Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
f9ba5e22 | 5 | /* Copyright (c) University of Cambridge 1995 - 2018 */ |
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 | ||
16 | typedef 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 | |
4c04137d | 22 | expressions in assignments except as initializers in declarations). */ |
059ec3d9 | 23 | |
f2ed27cf | 24 | static smtp_slot empty_smtp_slot = { .pid = 0, .host_address = NULL }; |
059ec3d9 PH |
25 | |
26 | ||
27 | ||
28 | /************************************************* | |
29 | * Local static variables * | |
30 | *************************************************/ | |
31 | ||
cd59ab18 PP |
32 | static SIGNAL_BOOL sigchld_seen; |
33 | static SIGNAL_BOOL sighup_seen; | |
059ec3d9 PH |
34 | |
35 | static int accept_retry_count = 0; | |
36 | static int accept_retry_errno; | |
37 | static BOOL accept_retry_select_failed; | |
38 | ||
39 | static int queue_run_count = 0; | |
bb6e88ff PH |
40 | static pid_t *queue_pid_slots = NULL; |
41 | static smtp_slot *smtp_slots = NULL; | |
059ec3d9 PH |
42 | |
43 | static 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 | ||
53 | Argument: the signal number | |
54 | Returns: nothing | |
55 | */ | |
56 | ||
57 | static void | |
58 | sighup_handler(int sig) | |
59 | { | |
60 | sig = sig; /* Keep picky compilers happy */ | |
61 | sighup_seen = TRUE; | |
62 | signal(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 | |
72 | waiting here. If the signal is re-enabled, there will just be an | |
73 | infinite sequence of calls to this handler. The SIGCHLD signal is | |
74 | used just as a means of waking up the daemon so that it notices | |
75 | terminated subprocesses as soon as possible. | |
76 | ||
77 | Argument: the signal number | |
78 | Returns: nothing | |
79 | */ | |
80 | ||
81 | static void | |
82 | main_sigchld_handler(int sig) | |
83 | { | |
84 | sig = sig; /* Keep picky compilers happy */ | |
7d468ab8 | 85 | os_non_restarting_signal(SIGCHLD, SIG_DFL); |
059ec3d9 | 86 | sigchld_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 | ||
98 | Arguments: | |
99 | log_msg Text of message to be logged | |
100 | smtp_msg Text of SMTP error message | |
101 | was_errno The failing errno | |
102 | ||
103 | Returns: nothing | |
104 | */ | |
105 | ||
106 | static void | |
107 | never_error(uschar *log_msg, uschar *smtp_msg, int was_errno) | |
108 | { | |
52f12a7c JH |
109 | uschar *emsg = was_errno <= 0 |
110 | ? US"" : string_sprintf(": %s", strerror(was_errno)); | |
059ec3d9 | 111 | log_write(0, LOG_MAIN|LOG_PANIC, "%s%s", log_msg, emsg); |
52f12a7c | 112 | if (smtp_out) smtp_printf("421 %s\r\n", FALSE, smtp_msg); |
059ec3d9 PH |
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. | |
123 | If there are too many, give an error message and close down. Otherwise | |
124 | spin off a sub-process to handle the call. The list of listening sockets | |
125 | is required so that they can be closed in the sub-process. Take care not to | |
126 | leak store in this process - reset the stacking pool at the end. | |
127 | ||
128 | Arguments: | |
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 | ||
134 | Returns: nothing | |
135 | */ | |
136 | ||
137 | static void | |
138 | handle_smtp_call(int *listen_sockets, int listen_socket_count, | |
139 | int accept_socket, struct sockaddr *accepted) | |
140 | { | |
141 | pid_t pid; | |
142 | union sockaddr_46 interface_sockaddr; | |
36a3b041 | 143 | EXIM_SOCKLEN_T ifsize = sizeof(interface_sockaddr); |
059ec3d9 PH |
144 | int dup_accept_socket = -1; |
145 | int max_for_this_host = 0; | |
6c6d6e48 | 146 | int save_log_selector = *log_selector; |
b2bcdd35 | 147 | gstring * whofrom; |
059ec3d9 PH |
148 | |
149 | void *reset_point = store_get(0); | |
150 | ||
151 | /* Make the address available in ASCII representation, and also fish out | |
152 | the remote port. */ | |
153 | ||
154 | sender_host_address = host_ntoa(-1, accepted, NULL, &sender_host_port); | |
155 | DEBUG(D_any) debug_printf("Connection request from %s port %d\n", | |
156 | sender_host_address, sender_host_port); | |
157 | ||
158 | /* Set up the output stream, check the socket has duplicated, and set up the | |
159 | input stream. These operations fail only the exceptional circumstances. Note | |
160 | that never_error() won't use smtp_out if it is NULL. */ | |
161 | ||
f5d25c2b | 162 | if (!(smtp_out = fdopen(accept_socket, "wb"))) |
059ec3d9 PH |
163 | { |
164 | never_error(US"daemon: fdopen() for smtp_out failed", US"", errno); | |
165 | goto ERROR_RETURN; | |
166 | } | |
167 | ||
f5d25c2b | 168 | if ((dup_accept_socket = dup(accept_socket)) < 0) |
059ec3d9 PH |
169 | { |
170 | never_error(US"daemon: couldn't dup socket descriptor", | |
171 | US"Connection setup failed", errno); | |
172 | goto ERROR_RETURN; | |
173 | } | |
174 | ||
f5d25c2b | 175 | if (!(smtp_in = fdopen(dup_accept_socket, "rb"))) |
059ec3d9 PH |
176 | { |
177 | never_error(US"daemon: fdopen() for smtp_in failed", | |
178 | US"Connection setup failed", errno); | |
179 | goto ERROR_RETURN; | |
180 | } | |
181 | ||
520de300 PH |
182 | /* Get the data for the local interface address. Panic for most errors, but |
183 | "connection reset by peer" just means the connection went away. */ | |
059ec3d9 PH |
184 | |
185 | if (getsockname(accept_socket, (struct sockaddr *)(&interface_sockaddr), | |
186 | &ifsize) < 0) | |
187 | { | |
520de300 PH |
188 | log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC), |
189 | "getsockname() failed: %s", strerror(errno)); | |
925ac8e4 | 190 | smtp_printf("421 Local problem: getsockname() failed; please try again later\r\n", FALSE); |
059ec3d9 PH |
191 | goto ERROR_RETURN; |
192 | } | |
193 | ||
194 | interface_address = host_ntoa(-1, &interface_sockaddr, NULL, &interface_port); | |
195 | DEBUG(D_interface) debug_printf("interface address=%s port=%d\n", | |
196 | interface_address, interface_port); | |
197 | ||
198 | /* Build a string identifying the remote host and, if requested, the port and | |
199 | the local interface data. This is for logging; at the end of this function the | |
200 | memory is reclaimed. */ | |
201 | ||
b2bcdd35 | 202 | whofrom = string_append(NULL, 3, "[", sender_host_address, "]"); |
059ec3d9 | 203 | |
6c6d6e48 | 204 | if (LOGGING(incoming_port)) |
52f12a7c | 205 | whofrom = string_fmt_append(whofrom, ":%d", sender_host_port); |
059ec3d9 | 206 | |
6c6d6e48 | 207 | if (LOGGING(incoming_interface)) |
52f12a7c JH |
208 | whofrom = string_fmt_append(whofrom, " I=[%s]:%d", |
209 | interface_address, interface_port); | |
059ec3d9 | 210 | |
acec9514 | 211 | (void) string_from_gstring(whofrom); /* Terminate the newly-built string */ |
059ec3d9 PH |
212 | |
213 | /* Check maximum number of connections. We do not check for reserved | |
214 | connections or unacceptable hosts here. That is done in the subprocess because | |
215 | it might take some time. */ | |
216 | ||
217 | if (smtp_accept_max > 0 && smtp_accept_count >= smtp_accept_max) | |
218 | { | |
219 | DEBUG(D_any) debug_printf("rejecting SMTP connection: count=%d max=%d\n", | |
220 | smtp_accept_count, smtp_accept_max); | |
221 | smtp_printf("421 Too many concurrent SMTP connections; " | |
925ac8e4 | 222 | "please try again later.\r\n", FALSE); |
059ec3d9 PH |
223 | log_write(L_connection_reject, |
224 | LOG_MAIN, "Connection from %s refused: too many connections", | |
acec9514 | 225 | whofrom->s); |
059ec3d9 PH |
226 | goto ERROR_RETURN; |
227 | } | |
228 | ||
229 | /* If a load limit above which only reserved hosts are acceptable is defined, | |
230 | get the load average here, and if there are in fact no reserved hosts, do | |
231 | the test right away (saves a fork). If there are hosts, do the check in the | |
232 | subprocess because it might take time. */ | |
233 | ||
234 | if (smtp_load_reserve >= 0) | |
235 | { | |
8669f003 | 236 | load_average = OS_GETLOADAVG(); |
059ec3d9 PH |
237 | if (smtp_reserve_hosts == NULL && load_average > smtp_load_reserve) |
238 | { | |
239 | DEBUG(D_any) debug_printf("rejecting SMTP connection: load average = %.2f\n", | |
240 | (double)load_average/1000.0); | |
925ac8e4 | 241 | smtp_printf("421 Too much load; please try again later.\r\n", FALSE); |
059ec3d9 PH |
242 | log_write(L_connection_reject, |
243 | LOG_MAIN, "Connection from %s refused: load average = %.2f", | |
acec9514 | 244 | whofrom->s, (double)load_average/1000.0); |
059ec3d9 PH |
245 | goto ERROR_RETURN; |
246 | } | |
247 | } | |
248 | ||
249 | /* Check that one specific host (strictly, IP address) is not hogging | |
250 | resources. This is done here to prevent a denial of service attack by someone | |
251 | forcing you to fork lots of times before denying service. The value of | |
252 | smtp_accept_max_per_host is a string which is expanded. This makes it possible | |
253 | to provide host-specific limits according to $sender_host address, but because | |
254 | this is in the daemon mainline, only fast expansions (such as inline address | |
255 | checks) should be used. The documentation is full of warnings. */ | |
256 | ||
257 | if (smtp_accept_max_per_host != NULL) | |
258 | { | |
259 | uschar *expanded = expand_string(smtp_accept_max_per_host); | |
260 | if (expanded == NULL) | |
261 | { | |
8768d548 | 262 | if (!f.expand_string_forcedfail) |
059ec3d9 | 263 | log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host " |
acec9514 | 264 | "failed for %s: %s", whofrom->s, expand_string_message); |
059ec3d9 PH |
265 | } |
266 | /* For speed, interpret a decimal number inline here */ | |
267 | else | |
268 | { | |
269 | uschar *s = expanded; | |
270 | while (isdigit(*s)) | |
271 | max_for_this_host = max_for_this_host * 10 + *s++ - '0'; | |
272 | if (*s != 0) | |
273 | log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host " | |
acec9514 | 274 | "for %s contains non-digit: %s", whofrom->s, expanded); |
059ec3d9 PH |
275 | } |
276 | } | |
277 | ||
278 | /* If we have fewer connections than max_for_this_host, we can skip the tedious | |
279 | per host_address checks. Note that at this stage smtp_accept_count contains the | |
280 | count of *other* connections, not including this one. */ | |
281 | ||
282 | if ((max_for_this_host > 0) && | |
283 | (smtp_accept_count >= max_for_this_host)) | |
284 | { | |
285 | int i; | |
286 | int host_accept_count = 0; | |
287 | int other_host_count = 0; /* keep a count of non matches to optimise */ | |
288 | ||
289 | for (i = 0; i < smtp_accept_max; ++i) | |
8cfd0f7b | 290 | if (smtp_slots[i].host_address) |
059ec3d9 PH |
291 | { |
292 | if (Ustrcmp(sender_host_address, smtp_slots[i].host_address) == 0) | |
293 | host_accept_count++; | |
294 | else | |
295 | other_host_count++; | |
296 | ||
297 | /* Testing all these strings is expensive - see if we can drop out | |
298 | early, either by hitting the target, or finding there are not enough | |
299 | connections left to make the target. */ | |
300 | ||
301 | if ((host_accept_count >= max_for_this_host) || | |
302 | ((smtp_accept_count - other_host_count) < max_for_this_host)) | |
303 | break; | |
304 | } | |
059ec3d9 PH |
305 | |
306 | if (host_accept_count >= max_for_this_host) | |
307 | { | |
308 | DEBUG(D_any) debug_printf("rejecting SMTP connection: too many from this " | |
309 | "IP address: count=%d max=%d\n", | |
310 | host_accept_count, max_for_this_host); | |
311 | smtp_printf("421 Too many concurrent SMTP connections " | |
925ac8e4 | 312 | "from this IP address; please try again later.\r\n", FALSE); |
059ec3d9 PH |
313 | log_write(L_connection_reject, |
314 | LOG_MAIN, "Connection from %s refused: too many connections " | |
acec9514 | 315 | "from that IP address", whofrom->s); |
059ec3d9 PH |
316 | goto ERROR_RETURN; |
317 | } | |
318 | } | |
319 | ||
320 | /* OK, the connection count checks have been passed. Before we can fork the | |
321 | accepting process, we must first log the connection if requested. This logging | |
322 | used to happen in the subprocess, but doing that means that the value of | |
323 | smtp_accept_count can be out of step by the time it is logged. So we have to do | |
324 | the logging here and accept the performance cost. Note that smtp_accept_count | |
325 | hasn't yet been incremented to take account of this connection. | |
326 | ||
327 | In order to minimize the cost (because this is going to happen for every | |
328 | connection), do a preliminary selector test here. This saves ploughing through | |
329 | the generalized logging code each time when the selector is false. If the | |
330 | selector is set, check whether the host is on the list for logging. If not, | |
331 | arrange to unset the selector in the subprocess. */ | |
332 | ||
6c6d6e48 | 333 | if (LOGGING(smtp_connection)) |
059ec3d9 PH |
334 | { |
335 | uschar *list = hosts_connection_nolog; | |
ce325893 | 336 | memset(sender_host_cache, 0, sizeof(sender_host_cache)); |
059ec3d9 | 337 | if (list != NULL && verify_check_host(&list) == OK) |
6c6d6e48 | 338 | save_log_selector &= ~L_smtp_connection; |
059ec3d9 PH |
339 | else |
340 | log_write(L_smtp_connection, LOG_MAIN, "SMTP connection from %s " | |
acec9514 | 341 | "(TCP/IP connection count = %d)", whofrom->s, smtp_accept_count + 1); |
059ec3d9 PH |
342 | } |
343 | ||
344 | /* Now we can fork the accepting process; do a lookup tidy, just in case any | |
345 | expansion above did a lookup. */ | |
346 | ||
347 | search_tidyup(); | |
348 | pid = fork(); | |
349 | ||
350 | /* Handle the child process */ | |
351 | ||
352 | if (pid == 0) | |
353 | { | |
354 | int i; | |
355 | int queue_only_reason = 0; | |
356 | int old_pool = store_pool; | |
8e669ac1 | 357 | int save_debug_selector = debug_selector; |
059ec3d9 | 358 | BOOL local_queue_only; |
8669f003 | 359 | BOOL session_local_queue_only; |
059ec3d9 PH |
360 | #ifdef SA_NOCLDWAIT |
361 | struct sigaction act; | |
362 | #endif | |
363 | ||
b01dd148 PH |
364 | smtp_accept_count++; /* So that it includes this process */ |
365 | ||
059ec3d9 PH |
366 | /* May have been modified for the subprocess */ |
367 | ||
6c6d6e48 | 368 | *log_selector = save_log_selector; |
059ec3d9 PH |
369 | |
370 | /* Get the local interface address into permanent store */ | |
371 | ||
372 | store_pool = POOL_PERM; | |
373 | interface_address = string_copy(interface_address); | |
374 | store_pool = old_pool; | |
375 | ||
376 | /* Check for a tls-on-connect port */ | |
377 | ||
817d9f57 | 378 | if (host_is_tls_on_connect_port(interface_port)) tls_in.on_connect = TRUE; |
059ec3d9 PH |
379 | |
380 | /* Expand smtp_active_hostname if required. We do not do this any earlier, | |
381 | because it may depend on the local interface address (indeed, that is most | |
382 | likely what it depends on.) */ | |
383 | ||
384 | smtp_active_hostname = primary_hostname; | |
ad7fc6eb | 385 | if (raw_active_hostname) |
059ec3d9 | 386 | { |
ad7fc6eb JH |
387 | uschar * nah = expand_string(raw_active_hostname); |
388 | if (!nah) | |
059ec3d9 | 389 | { |
8768d548 | 390 | if (!f.expand_string_forcedfail) |
059ec3d9 PH |
391 | { |
392 | log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand \"%s\" " | |
393 | "(smtp_active_hostname): %s", raw_active_hostname, | |
394 | expand_string_message); | |
395 | smtp_printf("421 Local configuration error; " | |
925ac8e4 | 396 | "please try again later.\r\n", FALSE); |
059ec3d9 PH |
397 | mac_smtp_fflush(); |
398 | search_tidyup(); | |
399 | _exit(EXIT_FAILURE); | |
400 | } | |
401 | } | |
ad7fc6eb | 402 | else if (*nah) smtp_active_hostname = nah; |
059ec3d9 PH |
403 | } |
404 | ||
405 | /* Initialize the queueing flags */ | |
406 | ||
407 | queue_check_only(); | |
8669f003 | 408 | session_local_queue_only = queue_only; |
059ec3d9 PH |
409 | |
410 | /* Close the listening sockets, and set the SIGCHLD handler to SIG_IGN. | |
411 | We also attempt to set things up so that children are automatically reaped, | |
412 | but just in case this isn't available, there's a paranoid waitpid() in the | |
413 | loop too (except for systems where we are sure it isn't needed). See the more | |
414 | extensive comment before the reception loop in exim.c for a fuller | |
415 | explanation of this logic. */ | |
416 | ||
f1e894f3 | 417 | for (i = 0; i < listen_socket_count; i++) (void)close(listen_sockets[i]); |
059ec3d9 | 418 | |
fa32850b DW |
419 | /* Set FD_CLOEXEC on the SMTP socket. We don't want any rogue child processes |
420 | to be able to communicate with them, under any circumstances. */ | |
421 | (void)fcntl(accept_socket, F_SETFD, | |
422 | fcntl(accept_socket, F_GETFD) | FD_CLOEXEC); | |
423 | (void)fcntl(dup_accept_socket, F_SETFD, | |
424 | fcntl(dup_accept_socket, F_GETFD) | FD_CLOEXEC); | |
425 | ||
059ec3d9 PH |
426 | #ifdef SA_NOCLDWAIT |
427 | act.sa_handler = SIG_IGN; | |
428 | sigemptyset(&(act.sa_mask)); | |
429 | act.sa_flags = SA_NOCLDWAIT; | |
430 | sigaction(SIGCHLD, &act, NULL); | |
431 | #else | |
432 | signal(SIGCHLD, SIG_IGN); | |
433 | #endif | |
434 | ||
435 | /* Attempt to get an id from the sending machine via the RFC 1413 | |
436 | protocol. We do this in the sub-process in order not to hold up the | |
437 | main process if there is any delay. Then set up the fullhost information | |
8e669ac1 PH |
438 | in case there is no HELO/EHLO. |
439 | ||
440 | If debugging is enabled only for the daemon, we must turn if off while | |
441 | finding the id, but turn it on again afterwards so that information about the | |
3d235903 | 442 | incoming connection is output. */ |
8e669ac1 | 443 | |
8768d548 | 444 | if (f.debug_daemon) debug_selector = 0; |
059ec3d9 PH |
445 | verify_get_ident(IDENT_PORT); |
446 | host_build_sender_fullhost(); | |
8e669ac1 | 447 | debug_selector = save_debug_selector; |
059ec3d9 PH |
448 | |
449 | DEBUG(D_any) | |
450 | debug_printf("Process %d is handling incoming connection from %s\n", | |
451 | (int)getpid(), sender_fullhost); | |
452 | ||
3d235903 PH |
453 | /* Now disable debugging permanently if it's required only for the daemon |
454 | process. */ | |
455 | ||
8768d548 | 456 | if (f.debug_daemon) debug_selector = 0; |
3d235903 | 457 | |
059ec3d9 | 458 | /* If there are too many child processes for immediate delivery, |
8669f003 | 459 | set the session_local_queue_only flag, which is initialized from the |
059ec3d9 | 460 | configured value and may therefore already be TRUE. Leave logging |
8669f003 PH |
461 | till later so it will have a message id attached. Note that there is no |
462 | possibility of re-calculating this per-message, because the value of | |
463 | smtp_accept_count does not change in this subprocess. */ | |
059ec3d9 | 464 | |
b01dd148 | 465 | if (smtp_accept_queue > 0 && smtp_accept_count > smtp_accept_queue) |
059ec3d9 | 466 | { |
8669f003 | 467 | session_local_queue_only = TRUE; |
059ec3d9 PH |
468 | queue_only_reason = 1; |
469 | } | |
470 | ||
471 | /* Handle the start of the SMTP session, then loop, accepting incoming | |
472 | messages from the SMTP connection. The end will come at the QUIT command, | |
473 | when smtp_setup_msg() returns 0. A break in the connection causes the | |
24796b8d PH |
474 | process to die (see accept.c). |
475 | ||
476 | NOTE: We do *not* call smtp_log_no_mail() if smtp_start_session() fails, | |
477 | because a log line has already been written for all its failure exists | |
478 | (usually "connection refused: <reason>") and writing another one is | |
479 | unnecessary clutter. */ | |
059ec3d9 PH |
480 | |
481 | if (!smtp_start_session()) | |
482 | { | |
483 | mac_smtp_fflush(); | |
484 | search_tidyup(); | |
485 | _exit(EXIT_SUCCESS); | |
486 | } | |
487 | ||
488 | for (;;) | |
489 | { | |
490 | int rc; | |
491 | message_id[0] = 0; /* Clear out any previous message_id */ | |
492 | reset_point = store_get(0); /* Save current store high water point */ | |
493 | ||
494 | DEBUG(D_any) | |
495 | debug_printf("Process %d is ready for new message\n", (int)getpid()); | |
496 | ||
497 | /* Smtp_setup_msg() returns 0 on QUIT or if the call is from an | |
498 | unacceptable host or if an ACL "drop" command was triggered, -1 on | |
499 | connection lost, and +1 on validly reaching DATA. Receive_msg() almost | |
500 | always returns TRUE when smtp_input is true; just retry if no message was | |
501 | accepted (can happen for invalid message parameters). However, it can yield | |
502 | FALSE if the connection was forcibly dropped by the DATA ACL. */ | |
503 | ||
504 | if ((rc = smtp_setup_msg()) > 0) | |
505 | { | |
506 | BOOL ok = receive_msg(FALSE); | |
507 | search_tidyup(); /* Close cached databases */ | |
508 | if (!ok) /* Connection was dropped */ | |
509 | { | |
57cc2785 | 510 | cancel_cutthrough_connection(TRUE, US"receive dropped"); |
059ec3d9 | 511 | mac_smtp_fflush(); |
b4ed4da0 | 512 | smtp_log_no_mail(); /* Log no mail if configured */ |
059ec3d9 PH |
513 | _exit(EXIT_SUCCESS); |
514 | } | |
515 | if (message_id[0] == 0) continue; /* No message was accepted */ | |
516 | } | |
517 | else | |
518 | { | |
ad7fc6eb JH |
519 | if (smtp_out) |
520 | { | |
5ddc9771 | 521 | int i, fd = fileno(smtp_in); |
ad7fc6eb JH |
522 | uschar buf[128]; |
523 | ||
524 | mac_smtp_fflush(); | |
525 | /* drain socket, for clean TCP FINs */ | |
5ddc9771 JH |
526 | if (fcntl(fd, F_SETFL, O_NONBLOCK) == 0) |
527 | for(i = 16; read(fd, buf, sizeof(buf)) > 0 && i > 0; ) i--; | |
ad7fc6eb | 528 | } |
57cc2785 | 529 | cancel_cutthrough_connection(TRUE, US"message setup dropped"); |
059ec3d9 | 530 | search_tidyup(); |
b4ed4da0 | 531 | smtp_log_no_mail(); /* Log no mail if configured */ |
60d10ce7 JH |
532 | |
533 | /*XXX should we pause briefly, hoping that the client will be the | |
534 | active TCP closer hence get the TCP_WAIT endpoint? */ | |
535 | DEBUG(D_receive) debug_printf("SMTP>>(close on process exit)\n"); | |
f5d25c2b | 536 | _exit(rc ? EXIT_FAILURE : EXIT_SUCCESS); |
059ec3d9 PH |
537 | } |
538 | ||
539 | /* Show the recipients when debugging */ | |
540 | ||
541 | DEBUG(D_receive) | |
542 | { | |
543 | int i; | |
2c0f3ea1 | 544 | if (sender_address) |
059ec3d9 | 545 | debug_printf("Sender: %s\n", sender_address); |
2c0f3ea1 | 546 | if (recipients_list) |
059ec3d9 PH |
547 | { |
548 | debug_printf("Recipients:\n"); | |
549 | for (i = 0; i < recipients_count; i++) | |
550 | debug_printf(" %s\n", recipients_list[i].address); | |
551 | } | |
552 | } | |
553 | ||
554 | /* A message has been accepted. Clean up any previous delivery processes | |
555 | that have completed and are defunct, on systems where they don't go away | |
556 | by themselves (see comments when setting SIG_IGN above). On such systems | |
557 | (if any) these delivery processes hang around after termination until | |
558 | the next message is received. */ | |
559 | ||
560 | #ifndef SIG_IGN_WORKS | |
561 | while (waitpid(-1, NULL, WNOHANG) > 0); | |
562 | #endif | |
563 | ||
564 | /* Reclaim up the store used in accepting this message */ | |
565 | ||
e04bfa34 JH |
566 | { |
567 | int r = receive_messagecount; | |
8768d548 | 568 | BOOL q = f.queue_only_policy; |
e04bfa34 | 569 | smtp_reset(reset_point); |
8768d548 | 570 | f.queue_only_policy = q; |
e04bfa34 JH |
571 | receive_messagecount = r; |
572 | } | |
059ec3d9 PH |
573 | |
574 | /* If queue_only is set or if there are too many incoming connections in | |
8669f003 PH |
575 | existence, session_local_queue_only will be TRUE. If it is not, check |
576 | whether we have received too many messages in this session for immediate | |
577 | delivery. */ | |
578 | ||
579 | if (!session_local_queue_only && | |
580 | smtp_accept_queue_per_connection > 0 && | |
581 | receive_messagecount > smtp_accept_queue_per_connection) | |
059ec3d9 | 582 | { |
8669f003 PH |
583 | session_local_queue_only = TRUE; |
584 | queue_only_reason = 2; | |
585 | } | |
586 | ||
587 | /* Initialize local_queue_only from session_local_queue_only. If it is not | |
588 | true, and queue_only_load is set, check that the load average is below it. | |
589 | If local_queue_only is set by this means, we also set if for the session if | |
590 | queue_only_load_latch is true (the default). This means that, once set, | |
591 | local_queue_only remains set for any subsequent messages on the same SMTP | |
592 | connection. This is a deliberate choice; even though the load average may | |
593 | fall, it doesn't seem right to deliver later messages on the same call when | |
594 | not delivering earlier ones. However, the are special circumstances such as | |
595 | very long-lived connections from scanning appliances where this is not the | |
596 | best strategy. In such cases, queue_only_load_latch should be set false. */ | |
597 | ||
f5d25c2b JH |
598 | if ( !(local_queue_only = session_local_queue_only) |
599 | && queue_only_load >= 0 | |
600 | && (local_queue_only = (load_average = OS_GETLOADAVG()) > queue_only_load) | |
601 | ) | |
8669f003 | 602 | { |
f5d25c2b JH |
603 | queue_only_reason = 3; |
604 | if (queue_only_load_latch) session_local_queue_only = TRUE; | |
059ec3d9 PH |
605 | } |
606 | ||
607 | /* Log the queueing here, when it will get a message id attached, but | |
608 | not if queue_only is set (case 0). */ | |
609 | ||
610 | if (local_queue_only) switch(queue_only_reason) | |
611 | { | |
f5d25c2b | 612 | case 1: log_write(L_delay_delivery, |
059ec3d9 PH |
613 | LOG_MAIN, "no immediate delivery: too many connections " |
614 | "(%d, max %d)", smtp_accept_count, smtp_accept_queue); | |
f5d25c2b | 615 | break; |
059ec3d9 | 616 | |
f5d25c2b | 617 | case 2: log_write(L_delay_delivery, |
059ec3d9 PH |
618 | LOG_MAIN, "no immediate delivery: more than %d messages " |
619 | "received in one connection", smtp_accept_queue_per_connection); | |
f5d25c2b | 620 | break; |
059ec3d9 | 621 | |
f5d25c2b | 622 | case 3: log_write(L_delay_delivery, |
059ec3d9 PH |
623 | LOG_MAIN, "no immediate delivery: load average %.2f", |
624 | (double)load_average/1000.0); | |
f5d25c2b | 625 | break; |
059ec3d9 PH |
626 | } |
627 | ||
628 | /* If a delivery attempt is required, spin off a new process to handle it. | |
629 | If we are not root, we have to re-exec exim unless deliveries are being | |
630 | done unprivileged. */ | |
631 | ||
8768d548 | 632 | else if (!f.queue_only_policy && !f.deliver_freeze) |
059ec3d9 PH |
633 | { |
634 | pid_t dpid; | |
635 | ||
636 | /* Before forking, ensure that the C output buffer is flushed. Otherwise | |
637 | anything that it in it will get duplicated, leading to duplicate copies | |
638 | of the pending output. */ | |
639 | ||
640 | mac_smtp_fflush(); | |
641 | ||
642 | if ((dpid = fork()) == 0) | |
643 | { | |
f1e894f3 PH |
644 | (void)fclose(smtp_in); |
645 | (void)fclose(smtp_out); | |
059ec3d9 PH |
646 | |
647 | /* Don't ever molest the parent's SSL connection, but do clean up | |
648 | the data structures if necessary. */ | |
649 | ||
57cc2785 | 650 | #ifdef SUPPORT_TLS |
74f1a423 | 651 | tls_close(NULL, TLS_NO_SHUTDOWN); |
57cc2785 | 652 | #endif |
059ec3d9 PH |
653 | |
654 | /* Reset SIGHUP and SIGCHLD in the child in both cases. */ | |
655 | ||
656 | signal(SIGHUP, SIG_DFL); | |
657 | signal(SIGCHLD, SIG_DFL); | |
658 | ||
659 | if (geteuid() != root_uid && !deliver_drop_privilege) | |
660 | { | |
661 | signal(SIGALRM, SIG_DFL); | |
57cc2785 | 662 | delivery_re_exec(CEE_EXEC_PANIC); |
059ec3d9 PH |
663 | /* Control does not return here. */ |
664 | } | |
665 | ||
666 | /* No need to re-exec; SIGALRM remains set to the default handler */ | |
667 | ||
57cc2785 | 668 | (void) deliver_message(message_id, FALSE, FALSE); |
059ec3d9 PH |
669 | search_tidyup(); |
670 | _exit(EXIT_SUCCESS); | |
671 | } | |
672 | ||
673 | if (dpid > 0) | |
674 | { | |
57cc2785 | 675 | release_cutthrough_connection(US"passed for delivery"); |
059ec3d9 PH |
676 | DEBUG(D_any) debug_printf("forked delivery process %d\n", (int)dpid); |
677 | } | |
678 | else | |
57cc2785 JH |
679 | { |
680 | cancel_cutthrough_connection(TRUE, US"delivery fork failed"); | |
059ec3d9 PH |
681 | log_write(0, LOG_MAIN|LOG_PANIC, "daemon: delivery process fork " |
682 | "failed: %s", strerror(errno)); | |
57cc2785 | 683 | } |
059ec3d9 PH |
684 | } |
685 | } | |
686 | } | |
687 | ||
688 | ||
689 | /* Carrying on in the parent daemon process... Can't do much if the fork | |
690 | failed. Otherwise, keep count of the number of accepting processes and | |
691 | remember the pid for ticking off when the child completes. */ | |
692 | ||
693 | if (pid < 0) | |
059ec3d9 | 694 | never_error(US"daemon: accept process fork failed", US"Fork failed", errno); |
059ec3d9 PH |
695 | else |
696 | { | |
697 | int i; | |
698 | for (i = 0; i < smtp_accept_max; ++i) | |
059ec3d9 PH |
699 | if (smtp_slots[i].pid <= 0) |
700 | { | |
701 | smtp_slots[i].pid = pid; | |
702 | if (smtp_accept_max_per_host != NULL) | |
703 | smtp_slots[i].host_address = string_copy_malloc(sender_host_address); | |
704 | smtp_accept_count++; | |
705 | break; | |
706 | } | |
059ec3d9 PH |
707 | DEBUG(D_any) debug_printf("%d SMTP accept process%s running\n", |
708 | smtp_accept_count, (smtp_accept_count == 1)? "" : "es"); | |
709 | } | |
710 | ||
711 | /* Get here via goto in error cases */ | |
712 | ||
713 | ERROR_RETURN: | |
714 | ||
715 | /* Close the streams associated with the socket which will also close the | |
716 | socket fds in this process. We can't do anything if fclose() fails, but | |
717 | logging brings it to someone's attention. However, "connection reset by peer" | |
1f872c80 PH |
718 | isn't really a problem, so skip that one. On Solaris, a dropped connection can |
719 | manifest itself as a broken pipe, so drop that one too. If the streams don't | |
720 | exist, something went wrong while setting things up. Make sure the socket | |
721 | descriptors are closed, in order to drop the connection. */ | |
059ec3d9 | 722 | |
f5d25c2b | 723 | if (smtp_out) |
059ec3d9 | 724 | { |
1f872c80 | 725 | if (fclose(smtp_out) != 0 && errno != ECONNRESET && errno != EPIPE) |
059ec3d9 PH |
726 | log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_out) failed: %s", |
727 | strerror(errno)); | |
728 | smtp_out = NULL; | |
729 | } | |
f1e894f3 | 730 | else (void)close(accept_socket); |
059ec3d9 | 731 | |
f5d25c2b | 732 | if (smtp_in) |
059ec3d9 | 733 | { |
1f872c80 | 734 | if (fclose(smtp_in) != 0 && errno != ECONNRESET && errno != EPIPE) |
059ec3d9 PH |
735 | log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fclose(smtp_in) failed: %s", |
736 | strerror(errno)); | |
737 | smtp_in = NULL; | |
738 | } | |
f1e894f3 | 739 | else (void)close(dup_accept_socket); |
059ec3d9 PH |
740 | |
741 | /* Release any store used in this process, including the store used for holding | |
742 | the incoming host address and an expanded active_hostname. */ | |
743 | ||
c8899c20 | 744 | log_close_all(); |
90341c71 JH |
745 | interface_address = |
746 | sender_host_address = NULL; | |
059ec3d9 PH |
747 | store_reset(reset_point); |
748 | sender_host_address = NULL; | |
749 | } | |
750 | ||
751 | ||
752 | ||
753 | ||
754 | /************************************************* | |
755 | * Check wildcard listen special cases * | |
756 | *************************************************/ | |
757 | ||
758 | /* This function is used when binding and listening on lists of addresses and | |
759 | ports. It tests for special cases of wildcard listening, when IPv4 and IPv6 | |
760 | sockets may interact in different ways in different operating systems. It is | |
761 | passed an error number, the list of listening addresses, and the current | |
762 | address. Two checks are available: for a previous wildcard IPv6 address, or for | |
763 | a following wildcard IPv4 address, in both cases on the same port. | |
764 | ||
765 | In practice, pairs of wildcard addresses should be adjacent in the address list | |
766 | because they are sorted that way below. | |
767 | ||
768 | Arguments: | |
769 | eno the error number | |
770 | addresses the list of addresses | |
771 | ipa the current IP address | |
772 | back if TRUE, check for previous wildcard IPv6 address | |
773 | if FALSE, check for a following wildcard IPv4 address | |
774 | ||
775 | Returns: TRUE or FALSE | |
776 | */ | |
777 | ||
778 | static BOOL | |
779 | check_special_case(int eno, ip_address_item *addresses, ip_address_item *ipa, | |
780 | BOOL back) | |
781 | { | |
782 | ip_address_item *ipa2; | |
783 | ||
784 | /* For the "back" case, if the failure was "address in use" for a wildcard IPv4 | |
785 | address, seek a previous IPv6 wildcard address on the same port. As it is | |
786 | previous, it must have been successfully bound and be listening. Flag it as a | |
787 | "6 including 4" listener. */ | |
788 | ||
789 | if (back) | |
790 | { | |
791 | if (eno != EADDRINUSE || ipa->address[0] != 0) return FALSE; | |
792 | for (ipa2 = addresses; ipa2 != ipa; ipa2 = ipa2->next) | |
793 | { | |
794 | if (ipa2->address[1] == 0 && ipa2->port == ipa->port) | |
795 | { | |
796 | ipa2->v6_include_v4 = TRUE; | |
797 | return TRUE; | |
798 | } | |
799 | } | |
800 | } | |
801 | ||
802 | /* For the "forward" case, if the current address is a wildcard IPv6 address, | |
803 | we seek a following wildcard IPv4 address on the same port. */ | |
804 | ||
805 | else | |
806 | { | |
807 | if (ipa->address[0] != ':' || ipa->address[1] != 0) return FALSE; | |
808 | for (ipa2 = ipa->next; ipa2 != NULL; ipa2 = ipa2->next) | |
809 | if (ipa2->address[0] == 0 && ipa->port == ipa2->port) return TRUE; | |
810 | } | |
811 | ||
812 | return FALSE; | |
813 | } | |
814 | ||
815 | ||
816 | ||
817 | ||
bb6e88ff PH |
818 | /************************************************* |
819 | * Handle terminating subprocesses * | |
820 | *************************************************/ | |
821 | ||
822 | /* Handle the termination of child processes. Theoretically, this need be done | |
823 | only when sigchld_seen is TRUE, but rumour has it that some systems lose | |
824 | SIGCHLD signals at busy times, so to be on the safe side, this function is | |
825 | called each time round. It shouldn't be too expensive. | |
826 | ||
827 | Arguments: none | |
828 | Returns: nothing | |
829 | */ | |
830 | ||
831 | static void | |
832 | handle_ending_processes(void) | |
833 | { | |
834 | int status; | |
835 | pid_t pid; | |
836 | ||
837 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) | |
838 | { | |
839 | int i; | |
7be682ca PP |
840 | DEBUG(D_any) |
841 | { | |
842 | debug_printf("child %d ended: status=0x%x\n", (int)pid, status); | |
843 | #ifdef WCOREDUMP | |
844 | if (WIFEXITED(status)) | |
845 | debug_printf(" normal exit, %d\n", WEXITSTATUS(status)); | |
846 | else if (WIFSIGNALED(status)) | |
847 | debug_printf(" signal exit, signal %d%s\n", WTERMSIG(status), | |
848 | WCOREDUMP(status) ? " (core dumped)" : ""); | |
849 | #endif | |
850 | } | |
bb6e88ff | 851 | |
8e669ac1 | 852 | /* If it's a listening daemon for which we are keeping track of individual |
bb6e88ff PH |
853 | subprocesses, deal with an accepting process that has terminated. */ |
854 | ||
8cfd0f7b | 855 | if (smtp_slots) |
bb6e88ff PH |
856 | { |
857 | for (i = 0; i < smtp_accept_max; i++) | |
bb6e88ff PH |
858 | if (smtp_slots[i].pid == pid) |
859 | { | |
8cfd0f7b | 860 | if (smtp_slots[i].host_address) |
bb6e88ff PH |
861 | store_free(smtp_slots[i].host_address); |
862 | smtp_slots[i] = empty_smtp_slot; | |
863 | if (--smtp_accept_count < 0) smtp_accept_count = 0; | |
864 | DEBUG(D_any) debug_printf("%d SMTP accept process%s now running\n", | |
865 | smtp_accept_count, (smtp_accept_count == 1)? "" : "es"); | |
866 | break; | |
867 | } | |
bb6e88ff PH |
868 | if (i < smtp_accept_max) continue; /* Found an accepting process */ |
869 | } | |
870 | ||
871 | /* If it wasn't an accepting process, see if it was a queue-runner | |
872 | process that we are tracking. */ | |
873 | ||
0cd5fd23 | 874 | if (queue_pid_slots) |
bb6e88ff | 875 | { |
4dc2379a | 876 | int max = atoi(CS expand_string(queue_run_max)); |
0cd5fd23 | 877 | for (i = 0; i < max; i++) |
bb6e88ff PH |
878 | if (queue_pid_slots[i] == pid) |
879 | { | |
880 | queue_pid_slots[i] = 0; | |
881 | if (--queue_run_count < 0) queue_run_count = 0; | |
882 | DEBUG(D_any) debug_printf("%d queue-runner process%s now running\n", | |
883 | queue_run_count, (queue_run_count == 1)? "" : "es"); | |
884 | break; | |
885 | } | |
bb6e88ff PH |
886 | } |
887 | } | |
888 | } | |
889 | ||
059ec3d9 PH |
890 | |
891 | ||
892 | /************************************************* | |
893 | * Exim Daemon Mainline * | |
894 | *************************************************/ | |
895 | ||
896 | /* The daemon can do two jobs, either of which is optional: | |
897 | ||
898 | (1) Listens for incoming SMTP calls and spawns off a sub-process to handle | |
899 | each one. This is requested by the -bd option, with -oX specifying the SMTP | |
900 | port on which to listen (for testing). | |
901 | ||
902 | (2) Spawns a queue-running process every so often. This is controlled by the | |
903 | -q option with a an interval time. (If no time is given, a single queue run | |
904 | is done from the main function, and control doesn't get here.) | |
905 | ||
906 | Root privilege is required in order to attach to port 25. Some systems require | |
907 | it when calling socket() rather than bind(). To cope with all cases, we run as | |
908 | root for both socket() and bind(). Some systems also require root in order to | |
909 | write to the pid file directory. This function must therefore be called as root | |
910 | if it is to work properly in all circumstances. Once the socket is bound and | |
911 | the pid file written, root privilege is given up if there is an exim uid. | |
912 | ||
913 | There are no arguments to this function, and it never returns. */ | |
914 | ||
915 | void | |
916 | daemon_go(void) | |
917 | { | |
ebeaf996 | 918 | struct passwd *pw; |
059ec3d9 PH |
919 | int *listen_sockets = NULL; |
920 | int listen_socket_count = 0; | |
921 | ip_address_item *addresses = NULL; | |
9ee44efb | 922 | time_t last_connection_time = (time_t)0; |
4dc2379a | 923 | int local_queue_run_max = atoi(CS expand_string(queue_run_max)); |
059ec3d9 PH |
924 | |
925 | /* If any debugging options are set, turn on the D_pid bit so that all | |
926 | debugging lines get the pid added. */ | |
927 | ||
928 | DEBUG(D_any|D_v) debug_selector |= D_pid; | |
929 | ||
8768d548 | 930 | if (f.inetd_wait_mode) |
9ee44efb | 931 | { |
9ee44efb | 932 | listen_socket_count = 1; |
96f5fe4c | 933 | listen_sockets = store_get(sizeof(int)); |
9ee44efb PP |
934 | (void) close(3); |
935 | if (dup2(0, 3) == -1) | |
9ee44efb PP |
936 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, |
937 | "failed to dup inetd socket safely away: %s", strerror(errno)); | |
d4ff61d1 | 938 | |
9ee44efb PP |
939 | listen_sockets[0] = 3; |
940 | (void) close(0); | |
941 | (void) close(1); | |
942 | (void) close(2); | |
943 | exim_nullstd(); | |
944 | ||
945 | if (debug_file == stderr) | |
946 | { | |
947 | /* need a call to log_write before call to open debug_file, so that | |
948 | log.c:file_path has been initialised. This is unfortunate. */ | |
949 | log_write(0, LOG_MAIN, "debugging Exim in inetd wait mode starting"); | |
950 | ||
951 | fclose(debug_file); | |
952 | debug_file = NULL; | |
953 | exim_nullstd(); /* re-open fd2 after we just closed it again */ | |
954 | debug_logging_activate(US"-wait", NULL); | |
955 | } | |
956 | ||
957 | DEBUG(D_any) debug_printf("running in inetd wait mode\n"); | |
958 | ||
959 | /* As per below, when creating sockets ourselves, we handle tcp_nodelay for | |
960 | our own buffering; we assume though that inetd set the socket REUSEADDR. */ | |
961 | ||
d4ff61d1 JH |
962 | if (tcp_nodelay) |
963 | if (setsockopt(3, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on))) | |
964 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to set socket NODELAY: %s", | |
965 | strerror(errno)); | |
9ee44efb PP |
966 | } |
967 | ||
968 | ||
8768d548 | 969 | if (f.inetd_wait_mode || f.daemon_listen) |
9ee44efb PP |
970 | { |
971 | /* If any option requiring a load average to be available during the | |
972 | reception of a message is set, call os_getloadavg() while we are root | |
973 | for those OS for which this is necessary the first time it is called (in | |
974 | order to perform an "open" on the kernel memory file). */ | |
975 | ||
976 | #ifdef LOAD_AVG_NEEDS_ROOT | |
977 | if (queue_only_load >= 0 || smtp_load_reserve >= 0 || | |
978 | (deliver_queue_load_max >= 0 && deliver_drop_privilege)) | |
979 | (void)os_getloadavg(); | |
980 | #endif | |
981 | } | |
982 | ||
059ec3d9 PH |
983 | |
984 | /* Do the preparation for setting up a listener on one or more interfaces, and | |
985 | possible on various ports. This is controlled by the combination of | |
986 | local_interfaces (which can set IP addresses and ports) and daemon_smtp_port | |
987 | (which is a list of default ports to use for those items in local_interfaces | |
988 | that do not specify a port). The -oX command line option can be used to | |
989 | override one or both of these options. | |
990 | ||
991 | If local_interfaces is not set, the default is to listen on all interfaces. | |
992 | When it is set, it can include "all IPvx interfaces" as an item. This is useful | |
993 | when different ports are in use. | |
994 | ||
995 | It turns out that listening on all interfaces is messy in an IPv6 world, | |
996 | because several different implementation approaches have been taken. This code | |
997 | is now supposed to work with all of them. The point of difference is whether an | |
998 | IPv6 socket that is listening on all interfaces will receive incoming IPv4 | |
999 | calls or not. We also have to cope with the case when IPv6 libraries exist, but | |
1000 | there is no IPv6 support in the kernel. | |
1001 | ||
1002 | . On Solaris, an IPv6 socket will accept IPv4 calls, and give them as mapped | |
1003 | addresses. However, if an IPv4 socket is also listening on all interfaces, | |
1004 | calls are directed to the appropriate socket. | |
1005 | ||
1006 | . On (some versions of) Linux, an IPv6 socket will accept IPv4 calls, and | |
1007 | give them as mapped addresses, but an attempt also to listen on an IPv4 | |
1008 | socket on all interfaces causes an error. | |
1009 | ||
1010 | . On OpenBSD, an IPv6 socket will not accept IPv4 calls. You have to set up | |
1011 | two sockets if you want to accept both kinds of call. | |
1012 | ||
1013 | . FreeBSD is like OpenBSD, but it has the IPV6_V6ONLY socket option, which | |
1014 | can be turned off, to make it behave like the versions of Linux described | |
1015 | above. | |
1016 | ||
1017 | . I heard a report that the USAGI IPv6 stack for Linux has implemented | |
1018 | IPV6_V6ONLY. | |
1019 | ||
1020 | So, what we do when IPv6 is supported is as follows: | |
1021 | ||
1022 | (1) After it is set up, the list of interfaces is scanned for wildcard | |
1023 | addresses. If an IPv6 and an IPv4 wildcard are both found for the same | |
1024 | port, the list is re-arranged so that they are together, with the IPv6 | |
1025 | wildcard first. | |
1026 | ||
1027 | (2) If the creation of a wildcard IPv6 socket fails, we just log the error and | |
1028 | carry on if an IPv4 wildcard socket for the same port follows later in the | |
1029 | list. This allows Exim to carry on in the case when the kernel has no IPv6 | |
1030 | support. | |
1031 | ||
1032 | (3) Having created an IPv6 wildcard socket, we try to set IPV6_V6ONLY if that | |
1033 | option is defined. However, if setting fails, carry on regardless (but log | |
1034 | the incident). | |
1035 | ||
1036 | (4) If binding or listening on an IPv6 wildcard socket fails, it is a serious | |
1037 | error. | |
1038 | ||
1039 | (5) If binding or listening on an IPv4 wildcard socket fails with the error | |
1040 | EADDRINUSE, and a previous interface was an IPv6 wildcard for the same | |
1041 | port (which must have succeeded or we wouldn't have got this far), we | |
1042 | assume we are in the situation where just a single socket is permitted, | |
1043 | and ignore the error. | |
1044 | ||
1045 | Phew! | |
1046 | ||
1047 | The preparation code decodes options and sets up the relevant data. We do this | |
1048 | first, so that we can return non-zero if there are any syntax errors, and also | |
1049 | write to stderr. */ | |
1050 | ||
8768d548 | 1051 | if (f.daemon_listen && !f.inetd_wait_mode) |
059ec3d9 PH |
1052 | { |
1053 | int *default_smtp_port; | |
1054 | int sep; | |
1055 | int pct = 0; | |
1056 | uschar *s; | |
55414b25 | 1057 | const uschar * list; |
059ec3d9 PH |
1058 | uschar *local_iface_source = US"local_interfaces"; |
1059 | ip_address_item *ipa; | |
1060 | ip_address_item **pipa; | |
1061 | ||
059ec3d9 PH |
1062 | /* If -oX was used, disable the writing of a pid file unless -oP was |
1063 | explicitly used to force it. Then scan the string given to -oX. Any items | |
1064 | that contain neither a dot nor a colon are used to override daemon_smtp_port. | |
1065 | Any other items are used to override local_interfaces. */ | |
1066 | ||
acec9514 | 1067 | if (override_local_interfaces) |
059ec3d9 | 1068 | { |
acec9514 JH |
1069 | gstring * new_smtp_port = NULL; |
1070 | gstring * new_local_interfaces = NULL; | |
059ec3d9 PH |
1071 | |
1072 | if (override_pid_file_path == NULL) write_pid = FALSE; | |
1073 | ||
1074 | list = override_local_interfaces; | |
1075 | sep = 0; | |
55414b25 | 1076 | while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size))) |
059ec3d9 PH |
1077 | { |
1078 | uschar joinstr[4]; | |
acec9514 | 1079 | gstring ** gp; |
059ec3d9 PH |
1080 | |
1081 | if (Ustrpbrk(s, ".:") == NULL) | |
acec9514 | 1082 | gp = &new_smtp_port; |
059ec3d9 | 1083 | else |
acec9514 | 1084 | gp = &new_local_interfaces; |
059ec3d9 | 1085 | |
acec9514 | 1086 | if (!*gp) |
059ec3d9 PH |
1087 | { |
1088 | joinstr[0] = sep; | |
1089 | joinstr[1] = ' '; | |
acec9514 | 1090 | *gp = string_catn(*gp, US"<", 1); |
059ec3d9 PH |
1091 | } |
1092 | ||
acec9514 JH |
1093 | *gp = string_catn(*gp, joinstr, 2); |
1094 | *gp = string_cat (*gp, s); | |
059ec3d9 PH |
1095 | } |
1096 | ||
acec9514 | 1097 | if (new_smtp_port) |
059ec3d9 | 1098 | { |
acec9514 | 1099 | daemon_smtp_port = string_from_gstring(new_smtp_port); |
059ec3d9 PH |
1100 | DEBUG(D_any) debug_printf("daemon_smtp_port overridden by -oX:\n %s\n", |
1101 | daemon_smtp_port); | |
1102 | } | |
1103 | ||
acec9514 | 1104 | if (new_local_interfaces) |
059ec3d9 | 1105 | { |
acec9514 | 1106 | local_interfaces = string_from_gstring(new_local_interfaces); |
059ec3d9 PH |
1107 | local_iface_source = US"-oX data"; |
1108 | DEBUG(D_any) debug_printf("local_interfaces overridden by -oX:\n %s\n", | |
1109 | local_interfaces); | |
1110 | } | |
1111 | } | |
1112 | ||
1113 | /* Create a list of default SMTP ports, to be used if local_interfaces | |
4c04137d | 1114 | contains entries without explicit ports. First count the number of ports, then |
059ec3d9 PH |
1115 | build a translated list in a vector. */ |
1116 | ||
1117 | list = daemon_smtp_port; | |
1118 | sep = 0; | |
55414b25 | 1119 | while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size))) |
059ec3d9 PH |
1120 | pct++; |
1121 | default_smtp_port = store_get((pct+1) * sizeof(int)); | |
1122 | list = daemon_smtp_port; | |
1123 | sep = 0; | |
1124 | for (pct = 0; | |
55414b25 | 1125 | (s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)); |
059ec3d9 PH |
1126 | pct++) |
1127 | { | |
1128 | if (isdigit(*s)) | |
1129 | { | |
1130 | uschar *end; | |
1131 | default_smtp_port[pct] = Ustrtol(s, &end, 0); | |
1132 | if (end != s + Ustrlen(s)) | |
1133 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "invalid SMTP port: %s", s); | |
1134 | } | |
1135 | else | |
1136 | { | |
1137 | struct servent *smtp_service = getservbyname(CS s, "tcp"); | |
071c51f7 | 1138 | if (!smtp_service) |
059ec3d9 PH |
1139 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s); |
1140 | default_smtp_port[pct] = ntohs(smtp_service->s_port); | |
1141 | } | |
1142 | } | |
1143 | default_smtp_port[pct] = 0; | |
1144 | ||
071c51f7 JH |
1145 | /* Check the list of TLS-on-connect ports and do name lookups if needed */ |
1146 | ||
1147 | list = tls_in.on_connect_ports; | |
1148 | sep = 0; | |
1149 | while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size))) | |
1150 | if (!isdigit(*s)) | |
1151 | { | |
acec9514 | 1152 | gstring * g = NULL; |
4226691b | 1153 | |
071c51f7 JH |
1154 | list = tls_in.on_connect_ports; |
1155 | tls_in.on_connect_ports = NULL; | |
1156 | sep = 0; | |
1157 | while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size))) | |
1158 | { | |
1159 | if (!isdigit(*s)) | |
1160 | { | |
4226691b | 1161 | struct servent * smtp_service = getservbyname(CS s, "tcp"); |
071c51f7 JH |
1162 | if (!smtp_service) |
1163 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG, "TCP port \"%s\" not found", s); | |
4226691b | 1164 | s = string_sprintf("%d", (int)ntohs(smtp_service->s_port)); |
071c51f7 | 1165 | } |
acec9514 | 1166 | g = string_append_listele(g, ':', s); |
071c51f7 | 1167 | } |
acec9514 JH |
1168 | if (g) |
1169 | tls_in.on_connect_ports = g->s; | |
071c51f7 JH |
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 | ||
b891534f | 1188 | for (ipa = addresses; ipa; ipa = ipa->next) |
059ec3d9 PH |
1189 | { |
1190 | int i; | |
1191 | ||
b891534f JH |
1192 | if (Ustrcmp(ipa->address, "0.0.0.0") == 0) |
1193 | ipa->address[0] = 0; | |
059ec3d9 PH |
1194 | else if (Ustrcmp(ipa->address, "::0") == 0) |
1195 | { | |
1196 | ipa->address[0] = ':'; | |
1197 | ipa->address[1] = 0; | |
1198 | } | |
1199 | ||
1200 | if (ipa->port > 0) continue; | |
1201 | ||
1202 | if (daemon_smtp_port[0] <= 0) | |
1203 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "no port specified for interface " | |
1204 | "%s and daemon_smtp_port is unset; cannot start daemon", | |
b891534f JH |
1205 | ipa->address[0] == 0 ? US"\"all IPv4\"" : |
1206 | ipa->address[1] == 0 ? US"\"all IPv6\"" : ipa->address); | |
1207 | ||
059ec3d9 PH |
1208 | ipa->port = default_smtp_port[0]; |
1209 | for (i = 1; default_smtp_port[i] > 0; i++) | |
1210 | { | |
1211 | ip_address_item *new = store_get(sizeof(ip_address_item)); | |
b891534f | 1212 | |
059ec3d9 PH |
1213 | memcpy(new->address, ipa->address, Ustrlen(ipa->address) + 1); |
1214 | new->port = default_smtp_port[i]; | |
1215 | new->next = ipa->next; | |
1216 | ipa->next = new; | |
1217 | ipa = new; | |
1218 | } | |
1219 | } | |
1220 | ||
1221 | /* Scan the list of addresses for wildcards. If we find an IPv4 and an IPv6 | |
1222 | wildcard for the same port, ensure that (a) they are together and (b) the | |
1223 | IPv6 address comes first. This makes handling the messy features easier, and | |
1224 | also simplifies the construction of the "daemon started" log line. */ | |
1225 | ||
1226 | pipa = &addresses; | |
b891534f | 1227 | for (ipa = addresses; ipa; pipa = &ipa->next, ipa = ipa->next) |
059ec3d9 PH |
1228 | { |
1229 | ip_address_item *ipa2; | |
1230 | ||
1231 | /* Handle an IPv4 wildcard */ | |
1232 | ||
1233 | if (ipa->address[0] == 0) | |
b891534f | 1234 | for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next) |
059ec3d9 PH |
1235 | { |
1236 | ip_address_item *ipa3 = ipa2->next; | |
1237 | if (ipa3->address[0] == ':' && | |
1238 | ipa3->address[1] == 0 && | |
1239 | ipa3->port == ipa->port) | |
1240 | { | |
1241 | ipa2->next = ipa3->next; | |
1242 | ipa3->next = ipa; | |
1243 | *pipa = ipa3; | |
1244 | break; | |
1245 | } | |
1246 | } | |
059ec3d9 PH |
1247 | |
1248 | /* Handle an IPv6 wildcard. */ | |
1249 | ||
1250 | else if (ipa->address[0] == ':' && ipa->address[1] == 0) | |
b891534f | 1251 | for (ipa2 = ipa; ipa2->next; ipa2 = ipa2->next) |
059ec3d9 PH |
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 | } | |
059ec3d9 PH |
1263 | } |
1264 | ||
1265 | /* Get a vector to remember all the sockets in */ | |
1266 | ||
b891534f | 1267 | for (ipa = addresses; ipa; ipa = ipa->next) |
059ec3d9 | 1268 | listen_socket_count++; |
96f5fe4c | 1269 | listen_sockets = store_get(sizeof(int) * listen_socket_count); |
059ec3d9 | 1270 | |
9ee44efb PP |
1271 | } /* daemon_listen but not inetd_wait_mode */ |
1272 | ||
8768d548 | 1273 | if (f.daemon_listen) |
9ee44efb PP |
1274 | { |
1275 | ||
059ec3d9 PH |
1276 | /* Do a sanity check on the max connects value just to save us from getting |
1277 | a huge amount of store. */ | |
1278 | ||
1279 | if (smtp_accept_max > 4095) smtp_accept_max = 4096; | |
1280 | ||
1281 | /* There's no point setting smtp_accept_queue unless it is less than the max | |
1282 | connects limit. The configuration reader ensures that the max is set if the | |
1283 | queue-only option is set. */ | |
1284 | ||
1285 | if (smtp_accept_queue > smtp_accept_max) smtp_accept_queue = 0; | |
1286 | ||
1287 | /* Get somewhere to keep the list of SMTP accepting pids if we are keeping | |
1288 | track of them for total number and queue/host limits. */ | |
1289 | ||
1290 | if (smtp_accept_max > 0) | |
1291 | { | |
1292 | int i; | |
1293 | smtp_slots = store_get(smtp_accept_max * sizeof(smtp_slot)); | |
1294 | for (i = 0; i < smtp_accept_max; i++) smtp_slots[i] = empty_smtp_slot; | |
1295 | } | |
1296 | } | |
1297 | ||
76a2d7ba PH |
1298 | /* The variable background_daemon is always false when debugging, but |
1299 | can also be forced false in order to keep a non-debugging daemon in the | |
1300 | foreground. If background_daemon is true, close all open file descriptors that | |
9ee44efb PP |
1301 | we know about, but then re-open stdin, stdout, and stderr to /dev/null. Also |
1302 | do this for inetd_wait mode. | |
76a2d7ba PH |
1303 | |
1304 | This is protection against any called functions (in libraries, or in | |
1305 | Perl, or whatever) that think they can write to stderr (or stdout). Before this | |
1306 | was added, it was quite likely that an SMTP connection would use one of these | |
1307 | file descriptors, in which case writing random stuff to it caused chaos. | |
1308 | ||
1309 | Then disconnect from the controlling terminal, Most modern Unixes seem to have | |
1310 | setsid() for getting rid of the controlling terminal. For any OS that doesn't, | |
1311 | setsid() can be #defined as a no-op, or as something else. */ | |
059ec3d9 | 1312 | |
8768d548 | 1313 | if (f.background_daemon || f.inetd_wait_mode) |
059ec3d9 | 1314 | { |
76a2d7ba PH |
1315 | log_close_all(); /* Just in case anything was logged earlier */ |
1316 | search_tidyup(); /* Just in case any were used in reading the config. */ | |
f1e894f3 PH |
1317 | (void)close(0); /* Get rid of stdin/stdout/stderr */ |
1318 | (void)close(1); | |
1319 | (void)close(2); | |
8e669ac1 | 1320 | exim_nullstd(); /* Connect stdin/stdout/stderr to /dev/null */ |
059ec3d9 | 1321 | log_stderr = NULL; /* So no attempt to copy paniclog output */ |
9ee44efb | 1322 | } |
059ec3d9 | 1323 | |
8768d548 | 1324 | if (f.background_daemon) |
9ee44efb | 1325 | { |
059ec3d9 | 1326 | /* If the parent process of this one has pid == 1, we are re-initializing the |
8e669ac1 | 1327 | daemon as the result of a SIGHUP. In this case, there is no need to do |
76a2d7ba PH |
1328 | anything, because the controlling terminal has long gone. Otherwise, fork, in |
1329 | case current process is a process group leader (see 'man setsid' for an | |
1330 | explanation) before calling setsid(). */ | |
059ec3d9 PH |
1331 | |
1332 | if (getppid() != 1) | |
1333 | { | |
1334 | pid_t pid = fork(); | |
1335 | if (pid < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, | |
1336 | "fork() failed when starting daemon: %s", strerror(errno)); | |
1337 | if (pid > 0) exit(EXIT_SUCCESS); /* in parent process, just exit */ | |
1338 | (void)setsid(); /* release controlling terminal */ | |
1339 | } | |
1340 | } | |
1341 | ||
1342 | /* We are now in the disconnected, daemon process (unless debugging). Set up | |
1343 | the listening sockets if required. */ | |
1344 | ||
8768d548 | 1345 | if (f.daemon_listen && !f.inetd_wait_mode) |
059ec3d9 PH |
1346 | { |
1347 | int sk; | |
059ec3d9 PH |
1348 | ip_address_item *ipa; |
1349 | ||
1350 | /* For each IP address, create a socket, bind it to the appropriate port, and | |
1351 | start listening. See comments above about IPv6 sockets that may or may not | |
1352 | accept IPv4 calls when listening on all interfaces. We also have to cope with | |
1353 | the case of a system with IPv6 libraries, but no IPv6 support in the kernel. | |
1354 | listening, provided a wildcard IPv4 socket for the same port follows. */ | |
1355 | ||
1356 | for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++) | |
1357 | { | |
1358 | BOOL wildcard; | |
1359 | ip_address_item *ipa2; | |
059ec3d9 PH |
1360 | int af; |
1361 | ||
1362 | if (Ustrchr(ipa->address, ':') != NULL) | |
1363 | { | |
1364 | af = AF_INET6; | |
1365 | wildcard = ipa->address[1] == 0; | |
1366 | } | |
1367 | else | |
1368 | { | |
1369 | af = AF_INET; | |
1370 | wildcard = ipa->address[0] == 0; | |
1371 | } | |
1372 | ||
96f5fe4c | 1373 | if ((listen_sockets[sk] = ip_socket(SOCK_STREAM, af)) < 0) |
059ec3d9 PH |
1374 | { |
1375 | if (check_special_case(0, addresses, ipa, FALSE)) | |
1376 | { | |
1377 | log_write(0, LOG_MAIN, "Failed to create IPv6 socket for wildcard " | |
1378 | "listening (%s): will use IPv4", strerror(errno)); | |
1379 | goto SKIP_SOCKET; | |
1380 | } | |
1381 | log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s", | |
1382 | (af == AF_INET6)? '6' : '4', strerror(errno)); | |
1383 | } | |
1384 | ||
1385 | /* If this is an IPv6 wildcard socket, set IPV6_V6ONLY if that option is | |
1386 | available. Just log failure (can get protocol not available, just like | |
1387 | socket creation can). */ | |
1388 | ||
b891534f | 1389 | #ifdef IPV6_V6ONLY |
059ec3d9 | 1390 | if (af == AF_INET6 && wildcard && |
5903c6ff | 1391 | setsockopt(listen_sockets[sk], IPPROTO_IPV6, IPV6_V6ONLY, CS (&on), |
059ec3d9 PH |
1392 | sizeof(on)) < 0) |
1393 | log_write(0, LOG_MAIN, "Setting IPV6_V6ONLY on daemon's IPv6 wildcard " | |
1394 | "socket failed (%s): carrying on without it", strerror(errno)); | |
b891534f | 1395 | #endif /* IPV6_V6ONLY */ |
059ec3d9 PH |
1396 | |
1397 | /* Set SO_REUSEADDR so that the daemon can be restarted while a connection | |
1398 | is being handled. Without this, a connection will prevent reuse of the | |
1399 | smtp port for listening. */ | |
1400 | ||
1401 | if (setsockopt(listen_sockets[sk], SOL_SOCKET, SO_REUSEADDR, | |
5903c6ff | 1402 | US (&on), sizeof(on)) < 0) |
059ec3d9 PH |
1403 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "setting SO_REUSEADDR on socket " |
1404 | "failed when starting daemon: %s", strerror(errno)); | |
1405 | ||
1406 | /* Set TCP_NODELAY; Exim does its own buffering. There is a switch to | |
1407 | disable this because it breaks some broken clients. */ | |
1408 | ||
1409 | if (tcp_nodelay) setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_NODELAY, | |
5903c6ff | 1410 | US (&on), sizeof(on)); |
059ec3d9 PH |
1411 | |
1412 | /* Now bind the socket to the required port; if Exim is being restarted | |
1413 | it may not always be possible to bind immediately, even with SO_REUSEADDR | |
1414 | set, so try 10 times, waiting between each try. After 10 failures, we give | |
1415 | up. In an IPv6 environment, if bind () fails with the error EADDRINUSE and | |
1416 | we are doing wildcard IPv4 listening and there was a previous IPv6 wildcard | |
1417 | address for the same port, ignore the error on the grounds that we must be | |
1418 | in a system where the IPv6 socket accepts both kinds of call. This is | |
1419 | necessary for (some release of) USAGI Linux; other IP stacks fail at the | |
1420 | listen() stage instead. */ | |
1421 | ||
6af7e591 | 1422 | #ifdef TCP_FASTOPEN |
8768d548 | 1423 | f.tcp_fastopen_ok = TRUE; |
6af7e591 | 1424 | #endif |
059ec3d9 PH |
1425 | for(;;) |
1426 | { | |
1427 | uschar *msg, *addr; | |
1428 | if (ip_bind(listen_sockets[sk], af, ipa->address, ipa->port) >= 0) break; | |
1429 | if (check_special_case(errno, addresses, ipa, TRUE)) | |
1430 | { | |
1431 | DEBUG(D_any) debug_printf("wildcard IPv4 bind() failed after IPv6 " | |
1432 | "listen() success; EADDRINUSE ignored\n"); | |
f1e894f3 | 1433 | (void)close(listen_sockets[sk]); |
059ec3d9 PH |
1434 | goto SKIP_SOCKET; |
1435 | } | |
1436 | msg = US strerror(errno); | |
b891534f JH |
1437 | addr = wildcard |
1438 | ? af == AF_INET6 | |
1439 | ? US"(any IPv6)" | |
1440 | : US"(any IPv4)" | |
1441 | : ipa->address; | |
4aee0225 | 1442 | if (daemon_startup_retries <= 0) |
059ec3d9 PH |
1443 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, |
1444 | "socket bind() to port %d for address %s failed: %s: " | |
1445 | "daemon abandoned", ipa->port, addr, msg); | |
1446 | log_write(0, LOG_MAIN, "socket bind() to port %d for address %s " | |
4aee0225 PH |
1447 | "failed: %s: waiting %s before trying again (%d more %s)", |
1448 | ipa->port, addr, msg, readconf_printtime(daemon_startup_sleep), | |
1449 | daemon_startup_retries, (daemon_startup_retries > 1)? "tries" : "try"); | |
1450 | daemon_startup_retries--; | |
1451 | sleep(daemon_startup_sleep); | |
059ec3d9 PH |
1452 | } |
1453 | ||
1454 | DEBUG(D_any) | |
059ec3d9 PH |
1455 | if (wildcard) |
1456 | debug_printf("listening on all interfaces (IPv%c) port %d\n", | |
fb05276a | 1457 | af == AF_INET6 ? '6' : '4', ipa->port); |
059ec3d9 PH |
1458 | else |
1459 | debug_printf("listening on %s port %d\n", ipa->address, ipa->port); | |
fb05276a | 1460 | |
b536a578 | 1461 | #if defined(TCP_FASTOPEN) && !defined(__APPLE__) |
590faf89 JH |
1462 | if ( f.tcp_fastopen_ok |
1463 | && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN, | |
4670e9d3 | 1464 | &smtp_connect_backlog, sizeof(smtp_connect_backlog))) |
6af7e591 | 1465 | { |
a23ff3b4 | 1466 | DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno)); |
8768d548 | 1467 | f.tcp_fastopen_ok = FALSE; |
6af7e591 | 1468 | } |
fb05276a | 1469 | #endif |
059ec3d9 PH |
1470 | |
1471 | /* Start listening on the bound socket, establishing the maximum backlog of | |
1472 | connections that is allowed. On success, continue to the next address. */ | |
1473 | ||
b536a578 JH |
1474 | if (listen(listen_sockets[sk], smtp_connect_backlog) >= 0) |
1475 | { | |
1476 | #if defined(TCP_FASTOPEN) && defined(__APPLE__) | |
1477 | if ( f.tcp_fastopen_ok | |
1478 | && setsockopt(listen_sockets[sk], IPPROTO_TCP, TCP_FASTOPEN, | |
1479 | &on, sizeof(on))) | |
1480 | { | |
1481 | DEBUG(D_any) debug_printf("setsockopt FASTOPEN: %s\n", strerror(errno)); | |
1482 | f.tcp_fastopen_ok = FALSE; | |
1483 | } | |
1484 | #endif | |
1485 | continue; | |
1486 | } | |
059ec3d9 PH |
1487 | |
1488 | /* Listening has failed. In an IPv6 environment, as for bind(), if listen() | |
1489 | fails with the error EADDRINUSE and we are doing IPv4 wildcard listening | |
1490 | and there was a previous successful IPv6 wildcard listen on the same port, | |
1491 | we want to ignore the error on the grounds that we must be in a system | |
1492 | where the IPv6 socket accepts both kinds of call. */ | |
1493 | ||
1494 | if (!check_special_case(errno, addresses, ipa, TRUE)) | |
1495 | log_write(0, LOG_PANIC_DIE, "listen() failed on interface %s: %s", | |
fb05276a JH |
1496 | wildcard |
1497 | ? af == AF_INET6 ? US"(any IPv6)" : US"(any IPv4)" : ipa->address, | |
059ec3d9 PH |
1498 | strerror(errno)); |
1499 | ||
1500 | DEBUG(D_any) debug_printf("wildcard IPv4 listen() failed after IPv6 " | |
1501 | "listen() success; EADDRINUSE ignored\n"); | |
f1e894f3 | 1502 | (void)close(listen_sockets[sk]); |
059ec3d9 PH |
1503 | |
1504 | /* Come here if there has been a problem with the socket which we | |
1505 | are going to ignore. We remove the address from the chain, and back up the | |
1506 | counts. */ | |
1507 | ||
b891534f | 1508 | SKIP_SOCKET: |
059ec3d9 PH |
1509 | sk--; /* Back up the count */ |
1510 | listen_socket_count--; /* Reduce the total */ | |
1511 | if (ipa == addresses) addresses = ipa->next; else | |
1512 | { | |
1513 | for (ipa2 = addresses; ipa2->next != ipa; ipa2 = ipa2->next); | |
1514 | ipa2->next = ipa->next; | |
1515 | ipa = ipa2; | |
1516 | } | |
1517 | } /* End of bind/listen loop for each address */ | |
1518 | } /* End of setup for listening */ | |
1519 | ||
1520 | ||
1521 | /* If we are not listening, we want to write a pid file only if -oP was | |
1522 | explicitly given. */ | |
1523 | ||
b891534f JH |
1524 | else if (!override_pid_file_path) |
1525 | write_pid = FALSE; | |
059ec3d9 PH |
1526 | |
1527 | /* Write the pid to a known file for assistance in identification, if required. | |
1528 | We do this before giving up root privilege, because on some systems it is | |
1529 | necessary to be root in order to write into the pid file directory. There's | |
1530 | nothing to stop multiple daemons running, as long as no more than one listens | |
1531 | on a given TCP/IP port on the same interface(s). However, in these | |
1532 | circumstances it gets far too complicated to mess with pid file names | |
1533 | automatically. Consequently, Exim 4 writes a pid file only | |
1534 | ||
1535 | (a) When running in the test harness, or | |
1536 | (b) When -bd is used and -oX is not used, or | |
1537 | (c) When -oP is used to supply a path. | |
1538 | ||
1539 | The variable daemon_write_pid is used to control this. */ | |
1540 | ||
8768d548 | 1541 | if (f.running_in_test_harness || write_pid) |
059ec3d9 PH |
1542 | { |
1543 | FILE *f; | |
1544 | ||
b891534f | 1545 | if (override_pid_file_path) |
059ec3d9 PH |
1546 | pid_file_path = override_pid_file_path; |
1547 | ||
1548 | if (pid_file_path[0] == 0) | |
1549 | pid_file_path = string_sprintf("%s/exim-daemon.pid", spool_directory); | |
1550 | ||
b891534f | 1551 | if ((f = modefopen(pid_file_path, "wb", 0644))) |
059ec3d9 | 1552 | { |
ff790e47 | 1553 | (void)fprintf(f, "%d\n", (int)getpid()); |
ff790e47 | 1554 | (void)fclose(f); |
059ec3d9 PH |
1555 | DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path); |
1556 | } | |
1557 | else | |
059ec3d9 PH |
1558 | DEBUG(D_any) |
1559 | debug_printf("%s\n", string_open_failed(errno, "pid file %s", | |
1560 | pid_file_path)); | |
059ec3d9 PH |
1561 | } |
1562 | ||
1563 | /* Set up the handler for SIGHUP, which causes a restart of the daemon. */ | |
1564 | ||
1565 | sighup_seen = FALSE; | |
1566 | signal(SIGHUP, sighup_handler); | |
1567 | ||
1568 | /* Give up root privilege at this point (assuming that exim_uid and exim_gid | |
1569 | are not root). The third argument controls the running of initgroups(). | |
1570 | Normally we do this, in order to set up the groups for the Exim user. However, | |
1571 | if we are not root at this time - some odd installations run that way - we | |
1572 | cannot do this. */ | |
1573 | ||
1574 | exim_setugid(exim_uid, exim_gid, geteuid()==root_uid, US"running as a daemon"); | |
1575 | ||
ebeaf996 PH |
1576 | /* Update the originator_xxx fields so that received messages as listed as |
1577 | coming from Exim, not whoever started the daemon. */ | |
1578 | ||
1579 | originator_uid = exim_uid; | |
1580 | originator_gid = exim_gid; | |
1581 | originator_login = ((pw = getpwuid(exim_uid)) != NULL)? | |
1582 | string_copy_malloc(US pw->pw_name) : US"exim"; | |
1583 | ||
059ec3d9 PH |
1584 | /* Get somewhere to keep the list of queue-runner pids if we are keeping track |
1585 | of them (and also if we are doing queue runs). */ | |
1586 | ||
0cd5fd23 | 1587 | if (queue_interval > 0 && local_queue_run_max > 0) |
059ec3d9 PH |
1588 | { |
1589 | int i; | |
0cd5fd23 JH |
1590 | queue_pid_slots = store_get(local_queue_run_max * sizeof(pid_t)); |
1591 | for (i = 0; i < local_queue_run_max; i++) queue_pid_slots[i] = 0; | |
059ec3d9 PH |
1592 | } |
1593 | ||
1594 | /* Set up the handler for termination of child processes. */ | |
1595 | ||
1596 | sigchld_seen = FALSE; | |
7d468ab8 | 1597 | os_non_restarting_signal(SIGCHLD, main_sigchld_handler); |
059ec3d9 PH |
1598 | |
1599 | /* If we are to run the queue periodically, pretend the alarm has just gone | |
1600 | off. This will cause the first queue-runner to get kicked off straight away. */ | |
1601 | ||
1602 | sigalrm_seen = (queue_interval > 0); | |
1603 | ||
1604 | /* Log the start up of a daemon - at least one of listening or queue running | |
1605 | must be set up. */ | |
1606 | ||
8768d548 | 1607 | if (f.inetd_wait_mode) |
9ee44efb PP |
1608 | { |
1609 | uschar *p = big_buffer; | |
1610 | ||
1611 | if (inetd_wait_timeout >= 0) | |
1612 | sprintf(CS p, "terminating after %d seconds", inetd_wait_timeout); | |
1613 | else | |
1614 | sprintf(CS p, "with no wait timeout"); | |
1615 | ||
1616 | log_write(0, LOG_MAIN, | |
1617 | "exim %s daemon started: pid=%d, launched with listening socket, %s", | |
1618 | version_string, getpid(), big_buffer); | |
2f21487f | 1619 | set_process_info("daemon(%s): pre-listening socket", version_string); |
9ee44efb PP |
1620 | |
1621 | /* set up the timeout logic */ | |
1622 | sigalrm_seen = 1; | |
1623 | } | |
1624 | ||
8768d548 | 1625 | else if (f.daemon_listen) |
059ec3d9 PH |
1626 | { |
1627 | int i, j; | |
1628 | int smtp_ports = 0; | |
1629 | int smtps_ports = 0; | |
e4d0fc93 | 1630 | ip_address_item * ipa, * i2; |
e37f8a84 JH |
1631 | uschar * p = big_buffer; |
1632 | uschar * qinfo = queue_interval > 0 | |
1633 | ? string_sprintf("-q%s", readconf_printtime(queue_interval)) | |
1634 | : US"no queue runs"; | |
059ec3d9 PH |
1635 | |
1636 | /* Build a list of listening addresses in big_buffer, but limit it to 10 | |
1637 | items. The style is for backwards compatibility. | |
1638 | ||
1639 | It is now possible to have some ports listening for SMTPS (the old, | |
1640 | deprecated protocol that starts TLS without using STARTTLS), and others | |
1641 | listening for standard SMTP. Keep their listings separate. */ | |
1642 | ||
1643 | for (j = 0; j < 2; j++) | |
1644 | { | |
e37f8a84 | 1645 | for (i = 0, ipa = addresses; i < 10 && ipa; i++, ipa = ipa->next) |
b891534f JH |
1646 | { |
1647 | /* First time round, look for SMTP ports; second time round, look for | |
1648 | SMTPS ports. For the first one of each, insert leading text. */ | |
1649 | ||
1650 | if (host_is_tls_on_connect_port(ipa->port) == (j > 0)) | |
1651 | { | |
1652 | if (j == 0) | |
1653 | { | |
1654 | if (smtp_ports++ == 0) | |
fc3f96af | 1655 | { |
b891534f JH |
1656 | memcpy(p, "SMTP on", 8); |
1657 | p += 7; | |
fc3f96af | 1658 | } |
b891534f JH |
1659 | } |
1660 | else | |
1661 | if (smtps_ports++ == 0) | |
1662 | p += sprintf(CS p, "%sSMTPS on", | |
1663 | smtp_ports == 0 ? "" : " and for "); | |
1664 | ||
1665 | /* Now the information about the port (and sometimes interface) */ | |
1666 | ||
1667 | if (ipa->address[0] == ':' && ipa->address[1] == 0) | |
e4d0fc93 | 1668 | { /* v6 wildcard */ |
b891534f JH |
1669 | if (ipa->next && ipa->next->address[0] == 0 && |
1670 | ipa->next->port == ipa->port) | |
1671 | { | |
1672 | p += sprintf(CS p, " port %d (IPv6 and IPv4)", ipa->port); | |
1673 | ipa = ipa->next; | |
1674 | } | |
1675 | else if (ipa->v6_include_v4) | |
1676 | p += sprintf(CS p, " port %d (IPv6 with IPv4)", ipa->port); | |
1677 | else | |
1678 | p += sprintf(CS p, " port %d (IPv6)", ipa->port); | |
1679 | } | |
e4d0fc93 | 1680 | else if (ipa->address[0] == 0) /* v4 wildcard */ |
b891534f | 1681 | p += sprintf(CS p, " port %d (IPv4)", ipa->port); |
e4d0fc93 | 1682 | else /* check for previously-seen IP */ |
b891534f | 1683 | { |
e4d0fc93 JH |
1684 | for (i2 = addresses; i2 != ipa; i2 = i2->next) |
1685 | if ( host_is_tls_on_connect_port(i2->port) == (j > 0) | |
1686 | && Ustrcmp(ipa->address, i2->address) == 0 | |
1687 | ) | |
1688 | { /* found; append port to list */ | |
1689 | if (p[-1] == '}') p--; | |
1690 | while (isdigit(*--p)) ; | |
1691 | p += 1 + sprintf(CS p+1, "%s%d,%d}", *p == ',' ? "" : "{", | |
1692 | i2->port, ipa->port); | |
1693 | break; | |
1694 | } | |
1695 | if (i2 == ipa) /* first-time IP */ | |
1696 | p += sprintf(CS p, " [%s]:%d", ipa->address, ipa->port); | |
b891534f | 1697 | } |
b891534f JH |
1698 | } |
1699 | } | |
059ec3d9 | 1700 | |
e37f8a84 | 1701 | if (ipa) |
059ec3d9 PH |
1702 | { |
1703 | memcpy(p, " ...", 5); | |
1704 | p += 4; | |
1705 | } | |
1706 | } | |
1707 | ||
1708 | log_write(0, LOG_MAIN, | |
1709 | "exim %s daemon started: pid=%d, %s, listening for %s", | |
1710 | version_string, getpid(), qinfo, big_buffer); | |
44915474 JH |
1711 | set_process_info("daemon(%s): %s, listening for %s", |
1712 | version_string, qinfo, big_buffer); | |
059ec3d9 PH |
1713 | } |
1714 | ||
1715 | else | |
1716 | { | |
44915474 JH |
1717 | uschar * s = *queue_name |
1718 | ? string_sprintf("-qG%s/%s", queue_name, readconf_printtime(queue_interval)) | |
1719 | : string_sprintf("-q%s", readconf_printtime(queue_interval)); | |
059ec3d9 | 1720 | log_write(0, LOG_MAIN, |
44915474 JH |
1721 | "exim %s daemon started: pid=%d, %s, not listening for SMTP", |
1722 | version_string, getpid(), s); | |
1723 | set_process_info("daemon(%s): %s, not listening", version_string, s); | |
059ec3d9 PH |
1724 | } |
1725 | ||
476be7e2 JH |
1726 | /* Do any work it might be useful to amortize over our children |
1727 | (eg: compile regex) */ | |
1728 | ||
476be7e2 JH |
1729 | dns_pattern_init(); |
1730 | ||
1731 | #ifdef WITH_CONTENT_SCAN | |
1732 | malware_init(); | |
1733 | #endif | |
059ec3d9 PH |
1734 | |
1735 | /* Close the log so it can be renamed and moved. In the few cases below where | |
1736 | this long-running process writes to the log (always exceptional conditions), it | |
1737 | closes the log afterwards, for the same reason. */ | |
1738 | ||
1739 | log_close_all(); | |
1740 | ||
1741 | DEBUG(D_any) debug_print_ids(US"daemon running with"); | |
1742 | ||
1743 | /* Any messages accepted via this route are going to be SMTP. */ | |
1744 | ||
1745 | smtp_input = TRUE; | |
1746 | ||
1747 | /* Enter the never-ending loop... */ | |
1748 | ||
1749 | for (;;) | |
1750 | { | |
1751 | #if HAVE_IPV6 | |
1752 | struct sockaddr_in6 accepted; | |
1753 | #else | |
1754 | struct sockaddr_in accepted; | |
1755 | #endif | |
1756 | ||
cf73943b | 1757 | EXIM_SOCKLEN_T len; |
059ec3d9 PH |
1758 | pid_t pid; |
1759 | ||
1760 | /* This code is placed first in the loop, so that it gets obeyed at the | |
9ee44efb PP |
1761 | start, before the first wait, for the queue-runner case, so that the first |
1762 | one can be started immediately. | |
1763 | ||
1764 | The other option is that we have an inetd wait timeout specified to -bw. */ | |
059ec3d9 PH |
1765 | |
1766 | if (sigalrm_seen) | |
1767 | { | |
9ee44efb PP |
1768 | if (inetd_wait_timeout > 0) |
1769 | { | |
1770 | time_t resignal_interval = inetd_wait_timeout; | |
1771 | ||
1772 | if (last_connection_time == (time_t)0) | |
1773 | { | |
1774 | DEBUG(D_any) | |
1775 | debug_printf("inetd wait timeout expired, but still not seen first message, ignoring\n"); | |
1776 | } | |
1777 | else | |
1778 | { | |
1779 | time_t now = time(NULL); | |
1780 | if (now == (time_t)-1) | |
1781 | { | |
1782 | DEBUG(D_any) debug_printf("failed to get time: %s\n", strerror(errno)); | |
1783 | } | |
1784 | else | |
1785 | { | |
1786 | if ((now - last_connection_time) >= inetd_wait_timeout) | |
1787 | { | |
1788 | DEBUG(D_any) | |
1789 | debug_printf("inetd wait timeout %d expired, ending daemon\n", | |
1790 | inetd_wait_timeout); | |
1791 | log_write(0, LOG_MAIN, "exim %s daemon terminating, inetd wait timeout reached.\n", | |
1792 | version_string); | |
1793 | exit(EXIT_SUCCESS); | |
1794 | } | |
1795 | else | |
1796 | { | |
1797 | resignal_interval -= (now - last_connection_time); | |
1798 | } | |
1799 | } | |
1800 | } | |
059ec3d9 | 1801 | |
9ee44efb | 1802 | sigalrm_seen = FALSE; |
c2a1bba0 | 1803 | ALARM(resignal_interval); |
9ee44efb | 1804 | } |
059ec3d9 | 1805 | |
9ee44efb | 1806 | else |
059ec3d9 | 1807 | { |
9ee44efb | 1808 | DEBUG(D_any) debug_printf("SIGALRM received\n"); |
8e669ac1 | 1809 | |
9ee44efb PP |
1810 | /* Do a full queue run in a child process, if required, unless we already |
1811 | have enough queue runners on the go. If we are not running as root, a | |
1812 | re-exec is required. */ | |
059ec3d9 | 1813 | |
9ee44efb | 1814 | if (queue_interval > 0 && |
0cd5fd23 | 1815 | (local_queue_run_max <= 0 || queue_run_count < local_queue_run_max)) |
9ee44efb PP |
1816 | { |
1817 | if ((pid = fork()) == 0) | |
1818 | { | |
1819 | int sk; | |
3d235903 | 1820 | |
9ee44efb PP |
1821 | DEBUG(D_any) debug_printf("Starting queue-runner: pid %d\n", |
1822 | (int)getpid()); | |
8e669ac1 | 1823 | |
9ee44efb PP |
1824 | /* Disable debugging if it's required only for the daemon process. We |
1825 | leave the above message, because it ties up with the "child ended" | |
1826 | debugging messages. */ | |
059ec3d9 | 1827 | |
8768d548 | 1828 | if (f.debug_daemon) debug_selector = 0; |
059ec3d9 | 1829 | |
9ee44efb | 1830 | /* Close any open listening sockets in the child */ |
059ec3d9 | 1831 | |
9ee44efb PP |
1832 | for (sk = 0; sk < listen_socket_count; sk++) |
1833 | (void)close(listen_sockets[sk]); | |
059ec3d9 | 1834 | |
9ee44efb | 1835 | /* Reset SIGHUP and SIGCHLD in the child in both cases. */ |
059ec3d9 | 1836 | |
9ee44efb PP |
1837 | signal(SIGHUP, SIG_DFL); |
1838 | signal(SIGCHLD, SIG_DFL); | |
059ec3d9 | 1839 | |
9ee44efb PP |
1840 | /* Re-exec if privilege has been given up, unless deliver_drop_ |
1841 | privilege is set. Reset SIGALRM before exec(). */ | |
4fbcfc2e | 1842 | |
9ee44efb | 1843 | if (geteuid() != root_uid && !deliver_drop_privilege) |
4fbcfc2e | 1844 | { |
9ee44efb PP |
1845 | uschar opt[8]; |
1846 | uschar *p = opt; | |
1847 | uschar *extra[5]; | |
1848 | int extracount = 1; | |
1849 | ||
1850 | signal(SIGALRM, SIG_DFL); | |
1851 | *p++ = '-'; | |
1852 | *p++ = 'q'; | |
8768d548 JH |
1853 | if (f.queue_2stage) *p++ = 'q'; |
1854 | if (f.queue_run_first_delivery) *p++ = 'i'; | |
1855 | if (f.queue_run_force) *p++ = 'f'; | |
1856 | if (f.deliver_force_thaw) *p++ = 'f'; | |
1857 | if (f.queue_run_local) *p++ = 'l'; | |
9ee44efb | 1858 | *p = 0; |
e37f8a84 JH |
1859 | extra[0] = queue_name |
1860 | ? string_sprintf("%sG%s", opt, queue_name) : opt; | |
9ee44efb PP |
1861 | |
1862 | /* If -R or -S were on the original command line, ensure they get | |
1863 | passed on. */ | |
1864 | ||
e37f8a84 | 1865 | if (deliver_selectstring) |
9ee44efb | 1866 | { |
8768d548 | 1867 | extra[extracount++] = f.deliver_selectstring_regex ? US"-Rr" : US"-R"; |
9ee44efb PP |
1868 | extra[extracount++] = deliver_selectstring; |
1869 | } | |
1870 | ||
e37f8a84 | 1871 | if (deliver_selectstring_sender) |
9ee44efb | 1872 | { |
8768d548 | 1873 | extra[extracount++] = f.deliver_selectstring_sender_regex |
e37f8a84 | 1874 | ? US"-Sr" : US"-S"; |
9ee44efb PP |
1875 | extra[extracount++] = deliver_selectstring_sender; |
1876 | } | |
1877 | ||
1878 | /* Overlay this process with a new execution. */ | |
1879 | ||
1880 | (void)child_exec_exim(CEE_EXEC_PANIC, FALSE, NULL, TRUE, extracount, | |
1881 | extra[0], extra[1], extra[2], extra[3], extra[4]); | |
1882 | ||
1883 | /* Control never returns here. */ | |
4fbcfc2e PH |
1884 | } |
1885 | ||
9ee44efb | 1886 | /* No need to re-exec; SIGALRM remains set to the default handler */ |
059ec3d9 | 1887 | |
9ee44efb PP |
1888 | queue_run(NULL, NULL, FALSE); |
1889 | _exit(EXIT_SUCCESS); | |
059ec3d9 PH |
1890 | } |
1891 | ||
9ee44efb | 1892 | if (pid < 0) |
059ec3d9 | 1893 | { |
9ee44efb PP |
1894 | log_write(0, LOG_MAIN|LOG_PANIC, "daemon: fork of queue-runner " |
1895 | "process failed: %s", strerror(errno)); | |
1896 | log_close_all(); | |
1897 | } | |
1898 | else | |
1899 | { | |
1900 | int i; | |
0cd5fd23 | 1901 | for (i = 0; i < local_queue_run_max; ++i) |
9ee44efb PP |
1902 | if (queue_pid_slots[i] <= 0) |
1903 | { | |
1904 | queue_pid_slots[i] = pid; | |
1905 | queue_run_count++; | |
1906 | break; | |
1907 | } | |
9ee44efb PP |
1908 | DEBUG(D_any) debug_printf("%d queue-runner process%s running\n", |
1909 | queue_run_count, (queue_run_count == 1)? "" : "es"); | |
059ec3d9 | 1910 | } |
059ec3d9 | 1911 | } |
059ec3d9 | 1912 | |
9ee44efb | 1913 | /* Reset the alarm clock */ |
059ec3d9 | 1914 | |
9ee44efb | 1915 | sigalrm_seen = FALSE; |
c2a1bba0 | 1916 | ALARM(queue_interval); |
9ee44efb PP |
1917 | } |
1918 | ||
1919 | } /* sigalrm_seen */ | |
059ec3d9 PH |
1920 | |
1921 | ||
1922 | /* Sleep till a connection happens if listening, and handle the connection if | |
1923 | that is why we woke up. The FreeBSD operating system requires the use of | |
1924 | select() before accept() because the latter function is not interrupted by | |
1925 | a signal, and we want to wake up for SIGCHLD and SIGALRM signals. Some other | |
1926 | OS do notice signals in accept() but it does no harm to have the select() | |
1927 | in for all of them - and it won't then be a lurking problem for ports to | |
1928 | new OS. In fact, the later addition of listening on specific interfaces only | |
1929 | requires this way of working anyway. */ | |
1930 | ||
8768d548 | 1931 | if (f.daemon_listen) |
059ec3d9 | 1932 | { |
bb6e88ff | 1933 | int sk, lcount, select_errno; |
059ec3d9 PH |
1934 | int max_socket = 0; |
1935 | BOOL select_failed = FALSE; | |
1936 | fd_set select_listen; | |
1937 | ||
1938 | FD_ZERO(&select_listen); | |
1939 | for (sk = 0; sk < listen_socket_count; sk++) | |
1940 | { | |
1941 | FD_SET(listen_sockets[sk], &select_listen); | |
1942 | if (listen_sockets[sk] > max_socket) max_socket = listen_sockets[sk]; | |
1943 | } | |
1944 | ||
1945 | DEBUG(D_any) debug_printf("Listening...\n"); | |
8e669ac1 PH |
1946 | |
1947 | /* In rare cases we may have had a SIGCHLD signal in the time between | |
1948 | setting the handler (below) and getting back here. If so, pretend that the | |
7d468ab8 | 1949 | select() was interrupted so that we reap the child. This might still leave |
8e669ac1 | 1950 | a small window when a SIGCHLD could get lost. However, since we use SIGCHLD |
7d468ab8 PH |
1951 | only to do the reaping more quickly, it shouldn't result in anything other |
1952 | than a delay until something else causes a wake-up. */ | |
1953 | ||
1954 | if (sigchld_seen) | |
1955 | { | |
1956 | lcount = -1; | |
8e669ac1 | 1957 | errno = EINTR; |
7d468ab8 PH |
1958 | } |
1959 | else | |
7d468ab8 PH |
1960 | lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen, |
1961 | NULL, NULL, NULL); | |
059ec3d9 | 1962 | |
7d468ab8 | 1963 | if (lcount < 0) |
059ec3d9 PH |
1964 | { |
1965 | select_failed = TRUE; | |
1966 | lcount = 1; | |
1967 | } | |
8e669ac1 PH |
1968 | |
1969 | /* Clean up any subprocesses that may have terminated. We need to do this | |
1970 | here so that smtp_accept_max_per_host works when a connection to that host | |
1971 | has completed, and we are about to accept a new one. When this code was | |
1972 | later in the sequence, a new connection could be rejected, even though an | |
1973 | old one had just finished. Preserve the errno from any select() failure for | |
bb6e88ff | 1974 | the use of the common select/accept error processing below. */ |
8e669ac1 | 1975 | |
bb6e88ff PH |
1976 | select_errno = errno; |
1977 | handle_ending_processes(); | |
8e669ac1 PH |
1978 | errno = select_errno; |
1979 | ||
059ec3d9 | 1980 | /* Loop for all the sockets that are currently ready to go. If select |
7d468ab8 PH |
1981 | actually failed, we have set the count to 1 and select_failed=TRUE, so as |
1982 | to use the common error code for select/accept below. */ | |
059ec3d9 PH |
1983 | |
1984 | while (lcount-- > 0) | |
1985 | { | |
1986 | int accept_socket = -1; | |
6851a9c5 | 1987 | |
059ec3d9 | 1988 | if (!select_failed) |
059ec3d9 | 1989 | for (sk = 0; sk < listen_socket_count; sk++) |
059ec3d9 PH |
1990 | if (FD_ISSET(listen_sockets[sk], &select_listen)) |
1991 | { | |
cf73943b | 1992 | len = sizeof(accepted); |
059ec3d9 PH |
1993 | accept_socket = accept(listen_sockets[sk], |
1994 | (struct sockaddr *)&accepted, &len); | |
1995 | FD_CLR(listen_sockets[sk], &select_listen); | |
1996 | break; | |
1997 | } | |
059ec3d9 PH |
1998 | |
1999 | /* If select or accept has failed and this was not caused by an | |
2000 | interruption, log the incident and try again. With asymmetric TCP/IP | |
2001 | routing errors such as "No route to network" have been seen here. Also | |
2002 | "connection reset by peer" has been seen. These cannot be classed as | |
2003 | disastrous errors, but they could fill up a lot of log. The code in smail | |
2004 | crashes the daemon after 10 successive failures of accept, on the grounds | |
2005 | that some OS fail continuously. Exim originally followed suit, but this | |
2006 | appears to have caused problems. Now it just keeps going, but instead of | |
2007 | logging each error, it batches them up when they are continuous. */ | |
2008 | ||
2009 | if (accept_socket < 0 && errno != EINTR) | |
2010 | { | |
2011 | if (accept_retry_count == 0) | |
2012 | { | |
2013 | accept_retry_errno = errno; | |
2014 | accept_retry_select_failed = select_failed; | |
2015 | } | |
2016 | else | |
2017 | { | |
2018 | if (errno != accept_retry_errno || | |
2019 | select_failed != accept_retry_select_failed || | |
2020 | accept_retry_count >= 50) | |
2021 | { | |
2022 | log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0), | |
2023 | "%d %s() failure%s: %s", | |
2024 | accept_retry_count, | |
2025 | accept_retry_select_failed? "select" : "accept", | |
2026 | (accept_retry_count == 1)? "" : "s", | |
2027 | strerror(accept_retry_errno)); | |
2028 | log_close_all(); | |
2029 | accept_retry_count = 0; | |
2030 | accept_retry_errno = errno; | |
2031 | accept_retry_select_failed = select_failed; | |
2032 | } | |
2033 | } | |
2034 | accept_retry_count++; | |
2035 | } | |
2036 | ||
2037 | else | |
2038 | { | |
2039 | if (accept_retry_count > 0) | |
2040 | { | |
2041 | log_write(0, LOG_MAIN, "%d %s() failure%s: %s", | |
2042 | accept_retry_count, | |
2043 | accept_retry_select_failed? "select" : "accept", | |
2044 | (accept_retry_count == 1)? "" : "s", | |
2045 | strerror(accept_retry_errno)); | |
2046 | log_close_all(); | |
2047 | accept_retry_count = 0; | |
2048 | } | |
2049 | } | |
2050 | ||
2051 | /* If select/accept succeeded, deal with the connection. */ | |
2052 | ||
2053 | if (accept_socket >= 0) | |
9ee44efb PP |
2054 | { |
2055 | if (inetd_wait_timeout) | |
2056 | last_connection_time = time(NULL); | |
059ec3d9 PH |
2057 | handle_smtp_call(listen_sockets, listen_socket_count, accept_socket, |
2058 | (struct sockaddr *)&accepted); | |
9ee44efb | 2059 | } |
059ec3d9 PH |
2060 | } |
2061 | } | |
2062 | ||
2063 | /* If not listening, then just sleep for the queue interval. If we woke | |
2064 | up early the last time for some other signal, it won't matter because | |
2065 | the alarm signal will wake at the right time. This code originally used | |
2066 | sleep() but it turns out that on the FreeBSD system, sleep() is not inter- | |
2067 | rupted by signals, so it wasn't waking up for SIGALRM or SIGCHLD. Luckily | |
2068 | select() can be used as an interruptible sleep() on all versions of Unix. */ | |
2069 | ||
2070 | else | |
2071 | { | |
2072 | struct timeval tv; | |
2073 | tv.tv_sec = queue_interval; | |
2074 | tv.tv_usec = 0; | |
2075 | select(0, NULL, NULL, NULL, &tv); | |
8e669ac1 | 2076 | handle_ending_processes(); |
059ec3d9 PH |
2077 | } |
2078 | ||
2079 | /* Re-enable the SIGCHLD handler if it has been run. It can't do it | |
2080 | for itself, because it isn't doing the waiting itself. */ | |
2081 | ||
2082 | if (sigchld_seen) | |
2083 | { | |
2084 | sigchld_seen = FALSE; | |
7d468ab8 | 2085 | os_non_restarting_signal(SIGCHLD, main_sigchld_handler); |
059ec3d9 PH |
2086 | } |
2087 | ||
2088 | /* Handle being woken by SIGHUP. We know at this point that the result | |
2089 | of accept() has been dealt with, so we can re-exec exim safely, first | |
2090 | closing the listening sockets so that they can be reused. Cancel any pending | |
2091 | alarm in case it is just about to go off, and set SIGHUP to be ignored so | |
2092 | that another HUP in quick succession doesn't clobber the new daemon before it | |
2093 | gets going. All log files get closed by the close-on-exec flag; however, if | |
2094 | the exec fails, we need to close the logs. */ | |
2095 | ||
2096 | if (sighup_seen) | |
2097 | { | |
2098 | int sk; | |
2099 | log_write(0, LOG_MAIN, "pid %d: SIGHUP received: re-exec daemon", | |
2100 | getpid()); | |
f1e894f3 PH |
2101 | for (sk = 0; sk < listen_socket_count; sk++) |
2102 | (void)close(listen_sockets[sk]); | |
c2a1bba0 | 2103 | ALARM_CLR(0); |
059ec3d9 PH |
2104 | signal(SIGHUP, SIG_IGN); |
2105 | sighup_argv[0] = exim_path; | |
2106 | exim_nullstd(); | |
2107 | execv(CS exim_path, (char *const *)sighup_argv); | |
2108 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid %d: exec of %s failed: %s", | |
2109 | getpid(), exim_path, strerror(errno)); | |
2110 | log_close_all(); | |
2111 | } | |
2112 | ||
2113 | } /* End of main loop */ | |
2114 | ||
2115 | /* Control never reaches here */ | |
2116 | } | |
2117 | ||
071c51f7 JH |
2118 | /* vi: aw ai sw=2 |
2119 | */ | |
059ec3d9 | 2120 | /* End of exim_daemon.c */ |