1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include "apr_portable.h"
19 #include "apr_strings.h"
20 #include "apr_thread_proc.h"
21 #include "apr_signal.h"
23 #define APR_WANT_STDIO
24 #define APR_WANT_STRFUNC
30 #if APR_HAVE_SYS_TYPES_H
31 #include <sys/types.h>
36 #include "ap_config.h"
38 #include "mpm_default.h"
39 #include "http_main.h"
41 #include "http_config.h"
42 #include "http_core.h" /* for get_remote_host */
43 #include "http_connection.h"
44 #include "scoreboard.h"
47 #include "mpm_common.h"
48 #include "ap_listen.h"
53 #include <bstring.h> /* for IRIX, FD_SET calls bzero() */
58 #ifdef HAVE_SYS_PROCESSOR_H
59 #include <sys/processor.h> /* for bindprocessor() */
63 #include <sys/times.h>
65 /* Limit on the total --- clients will be locked out if more servers than
66 * this are needed. It is intended solely to keep the server from crashing
67 * when things get out of hand.
69 * We keep a hard maximum number of servers, for two reasons --- first off,
70 * in case something goes seriously wrong, we want to stop the fork bomb
71 * short of actually crashing the machine we're running on by filling some
72 * kernel table. Secondly, it keeps the size of the scoreboard file small
73 * enough that we can read the whole thing without worrying too much about
76 #ifndef DEFAULT_SERVER_LIMIT
77 #define DEFAULT_SERVER_LIMIT 256
80 /* Admin can't tune ServerLimit beyond MAX_SERVER_LIMIT. We want
81 * some sort of compile-time limit to help catch typos.
83 #ifndef MAX_SERVER_LIMIT
84 #define MAX_SERVER_LIMIT 200000
87 #ifndef HARD_THREAD_LIMIT
88 #define HARD_THREAD_LIMIT 1
93 int ap_threads_per_child=0; /* Worker threads per child */
94 static apr_proc_mutex_t *accept_mutex;
95 static int ap_daemons_to_start=0;
96 static int ap_daemons_min_free=0;
97 static int ap_daemons_max_free=0;
98 static int ap_daemons_limit=0; /* MaxClients */
99 static int server_limit = 0;
100 static int first_server_limit = 0;
101 static int mpm_state = AP_MPMQ_STARTING;
102 static ap_pod_t *pod;
105 * The max child slot ever assigned, preserved across restarts. Necessary
106 * to deal with MaxClients changes across AP_SIG_GRACEFUL restarts. We
107 * use this value to optimize routines that have to scan the entire scoreboard.
109 int ap_max_daemons_limit = -1;
110 server_rec *ap_server_conf;
112 /* one_process --- debugging mode variable; can be set from the command line
113 * with the -X flag. If set, this gets you the child_main loop running
114 * in the process which originally started up (no detach, no make_child),
115 * which is a pretty nice debugging environment. (You'll get a SIGHUP
116 * early in standalone_main; just continue through. This is the server
117 * trying to kill off any child processes which it might have lying
118 * around --- Apache doesn't keep track of their pids, it just sends
119 * SIGHUP to the process group, ignoring it in the root process.
120 * Continue through and you'll be fine.).
123 static int one_process = 0;
125 static apr_pool_t *pconf; /* Pool for config stuff */
126 static apr_pool_t *pchild; /* Pool for httpd child stuff */
128 static pid_t ap_my_pid; /* it seems silly to call getpid all the time */
129 static pid_t parent_pid;
131 static int my_child_num;
133 ap_generation_t volatile ap_my_generation=0;
137 char tpf_server_name[INETD_SERVNAME_LENGTH+1];
140 static volatile int die_now = 0;
144 * change directory for gprof to plop the gmon.out file
145 * configure in httpd.conf:
146 * GprofDir $RuntimeDir/ -> $ServerRoot/$RuntimeDir/gmon.out
147 * GprofDir $RuntimeDir/% -> $ServerRoot/$RuntimeDir/gprof.$pid/gmon.out
149 static void chdir_for_gprof(void)
151 core_server_config *sconf =
152 ap_get_module_config(ap_server_conf->module_config, &core_module);
153 char *dir = sconf->gprof_dir;
159 int len = strlen(sconf->gprof_dir) - 1;
160 if(*(dir + len) == '%') {
162 buf = ap_append_pid(pconf, dir, "gprof.");
164 use_dir = ap_server_root_relative(pconf, buf ? buf : dir);
165 res = apr_dir_make(use_dir,
166 APR_UREAD | APR_UWRITE | APR_UEXECUTE |
167 APR_GREAD | APR_GEXECUTE |
168 APR_WREAD | APR_WEXECUTE, pconf);
169 if(res != APR_SUCCESS && !APR_STATUS_IS_EEXIST(res)) {
170 ap_log_error(APLOG_MARK, APLOG_ERR, res, ap_server_conf,
171 "gprof: error creating directory %s", dir);
175 use_dir = ap_server_root_relative(pconf, DEFAULT_REL_RUNTIMEDIR);
181 #define chdir_for_gprof()
184 /* XXX - I don't know if TPF will ever use this module or not, so leave
185 * the ap_check_signals calls in but disable them - manoj */
186 #define ap_check_signals()
188 /* a clean exit from a child with proper cleanup */
189 static void clean_child_exit(int code) __attribute__ ((noreturn));
190 static void clean_child_exit(int code)
192 mpm_state = AP_MPMQ_STOPPING;
195 apr_pool_destroy(pchild);
197 ap_mpm_pod_close(pod);
202 static void accept_mutex_on(void)
204 apr_status_t rv = apr_proc_mutex_lock(accept_mutex);
205 if (rv != APR_SUCCESS) {
206 const char *msg = "couldn't grab the accept mutex";
208 if (ap_my_generation !=
209 ap_scoreboard_image->global->running_generation) {
210 ap_log_error(APLOG_MARK, APLOG_DEBUG, rv, NULL, "%s", msg);
214 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, NULL, "%s", msg);
215 exit(APEXIT_CHILDFATAL);
220 static void accept_mutex_off(void)
222 apr_status_t rv = apr_proc_mutex_unlock(accept_mutex);
223 if (rv != APR_SUCCESS) {
224 const char *msg = "couldn't release the accept mutex";
226 if (ap_my_generation !=
227 ap_scoreboard_image->global->running_generation) {
228 ap_log_error(APLOG_MARK, APLOG_DEBUG, rv, NULL, "%s", msg);
229 /* don't exit here... we have a connection to
230 * process, after which point we'll see that the
231 * generation changed and we'll exit cleanly
235 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, NULL, "%s", msg);
236 exit(APEXIT_CHILDFATAL);
241 /* On some architectures it's safe to do unserialized accept()s in the single
242 * Listen case. But it's never safe to do it in the case where there's
243 * multiple Listen statements. Define SINGLE_LISTEN_UNSERIALIZED_ACCEPT
244 * when it's safe in the single Listen case.
246 #ifdef SINGLE_LISTEN_UNSERIALIZED_ACCEPT
247 #define SAFE_ACCEPT(stmt) do {if (ap_listeners->next) {stmt;}} while(0)
249 #define SAFE_ACCEPT(stmt) do {stmt;} while(0)
252 AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result)
255 case AP_MPMQ_MAX_DAEMON_USED:
256 *result = ap_daemons_limit;
258 case AP_MPMQ_IS_THREADED:
259 *result = AP_MPMQ_NOT_SUPPORTED;
261 case AP_MPMQ_IS_FORKED:
262 *result = AP_MPMQ_DYNAMIC;
264 case AP_MPMQ_HARD_LIMIT_DAEMONS:
265 *result = server_limit;
267 case AP_MPMQ_HARD_LIMIT_THREADS:
268 *result = HARD_THREAD_LIMIT;
270 case AP_MPMQ_MAX_THREADS:
273 case AP_MPMQ_MIN_SPARE_DAEMONS:
274 *result = ap_daemons_min_free;
276 case AP_MPMQ_MIN_SPARE_THREADS:
279 case AP_MPMQ_MAX_SPARE_DAEMONS:
280 *result = ap_daemons_max_free;
282 case AP_MPMQ_MAX_SPARE_THREADS:
285 case AP_MPMQ_MAX_REQUESTS_DAEMON:
286 *result = ap_max_requests_per_child;
288 case AP_MPMQ_MAX_DAEMONS:
289 *result = server_limit;
291 case AP_MPMQ_MPM_STATE:
298 /*****************************************************************
299 * Connection structures and accounting...
302 static void just_die(int sig)
307 static void stop_listening(int sig)
309 ap_close_listeners();
311 /* For a graceful stop, we want the child to exit when done */
315 /* volatile just in case */
316 static int volatile shutdown_pending;
317 static int volatile restart_pending;
318 static int volatile is_graceful;
320 static void sig_term(int sig)
322 if (shutdown_pending == 1) {
323 /* Um, is this _probably_ not an error, if the user has
324 * tried to do a shutdown twice quickly, so we won't
325 * worry about reporting it.
329 shutdown_pending = 1;
330 is_graceful = (sig == AP_SIG_GRACEFUL_STOP);
333 /* restart() is the signal handler for SIGHUP and AP_SIG_GRACEFUL
334 * in the parent process, unless running in ONE_PROCESS mode
336 static void restart(int sig)
338 if (restart_pending == 1) {
339 /* Probably not an error - don't bother reporting it */
343 is_graceful = (sig == AP_SIG_GRACEFUL);
346 static void set_signals(void)
348 #ifndef NO_USE_SIGACTION
353 ap_fatal_signal_setup(ap_server_conf, pconf);
356 #ifndef NO_USE_SIGACTION
357 sigemptyset(&sa.sa_mask);
360 sa.sa_handler = sig_term;
361 if (sigaction(SIGTERM, &sa, NULL) < 0)
362 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGTERM)");
363 #ifdef AP_SIG_GRACEFUL_STOP
364 if (sigaction(AP_SIG_GRACEFUL_STOP, &sa, NULL) < 0)
365 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
366 "sigaction(" AP_SIG_GRACEFUL_STOP_STRING ")");
369 if (sigaction(SIGINT, &sa, NULL) < 0)
370 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGINT)");
373 sa.sa_handler = SIG_DFL;
374 if (sigaction(SIGXCPU, &sa, NULL) < 0)
375 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGXCPU)");
378 sa.sa_handler = SIG_DFL;
379 if (sigaction(SIGXFSZ, &sa, NULL) < 0)
380 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGXFSZ)");
383 sa.sa_handler = SIG_IGN;
384 if (sigaction(SIGPIPE, &sa, NULL) < 0)
385 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGPIPE)");
388 /* we want to ignore HUPs and AP_SIG_GRACEFUL while we're busy
391 sigaddset(&sa.sa_mask, SIGHUP);
392 sigaddset(&sa.sa_mask, AP_SIG_GRACEFUL);
393 sa.sa_handler = restart;
394 if (sigaction(SIGHUP, &sa, NULL) < 0)
395 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGHUP)");
396 if (sigaction(AP_SIG_GRACEFUL, &sa, NULL) < 0)
397 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(" AP_SIG_GRACEFUL_STRING ")");
401 apr_signal(SIGXCPU, SIG_DFL);
404 apr_signal(SIGXFSZ, SIG_DFL);
408 apr_signal(SIGTERM, sig_term);
410 apr_signal(SIGHUP, restart);
412 #ifdef AP_SIG_GRACEFUL
413 apr_signal(AP_SIG_GRACEFUL, restart);
414 #endif /* AP_SIG_GRACEFUL */
415 #ifdef AP_SIG_GRACEFUL_STOP
416 apr_signal(AP_SIG_GRACEFUL_STOP, sig_term);
417 #endif /* AP_SIG_GRACEFUL */
419 apr_signal(SIGPIPE, SIG_IGN);
425 /*****************************************************************
426 * Child process main loop.
427 * The following vars are static to avoid getting clobbered by longjmp();
428 * they are really private to child_main.
431 static int requests_this_child;
432 static int num_listensocks = 0;
435 int ap_graceful_stop_signalled(void)
437 /* not ever called anymore... */
442 static void child_main(int child_num_arg)
445 apr_allocator_t *allocator;
449 apr_pollset_t *pollset;
451 apr_bucket_alloc_t *bucket_alloc;
452 int last_poll_idx = 0;
454 mpm_state = AP_MPMQ_STARTING; /* for benefit of any hooks that run as this
458 my_child_num = child_num_arg;
459 ap_my_pid = getpid();
460 requests_this_child = 0;
462 ap_fatal_signal_child_setup(ap_server_conf);
464 /* Get a sub context for global allocations in this child, so that
465 * we can have cleanups occur when the child exits.
467 apr_allocator_create(&allocator);
468 apr_allocator_max_free_set(allocator, ap_max_mem_free);
469 apr_pool_create_ex(&pchild, pconf, NULL, allocator);
470 apr_allocator_owner_set(allocator, pchild);
471 apr_pool_tag(pchild, "pchild");
473 apr_pool_create(&ptrans, pchild);
474 apr_pool_tag(ptrans, "transaction");
476 /* needs to be done before we switch UIDs so we have permissions */
477 ap_reopen_scoreboard(pchild, NULL, 0);
478 status = apr_proc_mutex_child_init(&accept_mutex, ap_lock_fname, pchild);
479 if (status != APR_SUCCESS) {
480 ap_log_error(APLOG_MARK, APLOG_EMERG, status, ap_server_conf,
481 "Couldn't initialize cross-process lock in child "
482 "(%s) (%d)", ap_lock_fname, ap_accept_lock_mech);
483 clean_child_exit(APEXIT_CHILDFATAL);
486 if (unixd_setup_child()) {
487 clean_child_exit(APEXIT_CHILDFATAL);
490 ap_run_child_init(pchild, ap_server_conf);
492 ap_create_sb_handle(&sbh, pchild, my_child_num, 0);
494 (void) ap_update_child_status(sbh, SERVER_READY, (request_rec *) NULL);
496 /* Set up the pollfd array */
497 /* ### check the status */
498 (void) apr_pollset_create(&pollset, num_listensocks, pchild, 0);
500 for (lr = ap_listeners, i = num_listensocks; i--; lr = lr->next) {
501 apr_pollfd_t pfd = { 0 };
503 pfd.desc_type = APR_POLL_SOCKET;
505 pfd.reqevents = APR_POLLIN;
506 pfd.client_data = lr;
508 /* ### check the status */
509 (void) apr_pollset_add(pollset, &pfd);
512 mpm_state = AP_MPMQ_RUNNING;
514 bucket_alloc = apr_bucket_alloc_create(pchild);
516 /* die_now is set when AP_SIG_GRACEFUL is received in the child;
517 * shutdown_pending is set when SIGTERM is received when running
518 * in single process mode. */
519 while (!die_now && !shutdown_pending) {
520 conn_rec *current_conn;
524 * (Re)initialize this child to a pre-connection state.
527 apr_pool_clear(ptrans);
529 if ((ap_max_requests_per_child > 0
530 && requests_this_child++ >= ap_max_requests_per_child)) {
534 (void) ap_update_child_status(sbh, SERVER_READY, (request_rec *) NULL);
537 * Wait for an acceptable connection to arrive.
540 /* Lock around "accept", if necessary */
541 SAFE_ACCEPT(accept_mutex_on());
543 if (num_listensocks == 1) {
544 /* There is only one listener record, so refer to that one. */
548 /* multiple listening sockets - need to poll */
551 const apr_pollfd_t *pdesc;
553 /* timeout == -1 == wait forever */
554 status = apr_pollset_poll(pollset, -1, &numdesc, &pdesc);
555 if (status != APR_SUCCESS) {
556 if (APR_STATUS_IS_EINTR(status)) {
557 if (one_process && shutdown_pending) {
561 /* In graceful stop/restart; drop the mutex
562 * and terminate the child. */
563 SAFE_ACCEPT(accept_mutex_off());
568 /* Single Unix documents select as returning errnos
569 * EBADF, EINTR, and EINVAL... and in none of those
570 * cases does it make sense to continue. In fact
571 * on Linux 2.0.x we seem to end up with EFAULT
572 * occasionally, and we'd loop forever due to it.
574 ap_log_error(APLOG_MARK, APLOG_ERR, status,
575 ap_server_conf, "apr_pollset_poll: (listen)");
576 SAFE_ACCEPT(accept_mutex_off());
580 /* We can always use pdesc[0], but sockets at position N
581 * could end up completely starved of attention in a very
582 * busy server. Therefore, we round-robin across the
583 * returned set of descriptors. While it is possible that
584 * the returned set of descriptors might flip around and
585 * continue to starve some sockets, we happen to know the
586 * internal pollset implementation retains ordering
587 * stability of the sockets. Thus, the round-robin should
588 * ensure that a socket will eventually be serviced.
590 if (last_poll_idx >= numdesc)
593 /* Grab a listener record from the client_data of the poll
594 * descriptor, and advance our saved index to round-robin
597 * ### hmm... this descriptor might have POLLERR rather
600 lr = pdesc[last_poll_idx++].client_data;
605 /* if we accept() something we don't want to die, so we have to
608 status = lr->accept_func(&csd, lr, ptrans);
610 SAFE_ACCEPT(accept_mutex_off()); /* unlock after "accept" */
612 if (status == APR_EGENERAL) {
613 /* resource shortage or should-not-occur occured */
616 else if (status != APR_SUCCESS) {
621 * We now have a connection, so set it up with the appropriate
622 * socket options, file descriptors, and read/write buffers.
625 current_conn = ap_run_create_connection(ptrans, ap_server_conf, csd, my_child_num, sbh, bucket_alloc);
627 ap_process_connection(current_conn, csd);
628 ap_lingering_close(current_conn);
631 /* Check the pod and the generation number after processing a
632 * connection so that we'll go away if a graceful restart occurred
633 * while we were processing the connection or we are the lucky
634 * idle server process that gets to die.
636 if (ap_mpm_pod_check(pod) == APR_SUCCESS) { /* selected as idle? */
639 else if (ap_my_generation !=
640 ap_scoreboard_image->global->running_generation) { /* restart? */
641 /* yeah, this could be non-graceful restart, in which case the
642 * parent will kill us soon enough, but why bother checking?
651 static int make_child(server_rec *s, int slot)
655 if (slot + 1 > ap_max_daemons_limit) {
656 ap_max_daemons_limit = slot + 1;
660 apr_signal(SIGHUP, sig_term);
661 /* Don't catch AP_SIG_GRACEFUL in ONE_PROCESS mode :) */
662 apr_signal(SIGINT, sig_term);
664 apr_signal(SIGQUIT, SIG_DFL);
666 apr_signal(SIGTERM, sig_term);
671 (void) ap_update_child_status_from_indexes(slot, 0, SERVER_STARTING,
672 (request_rec *) NULL);
676 /* BS2000 requires a "special" version of fork() before a setuid() call */
677 if ((pid = os_fork(unixd_config.user_name)) == -1) {
679 if ((pid = os_fork(s, slot)) == -1) {
681 if ((pid = fork()) == -1) {
683 ap_log_error(APLOG_MARK, APLOG_ERR, errno, s, "fork: Unable to fork new process");
685 /* fork didn't succeed. Fix the scoreboard or else
686 * it will say SERVER_STARTING forever and ever
688 (void) ap_update_child_status_from_indexes(slot, 0, SERVER_DEAD,
689 (request_rec *) NULL);
691 /* In case system resources are maxxed out, we don't want
692 * Apache running away with the CPU trying to fork over and
693 * over and over again.
701 #ifdef HAVE_BINDPROCESSOR
702 /* by default AIX binds to a single processor
703 * this bit unbinds children which will then bind to another cpu
705 int status = bindprocessor(BINDPROCESS, (int)getpid(),
706 PROCESSOR_CLASS_ANY);
708 ap_log_error(APLOG_MARK, APLOG_WARNING, errno,
709 ap_server_conf, "processor unbind failed %d", status);
712 RAISE_SIGSTOP(MAKE_CHILD);
714 /* Disable the parent's signal handlers and set up proper handling in
717 apr_signal(SIGHUP, just_die);
718 apr_signal(SIGTERM, just_die);
719 /* The child process just closes listeners on AP_SIG_GRACEFUL.
720 * The pod is used for signalling the graceful restart.
722 apr_signal(AP_SIG_GRACEFUL, stop_listening);
726 ap_scoreboard_image->parent[slot].pid = pid;
732 /* start up a bunch of children */
733 static void startup_children(int number_to_start)
737 for (i = 0; number_to_start && i < ap_daemons_limit; ++i) {
738 if (ap_scoreboard_image->servers[i][0].status != SERVER_DEAD) {
741 if (make_child(ap_server_conf, i) < 0) {
750 * idle_spawn_rate is the number of children that will be spawned on the
751 * next maintenance cycle if there aren't enough idle servers. It is
752 * doubled up to MAX_SPAWN_RATE, and reset only when a cycle goes by
753 * without the need to spawn.
755 static int idle_spawn_rate = 1;
756 #ifndef MAX_SPAWN_RATE
757 #define MAX_SPAWN_RATE (32)
759 static int hold_off_on_exponential_spawning;
761 static void perform_idle_server_maintenance(apr_pool_t *p)
768 int free_slots[MAX_SPAWN_RATE];
772 /* initialize the free_list */
780 for (i = 0; i < ap_daemons_limit; ++i) {
783 if (i >= ap_max_daemons_limit && free_length == idle_spawn_rate)
785 ws = &ap_scoreboard_image->servers[i][0];
787 if (status == SERVER_DEAD) {
788 /* try to keep children numbers as low as possible */
789 if (free_length < idle_spawn_rate) {
790 free_slots[free_length] = i;
795 /* We consider a starting server as idle because we started it
796 * at least a cycle ago, and if it still hasn't finished starting
797 * then we're just going to swamp things worse by forking more.
798 * So we hopefully won't need to fork more if we count it.
799 * This depends on the ordering of SERVER_READY and SERVER_STARTING.
801 if (status <= SERVER_READY) {
803 /* always kill the highest numbered child if we have to...
804 * no really well thought out reason ... other than observing
805 * the server behaviour under linux where lower numbered children
806 * tend to service more hits (and hence are more likely to have
807 * their data in cpu caches).
816 ap_max_daemons_limit = last_non_dead + 1;
817 if (idle_count > ap_daemons_max_free) {
818 /* kill off one child... we use the pod because that'll cause it to
819 * shut down gracefully, in case it happened to pick up a request
820 * while we were counting
822 ap_mpm_pod_signal(pod);
825 else if (idle_count < ap_daemons_min_free) {
826 /* terminate the free list */
827 if (free_length == 0) {
828 /* only report this condition once */
829 static int reported = 0;
832 ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf,
833 "server reached MaxClients setting, consider"
834 " raising the MaxClients setting");
840 if (idle_spawn_rate >= 8) {
841 ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf,
842 "server seems busy, (you may need "
843 "to increase StartServers, or Min/MaxSpareServers), "
844 "spawning %d children, there are %d idle, and "
845 "%d total children", idle_spawn_rate,
846 idle_count, total_non_dead);
848 for (i = 0; i < free_length; ++i) {
850 if (make_child(ap_server_conf, free_slots[i]) == -1) {
851 if(free_length == 1) {
852 shutdown_pending = 1;
853 ap_log_error(APLOG_MARK, APLOG_EMERG, 0, ap_server_conf,
854 "No active child processes: shutting down");
858 make_child(ap_server_conf, free_slots[i]);
861 /* the next time around we want to spawn twice as many if this
862 * wasn't good enough, but not if we've just done a graceful
864 if (hold_off_on_exponential_spawning) {
865 --hold_off_on_exponential_spawning;
867 else if (idle_spawn_rate < MAX_SPAWN_RATE) {
868 idle_spawn_rate *= 2;
877 /*****************************************************************
878 * Executive routines.
881 int ap_mpm_run(apr_pool_t *_pconf, apr_pool_t *plog, server_rec *s)
884 int remaining_children_to_start;
887 ap_log_pid(pconf, ap_pid_fname);
889 /* Initialize cross-process accept lock */
890 ap_lock_fname = apr_psprintf(_pconf, "%s.%" APR_PID_T_FMT,
891 ap_server_root_relative(_pconf, ap_lock_fname),
894 rv = apr_proc_mutex_create(&accept_mutex, ap_lock_fname,
895 ap_accept_lock_mech, _pconf);
896 if (rv != APR_SUCCESS) {
897 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
898 "Couldn't create accept lock (%s) (%d)",
899 ap_lock_fname, ap_accept_lock_mech);
900 mpm_state = AP_MPMQ_STOPPING;
904 #if APR_USE_SYSVSEM_SERIALIZE
905 if (ap_accept_lock_mech == APR_LOCK_DEFAULT ||
906 ap_accept_lock_mech == APR_LOCK_SYSVSEM) {
908 if (ap_accept_lock_mech == APR_LOCK_SYSVSEM) {
910 rv = unixd_set_proc_mutex_perms(accept_mutex);
911 if (rv != APR_SUCCESS) {
912 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
913 "Couldn't set permissions on cross-process lock; "
914 "check User and Group directives");
915 mpm_state = AP_MPMQ_STOPPING;
921 if (ap_run_pre_mpm(s->process->pool, SB_SHARED) != OK) {
922 mpm_state = AP_MPMQ_STOPPING;
925 /* fix the generation number in the global score; we just got a new,
928 ap_scoreboard_image->global->running_generation = ap_my_generation;
935 make_child(ap_server_conf, 0);
938 if (ap_daemons_max_free < ap_daemons_min_free + 1) /* Don't thrash... */
939 ap_daemons_max_free = ap_daemons_min_free + 1;
941 /* If we're doing a graceful_restart then we're going to see a lot
942 * of children exiting immediately when we get into the main loop
943 * below (because we just sent them AP_SIG_GRACEFUL). This happens pretty
944 * rapidly... and for each one that exits we'll start a new one until
945 * we reach at least daemons_min_free. But we may be permitted to
946 * start more than that, so we'll just keep track of how many we're
947 * supposed to start up without the 1 second penalty between each fork.
949 remaining_children_to_start = ap_daemons_to_start;
950 if (remaining_children_to_start > ap_daemons_limit) {
951 remaining_children_to_start = ap_daemons_limit;
954 startup_children(remaining_children_to_start);
955 remaining_children_to_start = 0;
958 /* give the system some time to recover before kicking into
961 hold_off_on_exponential_spawning = 10;
964 ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
965 "%s configured -- resuming normal operations",
966 ap_get_server_description());
967 ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf,
968 "Server built: %s", ap_get_server_built());
969 #ifdef AP_MPM_WANT_SET_ACCEPT_LOCK_MECH
970 ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
971 "AcceptMutex: %s (default: %s)",
972 apr_proc_mutex_name(accept_mutex),
973 apr_proc_mutex_defname());
975 restart_pending = shutdown_pending = 0;
977 mpm_state = AP_MPMQ_RUNNING;
979 while (!restart_pending && !shutdown_pending) {
981 apr_exit_why_e exitwhy;
982 int status, processed_status;
983 /* this is a memory leak, but I'll fix it later. */
986 ap_wait_or_timeout(&exitwhy, &status, &pid, pconf);
988 /* XXX: if it takes longer than 1 second for all our children
989 * to start up and get into IDLE state then we may spawn an
993 processed_status = ap_process_child_status(&pid, exitwhy, status);
994 if (processed_status == APEXIT_CHILDFATAL) {
995 mpm_state = AP_MPMQ_STOPPING;
999 /* non-fatal death... note that it's gone in the scoreboard. */
1000 child_slot = find_child_by_pid(&pid);
1001 if (child_slot >= 0) {
1002 (void) ap_update_child_status_from_indexes(child_slot, 0, SERVER_DEAD,
1003 (request_rec *) NULL);
1004 if (processed_status == APEXIT_CHILDSICK) {
1005 /* child detected a resource shortage (E[NM]FILE, ENOBUFS, etc)
1006 * cut the fork rate to the minimum
1008 idle_spawn_rate = 1;
1010 else if (remaining_children_to_start
1011 && child_slot < ap_daemons_limit) {
1012 /* we're still doing a 1-for-1 replacement of dead
1013 * children with new children
1015 make_child(ap_server_conf, child_slot);
1016 --remaining_children_to_start;
1018 #if APR_HAS_OTHER_CHILD
1020 else if (apr_proc_other_child_alert(&pid, APR_OC_REASON_DEATH, status) == APR_SUCCESS) {
1024 else if (is_graceful) {
1025 /* Great, we've probably just lost a slot in the
1026 * scoreboard. Somehow we don't know about this
1029 ap_log_error(APLOG_MARK, APLOG_WARNING,
1031 "long lost child came home! (pid %ld)", (long)pid.pid);
1033 /* Don't perform idle maintenance when a child dies,
1034 * only do it when there's a timeout. Remember only a
1035 * finite number of children can die, and it's pretty
1036 * pathological for a lot to die suddenly.
1040 else if (remaining_children_to_start) {
1041 /* we hit a 1 second timeout in which none of the previous
1042 * generation of children needed to be reaped... so assume
1043 * they're all done, and pick up the slack if any is left.
1045 startup_children(remaining_children_to_start);
1046 remaining_children_to_start = 0;
1047 /* In any event we really shouldn't do the code below because
1048 * few of the servers we just started are in the IDLE state
1049 * yet, so we'd mistakenly create an extra server.
1054 perform_idle_server_maintenance(pconf);
1056 shutdown_pending = os_check_server(tpf_server_name);
1063 mpm_state = AP_MPMQ_STOPPING;
1065 if (shutdown_pending && !is_graceful) {
1066 /* Time to shut down:
1067 * Kill child processes, tell them to call child_exit, etc...
1069 if (unixd_killpg(getpgrp(), SIGTERM) < 0) {
1070 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "killpg SIGTERM");
1072 ap_reclaim_child_processes(1); /* Start with SIGTERM */
1074 /* cleanup pid file on normal shutdown */
1076 const char *pidfile = NULL;
1077 pidfile = ap_server_root_relative (pconf, ap_pid_fname);
1078 if ( pidfile != NULL && unlink(pidfile) == 0)
1079 ap_log_error(APLOG_MARK, APLOG_INFO,
1081 "removed PID file %s (pid=%ld)",
1082 pidfile, (long)getpid());
1085 ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
1086 "caught SIGTERM, shutting down");
1089 } else if (shutdown_pending) {
1090 /* Time to perform a graceful shut down:
1091 * Reap the inactive children, and ask the active ones
1092 * to close their listeners, then wait until they are
1095 int active_children;
1096 apr_time_t cutoff = 0;
1098 /* Stop listening */
1099 ap_close_listeners();
1101 /* kill off the idle ones */
1102 ap_mpm_pod_killpg(pod, ap_max_daemons_limit);
1104 /* Send SIGUSR1 to the active children */
1105 active_children = 0;
1106 for (index = 0; index < ap_daemons_limit; ++index) {
1107 if (ap_scoreboard_image->servers[index][0].status != SERVER_DEAD) {
1108 /* Ask each child to close its listeners. */
1109 ap_mpm_safe_kill(MPM_CHILD_PID(index), AP_SIG_GRACEFUL);
1114 /* Allow each child which actually finished to exit */
1115 ap_relieve_child_processes();
1117 /* cleanup pid file */
1119 const char *pidfile = NULL;
1120 pidfile = ap_server_root_relative (pconf, ap_pid_fname);
1121 if ( pidfile != NULL && unlink(pidfile) == 0)
1122 ap_log_error(APLOG_MARK, APLOG_INFO,
1124 "removed PID file %s (pid=%ld)",
1125 pidfile, (long)getpid());
1128 ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
1129 "caught " AP_SIG_GRACEFUL_STOP_STRING ", shutting down gracefully");
1131 if (ap_graceful_shutdown_timeout) {
1132 cutoff = apr_time_now() +
1133 apr_time_from_sec(ap_graceful_shutdown_timeout);
1136 /* Don't really exit until each child has finished */
1137 shutdown_pending = 0;
1139 /* Pause for a second */
1142 /* Relieve any children which have now exited */
1143 ap_relieve_child_processes();
1145 active_children = 0;
1146 for (index = 0; index < ap_daemons_limit; ++index) {
1147 if (ap_mpm_safe_kill(MPM_CHILD_PID(index), 0) == APR_SUCCESS) {
1148 active_children = 1;
1149 /* Having just one child is enough to stay around */
1153 } while (!shutdown_pending && active_children &&
1154 (!ap_graceful_shutdown_timeout || apr_time_now() < cutoff));
1156 /* We might be here because we received SIGTERM, either
1157 * way, try and make sure that all of our processes are
1160 unixd_killpg(getpgrp(), SIGTERM);
1165 /* we've been told to restart */
1166 apr_signal(SIGHUP, SIG_IGN);
1167 apr_signal(AP_SIG_GRACEFUL, SIG_IGN);
1169 /* not worth thinking about */
1173 /* advance to the next generation */
1174 /* XXX: we really need to make sure this new generation number isn't in
1175 * use by any of the children.
1178 ap_scoreboard_image->global->running_generation = ap_my_generation;
1181 ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
1182 "Graceful restart requested, doing restart");
1184 /* kill off the idle ones */
1185 ap_mpm_pod_killpg(pod, ap_max_daemons_limit);
1187 /* This is mostly for debugging... so that we know what is still
1188 * gracefully dealing with existing request. This will break
1189 * in a very nasty way if we ever have the scoreboard totally
1190 * file-based (no shared memory)
1192 for (index = 0; index < ap_daemons_limit; ++index) {
1193 if (ap_scoreboard_image->servers[index][0].status != SERVER_DEAD) {
1194 ap_scoreboard_image->servers[index][0].status = SERVER_GRACEFUL;
1195 /* Ask each child to close its listeners.
1197 * NOTE: we use the scoreboard, because if we send SIGUSR1
1198 * to every process in the group, this may include CGI's,
1199 * piped loggers, etc. They almost certainly won't handle
1202 ap_mpm_safe_kill(ap_scoreboard_image->parent[index].pid, AP_SIG_GRACEFUL);
1208 if (unixd_killpg(getpgrp(), SIGHUP) < 0) {
1209 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "killpg SIGHUP");
1211 ap_reclaim_child_processes(0); /* Not when just starting up */
1212 ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
1213 "SIGHUP received. Attempting to restart");
1219 /* This really should be a post_config hook, but the error log is already
1220 * redirected by that point, so we need to do this in the open_logs phase.
1222 static int prefork_open_logs(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s)
1224 static int restart_num = 0;
1226 int level_flags = 0;
1232 /* the reverse of pre_config, we want this only the first time around */
1233 if (restart_num++ == 0) {
1235 level_flags |= APLOG_STARTUP;
1238 if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) {
1239 ap_log_error(APLOG_MARK, APLOG_ALERT | level_flags, 0,
1240 (startup ? NULL : s),
1241 "no listening sockets available, shutting down");
1245 if ((rv = ap_mpm_pod_open(pconf, &pod))) {
1246 ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv,
1247 (startup ? NULL : s),
1248 "could not open pipe-of-death");
1254 static int prefork_pre_config(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp)
1256 static int restart_num = 0;
1257 int no_detach, debug, foreground;
1260 mpm_state = AP_MPMQ_STARTING;
1262 debug = ap_exists_config_define("DEBUG");
1265 foreground = one_process = 1;
1270 no_detach = ap_exists_config_define("NO_DETACH");
1271 one_process = ap_exists_config_define("ONE_PROCESS");
1272 foreground = ap_exists_config_define("FOREGROUND");
1275 /* sigh, want this only the second time around */
1276 if (restart_num++ == 1) {
1279 if (!one_process && !foreground) {
1280 rv = apr_proc_detach(no_detach ? APR_PROC_DETACH_FOREGROUND
1281 : APR_PROC_DETACH_DAEMONIZE);
1282 if (rv != APR_SUCCESS) {
1283 ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL,
1284 "apr_proc_detach failed");
1285 return HTTP_INTERNAL_SERVER_ERROR;
1289 parent_pid = ap_my_pid = getpid();
1292 unixd_pre_config(ptemp);
1293 ap_listen_pre_config();
1294 ap_daemons_to_start = DEFAULT_START_DAEMON;
1295 ap_daemons_min_free = DEFAULT_MIN_FREE_DAEMON;
1296 ap_daemons_max_free = DEFAULT_MAX_FREE_DAEMON;
1297 server_limit = DEFAULT_SERVER_LIMIT;
1298 ap_daemons_limit = server_limit;
1299 ap_pid_fname = DEFAULT_PIDLOG;
1300 ap_lock_fname = DEFAULT_LOCKFILE;
1301 ap_max_requests_per_child = DEFAULT_MAX_REQUESTS_PER_CHILD;
1302 ap_extended_status = 0;
1303 #ifdef AP_MPM_WANT_SET_MAX_MEM_FREE
1304 ap_max_mem_free = APR_ALLOCATOR_MAX_FREE_UNLIMITED;
1307 apr_cpystrn(ap_coredump_dir, ap_server_root, sizeof(ap_coredump_dir));
1312 static int prefork_check_config(apr_pool_t *p, apr_pool_t *plog,
1313 apr_pool_t *ptemp, server_rec *s)
1315 static int restart_num = 0;
1318 /* the reverse of pre_config, we want this only the first time around */
1319 if (restart_num++ == 0) {
1323 if (server_limit > MAX_SERVER_LIMIT) {
1325 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1326 "WARNING: ServerLimit of %d exceeds compile-time "
1327 "limit of", server_limit);
1328 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1329 " %d servers, decreasing to %d.",
1330 MAX_SERVER_LIMIT, MAX_SERVER_LIMIT);
1332 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1333 "ServerLimit of %d exceeds compile-time limit "
1334 "of %d, decreasing to match",
1335 server_limit, MAX_SERVER_LIMIT);
1337 server_limit = MAX_SERVER_LIMIT;
1339 else if (server_limit < 1) {
1341 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1342 "WARNING: ServerLimit of %d not allowed, "
1343 "increasing to 1.", server_limit);
1345 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1346 "ServerLimit of %d not allowed, increasing to 1",
1352 /* you cannot change ServerLimit across a restart; ignore
1355 if (!first_server_limit) {
1356 first_server_limit = server_limit;
1358 else if (server_limit != first_server_limit) {
1359 /* don't need a startup console version here */
1360 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1361 "changing ServerLimit to %d from original value of %d "
1362 "not allowed during restart",
1363 server_limit, first_server_limit);
1364 server_limit = first_server_limit;
1367 if (ap_daemons_limit > server_limit) {
1369 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1370 "WARNING: MaxClients of %d exceeds ServerLimit "
1371 "value of", ap_daemons_limit);
1372 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1373 " %d servers, decreasing MaxClients to %d.",
1374 server_limit, server_limit);
1375 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1376 " To increase, please see the ServerLimit "
1379 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1380 "MaxClients of %d exceeds ServerLimit value "
1381 "of %d, decreasing to match",
1382 ap_daemons_limit, server_limit);
1384 ap_daemons_limit = server_limit;
1386 else if (ap_daemons_limit < 1) {
1388 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1389 "WARNING: MaxClients of %d not allowed, "
1390 "increasing to 1.", ap_daemons_limit);
1392 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1393 "MaxClients of %d not allowed, increasing to 1",
1396 ap_daemons_limit = 1;
1399 /* ap_daemons_to_start > ap_daemons_limit checked in ap_mpm_run() */
1400 if (ap_daemons_to_start < 0) {
1402 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1403 "WARNING: StartServers of %d not allowed, "
1404 "increasing to 1.", ap_daemons_to_start);
1406 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1407 "StartServers of %d not allowed, increasing to 1",
1408 ap_daemons_to_start);
1410 ap_daemons_to_start = 1;
1413 if (ap_daemons_min_free < 1) {
1415 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1416 "WARNING: MinSpareServers of %d not allowed, "
1417 "increasing to 1", ap_daemons_min_free);
1418 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1419 " to avoid almost certain server failure.");
1420 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1421 " Please read the documentation.");
1423 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1424 "MinSpareServers of %d not allowed, increasing to 1",
1425 ap_daemons_min_free);
1427 ap_daemons_min_free = 1;
1430 /* ap_daemons_max_free < ap_daemons_min_free + 1 checked in ap_mpm_run() */
1435 static void prefork_hooks(apr_pool_t *p)
1437 /* Our open_logs hook function must run before the core's, or stderr
1438 * will be redirected to a file, and the messages won't print to the
1441 static const char *const aszSucc[] = {"core.c", NULL};
1447 ap_hook_open_logs(prefork_open_logs, NULL, aszSucc, APR_HOOK_REALLY_FIRST);
1448 /* we need to set the MPM state before other pre-config hooks use MPM query
1449 * to retrieve it, so register as REALLY_FIRST
1451 ap_hook_pre_config(prefork_pre_config, NULL, NULL, APR_HOOK_REALLY_FIRST);
1452 ap_hook_check_config(prefork_check_config, NULL, NULL, APR_HOOK_MIDDLE);
1455 static const char *set_daemons_to_start(cmd_parms *cmd, void *dummy, const char *arg)
1457 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1462 ap_daemons_to_start = atoi(arg);
1466 static const char *set_min_free_servers(cmd_parms *cmd, void *dummy, const char *arg)
1468 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1473 ap_daemons_min_free = atoi(arg);
1477 static const char *set_max_free_servers(cmd_parms *cmd, void *dummy, const char *arg)
1479 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1484 ap_daemons_max_free = atoi(arg);
1488 static const char *set_max_clients (cmd_parms *cmd, void *dummy, const char *arg)
1490 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1495 ap_daemons_limit = atoi(arg);
1499 static const char *set_server_limit (cmd_parms *cmd, void *dummy, const char *arg)
1501 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1506 server_limit = atoi(arg);
1510 static const command_rec prefork_cmds[] = {
1511 UNIX_DAEMON_COMMANDS,
1513 AP_INIT_TAKE1("StartServers", set_daemons_to_start, NULL, RSRC_CONF,
1514 "Number of child processes launched at server startup"),
1515 AP_INIT_TAKE1("MinSpareServers", set_min_free_servers, NULL, RSRC_CONF,
1516 "Minimum number of idle children, to handle request spikes"),
1517 AP_INIT_TAKE1("MaxSpareServers", set_max_free_servers, NULL, RSRC_CONF,
1518 "Maximum number of idle children"),
1519 AP_INIT_TAKE1("MaxClients", set_max_clients, NULL, RSRC_CONF,
1520 "Maximum number of children alive at the same time"),
1521 AP_INIT_TAKE1("ServerLimit", set_server_limit, NULL, RSRC_CONF,
1522 "Maximum value of MaxClients for this run of Apache"),
1523 AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND,
1527 module AP_MODULE_DECLARE_DATA mpm_prefork_module = {
1529 ap_mpm_rewrite_args, /* hook to run before apache parses args */
1530 NULL, /* create per-directory config structure */
1531 NULL, /* merge per-directory config structures */
1532 NULL, /* create per-server config structure */
1533 NULL, /* merge per-server config structures */
1534 prefork_cmds, /* command apr_table_t */
1535 prefork_hooks, /* register hooks */