/* 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. */ /* The purpose of this MPM is to fix the design flaws in the threaded * model. Because of the way that pthreads and mutex locks interact, * it is basically impossible to cleanly gracefully shutdown a child * process if multiple threads are all blocked in accept. This model * fixes those problems. */ #include "apr.h" #include "apr_portable.h" #include "apr_strings.h" #include "apr_file_io.h" #include "apr_thread_proc.h" #include "apr_signal.h" #include "apr_thread_mutex.h" #include "apr_proc_mutex.h" #include "apr_poll.h" #define APR_WANT_STRFUNC #include "apr_want.h" #if APR_HAVE_UNISTD_H #include <unistd.h> #endif #if APR_HAVE_SYS_SOCKET_H #include <sys/socket.h> #endif #if APR_HAVE_SYS_WAIT_H #include <sys/wait.h> #endif #ifdef HAVE_SYS_PROCESSOR_H #include <sys/processor.h> /* for bindprocessor() */ #endif #if !APR_HAS_THREADS #error The Worker MPM requires APR threads, but they are unavailable. #endif #define CORE_PRIVATE #include "ap_config.h" #include "httpd.h" #include "http_main.h" #include "http_log.h" #include "http_config.h" /* for read_config */ #include "http_core.h" /* for get_remote_host */ #include "http_connection.h" #include "ap_mpm.h" #include "pod.h" #include "mpm_common.h" #include "ap_listen.h" #include "scoreboard.h" #include "fdqueue.h" #include "mpm_default.h" #include <signal.h> #include <limits.h> /* for INT_MAX */ /* 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 16 #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 /* Limit on the threads per process. Clients will be locked out if more than * this * server_limit are needed. * * We keep this for one reason 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_THREAD_LIMIT #define DEFAULT_THREAD_LIMIT 64 #endif /* Admin can't tune ThreadLimit beyond MAX_THREAD_LIMIT. We want * some sort of compile-time limit to help catch typos. */ #ifndef MAX_THREAD_LIMIT #define MAX_THREAD_LIMIT 20000 #endif /* * Actual definitions of config globals */ int ap_threads_per_child = 0; /* Worker threads per child */ static int ap_daemons_to_start = 0; static int min_spare_threads = 0; static int max_spare_threads = 0; static int ap_daemons_limit = 0; static int server_limit = DEFAULT_SERVER_LIMIT; static int first_server_limit = 0; static int thread_limit = DEFAULT_THREAD_LIMIT; static int first_thread_limit = 0; static int changed_limit_at_restart; static int dying = 0; static int workers_may_exit = 0; static int start_thread_may_exit = 0; static int listener_may_exit = 0; static int requests_this_child; static int num_listensocks = 0; static int resource_shortage = 0; static fd_queue_t *worker_queue; static fd_queue_info_t *worker_queue_info; static int mpm_state = AP_MPMQ_STARTING; static int sick_child_detected; /* The structure used to pass unique initialization info to each thread */ typedef struct { int pid; int tid; int sd; } proc_info; /* Structure used to pass information to the thread responsible for * creating the rest of the threads. */ typedef struct { apr_thread_t **threads; apr_thread_t *listener; int child_num_arg; apr_threadattr_t *threadattr; } thread_starter; #define ID_FROM_CHILD_THREAD(c, t) ((c * thread_limit) + t) /* * 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; static ap_pod_t *pod; /* *Non*-shared http_main globals... */ server_rec *ap_server_conf; /* The worker MPM respects a couple of runtime flags that can aid * in debugging. Setting the -DNO_DETACH flag will prevent the root process * from detaching from its controlling terminal. Additionally, setting * the -DONE_PROCESS flag (which implies -DNO_DETACH) will get you the * child_main loop running in the process which originally started up. * This gives you 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; #ifdef DEBUG_SIGSTOP int raise_sigstop_flags; #endif 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; /* Linux getpid() doesn't work except in main thread. Use this instead */ static pid_t parent_pid; static apr_os_thread_t *listener_os_thread; /* Locks for accept serialization */ static apr_proc_mutex_t *accept_mutex; #ifdef SINGLE_LISTEN_UNSERIALIZED_ACCEPT #define SAFE_ACCEPT(stmt) (ap_listeners->next ? (stmt) : APR_SUCCESS) #else #define SAFE_ACCEPT(stmt) (stmt) #endif /* The LISTENER_SIGNAL signal will be sent from the main thread to the * listener thread to wake it up for graceful termination (what a child * process from an old generation does when the admin does "apachectl * graceful"). This signal will be blocked in all threads of a child * process except for the listener thread. */ #define LISTENER_SIGNAL SIGHUP /* The WORKER_SIGNAL signal will be sent from the main thread to the * worker threads during an ungraceful restart or shutdown. * This ensures that on systems (i.e., Linux) where closing the worker * socket doesn't awake the worker thread when it is polling on the socket * (especially in apr_wait_for_io_or_timeout() when handling * Keep-Alive connections), close_worker_sockets() and join_workers() * still function in timely manner and allow ungraceful shutdowns to * proceed to completion. Otherwise join_workers() doesn't return * before the main process decides the child process is non-responsive * and sends a SIGKILL. */ #define WORKER_SIGNAL AP_SIG_GRACEFUL /* An array of socket descriptors in use by each thread used to * perform a non-graceful (forced) shutdown of the server. */ static apr_socket_t **worker_sockets; static void close_worker_sockets(void) { int i; for (i = 0; i < ap_threads_per_child; i++) { if (worker_sockets[i]) { apr_socket_close(worker_sockets[i]); worker_sockets[i] = NULL; } } } static void wakeup_listener(void) { listener_may_exit = 1; if (!listener_os_thread) { /* XXX there is an obscure path that this doesn't handle perfectly: * right after listener thread is created but before * listener_os_thread is set, the first worker thread hits an * error and starts graceful termination */ return; } /* * we should just be able to "kill(ap_my_pid, LISTENER_SIGNAL)" on all * platforms and wake up the listener thread since it is the only thread * with SIGHUP unblocked, but that doesn't work on Linux */ #ifdef HAVE_PTHREAD_KILL pthread_kill(*listener_os_thread, LISTENER_SIGNAL); #else kill(ap_my_pid, LISTENER_SIGNAL); #endif } #define ST_INIT 0 #define ST_GRACEFUL 1 #define ST_UNGRACEFUL 2 static int terminate_mode = ST_INIT; static void signal_threads(int mode) { if (terminate_mode == mode) { return; } terminate_mode = mode; mpm_state = AP_MPMQ_STOPPING; /* in case we weren't called from the listener thread, wake up the * listener thread */ wakeup_listener(); /* for ungraceful termination, let the workers exit now; * for graceful termination, the listener thread will notify the * workers to exit once it has stopped accepting new connections */ if (mode == ST_UNGRACEFUL) { workers_may_exit = 1; ap_queue_interrupt_all(worker_queue); ap_queue_info_term(worker_queue_info); close_worker_sockets(); /* forcefully kill all current connections */ } } AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result) { switch(query_code){ case AP_MPMQ_MAX_DAEMON_USED: *result = ap_max_daemons_limit; return APR_SUCCESS; case AP_MPMQ_IS_THREADED: *result = AP_MPMQ_STATIC; 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 = thread_limit; return APR_SUCCESS; case AP_MPMQ_MAX_THREADS: *result = ap_threads_per_child; return APR_SUCCESS; case AP_MPMQ_MIN_SPARE_DAEMONS: *result = 0; return APR_SUCCESS; case AP_MPMQ_MIN_SPARE_THREADS: *result = min_spare_threads; return APR_SUCCESS; case AP_MPMQ_MAX_SPARE_DAEMONS: *result = 0; return APR_SUCCESS; case AP_MPMQ_MAX_SPARE_THREADS: *result = max_spare_threads; return APR_SUCCESS; case AP_MPMQ_MAX_REQUESTS_DAEMON: *result = ap_max_requests_per_child; return APR_SUCCESS; case AP_MPMQ_MAX_DAEMONS: *result = ap_daemons_limit; return APR_SUCCESS; case AP_MPMQ_MPM_STATE: *result = mpm_state; return APR_SUCCESS; } return APR_ENOTIMPL; } /* 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); } exit(code); } static void just_die(int sig) { clean_child_exit(0); } /***************************************************************** * Connection structures and accounting... */ /* volatile just in case */ static int volatile shutdown_pending; static int volatile restart_pending; static int volatile is_graceful; static volatile int child_fatal; ap_generation_t volatile ap_my_generation; /* * ap_start_shutdown() and ap_start_restart(), below, are a first stab at * functions to initiate shutdown or restart without relying on signals. * Previously this was initiated in sig_term() and restart() signal handlers, * but we want to be able to start a shutdown/restart from other sources -- * e.g. on Win32, from the service manager. Now the service manager can * call ap_start_shutdown() or ap_start_restart() as appropiate. Note that * these functions can also be called by the child processes, since global * variables are no longer used to pass on the required action to the parent. * * These should only be called from the parent process itself, since the * parent process will use the shutdown_pending and restart_pending variables * to determine whether to shutdown or restart. The child process should * call signal_parent() directly to tell the parent to die -- this will * cause neither of those variable to be set, which the parent will * assume means something serious is wrong (which it will be, for the * child to force an exit) and so do an exit anyway. */ static void ap_start_shutdown(int graceful) { mpm_state = AP_MPMQ_STOPPING; 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; is_graceful = graceful; } /* do a graceful restart if graceful == 1 */ static void ap_start_restart(int graceful) { mpm_state = AP_MPMQ_STOPPING; if (restart_pending == 1) { /* Probably not an error - don't bother reporting it */ return; } restart_pending = 1; is_graceful = graceful; } static void sig_term(int sig) { ap_start_shutdown(sig == AP_SIG_GRACEFUL_STOP); } static void restart(int sig) { ap_start_restart(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 AP_SIG_GRACEFUL_STOP if (sigaction(AP_SIG_GRACEFUL_STOP, &sa, NULL) < 0) ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(" AP_SIG_GRACEFUL_STOP_STRING ")"); #endif #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 AP_SIG_GRACEFUL_STOP apr_signal(AP_SIG_GRACEFUL_STOP, sig_term); #endif /* AP_SIG_GRACEFUL_STOP */ #ifdef SIGPIPE apr_signal(SIGPIPE, SIG_IGN); #endif /* SIGPIPE */ #endif } /***************************************************************** * Here follows a long bunch of generic server bookkeeping stuff... */ int ap_graceful_stop_signalled(void) /* XXX this is really a bad confusing obsolete name * maybe it should be ap_mpm_process_exiting? */ { /* note: for a graceful termination, listener_may_exit will be set before * workers_may_exit, so check listener_may_exit */ return listener_may_exit; } /***************************************************************** * Child process main loop. */ static void process_socket(apr_pool_t *p, apr_socket_t *sock, int my_child_num, int my_thread_num, apr_bucket_alloc_t *bucket_alloc) { conn_rec *current_conn; long conn_id = ID_FROM_CHILD_THREAD(my_child_num, my_thread_num); int csd; ap_sb_handle_t *sbh; ap_create_sb_handle(&sbh, p, my_child_num, my_thread_num); apr_os_sock_get(&csd, sock); current_conn = ap_run_create_connection(p, ap_server_conf, sock, conn_id, sbh, bucket_alloc); if (current_conn) { ap_process_connection(current_conn, sock); ap_lingering_close(current_conn); } } /* requests_this_child has gone to zero or below. See if the admin coded "MaxRequestsPerChild 0", and keep going in that case. Doing it this way simplifies the hot path in worker_thread */ static void check_infinite_requests(void) { if (ap_max_requests_per_child) { signal_threads(ST_GRACEFUL); } else { /* wow! if you're executing this code, you may have set a record. * either this child process has served over 2 billion requests, or * you're running a threaded 2.0 on a 16 bit machine. * * I'll buy pizza and beers at Apachecon for the first person to do * the former without cheating (dorking with INT_MAX, or running with * uncommitted performance patches, for example). * * for the latter case, you probably deserve a beer too. Greg Ames */ requests_this_child = INT_MAX; /* keep going */ } } static void unblock_signal(int sig) { sigset_t sig_mask; sigemptyset(&sig_mask); sigaddset(&sig_mask, sig); #if defined(SIGPROCMASK_SETS_THREAD_MASK) sigprocmask(SIG_UNBLOCK, &sig_mask, NULL); #else pthread_sigmask(SIG_UNBLOCK, &sig_mask, NULL); #endif } static void dummy_signal_handler(int sig) { /* XXX If specifying SIG_IGN is guaranteed to unblock a syscall, * then we don't need this goofy function. */ } static void *listener_thread(apr_thread_t *thd, void * dummy) { proc_info * ti = dummy; int process_slot = ti->pid; apr_pool_t *tpool = apr_thread_pool_get(thd); void *csd = NULL; apr_pool_t *ptrans = NULL; /* Pool for per-transaction stuff */ apr_pollset_t *pollset; apr_status_t rv; ap_listen_rec *lr; int have_idle_worker = 0; int last_poll_idx = 0; free(ti); /* ### check the status */ (void) apr_pollset_create(&pollset, num_listensocks, tpool, 0); for (lr = ap_listeners; lr != NULL; lr = lr->next) { apr_pollfd_t pfd = { 0 }; pfd.desc_type = APR_POLL_SOCKET; pfd.desc.s = lr->sd; pfd.reqevents = APR_POLLIN; pfd.client_data = lr; /* ### check the status */ (void) apr_pollset_add(pollset, &pfd); } /* Unblock the signal used to wake this thread up, and set a handler for * it. */ unblock_signal(LISTENER_SIGNAL); apr_signal(LISTENER_SIGNAL, dummy_signal_handler); /* TODO: Switch to a system where threads reuse the results from earlier poll calls - manoj */ while (1) { /* TODO: requests_this_child should be synchronized - aaron */ if (requests_this_child <= 0) { check_infinite_requests(); } if (listener_may_exit) break; if (!have_idle_worker) { /* the following pops a recycled ptrans pool off a stack * if there is one, in addition to reserving a worker thread */ rv = ap_queue_info_wait_for_idler(worker_queue_info, &ptrans); if (APR_STATUS_IS_EOF(rv)) { break; /* we've been signaled to die now */ } else if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, "apr_queue_info_wait failed. Attempting to " " shutdown process gracefully."); signal_threads(ST_GRACEFUL); break; } have_idle_worker = 1; } /* We've already decremented the idle worker count inside * ap_queue_info_wait_for_idler. */ if ((rv = SAFE_ACCEPT(apr_proc_mutex_lock(accept_mutex))) != APR_SUCCESS) { int level = APLOG_EMERG; if (listener_may_exit) { break; } if (ap_scoreboard_image->parent[process_slot].generation != ap_scoreboard_image->global->running_generation) { level = APLOG_DEBUG; /* common to get these at restart time */ } ap_log_error(APLOG_MARK, level, rv, ap_server_conf, "apr_proc_mutex_lock failed. Attempting to shutdown " "process gracefully."); signal_threads(ST_GRACEFUL); break; /* skip the lock release */ } if (!ap_listeners->next) { /* Only one listener, so skip the poll */ lr = ap_listeners; } else { while (!listener_may_exit) { apr_int32_t numdesc; const apr_pollfd_t *pdesc; rv = apr_pollset_poll(pollset, -1, &numdesc, &pdesc); if (rv != APR_SUCCESS) { if (APR_STATUS_IS_EINTR(rv)) { continue; } /* apr_pollset_poll() will only return errors in catastrophic * circumstances. Let's try exiting gracefully, for now. */ ap_log_error(APLOG_MARK, APLOG_ERR, rv, (const server_rec *) ap_server_conf, "apr_pollset_poll: (listen)"); signal_threads(ST_GRACEFUL); } if (listener_may_exit) break; /* 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; break; } /* while */ } /* if/else */ if (!listener_may_exit) { if (ptrans == NULL) { /* we can't use a recycled transaction pool this time. * create a new transaction pool */ apr_allocator_t *allocator; apr_allocator_create(&allocator); apr_allocator_max_free_set(allocator, ap_max_mem_free); apr_pool_create_ex(&ptrans, pconf, NULL, allocator); apr_allocator_owner_set(allocator, ptrans); } apr_pool_tag(ptrans, "transaction"); rv = lr->accept_func(&csd, lr, ptrans); /* later we trash rv and rely on csd to indicate success/failure */ AP_DEBUG_ASSERT(rv == APR_SUCCESS || !csd); if (rv == APR_EGENERAL) { /* E[NM]FILE, ENOMEM, etc */ resource_shortage = 1; signal_threads(ST_GRACEFUL); } if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(accept_mutex))) != APR_SUCCESS) { int level = APLOG_EMERG; if (listener_may_exit) { break; } if (ap_scoreboard_image->parent[process_slot].generation != ap_scoreboard_image->global->running_generation) { level = APLOG_DEBUG; /* common to get these at restart time */ } ap_log_error(APLOG_MARK, level, rv, ap_server_conf, "apr_proc_mutex_unlock failed. Attempting to " "shutdown process gracefully."); signal_threads(ST_GRACEFUL); } if (csd != NULL) { rv = ap_queue_push(worker_queue, csd, ptrans); if (rv) { /* trash the connection; we couldn't queue the connected * socket to a worker */ apr_socket_close(csd); ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, "ap_queue_push failed"); } else { have_idle_worker = 0; } } } else { if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(accept_mutex))) != APR_SUCCESS) { int level = APLOG_EMERG; if (ap_scoreboard_image->parent[process_slot].generation != ap_scoreboard_image->global->running_generation) { level = APLOG_DEBUG; /* common to get these at restart time */ } ap_log_error(APLOG_MARK, level, rv, ap_server_conf, "apr_proc_mutex_unlock failed. Attempting to " "shutdown process gracefully."); signal_threads(ST_GRACEFUL); } break; } } ap_close_listeners(); ap_queue_term(worker_queue); dying = 1; ap_scoreboard_image->parent[process_slot].quiescing = 1; /* wake up the main thread */ kill(ap_my_pid, SIGTERM); apr_thread_exit(thd, APR_SUCCESS); return NULL; } /* XXX For ungraceful termination/restart, we definitely don't want to * wait for active connections to finish but we may want to wait * for idle workers to get out of the queue code and release mutexes, * since those mutexes are cleaned up pretty soon and some systems * may not react favorably (i.e., segfault) if operations are attempted * on cleaned-up mutexes. */ static void * APR_THREAD_FUNC worker_thread(apr_thread_t *thd, void * dummy) { proc_info * ti = dummy; int process_slot = ti->pid; int thread_slot = ti->tid; apr_socket_t *csd = NULL; apr_bucket_alloc_t *bucket_alloc; apr_pool_t *last_ptrans = NULL; apr_pool_t *ptrans; /* Pool for per-transaction stuff */ apr_status_t rv; int is_idle = 0; free(ti); ap_scoreboard_image->servers[process_slot][thread_slot].pid = ap_my_pid; ap_scoreboard_image->servers[process_slot][thread_slot].generation = ap_my_generation; ap_update_child_status_from_indexes(process_slot, thread_slot, SERVER_STARTING, NULL); #ifdef HAVE_PTHREAD_KILL unblock_signal(WORKER_SIGNAL); apr_signal(WORKER_SIGNAL, dummy_signal_handler); #endif while (!workers_may_exit) { if (!is_idle) { rv = ap_queue_info_set_idle(worker_queue_info, last_ptrans); last_ptrans = NULL; if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, "ap_queue_info_set_idle failed. Attempting to " "shutdown process gracefully."); signal_threads(ST_GRACEFUL); break; } is_idle = 1; } ap_update_child_status_from_indexes(process_slot, thread_slot, SERVER_READY, NULL); worker_pop: if (workers_may_exit) { break; } rv = ap_queue_pop(worker_queue, &csd, &ptrans); if (rv != APR_SUCCESS) { /* We get APR_EOF during a graceful shutdown once all the connections * accepted by this server process have been handled. */ if (APR_STATUS_IS_EOF(rv)) { break; } /* We get APR_EINTR whenever ap_queue_pop() has been interrupted * from an explicit call to ap_queue_interrupt_all(). This allows * us to unblock threads stuck in ap_queue_pop() when a shutdown * is pending. * * If workers_may_exit is set and this is ungraceful termination/ * restart, we are bound to get an error on some systems (e.g., * AIX, which sanity-checks mutex operations) since the queue * may have already been cleaned up. Don't log the "error" if * workers_may_exit is set. */ else if (APR_STATUS_IS_EINTR(rv)) { goto worker_pop; } /* We got some other error. */ else if (!workers_may_exit) { ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, "ap_queue_pop failed"); } continue; } is_idle = 0; worker_sockets[thread_slot] = csd; bucket_alloc = apr_bucket_alloc_create(ptrans); process_socket(ptrans, csd, process_slot, thread_slot, bucket_alloc); worker_sockets[thread_slot] = NULL; requests_this_child--; /* FIXME: should be synchronized - aaron */ apr_pool_clear(ptrans); last_ptrans = ptrans; } ap_update_child_status_from_indexes(process_slot, thread_slot, (dying) ? SERVER_DEAD : SERVER_GRACEFUL, (request_rec *) NULL); apr_thread_exit(thd, APR_SUCCESS); return NULL; } static int check_signal(int signum) { switch (signum) { case SIGTERM: case SIGINT: return 1; } return 0; } static void create_listener_thread(thread_starter *ts) { int my_child_num = ts->child_num_arg; apr_threadattr_t *thread_attr = ts->threadattr; proc_info *my_info; apr_status_t rv; my_info = (proc_info *)malloc(sizeof(proc_info)); my_info->pid = my_child_num; my_info->tid = -1; /* listener thread doesn't have a thread slot */ my_info->sd = 0; rv = apr_thread_create(&ts->listener, thread_attr, listener_thread, my_info, pchild); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, "apr_thread_create: unable to create listener thread"); /* let the parent decide how bad this really is */ clean_child_exit(APEXIT_CHILDSICK); } apr_os_thread_get(&listener_os_thread, ts->listener); } /* XXX under some circumstances not understood, children can get stuck * in start_threads forever trying to take over slots which will * never be cleaned up; for now there is an APLOG_DEBUG message issued * every so often when this condition occurs */ static void * APR_THREAD_FUNC start_threads(apr_thread_t *thd, void *dummy) { thread_starter *ts = dummy; apr_thread_t **threads = ts->threads; apr_threadattr_t *thread_attr = ts->threadattr; int child_num_arg = ts->child_num_arg; int my_child_num = child_num_arg; proc_info *my_info; apr_status_t rv; int i; int threads_created = 0; int listener_started = 0; int loops; int prev_threads_created; /* We must create the fd queues before we start up the listener * and worker threads. */ worker_queue = apr_pcalloc(pchild, sizeof(*worker_queue)); rv = ap_queue_init(worker_queue, ap_threads_per_child, pchild); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, "ap_queue_init() failed"); clean_child_exit(APEXIT_CHILDFATAL); } rv = ap_queue_info_create(&worker_queue_info, pchild, ap_threads_per_child); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, "ap_queue_info_create() failed"); clean_child_exit(APEXIT_CHILDFATAL); } worker_sockets = apr_pcalloc(pchild, ap_threads_per_child * sizeof(apr_socket_t *)); loops = prev_threads_created = 0; while (1) { /* ap_threads_per_child does not include the listener thread */ for (i = 0; i < ap_threads_per_child; i++) { int status = ap_scoreboard_image->servers[child_num_arg][i].status; if (status != SERVER_GRACEFUL && status != SERVER_DEAD) { continue; } my_info = (proc_info *)malloc(sizeof(proc_info)); if (my_info == NULL) { ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf, "malloc: out of memory"); clean_child_exit(APEXIT_CHILDFATAL); } my_info->pid = my_child_num; my_info->tid = i; my_info->sd = 0; /* We are creating threads right now */ ap_update_child_status_from_indexes(my_child_num, i, SERVER_STARTING, NULL); /* We let each thread update its own scoreboard entry. This is * done because it lets us deal with tid better. */ rv = apr_thread_create(&threads[i], thread_attr, worker_thread, my_info, pchild); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, "apr_thread_create: unable to create worker thread"); /* let the parent decide how bad this really is */ clean_child_exit(APEXIT_CHILDSICK); } threads_created++; } /* Start the listener only when there are workers available */ if (!listener_started && threads_created) { create_listener_thread(ts); listener_started = 1; } if (start_thread_may_exit || threads_created == ap_threads_per_child) { break; } /* wait for previous generation to clean up an entry */ apr_sleep(apr_time_from_sec(1)); ++loops; if (loops % 120 == 0) { /* every couple of minutes */ if (prev_threads_created == threads_created) { ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, "child %" APR_PID_T_FMT " isn't taking over " "slots very quickly (%d of %d)", ap_my_pid, threads_created, ap_threads_per_child); } prev_threads_created = threads_created; } } /* What state should this child_main process be listed as in the * scoreboard...? * ap_update_child_status_from_indexes(my_child_num, i, SERVER_STARTING, * (request_rec *) NULL); * * This state should be listed separately in the scoreboard, in some kind * of process_status, not mixed in with the worker threads' status. * "life_status" is almost right, but it's in the worker's structure, and * the name could be clearer. gla */ apr_thread_exit(thd, APR_SUCCESS); return NULL; } static void join_workers(apr_thread_t *listener, apr_thread_t **threads) { int i; apr_status_t rv, thread_rv; if (listener) { int iter; /* deal with a rare timing window which affects waking up the * listener thread... if the signal sent to the listener thread * is delivered between the time it verifies that the * listener_may_exit flag is clear and the time it enters a * blocking syscall, the signal didn't do any good... work around * that by sleeping briefly and sending it again */ iter = 0; while (iter < 10 && #ifdef HAVE_PTHREAD_KILL pthread_kill(*listener_os_thread, 0) #else kill(ap_my_pid, 0) #endif == 0) { /* listener not dead yet */ apr_sleep(apr_time_make(0, 500000)); wakeup_listener(); ++iter; } if (iter >= 10) { ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, "the listener thread didn't exit"); } else { rv = apr_thread_join(&thread_rv, listener); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, "apr_thread_join: unable to join listener thread"); } } } for (i = 0; i < ap_threads_per_child; i++) { if (threads[i]) { /* if we ever created this thread */ #ifdef HAVE_PTHREAD_KILL apr_os_thread_t *worker_os_thread; apr_os_thread_get(&worker_os_thread, threads[i]); pthread_kill(*worker_os_thread, WORKER_SIGNAL); #endif rv = apr_thread_join(&thread_rv, threads[i]); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, "apr_thread_join: unable to join worker " "thread %d", i); } } } } static void join_start_thread(apr_thread_t *start_thread_id) { apr_status_t rv, thread_rv; start_thread_may_exit = 1; /* tell it to give up in case it is still * trying to take over slots from a * previous generation */ rv = apr_thread_join(&thread_rv, start_thread_id); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, "apr_thread_join: unable to join the start " "thread"); } } static void child_main(int child_num_arg) { apr_thread_t **threads; apr_status_t rv; thread_starter *ts; apr_threadattr_t *thread_attr; apr_thread_t *start_thread_id; mpm_state = AP_MPMQ_STARTING; /* for benefit of any hooks that run as this * child initializes */ ap_my_pid = getpid(); ap_fatal_signal_child_setup(ap_server_conf); apr_pool_create(&pchild, pconf); /*stuff to do before we switch id's, so we have permissions.*/ ap_reopen_scoreboard(pchild, NULL, 0); rv = SAFE_ACCEPT(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); /* done with init critical section */ /* Just use the standard apr_setup_signal_thread to block all signals * from being received. The child processes no longer use signals for * any communication with the parent process. */ rv = apr_setup_signal_thread(); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, "Couldn't initialize signal thread"); clean_child_exit(APEXIT_CHILDFATAL); } if (ap_max_requests_per_child) { requests_this_child = ap_max_requests_per_child; } else { /* coding a value of zero means infinity */ requests_this_child = INT_MAX; } /* Setup worker threads */ /* clear the storage; we may not create all our threads immediately, * and we want a 0 entry to indicate a thread which was not created */ threads = (apr_thread_t **)calloc(1, sizeof(apr_thread_t *) * ap_threads_per_child); if (threads == NULL) { ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf, "malloc: out of memory"); clean_child_exit(APEXIT_CHILDFATAL); } ts = (thread_starter *)apr_palloc(pchild, sizeof(*ts)); apr_threadattr_create(&thread_attr, pchild); /* 0 means PTHREAD_CREATE_JOINABLE */ apr_threadattr_detach_set(thread_attr, 0); if (ap_thread_stacksize != 0) { apr_threadattr_stacksize_set(thread_attr, ap_thread_stacksize); } ts->threads = threads; ts->listener = NULL; ts->child_num_arg = child_num_arg; ts->threadattr = thread_attr; rv = apr_thread_create(&start_thread_id, thread_attr, start_threads, ts, pchild); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, "apr_thread_create: unable to create worker thread"); /* let the parent decide how bad this really is */ clean_child_exit(APEXIT_CHILDSICK); } mpm_state = AP_MPMQ_RUNNING; /* If we are only running in one_process mode, we will want to * still handle signals. */ if (one_process) { /* Block until we get a terminating signal. */ apr_signal_thread(check_signal); /* make sure the start thread has finished; signal_threads() * and join_workers() depend on that */ /* XXX join_start_thread() won't be awakened if one of our * threads encounters a critical error and attempts to * shutdown this child */ join_start_thread(start_thread_id); signal_threads(ST_UNGRACEFUL); /* helps us terminate a little more * quickly than the dispatch of the signal thread * beats the Pipe of Death and the browsers */ /* A terminating signal was received. Now join each of the * workers to clean them up. * If the worker already exited, then the join frees * their resources and returns. * If the worker hasn't exited, then this blocks until * they have (then cleans up). */ join_workers(ts->listener, threads); } else { /* !one_process */ /* remove SIGTERM from the set of blocked signals... if one of * the other threads in the process needs to take us down * (e.g., for MaxRequestsPerChild) it will send us SIGTERM */ unblock_signal(SIGTERM); apr_signal(SIGTERM, dummy_signal_handler); /* Watch for any messages from the parent over the POD */ while (1) { rv = ap_mpm_pod_check(pod); if (rv == AP_NORESTART) { /* see if termination was triggered while we slept */ switch(terminate_mode) { case ST_GRACEFUL: rv = AP_GRACEFUL; break; case ST_UNGRACEFUL: rv = AP_RESTART; break; } } if (rv == AP_GRACEFUL || rv == AP_RESTART) { /* make sure the start thread has finished; * signal_threads() and join_workers depend on that */ join_start_thread(start_thread_id); signal_threads(rv == AP_GRACEFUL ? ST_GRACEFUL : ST_UNGRACEFUL); break; } } /* A terminating signal was received. Now join each of the * workers to clean them up. * If the worker already exited, then the join frees * their resources and returns. * If the worker hasn't exited, then this blocks until * they have (then cleans up). */ join_workers(ts->listener, threads); } free(threads); clean_child_exit(resource_shortage ? APEXIT_CHILDSICK : 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) { set_signals(); ap_scoreboard_image->parent[slot].pid = getpid(); child_main(slot); } if ((pid = fork()) == -1) { 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 */ ap_update_child_status_from_indexes(slot, 0, SERVER_DEAD, 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. */ apr_sleep(apr_time_from_sec(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); apr_signal(SIGTERM, just_die); child_main(slot); clean_child_exit(0); } /* else */ if (ap_scoreboard_image->parent[slot].pid != 0) { /* This new child process is squatting on the scoreboard * entry owned by an exiting child process, which cannot * exit until all active requests complete. * Don't forget about this exiting child process, or we * won't be able to kill it if it doesn't exit by the * time the server is shut down. */ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, "taking over scoreboard slot from %" APR_PID_T_FMT "%s", ap_scoreboard_image->parent[slot].pid, ap_scoreboard_image->parent[slot].quiescing ? " (quiescing)" : ""); ap_register_extra_mpm_process(ap_scoreboard_image->parent[slot].pid); } ap_scoreboard_image->parent[slot].quiescing = 0; 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->parent[i].pid != 0) { 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(void) { int i, j; int idle_thread_count; worker_score *ws; process_score *ps; int free_length; int totally_free_length = 0; int free_slots[MAX_SPAWN_RATE]; int last_non_dead; int total_non_dead; int active_thread_count = 0; /* initialize the free_list */ free_length = 0; idle_thread_count = 0; last_non_dead = -1; total_non_dead = 0; for (i = 0; i < ap_daemons_limit; ++i) { /* Initialization to satisfy the compiler. It doesn't know * that ap_threads_per_child is always > 0 */ int status = SERVER_DEAD; int any_dying_threads = 0; int any_dead_threads = 0; int all_dead_threads = 1; if (i >= ap_max_daemons_limit && totally_free_length == idle_spawn_rate) break; ps = &ap_scoreboard_image->parent[i]; for (j = 0; j < ap_threads_per_child; j++) { ws = &ap_scoreboard_image->servers[i][j]; status = ws->status; /* XXX any_dying_threads is probably no longer needed GLA */ any_dying_threads = any_dying_threads || (status == SERVER_GRACEFUL); any_dead_threads = any_dead_threads || (status == SERVER_DEAD); all_dead_threads = all_dead_threads && (status == SERVER_DEAD || status == SERVER_GRACEFUL); /* 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 (ps->pid != 0) { /* XXX just set all_dead_threads in outer for loop if no pid? not much else matters */ if (status <= SERVER_READY && !ps->quiescing && ps->generation == ap_my_generation) { ++idle_thread_count; } if (status >= SERVER_READY && status < SERVER_GRACEFUL) { ++active_thread_count; } } } if (any_dead_threads && totally_free_length < idle_spawn_rate && free_length < MAX_SPAWN_RATE && (!ps->pid /* no process in the slot */ || ps->quiescing)) { /* or at least one is going away */ if (all_dead_threads) { /* great! we prefer these, because the new process can * start more threads sooner. So prioritize this slot * by putting it ahead of any slots with active threads. * * first, make room by moving a slot that's potentially still * in use to the end of the array */ free_slots[free_length] = free_slots[totally_free_length]; free_slots[totally_free_length++] = i; } else { /* slot is still in use - back of the bus */ free_slots[free_length] = i; } ++free_length; } /* XXX if (!ps->quiescing) is probably more reliable GLA */ if (!any_dying_threads) { last_non_dead = i; ++total_non_dead; } } if (sick_child_detected) { if (active_thread_count > 0) { /* some child processes appear to be working. don't kill the * whole server. */ sick_child_detected = 0; } else { /* looks like a basket case. give up. */ shutdown_pending = 1; child_fatal = 1; ap_log_error(APLOG_MARK, APLOG_ALERT, 0, ap_server_conf, "No active workers found..." " Apache is exiting!"); /* the child already logged the failure details */ return; } } ap_max_daemons_limit = last_non_dead + 1; if (idle_thread_count > max_spare_threads) { /* Kill off one child */ ap_mpm_pod_signal(pod, TRUE); idle_spawn_rate = 1; } else if (idle_thread_count < min_spare_threads) { /* 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 (free_length > idle_spawn_rate) { free_length = idle_spawn_rate; } 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, ThreadsPerChild " "or Min/MaxSpareThreads), " "spawning %d children, there are around %d idle " "threads, and %d total children", free_length, idle_thread_count, total_non_dead); } for (i = 0; i < free_length; ++i) { make_child(ap_server_conf, free_slots[i]); } /* 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; } } static void server_main_loop(int remaining_children_to_start) { int child_slot; apr_exit_why_e exitwhy; int status, processed_status; apr_proc_t pid; int i; while (!restart_pending && !shutdown_pending) { ap_wait_or_timeout(&exitwhy, &status, &pid, pconf); if (pid.pid != -1) { processed_status = ap_process_child_status(&pid, exitwhy, status); if (processed_status == APEXIT_CHILDFATAL) { shutdown_pending = 1; child_fatal = 1; return; } else if (processed_status == APEXIT_CHILDSICK) { /* tell perform_idle_server_maintenance to check into this * on the next timer pop */ sick_child_detected = 1; } /* non-fatal death... note that it's gone in the scoreboard. */ child_slot = find_child_by_pid(&pid); if (child_slot >= 0) { for (i = 0; i < ap_threads_per_child; i++) ap_update_child_status_from_indexes(child_slot, i, SERVER_DEAD, (request_rec *) NULL); ap_scoreboard_image->parent[child_slot].pid = 0; ap_scoreboard_image->parent[child_slot].quiescing = 0; if (processed_status == APEXIT_CHILDSICK) { /* resource shortage, minimize the fork rate */ 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; } } else if (ap_unregister_extra_mpm_process(pid.pid) == 1) { /* handled */ #if APR_HAS_OTHER_CHILD } else if (apr_proc_other_child_alert(&pid, APR_OC_REASON_DEATH, 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(); } } int ap_mpm_run(apr_pool_t *_pconf, apr_pool_t *plog, server_rec *s) { int remaining_children_to_start; apr_status_t rv; ap_log_pid(pconf, ap_pid_fname); first_server_limit = server_limit; first_thread_limit = thread_limit; if (changed_limit_at_restart) { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, "WARNING: Attempt to change ServerLimit or ThreadLimit " "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(); /* Don't thrash... */ if (max_spare_threads < min_spare_threads + ap_threads_per_child) max_spare_threads = min_spare_threads + ap_threads_per_child; /* 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_description()); 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; server_main_loop(remaining_children_to_start); mpm_state = AP_MPMQ_STOPPING; if (shutdown_pending && !is_graceful) { /* Time to shut down: * Kill child processes, tell them to call child_exit, etc... */ ap_mpm_pod_killpg(pod, ap_daemons_limit, FALSE); ap_reclaim_child_processes(1); /* Start with SIGTERM */ if (!child_fatal) { /* 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=%" APR_PID_T_FMT ")", pidfile, getpid()); ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, "caught SIGTERM, shutting down"); } return 1; } else if (shutdown_pending) { /* Time to gracefully shut down: * Kill child processes, tell them to call child_exit, etc... */ int active_children; int index; apr_time_t cutoff = 0; /* Close our listeners, and then ask our children to do same */ ap_close_listeners(); ap_mpm_pod_killpg(pod, ap_daemons_limit, TRUE); ap_relieve_child_processes(); if (!child_fatal) { /* 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=%" APR_PID_T_FMT ")", pidfile, getpid()); ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, "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 */ shutdown_pending = 0; do { /* Pause for a second */ apr_sleep(apr_time_from_sec(1)); /* Relieve any children which have now exited */ ap_relieve_child_processes(); 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 (!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_mpm_pod_killpg(pod, ap_daemons_limit, FALSE); ap_reclaim_child_processes(1); 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, AP_SIG_GRACEFUL_STRING " received. Doing graceful restart"); /* wake up the children...time to die. But we'll have more soon */ ap_mpm_pod_killpg(pod, ap_daemons_limit, TRUE); /* This is mostly for debugging... so that we know what is still * gracefully dealing with existing request. */ } else { /* Kill 'em all. Since the child acts the same on the parents SIGTERM * and a SIGHUP, we may as well use the same signal, because some user * pthreads are stealing signals from us left and right. */ ap_mpm_pod_killpg(pod, ap_daemons_limit, FALSE); ap_reclaim_child_processes(1); /* Start with SIGTERM */ 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 worker_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 (!one_process) { 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 worker_pre_config(apr_pool_t *pconf, apr_pool_t *plog, apr_pool_t *ptemp) { static int restart_num = 0; int no_detach, debug, foreground; ap_directive_t *pdir; ap_directive_t *max_clients = NULL; apr_status_t rv; mpm_state = AP_MPMQ_STARTING; /* make sure that "ThreadsPerChild" gets set before "MaxClients" */ for (pdir = ap_conftree; pdir != NULL; pdir = pdir->next) { if (strncasecmp(pdir->directive, "ThreadsPerChild", 15) == 0) { if (!max_clients) { break; /* we're in the clear, got ThreadsPerChild first */ } else { /* now to swap the data */ ap_directive_t temp; temp.directive = pdir->directive; temp.args = pdir->args; /* Make sure you don't change 'next', or you may get loops! */ /* XXX: first_child, parent, and data can never be set * for these directives, right? -aaron */ temp.filename = pdir->filename; temp.line_num = pdir->line_num; pdir->directive = max_clients->directive; pdir->args = max_clients->args; pdir->filename = max_clients->filename; pdir->line_num = max_clients->line_num; max_clients->directive = temp.directive; max_clients->args = temp.args; max_clients->filename = temp.filename; max_clients->line_num = temp.line_num; break; } } else if (!max_clients && strncasecmp(pdir->directive, "MaxClients", 10) == 0) { max_clients = pdir; } } debug = ap_exists_config_define("DEBUG"); if (debug) { foreground = one_process = 1; no_detach = 0; } else { one_process = ap_exists_config_define("ONE_PROCESS"); no_detach = ap_exists_config_define("NO_DETACH"); 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; min_spare_threads = DEFAULT_MIN_FREE_DAEMON * DEFAULT_THREADS_PER_CHILD; max_spare_threads = DEFAULT_MAX_FREE_DAEMON * DEFAULT_THREADS_PER_CHILD; ap_daemons_limit = server_limit; ap_threads_per_child = DEFAULT_THREADS_PER_CHILD; 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 worker_hooks(apr_pool_t *p) { /* The worker 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}; one_process = 0; ap_hook_open_logs(worker_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(worker_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_spare_threads(cmd_parms *cmd, void *dummy, const char *arg) { const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } min_spare_threads = atoi(arg); if (min_spare_threads <= 0) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: detected MinSpareThreads 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."); min_spare_threads = 1; } return NULL; } static const char *set_max_spare_threads(cmd_parms *cmd, void *dummy, const char *arg) { const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } max_spare_threads = atoi(arg); return NULL; } static const char *set_max_clients (cmd_parms *cmd, void *dummy, const char *arg) { int max_clients; const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } /* It is ok to use ap_threads_per_child here because we are * sure that it gets set before MaxClients in the pre_config stage. */ max_clients = atoi(arg); if (max_clients < ap_threads_per_child) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: MaxClients (%d) must be at least as large", max_clients); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, " as ThreadsPerChild (%d). Automatically", ap_threads_per_child); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, " increasing MaxClients to %d.", ap_threads_per_child); max_clients = ap_threads_per_child; } ap_daemons_limit = max_clients / ap_threads_per_child; if ((max_clients > 0) && (max_clients % ap_threads_per_child)) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: MaxClients (%d) is not an integer multiple", max_clients); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, " of ThreadsPerChild (%d), lowering MaxClients to %d", ap_threads_per_child, ap_daemons_limit * ap_threads_per_child); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, " for a maximum of %d child processes,", ap_daemons_limit); max_clients = ap_daemons_limit * ap_threads_per_child; } if (ap_daemons_limit > server_limit) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: MaxClients of %d would require %d servers,", max_clients, ap_daemons_limit); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, " and would exceed the ServerLimit value of %d.", server_limit); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, " Automatically lowering MaxClients to %d. To increase,", server_limit * ap_threads_per_child); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, " please see the ServerLimit 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_threads_per_child (cmd_parms *cmd, void *dummy, const char *arg) { const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } ap_threads_per_child = atoi(arg); if (ap_threads_per_child > thread_limit) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: ThreadsPerChild of %d exceeds ThreadLimit " "value of %d", ap_threads_per_child, thread_limit); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "threads, lowering ThreadsPerChild to %d. To increase, please" " see the", thread_limit); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, " ThreadLimit directive."); ap_threads_per_child = thread_limit; } else if (ap_threads_per_child < 1) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: Require ThreadsPerChild > 0, setting to 1"); ap_threads_per_child = 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 char *set_thread_limit (cmd_parms *cmd, void *dummy, const char *arg) { int tmp_thread_limit; const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } tmp_thread_limit = atoi(arg); /* you cannot change ThreadLimit across a restart; ignore * any such attempts */ if (first_thread_limit && tmp_thread_limit != thread_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; } thread_limit = tmp_thread_limit; if (thread_limit > MAX_THREAD_LIMIT) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: ThreadLimit of %d exceeds compile time limit " "of %d servers,", thread_limit, MAX_THREAD_LIMIT); ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, " lowering ThreadLimit to %d.", MAX_THREAD_LIMIT); thread_limit = MAX_THREAD_LIMIT; } else if (thread_limit < 1) { ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "WARNING: Require ThreadLimit > 0, setting to 1"); thread_limit = 1; } return NULL; } static const command_rec worker_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("MinSpareThreads", set_min_spare_threads, NULL, RSRC_CONF, "Minimum number of idle threads, to handle request spikes"), AP_INIT_TAKE1("MaxSpareThreads", set_max_spare_threads, NULL, RSRC_CONF, "Maximum number of idle threads"), AP_INIT_TAKE1("MaxClients", set_max_clients, NULL, RSRC_CONF, "Maximum number of threads alive at the same time"), AP_INIT_TAKE1("ThreadsPerChild", set_threads_per_child, NULL, RSRC_CONF, "Number of threads each child creates"), AP_INIT_TAKE1("ServerLimit", set_server_limit, NULL, RSRC_CONF, "Maximum number of child processes for this run of Apache"), AP_INIT_TAKE1("ThreadLimit", set_thread_limit, NULL, RSRC_CONF, "Maximum number of worker threads per child process for this run of Apache - Upper limit for ThreadsPerChild"), AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND, { NULL } }; module AP_MODULE_DECLARE_DATA mpm_worker_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 */ worker_cmds, /* command apr_table_t */ worker_hooks /* register_hooks */ };
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