TFO: Support compilation on systems which define TCP_FASTOPEN but not MSG_FASTOPEN
[exim.git] / src / src / daemon.c
CommitLineData
059ec3d9
PH
1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
80fea873 5/* Copyright (c) University of Cambridge 1995 - 2016 */
059ec3d9
PH
6/* See the file NOTICE for conditions of use and distribution. */
7
8/* Functions concerned with running Exim as a daemon */
9
10
11#include "exim.h"
12
13
14/* Structure for holding data for each SMTP connection */
15
16typedef struct smtp_slot {
17 pid_t pid; /* pid of the spawned reception process */
18 uschar *host_address; /* address of the client host */
19} smtp_slot;
20
21/* An empty slot for initializing (Standard C does not allow constructor
22expressions in assigments except as initializers in declarations). */
23
24static smtp_slot empty_smtp_slot = { 0, NULL };
25
26
27
28/*************************************************
29* Local static variables *
30*************************************************/
31
cd59ab18
PP
32static SIGNAL_BOOL sigchld_seen;
33static SIGNAL_BOOL sighup_seen;
059ec3d9
PH
34
35static int accept_retry_count = 0;
36static int accept_retry_errno;
37static BOOL accept_retry_select_failed;
38
39static int queue_run_count = 0;
bb6e88ff
PH
40static pid_t *queue_pid_slots = NULL;
41static smtp_slot *smtp_slots = NULL;
059ec3d9
PH
42
43static BOOL write_pid = TRUE;
44
45
46
47/*************************************************
48* SIGHUP Handler *
49*************************************************/
50
51/* All this handler does is to set a flag and re-enable the signal.
52
53Argument: the signal number
54Returns: nothing
55*/
56
57static void
58sighup_handler(int sig)
59{
60sig = sig; /* Keep picky compilers happy */
61sighup_seen = TRUE;
62signal(SIGHUP, sighup_handler);
63}
64
65
66
67/*************************************************
68* SIGCHLD handler for main daemon process *
69*************************************************/
70
71/* Don't re-enable the handler here, since we aren't doing the
72waiting here. If the signal is re-enabled, there will just be an
73infinite sequence of calls to this handler. The SIGCHLD signal is
74used just as a means of waking up the daemon so that it notices
75terminated subprocesses as soon as possible.
76
77Argument: the signal number
78Returns: nothing
79*/
80
81static void
82main_sigchld_handler(int sig)
83{
84sig = sig; /* Keep picky compilers happy */
7d468ab8 85os_non_restarting_signal(SIGCHLD, SIG_DFL);
059ec3d9 86sigchld_seen = TRUE;
059ec3d9
PH
87}
88
89
90
91
92/*************************************************
93* Unexpected errors in SMTP calls *
94*************************************************/
95
96/* This function just saves a bit of repetitious coding.
97
98Arguments:
99 log_msg Text of message to be logged
100 smtp_msg Text of SMTP error message
101 was_errno The failing errno
102
103Returns: nothing
104*/
105
106static void
107never_error(uschar *log_msg, uschar *smtp_msg, int was_errno)
108{
109uschar *emsg = (was_errno <= 0)? US"" :
110 string_sprintf(": %s", strerror(was_errno));
111log_write(0, LOG_MAIN|LOG_PANIC, "%s%s", log_msg, emsg);
112if (smtp_out != NULL) smtp_printf("421 %s\r\n", smtp_msg);
113}
114
115
116
117
118/*************************************************
119* Handle a connected SMTP call *
120*************************************************/
121
122/* This function is called when an SMTP connection has been accepted.
123If there are too many, give an error message and close down. Otherwise
124spin off a sub-process to handle the call. The list of listening sockets
125is required so that they can be closed in the sub-process. Take care not to
126leak store in this process - reset the stacking pool at the end.
127
128Arguments:
129 listen_sockets sockets which are listening for incoming calls
130 listen_socket_count count of listening sockets
131 accept_socket socket of the current accepted call
132 accepted socket information about the current call
133
134Returns: nothing
135*/
136
137static void
138handle_smtp_call(int *listen_sockets, int listen_socket_count,
139 int accept_socket, struct sockaddr *accepted)
140{
141pid_t pid;
142union sockaddr_46 interface_sockaddr;
36a3b041 143EXIM_SOCKLEN_T ifsize = sizeof(interface_sockaddr);
059ec3d9
PH
144int dup_accept_socket = -1;
145int max_for_this_host = 0;
146int wfsize = 0;
147int wfptr = 0;
6c6d6e48 148int save_log_selector = *log_selector;
059ec3d9
PH
149uschar *whofrom = NULL;
150
151void *reset_point = store_get(0);
152
153/* Make the address available in ASCII representation, and also fish out
154the remote port. */
155
156sender_host_address = host_ntoa(-1, accepted, NULL, &sender_host_port);
157DEBUG(D_any) debug_printf("Connection request from %s port %d\n",
158 sender_host_address, sender_host_port);
159
160/* Set up the output stream, check the socket has duplicated, and set up the
161input stream. These operations fail only the exceptional circumstances. Note
162that never_error() won't use smtp_out if it is NULL. */
163
f5d25c2b 164if (!(smtp_out = fdopen(accept_socket, "wb")))
059ec3d9
PH
165 {
166 never_error(US"daemon: fdopen() for smtp_out failed", US"", errno);
167 goto ERROR_RETURN;
168 }
169
f5d25c2b 170if ((dup_accept_socket = dup(accept_socket)) < 0)
059ec3d9
PH
171 {
172 never_error(US"daemon: couldn't dup socket descriptor",
173 US"Connection setup failed", errno);
174 goto ERROR_RETURN;
175 }
176
f5d25c2b 177if (!(smtp_in = fdopen(dup_accept_socket, "rb")))
059ec3d9
PH
178 {
179 never_error(US"daemon: fdopen() for smtp_in failed",
180 US"Connection setup failed", errno);
181 goto ERROR_RETURN;
182 }
183
520de300
PH
184/* Get the data for the local interface address. Panic for most errors, but
185"connection reset by peer" just means the connection went away. */
059ec3d9
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186
187if (getsockname(accept_socket, (struct sockaddr *)(&interface_sockaddr),
188 &ifsize) < 0)
189 {
520de300
PH
190 log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC),
191 "getsockname() failed: %s", strerror(errno));
059ec3d9
PH
192 smtp_printf("421 Local problem: getsockname() failed; please try again later\r\n");
193 goto ERROR_RETURN;
194 }
195
196interface_address = host_ntoa(-1, &interface_sockaddr, NULL, &interface_port);
197DEBUG(D_interface) debug_printf("interface address=%s port=%d\n",
198 interface_address, interface_port);
199
200/* Build a string identifying the remote host and, if requested, the port and
201the local interface data. This is for logging; at the end of this function the
202memory is reclaimed. */
203
204whofrom = string_append(whofrom, &wfsize, &wfptr, 3, "[", sender_host_address, "]");
205
6c6d6e48 206if (LOGGING(incoming_port))
059ec3d9
PH
207 whofrom = string_append(whofrom, &wfsize, &wfptr, 2, ":", string_sprintf("%d",
208 sender_host_port));
209
6c6d6e48 210if (LOGGING(incoming_interface))
059ec3d9
PH
211 whofrom = string_append(whofrom, &wfsize, &wfptr, 4, " I=[",
212 interface_address, "]:", string_sprintf("%d", interface_port));
213
214whofrom[wfptr] = 0; /* Terminate the newly-built string */
215
216/* Check maximum number of connections. We do not check for reserved
217connections or unacceptable hosts here. That is done in the subprocess because
218it might take some time. */
219
220if (smtp_accept_max > 0 && smtp_accept_count >= smtp_accept_max)
221 {
222 DEBUG(D_any) debug_printf("rejecting SMTP connection: count=%d max=%d\n",
223 smtp_accept_count, smtp_accept_max);
224 smtp_printf("421 Too many concurrent SMTP connections; "
225 "please try again later.\r\n");
226 log_write(L_connection_reject,
227 LOG_MAIN, "Connection from %s refused: too many connections",
228 whofrom);
229 goto ERROR_RETURN;
230 }
231
232/* If a load limit above which only reserved hosts are acceptable is defined,
233get the load average here, and if there are in fact no reserved hosts, do
234the test right away (saves a fork). If there are hosts, do the check in the
235subprocess because it might take time. */
236
237if (smtp_load_reserve >= 0)
238 {
8669f003 239 load_average = OS_GETLOADAVG();
059ec3d9
PH
240 if (smtp_reserve_hosts == NULL && load_average > smtp_load_reserve)
241 {
242 DEBUG(D_any) debug_printf("rejecting SMTP connection: load average = %.2f\n",
243 (double)load_average/1000.0);
244 smtp_printf("421 Too much load; please try again later.\r\n");
245 log_write(L_connection_reject,
246 LOG_MAIN, "Connection from %s refused: load average = %.2f",
247 whofrom, (double)load_average/1000.0);
248 goto ERROR_RETURN;
249 }
250 }
251
252/* Check that one specific host (strictly, IP address) is not hogging
253resources. This is done here to prevent a denial of service attack by someone
254forcing you to fork lots of times before denying service. The value of
255smtp_accept_max_per_host is a string which is expanded. This makes it possible
256to provide host-specific limits according to $sender_host address, but because
257this is in the daemon mainline, only fast expansions (such as inline address
258checks) should be used. The documentation is full of warnings. */
259
260if (smtp_accept_max_per_host != NULL)
261 {
262 uschar *expanded = expand_string(smtp_accept_max_per_host);
263 if (expanded == NULL)
264 {
265 if (!expand_string_forcedfail)
266 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
267 "failed for %s: %s", whofrom, expand_string_message);
268 }
269 /* For speed, interpret a decimal number inline here */
270 else
271 {
272 uschar *s = expanded;
273 while (isdigit(*s))
274 max_for_this_host = max_for_this_host * 10 + *s++ - '0';
275 if (*s != 0)
276 log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host "
277 "for %s contains non-digit: %s", whofrom, expanded);
278 }
279 }
280
281/* If we have fewer connections than max_for_this_host, we can skip the tedious
282per host_address checks. Note that at this stage smtp_accept_count contains the
283count of *other* connections, not including this one. */
284
285if ((max_for_this_host > 0) &&
286 (smtp_accept_count >= max_for_this_host))
287 {
288 int i;
289 int host_accept_count = 0;
290 int other_host_count = 0; /* keep a count of non matches to optimise */
291
292 for (i = 0; i < smtp_accept_max; ++i)
059ec3d9
PH
293 if (smtp_slots[i].host_address != NULL)
294 {
295 if (Ustrcmp(sender_host_address, smtp_slots[i].host_address) == 0)
296 host_accept_count++;
297 else
298 other_host_count++;
299
300 /* Testing all these strings is expensive - see if we can drop out
301 early, either by hitting the target, or finding there are not enough
302 connections left to make the target. */
303
304 if ((host_accept_count >= max_for_this_host) ||
305 ((smtp_accept_count - other_host_count) < max_for_this_host))
306 break;
307 }
059ec3d9
PH
308
309 if (host_accept_count >= max_for_this_host)
310 {
311 DEBUG(D_any) debug_printf("rejecting SMTP connection: too many from this "
312 "IP address: count=%d max=%d\n",
313 host_accept_count, max_for_this_host);
314 smtp_printf("421 Too many concurrent SMTP connections "
315 "from this IP address; please try again later.\r\n");
316 log_write(L_connection_reject,
317 LOG_MAIN, "Connection from %s refused: too many connections "
318 "from that IP address", whofrom);
319 goto ERROR_RETURN;
320 }
321 }
322
323/* OK, the connection count checks have been passed. Before we can fork the
324accepting process, we must first log the connection if requested. This logging
325used to happen in the subprocess, but doing that means that the value of
326smtp_accept_count can be out of step by the time it is logged. So we have to do
327the logging here and accept the performance cost. Note that smtp_accept_count
328hasn't yet been incremented to take account of this connection.
329
330In order to minimize the cost (because this is going to happen for every
331connection), do a preliminary selector test here. This saves ploughing through
332the generalized logging code each time when the selector is false. If the
333selector is set, check whether the host is on the list for logging. If not,
334arrange to unset the selector in the subprocess. */
335
6c6d6e48 336if (LOGGING(smtp_connection))
059ec3d9
PH
337 {
338 uschar *list = hosts_connection_nolog;
ce325893 339 memset(sender_host_cache, 0, sizeof(sender_host_cache));
059ec3d9 340 if (list != NULL && verify_check_host(&list) == OK)
6c6d6e48 341 save_log_selector &= ~L_smtp_connection;
059ec3d9
PH
342 else
343 log_write(L_smtp_connection, LOG_MAIN, "SMTP connection from %s "
344 "(TCP/IP connection count = %d)", whofrom, smtp_accept_count + 1);
345 }
346
347/* Now we can fork the accepting process; do a lookup tidy, just in case any
348expansion above did a lookup. */
349
350search_tidyup();
351pid = fork();
352
353/* Handle the child process */
354
355if (pid == 0)
356 {
357 int i;
358 int queue_only_reason = 0;
359 int old_pool = store_pool;
8e669ac1 360 int save_debug_selector = debug_selector;
059ec3d9 361 BOOL local_queue_only;
8669f003 362 BOOL session_local_queue_only;
059ec3d9
PH
363 #ifdef SA_NOCLDWAIT
364 struct sigaction act;
365 #endif
366
b01dd148
PH
367 smtp_accept_count++; /* So that it includes this process */
368
059ec3d9
PH
369 /* May have been modified for the subprocess */
370
6c6d6e48 371 *log_selector = save_log_selector;
059ec3d9
PH
372
373 /* Get the local interface address into permanent store */
374
375 store_pool = POOL_PERM;
376 interface_address = string_copy(interface_address);
377 store_pool = old_pool;
378
379 /* Check for a tls-on-connect port */
380
817d9f57 381 if (host_is_tls_on_connect_port(interface_port)) tls_in.on_connect = TRUE;
059ec3d9
PH
382
383 /* Expand smtp_active_hostname if required. We do not do this any earlier,
384 because it may depend on the local interface address (indeed, that is most
385 likely what it depends on.) */
386
387 smtp_active_hostname = primary_hostname;
388 if (raw_active_hostname != NULL)
389 {
390 uschar *nah = expand_string(raw_active_hostname);
391 if (nah == NULL)
392 {
393 if (!expand_string_forcedfail)
394 {
395 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand \"%s\" "
396 "(smtp_active_hostname): %s", raw_active_hostname,
397 expand_string_message);
398 smtp_printf("421 Local configuration error; "
399 "please try again later.\r\n");
400 mac_smtp_fflush();
401 search_tidyup();
402 _exit(EXIT_FAILURE);
403 }
404 }
405 else if (nah[0] != 0) smtp_active_hostname = nah;
406 }
407
408 /* Initialize the queueing flags */
409
410 queue_check_only();
8669f003 411 session_local_queue_only = queue_only;
059ec3d9
PH
412
413 /* Close the listening sockets, and set the SIGCHLD handler to SIG_IGN.
414 We also attempt to set things up so that children are automatically reaped,
415 but just in case this isn't available, there's a paranoid waitpid() in the
416 loop too (except for systems where we are sure it isn't needed). See the more
417 extensive comment before the reception loop in exim.c for a fuller
418 explanation of this logic. */
419
f1e894f3 420 for (i = 0; i < listen_socket_count; i++) (void)close(listen_sockets[i]);
059ec3d9 421
fa32850b
DW
422 /* Set FD_CLOEXEC on the SMTP socket. We don't want any rogue child processes
423 to be able to communicate with them, under any circumstances. */
424 (void)fcntl(accept_socket, F_SETFD,
425 fcntl(accept_socket, F_GETFD) | FD_CLOEXEC);
426 (void)fcntl(dup_accept_socket, F_SETFD,
427 fcntl(dup_accept_socket, F_GETFD) | FD_CLOEXEC);
428
059ec3d9
PH
429 #ifdef SA_NOCLDWAIT
430 act.sa_handler = SIG_IGN;
431 sigemptyset(&(act.sa_mask));
432 act.sa_flags = SA_NOCLDWAIT;
433 sigaction(SIGCHLD, &act, NULL);
434 #else
435 signal(SIGCHLD, SIG_IGN);
436 #endif
437
438 /* Attempt to get an id from the sending machine via the RFC 1413
439 protocol. We do this in the sub-process in order not to hold up the
440 main process if there is any delay. Then set up the fullhost information
8e669ac1
PH
441 in case there is no HELO/EHLO.
442
443 If debugging is enabled only for the daemon, we must turn if off while
444 finding the id, but turn it on again afterwards so that information about the
3d235903 445 incoming connection is output. */
8e669ac1 446
3d235903 447 if (debug_daemon) debug_selector = 0;
059ec3d9
PH
448 verify_get_ident(IDENT_PORT);
449 host_build_sender_fullhost();
8e669ac1 450 debug_selector = save_debug_selector;
059ec3d9
PH
451
452 DEBUG(D_any)
453 debug_printf("Process %d is handling incoming connection from %s\n",
454 (int)getpid(), sender_fullhost);
455
3d235903
PH
456 /* Now disable debugging permanently if it's required only for the daemon
457 process. */
458
459 if (debug_daemon) debug_selector = 0;
460
059ec3d9 461 /* If there are too many child processes for immediate delivery,
8669f003 462 set the session_local_queue_only flag, which is initialized from the
059ec3d9 463 configured value and may therefore already be TRUE. Leave logging
8669f003
PH
464 till later so it will have a message id attached. Note that there is no
465 possibility of re-calculating this per-message, because the value of
466 smtp_accept_count does not change in this subprocess. */
059ec3d9 467
b01dd148 468 if (smtp_accept_queue > 0 && smtp_accept_count > smtp_accept_queue)
059ec3d9 469 {
8669f003 470 session_local_queue_only = TRUE;
059ec3d9
PH
471 queue_only_reason = 1;
472 }
473
474 /* Handle the start of the SMTP session, then loop, accepting incoming
475 messages from the SMTP connection. The end will come at the QUIT command,
476 when smtp_setup_msg() returns 0. A break in the connection causes the
24796b8d
PH
477 process to die (see accept.c).
478
479 NOTE: We do *not* call smtp_log_no_mail() if smtp_start_session() fails,
480 because a log line has already been written for all its failure exists
481 (usually "connection refused: <reason>") and writing another one is
482 unnecessary clutter. */
059ec3d9
PH
483
484 if (!smtp_start_session())
485 {
486 mac_smtp_fflush();
487 search_tidyup();
488 _exit(EXIT_SUCCESS);
489 }
490
491 for (;;)
492 {
493 int rc;
494 message_id[0] = 0; /* Clear out any previous message_id */
495 reset_point = store_get(0); /* Save current store high water point */
496
497 DEBUG(D_any)
498 debug_printf("Process %d is ready for new message\n", (int)getpid());
499
500 /* Smtp_setup_msg() returns 0 on QUIT or if the call is from an
501 unacceptable host or if an ACL "drop" command was triggered, -1 on
502 connection lost, and +1 on validly reaching DATA. Receive_msg() almost
503 always returns TRUE when smtp_input is true; just retry if no message was
504 accepted (can happen for invalid message parameters). However, it can yield
505 FALSE if the connection was forcibly dropped by the DATA ACL. */
506
507 if ((rc = smtp_setup_msg()) > 0)
508 {
509 BOOL ok = receive_msg(FALSE);
510 search_tidyup(); /* Close cached databases */
511 if (!ok) /* Connection was dropped */
512 {
513 mac_smtp_fflush();
b4ed4da0 514 smtp_log_no_mail(); /* Log no mail if configured */
059ec3d9
PH
515 _exit(EXIT_SUCCESS);
516 }
517 if (message_id[0] == 0) continue; /* No message was accepted */
518 }
519 else
520 {
60d10ce7
JH
521 int i;
522 uschar * buf[128];
059ec3d9 523 mac_smtp_fflush();
60d10ce7
JH
524 /* drain socket, for clean TCP FINs */
525 for(i = 16; read(fileno(smtp_in), buf, sizeof(buf)) > 0 && i > 0; ) i--;
059ec3d9 526 search_tidyup();
b4ed4da0 527 smtp_log_no_mail(); /* Log no mail if configured */
60d10ce7
JH
528
529 /*XXX should we pause briefly, hoping that the client will be the
530 active TCP closer hence get the TCP_WAIT endpoint? */
531 DEBUG(D_receive) debug_printf("SMTP>>(close on process exit)\n");
f5d25c2b 532 _exit(rc ? EXIT_FAILURE : EXIT_SUCCESS);
059ec3d9
PH
533 }
534
535 /* Show the recipients when debugging */
536
537 DEBUG(D_receive)
538 {
539 int i;
540 if (sender_address != NULL)
541 debug_printf("Sender: %s\n", sender_address);
542 if (recipients_list != NULL)
543 {
544 debug_printf("Recipients:\n");
545 for (i = 0; i < recipients_count; i++)
546 debug_printf(" %s\n", recipients_list[i].address);
547 }
548 }
549
550 /* A message has been accepted. Clean up any previous delivery processes
551 that have completed and are defunct, on systems where they don't go away
552 by themselves (see comments when setting SIG_IGN above). On such systems
553 (if any) these delivery processes hang around after termination until
554 the next message is received. */
555
556 #ifndef SIG_IGN_WORKS
557 while (waitpid(-1, NULL, WNOHANG) > 0);
558 #endif
559
560 /* Reclaim up the store used in accepting this message */
561
562 store_reset(reset_point);
563
564 /* If queue_only is set or if there are too many incoming connections in
8669f003
PH
565 existence, session_local_queue_only will be TRUE. If it is not, check
566 whether we have received too many messages in this session for immediate
567 delivery. */
568
569 if (!session_local_queue_only &&
570 smtp_accept_queue_per_connection > 0 &&
571 receive_messagecount > smtp_accept_queue_per_connection)
059ec3d9 572 {
8669f003
PH
573 session_local_queue_only = TRUE;
574 queue_only_reason = 2;
575 }
576
577 /* Initialize local_queue_only from session_local_queue_only. If it is not
578 true, and queue_only_load is set, check that the load average is below it.
579 If local_queue_only is set by this means, we also set if for the session if
580 queue_only_load_latch is true (the default). This means that, once set,
581 local_queue_only remains set for any subsequent messages on the same SMTP
582 connection. This is a deliberate choice; even though the load average may
583 fall, it doesn't seem right to deliver later messages on the same call when
584 not delivering earlier ones. However, the are special circumstances such as
585 very long-lived connections from scanning appliances where this is not the
586 best strategy. In such cases, queue_only_load_latch should be set false. */
587
f5d25c2b
JH
588 if ( !(local_queue_only = session_local_queue_only)
589 && queue_only_load >= 0
590 && (local_queue_only = (load_average = OS_GETLOADAVG()) > queue_only_load)
591 )
8669f003 592 {
f5d25c2b
JH
593 queue_only_reason = 3;
594 if (queue_only_load_latch) session_local_queue_only = TRUE;
059ec3d9
PH
595 }
596
597 /* Log the queueing here, when it will get a message id attached, but
598 not if queue_only is set (case 0). */
599
600 if (local_queue_only) switch(queue_only_reason)
601 {
f5d25c2b 602 case 1: log_write(L_delay_delivery,
059ec3d9
PH
603 LOG_MAIN, "no immediate delivery: too many connections "
604 "(%d, max %d)", smtp_accept_count, smtp_accept_queue);
f5d25c2b 605 break;
059ec3d9 606
f5d25c2b 607 case 2: log_write(L_delay_delivery,
059ec3d9
PH
608 LOG_MAIN, "no immediate delivery: more than %d messages "
609 "received in one connection", smtp_accept_queue_per_connection);
f5d25c2b 610 break;
059ec3d9 611
f5d25c2b 612 case 3: log_write(L_delay_delivery,
059ec3d9
PH
613 LOG_MAIN, "no immediate delivery: load average %.2f",
614 (double)load_average/1000.0);
f5d25c2b 615 break;
059ec3d9
PH
616 }
617
618 /* If a delivery attempt is required, spin off a new process to handle it.
619 If we are not root, we have to re-exec exim unless deliveries are being
620 done unprivileged. */
621
622 else if (!queue_only_policy && !deliver_freeze)
623 {
624 pid_t dpid;
625
626 /* Before forking, ensure that the C output buffer is flushed. Otherwise
627 anything that it in it will get duplicated, leading to duplicate copies
628 of the pending output. */
629
630 mac_smtp_fflush();
631
632 if ((dpid = fork()) == 0)
633 {
f1e894f3
PH
634 (void)fclose(smtp_in);
635 (void)fclose(smtp_out);
059ec3d9
PH
636
637 /* Don't ever molest the parent's SSL connection, but do clean up
638 the data structures if necessary. */
639
640 #ifdef SUPPORT_TLS
a400eccf 641 tls_close(TRUE, FALSE);
059ec3d9
PH
642 #endif
643
644 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
645
646 signal(SIGHUP, SIG_DFL);
647 signal(SIGCHLD, SIG_DFL);
648
649 if (geteuid() != root_uid && !deliver_drop_privilege)
650 {
651 signal(SIGALRM, SIG_DFL);
e37f8a84
JH
652 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, FALSE,
653 2, US"-Mc", message_id);
059ec3d9
PH
654 /* Control does not return here. */
655 }
656
657 /* No need to re-exec; SIGALRM remains set to the default handler */
658
659 (void)deliver_message(message_id, FALSE, FALSE);
660 search_tidyup();
661 _exit(EXIT_SUCCESS);
662 }
663
664 if (dpid > 0)
665 {
666 DEBUG(D_any) debug_printf("forked delivery process %d\n", (int)dpid);
667 }
668 else
059ec3d9
PH
669 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: delivery process fork "
670 "failed: %s", strerror(errno));
059ec3d9
PH
671 }
672 }
673 }
674
675
676/* Carrying on in the parent daemon process... Can't do much if the fork
677failed. Otherwise, keep count of the number of accepting processes and
678remember the pid for ticking off when the child completes. */
679
680if (pid < 0)
059ec3d9 681 never_error(US"daemon: accept process fork failed", US"Fork failed", errno);
059ec3d9
PH
682else
683 {
684 int i;
685 for (i = 0; i < smtp_accept_max; ++i)
059ec3d9
PH
686 if (smtp_slots[i].pid <= 0)
687 {
688 smtp_slots[i].pid = pid;
689 if (smtp_accept_max_per_host != NULL)
690 smtp_slots[i].host_address = string_copy_malloc(sender_host_address);
691 smtp_accept_count++;
692 break;
693 }
059ec3d9
PH
694 DEBUG(D_any) debug_printf("%d SMTP accept process%s running\n",
695 smtp_accept_count, (smtp_accept_count == 1)? "" : "es");
696 }
697
698/* Get here via goto in error cases */
699
700ERROR_RETURN:
701
702/* Close the streams associated with the socket which will also close the
703socket fds in this process. We can't do anything if fclose() fails, but
704logging brings it to someone's attention. However, "connection reset by peer"
1f872c80
PH
705isn't really a problem, so skip that one. On Solaris, a dropped connection can
706manifest itself as a broken pipe, so drop that one too. If the streams don't
707exist, something went wrong while setting things up. Make sure the socket
708descriptors are closed, in order to drop the connection. */
059ec3d9 709
f5d25c2b 710if (smtp_out)
059ec3d9 711 {
1f872c80 712 if (fclose(smtp_out) != 0 && errno != ECONNRESET && errno != EPIPE)
059ec3d9
PH
713 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_out) failed: %s",
714 strerror(errno));
715 smtp_out = NULL;
716 }
f1e894f3 717else (void)close(accept_socket);
059ec3d9 718
f5d25c2b 719if (smtp_in)
059ec3d9 720 {
1f872c80 721 if (fclose(smtp_in) != 0 && errno != ECONNRESET && errno != EPIPE)
059ec3d9
PH
722 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_in) failed: %s",
723 strerror(errno));
724 smtp_in = NULL;
725 }
f1e894f3 726else (void)close(dup_accept_socket);
059ec3d9
PH
727
728/* Release any store used in this process, including the store used for holding
729the incoming host address and an expanded active_hostname. */
730
c8899c20 731log_close_all();
059ec3d9
PH
732store_reset(reset_point);
733sender_host_address = NULL;
734}
735
736
737
738
739/*************************************************
740* Check wildcard listen special cases *
741*************************************************/
742
743/* This function is used when binding and listening on lists of addresses and
744ports. It tests for special cases of wildcard listening, when IPv4 and IPv6
745sockets may interact in different ways in different operating systems. It is
746passed an error number, the list of listening addresses, and the current
747address. Two checks are available: for a previous wildcard IPv6 address, or for
748a following wildcard IPv4 address, in both cases on the same port.
749
750In practice, pairs of wildcard addresses should be adjacent in the address list
751because they are sorted that way below.
752
753Arguments:
754 eno the error number
755 addresses the list of addresses
756 ipa the current IP address
757 back if TRUE, check for previous wildcard IPv6 address
758 if FALSE, check for a following wildcard IPv4 address
759
760Returns: TRUE or FALSE
761*/
762
763static BOOL
764check_special_case(int eno, ip_address_item *addresses, ip_address_item *ipa,
765 BOOL back)
766{
767ip_address_item *ipa2;
768
769/* For the "back" case, if the failure was "address in use" for a wildcard IPv4
770address, seek a previous IPv6 wildcard address on the same port. As it is
771previous, it must have been successfully bound and be listening. Flag it as a
772"6 including 4" listener. */
773
774if (back)
775 {
776 if (eno != EADDRINUSE || ipa->address[0] != 0) return FALSE;
777 for (ipa2 = addresses; ipa2 != ipa; ipa2 = ipa2->next)
778 {
779 if (ipa2->address[1] == 0 && ipa2->port == ipa->port)
780 {
781 ipa2->v6_include_v4 = TRUE;
782 return TRUE;
783 }
784 }
785 }
786
787/* For the "forward" case, if the current address is a wildcard IPv6 address,
788we seek a following wildcard IPv4 address on the same port. */
789
790else
791 {
792 if (ipa->address[0] != ':' || ipa->address[1] != 0) return FALSE;
793 for (ipa2 = ipa->next; ipa2 != NULL; ipa2 = ipa2->next)
794 if (ipa2->address[0] == 0 && ipa->port == ipa2->port) return TRUE;
795 }
796
797return FALSE;
798}
799
800
801
802
bb6e88ff
PH
803/*************************************************
804* Handle terminating subprocesses *
805*************************************************/
806
807/* Handle the termination of child processes. Theoretically, this need be done
808only when sigchld_seen is TRUE, but rumour has it that some systems lose
809SIGCHLD signals at busy times, so to be on the safe side, this function is
810called each time round. It shouldn't be too expensive.
811
812Arguments: none
813Returns: nothing
814*/
815
816static void
817handle_ending_processes(void)
818{
819int status;
820pid_t pid;
821
822while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
823 {
824 int i;
7be682ca
PP
825 DEBUG(D_any)
826 {
827 debug_printf("child %d ended: status=0x%x\n", (int)pid, status);
828#ifdef WCOREDUMP
829 if (WIFEXITED(status))
830 debug_printf(" normal exit, %d\n", WEXITSTATUS(status));
831 else if (WIFSIGNALED(status))
832 debug_printf(" signal exit, signal %d%s\n", WTERMSIG(status),
833 WCOREDUMP(status) ? " (core dumped)" : "");
834#endif
835 }
bb6e88ff 836
8e669ac1 837 /* If it's a listening daemon for which we are keeping track of individual
bb6e88ff
PH
838 subprocesses, deal with an accepting process that has terminated. */
839
840 if (smtp_slots != NULL)
841 {
842 for (i = 0; i < smtp_accept_max; i++)
843 {
844 if (smtp_slots[i].pid == pid)
845 {
846 if (smtp_slots[i].host_address != NULL)
847 store_free(smtp_slots[i].host_address);
848 smtp_slots[i] = empty_smtp_slot;
849 if (--smtp_accept_count < 0) smtp_accept_count = 0;
850 DEBUG(D_any) debug_printf("%d SMTP accept process%s now running\n",
851 smtp_accept_count, (smtp_accept_count == 1)? "" : "es");
852 break;
853 }
854 }
855 if (i < smtp_accept_max) continue; /* Found an accepting process */
856 }
857
858 /* If it wasn't an accepting process, see if it was a queue-runner
859 process that we are tracking. */
860
0cd5fd23 861 if (queue_pid_slots)
bb6e88ff 862 {
4dc2379a 863 int max = atoi(CS expand_string(queue_run_max));
0cd5fd23 864 for (i = 0; i < max; i++)
bb6e88ff
PH
865 if (queue_pid_slots[i] == pid)
866 {
867 queue_pid_slots[i] = 0;
868 if (--queue_run_count < 0) queue_run_count = 0;
869 DEBUG(D_any) debug_printf("%d queue-runner process%s now running\n",
870 queue_run_count, (queue_run_count == 1)? "" : "es");
871 break;
872 }
bb6e88ff
PH
873 }
874 }
875}
876
059ec3d9
PH
877
878
879/*************************************************
880* Exim Daemon Mainline *
881*************************************************/
882
883/* The daemon can do two jobs, either of which is optional:
884
885(1) Listens for incoming SMTP calls and spawns off a sub-process to handle
886each one. This is requested by the -bd option, with -oX specifying the SMTP
887port on which to listen (for testing).
888
889(2) Spawns a queue-running process every so often. This is controlled by the
890-q option with a an interval time. (If no time is given, a single queue run
891is done from the main function, and control doesn't get here.)
892
893Root privilege is required in order to attach to port 25. Some systems require
894it when calling socket() rather than bind(). To cope with all cases, we run as
895root for both socket() and bind(). Some systems also require root in order to
896write to the pid file directory. This function must therefore be called as root
897if it is to work properly in all circumstances. Once the socket is bound and
898the pid file written, root privilege is given up if there is an exim uid.
899
900There are no arguments to this function, and it never returns. */
901
902void
903daemon_go(void)
904{
ebeaf996 905struct passwd *pw;
059ec3d9
PH
906int *listen_sockets = NULL;
907int listen_socket_count = 0;
908ip_address_item *addresses = NULL;
9ee44efb 909time_t last_connection_time = (time_t)0;
4dc2379a 910int local_queue_run_max = atoi(CS expand_string(queue_run_max));
059ec3d9
PH
911
912/* If any debugging options are set, turn on the D_pid bit so that all
913debugging lines get the pid added. */
914
915DEBUG(D_any|D_v) debug_selector |= D_pid;
916
9ee44efb
PP
917if (inetd_wait_mode)
918 {
9ee44efb 919 listen_socket_count = 1;
96f5fe4c 920 listen_sockets = store_get(sizeof(int));
9ee44efb
PP
921 (void) close(3);
922 if (dup2(0, 3) == -1)
9ee44efb
PP
923 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
924 "failed to dup inetd socket safely away: %s", strerror(errno));
d4ff61d1 925
9ee44efb
PP
926 listen_sockets[0] = 3;
927 (void) close(0);
928 (void) close(1);
929 (void) close(2);
930 exim_nullstd();
931
932 if (debug_file == stderr)
933 {
934 /* need a call to log_write before call to open debug_file, so that
935 log.c:file_path has been initialised. This is unfortunate. */
936 log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting");
937
938 fclose(debug_file);
939 debug_file = NULL;
940 exim_nullstd(); /* re-open fd2 after we just closed it again */
941 debug_logging_activate(US"-wait", NULL);
942 }
943
944 DEBUG(D_any) debug_printf("running in inetd wait mode\n");
945
946 /* As per below, when creating sockets ourselves, we handle tcp_nodelay for
947 our own buffering; we assume though that inetd set the socket REUSEADDR. */
948
d4ff61d1
JH
949 if (tcp_nodelay)
950 if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
951 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s",
952 strerror(errno));
9ee44efb
PP
953 }
954
955
956if (inetd_wait_mode || daemon_listen)
957 {
958 /* If any option requiring a load average to be available during the
959 reception of a message is set, call os_getloadavg() while we are root
960 for those OS for which this is necessary the first time it is called (in
961 order to perform an "open" on the kernel memory file). */
962
963 #ifdef LOAD_AVG_NEEDS_ROOT
964 if (queue_only_load >= 0 || smtp_load_reserve >= 0 ||
965 (deliver_queue_load_max >= 0 && deliver_drop_privilege))
966 (void)os_getloadavg();
967 #endif
968 }
969
059ec3d9
PH
970
971/* Do the preparation for setting up a listener on one or more interfaces, and
972possible on various ports. This is controlled by the combination of
973local_interfaces (which can set IP addresses and ports) and daemon_smtp_port
974(which is a list of default ports to use for those items in local_interfaces
975that do not specify a port). The -oX command line option can be used to
976override one or both of these options.
977
978If local_interfaces is not set, the default is to listen on all interfaces.
979When it is set, it can include "all IPvx interfaces" as an item. This is useful
980when different ports are in use.
981
982It turns out that listening on all interfaces is messy in an IPv6 world,
983because several different implementation approaches have been taken. This code
984is now supposed to work with all of them. The point of difference is whether an
985IPv6 socket that is listening on all interfaces will receive incoming IPv4
986calls or not. We also have to cope with the case when IPv6 libraries exist, but
987there is no IPv6 support in the kernel.
988
989. On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped
990 addresses. However, if an IPv4 socket is also listening on all interfaces,
991 calls are directed to the appropriate socket.
992
993. On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and
994 give them as mapped addresses, but an attempt also to listen on an IPv4
995 socket on all interfaces causes an error.
996
997. On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up
998 two sockets if you want to accept both kinds of call.
999
1000. FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which
1001 can be turned off, to make it behave like the versions of Linux described
1002 above.
1003
1004. I heard a report that the USAGI IPv6 stack for Linux has implemented
1005 IPV6_V6ONLY.
1006
1007So, what we do when IPv6 is supported is as follows:
1008
1009 (1) After it is set up, the list of interfaces is scanned for wildcard
1010 addresses. If an IPv6 and an IPv4 wildcard are both found for the same
1011 port, the list is re-arranged so that they are together, with the IPv6
1012 wildcard first.
1013
1014 (2) If the creation of a wildcard IPv6 socket fails, we just log the error and
1015 carry on if an IPv4 wildcard socket for the same port follows later in the
1016 list. This allows Exim to carry on in the case when the kernel has no IPv6
1017 support.
1018
1019 (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that
1020 option is defined. However, if setting fails, carry on regardless (but log
1021 the incident).
1022
1023 (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious
1024 error.
1025
1026 (5) If binding or listening on an IPv4 wildcard socket fails with the error
1027 EADDRINUSE, and a previous interface was an IPv6 wildcard for the same
1028 port (which must have succeeded or we wouldn't have got this far), we
1029 assume we are in the situation where just a single socket is permitted,
1030 and ignore the error.
1031
1032Phew!
1033
1034The preparation code decodes options and sets up the relevant data. We do this
1035first, so that we can return non-zero if there are any syntax errors, and also
1036write to stderr. */
1037
602e0254 1038if (daemon_listen && !inetd_wait_mode)
059ec3d9
PH
1039 {
1040 int *default_smtp_port;
1041 int sep;
1042 int pct = 0;
1043 uschar *s;
55414b25 1044 const uschar * list;
059ec3d9
PH
1045 uschar *local_iface_source = US"local_interfaces";
1046 ip_address_item *ipa;
1047 ip_address_item **pipa;
1048
059ec3d9
PH
1049 /* If -oX was used, disable the writing of a pid file unless -oP was
1050 explicitly used to force it. Then scan the string given to -oX. Any items
1051 that contain neither a dot nor a colon are used to override daemon_smtp_port.
1052 Any other items are used to override local_interfaces. */
1053
1054 if (override_local_interfaces != NULL)
1055 {
1056 uschar *new_smtp_port = NULL;
1057 uschar *new_local_interfaces = NULL;
1058 int portsize = 0;
1059 int portptr = 0;
1060 int ifacesize = 0;
1061 int ifaceptr = 0;
1062
1063 if (override_pid_file_path == NULL) write_pid = FALSE;
1064
1065 list = override_local_interfaces;
1066 sep = 0;
55414b25 1067 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
059ec3d9
PH
1068 {
1069 uschar joinstr[4];
1070 uschar **ptr;
1071 int *sizeptr;
1072 int *ptrptr;
1073
1074 if (Ustrpbrk(s, ".:") == NULL)
1075 {
1076 ptr = &new_smtp_port;
1077 sizeptr = &portsize;
1078 ptrptr = &portptr;
1079 }
1080 else
1081 {
1082 ptr = &new_local_interfaces;
1083 sizeptr = &ifacesize;
1084 ptrptr = &ifaceptr;
1085 }
1086
1087 if (*ptr == NULL)
1088 {
1089 joinstr[0] = sep;
1090 joinstr[1] = ' ';
c2f669a4 1091 *ptr = string_catn(*ptr, sizeptr, ptrptr, US"<", 1);
059ec3d9
PH
1092 }
1093
c2f669a4
JH
1094 *ptr = string_catn(*ptr, sizeptr, ptrptr, joinstr, 2);
1095 *ptr = string_cat (*ptr, sizeptr, ptrptr, s);
059ec3d9
PH
1096 }
1097
1098 if (new_smtp_port != NULL)
1099 {
1100 new_smtp_port[portptr] = 0;
1101 daemon_smtp_port = new_smtp_port;
1102 DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n",
1103 daemon_smtp_port);
1104 }
1105
1106 if (new_local_interfaces != NULL)
1107 {
1108 new_local_interfaces[ifaceptr] = 0;
1109 local_interfaces = new_local_interfaces;
1110 local_iface_source = US"-oX data";
1111 DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n",
1112 local_interfaces);
1113 }
1114 }
1115
1116 /* Create a list of default SMTP ports, to be used if local_interfaces
1117 contains entries without explict ports. First count the number of ports, then
1118 build a translated list in a vector. */
1119
1120 list = daemon_smtp_port;
1121 sep = 0;
55414b25 1122 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
059ec3d9
PH
1123 pct++;
1124 default_smtp_port = store_get((pct+1) * sizeof(int));
1125 list = daemon_smtp_port;
1126 sep = 0;
1127 for (pct = 0;
55414b25 1128 (s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size));
059ec3d9
PH
1129 pct++)
1130 {
1131 if (isdigit(*s))
1132 {
1133 uschar *end;
1134 default_smtp_port[pct] = Ustrtol(s, &end, 0);
1135 if (end != s + Ustrlen(s))
1136 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s);
1137 }
1138 else
1139 {
1140 struct servent *smtp_service = getservbyname(CS s, "tcp");
071c51f7 1141 if (!smtp_service)
059ec3d9
PH
1142 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1143 default_smtp_port[pct] = ntohs(smtp_service->s_port);
1144 }
1145 }
1146 default_smtp_port[pct] = 0;
1147
071c51f7
JH
1148 /* Check the list of TLS-on-connect ports and do name lookups if needed */
1149
1150 list = tls_in.on_connect_ports;
1151 sep = 0;
1152 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1153 if (!isdigit(*s))
1154 {
1155 list = tls_in.on_connect_ports;
1156 tls_in.on_connect_ports = NULL;
1157 sep = 0;
1158 while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1159 {
1160 if (!isdigit(*s))
1161 {
1162 struct servent *smtp_service = getservbyname(CS s, "tcp");
1163 if (!smtp_service)
1164 log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s);
1165 s= string_sprintf("%d", (int)ntohs(smtp_service->s_port));
1166 }
1167 tls_in.on_connect_ports = string_append_listele(tls_in.on_connect_ports,
1168 ':', s);
1169 }
1170 break;
1171 }
1172
059ec3d9
PH
1173 /* Create the list of local interfaces, possibly with ports included. This
1174 list may contain references to 0.0.0.0 and ::0 as wildcards. These special
1175 values are converted below. */
1176
1177 addresses = host_build_ifacelist(local_interfaces, local_iface_source);
1178
1179 /* In the list of IP addresses, convert 0.0.0.0 into an empty string, and ::0
1180 into the string ":". We use these to recognize wildcards in IPv4 and IPv6. In
1181 fact, many IP stacks recognize 0.0.0.0 and ::0 and handle them as wildcards
1182 anyway, but we need to know which are the wildcard addresses, and the shorter
1183 strings are neater.
1184
1185 In the same scan, fill in missing port numbers from the default list. When
1186 there is more than one item in the list, extra items are created. */
1187
1188 for (ipa = addresses; ipa != NULL; ipa = ipa->next)
1189 {
1190 int i;
1191
1192 if (Ustrcmp(ipa->address, "0.0.0.0") == 0) ipa->address[0] = 0;
1193 else if (Ustrcmp(ipa->address, "::0") == 0)
1194 {
1195 ipa->address[0] = ':';
1196 ipa->address[1] = 0;
1197 }
1198
1199 if (ipa->port > 0) continue;
1200
1201 if (daemon_smtp_port[0] <= 0)
1202 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface "
1203 "%s and daemon_smtp_port is unset; cannot start daemon",
1204 (ipa->address[0] == 0)? US"\"all IPv4\"" :
1205 (ipa->address[1] == 0)? US"\"all IPv6\"" : ipa->address);
1206 ipa->port = default_smtp_port[0];
1207 for (i = 1; default_smtp_port[i] > 0; i++)
1208 {
1209 ip_address_item *new = store_get(sizeof(ip_address_item));
1210 memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1);
1211 new->port = default_smtp_port[i];
1212 new->next = ipa->next;
1213 ipa->next = new;
1214 ipa = new;
1215 }
1216 }
1217
1218 /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6
1219 wildcard for the same port, ensure that (a) they are together and (b) the
1220 IPv6 address comes first. This makes handling the messy features easier, and
1221 also simplifies the construction of the "daemon started" log line. */
1222
1223 pipa = &addresses;
1224 for (ipa = addresses; ipa != NULL; pipa = &(ipa->next), ipa = ipa->next)
1225 {
1226 ip_address_item *ipa2;
1227
1228 /* Handle an IPv4 wildcard */
1229
1230 if (ipa->address[0] == 0)
1231 {
1232 for (ipa2 = ipa; ipa2->next != NULL; ipa2 = ipa2->next)
1233 {
1234 ip_address_item *ipa3 = ipa2->next;
1235 if (ipa3->address[0] == ':' &&
1236 ipa3->address[1] == 0 &&
1237 ipa3->port == ipa->port)
1238 {
1239 ipa2->next = ipa3->next;
1240 ipa3->next = ipa;
1241 *pipa = ipa3;
1242 break;
1243 }
1244 }
1245 }
1246
1247 /* Handle an IPv6 wildcard. */
1248
1249 else if (ipa->address[0] == ':' && ipa->address[1] == 0)
1250 {
1251 for (ipa2 = ipa; ipa2->next != NULL; ipa2 = ipa2->next)
1252 {
1253 ip_address_item *ipa3 = ipa2->next;
1254 if (ipa3->address[0] == 0 && ipa3->port == ipa->port)
1255 {
1256 ipa2->next = ipa3->next;
1257 ipa3->next = ipa->next;
1258 ipa->next = ipa3;
1259 ipa = ipa3;
1260 break;
1261 }
1262 }
1263 }
1264 }
1265
1266 /* Get a vector to remember all the sockets in */
1267
1268 for (ipa = addresses; ipa != NULL; ipa = ipa->next)
1269 listen_socket_count++;
96f5fe4c 1270 listen_sockets = store_get(sizeof(int) * listen_socket_count);
059ec3d9 1271
9ee44efb
PP
1272 } /* daemon_listen but not inetd_wait_mode */
1273
1274if (daemon_listen)
1275 {
1276
059ec3d9
PH
1277 /* Do a sanity check on the max connects value just to save us from getting
1278 a huge amount of store. */
1279
1280 if (smtp_accept_max > 4095) smtp_accept_max = 4096;
1281
1282 /* There's no point setting smtp_accept_queue unless it is less than the max
1283 connects limit. The configuration reader ensures that the max is set if the
1284 queue-only option is set. */
1285
1286 if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0;
1287
1288 /* Get somewhere to keep the list of SMTP accepting pids if we are keeping
1289 track of them for total number and queue/host limits. */
1290
1291 if (smtp_accept_max > 0)
1292 {
1293 int i;
1294 smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot));
1295 for (i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot;
1296 }
1297 }
1298
76a2d7ba
PH
1299/* The variable background_daemon is always false when debugging, but
1300can also be forced false in order to keep a non-debugging daemon in the
1301foreground. If background_daemon is true, close all open file descriptors that
9ee44efb
PP
1302we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also
1303do this for inetd_wait mode.
76a2d7ba
PH
1304
1305This is protection against any called functions (in libraries, or in
1306Perl, or whatever) that think they can write to stderr (or stdout). Before this
1307was added, it was quite likely that an SMTP connection would use one of these
1308file descriptors, in which case writing random stuff to it caused chaos.
1309
1310Then disconnect from the controlling terminal, Most modern Unixes seem to have
1311setsid() for getting rid of the controlling terminal. For any OS that doesn't,
1312setsid() can be #defined as a no-op, or as something else. */
059ec3d9 1313
9ee44efb 1314if (background_daemon || inetd_wait_mode)
059ec3d9 1315 {
76a2d7ba
PH
1316 log_close_all(); /* Just in case anything was logged earlier */
1317 search_tidyup(); /* Just in case any were used in reading the config. */
f1e894f3
PH
1318 (void)close(0); /* Get rid of stdin/stdout/stderr */
1319 (void)close(1);
1320 (void)close(2);
8e669ac1 1321 exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */
059ec3d9 1322 log_stderr = NULL; /* So no attempt to copy paniclog output */
9ee44efb 1323 }
059ec3d9 1324
9ee44efb
PP
1325if (background_daemon)
1326 {
059ec3d9 1327 /* If the parent process of this one has pid == 1, we are re-initializing the
8e669ac1 1328 daemon as the result of a SIGHUP. In this case, there is no need to do
76a2d7ba
PH
1329 anything, because the controlling terminal has long gone. Otherwise, fork, in
1330 case current process is a process group leader (see 'man setsid' for an
1331 explanation) before calling setsid(). */
059ec3d9
PH
1332
1333 if (getppid() != 1)
1334 {
1335 pid_t pid = fork();
1336 if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1337 "fork() failed when starting daemon: %s", strerror(errno));
1338 if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */
1339 (void)setsid(); /* release controlling terminal */
1340 }
1341 }
1342
1343/* We are now in the disconnected, daemon process (unless debugging). Set up
1344the listening sockets if required. */
1345
9ee44efb 1346if (daemon_listen && !inetd_wait_mode)
059ec3d9
PH
1347 {
1348 int sk;
059ec3d9
PH
1349 ip_address_item *ipa;
1350
1351 /* For each IP address, create a socket, bind it to the appropriate port, and
1352 start listening. See comments above about IPv6 sockets that may or may not
1353 accept IPv4 calls when listening on all interfaces. We also have to cope with
1354 the case of a system with IPv6 libraries, but no IPv6 support in the kernel.
1355 listening, provided a wildcard IPv4 socket for the same port follows. */
1356
1357 for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
1358 {
1359 BOOL wildcard;
1360 ip_address_item *ipa2;
059ec3d9
PH
1361 int af;
1362
1363 if (Ustrchr(ipa->address, ':') != NULL)
1364 {
1365 af = AF_INET6;
1366 wildcard = ipa->address[1] == 0;
1367 }
1368 else
1369 {
1370 af = AF_INET;
1371 wildcard = ipa->address[0] == 0;
1372 }
1373
96f5fe4c 1374 if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0)
059ec3d9
PH
1375 {
1376 if (check_special_case(0, addresses, ipa, FALSE))
1377 {
1378 log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard "
1379 "listening (%s): will use IPv4", strerror(errno));
1380 goto SKIP_SOCKET;
1381 }
1382 log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
1383 (af == AF_INET6)? '6' : '4', strerror(errno));
1384 }
1385
1386 /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is
1387 available. Just log failure (can get protocol not available, just like
1388 socket creation can). */
1389
1390 #ifdef IPV6_V6ONLY
1391 if (af == AF_INET6 && wildcard &&
1392 setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, (char *)(&on),
1393 sizeof(on)) < 0)
1394 log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard "
1395 "socket failed (%s): carrying on without it", strerror(errno));
1396 #endif /* IPV6_V6ONLY */
1397
1398 /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
1399 is being handled. Without this, a connection will prevent reuse of the
1400 smtp port for listening. */
1401
1402 if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR,
1403 (uschar *)(&on), sizeof(on)) < 0)
1404 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket "
1405 "failed when starting daemon: %s", strerror(errno));
1406
1407 /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to
1408 disable this because it breaks some broken clients. */
1409
1410 if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY,
1411 (uschar *)(&on), sizeof(on));
1412
1413 /* Now bind the socket to the required port; if Exim is being restarted
1414 it may not always be possible to bind immediately, even with SO_REUSEADDR
1415 set, so try 10 times, waiting between each try. After 10 failures, we give
1416 up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and
1417 we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard
1418 address for the same port, ignore the error on the grounds that we must be
1419 in a system where the IPv6 socket accepts both kinds of call. This is
1420 necessary for (some release of) USAGI Linux; other IP stacks fail at the
1421 listen() stage instead. */
1422
1423 for(;;)
1424 {
1425 uschar *msg, *addr;
1426 if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break;
1427 if (check_special_case(errno, addresses, ipa, TRUE))
1428 {
1429 DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 "
1430 "listen() success; EADDRINUSE ignored\n");
f1e894f3 1431 (void)close(listen_sockets[sk]);
059ec3d9
PH
1432 goto SKIP_SOCKET;
1433 }
1434 msg = US strerror(errno);
1435 addr = wildcard? ((af == AF_INET6)? US"(any IPv6)" : US"(any IPv4)") :
1436 ipa->address;
4aee0225 1437 if (daemon_startup_retries <= 0)
059ec3d9
PH
1438 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1439 "socket bind() to port %d for address %s failed: %s: "
1440 "daemon abandoned", ipa->port, addr, msg);
1441 log_write(0, LOG_MAIN, "socket bind() to port %d for address %s "
4aee0225
PH
1442 "failed: %s: waiting %s before trying again (%d more %s)",
1443 ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep),
1444 daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try");
1445 daemon_startup_retries--;
1446 sleep(daemon_startup_sleep);
059ec3d9
PH
1447 }
1448
1449 DEBUG(D_any)
059ec3d9
PH
1450 if (wildcard)
1451 debug_printf("listening on all interfaces (IPv%c) port %d\n",
fb05276a 1452 af == AF_INET6 ? '6' : '4', ipa->port);
059ec3d9
PH
1453 else
1454 debug_printf("listening on %s port %d\n", ipa->address, ipa->port);
fb05276a
JH
1455
1456#ifdef TCP_FASTOPEN
1457 if (setsockopt(listen_sockets[sk], SOL_TCP, TCP_FASTOPEN, &smtp_connect_backlog,
1458 sizeof(smtp_connect_backlog)))
1459 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set socket FASTOPEN: %s",
1460 strerror(errno));
1461#endif
059ec3d9
PH
1462
1463 /* Start listening on the bound socket, establishing the maximum backlog of
1464 connections that is allowed. On success, continue to the next address. */
1465
1466 if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0) continue;
1467
1468 /* Listening has failed. In an IPv6 environment, as for bind(), if listen()
1469 fails with the error EADDRINUSE and we are doing IPv4 wildcard listening
1470 and there was a previous successful IPv6 wildcard listen on the same port,
1471 we want to ignore the error on the grounds that we must be in a system
1472 where the IPv6 socket accepts both kinds of call. */
1473
1474 if (!check_special_case(errno, addresses, ipa, TRUE))
1475 log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s",
fb05276a
JH
1476 wildcard
1477 ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address,
059ec3d9
PH
1478 strerror(errno));
1479
1480 DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 "
1481 "listen() success; EADDRINUSE ignored\n");
f1e894f3 1482 (void)close(listen_sockets[sk]);
059ec3d9
PH
1483
1484 /* Come here if there has been a problem with the socket which we
1485 are going to ignore. We remove the address from the chain, and back up the
1486 counts. */
1487
1488 SKIP_SOCKET:
1489 sk--; /* Back up the count */
1490 listen_socket_count--; /* Reduce the total */
1491 if (ipa == addresses) addresses = ipa->next; else
1492 {
1493 for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next);
1494 ipa2->next = ipa->next;
1495 ipa = ipa2;
1496 }
1497 } /* End of bind/listen loop for each address */
1498 } /* End of setup for listening */
1499
1500
1501/* If we are not listening, we want to write a pid file only if -oP was
1502explicitly given. */
1503
1504else if (override_pid_file_path == NULL) write_pid = FALSE;
1505
1506/* Write the pid to a known file for assistance in identification, if required.
1507We do this before giving up root privilege, because on some systems it is
1508necessary to be root in order to write into the pid file directory. There's
1509nothing to stop multiple daemons running, as long as no more than one listens
1510on a given TCP/IP port on the same interface(s). However, in these
1511circumstances it gets far too complicated to mess with pid file names
1512automatically. Consequently, Exim 4 writes a pid file only
1513
1514 (a) When running in the test harness, or
1515 (b) When -bd is used and -oX is not used, or
1516 (c) When -oP is used to supply a path.
1517
1518The variable daemon_write_pid is used to control this. */
1519
1520if (running_in_test_harness || write_pid)
1521 {
1522 FILE *f;
1523
1524 if (override_pid_file_path != NULL)
1525 pid_file_path = override_pid_file_path;
1526
1527 if (pid_file_path[0] == 0)
1528 pid_file_path = string_sprintf("%s/exim-daemon.pid", spool_directory);
1529
2632889e 1530 f = modefopen(pid_file_path, "wb", 0644);
059ec3d9
PH
1531 if (f != NULL)
1532 {
ff790e47 1533 (void)fprintf(f, "%d\n", (int)getpid());
ff790e47 1534 (void)fclose(f);
059ec3d9
PH
1535 DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path);
1536 }
1537 else
1538 {
1539 DEBUG(D_any)
1540 debug_printf("%s\n", string_open_failed(errno, "pid file %s",
1541 pid_file_path));
1542 }
1543 }
1544
1545/* Set up the handler for SIGHUP, which causes a restart of the daemon. */
1546
1547sighup_seen = FALSE;
1548signal(SIGHUP, sighup_handler);
1549
1550/* Give up root privilege at this point (assuming that exim_uid and exim_gid
1551are not root). The third argument controls the running of initgroups().
1552Normally we do this, in order to set up the groups for the Exim user. However,
1553if we are not root at this time - some odd installations run that way - we
1554cannot do this. */
1555
1556exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon");
1557
ebeaf996
PH
1558/* Update the originator_xxx fields so that received messages as listed as
1559coming from Exim, not whoever started the daemon. */
1560
1561originator_uid = exim_uid;
1562originator_gid = exim_gid;
1563originator_login = ((pw = getpwuid(exim_uid)) != NULL)?
1564 string_copy_malloc(US pw->pw_name) : US"exim";
1565
059ec3d9
PH
1566/* Get somewhere to keep the list of queue-runner pids if we are keeping track
1567of them (and also if we are doing queue runs). */
1568
0cd5fd23 1569if (queue_interval > 0 && local_queue_run_max > 0)
059ec3d9
PH
1570 {
1571 int i;
0cd5fd23
JH
1572 queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t));
1573 for (i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0;
059ec3d9
PH
1574 }
1575
1576/* Set up the handler for termination of child processes. */
1577
1578sigchld_seen = FALSE;
7d468ab8 1579os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
059ec3d9
PH
1580
1581/* If we are to run the queue periodically, pretend the alarm has just gone
1582off. This will cause the first queue-runner to get kicked off straight away. */
1583
1584sigalrm_seen = (queue_interval > 0);
1585
1586/* Log the start up of a daemon - at least one of listening or queue running
1587must be set up. */
1588
9ee44efb
PP
1589if (inetd_wait_mode)
1590 {
1591 uschar *p = big_buffer;
1592
1593 if (inetd_wait_timeout >= 0)
1594 sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout);
1595 else
1596 sprintf(CS p, "with no wait timeout");
1597
1598 log_write(0, LOG_MAIN,
1599 "exim %s daemon started: pid=%d, launched with listening socket, %s",
1600 version_string, getpid(), big_buffer);
2f21487f 1601 set_process_info("daemon(%s): pre-listening socket", version_string);
9ee44efb
PP
1602
1603 /* set up the timeout logic */
1604 sigalrm_seen = 1;
1605 }
1606
1607else if (daemon_listen)
059ec3d9
PH
1608 {
1609 int i, j;
1610 int smtp_ports = 0;
1611 int smtps_ports = 0;
e37f8a84
JH
1612 ip_address_item * ipa;
1613 uschar * p = big_buffer;
1614 uschar * qinfo = queue_interval > 0
1615 ? string_sprintf("-q%s", readconf_printtime(queue_interval))
1616 : US"no queue runs";
059ec3d9
PH
1617
1618 /* Build a list of listening addresses in big_buffer, but limit it to 10
1619 items. The style is for backwards compatibility.
1620
1621 It is now possible to have some ports listening for SMTPS (the old,
1622 deprecated protocol that starts TLS without using STARTTLS), and others
1623 listening for standard SMTP. Keep their listings separate. */
1624
1625 for (j = 0; j < 2; j++)
1626 {
e37f8a84 1627 for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next)
059ec3d9
PH
1628 {
1629 /* First time round, look for SMTP ports; second time round, look for
1630 SMTPS ports. For the first one of each, insert leading text. */
1631
1632 if (host_is_tls_on_connect_port(ipa->port) == (j > 0))
1633 {
e37f8a84
JH
1634 if (j == 0)
1635 {
1636 if (smtp_ports++ == 0)
059ec3d9
PH
1637 {
1638 memcpy(p, "SMTP on", 8);
1639 p += 7;
1640 }
e37f8a84
JH
1641 }
1642 else
1643 {
1644 if (smtps_ports++ == 0)
059ec3d9
PH
1645 {
1646 (void)sprintf(CS p, "%sSMTPS on",
e37f8a84
JH
1647 smtp_ports == 0 ? "" : " and for ");
1648 while (*p) p++;
059ec3d9 1649 }
e37f8a84 1650 }
059ec3d9
PH
1651
1652 /* Now the information about the port (and sometimes interface) */
1653
1654 if (ipa->address[0] == ':' && ipa->address[1] == 0)
1655 {
1656 if (ipa->next != NULL && ipa->next->address[0] == 0 &&
1657 ipa->next->port == ipa->port)
1658 {
1659 (void)sprintf(CS p, " port %d (IPv6 and IPv4)", ipa->port);
1660 ipa = ipa->next;
1661 }
1662 else if (ipa->v6_include_v4)
1663 (void)sprintf(CS p, " port %d (IPv6 with IPv4)", ipa->port);
1664 else
1665 (void)sprintf(CS p, " port %d (IPv6)", ipa->port);
1666 }
1667 else if (ipa->address[0] == 0)
1668 (void)sprintf(CS p, " port %d (IPv4)", ipa->port);
1669 else
1670 (void)sprintf(CS p, " [%s]:%d", ipa->address, ipa->port);
1671 while (*p != 0) p++;
1672 }
1673 }
1674
e37f8a84 1675 if (ipa)
059ec3d9
PH
1676 {
1677 memcpy(p, " ...", 5);
1678 p += 4;
1679 }
1680 }
1681
1682 log_write(0, LOG_MAIN,
1683 "exim %s daemon started: pid=%d, %s, listening for %s",
1684 version_string, getpid(), qinfo, big_buffer);
44915474
JH
1685 set_process_info("daemon(%s): %s, listening for %s",
1686 version_string, qinfo, big_buffer);
059ec3d9
PH
1687 }
1688
1689else
1690 {
44915474
JH
1691 uschar * s = *queue_name
1692 ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval))
1693 : string_sprintf("-q%s", readconf_printtime(queue_interval));
059ec3d9 1694 log_write(0, LOG_MAIN,
44915474
JH
1695 "exim %s daemon started: pid=%d, %s, not listening for SMTP",
1696 version_string, getpid(), s);
1697 set_process_info("daemon(%s): %s, not listening", version_string, s);
059ec3d9
PH
1698 }
1699
476be7e2
JH
1700/* Do any work it might be useful to amortize over our children
1701(eg: compile regex) */
1702
476be7e2
JH
1703dns_pattern_init();
1704
1705#ifdef WITH_CONTENT_SCAN
1706malware_init();
1707#endif
059ec3d9
PH
1708
1709/* Close the log so it can be renamed and moved. In the few cases below where
1710this long-running process writes to the log (always exceptional conditions), it
1711closes the log afterwards, for the same reason. */
1712
1713log_close_all();
1714
1715DEBUG(D_any) debug_print_ids(US"daemon running with");
1716
1717/* Any messages accepted via this route are going to be SMTP. */
1718
1719smtp_input = TRUE;
1720
1721/* Enter the never-ending loop... */
1722
1723for (;;)
1724 {
1725 #if HAVE_IPV6
1726 struct sockaddr_in6 accepted;
1727 #else
1728 struct sockaddr_in accepted;
1729 #endif
1730
cf73943b 1731 EXIM_SOCKLEN_T len;
059ec3d9
PH
1732 pid_t pid;
1733
1734 /* This code is placed first in the loop, so that it gets obeyed at the
9ee44efb
PP
1735 start, before the first wait, for the queue-runner case, so that the first
1736 one can be started immediately.
1737
1738 The other option is that we have an inetd wait timeout specified to -bw. */
059ec3d9
PH
1739
1740 if (sigalrm_seen)
1741 {
9ee44efb
PP
1742 if (inetd_wait_timeout > 0)
1743 {
1744 time_t resignal_interval = inetd_wait_timeout;
1745
1746 if (last_connection_time == (time_t)0)
1747 {
1748 DEBUG(D_any)
1749 debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n");
1750 }
1751 else
1752 {
1753 time_t now = time(NULL);
1754 if (now == (time_t)-1)
1755 {
1756 DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno));
1757 }
1758 else
1759 {
1760 if ((now - last_connection_time) >= inetd_wait_timeout)
1761 {
1762 DEBUG(D_any)
1763 debug_printf("inetd wait timeout %d expired, ending daemon\n",
1764 inetd_wait_timeout);
1765 log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n",
1766 version_string);
1767 exit(EXIT_SUCCESS);
1768 }
1769 else
1770 {
1771 resignal_interval -= (now - last_connection_time);
1772 }
1773 }
1774 }
059ec3d9 1775
9ee44efb
PP
1776 sigalrm_seen = FALSE;
1777 alarm(resignal_interval);
1778 }
059ec3d9 1779
9ee44efb 1780 else
059ec3d9 1781 {
9ee44efb 1782 DEBUG(D_any) debug_printf("SIGALRM received\n");
8e669ac1 1783
9ee44efb
PP
1784 /* Do a full queue run in a child process, if required, unless we already
1785 have enough queue runners on the go. If we are not running as root, a
1786 re-exec is required. */
059ec3d9 1787
9ee44efb 1788 if (queue_interval > 0 &&
0cd5fd23 1789 (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max))
9ee44efb
PP
1790 {
1791 if ((pid = fork()) == 0)
1792 {
1793 int sk;
3d235903 1794
9ee44efb
PP
1795 DEBUG(D_any) debug_printf("Starting queue-runner: pid %d\n",
1796 (int)getpid());
8e669ac1 1797
9ee44efb
PP
1798 /* Disable debugging if it's required only for the daemon process. We
1799 leave the above message, because it ties up with the "child ended"
1800 debugging messages. */
059ec3d9 1801
9ee44efb 1802 if (debug_daemon) debug_selector = 0;
059ec3d9 1803
9ee44efb 1804 /* Close any open listening sockets in the child */
059ec3d9 1805
9ee44efb
PP
1806 for (sk = 0; sk < listen_socket_count; sk++)
1807 (void)close(listen_sockets[sk]);
059ec3d9 1808
9ee44efb 1809 /* Reset SIGHUP and SIGCHLD in the child in both cases. */
059ec3d9 1810
9ee44efb
PP
1811 signal(SIGHUP, SIG_DFL);
1812 signal(SIGCHLD, SIG_DFL);
059ec3d9 1813
9ee44efb
PP
1814 /* Re-exec if privilege has been given up, unless deliver_drop_
1815 privilege is set. Reset SIGALRM before exec(). */
4fbcfc2e 1816
9ee44efb 1817 if (geteuid() != root_uid && !deliver_drop_privilege)
4fbcfc2e 1818 {
9ee44efb
PP
1819 uschar opt[8];
1820 uschar *p = opt;
1821 uschar *extra[5];
1822 int extracount = 1;
1823
1824 signal(SIGALRM, SIG_DFL);
1825 *p++ = '-';
1826 *p++ = 'q';
1827 if (queue_2stage) *p++ = 'q';
1828 if (queue_run_first_delivery) *p++ = 'i';
1829 if (queue_run_force) *p++ = 'f';
1830 if (deliver_force_thaw) *p++ = 'f';
1831 if (queue_run_local) *p++ = 'l';
1832 *p = 0;
e37f8a84
JH
1833 extra[0] = queue_name
1834 ? string_sprintf("%sG%s", opt, queue_name) : opt;
9ee44efb
PP
1835
1836 /* If -R or -S were on the original command line, ensure they get
1837 passed on. */
1838
e37f8a84 1839 if (deliver_selectstring)
9ee44efb 1840 {
e37f8a84 1841 extra[extracount++] = deliver_selectstring_regex ? US"-Rr" : US"-R";
9ee44efb
PP
1842 extra[extracount++] = deliver_selectstring;
1843 }
1844
e37f8a84 1845 if (deliver_selectstring_sender)
9ee44efb 1846 {
e37f8a84
JH
1847 extra[extracount++] = deliver_selectstring_sender_regex
1848 ? US"-Sr" : US"-S";
9ee44efb
PP
1849 extra[extracount++] = deliver_selectstring_sender;
1850 }
1851
1852 /* Overlay this process with a new execution. */
1853
1854 (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, TRUE, extracount,
1855 extra[0], extra[1], extra[2], extra[3], extra[4]);
1856
1857 /* Control never returns here. */
4fbcfc2e
PH
1858 }
1859
9ee44efb 1860 /* No need to re-exec; SIGALRM remains set to the default handler */
059ec3d9 1861
9ee44efb
PP
1862 queue_run(NULL, NULL, FALSE);
1863 _exit(EXIT_SUCCESS);
059ec3d9
PH
1864 }
1865
9ee44efb 1866 if (pid < 0)
059ec3d9 1867 {
9ee44efb
PP
1868 log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner "
1869 "process failed: %s", strerror(errno));
1870 log_close_all();
1871 }
1872 else
1873 {
1874 int i;
0cd5fd23 1875 for (i = 0; i < local_queue_run_max; ++i)
9ee44efb
PP
1876 if (queue_pid_slots[i] <= 0)
1877 {
1878 queue_pid_slots[i] = pid;
1879 queue_run_count++;
1880 break;
1881 }
9ee44efb
PP
1882 DEBUG(D_any) debug_printf("%d queue-runner process%s running\n",
1883 queue_run_count, (queue_run_count == 1)? "" : "es");
059ec3d9 1884 }
059ec3d9 1885 }
059ec3d9 1886
9ee44efb 1887 /* Reset the alarm clock */
059ec3d9 1888
9ee44efb
PP
1889 sigalrm_seen = FALSE;
1890 alarm(queue_interval);
1891 }
1892
1893 } /* sigalrm_seen */
059ec3d9
PH
1894
1895
1896 /* Sleep till a connection happens if listening, and handle the connection if
1897 that is why we woke up. The FreeBSD operating system requires the use of
1898 select() before accept() because the latter function is not interrupted by
1899 a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other
1900 OS do notice signals in accept() but it does no harm to have the select()
1901 in for all of them - and it won't then be a lurking problem for ports to
1902 new OS. In fact, the later addition of listening on specific interfaces only
1903 requires this way of working anyway. */
1904
1905 if (daemon_listen)
1906 {
bb6e88ff 1907 int sk, lcount, select_errno;
059ec3d9
PH
1908 int max_socket = 0;
1909 BOOL select_failed = FALSE;
1910 fd_set select_listen;
1911
1912 FD_ZERO(&select_listen);
1913 for (sk = 0; sk < listen_socket_count; sk++)
1914 {
1915 FD_SET(listen_sockets[sk], &select_listen);
1916 if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk];
1917 }
1918
1919 DEBUG(D_any) debug_printf("Listening...\n");
8e669ac1
PH
1920
1921 /* In rare cases we may have had a SIGCHLD signal in the time between
1922 setting the handler (below) and getting back here. If so, pretend that the
7d468ab8 1923 select() was interrupted so that we reap the child. This might still leave
8e669ac1 1924 a small window when a SIGCHLD could get lost. However, since we use SIGCHLD
7d468ab8
PH
1925 only to do the reaping more quickly, it shouldn't result in anything other
1926 than a delay until something else causes a wake-up. */
1927
1928 if (sigchld_seen)
1929 {
1930 lcount = -1;
8e669ac1 1931 errno = EINTR;
7d468ab8
PH
1932 }
1933 else
8e669ac1 1934 {
7d468ab8
PH
1935 lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen,
1936 NULL, NULL, NULL);
8e669ac1 1937 }
059ec3d9 1938
7d468ab8 1939 if (lcount < 0)
059ec3d9
PH
1940 {
1941 select_failed = TRUE;
1942 lcount = 1;
1943 }
8e669ac1
PH
1944
1945 /* Clean up any subprocesses that may have terminated. We need to do this
1946 here so that smtp_accept_max_per_host works when a connection to that host
1947 has completed, and we are about to accept a new one. When this code was
1948 later in the sequence, a new connection could be rejected, even though an
1949 old one had just finished. Preserve the errno from any select() failure for
bb6e88ff 1950 the use of the common select/accept error processing below. */
8e669ac1 1951
bb6e88ff
PH
1952 select_errno = errno;
1953 handle_ending_processes();
8e669ac1
PH
1954 errno = select_errno;
1955
059ec3d9 1956 /* Loop for all the sockets that are currently ready to go. If select
7d468ab8
PH
1957 actually failed, we have set the count to 1 and select_failed=TRUE, so as
1958 to use the common error code for select/accept below. */
059ec3d9
PH
1959
1960 while (lcount-- > 0)
1961 {
1962 int accept_socket = -1;
1963 if (!select_failed)
1964 {
1965 for (sk = 0; sk < listen_socket_count; sk++)
1966 {
1967 if (FD_ISSET(listen_sockets[sk], &select_listen))
1968 {
cf73943b 1969 len = sizeof(accepted);
059ec3d9
PH
1970 accept_socket = accept(listen_sockets[sk],
1971 (struct sockaddr *)&accepted, &len);
1972 FD_CLR(listen_sockets[sk], &select_listen);
1973 break;
1974 }
1975 }
1976 }
1977
1978 /* If select or accept has failed and this was not caused by an
1979 interruption, log the incident and try again. With asymmetric TCP/IP
1980 routing errors such as "No route to network" have been seen here. Also
1981 "connection reset by peer" has been seen. These cannot be classed as
1982 disastrous errors, but they could fill up a lot of log. The code in smail
1983 crashes the daemon after 10 successive failures of accept, on the grounds
1984 that some OS fail continuously. Exim originally followed suit, but this
1985 appears to have caused problems. Now it just keeps going, but instead of
1986 logging each error, it batches them up when they are continuous. */
1987
1988 if (accept_socket < 0 && errno != EINTR)
1989 {
1990 if (accept_retry_count == 0)
1991 {
1992 accept_retry_errno = errno;
1993 accept_retry_select_failed = select_failed;
1994 }
1995 else
1996 {
1997 if (errno != accept_retry_errno ||
1998 select_failed != accept_retry_select_failed ||
1999 accept_retry_count >= 50)
2000 {
2001 log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0),
2002 "%d %s() failure%s: %s",
2003 accept_retry_count,
2004 accept_retry_select_failed? "select" : "accept",
2005 (accept_retry_count == 1)? "" : "s",
2006 strerror(accept_retry_errno));
2007 log_close_all();
2008 accept_retry_count = 0;
2009 accept_retry_errno = errno;
2010 accept_retry_select_failed = select_failed;
2011 }
2012 }
2013 accept_retry_count++;
2014 }
2015
2016 else
2017 {
2018 if (accept_retry_count > 0)
2019 {
2020 log_write(0, LOG_MAIN, "%d %s() failure%s: %s",
2021 accept_retry_count,
2022 accept_retry_select_failed? "select" : "accept",
2023 (accept_retry_count == 1)? "" : "s",
2024 strerror(accept_retry_errno));
2025 log_close_all();
2026 accept_retry_count = 0;
2027 }
2028 }
2029
2030 /* If select/accept succeeded, deal with the connection. */
2031
2032 if (accept_socket >= 0)
9ee44efb
PP
2033 {
2034 if (inetd_wait_timeout)
2035 last_connection_time = time(NULL);
059ec3d9
PH
2036 handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,
2037 (struct sockaddr *)&accepted);
9ee44efb 2038 }
059ec3d9
PH
2039 }
2040 }
2041
2042 /* If not listening, then just sleep for the queue interval. If we woke
2043 up early the last time for some other signal, it won't matter because
2044 the alarm signal will wake at the right time. This code originally used
2045 sleep() but it turns out that on the FreeBSD system, sleep() is not inter-
2046 rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily
2047 select() can be used as an interruptible sleep() on all versions of Unix. */
2048
2049 else
2050 {
2051 struct timeval tv;
2052 tv.tv_sec = queue_interval;
2053 tv.tv_usec = 0;
2054 select(0, NULL, NULL, NULL, &tv);
8e669ac1 2055 handle_ending_processes();
059ec3d9
PH
2056 }
2057
2058 /* Re-enable the SIGCHLD handler if it has been run. It can't do it
2059 for itself, because it isn't doing the waiting itself. */
2060
2061 if (sigchld_seen)
2062 {
2063 sigchld_seen = FALSE;
7d468ab8 2064 os_non_restarting_signal(SIGCHLD, main_sigchld_handler);
059ec3d9
PH
2065 }
2066
2067 /* Handle being woken by SIGHUP. We know at this point that the result
2068 of accept() has been dealt with, so we can re-exec exim safely, first
2069 closing the listening sockets so that they can be reused. Cancel any pending
2070 alarm in case it is just about to go off, and set SIGHUP to be ignored so
2071 that another HUP in quick succession doesn't clobber the new daemon before it
2072 gets going. All log files get closed by the close-on-exec flag; however, if
2073 the exec fails, we need to close the logs. */
2074
2075 if (sighup_seen)
2076 {
2077 int sk;
2078 log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon",
2079 getpid());
f1e894f3
PH
2080 for (sk = 0; sk < listen_socket_count; sk++)
2081 (void)close(listen_sockets[sk]);
059ec3d9
PH
2082 alarm(0);
2083 signal(SIGHUP, SIG_IGN);
2084 sighup_argv[0] = exim_path;
2085 exim_nullstd();
2086 execv(CS exim_path, (char *const *)sighup_argv);
2087 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s",
2088 getpid(), exim_path, strerror(errno));
2089 log_close_all();
2090 }
2091
2092 } /* End of main loop */
2093
2094/* Control never reaches here */
2095}
2096
071c51f7
JH
2097/* vi: aw ai sw=2
2098*/
059ec3d9 2099/* End of exim_daemon.c */