/* 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. */ /** * This MPM tries to fix the 'keep alive problem' in HTTP. * * After a client completes the first request, the client can keep the * connection open to send more requests with the same socket. This can save * significant overhead in creating TCP connections. However, the major * disadvantage is that Apache traditionally keeps an entire child * process/thread waiting for data from the client. To solve this problem, * this MPM has a dedicated thread for handling both the Listening sockets, * and all sockets that are in a Keep Alive status. * * The MPM assumes the underlying apr_pollset implementation is somewhat * threadsafe. This currently is only compatible with KQueue and EPoll. This * enables the MPM to avoid extra high level locking or having to wake up the * listener thread when a keep-alive socket needs to be sent to it. * * This MPM does not perform well on older platforms that do not have very good * threading, like Linux with a 2.4 kernel, but this does not matter, since we * require EPoll or KQueue. * * For FreeBSD, use 5.3. It is possible to run this MPM on FreeBSD 5.2.1, if * you use libkse (see `man libmap.conf`). * * For NetBSD, use at least 2.0. * * For Linux, you should use a 2.6 kernel, and make sure your glibc has epoll * support compiled in. * */ #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_poll.h" #include "apr_ring.h" #include "apr_queue.h" #include "apr_atomic.h" #define APR_WANT_STRFUNC #include "apr_want.h" #include "apr_version.h" #include #if APR_HAVE_UNISTD_H #include #endif #if APR_HAVE_SYS_SOCKET_H #include #endif #if APR_HAVE_SYS_WAIT_H #include #endif #ifdef HAVE_SYS_PROCESSOR_H #include /* for bindprocessor() */ #endif #if !APR_HAS_THREADS #error The Event MPM requires APR threads, but they are unavailable. #endif #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 "http_protocol.h" #include "ap_mpm.h" #include "mpm_common.h" #include "ap_listen.h" #include "scoreboard.h" #include "mpm_fdqueue.h" #include "mpm_default.h" #include "http_vhost.h" #include "unixd.h" #include "apr_skiplist.h" #include "util_time.h" #include #include /* for INT_MAX */ #if HAVE_SERF #include "mod_serf.h" #include "serf.h" #endif /* 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 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 100000 #endif #define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid) #if !APR_VERSION_AT_LEAST(1,4,0) #define apr_time_from_msec(x) (x * 1000) #endif #define CONN_STATE_IS_LINGERING_CLOSE(s) ((s) >= CONN_STATE_LINGER && \ (s) <= CONN_STATE_LINGER_SHORT) #ifndef MAX_SECS_TO_LINGER #define MAX_SECS_TO_LINGER 30 #endif #define SECONDS_TO_LINGER 2 /* * Actual definitions of config globals */ #ifndef DEFAULT_WORKER_FACTOR #define DEFAULT_WORKER_FACTOR 2 #endif #define WORKER_FACTOR_SCALE 16 /* scale factor to allow fractional values */ static unsigned int worker_factor = DEFAULT_WORKER_FACTOR * WORKER_FACTOR_SCALE; /* AsyncRequestWorkerFactor * 16 */ static int threads_per_child = 0; /* ThreadsPerChild */ static int ap_daemons_to_start = 0; /* StartServers */ static int min_spare_threads = 0; /* MinSpareThreads */ static int max_spare_threads = 0; /* MaxSpareThreads */ static int active_daemons_limit = 0; /* MaxRequestWorkers / ThreadsPerChild */ static int max_workers = 0; /* MaxRequestWorkers */ static int server_limit = 0; /* ServerLimit */ static int thread_limit = 0; /* ThreadLimit */ static int had_healthy_child = 0; static volatile int dying = 0; static volatile int workers_may_exit = 0; static volatile int start_thread_may_exit = 0; static volatile int listener_may_exit = 0; static int listener_is_wakeable = 0; /* Pollset supports APR_POLLSET_WAKEABLE */ static int num_listensocks = 0; static apr_int32_t conns_this_child; /* MaxConnectionsPerChild, only access in listener thread */ static apr_uint32_t connection_count = 0; /* Number of open connections */ static apr_uint32_t lingering_count = 0; /* Number of connections in lingering close */ static apr_uint32_t suspended_count = 0; /* Number of suspended connections */ static apr_uint32_t clogged_count = 0; /* Number of threads processing ssl conns */ static apr_uint32_t threads_shutdown = 0; /* Number of threads that have shutdown early during graceful termination */ static int resource_shortage = 0; static fd_queue_t *worker_queue; static fd_queue_info_t *worker_queue_info; static apr_thread_mutex_t *timeout_mutex; module AP_MODULE_DECLARE_DATA mpm_event_module; /* forward declare */ struct event_srv_cfg_s; typedef struct event_srv_cfg_s event_srv_cfg; static apr_pollfd_t *listener_pollfd; /* * The pollset for sockets that are in any of the timeout queues. Currently * we use the timeout_mutex to make sure that connections are added/removed * atomically to/from both event_pollset and a timeout queue. Otherwise * some confusion can happen under high load if timeout queues and pollset * get out of sync. * XXX: It should be possible to make the lock unnecessary in many or even all * XXX: cases. */ static apr_pollset_t *event_pollset; typedef struct event_conn_state_t event_conn_state_t; /* * The chain of connections to be shutdown by a worker thread (deferred), * linked list updated atomically. */ static event_conn_state_t *volatile defer_linger_chain; struct event_conn_state_t { /** APR_RING of expiration timeouts */ APR_RING_ENTRY(event_conn_state_t) timeout_list; /** the time when the entry was queued */ apr_time_t queue_timestamp; /** connection record this struct refers to */ conn_rec *c; /** request record (if any) this struct refers to */ request_rec *r; /** server config this struct refers to */ event_srv_cfg *sc; /** scoreboard handle for the conn_rec */ ap_sb_handle_t *sbh; /** is the current conn_rec suspended? (disassociated with * a particular MPM thread; for suspend_/resume_connection * hooks) */ int suspended; /** memory pool to allocate from */ apr_pool_t *p; /** bucket allocator */ apr_bucket_alloc_t *bucket_alloc; /** poll file descriptor information */ apr_pollfd_t pfd; /** public parts of the connection state */ conn_state_t pub; /** chaining in defer_linger_chain */ struct event_conn_state_t *chain; unsigned int /** Is lingering close from defer_lingering_close()? */ deferred_linger :1, /** Has ap_start_lingering_close() been called? */ linger_started :1; }; APR_RING_HEAD(timeout_head_t, event_conn_state_t); struct timeout_queue { struct timeout_head_t head; apr_interval_time_t timeout; apr_uint32_t count; /* for this queue */ apr_uint32_t *total; /* for all chained/related queues */ struct timeout_queue *next; /* chaining */ }; /* * Several timeout queues that use different timeouts, so that we always can * simply append to the end. * waitio_q uses vhost's TimeOut * write_completion_q uses vhost's TimeOut * keepalive_q uses vhost's KeepAliveTimeOut * linger_q uses MAX_SECS_TO_LINGER * short_linger_q uses SECONDS_TO_LINGER */ static struct timeout_queue *waitio_q, *write_completion_q, *keepalive_q, *linger_q, *short_linger_q; static volatile apr_time_t queues_next_expiry; /* Prevent extra poll/wakeup calls for timeouts close in the future (queues * have the granularity of a second anyway). * XXX: Wouldn't 0.5s (instead of 0.1s) be "enough"? */ #define TIMEOUT_FUDGE_FACTOR apr_time_from_msec(100) /* * Macros for accessing struct timeout_queue. * For TO_QUEUE_APPEND and TO_QUEUE_REMOVE, timeout_mutex must be held. */ static void TO_QUEUE_APPEND(struct timeout_queue *q, event_conn_state_t *el) { apr_time_t elem_expiry; apr_time_t next_expiry; APR_RING_INSERT_TAIL(&q->head, el, event_conn_state_t, timeout_list); ++*q->total; ++q->count; /* Cheaply update the global queues_next_expiry with the one of the * first entry of this queue (oldest) if it expires before. */ el = APR_RING_FIRST(&q->head); elem_expiry = el->queue_timestamp + q->timeout; next_expiry = queues_next_expiry; if (!next_expiry || next_expiry > elem_expiry + TIMEOUT_FUDGE_FACTOR) { queues_next_expiry = elem_expiry; /* Unblock the poll()ing listener for it to update its timeout. */ if (listener_is_wakeable) { apr_pollset_wakeup(event_pollset); } } } static void TO_QUEUE_REMOVE(struct timeout_queue *q, event_conn_state_t *el) { APR_RING_REMOVE(el, timeout_list); APR_RING_ELEM_INIT(el, timeout_list); --*q->total; --q->count; } static struct timeout_queue *TO_QUEUE_MAKE(apr_pool_t *p, apr_time_t t, struct timeout_queue *ref) { struct timeout_queue *q; q = apr_pcalloc(p, sizeof *q); APR_RING_INIT(&q->head, event_conn_state_t, timeout_list); q->total = (ref) ? ref->total : apr_pcalloc(p, sizeof *q->total); q->timeout = t; return q; } #define TO_QUEUE_ELEM_INIT(el) \ APR_RING_ELEM_INIT((el), timeout_list) #if HAVE_SERF typedef struct { apr_pollset_t *pollset; apr_pool_t *pool; } s_baton_t; static serf_context_t *g_serf; #endif /* The structure used to pass unique initialization info to each thread */ typedef struct { int pslot; /* process slot */ int tslot; /* worker slot of the thread */ } 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; typedef enum { PT_CSD, PT_ACCEPT #if HAVE_SERF , PT_SERF #endif , PT_USER } poll_type_e; typedef struct { poll_type_e type; void *baton; } listener_poll_type; typedef struct socket_callback_baton { ap_mpm_callback_fn_t *cbfunc; void *user_baton; apr_array_header_t *pfds; timer_event_t *cancel_event; /* If a timeout was requested, a pointer to the timer event */ struct socket_callback_baton *next; unsigned int signaled :1; } socket_callback_baton_t; typedef struct event_child_bucket { ap_pod_t *pod; ap_listen_rec *listeners; } event_child_bucket; static event_child_bucket *my_bucket; /* Current child bucket */ /* data retained by event across load/unload of the module * allocated on first call to pre-config hook; located on * subsequent calls to pre-config hook */ typedef struct event_retained_data { ap_unixd_mpm_retained_data *mpm; apr_pool_t *gen_pool; /* generation pool (children start->stop lifetime) */ event_child_bucket *buckets; /* children buckets (reset per generation) */ int first_server_limit; int first_thread_limit; int sick_child_detected; int maxclients_reported; int near_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_daemon_used; /* * All running workers, active and shutting down, including those that * may be left from before a graceful restart. * Not kept up-to-date when shutdown is pending. */ int total_daemons; /* * Workers that still active, i.e. are not shutting down gracefully. */ int active_daemons; /* * 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 * maintained per listeners bucket, doubled up to MAX_SPAWN_RATE, and * reset only when a cycle goes by without the need to spawn. */ int *idle_spawn_rate; int hold_off_on_exponential_spawning; } event_retained_data; static event_retained_data *retained; #ifndef MAX_SPAWN_RATE #define MAX_SPAWN_RATE 32 #endif static int max_spawn_rate_per_bucket = MAX_SPAWN_RATE / 1; struct event_srv_cfg_s { struct timeout_queue *io_q, *wc_q, *ka_q; }; #define ID_FROM_CHILD_THREAD(c, t) ((c * thread_limit) + t) /* The event 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 apr_pool_t *pruntime; /* Pool for MPM threads 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; static int ap_child_slot; /* Current child process slot in scoreboard */ /* 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 /* 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 volatile apr_uint32_t listensocks_disabled; static void disable_listensocks(void) { int i; if (apr_atomic_cas32(&listensocks_disabled, 1, 0) != 0) { return; } if (event_pollset) { for (i = 0; i < num_listensocks; i++) { apr_pollset_remove(event_pollset, &listener_pollfd[i]); } } ap_scoreboard_image->parent[ap_child_slot].not_accepting = 1; } static void enable_listensocks(void) { int i; if (listener_may_exit || apr_atomic_cas32(&listensocks_disabled, 0, 1) != 1) { return; } ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00457) "Accepting new connections again: " "%u active conns (%u lingering/%u clogged/%u suspended), " "%u idle workers", apr_atomic_read32(&connection_count), apr_atomic_read32(&lingering_count), apr_atomic_read32(&clogged_count), apr_atomic_read32(&suspended_count), ap_queue_info_num_idlers(worker_queue_info)); for (i = 0; i < num_listensocks; i++) apr_pollset_add(event_pollset, &listener_pollfd[i]); /* * XXX: This is not yet optimal. If many workers suddenly become available, * XXX: the parent may kill some processes off too soon. */ ap_scoreboard_image->parent[ap_child_slot].not_accepting = 0; } static APR_INLINE apr_uint32_t listeners_disabled(void) { return apr_atomic_read32(&listensocks_disabled); } static APR_INLINE int connections_above_limit(int *busy) { apr_uint32_t i_count = ap_queue_info_num_idlers(worker_queue_info); if (i_count > 0) { apr_uint32_t c_count = apr_atomic_read32(&connection_count); apr_uint32_t l_count = apr_atomic_read32(&lingering_count); if (c_count <= l_count /* Off by 'listeners_disabled()' to avoid flip flop */ || c_count - l_count < (apr_uint32_t)threads_per_child + (i_count - listeners_disabled()) * (worker_factor / WORKER_FACTOR_SCALE)) { return 0; } } else if (busy) { *busy = 1; } return 1; } static APR_INLINE int should_enable_listensocks(void) { return !dying && listeners_disabled() && !connections_above_limit(NULL); } static void close_socket_nonblocking_(apr_socket_t *csd, const char *from, int line) { apr_status_t rv; apr_os_sock_t fd = -1; /* close_worker_sockets() may have closed it already */ rv = apr_os_sock_get(&fd, csd); ap_log_error(APLOG_MARK, APLOG_TRACE8, 0, ap_server_conf, "closing socket %i/%pp from %s:%i", (int)fd, csd, from, line); if (rv == APR_SUCCESS && fd == -1) { return; } apr_socket_timeout_set(csd, 0); rv = apr_socket_close(csd); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(00468) "error closing socket"); AP_DEBUG_ASSERT(0); } } #define close_socket_nonblocking(csd) \ close_socket_nonblocking_(csd, __FUNCTION__, __LINE__) static void close_worker_sockets(void) { int i; for (i = 0; i < threads_per_child; i++) { apr_socket_t *csd = worker_sockets[i]; if (csd) { worker_sockets[i] = NULL; close_socket_nonblocking(csd); } } } static void wakeup_listener(void) { ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, "wake up listener%s", listener_may_exit ? " again" : ""); listener_may_exit = 1; disable_listensocks(); /* Unblock the listener if it's poll()ing */ if (event_pollset && listener_is_wakeable) { apr_pollset_wakeup(event_pollset); } /* unblock the listener if it's waiting for a worker */ if (worker_queue_info) { ap_queue_info_term(worker_queue_info); } 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; retained->mpm->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); close_worker_sockets(); /* forcefully kill all current connections */ } ap_run_child_stopping(pchild, mode == ST_GRACEFUL); } static int event_query(int query_code, int *result, apr_status_t *rv) { *rv = APR_SUCCESS; switch (query_code) { case AP_MPMQ_MAX_DAEMON_USED: *result = retained->max_daemon_used; break; case AP_MPMQ_IS_THREADED: *result = AP_MPMQ_STATIC; break; case AP_MPMQ_IS_FORKED: *result = AP_MPMQ_DYNAMIC; break; case AP_MPMQ_IS_ASYNC: *result = 1; break; case AP_MPMQ_HAS_SERF: *result = 1; break; case AP_MPMQ_HARD_LIMIT_DAEMONS: *result = server_limit; break; case AP_MPMQ_HARD_LIMIT_THREADS: *result = thread_limit; break; case AP_MPMQ_MAX_THREADS: *result = threads_per_child; break; case AP_MPMQ_MIN_SPARE_DAEMONS: *result = 0; break; case AP_MPMQ_MIN_SPARE_THREADS: *result = min_spare_threads; break; case AP_MPMQ_MAX_SPARE_DAEMONS: *result = 0; break; case AP_MPMQ_MAX_SPARE_THREADS: *result = max_spare_threads; break; case AP_MPMQ_MAX_REQUESTS_DAEMON: *result = ap_max_requests_per_child; break; case AP_MPMQ_MAX_DAEMONS: *result = active_daemons_limit; break; case AP_MPMQ_MPM_STATE: *result = retained->mpm->mpm_state; break; case AP_MPMQ_GENERATION: *result = retained->mpm->my_generation; break; case AP_MPMQ_CAN_SUSPEND: *result = 1; break; case AP_MPMQ_CAN_POLL: *result = 1; break; case AP_MPMQ_CAN_WAITIO: *result = 1; break; default: *rv = APR_ENOTIMPL; break; } return OK; } static void event_note_child_stopped(int slot, pid_t pid, ap_generation_t gen) { if (slot != -1) { /* child had a scoreboard slot? */ process_score *ps = &ap_scoreboard_image->parent[slot]; int i; pid = ps->pid; gen = ps->generation; for (i = 0; i < threads_per_child; i++) { ap_update_child_status_from_indexes(slot, i, SERVER_DEAD, NULL); } ap_run_child_status(ap_server_conf, pid, gen, slot, MPM_CHILD_EXITED); if (ps->quiescing != 2) { /* vs perform_idle_server_maintenance() */ retained->active_daemons--; } retained->total_daemons--; ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, "Child %d stopped: pid %d, gen %d, " "active %d/%d, total %d/%d/%d, quiescing %d", slot, (int)pid, (int)gen, retained->active_daemons, active_daemons_limit, retained->total_daemons, retained->max_daemon_used, server_limit, ps->quiescing); ps->not_accepting = 0; ps->quiescing = 0; ps->pid = 0; } else { ap_run_child_status(ap_server_conf, pid, gen, -1, MPM_CHILD_EXITED); } } static void event_note_child_started(int slot, pid_t pid) { ap_generation_t gen = retained->mpm->my_generation; retained->total_daemons++; retained->active_daemons++; 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); ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, "Child %d started: pid %d, gen %d, " "active %d/%d, total %d/%d/%d", slot, (int)pid, (int)gen, retained->active_daemons, active_daemons_limit, retained->total_daemons, retained->max_daemon_used, server_limit); } static const char *event_get_name(void) { return "event"; } /* 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; if (terminate_mode == ST_INIT) { ap_run_child_stopping(pchild, 0); } if (pchild) { ap_run_child_stopped(pchild, terminate_mode == ST_GRACEFUL); apr_pool_destroy(pchild); } if (one_process) { event_note_child_stopped(/* slot */ 0, 0, 0); } exit(code); } static void just_die(int sig) { clean_child_exit(0); } /***************************************************************** * Connection structures and accounting... */ static int child_fatal; static apr_status_t decrement_connection_count(void *cs_) { int is_last_connection; event_conn_state_t *cs = cs_; ap_log_cerror(APLOG_MARK, APLOG_TRACE8, 0, cs->c, "cleanup connection from state %i", (int)cs->pub.state); switch (cs->pub.state) { case CONN_STATE_LINGER: case CONN_STATE_LINGER_NORMAL: case CONN_STATE_LINGER_SHORT: apr_atomic_dec32(&lingering_count); break; case CONN_STATE_SUSPENDED: apr_atomic_dec32(&suspended_count); break; default: break; } /* Unblock the listener if it's waiting for connection_count = 0, * or if the listening sockets were disabled due to limits and can * now accept new connections. */ is_last_connection = !apr_atomic_dec32(&connection_count); if (listener_is_wakeable && ((is_last_connection && listener_may_exit) || should_enable_listensocks())) { apr_pollset_wakeup(event_pollset); } if (dying) { /* Help worker_thread_should_exit_early() */ ap_queue_interrupt_one(worker_queue); } return APR_SUCCESS; } static void notify_suspend(event_conn_state_t *cs) { ap_run_suspend_connection(cs->c, cs->r); cs->c->sbh = NULL; cs->suspended = 1; } static void notify_resume(event_conn_state_t *cs, int cleanup) { cs->suspended = 0; cs->c->sbh = cleanup ? NULL : cs->sbh; ap_run_resume_connection(cs->c, cs->r); } /* * Defer flush and close of the connection by adding it to defer_linger_chain, * for a worker to grab it and do the job (should that be blocking). * Pre-condition: nonblocking, can be called from anywhere provided cs is not * in any timeout queue or in the pollset. */ static int defer_lingering_close(event_conn_state_t *cs) { ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, cs->c, "deferring close from state %i", (int)cs->pub.state); /* The connection is not shutdown() yet strictly speaking, but it's not * in any queue nor handled by a worker either (will be very soon), so * to account for it somewhere we bump lingering_count now (and set * deferred_linger for process_lingering_close() to know). */ cs->pub.state = CONN_STATE_LINGER; apr_atomic_inc32(&lingering_count); cs->deferred_linger = 1; for (;;) { event_conn_state_t *chain = cs->chain = defer_linger_chain; if (apr_atomic_casptr((void *)&defer_linger_chain, cs, chain) != chain) { /* Race lost, try again */ continue; } return 1; } } /* Close the connection and release its resources (ptrans), either because an * unrecoverable error occured (queues or pollset add/remove) or more usually * if lingering close timed out. * Pre-condition: nonblocking, can be called from anywhere provided cs is not * in any timeout queue or in the pollset. */ static void close_connection(event_conn_state_t *cs) { ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, cs->c, "closing connection from state %i", (int)cs->pub.state); close_socket_nonblocking(cs->pfd.desc.s); ap_queue_info_push_pool(worker_queue_info, cs->p); } /* Shutdown the connection in case of timeout, error or resources shortage. * This starts short lingering close if not already there, or directly closes * the connection otherwise. * Pre-condition: nonblocking, can be called from anywhere provided cs is not * in any timeout queue or in the pollset. */ static int shutdown_connection(event_conn_state_t *cs) { if (!CONN_STATE_IS_LINGERING_CLOSE(cs->pub.state)) { apr_table_setn(cs->c->notes, "short-lingering-close", "1"); defer_lingering_close(cs); } else { close_connection(cs); } return 1; } /* * This runs before any non-MPM cleanup code on the connection; * if the connection is currently suspended as far as modules * know, provide notification of resumption. */ static apr_status_t ptrans_pre_cleanup(void *dummy) { event_conn_state_t *cs = dummy; if (cs->suspended) { notify_resume(cs, 1); } return APR_SUCCESS; } /* * event_pre_read_request() and event_request_cleanup() track the * current r for a given connection. */ static apr_status_t event_request_cleanup(void *dummy) { conn_rec *c = dummy; event_conn_state_t *cs = ap_get_module_config(c->conn_config, &mpm_event_module); cs->r = NULL; return APR_SUCCESS; } static void event_pre_read_request(request_rec *r, conn_rec *c) { event_conn_state_t *cs = ap_get_module_config(c->conn_config, &mpm_event_module); cs->r = r; cs->sc = ap_get_module_config(ap_server_conf->module_config, &mpm_event_module); apr_pool_cleanup_register(r->pool, c, event_request_cleanup, apr_pool_cleanup_null); } /* * event_post_read_request() tracks the current server config for a * given request. */ static int event_post_read_request(request_rec *r) { conn_rec *c = r->connection; event_conn_state_t *cs = ap_get_module_config(c->conn_config, &mpm_event_module); /* To preserve legacy behaviour (consistent with other MPMs), use * the keepalive timeout from the base server (first on this IP:port) * when none is explicitly configured on this server. */ if (r->server->keep_alive_timeout_set) { cs->sc = ap_get_module_config(r->server->module_config, &mpm_event_module); } else { cs->sc = ap_get_module_config(c->base_server->module_config, &mpm_event_module); } return OK; } /* Forward declare */ static void process_lingering_close(event_conn_state_t *cs); static void update_reqevents_from_sense(event_conn_state_t *cs, int default_sense) { int sense = default_sense; if (cs->pub.sense != CONN_SENSE_DEFAULT) { sense = cs->pub.sense; /* Reset to default for the next round */ cs->pub.sense = CONN_SENSE_DEFAULT; } if (sense == CONN_SENSE_WANT_READ) { cs->pfd.reqevents = APR_POLLIN | APR_POLLHUP; } else { cs->pfd.reqevents = APR_POLLOUT; } /* POLLERR is usually returned event only, but some pollset * backends may require it in reqevents to do the right thing, * so it shouldn't hurt (ignored otherwise). */ cs->pfd.reqevents |= APR_POLLERR; } /* * process one connection in the worker */ static void process_socket(apr_thread_t *thd, apr_pool_t * p, apr_socket_t * sock, event_conn_state_t * cs, int my_child_num, int my_thread_num) { conn_rec *c; long conn_id = ID_FROM_CHILD_THREAD(my_child_num, my_thread_num); int clogging = 0, from_wc_q = 0; apr_status_t rv; int rc = OK; if (cs == NULL) { /* This is a new connection */ listener_poll_type *pt = apr_pcalloc(p, sizeof(*pt)); cs = apr_pcalloc(p, sizeof(event_conn_state_t)); cs->bucket_alloc = apr_bucket_alloc_create(p); ap_create_sb_handle(&cs->sbh, p, my_child_num, my_thread_num); c = ap_run_create_connection(p, ap_server_conf, sock, conn_id, cs->sbh, cs->bucket_alloc); if (!c) { ap_queue_info_push_pool(worker_queue_info, p); return; } apr_atomic_inc32(&connection_count); apr_pool_cleanup_register(c->pool, cs, decrement_connection_count, apr_pool_cleanup_null); ap_set_module_config(c->conn_config, &mpm_event_module, cs); c->current_thread = thd; c->cs = &cs->pub; cs->c = c; cs->p = p; cs->sc = ap_get_module_config(ap_server_conf->module_config, &mpm_event_module); cs->pfd.desc_type = APR_POLL_SOCKET; cs->pfd.desc.s = sock; pt->type = PT_CSD; pt->baton = cs; cs->pfd.client_data = pt; apr_pool_pre_cleanup_register(p, cs, ptrans_pre_cleanup); TO_QUEUE_ELEM_INIT(cs); ap_update_vhost_given_ip(c); rc = ap_pre_connection(c, sock); if (rc != OK && rc != DONE) { ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, APLOGNO(00469) "process_socket: connection aborted"); close_connection(cs); return; } /** * XXX If the platform does not have a usable way of bundling * accept() with a socket readability check, like Win32, * and there are measurable delays before the * socket is readable due to the first data packet arriving, * it might be better to create the cs on the listener thread * with the state set to CONN_STATE_KEEPALIVE * * FreeBSD users will want to enable the HTTP accept filter * module in their kernel for the highest performance * When the accept filter is active, sockets are kept in the * kernel until a HTTP request is received. */ cs->pub.state = CONN_STATE_PROCESSING; cs->pub.sense = CONN_SENSE_DEFAULT; } else { c = cs->c; ap_update_sb_handle(cs->sbh, my_child_num, my_thread_num); notify_resume(cs, 0); c->current_thread = thd; /* Subsequent request on a conn, and thread number is part of ID */ c->id = conn_id; } if (CONN_STATE_IS_LINGERING_CLOSE(cs->pub.state)) { goto lingering_close; } if (cs->pub.state == CONN_STATE_PROCESSING /* If we have an input filter which 'clogs' the input stream, * like mod_ssl used to, lets just do the normal read from input * filters, like the Worker MPM does. Filters that need to write * where they would otherwise read, or read where they would * otherwise write, should set the sense appropriately. */ || c->clogging_input_filters) { process_connection: cs->pub.state = CONN_STATE_PROCESSING; clogging = c->clogging_input_filters; if (clogging) { apr_atomic_inc32(&clogged_count); } rc = ap_run_process_connection(c); if (clogging) { apr_atomic_dec32(&clogged_count); } /* * The process_connection hooks should set the appropriate connection * state upon return, for event MPM to either: * - CONN_STATE_LINGER: do lingering close; * - CONN_STATE_WRITE_COMPLETION: flush pending outputs using Timeout * and wait for next incoming data using KeepAliveTimeout, then come * back to process_connection() hooks; * - CONN_STATE_SUSPENDED: suspend the connection such that it now * interacts with the MPM through suspend/resume_connection() hooks, * and/or registered poll callbacks (PT_USER), and/or registered * timed callbacks triggered by timer events; * - CONN_STATE_ASYNC_WAITIO: wait for read/write-ability of the underlying * socket using Timeout and come back to process_connection() hooks when * ready; * - CONN_STATE_KEEPALIVE: now handled by CONN_STATE_WRITE_COMPLETION * to flush before waiting for next data (that might depend on it). * If a process_connection hook returns an error or no hook sets the state * to one of the above expected value, forcibly close the connection w/ * CONN_STATE_LINGER. This covers the cases where no process_connection * hook executes (DECLINED), or one returns OK w/o touching the state (i.e. * CONN_STATE_PROCESSING remains after the call) which can happen with * third-party modules not updated to work specifically with event MPM * while this was expected to do lingering close unconditionally with * worker or prefork MPMs for instance. */ switch (rc) { case DONE: rc = OK; /* same as OK, fall through */ case OK: if (cs->pub.state == CONN_STATE_PROCESSING) { cs->pub.state = CONN_STATE_LINGER; } else if (cs->pub.state == CONN_STATE_KEEPALIVE) { cs->pub.state = CONN_STATE_WRITE_COMPLETION; } break; } if (rc != OK || (cs->pub.state != CONN_STATE_LINGER && cs->pub.state != CONN_STATE_ASYNC_WAITIO && cs->pub.state != CONN_STATE_WRITE_COMPLETION && cs->pub.state != CONN_STATE_SUSPENDED)) { ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, APLOGNO(10111) "process_socket: connection processing returned %i " "(%sstate %i): closing", rc, rc ? "" : "unexpected ", (int)cs->pub.state); cs->pub.state = CONN_STATE_LINGER; } else if (c->aborted) { cs->pub.state = CONN_STATE_LINGER; } if (cs->pub.state == CONN_STATE_LINGER) { goto lingering_close; } } else if (cs->pub.state == CONN_STATE_WRITE_COMPLETION) { from_wc_q = 1; } if (cs->pub.state == CONN_STATE_ASYNC_WAITIO) { /* Set a read/write timeout for this connection, and let the * event thread poll for read/writeability. */ cs->queue_timestamp = apr_time_now(); notify_suspend(cs); ap_update_child_status(cs->sbh, SERVER_BUSY_READ, NULL); /* Modules might set c->cs->sense to CONN_SENSE_WANT_WRITE, * the default is CONN_SENSE_WANT_READ still. */ update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ); apr_thread_mutex_lock(timeout_mutex); TO_QUEUE_APPEND(cs->sc->io_q, cs); rv = apr_pollset_add(event_pollset, &cs->pfd); if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) { AP_DEBUG_ASSERT(0); TO_QUEUE_REMOVE(cs->sc->io_q, cs); apr_thread_mutex_unlock(timeout_mutex); ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(10503) "process_socket: apr_pollset_add failure in " "CONN_STATE_ASYNC_WAITIO"); close_connection(cs); signal_threads(ST_GRACEFUL); } else { apr_thread_mutex_unlock(timeout_mutex); } return; } if (cs->pub.state == CONN_STATE_WRITE_COMPLETION) { int pending = DECLINED; /* Flush all pending outputs before going to CONN_STATE_KEEPALIVE or * straight to CONN_STATE_PROCESSING if inputs are pending already. */ ap_update_child_status(cs->sbh, SERVER_BUSY_WRITE, NULL); if (from_wc_q) { from_wc_q = 0; /* one shot */ pending = ap_run_output_pending(c); } else if (ap_filter_should_yield(c->output_filters)) { pending = OK; } if (pending == OK) { /* Let the event thread poll for write */ cs->queue_timestamp = apr_time_now(); notify_suspend(cs); /* Add work to pollset. */ cs->pub.sense = CONN_SENSE_DEFAULT; update_reqevents_from_sense(cs, CONN_SENSE_WANT_WRITE); apr_thread_mutex_lock(timeout_mutex); TO_QUEUE_APPEND(cs->sc->wc_q, cs); rv = apr_pollset_add(event_pollset, &cs->pfd); if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) { AP_DEBUG_ASSERT(0); TO_QUEUE_REMOVE(cs->sc->wc_q, cs); apr_thread_mutex_unlock(timeout_mutex); ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03465) "process_socket: apr_pollset_add failure in " "CONN_STATE_WRITE_COMPLETION"); close_connection(cs); signal_threads(ST_GRACEFUL); } else { apr_thread_mutex_unlock(timeout_mutex); } return; } if (pending != DECLINED || c->aborted || c->keepalive != AP_CONN_KEEPALIVE) { cs->pub.state = CONN_STATE_LINGER; goto lingering_close; } if (ap_run_input_pending(c) == OK) { goto process_connection; } if (listener_may_exit) { cs->pub.state = CONN_STATE_LINGER; goto lingering_close; } /* Fall through */ cs->pub.state = CONN_STATE_KEEPALIVE; } if (cs->pub.state == CONN_STATE_KEEPALIVE) { ap_update_child_status(cs->sbh, SERVER_BUSY_KEEPALIVE, NULL); /* It greatly simplifies the logic to use a single timeout value per q * because the new element can just be added to the end of the list and * it will stay sorted in expiration time sequence. If brand new * sockets are sent to the event thread for a readability check, this * will be a slight behavior change - they use the non-keepalive * timeout today. With a normal client, the socket will be readable in * a few milliseconds anyway. */ cs->queue_timestamp = apr_time_now(); notify_suspend(cs); /* Add work to pollset. */ cs->pub.sense = CONN_SENSE_DEFAULT; update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ); apr_thread_mutex_lock(timeout_mutex); TO_QUEUE_APPEND(cs->sc->ka_q, cs); rv = apr_pollset_add(event_pollset, &cs->pfd); if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) { AP_DEBUG_ASSERT(0); TO_QUEUE_REMOVE(cs->sc->ka_q, cs); apr_thread_mutex_unlock(timeout_mutex); ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03093) "process_socket: apr_pollset_add failure for " "keep alive"); close_connection(cs); signal_threads(ST_GRACEFUL); } else { apr_thread_mutex_unlock(timeout_mutex); } return; } if (cs->pub.state == CONN_STATE_SUSPENDED) { cs->c->suspended_baton = cs; apr_atomic_inc32(&suspended_count); notify_suspend(cs); return; } lingering_close: /* CONN_STATE_LINGER[_*] fall through process_lingering_close() */ process_lingering_close(cs); } /* Put a SUSPENDED connection back into a queue. */ static apr_status_t event_resume_suspended (conn_rec *c) { event_conn_state_t* cs = (event_conn_state_t*) c->suspended_baton; if (cs == NULL) { ap_log_cerror (APLOG_MARK, LOG_WARNING, 0, c, APLOGNO(02615) "event_resume_suspended: suspended_baton is NULL"); return APR_EGENERAL; } else if (!cs->suspended) { ap_log_cerror (APLOG_MARK, LOG_WARNING, 0, c, APLOGNO(02616) "event_resume_suspended: Thread isn't suspended"); return APR_EGENERAL; } apr_atomic_dec32(&suspended_count); c->suspended_baton = NULL; if (!CONN_STATE_IS_LINGERING_CLOSE(cs->pub.state)) { cs->queue_timestamp = apr_time_now(); notify_suspend(cs); cs->pub.sense = CONN_SENSE_DEFAULT; cs->pub.state = CONN_STATE_WRITE_COMPLETION; update_reqevents_from_sense(cs, CONN_SENSE_WANT_WRITE); apr_thread_mutex_lock(timeout_mutex); TO_QUEUE_APPEND(cs->sc->wc_q, cs); apr_pollset_add(event_pollset, &cs->pfd); apr_thread_mutex_unlock(timeout_mutex); } else { process_lingering_close(cs); } return OK; } /* conns_this_child has gone to zero or below. See if the admin coded "MaxConnectionsPerChild 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) { ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf, "Stopping process due to MaxConnectionsPerChild"); signal_threads(ST_GRACEFUL); } /* keep going */ conns_this_child = APR_INT32_MAX; } static int close_listeners(int *closed) { if (!*closed) { int i; ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, "closing listeners (connection_count=%u)", apr_atomic_read32(&connection_count)); ap_close_listeners_ex(my_bucket->listeners); dying = 1; ap_scoreboard_image->parent[ap_child_slot].quiescing = 1; for (i = 0; i < threads_per_child; ++i) { ap_update_child_status_from_indexes(ap_child_slot, i, SERVER_GRACEFUL, NULL); } /* wake up the main thread */ kill(ap_my_pid, SIGTERM); ap_queue_info_free_idle_pools(worker_queue_info); ap_queue_interrupt_all(worker_queue); *closed = 1; /* once */ return 1; } ap_log_error(APLOG_MARK, APLOG_TRACE6, 0, ap_server_conf, "closed listeners (connection_count=%u)", apr_atomic_read32(&connection_count)); return 0; } 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. */ } #if HAVE_SERF static apr_status_t s_socket_add(void *user_baton, apr_pollfd_t *pfd, void *serf_baton) { s_baton_t *s = (s_baton_t*)user_baton; /* XXXXX: recycle listener_poll_types */ listener_poll_type *pt = ap_malloc(sizeof(*pt)); pt->type = PT_SERF; pt->baton = serf_baton; pfd->client_data = pt; return apr_pollset_add(s->pollset, pfd); } static apr_status_t s_socket_remove(void *user_baton, apr_pollfd_t *pfd, void *serf_baton) { s_baton_t *s = (s_baton_t*)user_baton; listener_poll_type *pt = pfd->client_data; free(pt); return apr_pollset_remove(s->pollset, pfd); } #endif #if HAVE_SERF static void init_serf(apr_pool_t *p) { s_baton_t *baton = NULL; baton = apr_pcalloc(p, sizeof(*baton)); baton->pollset = event_pollset; /* TODO: subpools, threads, reuse, etc. -- currently use malloc() inside :( */ baton->pool = p; g_serf = serf_context_create_ex(baton, s_socket_add, s_socket_remove, p); ap_register_provider(p, "mpm_serf", "instance", "0", g_serf); } #endif static apr_status_t push_timer2worker(timer_event_t* te) { return ap_queue_push_timer(worker_queue, te); } /* * Pre-condition: cs is neither in event_pollset nor a timeout queue * this function may only be called by the listener */ static apr_status_t push2worker(event_conn_state_t *cs, apr_socket_t *csd, apr_pool_t *ptrans) { apr_status_t rc; if (cs) { csd = cs->pfd.desc.s; ptrans = cs->p; } rc = ap_queue_push_socket(worker_queue, csd, cs, ptrans); if (rc != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_CRIT, rc, ap_server_conf, APLOGNO(00471) "push2worker: ap_queue_push_socket failed"); /* trash the connection; we couldn't queue the connected * socket to a worker */ if (cs) { shutdown_connection(cs); } else { if (csd) { close_socket_nonblocking(csd); } if (ptrans) { ap_queue_info_push_pool(worker_queue_info, ptrans); } } signal_threads(ST_GRACEFUL); } return rc; } /* get_worker: * If *have_idle_worker_p == 0, reserve a worker thread, and set * *have_idle_worker_p = 1. * If *have_idle_worker_p is already 1, will do nothing. * If blocking == 1, block if all workers are currently busy. * If no worker was available immediately, will set *all_busy to 1. * XXX: If there are no workers, we should not block immediately but * XXX: close all keep-alive connections first. */ static void get_worker(int *have_idle_worker_p, int blocking, int *all_busy) { apr_status_t rc; if (*have_idle_worker_p) { /* already reserved a worker thread - must have hit a * transient error on a previous pass */ return; } if (blocking) rc = ap_queue_info_wait_for_idler(worker_queue_info, all_busy); else rc = ap_queue_info_try_get_idler(worker_queue_info); if (rc == APR_SUCCESS || APR_STATUS_IS_EOF(rc)) { *have_idle_worker_p = 1; } else if (!blocking && rc == APR_EAGAIN) { *all_busy = 1; } else { ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf, APLOGNO(00472) "ap_queue_info_wait_for_idler failed. " "Attempting to shutdown process gracefully"); signal_threads(ST_GRACEFUL); } } /* Structures to reuse */ static timer_event_t timer_free_ring; static apr_skiplist *timer_skiplist; static volatile apr_time_t timers_next_expiry; /* Same goal as for TIMEOUT_FUDGE_FACTOR (avoid extra poll calls), but applied * to timers. Since their timeouts are custom (user defined), we can't be too * approximative here (hence using 0.01s). */ #define EVENT_FUDGE_FACTOR apr_time_from_msec(10) /* The following compare function is used by apr_skiplist_insert() to keep the * elements (timers) sorted and provide O(log n) complexity (this is also true * for apr_skiplist_{find,remove}(), but those are not used in MPM event where * inserted timers are not searched nor removed, but with apr_skiplist_pop() * which does use any compare function). It is meant to return 0 when a == b, * <0 when a < b, and >0 when a > b. However apr_skiplist_insert() will not * add duplicates (i.e. a == b), and apr_skiplist_add() is only available in * APR 1.6, yet multiple timers could possibly be created in the same micro- * second (duplicates with regard to apr_time_t); therefore we implement the * compare function to return +1 instead of 0 when compared timers are equal, * thus duplicates are still added after each other (in order of insertion). */ static int timer_comp(void *a, void *b) { apr_time_t t1 = (apr_time_t) ((timer_event_t *)a)->when; apr_time_t t2 = (apr_time_t) ((timer_event_t *)b)->when; AP_DEBUG_ASSERT(t1); AP_DEBUG_ASSERT(t2); return ((t1 < t2) ? -1 : 1); } static apr_thread_mutex_t *g_timer_skiplist_mtx; static timer_event_t * event_get_timer_event(apr_time_t t, ap_mpm_callback_fn_t *cbfn, void *baton, int insert, apr_array_header_t *pfds) { timer_event_t *te; apr_time_t now = (t < 0) ? 0 : apr_time_now(); /* oh yeah, and make locking smarter/fine grained. */ apr_thread_mutex_lock(g_timer_skiplist_mtx); if (!APR_RING_EMPTY(&timer_free_ring.link, timer_event_t, link)) { te = APR_RING_FIRST(&timer_free_ring.link); APR_RING_REMOVE(te, link); } else { te = apr_skiplist_alloc(timer_skiplist, sizeof(timer_event_t)); APR_RING_ELEM_INIT(te, link); } te->cbfunc = cbfn; te->baton = baton; te->canceled = 0; te->when = now + t; te->pfds = pfds; if (insert) { apr_time_t next_expiry; /* Okay, add sorted by when.. */ apr_skiplist_insert(timer_skiplist, te); /* Cheaply update the global timers_next_expiry with this event's * if it expires before. */ next_expiry = timers_next_expiry; if (!next_expiry || next_expiry > te->when + EVENT_FUDGE_FACTOR) { timers_next_expiry = te->when; /* Unblock the poll()ing listener for it to update its timeout. */ if (listener_is_wakeable) { apr_pollset_wakeup(event_pollset); } } } apr_thread_mutex_unlock(g_timer_skiplist_mtx); return te; } static apr_status_t event_register_timed_callback_ex(apr_time_t t, ap_mpm_callback_fn_t *cbfn, void *baton, apr_array_header_t *pfds) { event_get_timer_event(t, cbfn, baton, 1, pfds); return APR_SUCCESS; } static apr_status_t event_register_timed_callback(apr_time_t t, ap_mpm_callback_fn_t *cbfn, void *baton) { event_register_timed_callback_ex(t, cbfn, baton, NULL); return APR_SUCCESS; } static apr_status_t event_cleanup_poll_callback(void *data) { apr_status_t final_rc = APR_SUCCESS; apr_array_header_t *pfds = data; int i; for (i = 0; i < pfds->nelts; i++) { apr_pollfd_t *pfd = (apr_pollfd_t *)pfds->elts + i; if (pfd->client_data) { apr_status_t rc; rc = apr_pollset_remove(event_pollset, pfd); if (rc != APR_SUCCESS && !APR_STATUS_IS_NOTFOUND(rc)) { final_rc = rc; } pfd->client_data = NULL; } } return final_rc; } static apr_status_t event_register_poll_callback_ex(apr_pool_t *p, const apr_array_header_t *pfds, ap_mpm_callback_fn_t *cbfn, ap_mpm_callback_fn_t *tofn, void *baton, apr_time_t timeout) { socket_callback_baton_t *scb = apr_pcalloc(p, sizeof(*scb)); listener_poll_type *pt = apr_palloc(p, sizeof(*pt)); apr_status_t rc, final_rc = APR_SUCCESS; int i; pt->type = PT_USER; pt->baton = scb; scb->cbfunc = cbfn; scb->user_baton = baton; scb->pfds = apr_array_copy(p, pfds); apr_pool_pre_cleanup_register(p, scb->pfds, event_cleanup_poll_callback); for (i = 0; i < scb->pfds->nelts; i++) { apr_pollfd_t *pfd = (apr_pollfd_t *)scb->pfds->elts + i; if (pfd->reqevents) { if (pfd->reqevents & APR_POLLIN) { pfd->reqevents |= APR_POLLHUP; } pfd->reqevents |= APR_POLLERR; pfd->client_data = pt; } else { pfd->client_data = NULL; } } if (timeout > 0) { /* XXX: This cancel timer event can fire before the pollset is updated */ scb->cancel_event = event_get_timer_event(timeout, tofn, baton, 1, scb->pfds); } for (i = 0; i < scb->pfds->nelts; i++) { apr_pollfd_t *pfd = (apr_pollfd_t *)scb->pfds->elts + i; if (pfd->client_data) { rc = apr_pollset_add(event_pollset, pfd); if (rc != APR_SUCCESS) { final_rc = rc; } } } return final_rc; } static apr_status_t event_register_poll_callback(apr_pool_t *p, const apr_array_header_t *pfds, ap_mpm_callback_fn_t *cbfn, void *baton) { return event_register_poll_callback_ex(p, pfds, cbfn, NULL, /* no timeout function */ baton, 0 /* no timeout */); } /* * Flush data and close our side of the connection, then drain incoming data. * If the latter would block put the connection in one of the linger timeout * queues to be called back when ready, and repeat until it's closed by peer. * Only to be called in the worker thread, and since it's in immediate call * stack, we can afford a comfortable buffer size to consume data quickly. * Pre-condition: cs is not in any timeout queue and not in the pollset, * timeout_mutex is not locked */ #define LINGERING_BUF_SIZE (32 * 1024) static void process_lingering_close(event_conn_state_t *cs) { apr_socket_t *csd = ap_get_conn_socket(cs->c); char dummybuf[LINGERING_BUF_SIZE]; apr_size_t nbytes; apr_status_t rv; struct timeout_queue *q; ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, cs->c, "lingering close from state %i", (int)cs->pub.state); AP_DEBUG_ASSERT(CONN_STATE_IS_LINGERING_CLOSE(cs->pub.state)); if (!cs->linger_started) { cs->pub.state = CONN_STATE_LINGER; cs->linger_started = 1; /* defer_lingering_close() may have bumped lingering_count already */ if (!cs->deferred_linger) { apr_atomic_inc32(&lingering_count); } apr_socket_timeout_set(csd, apr_time_from_sec(SECONDS_TO_LINGER)); if (ap_start_lingering_close(cs->c)) { notify_suspend(cs); close_connection(cs); return; } /* All nonblocking from now, no need for APR_INCOMPLETE_READ either */ apr_socket_timeout_set(csd, 0); apr_socket_opt_set(csd, APR_INCOMPLETE_READ, 0); /* * If some module requested a shortened waiting period, only wait for * 2s (SECONDS_TO_LINGER). This is useful for mitigating certain * DoS attacks. */ if (apr_table_get(cs->c->notes, "short-lingering-close")) { cs->pub.state = CONN_STATE_LINGER_SHORT; } else { cs->pub.state = CONN_STATE_LINGER_NORMAL; } cs->pub.sense = CONN_SENSE_DEFAULT; notify_suspend(cs); /* One timestamp/duration for the whole lingering close time. * XXX: This makes the (short_)linger_q not sorted/ordered by expiring * timeouts whenever multiple schedules are necessary (EAGAIN below), * but we probabaly don't care since these connections do not count * for connections_above_limit() and all of them will be killed when * busy or gracefully stopping anyway. */ cs->queue_timestamp = apr_time_now(); } do { nbytes = sizeof(dummybuf); rv = apr_socket_recv(csd, dummybuf, &nbytes); } while (rv == APR_SUCCESS); if (!APR_STATUS_IS_EAGAIN(rv)) { close_connection(cs); return; } /* (Re)queue the connection to come back when readable */ update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ); q = (cs->pub.state == CONN_STATE_LINGER_SHORT) ? short_linger_q : linger_q; apr_thread_mutex_lock(timeout_mutex); TO_QUEUE_APPEND(q, cs); rv = apr_pollset_add(event_pollset, &cs->pfd); if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) { AP_DEBUG_ASSERT(0); TO_QUEUE_REMOVE(q, cs); apr_thread_mutex_unlock(timeout_mutex); ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03092) "process_lingering_close: apr_pollset_add failure"); close_connection(cs); signal_threads(ST_GRACEFUL); return; } apr_thread_mutex_unlock(timeout_mutex); } /* call 'func' for all elements of 'q' above 'expiry'. * Pre-condition: timeout_mutex must already be locked * Post-condition: timeout_mutex will be locked again */ static void process_timeout_queue(struct timeout_queue *q, apr_time_t expiry, int (*func)(event_conn_state_t *)) { apr_uint32_t total = 0, count; event_conn_state_t *first, *cs, *last; struct event_conn_state_t trash; struct timeout_queue *qp; apr_status_t rv; if (!*q->total) { return; } APR_RING_INIT(&trash.timeout_list, event_conn_state_t, timeout_list); for (qp = q; qp; qp = qp->next) { count = 0; cs = first = last = APR_RING_FIRST(&qp->head); while (cs != APR_RING_SENTINEL(&qp->head, event_conn_state_t, timeout_list)) { /* Trash the entry if: * - no expiry was given (zero means all), or * - it expired (according to the queue timeout), or * - the system clock skewed in the past: no entry should be * registered above the given expiry (~now) + the queue * timeout, we won't keep any here (eg. for centuries). * * Otherwise stop, no following entry will match thanks to the * single timeout per queue (entries are added to the end!). * This allows maintenance in O(1). */ if (expiry && cs->queue_timestamp + qp->timeout > expiry && cs->queue_timestamp < expiry + qp->timeout) { /* Since this is the next expiring entry of this queue, update * the global queues_next_expiry if it's later than this one. */ apr_time_t elem_expiry = cs->queue_timestamp + qp->timeout; apr_time_t next_expiry = queues_next_expiry; if (!next_expiry || next_expiry > elem_expiry + TIMEOUT_FUDGE_FACTOR) { queues_next_expiry = elem_expiry; } break; } last = cs; rv = apr_pollset_remove(event_pollset, &cs->pfd); if (rv != APR_SUCCESS && !APR_STATUS_IS_NOTFOUND(rv)) { AP_DEBUG_ASSERT(0); ap_log_cerror(APLOG_MARK, APLOG_ERR, rv, cs->c, APLOGNO(00473) "apr_pollset_remove failed"); } cs = APR_RING_NEXT(cs, timeout_list); count++; } if (!count) continue; APR_RING_UNSPLICE(first, last, timeout_list); APR_RING_SPLICE_TAIL(&trash.timeout_list, first, last, event_conn_state_t, timeout_list); AP_DEBUG_ASSERT(*q->total >= count && qp->count >= count); *q->total -= count; qp->count -= count; total += count; } if (!total) return; apr_thread_mutex_unlock(timeout_mutex); first = APR_RING_FIRST(&trash.timeout_list); do { cs = APR_RING_NEXT(first, timeout_list); TO_QUEUE_ELEM_INIT(first); func(first); first = cs; } while (--total); apr_thread_mutex_lock(timeout_mutex); } static void process_keepalive_queue(apr_time_t expiry) { /* If all workers are busy, we kill older keep-alive connections so * that they may connect to another process. */ if (!expiry && *keepalive_q->total) { ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf, "All workers are busy or dying, will shutdown %u " "keep-alive connections", *keepalive_q->total); } process_timeout_queue(keepalive_q, expiry, shutdown_connection); } static void * APR_THREAD_FUNC listener_thread(apr_thread_t * thd, void *dummy) { apr_status_t rc; proc_info *ti = dummy; int process_slot = ti->pslot; struct process_score *ps = ap_get_scoreboard_process(process_slot); int closed = 0; int have_idle_worker = 0; apr_time_t last_log; last_log = apr_time_now(); free(ti); #if HAVE_SERF init_serf(apr_thread_pool_get(thd)); #endif /* Unblock the signal used to wake this thread up, and set a handler for * it. */ apr_signal(LISTENER_SIGNAL, dummy_signal_handler); unblock_signal(LISTENER_SIGNAL); for (;;) { timer_event_t *te; const apr_pollfd_t *out_pfd; apr_int32_t num = 0; apr_interval_time_t timeout; socket_callback_baton_t *user_chain; apr_time_t now, expiry = -1; int workers_were_busy = 0; if (conns_this_child <= 0) check_infinite_requests(); if (listener_may_exit) { int first_close = close_listeners(&closed); if (terminate_mode == ST_UNGRACEFUL || apr_atomic_read32(&connection_count) == 0) break; /* Don't wait in poll() for the first close (i.e. dying now), we * want to maintain the queues and schedule defer_linger_chain ASAP * to kill kept-alive connection and shutdown the workers and child * faster. */ if (first_close) { goto do_maintenance; /* with expiry == -1 */ } } if (APLOGtrace6(ap_server_conf)) { now = apr_time_now(); /* trace log status every second */ if (now - last_log > apr_time_from_sec(1)) { ap_log_error(APLOG_MARK, APLOG_TRACE6, 0, ap_server_conf, "connections: %u (waitio:%u write-completion:%u" "keep-alive:%u lingering:%u suspended:%u clogged:%u), " "workers: %u/%u shutdown", apr_atomic_read32(&connection_count), apr_atomic_read32(waitio_q->total), apr_atomic_read32(write_completion_q->total), apr_atomic_read32(keepalive_q->total), apr_atomic_read32(&lingering_count), apr_atomic_read32(&suspended_count), apr_atomic_read32(&clogged_count), apr_atomic_read32(&threads_shutdown), threads_per_child); last_log = now; } } #if HAVE_SERF rc = serf_context_prerun(g_serf); if (rc != APR_SUCCESS) { /* TODO: what should we do here? ugh. */ } #endif /* Start with an infinite poll() timeout and update it according to * the next expiring timer or queue entry. If there are none, either * the listener is wakeable and it can poll() indefinitely until a wake * up occurs, otherwise periodic checks (maintenance, shutdown, ...) * must be performed. */ now = apr_time_now(); timeout = -1; /* Push expired timers to a worker, the first remaining one determines * the maximum time to poll() below, if any. */ expiry = timers_next_expiry; if (expiry && expiry < now) { apr_thread_mutex_lock(g_timer_skiplist_mtx); while ((te = apr_skiplist_peek(timer_skiplist))) { if (te->when > now) { timers_next_expiry = te->when; timeout = te->when - now; break; } apr_skiplist_pop(timer_skiplist, NULL); if (!te->canceled) { if (te->pfds) { /* remove all sockets from the pollset */ apr_pool_cleanup_run(te->pfds->pool, te->pfds, event_cleanup_poll_callback); } push_timer2worker(te); } else { APR_RING_INSERT_TAIL(&timer_free_ring.link, te, timer_event_t, link); } } if (!te) { timers_next_expiry = 0; } apr_thread_mutex_unlock(g_timer_skiplist_mtx); } /* Same for queues, use their next expiry, if any. */ expiry = queues_next_expiry; if (expiry && (timeout < 0 || expiry <= now || timeout > expiry - now)) { timeout = expiry > now ? expiry - now : 0; } /* When non-wakeable, don't wait more than 100 ms, in any case. */ #define NON_WAKEABLE_POLL_TIMEOUT apr_time_from_msec(100) if (!listener_is_wakeable && (timeout < 0 || timeout > NON_WAKEABLE_POLL_TIMEOUT)) { timeout = NON_WAKEABLE_POLL_TIMEOUT; } else if (timeout > 0) { /* apr_pollset_poll() might round down the timeout to milliseconds, * let's forcibly round up here to never return before the timeout. */ timeout = apr_time_from_msec( apr_time_as_msec(timeout + apr_time_from_msec(1) - 1) ); } ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, ap_server_conf, "polling with timeout=%" APR_TIME_T_FMT " queues_timeout=%" APR_TIME_T_FMT " timers_timeout=%" APR_TIME_T_FMT, timeout, queues_next_expiry - now, timers_next_expiry - now); rc = apr_pollset_poll(event_pollset, timeout, &num, &out_pfd); if (rc != APR_SUCCESS) { if (!APR_STATUS_IS_EINTR(rc) && !APR_STATUS_IS_TIMEUP(rc)) { ap_log_error(APLOG_MARK, APLOG_CRIT, rc, ap_server_conf, APLOGNO(03267) "apr_pollset_poll failed. Attempting to " "shutdown process gracefully"); signal_threads(ST_GRACEFUL); } num = 0; } if (APLOGtrace7(ap_server_conf)) { now = apr_time_now(); ap_log_error(APLOG_MARK, APLOG_TRACE7, rc, ap_server_conf, "polled with num=%u exit=%d/%d conns=%d" " queues_timeout=%" APR_TIME_T_FMT " timers_timeout=%" APR_TIME_T_FMT, num, listener_may_exit, dying, apr_atomic_read32(&connection_count), queues_next_expiry - now, timers_next_expiry - now); } /* XXX possible optimization: stash the current time for use as * r->request_time for new requests or queues maintenance */ for (user_chain = NULL; num; --num, ++out_pfd) { listener_poll_type *pt = (listener_poll_type *) out_pfd->client_data; if (pt->type == PT_CSD) { /* one of the sockets is readable */ event_conn_state_t *cs = (event_conn_state_t *) pt->baton; struct timeout_queue *remove_from_q = NULL; /* don't wait for a worker for a keepalive request or * lingering close processing. */ int blocking = 0; switch (cs->pub.state) { case CONN_STATE_WRITE_COMPLETION: remove_from_q = cs->sc->wc_q; blocking = 1; break; case CONN_STATE_ASYNC_WAITIO: cs->pub.state = CONN_STATE_PROCESSING; remove_from_q = cs->sc->io_q; blocking = 1; break; case CONN_STATE_KEEPALIVE: cs->pub.state = CONN_STATE_PROCESSING; remove_from_q = cs->sc->ka_q; break; case CONN_STATE_LINGER_NORMAL: remove_from_q = linger_q; break; case CONN_STATE_LINGER_SHORT: remove_from_q = short_linger_q; break; default: ap_log_error(APLOG_MARK, APLOG_CRIT, rc, ap_server_conf, APLOGNO(03096) "event_loop: unexpected state %d", cs->pub.state); ap_assert(0); } if (remove_from_q) { apr_thread_mutex_lock(timeout_mutex); TO_QUEUE_REMOVE(remove_from_q, cs); rc = apr_pollset_remove(event_pollset, &cs->pfd); apr_thread_mutex_unlock(timeout_mutex); /* * Some of the pollset backends, like KQueue or Epoll * automagically remove the FD if the socket is closed, * therefore, we can accept _SUCCESS or _NOTFOUND, * and we still want to keep going */ if (rc != APR_SUCCESS && !APR_STATUS_IS_NOTFOUND(rc)) { AP_DEBUG_ASSERT(0); ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf, APLOGNO(03094) "pollset remove failed"); close_connection(cs); signal_threads(ST_GRACEFUL); break; } /* If we don't get a worker immediately (nonblocking), we * close the connection; the client can re-connect to a * different process for keepalive, and for lingering close * the connection will be shutdown so the choice is to favor * incoming/alive connections. */ get_worker(&have_idle_worker, blocking, &workers_were_busy); if (!have_idle_worker) { shutdown_connection(cs); } else if (push2worker(cs, NULL, NULL) == APR_SUCCESS) { have_idle_worker = 0; } } } else if (pt->type == PT_ACCEPT && !listeners_disabled()) { /* A Listener Socket is ready for an accept() */ if (workers_were_busy) { disable_listensocks(); ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(03268) "All workers busy, not accepting new conns " "in this process"); } else if (connections_above_limit(&workers_were_busy)) { disable_listensocks(); ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(03269) "Too many open connections (%u, idlers %u), " "not accepting new conns in this process", apr_atomic_read32(&connection_count), ap_queue_info_num_idlers(worker_queue_info)); } else if (!listener_may_exit) { void *csd = NULL; ap_listen_rec *lr = (ap_listen_rec *) pt->baton; apr_pool_t *ptrans; /* Pool for per-transaction stuff */ ap_queue_info_pop_pool(worker_queue_info, &ptrans); if (ptrans == NULL) { /* create a new transaction pool for each accepted socket */ apr_allocator_t *allocator = NULL; rc = apr_allocator_create(&allocator); if (rc == APR_SUCCESS) { apr_allocator_max_free_set(allocator, ap_max_mem_free); rc = apr_pool_create_ex(&ptrans, pconf, NULL, allocator); if (rc == APR_SUCCESS) { apr_pool_tag(ptrans, "transaction"); apr_allocator_owner_set(allocator, ptrans); } } if (rc != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_CRIT, rc, ap_server_conf, APLOGNO(03097) "Failed to create transaction pool"); if (allocator) { apr_allocator_destroy(allocator); } resource_shortage = 1; signal_threads(ST_GRACEFUL); continue; } } get_worker(&have_idle_worker, 1, &workers_were_busy); rc = lr->accept_func(&csd, lr, ptrans); /* later we trash rv and rely on csd to indicate * success/failure */ AP_DEBUG_ASSERT(rc == APR_SUCCESS || !csd); if (rc == APR_EGENERAL) { /* E[NM]FILE, ENOMEM, etc */ resource_shortage = 1; signal_threads(ST_GRACEFUL); } else if (ap_accept_error_is_nonfatal(rc)) { ap_log_error(APLOG_MARK, APLOG_DEBUG, rc, ap_server_conf, "accept() on client socket failed"); } if (csd != NULL) { conns_this_child--; if (push2worker(NULL, csd, ptrans) == APR_SUCCESS) { have_idle_worker = 0; } } else { ap_queue_info_push_pool(worker_queue_info, ptrans); } } } /* if:else on pt->type */ #if HAVE_SERF else if (pt->type == PT_SERF) { /* send socket to serf. */ /* XXXX: this doesn't require get_worker() */ serf_event_trigger(g_serf, pt->baton, out_pfd); } #endif else if (pt->type == PT_USER) { socket_callback_baton_t *baton = pt->baton; if (baton->cancel_event) { baton->cancel_event->canceled = 1; } /* We only signal once per N sockets with this baton, * and after this loop to avoid any race/lifetime issue * with the user callback being called while we handle * the same baton multiple times here. */ if (!baton->signaled) { baton->signaled = 1; baton->next = user_chain; user_chain = baton; } } } /* for processing poll */ /* Time to handle user callbacks chained above */ while (user_chain) { socket_callback_baton_t *baton = user_chain; user_chain = user_chain->next; baton->next = NULL; /* remove all sockets from the pollset */ apr_pool_cleanup_run(baton->pfds->pool, baton->pfds, event_cleanup_poll_callback); /* masquerade as a timer event that is firing */ te = event_get_timer_event(-1 /* fake timer */, baton->cbfunc, baton->user_baton, 0, /* don't insert it */ NULL /* no associated socket callback */); push_timer2worker(te); } /* We process the timeout queues here only when the global * queues_next_expiry is passed. This happens accurately since * adding to the queues (in workers) can only decrease this expiry, * while latest ones are only taken into account here (in listener) * during queues' processing, with the lock held. This works both * with and without wake-ability. */ expiry = queues_next_expiry; do_maintenance: if (expiry && expiry < (now = apr_time_now())) { ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, ap_server_conf, "queues maintenance with timeout=%" APR_TIME_T_FMT, expiry > 0 ? expiry - now : -1); apr_thread_mutex_lock(timeout_mutex); /* Steps below will recompute this. */ queues_next_expiry = 0; /* Step 1: keepalive queue timeouts are closed */ if (workers_were_busy || dying) { process_keepalive_queue(0); /* kill'em all \m/ */ } else { process_keepalive_queue(now); } /* Step 2: waitio queue timeouts are flushed */ process_timeout_queue(waitio_q, now, defer_lingering_close); /* Step 3: write completion queue timeouts are flushed */ process_timeout_queue(write_completion_q, now, defer_lingering_close); /* Step 4: normal lingering close queue timeouts are closed */ if (dying && linger_q->timeout > short_linger_q->timeout) { /* Dying, force short timeout for normal lingering close */ linger_q->timeout = short_linger_q->timeout; } process_timeout_queue(linger_q, now, shutdown_connection); /* Step 5: short lingering close queue timeouts are closed */ process_timeout_queue(short_linger_q, now, shutdown_connection); apr_thread_mutex_unlock(timeout_mutex); ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, ap_server_conf, "queues maintained with timeout=%" APR_TIME_T_FMT, queues_next_expiry > now ? queues_next_expiry - now : -1); ps->wait_io = apr_atomic_read32(waitio_q->total); ps->write_completion = apr_atomic_read32(write_completion_q->total); ps->keep_alive = apr_atomic_read32(keepalive_q->total); ps->lingering_close = apr_atomic_read32(&lingering_count); ps->suspended = apr_atomic_read32(&suspended_count); ps->connections = apr_atomic_read32(&connection_count); } else if ((workers_were_busy || dying) && apr_atomic_read32(keepalive_q->total)) { apr_thread_mutex_lock(timeout_mutex); process_keepalive_queue(0); /* kill'em all \m/ */ apr_thread_mutex_unlock(timeout_mutex); ps->keep_alive = 0; } /* If there are some lingering closes to defer (to a worker), schedule * them now. We might wakeup a worker spuriously if another one empties * defer_linger_chain in the meantime, but there also may be no active * or all busy workers for an undefined time. In any case a deferred * lingering close can't starve if we do that here since the chain is * filled only above in the listener and it's emptied only in the * worker(s); thus a NULL here means it will stay so while the listener * waits (possibly indefinitely) in poll(). */ if (defer_linger_chain) { get_worker(&have_idle_worker, 0, &workers_were_busy); if (have_idle_worker && defer_linger_chain /* re-test */ && push2worker(NULL, NULL, NULL) == APR_SUCCESS) { have_idle_worker = 0; } } if (!workers_were_busy && should_enable_listensocks()) { enable_listensocks(); } } /* listener main loop */ ap_queue_term(worker_queue); apr_thread_exit(thd, APR_SUCCESS); return NULL; } /* * During graceful shutdown, if there are more running worker threads than * open connections, exit one worker thread. * * return 1 if thread should exit, 0 if it should continue running. */ static int worker_thread_should_exit_early(void) { for (;;) { apr_uint32_t conns = apr_atomic_read32(&connection_count); apr_uint32_t dead = apr_atomic_read32(&threads_shutdown); apr_uint32_t newdead; AP_DEBUG_ASSERT(dead <= threads_per_child); if (conns >= threads_per_child - dead) return 0; newdead = dead + 1; if (apr_atomic_cas32(&threads_shutdown, newdead, dead) == dead) { /* * No other thread has exited in the mean time, safe to exit * this one. */ return 1; } } } /* 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->pslot; int thread_slot = ti->tslot; 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].tid = apr_os_thread_current(); ap_scoreboard_image->servers[process_slot][thread_slot].generation = retained->mpm->my_generation; ap_update_child_status_from_indexes(process_slot, thread_slot, SERVER_STARTING, NULL); for (;;) { apr_socket_t *csd = NULL; event_conn_state_t *cs; timer_event_t *te = NULL; apr_pool_t *ptrans; /* Pool for per-transaction stuff */ if (!is_idle) { rv = ap_queue_info_set_idle(worker_queue_info, NULL); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(03270) "ap_queue_info_set_idle failed. Attempting to " "shutdown process gracefully."); signal_threads(ST_GRACEFUL); break; } /* A new idler may have changed connections_above_limit(), * let the listener know and decide. */ if (listener_is_wakeable && should_enable_listensocks()) { apr_pollset_wakeup(event_pollset); } is_idle = 1; } ap_update_child_status_from_indexes(process_slot, thread_slot, dying ? SERVER_GRACEFUL : SERVER_READY, NULL); worker_pop: if (workers_may_exit) { break; } if (dying && worker_thread_should_exit_early()) { break; } rv = ap_queue_pop_something(worker_queue, &csd, (void **)&cs, &ptrans, &te); 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, APLOGNO(03099) "ap_queue_pop_socket failed"); } continue; } if (te != NULL) { te->cbfunc(te->baton); { apr_thread_mutex_lock(g_timer_skiplist_mtx); APR_RING_INSERT_TAIL(&timer_free_ring.link, te, timer_event_t, link); apr_thread_mutex_unlock(g_timer_skiplist_mtx); } } else { is_idle = 0; if (csd != NULL) { worker_sockets[thread_slot] = csd; process_socket(thd, ptrans, csd, cs, process_slot, thread_slot); worker_sockets[thread_slot] = NULL; } } /* If there are deferred lingering closes, handle them now. */ while (!workers_may_exit) { cs = defer_linger_chain; if (!cs) { break; } if (apr_atomic_casptr((void *)&defer_linger_chain, cs->chain, cs) != cs) { /* Race lost, try again */ continue; } cs->chain = NULL; AP_DEBUG_ASSERT(cs->pub.state == CONN_STATE_LINGER); worker_sockets[thread_slot] = csd = cs->pfd.desc.s; process_socket(thd, cs->p, csd, cs, process_slot, thread_slot); worker_sockets[thread_slot] = NULL; } } ap_update_child_status_from_indexes(process_slot, thread_slot, dying ? SERVER_DEAD : SERVER_GRACEFUL, 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 *) ap_malloc(sizeof(proc_info)); my_info->pslot = my_child_num; my_info->tslot = -1; /* listener thread doesn't have a thread slot */ rv = ap_thread_create(&ts->listener, thread_attr, listener_thread, my_info, pruntime); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(00474) "ap_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); } static void setup_threads_runtime(void) { apr_status_t rv; ap_listen_rec *lr; apr_pool_t *pskip = NULL; int max_recycled_pools = -1, i; const int good_methods[] = { APR_POLLSET_KQUEUE, APR_POLLSET_PORT, APR_POLLSET_EPOLL }; /* XXX: K-A or lingering close connection included in the async factor */ const apr_uint32_t async_factor = worker_factor / WORKER_FACTOR_SCALE; const apr_uint32_t pollset_size = (apr_uint32_t)num_listensocks + (apr_uint32_t)threads_per_child * (async_factor > 2 ? async_factor : 2); int pollset_flags; /* Event's skiplist operations will happen concurrently with other modules' * runtime so they need their own pool for allocations, and its lifetime * should be at least the one of the connections (ptrans). Thus pskip is * created as a subpool of pconf like/before ptrans (before so that it's * destroyed after). In forked mode pconf is never destroyed so we are good * anyway, but in ONE_PROCESS mode this ensures that the skiplist works * from connection/ptrans cleanups (even after pchild is destroyed). */ apr_pool_create(&pskip, pconf); apr_pool_tag(pskip, "mpm_skiplist"); apr_thread_mutex_create(&g_timer_skiplist_mtx, APR_THREAD_MUTEX_DEFAULT, pskip); APR_RING_INIT(&timer_free_ring.link, timer_event_t, link); apr_skiplist_init(&timer_skiplist, pskip); apr_skiplist_set_compare(timer_skiplist, timer_comp, timer_comp); /* All threads (listener, workers) and synchronization objects (queues, * pollset, mutexes...) created here should have at least the lifetime of * the connections they handle (i.e. ptrans). We can't use this thread's * self pool because all these objects survive it, nor use pchild or pconf * directly because this starter thread races with other modules' runtime, * nor finally pchild (or subpool thereof) because it is killed explicitly * before pconf (thus connections/ptrans can live longer, which matters in * ONE_PROCESS mode). So this leaves us with a subpool of pconf, created * before any ptrans hence destroyed after. */ apr_pool_create(&pruntime, pconf); apr_pool_tag(pruntime, "mpm_runtime"); /* We must create the fd queues before we start up the listener * and worker threads. */ rv = ap_queue_create(&worker_queue, threads_per_child, pruntime); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03100) "ap_queue_create() failed"); clean_child_exit(APEXIT_CHILDFATAL); } if (ap_max_mem_free != APR_ALLOCATOR_MAX_FREE_UNLIMITED) { /* If we want to conserve memory, let's not keep an unlimited number of * pools & allocators. * XXX: This should probably be a separate config directive */ max_recycled_pools = threads_per_child * 3 / 4 ; } rv = ap_queue_info_create(&worker_queue_info, pruntime, threads_per_child, max_recycled_pools); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03101) "ap_queue_info_create() failed"); clean_child_exit(APEXIT_CHILDFATAL); } /* Create the timeout mutex and main pollset before the listener * thread starts. */ rv = apr_thread_mutex_create(&timeout_mutex, APR_THREAD_MUTEX_DEFAULT, pruntime); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03102) "creation of the timeout mutex failed."); clean_child_exit(APEXIT_CHILDFATAL); } /* Create the main pollset. When APR_POLLSET_WAKEABLE is asked we account * for the wakeup pipe explicitely with pollset_size+1 because some pollset * implementations don't do it implicitely in APR. */ pollset_flags = APR_POLLSET_THREADSAFE | APR_POLLSET_NOCOPY | APR_POLLSET_WAKEABLE | APR_POLLSET_NODEFAULT; for (i = 0; i < sizeof(good_methods) / sizeof(good_methods[0]); i++) { rv = apr_pollset_create_ex(&event_pollset, pollset_size + 1, pruntime, pollset_flags, good_methods[i]); if (rv == APR_SUCCESS) { listener_is_wakeable = 1; break; } } if (rv != APR_SUCCESS) { pollset_flags &= ~APR_POLLSET_NODEFAULT; rv = apr_pollset_create(&event_pollset, pollset_size + 1, pruntime, pollset_flags); if (rv == APR_SUCCESS) { listener_is_wakeable = 1; } else { pollset_flags &= ~APR_POLLSET_WAKEABLE; rv = apr_pollset_create(&event_pollset, pollset_size, pruntime, pollset_flags); } } if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03103) "apr_pollset_create with Thread Safety failed."); clean_child_exit(APEXIT_CHILDFATAL); } /* Add listeners to the main pollset */ listener_pollfd = apr_pcalloc(pruntime, num_listensocks * sizeof(apr_pollfd_t)); for (i = 0, lr = my_bucket->listeners; lr; lr = lr->next, i++) { apr_pollfd_t *pfd; listener_poll_type *pt; AP_DEBUG_ASSERT(i < num_listensocks); pfd = &listener_pollfd[i]; pfd->reqevents = APR_POLLIN | APR_POLLHUP | APR_POLLERR; #ifdef APR_POLLEXCL /* If APR_POLLEXCL is available, use it to prevent the thundering * herd issue. The listening sockets are potentially polled by all * the children at the same time, when new connections arrive this * avoids all of them to be woken up while most would get EAGAIN * on accept(). */ pfd->reqevents |= APR_POLLEXCL; #endif pfd->desc_type = APR_POLL_SOCKET; pfd->desc.s = lr->sd; pt = apr_pcalloc(pruntime, sizeof(*pt)); pfd->client_data = pt; pt->type = PT_ACCEPT; pt->baton = lr; apr_socket_opt_set(pfd->desc.s, APR_SO_NONBLOCK, 1); apr_pollset_add(event_pollset, pfd); lr->accept_func = ap_unixd_accept; } worker_sockets = apr_pcalloc(pruntime, threads_per_child * sizeof(apr_socket_t *)); } /* 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 my_child_num = ts->child_num_arg; proc_info *my_info; apr_status_t rv; int threads_created = 0; int listener_started = 0; int prev_threads_created; int loops, i; ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(02471) "start_threads: Using %s (%swakeable)", apr_pollset_method_name(event_pollset), listener_is_wakeable ? "" : "not "); loops = prev_threads_created = 0; while (1) { /* threads_per_child does not include the listener thread */ for (i = 0; i < threads_per_child; i++) { int status = ap_scoreboard_image->servers[my_child_num][i].status; if (status != SERVER_DEAD) { continue; } my_info = (proc_info *) ap_malloc(sizeof(proc_info)); my_info->pslot = my_child_num; my_info->tslot = i; /* 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 = ap_thread_create(&threads[i], thread_attr, worker_thread, my_info, pruntime); if (rv != APR_SUCCESS) { ap_update_child_status_from_indexes(my_child_num, i, SERVER_DEAD, NULL); ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03104) "ap_thread_create: unable to create worker thread"); /* Let the parent decide how bad this really is by returning * APEXIT_CHILDSICK. If threads were created already let them * stop cleanly first to avoid deadlocks in clean_child_exit(), * just stop creating new ones here (but set resource_shortage * to return APEXIT_CHILDSICK still when the child exists). */ if (threads_created) { resource_shortage = 1; signal_threads(ST_GRACEFUL); if (!listener_started) { workers_may_exit = 1; ap_queue_term(worker_queue); /* wake up main POD thread too */ kill(ap_my_pid, SIGTERM); } apr_thread_exit(thd, APR_SUCCESS); return NULL; } 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 == 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, APLOGNO(03271) "child %" APR_PID_T_FMT " isn't taking over " "slots very quickly (%d of %d)", ap_my_pid, threads_created, 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 (!dying) { apr_sleep(apr_time_from_msec(500)); if (dying || ++iter > 10) { break; } /* listener has not stopped accepting yet */ ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf, "listener has not stopped accepting yet (%d iter)", iter); wakeup_listener(); } if (iter > 10) { ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00475) "the listener thread didn't stop accepting"); } else { rv = apr_thread_join(&thread_rv, listener); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(00476) "apr_thread_join: unable to join listener thread"); } } } for (i = 0; i < threads_per_child; i++) { if (threads[i]) { /* if we ever created this thread */ rv = apr_thread_join(&thread_rv, threads[i]); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(00477) "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, APLOGNO(00478) "apr_thread_join: unable to join the start " "thread"); } } static void child_main(int child_num_arg, int child_bucket) { apr_thread_t **threads; apr_status_t rv; thread_starter *ts; apr_threadattr_t *thread_attr; apr_thread_t *start_thread_id; int i; /* for benefit of any hooks that run as this child initializes */ retained->mpm->mpm_state = AP_MPMQ_STARTING; ap_my_pid = getpid(); ap_child_slot = child_num_arg; 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_pool_create(&pchild, pconf); apr_pool_tag(pchild, "pchild"); #if AP_HAS_THREAD_LOCAL if (!one_process) { apr_thread_t *thd = NULL; if ((rv = ap_thread_main_create(&thd, pchild))) { ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(10377) "Couldn't initialize child main thread"); clean_child_exit(APEXIT_CHILDFATAL); } } #endif /* close unused listeners and pods */ for (i = 0; i < retained->mpm->num_buckets; i++) { if (i != child_bucket) { ap_close_listeners_ex(retained->buckets[i].listeners); ap_mpm_podx_close(retained->buckets[i].pod); } } /*stuff to do before we switch id's, so we have permissions. */ ap_reopen_scoreboard(pchild, NULL, 0); /* done with init critical section */ if (ap_run_drop_privileges(pchild, ap_server_conf)) { clean_child_exit(APEXIT_CHILDFATAL); } /* 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. Let's also do this before * child_init() hooks are called and possibly create threads that * otherwise could "steal" (implicitly) MPM's signals. */ rv = apr_setup_signal_thread(); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(00479) "Couldn't initialize signal thread"); clean_child_exit(APEXIT_CHILDFATAL); } /* For rand() users (e.g. skiplist). */ srand((unsigned int)apr_time_now()); ap_run_child_init(pchild, ap_server_conf); if (ap_max_requests_per_child) { conns_this_child = ap_max_requests_per_child; } else { /* coding a value of zero means infinity */ conns_this_child = APR_INT32_MAX; } /* Setup threads */ /* Globals used by signal_threads() so to be initialized before */ setup_threads_runtime(); /* 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 = ap_calloc(threads_per_child, sizeof(apr_thread_t *)); ts = 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) { rv = apr_threadattr_stacksize_set(thread_attr, ap_thread_stacksize); if (rv != APR_SUCCESS && rv != APR_ENOTIMPL) { ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf, APLOGNO(02436) "WARNING: ThreadStackSize of %" APR_SIZE_T_FMT " is " "inappropriate, using default", ap_thread_stacksize); } } ts->threads = threads; ts->listener = NULL; ts->child_num_arg = child_num_arg; ts->threadattr = thread_attr; rv = ap_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, APLOGNO(00480) "ap_thread_create: unable to create worker thread"); /* let the parent decide how bad this really is */ clean_child_exit(APEXIT_CHILDSICK); } retained->mpm->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); /* helps us terminate a little more quickly than the dispatch of the * signal thread; beats the Pipe of Death and the browsers */ signal_threads(ST_UNGRACEFUL); /* 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 MaxConnectionsPerChild) it will send us SIGTERM */ apr_signal(SIGTERM, dummy_signal_handler); unblock_signal(SIGTERM); /* Watch for any messages from the parent over the POD */ while (1) { rv = ap_mpm_podx_check(my_bucket->pod); if (rv == AP_MPM_PODX_NORESTART) { /* see if termination was triggered while we slept */ switch (terminate_mode) { case ST_GRACEFUL: rv = AP_MPM_PODX_GRACEFUL; break; case ST_UNGRACEFUL: rv = AP_MPM_PODX_RESTART; break; } } if (rv == AP_MPM_PODX_GRACEFUL || rv == AP_MPM_PODX_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_MPM_PODX_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). */ ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf, "%s termination received, joining workers", rv == AP_MPM_PODX_GRACEFUL ? "graceful" : "ungraceful"); join_workers(ts->listener, threads); ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf, "%s termination, workers joined, exiting", rv == AP_MPM_PODX_GRACEFUL ? "graceful" : "ungraceful"); } free(threads); clean_child_exit(resource_shortage ? APEXIT_CHILDSICK : 0); } static int make_child(server_rec * s, int slot, int bucket) { int pid; if (slot + 1 > retained->max_daemon_used) { retained->max_daemon_used = slot + 1; } if (ap_scoreboard_image->parent[slot].pid != 0) { /* XXX replace with assert or remove ? */ ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(03455) "BUG: Scoreboard slot %d should be empty but is " "in use by pid %" APR_PID_T_FMT, slot, ap_scoreboard_image->parent[slot].pid); return -1; } if (one_process) { my_bucket = &retained->buckets[0]; event_note_child_started(slot, getpid()); child_main(slot, 0); /* NOTREACHED */ ap_assert(0); return -1; } if ((pid = fork()) == -1) { ap_log_error(APLOG_MARK, APLOG_ERR, errno, s, APLOGNO(00481) "fork: Unable to fork new process"); /* fork didn't succeed. There's no need to touch the scoreboard; * if we were trying to replace a failed child process, then * server_main_loop() marked its workers SERVER_DEAD, and if * we were trying to replace a child process that exited normally, * its worker_thread()s left SERVER_DEAD or SERVER_GRACEFUL behind. */ /* 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) { #if AP_HAS_THREAD_LOCAL ap_thread_current_after_fork(); #endif my_bucket = &retained->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(00482) "processor unbind failed"); #endif RAISE_SIGSTOP(MAKE_CHILD); apr_signal(SIGTERM, just_die); child_main(slot, bucket); /* NOTREACHED */ ap_assert(0); return -1; } event_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 < server_limit; ++i) { if (ap_scoreboard_image->parent[i].pid != 0) { continue; } if (make_child(ap_server_conf, i, i % retained->mpm->num_buckets) < 0) { break; } --number_to_start; } } static void perform_idle_server_maintenance(int child_bucket, int *max_daemon_used) { int num_buckets = retained->mpm->num_buckets; int idle_thread_count = 0; process_score *ps; int free_length = 0; int free_slots[MAX_SPAWN_RATE]; int last_non_dead = -1; int active_thread_count = 0; int i, j; for (i = 0; i < server_limit; ++i) { if (num_buckets > 1 && (i % num_buckets) != child_bucket) { /* We only care about child_bucket in this call */ continue; } if (i >= retained->max_daemon_used && free_length == retained->idle_spawn_rate[child_bucket]) { /* short cut if all active processes have been examined and * enough empty scoreboard slots have been found */ break; } ps = &ap_scoreboard_image->parent[i]; if (ps->pid != 0) { int child_threads_active = 0; if (ps->quiescing == 1) { ps->quiescing = 2; retained->active_daemons--; ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, "Child %d quiescing: pid %d, gen %d, " "active %d/%d, total %d/%d/%d", i, (int)ps->pid, (int)ps->generation, retained->active_daemons, active_daemons_limit, retained->total_daemons, retained->max_daemon_used, server_limit); } for (j = 0; j < threads_per_child; j++) { int status = ap_scoreboard_image->servers[i][j].status; /* 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 && !ps->quiescing && !ps->not_accepting && ps->generation == retained->mpm->my_generation) { ++idle_thread_count; } if (status >= SERVER_READY && status < SERVER_GRACEFUL) { ++child_threads_active; } } active_thread_count += child_threads_active; if (child_threads_active == threads_per_child) { had_healthy_child = 1; } last_non_dead = i; } else if (free_length < retained->idle_spawn_rate[child_bucket]) { free_slots[free_length++] = i; } } if (*max_daemon_used < last_non_dead + 1) { *max_daemon_used = last_non_dead + 1; } if (retained->sick_child_detected) { if (had_healthy_child) { /* Assume this is a transient error, even though it may not be. Leave * the server up in case it is able to serve some requests or the * problem will be resolved. */ retained->sick_child_detected = 0; } else if (child_bucket < num_buckets - 1) { /* check for had_healthy_child up to the last child bucket */ return; } else { /* looks like a basket case, as no child ever fully initialized; give up. */ retained->mpm->shutdown_pending = 1; child_fatal = 1; ap_log_error(APLOG_MARK, APLOG_ALERT, 0, ap_server_conf, APLOGNO(02324) "A resource shortage or other unrecoverable failure " "was encountered before any child process initialized " "successfully... httpd is exiting!"); /* the child already logged the failure details */ return; } } AP_DEBUG_ASSERT(retained->active_daemons <= retained->total_daemons && retained->total_daemons <= retained->max_daemon_used && retained->max_daemon_used <= server_limit); if (idle_thread_count > max_spare_threads / num_buckets) { /* * Child processes that we ask to shut down won't die immediately * but may stay around for a long time when they finish their * requests. If the server load changes many times, many such * gracefully finishing processes may accumulate, filling up the * scoreboard. To avoid running out of scoreboard entries, we * don't shut down more processes if there are stopping ones * already (i.e. active_daemons != total_daemons) and not enough * slack space in the scoreboard for a graceful restart. * * XXX It would be nice if we could * XXX - kill processes without keepalive connections first * XXX - tell children to stop accepting new connections, and * XXX depending on server load, later be able to resurrect them * or kill them */ int do_kill = (retained->active_daemons == retained->total_daemons || (server_limit - retained->total_daemons > active_daemons_limit)); ap_log_error(APLOG_MARK, APLOG_TRACE5, 0, ap_server_conf, "%shutting down one child: " "active %d/%d, total %d/%d/%d, " "idle threads %d, max workers %d", (do_kill) ? "S" : "Not s", retained->active_daemons, active_daemons_limit, retained->total_daemons, retained->max_daemon_used, server_limit, idle_thread_count, max_workers); if (do_kill) { ap_mpm_podx_signal(retained->buckets[child_bucket].pod, AP_MPM_PODX_GRACEFUL); } else { /* Wait for dying daemon(s) to exit */ } retained->idle_spawn_rate[child_bucket] = 1; } else if (idle_thread_count < min_spare_threads / num_buckets) { if (active_thread_count >= max_workers / num_buckets) { if (0 == idle_thread_count) { if (!retained->maxclients_reported) { ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(00484) "server reached MaxRequestWorkers setting, " "consider raising the MaxRequestWorkers " "setting"); retained->maxclients_reported = 1; } } else { if (!retained->near_maxclients_reported) { ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(10159) "server is within MinSpareThreads of " "MaxRequestWorkers, consider raising the " "MaxRequestWorkers setting"); retained->near_maxclients_reported = 1; } } retained->idle_spawn_rate[child_bucket] = 1; } else if (free_length == 0) { /* scoreboard is full, can't fork */ ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(03490) "scoreboard is full, not at MaxRequestWorkers." "Increase ServerLimit."); retained->idle_spawn_rate[child_bucket] = 1; } else { if (free_length > retained->idle_spawn_rate[child_bucket]) { free_length = retained->idle_spawn_rate[child_bucket]; } if (free_length + retained->active_daemons > active_daemons_limit) { if (retained->active_daemons < active_daemons_limit) { free_length = active_daemons_limit - retained->active_daemons; } else { ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf, "server is at active daemons limit, spawning " "of %d children cancelled: active %d/%d, " "total %d/%d/%d, rate %d", free_length, retained->active_daemons, active_daemons_limit, retained->total_daemons, retained->max_daemon_used, server_limit, retained->idle_spawn_rate[child_bucket]); /* reset the spawning rate and prevent its growth below */ retained->idle_spawn_rate[child_bucket] = 1; ++retained->hold_off_on_exponential_spawning; free_length = 0; } } if (retained->idle_spawn_rate[child_bucket] >= 8) { ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf, APLOGNO(00486) "server seems busy, (you may need " "to increase StartServers, ThreadsPerChild " "or Min/MaxSpareThreads), " "spawning %d children, there are around %d idle " "threads, %d active children, and %d children " "that are shutting down", free_length, idle_thread_count, retained->active_daemons, retained->total_daemons); } for (i = 0; i < free_length; ++i) { int slot = free_slots[i]; if (make_child(ap_server_conf, slot, child_bucket) < 0) { continue; } if (*max_daemon_used < slot + 1) { *max_daemon_used = slot + 1; } } /* 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[child_bucket] < max_spawn_rate_per_bucket) { int new_rate = retained->idle_spawn_rate[child_bucket] * 2; if (new_rate > max_spawn_rate_per_bucket) { new_rate = max_spawn_rate_per_bucket; } retained->idle_spawn_rate[child_bucket] = new_rate; } } } else { retained->idle_spawn_rate[child_bucket] = 1; } } static void server_main_loop(int remaining_children_to_start) { int num_buckets = retained->mpm->num_buckets; int max_daemon_used = 0; int successive_kills = 0; int child_slot; apr_exit_why_e exitwhy; int status, processed_status; apr_proc_t pid; int i; while (!retained->mpm->restart_pending && !retained->mpm->shutdown_pending) { ap_wait_or_timeout(&exitwhy, &status, &pid, pconf, ap_server_conf); 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->shutdown_pending = 1; child_fatal = 1; /* * total_daemons counting will be off now, but as we * are shutting down, that is not an issue anymore. */ return; } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, ap_server_conf, APLOGNO(00487) "Ignoring fatal error in child of previous " "generation (pid %ld).", (long)pid.pid); retained->sick_child_detected = 1; } } else if (processed_status == APEXIT_CHILDSICK) { /* tell perform_idle_server_maintenance to check into this * on the next timer pop */ retained->sick_child_detected = 1; } /* non-fatal death... note that it's gone in the scoreboard. */ if (child_slot >= 0) { event_note_child_stopped(child_slot, 0, 0); if (processed_status == APEXIT_CHILDSICK) { /* resource shortage, minimize the fork rate */ retained->idle_spawn_rate[child_slot % num_buckets] = 1; } else if (remaining_children_to_start) { /* we're still doing a 1-for-1 replacement of dead * children with new children */ make_child(ap_server_conf, child_slot, child_slot % num_buckets); --remaining_children_to_start; } } #if APR_HAS_OTHER_CHILD else if (apr_proc_other_child_alert(&pid, APR_OC_REASON_DEATH, status) == 0) { /* 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(00488) "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. If a child is * killed by a signal (faulting) we want to restart it ASAP * though, up to 3 successive faults or we stop this until * a timeout happens again (to avoid the flood of fork()ed * processes that keep being killed early). */ if (child_slot < 0 || !APR_PROC_CHECK_SIGNALED(exitwhy)) { continue; } if (++successive_kills >= 3) { if (successive_kills % 10 == 3) { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, ap_server_conf, APLOGNO(10392) "children are killed successively!"); } continue; } ++remaining_children_to_start; } else { successive_kills = 0; } 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; } max_daemon_used = 0; for (i = 0; i < num_buckets; i++) { perform_idle_server_maintenance(i, &max_daemon_used); } retained->max_daemon_used = max_daemon_used; } } static int event_run(apr_pool_t * _pconf, apr_pool_t * plog, server_rec * s) { ap_listen_rec **listen_buckets = NULL; int num_buckets = retained->mpm->num_buckets; int remaining_children_to_start; apr_status_t rv; int i; ap_log_pid(pconf, ap_pid_fname); /* On first startup create gen_pool to satisfy the lifetime of the * parent's PODs and listeners; on restart stop the children from the * previous generation and clear gen_pool for the next one. */ if (!retained->gen_pool) { apr_pool_create(&retained->gen_pool, ap_pglobal); } else { if (retained->mpm->was_graceful) { /* wake up the children...time to die. But we'll have more soon */ for (i = 0; i < num_buckets; i++) { ap_mpm_podx_killpg(retained->buckets[i].pod, active_daemons_limit, AP_MPM_PODX_GRACEFUL); } } 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. */ for (i = 0; i < num_buckets; i++) { ap_mpm_podx_killpg(retained->buckets[i].pod, active_daemons_limit, AP_MPM_PODX_RESTART); } ap_reclaim_child_processes(1, /* Start with SIGTERM */ event_note_child_stopped); } apr_pool_clear(retained->gen_pool); retained->buckets = NULL; /* advance to the next generation */ /* XXX: we really need to make sure this new generation number isn't in * use by any of the previous children. */ ++retained->mpm->my_generation; } /* On graceful restart, preserve the scoreboard and the listeners buckets. * When ungraceful, clear the scoreboard and set num_buckets to zero to let * ap_duplicate_listeners() below determine how many are needed/configured. */ 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; } num_buckets = (one_process) ? 1 : 0; /* one_process => one bucket */ retained->mpm->num_buckets = 0; /* reset idle_spawn_rate below */ } /* Now on for the new generation. */ ap_scoreboard_image->global->running_generation = retained->mpm->my_generation; ap_unixd_mpm_set_signals(pconf, one_process); if ((rv = ap_duplicate_listeners(retained->gen_pool, ap_server_conf, &listen_buckets, &num_buckets))) { ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(03273) "could not duplicate listeners"); return !OK; } retained->buckets = apr_pcalloc(retained->gen_pool, num_buckets * sizeof(event_child_bucket)); for (i = 0; i < num_buckets; i++) { if (!one_process /* no POD in one_process mode */ && (rv = ap_mpm_podx_open(retained->gen_pool, &retained->buckets[i].pod))) { ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(03274) "could not open pipe-of-death"); return !OK; } retained->buckets[i].listeners = listen_buckets[i]; } if (retained->mpm->max_buckets < num_buckets) { int new_max, *new_ptr; new_max = retained->mpm->max_buckets * 2; if (new_max < num_buckets) { new_max = num_buckets; } new_ptr = (int *)apr_palloc(ap_pglobal, new_max * sizeof(int)); if (retained->mpm->num_buckets) /* idle_spawn_rate NULL at startup */ memcpy(new_ptr, retained->idle_spawn_rate, retained->mpm->num_buckets * sizeof(int)); retained->idle_spawn_rate = new_ptr; retained->mpm->max_buckets = new_max; } if (retained->mpm->num_buckets < num_buckets) { int rate_max = 1; /* If new buckets are added, set their idle spawn rate to * the highest so far, so that they get filled as quickly * as the existing ones. */ for (i = 0; i < retained->mpm->num_buckets; i++) { if (rate_max < retained->idle_spawn_rate[i]) { rate_max = retained->idle_spawn_rate[i]; } } for (/* up to date i */; i < num_buckets; i++) { retained->idle_spawn_rate[i] = rate_max; } } retained->mpm->num_buckets = num_buckets; /* Don't thrash since num_buckets depends on the * system and the number of online CPU cores... */ if (active_daemons_limit < num_buckets) active_daemons_limit = num_buckets; if (ap_daemons_to_start < num_buckets) ap_daemons_to_start = num_buckets; /* We want to create as much children at a time as the number of buckets, * so to optimally accept connections (evenly distributed across buckets). * Thus min_spare_threads should at least maintain num_buckets children, * and max_spare_threads allow num_buckets more children w/o triggering * immediately (e.g. num_buckets idle threads margin, one per bucket). */ if (min_spare_threads < threads_per_child * (num_buckets - 1) + num_buckets) min_spare_threads = threads_per_child * (num_buckets - 1) + num_buckets; if (max_spare_threads < min_spare_threads + (threads_per_child + 1) * num_buckets) max_spare_threads = min_spare_threads + (threads_per_child + 1) * num_buckets; max_spawn_rate_per_bucket = (MAX_SPAWN_RATE + num_buckets - 1) / num_buckets; if (max_spawn_rate_per_bucket < 1) { max_spawn_rate_per_bucket = 1; } /* If we're doing a graceful_restart then we're going to see a lot * of children exiting immediately when we get into the main loop * below (because we just sent them AP_SIG_GRACEFUL). This happens pretty * rapidly... and for each one that exits we may start a new one, until * there are at least min_spare_threads idle threads, counting across * all children. But we may be permitted to start more children 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 > active_daemons_limit) { remaining_children_to_start = active_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(00489) "%s configured -- resuming normal operations", ap_get_server_description()); ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf, APLOGNO(00490) "Server built: %s", ap_get_server_built()); ap_log_command_line(plog, s); ap_log_mpm_common(s); retained->mpm->mpm_state = AP_MPMQ_RUNNING; server_main_loop(remaining_children_to_start); 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... */ for (i = 0; i < num_buckets; i++) { ap_mpm_podx_killpg(retained->buckets[i].pod, active_daemons_limit, AP_MPM_PODX_RESTART); } ap_reclaim_child_processes(1, /* Start with SIGTERM */ event_note_child_stopped); if (!child_fatal) { /* 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(00491) "caught SIGTERM, shutting down"); } return DONE; } if (retained->mpm->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(); for (i = 0; i < num_buckets; i++) { ap_mpm_podx_killpg(retained->buckets[i].pod, active_daemons_limit, AP_MPM_PODX_GRACEFUL); } ap_relieve_child_processes(event_note_child_stopped); if (!child_fatal) { /* 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(00492) "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 */ apr_sleep(apr_time_from_sec(1)); /* Relieve any children which have now exited */ ap_relieve_child_processes(event_note_child_stopped); active_children = 0; for (index = 0; index < retained->max_daemon_used; ++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. */ for (i = 0; i < num_buckets; i++) { ap_mpm_podx_killpg(retained->buckets[i].pod, active_daemons_limit, AP_MPM_PODX_RESTART); } ap_reclaim_child_processes(1, event_note_child_stopped); return DONE; } /* we've been told to restart */ if (one_process) { /* not worth thinking about */ return DONE; } if (!retained->mpm->is_ungraceful) { ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00493) "%s received. Doing graceful restart", AP_SIG_GRACEFUL_STRING); } else { ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00494) "SIGHUP received. Attempting to restart"); } return OK; } static void setup_slave_conn(conn_rec *c, void *csd) { event_conn_state_t *mcs; event_conn_state_t *cs; mcs = ap_get_module_config(c->master->conn_config, &mpm_event_module); cs = apr_pcalloc(c->pool, sizeof(*cs)); cs->c = c; cs->r = NULL; cs->sc = mcs->sc; cs->suspended = 0; cs->p = c->pool; cs->bucket_alloc = c->bucket_alloc; cs->pfd = mcs->pfd; cs->pub = mcs->pub; cs->pub.state = CONN_STATE_PROCESSING; cs->pub.sense = CONN_SENSE_DEFAULT; c->cs = &(cs->pub); ap_set_module_config(c->conn_config, &mpm_event_module, cs); } static int event_pre_connection(conn_rec *c, void *csd) { if (c->master && (!c->cs || c->cs == c->master->cs)) { setup_slave_conn(c, csd); } return OK; } static int event_protocol_switch(conn_rec *c, request_rec *r, server_rec *s, const char *protocol) { if (!r && s) { /* connection based switching of protocol, set the correct server * configuration, so that timeouts, keepalives and such are used * for the server that the connection was switched on. * Normally, we set this on post_read_request, but on a protocol * other than http/1.1, this might never happen. */ event_conn_state_t *cs; cs = ap_get_module_config(c->conn_config, &mpm_event_module); cs->sc = ap_get_module_config(s->module_config, &mpm_event_module); } return DECLINED; } /* 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 event_open_logs(apr_pool_t * p, apr_pool_t * plog, apr_pool_t * ptemp, server_rec * s) { int startup = 0; int level_flags = 0; 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), APLOGNO(03272) "no listening sockets available, shutting down"); return !OK; } return OK; } static int event_pre_config(apr_pool_t * pconf, apr_pool_t * plog, apr_pool_t * ptemp) { int no_detach, debug, foreground; apr_status_t rv; const char *userdata_key = "mpm_event_module"; int test_atomics = 0; 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"); } 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->mpm->baton = retained; if (retained->mpm->module_loads) { test_atomics = 1; } } else if (retained->mpm->baton != retained) { /* If the MPM changes on restart, be ungraceful */ retained->mpm->baton = retained; retained->mpm->was_graceful = 0; } retained->mpm->mpm_state = AP_MPMQ_STARTING; ++retained->mpm->module_loads; /* test once for correct operation of fdqueue */ if (test_atomics || retained->mpm->module_loads == 2) { static apr_uint32_t foo1, foo2; apr_atomic_set32(&foo1, 100); foo2 = apr_atomic_add32(&foo1, -10); if (foo2 != 100 || foo1 != 90) { ap_log_error(APLOG_MARK, APLOG_CRIT, 0, NULL, APLOGNO(02405) "atomics not working as expected - add32 of negative number"); return HTTP_INTERNAL_SERVER_ERROR; } } /* sigh, want this only the second time around */ if (retained->mpm->module_loads == 2) { rv = apr_pollset_create(&event_pollset, 1, plog, APR_POLLSET_THREADSAFE | APR_POLLSET_NOCOPY); if (rv != APR_SUCCESS) { ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL, APLOGNO(00495) "Couldn't create a Thread Safe Pollset. " "Is it supported on your platform?" "Also check system or user limits!"); return HTTP_INTERNAL_SERVER_ERROR; } apr_pollset_destroy(event_pollset); 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(00496) "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; min_spare_threads = DEFAULT_MIN_FREE_DAEMON * DEFAULT_THREADS_PER_CHILD; max_spare_threads = DEFAULT_MAX_FREE_DAEMON * DEFAULT_THREADS_PER_CHILD; server_limit = DEFAULT_SERVER_LIMIT; thread_limit = DEFAULT_THREAD_LIMIT; active_daemons_limit = server_limit; threads_per_child = DEFAULT_THREADS_PER_CHILD; max_workers = active_daemons_limit * threads_per_child; defer_linger_chain = NULL; had_healthy_child = 0; ap_extended_status = 0; event_pollset = NULL; worker_queue_info = NULL; listener_os_thread = NULL; listensocks_disabled = 0; listener_is_wakeable = 0; return OK; } static int event_post_config(apr_pool_t *pconf, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s) { struct { struct timeout_queue *tail, *q; apr_hash_t *hash; } io, wc, ka; /* Not needed in pre_config stage */ if (ap_state_query(AP_SQ_MAIN_STATE) == AP_SQ_MS_CREATE_PRE_CONFIG) { return OK; } io.hash = apr_hash_make(ptemp); wc.hash = apr_hash_make(ptemp); ka.hash = apr_hash_make(ptemp); io.tail = wc.tail = ka.tail = NULL; linger_q = TO_QUEUE_MAKE(pconf, apr_time_from_sec(MAX_SECS_TO_LINGER), NULL); short_linger_q = TO_QUEUE_MAKE(pconf, apr_time_from_sec(SECONDS_TO_LINGER), NULL); for (; s; s = s->next) { event_srv_cfg *sc = apr_pcalloc(pconf, sizeof *sc); ap_set_module_config(s->module_config, &mpm_event_module, sc); if (!io.tail) { /* The main server uses the global queues */ io.q = TO_QUEUE_MAKE(pconf, s->timeout, NULL); apr_hash_set(io.hash, &s->timeout, sizeof s->timeout, io.q); io.tail = waitio_q = io.q; wc.q = TO_QUEUE_MAKE(pconf, s->timeout, NULL); apr_hash_set(wc.hash, &s->timeout, sizeof s->timeout, wc.q); wc.tail = write_completion_q = wc.q; ka.q = TO_QUEUE_MAKE(pconf, s->keep_alive_timeout, NULL); apr_hash_set(ka.hash, &s->keep_alive_timeout, sizeof s->keep_alive_timeout, ka.q); ka.tail = keepalive_q = ka.q; } else { /* The vhosts use any existing queue with the same timeout, * or their own queue(s) if there isn't */ io.q = apr_hash_get(io.hash, &s->timeout, sizeof s->timeout); if (!io.q) { io.q = TO_QUEUE_MAKE(pconf, s->timeout, io.tail); apr_hash_set(io.hash, &s->timeout, sizeof s->timeout, io.q); io.tail = io.tail->next = io.q; } wc.q = apr_hash_get(wc.hash, &s->timeout, sizeof s->timeout); if (!wc.q) { wc.q = TO_QUEUE_MAKE(pconf, s->timeout, wc.tail); apr_hash_set(wc.hash, &s->timeout, sizeof s->timeout, wc.q); wc.tail = wc.tail->next = wc.q; } ka.q = apr_hash_get(ka.hash, &s->keep_alive_timeout, sizeof s->keep_alive_timeout); if (!ka.q) { ka.q = TO_QUEUE_MAKE(pconf, s->keep_alive_timeout, ka.tail); apr_hash_set(ka.hash, &s->keep_alive_timeout, sizeof s->keep_alive_timeout, ka.q); ka.tail = ka.tail->next = ka.q; } } sc->io_q = io.q; sc->wc_q = wc.q; sc->ka_q = ka.q; } return OK; } static int event_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(00497) "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(00498) "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(00499) "WARNING: ServerLimit of %d not allowed, " "increasing to 1.", server_limit); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00500) "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(00501) "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 (thread_limit > MAX_THREAD_LIMIT) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00502) "WARNING: ThreadLimit of %d exceeds compile-time " "limit of %d threads, decreasing to %d.", thread_limit, MAX_THREAD_LIMIT, MAX_THREAD_LIMIT); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00503) "ThreadLimit of %d exceeds compile-time limit " "of %d, decreasing to match", thread_limit, MAX_THREAD_LIMIT); } thread_limit = MAX_THREAD_LIMIT; } else if (thread_limit < 1) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00504) "WARNING: ThreadLimit of %d not allowed, " "increasing to 1.", thread_limit); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00505) "ThreadLimit of %d not allowed, increasing to 1", thread_limit); } thread_limit = 1; } /* you cannot change ThreadLimit across a restart; ignore * any such attempts */ if (!retained->first_thread_limit) { retained->first_thread_limit = thread_limit; } else if (thread_limit != retained->first_thread_limit) { /* don't need a startup console version here */ ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00506) "changing ThreadLimit to %d from original value of %d " "not allowed during restart", thread_limit, retained->first_thread_limit); thread_limit = retained->first_thread_limit; } if (threads_per_child > thread_limit) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00507) "WARNING: ThreadsPerChild of %d exceeds ThreadLimit " "of %d threads, decreasing to %d. " "To increase, please see the ThreadLimit directive.", threads_per_child, thread_limit, thread_limit); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00508) "ThreadsPerChild of %d exceeds ThreadLimit " "of %d, decreasing to match", threads_per_child, thread_limit); } threads_per_child = thread_limit; } else if (threads_per_child < 1) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00509) "WARNING: ThreadsPerChild of %d not allowed, " "increasing to 1.", threads_per_child); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00510) "ThreadsPerChild of %d not allowed, increasing to 1", threads_per_child); } threads_per_child = 1; } if (max_workers < threads_per_child) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00511) "WARNING: MaxRequestWorkers of %d is less than " "ThreadsPerChild of %d, increasing to %d. " "MaxRequestWorkers must be at least as large " "as the number of threads in a single server.", max_workers, threads_per_child, threads_per_child); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00512) "MaxRequestWorkers of %d is less than ThreadsPerChild " "of %d, increasing to match", max_workers, threads_per_child); } max_workers = threads_per_child; } active_daemons_limit = max_workers / threads_per_child; if (max_workers % threads_per_child) { int tmp_max_workers = active_daemons_limit * threads_per_child; if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00513) "WARNING: MaxRequestWorkers of %d is not an integer " "multiple of ThreadsPerChild of %d, decreasing to nearest " "multiple %d, for a maximum of %d servers.", max_workers, threads_per_child, tmp_max_workers, active_daemons_limit); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00514) "MaxRequestWorkers of %d is not an integer multiple " "of ThreadsPerChild of %d, decreasing to nearest " "multiple %d", max_workers, threads_per_child, tmp_max_workers); } max_workers = tmp_max_workers; } if (active_daemons_limit > server_limit) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00515) "WARNING: MaxRequestWorkers of %d would require %d servers " "and would exceed ServerLimit of %d, decreasing to %d. " "To increase, please see the ServerLimit directive.", max_workers, active_daemons_limit, server_limit, server_limit * threads_per_child); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00516) "MaxRequestWorkers of %d would require %d servers and " "exceed ServerLimit of %d, decreasing to %d", max_workers, active_daemons_limit, server_limit, server_limit * threads_per_child); } active_daemons_limit = server_limit; } /* ap_daemons_to_start > active_daemons_limit checked in ap_mpm_run() */ if (ap_daemons_to_start < 1) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00517) "WARNING: StartServers of %d not allowed, " "increasing to 1.", ap_daemons_to_start); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00518) "StartServers of %d not allowed, increasing to 1", ap_daemons_to_start); } ap_daemons_to_start = 1; } if (min_spare_threads < 1) { if (startup) { ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00519) "WARNING: MinSpareThreads of %d not allowed, " "increasing to 1 to avoid almost certain server " "failure. Please read the documentation.", min_spare_threads); } else { ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00520) "MinSpareThreads of %d not allowed, increasing to 1", min_spare_threads); } min_spare_threads = 1; } /* max_spare_threads < min_spare_threads + threads_per_child * checked in ap_mpm_run() */ return OK; } static void event_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 }; one_process = 0; ap_force_set_tz(p); ap_hook_open_logs(event_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(event_pre_config, NULL, NULL, APR_HOOK_REALLY_FIRST); ap_hook_post_config(event_post_config, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_check_config(event_check_config, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_mpm(event_run, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_mpm_query(event_query, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_mpm_register_timed_callback(event_register_timed_callback, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_mpm_register_poll_callback(event_register_poll_callback, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_mpm_register_poll_callback_timeout(event_register_poll_callback_ex, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_pre_read_request(event_pre_read_request, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_post_read_request(event_post_read_request, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_mpm_get_name(event_get_name, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_mpm_resume_suspended(event_resume_suspended, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_pre_connection(event_pre_connection, NULL, NULL, APR_HOOK_REALLY_FIRST); ap_hook_protocol_switch(event_protocol_switch, 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); 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_workers(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(00521) "MaxClients is deprecated, use MaxRequestWorkers " "instead."); } max_workers = atoi(arg); 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; } threads_per_child = 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 char *set_thread_limit(cmd_parms * cmd, void *dummy, const char *arg) { const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } thread_limit = atoi(arg); return NULL; } static const char *set_worker_factor(cmd_parms * cmd, void *dummy, const char *arg) { double val; char *endptr; const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); if (err != NULL) { return err; } val = strtod(arg, &endptr); if (*endptr) return "error parsing value"; if (val <= 0) return "AsyncRequestWorkerFactor argument must be a positive number"; worker_factor = val * WORKER_FACTOR_SCALE; if (worker_factor < WORKER_FACTOR_SCALE) { worker_factor = WORKER_FACTOR_SCALE; } return NULL; } static const command_rec event_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("ServerLimit", set_server_limit, NULL, RSRC_CONF, "Maximum number of child processes for this run of Apache"), 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_workers, NULL, RSRC_CONF, "Deprecated name of MaxRequestWorkers"), AP_INIT_TAKE1("MaxRequestWorkers", set_max_workers, 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("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_INIT_TAKE1("AsyncRequestWorkerFactor", set_worker_factor, NULL, RSRC_CONF, "How many additional connects will be accepted per idle " "worker thread"), AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND, {NULL} }; AP_DECLARE_MODULE(mpm_event) = { 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 */ event_cmds, /* command apr_table_t */ event_hooks /* register_hooks */ };