->port, addr, msg);
1864 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
1865 "failed: %s: waiting %s before trying again (%d more %s)",
1866 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1867 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1868 daemon_startup_retries--;
1869 sleep(daemon_startup_sleep);
1874 debug_printf("listening on all interfaces (IPv%c) port %d\n",
1875 af == AF_INET6 ? '6' : '4', ipa->port);
1877 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
1879 /* Start listening on the bound socket, establishing the maximum backlog of
1880 connections that is allowed. On success, add to the set of sockets for select
1881 and continue to the next address. */
1883 #if defined(TCP_FASTOPEN) && !defined(__APPLE__)
1884 if ( f.tcp_fastopen_ok
1885 && setsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN,
1886 &smtp_connect_backlog, sizeof(smtp_connect_backlog)))
1888 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1889 f.tcp_fastopen_ok = FALSE;
1892 if (listen(fd, smtp_connect_backlog) >= 0)
1894 #if defined(TCP_FASTOPEN) && defined(__APPLE__)
1895 if ( f.tcp_fastopen_ok
1896 && setsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN, &on, sizeof(on)))
1898 DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno));
1899 f.tcp_fastopen_ok = FALSE;
1903 add_listener_socket(fd, &select_listen, &listen_fd_max);
1907 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1908 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1909 and there was a previous successful IPv6 wildcard listen on the same port,
1910 we want to ignore the error on the grounds that we must be in a system
1911 where the IPv6 socket accepts both kinds of call. */
1913 if (!check_special_case(errno, addresses, ipa, TRUE))
1914 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
1916 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
1919 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1920 "listen() success; EADDRINUSE ignored\n");
1923 /* Come here if there has been a problem with the socket which we
1924 are going to ignore. We remove the address from the chain, and back up the
1928 sk--; /* Back up the count */
1929 listen_socket_count--; /* Reduce the total */
1930 if (ipa == addresses) addresses = ipa->next; else
1932 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1933 ipa2->next = ipa->next;
1936 } /* End of bind/listen loop for each address */
1937 } /* End of setup for listening */
1940 /* If we are not listening, we want to write a pid file only if -oP was
1941 explicitly given. */
1943 else if (!override_pid_file_path)
1946 /* Write the pid to a known file for assistance in identification, if required.
1947 We do this before giving up root privilege, because on some systems it is
1948 necessary to be root in order to write into the pid file directory. There's
1949 nothing to stop multiple daemons running, as long as no more than one listens
1950 on a given TCP/IP port on the same interface(s). However, in these
1951 circumstances it gets far too complicated to mess with pid file names
1952 automatically. Consequently, Exim 4 writes a pid file only
1954 (a) When running in the test harness, or
1955 (b) When -bd is used and -oX is not used, or
1956 (c) When -oP is used to supply a path.
1958 The variable daemon_write_pid is used to control this. */
1960 if (f.running_in_test_harness || write_pid)
1962 const enum pid_op operation = (f.running_in_test_harness
1963 || real_uid == root_uid
1964 || (real_uid == exim_uid && !override_pid_file_path)) ? PID_WRITE : PID_CHECK;
1965 if (!operate_on_pid_file(operation, getpid()))
1966 DEBUG(D_any) debug_printf("%s pid file %s: %s\n", (operation == PID_WRITE) ? "write" : "check", pid_file_path, strerror(errno));
1969 /* Add ancillary sockets to the set for select */
1972 if (tls_watch_fd >= 0)
1973 add_listener_socket(tls_watch_fd, &select_listen, &listen_fd_max);
1975 if (daemon_notifier_fd >= 0)
1976 add_listener_socket(daemon_notifier_fd, &select_listen, &listen_fd_max);
1980 /* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1982 sighup_seen = FALSE;
1983 signal(SIGHUP, sighup_handler);
1985 /* Give up root privilege at this point (assuming that exim_uid and exim_gid
1986 are not root). The third argument controls the running of initgroups().
1987 Normally we do this, in order to set up the groups for the Exim user. However,
1988 if we are not root at this time - some odd installations run that way - we
1991 exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1993 /* Update the originator_xxx fields so that received messages as listed as
1994 coming from Exim, not whoever started the daemon. */
1996 originator_uid = exim_uid;
1997 originator_gid = exim_gid;
1998 originator_login = (pw = getpwuid(exim_uid))
1999 ? string_copy_perm(US pw->pw_name, FALSE) : US"exim";
2001 /* Get somewhere to keep the list of queue-runner pids if we are keeping track
2002 of them (and also if we are doing queue runs). */
2004 if (queue_interval > 0 && local_queue_run_max > 0)
2006 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t), FALSE);
2007 for (int i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
2010 /* Set up the handler for termination of child processes, and the one
2011 telling us to die. */
2013 sigchld_seen = FALSE;
2014 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
2016 sigterm_seen = FALSE;
2017 os_non_restarting_signal(SIGTERM, main_sigterm_handler);
2018 os_non_restarting_signal(SIGINT, main_sigterm_handler);
2020 /* If we are to run the queue periodically, pretend the alarm has just gone
2021 off. This will cause the first queue-runner to get kicked off straight away. */
2023 sigalrm_seen = (queue_interval > 0);
2025 /* Log the start up of a daemon - at least one of listening or queue running
2028 if (f.inetd_wait_mode)
2030 uschar *p = big_buffer;
2032 if (inetd_wait_timeout >= 0)
2033 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
2035 sprintf(CS p, "with no wait timeout");
2037 log_write(0, LOG_MAIN,
2038 "exim %s daemon started: pid=%d, launched with listening socket, %s",
2039 version_string, getpid(), big_buffer);
2040 set_process_info("daemon(%s): pre-listening socket", version_string);
2042 /* set up the timeout logic */
2043 sigalrm_seen = TRUE;
2046 else if (f.daemon_listen)
2049 int smtps_ports = 0;
2050 ip_address_item * ipa;
2052 uschar * qinfo = queue_interval > 0
2053 ? string_sprintf("-q%s%s",
2054 f.queue_2stage ? "q" : "", readconf_printtime(queue_interval))
2055 : US"no queue runs";
2057 /* Build a list of listening addresses in big_buffer, but limit it to 10
2058 items. The style is for backwards compatibility.
2060 It is now possible to have some ports listening for SMTPS (the old,
2061 deprecated protocol that starts TLS without using STARTTLS), and others
2062 listening for standard SMTP. Keep their listings separate. */
2064 for (int j = 0, i; j < 2; j++)
2066 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
2068 /* First time round, look for SMTP ports; second time round, look for
2069 SMTPS ports. Build IP+port strings. */
2071 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
2078 /* Now the information about the port (and sometimes interface) */
2080 if (ipa->address[0] == ':' && ipa->address[1] == 0)
2082 if (ipa->next && ipa->next->address[0] == 0 &&
2083 ipa->next->port == ipa->port)
2085 ipa->log = string_sprintf(" port %d (IPv6 and IPv4)", ipa->port);
2086 (ipa = ipa->next)->log = NULL;
2088 else if (ipa->v6_include_v4)
2089 ipa->log = string_sprintf(" port %d (IPv6 with IPv4)", ipa->port);
2091 ipa->log = string_sprintf(" port %d (IPv6)", ipa->port);
2093 else if (ipa->address[0] == 0) /* v4 wildcard */
2094 ipa->log = string_sprintf(" port %d (IPv4)", ipa->port);
2095 else /* check for previously-seen IP */
2097 ip_address_item * i2;
2098 for (i2 = addresses; i2 != ipa; i2 = i2->next)
2099 if ( host_is_tls_on_connect_port(i2->port) == (j > 0)
2100 && Ustrcmp(ipa->address, i2->address) == 0
2102 { /* found; append port to list */
2103 for (p = i2->log; *p; ) p++; /* end of existing string */
2104 if (*--p == '}') *p = '\0'; /* drop EOL */
2105 while (isdigit(*--p)) ; /* char before port */
2107 i2->log = *p == ':' /* no list yet? */
2108 ? string_sprintf("%.*s{%s,%d}",
2109 (int)(p - i2->log + 1), i2->log, p+1, ipa->port)
2110 : string_sprintf("%s,%d}", i2->log, ipa->port);
2114 if (i2 == ipa) /* first-time IP */
2115 ipa->log = string_sprintf(" [%s]:%d", ipa->address, ipa->port);
2122 for (int j = 0, i; j < 2; j++)
2124 /* First time round, look for SMTP ports; second time round, look for
2125 SMTPS ports. For the first one of each, insert leading text. */
2130 p += sprintf(CS p, "SMTP on");
2133 if (smtps_ports > 0)
2134 p += sprintf(CS p, "%sSMTPS on",
2135 smtp_ports == 0 ? "" : " and for ");
2137 /* Now the information about the port (and sometimes interface) */
2139 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
2140 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
2142 p += sprintf(CS p, "%s", ipa->log);
2145 p += sprintf(CS p, " ...");
2148 log_write(0, LOG_MAIN,
2149 "exim %s daemon started: pid=%d, %s, listening for %s",
2150 version_string, getpid(), qinfo, big_buffer);
2151 set_process_info("daemon(%s): %s, listening for %s",
2152 version_string, qinfo, big_buffer);
2157 uschar * s = *queue_name
2158 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
2159 : string_sprintf("-q%s", readconf_printtime(queue_interval));
2160 log_write(0, LOG_MAIN,
2161 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
2162 version_string, getpid(), s);
2163 set_process_info("daemon(%s): %s, not listening", version_string, s);
2166 /* Do any work it might be useful to amortize over our children
2167 (eg: compile regex) */
2170 smtp_deliver_init(); /* Used for callouts */
2172 #ifndef DISABLE_DKIM
2174 # ifdef MEASURE_TIMING
2176 gettimeofday(&t0, NULL);
2179 # ifdef MEASURE_TIMING
2180 report_time_since(&t0, US"dkim_exim_init (delta)");
2185 #ifdef WITH_CONTENT_SCAN
2195 /* Close the log so it can be renamed and moved. In the few cases below where
2196 this long-running process writes to the log (always exceptional conditions), it
2197 closes the log afterwards, for the same reason. */
2201 DEBUG(D_any) debug_print_ids(US"daemon running with");
2203 /* Any messages accepted via this route are going to be SMTP. */
2207 #ifdef MEASURE_TIMING
2208 report_time_since(×tamp_startup, US"daemon loop start"); /* testcase 0022 */
2211 /* Enter the never-ending loop... */
2216 struct sockaddr_in6 accepted;
2218 struct sockaddr_in accepted;
2225 daemon_die(); /* Does not return */
2227 /* This code is placed first in the loop, so that it gets obeyed at the
2228 start, before the first wait, for the queue-runner case, so that the first
2229 one can be started immediately.
2231 The other option is that we have an inetd wait timeout specified to -bw. */
2235 if (inetd_wait_timeout > 0)
2237 time_t resignal_interval = inetd_wait_timeout;
2239 if (last_connection_time == (time_t)0)
2242 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
2246 time_t now = time(NULL);
2247 if (now == (time_t)-1)
2249 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
2253 if ((now - last_connection_time) >= inetd_wait_timeout)
2256 debug_printf("inetd wait timeout %d expired, ending daemon\n",
2257 inetd_wait_timeout);
2258 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
2264 resignal_interval -= (now - last_connection_time);
2269 sigalrm_seen = FALSE;
2270 ALARM(resignal_interval);
2275 DEBUG(D_any) debug_printf("%s received\n",
2276 #ifndef DISABLE_QUEUE_RAMP
2277 *queuerun_msgid ? "qrun notification" :
2281 /* Do a full queue run in a child process, if required, unless we already
2282 have enough queue runners on the go. If we are not running as root, a
2283 re-exec is required. */
2285 if ( queue_interval > 0
2286 && (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
2288 if ((pid = exim_fork(US"queue-runner")) == 0)
2290 /* Disable debugging if it's required only for the daemon process. We
2291 leave the above message, because it ties up with the "child ended"
2292 debugging messages. */
2294 if (f.debug_daemon) debug_selector = 0;
2296 /* Close any open listening sockets in the child */
2298 close_daemon_sockets(daemon_notifier_fd,
2299 listen_sockets, listen_socket_count);
2301 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
2303 signal(SIGHUP, SIG_DFL);
2304 signal(SIGCHLD, SIG_DFL);
2305 signal(SIGTERM, SIG_DFL);
2306 signal(SIGINT, SIG_DFL);
2308 /* Re-exec if privilege has been given up, unless deliver_drop_
2309 privilege is set. Reset SIGALRM before exec(). */
2311 if (geteuid() != root_uid && !deliver_drop_privilege)
2318 signal(SIGALRM, SIG_DFL);
2322 #ifndef DISABLE_QUEUE_RAMP
2326 if (f.queue_run_first_delivery) *p++ = 'i';
2327 if (f.queue_run_force) *p++ = 'f';
2328 if (f.deliver_force_thaw) *p++ = 'f';
2329 if (f.queue_run_local) *p++ = 'l';
2331 extra[0] = *queue_name
2332 ? string_sprintf("%sG%s", opt, queue_name) : opt;
2334 #ifndef DISABLE_QUEUE_RAMP
2335 if (*queuerun_msgid)
2337 log_write(0, LOG_MAIN, "notify triggered queue run");
2338 extra[extracount++] = queuerun_msgid; /* Trigger only the */
2339 extra[extracount++] = queuerun_msgid; /* one message */
2343 /* If -R or -S were on the original command line, ensure they get
2346 if (deliver_selectstring)
2348 extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R";
2349 extra[extracount++] = deliver_selectstring;
2352 if (deliver_selectstring_sender)
2354 extra[extracount++] = f.deliver_selectstring_sender_regex
2356 extra[extracount++] = deliver_selectstring_sender;
2359 /* Overlay this process with a new execution. */
2361 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE, extracount,
2362 extra[0], extra[1], extra[2], extra[3], extra[4], extra[5], extra[6]);
2364 /* Control never returns here. */
2367 /* No need to re-exec; SIGALRM remains set to the default handler */
2369 #ifndef DISABLE_QUEUE_RAMP
2370 if (*queuerun_msgid)
2372 log_write(0, LOG_MAIN, "notify triggered queue run");
2373 f.queue_2stage = FALSE;
2374 queue_run(queuerun_msgid, queuerun_msgid, FALSE);
2378 queue_run(NULL, NULL, FALSE);
2379 exim_underbar_exit(EXIT_SUCCESS);
2384 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
2385 "process failed: %s", strerror(errno));
2390 for (int i = 0; i < local_queue_run_max; ++i)
2391 if (queue_pid_slots[i] <= 0)
2393 queue_pid_slots[i] = pid;
2397 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
2398 queue_run_count, queue_run_count == 1 ? "" : "es");
2402 /* Reset the alarm clock */
2404 sigalrm_seen = FALSE;
2405 #ifndef DISABLE_QUEUE_RAMP
2406 if (*queuerun_msgid)
2407 *queuerun_msgid = 0;
2410 ALARM(queue_interval);
2413 } /* sigalrm_seen */
2416 /* Sleep till a connection happens if listening, and handle the connection if
2417 that is why we woke up. The FreeBSD operating system requires the use of
2418 select() before accept() because the latter function is not interrupted by
2419 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
2420 OS do notice signals in accept() but it does no harm to have the select()
2421 in for all of them - and it won't then be a lurking problem for ports to
2422 new OS. In fact, the later addition of listening on specific interfaces only
2423 requires this way of working anyway. */
2425 if (f.daemon_listen)
2428 BOOL select_failed = FALSE;
2429 fd_set fds = select_listen;
2431 DEBUG(D_any) debug_printf("Listening...\n");
2433 /* In rare cases we may have had a SIGCHLD signal in the time between
2434 setting the handler (below) and getting back here. If so, pretend that the
2435 select() was interrupted so that we reap the child. This might still leave
2436 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
2437 only to do the reaping more quickly, it shouldn't result in anything other
2438 than a delay until something else causes a wake-up. */
2446 lcount = select(listen_fd_max, (SELECT_ARG2_TYPE *)&fds,
2451 select_failed = TRUE;
2455 /* Clean up any subprocesses that may have terminated. We need to do this
2456 here so that smtp_accept_max_per_host works when a connection to that host
2457 has completed, and we are about to accept a new one. When this code was
2458 later in the sequence, a new connection could be rejected, even though an
2459 old one had just finished. Preserve the errno from any select() failure for
2460 the use of the common select/accept error processing below. */
2463 int select_errno = errno;
2464 handle_ending_processes();
2467 /* Create or rotate any required keys; handle (delayed) filewatch event */
2470 errno = select_errno;
2473 /* Loop for all the sockets that are currently ready to go. If select
2474 actually failed, we have set the count to 1 and select_failed=TRUE, so as
2475 to use the common error code for select/accept below. */
2477 while (lcount-- > 0)
2479 int accept_socket = -1;
2483 #if !defined(DISABLE_TLS) && (defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT))
2484 if (tls_watch_fd >= 0 && FD_ISSET(tls_watch_fd, &fds))
2486 FD_CLR(tls_watch_fd, &fds);
2487 tls_watch_trigger_time = time(NULL); /* Set up delayed event */
2488 tls_watch_discard_event(tls_watch_fd);
2489 break; /* to top of daemon loop */
2492 if (daemon_notifier_fd >= 0 && FD_ISSET(daemon_notifier_fd, &fds))
2494 FD_CLR(daemon_notifier_fd, &fds);
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], &fds))
2501 len = sizeof(accepted);
2502 accept_socket = accept(listen_sockets[sk],
2503 (struct sockaddr *)&accepted, &len);
2504 FD_CLR(listen_sockets[sk], &fds);
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 */