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cve-2024-38477/httpd-2.4.59/server/mpm/worker/worker.c
gbucchino 86ef235216 First commit
2025-06-05 15:09:30 +02:00

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/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* The purpose of this MPM is to fix the design flaws in the threaded
* model. Because of the way that pthreads and mutex locks interact,
* it is basically impossible to cleanly gracefully shutdown a child
* process if multiple threads are all blocked in accept. This model
* fixes those problems.
*/
#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 <stdlib.h>
#define APR_WANT_STRFUNC
#include "apr_want.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 Worker 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 "ap_mpm.h"
#include "mpm_common.h"
#include "ap_listen.h"
#include "scoreboard.h"
#include "mpm_fdqueue.h"
#include "mpm_default.h"
#include "util_mutex.h"
#include "unixd.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 * server_limit 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 20000
#endif
/*
* Actual definitions of config globals
*/
static int 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_workers = 0;
static int server_limit = 0;
static int thread_limit = 0;
static int had_healthy_child = 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 apr_pollset_t *worker_pollset;
/* data retained by worker across load/unload of the module
* allocated on first call to pre-config hook; located on
* subsequent calls to pre-config hook
*/
typedef struct worker_retained_data {
ap_unixd_mpm_retained_data *mpm;
int first_server_limit;
int first_thread_limit;
int sick_child_detected;
int maxclients_reported;
int near_maxclients_reported;
/*
* The max child slot ever assigned, preserved across restarts. Necessary
* to deal with MaxRequestWorkers changes across AP_SIG_GRACEFUL restarts.
* We use this value to optimize routines that have to scan the entire
* scoreboard.
*/
int max_daemons_limit;
/*
* 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;
} worker_retained_data;
static worker_retained_data *retained;
typedef struct worker_child_bucket {
ap_pod_t *pod;
ap_listen_rec *listeners;
apr_proc_mutex_t *mutex;
} worker_child_bucket;
static worker_child_bucket *all_buckets, /* All listeners buckets */
*my_bucket; /* Current child bucket */
#define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid)
/* 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 {
apr_thread_t **threads;
apr_thread_t *listener;
int child_num_arg;
apr_threadattr_t *threadattr;
} thread_starter;
#define ID_FROM_CHILD_THREAD(c, t) ((c * thread_limit) + t)
/* 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
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;
#ifdef SINGLE_LISTEN_UNSERIALIZED_ACCEPT
#define SAFE_ACCEPT(stmt) (ap_listeners->next ? (stmt) : APR_SUCCESS)
#else
#define SAFE_ACCEPT(stmt) (stmt)
#endif
/* 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
/* The WORKER_SIGNAL signal will be sent from the main thread to the
* worker threads during an ungraceful restart or shutdown.
* This ensures that on systems (i.e., Linux) where closing the worker
* socket doesn't awake the worker thread when it is polling on the socket
* (especially in apr_wait_for_io_or_timeout() when handling
* Keep-Alive connections), close_worker_sockets() and join_workers()
* still function in timely manner and allow ungraceful shutdowns to
* proceed to completion. Otherwise join_workers() doesn't return
* before the main process decides the child process is non-responsive
* and sends a SIGKILL.
*/
#define WORKER_SIGNAL AP_SIG_GRACEFUL
/* 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 < threads_per_child; i++) {
if (worker_sockets[i]) {
apr_socket_close(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;
}
/* unblock the listener if it's waiting for a worker */
ap_queue_info_term(worker_queue_info);
/*
* 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 worker_query(int query_code, int *result, apr_status_t *rv)
{
*rv = APR_SUCCESS;
switch (query_code) {
case AP_MPMQ_MAX_DAEMON_USED:
*result = retained->max_daemons_limit;
break;
case AP_MPMQ_IS_THREADED:
*result = AP_MPMQ_STATIC;
break;
case AP_MPMQ_IS_FORKED:
*result = AP_MPMQ_DYNAMIC;
break;
case AP_MPMQ_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 = ap_daemons_limit;
break;
case AP_MPMQ_MPM_STATE:
*result = retained->mpm->mpm_state;
break;
case AP_MPMQ_GENERATION:
*result = retained->mpm->my_generation;
break;
default:
*rv = APR_ENOTIMPL;
break;
}
return OK;
}
static void worker_note_child_killed(int childnum, pid_t pid, ap_generation_t gen)
{
if (childnum != -1) { /* child had a scoreboard slot? */
ap_run_child_status(ap_server_conf,
ap_scoreboard_image->parent[childnum].pid,
ap_scoreboard_image->parent[childnum].generation,
childnum, MPM_CHILD_EXITED);
ap_scoreboard_image->parent[childnum].pid = 0;
}
else {
ap_run_child_status(ap_server_conf, pid, gen, -1, MPM_CHILD_EXITED);
}
}
static void worker_note_child_started(int slot, pid_t pid)
{
ap_generation_t gen = retained->mpm->my_generation;
ap_scoreboard_image->parent[slot].pid = pid;
ap_scoreboard_image->parent[slot].generation = gen;
ap_run_child_status(ap_server_conf, pid, gen, slot, MPM_CHILD_STARTED);
}
static void worker_note_child_lost_slot(int slot, pid_t newpid)
{
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00263)
"pid %" APR_PID_T_FMT " taking over scoreboard slot from "
"%" APR_PID_T_FMT "%s",
newpid,
ap_scoreboard_image->parent[slot].pid,
ap_scoreboard_image->parent[slot].quiescing ?
" (quiescing)" : "");
ap_run_child_status(ap_server_conf,
ap_scoreboard_image->parent[slot].pid,
ap_scoreboard_image->parent[slot].generation,
slot, MPM_CHILD_LOST_SLOT);
/* Don't forget about this exiting child process, or we
* won't be able to kill it if it doesn't exit by the
* time the server is shut down.
*/
ap_register_extra_mpm_process(ap_scoreboard_image->parent[slot].pid,
ap_scoreboard_image->parent[slot].generation);
}
static const char *worker_get_name(void)
{
return "worker";
}
/* 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) {
worker_note_child_killed(/* slot */ 0, 0, 0);
}
exit(code);
}
static void just_die(int sig)
{
clean_child_exit(0);
}
/*****************************************************************
* Connection structures and accounting...
*/
static int child_fatal;
/*****************************************************************
* Here follows a long bunch of generic server bookkeeping stuff...
*/
/*****************************************************************
* Child process main loop.
*/
static void process_socket(apr_thread_t *thd, apr_pool_t *p, apr_socket_t *sock,
int my_child_num,
int my_thread_num, apr_bucket_alloc_t *bucket_alloc)
{
conn_rec *current_conn;
long conn_id = ID_FROM_CHILD_THREAD(my_child_num, my_thread_num);
ap_sb_handle_t *sbh;
ap_create_sb_handle(&sbh, p, my_child_num, my_thread_num);
current_conn = ap_run_create_connection(p, ap_server_conf, sock,
conn_id, sbh, bucket_alloc);
if (current_conn) {
current_conn->current_thread = thd;
ap_process_connection(current_conn, sock);
ap_lingering_close(current_conn);
}
}
/* requests_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) {
signal_threads(ST_GRACEFUL);
}
else {
requests_this_child = INT_MAX; /* keep going */
}
}
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 void accept_mutex_error(const char *func, apr_status_t rv, int process_slot)
{
int level = APLOG_EMERG;
if (ap_scoreboard_image->parent[process_slot].generation !=
ap_scoreboard_image->global->running_generation) {
level = APLOG_DEBUG; /* common to get these at restart time */
}
else if (requests_this_child == INT_MAX
|| ((requests_this_child == ap_max_requests_per_child)
&& ap_max_requests_per_child)) {
ap_log_error(APLOG_MARK, level, rv, ap_server_conf, APLOGNO(00272)
"apr_proc_mutex_%s failed "
"before this child process served any requests.",
func);
clean_child_exit(APEXIT_CHILDSICK);
}
ap_log_error(APLOG_MARK, level, rv, ap_server_conf, APLOGNO(00273)
"apr_proc_mutex_%s failed. Attempting to "
"shutdown process gracefully.", func);
signal_threads(ST_GRACEFUL);
}
static void * APR_THREAD_FUNC listener_thread(apr_thread_t *thd, void * dummy)
{
proc_info * ti = dummy;
int process_slot = ti->pid;
void *csd = NULL;
apr_pool_t *ptrans = NULL; /* Pool for per-transaction stuff */
apr_status_t rv;
ap_listen_rec *lr = NULL;
int have_idle_worker = 0;
int last_poll_idx = 0;
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);
/* TODO: Switch to a system where threads reuse the results from earlier
poll calls - manoj */
while (1) {
/* TODO: requests_this_child should be synchronized - aaron */
if (requests_this_child <= 0) {
check_infinite_requests();
}
if (listener_may_exit) break;
if (!have_idle_worker) {
rv = ap_queue_info_wait_for_idler(worker_queue_info, NULL);
if (APR_STATUS_IS_EOF(rv)) {
break; /* we've been signaled to die now */
}
else if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
"apr_queue_info_wait failed. Attempting to "
" shutdown process gracefully.");
signal_threads(ST_GRACEFUL);
break;
}
have_idle_worker = 1;
}
/* We've already decremented the idle worker count inside
* ap_queue_info_wait_for_idler. */
if ((rv = SAFE_ACCEPT(apr_proc_mutex_lock(my_bucket->mutex)))
!= APR_SUCCESS) {
if (!listener_may_exit) {
accept_mutex_error("lock", rv, process_slot);
}
break; /* skip the lock release */
}
if (!my_bucket->listeners->next) {
/* Only one listener, so skip the poll */
lr = my_bucket->listeners;
}
else {
while (!listener_may_exit) {
apr_int32_t numdesc;
const apr_pollfd_t *pdesc;
rv = apr_pollset_poll(worker_pollset, -1, &numdesc, &pdesc);
if (rv != APR_SUCCESS) {
if (APR_STATUS_IS_EINTR(rv)) {
continue;
}
/* apr_pollset_poll() will only return errors in catastrophic
* circumstances. Let's try exiting gracefully, for now. */
ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03137)
"apr_pollset_poll: (listen)");
signal_threads(ST_GRACEFUL);
}
if (listener_may_exit) break;
/* We can always use pdesc[0], but sockets at position N
* could end up completely starved of attention in a very
* busy server. Therefore, we round-robin across the
* returned set of descriptors. While it is possible that
* the returned set of descriptors might flip around and
* continue to starve some sockets, we happen to know the
* internal pollset implementation retains ordering
* stability of the sockets. Thus, the round-robin should
* ensure that a socket will eventually be serviced.
*/
if (last_poll_idx >= numdesc)
last_poll_idx = 0;
/* Grab a listener record from the client_data of the poll
* descriptor, and advance our saved index to round-robin
* the next fetch.
*
* ### hmm... this descriptor might have POLLERR rather
* ### than POLLIN
*/
lr = pdesc[last_poll_idx++].client_data;
break;
} /* while */
} /* if/else */
if (!listener_may_exit) {
/* the following pops a recycled ptrans pool off a stack */
ap_queue_info_pop_pool(worker_queue_info, &ptrans);
if (ptrans == NULL) {
/* we can't use a recycled transaction pool this time.
* create a new transaction pool */
apr_allocator_t *allocator;
apr_allocator_create(&allocator);
apr_allocator_max_free_set(allocator, ap_max_mem_free);
apr_pool_create_ex(&ptrans, pconf, NULL, allocator);
apr_allocator_owner_set(allocator, ptrans);
apr_pool_tag(ptrans, "transaction");
}
rv = lr->accept_func(&csd, lr, ptrans);
/* later we trash rv and rely on csd to indicate success/failure */
AP_DEBUG_ASSERT(rv == APR_SUCCESS || !csd);
if (rv == APR_EGENERAL) {
/* E[NM]FILE, ENOMEM, etc */
resource_shortage = 1;
signal_threads(ST_GRACEFUL);
}
if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(my_bucket->mutex)))
!= APR_SUCCESS) {
if (listener_may_exit) {
break;
}
accept_mutex_error("unlock", rv, process_slot);
}
if (csd != NULL) {
rv = ap_queue_push_socket(worker_queue, csd, NULL, ptrans);
if (rv) {
/* trash the connection; we couldn't queue the connected
* socket to a worker
*/
apr_socket_close(csd);
ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(03138)
"ap_queue_push_socket failed");
}
else {
have_idle_worker = 0;
}
}
}
else {
if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(my_bucket->mutex)))
!= APR_SUCCESS) {
int level = APLOG_EMERG;
if (ap_scoreboard_image->parent[process_slot].generation !=
ap_scoreboard_image->global->running_generation) {
level = APLOG_DEBUG; /* common to get these at restart time */
}
ap_log_error(APLOG_MARK, level, rv, ap_server_conf, APLOGNO(00274)
"apr_proc_mutex_unlock failed. Attempting to "
"shutdown process gracefully.");
signal_threads(ST_GRACEFUL);
}
break;
}
}
ap_close_listeners_ex(my_bucket->listeners);
ap_queue_info_free_idle_pools(worker_queue_info);
ap_queue_term(worker_queue);
dying = 1;
ap_scoreboard_image->parent[process_slot].quiescing = 1;
/* wake up the main thread */
kill(ap_my_pid, SIGTERM);
apr_thread_exit(thd, APR_SUCCESS);
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.
*/
static void * APR_THREAD_FUNC worker_thread(apr_thread_t *thd, void * dummy)
{
proc_info * ti = dummy;
int process_slot = ti->pid;
int thread_slot = ti->tid;
apr_socket_t *csd = NULL;
apr_bucket_alloc_t *bucket_alloc;
apr_pool_t *last_ptrans = NULL;
apr_pool_t *ptrans; /* Pool for per-transaction stuff */
apr_status_t rv;
int is_idle = 0;
free(ti);
ap_scoreboard_image->servers[process_slot][thread_slot].pid = ap_my_pid;
ap_scoreboard_image->servers[process_slot][thread_slot].tid = apr_os_thread_current();
ap_scoreboard_image->servers[process_slot][thread_slot].generation = retained->mpm->my_generation;
ap_update_child_status_from_indexes(process_slot, thread_slot,
SERVER_STARTING, NULL);
#ifdef HAVE_PTHREAD_KILL
apr_signal(WORKER_SIGNAL, dummy_signal_handler);
unblock_signal(WORKER_SIGNAL);
#endif
while (!workers_may_exit) {
if (!is_idle) {
rv = ap_queue_info_set_idle(worker_queue_info, last_ptrans);
last_ptrans = NULL;
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
"ap_queue_info_set_idle failed. Attempting to "
"shutdown process gracefully.");
signal_threads(ST_GRACEFUL);
break;
}
is_idle = 1;
}
ap_update_child_status_from_indexes(process_slot, thread_slot,
SERVER_READY, NULL);
worker_pop:
if (workers_may_exit) {
break;
}
rv = ap_queue_pop_socket(worker_queue, &csd, &ptrans);
if (rv != APR_SUCCESS) {
/* We get APR_EOF during a graceful shutdown once all the connections
* accepted by this server process have been handled.
*/
if (APR_STATUS_IS_EOF(rv)) {
break;
}
/* We get APR_EINTR whenever ap_queue_pop_*() has been interrupted
* from an explicit call to ap_queue_interrupt_all(). This allows
* us to unblock threads stuck in ap_queue_pop_*() when a shutdown
* is pending.
*
* If workers_may_exit is set and this is ungraceful termination/
* restart, we are bound to get an error on some systems (e.g.,
* AIX, which sanity-checks mutex operations) since the queue
* may have already been cleaned up. Don't log the "error" if
* workers_may_exit is set.
*/
else if (APR_STATUS_IS_EINTR(rv)) {
goto worker_pop;
}
/* We got some other error. */
else if (!workers_may_exit) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(03139)
"ap_queue_pop_socket failed");
}
continue;
}
is_idle = 0;
worker_sockets[thread_slot] = csd;
bucket_alloc = apr_bucket_alloc_create(ptrans);
process_socket(thd, ptrans, csd, process_slot, thread_slot, bucket_alloc);
worker_sockets[thread_slot] = NULL;
requests_this_child--;
apr_pool_clear(ptrans);
last_ptrans = ptrans;
}
ap_update_child_status_from_indexes(process_slot, thread_slot,
dying ? SERVER_DEAD
: SERVER_GRACEFUL, NULL);
apr_thread_exit(thd, APR_SUCCESS);
return NULL;
}
static int check_signal(int signum)
{
switch (signum) {
case SIGTERM:
case SIGINT:
return 1;
}
return 0;
}
static void create_listener_thread(thread_starter *ts)
{
int my_child_num = ts->child_num_arg;
apr_threadattr_t *thread_attr = ts->threadattr;
proc_info *my_info;
apr_status_t rv;
my_info = (proc_info *)ap_malloc(sizeof(proc_info));
my_info->pid = my_child_num;
my_info->tid = -1; /* listener thread doesn't have a thread slot */
my_info->sd = 0;
rv = ap_thread_create(&ts->listener, thread_attr, listener_thread,
my_info, pruntime);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(00275)
"ap_thread_create: unable to create listener thread");
/* let the parent decide how bad this really is */
clean_child_exit(APEXIT_CHILDSICK);
}
apr_os_thread_get(&listener_os_thread, ts->listener);
}
static void setup_threads_runtime(void)
{
ap_listen_rec *lr;
apr_status_t rv;
/* All threads (listener, workers) and synchronization objects (queues,
* pollset, mutexes...) created here should have at least the lifetime of
* the connections they handle (i.e. ptrans). We can't use this thread's
* self pool because all these objects survive it, nor use pchild or pconf
* directly because this starter thread races with other modules' runtime,
* nor finally pchild (or subpool thereof) because it is killed explicitly
* before pconf (thus connections/ptrans can live longer, which matters in
* ONE_PROCESS mode). So this leaves us with a subpool of pconf, created
* before any ptrans hence destroyed after.
*/
apr_pool_create(&pruntime, pconf);
apr_pool_tag(pruntime, "mpm_runtime");
/* We must create the fd queues before we start up the listener
* and worker threads. */
rv = ap_queue_create(&worker_queue, threads_per_child, pruntime);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03140)
"ap_queue_create() failed");
clean_child_exit(APEXIT_CHILDFATAL);
}
rv = ap_queue_info_create(&worker_queue_info, pruntime,
threads_per_child, -1);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03141)
"ap_queue_info_create() failed");
clean_child_exit(APEXIT_CHILDFATAL);
}
/* Create the main pollset */
rv = apr_pollset_create(&worker_pollset, num_listensocks, pruntime,
APR_POLLSET_NOCOPY);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(03285)
"Couldn't create pollset in thread;"
" check system or user limits");
/* let the parent decide how bad this really is */
clean_child_exit(APEXIT_CHILDSICK);
}
for (lr = my_bucket->listeners; lr != NULL; lr = lr->next) {
apr_pollfd_t *pfd = apr_pcalloc(pruntime, sizeof *pfd);
pfd->desc_type = APR_POLL_SOCKET;
pfd->desc.s = lr->sd;
pfd->reqevents = APR_POLLIN;
pfd->client_data = lr;
rv = apr_pollset_add(worker_pollset, pfd);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(03286)
"Couldn't create add listener to pollset;"
" check system or user limits");
/* let the parent decide how bad this really is */
clean_child_exit(APEXIT_CHILDSICK);
}
lr->accept_func = ap_unixd_accept;
}
worker_sockets = apr_pcalloc(pruntime, threads_per_child *
sizeof(apr_socket_t *));
}
/* XXX under some circumstances not understood, children can get stuck
* in start_threads forever trying to take over slots which will
* never be cleaned up; for now there is an APLOG_DEBUG message issued
* every so often when this condition occurs
*/
static void * APR_THREAD_FUNC start_threads(apr_thread_t *thd, void *dummy)
{
thread_starter *ts = dummy;
apr_thread_t **threads = ts->threads;
apr_threadattr_t *thread_attr = ts->threadattr;
int my_child_num = ts->child_num_arg;
proc_info *my_info;
apr_status_t rv;
int threads_created = 0;
int listener_started = 0;
int prev_threads_created;
int loops, i;
loops = prev_threads_created = 0;
while (1) {
/* threads_per_child does not include the listener thread */
for (i = 0; i < threads_per_child; i++) {
int status = ap_scoreboard_image->servers[my_child_num][i].status;
if (status != SERVER_GRACEFUL && status != SERVER_DEAD) {
continue;
}
my_info = (proc_info *)ap_malloc(sizeof(proc_info));
my_info->pid = my_child_num;
my_info->tid = i;
my_info->sd = 0;
/* We are creating threads right now */
ap_update_child_status_from_indexes(my_child_num, i,
SERVER_STARTING, NULL);
/* We let each thread update its own scoreboard entry. This is
* done because it lets us deal with tid better.
*/
rv = ap_thread_create(&threads[i], thread_attr,
worker_thread, my_info, pruntime);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03142)
"ap_thread_create: unable to create worker thread");
/* let the parent decide how bad this really is */
clean_child_exit(APEXIT_CHILDSICK);
}
threads_created++;
}
/* Start the listener only when there are workers available */
if (!listener_started && threads_created) {
create_listener_thread(ts);
listener_started = 1;
}
if (start_thread_may_exit || threads_created == threads_per_child) {
break;
}
/* wait for previous generation to clean up an entry */
apr_sleep(apr_time_from_sec(1));
++loops;
if (loops % 120 == 0) { /* every couple of minutes */
if (prev_threads_created == threads_created) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
"child %" APR_PID_T_FMT " isn't taking over "
"slots very quickly (%d of %d)",
ap_my_pid, threads_created, threads_per_child);
}
prev_threads_created = threads_created;
}
}
/* What state should this child_main process be listed as in the
* scoreboard...?
* ap_update_child_status_from_indexes(my_child_num, i, SERVER_STARTING,
* (request_rec *) NULL);
*
* This state should be listed separately in the scoreboard, in some kind
* of process_status, not mixed in with the worker threads' status.
* "life_status" is almost right, but it's in the worker's structure, and
* the name could be clearer. gla
*/
apr_thread_exit(thd, APR_SUCCESS);
return NULL;
}
static void join_workers(apr_thread_t *listener, apr_thread_t **threads,
int mode)
{
int i;
apr_status_t rv, thread_rv;
if (listener) {
int iter;
/* deal with a rare timing window which affects waking up the
* listener thread... if the signal sent to the listener thread
* is delivered between the time it verifies that the
* listener_may_exit flag is clear and the time it enters a
* blocking syscall, the signal didn't do any good... work around
* that by sleeping briefly and sending it again
*/
iter = 0;
while (iter < 10 &&
#ifdef HAVE_PTHREAD_KILL
pthread_kill(*listener_os_thread, 0)
#else
kill(ap_my_pid, 0)
#endif
== 0) {
/* listener not dead yet */
apr_sleep(apr_time_make(0, 500000));
wakeup_listener();
++iter;
}
if (iter >= 10) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00276)
"the listener thread didn't exit");
}
else {
rv = apr_thread_join(&thread_rv, listener);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(00277)
"apr_thread_join: unable to join listener thread");
}
}
}
for (i = 0; i < threads_per_child; i++) {
if (threads[i]) { /* if we ever created this thread */
if (mode != ST_GRACEFUL) {
#ifdef HAVE_PTHREAD_KILL
apr_os_thread_t *worker_os_thread;
apr_os_thread_get(&worker_os_thread, threads[i]);
pthread_kill(*worker_os_thread, WORKER_SIGNAL);
#endif
}
rv = apr_thread_join(&thread_rv, threads[i]);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(00278)
"apr_thread_join: unable to join worker "
"thread %d",
i);
}
}
}
}
static void join_start_thread(apr_thread_t *start_thread_id)
{
apr_status_t rv, thread_rv;
start_thread_may_exit = 1; /* tell it to give up in case it is still
* trying to take over slots from a
* previous generation
*/
rv = apr_thread_join(&thread_rv, start_thread_id);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(00279)
"apr_thread_join: unable to join the start "
"thread");
}
}
static void child_main(int child_num_arg, int child_bucket)
{
apr_thread_t **threads;
apr_status_t rv;
thread_starter *ts;
apr_threadattr_t *thread_attr;
apr_thread_t *start_thread_id;
int i;
/* for benefit of any hooks that run as this child initializes */
retained->mpm->mpm_state = AP_MPMQ_STARTING;
ap_my_pid = getpid();
ap_fatal_signal_child_setup(ap_server_conf);
/* Get a sub context for global allocations in this child, so that
* we can have cleanups occur when the child exits.
*/
apr_pool_create(&pchild, pconf);
apr_pool_tag(pchild, "pchild");
#if AP_HAS_THREAD_LOCAL
if (!one_process) {
apr_thread_t *thd = NULL;
if ((rv = ap_thread_main_create(&thd, pchild))) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(10375)
"Couldn't initialize child main thread");
clean_child_exit(APEXIT_CHILDFATAL);
}
}
#endif
/* close unused listeners and pods */
for (i = 0; i < retained->mpm->num_buckets; i++) {
if (i != child_bucket) {
ap_close_listeners_ex(all_buckets[i].listeners);
ap_mpm_podx_close(all_buckets[i].pod);
}
}
/*stuff to do before we switch id's, so we have permissions.*/
ap_reopen_scoreboard(pchild, NULL, 0);
rv = SAFE_ACCEPT(apr_proc_mutex_child_init(&my_bucket->mutex,
apr_proc_mutex_lockfile(my_bucket->mutex),
pchild));
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(00280)
"Couldn't initialize cross-process lock in child");
clean_child_exit(APEXIT_CHILDFATAL);
}
/* done with init critical section */
if (ap_run_drop_privileges(pchild, ap_server_conf)) {
clean_child_exit(APEXIT_CHILDFATAL);
}
/* Just use the standard apr_setup_signal_thread to block all signals
* from being received. The child processes no longer use signals for
* any communication with the parent process. Let's also do this before
* child_init() hooks are called and possibly create threads that
* otherwise could "steal" (implicitly) MPM's signals.
*/
rv = apr_setup_signal_thread();
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(00281)
"Couldn't initialize signal thread");
clean_child_exit(APEXIT_CHILDFATAL);
}
ap_run_child_init(pchild, ap_server_conf);
if (ap_max_requests_per_child) {
requests_this_child = ap_max_requests_per_child;
}
else {
/* coding a value of zero means infinity */
requests_this_child = INT_MAX;
}
/* Setup threads */
/* Globals used by signal_threads() so to be initialized before */
setup_threads_runtime();
/* clear the storage; we may not create all our threads immediately,
* and we want a 0 entry to indicate a thread which was not created
*/
threads = (apr_thread_t **)ap_calloc(1,
sizeof(apr_thread_t *) * threads_per_child);
ts = (thread_starter *)apr_palloc(pchild, sizeof(*ts));
apr_threadattr_create(&thread_attr, pchild);
/* 0 means PTHREAD_CREATE_JOINABLE */
apr_threadattr_detach_set(thread_attr, 0);
if (ap_thread_stacksize != 0) {
rv = apr_threadattr_stacksize_set(thread_attr, ap_thread_stacksize);
if (rv != APR_SUCCESS && rv != APR_ENOTIMPL) {
ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf, APLOGNO(02435)
"WARNING: ThreadStackSize of %" APR_SIZE_T_FMT " is "
"inappropriate, using default",
ap_thread_stacksize);
}
}
ts->threads = threads;
ts->listener = NULL;
ts->child_num_arg = child_num_arg;
ts->threadattr = thread_attr;
rv = ap_thread_create(&start_thread_id, thread_attr, start_threads,
ts, pchild);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(00282)
"ap_thread_create: unable to create worker thread");
/* let the parent decide how bad this really is */
clean_child_exit(APEXIT_CHILDSICK);
}
retained->mpm->mpm_state = AP_MPMQ_RUNNING;
/* If we are only running in one_process mode, we will want to
* still handle signals. */
if (one_process) {
/* Block until we get a terminating signal. */
apr_signal_thread(check_signal);
/* make sure the start thread has finished; signal_threads()
* and join_workers() depend on that
*/
/* XXX join_start_thread() won't be awakened if one of our
* threads encounters a critical error and attempts to
* shutdown this child
*/
join_start_thread(start_thread_id);
signal_threads(ST_UNGRACEFUL); /* 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).
*/
join_workers(ts->listener, threads, ST_UNGRACEFUL);
}
else { /* !one_process */
/* remove SIGTERM from the set of blocked signals... if one of
* the other threads in the process needs to take us down
* (e.g., for MaxConnectionsPerChild) it will send us SIGTERM
*/
apr_signal(SIGTERM, dummy_signal_handler);
unblock_signal(SIGTERM);
/* Watch for any messages from the parent over the POD */
while (1) {
rv = ap_mpm_podx_check(my_bucket->pod);
if (rv == AP_MPM_PODX_NORESTART) {
/* see if termination was triggered while we slept */
switch(terminate_mode) {
case ST_GRACEFUL:
rv = AP_MPM_PODX_GRACEFUL;
break;
case ST_UNGRACEFUL:
rv = AP_MPM_PODX_RESTART;
break;
}
}
if (rv == AP_MPM_PODX_GRACEFUL || rv == AP_MPM_PODX_RESTART) {
/* make sure the start thread has finished;
* signal_threads() and join_workers depend on that
*/
join_start_thread(start_thread_id);
signal_threads(rv == AP_MPM_PODX_GRACEFUL ? ST_GRACEFUL : ST_UNGRACEFUL);
break;
}
}
/* A terminating signal was received. Now join each of the
* workers to clean them up.
* If the worker already exited, then the join frees
* their resources and returns.
* If the worker hasn't exited, then this blocks until
* they have (then cleans up).
*/
join_workers(ts->listener, threads,
rv == AP_MPM_PODX_GRACEFUL ? ST_GRACEFUL : ST_UNGRACEFUL);
}
free(threads);
clean_child_exit(resource_shortage ? APEXIT_CHILDSICK : 0);
}
static int make_child(server_rec *s, int slot, int bucket)
{
int pid;
if (slot + 1 > retained->max_daemons_limit) {
retained->max_daemons_limit = slot + 1;
}
if (one_process) {
my_bucket = &all_buckets[0];
worker_note_child_started(slot, getpid());
child_main(slot, 0);
/* NOTREACHED */
ap_assert(0);
return -1;
}
if ((pid = fork()) == -1) {
ap_log_error(APLOG_MARK, APLOG_ERR, errno, s, APLOGNO(00283)
"fork: Unable to fork new process");
/* fork didn't succeed. There's no need to touch the scoreboard;
* if we were trying to replace a failed child process, then
* server_main_loop() marked its workers SERVER_DEAD, and if
* we were trying to replace a child process that exited normally,
* its worker_thread()s left SERVER_DEAD or SERVER_GRACEFUL behind.
*/
/* In case system resources are maxxed out, we don't want
Apache running away with the CPU trying to fork over and
over and over again. */
apr_sleep(apr_time_from_sec(10));
return -1;
}
if (!pid) {
#if AP_HAS_THREAD_LOCAL
ap_thread_current_after_fork();
#endif
my_bucket = &all_buckets[bucket];
#ifdef HAVE_BINDPROCESSOR
/* By default, AIX binds to a single processor. This bit unbinds
* children which will then bind to another CPU.
*/
int status = bindprocessor(BINDPROCESS, (int)getpid(),
PROCESSOR_CLASS_ANY);
if (status != OK)
ap_log_error(APLOG_MARK, APLOG_DEBUG, errno,
ap_server_conf, APLOGNO(00284)
"processor unbind failed");
#endif
RAISE_SIGSTOP(MAKE_CHILD);
apr_signal(SIGTERM, just_die);
child_main(slot, bucket);
/* NOTREACHED */
ap_assert(0);
return -1;
}
if (ap_scoreboard_image->parent[slot].pid != 0) {
/* This new child process is squatting on the scoreboard
* entry owned by an exiting child process, which cannot
* exit until all active requests complete.
*/
worker_note_child_lost_slot(slot, pid);
}
ap_scoreboard_image->parent[slot].quiescing = 0;
worker_note_child_started(slot, pid);
return 0;
}
/* start up a bunch of children */
static void startup_children(int number_to_start)
{
int i;
for (i = 0; number_to_start && i < ap_daemons_limit; ++i) {
if (ap_scoreboard_image->parent[i].pid != 0) {
continue;
}
if (make_child(ap_server_conf, i, i % retained->mpm->num_buckets) < 0) {
break;
}
--number_to_start;
}
}
static void perform_idle_server_maintenance(int child_bucket)
{
int num_buckets = retained->mpm->num_buckets;
int idle_thread_count;
process_score *ps;
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;
int i, j;
/* 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 threads_per_child is always > 0 */
int any_dying_threads = 0;
int any_dead_threads = 0;
int all_dead_threads = 1;
int child_threads_active = 0;
if (num_buckets > 1 && (i % num_buckets) != child_bucket) {
/* We only care about child_bucket in this call */
continue;
}
if (i >= retained->max_daemons_limit &&
totally_free_length == retained->idle_spawn_rate[child_bucket]) {
/* short cut if all active processes have been examined and
* enough empty scoreboard slots have been found
*/
break;
}
ps = &ap_scoreboard_image->parent[i];
for (j = 0; j < threads_per_child; j++) {
int status = ap_scoreboard_image->servers[i][j].status;
/* XXX any_dying_threads is probably no longer needed GLA */
any_dying_threads = any_dying_threads ||
(status == SERVER_GRACEFUL);
any_dead_threads = any_dead_threads || (status == SERVER_DEAD);
all_dead_threads = all_dead_threads &&
(status == SERVER_DEAD ||
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.
*/
if (ps->pid != 0) { /* XXX just set all_dead_threads in outer for
loop if no pid? not much else matters */
if (status <= SERVER_READY &&
!ps->quiescing &&
ps->generation == retained->mpm->my_generation) {
++idle_thread_count;
}
if (status >= SERVER_READY && status < SERVER_GRACEFUL) {
++child_threads_active;
}
}
}
active_thread_count += child_threads_active;
if (any_dead_threads
&& totally_free_length < retained->idle_spawn_rate[child_bucket]
&& free_length < MAX_SPAWN_RATE / num_buckets
&& (!ps->pid /* no process in the slot */
|| ps->quiescing)) { /* or at least one is going away */
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[free_length] = free_slots[totally_free_length];
free_slots[totally_free_length++] = i;
}
else {
/* slot is still in use - back of the bus
*/
free_slots[free_length] = i;
}
++free_length;
}
else if (child_threads_active == threads_per_child) {
had_healthy_child = 1;
}
/* XXX if (!ps->quiescing) is probably more reliable GLA */
if (!any_dying_threads) {
++total_non_dead;
}
if (ps->pid != 0) {
last_non_dead = i;
}
}
retained->max_daemons_limit = last_non_dead + 1;
if (retained->sick_child_detected) {
if (had_healthy_child) {
/* Assume this is a transient error, even though it may not be. Leave
* the server up in case it is able to serve some requests or the
* problem will be resolved.
*/
retained->sick_child_detected = 0;
}
else if (child_bucket < num_buckets - 1) {
/* check for had_healthy_child up to the last child bucket */
return;
}
else {
/* looks like a basket case, as no child ever fully initialized; give up.
*/
retained->mpm->shutdown_pending = 1;
child_fatal = 1;
ap_log_error(APLOG_MARK, APLOG_ALERT, 0,
ap_server_conf, APLOGNO(02325)
"A resource shortage or other unrecoverable failure "
"was encountered before any child process initialized "
"successfully... httpd is exiting!");
/* the child already logged the failure details */
return;
}
}
if (idle_thread_count > max_spare_threads / num_buckets) {
/* Kill off one child */
ap_mpm_podx_signal(all_buckets[child_bucket].pod,
AP_MPM_PODX_GRACEFUL);
retained->idle_spawn_rate[child_bucket] = 1;
}
else if (idle_thread_count < min_spare_threads / num_buckets) {
/* terminate the free list */
if (free_length == 0) { /* scoreboard is full, can't fork */
if (active_thread_count >= max_workers / num_buckets) {
/* no threads are "inactive" - starting, stopping, etc. */
/* have we reached MaxRequestWorkers, or just getting close? */
if (0 == idle_thread_count) {
if (!retained->maxclients_reported) {
/* only report this condition once */
ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(00286)
"server reached MaxRequestWorkers "
"setting, consider raising the "
"MaxRequestWorkers setting");
retained->maxclients_reported = 1;
}
} else {
if (!retained->near_maxclients_reported) {
ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(00287)
"server is within MinSpareThreads of "
"MaxRequestWorkers, consider raising the "
"MaxRequestWorkers setting");
retained->near_maxclients_reported = 1;
}
}
}
else {
ap_log_error(APLOG_MARK, APLOG_ERR, 0,
ap_server_conf, APLOGNO(00288)
"scoreboard is full, not at MaxRequestWorkers");
}
retained->idle_spawn_rate[child_bucket] = 1;
}
else {
if (free_length > retained->idle_spawn_rate[child_bucket]) {
free_length = retained->idle_spawn_rate[child_bucket];
}
if (retained->idle_spawn_rate[child_bucket] >= 8) {
ap_log_error(APLOG_MARK, APLOG_INFO, 0,
ap_server_conf, APLOGNO(00289)
"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,
idle_thread_count, total_non_dead);
}
for (i = 0; i < free_length; ++i) {
make_child(ap_server_conf, free_slots[i], child_bucket);
}
/* the next time around we want to spawn twice as many if this
* wasn't good enough, but not if we've just done a graceful
*/
if (retained->hold_off_on_exponential_spawning) {
--retained->hold_off_on_exponential_spawning;
}
else if (retained->idle_spawn_rate[child_bucket]
< MAX_SPAWN_RATE / num_buckets) {
retained->idle_spawn_rate[child_bucket] *= 2;
}
}
}
else {
retained->idle_spawn_rate[child_bucket] = 1;
}
}
static void server_main_loop(int remaining_children_to_start)
{
int num_buckets = retained->mpm->num_buckets;
int successive_kills = 0;
ap_generation_t old_gen;
int child_slot;
apr_exit_why_e exitwhy;
int status, processed_status;
apr_proc_t pid;
int i;
while (!retained->mpm->restart_pending && !retained->mpm->shutdown_pending) {
ap_wait_or_timeout(&exitwhy, &status, &pid, pconf, ap_server_conf);
if (pid.pid != -1) {
processed_status = ap_process_child_status(&pid, exitwhy, status);
child_slot = ap_find_child_by_pid(&pid);
if (processed_status == APEXIT_CHILDFATAL) {
/* fix race condition found in PR 39311
* A child created at the same time as a graceful happens
* can find the lock missing and create a fatal error.
* It is not fatal for the last generation to be in this state.
*/
if (child_slot < 0
|| ap_get_scoreboard_process(child_slot)->generation
== retained->mpm->my_generation) {
retained->mpm->shutdown_pending = 1;
child_fatal = 1;
return;
}
else {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, ap_server_conf, APLOGNO(00290)
"Ignoring fatal error in child of previous "
"generation (pid %ld).",
(long)pid.pid);
retained->sick_child_detected = 1;
}
}
else if (processed_status == APEXIT_CHILDSICK) {
/* tell perform_idle_server_maintenance to check into this
* on the next timer pop
*/
retained->sick_child_detected = 1;
}
/* non-fatal death... note that it's gone in the scoreboard. */
if (child_slot >= 0) {
process_score *ps;
for (i = 0; i < threads_per_child; i++)
ap_update_child_status_from_indexes(child_slot, i,
SERVER_DEAD, NULL);
worker_note_child_killed(child_slot, 0, 0);
ps = &ap_scoreboard_image->parent[child_slot];
ps->quiescing = 0;
if (processed_status == APEXIT_CHILDSICK) {
/* resource shortage, minimize the fork rate */
retained->idle_spawn_rate[child_slot % num_buckets] = 1;
}
else if (remaining_children_to_start
&& child_slot < ap_daemons_limit) {
/* we're still doing a 1-for-1 replacement of dead
* children with new children
*/
make_child(ap_server_conf, child_slot,
child_slot % num_buckets);
--remaining_children_to_start;
}
}
else if (ap_unregister_extra_mpm_process(pid.pid, &old_gen) == 1) {
worker_note_child_killed(-1, /* already out of the scoreboard */
pid.pid, old_gen);
if (processed_status == APEXIT_CHILDSICK
&& old_gen == retained->mpm->my_generation) {
/* resource shortage, minimize the fork rate */
for (i = 0; i < num_buckets; i++) {
retained->idle_spawn_rate[i] = 1;
}
}
#if APR_HAS_OTHER_CHILD
}
else if (apr_proc_other_child_alert(&pid, APR_OC_REASON_DEATH,
status) == 0) {
/* handled */
#endif
}
else if (retained->mpm->was_graceful) {
/* Great, we've probably just lost a slot in the
* scoreboard. Somehow we don't know about this child.
*/
ap_log_error(APLOG_MARK, APLOG_WARNING, 0,
ap_server_conf, APLOGNO(00291)
"long lost child came home! (pid %ld)",
(long)pid.pid);
}
/* Don't perform idle maintenance when a child dies,
* only do it when there's a timeout. Remember only a
* finite number of children can die, and it's pretty
* pathological for a lot to die suddenly. If a child is
* killed by a signal (faulting) we want to restart it ASAP
* though, up to 3 successive faults or we stop this until
* a timeout happens again (to avoid the flood of fork()ed
* processes that keep being killed early).
*/
if (child_slot < 0 || !APR_PROC_CHECK_SIGNALED(exitwhy)) {
continue;
}
if (++successive_kills >= 3) {
if (successive_kills % 10 == 3) {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0,
ap_server_conf, APLOGNO(10393)
"children are killed successively!");
}
continue;
}
++remaining_children_to_start;
}
else {
successive_kills = 0;
}
if (remaining_children_to_start) {
/* we hit a 1 second timeout in which none of the previous
* generation of children needed to be reaped... so assume
* they're all done, and pick up the slack if any is left.
*/
startup_children(remaining_children_to_start);
remaining_children_to_start = 0;
/* In any event we really shouldn't do the code below because
* few of the servers we just started are in the IDLE state
* yet, so we'd mistakenly create an extra server.
*/
continue;
}
for (i = 0; i < num_buckets; i++) {
perform_idle_server_maintenance(i);
}
}
}
static int worker_run(apr_pool_t *_pconf, apr_pool_t *plog, server_rec *s)
{
int num_buckets = retained->mpm->num_buckets;
int remaining_children_to_start;
int i;
ap_log_pid(pconf, ap_pid_fname);
if (!retained->mpm->was_graceful) {
if (ap_run_pre_mpm(s->process->pool, SB_SHARED) != OK) {
retained->mpm->mpm_state = AP_MPMQ_STOPPING;
return !OK;
}
/* fix the generation number in the global score; we just got a new,
* cleared scoreboard
*/
ap_scoreboard_image->global->running_generation = retained->mpm->my_generation;
}
ap_unixd_mpm_set_signals(pconf, one_process);
/* Don't thrash since num_buckets depends on the
* system and the number of online CPU cores...
*/
if (ap_daemons_limit < num_buckets)
ap_daemons_limit = num_buckets;
if (ap_daemons_to_start < num_buckets)
ap_daemons_to_start = num_buckets;
/* We want to create as much children at a time as the number of buckets,
* so to optimally accept connections (evenly distributed across buckets).
* Thus min_spare_threads should at least maintain num_buckets children,
* and max_spare_threads allow num_buckets more children w/o triggering
* immediately (e.g. num_buckets idle threads margin, one per bucket).
*/
if (min_spare_threads < threads_per_child * (num_buckets - 1) + num_buckets)
min_spare_threads = threads_per_child * (num_buckets - 1) + num_buckets;
if (max_spare_threads < min_spare_threads + (threads_per_child + 1) * num_buckets)
max_spare_threads = min_spare_threads + (threads_per_child + 1) * num_buckets;
/* If we're doing a graceful_restart then we're going to see a lot
* of children exiting immediately when we get into the main loop
* below (because we just sent them AP_SIG_GRACEFUL). This happens pretty
* rapidly... and for each one that exits we may start a new one, until
* there are at least min_spare_threads idle threads, counting across
* all children. But we may be permitted to start more children than
* that, so we'll just keep track of how many we're
* supposed to start up without the 1 second penalty between each fork.
*/
remaining_children_to_start = ap_daemons_to_start;
if (remaining_children_to_start > ap_daemons_limit) {
remaining_children_to_start = ap_daemons_limit;
}
if (!retained->mpm->was_graceful) {
startup_children(remaining_children_to_start);
remaining_children_to_start = 0;
}
else {
/* give the system some time to recover before kicking into
* exponential mode */
retained->hold_off_on_exponential_spawning = 10;
}
ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00292)
"%s configured -- resuming normal operations",
ap_get_server_description());
ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf, APLOGNO(00293)
"Server built: %s", ap_get_server_built());
ap_log_command_line(plog, s);
ap_log_mpm_common(s);
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00294)
"Accept mutex: %s (default: %s)",
(all_buckets[0].mutex)
? apr_proc_mutex_name(all_buckets[0].mutex)
: "none",
apr_proc_mutex_defname());
retained->mpm->mpm_state = AP_MPMQ_RUNNING;
server_main_loop(remaining_children_to_start);
retained->mpm->mpm_state = AP_MPMQ_STOPPING;
if (retained->mpm->shutdown_pending && retained->mpm->is_ungraceful) {
/* Time to shut down:
* Kill child processes, tell them to call child_exit, etc...
*/
for (i = 0; i < num_buckets; i++) {
ap_mpm_podx_killpg(all_buckets[i].pod, ap_daemons_limit,
AP_MPM_PODX_RESTART);
}
ap_reclaim_child_processes(1, /* Start with SIGTERM */
worker_note_child_killed);
if (!child_fatal) {
/* cleanup pid file on normal shutdown */
ap_remove_pid(pconf, ap_pid_fname);
ap_log_error(APLOG_MARK, APLOG_NOTICE, 0,
ap_server_conf, APLOGNO(00295) "caught SIGTERM, shutting down");
}
return DONE;
}
if (retained->mpm->shutdown_pending) {
/* Time to gracefully shut down:
* Kill child processes, tell them to call child_exit, etc...
*/
int active_children;
int index;
apr_time_t cutoff = 0;
/* Close our listeners, and then ask our children to do same */
ap_close_listeners();
for (i = 0; i < num_buckets; i++) {
ap_mpm_podx_killpg(all_buckets[i].pod, ap_daemons_limit,
AP_MPM_PODX_GRACEFUL);
}
ap_relieve_child_processes(worker_note_child_killed);
if (!child_fatal) {
/* cleanup pid file on normal shutdown */
ap_remove_pid(pconf, ap_pid_fname);
ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00296)
"caught " AP_SIG_GRACEFUL_STOP_STRING
", shutting down gracefully");
}
if (ap_graceful_shutdown_timeout) {
cutoff = apr_time_now() +
apr_time_from_sec(ap_graceful_shutdown_timeout);
}
/* Don't really exit until each child has finished */
retained->mpm->shutdown_pending = 0;
do {
/* Pause for a second */
apr_sleep(apr_time_from_sec(1));
/* Relieve any children which have now exited */
ap_relieve_child_processes(worker_note_child_killed);
active_children = 0;
for (index = 0; index < ap_daemons_limit; ++index) {
if (ap_mpm_safe_kill(MPM_CHILD_PID(index), 0) == APR_SUCCESS) {
active_children = 1;
/* Having just one child is enough to stay around */
break;
}
}
} while (!retained->mpm->shutdown_pending && active_children &&
(!ap_graceful_shutdown_timeout || apr_time_now() < cutoff));
/* We might be here because we received SIGTERM, either
* way, try and make sure that all of our processes are
* really dead.
*/
for (i = 0; i < num_buckets; i++) {
ap_mpm_podx_killpg(all_buckets[i].pod, ap_daemons_limit,
AP_MPM_PODX_RESTART);
}
ap_reclaim_child_processes(1, worker_note_child_killed);
return DONE;
}
/* we've been told to restart */
if (one_process) {
/* not worth thinking about */
return DONE;
}
/* advance to the next generation */
/* XXX: we really need to make sure this new generation number isn't in
* use by any of the children.
*/
++retained->mpm->my_generation;
ap_scoreboard_image->global->running_generation = retained->mpm->my_generation;
if (!retained->mpm->is_ungraceful) {
ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00297)
AP_SIG_GRACEFUL_STRING " received. Doing graceful restart");
/* wake up the children...time to die. But we'll have more soon */
for (i = 0; i < num_buckets; i++) {
ap_mpm_podx_killpg(all_buckets[i].pod, ap_daemons_limit,
AP_MPM_PODX_GRACEFUL);
}
/* This is mostly for debugging... so that we know what is still
* gracefully dealing with existing request.
*/
}
else {
/* Kill 'em all. Since the child acts the same on the parents SIGTERM
* and a SIGHUP, we may as well use the same signal, because some user
* pthreads are stealing signals from us left and right.
*/
for (i = 0; i < num_buckets; i++) {
ap_mpm_podx_killpg(all_buckets[i].pod, ap_daemons_limit,
AP_MPM_PODX_RESTART);
}
ap_reclaim_child_processes(1, /* Start with SIGTERM */
worker_note_child_killed);
ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00298)
"SIGHUP received. Attempting to restart");
}
return OK;
}
/* 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 worker_open_logs(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s)
{
int startup = 0;
int level_flags = 0;
int num_buckets = 0;
ap_listen_rec **listen_buckets;
apr_status_t rv;
char id[16];
int i;
pconf = p;
/* the reverse of pre_config, we want this only the first time around */
if (retained->mpm->module_loads == 1) {
startup = 1;
level_flags |= APLOG_STARTUP;
}
if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) {
ap_log_error(APLOG_MARK, APLOG_ALERT | level_flags, 0,
(startup ? NULL : s),
"no listening sockets available, shutting down");
return !OK;
}
if (one_process) {
num_buckets = 1;
}
else if (retained->mpm->was_graceful) {
/* Preserve the number of buckets on graceful restarts. */
num_buckets = retained->mpm->num_buckets;
}
if ((rv = ap_duplicate_listeners(pconf, ap_server_conf,
&listen_buckets, &num_buckets))) {
ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv,
(startup ? NULL : s),
"could not duplicate listeners");
return !OK;
}
all_buckets = apr_pcalloc(pconf, num_buckets * sizeof(*all_buckets));
for (i = 0; i < num_buckets; i++) {
if (!one_process && /* no POD in one_process mode */
(rv = ap_mpm_podx_open(pconf, &all_buckets[i].pod))) {
ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv,
(startup ? NULL : s),
"could not open pipe-of-death");
return !OK;
}
/* Initialize cross-process accept lock (safe accept needed only) */
if ((rv = SAFE_ACCEPT((apr_snprintf(id, sizeof id, "%i", i),
ap_proc_mutex_create(&all_buckets[i].mutex,
NULL, AP_ACCEPT_MUTEX_TYPE,
id, s, pconf, 0))))) {
ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv,
(startup ? NULL : s),
"could not create accept mutex");
return !OK;
}
all_buckets[i].listeners = listen_buckets[i];
}
if (retained->mpm->max_buckets < num_buckets) {
int new_max, *new_ptr;
new_max = retained->mpm->max_buckets * 2;
if (new_max < num_buckets) {
new_max = num_buckets;
}
new_ptr = (int *)apr_palloc(ap_pglobal, new_max * sizeof(int));
if (retained->idle_spawn_rate) /* NULL at startup */
memcpy(new_ptr, retained->idle_spawn_rate,
retained->mpm->num_buckets * sizeof(int));
retained->idle_spawn_rate = new_ptr;
retained->mpm->max_buckets = new_max;
}
if (retained->mpm->num_buckets < num_buckets) {
int rate_max = 1;
/* If new buckets are added, set their idle spawn rate to
* the highest so far, so that they get filled as quickly
* as the existing ones.
*/
for (i = 0; i < retained->mpm->num_buckets; i++) {
if (rate_max < retained->idle_spawn_rate[i]) {
rate_max = retained->idle_spawn_rate[i];
}
}
for (/* up to date i */; i < num_buckets; i++) {
retained->idle_spawn_rate[i] = rate_max;
}
}
retained->mpm->num_buckets = num_buckets;
return OK;
}
static int worker_pre_config(apr_pool_t *pconf, apr_pool_t *plog,
apr_pool_t *ptemp)
{
int no_detach, debug, foreground;
apr_status_t rv;
const char *userdata_key = "mpm_worker_module";
debug = ap_exists_config_define("DEBUG");
if (debug) {
foreground = one_process = 1;
no_detach = 0;
}
else {
one_process = ap_exists_config_define("ONE_PROCESS");
no_detach = ap_exists_config_define("NO_DETACH");
foreground = ap_exists_config_define("FOREGROUND");
}
ap_mutex_register(pconf, AP_ACCEPT_MUTEX_TYPE, NULL, APR_LOCK_DEFAULT, 0);
retained = ap_retained_data_get(userdata_key);
if (!retained) {
retained = ap_retained_data_create(userdata_key, sizeof(*retained));
retained->mpm = ap_unixd_mpm_get_retained_data();
}
retained->mpm->mpm_state = AP_MPMQ_STARTING;
if (retained->mpm->baton != retained) {
retained->mpm->was_graceful = 0;
retained->mpm->baton = retained;
}
++retained->mpm->module_loads;
/* sigh, want this only the second time around */
if (retained->mpm->module_loads == 2) {
if (!one_process && !foreground) {
/* before we detach, setup crash handlers to log to errorlog */
ap_fatal_signal_setup(ap_server_conf, pconf);
rv = apr_proc_detach(no_detach ? APR_PROC_DETACH_FOREGROUND
: APR_PROC_DETACH_DAEMONIZE);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL, APLOGNO(00299)
"apr_proc_detach failed");
return HTTP_INTERNAL_SERVER_ERROR;
}
}
}
parent_pid = ap_my_pid = getpid();
ap_listen_pre_config();
ap_daemons_to_start = DEFAULT_START_DAEMON;
min_spare_threads = DEFAULT_MIN_FREE_DAEMON * DEFAULT_THREADS_PER_CHILD;
max_spare_threads = DEFAULT_MAX_FREE_DAEMON * DEFAULT_THREADS_PER_CHILD;
server_limit = DEFAULT_SERVER_LIMIT;
thread_limit = DEFAULT_THREAD_LIMIT;
ap_daemons_limit = server_limit;
threads_per_child = DEFAULT_THREADS_PER_CHILD;
max_workers = ap_daemons_limit * threads_per_child;
had_healthy_child = 0;
ap_extended_status = 0;
return OK;
}
static int worker_check_config(apr_pool_t *p, apr_pool_t *plog,
apr_pool_t *ptemp, server_rec *s)
{
int startup = 0;
/* the reverse of pre_config, we want this only the first time around */
if (retained->mpm->module_loads == 1) {
startup = 1;
}
if (server_limit > MAX_SERVER_LIMIT) {
if (startup) {
ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00300)
"WARNING: ServerLimit of %d exceeds compile-time "
"limit of %d servers, decreasing to %d.",
server_limit, MAX_SERVER_LIMIT, MAX_SERVER_LIMIT);
} else {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00301)
"ServerLimit of %d exceeds compile-time limit "
"of %d, decreasing to match",
server_limit, MAX_SERVER_LIMIT);
}
server_limit = MAX_SERVER_LIMIT;
}
else if (server_limit < 1) {
if (startup) {
ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00302)
"WARNING: ServerLimit of %d not allowed, "
"increasing to 1.", server_limit);
} else {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00303)
"ServerLimit of %d not allowed, increasing to 1",
server_limit);
}
server_limit = 1;
}
/* you cannot change ServerLimit across a restart; ignore
* any such attempts
*/
if (!retained->first_server_limit) {
retained->first_server_limit = server_limit;
}
else if (server_limit != retained->first_server_limit) {
/* don't need a startup console version here */
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00304)
"changing ServerLimit to %d from original value of %d "
"not allowed during restart",
server_limit, retained->first_server_limit);
server_limit = retained->first_server_limit;
}
if (thread_limit > MAX_THREAD_LIMIT) {
if (startup) {
ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00305)
"WARNING: ThreadLimit of %d exceeds compile-time "
"limit of %d threads, decreasing to %d.",
thread_limit, MAX_THREAD_LIMIT, MAX_THREAD_LIMIT);
} else {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00306)
"ThreadLimit of %d exceeds compile-time limit "
"of %d, decreasing to match",
thread_limit, MAX_THREAD_LIMIT);
}
thread_limit = MAX_THREAD_LIMIT;
}
else if (thread_limit < 1) {
if (startup) {
ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00307)
"WARNING: ThreadLimit of %d not allowed, "
"increasing to 1.", thread_limit);
} else {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00308)
"ThreadLimit of %d not allowed, increasing to 1",
thread_limit);
}
thread_limit = 1;
}
/* you cannot change ThreadLimit across a restart; ignore
* any such attempts
*/
if (!retained->first_thread_limit) {
retained->first_thread_limit = thread_limit;
}
else if (thread_limit != retained->first_thread_limit) {
/* don't need a startup console version here */
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00309)
"changing ThreadLimit to %d from original value of %d "
"not allowed during restart",
thread_limit, retained->first_thread_limit);
thread_limit = retained->first_thread_limit;
}
if (threads_per_child > thread_limit) {
if (startup) {
ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00310)
"WARNING: ThreadsPerChild of %d exceeds ThreadLimit "
"of %d threads, decreasing to %d. "
"To increase, please see the ThreadLimit directive.",
threads_per_child, thread_limit, thread_limit);
} else {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00311)
"ThreadsPerChild of %d exceeds ThreadLimit "
"of %d, decreasing to match",
threads_per_child, thread_limit);
}
threads_per_child = thread_limit;
}
else if (threads_per_child < 1) {
if (startup) {
ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00312)
"WARNING: ThreadsPerChild of %d not allowed, "
"increasing to 1.", threads_per_child);
} else {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00313)
"ThreadsPerChild of %d not allowed, increasing to 1",
threads_per_child);
}
threads_per_child = 1;
}
if (max_workers < threads_per_child) {
if (startup) {
ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00314)
"WARNING: MaxRequestWorkers of %d is less than "
"ThreadsPerChild of %d, increasing to %d. "
"MaxRequestWorkers must be at least as large "
"as the number of threads in a single server.",
max_workers, threads_per_child, threads_per_child);
} else {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00315)
"MaxRequestWorkers of %d is less than ThreadsPerChild "
"of %d, increasing to match",
max_workers, threads_per_child);
}
max_workers = threads_per_child;
}
ap_daemons_limit = max_workers / threads_per_child;
if (max_workers % threads_per_child) {
int tmp_max_workers = ap_daemons_limit * threads_per_child;
if (startup) {
ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00316)
"WARNING: MaxRequestWorkers of %d is not an integer "
"multiple of ThreadsPerChild of %d, decreasing to nearest "
"multiple %d, for a maximum of %d servers.",
max_workers, threads_per_child, tmp_max_workers,
ap_daemons_limit);
} else {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00317)
"MaxRequestWorkers of %d is not an integer multiple of "
"ThreadsPerChild of %d, decreasing to nearest "
"multiple %d", max_workers, threads_per_child,
tmp_max_workers);
}
max_workers = tmp_max_workers;
}
if (ap_daemons_limit > server_limit) {
if (startup) {
ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00318)
"WARNING: MaxRequestWorkers of %d would require %d "
"servers and would exceed ServerLimit of %d, decreasing to %d. "
"To increase, please see the ServerLimit directive.",
max_workers, ap_daemons_limit, server_limit,
server_limit * threads_per_child);
} else {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00319)
"MaxRequestWorkers of %d would require %d servers and "
"exceed ServerLimit of %d, decreasing to %d",
max_workers, ap_daemons_limit, server_limit,
server_limit * threads_per_child);
}
ap_daemons_limit = server_limit;
}
/* ap_daemons_to_start > ap_daemons_limit checked in worker_run() */
if (ap_daemons_to_start < 1) {
if (startup) {
ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00320)
"WARNING: StartServers of %d not allowed, "
"increasing to 1.", ap_daemons_to_start);
} else {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00321)
"StartServers of %d not allowed, increasing to 1",
ap_daemons_to_start);
}
ap_daemons_to_start = 1;
}
if (min_spare_threads < 1) {
if (startup) {
ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00322)
"WARNING: MinSpareThreads of %d not allowed, "
"increasing to 1 to avoid almost certain server failure. "
"Please read the documentation.", min_spare_threads);
} else {
ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00323)
"MinSpareThreads of %d not allowed, increasing to 1",
min_spare_threads);
}
min_spare_threads = 1;
}
/* max_spare_threads < min_spare_threads + threads_per_child
* checked in worker_run()
*/
return OK;
}
static void worker_hooks(apr_pool_t *p)
{
/* Our open_logs hook function must run before the core's, or stderr
* will be redirected to a file, and the messages won't print to the
* console.
*/
static const char *const aszSucc[] = {"core.c", NULL};
one_process = 0;
ap_hook_open_logs(worker_open_logs, NULL, aszSucc, APR_HOOK_REALLY_FIRST);
/* we need to set the MPM state before other pre-config hooks use MPM query
* to retrieve it, so register as REALLY_FIRST
*/
ap_hook_pre_config(worker_pre_config, NULL, NULL, APR_HOOK_REALLY_FIRST);
ap_hook_check_config(worker_check_config, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_mpm(worker_run, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_mpm_query(worker_query, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_mpm_get_name(worker_get_name, NULL, NULL, APR_HOOK_MIDDLE);
}
static const char *set_daemons_to_start(cmd_parms *cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
ap_daemons_to_start = atoi(arg);
return NULL;
}
static const char *set_min_spare_threads(cmd_parms *cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
min_spare_threads = atoi(arg);
return NULL;
}
static const char *set_max_spare_threads(cmd_parms *cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
max_spare_threads = atoi(arg);
return NULL;
}
static const char *set_max_workers (cmd_parms *cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
if (!strcasecmp(cmd->cmd->name, "MaxClients")) {
ap_log_error(APLOG_MARK, APLOG_INFO, 0, NULL, APLOGNO(00324)
"MaxClients is deprecated, use MaxRequestWorkers "
"instead.");
}
max_workers = atoi(arg);
return NULL;
}
static const char *set_threads_per_child (cmd_parms *cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
threads_per_child = atoi(arg);
return NULL;
}
static const char *set_server_limit (cmd_parms *cmd, void *dummy, const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
server_limit = atoi(arg);
return NULL;
}
static const char *set_thread_limit (cmd_parms *cmd, void *dummy, const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
thread_limit = atoi(arg);
return NULL;
}
static const command_rec worker_cmds[] = {
LISTEN_COMMANDS,
AP_INIT_TAKE1("StartServers", set_daemons_to_start, NULL, RSRC_CONF,
"Number of child processes launched at server startup"),
AP_INIT_TAKE1("MinSpareThreads", set_min_spare_threads, NULL, RSRC_CONF,
"Minimum number of idle threads, to handle request spikes"),
AP_INIT_TAKE1("MaxSpareThreads", set_max_spare_threads, NULL, RSRC_CONF,
"Maximum number of idle threads"),
AP_INIT_TAKE1("MaxRequestWorkers", set_max_workers, NULL, RSRC_CONF,
"Maximum number of threads alive at the same time"),
AP_INIT_TAKE1("MaxClients", set_max_workers, NULL, RSRC_CONF,
"Deprecated name of MaxRequestWorkers"),
AP_INIT_TAKE1("ThreadsPerChild", set_threads_per_child, NULL, RSRC_CONF,
"Number of threads each child creates"),
AP_INIT_TAKE1("ServerLimit", set_server_limit, NULL, RSRC_CONF,
"Maximum number of child processes for this run of Apache"),
AP_INIT_TAKE1("ThreadLimit", set_thread_limit, NULL, RSRC_CONF,
"Maximum number of worker threads per child process for this run of Apache - Upper limit for ThreadsPerChild"),
AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND,
{ NULL }
};
AP_DECLARE_MODULE(mpm_worker) = {
MPM20_MODULE_STUFF,
NULL, /* hook to run before apache parses args */
NULL, /* create per-directory config structure */
NULL, /* merge per-directory config structures */
NULL, /* create per-server config structure */
NULL, /* merge per-server config structures */
worker_cmds, /* command apr_table_t */
worker_hooks /* register_hooks */
};
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