/* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 #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 "util_mutex.h" #include "unixd.h" #include "mpm_common.h" #include "ap_listen.h" #include "ap_mmn.h" #include "apr_poll.h" #include #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 200000 #endif #ifndef HARD_THREAD_LIMIT #define HARD_THREAD_LIMIT 1 #endif /* config globals */ 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; /* MaxRequestWorkers */ static int server_limit = 0; /* data retained by prefork across load/unload of the module * allocated on first call to pre-config hook; located on * subsequent calls to pre-config hook */ typedef struct prefork_retained_data { ap_unixd_mpm_retained_data *mpm; int first_server_limit; int maxclients_reported; /* * The max child slot ever assigned, preserved across restarts. Necessary * to deal with MaxRequestWorkers changes across AP_SIG_GRACEFUL restarts. We * use this value to optimize routines that have to scan the entire scoreboard. */ int max_daemons_limit; /* * 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. */ int idle_spawn_rate; #ifndef MAX_SPAWN_RATE #define MAX_SPAWN_RATE (32) #endif int hold_off_on_exponential_spawning; } prefork_retained_data; static prefork_retained_data *retained; typedef struct prefork_child_bucket { ap_pod_t *pod; ap_listen_rec *listeners; apr_proc_mutex_t *mutex; } prefork_child_bucket; static prefork_child_bucket *all_buckets, /* All listeners buckets */ *my_bucket; /* Current child bucket */ #define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid) /* 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; static int my_child_num; #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_core_module_config(ap_server_conf->module_config); char *dir = sconf->gprof_dir; const char *use_dir; if(dir) { apr_status_t res; char *buf = NULL ; int len = strlen(sconf->gprof_dir) - 1; if(*(dir + len) == '%') { dir[len] = '\0'; buf = ap_append_pid(pconf, dir, "gprof."); } use_dir = ap_server_root_relative(pconf, buf ? buf : dir); res = apr_dir_make(use_dir, APR_UREAD | APR_UWRITE | APR_UEXECUTE | APR_GREAD | APR_GEXECUTE | APR_WREAD | APR_WEXECUTE, pconf); if(res != APR_SUCCESS && !APR_STATUS_IS_EEXIST(res)) { ap_log_error(APLOG_MARK, APLOG_ERR, res, ap_server_conf, APLOGNO(00142) "gprof: error creating directory %s", dir); } } else { use_dir = ap_runtime_dir_relative(pconf, ""); } chdir(use_dir); } #else #define chdir_for_gprof() #endif static void prefork_note_child_killed(int childnum, pid_t pid, ap_generation_t gen) { AP_DEBUG_ASSERT(childnum != -1); /* no scoreboard squatting with this MPM */ ap_run_child_status(ap_server_conf, ap_scoreboard_image->parent[childnum].pid, ap_scoreboard_image->parent[childnum].generation, childnum, MPM_CHILD_EXITED); ap_scoreboard_image->parent[childnum].pid = 0; } static void prefork_note_child_started(int slot, pid_t pid) { ap_generation_t gen = retained->mpm->my_generation; ap_scoreboard_image->parent[slot].pid = pid; ap_scoreboard_image->parent[slot].generation = gen; ap_run_child_status(ap_server_conf, pid, gen, slot, MPM_CHILD_STARTED); } /* 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) { retained->mpm->mpm_state = AP_MPMQ_STOPPING; apr_signal(SIGHUP, SIG_IGN); apr_signal(SIGTERM, SIG_IGN); if (pchild) { apr_pool_destroy(pchild); } if (one_process) { prefork_note_child_killed(/* slot */ 0, 0, 0); } ap_mpm_pod_close(my_bucket->pod); chdir_for_gprof(); exit(code); } static apr_status_t accept_mutex_on(void) { apr_status_t rv = apr_proc_mutex_lock(my_bucket->mutex); if (rv != APR_SUCCESS) { const char *msg = "couldn't grab the accept mutex"; if (retained->mpm->my_generation != ap_scoreboard_image->global->running_generation) { ap_log_error(APLOG_MARK, APLOG_DEBUG, rv, ap_server_conf, APLOGNO(00143) "%s", msg); clean_child_exit(0); } else { ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(00144) "%s", msg); exit(APEXIT_CHILDFATAL); } } return APR_SUCCESS; } static apr_status_t accept_mutex_off(void) { apr_status_t rv = apr_proc_mutex_unlock(my_bucket->mutex); if (rv != APR_SUCCESS) { const char *msg = "couldn't release the accept mutex"; if (retained->mpm->my_generation != ap_scoreboard_image->global->running_generation) { ap_log_error(APLOG_MARK, APLOG_DEBUG, rv, ap_server_conf, APLOGNO(00145) "%s", 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, ap_server_conf, APLOGNO(00146) "%s", msg); exit(APEXIT_CHILDFATAL); } } return APR_SUCCESS; } /* 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) (ap_listeners->next ? (stmt) : APR_SUCCESS) #else #define SAFE_ACCEPT(stmt) (stmt) #endif static int prefork_query(int query_code, int *result, apr_status_t *rv) { *rv = APR_SUCCESS; switch(query_code){ case AP_MPMQ_MAX_DAEMON_USED: *result = ap_daemons_limit; break; case AP_MPMQ_IS_THREADED: *result = AP_MPMQ_NOT_SUPPORTED; break; case AP_MPMQ_IS_FORKED: *result = AP_MPMQ_DYNAMIC; break; case AP_MPMQ_HARD_LIMIT_DAEMONS: *result = server_limit; break; case AP_MPMQ_HARD_LIMIT_THREADS: *result = HARD_THREAD_LIMIT; break; case AP_MPMQ_MAX_THREADS: *result = 1; break; case AP_MPMQ_MIN_SPARE_DAEMONS: *result = ap_daemons_min_free; break; case AP_MPMQ_MIN_SPARE_THREADS: *result = 0; break; case AP_MPMQ_MAX_SPARE_DAEMONS: *result = ap_daemons_max_free; break; case AP_MPMQ_MAX_SPARE_THREADS: *result = 0; break; case AP_MPMQ_MAX_REQUESTS_DAEMON: *result = ap_max_requests_per_child; break; case AP_MPMQ_MAX_DAEMONS: *result = ap_daemons_limit; break; case AP_MPMQ_MPM_STATE: *result = retained->mpm->mpm_state; break; case AP_MPMQ_GENERATION: *result = retained->mpm->my_generation; break; default: *rv = APR_ENOTIMPL; break; } return OK; } static const char *prefork_get_name(void) { return "prefork"; } /***************************************************************** * Connection structures and accounting... */ static void just_die(int sig) { clean_child_exit(0); } /* volatile because it's updated from a signal handler */ static int volatile die_now = 0; static void stop_listening(int sig) { retained->mpm->mpm_state = AP_MPMQ_STOPPING; ap_close_listeners_ex(my_bucket->listeners); /* For a graceful stop, we want the child to exit when done */ die_now = 1; } /***************************************************************** * 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 void child_main(int child_num_arg, int child_bucket) { #if APR_HAS_THREADS apr_thread_t *thd = NULL; apr_os_thread_t osthd; #endif apr_pool_t *ptrans; apr_allocator_t *allocator; apr_status_t status; int i; ap_listen_rec *lr; apr_pollset_t *pollset; ap_sb_handle_t *sbh; apr_bucket_alloc_t *bucket_alloc; int last_poll_idx = 0; const char *lockfile; /* for benefit of any hooks that run as this child initializes */ retained->mpm->mpm_state = AP_MPMQ_STARTING; my_child_num = child_num_arg; ap_my_pid = getpid(); 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_tag(pchild, "pchild"); #if APR_HAS_THREADS osthd = apr_os_thread_current(); apr_os_thread_put(&thd, &osthd, pchild); #endif apr_pool_create(&ptrans, pchild); apr_pool_tag(ptrans, "transaction"); /* close unused listeners and pods */ for (i = 0; i < retained->mpm->num_buckets; i++) { if (i != child_bucket) { ap_close_listeners_ex(all_buckets[i].listeners); ap_mpm_pod_close(all_buckets[i].pod); } } /* needs to be done before we switch UIDs so we have permissions */ ap_reopen_scoreboard(pchild, NULL, 0); status = SAFE_ACCEPT(apr_proc_mutex_child_init(&my_bucket->mutex, apr_proc_mutex_lockfile(my_bucket->mutex), pchild)); if (status != APR_SUCCESS) { lockfile = apr_proc_mutex_lockfile(my_bucket->mutex); ap_log_error(APLOG_MARK, APLOG_EMERG, status, ap_server_conf, APLOGNO(00155) "Couldn't initialize cross-process lock in child " "(%s) (%s)", lockfile ? lockfile : "none", apr_proc_mutex_name(my_bucket->mutex)); clean_child_exit(APEXIT_CHILDFATAL); } if (ap_run_drop_privileges(pchild, ap_server_conf)) { 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 */ status = apr_pollset_create(&pollset, num_listensocks, pchild, APR_POLLSET_NOCOPY); if (status != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_EMERG, status, ap_server_conf, APLOGNO(00156) "Couldn't create pollset in child; check system or user limits"); clean_child_exit(APEXIT_CHILDSICK); /* assume temporary resource issue */ } for (lr = my_bucket->listeners, i = num_listensocks; i--; lr = lr->next) { apr_pollfd_t *pfd = apr_pcalloc(pchild, sizeof *pfd); pfd->desc_type = APR_POLL_SOCKET; pfd->desc.s = lr->sd; pfd->reqevents = APR_POLLIN; pfd->client_data = lr; status = apr_pollset_add(pollset, pfd); if (status != APR_SUCCESS) { /* If the child processed a SIGWINCH before setting up the * pollset, this error path is expected and harmless, * since the listener fd was already closed; so don't * pollute the logs in that case. */ if (!die_now) { ap_log_error(APLOG_MARK, APLOG_EMERG, status, ap_server_conf, APLOGNO(00157) "Couldn't add listener to pollset; check system or user limits"); clean_child_exit(APEXIT_CHILDSICK); } clean_child_exit(0); } lr->accept_func = ap_unixd_accept; } retained->mpm->mpm_state = AP_MPMQ_RUNNING; bucket_alloc = apr_bucket_alloc_create(pchild); /* die_now is set when AP_SIG_GRACEFUL is received in the child; * {shutdown,restart}_pending are set when a signal is received while * running in single process mode. */ while (!die_now && !retained->mpm->shutdown_pending && !retained->mpm->restart_pending) { conn_rec *current_conn; void *csd; /* * (Re)initialize this child to a pre-connection state. */ 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) { /* There is only one listener record, so refer to that one. */ lr = my_bucket->listeners; } else { /* multiple listening sockets - need to poll */ for (;;) { apr_int32_t numdesc; const apr_pollfd_t *pdesc; /* check for termination first so we don't sleep for a while in * poll if already signalled */ if (die_now /* in graceful stop/restart */ || retained->mpm->shutdown_pending || retained->mpm->restart_pending) { SAFE_ACCEPT(accept_mutex_off()); clean_child_exit(0); } /* timeout == 10 seconds to avoid a hang at graceful restart/stop * caused by the closing of sockets by the signal handler */ status = apr_pollset_poll(pollset, apr_time_from_sec(10), &numdesc, &pdesc); if (status != APR_SUCCESS) { if (APR_STATUS_IS_TIMEUP(status) || APR_STATUS_IS_EINTR(status)) { 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, status, ap_server_conf, APLOGNO(00158) "apr_pollset_poll: (listen)"); SAFE_ACCEPT(accept_mutex_off()); clean_child_exit(APEXIT_CHILDSICK); } /* We can always use pdesc[0], but sockets at position N * could end up completely starved of attention in a very * busy server. Therefore, we round-robin across the * returned set of descriptors. While it is possible that * the returned set of descriptors might flip around and * continue to starve some sockets, we happen to know the * internal pollset implementation retains ordering * stability of the sockets. Thus, the round-robin should * ensure that a socket will eventually be serviced. */ if (last_poll_idx >= numdesc) last_poll_idx = 0; /* Grab a listener record from the client_data of the poll * descriptor, and advance our saved index to round-robin * the next fetch. * * ### hmm... this descriptor might have POLLERR rather * ### than POLLIN */ lr = pdesc[last_poll_idx++].client_data; goto got_fd; } } got_fd: /* if we accept() something we don't want to die, so we have to * defer the exit */ status = lr->accept_func(&csd, lr, ptrans); SAFE_ACCEPT(accept_mutex_off()); /* unlock after "accept" */ if (status == APR_EGENERAL) { /* resource shortage or should-not-occur occurred */ clean_child_exit(APEXIT_CHILDSICK); } 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) { #if APR_HAS_THREADS current_conn->current_thread = thd; #endif 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(my_bucket->pod) == APR_SUCCESS) { /* selected as idle? */ die_now = 1; } else if (retained->mpm->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; } } apr_pool_clear(ptrans); /* kludge to avoid crash in APR reslist cleanup code */ clean_child_exit(0); } static int make_child(server_rec *s, int slot, int bucket) { int pid; if (slot + 1 > retained->max_daemons_limit) { retained->max_daemons_limit = slot + 1; } if (one_process) { my_bucket = &all_buckets[0]; prefork_note_child_started(slot, getpid()); child_main(slot, 0); /* NOTREACHED */ ap_assert(0); return -1; } (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(ap_unixd_config.user_name)) == -1) { #else if ((pid = fork()) == -1) { #endif ap_log_error(APLOG_MARK, APLOG_ERR, errno, s, APLOGNO(00159) "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) { my_bucket = &all_buckets[bucket]; #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_DEBUG, errno, ap_server_conf, APLOGNO(00160) "processor unbind failed"); } #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); /* Ignore SIGINT in child. This fixes race-condition in signals * handling when httpd is runnning on foreground and user hits ctrl+c. * In this case, SIGINT is sent to all children followed by SIGTERM * from the main process, which interrupts the SIGINT handler and * leads to inconsistency. */ apr_signal(SIGINT, SIG_IGN); /* The child process just closes listeners on AP_SIG_GRACEFUL. * The pod is used for signalling the graceful restart. */ apr_signal(AP_SIG_GRACEFUL, stop_listening); child_main(slot, bucket); } ap_scoreboard_image->parent[slot].bucket = bucket; prefork_note_child_started(slot, 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, i % retained->mpm->num_buckets) < 0) { break; } --number_to_start; } } static void perform_idle_server_maintenance(apr_pool_t *p) { static int bucket_make_child_record = -1; static int bucket_kill_child_record = -1; int i; 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; idle_count = 0; last_non_dead = -1; total_non_dead = 0; for (i = 0; i < ap_daemons_limit; ++i) { int status; if (i >= retained->max_daemons_limit && free_length == retained->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 < retained->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; } ++total_non_dead; last_non_dead = i; } } retained->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 */ bucket_kill_child_record = (bucket_kill_child_record + 1) % retained->mpm->num_buckets; ap_mpm_pod_signal(all_buckets[bucket_kill_child_record].pod); retained->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 */ if (!retained->maxclients_reported) { ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(00161) "server reached MaxRequestWorkers setting, consider" " raising the MaxRequestWorkers setting"); retained->maxclients_reported = 1; } retained->idle_spawn_rate = 1; } else { if (retained->idle_spawn_rate >= 8) { ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf, APLOGNO(00162) "server seems busy, (you may need " "to increase StartServers, or Min/MaxSpareServers), " "spawning %d children, there are %d idle, and " "%d total children", retained->idle_spawn_rate, idle_count, total_non_dead); } for (i = 0; i < free_length; ++i) { bucket_make_child_record++; bucket_make_child_record %= retained->mpm->num_buckets; make_child(ap_server_conf, free_slots[i], bucket_make_child_record); } /* 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 (retained->hold_off_on_exponential_spawning) { --retained->hold_off_on_exponential_spawning; } else if (retained->idle_spawn_rate < MAX_SPAWN_RATE) { retained->idle_spawn_rate *= 2; } } } else { retained->idle_spawn_rate = 1; } } /***************************************************************** * Executive routines. */ static int prefork_run(apr_pool_t *_pconf, apr_pool_t *plog, server_rec *s) { int index; int remaining_children_to_start; int i; ap_log_pid(pconf, ap_pid_fname); if (!retained->mpm->was_graceful) { if (ap_run_pre_mpm(s->process->pool, SB_SHARED) != OK) { retained->mpm->mpm_state = AP_MPMQ_STOPPING; return !OK; } /* fix the generation number in the global score; we just got a new, * cleared scoreboard */ ap_scoreboard_image->global->running_generation = retained->mpm->my_generation; } ap_unixd_mpm_set_signals(pconf, one_process); if (one_process) { AP_MONCONTROL(1); make_child(ap_server_conf, 0, 0); /* NOTREACHED */ ap_assert(0); return !OK; } /* Don't thrash since num_buckets depends on the * system and the number of online CPU cores... */ if (ap_daemons_limit < retained->mpm->num_buckets) ap_daemons_limit = retained->mpm->num_buckets; if (ap_daemons_to_start < retained->mpm->num_buckets) ap_daemons_to_start = retained->mpm->num_buckets; if (ap_daemons_min_free < retained->mpm->num_buckets) ap_daemons_min_free = retained->mpm->num_buckets; if (ap_daemons_max_free < ap_daemons_min_free + retained->mpm->num_buckets) ap_daemons_max_free = ap_daemons_min_free + retained->mpm->num_buckets; /* 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 (!retained->mpm->was_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 */ retained->hold_off_on_exponential_spawning = 10; } ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00163) "%s configured -- resuming normal operations", ap_get_server_description()); ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf, APLOGNO(00164) "Server built: %s", ap_get_server_built()); ap_log_command_line(plog, s); ap_log_mpm_common(s); ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00165) "Accept mutex: %s (default: %s)", (all_buckets[0].mutex) ? apr_proc_mutex_name(all_buckets[0].mutex) : "none", apr_proc_mutex_defname()); retained->mpm->mpm_state = AP_MPMQ_RUNNING; while (!retained->mpm->restart_pending && !retained->mpm->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, ap_server_conf); /* 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); child_slot = ap_find_child_by_pid(&pid); if (processed_status == APEXIT_CHILDFATAL) { /* fix race condition found in PR 39311 * A child created at the same time as a graceful happens * can find the lock missing and create a fatal error. * It is not fatal for the last generation to be in this state. */ if (child_slot < 0 || ap_get_scoreboard_process(child_slot)->generation == retained->mpm->my_generation) { retained->mpm->mpm_state = AP_MPMQ_STOPPING; return !OK; } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, ap_server_conf, APLOGNO(00166) "Ignoring fatal error in child of previous " "generation (pid %ld).", (long)pid.pid); } } /* non-fatal death... note that it's gone in the scoreboard. */ if (child_slot >= 0) { (void) ap_update_child_status_from_indexes(child_slot, 0, SERVER_DEAD, (request_rec *) NULL); prefork_note_child_killed(child_slot, 0, 0); if (processed_status == APEXIT_CHILDSICK) { /* child detected a resource shortage (E[NM]FILE, ENOBUFS, etc) * cut the fork rate to the minimum */ retained->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, ap_get_scoreboard_process(child_slot)->bucket); --remaining_children_to_start; } #if APR_HAS_OTHER_CHILD } else if (apr_proc_other_child_alert(&pid, APR_OC_REASON_DEATH, status) == APR_SUCCESS) { /* handled */ #endif } else if (retained->mpm->was_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, APLOGNO(00167) "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); } retained->mpm->mpm_state = AP_MPMQ_STOPPING; if (retained->mpm->shutdown_pending && retained->mpm->is_ungraceful) { /* Time to shut down: * Kill child processes, tell them to call child_exit, etc... */ if (ap_unixd_killpg(getpgrp(), SIGTERM) < 0) { ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, APLOGNO(00168) "killpg SIGTERM"); } ap_reclaim_child_processes(1, /* Start with SIGTERM */ prefork_note_child_killed); /* cleanup pid file on normal shutdown */ ap_remove_pid(pconf, ap_pid_fname); ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00169) "caught SIGTERM, shutting down"); return DONE; } if (retained->mpm->shutdown_pending) { /* Time to perform a graceful shut down: * Reap the inactive children, and ask the active ones * to close their listeners, then wait until they are * all done to exit. */ int active_children; apr_time_t cutoff = 0; /* Stop listening */ ap_close_listeners(); /* kill off the idle ones */ for (i = 0; i < retained->mpm->num_buckets; i++) { ap_mpm_pod_killpg(all_buckets[i].pod, retained->max_daemons_limit); } /* Send SIGUSR1 to the active children */ active_children = 0; for (index = 0; index < ap_daemons_limit; ++index) { if (ap_scoreboard_image->servers[index][0].status != SERVER_DEAD) { /* Ask each child to close its listeners. */ ap_mpm_safe_kill(MPM_CHILD_PID(index), AP_SIG_GRACEFUL); active_children++; } } /* Allow each child which actually finished to exit */ ap_relieve_child_processes(prefork_note_child_killed); /* cleanup pid file */ ap_remove_pid(pconf, ap_pid_fname); ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00170) "caught " AP_SIG_GRACEFUL_STOP_STRING ", shutting down gracefully"); if (ap_graceful_shutdown_timeout) { cutoff = apr_time_now() + apr_time_from_sec(ap_graceful_shutdown_timeout); } /* Don't really exit until each child has finished */ retained->mpm->shutdown_pending = 0; do { /* Pause for a second */ sleep(1); /* Relieve any children which have now exited */ ap_relieve_child_processes(prefork_note_child_killed); active_children = 0; for (index = 0; index < ap_daemons_limit; ++index) { if (ap_mpm_safe_kill(MPM_CHILD_PID(index), 0) == APR_SUCCESS) { active_children = 1; /* Having just one child is enough to stay around */ break; } } } while (!retained->mpm->shutdown_pending && active_children && (!ap_graceful_shutdown_timeout || apr_time_now() < cutoff)); /* We might be here because we received SIGTERM, either * way, try and make sure that all of our processes are * really dead. */ ap_unixd_killpg(getpgrp(), SIGTERM); return DONE; } /* we've been told to restart */ if (one_process) { /* not worth thinking about */ return DONE; } /* 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. */ ++retained->mpm->my_generation; ap_scoreboard_image->global->running_generation = retained->mpm->my_generation; if (!retained->mpm->is_ungraceful) { ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00171) "Graceful restart requested, doing restart"); /* kill off the idle ones */ for (i = 0; i < retained->mpm->num_buckets; i++) { ap_mpm_pod_killpg(all_buckets[i].pod, retained->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; /* Ask each child to close its listeners. * * NOTE: we use the scoreboard, because if we send SIGUSR1 * to every process in the group, this may include CGI's, * piped loggers, etc. They almost certainly won't handle * it gracefully. */ ap_mpm_safe_kill(ap_scoreboard_image->parent[index].pid, AP_SIG_GRACEFUL); } } } else { /* Kill 'em off */ if (ap_unixd_killpg(getpgrp(), SIGHUP) < 0) { ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, APLOGNO(00172) "killpg SIGHUP"); } ap_reclaim_child_processes(0, /* Not when just starting up */ prefork_note_child_killed); ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00173) "SIGHUP received. Attempting to restart"); } return OK; } /* 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) { int startup = 0; int level_flags = 0; ap_listen_rec **listen_buckets; apr_status_t rv; char id[16]; int i; pconf = p; /* the reverse of pre_config, we want this only the first time around */ if (retained->mpm->module_loads == 1) { startup = 1; level_flags |= APLOG_STARTUP; } if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) { ap_log_error(APLOG_MARK, APLOG_ALERT | level_flags, 0, (startup ? NULL : s), "no listening sockets available, shutting down"); return !OK; } if (one_process) { retained->mpm->num_buckets = 1; } else if (!retained->mpm->was_graceful) { /* Preserve the number of buckets on graceful restarts. */ retained->mpm->num_buckets = 0; } if ((rv = ap_duplicate_listeners(pconf, ap_server_conf, &listen_buckets, &retained->mpm->num_buckets))) { ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv, (startup ? NULL : s), "could not duplicate listeners"); return !OK; } all_buckets = apr_pcalloc(pconf, retained->mpm->num_buckets * sizeof(prefork_child_bucket)); for (i = 0; i < retained->mpm->num_buckets; i++) { if ((rv = ap_mpm_pod_open(pconf, &all_buckets[i].pod))) { ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv, (startup ? NULL : s), "could not open pipe-of-death"); return !OK; } /* Initialize cross-process accept lock (safe accept needed only) */ if ((rv = SAFE_ACCEPT((apr_snprintf(id, sizeof id, "%i", i), ap_proc_mutex_create(&all_buckets[i].mutex, NULL, AP_ACCEPT_MUTEX_TYPE, id, s, pconf, 0))))) { ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv, (startup ? NULL : s), "could not create accept mutex"); return !OK; } all_buckets[i].listeners = listen_buckets[i]; } return OK; } static int prefork_pre_config(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp) { int no_detach, debug, foreground; apr_status_t rv; const char *userdata_key = "mpm_prefork_module"; 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"); } ap_mutex_register(p, AP_ACCEPT_MUTEX_TYPE, NULL, APR_LOCK_DEFAULT, 0); retained = ap_retained_data_get(userdata_key); if (!retained) { retained = ap_retained_data_create(userdata_key, sizeof(*retained)); retained->mpm = ap_unixd_mpm_get_retained_data(); retained->max_daemons_limit = -1; retained->idle_spawn_rate = 1; } retained->mpm->mpm_state = AP_MPMQ_STARTING; if (retained->mpm->baton != retained) { retained->mpm->was_graceful = 0; retained->mpm->baton = retained; } ++retained->mpm->module_loads; /* sigh, want this only the second time around */ if (retained->mpm->module_loads == 2) { if (!one_process && !foreground) { /* before we detach, setup crash handlers to log to errorlog */ ap_fatal_signal_setup(ap_server_conf, pconf); 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, APLOGNO(00174) "apr_proc_detach failed"); return HTTP_INTERNAL_SERVER_ERROR; } } } parent_pid = ap_my_pid = getpid(); 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; server_limit = DEFAULT_SERVER_LIMIT; ap_daemons_limit = server_limit; ap_extended_status = 0; return OK; } static int prefork_check_config(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s) { int startup = 0; /* the reverse of pre_config, we want this only the first time around */ if (retained->mpm->module_loads == 1) { startup = 1; } if (server_limit > MAX_SERVER_LIMIT) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00175) "WARNING: ServerLimit of %d exceeds compile-time " "limit of %d servers, decreasing to %d.", server_limit, MAX_SERVER_LIMIT, MAX_SERVER_LIMIT); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00176) "ServerLimit of %d exceeds compile-time limit " "of %d, decreasing to match", server_limit, MAX_SERVER_LIMIT); } server_limit = MAX_SERVER_LIMIT; } else if (server_limit < 1) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00177) "WARNING: ServerLimit of %d not allowed, " "increasing to 1.", server_limit); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00178) "ServerLimit of %d not allowed, increasing to 1", server_limit); } server_limit = 1; } /* you cannot change ServerLimit across a restart; ignore * any such attempts */ if (!retained->first_server_limit) { retained->first_server_limit = server_limit; } else if (server_limit != retained->first_server_limit) { /* don't need a startup console version here */ ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00179) "changing ServerLimit to %d from original value of %d " "not allowed during restart", server_limit, retained->first_server_limit); server_limit = retained->first_server_limit; } if (ap_daemons_limit > server_limit) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00180) "WARNING: MaxRequestWorkers of %d exceeds ServerLimit " "value of %d servers, decreasing MaxRequestWorkers to %d. " "To increase, please see the ServerLimit directive.", ap_daemons_limit, server_limit, server_limit); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00181) "MaxRequestWorkers of %d exceeds ServerLimit value " "of %d, decreasing to match", ap_daemons_limit, server_limit); } ap_daemons_limit = server_limit; } else if (ap_daemons_limit < 1) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00182) "WARNING: MaxRequestWorkers of %d not allowed, " "increasing to 1.", ap_daemons_limit); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00183) "MaxRequestWorkers of %d not allowed, increasing to 1", ap_daemons_limit); } ap_daemons_limit = 1; } /* ap_daemons_to_start > ap_daemons_limit checked in prefork_run() */ if (ap_daemons_to_start < 1) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00184) "WARNING: StartServers of %d not allowed, " "increasing to 1.", ap_daemons_to_start); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00185) "StartServers of %d not allowed, increasing to 1", ap_daemons_to_start); } ap_daemons_to_start = 1; } if (ap_daemons_min_free < 1) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00186) "WARNING: MinSpareServers of %d not allowed, " "increasing to 1 to avoid almost certain server failure. " "Please read the documentation.", ap_daemons_min_free); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00187) "MinSpareServers of %d not allowed, increasing to 1", ap_daemons_min_free); } ap_daemons_min_free = 1; } /* ap_daemons_max_free < ap_daemons_min_free + 1 checked in prefork_run() */ return OK; } static void prefork_hooks(apr_pool_t *p) { /* Our open_logs hook function 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}; ap_hook_open_logs(prefork_open_logs, NULL, aszSucc, APR_HOOK_REALLY_FIRST); /* 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); ap_hook_check_config(prefork_check_config, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_mpm(prefork_run, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_mpm_query(prefork_query, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_mpm_get_name(prefork_get_name, NULL, NULL, APR_HOOK_MIDDLE); } 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); 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; } if (!strcasecmp(cmd->cmd->name, "MaxClients")) { ap_log_error(APLOG_MARK, APLOG_INFO, 0, NULL, APLOGNO(00188) "MaxClients is deprecated, use MaxRequestWorkers " "instead."); } ap_daemons_limit = atoi(arg); return NULL; } static const char *set_server_limit (cmd_parms *cmd, void *dummy, const char *arg) { const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } server_limit = atoi(arg); return NULL; } static const command_rec prefork_cmds[] = { 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, "Deprecated name of MaxRequestWorkers"), AP_INIT_TAKE1("MaxRequestWorkers", 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 MaxRequestWorkers for this run of Apache"), AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND, { NULL } }; AP_DECLARE_MODULE(mpm_prefork) = { MPM20_MODULE_STUFF, NULL, /* 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 */ };