/* Copyright 1999-2004 The Apache Software Foundation * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include "apr.h" #include "apr_portable.h" #include "apr_strings.h" #include "apr_thread_proc.h" #include "apr_signal.h" #define APR_WANT_STDIO #define APR_WANT_STRFUNC #include "apr_want.h" #if APR_HAVE_UNISTD_H #include #endif #if APR_HAVE_SYS_TYPES_H #include #endif #define CORE_PRIVATE #include "ap_config.h" #include "httpd.h" #include "mpm_default.h" #include "http_main.h" #include "http_log.h" #include "http_config.h" #include "http_core.h" /* for get_remote_host */ #include "http_connection.h" #include "scoreboard.h" #include "ap_mpm.h" #include "unixd.h" #include "mpm_common.h" #include "ap_listen.h" #include "ap_mmn.h" #include "apr_poll.h" #ifdef HAVE_BSTRING_H #include /* for IRIX, FD_SET calls bzero() */ #endif #ifdef HAVE_TIME_H #include #endif #ifdef HAVE_SYS_PROCESSOR_H #include /* for bindprocessor() */ #endif #include #include /* Limit on the total --- clients will be locked out if more servers than * this are needed. It is intended solely to keep the server from crashing * when things get out of hand. * * We keep a hard maximum number of servers, for two reasons --- first off, * in case something goes seriously wrong, we want to stop the fork bomb * short of actually crashing the machine we're running on by filling some * kernel table. Secondly, it keeps the size of the scoreboard file small * enough that we can read the whole thing without worrying too much about * the overhead. */ #ifndef DEFAULT_SERVER_LIMIT #define DEFAULT_SERVER_LIMIT 256 #endif /* Admin can't tune ServerLimit beyond MAX_SERVER_LIMIT. We want * some sort of compile-time limit to help catch typos. */ #ifndef MAX_SERVER_LIMIT #define MAX_SERVER_LIMIT 20000 #endif #ifndef HARD_THREAD_LIMIT #define HARD_THREAD_LIMIT 1 #endif /* config globals */ int ap_threads_per_child=0; /* Worker threads per child */ static apr_proc_mutex_t *accept_mutex; static int ap_daemons_to_start=0; static int ap_daemons_min_free=0; static int ap_daemons_max_free=0; static int ap_daemons_limit=0; /* MaxClients */ static int server_limit = DEFAULT_SERVER_LIMIT; static int first_server_limit; static int changed_limit_at_restart; static int mpm_state = AP_MPMQ_STARTING; static ap_pod_t *pod; /* * The max child slot ever assigned, preserved across restarts. Necessary * to deal with MaxClients changes across AP_SIG_GRACEFUL restarts. We * use this value to optimize routines that have to scan the entire scoreboard. */ int ap_max_daemons_limit = -1; server_rec *ap_server_conf; /* one_process --- debugging mode variable; can be set from the command line * with the -X flag. If set, this gets you the child_main loop running * in the process which originally started up (no detach, no make_child), * which is a pretty nice debugging environment. (You'll get a SIGHUP * early in standalone_main; just continue through. This is the server * trying to kill off any child processes which it might have lying * around --- Apache doesn't keep track of their pids, it just sends * SIGHUP to the process group, ignoring it in the root process. * Continue through and you'll be fine.). */ static int one_process = 0; static apr_pool_t *pconf; /* Pool for config stuff */ static apr_pool_t *pchild; /* Pool for httpd child stuff */ static pid_t ap_my_pid; /* it seems silly to call getpid all the time */ static pid_t parent_pid; #ifndef MULTITHREAD static int my_child_num; #endif ap_generation_t volatile ap_my_generation=0; #ifdef TPF int tpf_child = 0; char tpf_server_name[INETD_SERVNAME_LENGTH+1]; #endif /* TPF */ static int die_now = 0; #ifdef GPROF /* * change directory for gprof to plop the gmon.out file * configure in httpd.conf: * GprofDir $RuntimeDir/ -> $ServerRoot/$RuntimeDir/gmon.out * GprofDir $RuntimeDir/% -> $ServerRoot/$RuntimeDir/gprof.$pid/gmon.out */ static void chdir_for_gprof(void) { core_server_config *sconf = ap_get_module_config(ap_server_conf->module_config, &core_module); char *dir = sconf->gprof_dir; const char *use_dir; if(dir) { apr_status_t res; char buf[512]; int len = strlen(sconf->gprof_dir) - 1; if(*(dir + len) == '%') { dir[len] = '\0'; apr_snprintf(buf, sizeof(buf), "%sgprof.%d", dir, (int)getpid()); } use_dir = ap_server_root_relative(pconf, buf[0] ? buf : dir); res = apr_dir_make(use_dir, 0755, pconf); if(res != APR_SUCCESS && !APR_STATUS_IS_EEXIST(res)) { ap_log_error(APLOG_MARK, APLOG_ERR, errno, ap_server_conf, "gprof: error creating directory %s", dir); } } else { use_dir = ap_server_root_relative(pconf, DEFAULT_REL_RUNTIMEDIR); } chdir(use_dir); } #else #define chdir_for_gprof() #endif /* XXX - I don't know if TPF will ever use this module or not, so leave * the ap_check_signals calls in but disable them - manoj */ #define ap_check_signals() /* a clean exit from a child with proper cleanup */ static void clean_child_exit(int code) __attribute__ ((noreturn)); static void clean_child_exit(int code) { mpm_state = AP_MPMQ_STOPPING; if (pchild) { apr_pool_destroy(pchild); } ap_mpm_pod_close(pod); chdir_for_gprof(); exit(code); } static void accept_mutex_on(void) { apr_status_t rv = apr_proc_mutex_lock(accept_mutex); if (rv != APR_SUCCESS) { const char *msg = "couldn't grab the accept mutex"; if (ap_my_generation != ap_scoreboard_image->global->running_generation) { ap_log_error(APLOG_MARK, APLOG_DEBUG, rv, NULL, msg); clean_child_exit(0); } else { ap_log_error(APLOG_MARK, APLOG_EMERG, rv, NULL, msg); exit(APEXIT_CHILDFATAL); } } } static void accept_mutex_off(void) { apr_status_t rv = apr_proc_mutex_unlock(accept_mutex); if (rv != APR_SUCCESS) { const char *msg = "couldn't release the accept mutex"; if (ap_my_generation != ap_scoreboard_image->global->running_generation) { ap_log_error(APLOG_MARK, APLOG_DEBUG, rv, NULL, msg); /* don't exit here... we have a connection to * process, after which point we'll see that the * generation changed and we'll exit cleanly */ } else { ap_log_error(APLOG_MARK, APLOG_EMERG, rv, NULL, msg); exit(APEXIT_CHILDFATAL); } } } /* On some architectures it's safe to do unserialized accept()s in the single * Listen case. But it's never safe to do it in the case where there's * multiple Listen statements. Define SINGLE_LISTEN_UNSERIALIZED_ACCEPT * when it's safe in the single Listen case. */ #ifdef SINGLE_LISTEN_UNSERIALIZED_ACCEPT #define SAFE_ACCEPT(stmt) do {if (ap_listeners->next) {stmt;}} while(0) #else #define SAFE_ACCEPT(stmt) do {stmt;} while(0) #endif AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result) { switch(query_code){ case AP_MPMQ_MAX_DAEMON_USED: *result = ap_daemons_limit; return APR_SUCCESS; case AP_MPMQ_IS_THREADED: *result = AP_MPMQ_NOT_SUPPORTED; return APR_SUCCESS; case AP_MPMQ_IS_FORKED: *result = AP_MPMQ_DYNAMIC; return APR_SUCCESS; case AP_MPMQ_HARD_LIMIT_DAEMONS: *result = server_limit; return APR_SUCCESS; case AP_MPMQ_HARD_LIMIT_THREADS: *result = HARD_THREAD_LIMIT; return APR_SUCCESS; case AP_MPMQ_MAX_THREADS: *result = 0; return APR_SUCCESS; case AP_MPMQ_MIN_SPARE_DAEMONS: *result = ap_daemons_min_free; return APR_SUCCESS; case AP_MPMQ_MIN_SPARE_THREADS: *result = 0; return APR_SUCCESS; case AP_MPMQ_MAX_SPARE_DAEMONS: *result = ap_daemons_max_free; return APR_SUCCESS; case AP_MPMQ_MAX_SPARE_THREADS: *result = 0; return APR_SUCCESS; case AP_MPMQ_MAX_REQUESTS_DAEMON: *result = ap_max_requests_per_child; return APR_SUCCESS; case AP_MPMQ_MAX_DAEMONS: *result = server_limit; return APR_SUCCESS; case AP_MPMQ_MPM_STATE: *result = mpm_state; return APR_SUCCESS; } return APR_ENOTIMPL; } #if defined(NEED_WAITPID) /* Systems without a real waitpid sometimes lose a child's exit while waiting for another. Search through the scoreboard for missing children. */ int reap_children(int *exitcode, apr_exit_why_e *status) { int n, pid; for (n = 0; n < ap_max_daemons_limit; ++n) { if (ap_scoreboard_image->servers[n][0].status != SERVER_DEAD && kill((pid = ap_scoreboard_image->parent[n].pid), 0) == -1) { ap_update_child_status_from_indexes(n, 0, SERVER_DEAD, NULL); /* just mark it as having a successful exit status */ *status = APR_PROC_EXIT; *exitcode = 0; return(pid); } } return 0; } #endif /***************************************************************** * Connection structures and accounting... */ static void just_die(int sig) { clean_child_exit(0); } /* volatile just in case */ static int volatile shutdown_pending; static int volatile restart_pending; static int volatile is_graceful; static void sig_term(int sig) { if (shutdown_pending == 1) { /* Um, is this _probably_ not an error, if the user has * tried to do a shutdown twice quickly, so we won't * worry about reporting it. */ return; } shutdown_pending = 1; } /* restart() is the signal handler for SIGHUP and AP_SIG_GRACEFUL * in the parent process, unless running in ONE_PROCESS mode */ static void restart(int sig) { if (restart_pending == 1) { /* Probably not an error - don't bother reporting it */ return; } restart_pending = 1; is_graceful = (sig == AP_SIG_GRACEFUL); } static void set_signals(void) { #ifndef NO_USE_SIGACTION struct sigaction sa; #endif if (!one_process) { ap_fatal_signal_setup(ap_server_conf, pconf); } #ifndef NO_USE_SIGACTION sigemptyset(&sa.sa_mask); sa.sa_flags = 0; sa.sa_handler = sig_term; if (sigaction(SIGTERM, &sa, NULL) < 0) ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGTERM)"); #ifdef SIGINT if (sigaction(SIGINT, &sa, NULL) < 0) ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGINT)"); #endif #ifdef SIGXCPU sa.sa_handler = SIG_DFL; if (sigaction(SIGXCPU, &sa, NULL) < 0) ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGXCPU)"); #endif #ifdef SIGXFSZ sa.sa_handler = SIG_DFL; if (sigaction(SIGXFSZ, &sa, NULL) < 0) ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGXFSZ)"); #endif #ifdef SIGPIPE sa.sa_handler = SIG_IGN; if (sigaction(SIGPIPE, &sa, NULL) < 0) ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGPIPE)"); #endif /* we want to ignore HUPs and AP_SIG_GRACEFUL while we're busy * processing one */ sigaddset(&sa.sa_mask, SIGHUP); sigaddset(&sa.sa_mask, AP_SIG_GRACEFUL); sa.sa_handler = restart; if (sigaction(SIGHUP, &sa, NULL) < 0) ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGHUP)"); if (sigaction(AP_SIG_GRACEFUL, &sa, NULL) < 0) ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(" AP_SIG_GRACEFUL_STRING ")"); #else if (!one_process) { #ifdef SIGXCPU apr_signal(SIGXCPU, SIG_DFL); #endif /* SIGXCPU */ #ifdef SIGXFSZ apr_signal(SIGXFSZ, SIG_DFL); #endif /* SIGXFSZ */ } apr_signal(SIGTERM, sig_term); #ifdef SIGHUP apr_signal(SIGHUP, restart); #endif /* SIGHUP */ #ifdef AP_SIG_GRACEFUL apr_signal(AP_SIG_GRACEFUL, restart); #endif /* AP_SIG_GRACEFUL */ #ifdef SIGPIPE apr_signal(SIGPIPE, SIG_IGN); #endif /* SIGPIPE */ #endif } /***************************************************************** * Child process main loop. * The following vars are static to avoid getting clobbered by longjmp(); * they are really private to child_main. */ static int requests_this_child; static int num_listensocks = 0; static ap_listen_rec *listensocks; int ap_graceful_stop_signalled(void) { /* not ever called anymore... */ return 0; } static void child_main(int child_num_arg) { apr_pool_t *ptrans; apr_allocator_t *allocator; conn_rec *current_conn; apr_status_t status = APR_EINIT; int i; ap_listen_rec *lr; int curr_pollfd, last_pollfd = 0; apr_pollfd_t *pollset; int offset; void *csd; ap_sb_handle_t *sbh; apr_status_t rv; apr_bucket_alloc_t *bucket_alloc; mpm_state = AP_MPMQ_STARTING; /* for benefit of any hooks that run as this * child initializes */ my_child_num = child_num_arg; ap_my_pid = getpid(); csd = NULL; requests_this_child = 0; ap_fatal_signal_child_setup(ap_server_conf); /* Get a sub context for global allocations in this child, so that * we can have cleanups occur when the child exits. */ apr_allocator_create(&allocator); apr_allocator_max_free_set(allocator, ap_max_mem_free); apr_pool_create_ex(&pchild, pconf, NULL, allocator); apr_allocator_owner_set(allocator, pchild); apr_pool_create(&ptrans, pchild); apr_pool_tag(ptrans, "transaction"); /* needs to be done before we switch UIDs so we have permissions */ ap_reopen_scoreboard(pchild, NULL, 0); rv = apr_proc_mutex_child_init(&accept_mutex, ap_lock_fname, pchild); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, "Couldn't initialize cross-process lock in child"); clean_child_exit(APEXIT_CHILDFATAL); } if (unixd_setup_child()) { clean_child_exit(APEXIT_CHILDFATAL); } ap_run_child_init(pchild, ap_server_conf); ap_create_sb_handle(&sbh, pchild, my_child_num, 0); (void) ap_update_child_status(sbh, SERVER_READY, (request_rec *) NULL); /* Set up the pollfd array */ listensocks = apr_pcalloc(pchild, sizeof(*listensocks) * (num_listensocks)); for (lr = ap_listeners, i = 0; i < num_listensocks; lr = lr->next, i++) { listensocks[i].accept_func = lr->accept_func; listensocks[i].sd = lr->sd; } pollset = apr_palloc(pchild, sizeof(*pollset) * num_listensocks); pollset[0].p = pchild; for (i = 0; i < num_listensocks; i++) { pollset[i].desc.s = listensocks[i].sd; pollset[i].desc_type = APR_POLL_SOCKET; pollset[i].reqevents = APR_POLLIN; } mpm_state = AP_MPMQ_RUNNING; bucket_alloc = apr_bucket_alloc_create(pchild); while (!die_now) { /* * (Re)initialize this child to a pre-connection state. */ current_conn = NULL; apr_pool_clear(ptrans); if ((ap_max_requests_per_child > 0 && requests_this_child++ >= ap_max_requests_per_child)) { clean_child_exit(0); } (void) ap_update_child_status(sbh, SERVER_READY, (request_rec *) NULL); /* * Wait for an acceptable connection to arrive. */ /* Lock around "accept", if necessary */ SAFE_ACCEPT(accept_mutex_on()); if (num_listensocks == 1) { offset = 0; } else { /* multiple listening sockets - need to poll */ for (;;) { apr_status_t ret; apr_int32_t n; ret = apr_poll(pollset, num_listensocks, &n, -1); if (ret != APR_SUCCESS) { if (APR_STATUS_IS_EINTR(ret)) { continue; } /* Single Unix documents select as returning errnos * EBADF, EINTR, and EINVAL... and in none of those * cases does it make sense to continue. In fact * on Linux 2.0.x we seem to end up with EFAULT * occasionally, and we'd loop forever due to it. */ ap_log_error(APLOG_MARK, APLOG_ERR, ret, ap_server_conf, "apr_poll: (listen)"); clean_child_exit(1); } /* find a listener */ curr_pollfd = last_pollfd; do { curr_pollfd++; if (curr_pollfd >= num_listensocks) { curr_pollfd = 0; } /* XXX: Should we check for POLLERR? */ if (pollset[curr_pollfd].rtnevents & APR_POLLIN) { last_pollfd = curr_pollfd; offset = curr_pollfd; goto got_fd; } } while (curr_pollfd != last_pollfd); continue; } } got_fd: /* if we accept() something we don't want to die, so we have to * defer the exit */ status = listensocks[offset].accept_func(&csd, &listensocks[offset], ptrans); SAFE_ACCEPT(accept_mutex_off()); /* unlock after "accept" */ if (status == APR_EGENERAL) { /* resource shortage or should-not-occur occured */ clean_child_exit(1); } else if (status != APR_SUCCESS) { continue; } /* * We now have a connection, so set it up with the appropriate * socket options, file descriptors, and read/write buffers. */ current_conn = ap_run_create_connection(ptrans, ap_server_conf, csd, my_child_num, sbh, bucket_alloc); if (current_conn) { ap_process_connection(current_conn, csd); ap_lingering_close(current_conn); } /* Check the pod and the generation number after processing a * connection so that we'll go away if a graceful restart occurred * while we were processing the connection or we are the lucky * idle server process that gets to die. */ if (ap_mpm_pod_check(pod) == APR_SUCCESS) { /* selected as idle? */ die_now = 1; } else if (ap_my_generation != ap_scoreboard_image->global->running_generation) { /* restart? */ /* yeah, this could be non-graceful restart, in which case the * parent will kill us soon enough, but why bother checking? */ die_now = 1; } } clean_child_exit(0); } static int make_child(server_rec *s, int slot) { int pid; if (slot + 1 > ap_max_daemons_limit) { ap_max_daemons_limit = slot + 1; } if (one_process) { apr_signal(SIGHUP, just_die); /* Don't catch AP_SIG_GRACEFUL in ONE_PROCESS mode :) */ apr_signal(SIGINT, just_die); #ifdef SIGQUIT apr_signal(SIGQUIT, SIG_DFL); #endif apr_signal(SIGTERM, just_die); child_main(slot); } (void) ap_update_child_status_from_indexes(slot, 0, SERVER_STARTING, (request_rec *) NULL); #ifdef _OSD_POSIX /* BS2000 requires a "special" version of fork() before a setuid() call */ if ((pid = os_fork(unixd_config.user_name)) == -1) { #elif defined(TPF) if ((pid = os_fork(s, slot)) == -1) { #else if ((pid = fork()) == -1) { #endif ap_log_error(APLOG_MARK, APLOG_ERR, errno, s, "fork: Unable to fork new process"); /* fork didn't succeed. Fix the scoreboard or else * it will say SERVER_STARTING forever and ever */ (void) ap_update_child_status_from_indexes(slot, 0, SERVER_DEAD, (request_rec *) NULL); /* In case system resources are maxxed out, we don't want Apache running away with the CPU trying to fork over and over and over again. */ sleep(10); return -1; } if (!pid) { #ifdef HAVE_BINDPROCESSOR /* by default AIX binds to a single processor * this bit unbinds children which will then bind to another cpu */ int status = bindprocessor(BINDPROCESS, (int)getpid(), PROCESSOR_CLASS_ANY); if (status != OK) { ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "processor unbind failed %d", status); } #endif RAISE_SIGSTOP(MAKE_CHILD); AP_MONCONTROL(1); /* Disable the parent's signal handlers and set up proper handling in * the child. */ apr_signal(SIGHUP, just_die); apr_signal(SIGTERM, just_die); /* The child process doesn't do anything for AP_SIG_GRACEFUL. * Instead, the pod is used for signalling graceful restart. */ apr_signal(AP_SIG_GRACEFUL, SIG_IGN); child_main(slot); } ap_scoreboard_image->parent[slot].pid = pid; return 0; } /* start up a bunch of children */ static void startup_children(int number_to_start) { int i; for (i = 0; number_to_start && i < ap_daemons_limit; ++i) { if (ap_scoreboard_image->servers[i][0].status != SERVER_DEAD) { continue; } if (make_child(ap_server_conf, i) < 0) { break; } --number_to_start; } } /* * idle_spawn_rate is the number of children that will be spawned on the * next maintenance cycle if there aren't enough idle servers. It is * doubled up to MAX_SPAWN_RATE, and reset only when a cycle goes by * without the need to spawn. */ static int idle_spawn_rate = 1; #ifndef MAX_SPAWN_RATE #define MAX_SPAWN_RATE (32) #endif static int hold_off_on_exponential_spawning; static void perform_idle_server_maintenance(apr_pool_t *p) { int i; int to_kill; int idle_count; worker_score *ws; int free_length; int free_slots[MAX_SPAWN_RATE]; int last_non_dead; int total_non_dead; /* initialize the free_list */ free_length = 0; to_kill = -1; idle_count = 0; last_non_dead = -1; total_non_dead = 0; for (i = 0; i < ap_daemons_limit; ++i) { int status; if (i >= ap_max_daemons_limit && free_length == idle_spawn_rate) break; ws = &ap_scoreboard_image->servers[i][0]; status = ws->status; if (status == SERVER_DEAD) { /* try to keep children numbers as low as possible */ if (free_length < idle_spawn_rate) { free_slots[free_length] = i; ++free_length; } } else { /* We consider a starting server as idle because we started it * at least a cycle ago, and if it still hasn't finished starting * then we're just going to swamp things worse by forking more. * So we hopefully won't need to fork more if we count it. * This depends on the ordering of SERVER_READY and SERVER_STARTING. */ if (status <= SERVER_READY) { ++ idle_count; /* always kill the highest numbered child if we have to... * no really well thought out reason ... other than observing * the server behaviour under linux where lower numbered children * tend to service more hits (and hence are more likely to have * their data in cpu caches). */ to_kill = i; } ++total_non_dead; last_non_dead = i; } } ap_max_daemons_limit = last_non_dead + 1; if (idle_count > ap_daemons_max_free) { /* kill off one child... we use the pod because that'll cause it to * shut down gracefully, in case it happened to pick up a request * while we were counting */ ap_mpm_pod_signal(pod); idle_spawn_rate = 1; } else if (idle_count < ap_daemons_min_free) { /* terminate the free list */ if (free_length == 0) { /* only report this condition once */ static int reported = 0; if (!reported) { ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, "server reached MaxClients setting, consider" " raising the MaxClients setting"); reported = 1; } idle_spawn_rate = 1; } else { if (idle_spawn_rate >= 8) { ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf, "server seems busy, (you may need " "to increase StartServers, or Min/MaxSpareServers), " "spawning %d children, there are %d idle, and " "%d total children", idle_spawn_rate, idle_count, total_non_dead); } for (i = 0; i < free_length; ++i) { #ifdef TPF if (make_child(ap_server_conf, free_slots[i]) == -1) { if(free_length == 1) { shutdown_pending = 1; ap_log_error(APLOG_MARK, APLOG_EMERG, 0, ap_server_conf, "No active child processes: shutting down"); } } #else make_child(ap_server_conf, free_slots[i]); #endif /* TPF */ } /* the next time around we want to spawn twice as many if this * wasn't good enough, but not if we've just done a graceful */ if (hold_off_on_exponential_spawning) { --hold_off_on_exponential_spawning; } else if (idle_spawn_rate < MAX_SPAWN_RATE) { idle_spawn_rate *= 2; } } } else { idle_spawn_rate = 1; } } /***************************************************************** * Executive routines. */ int ap_mpm_run(apr_pool_t *_pconf, apr_pool_t *plog, server_rec *s) { int index; int remaining_children_to_start; apr_status_t rv; ap_log_pid(pconf, ap_pid_fname); first_server_limit = server_limit; if (changed_limit_at_restart) { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, "WARNING: Attempt to change ServerLimit " "ignored during restart"); changed_limit_at_restart = 0; } /* Initialize cross-process accept lock */ ap_lock_fname = apr_psprintf(_pconf, "%s.%" APR_PID_T_FMT, ap_server_root_relative(_pconf, ap_lock_fname), ap_my_pid); rv = apr_proc_mutex_create(&accept_mutex, ap_lock_fname, ap_accept_lock_mech, _pconf); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "Couldn't create accept lock"); mpm_state = AP_MPMQ_STOPPING; return 1; } #if APR_USE_SYSVSEM_SERIALIZE if (ap_accept_lock_mech == APR_LOCK_DEFAULT || ap_accept_lock_mech == APR_LOCK_SYSVSEM) { #else if (ap_accept_lock_mech == APR_LOCK_SYSVSEM) { #endif rv = unixd_set_proc_mutex_perms(accept_mutex); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "Couldn't set permissions on cross-process lock; " "check User and Group directives"); mpm_state = AP_MPMQ_STOPPING; return 1; } } if (!is_graceful) { if (ap_run_pre_mpm(s->process->pool, SB_SHARED) != OK) { mpm_state = AP_MPMQ_STOPPING; return 1; } /* fix the generation number in the global score; we just got a new, * cleared scoreboard */ ap_scoreboard_image->global->running_generation = ap_my_generation; } set_signals(); if (one_process) { AP_MONCONTROL(1); } if (ap_daemons_max_free < ap_daemons_min_free + 1) /* Don't thrash... */ ap_daemons_max_free = ap_daemons_min_free + 1; /* If we're doing a graceful_restart then we're going to see a lot * of children exiting immediately when we get into the main loop * below (because we just sent them AP_SIG_GRACEFUL). This happens pretty * rapidly... and for each one that exits we'll start a new one until * we reach at least daemons_min_free. But we may be permitted to * start more than that, so we'll just keep track of how many we're * supposed to start up without the 1 second penalty between each fork. */ remaining_children_to_start = ap_daemons_to_start; if (remaining_children_to_start > ap_daemons_limit) { remaining_children_to_start = ap_daemons_limit; } if (!is_graceful) { startup_children(remaining_children_to_start); remaining_children_to_start = 0; } else { /* give the system some time to recover before kicking into * exponential mode */ hold_off_on_exponential_spawning = 10; } ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, "%s configured -- resuming normal operations", ap_get_server_version()); ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf, "Server built: %s", ap_get_server_built()); #ifdef AP_MPM_WANT_SET_ACCEPT_LOCK_MECH ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, "AcceptMutex: %s (default: %s)", apr_proc_mutex_name(accept_mutex), apr_proc_mutex_defname()); #endif restart_pending = shutdown_pending = 0; mpm_state = AP_MPMQ_RUNNING; while (!restart_pending && !shutdown_pending) { int child_slot; apr_exit_why_e exitwhy; int status, processed_status; /* this is a memory leak, but I'll fix it later. */ apr_proc_t pid; ap_wait_or_timeout(&exitwhy, &status, &pid, pconf); /* XXX: if it takes longer than 1 second for all our children * to start up and get into IDLE state then we may spawn an * extra child */ if (pid.pid != -1) { processed_status = ap_process_child_status(&pid, exitwhy, status); if (processed_status == APEXIT_CHILDFATAL) { mpm_state = AP_MPMQ_STOPPING; return 1; } /* non-fatal death... note that it's gone in the scoreboard. */ child_slot = find_child_by_pid(&pid); if (child_slot >= 0) { (void) ap_update_child_status_from_indexes(child_slot, 0, SERVER_DEAD, (request_rec *) NULL); if (processed_status == APEXIT_CHILDSICK) { /* child detected a resource shortage (E[NM]FILE, ENOBUFS, etc) * cut the fork rate to the minimum */ idle_spawn_rate = 1; } else if (remaining_children_to_start && child_slot < ap_daemons_limit) { /* we're still doing a 1-for-1 replacement of dead * children with new children */ make_child(ap_server_conf, child_slot); --remaining_children_to_start; } #if APR_HAS_OTHER_CHILD } else if (apr_proc_other_child_read(&pid, status) == 0) { /* handled */ #endif } else if (is_graceful) { /* Great, we've probably just lost a slot in the * scoreboard. Somehow we don't know about this * child. */ ap_log_error(APLOG_MARK, APLOG_WARNING, 0, ap_server_conf, "long lost child came home! (pid %ld)", (long)pid.pid); } /* Don't perform idle maintenance when a child dies, * only do it when there's a timeout. Remember only a * finite number of children can die, and it's pretty * pathological for a lot to die suddenly. */ continue; } else if (remaining_children_to_start) { /* we hit a 1 second timeout in which none of the previous * generation of children needed to be reaped... so assume * they're all done, and pick up the slack if any is left. */ startup_children(remaining_children_to_start); remaining_children_to_start = 0; /* In any event we really shouldn't do the code below because * few of the servers we just started are in the IDLE state * yet, so we'd mistakenly create an extra server. */ continue; } perform_idle_server_maintenance(pconf); #ifdef TPF shutdown_pending = os_check_server(tpf_server_name); ap_check_signals(); sleep(1); #endif /*TPF */ } mpm_state = AP_MPMQ_STOPPING; if (shutdown_pending) { /* Time to gracefully shut down: * Kill child processes, tell them to call child_exit, etc... */ if (unixd_killpg(getpgrp(), SIGTERM) < 0) { ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "killpg SIGTERM"); } ap_reclaim_child_processes(1); /* Start with SIGTERM */ /* cleanup pid file on normal shutdown */ { const char *pidfile = NULL; pidfile = ap_server_root_relative (pconf, ap_pid_fname); if ( pidfile != NULL && unlink(pidfile) == 0) ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf, "removed PID file %s (pid=%ld)", pidfile, (long)getpid()); } ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, "caught SIGTERM, shutting down"); return 1; } /* we've been told to restart */ apr_signal(SIGHUP, SIG_IGN); if (one_process) { /* not worth thinking about */ return 1; } /* advance to the next generation */ /* XXX: we really need to make sure this new generation number isn't in * use by any of the children. */ ++ap_my_generation; ap_scoreboard_image->global->running_generation = ap_my_generation; if (is_graceful) { ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, "Graceful restart requested, doing restart"); /* kill off the idle ones */ ap_mpm_pod_killpg(pod, ap_max_daemons_limit); /* This is mostly for debugging... so that we know what is still * gracefully dealing with existing request. This will break * in a very nasty way if we ever have the scoreboard totally * file-based (no shared memory) */ for (index = 0; index < ap_daemons_limit; ++index) { if (ap_scoreboard_image->servers[index][0].status != SERVER_DEAD) { ap_scoreboard_image->servers[index][0].status = SERVER_GRACEFUL; } } } else { /* Kill 'em off */ if (unixd_killpg(getpgrp(), SIGHUP) < 0) { ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "killpg SIGHUP"); } ap_reclaim_child_processes(0); /* Not when just starting up */ ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, "SIGHUP received. Attempting to restart"); } return 0; } /* This really should be a post_config hook, but the error log is already * redirected by that point, so we need to do this in the open_logs phase. */ static int prefork_open_logs(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s) { apr_status_t rv; pconf = p; ap_server_conf = s; if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) { ap_log_error(APLOG_MARK, APLOG_ALERT|APLOG_STARTUP, 0, NULL, "no listening sockets available, shutting down"); return DONE; } if ((rv = ap_mpm_pod_open(pconf, &pod))) { ap_log_error(APLOG_MARK, APLOG_CRIT|APLOG_STARTUP, rv, NULL, "Could not open pipe-of-death."); return DONE; } return OK; } static int prefork_pre_config(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp) { static int restart_num = 0; int no_detach, debug, foreground; apr_status_t rv; mpm_state = AP_MPMQ_STARTING; debug = ap_exists_config_define("DEBUG"); if (debug) { foreground = one_process = 1; no_detach = 0; } else { no_detach = ap_exists_config_define("NO_DETACH"); one_process = ap_exists_config_define("ONE_PROCESS"); foreground = ap_exists_config_define("FOREGROUND"); } /* sigh, want this only the second time around */ if (restart_num++ == 1) { is_graceful = 0; if (!one_process && !foreground) { rv = apr_proc_detach(no_detach ? APR_PROC_DETACH_FOREGROUND : APR_PROC_DETACH_DAEMONIZE); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL, "apr_proc_detach failed"); return HTTP_INTERNAL_SERVER_ERROR; } } parent_pid = ap_my_pid = getpid(); } unixd_pre_config(ptemp); ap_listen_pre_config(); ap_daemons_to_start = DEFAULT_START_DAEMON; ap_daemons_min_free = DEFAULT_MIN_FREE_DAEMON; ap_daemons_max_free = DEFAULT_MAX_FREE_DAEMON; ap_daemons_limit = server_limit; ap_pid_fname = DEFAULT_PIDLOG; ap_lock_fname = DEFAULT_LOCKFILE; ap_max_requests_per_child = DEFAULT_MAX_REQUESTS_PER_CHILD; ap_extended_status = 0; #ifdef AP_MPM_WANT_SET_MAX_MEM_FREE ap_max_mem_free = APR_ALLOCATOR_MAX_FREE_UNLIMITED; #endif apr_cpystrn(ap_coredump_dir, ap_server_root, sizeof(ap_coredump_dir)); return OK; } static void prefork_hooks(apr_pool_t *p) { /* The prefork open_logs phase must run before the core's, or stderr * will be redirected to a file, and the messages won't print to the * console. */ static const char *const aszSucc[] = {"core.c", NULL}; #ifdef AUX3 (void) set42sig(); #endif ap_hook_open_logs(prefork_open_logs, NULL, aszSucc, APR_HOOK_MIDDLE); /* we need to set the MPM state before other pre-config hooks use MPM query * to retrieve it, so register as REALLY_FIRST */ ap_hook_pre_config(prefork_pre_config, NULL, NULL, APR_HOOK_REALLY_FIRST); } static const char *set_daemons_to_start(cmd_parms *cmd, void *dummy, const char *arg) { const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } ap_daemons_to_start = atoi(arg); return NULL; } static const char *set_min_free_servers(cmd_parms *cmd, void *dummy, const char *arg) { const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } ap_daemons_min_free = atoi(arg); if (ap_daemons_min_free <= 0) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: detected MinSpareServers set to non-positive."); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "Resetting to 1 to avoid almost certain Apache failure."); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "Please read the documentation."); ap_daemons_min_free = 1; } return NULL; } static const char *set_max_free_servers(cmd_parms *cmd, void *dummy, const char *arg) { const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } ap_daemons_max_free = atoi(arg); return NULL; } static const char *set_max_clients (cmd_parms *cmd, void *dummy, const char *arg) { const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } ap_daemons_limit = atoi(arg); if (ap_daemons_limit > server_limit) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: MaxClients of %d exceeds ServerLimit value " "of %d servers,", ap_daemons_limit, server_limit); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, " lowering MaxClients to %d. To increase, please " "see the ServerLimit", server_limit); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, " directive."); ap_daemons_limit = server_limit; } else if (ap_daemons_limit < 1) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: Require MaxClients > 0, setting to 1"); ap_daemons_limit = 1; } return NULL; } static const char *set_server_limit (cmd_parms *cmd, void *dummy, const char *arg) { int tmp_server_limit; const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } tmp_server_limit = atoi(arg); /* you cannot change ServerLimit across a restart; ignore * any such attempts */ if (first_server_limit && tmp_server_limit != server_limit) { /* how do we log a message? the error log is a bit bucket at this * point; we'll just have to set a flag so that ap_mpm_run() * logs a warning later */ changed_limit_at_restart = 1; return NULL; } server_limit = tmp_server_limit; if (server_limit > MAX_SERVER_LIMIT) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: ServerLimit of %d exceeds compile time limit " "of %d servers,", server_limit, MAX_SERVER_LIMIT); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, " lowering ServerLimit to %d.", MAX_SERVER_LIMIT); server_limit = MAX_SERVER_LIMIT; } else if (server_limit < 1) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: Require ServerLimit > 0, setting to 1"); server_limit = 1; } return NULL; } static const command_rec prefork_cmds[] = { UNIX_DAEMON_COMMANDS, LISTEN_COMMANDS, AP_INIT_TAKE1("StartServers", set_daemons_to_start, NULL, RSRC_CONF, "Number of child processes launched at server startup"), AP_INIT_TAKE1("MinSpareServers", set_min_free_servers, NULL, RSRC_CONF, "Minimum number of idle children, to handle request spikes"), AP_INIT_TAKE1("MaxSpareServers", set_max_free_servers, NULL, RSRC_CONF, "Maximum number of idle children"), AP_INIT_TAKE1("MaxClients", set_max_clients, NULL, RSRC_CONF, "Maximum number of children alive at the same time"), AP_INIT_TAKE1("ServerLimit", set_server_limit, NULL, RSRC_CONF, "Maximum value of MaxClients for this run of Apache"), { NULL } }; module AP_MODULE_DECLARE_DATA mpm_prefork_module = { MPM20_MODULE_STUFF, ap_mpm_rewrite_args, /* hook to run before apache parses args */ NULL, /* create per-directory config structure */ NULL, /* merge per-directory config structures */ NULL, /* create per-server config structure */ NULL, /* merge per-server config structures */ prefork_cmds, /* command apr_table_t */ prefork_hooks, /* register hooks */ };