1 /* ====================================================================
2 * The Apache Software License, Version 1.1
4 * Copyright (c) 2000-2002 The Apache Software Foundation. All rights
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in
16 * the documentation and/or other materials provided with the
19 * 3. The end-user documentation included with the redistribution,
20 * if any, must include the following acknowledgment:
21 * "This product includes software developed by the
22 * Apache Software Foundation (http://www.apache.org/)."
23 * Alternately, this acknowledgment may appear in the software itself,
24 * if and wherever such third-party acknowledgments normally appear.
26 * 4. The names "Apache" and "Apache Software Foundation" must
27 * not be used to endorse or promote products derived from this
28 * software without prior written permission. For written
29 * permission, please contact apache@apache.org.
31 * 5. Products derived from this software may not be called "Apache",
32 * nor may "Apache" appear in their name, without prior written
33 * permission of the Apache Software Foundation.
35 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
36 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
37 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
38 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
41 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
42 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
43 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
44 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
45 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
47 * ====================================================================
49 * This software consists of voluntary contributions made by many
50 * individuals on behalf of the Apache Software Foundation. For more
51 * information on the Apache Software Foundation, please see
52 * <http://www.apache.org/>.
54 * Portions of this software are based upon public domain software
55 * originally written at the National Center for Supercomputing Applications,
56 * University of Illinois, Urbana-Champaign.
59 /* The purpose of this MPM is to fix the design flaws in the threaded
60 * model. Because of the way that pthreads and mutex locks interact,
61 * it is basically impossible to cleanly gracefully shutdown a child
62 * process if multiple threads are all blocked in accept. This model
63 * fixes those problems.
67 #include "apr_portable.h"
68 #include "apr_strings.h"
69 #include "apr_file_io.h"
70 #include "apr_thread_proc.h"
71 #include "apr_signal.h"
72 #include "apr_thread_mutex.h"
73 #include "apr_proc_mutex.h"
74 #define APR_WANT_STRFUNC
80 #if APR_HAVE_SYS_SOCKET_H
81 #include <sys/socket.h>
83 #if APR_HAVE_SYS_WAIT_H
86 #ifdef HAVE_SYS_PROCESSOR_H
87 #include <sys/processor.h> /* for bindprocessor() */
91 #error The Worker MPM requires APR threads, but they are unavailable.
96 #include "ap_config.h"
98 #include "http_main.h"
100 #include "http_config.h" /* for read_config */
101 #include "http_core.h" /* for get_remote_host */
102 #include "http_connection.h"
105 #include "mpm_common.h"
106 #include "ap_listen.h"
107 #include "scoreboard.h"
109 #include "mpm_default.h"
112 #include <limits.h> /* for INT_MAX */
114 /* Limit on the total --- clients will be locked out if more servers than
115 * this are needed. It is intended solely to keep the server from crashing
116 * when things get out of hand.
118 * We keep a hard maximum number of servers, for two reasons --- first off,
119 * in case something goes seriously wrong, we want to stop the fork bomb
120 * short of actually crashing the machine we're running on by filling some
121 * kernel table. Secondly, it keeps the size of the scoreboard file small
122 * enough that we can read the whole thing without worrying too much about
125 #ifndef DEFAULT_SERVER_LIMIT
126 #define DEFAULT_SERVER_LIMIT 16
129 /* Admin can't tune ServerLimit beyond MAX_SERVER_LIMIT. We want
130 * some sort of compile-time limit to help catch typos.
132 #ifndef MAX_SERVER_LIMIT
133 #define MAX_SERVER_LIMIT 20000
136 /* Limit on the threads per process. Clients will be locked out if more than
137 * this * server_limit are needed.
139 * We keep this for one reason it keeps the size of the scoreboard file small
140 * enough that we can read the whole thing without worrying too much about
143 #ifndef DEFAULT_THREAD_LIMIT
144 #define DEFAULT_THREAD_LIMIT 64
147 /* Admin can't tune ThreadLimit beyond MAX_THREAD_LIMIT. We want
148 * some sort of compile-time limit to help catch typos.
150 #ifndef MAX_THREAD_LIMIT
151 #define MAX_THREAD_LIMIT 20000
155 * Actual definitions of config globals
158 int ap_threads_per_child = 0; /* Worker threads per child */
159 static int ap_daemons_to_start = 0;
160 static int min_spare_threads = 0;
161 static int max_spare_threads = 0;
162 static int ap_daemons_limit = 0;
163 static int server_limit = DEFAULT_SERVER_LIMIT;
164 static int first_server_limit;
165 static int thread_limit = DEFAULT_THREAD_LIMIT;
166 static int first_thread_limit;
167 static int changed_limit_at_restart;
168 static int dying = 0;
169 static int workers_may_exit = 0;
170 static int requests_this_child;
171 static int num_listensocks = 0;
172 static int resource_shortage = 0;
173 static fd_queue_t *worker_queue;
175 /* The structure used to pass unique initialization info to each thread */
182 /* Structure used to pass information to the thread responsible for
183 * creating the rest of the threads.
186 apr_thread_t **threads;
187 apr_thread_t *listener;
189 apr_threadattr_t *threadattr;
192 #define ID_FROM_CHILD_THREAD(c, t) ((c * thread_limit) + t)
195 * The max child slot ever assigned, preserved across restarts. Necessary
196 * to deal with MaxClients changes across AP_SIG_GRACEFUL restarts. We
197 * use this value to optimize routines that have to scan the entire
200 int ap_max_daemons_limit = -1;
202 static ap_pod_t *pod;
204 /* *Non*-shared http_main globals... */
206 server_rec *ap_server_conf;
208 /* The worker MPM respects a couple of runtime flags that can aid
209 * in debugging. Setting the -DNO_DETACH flag will prevent the root process
210 * from detaching from its controlling terminal. Additionally, setting
211 * the -DONE_PROCESS flag (which implies -DNO_DETACH) will get you the
212 * child_main loop running in the process which originally started up.
213 * This gives you a pretty nice debugging environment. (You'll get a SIGHUP
214 * early in standalone_main; just continue through. This is the server
215 * trying to kill off any child processes which it might have lying
216 * around --- Apache doesn't keep track of their pids, it just sends
217 * SIGHUP to the process group, ignoring it in the root process.
218 * Continue through and you'll be fine.).
221 static int one_process = 0;
224 int raise_sigstop_flags;
227 static apr_pool_t *pconf; /* Pool for config stuff */
228 static apr_pool_t *pchild; /* Pool for httpd child stuff */
230 static pid_t ap_my_pid; /* Linux getpid() doesn't work except in main
231 thread. Use this instead */
232 static pid_t parent_pid;
233 static apr_os_thread_t *listener_os_thread;
235 /* Locks for accept serialization */
236 static apr_proc_mutex_t *accept_mutex;
238 #ifdef SINGLE_LISTEN_UNSERIALIZED_ACCEPT
239 #define SAFE_ACCEPT(stmt) (ap_listeners->next ? (stmt) : APR_SUCCESS)
241 #define SAFE_ACCEPT(stmt) (stmt)
244 /* The LISTENER_SIGNAL signal will be sent from the main thread to the
245 * listener thread to wake it up for graceful termination (what a child
246 * process from an old generation does when the admin does "apachectl
247 * graceful"). This signal will be blocked in all threads of a child
248 * process except for the listener thread.
250 #define LISTENER_SIGNAL SIGHUP
252 static void wakeup_listener(void)
255 * we should just be able to "kill(ap_my_pid, LISTENER_SIGNAL)" and wake
256 * up the listener thread since it is the only thread with SIGHUP
257 * unblocked, but that doesn't work on Linux
259 pthread_kill(*listener_os_thread, LISTENER_SIGNAL);
262 static void signal_workers(void)
264 workers_may_exit = 1;
266 /* in case we weren't called from the listener thread, wake up the
271 /* XXX: This will happen naturally on a graceful, and we don't care
273 ap_queue_signal_all_wakeup(worker_queue); */
274 ap_queue_interrupt_all(worker_queue);
277 AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result)
280 case AP_MPMQ_MAX_DAEMON_USED:
281 *result = ap_max_daemons_limit;
283 case AP_MPMQ_IS_THREADED:
284 *result = AP_MPMQ_STATIC;
286 case AP_MPMQ_IS_FORKED:
287 *result = AP_MPMQ_DYNAMIC;
289 case AP_MPMQ_HARD_LIMIT_DAEMONS:
290 *result = server_limit;
292 case AP_MPMQ_HARD_LIMIT_THREADS:
293 *result = thread_limit;
295 case AP_MPMQ_MAX_THREADS:
296 *result = ap_threads_per_child;
298 case AP_MPMQ_MIN_SPARE_DAEMONS:
301 case AP_MPMQ_MIN_SPARE_THREADS:
302 *result = min_spare_threads;
304 case AP_MPMQ_MAX_SPARE_DAEMONS:
307 case AP_MPMQ_MAX_SPARE_THREADS:
308 *result = max_spare_threads;
310 case AP_MPMQ_MAX_REQUESTS_DAEMON:
311 *result = ap_max_requests_per_child;
313 case AP_MPMQ_MAX_DAEMONS:
314 *result = ap_daemons_limit;
320 /* a clean exit from a child with proper cleanup */
321 static void clean_child_exit(int code) __attribute__ ((noreturn));
322 static void clean_child_exit(int code)
325 apr_pool_destroy(pchild);
330 /* handle all varieties of core dumping signals */
331 static void sig_coredump(int sig)
333 apr_filepath_set(ap_coredump_dir, pconf);
334 apr_signal(sig, SIG_DFL);
335 if (ap_my_pid == parent_pid) {
336 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE,
338 "seg fault or similar nasty error detected "
339 "in the parent process");
341 /* XXX we can probably add some rudimentary cleanup code here,
342 * like getting rid of the pid file. If any additional bad stuff
343 * happens, we are protected from recursive errors taking down the
344 * system since this function is no longer the signal handler GLA
347 kill(ap_my_pid, sig);
348 /* At this point we've got sig blocked, because we're still inside
349 * the signal handler. When we leave the signal handler it will
350 * be unblocked, and we'll take the signal... and coredump or whatever
351 * is appropriate for this particular Unix. In addition the parent
352 * will see the real signal we received -- whereas if we called
353 * abort() here, the parent would only see SIGABRT.
357 static void just_die(int sig)
362 /*****************************************************************
363 * Connection structures and accounting...
366 /* volatile just in case */
367 static int volatile shutdown_pending;
368 static int volatile restart_pending;
369 static int volatile is_graceful;
370 static volatile int child_fatal;
371 ap_generation_t volatile ap_my_generation;
374 * ap_start_shutdown() and ap_start_restart(), below, are a first stab at
375 * functions to initiate shutdown or restart without relying on signals.
376 * Previously this was initiated in sig_term() and restart() signal handlers,
377 * but we want to be able to start a shutdown/restart from other sources --
378 * e.g. on Win32, from the service manager. Now the service manager can
379 * call ap_start_shutdown() or ap_start_restart() as appropiate. Note that
380 * these functions can also be called by the child processes, since global
381 * variables are no longer used to pass on the required action to the parent.
383 * These should only be called from the parent process itself, since the
384 * parent process will use the shutdown_pending and restart_pending variables
385 * to determine whether to shutdown or restart. The child process should
386 * call signal_parent() directly to tell the parent to die -- this will
387 * cause neither of those variable to be set, which the parent will
388 * assume means something serious is wrong (which it will be, for the
389 * child to force an exit) and so do an exit anyway.
392 static void ap_start_shutdown(void)
394 if (shutdown_pending == 1) {
395 /* Um, is this _probably_ not an error, if the user has
396 * tried to do a shutdown twice quickly, so we won't
397 * worry about reporting it.
401 shutdown_pending = 1;
404 /* do a graceful restart if graceful == 1 */
405 static void ap_start_restart(int graceful)
408 if (restart_pending == 1) {
409 /* Probably not an error - don't bother reporting it */
413 is_graceful = graceful;
415 apr_pool_cleanup_kill(pconf, NULL, ap_cleanup_scoreboard);
419 static void sig_term(int sig)
424 static void restart(int sig)
426 ap_start_restart(sig == AP_SIG_GRACEFUL);
429 static void set_signals(void)
431 #ifndef NO_USE_SIGACTION
434 sigemptyset(&sa.sa_mask);
438 sa.sa_handler = sig_coredump;
439 #if defined(SA_ONESHOT)
440 sa.sa_flags = SA_ONESHOT;
441 #elif defined(SA_RESETHAND)
442 sa.sa_flags = SA_RESETHAND;
444 if (sigaction(SIGSEGV, &sa, NULL) < 0)
445 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
446 "sigaction(SIGSEGV)");
448 if (sigaction(SIGBUS, &sa, NULL) < 0)
449 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
450 "sigaction(SIGBUS)");
453 if (sigaction(SIGABORT, &sa, NULL) < 0)
454 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
455 "sigaction(SIGABORT)");
458 if (sigaction(SIGABRT, &sa, NULL) < 0)
459 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
460 "sigaction(SIGABRT)");
463 if (sigaction(SIGILL, &sa, NULL) < 0)
464 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
465 "sigaction(SIGILL)");
469 sa.sa_handler = sig_term;
470 if (sigaction(SIGTERM, &sa, NULL) < 0)
471 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
472 "sigaction(SIGTERM)");
474 if (sigaction(SIGINT, &sa, NULL) < 0)
475 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
476 "sigaction(SIGINT)");
479 sa.sa_handler = SIG_DFL;
480 if (sigaction(SIGXCPU, &sa, NULL) < 0)
481 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
482 "sigaction(SIGXCPU)");
485 sa.sa_handler = SIG_DFL;
486 if (sigaction(SIGXFSZ, &sa, NULL) < 0)
487 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
488 "sigaction(SIGXFSZ)");
491 sa.sa_handler = SIG_IGN;
492 if (sigaction(SIGPIPE, &sa, NULL) < 0)
493 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
494 "sigaction(SIGPIPE)");
497 /* we want to ignore HUPs and AP_SIG_GRACEFUL while we're busy
499 sigaddset(&sa.sa_mask, SIGHUP);
500 sigaddset(&sa.sa_mask, AP_SIG_GRACEFUL);
501 sa.sa_handler = restart;
502 if (sigaction(SIGHUP, &sa, NULL) < 0)
503 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
504 "sigaction(SIGHUP)");
505 if (sigaction(AP_SIG_GRACEFUL, &sa, NULL) < 0)
506 ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
507 "sigaction(" AP_SIG_GRACEFUL_STRING ")");
510 apr_signal(SIGSEGV, sig_coredump);
512 apr_signal(SIGBUS, sig_coredump);
515 apr_signal(SIGABORT, sig_coredump);
516 #endif /* SIGABORT */
518 apr_signal(SIGABRT, sig_coredump);
521 apr_signal(SIGILL, sig_coredump);
524 apr_signal(SIGXCPU, SIG_DFL);
527 apr_signal(SIGXFSZ, SIG_DFL);
531 apr_signal(SIGTERM, sig_term);
533 apr_signal(SIGHUP, restart);
535 #ifdef AP_SIG_GRACEFUL
536 apr_signal(AP_SIG_GRACEFUL, restart);
537 #endif /* AP_SIG_GRACEFUL */
539 apr_signal(SIGPIPE, SIG_IGN);
545 /*****************************************************************
546 * Here follows a long bunch of generic server bookkeeping stuff...
549 int ap_graceful_stop_signalled(void)
550 /* XXX this is really a bad confusing obsolete name
551 * maybe it should be ap_mpm_process_exiting?
554 return workers_may_exit;
557 /*****************************************************************
558 * Child process main loop.
561 static void process_socket(apr_pool_t *p, apr_socket_t *sock, int my_child_num,
564 conn_rec *current_conn;
565 long conn_id = ID_FROM_CHILD_THREAD(my_child_num, my_thread_num);
569 ap_create_sb_handle(&sbh, p, my_child_num, my_thread_num);
570 apr_os_sock_get(&csd, sock);
572 if (csd >= FD_SETSIZE) {
573 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, NULL,
574 "new file descriptor %d is too large; you probably need "
575 "to rebuild Apache with a larger FD_SETSIZE "
578 apr_socket_close(sock);
582 current_conn = ap_run_create_connection(p, ap_server_conf, sock, conn_id, sbh);
584 ap_process_connection(current_conn, sock);
585 ap_lingering_close(current_conn);
589 /* requests_this_child has gone to zero or below. See if the admin coded
590 "MaxRequestsPerChild 0", and keep going in that case. Doing it this way
591 simplifies the hot path in worker_thread */
592 static void check_infinite_requests(void)
594 if (ap_max_requests_per_child) {
598 /* wow! if you're executing this code, you may have set a record.
599 * either this child process has served over 2 billion requests, or
600 * you're running a threaded 2.0 on a 16 bit machine.
602 * I'll buy pizza and beers at Apachecon for the first person to do
603 * the former without cheating (dorking with INT_MAX, or running with
604 * uncommitted performance patches, for example).
606 * for the latter case, you probably deserve a beer too. Greg Ames
609 requests_this_child = INT_MAX; /* keep going */
613 static void unblock_the_listener(int sig)
615 /* XXX If specifying SIG_IGN is guaranteed to unblock a syscall,
616 * then we don't need this goofy function.
620 static void *listener_thread(apr_thread_t *thd, void * dummy)
622 proc_info * ti = dummy;
623 int process_slot = ti->pid;
624 int thread_slot = ti->tid;
625 apr_pool_t *tpool = apr_thread_pool_get(thd);
627 apr_pool_t *ptrans; /* Pool for per-transaction stuff */
628 apr_pool_t *recycled_pool = NULL;
630 apr_pollfd_t *pollset;
632 ap_listen_rec *lr, *last_lr = ap_listeners;
638 apr_poll_setup(&pollset, num_listensocks, tpool);
639 for(lr = ap_listeners ; lr != NULL ; lr = lr->next)
640 apr_poll_socket_add(pollset, lr->sd, APR_POLLIN);
642 sigemptyset(&sig_mask);
643 /* Unblock the signal used to wake this thread up, and set a handler for
646 sigaddset(&sig_mask, LISTENER_SIGNAL);
647 #if defined(SIGPROCMASK_SETS_THREAD_MASK)
648 sigprocmask(SIG_UNBLOCK, &sig_mask, NULL);
650 pthread_sigmask(SIG_UNBLOCK, &sig_mask, NULL);
652 sigemptyset(&sa.sa_mask);
654 sa.sa_handler = unblock_the_listener;
655 sigaction(LISTENER_SIGNAL, &sa, NULL);
657 /* TODO: Switch to a system where threads reuse the results from earlier
658 poll calls - manoj */
660 /* TODO: requests_this_child should be synchronized - aaron */
661 if (requests_this_child <= 0) {
662 check_infinite_requests();
664 if (workers_may_exit) break;
666 if ((rv = SAFE_ACCEPT(apr_proc_mutex_lock(accept_mutex)))
668 int level = APLOG_EMERG;
670 if (workers_may_exit) {
673 if (ap_scoreboard_image->parent[process_slot].generation !=
674 ap_scoreboard_image->global->running_generation) {
675 level = APLOG_DEBUG; /* common to get these at restart time */
677 ap_log_error(APLOG_MARK, level, rv, ap_server_conf,
678 "apr_proc_mutex_lock failed. Attempting to shutdown "
679 "process gracefully.");
681 break; /* skip the lock release */
684 if (!ap_listeners->next) {
685 /* Only one listener, so skip the poll */
689 while (!workers_may_exit) {
693 ret = apr_poll(pollset, &n, -1);
694 if (ret != APR_SUCCESS) {
695 if (APR_STATUS_IS_EINTR(ret)) {
699 /* apr_poll() will only return errors in catastrophic
700 * circumstances. Let's try exiting gracefully, for now. */
701 ap_log_error(APLOG_MARK, APLOG_ERR, ret, (const server_rec *)
702 ap_server_conf, "apr_poll: (listen)");
706 if (workers_may_exit) break;
708 /* find a listener */
715 /* XXX: Should we check for POLLERR? */
716 apr_poll_revents_get(&event, lr->sd, pollset);
717 if (event & APR_POLLIN) {
721 } while (lr != last_lr);
725 if (!workers_may_exit) {
726 /* create a new transaction pool for each accepted socket */
727 if (recycled_pool == NULL) {
728 apr_allocator_t *allocator;
730 apr_allocator_create(&allocator);
731 apr_pool_create_ex(&ptrans, NULL, NULL, allocator);
732 apr_allocator_set_owner(allocator, ptrans);
735 ptrans = recycled_pool;
737 apr_pool_tag(ptrans, "transaction");
738 rv = lr->accept_func(&csd, lr, ptrans);
740 /* If we were interrupted for whatever reason, just start
741 * the main loop over again.
743 if (APR_STATUS_IS_EINTR(rv)) {
746 if (rv == APR_EGENERAL) {
747 /* E[NM]FILE, ENOMEM, etc */
748 resource_shortage = 1;
751 if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(accept_mutex)))
753 int level = APLOG_EMERG;
755 if (workers_may_exit) {
758 if (ap_scoreboard_image->parent[process_slot].generation !=
759 ap_scoreboard_image->global->running_generation) {
760 level = APLOG_DEBUG; /* common to get these at restart time */
762 ap_log_error(APLOG_MARK, level, rv, ap_server_conf,
763 "apr_proc_mutex_unlock failed. Attempting to "
764 "shutdown process gracefully.");
768 rv = ap_queue_push(worker_queue, csd, ptrans,
771 /* trash the connection; we couldn't queue the connected
774 apr_socket_close(csd);
775 ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
776 "ap_queue_push failed");
781 if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(accept_mutex)))
783 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
784 "apr_proc_mutex_unlock failed. Attempting to "
785 "shutdown process gracefully.");
792 ap_update_child_status_from_indexes(process_slot, thread_slot,
793 (dying) ? SERVER_DEAD : SERVER_GRACEFUL,
794 (request_rec *) NULL);
796 ap_scoreboard_image->parent[process_slot].quiescing = 1;
797 kill(ap_my_pid, SIGTERM);
799 apr_thread_exit(thd, APR_SUCCESS);
803 static void * APR_THREAD_FUNC worker_thread(apr_thread_t *thd, void * dummy)
805 proc_info * ti = dummy;
806 int process_slot = ti->pid;
807 int thread_slot = ti->tid;
808 apr_socket_t *csd = NULL;
809 apr_pool_t *last_ptrans = NULL;
810 apr_pool_t *ptrans; /* Pool for per-transaction stuff */
815 ap_update_child_status_from_indexes(process_slot, thread_slot, SERVER_STARTING, NULL);
816 while (!workers_may_exit) {
817 ap_update_child_status_from_indexes(process_slot, thread_slot, SERVER_READY, NULL);
818 rv = ap_queue_pop(worker_queue, &csd, &ptrans, last_ptrans);
821 /* We get APR_EINTR whenever ap_queue_pop() has been interrupted
822 * from an explicit call to ap_queue_interrupt_all(). This allows
823 * us to unblock threads stuck in ap_queue_pop() when a shutdown
825 if (rv == APR_EINTR || !csd) {
828 process_socket(ptrans, csd, process_slot, thread_slot);
829 requests_this_child--; /* FIXME: should be synchronized - aaron */
830 apr_pool_clear(ptrans);
831 last_ptrans = ptrans;
834 ap_update_child_status_from_indexes(process_slot, thread_slot,
835 (dying) ? SERVER_DEAD : SERVER_GRACEFUL, (request_rec *) NULL);
837 apr_thread_exit(thd, APR_SUCCESS);
841 static int check_signal(int signum)
851 /* XXX unfortunate issue:
852 * with apachectl restart (not graceful), previous generation dies
853 * abruptly with no chance to clean up scoreboard entries; when new
854 * generation is started, processes can loop forever in start_threads()
855 * waiting for scoreboard entries for threads of prior generation to
856 * get cleaned up... but it will never happen and the new generation
857 * child looping here, waiting for scoreboard to get cleaned up, is
860 static void * APR_THREAD_FUNC start_threads(apr_thread_t *thd, void *dummy)
862 thread_starter *ts = dummy;
863 apr_thread_t **threads = ts->threads;
864 apr_threadattr_t *thread_attr = ts->threadattr;
865 int child_num_arg = ts->child_num_arg;
866 int my_child_num = child_num_arg;
867 proc_info *my_info = NULL;
870 int threads_created = 0;
872 /* We must create the fd queues before we start up the listener
873 * and worker threads. */
874 worker_queue = apr_pcalloc(pchild, sizeof(*worker_queue));
875 rv = ap_queue_init(worker_queue, ap_threads_per_child, pchild);
876 if (rv != APR_SUCCESS) {
877 ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
878 "ap_queue_init() failed");
879 clean_child_exit(APEXIT_CHILDFATAL);
882 my_info = (proc_info *)malloc(sizeof(proc_info));
883 my_info->pid = my_child_num;
886 rv = apr_thread_create(&ts->listener, thread_attr, listener_thread,
888 if (rv != APR_SUCCESS) {
889 ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
890 "apr_thread_create: unable to create listener thread");
891 /* In case system resources are maxxed out, we don't want
892 * Apache running away with the CPU trying to fork over and
893 * over and over again if we exit.
894 * XXX Jeff doesn't see how Apache is going to try to fork again since
895 * the exit code is APEXIT_CHILDFATAL
897 apr_sleep(10 * APR_USEC_PER_SEC);
898 clean_child_exit(APEXIT_CHILDFATAL);
900 apr_os_thread_get(&listener_os_thread, ts->listener);
902 /* ap_threads_per_child does not include the listener thread */
903 for (i = 0; i < ap_threads_per_child; i++) {
904 int status = ap_scoreboard_image->servers[child_num_arg][i].status;
906 if (status != SERVER_GRACEFUL && status != SERVER_DEAD) {
910 my_info = (proc_info *)malloc(sizeof(proc_info));
911 if (my_info == NULL) {
912 ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf,
913 "malloc: out of memory");
914 clean_child_exit(APEXIT_CHILDFATAL);
916 my_info->pid = my_child_num;
920 /* We are creating threads right now */
921 ap_update_child_status_from_indexes(my_child_num, i,
922 SERVER_STARTING, NULL);
923 /* We let each thread update its own scoreboard entry. This is
924 * done because it lets us deal with tid better.
926 rv = apr_thread_create(&threads[i], thread_attr,
927 worker_thread, my_info, pchild);
928 if (rv != APR_SUCCESS) {
929 ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
930 "apr_thread_create: unable to create worker thread");
931 /* In case system resources are maxxed out, we don't want
932 Apache running away with the CPU trying to fork over and
933 over and over again if we exit. */
934 apr_sleep(10 * APR_USEC_PER_SEC);
935 clean_child_exit(APEXIT_CHILDFATAL);
939 if (workers_may_exit || threads_created == ap_threads_per_child) {
942 /* wait for previous generation to clean up an entry */
943 apr_sleep(1 * APR_USEC_PER_SEC);
946 /* What state should this child_main process be listed as in the
948 * ap_update_child_status_from_indexes(my_child_num, i, SERVER_STARTING,
949 * (request_rec *) NULL);
951 * This state should be listed separately in the scoreboard, in some kind
952 * of process_status, not mixed in with the worker threads' status.
953 * "life_status" is almost right, but it's in the worker's structure, and
954 * the name could be clearer. gla
956 apr_thread_exit(thd, APR_SUCCESS);
960 static void join_workers(apr_thread_t *listener, apr_thread_t **threads)
963 apr_status_t rv, thread_rv;
968 /* deal with a rare timing window which affects waking up the
969 * listener thread... if the signal sent to the listener thread
970 * is delivered between the time it verifies that the
971 * workers_may_exit flag is clear and the time it enters a
972 * blocking syscall, the signal didn't do any good... work around
973 * that by sleeping briefly and sending it again
977 while (iter < 10 && pthread_kill(*listener_os_thread, 0) == 0) {
978 /* listener not dead yet */
979 apr_sleep(APR_USEC_PER_SEC / 2);
984 ap_log_error(APLOG_MARK, APLOG_CRIT, 0, ap_server_conf,
985 "the listener thread didn't exit");
988 rv = apr_thread_join(&thread_rv, listener);
989 if (rv != APR_SUCCESS) {
990 ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
991 "apr_thread_join: unable to join listener thread");
996 for (i = 0; i < ap_threads_per_child; i++) {
997 if (threads[i]) { /* if we ever created this thread */
998 rv = apr_thread_join(&thread_rv, threads[i]);
999 if (rv != APR_SUCCESS) {
1000 ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
1001 "apr_thread_join: unable to join worker "
1009 static void join_start_thread(apr_thread_t *start_thread_id)
1011 apr_status_t rv, thread_rv;
1013 workers_may_exit = 1; /* start thread may not want to exit until this
1016 rv = apr_thread_join(&thread_rv, start_thread_id);
1017 if (rv != APR_SUCCESS) {
1018 ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
1019 "apr_thread_join: unable to join the start "
1024 static void child_main(int child_num_arg)
1026 apr_thread_t **threads;
1029 apr_threadattr_t *thread_attr;
1030 apr_thread_t *start_thread_id;
1032 ap_my_pid = getpid();
1033 apr_pool_create(&pchild, pconf);
1035 /*stuff to do before we switch id's, so we have permissions.*/
1036 ap_reopen_scoreboard(pchild, NULL, 0);
1038 rv = SAFE_ACCEPT(apr_proc_mutex_child_init(&accept_mutex, ap_lock_fname,
1040 if (rv != APR_SUCCESS) {
1041 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
1042 "Couldn't initialize cross-process lock in child");
1043 clean_child_exit(APEXIT_CHILDFATAL);
1046 if (unixd_setup_child()) {
1047 clean_child_exit(APEXIT_CHILDFATAL);
1050 ap_run_child_init(pchild, ap_server_conf);
1052 /* done with init critical section */
1054 /* Just use the standard apr_setup_signal_thread to block all signals
1055 * from being received. The child processes no longer use signals for
1056 * any communication with the parent process.
1058 rv = apr_setup_signal_thread();
1059 if (rv != APR_SUCCESS) {
1060 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
1061 "Couldn't initialize signal thread");
1062 clean_child_exit(APEXIT_CHILDFATAL);
1065 if (ap_max_requests_per_child) {
1066 requests_this_child = ap_max_requests_per_child;
1069 /* coding a value of zero means infinity */
1070 requests_this_child = INT_MAX;
1073 /* Setup worker threads */
1075 /* clear the storage; we may not create all our threads immediately,
1076 * and we want a 0 entry to indicate a thread which was not created
1078 threads = (apr_thread_t **)calloc(1,
1079 sizeof(apr_thread_t *) * ap_threads_per_child);
1080 if (threads == NULL) {
1081 ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf,
1082 "malloc: out of memory");
1083 clean_child_exit(APEXIT_CHILDFATAL);
1086 ts = (thread_starter *)apr_palloc(pchild, sizeof(*ts));
1088 apr_threadattr_create(&thread_attr, pchild);
1089 /* 0 means PTHREAD_CREATE_JOINABLE */
1090 apr_threadattr_detach_set(thread_attr, 0);
1092 ts->threads = threads;
1093 ts->listener = NULL;
1094 ts->child_num_arg = child_num_arg;
1095 ts->threadattr = thread_attr;
1097 rv = apr_thread_create(&start_thread_id, thread_attr, start_threads,
1099 if (rv != APR_SUCCESS) {
1100 ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
1101 "apr_thread_create: unable to create worker thread");
1102 /* In case system resources are maxxed out, we don't want
1103 Apache running away with the CPU trying to fork over and
1104 over and over again if we exit. */
1105 apr_sleep(10 * APR_USEC_PER_SEC);
1106 clean_child_exit(APEXIT_CHILDFATAL);
1109 /* If we are only running in one_process mode, we will want to
1110 * still handle signals. */
1112 /* Set up a signal handler for this thread. */
1113 apr_signal_thread(check_signal);
1114 /* make sure the start thread has finished; signal_workers()
1115 * and join_workers() depend on that
1117 join_start_thread(start_thread_id);
1118 signal_workers(); /* helps us terminate a little more quickly when
1119 * the dispatch of the signal thread
1120 * beats the Pipe of Death and the browsers
1122 /* A terminating signal was received. Now join each of the
1123 * workers to clean them up.
1124 * If the worker already exited, then the join frees
1125 * their resources and returns.
1126 * If the worker hasn't exited, then this blocks until
1127 * they have (then cleans up).
1129 join_workers(ts->listener, threads);
1131 else { /* !one_process */
1132 /* Watch for any messages from the parent over the POD */
1134 rv = ap_mpm_pod_check(pod);
1135 if (rv == AP_GRACEFUL || rv == AP_RESTART) {
1136 /* make sure the start thread has finished;
1137 * signal_workers() and join_workers depend on that
1139 join_start_thread(start_thread_id);
1145 if (rv == AP_GRACEFUL) {
1146 /* A terminating signal was received. Now join each of the
1147 * workers to clean them up.
1148 * If the worker already exited, then the join frees
1149 * their resources and returns.
1150 * If the worker hasn't exited, then this blocks until
1151 * they have (then cleans up).
1153 join_workers(ts->listener, threads);
1159 clean_child_exit(resource_shortage ? APEXIT_CHILDSICK : 0);
1162 static int make_child(server_rec *s, int slot)
1166 if (slot + 1 > ap_max_daemons_limit) {
1167 ap_max_daemons_limit = slot + 1;
1172 ap_scoreboard_image->parent[slot].pid = getpid();
1176 if ((pid = fork()) == -1) {
1177 ap_log_error(APLOG_MARK, APLOG_ERR, errno, s,
1178 "fork: Unable to fork new process");
1180 /* fork didn't succeed. Fix the scoreboard or else
1181 * it will say SERVER_STARTING forever and ever
1183 ap_update_child_status_from_indexes(slot, 0, SERVER_DEAD, NULL);
1185 /* In case system resources are maxxed out, we don't want
1186 Apache running away with the CPU trying to fork over and
1187 over and over again. */
1188 apr_sleep(10 * APR_USEC_PER_SEC);
1194 #ifdef HAVE_BINDPROCESSOR
1195 /* By default, AIX binds to a single processor. This bit unbinds
1196 * children which will then bind to another CPU.
1198 int status = bindprocessor(BINDPROCESS, (int)getpid(),
1199 PROCESSOR_CLASS_ANY);
1201 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, errno,
1203 "processor unbind failed %d", status);
1205 RAISE_SIGSTOP(MAKE_CHILD);
1207 apr_signal(SIGTERM, just_die);
1210 clean_child_exit(0);
1213 ap_scoreboard_image->parent[slot].quiescing = 0;
1214 ap_scoreboard_image->parent[slot].pid = pid;
1218 /* start up a bunch of children */
1219 static void startup_children(int number_to_start)
1223 for (i = 0; number_to_start && i < ap_daemons_limit; ++i) {
1224 if (ap_scoreboard_image->parent[i].pid != 0) {
1227 if (make_child(ap_server_conf, i) < 0) {
1236 * idle_spawn_rate is the number of children that will be spawned on the
1237 * next maintenance cycle if there aren't enough idle servers. It is
1238 * doubled up to MAX_SPAWN_RATE, and reset only when a cycle goes by
1239 * without the need to spawn.
1241 static int idle_spawn_rate = 1;
1242 #ifndef MAX_SPAWN_RATE
1243 #define MAX_SPAWN_RATE (32)
1245 static int hold_off_on_exponential_spawning;
1247 static void perform_idle_server_maintenance(void)
1250 int idle_thread_count;
1254 int totally_free_length = 0;
1255 int free_slots[MAX_SPAWN_RATE];
1259 /* initialize the free_list */
1262 idle_thread_count = 0;
1266 ap_sync_scoreboard_image();
1267 for (i = 0; i < ap_daemons_limit; ++i) {
1268 /* Initialization to satisfy the compiler. It doesn't know
1269 * that ap_threads_per_child is always > 0 */
1270 int status = SERVER_DEAD;
1271 int any_dying_threads = 0;
1272 int any_dead_threads = 0;
1273 int all_dead_threads = 1;
1275 if (i >= ap_max_daemons_limit && totally_free_length == idle_spawn_rate)
1277 ps = &ap_scoreboard_image->parent[i];
1278 for (j = 0; j < ap_threads_per_child; j++) {
1279 ws = &ap_scoreboard_image->servers[i][j];
1280 status = ws->status;
1282 /* XXX any_dying_threads is probably no longer needed GLA */
1283 any_dying_threads = any_dying_threads ||
1284 (status == SERVER_GRACEFUL);
1285 any_dead_threads = any_dead_threads || (status == SERVER_DEAD);
1286 all_dead_threads = all_dead_threads &&
1287 (status == SERVER_DEAD ||
1288 status == SERVER_GRACEFUL);
1290 /* We consider a starting server as idle because we started it
1291 * at least a cycle ago, and if it still hasn't finished starting
1292 * then we're just going to swamp things worse by forking more.
1293 * So we hopefully won't need to fork more if we count it.
1294 * This depends on the ordering of SERVER_READY and SERVER_STARTING.
1296 if (status <= SERVER_READY && status != SERVER_DEAD &&
1298 ps->generation == ap_my_generation &&
1299 /* XXX the following shouldn't be necessary if we clean up
1300 * properly after seg faults, but we're not yet GLA
1303 ++idle_thread_count;
1306 if (any_dead_threads && totally_free_length < idle_spawn_rate
1307 && (!ps->pid /* no process in the slot */
1308 || ps->quiescing)) { /* or at least one is going away */
1309 if (all_dead_threads) {
1310 /* great! we prefer these, because the new process can
1311 * start more threads sooner. So prioritize this slot
1312 * by putting it ahead of any slots with active threads.
1314 * first, make room by moving a slot that's potentially still
1315 * in use to the end of the array
1317 free_slots[free_length] = free_slots[totally_free_length];
1318 free_slots[totally_free_length++] = i;
1321 /* slot is still in use - back of the bus
1323 free_slots[free_length] = i;
1327 /* XXX if (!ps->quiescing) is probably more reliable GLA */
1328 if (!any_dying_threads) {
1333 ap_max_daemons_limit = last_non_dead + 1;
1335 if (idle_thread_count > max_spare_threads) {
1336 /* Kill off one child */
1337 ap_mpm_pod_signal(pod, TRUE);
1338 idle_spawn_rate = 1;
1340 else if (idle_thread_count < min_spare_threads) {
1341 /* terminate the free list */
1342 if (free_length == 0) {
1343 /* only report this condition once */
1344 static int reported = 0;
1347 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, 0,
1349 "server reached MaxClients setting, consider"
1350 " raising the MaxClients setting");
1353 idle_spawn_rate = 1;
1356 if (free_length > idle_spawn_rate) {
1357 free_length = idle_spawn_rate;
1359 if (idle_spawn_rate >= 8) {
1360 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, 0,
1362 "server seems busy, (you may need "
1363 "to increase StartServers, ThreadsPerChild "
1364 "or Min/MaxSpareThreads), "
1365 "spawning %d children, there are around %d idle "
1366 "threads, and %d total children", free_length,
1367 idle_thread_count, total_non_dead);
1369 for (i = 0; i < free_length; ++i) {
1370 make_child(ap_server_conf, free_slots[i]);
1372 /* the next time around we want to spawn twice as many if this
1373 * wasn't good enough, but not if we've just done a graceful
1375 if (hold_off_on_exponential_spawning) {
1376 --hold_off_on_exponential_spawning;
1378 else if (idle_spawn_rate < MAX_SPAWN_RATE) {
1379 idle_spawn_rate *= 2;
1384 idle_spawn_rate = 1;
1388 static void server_main_loop(int remaining_children_to_start)
1391 apr_exit_why_e exitwhy;
1392 int status, processed_status;
1396 while (!restart_pending && !shutdown_pending) {
1397 ap_wait_or_timeout(&exitwhy, &status, &pid, pconf);
1399 if (pid.pid != -1) {
1400 processed_status = ap_process_child_status(&pid, exitwhy, status);
1401 if (processed_status == APEXIT_CHILDFATAL) {
1402 shutdown_pending = 1;
1406 /* non-fatal death... note that it's gone in the scoreboard. */
1407 child_slot = find_child_by_pid(&pid);
1408 if (child_slot >= 0) {
1409 for (i = 0; i < ap_threads_per_child; i++)
1410 ap_update_child_status_from_indexes(child_slot, i, SERVER_DEAD,
1411 (request_rec *) NULL);
1413 ap_scoreboard_image->parent[child_slot].pid = 0;
1414 ap_scoreboard_image->parent[child_slot].quiescing = 0;
1415 if (processed_status == APEXIT_CHILDSICK) {
1416 /* resource shortage, minimize the fork rate */
1417 idle_spawn_rate = 1;
1419 else if (remaining_children_to_start
1420 && child_slot < ap_daemons_limit) {
1421 /* we're still doing a 1-for-1 replacement of dead
1422 * children with new children
1424 make_child(ap_server_conf, child_slot);
1425 --remaining_children_to_start;
1427 #if APR_HAS_OTHER_CHILD
1429 else if (apr_proc_other_child_read(&pid, status) == 0) {
1433 else if (is_graceful) {
1434 /* Great, we've probably just lost a slot in the
1435 * scoreboard. Somehow we don't know about this child.
1437 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0,
1439 "long lost child came home! (pid %ld)",
1442 /* Don't perform idle maintenance when a child dies,
1443 * only do it when there's a timeout. Remember only a
1444 * finite number of children can die, and it's pretty
1445 * pathological for a lot to die suddenly.
1449 else if (remaining_children_to_start) {
1450 /* we hit a 1 second timeout in which none of the previous
1451 * generation of children needed to be reaped... so assume
1452 * they're all done, and pick up the slack if any is left.
1454 startup_children(remaining_children_to_start);
1455 remaining_children_to_start = 0;
1456 /* In any event we really shouldn't do the code below because
1457 * few of the servers we just started are in the IDLE state
1458 * yet, so we'd mistakenly create an extra server.
1463 perform_idle_server_maintenance();
1467 int ap_mpm_run(apr_pool_t *_pconf, apr_pool_t *plog, server_rec *s)
1469 int remaining_children_to_start;
1472 ap_log_pid(pconf, ap_pid_fname);
1474 first_server_limit = server_limit;
1475 first_thread_limit = thread_limit;
1476 if (changed_limit_at_restart) {
1477 ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_NOERRNO, 0, s,
1478 "WARNING: Attempt to change ServerLimit or ThreadLimit "
1479 "ignored during restart");
1480 changed_limit_at_restart = 0;
1483 /* Initialize cross-process accept lock */
1484 ap_lock_fname = apr_psprintf(_pconf, "%s.%" APR_PID_T_FMT,
1485 ap_server_root_relative(_pconf, ap_lock_fname),
1488 rv = apr_proc_mutex_create(&accept_mutex, ap_lock_fname,
1489 ap_accept_lock_mech, _pconf);
1490 if (rv != APR_SUCCESS) {
1491 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
1492 "Couldn't create accept lock");
1496 #if APR_USE_SYSVSEM_SERIALIZE
1497 if (ap_accept_lock_mech == APR_LOCK_DEFAULT ||
1498 ap_accept_lock_mech == APR_LOCK_SYSVSEM) {
1500 if (ap_accept_lock_mech == APR_LOCK_SYSVSEM) {
1502 rv = unixd_set_proc_mutex_perms(accept_mutex);
1503 if (rv != APR_SUCCESS) {
1504 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
1505 "Couldn't set permissions on cross-process lock");
1511 if (ap_run_pre_mpm(pconf, SB_SHARED) != OK) {
1514 /* fix the generation number in the global score; we just got a new,
1515 * cleared scoreboard
1517 ap_scoreboard_image->global->running_generation = ap_my_generation;
1518 update_scoreboard_global();
1522 /* Don't thrash... */
1523 if (max_spare_threads < min_spare_threads + ap_threads_per_child)
1524 max_spare_threads = min_spare_threads + ap_threads_per_child;
1526 /* If we're doing a graceful_restart then we're going to see a lot
1527 * of children exiting immediately when we get into the main loop
1528 * below (because we just sent them AP_SIG_GRACEFUL). This happens pretty
1529 * rapidly... and for each one that exits we'll start a new one until
1530 * we reach at least daemons_min_free. But we may be permitted to
1531 * start more than that, so we'll just keep track of how many we're
1532 * supposed to start up without the 1 second penalty between each fork.
1534 remaining_children_to_start = ap_daemons_to_start;
1535 if (remaining_children_to_start > ap_daemons_limit) {
1536 remaining_children_to_start = ap_daemons_limit;
1539 startup_children(remaining_children_to_start);
1540 remaining_children_to_start = 0;
1543 /* give the system some time to recover before kicking into
1544 * exponential mode */
1545 hold_off_on_exponential_spawning = 10;
1548 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
1549 "%s configured -- resuming normal operations",
1550 ap_get_server_version());
1551 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, 0, ap_server_conf,
1552 "Server built: %s", ap_get_server_built());
1553 restart_pending = shutdown_pending = 0;
1555 server_main_loop(remaining_children_to_start);
1557 if (shutdown_pending) {
1558 /* Time to gracefully shut down:
1559 * Kill child processes, tell them to call child_exit, etc...
1560 * (By "gracefully" we don't mean graceful in the same sense as
1561 * "apachectl graceful" where we allow old connections to finish.)
1563 ap_mpm_pod_killpg(pod, ap_daemons_limit, FALSE);
1564 ap_reclaim_child_processes(1); /* Start with SIGTERM */
1567 /* cleanup pid file on normal shutdown */
1568 const char *pidfile = NULL;
1569 pidfile = ap_server_root_relative (pconf, ap_pid_fname);
1570 if ( pidfile != NULL && unlink(pidfile) == 0)
1571 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, 0,
1573 "removed PID file %s (pid=%ld)",
1574 pidfile, (long)getpid());
1576 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0,
1577 ap_server_conf, "caught SIGTERM, shutting down");
1582 /* we've been told to restart */
1583 apr_signal(SIGHUP, SIG_IGN);
1586 /* not worth thinking about */
1590 /* advance to the next generation */
1591 /* XXX: we really need to make sure this new generation number isn't in
1592 * use by any of the children.
1595 ap_scoreboard_image->global->running_generation = ap_my_generation;
1596 update_scoreboard_global();
1599 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
1600 AP_SIG_GRACEFUL_STRING " received. Doing graceful restart");
1601 /* wake up the children...time to die. But we'll have more soon */
1602 ap_mpm_pod_killpg(pod, ap_daemons_limit, TRUE);
1605 /* This is mostly for debugging... so that we know what is still
1606 * gracefully dealing with existing request.
1611 /* Kill 'em all. Since the child acts the same on the parents SIGTERM
1612 * and a SIGHUP, we may as well use the same signal, because some user
1613 * pthreads are stealing signals from us left and right.
1615 ap_mpm_pod_killpg(pod, ap_daemons_limit, FALSE);
1617 ap_reclaim_child_processes(1); /* Start with SIGTERM */
1618 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
1619 "SIGHUP received. Attempting to restart");
1625 /* This really should be a post_config hook, but the error log is already
1626 * redirected by that point, so we need to do this in the open_logs phase.
1628 static int worker_open_logs(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s)
1635 if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) {
1636 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ALERT|APLOG_STARTUP, 0,
1637 NULL, "no listening sockets available, shutting down");
1642 if ((rv = ap_mpm_pod_open(pconf, &pod))) {
1643 ap_log_error(APLOG_MARK, APLOG_CRIT|APLOG_STARTUP, rv, NULL,
1644 "Could not open pipe-of-death.");
1651 static int worker_pre_config(apr_pool_t *pconf, apr_pool_t *plog,
1654 static int restart_num = 0;
1655 int no_detach, debug;
1656 ap_directive_t *pdir;
1657 ap_directive_t *max_clients = NULL;
1660 /* make sure that "ThreadsPerChild" gets set before "MaxClients" */
1661 for (pdir = ap_conftree; pdir != NULL; pdir = pdir->next) {
1662 if (strncasecmp(pdir->directive, "ThreadsPerChild", 15) == 0) {
1664 break; /* we're in the clear, got ThreadsPerChild first */
1667 /* now to swap the data */
1668 ap_directive_t temp;
1670 temp.directive = pdir->directive;
1671 temp.args = pdir->args;
1672 /* Make sure you don't change 'next', or you may get loops! */
1673 /* XXX: first_child, parent, and data can never be set
1674 * for these directives, right? -aaron */
1675 temp.filename = pdir->filename;
1676 temp.line_num = pdir->line_num;
1678 pdir->directive = max_clients->directive;
1679 pdir->args = max_clients->args;
1680 pdir->filename = max_clients->filename;
1681 pdir->line_num = max_clients->line_num;
1683 max_clients->directive = temp.directive;
1684 max_clients->args = temp.args;
1685 max_clients->filename = temp.filename;
1686 max_clients->line_num = temp.line_num;
1690 else if (!max_clients
1691 && strncasecmp(pdir->directive, "MaxClients", 10) == 0) {
1696 debug = ap_exists_config_define("DEBUG");
1699 no_detach = one_process = 1;
1702 one_process = ap_exists_config_define("ONE_PROCESS");
1703 no_detach = ap_exists_config_define("NO_DETACH");
1706 /* sigh, want this only the second time around */
1707 if (restart_num++ == 1) {
1711 rv = apr_proc_detach(no_detach ? APR_PROC_DETACH_FOREGROUND
1712 : APR_PROC_DETACH_DAEMONIZE);
1713 if (rv != APR_SUCCESS) {
1714 ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL,
1715 "apr_proc_detach failed");
1716 return HTTP_INTERNAL_SERVER_ERROR;
1719 parent_pid = ap_my_pid = getpid();
1722 unixd_pre_config(ptemp);
1723 ap_listen_pre_config();
1724 ap_daemons_to_start = DEFAULT_START_DAEMON;
1725 min_spare_threads = DEFAULT_MIN_FREE_DAEMON * DEFAULT_THREADS_PER_CHILD;
1726 max_spare_threads = DEFAULT_MAX_FREE_DAEMON * DEFAULT_THREADS_PER_CHILD;
1727 ap_daemons_limit = server_limit;
1728 ap_threads_per_child = DEFAULT_THREADS_PER_CHILD;
1729 ap_pid_fname = DEFAULT_PIDLOG;
1730 ap_lock_fname = DEFAULT_LOCKFILE;
1731 ap_max_requests_per_child = DEFAULT_MAX_REQUESTS_PER_CHILD;
1732 ap_extended_status = 0;
1734 apr_cpystrn(ap_coredump_dir, ap_server_root, sizeof(ap_coredump_dir));
1739 static void worker_hooks(apr_pool_t *p)
1741 /* The worker open_logs phase must run before the core's, or stderr
1742 * will be redirected to a file, and the messages won't print to the
1745 static const char *const aszSucc[] = {"core.c", NULL};
1748 ap_hook_open_logs(worker_open_logs, NULL, aszSucc, APR_HOOK_MIDDLE);
1749 ap_hook_pre_config(worker_pre_config, NULL, NULL, APR_HOOK_MIDDLE);
1752 static const char *set_daemons_to_start(cmd_parms *cmd, void *dummy,
1755 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1760 ap_daemons_to_start = atoi(arg);
1764 static const char *set_min_spare_threads(cmd_parms *cmd, void *dummy,
1767 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1772 min_spare_threads = atoi(arg);
1773 if (min_spare_threads <= 0) {
1774 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1775 "WARNING: detected MinSpareThreads set to non-positive.");
1776 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1777 "Resetting to 1 to avoid almost certain Apache failure.");
1778 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1779 "Please read the documentation.");
1780 min_spare_threads = 1;
1786 static const char *set_max_spare_threads(cmd_parms *cmd, void *dummy,
1789 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1794 max_spare_threads = atoi(arg);
1798 static const char *set_max_clients (cmd_parms *cmd, void *dummy,
1802 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1807 /* It is ok to use ap_threads_per_child here because we are
1808 * sure that it gets set before MaxClients in the pre_config stage. */
1809 max_clients = atoi(arg);
1810 if (max_clients < ap_threads_per_child) {
1811 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1812 "WARNING: MaxClients (%d) must be at least as large",
1814 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1815 " large as ThreadsPerChild (%d). Automatically",
1816 ap_threads_per_child);
1817 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1818 " increasing MaxClients to %d.",
1819 ap_threads_per_child);
1820 max_clients = ap_threads_per_child;
1822 ap_daemons_limit = max_clients / ap_threads_per_child;
1823 if ((max_clients > 0) && (max_clients % ap_threads_per_child)) {
1824 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1825 "WARNING: MaxClients (%d) is not an integer multiple",
1827 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1828 " of ThreadsPerChild (%d), lowering MaxClients to %d",
1829 ap_threads_per_child,
1830 ap_daemons_limit * ap_threads_per_child);
1831 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1832 " for a maximum of %d child processes,",
1834 max_clients = ap_daemons_limit * ap_threads_per_child;
1836 if (ap_daemons_limit > server_limit) {
1837 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1838 "WARNING: MaxClients of %d would require %d servers,",
1839 max_clients, ap_daemons_limit);
1840 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1841 " and would exceed the ServerLimit value of %d.",
1843 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1844 " Automatically lowering MaxClients to %d. To increase,",
1846 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1847 " please see the ServerLimit directive.");
1848 ap_daemons_limit = server_limit;
1850 else if (ap_daemons_limit < 1) {
1851 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1852 "WARNING: Require MaxClients > 0, setting to 1");
1853 ap_daemons_limit = 1;
1858 static const char *set_threads_per_child (cmd_parms *cmd, void *dummy,
1861 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1866 ap_threads_per_child = atoi(arg);
1867 if (ap_threads_per_child > thread_limit) {
1868 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1869 "WARNING: ThreadsPerChild of %d exceeds ThreadLimit "
1870 "value of %d", ap_threads_per_child,
1872 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1873 "threads, lowering ThreadsPerChild to %d. To increase, please"
1874 " see the", thread_limit);
1875 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1876 " ThreadLimit directive.");
1877 ap_threads_per_child = thread_limit;
1879 else if (ap_threads_per_child < 1) {
1880 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1881 "WARNING: Require ThreadsPerChild > 0, setting to 1");
1882 ap_threads_per_child = 1;
1887 static const char *set_server_limit (cmd_parms *cmd, void *dummy, const char *arg)
1889 int tmp_server_limit;
1891 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1896 tmp_server_limit = atoi(arg);
1897 /* you cannot change ServerLimit across a restart; ignore
1900 if (first_server_limit &&
1901 tmp_server_limit != server_limit) {
1902 /* how do we log a message? the error log is a bit bucket at this
1903 * point; we'll just have to set a flag so that ap_mpm_run()
1904 * logs a warning later
1906 changed_limit_at_restart = 1;
1909 server_limit = tmp_server_limit;
1911 if (server_limit > MAX_SERVER_LIMIT) {
1912 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1913 "WARNING: ServerLimit of %d exceeds compile time limit "
1914 "of %d servers,", server_limit, MAX_SERVER_LIMIT);
1915 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1916 " lowering ServerLimit to %d.", MAX_SERVER_LIMIT);
1917 server_limit = MAX_SERVER_LIMIT;
1919 else if (server_limit < 1) {
1920 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1921 "WARNING: Require ServerLimit > 0, setting to 1");
1927 static const char *set_thread_limit (cmd_parms *cmd, void *dummy, const char *arg)
1929 int tmp_thread_limit;
1931 const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
1936 tmp_thread_limit = atoi(arg);
1937 /* you cannot change ThreadLimit across a restart; ignore
1940 if (first_thread_limit &&
1941 tmp_thread_limit != thread_limit) {
1942 /* how do we log a message? the error log is a bit bucket at this
1943 * point; we'll just have to set a flag so that ap_mpm_run()
1944 * logs a warning later
1946 changed_limit_at_restart = 1;
1949 thread_limit = tmp_thread_limit;
1951 if (thread_limit > MAX_THREAD_LIMIT) {
1952 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1953 "WARNING: ThreadLimit of %d exceeds compile time limit "
1954 "of %d servers,", thread_limit, MAX_THREAD_LIMIT);
1955 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1956 " lowering ThreadLimit to %d.", MAX_THREAD_LIMIT);
1957 thread_limit = MAX_THREAD_LIMIT;
1959 else if (thread_limit < 1) {
1960 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
1961 "WARNING: Require ThreadLimit > 0, setting to 1");
1967 static const command_rec worker_cmds[] = {
1968 UNIX_DAEMON_COMMANDS,
1970 AP_INIT_TAKE1("StartServers", set_daemons_to_start, NULL, RSRC_CONF,
1971 "Number of child processes launched at server startup"),
1972 AP_INIT_TAKE1("MinSpareThreads", set_min_spare_threads, NULL, RSRC_CONF,
1973 "Minimum number of idle children, to handle request spikes"),
1974 AP_INIT_TAKE1("MaxSpareThreads", set_max_spare_threads, NULL, RSRC_CONF,
1975 "Maximum number of idle children"),
1976 AP_INIT_TAKE1("MaxClients", set_max_clients, NULL, RSRC_CONF,
1977 "Maximum number of children alive at the same time"),
1978 AP_INIT_TAKE1("ThreadsPerChild", set_threads_per_child, NULL, RSRC_CONF,
1979 "Number of threads each child creates"),
1980 AP_INIT_TAKE1("ServerLimit", set_server_limit, NULL, RSRC_CONF,
1981 "Maximum value of MaxClients for this run of Apache"),
1982 AP_INIT_TAKE1("ThreadLimit", set_thread_limit, NULL, RSRC_CONF,
1983 "Maximum worker threads in a server for this run of Apache"),
1987 module AP_MODULE_DECLARE_DATA mpm_worker_module = {
1989 NULL, /* hook to run before apache parses args */
1990 NULL, /* create per-directory config structure */
1991 NULL, /* merge per-directory config structures */
1992 NULL, /* create per-server config structure */
1993 NULL, /* merge per-server config structures */
1994 worker_cmds, /* command apr_table_t */
1995 worker_hooks /* register_hooks */