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Diffstat (limited to 'server/mpm/event/event.c')
| -rw-r--r-- | server/mpm/event/event.c | 3912 |
1 files changed, 3912 insertions, 0 deletions
diff --git a/server/mpm/event/event.c b/server/mpm/event/event.c new file mode 100644 index 0000000..4cfb09c --- /dev/null +++ b/server/mpm/event/event.c @@ -0,0 +1,3912 @@ +/* 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 <stdlib.h> + +#if APR_HAVE_UNISTD_H +#include <unistd.h> +#endif +#if APR_HAVE_SYS_SOCKET_H +#include <sys/socket.h> +#endif +#if APR_HAVE_SYS_WAIT_H +#include <sys/wait.h> +#endif +#ifdef HAVE_SYS_PROCESSOR_H +#include <sys/processor.h> /* for bindprocessor() */ +#endif + +#if !APR_HAS_THREADS +#error The 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 <signal.h> +#include <limits.h> /* for INT_MAX */ + + +/* Limit on the total --- clients will be locked out if more servers than + * this are needed. It is intended solely to keep the server from crashing + * when things get out of hand. + * + * We keep a hard maximum number of servers, for two reasons --- first off, + * in case something goes seriously wrong, we want to stop the fork bomb + * short of actually crashing the machine we're running on by filling some + * kernel table. Secondly, it keeps the size of the scoreboard file small + * enough that we can read the whole thing without worrying too much about + * the overhead. + */ +#ifndef DEFAULT_SERVER_LIMIT +#define DEFAULT_SERVER_LIMIT 16 +#endif + +/* Admin can't tune ServerLimit beyond MAX_SERVER_LIMIT. We want + * some sort of compile-time limit to help catch typos. + */ +#ifndef MAX_SERVER_LIMIT +#define MAX_SERVER_LIMIT 20000 +#endif + +/* Limit on the threads per process. Clients will be locked out if more than + * this 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 + +#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 active_daemons = 0; /* workers that still active, i.e. are + not shutting down gracefully */ +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; +}; + +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. + * 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 *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 q_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 overall queues' next expiry according to the + * first entry of this queue (oldest), if necessary. + */ + el = APR_RING_FIRST(&q->head); + q_expiry = el->queue_timestamp + q->timeout; + next_expiry = queues_next_expiry; + if (!next_expiry || next_expiry > q_expiry + TIMEOUT_FUDGE_FACTOR) { + queues_next_expiry = q_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) + +/* 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 +} poll_type_e; + +typedef struct +{ + poll_type_e type; + void *baton; +} listener_poll_type; + +/* 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; + + 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_daemons_limit; + + /* + * 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; + + /* + * 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; +#ifndef MAX_SPAWN_RATE +#define MAX_SPAWN_RATE (32) +#endif + int hold_off_on_exponential_spawning; +} event_retained_data; +static event_retained_data *retained; + +typedef struct event_child_bucket { + ap_pod_t *pod; + ap_listen_rec *listeners; +} event_child_bucket; +static event_child_bucket *all_buckets, /* All listeners buckets */ + *my_bucket; /* Current child bucket */ + +struct event_srv_cfg_s { + struct timeout_queue *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(void) +{ + 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; + } + } + return 1; +} + +static void abort_socket_nonblocking(apr_socket_t *csd) +{ + apr_status_t rv; + apr_socket_timeout_set(csd, 0); +#if defined(SOL_SOCKET) && defined(SO_LINGER) + /* This socket is over now, and we don't want to block nor linger + * anymore, so reset it. A normal close could still linger in the + * system, while RST is fast, nonblocking, and what the peer will + * get if it sends us further data anyway. + */ + { + apr_os_sock_t osd = -1; + struct linger opt; + opt.l_onoff = 1; + opt.l_linger = 0; /* zero timeout is RST */ + apr_os_sock_get(&osd, csd); + setsockopt(osd, SOL_SOCKET, SO_LINGER, (void *)&opt, sizeof opt); + } +#endif + 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); + } +} + +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; + abort_socket_nonblocking(csd); + } + } + for (;;) { + event_conn_state_t *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; + abort_socket_nonblocking(cs->pfd.desc.s); + } +} + +static void wakeup_listener(void) +{ + 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 */ + } +} + +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_daemons_limit; + 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_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; + default: + *rv = APR_ENOTIMPL; + break; + } + return OK; +} + +static void event_note_child_killed(int childnum, pid_t pid, ap_generation_t gen) +{ + if (childnum != -1) { /* child had a scoreboard slot? */ + ap_run_child_status(ap_server_conf, + ap_scoreboard_image->parent[childnum].pid, + ap_scoreboard_image->parent[childnum].generation, + childnum, MPM_CHILD_EXITED); + ap_scoreboard_image->parent[childnum].pid = 0; + } + 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; + 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); +} + +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 (pchild) { + apr_pool_destroy(pchild); + } + + if (one_process) { + event_note_child_killed(/* 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_; + switch (cs->pub.state) { + 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) + || (listeners_disabled() && !connections_above_limit()))) { + apr_pollset_wakeup(event_pollset); + } + 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); +} + +/* + * Close our side of the connection, flushing data to the client first. + * Pre-condition: cs is not in any timeout queue and not in the pollset, + * timeout_mutex is not locked + * return: 0 if connection is fully closed, + * 1 if connection is lingering + * May only be called by worker thread. + */ +static int start_lingering_close_blocking(event_conn_state_t *cs) +{ + apr_socket_t *csd = cs->pfd.desc.s; + + if (ap_start_lingering_close(cs->c)) { + notify_suspend(cs); + apr_socket_close(csd); + ap_queue_info_push_pool(worker_queue_info, cs->p); + return DONE; + } + +#ifdef AP_DEBUG + { + apr_status_t rv; + rv = apr_socket_timeout_set(csd, 0); + AP_DEBUG_ASSERT(rv == APR_SUCCESS); + } +#else + apr_socket_timeout_set(csd, 0); +#endif + + cs->queue_timestamp = apr_time_now(); + /* + * 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; + } + apr_atomic_inc32(&lingering_count); + notify_suspend(cs); + + return OK; +} + +/* + * 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: cs is not in any timeout queue and not in the pollset, + * timeout_mutex is not locked + * return: 1 connection is alive (but aside and about to linger) + * May be called by listener thread. + */ +static int start_lingering_close_nonblocking(event_conn_state_t *cs) +{ + event_conn_state_t *chain; + for (;;) { + cs->chain = chain = defer_linger_chain; + if (apr_atomic_casptr((void *)&defer_linger_chain, cs, + chain) != chain) { + /* Race lost, try again */ + continue; + } + return 1; + } +} + +/* + * forcibly close a lingering connection after the lingering period has + * expired + * Pre-condition: cs is not in any timeout queue and not in the pollset + * return: irrelevant (need same prototype as start_lingering_close) + */ +static int stop_lingering_close(event_conn_state_t *cs) +{ + apr_socket_t *csd = ap_get_conn_socket(cs->c); + ap_log_error(APLOG_MARK, APLOG_TRACE4, 0, ap_server_conf, + "socket abort in state %i", (int)cs->pub.state); + abort_socket_nonblocking(csd); + ap_queue_info_push_pool(worker_queue_info, cs->p); + if (dying) + ap_queue_interrupt_one(worker_queue); + return 0; +} + +/* + * 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); + +/* + * 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; + 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; + cs->c = c; + c->cs = &(cs->pub); + 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.reqevents = APR_POLLIN; + 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_run_pre_connection(c, sock); + if (rc != OK && rc != DONE) { + ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, APLOGNO(00469) + "process_socket: connection aborted"); + c->aborted = 1; + } + + /** + * 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_CHECK_REQUEST_LINE_READABLE + * + * 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_READ_REQUEST_LINE; + + cs->pub.sense = CONN_SENSE_DEFAULT; + rc = OK; + } + 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 (c->aborted) { + /* do lingering close below */ + cs->pub.state = CONN_STATE_LINGER; + } + else if (cs->pub.state >= CONN_STATE_LINGER) { + /* fall through */ + } + else { + if (cs->pub.state == CONN_STATE_READ_REQUEST_LINE + /* 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) { +read_request: + 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); + } + if (cs->pub.state > CONN_STATE_LINGER) { + cs->pub.state = CONN_STATE_LINGER; + } + if (rc == DONE) { + rc = OK; + } + } + } + /* + * The process_connection hooks above should set the connection state + * appropriately upon return, for event MPM to either: + * - do lingering close (CONN_STATE_LINGER), + * - wait for readability of the next request with respect to the keepalive + * timeout (state CONN_STATE_CHECK_REQUEST_LINE_READABLE), + * - wait for read/write-ability of the underlying socket with respect to + * its timeout by setting c->clogging_input_filters to 1 and the sense + * to CONN_SENSE_WANT_READ/WRITE (state CONN_STATE_WRITE_COMPLETION), + * - keep flushing the output filters stack in nonblocking mode, and then + * if required wait for read/write-ability of the underlying socket with + * respect to its own timeout (state CONN_STATE_WRITE_COMPLETION); since + * completion at some point may require reads (e.g. SSL_ERROR_WANT_READ), + * an output filter can also set the sense to CONN_SENSE_WANT_READ at any + * time for event MPM to do the right thing, + * - suspend the connection (SUSPENDED) such that it now interracts with + * the MPM through suspend/resume_connection() hooks, and/or registered + * poll callbacks (PT_USER), and/or registered timed callbacks triggered + * by timer events. + * If a process_connection hook returns an error or no hook sets the state + * to one of the above expected value, we 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_READ_REQUEST_LINE 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. + */ + if (rc != OK || (cs->pub.state >= CONN_STATE_NUM) + || (cs->pub.state < CONN_STATE_LINGER + && cs->pub.state != CONN_STATE_WRITE_COMPLETION + && cs->pub.state != CONN_STATE_CHECK_REQUEST_LINE_READABLE + && cs->pub.state != CONN_STATE_SUSPENDED)) { + ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, APLOGNO(10111) + "process_socket: connection processing %s: closing", + rc ? apr_psprintf(c->pool, "returned error %i", rc) + : apr_psprintf(c->pool, "unexpected state %i", + (int)cs->pub.state)); + cs->pub.state = CONN_STATE_LINGER; + } + + if (cs->pub.state == CONN_STATE_WRITE_COMPLETION) { + ap_filter_t *output_filter = c->output_filters; + apr_status_t rv; + ap_update_child_status(cs->sbh, SERVER_BUSY_WRITE, NULL); + while (output_filter->next != NULL) { + output_filter = output_filter->next; + } + rv = output_filter->frec->filter_func.out_func(output_filter, NULL); + if (rv != APR_SUCCESS) { + ap_log_cerror(APLOG_MARK, APLOG_DEBUG, rv, c, APLOGNO(00470) + "network write failure in core output filter"); + cs->pub.state = CONN_STATE_LINGER; + } + else if (c->data_in_output_filters) { + /* Still in WRITE_COMPLETION_STATE: + * Set a write timeout for this connection, and let the + * event thread poll for writeability. + */ + cs->queue_timestamp = apr_time_now(); + notify_suspend(cs); + + if (cs->pub.sense == CONN_SENSE_WANT_READ) { + cs->pfd.reqevents = APR_POLLIN; + } + else { + cs->pfd.reqevents = APR_POLLOUT; + } + /* POLLHUP/ERR are usually returned event only (ignored here), but + * some pollset backends may require them in reqevents to do the + * right thing, so it shouldn't hurt. + */ + cs->pfd.reqevents |= APR_POLLHUP | APR_POLLERR; + cs->pub.sense = CONN_SENSE_DEFAULT; + + 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 for " + "write completion"); + apr_socket_close(cs->pfd.desc.s); + ap_queue_info_push_pool(worker_queue_info, cs->p); + } + else { + apr_thread_mutex_unlock(timeout_mutex); + } + return; + } + else if (c->keepalive != AP_CONN_KEEPALIVE || c->aborted || + listener_may_exit) { + cs->pub.state = CONN_STATE_LINGER; + } + else if (c->data_in_input_filters) { + cs->pub.state = CONN_STATE_READ_REQUEST_LINE; + goto read_request; + } + else { + cs->pub.state = CONN_STATE_CHECK_REQUEST_LINE_READABLE; + } + } + + if (cs->pub.state == CONN_STATE_CHECK_REQUEST_LINE_READABLE) { + 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->pfd.reqevents = APR_POLLIN; + 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"); + apr_socket_close(cs->pfd.desc.s); + ap_queue_info_push_pool(worker_queue_info, cs->p); + } + else { + apr_thread_mutex_unlock(timeout_mutex); + } + return; + } + + if (cs->pub.state == CONN_STATE_SUSPENDED) { + apr_atomic_inc32(&suspended_count); + notify_suspend(cs); + return; + } + + if (cs->pub.state == CONN_STATE_LINGER) { + rc = start_lingering_close_blocking(cs); + } + if (rc == OK && (cs->pub.state == CONN_STATE_LINGER_NORMAL || + cs->pub.state == CONN_STATE_LINGER_SHORT)) { + process_lingering_close(cs); + } +} + +/* 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); + } + else { + /* keep going */ + conns_this_child = APR_INT32_MAX; + } +} + +static void close_listeners(int *closed) +{ + if (!*closed) { + int i; + ap_close_listeners_ex(my_bucket->listeners); + *closed = 1; + 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); + } +} + +static void unblock_signal(int sig) +{ + sigset_t sig_mask; + + sigemptyset(&sig_mask); + sigaddset(&sig_mask, sig); +#if defined(SIGPROCMASK_SETS_THREAD_MASK) + sigprocmask(SIG_UNBLOCK, &sig_mask, NULL); +#else + pthread_sigmask(SIG_UNBLOCK, &sig_mask, NULL); +#endif +} + +static void dummy_signal_handler(int sig) +{ + /* XXX If specifying SIG_IGN is guaranteed to unblock a syscall, + * then we don't need this goofy function. + */ +} + + +static 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 (csd) { + abort_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 APR_RING_HEAD(timer_free_ring_t, 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 apr_status_t event_register_timed_callback(apr_time_t t, + ap_mpm_callback_fn_t *cbfn, + void *baton) +{ + timer_event_t *te; + /* oh yeah, and make locking smarter/fine grained. */ + apr_thread_mutex_lock(g_timer_skiplist_mtx); + + if (!APR_RING_EMPTY(&timer_free_ring, timer_event_t, link)) { + te = APR_RING_FIRST(&timer_free_ring); + 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; + /* XXXXX: optimize */ + te->when = t + apr_time_now(); + + { + apr_time_t next_expiry; + + /* Okay, add sorted by when.. */ + apr_skiplist_insert(timer_skiplist, te); + + /* Cheaply update the overall timers' next expiry according to + * this event, if necessary. + */ + 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 APR_SUCCESS; +} + + +/* + * Close socket and clean up if remote closed its end while we were in + * lingering close. 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. + */ +#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; + + /* socket is already in non-blocking state */ + do { + nbytes = sizeof(dummybuf); + rv = apr_socket_recv(csd, dummybuf, &nbytes); + } while (rv == APR_SUCCESS); + + if (!APR_STATUS_IS_EAGAIN(rv)) { + rv = apr_socket_close(csd); + AP_DEBUG_ASSERT(rv == APR_SUCCESS); + ap_queue_info_push_pool(worker_queue_info, cs->p); + return; + } + + /* Re-queue the connection to come back when readable */ + cs->pfd.reqevents = APR_POLLIN; + cs->pub.sense = CONN_SENSE_DEFAULT; + 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"); + rv = apr_socket_close(cs->pfd.desc.s); + AP_DEBUG_ASSERT(rv == APR_SUCCESS); + ap_queue_info_push_pool(worker_queue_info, cs->p); + return; + } + apr_thread_mutex_unlock(timeout_mutex); +} + +/* call 'func' for all elements of 'q' with timeout less than 'timeout_time'. + * 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 timeout_time, + int (*func)(event_conn_state_t *)) +{ + apr_uint32_t total = 0, count; + event_conn_state_t *first, *cs, *last; + struct timeout_head_t trash; + struct timeout_queue *qp; + apr_status_t rv; + + if (!*q->total) { + return; + } + + APR_RING_INIT(&trash, 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 timeout_time was given (asked for 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 timeout_time (~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 (timeout_time + && cs->queue_timestamp + qp->timeout > timeout_time + && cs->queue_timestamp < timeout_time + qp->timeout) { + /* Since this is the next expiring of this queue, update the + * overall queues' next expiry if it's later than this one. + */ + apr_time_t q_expiry = cs->queue_timestamp + qp->timeout; + apr_time_t next_expiry = queues_next_expiry; + if (!next_expiry || next_expiry > q_expiry) { + queues_next_expiry = q_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, 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); + 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 timeout_time) +{ + /* If all workers are busy, we kill older keep-alive connections so + * that they may connect to another process. + */ + if (!timeout_time) { + ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf, + "All workers are busy or dying, will close %u " + "keep-alive connections", *keepalive_q->total); + } + process_timeout_queue(keepalive_q, timeout_time, + start_lingering_close_nonblocking); +} + +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); + + /* Unblock the signal used to wake this thread up, and set a handler for + * it. + */ + unblock_signal(LISTENER_SIGNAL); + apr_signal(LISTENER_SIGNAL, dummy_signal_handler); + + for (;;) { + timer_event_t *te; + const apr_pollfd_t *out_pfd; + apr_int32_t num = 0; + apr_interval_time_t timeout_interval; + apr_time_t now, timeout_time; + int workers_were_busy = 0; + + if (conns_this_child <= 0) + check_infinite_requests(); + + if (listener_may_exit) { + close_listeners(&closed); + if (terminate_mode == ST_UNGRACEFUL + || apr_atomic_read32(&connection_count) == 0) + break; + } + + now = apr_time_now(); + if (APLOGtrace6(ap_server_conf)) { + /* trace log status every second */ + if (now - last_log > apr_time_from_sec(1)) { + last_log = now; + apr_thread_mutex_lock(timeout_mutex); + ap_log_error(APLOG_MARK, APLOG_TRACE6, 0, ap_server_conf, + "connections: %u (clogged: %u write-completion: %d " + "keep-alive: %d lingering: %d suspended: %u)", + apr_atomic_read32(&connection_count), + apr_atomic_read32(&clogged_count), + *(volatile apr_uint32_t*)write_completion_q->total, + *(volatile apr_uint32_t*)keepalive_q->total, + apr_atomic_read32(&lingering_count), + apr_atomic_read32(&suspended_count)); + if (dying) { + ap_log_error(APLOG_MARK, APLOG_TRACE6, 0, ap_server_conf, + "%u/%u workers shutdown", + apr_atomic_read32(&threads_shutdown), + threads_per_child); + } + apr_thread_mutex_unlock(timeout_mutex); + } + } + + /* 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. + */ + timeout_interval = -1; + + /* Push expired timers to a worker, the first remaining one determines + * the maximum time to poll() below, if any. + */ + timeout_time = timers_next_expiry; + if (timeout_time && timeout_time < now + EVENT_FUDGE_FACTOR) { + apr_thread_mutex_lock(g_timer_skiplist_mtx); + while ((te = apr_skiplist_peek(timer_skiplist))) { + if (te->when > now + EVENT_FUDGE_FACTOR) { + timers_next_expiry = te->when; + timeout_interval = te->when - now; + break; + } + apr_skiplist_pop(timer_skiplist, NULL); + push_timer2worker(te); + } + if (!te) { + timers_next_expiry = 0; + } + apr_thread_mutex_unlock(g_timer_skiplist_mtx); + } + + /* Same for queues, use their next expiry, if any. */ + timeout_time = queues_next_expiry; + if (timeout_time + && (timeout_interval < 0 + || timeout_time <= now + || timeout_interval > timeout_time - now)) { + timeout_interval = timeout_time > now ? timeout_time - now : 1; + } + + /* 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_interval < 0 + || timeout_interval > NON_WAKEABLE_POLL_TIMEOUT)) { + timeout_interval = NON_WAKEABLE_POLL_TIMEOUT; + } + + rc = apr_pollset_poll(event_pollset, timeout_interval, &num, &out_pfd); + if (rc != APR_SUCCESS) { + if (APR_STATUS_IS_EINTR(rc)) { + /* Woken up, if we are exiting or listeners are disabled we + * must fall through to kill kept-alive connections or test + * whether listeners should be re-enabled. Otherwise we only + * need to update timeouts (logic is above, so simply restart + * the loop). + */ + if (!listener_may_exit && !listeners_disabled()) { + continue; + } + timeout_time = 0; + } + else if (!APR_STATUS_IS_TIMEUP(rc)) { + ap_log_error(APLOG_MARK, APLOG_CRIT, rc, ap_server_conf, + "apr_pollset_poll failed. Attempting to " + "shutdown process gracefully"); + signal_threads(ST_GRACEFUL); + } + num = 0; + } + + if (listener_may_exit) { + close_listeners(&closed); + if (terminate_mode == ST_UNGRACEFUL + || apr_atomic_read32(&connection_count) == 0) + break; + } + + for (; 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_CHECK_REQUEST_LINE_READABLE: + cs->pub.state = CONN_STATE_READ_REQUEST_LINE; + 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"); + start_lingering_close_nonblocking(cs); + 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 reset so the choice is to favor + * incoming/alive connections. + */ + get_worker(&have_idle_worker, blocking, + &workers_were_busy); + if (!have_idle_worker) { + if (remove_from_q == cs->sc->ka_q) { + start_lingering_close_nonblocking(cs); + } + else { + stop_lingering_close(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, + "All workers busy, not accepting new conns " + "in this process"); + } + else if (connections_above_limit()) { + disable_listensocks(); + ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, + "Too many open connections (%u), " + "not accepting new conns in this process", + apr_atomic_read32(&connection_count)); + ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf, + "Idle workers: %u", + ap_queue_info_num_idlers(worker_queue_info)); + workers_were_busy = 1; + } + 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); + } + + 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 */ + } /* for processing poll */ + + /* XXX possible optimization: stash the current time for use as + * r->request_time for new requests + */ + /* We process the timeout queues here only when their overall next + * expiry (read once above) is over. 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. + */ + if (timeout_time && timeout_time < (now = apr_time_now())) { + timeout_time = now + TIMEOUT_FUDGE_FACTOR; + + /* handle timed out sockets */ + apr_thread_mutex_lock(timeout_mutex); + + /* Processing all the queues below will recompute this. */ + queues_next_expiry = 0; + + /* Step 1: keepalive timeouts */ + if (workers_were_busy || dying) { + process_keepalive_queue(0); /* kill'em all \m/ */ + } + else { + process_keepalive_queue(timeout_time); + } + /* Step 2: write completion timeouts */ + process_timeout_queue(write_completion_q, timeout_time, + start_lingering_close_nonblocking); + /* Step 3: (normal) lingering close completion timeouts */ + process_timeout_queue(linger_q, timeout_time, + stop_lingering_close); + /* Step 4: (short) lingering close completion timeouts */ + process_timeout_queue(short_linger_q, timeout_time, + stop_lingering_close); + + apr_thread_mutex_unlock(timeout_mutex); + + ps->keep_alive = *(volatile apr_uint32_t*)keepalive_q->total; + ps->write_completion = *(volatile apr_uint32_t*)write_completion_q->total; + ps->connections = apr_atomic_read32(&connection_count); + ps->suspended = apr_atomic_read32(&suspended_count); + ps->lingering_close = apr_atomic_read32(&lingering_count); + } + else if ((workers_were_busy || dying) + && *(volatile apr_uint32_t*)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 (listeners_disabled() + && !workers_were_busy + && !connections_above_limit()) { + enable_listensocks(); + } + } /* listener main loop */ + + close_listeners(&closed); + 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); + + while (!workers_may_exit) { + 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, + "ap_queue_info_set_idle failed. Attempting to " + "shutdown process gracefully."); + signal_threads(ST_GRACEFUL); + break; + } + is_idle = 1; + } + + ap_update_child_status_from_indexes(process_slot, thread_slot, + 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, 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; + + worker_sockets[thread_slot] = csd = cs->pfd.desc.s; +#ifdef AP_DEBUG + rv = apr_socket_timeout_set(csd, SECONDS_TO_LINGER); + AP_DEBUG_ASSERT(rv == APR_SUCCESS); +#else + apr_socket_timeout_set(csd, SECONDS_TO_LINGER); +#endif + cs->pub.state = CONN_STATE_LINGER; + 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 = apr_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) + "apr_thread_create: unable to create listener thread"); + /* let the parent decide how bad this really is */ + clean_child_exit(APEXIT_CHILDSICK); + } + apr_os_thread_get(&listener_os_thread, ts->listener); +} + +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, 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 explicitely + * 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 */ + pollset_flags = APR_POLLSET_THREADSAFE | APR_POLLSET_NOCOPY | + APR_POLLSET_NODEFAULT | APR_POLLSET_WAKEABLE; + for (i = 0; i < sizeof(good_methods) / sizeof(good_methods[0]); i++) { + rv = apr_pollset_create_ex(&event_pollset, pollset_size, pruntime, + pollset_flags, good_methods[i]); + if (rv == APR_SUCCESS) { + listener_is_wakeable = 1; + break; + } + } + if (rv != APR_SUCCESS) { + pollset_flags &= ~APR_POLLSET_WAKEABLE; + for (i = 0; i < sizeof(good_methods) / sizeof(good_methods[0]); i++) { + rv = apr_pollset_create_ex(&event_pollset, pollset_size, pruntime, + pollset_flags, good_methods[i]); + if (rv == APR_SUCCESS) { + break; + } + } + } + if (rv != APR_SUCCESS) { + pollset_flags &= ~APR_POLLSET_NODEFAULT; + 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; + 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 = apr_thread_create(&threads[i], thread_attr, + worker_thread, my_info, pruntime); + if (rv != APR_SUCCESS) { + ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, + APLOGNO(03104) + "apr_thread_create: unable to create worker thread"); + /* let the parent decide how bad this really is */ + clean_child_exit(APEXIT_CHILDSICK); + } + threads_created++; + } + + /* Start the listener only when there are workers available */ + if (!listener_started && threads_created) { + create_listener_thread(ts); + listener_started = 1; + } + + + if (start_thread_may_exit || threads_created == threads_per_child) { + break; + } + /* wait for previous generation to clean up an entry */ + apr_sleep(apr_time_from_sec(1)); + ++loops; + if (loops % 120 == 0) { /* every couple of minutes */ + if (prev_threads_created == threads_created) { + ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, + "child %" APR_PID_T_FMT " isn't taking over " + "slots very quickly (%d of %d)", + ap_my_pid, threads_created, + threads_per_child); + } + prev_threads_created = threads_created; + } + } + + /* What state should this child_main process be listed as in the + * scoreboard...? + * ap_update_child_status_from_indexes(my_child_num, i, SERVER_STARTING, + * (request_rec *) NULL); + * + * This state should be listed separately in the scoreboard, in some kind + * of process_status, not mixed in with the worker threads' status. + * "life_status" is almost right, but it's in the worker's structure, and + * the name could be clearer. gla + */ + apr_thread_exit(thd, APR_SUCCESS); + return NULL; +} + +static void join_workers(apr_thread_t * listener, apr_thread_t ** threads) +{ + int i; + apr_status_t rv, thread_rv; + + if (listener) { + int iter; + + /* deal with a rare timing window which affects waking up the + * listener thread... if the signal sent to the listener thread + * is delivered between the time it verifies that the + * listener_may_exit flag is clear and the time it enters a + * blocking syscall, the signal didn't do any good... work around + * that by sleeping briefly and sending it again + */ + + iter = 0; + while (iter < 10 && !dying) { + /* listener has not stopped accepting yet */ + apr_sleep(apr_time_make(0, 500000)); + wakeup_listener(); + ++iter; + } + if (iter >= 10) { + ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, 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"); + + /* close unused listeners and pods */ + for (i = 0; i < retained->mpm->num_buckets; i++) { + if (i != child_bucket) { + ap_close_listeners_ex(all_buckets[i].listeners); + ap_mpm_podx_close(all_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" (implicitely) 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); + } + + 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 = apr_thread_create(&start_thread_id, thread_attr, start_threads, + ts, pchild); + if (rv != APR_SUCCESS) { + ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(00480) + "apr_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 + */ + unblock_signal(SIGTERM); + apr_signal(SIGTERM, dummy_signal_handler); + /* 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). + */ + join_workers(ts->listener, threads); + } + + free(threads); + + clean_child_exit(resource_shortage ? APEXIT_CHILDSICK : 0); +} + +static int make_child(server_rec * s, int slot, int bucket) +{ + int pid; + + if (slot + 1 > retained->max_daemons_limit) { + retained->max_daemons_limit = 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 = &all_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) { + my_bucket = &all_buckets[bucket]; + +#ifdef HAVE_BINDPROCESSOR + /* By default, AIX binds to a single processor. This bit unbinds + * children which will then bind to another CPU. + */ + int status = bindprocessor(BINDPROCESS, (int) getpid(), + PROCESSOR_CLASS_ANY); + if (status != OK) + ap_log_error(APLOG_MARK, APLOG_DEBUG, errno, + ap_server_conf, APLOGNO(00482) + "processor unbind failed"); +#endif + RAISE_SIGSTOP(MAKE_CHILD); + + apr_signal(SIGTERM, just_die); + child_main(slot, bucket); + /* NOTREACHED */ + ap_assert(0); + return -1; + } + + ap_scoreboard_image->parent[slot].quiescing = 0; + ap_scoreboard_image->parent[slot].not_accepting = 0; + ap_scoreboard_image->parent[slot].bucket = bucket; + event_note_child_started(slot, pid); + active_daemons++; + retained->total_daemons++; + 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 num_buckets) +{ + int i, j; + int idle_thread_count = 0; + worker_score *ws; + process_score *ps; + int free_length = 0; + int free_slots[MAX_SPAWN_RATE]; + int last_non_dead = -1; + int active_thread_count = 0; + + for (i = 0; i < server_limit; ++i) { + /* Initialization to satisfy the compiler. It doesn't know + * that threads_per_child is always > 0 */ + int status = SERVER_DEAD; + int child_threads_active = 0; + + if (i >= retained->max_daemons_limit && + 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) { + for (j = 0; j < threads_per_child; j++) { + ws = &ap_scoreboard_image->servers[i][j]; + status = ws->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 + && ps->bucket == child_bucket) + { + ++idle_thread_count; + } + if (status >= SERVER_READY && status < SERVER_GRACEFUL) { + ++child_threads_active; + } + } + last_non_dead = i; + } + active_thread_count += child_threads_active; + if (!ps->pid && free_length < retained->idle_spawn_rate[child_bucket]) + free_slots[free_length++] = i; + else if (child_threads_active == threads_per_child) + had_healthy_child = 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 { + /* 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; + } + } + + retained->max_daemons_limit = last_non_dead + 1; + + 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 when the total number of processes + * is high. + * + * 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 + */ + if (retained->total_daemons <= active_daemons_limit && + retained->total_daemons < server_limit) { + /* Kill off one child */ + ap_mpm_podx_signal(all_buckets[child_bucket].pod, + AP_MPM_PODX_GRACEFUL); + retained->idle_spawn_rate[child_bucket] = 1; + active_daemons--; + } else { + ap_log_error(APLOG_MARK, APLOG_TRACE5, 0, ap_server_conf, + "Not shutting down child: total daemons %d / " + "active limit %d / ServerLimit %d", + retained->total_daemons, active_daemons_limit, + server_limit); + } + } + else if (idle_thread_count < min_spare_threads / num_buckets) { + if (active_thread_count >= max_workers) { + 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 (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, active_daemons, + retained->total_daemons); + } + for (i = 0; i < free_length; ++i) { + ap_log_error(APLOG_MARK, APLOG_TRACE5, 0, ap_server_conf, + "Spawning new child: slot %d active / " + "total daemons: %d/%d", + free_slots[i], active_daemons, + retained->total_daemons); + make_child(ap_server_conf, free_slots[i], child_bucket); + } + /* 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 / num_buckets) { + retained->idle_spawn_rate[child_bucket] *= 2; + } + } + } + else { + retained->idle_spawn_rate[child_bucket] = 1; + } +} + +static void server_main_loop(int remaining_children_to_start, int num_buckets) +{ + 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) { + process_score *ps; + + for (i = 0; i < threads_per_child; i++) + ap_update_child_status_from_indexes(child_slot, i, + SERVER_DEAD, NULL); + + event_note_child_killed(child_slot, 0, 0); + ps = &ap_scoreboard_image->parent[child_slot]; + if (!ps->quiescing) + active_daemons--; + ps->quiescing = 0; + /* NOTE: We don't dec in the (child_slot < 0) case! */ + retained->total_daemons--; + if (processed_status == APEXIT_CHILDSICK) { + /* resource shortage, minimize the fork rate */ + retained->idle_spawn_rate[ps->bucket] = 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, ps->bucket); + --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. + */ + continue; + } + else if (remaining_children_to_start) { + /* we hit a 1 second timeout in which none of the previous + * generation of children needed to be reaped... so assume + * they're all done, and pick up the slack if any is left. + */ + startup_children(remaining_children_to_start); + remaining_children_to_start = 0; + /* In any event we really shouldn't do the code below because + * few of the servers we just started are in the IDLE state + * yet, so we'd mistakenly create an extra server. + */ + continue; + } + + for (i = 0; i < num_buckets; i++) { + perform_idle_server_maintenance(i, num_buckets); + } + } +} + +static int event_run(apr_pool_t * _pconf, apr_pool_t * plog, server_rec * s) +{ + int num_buckets = retained->mpm->num_buckets; + int remaining_children_to_start; + int i; + + ap_log_pid(pconf, ap_pid_fname); + + if (!retained->mpm->was_graceful) { + if (ap_run_pre_mpm(s->process->pool, SB_SHARED) != OK) { + retained->mpm->mpm_state = AP_MPMQ_STOPPING; + return !OK; + } + /* fix the generation number in the global score; we just got a new, + * cleared scoreboard + */ + ap_scoreboard_image->global->running_generation = retained->mpm->my_generation; + } + + ap_unixd_mpm_set_signals(pconf, one_process); + + /* 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; + + /* 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, num_buckets); + 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(all_buckets[i].pod, active_daemons_limit, + AP_MPM_PODX_RESTART); + } + ap_reclaim_child_processes(1, /* Start with SIGTERM */ + event_note_child_killed); + + 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(all_buckets[i].pod, active_daemons_limit, + AP_MPM_PODX_GRACEFUL); + } + ap_relieve_child_processes(event_note_child_killed); + + 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_killed); + + active_children = 0; + for (index = 0; index < retained->max_daemons_limit; ++index) { + if (ap_mpm_safe_kill(MPM_CHILD_PID(index), 0) == APR_SUCCESS) { + active_children = 1; + /* Having just one child is enough to stay around */ + break; + } + } + } while (!retained->mpm->shutdown_pending && active_children && + (!ap_graceful_shutdown_timeout || apr_time_now() < cutoff)); + + /* We might be here because we received SIGTERM, either + * way, try and make sure that all of our processes are + * really dead. + */ + for (i = 0; i < num_buckets; i++) { + ap_mpm_podx_killpg(all_buckets[i].pod, active_daemons_limit, + AP_MPM_PODX_RESTART); + } + ap_reclaim_child_processes(1, event_note_child_killed); + + return DONE; + } + + /* we've been told to restart */ + if (one_process) { + /* not worth thinking about */ + return DONE; + } + + /* advance to the next generation */ + /* XXX: we really need to make sure this new generation number isn't in + * use by any of the children. + */ + ++retained->mpm->my_generation; + ap_scoreboard_image->global->running_generation = retained->mpm->my_generation; + + if (!retained->mpm->is_ungraceful) { + ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00493) + AP_SIG_GRACEFUL_STRING + " received. Doing graceful restart"); + /* wake up the children...time to die. But we'll have more soon */ + for (i = 0; i < num_buckets; i++) { + ap_mpm_podx_killpg(all_buckets[i].pod, active_daemons_limit, + AP_MPM_PODX_GRACEFUL); + } + + /* This is mostly for debugging... so that we know what is still + * gracefully dealing with existing request. + */ + + } + else { + /* Kill 'em all. Since the child acts the same on the parents SIGTERM + * and a SIGHUP, we may as well use the same signal, because some user + * pthreads are stealing signals from us left and right. + */ + for (i = 0; i < num_buckets; i++) { + ap_mpm_podx_killpg(all_buckets[i].pod, active_daemons_limit, + AP_MPM_PODX_RESTART); + } + + ap_reclaim_child_processes(1, /* Start with SIGTERM */ + event_note_child_killed); + ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00494) + "SIGHUP received. Attempting to restart"); + } + + active_daemons = 0; + + 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_READ_REQUEST_LINE; + 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; + int num_buckets = 0; + ap_listen_rec **listen_buckets; + apr_status_t rv; + int i; + + pconf = p; + + /* the reverse of pre_config, we want this only the first time around */ + if (retained->mpm->module_loads == 1) { + startup = 1; + level_flags |= APLOG_STARTUP; + } + + if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) { + ap_log_error(APLOG_MARK, APLOG_ALERT | level_flags, 0, + (startup ? NULL : s), + "no listening sockets available, shutting down"); + return !OK; + } + + if (one_process) { + num_buckets = 1; + } + else if (retained->mpm->was_graceful) { + /* Preserve the number of buckets on graceful restarts. */ + num_buckets = retained->mpm->num_buckets; + } + if ((rv = ap_duplicate_listeners(pconf, ap_server_conf, + &listen_buckets, &num_buckets))) { + ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv, + (startup ? NULL : s), + "could not duplicate listeners"); + return !OK; + } + + all_buckets = apr_pcalloc(pconf, num_buckets * sizeof(*all_buckets)); + for (i = 0; i < num_buckets; i++) { + if (!one_process && /* no POD in one_process mode */ + (rv = ap_mpm_podx_open(pconf, &all_buckets[i].pod))) { + ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv, + (startup ? NULL : s), + "could not open pipe-of-death"); + return !OK; + } + all_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)); + 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; + + /* for skiplist */ + srand((unsigned int)apr_time_now()); + 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->max_daemons_limit = -1; + if (retained->mpm->module_loads) { + test_atomics = 1; + } + } + retained->mpm->mpm_state = AP_MPMQ_STARTING; + if (retained->mpm->baton != retained) { + retained->mpm->was_graceful = 0; + retained->mpm->baton = retained; + } + ++retained->mpm->module_loads; + + /* 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; + + 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; + } wc, ka; + + /* Not needed in pre_config stage */ + if (ap_state_query(AP_SQ_MAIN_STATE) == AP_SQ_MS_CREATE_PRE_CONFIG) { + return OK; + } + + wc.tail = ka.tail = NULL; + wc.hash = apr_hash_make(ptemp); + ka.hash = apr_hash_make(ptemp); + + 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 (!wc.tail) { + /* The main server uses the global queues */ + 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 */ + 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->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_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_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_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 */ +}; |