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apache / httpd / 2a7de1e2a37464d166c1c8c5c41d7c4e49181c8c / . / server / mpm / event / event.c
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/* 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 "util_time.h"
#include <signal.h>
#include <limits.h> /* for INT_MAX */
#if HAVE_SERF
#include "mod_serf.h"
#include "serf.h"
#endif
/* Limit on the total --- clients will be locked out if more servers than
* this are needed. It is intended solely to keep the server from crashing
* when things get out of hand.
*
* We keep a hard maximum number of servers, for two reasons --- first off,
* in case something goes seriously wrong, we want to stop the fork bomb
* short of actually crashing the machine we're running on by filling some
* kernel table. Secondly, it keeps the size of the scoreboard file small
* enough that we can read the whole thing without worrying too much about
* the overhead.
*/
#ifndef DEFAULT_SERVER_LIMIT
#define DEFAULT_SERVER_LIMIT 16
#endif
/* Admin can't tune ServerLimit beyond MAX_SERVER_LIMIT. We want
* some sort of compile-time limit to help catch typos.
*/
#ifndef MAX_SERVER_LIMIT
#define MAX_SERVER_LIMIT 20000
#endif
/* Limit on the threads per process. Clients will be locked out if more than
* this are needed.
*
* We keep this for one reason it keeps the size of the scoreboard file small
* enough that we can read the whole thing without worrying too much about
* the overhead.
*/
#ifndef DEFAULT_THREAD_LIMIT
#define DEFAULT_THREAD_LIMIT 64
#endif
/* Admin can't tune ThreadLimit beyond MAX_THREAD_LIMIT. We want
* some sort of compile-time limit to help catch typos.
*/
#ifndef MAX_THREAD_LIMIT
#define MAX_THREAD_LIMIT 100000
#endif
#define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid)
#if !APR_VERSION_AT_LEAST(1,4,0)
#define apr_time_from_msec(x) (x * 1000)
#endif
#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;
/** Is lingering close from defer_lingering_close()? */
int deferred_linger;
};
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 elem_expiry;
apr_time_t next_expiry;
APR_RING_INSERT_TAIL(&q->head, el, event_conn_state_t, timeout_list);
++*q->total;
++q->count;
/* Cheaply update the global queues_next_expiry with the one of the
* first entry of this queue (oldest) if it expires before.
*/
el = APR_RING_FIRST(&q->head);
elem_expiry = el->queue_timestamp + q->timeout;
next_expiry = queues_next_expiry;
if (!next_expiry || next_expiry > elem_expiry + TIMEOUT_FUDGE_FACTOR) {
queues_next_expiry = elem_expiry;
/* Unblock the poll()ing listener for it to update its timeout. */
if (listener_is_wakeable) {
apr_pollset_wakeup(event_pollset);
}
}
}
static void TO_QUEUE_REMOVE(struct timeout_queue *q, event_conn_state_t *el)
{
APR_RING_REMOVE(el, timeout_list);
APR_RING_ELEM_INIT(el, timeout_list);
--*q->total;
--q->count;
}
static struct timeout_queue *TO_QUEUE_MAKE(apr_pool_t *p, apr_time_t t,
struct timeout_queue *ref)
{
struct timeout_queue *q;
q = apr_pcalloc(p, sizeof *q);
APR_RING_INIT(&q->head, event_conn_state_t, timeout_list);
q->total = (ref) ? ref->total : apr_pcalloc(p, sizeof *q->total);
q->timeout = t;
return q;
}
#define TO_QUEUE_ELEM_INIT(el) \
APR_RING_ELEM_INIT((el), timeout_list)
#if HAVE_SERF
typedef struct {
apr_pollset_t *pollset;
apr_pool_t *pool;
} s_baton_t;
static serf_context_t *g_serf;
#endif
/* The structure used to pass unique initialization info to each thread */
typedef struct
{
int pslot; /* process slot */
int tslot; /* worker slot of the thread */
} proc_info;
/* Structure used to pass information to the thread responsible for
* creating the rest of the threads.
*/
typedef struct
{
apr_thread_t **threads;
apr_thread_t *listener;
int child_num_arg;
apr_threadattr_t *threadattr;
} thread_starter;
typedef enum
{
PT_CSD,
PT_ACCEPT
#if HAVE_SERF
, PT_SERF
#endif
, PT_USER
} poll_type_e;
typedef struct
{
poll_type_e type;
void *baton;
} listener_poll_type;
typedef struct socket_callback_baton
{
ap_mpm_callback_fn_t *cbfunc;
void *user_baton;
apr_array_header_t *pfds;
timer_event_t *cancel_event; /* If a timeout was requested, a pointer to the timer event */
struct socket_callback_baton *next;
unsigned int signaled :1;
} socket_callback_baton_t;
/* 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(int *busy)
{
apr_uint32_t i_count = ap_queue_info_num_idlers(worker_queue_info);
if (i_count > 0) {
apr_uint32_t c_count = apr_atomic_read32(&connection_count);
apr_uint32_t l_count = apr_atomic_read32(&lingering_count);
if (c_count <= l_count
/* Off by 'listeners_disabled()' to avoid flip flop */
|| c_count - l_count < (apr_uint32_t)threads_per_child +
(i_count - listeners_disabled()) *
(worker_factor / WORKER_FACTOR_SCALE)) {
return 0;
}
}
else if (busy) {
*busy = 1;
}
return 1;
}
static void close_socket_nonblocking_(apr_socket_t *csd,
const char *from, int line)
{
apr_status_t rv;
apr_os_sock_t fd = -1;
/* close_worker_sockets() may have closed it already */
rv = apr_os_sock_get(&fd, csd);
ap_log_error(APLOG_MARK, APLOG_TRACE8, 0, ap_server_conf,
"closing socket %i/%pp from %s:%i", (int)fd, csd, from, line);
if (rv == APR_SUCCESS && fd == -1) {
return;
}
apr_socket_timeout_set(csd, 0);
rv = apr_socket_close(csd);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(00468)
"error closing socket");
AP_DEBUG_ASSERT(0);
}
}
#define close_socket_nonblocking(csd) \
close_socket_nonblocking_(csd, __FUNCTION__, __LINE__)
static void close_worker_sockets(void)
{
int i;
for (i = 0; i < threads_per_child; i++) {
apr_socket_t *csd = worker_sockets[i];
if (csd) {
worker_sockets[i] = NULL;
close_socket_nonblocking(csd);
}
}
}
static void wakeup_listener(void)
{
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
"wake up listener%s", listener_may_exit ? " again" : "");
listener_may_exit = 1;
disable_listensocks();
/* Unblock the listener if it's poll()ing */
if (event_pollset && listener_is_wakeable) {
apr_pollset_wakeup(event_pollset);
}
/* unblock the listener if it's waiting for a worker */
if (worker_queue_info) {
ap_queue_info_term(worker_queue_info);
}
if (!listener_os_thread) {
/* XXX there is an obscure path that this doesn't handle perfectly:
* right after listener thread is created but before
* listener_os_thread is set, the first worker thread hits an
* error and starts graceful termination
*/
return;
}
/*
* we should just be able to "kill(ap_my_pid, LISTENER_SIGNAL)" on all
* platforms and wake up the listener thread since it is the only thread
* with SIGHUP unblocked, but that doesn't work on Linux
*/
#ifdef HAVE_PTHREAD_KILL
pthread_kill(*listener_os_thread, LISTENER_SIGNAL);
#else
kill(ap_my_pid, LISTENER_SIGNAL);
#endif
}
#define ST_INIT 0
#define ST_GRACEFUL 1
#define ST_UNGRACEFUL 2
static int terminate_mode = ST_INIT;
static void signal_threads(int mode)
{
if (terminate_mode >= mode) {
return;
}
terminate_mode = mode;
retained->mpm->mpm_state = AP_MPMQ_STOPPING;
/* in case we weren't called from the listener thread, wake up the
* listener thread
*/
wakeup_listener();
/* for ungraceful termination, let the workers exit now;
* for graceful termination, the listener thread will notify the
* workers to exit once it has stopped accepting new connections
*/
if (mode == ST_UNGRACEFUL) {
workers_may_exit = 1;
ap_queue_interrupt_all(worker_queue);
close_worker_sockets(); /* forcefully kill all current connections */
}
}
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_HAS_SERF:
*result = 1;
break;
case AP_MPMQ_HARD_LIMIT_DAEMONS:
*result = server_limit;
break;
case AP_MPMQ_HARD_LIMIT_THREADS:
*result = thread_limit;
break;
case AP_MPMQ_MAX_THREADS:
*result = threads_per_child;
break;
case AP_MPMQ_MIN_SPARE_DAEMONS:
*result = 0;
break;
case AP_MPMQ_MIN_SPARE_THREADS:
*result = min_spare_threads;
break;
case AP_MPMQ_MAX_SPARE_DAEMONS:
*result = 0;
break;
case AP_MPMQ_MAX_SPARE_THREADS:
*result = max_spare_threads;
break;
case AP_MPMQ_MAX_REQUESTS_DAEMON:
*result = ap_max_requests_per_child;
break;
case AP_MPMQ_MAX_DAEMONS:
*result = active_daemons_limit;
break;
case AP_MPMQ_MPM_STATE:
*result = retained->mpm->mpm_state;
break;
case AP_MPMQ_GENERATION:
*result = retained->mpm->my_generation;
break;
case AP_MPMQ_CAN_SUSPEND:
*result = 1;
break;
case AP_MPMQ_CAN_POLL:
*result = 1;
break;
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_;
ap_log_cerror(APLOG_MARK, APLOG_TRACE8, 0, cs->c,
"cleanup connection from state %i", (int)cs->pub.state);
switch (cs->pub.state) {
case CONN_STATE_LINGER:
case CONN_STATE_LINGER_NORMAL:
case CONN_STATE_LINGER_SHORT:
apr_atomic_dec32(&lingering_count);
break;
case CONN_STATE_SUSPENDED:
apr_atomic_dec32(&suspended_count);
break;
default:
break;
}
/* Unblock the listener if it's waiting for connection_count = 0,
* or if the listening sockets were disabled due to limits and can
* now accept new connections.
*/
is_last_connection = !apr_atomic_dec32(&connection_count);
if (listener_is_wakeable
&& ((is_last_connection && listener_may_exit)
|| (listeners_disabled() && !connections_above_limit(NULL)))) {
apr_pollset_wakeup(event_pollset);
}
if (dying) {
/* Help worker_thread_should_exit_early() */
ap_queue_interrupt_one(worker_queue);
}
return APR_SUCCESS;
}
static void notify_suspend(event_conn_state_t *cs)
{
ap_run_suspend_connection(cs->c, cs->r);
cs->c->sbh = NULL;
cs->suspended = 1;
}
static void notify_resume(event_conn_state_t *cs, int cleanup)
{
cs->suspended = 0;
cs->c->sbh = cleanup ? NULL : cs->sbh;
ap_run_resume_connection(cs->c, cs->r);
}
/*
* Defer flush and close of the connection by adding it to defer_linger_chain,
* for a worker to grab it and do the job (should that be blocking).
* Pre-condition: nonblocking, can be called from anywhere provided cs is not
* in any timeout queue or in the pollset.
*/
static int defer_lingering_close(event_conn_state_t *cs)
{
ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, cs->c,
"deferring close from state %i", (int)cs->pub.state);
/* The connection is not shutdown() yet strictly speaking, but it's not
* in any queue nor handled by a worker either (will be very soon), so
* to account for it somewhere we bump lingering_count now (and set
* deferred_linger for process_lingering_close() to know).
*/
cs->pub.state = CONN_STATE_LINGER;
apr_atomic_inc32(&lingering_count);
cs->deferred_linger = 1;
for (;;) {
event_conn_state_t *chain = cs->chain = defer_linger_chain;
if (apr_atomic_casptr((void *)&defer_linger_chain, cs,
chain) != chain) {
/* Race lost, try again */
continue;
}
return 1;
}
}
/* Close the connection and release its resources (ptrans), either because an
* unrecoverable error occured (queues or pollset add/remove) or more usually
* if lingering close timed out.
* Pre-condition: nonblocking, can be called from anywhere provided cs is not
* in any timeout queue or in the pollset.
*/
static void close_connection(event_conn_state_t *cs)
{
ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, cs->c,
"closing connection from state %i", (int)cs->pub.state);
close_socket_nonblocking(cs->pfd.desc.s);
ap_queue_info_push_pool(worker_queue_info, cs->p);
}
/* Shutdown the connection in case of timeout, error or resources shortage.
* This starts short lingering close if not already there, or directly closes
* the connection otherwise.
* Pre-condition: nonblocking, can be called from anywhere provided cs is not
* in any timeout queue or in the pollset.
*/
static int shutdown_connection(event_conn_state_t *cs)
{
if (cs->pub.state < CONN_STATE_LINGER) {
apr_table_setn(cs->c->notes, "short-lingering-close", "1");
defer_lingering_close(cs);
}
else {
close_connection(cs);
}
return 1;
}
/*
* This runs before any non-MPM cleanup code on the connection;
* if the connection is currently suspended as far as modules
* know, provide notification of resumption.
*/
static apr_status_t ptrans_pre_cleanup(void *dummy)
{
event_conn_state_t *cs = dummy;
if (cs->suspended) {
notify_resume(cs, 1);
}
return APR_SUCCESS;
}
/*
* event_pre_read_request() and event_request_cleanup() track the
* current r for a given connection.
*/
static apr_status_t event_request_cleanup(void *dummy)
{
conn_rec *c = dummy;
event_conn_state_t *cs = ap_get_module_config(c->conn_config,
&mpm_event_module);
cs->r = NULL;
return APR_SUCCESS;
}
static void event_pre_read_request(request_rec *r, conn_rec *c)
{
event_conn_state_t *cs = ap_get_module_config(c->conn_config,
&mpm_event_module);
cs->r = r;
cs->sc = ap_get_module_config(ap_server_conf->module_config,
&mpm_event_module);
apr_pool_cleanup_register(r->pool, c, event_request_cleanup,
apr_pool_cleanup_null);
}
/*
* event_post_read_request() tracks the current server config for a
* given request.
*/
static int event_post_read_request(request_rec *r)
{
conn_rec *c = r->connection;
event_conn_state_t *cs = ap_get_module_config(c->conn_config,
&mpm_event_module);
/* To preserve legacy behaviour (consistent with other MPMs), use
* the keepalive timeout from the base server (first on this IP:port)
* when none is explicitly configured on this server.
*/
if (r->server->keep_alive_timeout_set) {
cs->sc = ap_get_module_config(r->server->module_config,
&mpm_event_module);
}
else {
cs->sc = ap_get_module_config(c->base_server->module_config,
&mpm_event_module);
}
return OK;
}
/* Forward declare */
static void process_lingering_close(event_conn_state_t *cs);
static void update_reqevents_from_sense(event_conn_state_t *cs, int sense)
{
if (sense < 0) {
sense = cs->pub.sense;
}
if (sense == CONN_SENSE_WANT_READ) {
cs->pfd.reqevents = APR_POLLIN | APR_POLLHUP;
}
else {
cs->pfd.reqevents = APR_POLLOUT;
}
/* POLLERR is usually returned event only, but some pollset
* backends may require it in reqevents to do the right thing,
* so it shouldn't hurt (ignored otherwise).
*/
cs->pfd.reqevents |= APR_POLLERR;
/* Reset to default for the next round */
cs->pub.sense = CONN_SENSE_DEFAULT;
}
/*
* process one connection in the worker
*/
static void process_socket(apr_thread_t *thd, apr_pool_t * p, apr_socket_t * sock,
event_conn_state_t * cs, int my_child_num,
int my_thread_num)
{
conn_rec *c;
long conn_id = ID_FROM_CHILD_THREAD(my_child_num, my_thread_num);
int clogging = 0, from_wc_q = 0;
apr_status_t rv;
int rc = OK;
if (cs == NULL) { /* This is a new connection */
listener_poll_type *pt = apr_pcalloc(p, sizeof(*pt));
cs = apr_pcalloc(p, sizeof(event_conn_state_t));
cs->bucket_alloc = apr_bucket_alloc_create(p);
ap_create_sb_handle(&cs->sbh, p, my_child_num, my_thread_num);
c = ap_run_create_connection(p, ap_server_conf, sock,
conn_id, cs->sbh, cs->bucket_alloc);
if (!c) {
ap_queue_info_push_pool(worker_queue_info, p);
return;
}
apr_atomic_inc32(&connection_count);
apr_pool_cleanup_register(c->pool, cs, decrement_connection_count,
apr_pool_cleanup_null);
ap_set_module_config(c->conn_config, &mpm_event_module, cs);
c->current_thread = thd;
c->cs = &cs->pub;
cs->c = c;
cs->p = p;
cs->sc = ap_get_module_config(ap_server_conf->module_config,
&mpm_event_module);
cs->pfd.desc_type = APR_POLL_SOCKET;
cs->pfd.desc.s = sock;
update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ);
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;
}
}
else if (cs->pub.state == CONN_STATE_WRITE_COMPLETION) {
from_wc_q = 1;
}
}
/*
* 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 interacts with
* the MPM through suspend/resume_connection() hooks, and/or registered
* poll callbacks (PT_USER), and/or registered timed callbacks triggered
* by timer events.
* 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) {
int pending = DECLINED;
ap_update_child_status(cs->sbh, SERVER_BUSY_WRITE, NULL);
if (from_wc_q) {
from_wc_q = 0; /* one shot */
pending = ap_run_output_pending(c);
}
else if (ap_filter_should_yield(c->output_filters)) {
pending = OK;
}
if (pending == OK || (pending == DECLINED &&
cs->pub.sense == CONN_SENSE_WANT_READ)) {
/* Still in WRITE_COMPLETION_STATE:
* Set a read/write timeout for this connection, and let the
* event thread poll for read/writeability.
*/
cs->queue_timestamp = apr_time_now();
notify_suspend(cs);
update_reqevents_from_sense(cs, -1);
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");
close_connection(cs);
signal_threads(ST_GRACEFUL);
}
else {
apr_thread_mutex_unlock(timeout_mutex);
}
return;
}
if (pending != DECLINED
|| c->aborted
|| c->keepalive != AP_CONN_KEEPALIVE) {
cs->pub.state = CONN_STATE_LINGER;
}
else if (ap_run_input_pending(c) == OK) {
cs->pub.state = CONN_STATE_READ_REQUEST_LINE;
goto read_request;
}
else if (!listener_may_exit) {
cs->pub.state = CONN_STATE_CHECK_REQUEST_LINE_READABLE;
}
else {
cs->pub.state = CONN_STATE_LINGER;
}
}
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. */
update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ);
apr_thread_mutex_lock(timeout_mutex);
TO_QUEUE_APPEND(cs->sc->ka_q, cs);
rv = apr_pollset_add(event_pollset, &cs->pfd);
if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) {
AP_DEBUG_ASSERT(0);
TO_QUEUE_REMOVE(cs->sc->ka_q, cs);
apr_thread_mutex_unlock(timeout_mutex);
ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03093)
"process_socket: apr_pollset_add failure for "
"keep alive");
close_connection(cs);
signal_threads(ST_GRACEFUL);
}
else {
apr_thread_mutex_unlock(timeout_mutex);
}
return;
}
if (cs->pub.state == CONN_STATE_SUSPENDED) {
cs->c->suspended_baton = cs;
apr_atomic_inc32(&suspended_count);
notify_suspend(cs);
return;
}
/* CONN_STATE_LINGER[_*] fall through process_lingering_close() */
if (cs->pub.state >= CONN_STATE_LINGER) {
process_lingering_close(cs);
return;
}
}
/* Put a SUSPENDED connection back into a queue. */
static apr_status_t event_resume_suspended (conn_rec *c)
{
event_conn_state_t* cs = (event_conn_state_t*) c->suspended_baton;
if (cs == NULL) {
ap_log_cerror (APLOG_MARK, LOG_WARNING, 0, c, APLOGNO(02615)
"event_resume_suspended: suspended_baton is NULL");
return APR_EGENERAL;
} else if (!cs->suspended) {
ap_log_cerror (APLOG_MARK, LOG_WARNING, 0, c, APLOGNO(02616)
"event_resume_suspended: Thread isn't suspended");
return APR_EGENERAL;
}
apr_atomic_dec32(&suspended_count);
c->suspended_baton = NULL;
if (cs->pub.state < CONN_STATE_LINGER) {
cs->queue_timestamp = apr_time_now();
cs->pub.state = CONN_STATE_WRITE_COMPLETION;
notify_suspend(cs);
update_reqevents_from_sense(cs, -1);
apr_thread_mutex_lock(timeout_mutex);
TO_QUEUE_APPEND(cs->sc->wc_q, cs);
apr_pollset_add(event_pollset, &cs->pfd);
apr_thread_mutex_unlock(timeout_mutex);
}
else {
cs->pub.state = CONN_STATE_LINGER;
process_lingering_close(cs);
}
return OK;
}
/* conns_this_child has gone to zero or below. See if the admin coded
"MaxConnectionsPerChild 0", and keep going in that case. Doing it this way
simplifies the hot path in worker_thread */
static void check_infinite_requests(void)
{
if (ap_max_requests_per_child) {
ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
"Stopping process due to MaxConnectionsPerChild");
signal_threads(ST_GRACEFUL);
}
else {
/* keep going */
conns_this_child = APR_INT32_MAX;
}
}
static int close_listeners(int *closed)
{
ap_log_error(APLOG_MARK, APLOG_TRACE6, 0, ap_server_conf,
"clos%s listeners (connection_count=%u)",
*closed ? "ed" : "ing", apr_atomic_read32(&connection_count));
if (!*closed) {
int i;
ap_close_listeners_ex(my_bucket->listeners);
*closed = 1; /* once */
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);
return 1;
}
return 0;
}
static void unblock_signal(int sig)
{
sigset_t sig_mask;
sigemptyset(&sig_mask);
sigaddset(&sig_mask, sig);
#if defined(SIGPROCMASK_SETS_THREAD_MASK)
sigprocmask(SIG_UNBLOCK, &sig_mask, NULL);
#else
pthread_sigmask(SIG_UNBLOCK, &sig_mask, NULL);
#endif
}
static void dummy_signal_handler(int sig)
{
/* XXX If specifying SIG_IGN is guaranteed to unblock a syscall,
* then we don't need this goofy function.
*/
}
#if HAVE_SERF
static apr_status_t s_socket_add(void *user_baton,
apr_pollfd_t *pfd,
void *serf_baton)
{
s_baton_t *s = (s_baton_t*)user_baton;
/* XXXXX: recycle listener_poll_types */
listener_poll_type *pt = ap_malloc(sizeof(*pt));
pt->type = PT_SERF;
pt->baton = serf_baton;
pfd->client_data = pt;
return apr_pollset_add(s->pollset, pfd);
}
static apr_status_t s_socket_remove(void *user_baton,
apr_pollfd_t *pfd,
void *serf_baton)
{
s_baton_t *s = (s_baton_t*)user_baton;
listener_poll_type *pt = pfd->client_data;
free(pt);
return apr_pollset_remove(s->pollset, pfd);
}
#endif
#if HAVE_SERF
static void init_serf(apr_pool_t *p)
{
s_baton_t *baton = NULL;
baton = apr_pcalloc(p, sizeof(*baton));
baton->pollset = event_pollset;
/* TODO: subpools, threads, reuse, etc. -- currently use malloc() inside :( */
baton->pool = p;
g_serf = serf_context_create_ex(baton,
s_socket_add,
s_socket_remove, p);
ap_register_provider(p, "mpm_serf",
"instance", "0", g_serf);
}
#endif
static apr_status_t push_timer2worker(timer_event_t* te)
{
return ap_queue_push_timer(worker_queue, te);
}
/*
* Pre-condition: cs is neither in event_pollset nor a timeout queue
* this function may only be called by the listener
*/
static apr_status_t push2worker(event_conn_state_t *cs, apr_socket_t *csd,
apr_pool_t *ptrans)
{
apr_status_t rc;
if (cs) {
csd = cs->pfd.desc.s;
ptrans = cs->p;
}
rc = ap_queue_push_socket(worker_queue, csd, cs, ptrans);
if (rc != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rc, ap_server_conf, APLOGNO(00471)
"push2worker: ap_queue_push_socket failed");
/* trash the connection; we couldn't queue the connected
* socket to a worker
*/
if (cs) {
shutdown_connection(cs);
}
else {
if (csd) {
close_socket_nonblocking(csd);
}
if (ptrans) {
ap_queue_info_push_pool(worker_queue_info, ptrans);
}
}
signal_threads(ST_GRACEFUL);
}
return rc;
}
/* get_worker:
* If *have_idle_worker_p == 0, reserve a worker thread, and set
* *have_idle_worker_p = 1.
* If *have_idle_worker_p is already 1, will do nothing.
* If blocking == 1, block if all workers are currently busy.
* If no worker was available immediately, will set *all_busy to 1.
* XXX: If there are no workers, we should not block immediately but
* XXX: close all keep-alive connections first.
*/
static void get_worker(int *have_idle_worker_p, int blocking, int *all_busy)
{
apr_status_t rc;
if (*have_idle_worker_p) {
/* already reserved a worker thread - must have hit a
* transient error on a previous pass
*/
return;
}
if (blocking)
rc = ap_queue_info_wait_for_idler(worker_queue_info, all_busy);
else
rc = ap_queue_info_try_get_idler(worker_queue_info);
if (rc == APR_SUCCESS || APR_STATUS_IS_EOF(rc)) {
*have_idle_worker_p = 1;
}
else if (!blocking && rc == APR_EAGAIN) {
*all_busy = 1;
}
else {
ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf, APLOGNO(00472)
"ap_queue_info_wait_for_idler failed. "
"Attempting to shutdown process gracefully");
signal_threads(ST_GRACEFUL);
}
}
/* Structures to reuse */
static timer_event_t timer_free_ring;
static apr_skiplist *timer_skiplist;
static volatile apr_time_t timers_next_expiry;
/* Same goal as for TIMEOUT_FUDGE_FACTOR (avoid extra poll calls), but applied
* to timers. Since their timeouts are custom (user defined), we can't be too
* approximative here (hence using 0.01s).
*/
#define EVENT_FUDGE_FACTOR apr_time_from_msec(10)
/* The following compare function is used by apr_skiplist_insert() to keep the
* elements (timers) sorted and provide O(log n) complexity (this is also true
* for apr_skiplist_{find,remove}(), but those are not used in MPM event where
* inserted timers are not searched nor removed, but with apr_skiplist_pop()
* which does use any compare function). It is meant to return 0 when a == b,
* <0 when a < b, and >0 when a > b. However apr_skiplist_insert() will not
* add duplicates (i.e. a == b), and apr_skiplist_add() is only available in
* APR 1.6, yet multiple timers could possibly be created in the same micro-
* second (duplicates with regard to apr_time_t); therefore we implement the
* compare function to return +1 instead of 0 when compared timers are equal,
* thus duplicates are still added after each other (in order of insertion).
*/
static int timer_comp(void *a, void *b)
{
apr_time_t t1 = (apr_time_t) ((timer_event_t *)a)->when;
apr_time_t t2 = (apr_time_t) ((timer_event_t *)b)->when;
AP_DEBUG_ASSERT(t1);
AP_DEBUG_ASSERT(t2);
return ((t1 < t2) ? -1 : 1);
}
static apr_thread_mutex_t *g_timer_skiplist_mtx;
static timer_event_t * event_get_timer_event(apr_time_t t,
ap_mpm_callback_fn_t *cbfn,
void *baton,
int insert,
apr_array_header_t *pfds)
{
timer_event_t *te;
apr_time_t now = (t < 0) ? 0 : apr_time_now();
/* oh yeah, and make locking smarter/fine grained. */
apr_thread_mutex_lock(g_timer_skiplist_mtx);
if (!APR_RING_EMPTY(&timer_free_ring.link, timer_event_t, link)) {
te = APR_RING_FIRST(&timer_free_ring.link);
APR_RING_REMOVE(te, link);
}
else {
te = apr_skiplist_alloc(timer_skiplist, sizeof(timer_event_t));
APR_RING_ELEM_INIT(te, link);
}
te->cbfunc = cbfn;
te->baton = baton;
te->canceled = 0;
te->when = now + t;
te->pfds = pfds;
if (insert) {
apr_time_t next_expiry;
/* Okay, add sorted by when.. */
apr_skiplist_insert(timer_skiplist, te);
/* Cheaply update the global timers_next_expiry with this event's
* if it expires before.
*/
next_expiry = timers_next_expiry;
if (!next_expiry || next_expiry > te->when + EVENT_FUDGE_FACTOR) {
timers_next_expiry = te->when;
/* Unblock the poll()ing listener for it to update its timeout. */
if (listener_is_wakeable) {
apr_pollset_wakeup(event_pollset);
}
}
}
apr_thread_mutex_unlock(g_timer_skiplist_mtx);
return te;
}
static apr_status_t event_register_timed_callback_ex(apr_time_t t,
ap_mpm_callback_fn_t *cbfn,
void *baton,
apr_array_header_t *pfds)
{
event_get_timer_event(t, cbfn, baton, 1, pfds);
return APR_SUCCESS;
}
static apr_status_t event_register_timed_callback(apr_time_t t,
ap_mpm_callback_fn_t *cbfn,
void *baton)
{
event_register_timed_callback_ex(t, cbfn, baton, NULL);
return APR_SUCCESS;
}
static apr_status_t event_cleanup_poll_callback(void *data)
{
apr_status_t final_rc = APR_SUCCESS;
apr_array_header_t *pfds = data;
int i;
for (i = 0; i < pfds->nelts; i++) {
apr_pollfd_t *pfd = (apr_pollfd_t *)pfds->elts + i;
if (pfd->client_data) {
apr_status_t rc;
rc = apr_pollset_remove(event_pollset, pfd);
if (rc != APR_SUCCESS && !APR_STATUS_IS_NOTFOUND(rc)) {
final_rc = rc;
}
pfd->client_data = NULL;
}
}
return final_rc;
}
static apr_status_t event_register_poll_callback_ex(apr_pool_t *p,
const apr_array_header_t *pfds,
ap_mpm_callback_fn_t *cbfn,
ap_mpm_callback_fn_t *tofn,
void *baton,
apr_time_t timeout)
{
socket_callback_baton_t *scb = apr_pcalloc(p, sizeof(*scb));
listener_poll_type *pt = apr_palloc(p, sizeof(*pt));
apr_status_t rc, final_rc = APR_SUCCESS;
int i;
pt->type = PT_USER;
pt->baton = scb;
scb->cbfunc = cbfn;
scb->user_baton = baton;
scb->pfds = apr_array_copy(p, pfds);
apr_pool_pre_cleanup_register(p, scb->pfds, event_cleanup_poll_callback);
for (i = 0; i < scb->pfds->nelts; i++) {
apr_pollfd_t *pfd = (apr_pollfd_t *)scb->pfds->elts + i;
if (pfd->reqevents) {
if (pfd->reqevents & APR_POLLIN) {
pfd->reqevents |= APR_POLLHUP;
}
pfd->reqevents |= APR_POLLERR;
pfd->client_data = pt;
}
else {
pfd->client_data = NULL;
}
}
if (timeout > 0) {
/* XXX: This cancel timer event can fire before the pollset is updated */
scb->cancel_event = event_get_timer_event(timeout, tofn, baton, 1, scb->pfds);
}
for (i = 0; i < scb->pfds->nelts; i++) {
apr_pollfd_t *pfd = (apr_pollfd_t *)scb->pfds->elts + i;
if (pfd->client_data) {
rc = apr_pollset_add(event_pollset, pfd);
if (rc != APR_SUCCESS) {
final_rc = rc;
}
}
}
return final_rc;
}
static apr_status_t event_register_poll_callback(apr_pool_t *p,
const apr_array_header_t *pfds,
ap_mpm_callback_fn_t *cbfn,
void *baton)
{
return event_register_poll_callback_ex(p,
pfds,
cbfn,
NULL, /* no timeout function */
baton,
0 /* no timeout */);
}
/*
* Flush data and close our side of the connection, then drain incoming data.
* If the latter would block put the connection in one of the linger timeout
* queues to be called back when ready, and repeat until it's closed by peer.
* Only to be called in the worker thread, and since it's in immediate call
* stack, we can afford a comfortable buffer size to consume data quickly.
* Pre-condition: cs is not in any timeout queue and not in the pollset,
* timeout_mutex is not locked
*/
#define LINGERING_BUF_SIZE (32 * 1024)
static void process_lingering_close(event_conn_state_t *cs)
{
apr_socket_t *csd = ap_get_conn_socket(cs->c);
char dummybuf[LINGERING_BUF_SIZE];
apr_size_t nbytes;
apr_status_t rv;
struct timeout_queue *q;
ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, cs->c,
"lingering close from state %i", (int)cs->pub.state);
AP_DEBUG_ASSERT(cs->pub.state >= CONN_STATE_LINGER);
if (cs->pub.state == CONN_STATE_LINGER) {
/* defer_lingering_close() may have bumped lingering_count already */
if (!cs->deferred_linger) {
apr_atomic_inc32(&lingering_count);
}
apr_socket_timeout_set(csd, apr_time_from_sec(SECONDS_TO_LINGER));
if (ap_start_lingering_close(cs->c)) {
notify_suspend(cs);
close_connection(cs);
return;
}
cs->queue_timestamp = apr_time_now();
/* Clear APR_INCOMPLETE_READ if it was ever set, we'll do the poll()
* at the listener only from now, if needed.
*/
apr_socket_opt_set(csd, APR_INCOMPLETE_READ, 0);
/*
* If some module requested a shortened waiting period, only wait for
* 2s (SECONDS_TO_LINGER). This is useful for mitigating certain
* DoS attacks.
*/
if (apr_table_get(cs->c->notes, "short-lingering-close")) {
cs->pub.state = CONN_STATE_LINGER_SHORT;
}
else {
cs->pub.state = CONN_STATE_LINGER_NORMAL;
}
notify_suspend(cs);
}
apr_socket_timeout_set(csd, 0);
do {
nbytes = sizeof(dummybuf);
rv = apr_socket_recv(csd, dummybuf, &nbytes);
} while (rv == APR_SUCCESS);
if (!APR_STATUS_IS_EAGAIN(rv)) {
close_connection(cs);
return;
}
/* (Re)queue the connection to come back when readable */
update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ);
q = (cs->pub.state == CONN_STATE_LINGER_SHORT) ? short_linger_q : linger_q;
apr_thread_mutex_lock(timeout_mutex);
TO_QUEUE_APPEND(q, cs);
rv = apr_pollset_add(event_pollset, &cs->pfd);
if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) {
AP_DEBUG_ASSERT(0);
TO_QUEUE_REMOVE(q, cs);
apr_thread_mutex_unlock(timeout_mutex);
ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03092)
"process_lingering_close: apr_pollset_add failure");
close_connection(cs);
signal_threads(ST_GRACEFUL);
return;
}
apr_thread_mutex_unlock(timeout_mutex);
}
/* call 'func' for all elements of 'q' above 'expiry'.
* Pre-condition: timeout_mutex must already be locked
* Post-condition: timeout_mutex will be locked again
*/
static void process_timeout_queue(struct timeout_queue *q, apr_time_t expiry,
int (*func)(event_conn_state_t *))
{
apr_uint32_t total = 0, count;
event_conn_state_t *first, *cs, *last;
struct event_conn_state_t trash;
struct timeout_queue *qp;
apr_status_t rv;
if (!*q->total) {
return;
}
APR_RING_INIT(&trash.timeout_list, event_conn_state_t, timeout_list);
for (qp = q; qp; qp = qp->next) {
count = 0;
cs = first = last = APR_RING_FIRST(&qp->head);
while (cs != APR_RING_SENTINEL(&qp->head, event_conn_state_t,
timeout_list)) {
/* Trash the entry if:
* - no expiry was given (zero means all), or
* - it expired (according to the queue timeout), or
* - the system clock skewed in the past: no entry should be
* registered above the given expiry (~now) + the queue
* timeout, we won't keep any here (eg. for centuries).
*
* Otherwise stop, no following entry will match thanks to the
* single timeout per queue (entries are added to the end!).
* This allows maintenance in O(1).
*/
if (expiry && cs->queue_timestamp + qp->timeout > expiry
&& cs->queue_timestamp < expiry + qp->timeout) {
/* Since this is the next expiring entry of this queue, update
* the global queues_next_expiry if it's later than this one.
*/
apr_time_t elem_expiry = cs->queue_timestamp + qp->timeout;
apr_time_t next_expiry = queues_next_expiry;
if (!next_expiry
|| next_expiry > elem_expiry + TIMEOUT_FUDGE_FACTOR) {
queues_next_expiry = elem_expiry;
}
break;
}
last = cs;
rv = apr_pollset_remove(event_pollset, &cs->pfd);
if (rv != APR_SUCCESS && !APR_STATUS_IS_NOTFOUND(rv)) {
AP_DEBUG_ASSERT(0);
ap_log_cerror(APLOG_MARK, APLOG_ERR, rv, cs->c, APLOGNO(00473)
"apr_pollset_remove failed");
}
cs = APR_RING_NEXT(cs, timeout_list);
count++;
}
if (!count)
continue;
APR_RING_UNSPLICE(first, last, timeout_list);
APR_RING_SPLICE_TAIL(&trash.timeout_list, first, last, event_conn_state_t,
timeout_list);
AP_DEBUG_ASSERT(*q->total >= count && qp->count >= count);
*q->total -= count;
qp->count -= count;
total += count;
}
if (!total)
return;
apr_thread_mutex_unlock(timeout_mutex);
first = APR_RING_FIRST(&trash.timeout_list);
do {
cs = APR_RING_NEXT(first, timeout_list);
TO_QUEUE_ELEM_INIT(first);
func(first);
first = cs;
} while (--total);
apr_thread_mutex_lock(timeout_mutex);
}
static void process_keepalive_queue(apr_time_t expiry)
{
/* If all workers are busy, we kill older keep-alive connections so
* that they may connect to another process.
*/
if (!expiry && *keepalive_q->total) {
ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
"All workers are busy or dying, will shutdown %u "
"keep-alive connections", *keepalive_q->total);
}
process_timeout_queue(keepalive_q, expiry, shutdown_connection);
}
static void * APR_THREAD_FUNC listener_thread(apr_thread_t * thd, void *dummy)
{
apr_status_t rc;
proc_info *ti = dummy;
int process_slot = ti->pslot;
struct process_score *ps = ap_get_scoreboard_process(process_slot);
int closed = 0;
int have_idle_worker = 0;
apr_time_t last_log;
last_log = apr_time_now();
free(ti);
#if HAVE_SERF
init_serf(apr_thread_pool_get(thd));
#endif
/* Unblock the signal used to wake this thread up, and set a handler for
* it.
*/
apr_signal(LISTENER_SIGNAL, dummy_signal_handler);
unblock_signal(LISTENER_SIGNAL);
for (;;) {
timer_event_t *te;
const apr_pollfd_t *out_pfd;
apr_int32_t num = 0;
apr_interval_time_t timeout;
socket_callback_baton_t *user_chain;
apr_time_t now, expiry = -1;
int workers_were_busy = 0;
if (conns_this_child <= 0)
check_infinite_requests();
if (listener_may_exit) {
int first_close = close_listeners(&closed);
if (terminate_mode == ST_UNGRACEFUL
|| apr_atomic_read32(&connection_count) == 0)
break;
/* Don't wait in poll() for the first close (i.e. dying now), we
* want to maintain the queues and schedule defer_linger_chain ASAP
* to kill kept-alive connection and shutdown the workers and child
* faster.
*/
if (first_close) {
goto do_maintenance; /* with expiry == -1 */
}
}
if (APLOGtrace6(ap_server_conf)) {
now = apr_time_now();
/* trace log status every second */
if (now - last_log > apr_time_from_sec(1)) {
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),
apr_atomic_read32(write_completion_q->total),
apr_atomic_read32(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);
}
}
#if HAVE_SERF
rc = serf_context_prerun(g_serf);
if (rc != APR_SUCCESS) {
/* TODO: what should we do here? ugh. */
}
#endif
/* Start with an infinite poll() timeout and update it according to
* the next expiring timer or queue entry. If there are none, either
* the listener is wakeable and it can poll() indefinitely until a wake
* up occurs, otherwise periodic checks (maintenance, shutdown, ...)
* must be performed.
*/
now = apr_time_now();
timeout = -1;
/* Push expired timers to a worker, the first remaining one determines
* the maximum time to poll() below, if any.
*/
expiry = timers_next_expiry;
if (expiry && expiry < now) {
apr_thread_mutex_lock(g_timer_skiplist_mtx);
while ((te = apr_skiplist_peek(timer_skiplist))) {
if (te->when > now) {
timers_next_expiry = te->when;
timeout = te->when - now;
break;
}
apr_skiplist_pop(timer_skiplist, NULL);
if (!te->canceled) {
if (te->pfds) {
/* remove all sockets from the pollset */
apr_pool_cleanup_run(te->pfds->pool, te->pfds,
event_cleanup_poll_callback);
}
push_timer2worker(te);
}
else {
APR_RING_INSERT_TAIL(&timer_free_ring.link, te,
timer_event_t, link);
}
}
if (!te) {
timers_next_expiry = 0;
}
apr_thread_mutex_unlock(g_timer_skiplist_mtx);
}
/* Same for queues, use their next expiry, if any. */
expiry = queues_next_expiry;
if (expiry
&& (timeout < 0
|| expiry <= now
|| timeout > expiry - now)) {
timeout = expiry > now ? expiry - now : 0;
}
/* When non-wakeable, don't wait more than 100 ms, in any case. */
#define NON_WAKEABLE_POLL_TIMEOUT apr_time_from_msec(100)
if (!listener_is_wakeable
&& (timeout < 0
|| timeout > NON_WAKEABLE_POLL_TIMEOUT)) {
timeout = NON_WAKEABLE_POLL_TIMEOUT;
}
else if (timeout > 0) {
/* apr_pollset_poll() might round down the timeout to milliseconds,
* let's forcibly round up here to never return before the timeout.
*/
timeout = apr_time_from_msec(
apr_time_as_msec(timeout + apr_time_from_msec(1) - 1)
);
}
ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, ap_server_conf,
"polling with timeout=%" APR_TIME_T_FMT
" queues_timeout=%" APR_TIME_T_FMT
" timers_timeout=%" APR_TIME_T_FMT,
timeout, queues_next_expiry - now,
timers_next_expiry - now);
rc = apr_pollset_poll(event_pollset, timeout, &num, &out_pfd);
if (rc != APR_SUCCESS) {
if (!APR_STATUS_IS_EINTR(rc) && !APR_STATUS_IS_TIMEUP(rc)) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rc, ap_server_conf,
APLOGNO(03267)
"apr_pollset_poll failed. Attempting to "
"shutdown process gracefully");
signal_threads(ST_GRACEFUL);
}
num = 0;
}
if (APLOGtrace7(ap_server_conf)) {
now = apr_time_now();
ap_log_error(APLOG_MARK, APLOG_TRACE7, rc, ap_server_conf,
"polled with num=%u exit=%d/%d conns=%d"
" queues_timeout=%" APR_TIME_T_FMT
" timers_timeout=%" APR_TIME_T_FMT,
num, listener_may_exit, dying,
apr_atomic_read32(&connection_count),
queues_next_expiry - now, timers_next_expiry - now);
}
/* XXX possible optimization: stash the current time for use as
* r->request_time for new requests or queues maintenance
*/
for (user_chain = NULL; num; --num, ++out_pfd) {
listener_poll_type *pt = (listener_poll_type *) out_pfd->client_data;
if (pt->type == PT_CSD) {
/* one of the sockets is readable */
event_conn_state_t *cs = (event_conn_state_t *) pt->baton;
struct timeout_queue *remove_from_q = NULL;
/* don't wait for a worker for a keepalive request or
* lingering close processing. */
int blocking = 0;
switch (cs->pub.state) {
case CONN_STATE_WRITE_COMPLETION:
remove_from_q = cs->sc->wc_q;
blocking = 1;
break;
case CONN_STATE_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");
close_connection(cs);
signal_threads(ST_GRACEFUL);
break;
}
/* If we don't get a worker immediately (nonblocking), we
* close the connection; the client can re-connect to a
* different process for keepalive, and for lingering close
* the connection will be shutdown so the choice is to favor
* incoming/alive connections.
*/
get_worker(&have_idle_worker, blocking,
&workers_were_busy);
if (!have_idle_worker) {
shutdown_connection(cs);
}
else if (push2worker(cs, NULL, NULL) == APR_SUCCESS) {
have_idle_worker = 0;
}
}
}
else if (pt->type == PT_ACCEPT && !listeners_disabled()) {
/* A Listener Socket is ready for an accept() */
if (workers_were_busy) {
disable_listensocks();
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
APLOGNO(03268)
"All workers busy, not accepting new conns "
"in this process");
}
else if (connections_above_limit(&workers_were_busy)) {
disable_listensocks();
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
APLOGNO(03269)
"Too many open connections (%u), "
"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));
}
else if (!listener_may_exit) {
void *csd = NULL;
ap_listen_rec *lr = (ap_listen_rec *) pt->baton;
apr_pool_t *ptrans; /* Pool for per-transaction stuff */
ap_queue_info_pop_pool(worker_queue_info, &ptrans);
if (ptrans == NULL) {
/* create a new transaction pool for each accepted socket */
apr_allocator_t *allocator = NULL;
rc = apr_allocator_create(&allocator);
if (rc == APR_SUCCESS) {
apr_allocator_max_free_set(allocator,
ap_max_mem_free);
rc = apr_pool_create_ex(&ptrans, pconf, NULL,
allocator);
if (rc == APR_SUCCESS) {
apr_pool_tag(ptrans, "transaction");
apr_allocator_owner_set(allocator, ptrans);
}
}
if (rc != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rc,
ap_server_conf, APLOGNO(03097)
"Failed to create transaction pool");
if (allocator) {
apr_allocator_destroy(allocator);
}
resource_shortage = 1;
signal_threads(ST_GRACEFUL);
continue;
}
}
get_worker(&have_idle_worker, 1, &workers_were_busy);
rc = lr->accept_func(&csd, lr, ptrans);
/* later we trash rv and rely on csd to indicate
* success/failure
*/
AP_DEBUG_ASSERT(rc == APR_SUCCESS || !csd);
if (rc == APR_EGENERAL) {
/* E[NM]FILE, ENOMEM, etc */
resource_shortage = 1;
signal_threads(ST_GRACEFUL);
}
else if (ap_accept_error_is_nonfatal(rc)) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, rc, ap_server_conf,
"accept() on client socket failed");
}
if (csd != NULL) {
conns_this_child--;
if (push2worker(NULL, csd, ptrans) == APR_SUCCESS) {
have_idle_worker = 0;
}
}
else {
ap_queue_info_push_pool(worker_queue_info, ptrans);
}
}
} /* if:else on pt->type */
#if HAVE_SERF
else if (pt->type == PT_SERF) {
/* send socket to serf. */
/* XXXX: this doesn't require get_worker() */
serf_event_trigger(g_serf, pt->baton, out_pfd);
}
#endif
else if (pt->type == PT_USER) {
socket_callback_baton_t *baton = pt->baton;
if (baton->cancel_event) {
baton->cancel_event->canceled = 1;
}
/* We only signal once per N sockets with this baton,
* and after this loop to avoid any race/lifetime issue
* with the user callback being called while we handle
* the same baton multiple times here.
*/
if (!baton->signaled) {
baton->signaled = 1;
baton->next = user_chain;
user_chain = baton;
}
}
} /* for processing poll */
/* Time to handle user callbacks chained above */
while (user_chain) {
socket_callback_baton_t *baton = user_chain;
user_chain = user_chain->next;
baton->next = NULL;
/* remove all sockets from the pollset */
apr_pool_cleanup_run(baton->pfds->pool, baton->pfds,
event_cleanup_poll_callback);
/* masquerade as a timer event that is firing */
te = event_get_timer_event(-1 /* fake timer */,
baton->cbfunc,
baton->user_baton,
0, /* don't insert it */
NULL /* no associated socket callback */);
push_timer2worker(te);
}
/* We process the timeout queues here only when the global
* queues_next_expiry is passed. This happens accurately since
* adding to the queues (in workers) can only decrease this expiry,
* while latest ones are only taken into account here (in listener)
* during queues' processing, with the lock held. This works both
* with and without wake-ability.
*/
expiry = queues_next_expiry;
do_maintenance:
if (expiry && expiry < (now = apr_time_now())) {
ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, ap_server_conf,
"queues maintenance with timeout=%" APR_TIME_T_FMT,
expiry > 0 ? expiry - now : -1);
apr_thread_mutex_lock(timeout_mutex);
/* Steps below will recompute this. */
queues_next_expiry = 0;
/* Step 1: keepalive timeouts */
if (workers_were_busy || dying) {
process_keepalive_queue(0); /* kill'em all \m/ */
}
else {
process_keepalive_queue(now);
}
/* Step 2: write completion timeouts */
process_timeout_queue(write_completion_q, now,
defer_lingering_close);
/* Step 3: (normal) lingering close completion timeouts */
if (dying && linger_q->timeout > short_linger_q->timeout) {
/* Dying, force short timeout for normal lingering close */
linger_q->timeout = short_linger_q->timeout;
}
process_timeout_queue(linger_q, now, shutdown_connection);
/* Step 4: (short) lingering close completion timeouts */
process_timeout_queue(short_linger_q, now, shutdown_connection);
apr_thread_mutex_unlock(timeout_mutex);
ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, ap_server_conf,
"queues maintained with timeout=%" APR_TIME_T_FMT,
queues_next_expiry > now ? queues_next_expiry - now
: -1);
ps->keep_alive = apr_atomic_read32(keepalive_q->total);
ps->write_completion = apr_atomic_read32(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)
&& apr_atomic_read32(keepalive_q->total)) {
apr_thread_mutex_lock(timeout_mutex);
process_keepalive_queue(0); /* kill'em all \m/ */
apr_thread_mutex_unlock(timeout_mutex);
ps->keep_alive = 0;
}
/* If there are some lingering closes to defer (to a worker), schedule
* them now. We might wakeup a worker spuriously if another one empties
* defer_linger_chain in the meantime, but there also may be no active
* or all busy workers for an undefined time. In any case a deferred
* lingering close can't starve if we do that here since the chain is
* filled only above in the listener and it's emptied only in the
* worker(s); thus a NULL here means it will stay so while the listener
* waits (possibly indefinitely) in poll().
*/
if (defer_linger_chain) {
get_worker(&have_idle_worker, 0, &workers_were_busy);
if (have_idle_worker
&& defer_linger_chain /* re-test */
&& push2worker(NULL, NULL, NULL) == APR_SUCCESS) {
have_idle_worker = 0;
}
}
if (listeners_disabled()
&& !workers_were_busy
&& !connections_above_limit(NULL)) {
enable_listensocks();
}
} /* listener main loop */
ap_queue_term(worker_queue);
apr_thread_exit(thd, APR_SUCCESS);
return NULL;
}
/*
* During graceful shutdown, if there are more running worker threads than
* open connections, exit one worker thread.
*
* return 1 if thread should exit, 0 if it should continue running.
*/
static int worker_thread_should_exit_early(void)
{
for (;;) {
apr_uint32_t conns = apr_atomic_read32(&connection_count);
apr_uint32_t dead = apr_atomic_read32(&threads_shutdown);
apr_uint32_t newdead;
AP_DEBUG_ASSERT(dead <= threads_per_child);
if (conns >= threads_per_child - dead)
return 0;
newdead = dead + 1;
if (apr_atomic_cas32(&threads_shutdown, newdead, dead) == dead) {
/*
* No other thread has exited in the mean time, safe to exit
* this one.
*/
return 1;
}
}
}
/* XXX For ungraceful termination/restart, we definitely don't want to
* wait for active connections to finish but we may want to wait
* for idle workers to get out of the queue code and release mutexes,
* since those mutexes are cleaned up pretty soon and some systems
* may not react favorably (i.e., segfault) if operations are attempted
* on cleaned-up mutexes.
*/
static void *APR_THREAD_FUNC worker_thread(apr_thread_t * thd, void *dummy)
{
proc_info *ti = dummy;
int process_slot = ti->pslot;
int thread_slot = ti->tslot;
apr_status_t rv;
int is_idle = 0;
free(ti);
ap_scoreboard_image->servers[process_slot][thread_slot].pid = ap_my_pid;
ap_scoreboard_image->servers[process_slot][thread_slot].tid = apr_os_thread_current();
ap_scoreboard_image->servers[process_slot][thread_slot].generation = retained->mpm->my_generation;
ap_update_child_status_from_indexes(process_slot, thread_slot,
SERVER_STARTING, NULL);
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,
APLOGNO(03270)
"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.link, te, timer_event_t, link);
apr_thread_mutex_unlock(g_timer_skiplist_mtx);
}
}
else {
is_idle = 0;
if (csd != NULL) {
worker_sockets[thread_slot] = csd;
process_socket(thd, ptrans, csd, cs, process_slot, thread_slot);
worker_sockets[thread_slot] = NULL;
}
}
/* If there are deferred lingering closes, handle them now. */
while (!workers_may_exit) {
cs = defer_linger_chain;
if (!cs) {
break;
}
if (apr_atomic_casptr((void *)&defer_linger_chain, cs->chain,
cs) != cs) {
/* Race lost, try again */
continue;
}
cs->chain = NULL;
AP_DEBUG_ASSERT(cs->pub.state == CONN_STATE_LINGER);
worker_sockets[thread_slot] = csd = cs->pfd.desc.s;
process_socket(thd, cs->p, csd, cs, process_slot, thread_slot);
worker_sockets[thread_slot] = NULL;
}
}
ap_update_child_status_from_indexes(process_slot, thread_slot,
dying ? SERVER_DEAD
: SERVER_GRACEFUL, NULL);
apr_thread_exit(thd, APR_SUCCESS);
return NULL;
}
static int check_signal(int signum)
{
switch (signum) {
case SIGTERM:
case SIGINT:
return 1;
}
return 0;
}
static void create_listener_thread(thread_starter * ts)
{
int my_child_num = ts->child_num_arg;
apr_threadattr_t *thread_attr = ts->threadattr;
proc_info *my_info;
apr_status_t rv;
my_info = (proc_info *) ap_malloc(sizeof(proc_info));
my_info->pslot = my_child_num;
my_info->tslot = -1; /* listener thread doesn't have a thread slot */
rv = 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.link, timer_event_t, link);
apr_skiplist_init(&timer_skiplist, pskip);
apr_skiplist_set_compare(timer_skiplist, timer_comp, timer_comp);
/* All threads (listener, workers) and synchronization objects (queues,
* pollset, mutexes...) created here should have at least the lifetime of
* the connections they handle (i.e. ptrans). We can't use this thread's
* self pool because all these objects survive it, nor use pchild or pconf
* directly because this starter thread races with other modules' runtime,
* nor finally pchild (or subpool thereof) because it is killed explicitly
* before pconf (thus connections/ptrans can live longer, which matters in
* ONE_PROCESS mode). So this leaves us with a subpool of pconf, created
* before any ptrans hence destroyed after.
*/
apr_pool_create(&pruntime, pconf);
apr_pool_tag(pruntime, "mpm_runtime");
/* We must create the fd queues before we start up the listener
* and worker threads. */
rv = ap_queue_create(&worker_queue, threads_per_child, pruntime);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03100)
"ap_queue_create() failed");
clean_child_exit(APEXIT_CHILDFATAL);
}
if (ap_max_mem_free != APR_ALLOCATOR_MAX_FREE_UNLIMITED) {
/* If we want to conserve memory, let's not keep an unlimited number of
* pools & allocators.
* XXX: This should probably be a separate config directive
*/
max_recycled_pools = threads_per_child * 3 / 4 ;
}
rv = ap_queue_info_create(&worker_queue_info, pruntime,
threads_per_child, max_recycled_pools);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03101)
"ap_queue_info_create() failed");
clean_child_exit(APEXIT_CHILDFATAL);
}
/* Create the timeout mutex and main pollset before the listener
* thread starts.
*/
rv = apr_thread_mutex_create(&timeout_mutex, APR_THREAD_MUTEX_DEFAULT,
pruntime);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03102)
"creation of the timeout mutex failed.");
clean_child_exit(APEXIT_CHILDFATAL);
}
/* Create the main pollset */
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 | APR_POLLHUP | APR_POLLERR;
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,
APLOGNO(03271)
"child %" APR_PID_T_FMT " isn't taking over "
"slots very quickly (%d of %d)",
ap_my_pid, threads_created,
threads_per_child);
}
prev_threads_created = threads_created;
}
}
/* What state should this child_main process be listed as in the
* scoreboard...?
* ap_update_child_status_from_indexes(my_child_num, i, SERVER_STARTING,
* (request_rec *) NULL);
*
* This state should be listed separately in the scoreboard, in some kind
* of process_status, not mixed in with the worker threads' status.
* "life_status" is almost right, but it's in the worker's structure, and
* the name could be clearer. gla
*/
apr_thread_exit(thd, APR_SUCCESS);
return NULL;
}
static void join_workers(apr_thread_t * listener, apr_thread_t ** threads)
{
int i;
apr_status_t rv, thread_rv;
if (listener) {
int iter;
/* deal with a rare timing window which affects waking up the
* listener thread... if the signal sent to the listener thread
* is delivered between the time it verifies that the
* listener_may_exit flag is clear and the time it enters a
* blocking syscall, the signal didn't do any good... work around
* that by sleeping briefly and sending it again
*/
iter = 0;
while (!dying) {
apr_sleep(apr_time_from_msec(500));
if (dying || ++iter > 10) {
break;
}
/* listener has not stopped accepting yet */
ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
"listener has not stopped accepting yet (%d iter)", iter);
wakeup_listener();
}
if (iter > 10) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00475)
"the listener thread didn't stop accepting");
}
else {
rv = apr_thread_join(&thread_rv, listener);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(00476)
"apr_thread_join: unable to join listener thread");
}
}
}
for (i = 0; i < threads_per_child; i++) {
if (threads[i]) { /* if we ever created this thread */
rv = apr_thread_join(&thread_rv, threads[i]);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(00477)
"apr_thread_join: unable to join worker "
"thread %d", i);
}
}
}
}
static void join_start_thread(apr_thread_t * start_thread_id)
{
apr_status_t rv, thread_rv;
start_thread_may_exit = 1; /* tell it to give up in case it is still
* trying to take over slots from a
* previous generation
*/
rv = apr_thread_join(&thread_rv, start_thread_id);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(00478)
"apr_thread_join: unable to join the start " "thread");
}
}
static void child_main(int child_num_arg, int child_bucket)
{
apr_thread_t **threads;
apr_status_t rv;
thread_starter *ts;
apr_threadattr_t *thread_attr;
apr_thread_t *start_thread_id;
int i;
/* for benefit of any hooks that run as this child initializes */
retained->mpm->mpm_state = AP_MPMQ_STARTING;
ap_my_pid = getpid();
ap_child_slot = child_num_arg;
ap_fatal_signal_child_setup(ap_server_conf);
/* Get a sub context for global allocations in this child, so that
* we can have cleanups occur when the child exits.
*/
apr_pool_create(&pchild, pconf);
apr_pool_tag(pchild, "pchild");
/* 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" (implicitly) MPM's signals.
*/
rv = apr_setup_signal_thread();
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(00479)
"Couldn't initialize signal thread");
clean_child_exit(APEXIT_CHILDFATAL);
}
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
*/
apr_signal(SIGTERM, dummy_signal_handler);
unblock_signal(SIGTERM);
/* Watch for any messages from the parent over the POD */
while (1) {
rv = ap_mpm_podx_check(my_bucket->pod);
if (rv == AP_MPM_PODX_NORESTART) {
/* see if termination was triggered while we slept */
switch (terminate_mode) {
case ST_GRACEFUL:
rv = AP_MPM_PODX_GRACEFUL;
break;
case ST_UNGRACEFUL:
rv = AP_MPM_PODX_RESTART;
break;
}
}
if (rv == AP_MPM_PODX_GRACEFUL || rv == AP_MPM_PODX_RESTART) {
/* make sure the start thread has finished;
* signal_threads() and join_workers depend on that
*/
join_start_thread(start_thread_id);
signal_threads(rv ==
AP_MPM_PODX_GRACEFUL ? ST_GRACEFUL : ST_UNGRACEFUL);
break;
}
}
/* A terminating signal was received. Now join each of the
* workers to clean them up.
* If the worker already exited, then the join frees
* their resources and returns.
* If the worker hasn't exited, then this blocks until
* they have (then cleans up).
*/
ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
"%s termination received, joining workers",
rv == AP_MPM_PODX_GRACEFUL ? "graceful" : "ungraceful");
join_workers(ts->listener, threads);
ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
"%s termination, workers joined, exiting",
rv == AP_MPM_PODX_GRACEFUL ? "graceful" : "ungraceful");
}
free(threads);
clean_child_exit(resource_shortage ? APEXIT_CHILDSICK : 0);
}
static int make_child(server_rec * s, int slot, int bucket)
{
int pid;
if (slot + 1 > retained->max_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;
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;
int bucket = i % num_buckets;
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
&& 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
&& bucket == child_bucket
&& 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[child_slot % num_buckets] = 1;
}
else if (remaining_children_to_start) {
/* we're still doing a 1-for-1 replacement of dead
* children with new children
*/
make_child(ap_server_conf, child_slot,
child_slot % num_buckets);
--remaining_children_to_start;
}
}
#if APR_HAS_OTHER_CHILD
else if (apr_proc_other_child_alert(&pid, APR_OC_REASON_DEATH,
status) == 0) {
/* handled */
}
#endif
else if (retained->mpm->was_graceful) {
/* Great, we've probably just lost a slot in the
* scoreboard. Somehow we don't know about this child.
*/
ap_log_error(APLOG_MARK, APLOG_WARNING, 0,
ap_server_conf, APLOGNO(00488)
"long lost child came home! (pid %ld)",
(long) pid.pid);
}
/* Don't perform idle maintenance when a child dies,
* only do it when there's a timeout. Remember only a
* finite number of children can die, and it's pretty
* pathological for a lot to die suddenly.
*/
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), APLOGNO(03272)
"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), APLOGNO(03273)
"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), APLOGNO(03274)
"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));
if (retained->idle_spawn_rate) /* NULL at startup */
memcpy(new_ptr, retained->idle_spawn_rate,
retained->mpm->num_buckets * sizeof(int));
retained->idle_spawn_rate = new_ptr;
retained->mpm->max_buckets = new_max;
}
if (retained->mpm->num_buckets < num_buckets) {
int rate_max = 1;
/* If new buckets are added, set their idle spawn rate to
* the highest so far, so that they get filled as quickly
* as the existing ones.
*/
for (i = 0; i < retained->mpm->num_buckets; i++) {
if (rate_max < retained->idle_spawn_rate[i]) {
rate_max = retained->idle_spawn_rate[i];
}
}
for (/* up to date i */; i < num_buckets; i++) {
retained->idle_spawn_rate[i] = rate_max;
}
}
retained->mpm->num_buckets = num_buckets;
/* 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;
listener_is_wakeable = 0;
return OK;
}
static int event_post_config(apr_pool_t *pconf, apr_pool_t *plog,
apr_pool_t *ptemp, server_rec *s)
{
struct {
struct timeout_queue *tail, *q;
apr_hash_t *hash;
} 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_force_set_tz(p);
ap_hook_open_logs(event_open_logs, NULL, aszSucc, APR_HOOK_REALLY_FIRST);
/* we need to set the MPM state before other pre-config hooks use MPM query
* to retrieve it, so register as REALLY_FIRST
*/
ap_hook_pre_config(event_pre_config, NULL, NULL, APR_HOOK_REALLY_FIRST);
ap_hook_post_config(event_post_config, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_check_config(event_check_config, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_mpm(event_run, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_mpm_query(event_query, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_mpm_register_timed_callback(event_register_timed_callback, NULL, NULL,
APR_HOOK_MIDDLE);
ap_hook_mpm_register_poll_callback(event_register_poll_callback,
NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_mpm_register_poll_callback_timeout(event_register_poll_callback_ex,
NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_pre_read_request(event_pre_read_request, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_post_read_request(event_post_read_request, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_mpm_get_name(event_get_name, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_mpm_resume_suspended(event_resume_suspended, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_pre_connection(event_pre_connection, NULL, NULL, APR_HOOK_REALLY_FIRST);
ap_hook_protocol_switch(event_protocol_switch, NULL, NULL, APR_HOOK_REALLY_FIRST);
}
static const char *set_daemons_to_start(cmd_parms *cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
ap_daemons_to_start = atoi(arg);
return NULL;
}
static const char *set_min_spare_threads(cmd_parms * cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
min_spare_threads = atoi(arg);
return NULL;
}
static const char *set_max_spare_threads(cmd_parms * cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
max_spare_threads = atoi(arg);
return NULL;
}
static const char *set_max_workers(cmd_parms * cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
if (!strcasecmp(cmd->cmd->name, "MaxClients")) {
ap_log_error(APLOG_MARK, APLOG_INFO, 0, NULL, APLOGNO(00521)
"MaxClients is deprecated, use MaxRequestWorkers "
"instead.");
}
max_workers = atoi(arg);
return NULL;
}
static const char *set_threads_per_child(cmd_parms * cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
threads_per_child = atoi(arg);
return NULL;
}
static const char *set_server_limit (cmd_parms *cmd, void *dummy, const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
server_limit = atoi(arg);
return NULL;
}
static const char *set_thread_limit(cmd_parms * cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
thread_limit = atoi(arg);
return NULL;
}
static const char *set_worker_factor(cmd_parms * cmd, void *dummy,
const char *arg)
{
double val;
char *endptr;
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
val = strtod(arg, &endptr);
if (*endptr)
return "error parsing value";
if (val <= 0)
return "AsyncRequestWorkerFactor argument must be a positive number";
worker_factor = val * WORKER_FACTOR_SCALE;
if (worker_factor < WORKER_FACTOR_SCALE) {
worker_factor = WORKER_FACTOR_SCALE;
}
return NULL;
}
static const command_rec event_cmds[] = {
LISTEN_COMMANDS,
AP_INIT_TAKE1("StartServers", set_daemons_to_start, NULL, RSRC_CONF,
"Number of child processes launched at server startup"),
AP_INIT_TAKE1("ServerLimit", set_server_limit, NULL, RSRC_CONF,
"Maximum number of child processes for this run of Apache"),
AP_INIT_TAKE1("MinSpareThreads", set_min_spare_threads, NULL, RSRC_CONF,
"Minimum number of idle threads, to handle request spikes"),
AP_INIT_TAKE1("MaxSpareThreads", set_max_spare_threads, NULL, RSRC_CONF,
"Maximum number of idle threads"),
AP_INIT_TAKE1("MaxClients", set_max_workers, NULL, RSRC_CONF,
"Deprecated name of MaxRequestWorkers"),
AP_INIT_TAKE1("MaxRequestWorkers", set_max_workers, NULL, RSRC_CONF,
"Maximum number of threads alive at the same time"),
AP_INIT_TAKE1("ThreadsPerChild", set_threads_per_child, NULL, RSRC_CONF,
"Number of threads each child creates"),
AP_INIT_TAKE1("ThreadLimit", set_thread_limit, NULL, RSRC_CONF,
"Maximum number of worker threads per child process for this "
"run of Apache - Upper limit for ThreadsPerChild"),
AP_INIT_TAKE1("AsyncRequestWorkerFactor", set_worker_factor, NULL, RSRC_CONF,
"How many additional connects will be accepted per idle "
"worker thread"),
AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND,
{NULL}
};
AP_DECLARE_MODULE(mpm_event) = {
MPM20_MODULE_STUFF,
NULL, /* hook to run before apache parses args */
NULL, /* create per-directory config structure */
NULL, /* merge per-directory config structures */
NULL, /* create per-server config structure */
NULL, /* merge per-server config structures */
event_cmds, /* command apr_table_t */
event_hooks /* register_hooks */
};