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>
34 #include "ap_config.h"
36 #include "mpm_default.h"
37 #include "http_main.h"
39 #include "http_config.h"
40 #include "http_core.h" /* for get_remote_host */
41 #include "http_connection.h"
42 #include "scoreboard.h"
45 #include "mpm_common.h"
46 #include "ap_listen.h"
51 #include <bstring.h> /* for IRIX, FD_SET calls bzero() */
56 #ifdef HAVE_SYS_PROCESSOR_H
57 #include <sys/processor.h> /* for bindprocessor() */
61 #include <sys/times.h>
63 /* Limit on the total --- clients will be locked out if more servers than
64 * this are needed. It is intended solely to keep the server from crashing
65 * when things get out of hand.
67 * We keep a hard maximum number of servers, for two reasons --- first off,
68 * in case something goes seriously wrong, we want to stop the fork bomb
69 * short of actually crashing the machine we're running on by filling some
70 * kernel table. Secondly, it keeps the size of the scoreboard file small
71 * enough that we can read the whole thing without worrying too much about
74 #ifndef DEFAULT_SERVER_LIMIT
75 #define DEFAULT_SERVER_LIMIT 256
78 /* Admin can't tune ServerLimit beyond MAX_SERVER_LIMIT. We want
79 * some sort of compile-time limit to help catch typos.
81 #ifndef MAX_SERVER_LIMIT
82 #define MAX_SERVER_LIMIT 200000
85 #ifndef HARD_THREAD_LIMIT
86 #define HARD_THREAD_LIMIT 1
91 int ap_threads_per_child=0; /* Worker threads per child */
92 static apr_proc_mutex_t *accept_mutex;
93 static int ap_daemons_to_start=0;
94 static int ap_daemons_min_free=0;
95 static int ap_daemons_max_free=0;
96 static int ap_daemons_limit=0; /* MaxClients */
97 static int server_limit = 0;
98 static int first_server_limit = 0;
99 static int mpm_state = AP_MPMQ_STARTING;
100 static ap_pod_t *pod;
103 * The max child slot ever assigned, preserved across restarts. Necessary
104 * to deal with MaxClients changes across AP_SIG_GRACEFUL restarts. We
105 * use this value to optimize routines that have to scan the entire scoreboard.
107 int ap_max_daemons_limit = -1;
108 server_rec *ap_server_conf;
110 /* one_process --- debugging mode variable; can be set from the command line
111 * with the -X flag. If set, this gets you the child_main loop running
112 * in the process which originally started up (no detach, no make_child),
113 * which is a pretty nice debugging environment. (You'll get a SIGHUP
114 * early in standalone_main; just continue through. This is the server
115 * trying to kill off any child processes which it might have lying
116 * around --- Apache doesn't keep track of their pids, it just sends
117 * SIGHUP to the process group, ignoring it in the root process.
118 * Continue through and you'll be fine.).
121 static int one_process = 0;
123 static apr_pool_t *pconf; /* Pool for config stuff */
124 static apr_pool_t *pchild; /* Pool for httpd child stuff */
126 static pid_t ap_my_pid; /* it seems silly to call getpid all the time */
127 static pid_t parent_pid;
129 static int my_child_num;
131 ap_generation_t volatile ap_my_generation=0;
135 char tpf_server_name[INETD_SERVNAME_LENGTH+1];
138 static volatile int die_now = 0;
142 * change directory for gprof to plop the gmon.out file
143 * configure in httpd.conf:
144 * GprofDir $RuntimeDir/ -> $ServerRoot/$RuntimeDir/gmon.out
145 * GprofDir $RuntimeDir/% -> $ServerRoot/$RuntimeDir/gprof.$pid/gmon.out
147 static void chdir_for_gprof(void)
149 core_server_config *sconf =
150 ap_get_module_config(ap_server_conf->module_config, &core_module);
151 char *dir = sconf->gprof_dir;
157 int len = strlen(sconf->gprof_dir) - 1;
158 if(*(dir + len) == '%') {
160 buf = ap_append_pid(pconf, dir, "gprof.");
162 use_dir = ap_server_root_relative(pconf, buf ? buf : dir);
163 res = apr_dir_make(use_dir,
164 APR_UREAD | APR_UWRITE | APR_UEXECUTE |
165 APR_GREAD | APR_GEXECUTE |
166 APR_WREAD | APR_WEXECUTE, pconf);
167 if(res != APR_SUCCESS && !APR_STATUS_IS_EEXIST(res)) {
168 ap_log_error(APLOG_MARK, APLOG_ERR, res, ap_server_conf,
169 "gprof: error creating directory %s", dir);
173 use_dir = ap_server_root_relative(pconf, DEFAULT_REL_RUNTIMEDIR);
179 #define chdir_for_gprof()
182 /* XXX - I don't know if TPF will ever use this module or not, so leave
183 * the ap_check_signals calls in but disable them - manoj */
184 #define ap_check_signals()
186 /* a clean exit from a child with proper cleanup */
187 static void clean_child_exit(int code) __attribute__ ((noreturn));
188 static void clean_child_exit(int code)
190 mpm_state = AP_MPMQ_STOPPING;
193 apr_pool_destroy(pchild);
195 ap_mpm_pod_close(pod);
200 static void accept_mutex_on(void)
202 apr_status_t rv = apr_proc_mutex_lock(accept_mutex);
203 if (rv != APR_SUCCESS) {
204 const char *msg = "couldn't grab the accept mutex";
206 if (ap_my_generation !=
207 ap_scoreboard_image->global->running_generation) {
208 ap_log_error(APLOG_MARK, APLOG_DEBUG, rv, NULL, "%s", msg);
212 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, NULL, "%s", msg);
213 exit(APEXIT_CHILDFATAL);
218 static void accept_mutex_off(void)
220 apr_status_t rv = apr_proc_mutex_unlock(accept_mutex);
221 if (rv != APR_SUCCESS) {
222 const char *msg = "couldn't release the accept mutex";
224 if (ap_my_generation !=
225 ap_scoreboard_image->global->running_generation) {
226 ap_log_error(APLOG_MARK, APLOG_DEBUG, rv, NULL, "%s", msg);
227 /* don't exit here... we have a connection to
228 * process, after which point we'll see that the
229 * generation changed and we'll exit cleanly
233 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, NULL, "%s", msg);
234 exit(APEXIT_CHILDFATAL);
239 /* On some architectures it's safe to do unserialized accept()s in the single
240 * Listen case. But it's never safe to do it in the case where there's
241 * multiple Listen statements. Define SINGLE_LISTEN_UNSERIALIZED_ACCEPT
242 * when it's safe in the single Listen case.
244 #ifdef SINGLE_LISTEN_UNSERIALIZED_ACCEPT
245 #define SAFE_ACCEPT(stmt) do {if (ap_listeners->next) {stmt;}} while(0)
247 #define SAFE_ACCEPT(stmt) do {stmt;} while(0)
250 AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result)
253 case AP_MPMQ_MAX_DAEMON_USED:
254 *result = ap_daemons_limit;
256 case AP_MPMQ_IS_THREADED:
257 *result = AP_MPMQ_NOT_SUPPORTED;
259 case AP_MPMQ_IS_FORKED:
260 *result = AP_MPMQ_DYNAMIC;
262 case AP_MPMQ_HARD_LIMIT_DAEMONS:
263 *result = server_limit;
265 case AP_MPMQ_HARD_LIMIT_THREADS:
266 *result = HARD_THREAD_LIMIT;
268 case AP_MPMQ_MAX_THREADS:
271 case AP_MPMQ_MIN_SPARE_DAEMONS:
272 *result = ap_daemons_min_free;
274 case AP_MPMQ_MIN_SPARE_THREADS:
277 case AP_MPMQ_MAX_SPARE_DAEMONS:
278 *result = ap_daemons_max_free;
280 case AP_MPMQ_MAX_SPARE_THREADS:
283 case AP_MPMQ_MAX_REQUESTS_DAEMON:
284 *result = ap_max_requests_per_child;
286 case AP_MPMQ_MAX_DAEMONS:
287 *result = server_limit;
289 case AP_MPMQ_MPM_STATE:
296 /*****************************************************************
297 * Connection structures and accounting...
300 static void just_die(int sig)
305 static void stop_listening(int sig)
307 ap_close_listeners();
309 /* For a graceful stop, we want the child to exit when done */
313 /* volatile just in case */
314 static int volatile shutdown_pending;
315 static int volatile restart_pending;
316 static int volatile is_graceful;
318 static void sig_term(int sig)
320 if (shutdown_pending == 1) {
321 /* Um, is this _probably_ not an error, if the user has
322 * tried to do a shutdown twice quickly, so we won't
323 * worry about reporting it.
327 shutdown_pending = 1;
328 is_graceful = (sig == AP_SIG_GRACEFUL_STOP);
331 /* restart() is the signal handler for SIGHUP and AP_SIG_GRACEFUL
332 * in the parent process, unless running in ONE_PROCESS mode
334 static void restart(int sig)
336 if (restart_pending == 1) {
337 /* Probably not an error - don't bother reporting it */
341 is_graceful = (sig == AP_SIG_GRACEFUL);
344 static void set_signals(void)
346 #ifndef NO_USE_SIGACTION
351 ap_fatal_signal_setup(ap_server_conf, pconf);
354 #ifndef NO_USE_SIGACTION
355 sigemptyset(&sa.sa_mask);
358 sa.sa_handler = sig_term;
359 if (sigaction(SIGTERM, &sa, NULL) < 0)
360 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGTERM)");
361 #ifdef AP_SIG_GRACEFUL_STOP
362 if (sigaction(AP_SIG_GRACEFUL_STOP, &sa, NULL) < 0)
363 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
364 "sigaction(" AP_SIG_GRACEFUL_STOP_STRING ")");
367 if (sigaction(SIGINT, &sa, NULL) < 0)
368 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGINT)");
371 sa.sa_handler = SIG_DFL;
372 if (sigaction(SIGXCPU, &sa, NULL) < 0)
373 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGXCPU)");
376 sa.sa_handler = SIG_DFL;
377 if (sigaction(SIGXFSZ, &sa, NULL) < 0)
378 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGXFSZ)");
381 sa.sa_handler = SIG_IGN;
382 if (sigaction(SIGPIPE, &sa, NULL) < 0)
383 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGPIPE)");
386 /* we want to ignore HUPs and AP_SIG_GRACEFUL while we're busy
389 sigaddset(&sa.sa_mask, SIGHUP);
390 sigaddset(&sa.sa_mask, AP_SIG_GRACEFUL);
391 sa.sa_handler = restart;
392 if (sigaction(SIGHUP, &sa, NULL) < 0)
393 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGHUP)");
394 if (sigaction(AP_SIG_GRACEFUL, &sa, NULL) < 0)
395 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(" AP_SIG_GRACEFUL_STRING ")");
399 apr_signal(SIGXCPU, SIG_DFL);
402 apr_signal(SIGXFSZ, SIG_DFL);
406 apr_signal(SIGTERM, sig_term);
408 apr_signal(SIGHUP, restart);
410 #ifdef AP_SIG_GRACEFUL
411 apr_signal(AP_SIG_GRACEFUL, restart);
412 #endif /* AP_SIG_GRACEFUL */
413 #ifdef AP_SIG_GRACEFUL_STOP
414 apr_signal(AP_SIG_GRACEFUL_STOP, sig_term);
415 #endif /* AP_SIG_GRACEFUL */
417 apr_signal(SIGPIPE, SIG_IGN);
423 /*****************************************************************
424 * Child process main loop.
425 * The following vars are static to avoid getting clobbered by longjmp();
426 * they are really private to child_main.
429 static int requests_this_child;
430 static int num_listensocks = 0;
432 static void child_main(int child_num_arg)
435 apr_allocator_t *allocator;
439 apr_pollset_t *pollset;
441 apr_bucket_alloc_t *bucket_alloc;
442 int last_poll_idx = 0;
444 mpm_state = AP_MPMQ_STARTING; /* for benefit of any hooks that run as this
448 my_child_num = child_num_arg;
449 ap_my_pid = getpid();
450 requests_this_child = 0;
452 ap_fatal_signal_child_setup(ap_server_conf);
454 /* Get a sub context for global allocations in this child, so that
455 * we can have cleanups occur when the child exits.
457 apr_allocator_create(&allocator);
458 apr_allocator_max_free_set(allocator, ap_max_mem_free);
459 apr_pool_create_ex(&pchild, pconf, NULL, allocator);
460 apr_allocator_owner_set(allocator, pchild);
461 apr_pool_tag(pchild, "pchild");
463 apr_pool_create(&ptrans, pchild);
464 apr_pool_tag(ptrans, "transaction");
466 /* needs to be done before we switch UIDs so we have permissions */
467 ap_reopen_scoreboard(pchild, NULL, 0);
468 status = apr_proc_mutex_child_init(&accept_mutex, ap_lock_fname, pchild);
469 if (status != APR_SUCCESS) {
470 ap_log_error(APLOG_MARK, APLOG_EMERG, status, ap_server_conf,
471 "Couldn't initialize cross-process lock in child "
472 "(%s) (%d)", ap_lock_fname, ap_accept_lock_mech);
473 clean_child_exit(APEXIT_CHILDFATAL);
476 if (ap_run_drop_privileges(pchild, ap_server_conf)) {
477 clean_child_exit(APEXIT_CHILDFATAL);
480 ap_run_child_init(pchild, ap_server_conf);
482 ap_create_sb_handle(&sbh, pchild, my_child_num, 0);
484 (void) ap_update_child_status(sbh, SERVER_READY, (request_rec *) NULL);
486 /* Set up the pollfd array */
487 /* ### check the status */
488 (void) apr_pollset_create(&pollset, num_listensocks, pchild, 0);
490 for (lr = ap_listeners, i = num_listensocks; i--; lr = lr->next) {
491 apr_pollfd_t pfd = { 0 };
493 pfd.desc_type = APR_POLL_SOCKET;
495 pfd.reqevents = APR_POLLIN;
496 pfd.client_data = lr;
498 /* ### check the status */
499 (void) apr_pollset_add(pollset, &pfd);
502 mpm_state = AP_MPMQ_RUNNING;
504 bucket_alloc = apr_bucket_alloc_create(pchild);
506 /* die_now is set when AP_SIG_GRACEFUL is received in the child;
507 * shutdown_pending is set when SIGTERM is received when running
508 * in single process mode. */
509 while (!die_now && !shutdown_pending) {
510 conn_rec *current_conn;
514 * (Re)initialize this child to a pre-connection state.
517 apr_pool_clear(ptrans);
519 if ((ap_max_requests_per_child > 0
520 && requests_this_child++ >= ap_max_requests_per_child)) {
524 (void) ap_update_child_status(sbh, SERVER_READY, (request_rec *) NULL);
527 * Wait for an acceptable connection to arrive.
530 /* Lock around "accept", if necessary */
531 SAFE_ACCEPT(accept_mutex_on());
533 if (num_listensocks == 1) {
534 /* There is only one listener record, so refer to that one. */
538 /* multiple listening sockets - need to poll */
541 const apr_pollfd_t *pdesc;
543 /* timeout == -1 == wait forever */
544 status = apr_pollset_poll(pollset, -1, &numdesc, &pdesc);
545 if (status != APR_SUCCESS) {
546 if (APR_STATUS_IS_EINTR(status)) {
547 if (one_process && shutdown_pending) {
551 /* In graceful stop/restart; drop the mutex
552 * and terminate the child. */
553 SAFE_ACCEPT(accept_mutex_off());
558 /* Single Unix documents select as returning errnos
559 * EBADF, EINTR, and EINVAL... and in none of those
560 * cases does it make sense to continue. In fact
561 * on Linux 2.0.x we seem to end up with EFAULT
562 * occasionally, and we'd loop forever due to it.
564 ap_log_error(APLOG_MARK, APLOG_ERR, status,
565 ap_server_conf, "apr_pollset_poll: (listen)");
566 SAFE_ACCEPT(accept_mutex_off());
570 /* We can always use pdesc[0], but sockets at position N
571 * could end up completely starved of attention in a very
572 * busy server. Therefore, we round-robin across the
573 * returned set of descriptors. While it is possible that
574 * the returned set of descriptors might flip around and
575 * continue to starve some sockets, we happen to know the
576 * internal pollset implementation retains ordering
577 * stability of the sockets. Thus, the round-robin should
578 * ensure that a socket will eventually be serviced.
580 if (last_poll_idx >= numdesc)
583 /* Grab a listener record from the client_data of the poll
584 * descriptor, and advance our saved index to round-robin
587 * ### hmm... this descriptor might have POLLERR rather
590 lr = pdesc[last_poll_idx++].client_data;
595 /* if we accept() something we don't want to die, so we have to
598 status = lr->accept_func(&csd, lr, ptrans);
600 SAFE_ACCEPT(accept_mutex_off()); /* unlock after "accept" */
602 if (status == APR_EGENERAL) {
603 /* resource shortage or should-not-occur occured */
606 else if (status != APR_SUCCESS) {
611 * We now have a connection, so set it up with the appropriate
612 * socket options, file descriptors, and read/write buffers.
615 current_conn = ap_run_create_connection(ptrans, ap_server_conf, csd, my_child_num, sbh, bucket_alloc);
617 ap_process_connection(current_conn, csd);
618 ap_lingering_close(current_conn);
621 /* Check the pod and the generation number after processing a
622 * connection so that we'll go away if a graceful restart occurred
623 * while we were processing the connection or we are the lucky
624 * idle server process that gets to die.
626 if (ap_mpm_pod_check(pod) == APR_SUCCESS) { /* selected as idle? */
629 else if (ap_my_generation !=
630 ap_scoreboard_image->global->running_generation) { /* restart? */
631 /* yeah, this could be non-graceful restart, in which case the
632 * parent will kill us soon enough, but why bother checking?
641 static int make_child(server_rec *s, int slot)
645 if (slot + 1 > ap_max_daemons_limit) {
646 ap_max_daemons_limit = slot + 1;
650 apr_signal(SIGHUP, sig_term);
651 /* Don't catch AP_SIG_GRACEFUL in ONE_PROCESS mode :) */
652 apr_signal(SIGINT, sig_term);
654 apr_signal(SIGQUIT, SIG_DFL);
656 apr_signal(SIGTERM, sig_term);
661 (void) ap_update_child_status_from_indexes(slot, 0, SERVER_STARTING,
662 (request_rec *) NULL);
666 /* BS2000 requires a "special" version of fork() before a setuid() call */
667 if ((pid = os_fork(unixd_config.user_name)) == -1) {
669 if ((pid = os_fork(s, slot)) == -1) {
671 if ((pid = fork()) == -1) {
673 ap_log_error(APLOG_MARK, APLOG_ERR, errno, s, "fork: Unable to fork new process");
675 /* fork didn't succeed. Fix the scoreboard or else
676 * it will say SERVER_STARTING forever and ever
678 (void) ap_update_child_status_from_indexes(slot, 0, SERVER_DEAD,
679 (request_rec *) NULL);
681 /* In case system resources are maxxed out, we don't want
682 * Apache running away with the CPU trying to fork over and
683 * over and over again.
691 #ifdef HAVE_BINDPROCESSOR
692 /* by default AIX binds to a single processor
693 * this bit unbinds children which will then bind to another cpu
695 int status = bindprocessor(BINDPROCESS, (int)getpid(),
696 PROCESSOR_CLASS_ANY);
698 ap_log_error(APLOG_MARK, APLOG_WARNING, errno,
699 ap_server_conf, "processor unbind failed %d", status);
702 RAISE_SIGSTOP(MAKE_CHILD);
704 /* Disable the parent's signal handlers and set up proper handling in
707 apr_signal(SIGHUP, just_die);
708 apr_signal(SIGTERM, just_die);
709 /* The child process just closes listeners on AP_SIG_GRACEFUL.
710 * The pod is used for signalling the graceful restart.
712 apr_signal(AP_SIG_GRACEFUL, stop_listening);
716 ap_scoreboard_image->parent[slot].pid = pid;
722 /* start up a bunch of children */
723 static void startup_children(int number_to_start)
727 for (i = 0; number_to_start && i < ap_daemons_limit; ++i) {
728 if (ap_scoreboard_image->servers[i][0].status != SERVER_DEAD) {
731 if (make_child(ap_server_conf, i) < 0) {
740 * idle_spawn_rate is the number of children that will be spawned on the
741 * next maintenance cycle if there aren't enough idle servers. It is
742 * doubled up to MAX_SPAWN_RATE, and reset only when a cycle goes by
743 * without the need to spawn.
745 static int idle_spawn_rate = 1;
746 #ifndef MAX_SPAWN_RATE
747 #define MAX_SPAWN_RATE (32)
749 static int hold_off_on_exponential_spawning;
751 static void perform_idle_server_maintenance(apr_pool_t *p)
758 int free_slots[MAX_SPAWN_RATE];
762 /* initialize the free_list */
770 for (i = 0; i < ap_daemons_limit; ++i) {
773 if (i >= ap_max_daemons_limit && free_length == idle_spawn_rate)
775 ws = &ap_scoreboard_image->servers[i][0];
777 if (status == SERVER_DEAD) {
778 /* try to keep children numbers as low as possible */
779 if (free_length < idle_spawn_rate) {
780 free_slots[free_length] = i;
785 /* We consider a starting server as idle because we started it
786 * at least a cycle ago, and if it still hasn't finished starting
787 * then we're just going to swamp things worse by forking more.
788 * So we hopefully won't need to fork more if we count it.
789 * This depends on the ordering of SERVER_READY and SERVER_STARTING.
791 if (status <= SERVER_READY) {
793 /* always kill the highest numbered child if we have to...
794 * no really well thought out reason ... other than observing
795 * the server behaviour under linux where lower numbered children
796 * tend to service more hits (and hence are more likely to have
797 * their data in cpu caches).
806 ap_max_daemons_limit = last_non_dead + 1;
807 if (idle_count > ap_daemons_max_free) {
808 /* kill off one child... we use the pod because that'll cause it to
809 * shut down gracefully, in case it happened to pick up a request
810 * while we were counting
812 ap_mpm_pod_signal(pod);
815 else if (idle_count < ap_daemons_min_free) {
816 /* terminate the free list */
817 if (free_length == 0) {
818 /* only report this condition once */
819 static int reported = 0;
822 ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf,
823 "server reached MaxClients setting, consider"
824 " raising the MaxClients setting");
830 if (idle_spawn_rate >= 8) {
831 ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf,
832 "server seems busy, (you may need "
833 "to increase StartServers, or Min/MaxSpareServers), "
834 "spawning %d children, there are %d idle, and "
835 "%d total children", idle_spawn_rate,
836 idle_count, total_non_dead);
838 for (i = 0; i < free_length; ++i) {
840 if (make_child(ap_server_conf, free_slots[i]) == -1) {
841 if(free_length == 1) {
842 shutdown_pending = 1;
843 ap_log_error(APLOG_MARK, APLOG_EMERG, 0, ap_server_conf,
844 "No active child processes: shutting down");
848 make_child(ap_server_conf, free_slots[i]);
851 /* the next time around we want to spawn twice as many if this
852 * wasn't good enough, but not if we've just done a graceful
854 if (hold_off_on_exponential_spawning) {
855 --hold_off_on_exponential_spawning;
857 else if (idle_spawn_rate < MAX_SPAWN_RATE) {
858 idle_spawn_rate *= 2;
867 /*****************************************************************
868 * Executive routines.
871 int ap_mpm_run(apr_pool_t *_pconf, apr_pool_t *plog, server_rec *s)
874 int remaining_children_to_start;
877 ap_log_pid(pconf, ap_pid_fname);
879 /* Initialize cross-process accept lock */
880 ap_lock_fname = apr_psprintf(_pconf, "%s.%" APR_PID_T_FMT,
881 ap_server_root_relative(_pconf, ap_lock_fname),
884 rv = apr_proc_mutex_create(&accept_mutex, ap_lock_fname,
885 ap_accept_lock_mech, _pconf);
886 if (rv != APR_SUCCESS) {
887 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
888 "Couldn't create accept lock (%s) (%d)",
889 ap_lock_fname, ap_accept_lock_mech);
890 mpm_state = AP_MPMQ_STOPPING;
894 #if APR_USE_SYSVSEM_SERIALIZE
895 if (ap_accept_lock_mech == APR_LOCK_DEFAULT ||
896 ap_accept_lock_mech == APR_LOCK_SYSVSEM) {
898 if (ap_accept_lock_mech == APR_LOCK_SYSVSEM) {
900 rv = unixd_set_proc_mutex_perms(accept_mutex);
901 if (rv != APR_SUCCESS) {
902 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
903 "Couldn't set permissions on cross-process lock; "
904 "check User and Group directives");
905 mpm_state = AP_MPMQ_STOPPING;
911 if (ap_run_pre_mpm(s->process->pool, SB_SHARED) != OK) {
912 mpm_state = AP_MPMQ_STOPPING;
915 /* fix the generation number in the global score; we just got a new,
918 ap_scoreboard_image->global->running_generation = ap_my_generation;
925 make_child(ap_server_conf, 0);
928 if (ap_daemons_max_free < ap_daemons_min_free + 1) /* Don't thrash... */
929 ap_daemons_max_free = ap_daemons_min_free + 1;
931 /* If we're doing a graceful_restart then we're going to see a lot
932 * of children exiting immediately when we get into the main loop
933 * below (because we just sent them AP_SIG_GRACEFUL). This happens pretty
934 * rapidly... and for each one that exits we'll start a new one until
935 * we reach at least daemons_min_free. But we may be permitted to
936 * start more than that, so we'll just keep track of how many we're
937 * supposed to start up without the 1 second penalty between each fork.
939 remaining_children_to_start = ap_daemons_to_start;
940 if (remaining_children_to_start > ap_daemons_limit) {
941 remaining_children_to_start = ap_daemons_limit;
944 startup_children(remaining_children_to_start);
945 remaining_children_to_start = 0;
948 /* give the system some time to recover before kicking into
951 hold_off_on_exponential_spawning = 10;
954 ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
955 "%s configured -- resuming normal operations",
956 ap_get_server_description());
957 ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf,
958 "Server built: %s", ap_get_server_built());
959 #ifdef AP_MPM_WANT_SET_ACCEPT_LOCK_MECH
960 ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
961 "AcceptMutex: %s (default: %s)",
962 apr_proc_mutex_name(accept_mutex),
963 apr_proc_mutex_defname());
965 restart_pending = shutdown_pending = 0;
967 mpm_state = AP_MPMQ_RUNNING;
969 while (!restart_pending && !shutdown_pending) {
971 apr_exit_why_e exitwhy;
972 int status, processed_status;
973 /* this is a memory leak, but I'll fix it later. */
976 ap_wait_or_timeout(&exitwhy, &status, &pid, pconf);
978 /* XXX: if it takes longer than 1 second for all our children
979 * to start up and get into IDLE state then we may spawn an
983 processed_status = ap_process_child_status(&pid, exitwhy, status);
984 if (processed_status == APEXIT_CHILDFATAL) {
985 mpm_state = AP_MPMQ_STOPPING;
989 /* non-fatal death... note that it's gone in the scoreboard. */
990 child_slot = find_child_by_pid(&pid);
991 if (child_slot >= 0) {
992 (void) ap_update_child_status_from_indexes(child_slot, 0, SERVER_DEAD,
993 (request_rec *) NULL);
994 if (processed_status == APEXIT_CHILDSICK) {
995 /* child detected a resource shortage (E[NM]FILE, ENOBUFS, etc)
996 * cut the fork rate to the minimum
1000 else if (remaining_children_to_start
1001 && child_slot < ap_daemons_limit) {
1002 /* we're still doing a 1-for-1 replacement of dead
1003 * children with new children
1005 make_child(ap_server_conf, child_slot);
1006 --remaining_children_to_start;
1008 #if APR_HAS_OTHER_CHILD
1010 else if (apr_proc_other_child_alert(&pid, APR_OC_REASON_DEATH, status) == APR_SUCCESS) {
1014 else if (is_graceful) {
1015 /* Great, we've probably just lost a slot in the
1016 * scoreboard. Somehow we don't know about this
1019 ap_log_error(APLOG_MARK, APLOG_WARNING,
1021 "long lost child came home! (pid %ld)", (long)pid.pid);
1023 /* Don't perform idle maintenance when a child dies,
1024 * only do it when there's a timeout. Remember only a
1025 * finite number of children can die, and it's pretty
1026 * pathological for a lot to die suddenly.
1030 else if (remaining_children_to_start) {
1031 /* we hit a 1 second timeout in which none of the previous
1032 * generation of children needed to be reaped... so assume
1033 * they're all done, and pick up the slack if any is left.
1035 startup_children(remaining_children_to_start);
1036 remaining_children_to_start = 0;
1037 /* In any event we really shouldn't do the code below because
1038 * few of the servers we just started are in the IDLE state
1039 * yet, so we'd mistakenly create an extra server.
1044 perform_idle_server_maintenance(pconf);
1046 shutdown_pending = os_check_server(tpf_server_name);
1053 mpm_state = AP_MPMQ_STOPPING;
1055 if (shutdown_pending && !is_graceful) {
1056 /* Time to shut down:
1057 * Kill child processes, tell them to call child_exit, etc...
1059 if (unixd_killpg(getpgrp(), SIGTERM) < 0) {
1060 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "killpg SIGTERM");
1062 ap_reclaim_child_processes(1); /* Start with SIGTERM */
1064 /* cleanup pid file on normal shutdown */
1066 const char *pidfile = NULL;
1067 pidfile = ap_server_root_relative (pconf, ap_pid_fname);
1068 if ( pidfile != NULL && unlink(pidfile) == 0)
1069 ap_log_error(APLOG_MARK, APLOG_INFO,
1071 "removed PID file %s (pid=%ld)",
1072 pidfile, (long)getpid());
1075 ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
1076 "caught SIGTERM, shutting down");
1079 } else if (shutdown_pending) {
1080 /* Time to perform a graceful shut down:
1081 * Reap the inactive children, and ask the active ones
1082 * to close their listeners, then wait until they are
1085 int active_children;
1086 apr_time_t cutoff = 0;
1088 /* Stop listening */
1089 ap_close_listeners();
1091 /* kill off the idle ones */
1092 ap_mpm_pod_killpg(pod, ap_max_daemons_limit);
1094 /* Send SIGUSR1 to the active children */
1095 active_children = 0;
1096 for (index = 0; index < ap_daemons_limit; ++index) {
1097 if (ap_scoreboard_image->servers[index][0].status != SERVER_DEAD) {
1098 /* Ask each child to close its listeners. */
1099 ap_mpm_safe_kill(MPM_CHILD_PID(index), AP_SIG_GRACEFUL);
1104 /* Allow each child which actually finished to exit */
1105 ap_relieve_child_processes();
1107 /* cleanup pid file */
1109 const char *pidfile = NULL;
1110 pidfile = ap_server_root_relative (pconf, ap_pid_fname);
1111 if ( pidfile != NULL && unlink(pidfile) == 0)
1112 ap_log_error(APLOG_MARK, APLOG_INFO,
1114 "removed PID file %s (pid=%ld)",
1115 pidfile, (long)getpid());
1118 ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
1119 "caught " AP_SIG_GRACEFUL_STOP_STRING ", shutting down gracefully");
1121 if (ap_graceful_shutdown_timeout) {
1122 cutoff = apr_time_now() +
1123 apr_time_from_sec(ap_graceful_shutdown_timeout);
1126 /* Don't really exit until each child has finished */
1127 shutdown_pending = 0;
1129 /* Pause for a second */
1132 /* Relieve any children which have now exited */
1133 ap_relieve_child_processes();
1135 active_children = 0;
1136 for (index = 0; index < ap_daemons_limit; ++index) {
1137 if (ap_mpm_safe_kill(MPM_CHILD_PID(index), 0) == APR_SUCCESS) {
1138 active_children = 1;
1139 /* Having just one child is enough to stay around */
1143 } while (!shutdown_pending && active_children &&
1144 (!ap_graceful_shutdown_timeout || apr_time_now() < cutoff));
1146 /* We might be here because we received SIGTERM, either
1147 * way, try and make sure that all of our processes are
1150 unixd_killpg(getpgrp(), SIGTERM);
1155 /* we've been told to restart */
1156 apr_signal(SIGHUP, SIG_IGN);
1157 apr_signal(AP_SIG_GRACEFUL, SIG_IGN);
1159 /* not worth thinking about */
1163 /* advance to the next generation */
1164 /* XXX: we really need to make sure this new generation number isn't in
1165 * use by any of the children.
1168 ap_scoreboard_image->global->running_generation = ap_my_generation;
1171 ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
1172 "Graceful restart requested, doing restart");
1174 /* kill off the idle ones */
1175 ap_mpm_pod_killpg(pod, ap_max_daemons_limit);
1177 /* This is mostly for debugging... so that we know what is still
1178 * gracefully dealing with existing request. This will break
1179 * in a very nasty way if we ever have the scoreboard totally
1180 * file-based (no shared memory)
1182 for (index = 0; index < ap_daemons_limit; ++index) {
1183 if (ap_scoreboard_image->servers[index][0].status != SERVER_DEAD) {
1184 ap_scoreboard_image->servers[index][0].status = SERVER_GRACEFUL;
1185 /* Ask each child to close its listeners.
1187 * NOTE: we use the scoreboard, because if we send SIGUSR1
1188 * to every process in the group, this may include CGI's,
1189 * piped loggers, etc. They almost certainly won't handle
1192 ap_mpm_safe_kill(ap_scoreboard_image->parent[index].pid, AP_SIG_GRACEFUL);
1198 if (unixd_killpg(getpgrp(), SIGHUP) < 0) {
1199 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "killpg SIGHUP");
1201 ap_reclaim_child_processes(0); /* Not when just starting up */
1202 ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
1203 "SIGHUP received. Attempting to restart");
1209 /* This really should be a post_config hook, but the error log is already
1210 * redirected by that point, so we need to do this in the open_logs phase.
1212 static int prefork_open_logs(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s)
1214 static int restart_num = 0;
1216 int level_flags = 0;
1222 /* the reverse of pre_config, we want this only the first time around */
1223 if (restart_num++ == 0) {
1225 level_flags |= APLOG_STARTUP;
1228 if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) {
1229 ap_log_error(APLOG_MARK, APLOG_ALERT | level_flags, 0,
1230 (startup ? NULL : s),
1231 "no listening sockets available, shutting down");
1235 if ((rv = ap_mpm_pod_open(pconf, &pod))) {
1236 ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv,
1237 (startup ? NULL : s),
1238 "could not open pipe-of-death");
1244 static int prefork_pre_config(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp)
1246 static int restart_num = 0;
1247 int no_detach, debug, foreground;
1250 mpm_state = AP_MPMQ_STARTING;
1252 debug = ap_exists_config_define("DEBUG");
1255 foreground = one_process = 1;
1260 no_detach = ap_exists_config_define("NO_DETACH");
1261 one_process = ap_exists_config_define("ONE_PROCESS");
1262 foreground = ap_exists_config_define("FOREGROUND");
1265 /* sigh, want this only the second time around */
1266 if (restart_num++ == 1) {
1269 if (!one_process && !foreground) {
1270 rv = apr_proc_detach(no_detach ? APR_PROC_DETACH_FOREGROUND
1271 : APR_PROC_DETACH_DAEMONIZE);
1272 if (rv != APR_SUCCESS) {
1273 ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL,
1274 "apr_proc_detach failed");
1275 return HTTP_INTERNAL_SERVER_ERROR;
1279 parent_pid = ap_my_pid = getpid();
1282 unixd_pre_config(ptemp);
1283 ap_listen_pre_config();
1284 ap_daemons_to_start = DEFAULT_START_DAEMON;
1285 ap_daemons_min_free = DEFAULT_MIN_FREE_DAEMON;
1286 ap_daemons_max_free = DEFAULT_MAX_FREE_DAEMON;
1287 server_limit = DEFAULT_SERVER_LIMIT;
1288 ap_daemons_limit = server_limit;
1289 ap_pid_fname = DEFAULT_PIDLOG;
1290 ap_lock_fname = DEFAULT_LOCKFILE;
1291 ap_max_requests_per_child = DEFAULT_MAX_REQUESTS_PER_CHILD;
1292 ap_extended_status = 0;
1293 #ifdef AP_MPM_WANT_SET_MAX_MEM_FREE
1294 ap_max_mem_free = APR_ALLOCATOR_MAX_FREE_UNLIMITED;
1297 apr_cpystrn(ap_coredump_dir, ap_server_root, sizeof(ap_coredump_dir));
1302 static int prefork_check_config(apr_pool_t *p, apr_pool_t *plog,
1303 apr_pool_t *ptemp, server_rec *s)
1305 static int restart_num = 0;
1308 /* the reverse of pre_config, we want this only the first time around */
1309 if (restart_num++ == 0) {
1313 if (server_limit > MAX_SERVER_LIMIT) {
1315 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1316 "WARNING: ServerLimit of %d exceeds compile-time "
1317 "limit of", server_limit);
1318 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1319 " %d servers, decreasing to %d.",
1320 MAX_SERVER_LIMIT, MAX_SERVER_LIMIT);
1322 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1323 "ServerLimit of %d exceeds compile-time limit "
1324 "of %d, decreasing to match",
1325 server_limit, MAX_SERVER_LIMIT);
1327 server_limit = MAX_SERVER_LIMIT;
1329 else if (server_limit < 1) {
1331 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1332 "WARNING: ServerLimit of %d not allowed, "
1333 "increasing to 1.", server_limit);
1335 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1336 "ServerLimit of %d not allowed, increasing to 1",
1342 /* you cannot change ServerLimit across a restart; ignore
1345 if (!first_server_limit) {
1346 first_server_limit = server_limit;
1348 else if (server_limit != first_server_limit) {
1349 /* don't need a startup console version here */
1350 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1351 "changing ServerLimit to %d from original value of %d "
1352 "not allowed during restart",
1353 server_limit, first_server_limit);
1354 server_limit = first_server_limit;
1357 if (ap_daemons_limit > server_limit) {
1359 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1360 "WARNING: MaxClients of %d exceeds ServerLimit "
1361 "value of", ap_daemons_limit);
1362 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1363 " %d servers, decreasing MaxClients to %d.",
1364 server_limit, server_limit);
1365 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1366 " To increase, please see the ServerLimit "
1369 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1370 "MaxClients of %d exceeds ServerLimit value "
1371 "of %d, decreasing to match",
1372 ap_daemons_limit, server_limit);
1374 ap_daemons_limit = server_limit;
1376 else if (ap_daemons_limit < 1) {
1378 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1379 "WARNING: MaxClients of %d not allowed, "
1380 "increasing to 1.", ap_daemons_limit);
1382 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1383 "MaxClients of %d not allowed, increasing to 1",
1386 ap_daemons_limit = 1;
1389 /* ap_daemons_to_start > ap_daemons_limit checked in ap_mpm_run() */
1390 if (ap_daemons_to_start < 0) {
1392 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1393 "WARNING: StartServers of %d not allowed, "
1394 "increasing to 1.", ap_daemons_to_start);
1396 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1397 "StartServers of %d not allowed, increasing to 1",
1398 ap_daemons_to_start);
1400 ap_daemons_to_start = 1;
1403 if (ap_daemons_min_free < 1) {
1405 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1406 "WARNING: MinSpareServers of %d not allowed, "
1407 "increasing to 1", ap_daemons_min_free);
1408 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1409 " to avoid almost certain server failure.");
1410 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL,
1411 " Please read the documentation.");
1413 ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
1414 "MinSpareServers of %d not allowed, increasing to 1",
1415 ap_daemons_min_free);
1417 ap_daemons_min_free = 1;
1420 /* ap_daemons_max_free < ap_daemons_min_free + 1 checked in ap_mpm_run() */
1425 static void prefork_hooks(apr_pool_t *p)
1427 /* Our open_logs hook function must run before the core's, or stderr
1428 * will be redirected to a file, and the messages won't print to the
1431 static const char *const aszSucc[] = {"core.c", NULL};
1437 ap_hook_open_logs(prefork_open_logs, NULL, aszSucc, APR_HOOK_REALLY_FIRST);
1438 /* we need to set the MPM state before other pre-config hooks use MPM query
1439 * to retrieve it, so register as REALLY_FIRST
1441 ap_hook_pre_config(prefork_pre_config, NULL, NULL, APR_HOOK_REALLY_FIRST);
1442 ap_hook_check_config(prefork_check_config, NULL, NULL, APR_HOOK_MIDDLE);
1445 static const char *set_daemons_to_start(cmd_parms *cmd, void *dummy, const char *arg)
1447 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1452 ap_daemons_to_start = atoi(arg);
1456 static const char *set_min_free_servers(cmd_parms *cmd, void *dummy, const char *arg)
1458 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1463 ap_daemons_min_free = atoi(arg);
1467 static const char *set_max_free_servers(cmd_parms *cmd, void *dummy, const char *arg)
1469 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1474 ap_daemons_max_free = atoi(arg);
1478 static const char *set_max_clients (cmd_parms *cmd, void *dummy, const char *arg)
1480 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1485 ap_daemons_limit = atoi(arg);
1489 static const char *set_server_limit (cmd_parms *cmd, void *dummy, const char *arg)
1491 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1496 server_limit = atoi(arg);
1500 static const command_rec prefork_cmds[] = {
1501 UNIX_DAEMON_COMMANDS,
1503 AP_INIT_TAKE1("StartServers", set_daemons_to_start, NULL, RSRC_CONF,
1504 "Number of child processes launched at server startup"),
1505 AP_INIT_TAKE1("MinSpareServers", set_min_free_servers, NULL, RSRC_CONF,
1506 "Minimum number of idle children, to handle request spikes"),
1507 AP_INIT_TAKE1("MaxSpareServers", set_max_free_servers, NULL, RSRC_CONF,
1508 "Maximum number of idle children"),
1509 AP_INIT_TAKE1("MaxClients", set_max_clients, NULL, RSRC_CONF,
1510 "Maximum number of children alive at the same time"),
1511 AP_INIT_TAKE1("ServerLimit", set_server_limit, NULL, RSRC_CONF,
1512 "Maximum value of MaxClients for this run of Apache"),
1513 AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND,
1517 module AP_MODULE_DECLARE_DATA mpm_prefork_module = {
1519 ap_mpm_rewrite_args, /* hook to run before apache parses args */
1520 NULL, /* create per-directory config structure */
1521 NULL, /* merge per-directory config structures */
1522 NULL, /* create per-server config structure */
1523 NULL, /* merge per-server config structures */
1524 prefork_cmds, /* command apr_table_t */
1525 prefork_hooks, /* register hooks */