event.c revision 4bd465052c4a0c8d41e573ee7a90c312d980355f
/* 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
*
*
* 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
* signifigant overhead in creating TCP connections. However, the major
* disadvantage is that Apache traditionally keeps an entire child
* this MPM has a dedicated thread for handling both the Listenting sockets,
* and all sockets that are in a Keep Alive status.
*
* The MPM assumes the underlying apr_pollset implmentation 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 not preform 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_proc_mutex.h"
#include "apr_poll.h"
#include "apr_ring.h"
#include "apr_queue.h"
#define APR_WANT_STRFUNC
#include "apr_want.h"
#include <unistd.h>
#endif
#endif
#endif
#ifdef HAVE_SYS_PROCESSOR_H
#endif
#if !APR_HAS_THREADS
#endif
#define CORE_PRIVATE
#include "ap_config.h"
#include "httpd.h"
#include "http_main.h"
#include "http_log.h"
#include "http_config.h" /* for read_config */
#include "http_core.h" /* for get_remote_host */
#include "http_connection.h"
#include "ap_mpm.h"
#include "pod.h"
#include "mpm_common.h"
#include "ap_listen.h"
#include "scoreboard.h"
#include "fdqueue.h"
#include "mpm_default.h"
#include "http_vhost.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
/*
* Actual definitions of config globals
*/
int ap_threads_per_child = 0; /* Worker threads per child */
static int ap_daemons_to_start = 0;
static int min_spare_threads = 0;
static int max_spare_threads = 0;
static int ap_daemons_limit = 0;
static int max_clients = 0;
static int server_limit = 0;
static int first_server_limit = 0;
static int thread_limit = 0;
static int first_thread_limit = 0;
static int dying = 0;
static int workers_may_exit = 0;
static int start_thread_may_exit = 0;
static int listener_may_exit = 0;
static int requests_this_child;
static int num_listensocks = 0;
static int resource_shortage = 0;
static fd_queue_t *worker_queue;
static fd_queue_info_t *worker_queue_info;
static int mpm_state = AP_MPMQ_STARTING;
static int sick_child_detected;
static apr_pollset_t *event_pollset;
/* The structure used to pass unique initialization info to each thread */
typedef struct
{
int pid;
int tid;
int sd;
} proc_info;
/* Structure used to pass information to the thread responsible for
* creating the rest of the threads.
*/
typedef struct
{
int child_num_arg;
typedef enum
{
} poll_type_e;
typedef struct
{
int status; /*XXX what is this for? 0 and 1 don't make it clear */
void *baton;
#define ID_FROM_CHILD_THREAD(c, t) ((c * thread_limit) + t)
/*
* The max child slot ever assigned, preserved across restarts. Necessary
* to deal with MaxClients changes across AP_SIG_GRACEFUL restarts. We
* use this value to optimize routines that have to scan the entire
* scoreboard.
*/
int ap_max_daemons_limit = -1;
/* *Non*-shared http_main globals... */
/* The worker MPM respects a couple of runtime flags that can aid
* in debugging. Setting the -DNO_DETACH flag will prevent the root process
* from detaching from its controlling terminal. Additionally, setting
* the -DONE_PROCESS flag (which implies -DNO_DETACH) will get you the
* child_main loop running in the process which originally started up.
* This gives you a pretty nice debugging environment. (You'll get a SIGHUP
* early in standalone_main; just continue through. This is the server
* trying to kill off any child processes which it might have lying
* around --- Apache doesn't keep track of their pids, it just sends
* SIGHUP to the process group, ignoring it in the root process.
* Continue through and you'll be fine.).
*/
static int one_process = 0;
#ifdef DEBUG_SIGSTOP
int raise_sigstop_flags;
#endif
thread. Use this instead */
static pid_t parent_pid;
static apr_os_thread_t *listener_os_thread;
/* 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 void close_worker_sockets(void)
{
int i;
for (i = 0; i < ap_threads_per_child; i++) {
if (worker_sockets[i]) {
worker_sockets[i] = NULL;
}
}
}
static void wakeup_listener(void)
{
listener_may_exit = 1;
if (!listener_os_thread) {
/* XXX there is an obscure path that this doesn't handle perfectly:
* right after listener thread is created but before
* listener_os_thread is set, the first worker thread hits an
* error and starts graceful termination
*/
return;
}
/*
* we should just be able to "kill(ap_my_pid, LISTENER_SIGNAL)" on all
* platforms and wake up the listener thread since it is the only thread
* with SIGHUP unblocked, but that doesn't work on Linux
*/
#ifdef HAVE_PTHREAD_KILL
#else
#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;
}
/* in case we weren't called from the listener thread, wake up the
* listener thread
*/
/* 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;
close_worker_sockets(); /* forcefully kill all current connections */
}
}
{
switch (query_code) {
case AP_MPMQ_MAX_DAEMON_USED:
return APR_SUCCESS;
case AP_MPMQ_IS_THREADED:
*result = AP_MPMQ_STATIC;
return APR_SUCCESS;
case AP_MPMQ_IS_FORKED:
return APR_SUCCESS;
case AP_MPMQ_IS_ASYNC:
*result = 1;
return APR_SUCCESS;
*result = server_limit;
return APR_SUCCESS;
*result = thread_limit;
return APR_SUCCESS;
case AP_MPMQ_MAX_THREADS:
return APR_SUCCESS;
*result = 0;
return APR_SUCCESS;
return APR_SUCCESS;
*result = 0;
return APR_SUCCESS;
return APR_SUCCESS;
return APR_SUCCESS;
case AP_MPMQ_MAX_DAEMONS:
return APR_SUCCESS;
case AP_MPMQ_MPM_STATE:
return APR_SUCCESS;
}
return APR_ENOTIMPL;
}
/* a clean exit from a child with proper cleanup */
static void clean_child_exit(int code)
{
if (pchild) {
}
}
{
clean_child_exit(0);
}
/*****************************************************************
* Connection structures and accounting...
*/
/* volatile just in case */
static int volatile shutdown_pending;
static int volatile restart_pending;
static int volatile is_graceful;
static volatile int child_fatal;
ap_generation_t volatile ap_my_generation = 0;
/*
* ap_start_shutdown() and ap_start_restart(), below, are a first stab at
* functions to initiate shutdown or restart without relying on signals.
* Previously this was initiated in sig_term() and restart() signal handlers,
* e.g. on Win32, from the service manager. Now the service manager can
* call ap_start_shutdown() or ap_start_restart() as appropiate. Note that
* these functions can also be called by the child processes, since global
* variables are no longer used to pass on the required action to the parent.
*
* These should only be called from the parent process itself, since the
* parent process will use the shutdown_pending and restart_pending variables
* to determine whether to shutdown or restart. The child process should
* call signal_parent() directly to tell the parent to die -- this will
* cause neither of those variable to be set, which the parent will
* assume means something serious is wrong (which it will be, for the
* child to force an exit) and so do an exit anyway.
*/
static void ap_start_shutdown(int graceful)
{
if (shutdown_pending == 1) {
/* Um, is this _probably_ not an error, if the user has
* tried to do a shutdown twice quickly, so we won't
* worry about reporting it.
*/
return;
}
shutdown_pending = 1;
}
/* do a graceful restart if graceful == 1 */
static void ap_start_restart(int graceful)
{
if (restart_pending == 1) {
/* Probably not an error - don't bother reporting it */
return;
}
restart_pending = 1;
}
{
}
{
}
static void set_signals(void)
{
#ifndef NO_USE_SIGACTION
#endif
if (!one_process) {
}
#ifndef NO_USE_SIGACTION
"sigaction(SIGTERM)");
#ifdef AP_SIG_GRACEFUL_STOP
#endif
#ifdef SIGINT
"sigaction(SIGINT)");
#endif
#ifdef SIGXCPU
"sigaction(SIGXCPU)");
#endif
#ifdef SIGXFSZ
"sigaction(SIGXFSZ)");
#endif
#ifdef SIGPIPE
"sigaction(SIGPIPE)");
#endif
/* we want to ignore HUPs and AP_SIG_GRACEFUL while we're busy
* processing one */
"sigaction(SIGHUP)");
#else
if (!one_process) {
#ifdef SIGXCPU
#endif /* SIGXCPU */
#ifdef SIGXFSZ
#endif /* SIGXFSZ */
}
#ifdef SIGHUP
#endif /* SIGHUP */
#ifdef AP_SIG_GRACEFUL
#endif /* AP_SIG_GRACEFUL */
#ifdef AP_SIG_GRACEFUL_STOP
#endif /* AP_SIG_GRACEFUL_STOP */
#ifdef SIGPIPE
#endif /* SIGPIPE */
#endif
}
/*****************************************************************
* Here follows a long bunch of generic server bookkeeping stuff...
*/
int ap_graceful_stop_signalled(void)
/* XXX this is really a bad confusing obsolete name
* maybe it should be ap_mpm_process_exiting?
*/
{
/* note: for a graceful termination, listener_may_exit will be set before
* workers_may_exit, so check listener_may_exit
*/
return listener_may_exit;
}
/*****************************************************************
* Child process main loop.
*/
int my_thread_num)
{
conn_rec *c;
int csd;
int rc;
cs->c = c;
cs->p = p;
"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.
*/
}
else {
c = cs->c;
}
if (!c->aborted) {
/* state will be updated upon return
* fall thru to either wait for readability/timeout or
* do lingering close
*/
}
else {
}
}
}
if (rv != APR_SUCCESS) {
"network write failure in core output filter");
}
else if (c->data_in_output_filters) {
/* Still in WRITE_COMPLETION_STATE:
* Set a write timeout for this connection, and let the
* event thread poll for writeability.
*/
return 1;
}
}
else if (c->data_in_input_filters) {
goto read_request;
}
else {
}
}
apr_pool_clear(p);
return 1;
}
/* It greatly simplifies the logic to use a single timeout value here
* 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.
*/
apr_time_now();
/* Add work to pollset. */
if (rc != APR_SUCCESS) {
"process_socket: apr_pollset_add failure");
}
}
return 0;
}
/* requests_this_child has gone to zero or below. See if the admin coded
"MaxRequestsPerChild 0", and keep going in that case. Doing it this way
simplifies the hot path in worker_thread */
static void check_infinite_requests(void)
{
if (ap_max_requests_per_child) {
}
else {
/* wow! if you're executing this code, you may have set a record.
* either this child process has served over 2 billion requests, or
* you're running a threaded 2.0 on a 16 bit machine.
*
* I'll buy pizza and beers at Apachecon for the first person to do
* the former without cheating (dorking with INT_MAX, or running with
* uncommitted performance patches, for example).
*
* for the latter case, you probably deserve a beer too. Greg Ames
*/
}
}
static void unblock_signal(int sig)
{
#if defined(SIGPROCMASK_SETS_THREAD_MASK)
#else
#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 (rv != APR_SUCCESS) {
"creation of the timeout mutex failed.");
return rv;
}
/* Create the main pollset */
if (rv != APR_SUCCESS) {
"apr_pollset_create with Thread Safety failed.");
return rv;
}
}
return APR_SUCCESS;
}
{
return 0;
}
/*
* 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) {
/* trash the connection; we couldn't queue the connected
* socket to a worker
*/
ap_server_conf, "push2worker: ap_queue_push failed");
apr_pool_clear(cs->p);
}
return APR_SUCCESS;
}
/* get_worker:
* reserve a worker thread, block if all are currently busy.
* this prevents the worker queue from overflowing and lets
* other processes accept new connections in the mean time.
*/
static int get_worker(int *have_idle_worker_p)
{
if (!*have_idle_worker_p) {
if (rc == APR_SUCCESS) {
*have_idle_worker_p = 1;
return 1;
}
else {
if (!APR_STATUS_IS_EOF(rc)) {
"ap_queue_info_wait_for_idler failed. "
"Attempting to shutdown process gracefully");
}
return 0;
}
}
else {
/* already reserved a worker thread - must have hit a
* transient error on a previous pass
*/
return 1;
}
}
{
int have_idle_worker = 0;
const apr_pollfd_t *out_pfd;
apr_int32_t num = 0;
apr_time_t time_now = 0;
/* We set this to force apr_pollset to wakeup if there hasn't been any IO
* on any of its sockets. This allows sockets to have been added
* when no other keepalive operations where going on.
*
* current value is 1 second
*/
timeout_interval = 1000000;
/* the following times out events that are really close in the future
* to prevent extra poll calls
*
* current value is .1 second
*/
#define TIMEOUT_FUDGE_FACTOR 100000
if (rc != APR_SUCCESS) {
"failed to initialize pollset, "
"attempting to shutdown process gracefully");
return NULL;
}
/* Unblock the signal used to wake this thread up, and set a handler for
* it.
*/
while (!listener_may_exit) {
if (requests_this_child <= 0) {
}
&out_pfd);
if (rc != APR_SUCCESS) {
if (APR_STATUS_IS_EINTR(rc)) {
continue;
}
if (!APR_STATUS_IS_TIMEUP(rc)) {
"apr_pollset_poll failed. Attempting to "
"shutdown process gracefully");
}
}
if (listener_may_exit)
break;
/* one of the sockets is readable */
break;
break;
default:
"event_loop: unexpected state %d",
AP_DEBUG_ASSERT(0);
}
if (rc != APR_SUCCESS) {
ap_server_conf, "push2worker failed");
}
else {
have_idle_worker = 0;
}
}
else {
/* A Listener Socket is ready for an accept() */
/* create a new transaction pool for each accepted socket */
"Failed to create transaction pool");
return NULL;
}
}
/* later we trash rv and rely on csd to indicate
*/
if (rc == APR_EGENERAL) {
/* E[NM]FILE, ENOMEM, etc */
resource_shortage = 1;
}
if (rc != APR_SUCCESS) {
/* trash the connection; we couldn't queue the connected
* socket to a worker
*/
"ap_queue_push failed");
}
else {
have_idle_worker = 0;
}
}
else {
}
} /* if:else on pt->type */
out_pfd++;
num--;
} /* while for processing poll */
/* XXX possible optimization: stash the current time for use as
* r->request_time for new requests
*/
time_now = apr_time_now();
/* handle timed out sockets */
/* Step 1: keepalive timeouts */
&& get_worker(&have_idle_worker)) {
if (rc != APR_SUCCESS) {
return NULL;
/* XXX return NULL looks wrong - not an init failure
* that bypasses all the cleanup outside the main loop
* break seems more like it
* need to evaluate seriousness of push2worker failures
*/
}
have_idle_worker = 0;
}
/* Step 2: write completion timeouts */
&& get_worker(&have_idle_worker)) {
if (rc != APR_SUCCESS) {
return NULL;
}
have_idle_worker = 0;
}
} /* listener main loop */
dying = 1;
/* wake up the main thread */
return NULL;
}
/* XXX For ungraceful termination/restart, we definitely don't want to
* wait for active connections to finish but we may want to wait
* for idle workers to get out of the queue code and release mutexes,
* since those mutexes are cleaned up pretty soon and some systems
* may not react favorably (i.e., segfault) if operations are attempted
* on cleaned-up mutexes.
*/
{
int is_idle = 0;
while (!workers_may_exit) {
if (!is_idle) {
if (rv != APR_SUCCESS) {
"ap_queue_info_set_idle failed. Attempting to "
"shutdown process gracefully.");
break;
}
is_idle = 1;
}
SERVER_READY, NULL);
if (workers_may_exit) {
break;
}
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_queue_pop failed");
}
continue;
}
is_idle = 0;
if (!rv) {
}
}
(dying) ? SERVER_DEAD :
(request_rec *) NULL);
return NULL;
}
static int check_signal(int signum)
{
switch (signum) {
case SIGTERM:
case SIGINT:
return 1;
}
return 0;
}
{
if (rv != APR_SUCCESS) {
"apr_thread_create: unable to create listener thread");
/* let the parent decide how bad this really is */
}
}
/* 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
*/
{
int my_child_num = child_num_arg;
int i;
int threads_created = 0;
int listener_started = 0;
int loops;
int prev_threads_created;
/* We must create the fd queues before we start up the listener
* and worker threads. */
if (rv != APR_SUCCESS) {
"ap_queue_init() failed");
}
if (rv != APR_SUCCESS) {
"ap_queue_info_create() failed");
}
* sizeof(apr_socket_t *));
loops = prev_threads_created = 0;
while (1) {
/* ap_threads_per_child does not include the listener thread */
for (i = 0; i < ap_threads_per_child; i++) {
int status =
continue;
}
"malloc: out of memory");
}
/* We are creating threads right now */
/* We let each thread update its own scoreboard entry. This is
* done because it lets us deal with tid better.
*/
if (rv != APR_SUCCESS) {
"apr_thread_create: unable to create worker thread");
/* let the parent decide how bad this really is */
}
}
/* Start the listener only when there are workers available */
if (!listener_started && threads_created) {
listener_started = 1;
}
break;
}
/* wait for previous generation to clean up an entry */
++loops;
if (prev_threads_created == threads_created) {
"slots very quickly (%d of %d)",
}
}
}
/* 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
*/
return NULL;
}
{
int i;
if (listener) {
int iter;
/* deal with a rare timing window which affects waking up the
* listener thread... if the signal sent to the listener thread
* is delivered between the time it verifies that the
* listener_may_exit flag is clear and the time it enters a
* blocking syscall, the signal didn't do any good... work around
* that by sleeping briefly and sending it again
*/
iter = 0;
while (iter < 10 &&
#ifdef HAVE_PTHREAD_KILL
#else
#endif
== 0) {
/* listener not dead yet */
++iter;
}
if (iter >= 10) {
"the listener thread didn't exit");
}
else {
if (rv != APR_SUCCESS) {
"apr_thread_join: unable to join listener thread");
}
}
}
for (i = 0; i < ap_threads_per_child; i++) {
if (threads[i]) { /* if we ever created this thread */
if (rv != APR_SUCCESS) {
"apr_thread_join: unable to join worker "
"thread %d", i);
}
}
}
}
{
* trying to take over slots from a
* previous generation
*/
if (rv != APR_SUCCESS) {
"apr_thread_join: unable to join the start " "thread");
}
}
static void child_main(int child_num_arg)
{
* child initializes
*/
/*stuff to do before we switch id's, so we have permissions. */
if (unixd_setup_child()) {
}
/* done with init critical section */
/* Just use the standard apr_setup_signal_thread to block all signals
* from being received. The child processes no longer use signals for
* any communication with the parent process.
*/
if (rv != APR_SUCCESS) {
"Couldn't initialize signal thread");
}
if (ap_max_requests_per_child) {
}
else {
/* coding a value of zero means infinity */
}
/* Setup worker threads */
/* clear the storage; we may not create all our threads immediately,
* and we want a 0 entry to indicate a thread which was not created
*/
sizeof(apr_thread_t *) *
"malloc: out of memory");
}
/* 0 means PTHREAD_CREATE_JOINABLE */
if (ap_thread_stacksize != 0) {
}
if (rv != APR_SUCCESS) {
"apr_thread_create: unable to create worker thread");
/* let the parent decide how bad this really is */
}
/* 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. */
/* 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
*/
/* helps us terminate a little more quickly than the dispatch of the
* signal thread; beats the Pipe of Death and the browsers
*/
/* A terminating signal was received. Now join each of the
* workers to clean them up.
* If the worker already exited, then the join frees
* their resources and returns.
* If the worker hasn't exited, then this blocks until
* they have (then cleans up).
*/
}
else { /* !one_process */
/* remove SIGTERM from the set of blocked signals... if one of
* the other threads in the process needs to take us down
* (e.g., for MaxRequestsPerChild) it will send us SIGTERM
*/
/* Watch for any messages from the parent over the POD */
while (1) {
if (rv == AP_NORESTART) {
/* see if termination was triggered while we slept */
switch (terminate_mode) {
case ST_GRACEFUL:
rv = AP_GRACEFUL;
break;
case ST_UNGRACEFUL:
rv = AP_RESTART;
break;
}
}
/* make sure the start thread has finished;
* signal_threads() and join_workers depend on that
*/
signal_threads(rv ==
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).
*/
}
}
{
int pid;
}
if (one_process) {
set_signals();
}
"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. */
return -1;
}
if (!pid) {
#ifdef HAVE_BINDPROCESSOR
/* By default, AIX binds to a single processor. This bit unbinds
* children which will then bind to another CPU.
*/
"processor unbind failed %d", status);
#endif
clean_child_exit(0);
}
/* else */
return 0;
}
/* start up a bunch of children */
static void startup_children(int number_to_start)
{
int i;
for (i = 0; number_to_start && i < ap_daemons_limit; ++i) {
continue;
}
if (make_child(ap_server_conf, i) < 0) {
break;
}
}
}
/*
* idle_spawn_rate is the number of children that will be spawned on the
* next maintenance cycle if there aren't enough idle servers. It is
* doubled up to MAX_SPAWN_RATE, and reset only when a cycle goes by
* without the need to spawn.
*/
static int idle_spawn_rate = 1;
#ifndef MAX_SPAWN_RATE
#define MAX_SPAWN_RATE (32)
#endif
static int hold_off_on_exponential_spawning;
static void perform_idle_server_maintenance(void)
{
int i, j;
int idle_thread_count;
int free_length;
int totally_free_length = 0;
int free_slots[MAX_SPAWN_RATE];
int last_non_dead;
int total_non_dead;
int active_thread_count = 0;
/* initialize the free_list */
free_length = 0;
idle_thread_count = 0;
last_non_dead = -1;
total_non_dead = 0;
for (i = 0; i < ap_daemons_limit; ++i) {
/* Initialization to satisfy the compiler. It doesn't know
* that ap_threads_per_child is always > 0 */
int status = SERVER_DEAD;
int any_dying_threads = 0;
int any_dead_threads = 0;
int all_dead_threads = 1;
if (i >= ap_max_daemons_limit
/* short cut if all active processes have been examined and
* enough empty scoreboard slots have been found
*/
break;
for (j = 0; j < ap_threads_per_child; j++) {
/* XXX any_dying_threads is probably no longer needed GLA */
(status == SERVER_GRACEFUL);
/* We consider a starting server as idle because we started it
* at least a cycle ago, and if it still hasn't finished starting
* then we're just going to swamp things worse by forking more.
* So we hopefully won't need to fork more if we count it.
* This depends on the ordering of SERVER_READY and SERVER_STARTING.
*/
for loop if no pid? not much else matters */
if (status <= SERVER_READY &&
}
}
}
}
if (any_dead_threads
if (all_dead_threads) {
/* great! we prefer these, because the new process can
* start more threads sooner. So prioritize this slot
* by putting it ahead of any slots with active threads.
*
* first, make room by moving a slot that's potentially still
* in use to the end of the array
*/
free_slots[totally_free_length++] = i;
}
else {
/* slot is still in use - back of the bus
*/
free_slots[free_length] = i;
}
++free_length;
}
/* XXX if (!ps->quiescing) is probably more reliable GLA */
if (!any_dying_threads) {
last_non_dead = i;
}
}
if (sick_child_detected) {
if (active_thread_count > 0) {
/* some child processes appear to be working. don't kill the
* whole server.
*/
sick_child_detected = 0;
}
else {
/* looks like a basket case. give up.
*/
shutdown_pending = 1;
child_fatal = 1;
"No active workers found..."
" Apache is exiting!");
/* the child already logged the failure details */
return;
}
}
if (idle_thread_count > max_spare_threads) {
/* Kill off one child */
idle_spawn_rate = 1;
}
else if (idle_thread_count < min_spare_threads) {
/* terminate the free list */
if (free_length == 0) { /* scoreboard is full, can't fork */
static int reported = 0;
if (!reported) {
/* only report this condition once */
"server reached MaxClients setting, consider"
" raising the MaxClients setting");
reported = 1;
}
}
else {
"scoreboard is full, not at MaxClients");
}
idle_spawn_rate = 1;
}
else {
if (free_length > idle_spawn_rate) {
}
if (idle_spawn_rate >= 8) {
"server seems busy, (you may need "
"to increase StartServers, ThreadsPerChild "
"or Min/MaxSpareThreads), "
"spawning %d children, there are around %d idle "
"threads, and %d total children", free_length,
}
for (i = 0; i < free_length; ++i) {
}
/* the next time around we want to spawn twice as many if this
* wasn't good enough, but not if we've just done a graceful
*/
}
else if (idle_spawn_rate < MAX_SPAWN_RATE) {
idle_spawn_rate *= 2;
}
}
}
else {
idle_spawn_rate = 1;
}
}
static void server_main_loop(int remaining_children_to_start)
{
int child_slot;
int status, processed_status;
int i;
while (!restart_pending && !shutdown_pending) {
if (processed_status == APEXIT_CHILDFATAL) {
shutdown_pending = 1;
child_fatal = 1;
return;
}
else if (processed_status == APEXIT_CHILDSICK) {
/* tell perform_idle_server_maintenance to check into this
* on the next timer pop
*/
sick_child_detected = 1;
}
/* non-fatal death... note that it's gone in the scoreboard. */
if (child_slot >= 0) {
for (i = 0; i < ap_threads_per_child; i++)
(request_rec *) NULL);
if (processed_status == APEXIT_CHILDSICK) {
/* resource shortage, minimize the fork rate */
idle_spawn_rate = 1;
}
else if (remaining_children_to_start
&& child_slot < ap_daemons_limit) {
/* we're still doing a 1-for-1 replacement of dead
* children with new children
*/
}
}
status) == 0) {
/* handled */
#endif
}
else if (is_graceful) {
/* Great, we've probably just lost a slot in the
* scoreboard. Somehow we don't know about this child.
*/
"long lost child came home! (pid %ld)",
}
/* 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.
*/
/* 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;
}
}
}
{
if (!is_graceful) {
return 1;
}
/* fix the generation number in the global score; we just got a new,
* cleared scoreboard
*/
}
set_signals();
/* Don't thrash... */
/* 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.
*/
}
if (!is_graceful) {
}
else {
/* give the system some time to recover before kicking into
* exponential mode */
}
"%s configured -- resuming normal operations",
"Server built: %s", ap_get_server_built());
restart_pending = shutdown_pending = 0;
if (shutdown_pending && !is_graceful) {
/* Time to shut down:
* Kill child processes, tell them to call child_exit, etc...
*/
if (!child_fatal) {
/* cleanup pid file on normal shutdown */
"removed PID file %s (pid=%ld)",
ap_server_conf, "caught SIGTERM, shutting down");
}
return 1;
} else if (shutdown_pending) {
/* Time to gracefully shut down:
* Kill child processes, tell them to call child_exit, etc...
*/
int active_children;
int index;
apr_time_t cutoff = 0;
/* Close our listeners, and then ask our children to do same */
if (!child_fatal) {
/* cleanup pid file on normal shutdown */
"removed PID file %s (pid=%ld)",
"caught " AP_SIG_GRACEFUL_STOP_STRING
", shutting down gracefully");
}
if (ap_graceful_shutdown_timeout) {
cutoff = apr_time_now() +
}
/* Don't really exit until each child has finished */
shutdown_pending = 0;
do {
/* Pause for a second */
/* Relieve any children which have now exited */
active_children = 0;
if (MPM_CHILD_PID(index) != 0) {
active_children = 1;
/* Having just one child is enough to stay around */
break;
}
}
}
} while (!shutdown_pending && active_children &&
/* We might be here because we received SIGTERM, either
* way, try and make sure that all of our processes are
* really dead.
*/
return 1;
}
/* we've been told to restart */
if (one_process) {
/* not worth thinking about */
return 1;
}
/* advance to the next generation */
/* XXX: we really need to make sure this new generation number isn't in
* use by any of the children.
*/
if (is_graceful) {
" received. Doing graceful restart");
/* wake up the children...time to die. But we'll have more soon */
/* 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.
*/
"SIGHUP received. Attempting to restart");
}
return 0;
}
/* This really should be a post_config hook, but the error log is already
* redirected by that point, so we need to do this in the open_logs phase.
*/
{
static int restart_num = 0;
int startup = 0;
int level_flags = 0;
pconf = p;
ap_server_conf = s;
/* the reverse of pre_config, we want this only the first time around */
if (restart_num++ == 0) {
startup = 1;
}
"no listening sockets available, shutting down");
return DONE;
}
if (!one_process) {
"could not open pipe-of-death");
return DONE;
}
}
return OK;
}
apr_pool_t * ptemp)
{
static int restart_num = 0;
if (debug) {
no_detach = 0;
}
else {
}
/* sigh, want this only the second time around */
if (restart_num++ == 1) {
is_graceful = 0;
if (rv != APR_SUCCESS) {
"Couldn't create a Thread Safe Pollset. "
"Is it supported on your platform?");
return HTTP_INTERNAL_SERVER_ERROR;
}
if (!one_process && !foreground) {
if (rv != APR_SUCCESS) {
"apr_proc_detach failed");
return HTTP_INTERNAL_SERVER_ERROR;
}
}
}
ap_extended_status = 0;
#ifdef AP_MPM_WANT_SET_MAX_MEM_FREE
#endif
return OK;
}
{
static int restart_num = 0;
int startup = 0;
/* the reverse of pre_config, we want this only the first time around */
if (restart_num++ == 0) {
startup = 1;
}
if (server_limit > MAX_SERVER_LIMIT) {
if (startup) {
"WARNING: ServerLimit of %d exceeds compile-time "
"limit of", server_limit);
" %d servers, decreasing to %d.",
} else {
"ServerLimit of %d exceeds compile-time limit "
"of %d, decreasing to match",
}
}
else if (server_limit < 1) {
if (startup) {
"WARNING: ServerLimit of %d not allowed, "
"increasing to 1.", server_limit);
} else {
"ServerLimit of %d not allowed, increasing to 1",
}
server_limit = 1;
}
/* you cannot change ServerLimit across a restart; ignore
* any such attempts
*/
if (!first_server_limit) {
}
else if (server_limit != first_server_limit) {
/* don't need a startup console version here */
"changing ServerLimit to %d from original value of %d "
"not allowed during restart",
}
if (thread_limit > MAX_THREAD_LIMIT) {
if (startup) {
"WARNING: ThreadLimit of %d exceeds compile-time "
"limit of", thread_limit);
" %d threads, decreasing to %d.",
} else {
"ThreadLimit of %d exceeds compile-time limit "
"of %d, decreasing to match",
}
}
else if (thread_limit < 1) {
if (startup) {
"WARNING: ThreadLimit of %d not allowed, "
"increasing to 1.", thread_limit);
} else {
"ThreadLimit of %d not allowed, increasing to 1",
}
thread_limit = 1;
}
/* you cannot change ThreadLimit across a restart; ignore
* any such attempts
*/
if (!first_thread_limit) {
}
else if (thread_limit != first_thread_limit) {
/* don't need a startup console version here */
"changing ThreadLimit to %d from original value of %d "
"not allowed during restart",
}
if (ap_threads_per_child > thread_limit) {
if (startup) {
"WARNING: ThreadsPerChild of %d exceeds ThreadLimit "
"of", ap_threads_per_child);
" %d threads, decreasing to %d.",
" To increase, please see the ThreadLimit "
"directive.");
} else {
"ThreadsPerChild of %d exceeds ThreadLimit "
"of %d, decreasing to match",
}
}
else if (ap_threads_per_child < 1) {
if (startup) {
"WARNING: ThreadsPerChild of %d not allowed, "
"increasing to 1.", ap_threads_per_child);
} else {
"ThreadsPerChild of %d not allowed, increasing to 1",
}
ap_threads_per_child = 1;
}
if (max_clients < ap_threads_per_child) {
if (startup) {
"WARNING: MaxClients of %d is less than "
"ThreadsPerChild of", max_clients);
" %d, increasing to %d. MaxClients must be at "
"least as large",
" as the number of threads in a single server.");
} else {
"MaxClients of %d is less than ThreadsPerChild "
"of %d, increasing to match",
}
}
if (max_clients % ap_threads_per_child) {
if (startup) {
"WARNING: MaxClients of %d is not an integer "
"multiple of", max_clients);
" ThreadsPerChild of %d, decreasing to nearest "
"multiple %d,", ap_threads_per_child,
" for a maximum of %d servers.",
} else {
"MaxClients of %d is not an integer multiple of "
"ThreadsPerChild of %d, decreasing to nearest "
}
}
if (ap_daemons_limit > server_limit) {
if (startup) {
"WARNING: MaxClients of %d would require %d "
" would exceed ServerLimit of %d, decreasing to %d.",
" To increase, please see the ServerLimit "
"directive.");
} else {
"MaxClients of %d would require %d servers and "
"exceed ServerLimit of %d, decreasing to %d",
}
}
/* ap_daemons_to_start > ap_daemons_limit checked in ap_mpm_run() */
if (ap_daemons_to_start < 0) {
if (startup) {
"WARNING: StartServers of %d not allowed, "
"increasing to 1.", ap_daemons_to_start);
} else {
"StartServers of %d not allowed, increasing to 1",
}
ap_daemons_to_start = 1;
}
if (min_spare_threads < 1) {
if (startup) {
"WARNING: MinSpareThreads of %d not allowed, "
"increasing to 1", min_spare_threads);
" to avoid almost certain server failure.");
" Please read the documentation.");
} else {
"MinSpareThreads of %d not allowed, increasing to 1",
}
min_spare_threads = 1;
}
/* max_spare_threads < min_spare_threads + ap_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.
*/
one_process = 0;
/* we need to set the MPM state before other pre-config hooks use MPM query
* to retrieve it, so register as REALLY_FIRST
*/
}
const char *arg)
{
return err;
}
return NULL;
}
const char *arg)
{
return err;
}
return NULL;
}
const char *arg)
{
return err;
}
return NULL;
}
const char *arg)
{
return err;
}
return NULL;
}
const char *arg)
{
return err;
}
return NULL;
}
{
return err;
}
return NULL;
}
const char *arg)
{
return err;
}
return NULL;
}
static const command_rec event_cmds[] = {
"Number of child processes launched at server startup"),
"Maximum number of child processes for this run of Apache"),
"Minimum number of idle threads, to handle request spikes"),
"Maximum number of idle threads"),
"Maximum number of threads alive at the same time"),
"Number of threads each child creates"),
"Maximum number of worker threads per child process for this "
"run of Apache - Upper limit for ThreadsPerChild"),
{NULL}
};
ap_mpm_rewrite_args, /* hook to run before apache parses args */
NULL, /* create per-directory config structure */
NULL, /* merge per-directory config structures */
NULL, /* create per-server config structure */
NULL, /* merge per-server config structures */
event_cmds, /* command apr_table_t */
event_hooks /* register_hooks */
};