/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* This MPM tries to fix the 'keep alive problem' in HTTP.
*
* After a client completes the first request, the client can keep the
* connection open to send more requests with the same socket. This can save
* significant overhead in creating TCP connections. However, the major
* disadvantage is that Apache traditionally keeps an entire child
* process/thread waiting for data from the client. To solve this problem,
* this MPM has a dedicated thread for handling both the Listening sockets,
* and all sockets that are in a Keep Alive status.
*
* The MPM assumes the underlying apr_pollset implementation is somewhat
* threadsafe. This currently is only compatible with KQueue and EPoll. This
* enables the MPM to avoid extra high level locking or having to wake up the
* listener thread when a keep-alive socket needs to be sent to it.
*
* This MPM does not perform well on older platforms that do not have very good
* threading, like Linux with a 2.4 kernel, but this does not matter, since we
* require EPoll or KQueue.
*
* For FreeBSD, use 5.3. It is possible to run this MPM on FreeBSD 5.2.1, if
* you use libkse (see `man libmap.conf`).
*
* For NetBSD, use at least 2.0.
*
* For Linux, you should use a 2.6 kernel, and make sure your glibc has epoll
* support compiled in.
*
*/
#include "apr.h"
#include "apr_portable.h"
#include "apr_strings.h"
#include "apr_file_io.h"
#include "apr_thread_proc.h"
#include "apr_signal.h"
#include "apr_thread_mutex.h"
#include "apr_poll.h"
#include "apr_ring.h"
#include "apr_queue.h"
#include "apr_atomic.h"
#define APR_WANT_STRFUNC
#include "apr_want.h"
#include "apr_version.h"
#include <stdlib.h>
#if APR_HAVE_UNISTD_H
#include <unistd.h>
#endif
#if APR_HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if APR_HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#ifdef HAVE_SYS_PROCESSOR_H
#include <sys/processor.h>
/* for bindprocessor() */
#endif
#if !APR_HAS_THREADS
#error The Event MPM requires APR threads, but they are unavailable.
#endif
#include "ap_config.h"
#include "httpd.h"
#include "http_main.h"
#include "http_log.h"
#include "http_config.h" /* for read_config */
#include "http_core.h" /* for get_remote_host */
#include "http_connection.h"
#include "http_protocol.h"
#include "ap_mpm.h"
#include "mpm_common.h"
#include "ap_listen.h"
#include "scoreboard.h"
#include "mpm_fdqueue.h"
#include "mpm_default.h"
#include "http_vhost.h"
#include "unixd.h"
#include "apr_skiplist.h"
#include <signal.h>
#include <limits.h>
/* for INT_MAX */
/* Limit on the total --- clients will be locked out if more servers than
* this are needed. It is intended solely to keep the server from crashing
* when things get out of hand.
*
* We keep a hard maximum number of servers, for two reasons --- first off,
* in case something goes seriously wrong, we want to stop the fork bomb
* short of actually crashing the machine we're running on by filling some
* kernel table. Secondly, it keeps the size of the scoreboard file small
* enough that we can read the whole thing without worrying too much about
* the overhead.
*/
#ifndef DEFAULT_SERVER_LIMIT
#define DEFAULT_SERVER_LIMIT 16
#endif
/* Admin can't tune ServerLimit beyond MAX_SERVER_LIMIT. We want
* some sort of compile-time limit to help catch typos.
*/
#ifndef MAX_SERVER_LIMIT
#define MAX_SERVER_LIMIT 20000
#endif
/* Limit on the threads per process. Clients will be locked out if more than
* this are needed.
*
* We keep this for one reason it keeps the size of the scoreboard file small
* enough that we can read the whole thing without worrying too much about
* the overhead.
*/
#ifndef DEFAULT_THREAD_LIMIT
#define DEFAULT_THREAD_LIMIT 64
#endif
/* Admin can't tune ThreadLimit beyond MAX_THREAD_LIMIT. We want
* some sort of compile-time limit to help catch typos.
*/
#ifndef MAX_THREAD_LIMIT
#define MAX_THREAD_LIMIT 100000
#endif
#define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid)
#if !APR_VERSION_AT_LEAST(1,4,0)
#define apr_time_from_msec(x) (x * 1000)
#endif
#define CONN_STATE_IS_LINGERING_CLOSE(s) ((s) >= CONN_STATE_LINGER && \
(s) <= CONN_STATE_LINGER_SHORT)
#ifndef MAX_SECS_TO_LINGER
#define MAX_SECS_TO_LINGER 30
#endif
#define SECONDS_TO_LINGER 2
/*
* Actual definitions of config globals
*/
#ifndef DEFAULT_WORKER_FACTOR
#define DEFAULT_WORKER_FACTOR 2
#endif
#define WORKER_FACTOR_SCALE 16
/* scale factor to allow fractional values */
static unsigned int worker_factor = DEFAULT_WORKER_FACTOR * WORKER_FACTOR_SCALE;
/* AsyncRequestWorkerFactor * 16 */
static int threads_per_child = 0;
/* ThreadsPerChild */
static int ap_daemons_to_start = 0;
/* StartServers */
static int min_spare_threads = 0;
/* MinSpareThreads */
static int max_spare_threads = 0;
/* MaxSpareThreads */
static int active_daemons_limit = 0;
/* MaxRequestWorkers / ThreadsPerChild */
static int max_workers = 0;
/* MaxRequestWorkers */
static int server_limit = 0;
/* ServerLimit */
static int thread_limit = 0;
/* ThreadLimit */
static int had_healthy_child = 0;
static volatile int dying = 0;
static volatile int workers_may_exit = 0;
static volatile int start_thread_may_exit = 0;
static volatile int listener_may_exit = 0;
static int listener_is_wakeable = 0;
/* Pollset supports APR_POLLSET_WAKEABLE */
static int num_listensocks = 0;
static apr_int32_t conns_this_child;
/* MaxConnectionsPerChild, only access
in listener thread */
static apr_uint32_t connection_count = 0;
/* Number of open connections */
static apr_uint32_t lingering_count = 0;
/* Number of connections in lingering close */
static apr_uint32_t suspended_count = 0;
/* Number of suspended connections */
static apr_uint32_t clogged_count = 0;
/* Number of threads processing ssl conns */
static apr_uint32_t threads_shutdown = 0;
/* Number of threads that have shutdown
early during graceful termination */
static int resource_shortage = 0;
static fd_queue_t *worker_queue;
static fd_queue_info_t *worker_queue_info;
static apr_thread_mutex_t *timeout_mutex;
module AP_MODULE_DECLARE_DATA mpm_event_module;
/* forward declare */
struct event_srv_cfg_s;
typedef struct event_srv_cfg_s event_srv_cfg;
static apr_pollfd_t *listener_pollfd;
/*
* The pollset for sockets that are in any of the timeout queues. Currently
* we use the timeout_mutex to make sure that connections are added/removed
* atomically to/from both event_pollset and a timeout queue. Otherwise
* some confusion can happen under high load if timeout queues and pollset
* get out of sync.
* XXX: It should be possible to make the lock unnecessary in many or even all
* XXX: cases.
*/
static apr_pollset_t *event_pollset;
typedef struct event_conn_state_t event_conn_state_t;
/*
* The chain of connections to be shutdown by a worker thread (deferred),
* linked list updated atomically.
*/
static event_conn_state_t *
volatile defer_linger_chain;
struct event_conn_state_t {
/** APR_RING of expiration timeouts */
APR_RING_ENTRY(event_conn_state_t) timeout_list;
/** the time when the entry was queued */
apr_time_t queue_timestamp;
/** connection record this struct refers to */
conn_rec *c;
/** request record (if any) this struct refers to */
request_rec *r;
/** server config this struct refers to */
event_srv_cfg *sc;
/** scoreboard handle for the conn_rec */
ap_sb_handle_t *sbh;
/** is the current conn_rec suspended? (disassociated with
* a particular MPM thread; for suspend_/resume_connection
* hooks)
*/
int suspended;
/** memory pool to allocate from */
apr_pool_t *p;
/** bucket allocator */
apr_bucket_alloc_t *bucket_alloc;
/** poll file descriptor information */
apr_pollfd_t pfd;
/** public parts of the connection state */
conn_state_t pub;
/** chaining in defer_linger_chain */
struct event_conn_state_t *chain;
unsigned int
/** Is lingering close from defer_lingering_close()? */
deferred_linger :1,
/** Has ap_start_lingering_close() been called? */
linger_started :1;
};
APR_RING_HEAD(timeout_head_t, event_conn_state_t);
struct timeout_queue {
struct timeout_head_t head;
apr_interval_time_t timeout;
apr_uint32_t count;
/* for this queue */
apr_uint32_t *total;
/* for all chained/related queues */
struct timeout_queue *next;
/* chaining */
};
/*
* Several timeout queues that use different timeouts, so that we always can
* simply append to the end.
* waitio_q uses vhost's TimeOut
* write_completion_q uses vhost's TimeOut
* keepalive_q uses vhost's KeepAliveTimeOut
* linger_q uses MAX_SECS_TO_LINGER
* short_linger_q uses SECONDS_TO_LINGER
*/
static struct timeout_queue *waitio_q,
*write_completion_q,
*keepalive_q,
*linger_q,
*short_linger_q;
static volatile apr_time_t queues_next_expiry;
/* Prevent extra poll/wakeup calls for timeouts close in the future (queues
* have the granularity of a second anyway).
* XXX: Wouldn't 0.5s (instead of 0.1s) be "enough"?
*/
#define TIMEOUT_FUDGE_FACTOR apr_time_from_msec(100)
/*
* Macros for accessing struct timeout_queue.
* For TO_QUEUE_APPEND and TO_QUEUE_REMOVE, timeout_mutex must be held.
*/
static void TO_QUEUE_APPEND(
struct timeout_queue *q, event_conn_state_t *el)
{
apr_time_t elem_expiry;
apr_time_t next_expiry;
APR_RING_INSERT_TAIL(&q->head, el, event_conn_state_t, timeout_list);
++*q->total;
++q->count;
/* Cheaply update the global queues_next_expiry with the one of the
* first entry of this queue (oldest) if it expires before.
*/
el = APR_RING_FIRST(&q->head);
elem_expiry = el->queue_timestamp + q->timeout;
next_expiry = queues_next_expiry;
if (!next_expiry || next_expiry > elem_expiry + TIMEOUT_FUDGE_FACTOR) {
queues_next_expiry = elem_expiry;
/* Unblock the poll()ing listener for it to update its timeout. */
if (listener_is_wakeable) {
apr_pollset_wakeup(event_pollset);
}
}
}
static void TO_QUEUE_REMOVE(
struct timeout_queue *q, event_conn_state_t *el)
{
APR_RING_REMOVE(el, timeout_list);
APR_RING_ELEM_INIT(el, timeout_list);
--*q->total;
--q->count;
}
static struct timeout_queue *TO_QUEUE_MAKE(apr_pool_t *p, apr_time_t t,
struct timeout_queue *ref)
{
struct timeout_queue *q;
q = apr_pcalloc(p,
sizeof *q);
APR_RING_INIT(&q->head, event_conn_state_t, timeout_list);
q->total = (ref) ? ref->total : apr_pcalloc(p,
sizeof *q->total);
q->timeout = t;
return q;
}
#define TO_QUEUE_ELEM_INIT(el) \
APR_RING_ELEM_INIT((el), timeout_list)
/* The structure used to pass unique initialization info to each thread */
typedef struct
{
int pslot;
/* process slot */
int tslot;
/* worker slot of the thread */
} proc_info;
/* Structure used to pass information to the thread responsible for
* creating the rest of the threads.
*/
typedef struct
{
apr_thread_t **threads;
apr_thread_t *listener;
int child_num_arg;
apr_threadattr_t *threadattr;
} thread_starter;
typedef enum
{
PT_CSD,
PT_ACCEPT
} poll_type_e;
typedef struct
{
poll_type_e type;
void *baton;
} listener_poll_type;
/* data retained by event across load/unload of the module
* allocated on first call to pre-config hook; located on
* subsequent calls to pre-config hook
*/
typedef struct event_retained_data {
ap_unixd_mpm_retained_data *mpm;
int first_server_limit;
int first_thread_limit;
int sick_child_detected;
int maxclients_reported;
int near_maxclients_reported;
/*
* The max child slot ever assigned, preserved across restarts. Necessary
* to deal with MaxRequestWorkers changes across AP_SIG_GRACEFUL restarts.
* We use this value to optimize routines that have to scan the entire
* scoreboard.
*/
int max_daemon_used;
/*
* All running workers, active and shutting down, including those that
* may be left from before a graceful restart.
* Not kept up-to-date when shutdown is pending.
*/
int total_daemons;
/*
* Workers that still active, i.e. are not shutting down gracefully.
*/
int active_daemons;
/*
* idle_spawn_rate is the number of children that will be spawned on the
* next maintenance cycle if there aren't enough idle servers. It is
* maintained per listeners bucket, doubled up to MAX_SPAWN_RATE, and
* reset only when a cycle goes by without the need to spawn.
*/
int *idle_spawn_rate;
#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 *io_q,
*wc_q,
*ka_q;
};
#define ID_FROM_CHILD_THREAD(c, t) ((c * thread_limit) + t)
/* The event MPM respects a couple of runtime flags that can aid
* in debugging. Setting the -DNO_DETACH flag will prevent the root process
* from detaching from its controlling terminal. Additionally, setting
* the -DONE_PROCESS flag (which implies -DNO_DETACH) will get you the
* child_main loop running in the process which originally started up.
* This gives you a pretty nice debugging environment. (You'll get a SIGHUP
* early in standalone_main; just continue through. This is the server
* trying to kill off any child processes which it might have lying
* around --- Apache doesn't keep track of their pids, it just sends
* SIGHUP to the process group, ignoring it in the root process.
* Continue through and you'll be fine.).
*/
static int one_process = 0;
#ifdef DEBUG_SIGSTOP
int raise_sigstop_flags;
#endif
static apr_pool_t *pconf;
/* Pool for config stuff */
static apr_pool_t *pchild;
/* Pool for httpd child stuff */
static apr_pool_t *pruntime;
/* Pool for MPM threads stuff */
static pid_t ap_my_pid;
/* Linux getpid() doesn't work except in main
thread. Use this instead */
static pid_t parent_pid;
static apr_os_thread_t *listener_os_thread;
static int ap_child_slot;
/* Current child process slot in scoreboard */
/* The LISTENER_SIGNAL signal will be sent from the main thread to the
* listener thread to wake it up for graceful termination (what a child
* process from an old generation does when the admin does "apachectl
* graceful"). This signal will be blocked in all threads of a child
* process except for the listener thread.
*/
#define LISTENER_SIGNAL SIGHUP
/* An array of socket descriptors in use by each thread used to
* perform a non-graceful (forced) shutdown of the server.
*/
static apr_socket_t **worker_sockets;
static volatile apr_uint32_t listensocks_disabled;
static void disable_listensocks(
void)
{
int i;
if (apr_atomic_cas32(&listensocks_disabled, 1, 0) != 0) {
return;
}
if (event_pollset) {
for (i = 0; i < num_listensocks; i++) {
apr_pollset_remove(event_pollset, &listener_pollfd[i]);
}
}
ap_scoreboard_image->parent[ap_child_slot].not_accepting = 1;
}
static void enable_listensocks(
void)
{
int i;
if (listener_may_exit
|| apr_atomic_cas32(&listensocks_disabled, 0, 1) != 1) {
return;
}
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00457)
"Accepting new connections again: "
"%u active conns (%u lingering/%u clogged/%u suspended), "
"%u idle workers",
apr_atomic_read32(&connection_count),
apr_atomic_read32(&lingering_count),
apr_atomic_read32(&clogged_count),
apr_atomic_read32(&suspended_count),
ap_queue_info_num_idlers(worker_queue_info));
for (i = 0; i < num_listensocks; i++)
apr_pollset_add(event_pollset, &listener_pollfd[i]);
/*
* XXX: This is not yet optimal. If many workers suddenly become available,
* XXX: the parent may kill some processes off too soon.
*/
ap_scoreboard_image->parent[ap_child_slot].not_accepting = 0;
}
static APR_INLINE apr_uint32_t listeners_disabled(
void)
{
return apr_atomic_read32(&listensocks_disabled);
}
static APR_INLINE
int connections_above_limit(
int *busy)
{
apr_uint32_t i_count = ap_queue_info_num_idlers(worker_queue_info);
if (i_count > 0) {
apr_uint32_t c_count = apr_atomic_read32(&connection_count);
apr_uint32_t l_count = apr_atomic_read32(&lingering_count);
if (c_count <= l_count
/* Off by 'listeners_disabled()' to avoid flip flop */
|| c_count - l_count < (apr_uint32_t)threads_per_child +
(i_count - listeners_disabled()) *
(worker_factor / WORKER_FACTOR_SCALE)) {
return 0;
}
}
else if (busy) {
*busy = 1;
}
return 1;
}
static APR_INLINE
int should_enable_listensocks(
void)
{
return !dying && listeners_disabled() && !connections_above_limit(NULL);
}
static void close_socket_nonblocking_(apr_socket_t *csd,
const char *from,
int line)
{
apr_status_t rv;
apr_os_sock_t fd = -1;
/* close_worker_sockets() may have closed it already */
rv = apr_os_sock_get(&fd, csd);
ap_log_error(APLOG_MARK, APLOG_TRACE8, 0, ap_server_conf,
"closing socket %i/%pp from %s:%i", (
int)fd, csd, from, line);
if (rv == APR_SUCCESS && fd == -1) {
return;
}
apr_socket_timeout_set(csd, 0);
rv = apr_socket_close(csd);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(00468)
"error closing socket");
AP_DEBUG_ASSERT(0);
}
}
#define close_socket_nonblocking(csd) \
close_socket_nonblocking_(csd, __FUNCTION__, __LINE__)
static void close_worker_sockets(
void)
{
int i;
for (i = 0; i < threads_per_child; i++) {
apr_socket_t *csd = worker_sockets[i];
if (csd) {
worker_sockets[i] = NULL;
close_socket_nonblocking(csd);
}
}
}
static void wakeup_listener(
void)
{
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
"wake up listener%s", listener_may_exit ?
" again" :
"");
listener_may_exit = 1;
disable_listensocks();
/* Unblock the listener if it's poll()ing */
if (event_pollset && listener_is_wakeable) {
apr_pollset_wakeup(event_pollset);
}
/* unblock the listener if it's waiting for a worker */
if (worker_queue_info) {
ap_queue_info_term(worker_queue_info);
}
if (!listener_os_thread) {
/* XXX there is an obscure path that this doesn't handle perfectly:
* right after listener thread is created but before
* listener_os_thread is set, the first worker thread hits an
* error and starts graceful termination
*/
return;
}
/*
* we should just be able to "kill(ap_my_pid, LISTENER_SIGNAL)" on all
* platforms and wake up the listener thread since it is the only thread
* with SIGHUP unblocked, but that doesn't work on Linux
*/
#ifdef HAVE_PTHREAD_KILL
pthread_kill(*listener_os_thread, LISTENER_SIGNAL);
#else
kill(ap_my_pid, LISTENER_SIGNAL);
#endif
}
#define ST_INIT 0
#define ST_GRACEFUL 1
#define ST_UNGRACEFUL 2
static int terminate_mode = ST_INIT;
static void signal_threads(
int mode)
{
if (terminate_mode >= mode) {
return;
}
terminate_mode = mode;
retained->mpm->mpm_state = AP_MPMQ_STOPPING;
/* in case we weren't called from the listener thread, wake up the
* listener thread
*/
wakeup_listener();
/* for ungraceful termination, let the workers exit now;
* for graceful termination, the listener thread will notify the
* workers to exit once it has stopped accepting new connections
*/
if (mode == ST_UNGRACEFUL) {
workers_may_exit = 1;
ap_queue_interrupt_all(worker_queue);
close_worker_sockets();
/* forcefully kill all current connections */
}
ap_run_child_stopping(pchild, mode == ST_GRACEFUL);
}
static int event_query(
int query_code,
int *result, apr_status_t *rv)
{
*rv = APR_SUCCESS;
switch (query_code) {
case AP_MPMQ_MAX_DAEMON_USED:
*result = retained->max_daemon_used;
break;
case AP_MPMQ_IS_THREADED:
*result = AP_MPMQ_STATIC;
break;
case AP_MPMQ_IS_FORKED:
*result = AP_MPMQ_DYNAMIC;
break;
case AP_MPMQ_IS_ASYNC:
*result = 1;
break;
case AP_MPMQ_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_WAITIO:
*result = 1;
break;
default:
*rv = APR_ENOTIMPL;
break;
}
return OK;
}
static void event_note_child_stopped(
int slot, pid_t pid, ap_generation_t gen)
{
if (slot != -1) {
/* child had a scoreboard slot? */
process_score *ps = &ap_scoreboard_image->parent[slot];
int i;
pid = ps->pid;
gen = ps->generation;
for (i = 0; i < threads_per_child; i++) {
ap_update_child_status_from_indexes(slot, i, SERVER_DEAD, NULL);
}
ap_run_child_status(ap_server_conf, pid, gen, slot, MPM_CHILD_EXITED);
if (ps->quiescing != 2) {
/* vs perform_idle_server_maintenance() */
retained->active_daemons--;
}
retained->total_daemons--;
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
"Child %d stopped: pid %d, gen %d, "
"active %d/%d, total %d/%d/%d, quiescing %d",
slot, (
int)pid, (
int)gen,
retained->active_daemons, active_daemons_limit,
retained->total_daemons, retained->max_daemon_used,
server_limit, ps->quiescing);
ps->not_accepting = 0;
ps->quiescing = 0;
ps->pid = 0;
}
else {
ap_run_child_status(ap_server_conf, pid, gen, -1, MPM_CHILD_EXITED);
}
}
static void event_note_child_started(
int slot, pid_t pid)
{
ap_generation_t gen = retained->mpm->my_generation;
retained->total_daemons++;
retained->active_daemons++;
ap_scoreboard_image->parent[slot].pid = pid;
ap_scoreboard_image->parent[slot].generation = gen;
ap_run_child_status(ap_server_conf, pid, gen, slot, MPM_CHILD_STARTED);
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
"Child %d started: pid %d, gen %d, "
"active %d/%d, total %d/%d/%d",
slot, (
int)pid, (
int)gen,
retained->active_daemons, active_daemons_limit,
retained->total_daemons, retained->max_daemon_used,
server_limit);
}
static const char *event_get_name(
void)
{
return "event";
}
/* a clean exit from a child with proper cleanup */
static void clean_child_exit(
int code) __attribute__ ((noreturn));
static void clean_child_exit(
int code)
{
retained->mpm->mpm_state = AP_MPMQ_STOPPING;
if (terminate_mode == ST_INIT) {
ap_run_child_stopping(pchild, 0);
}
if (pchild) {
apr_pool_destroy(pchild);
}
if (one_process) {
event_note_child_stopped(
/* slot */ 0, 0, 0);
}
exit(code);
}
static void just_die(
int sig)
{
clean_child_exit(0);
}
/*****************************************************************
* Connection structures and accounting...
*/
static int child_fatal;
static apr_status_t decrement_connection_count(
void *cs_)
{
int is_last_connection;
event_conn_state_t *cs = cs_;
ap_log_cerror(APLOG_MARK, APLOG_TRACE8, 0, cs->c,
"cleanup connection from state %i", (
int)cs->pub.state);
switch (cs->pub.state) {
case CONN_STATE_LINGER:
case CONN_STATE_LINGER_NORMAL:
case CONN_STATE_LINGER_SHORT:
apr_atomic_dec32(&lingering_count);
break;
case CONN_STATE_SUSPENDED:
apr_atomic_dec32(&suspended_count);
break;
default:
break;
}
/* Unblock the listener if it's waiting for connection_count = 0,
* or if the listening sockets were disabled due to limits and can
* now accept new connections.
*/
is_last_connection = !apr_atomic_dec32(&connection_count);
if (listener_is_wakeable
&& ((is_last_connection && listener_may_exit)
|| should_enable_listensocks())) {
apr_pollset_wakeup(event_pollset);
}
if (dying) {
/* Help worker_thread_should_exit_early() */
ap_queue_interrupt_one(worker_queue);
}
return APR_SUCCESS;
}
static void notify_suspend(event_conn_state_t *cs)
{
ap_run_suspend_connection(cs->c, cs->r);
cs->c->sbh = NULL;
cs->suspended = 1;
}
static void notify_resume(event_conn_state_t *cs,
int cleanup)
{
cs->suspended = 0;
cs->c->sbh = cleanup ? NULL : cs->sbh;
ap_run_resume_connection(cs->c, cs->r);
}
/*
* Defer flush and close of the connection by adding it to defer_linger_chain,
* for a worker to grab it and do the job (should that be blocking).
* Pre-condition: nonblocking, can be called from anywhere provided cs is not
* in any timeout queue or in the pollset.
*/
static int defer_lingering_close(event_conn_state_t *cs)
{
ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, cs->c,
"deferring close from state %i", (
int)cs->pub.state);
/* The connection is not shutdown() yet strictly speaking, but it's not
* in any queue nor handled by a worker either (will be very soon), so
* to account for it somewhere we bump lingering_count now (and set
* deferred_linger for process_lingering_close() to know).
*/
cs->pub.state = CONN_STATE_LINGER;
apr_atomic_inc32(&lingering_count);
cs->deferred_linger = 1;
for (;;) {
event_conn_state_t *chain = cs->chain = defer_linger_chain;
if (apr_atomic_casptr((
void *)&defer_linger_chain, cs,
chain) != chain) {
/* Race lost, try again */
continue;
}
return 1;
}
}
/* Close the connection and release its resources (ptrans), either because an
* unrecoverable error occured (queues or pollset add/remove) or more usually
* if lingering close timed out.
* Pre-condition: nonblocking, can be called from anywhere provided cs is not
* in any timeout queue or in the pollset.
*/
static void close_connection(event_conn_state_t *cs)
{
ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, cs->c,
"closing connection from state %i", (
int)cs->pub.state);
close_socket_nonblocking(cs->pfd.desc.s);
ap_queue_info_push_pool(worker_queue_info, cs->p);
}
/* Shutdown the connection in case of timeout, error or resources shortage.
* This starts short lingering close if not already there, or directly closes
* the connection otherwise.
* Pre-condition: nonblocking, can be called from anywhere provided cs is not
* in any timeout queue or in the pollset.
*/
static int shutdown_connection(event_conn_state_t *cs)
{
if (!CONN_STATE_IS_LINGERING_CLOSE(cs->pub.state)) {
apr_table_setn(cs->c->notes,
"short-lingering-close",
"1");
defer_lingering_close(cs);
}
else {
close_connection(cs);
}
return 1;
}
/*
* This runs before any non-MPM cleanup code on the connection;
* if the connection is currently suspended as far as modules
* know, provide notification of resumption.
*/
static apr_status_t ptrans_pre_cleanup(
void *dummy)
{
event_conn_state_t *cs = dummy;
if (cs->suspended) {
notify_resume(cs, 1);
}
return APR_SUCCESS;
}
/*
* event_pre_read_request() and event_request_cleanup() track the
* current r for a given connection.
*/
static apr_status_t event_request_cleanup(
void *dummy)
{
conn_rec *c = dummy;
event_conn_state_t *cs = ap_get_module_config(c->conn_config,
&mpm_event_module);
cs->r = NULL;
return APR_SUCCESS;
}
static void event_pre_read_request(request_rec *r, conn_rec *c)
{
event_conn_state_t *cs = ap_get_module_config(c->conn_config,
&mpm_event_module);
cs->r = r;
cs->sc = ap_get_module_config(ap_server_conf->module_config,
&mpm_event_module);
apr_pool_cleanup_register(r->pool, c, event_request_cleanup,
apr_pool_cleanup_null);
}
/*
* event_post_read_request() tracks the current server config for a
* given request.
*/
static int event_post_read_request(request_rec *r)
{
conn_rec *c = r->connection;
event_conn_state_t *cs = ap_get_module_config(c->conn_config,
&mpm_event_module);
/* To preserve legacy behaviour (consistent with other MPMs), use
* the keepalive timeout from the base server (first on this IP:port)
* when none is explicitly configured on this server.
*/
if (r->server->keep_alive_timeout_set) {
cs->sc = ap_get_module_config(r->server->module_config,
&mpm_event_module);
}
else {
cs->sc = ap_get_module_config(c->base_server->module_config,
&mpm_event_module);
}
return OK;
}
/* Forward declare */
static void process_lingering_close(event_conn_state_t *cs);
static void update_reqevents_from_sense(event_conn_state_t *cs,
int default_sense)
{
int sense = default_sense;
if (cs->pub.sense != CONN_SENSE_DEFAULT) {
sense = cs->pub.sense;
/* Reset to default for the next round */
cs->pub.sense = CONN_SENSE_DEFAULT;
}
if (sense == CONN_SENSE_WANT_READ) {
cs->pfd.reqevents = APR_POLLIN | APR_POLLHUP;
}
else {
cs->pfd.reqevents = APR_POLLOUT;
}
/* POLLERR is usually returned event only, but some pollset
* backends may require it in reqevents to do the right thing,
* so it shouldn't hurt (ignored otherwise).
*/
cs->pfd.reqevents |= APR_POLLERR;
}
/*
* process one connection in the worker
*/
static void process_socket(apr_thread_t *thd, apr_pool_t * p, apr_socket_t * sock,
event_conn_state_t * cs,
int my_child_num,
int my_thread_num)
{
conn_rec *c;
long conn_id = ID_FROM_CHILD_THREAD(my_child_num, my_thread_num);
int clogging = 0;
apr_status_t rv;
int rc = OK;
if (cs == NULL) {
/* This is a new connection */
listener_poll_type *pt = apr_pcalloc(p,
sizeof(*pt));
cs = apr_pcalloc(p,
sizeof(event_conn_state_t));
cs->bucket_alloc = apr_bucket_alloc_create(p);
ap_create_sb_handle(&cs->sbh, p, my_child_num, my_thread_num);
c = ap_run_create_connection(p, ap_server_conf, sock,
conn_id, cs->sbh, cs->bucket_alloc);
if (!c) {
ap_queue_info_push_pool(worker_queue_info, p);
return;
}
apr_atomic_inc32(&connection_count);
apr_pool_cleanup_register(c->pool, cs, decrement_connection_count,
apr_pool_cleanup_null);
ap_set_module_config(c->conn_config, &mpm_event_module, cs);
c->current_thread = thd;
c->cs = &cs->pub;
cs->c = c;
cs->p = p;
cs->sc = ap_get_module_config(ap_server_conf->module_config,
&mpm_event_module);
cs->pfd.desc_type = APR_POLL_SOCKET;
cs->pfd.desc.s = sock;
pt->type = PT_CSD;
pt->baton = cs;
cs->pfd.client_data = pt;
apr_pool_pre_cleanup_register(p, cs, ptrans_pre_cleanup);
TO_QUEUE_ELEM_INIT(cs);
ap_update_vhost_given_ip(c);
rc = ap_pre_connection(c, sock);
if (rc != OK && rc != DONE) {
ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, APLOGNO(00469)
"process_socket: connection aborted");
close_connection(cs);
return;
}
/**
* XXX If the platform does not have a usable way of bundling
* accept() with a socket readability check, like Win32,
* and there are measurable delays before the
* socket is readable due to the first data packet arriving,
* it might be better to create the cs on the listener thread
* with the state set to CONN_STATE_KEEPALIVE
*
* FreeBSD users will want to enable the HTTP accept filter
* module in their kernel for the highest performance
* When the accept filter is active, sockets are kept in the
* kernel until a HTTP request is received.
*/
cs->pub.state = CONN_STATE_PROCESSING;
cs->pub.sense = CONN_SENSE_DEFAULT;
}
else {
c = cs->c;
ap_update_sb_handle(cs->sbh, my_child_num, my_thread_num);
notify_resume(cs, 0);
c->current_thread = thd;
/* Subsequent request on a conn, and thread number is part of ID */
c->id = conn_id;
}
if (CONN_STATE_IS_LINGERING_CLOSE(cs->pub.state)) {
goto lingering_close;
}
if (cs->pub.state == CONN_STATE_PROCESSING
/* If we have an input filter which 'clogs' the input stream,
* like mod_ssl used to, lets just do the normal read from input
* filters, like the Worker MPM does. Filters that need to write
* where they would otherwise read, or read where they would
* otherwise write, should set the sense appropriately.
*/
|| c->clogging_input_filters) {
process_connection:
cs->pub.state = CONN_STATE_PROCESSING;
clogging = c->clogging_input_filters;
if (clogging) {
apr_atomic_inc32(&clogged_count);
}
rc = ap_run_process_connection(c);
if (clogging) {
apr_atomic_dec32(&clogged_count);
}
/*
* The process_connection hooks should set the appropriate connection
* state upon return, for event MPM to either:
* - CONN_STATE_LINGER: do lingering close;
* - CONN_STATE_WRITE_COMPLETION: flush pending outputs using Timeout
* and wait for next incoming data using KeepAliveTimeout, then come
* back to process_connection() hooks;
* - CONN_STATE_SUSPENDED: suspend the connection such that it now
* interacts with the MPM through suspend/resume_connection() hooks,
* and/or registered poll callbacks (PT_USER), and/or registered
* timed callbacks triggered by timer events;
* - CONN_STATE_ASYNC_WAITIO: wait for read/write-ability of the underlying
* socket using Timeout and come back to process_connection() hooks when
* ready;
* - CONN_STATE_KEEPALIVE: now handled by CONN_STATE_WRITE_COMPLETION
* to flush before waiting for next data (that might depend on it).
* If a process_connection hook returns an error or no hook sets the state
* to one of the above expected value, forcibly close the connection w/
* CONN_STATE_LINGER. This covers the cases where no process_connection
* hook executes (DECLINED), or one returns OK w/o touching the state (i.e.
* CONN_STATE_PROCESSING remains after the call) which can happen with
* third-party modules not updated to work specifically with event MPM
* while this was expected to do lingering close unconditionally with
* worker or prefork MPMs for instance.
*/
switch (rc) {
case DONE:
rc = OK;
/* same as OK, fall through */
case OK:
if (cs->pub.state == CONN_STATE_PROCESSING) {
cs->pub.state = CONN_STATE_LINGER;
}
else if (cs->pub.state == CONN_STATE_KEEPALIVE) {
cs->pub.state = CONN_STATE_WRITE_COMPLETION;
}
break;
}
if (rc != OK || (cs->pub.state != CONN_STATE_LINGER
&& cs->pub.state != CONN_STATE_ASYNC_WAITIO
&& cs->pub.state != CONN_STATE_WRITE_COMPLETION
&& cs->pub.state != CONN_STATE_SUSPENDED)) {
ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, APLOGNO(10111)
"process_socket: connection processing returned %i "
"(%sstate %i): closing",
rc, rc ?
"" :
"unexpected ", (
int)cs->pub.state);
cs->pub.state = CONN_STATE_LINGER;
}
else if (c->aborted) {
cs->pub.state = CONN_STATE_LINGER;
}
if (cs->pub.state == CONN_STATE_LINGER) {
goto lingering_close;
}
}
if (cs->pub.state == CONN_STATE_ASYNC_WAITIO) {
/* Set a read/write timeout for this connection, and let the
* event thread poll for read/writeability.
*/
cs->queue_timestamp = apr_time_now();
notify_suspend(cs);
ap_update_child_status(cs->sbh, SERVER_BUSY_READ, NULL);
/* Modules might set c->cs->sense to CONN_SENSE_WANT_WRITE,
* the default is CONN_SENSE_WANT_READ still.
*/
update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ);
apr_thread_mutex_lock(timeout_mutex);
TO_QUEUE_APPEND(cs->sc->io_q, cs);
rv = apr_pollset_add(event_pollset, &cs->pfd);
if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) {
AP_DEBUG_ASSERT(0);
TO_QUEUE_REMOVE(cs->sc->io_q, cs);
apr_thread_mutex_unlock(timeout_mutex);
ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(10503)
"process_socket: apr_pollset_add failure in "
"CONN_STATE_ASYNC_WAITIO");
close_connection(cs);
signal_threads(ST_GRACEFUL);
}
else {
apr_thread_mutex_unlock(timeout_mutex);
}
return;
}
if (cs->pub.state == CONN_STATE_WRITE_COMPLETION) {
ap_filter_t *output_filter = c->output_filters;
apr_status_t rv;
/* Flush all pending outputs before going to CONN_STATE_KEEPALIVE or
* straight to CONN_STATE_PROCESSING if inputs are pending already.
*/
ap_update_child_status(cs->sbh, SERVER_BUSY_WRITE, NULL);
while (output_filter->next != NULL) {
output_filter = output_filter->next;
}
rv = output_filter->frec->filter_func.out_func(output_filter, NULL);
if (rv != APR_SUCCESS) {
ap_log_cerror(APLOG_MARK, APLOG_DEBUG, rv, c, APLOGNO(00470)
"network write failure in core output filter");
cs->pub.state = CONN_STATE_LINGER;
goto lingering_close;
}
if (c->data_in_output_filters || 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);
/* Add work to pollset. */
update_reqevents_from_sense(cs, CONN_SENSE_WANT_WRITE);
apr_thread_mutex_lock(timeout_mutex);
TO_QUEUE_APPEND(cs->sc->wc_q, cs);
rv = apr_pollset_add(event_pollset, &cs->pfd);
if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) {
AP_DEBUG_ASSERT(0);
TO_QUEUE_REMOVE(cs->sc->wc_q, cs);
apr_thread_mutex_unlock(timeout_mutex);
ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03465)
"process_socket: apr_pollset_add failure in "
"CONN_STATE_WRITE_COMPLETION");
close_connection(cs);
signal_threads(ST_GRACEFUL);
}
else {
apr_thread_mutex_unlock(timeout_mutex);
}
return;
}
if (c->keepalive != AP_CONN_KEEPALIVE || c->aborted) {
cs->pub.state = CONN_STATE_LINGER;
goto lingering_close;
}
if (c->data_in_input_filters) {
goto process_connection;
}
if (listener_may_exit) {
cs->pub.state = CONN_STATE_LINGER;
goto lingering_close;
}
/* Fall through */
cs->pub.state = CONN_STATE_KEEPALIVE;
}
if (cs->pub.state == CONN_STATE_KEEPALIVE) {
ap_update_child_status(cs->sbh, SERVER_BUSY_KEEPALIVE, NULL);
/* It greatly simplifies the logic to use a single timeout value per q
* because the new element can just be added to the end of the list and
* it will stay sorted in expiration time sequence. If brand new
* sockets are sent to the event thread for a readability check, this
* will be a slight behavior change - they use the non-keepalive
* timeout today. With a normal client, the socket will be readable in
* a few milliseconds anyway.
*/
cs->queue_timestamp = apr_time_now();
notify_suspend(cs);
/* Add work to pollset. */
cs->pub.sense = CONN_SENSE_DEFAULT;
update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ);
apr_thread_mutex_lock(timeout_mutex);
TO_QUEUE_APPEND(cs->sc->ka_q, cs);
rv = apr_pollset_add(event_pollset, &cs->pfd);
if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) {
AP_DEBUG_ASSERT(0);
TO_QUEUE_REMOVE(cs->sc->ka_q, cs);
apr_thread_mutex_unlock(timeout_mutex);
ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03093)
"process_socket: apr_pollset_add failure for "
"keep alive");
close_connection(cs);
signal_threads(ST_GRACEFUL);
}
else {
apr_thread_mutex_unlock(timeout_mutex);
}
return;
}
if (cs->pub.state == CONN_STATE_SUSPENDED) {
apr_atomic_inc32(&suspended_count);
notify_suspend(cs);
return;
}
lingering_close:
/* CONN_STATE_LINGER[_*] fall through process_lingering_close() */
process_lingering_close(cs);
}
/* conns_this_child has gone to zero or below. See if the admin coded
"MaxConnectionsPerChild 0", and keep going in that case. Doing it this way
simplifies the hot path in worker_thread */
static void check_infinite_requests(
void)
{
if (ap_max_requests_per_child) {
ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
"Stopping process due to MaxConnectionsPerChild");
signal_threads(ST_GRACEFUL);
}
/* 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.
*/
}
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 apr_status_t event_register_timed_callback(apr_time_t t,
ap_mpm_callback_fn_t *cbfn,
void *baton)
{
timer_event_t *te;
/* oh yeah, and make locking smarter/fine grained. */
apr_thread_mutex_lock(g_timer_skiplist_mtx);
if (!APR_RING_EMPTY(&timer_free_ring.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;
/* XXXXX: optimize */
te->when = t + apr_time_now();
{
apr_time_t next_expiry;
/* Okay, add sorted by when.. */
apr_skiplist_insert(timer_skiplist, te);
/* Cheaply update the 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 APR_SUCCESS;
}
/*
* Flush data and close our side of the connection, then drain incoming data.
* If the latter would block put the connection in one of the linger timeout
* queues to be called back when ready, and repeat until it's closed by peer.
* Only to be called in the worker thread, and since it's in immediate call
* stack, we can afford a comfortable buffer size to consume data quickly.
* Pre-condition: cs is not in any timeout queue and not in the pollset,
* timeout_mutex is not locked
*/
#define LINGERING_BUF_SIZE (32 * 1024)
static void process_lingering_close(event_conn_state_t *cs)
{
apr_socket_t *csd = ap_get_conn_socket(cs->c);
char dummybuf[LINGERING_BUF_SIZE];
apr_size_t nbytes;
apr_status_t rv;
struct timeout_queue *q;
ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, cs->c,
"lingering close from state %i", (
int)cs->pub.state);
AP_DEBUG_ASSERT(CONN_STATE_IS_LINGERING_CLOSE(cs->pub.state));
if (!cs->linger_started) {
cs->pub.state = CONN_STATE_LINGER;
cs->linger_started = 1;
/* defer_lingering_close() may have bumped lingering_count already */
if (!cs->deferred_linger) {
apr_atomic_inc32(&lingering_count);
}
apr_socket_timeout_set(csd, apr_time_from_sec(SECONDS_TO_LINGER));
if (ap_start_lingering_close(cs->c)) {
notify_suspend(cs);
close_connection(cs);
return;
}
/* All nonblocking from now, no need for APR_INCOMPLETE_READ either */
apr_socket_timeout_set(csd, 0);
apr_socket_opt_set(csd, APR_INCOMPLETE_READ, 0);
/*
* If some module requested a shortened waiting period, only wait for
* 2s (SECONDS_TO_LINGER). This is useful for mitigating certain
* DoS attacks.
*/
if (apr_table_get(cs->c->notes,
"short-lingering-close")) {
cs->pub.state = CONN_STATE_LINGER_SHORT;
}
else {
cs->pub.state = CONN_STATE_LINGER_NORMAL;
}
cs->pub.sense = CONN_SENSE_DEFAULT;
notify_suspend(cs);
/* One timestamp/duration for the whole lingering close time.
* XXX: This makes the (short_)linger_q not sorted/ordered by expiring
* timeouts whenever multiple schedules are necessary (EAGAIN below),
* but we probabaly don't care since these connections do not count
* for connections_above_limit() and all of them will be killed when
* busy or gracefully stopping anyway.
*/
cs->queue_timestamp = apr_time_now();
}
do {
nbytes =
sizeof(dummybuf);
rv = apr_socket_recv(csd, dummybuf, &nbytes);
}
while (rv == APR_SUCCESS);
if (!APR_STATUS_IS_EAGAIN(rv)) {
close_connection(cs);
return;
}
/* (Re)queue the connection to come back when readable */
update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ);
q = (cs->pub.state == CONN_STATE_LINGER_SHORT) ? short_linger_q : linger_q;
apr_thread_mutex_lock(timeout_mutex);
TO_QUEUE_APPEND(q, cs);
rv = apr_pollset_add(event_pollset, &cs->pfd);
if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) {
AP_DEBUG_ASSERT(0);
TO_QUEUE_REMOVE(q, cs);
apr_thread_mutex_unlock(timeout_mutex);
ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03092)
"process_lingering_close: apr_pollset_add failure");
close_connection(cs);
signal_threads(ST_GRACEFUL);
return;
}
apr_thread_mutex_unlock(timeout_mutex);
}
/* call 'func' for all elements of 'q' above 'expiry'.
* Pre-condition: timeout_mutex must already be locked
* Post-condition: timeout_mutex will be locked again
*/
static void process_timeout_queue(
struct timeout_queue *q, apr_time_t expiry,
int (*func)(event_conn_state_t *))
{
apr_uint32_t total = 0, count;
event_conn_state_t *first, *cs, *last;
struct event_conn_state_t trash;
struct timeout_queue *qp;
apr_status_t rv;
if (!*q->total) {
return;
}
APR_RING_INIT(&trash.timeout_list, event_conn_state_t, timeout_list);
for (qp = q; qp; qp = qp->next) {
count = 0;
cs = first = last = APR_RING_FIRST(&qp->head);
while (cs != APR_RING_SENTINEL(&qp->head, event_conn_state_t,
timeout_list)) {
/* Trash the entry if:
* - no expiry was given (zero means all), or
* - it expired (according to the queue timeout), or
* - the system clock skewed in the past: no entry should be
* registered above the given expiry (~now) + the queue
* timeout, we won't keep any here (eg. for centuries).
*
* Otherwise stop, no following entry will match thanks to the
* single timeout per queue (entries are added to the end!).
* This allows maintenance in O(1).
*/
if (expiry && cs->queue_timestamp + qp->timeout > expiry
&& cs->queue_timestamp < expiry + qp->timeout) {
/* Since this is the next expiring entry of this queue, update
* the global queues_next_expiry if it's later than this one.
*/
apr_time_t elem_expiry = cs->queue_timestamp + qp->timeout;
apr_time_t next_expiry = queues_next_expiry;
if (!next_expiry
|| next_expiry > elem_expiry + TIMEOUT_FUDGE_FACTOR) {
queues_next_expiry = elem_expiry;
}
break;
}
last = cs;
rv = apr_pollset_remove(event_pollset, &cs->pfd);
if (rv != APR_SUCCESS && !APR_STATUS_IS_NOTFOUND(rv)) {
AP_DEBUG_ASSERT(0);
ap_log_cerror(APLOG_MARK, APLOG_ERR, rv, cs->c, APLOGNO(00473)
"apr_pollset_remove failed");
}
cs = APR_RING_NEXT(cs, timeout_list);
count++;
}
if (!count)
continue;
APR_RING_UNSPLICE(first, last, timeout_list);
APR_RING_SPLICE_TAIL(&trash.timeout_list, first, last, event_conn_state_t,
timeout_list);
AP_DEBUG_ASSERT(*q->total >= count && qp->count >= count);
*q->total -= count;
qp->count -= count;
total += count;
}
if (!total)
return;
apr_thread_mutex_unlock(timeout_mutex);
first = APR_RING_FIRST(&trash.timeout_list);
do {
cs = APR_RING_NEXT(first, timeout_list);
TO_QUEUE_ELEM_INIT(first);
func(first);
first = cs;
}
while (--total);
apr_thread_mutex_lock(timeout_mutex);
}
static void process_keepalive_queue(apr_time_t expiry)
{
/* If all workers are busy, we kill older keep-alive connections so
* that they may connect to another process.
*/
if (!expiry && *keepalive_q->total) {
ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
"All workers are busy or dying, will shutdown %u "
"keep-alive connections", *keepalive_q->total);
}
process_timeout_queue(keepalive_q, expiry, shutdown_connection);
}
static void * APR_THREAD_FUNC listener_thread(apr_thread_t * thd,
void *dummy)
{
apr_status_t rc;
proc_info *ti = dummy;
int process_slot = ti->pslot;
struct process_score *ps = ap_get_scoreboard_process(process_slot);
int closed = 0;
int have_idle_worker = 0;
apr_time_t last_log;
last_log = apr_time_now();
free(ti);
/* 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;
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 */
}
}
now = apr_time_now();
if (APLOGtrace6(ap_server_conf)) {
/* trace log status every second */
if (now - last_log > apr_time_from_sec(1)) {
ap_log_error(APLOG_MARK, APLOG_TRACE6, 0, ap_server_conf,
"connections: %u (waitio:%u write-completion:%u"
"keep-alive:%u lingering:%u suspended:%u clogged:%u), "
"workers: %u/%u shutdown",
apr_atomic_read32(&connection_count),
apr_atomic_read32(waitio_q->total),
apr_atomic_read32(write_completion_q->total),
apr_atomic_read32(keepalive_q->total),
apr_atomic_read32(&lingering_count),
apr_atomic_read32(&suspended_count),
apr_atomic_read32(&clogged_count),
apr_atomic_read32(&threads_shutdown),
threads_per_child);
last_log = now;
}
}
/* 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);
push_timer2worker(te);
}
if (!te) {
timers_next_expiry = 0;
}
apr_thread_mutex_unlock(g_timer_skiplist_mtx);
}
/* Same for queues, use their next expiry, if any. */
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,
"apr_pollset_poll failed. Attempting to "
"shutdown process gracefully");
signal_threads(ST_GRACEFUL);
}
num = 0;
--> --------------------
--> maximum size reached
--> --------------------
