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Posted to cvs@httpd.apache.org by br...@apache.org on 2002/04/12 00:33:57 UTC
cvs commit: httpd-2.0/server/mpm/experimental/leader leader.c mpm.h
brianp 02/04/11 15:33:57
Added: server/mpm/experimental/leader leader.c mpm.h
Log:
Initial check-in of leader-follower MPM code, derived from worker
Revision Changes Path
1.1 httpd-2.0/server/mpm/experimental/leader/leader.c
Index: leader.c
===================================================================
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2000-2002 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
* Portions of this software are based upon public domain software
* originally written at the National Center for Supercomputing Applications,
* University of Illinois, Urbana-Champaign.
*/
/* 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_cond.h"
#include "apr_thread_mutex.h"
#include "apr_proc_mutex.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 Leader/Follower MPM requires APR threads, but they are unavailable.
#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 "mpm_default.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
*/
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 server_limit = DEFAULT_SERVER_LIMIT;
static int first_server_limit;
static int thread_limit = DEFAULT_THREAD_LIMIT;
static int first_thread_limit;
static int changed_limit_at_restart;
static int dying = 0;
static int workers_may_exit = 0;
static int start_thread_may_exit = 0;
static int requests_this_child;
static int num_listensocks = 0;
static int resource_shortage = 0;
/* 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;
int child_num_arg;
apr_threadattr_t *threadattr;
} thread_starter;
#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;
static ap_pod_t *pod;
/* *Non*-shared http_main globals... */
server_rec *ap_server_conf;
/* This 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 pid_t ap_my_pid; /* Linux getpid() doesn't work except in main
thread. Use this instead */
static pid_t parent_pid;
/* Locks for accept serialization */
static apr_proc_mutex_t *accept_mutex;
#ifdef SINGLE_LISTEN_UNSERIALIZED_ACCEPT
#define SAFE_ACCEPT(stmt) (ap_listeners->next ? (stmt) : APR_SUCCESS)
#else
#define SAFE_ACCEPT(stmt) (stmt)
#endif
/* Structure used to wake up an idle worker thread
*/
typedef struct {
apr_thread_cond_t *cond;
apr_thread_mutex_t *mutex;
} worker_wakeup_info;
/* Structure used to hold a stack of idle worker threads
*/
typedef struct {
apr_thread_mutex_t *mutex;
int no_listener;
worker_wakeup_info **stack;
apr_size_t nelts;
apr_size_t nalloc;
} worker_stack;
static worker_stack* worker_stack_create(apr_pool_t *pool, apr_size_t max)
{
apr_status_t rv;
worker_stack *stack = (worker_stack *)apr_palloc(pool, sizeof(*stack));
if ((rv = apr_thread_mutex_create(&stack->mutex, APR_THREAD_MUTEX_DEFAULT,
pool)) != APR_SUCCESS) {
return NULL;
}
stack->no_listener = 1;
stack->nelts = 0;
stack->nalloc = max;
stack->stack =
(worker_wakeup_info **)apr_palloc(pool, stack->nalloc *
sizeof(worker_wakeup_info *));
return stack;
}
static apr_status_t worker_stack_wait(worker_stack *stack,
worker_wakeup_info *wakeup)
{
apr_status_t rv;
if ((rv = apr_thread_mutex_lock(stack->mutex)) != APR_SUCCESS) {
return rv;
}
if (stack->no_listener) {
/* this thread should become the new listener immediately */
stack->no_listener = 0;
if ((rv = apr_thread_mutex_unlock(stack->mutex)) != APR_SUCCESS) {
return rv;
}
return APR_SUCCESS;
}
else {
/* push this thread onto the stack of idle workers, and block
* on the condition variable until awoken
*/
if (stack->nelts == stack->nalloc) {
return APR_ENOSPC;
}
stack->stack[stack->nelts++] = wakeup;
if ((rv = apr_thread_mutex_unlock(stack->mutex)) != APR_SUCCESS) {
return rv;
}
if ((rv = apr_thread_cond_wait(wakeup->cond, wakeup->mutex)) !=
APR_SUCCESS) {
return rv;
}
return APR_SUCCESS;
}
}
static apr_status_t worker_stack_awaken_next(worker_stack *stack)
{
apr_status_t rv;
if ((rv = apr_thread_mutex_lock(stack->mutex)) != APR_SUCCESS) {
return rv;
}
if (stack->nelts) {
worker_wakeup_info *wakeup = stack->stack[--stack->nelts];
if ((rv = apr_thread_mutex_unlock(stack->mutex)) != APR_SUCCESS) {
return rv;
}
if ((rv = apr_thread_cond_signal(wakeup->cond)) != APR_SUCCESS) {
apr_thread_mutex_unlock(stack->mutex);
return rv;
}
}
else {
stack->no_listener = 1;
if ((rv = apr_thread_mutex_unlock(stack->mutex)) != APR_SUCCESS) {
return rv;
}
}
return APR_SUCCESS;
}
static worker_stack *idle_worker_stack;
#define ST_INIT 0
#define ST_GRACEFUL 1
#define ST_UNGRACEFUL 2
static int terminate_mode = ST_INIT;
static void signal_threads(int mode)
{
int i;
if (terminate_mode == mode) {
return;
}
terminate_mode = mode;
workers_may_exit = 1;
for (i = 0; i < ap_threads_per_child; i++) {
(void)worker_stack_awaken_next(idle_worker_stack);
}
}
AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result)
{
switch(query_code){
case AP_MPMQ_MAX_DAEMON_USED:
*result = ap_max_daemons_limit;
return APR_SUCCESS;
case AP_MPMQ_IS_THREADED:
*result = AP_MPMQ_STATIC;
return APR_SUCCESS;
case AP_MPMQ_IS_FORKED:
*result = AP_MPMQ_DYNAMIC;
return APR_SUCCESS;
case AP_MPMQ_HARD_LIMIT_DAEMONS:
*result = server_limit;
return APR_SUCCESS;
case AP_MPMQ_HARD_LIMIT_THREADS:
*result = thread_limit;
return APR_SUCCESS;
case AP_MPMQ_MAX_THREADS:
*result = ap_threads_per_child;
return APR_SUCCESS;
case AP_MPMQ_MIN_SPARE_DAEMONS:
*result = 0;
return APR_SUCCESS;
case AP_MPMQ_MIN_SPARE_THREADS:
*result = min_spare_threads;
return APR_SUCCESS;
case AP_MPMQ_MAX_SPARE_DAEMONS:
*result = 0;
return APR_SUCCESS;
case AP_MPMQ_MAX_SPARE_THREADS:
*result = max_spare_threads;
return APR_SUCCESS;
case AP_MPMQ_MAX_REQUESTS_DAEMON:
*result = ap_max_requests_per_child;
return APR_SUCCESS;
case AP_MPMQ_MAX_DAEMONS:
*result = ap_daemons_limit;
return APR_SUCCESS;
}
return APR_ENOTIMPL;
}
/* 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)
{
if (pchild) {
apr_pool_destroy(pchild);
}
exit(code);
}
/* handle all varieties of core dumping signals */
static void sig_coredump(int sig)
{
apr_filepath_set(ap_coredump_dir, pconf);
apr_signal(sig, SIG_DFL);
if (ap_my_pid == parent_pid) {
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE,
0, ap_server_conf,
"seg fault or similar nasty error detected "
"in the parent process");
/* XXX we can probably add some rudimentary cleanup code here,
* like getting rid of the pid file. If any additional bad stuff
* happens, we are protected from recursive errors taking down the
* system since this function is no longer the signal handler GLA
*/
}
kill(ap_my_pid, sig);
/* At this point we've got sig blocked, because we're still inside
* the signal handler. When we leave the signal handler it will
* be unblocked, and we'll take the signal... and coredump or whatever
* is appropriate for this particular Unix. In addition the parent
* will see the real signal we received -- whereas if we called
* abort() here, the parent would only see SIGABRT.
*/
}
static void just_die(int sig)
{
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;
/*
* 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,
* but we want to be able to start a shutdown/restart from other sources --
* 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(void)
{
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;
is_graceful = graceful;
}
static void sig_term(int sig)
{
ap_start_shutdown();
}
static void restart(int sig)
{
ap_start_restart(sig == AP_SIG_GRACEFUL);
}
static void set_signals(void)
{
#ifndef NO_USE_SIGACTION
struct sigaction sa;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
if (!one_process) {
sa.sa_handler = sig_coredump;
#if defined(SA_ONESHOT)
sa.sa_flags = SA_ONESHOT;
#elif defined(SA_RESETHAND)
sa.sa_flags = SA_RESETHAND;
#endif
if (sigaction(SIGSEGV, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
"sigaction(SIGSEGV)");
#ifdef SIGBUS
if (sigaction(SIGBUS, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
"sigaction(SIGBUS)");
#endif
#ifdef SIGABORT
if (sigaction(SIGABORT, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
"sigaction(SIGABORT)");
#endif
#ifdef SIGABRT
if (sigaction(SIGABRT, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
"sigaction(SIGABRT)");
#endif
#ifdef SIGILL
if (sigaction(SIGILL, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
"sigaction(SIGILL)");
#endif
sa.sa_flags = 0;
}
sa.sa_handler = sig_term;
if (sigaction(SIGTERM, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
"sigaction(SIGTERM)");
#ifdef SIGINT
if (sigaction(SIGINT, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
"sigaction(SIGINT)");
#endif
#ifdef SIGXCPU
sa.sa_handler = SIG_DFL;
if (sigaction(SIGXCPU, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
"sigaction(SIGXCPU)");
#endif
#ifdef SIGXFSZ
sa.sa_handler = SIG_DFL;
if (sigaction(SIGXFSZ, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
"sigaction(SIGXFSZ)");
#endif
#ifdef SIGPIPE
sa.sa_handler = SIG_IGN;
if (sigaction(SIGPIPE, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
"sigaction(SIGPIPE)");
#endif
/* we want to ignore HUPs and AP_SIG_GRACEFUL while we're busy
* processing one */
sigaddset(&sa.sa_mask, SIGHUP);
sigaddset(&sa.sa_mask, AP_SIG_GRACEFUL);
sa.sa_handler = restart;
if (sigaction(SIGHUP, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
"sigaction(SIGHUP)");
if (sigaction(AP_SIG_GRACEFUL, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
"sigaction(" AP_SIG_GRACEFUL_STRING ")");
#else
if (!one_process) {
apr_signal(SIGSEGV, sig_coredump);
#ifdef SIGBUS
apr_signal(SIGBUS, sig_coredump);
#endif /* SIGBUS */
#ifdef SIGABORT
apr_signal(SIGABORT, sig_coredump);
#endif /* SIGABORT */
#ifdef SIGABRT
apr_signal(SIGABRT, sig_coredump);
#endif /* SIGABRT */
#ifdef SIGILL
apr_signal(SIGILL, sig_coredump);
#endif /* SIGILL */
#ifdef SIGXCPU
apr_signal(SIGXCPU, SIG_DFL);
#endif /* SIGXCPU */
#ifdef SIGXFSZ
apr_signal(SIGXFSZ, SIG_DFL);
#endif /* SIGXFSZ */
}
apr_signal(SIGTERM, sig_term);
#ifdef SIGHUP
apr_signal(SIGHUP, restart);
#endif /* SIGHUP */
#ifdef AP_SIG_GRACEFUL
apr_signal(AP_SIG_GRACEFUL, restart);
#endif /* AP_SIG_GRACEFUL */
#ifdef SIGPIPE
apr_signal(SIGPIPE, SIG_IGN);
#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?
*/
{
return workers_may_exit;
}
/*****************************************************************
* Child process main loop.
*/
static void process_socket(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);
int csd;
ap_sb_handle_t *sbh;
ap_create_sb_handle(&sbh, p, my_child_num, my_thread_num);
apr_os_sock_get(&csd, sock);
if (csd >= FD_SETSIZE) {
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, NULL,
"new file descriptor %d is too large; you probably need "
"to rebuild Apache with a larger FD_SETSIZE "
"(currently %d)",
csd, FD_SETSIZE);
apr_socket_close(sock);
return;
}
current_conn = ap_run_create_connection(p, ap_server_conf, sock,
conn_id, sbh, bucket_alloc);
if (current_conn) {
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
"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) {
signal_threads(ST_GRACEFUL);
}
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
*/
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 *worker_thread(apr_thread_t *thd, void * dummy)
{
proc_info * ti = dummy;
int process_slot = ti->pid;
int thread_slot = ti->tid;
apr_pool_t *tpool = apr_thread_pool_get(thd);
void *csd = NULL;
apr_allocator_t *allocator;
apr_pool_t *ptrans; /* Pool for per-transaction stuff */
apr_bucket_alloc_t *bucket_alloc;
int n;
apr_pollfd_t *pollset;
apr_status_t rv;
ap_listen_rec *lr, *last_lr = ap_listeners;
worker_wakeup_info *wakeup;
int is_listener;
ap_update_child_status_from_indexes(process_slot, thread_slot, SERVER_STARTING, NULL);
free(ti);
apr_allocator_create(&allocator);
apr_pool_create_ex(&ptrans, NULL, NULL, allocator);
apr_allocator_set_owner(allocator, ptrans);
bucket_alloc = apr_bucket_alloc_create(tpool);
wakeup = (worker_wakeup_info *)apr_palloc(tpool, sizeof(*wakeup));
if ((rv = apr_thread_cond_create(&wakeup->cond, tpool)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
"apr_thread_cond_create failed. Attempting to shutdown "
"process gracefully.");
signal_threads(ST_GRACEFUL);
goto done;
}
if ((rv = apr_thread_mutex_create(&wakeup->mutex, APR_THREAD_MUTEX_DEFAULT,
tpool)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
"apr_thread_mutex_create failed. Attempting to shutdown "
"process gracefully.");
signal_threads(ST_GRACEFUL);
goto done;
}
apr_thread_mutex_lock(wakeup->mutex);
apr_poll_setup(&pollset, num_listensocks, tpool);
for(lr = ap_listeners ; lr != NULL ; lr = lr->next)
apr_poll_socket_add(pollset, lr->sd, APR_POLLIN);
/* TODO: Switch to a system where threads reuse the results from earlier
poll calls - manoj */
is_listener = 0;
while (!workers_may_exit) {
ap_update_child_status_from_indexes(process_slot, thread_slot,
SERVER_READY, NULL);
if (!is_listener) {
/* Wait until it's our turn to become the listener */
if ((rv = worker_stack_wait(idle_worker_stack, wakeup)) !=
APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
"worker_stack_wait failed. Shutting down");
break;
}
is_listener = 1;
}
/* TODO: requests_this_child should be synchronized - aaron */
if (requests_this_child <= 0) {
check_infinite_requests();
}
if (workers_may_exit) break;
if ((rv = SAFE_ACCEPT(apr_proc_mutex_lock(accept_mutex)))
!= APR_SUCCESS) {
int level = APLOG_EMERG;
if (workers_may_exit) {
break;
}
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,
"apr_proc_mutex_lock failed. Attempting to shutdown "
"process gracefully.");
signal_threads(ST_GRACEFUL);
break; /* skip the lock release */
}
if (!ap_listeners->next) {
/* Only one listener, so skip the poll */
lr = ap_listeners;
}
else {
while (!workers_may_exit) {
apr_status_t ret;
apr_int16_t event;
ret = apr_poll(pollset, &n, -1);
if (ret != APR_SUCCESS) {
if (APR_STATUS_IS_EINTR(ret)) {
continue;
}
/* apr_poll() will only return errors in catastrophic
* circumstances. Let's try exiting gracefully, for now. */
ap_log_error(APLOG_MARK, APLOG_ERR, ret, (const server_rec *)
ap_server_conf, "apr_poll: (listen)");
signal_threads(ST_GRACEFUL);
}
if (workers_may_exit) break;
/* find a listener */
lr = last_lr;
do {
lr = lr->next;
if (lr == NULL) {
lr = ap_listeners;
}
/* XXX: Should we check for POLLERR? */
apr_poll_revents_get(&event, lr->sd, pollset);
if (event & APR_POLLIN) {
last_lr = lr;
goto got_fd;
}
} while (lr != last_lr);
}
}
got_fd:
if (!workers_may_exit) {
rv = lr->accept_func(&csd, lr, ptrans);
/* If we were interrupted for whatever reason, just start
* the main loop over again.
*/
if (APR_STATUS_IS_EINTR(rv)) {
continue;
}
if (rv == APR_EGENERAL) {
/* E[NM]FILE, ENOMEM, etc */
resource_shortage = 1;
signal_threads(ST_GRACEFUL);
}
if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(accept_mutex)))
!= APR_SUCCESS) {
int level = APLOG_EMERG;
if (workers_may_exit) {
break;
}
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,
"apr_proc_mutex_unlock failed. Attempting to "
"shutdown process gracefully.");
signal_threads(ST_GRACEFUL);
}
if (csd != NULL) {
is_listener = 0;
worker_stack_awaken_next(idle_worker_stack);
process_socket(ptrans, csd, process_slot,
thread_slot, bucket_alloc);
apr_pool_clear(ptrans);
requests_this_child--;
apr_socket_close(csd); /* Debug only */
}
}
else {
if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(accept_mutex)))
!= APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
"apr_proc_mutex_unlock failed. Attempting to "
"shutdown process gracefully.");
signal_threads(ST_GRACEFUL);
}
break;
}
}
done:
dying = 1;
ap_scoreboard_image->parent[process_slot].quiescing = 1;
worker_stack_awaken_next(idle_worker_stack);
ap_update_child_status_from_indexes(process_slot, thread_slot,
(dying) ? SERVER_DEAD : SERVER_GRACEFUL, (request_rec *) NULL);
apr_bucket_alloc_destroy(bucket_alloc);
apr_thread_exit(thd, APR_SUCCESS);
return NULL;
}
static int check_signal(int signum)
{
switch (signum) {
case SIGTERM:
case SIGINT:
return 1;
}
return 0;
}
/* 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 child_num_arg = ts->child_num_arg;
int my_child_num = child_num_arg;
proc_info *my_info;
apr_status_t rv;
int i;
int threads_created = 0;
int loops;
int prev_threads_created;
idle_worker_stack = worker_stack_create(pchild, ap_threads_per_child);
if (idle_worker_stack == NULL) {
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
"worker_stack_create() failed");
clean_child_exit(APEXIT_CHILDFATAL);
}
loops = prev_threads_created = 0;
while (1) {
for (i = 0; i < ap_threads_per_child; i++) {
int status = ap_scoreboard_image->servers[child_num_arg][i].status;
if (status != SERVER_GRACEFUL && status != SERVER_DEAD) {
continue;
}
my_info = (proc_info *)malloc(sizeof(proc_info));
if (my_info == NULL) {
ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf,
"malloc: out of memory");
clean_child_exit(APEXIT_CHILDFATAL);
}
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 = apr_thread_create(&threads[i], thread_attr,
worker_thread, my_info, pchild);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
"apr_thread_create: unable to create worker thread");
/* 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 if we exit. */
apr_sleep(10 * APR_USEC_PER_SEC);
clean_child_exit(APEXIT_CHILDFATAL);
}
threads_created++;
}
if (start_thread_may_exit || threads_created == ap_threads_per_child) {
break;
}
/* wait for previous generation to clean up an entry */
apr_sleep(1 * APR_USEC_PER_SEC);
++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, ap_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 **threads)
{
int i;
apr_status_t rv, thread_rv;
for (i = 0; i < ap_threads_per_child; i++) {
if (threads[i]) { /* if we ever created this thread */
rv = apr_thread_join(&thread_rv, threads[i]);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
"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,
"apr_thread_join: unable to join the start "
"thread");
}
}
static void child_main(int child_num_arg)
{
apr_thread_t **threads;
apr_status_t rv;
thread_starter *ts;
apr_threadattr_t *thread_attr;
apr_thread_t *start_thread_id;
ap_my_pid = getpid();
apr_pool_create(&pchild, pconf);
/*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(&accept_mutex, ap_lock_fname,
pchild));
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
"Couldn't initialize cross-process lock in child");
clean_child_exit(APEXIT_CHILDFATAL);
}
if (unixd_setup_child()) {
clean_child_exit(APEXIT_CHILDFATAL);
}
ap_run_child_init(pchild, ap_server_conf);
/* 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.
*/
rv = apr_setup_signal_thread();
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
"Couldn't initialize signal thread");
clean_child_exit(APEXIT_CHILDFATAL);
}
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 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
*/
threads = (apr_thread_t **)calloc(1,
sizeof(apr_thread_t *) * ap_threads_per_child);
if (threads == NULL) {
ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf,
"malloc: out of memory");
clean_child_exit(APEXIT_CHILDFATAL);
}
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);
ts->threads = threads;
ts->child_num_arg = child_num_arg;
ts->threadattr = thread_attr;
rv = apr_thread_create(&start_thread_id, thread_attr, start_threads,
ts, pchild);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
"apr_thread_create: unable to create worker thread");
/* 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 if we exit. */
apr_sleep(10 * APR_USEC_PER_SEC);
clean_child_exit(APEXIT_CHILDFATAL);
}
/* 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(threads);
}
else { /* !one_process */
/* remove SIGTERM from the set of blocked signals... if one of
* the other threads in the process needs to take us down
* (e.g., for MaxRequestsPerChild) it will send us SIGTERM
*/
unblock_signal(SIGTERM);
apr_signal(SIGTERM, dummy_signal_handler);
/* Watch for any messages from the parent over the POD */
while (1) {
rv = ap_mpm_pod_check(pod);
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;
}
}
if (rv == AP_GRACEFUL || rv == AP_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_GRACEFUL ? ST_GRACEFUL : ST_UNGRACEFUL);
break;
}
}
if (rv == AP_GRACEFUL) {
/* 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(threads);
}
}
free(threads);
clean_child_exit(resource_shortage ? APEXIT_CHILDSICK : 0);
}
static int make_child(server_rec *s, int slot)
{
int pid;
if (slot + 1 > ap_max_daemons_limit) {
ap_max_daemons_limit = slot + 1;
}
if (one_process) {
set_signals();
ap_scoreboard_image->parent[slot].pid = getpid();
child_main(slot);
}
if ((pid = fork()) == -1) {
ap_log_error(APLOG_MARK, APLOG_ERR, errno, s,
"fork: Unable to fork new process");
/* fork didn't succeed. Fix the scoreboard or else
* it will say SERVER_STARTING forever and ever
*/
ap_update_child_status_from_indexes(slot, 0, SERVER_DEAD, NULL);
/* 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(10 * APR_USEC_PER_SEC);
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.
*/
int status = bindprocessor(BINDPROCESS, (int)getpid(),
PROCESSOR_CLASS_ANY);
if (status != OK)
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, errno,
ap_server_conf,
"processor unbind failed %d", status);
#endif
RAISE_SIGSTOP(MAKE_CHILD);
apr_signal(SIGTERM, just_die);
child_main(slot);
clean_child_exit(0);
}
/* else */
ap_scoreboard_image->parent[slot].quiescing = 0;
ap_scoreboard_image->parent[slot].pid = 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) < 0) {
break;
}
--number_to_start;
}
}
/*
* 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;
worker_score *ws;
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;
/* 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 && totally_free_length == idle_spawn_rate)
break;
ps = &ap_scoreboard_image->parent[i];
for (j = 0; j < ap_threads_per_child; j++) {
ws = &ap_scoreboard_image->servers[i][j];
status = ws->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 (status <= SERVER_READY && status != SERVER_DEAD &&
!ps->quiescing &&
ps->generation == ap_my_generation &&
/* XXX the following shouldn't be necessary if we clean up
* properly after seg faults, but we're not yet GLA
*/
ps->pid != 0) {
++idle_thread_count;
}
}
if (any_dead_threads && totally_free_length < idle_spawn_rate
&& (!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;
}
/* XXX if (!ps->quiescing) is probably more reliable GLA */
if (!any_dying_threads) {
last_non_dead = i;
++total_non_dead;
}
}
ap_max_daemons_limit = last_non_dead + 1;
if (idle_thread_count > max_spare_threads) {
/* Kill off one child */
ap_mpm_pod_signal(pod, TRUE);
idle_spawn_rate = 1;
}
else if (idle_thread_count < min_spare_threads) {
/* terminate the free list */
if (free_length == 0) {
/* only report this condition once */
static int reported = 0;
if (!reported) {
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, 0,
ap_server_conf,
"server reached MaxClients setting, consider"
" raising the MaxClients setting");
reported = 1;
}
idle_spawn_rate = 1;
}
else {
if (free_length > idle_spawn_rate) {
free_length = idle_spawn_rate;
}
if (idle_spawn_rate >= 8) {
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, 0,
ap_server_conf,
"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]);
}
/* 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 (hold_off_on_exponential_spawning) {
--hold_off_on_exponential_spawning;
}
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;
apr_exit_why_e exitwhy;
int status, processed_status;
apr_proc_t pid;
int i;
while (!restart_pending && !shutdown_pending) {
ap_wait_or_timeout(&exitwhy, &status, &pid, pconf);
if (pid.pid != -1) {
processed_status = ap_process_child_status(&pid, exitwhy, status);
if (processed_status == APEXIT_CHILDFATAL) {
shutdown_pending = 1;
child_fatal = 1;
return;
}
/* non-fatal death... note that it's gone in the scoreboard. */
child_slot = find_child_by_pid(&pid);
if (child_slot >= 0) {
for (i = 0; i < ap_threads_per_child; i++)
ap_update_child_status_from_indexes(child_slot, i, SERVER_DEAD,
(request_rec *) NULL);
ap_scoreboard_image->parent[child_slot].pid = 0;
ap_scoreboard_image->parent[child_slot].quiescing = 0;
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
*/
make_child(ap_server_conf, child_slot);
--remaining_children_to_start;
}
#if APR_HAS_OTHER_CHILD
}
else if (apr_proc_other_child_read(&pid, 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.
*/
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0,
ap_server_conf,
"long lost child came home! (pid %ld)",
(long)pid.pid);
}
/* Don't perform idle maintenance when a child dies,
* only do it when there's a timeout. Remember only a
* finite number of children can die, and it's pretty
* pathological for a lot to die suddenly.
*/
continue;
}
else if (remaining_children_to_start) {
/* we hit a 1 second timeout in which none of the previous
* generation of children needed to be reaped... so assume
* they're all done, and pick up the slack if any is left.
*/
startup_children(remaining_children_to_start);
remaining_children_to_start = 0;
/* In any event we really shouldn't do the code below because
* few of the servers we just started are in the IDLE state
* yet, so we'd mistakenly create an extra server.
*/
continue;
}
perform_idle_server_maintenance();
}
}
int ap_mpm_run(apr_pool_t *_pconf, apr_pool_t *plog, server_rec *s)
{
int remaining_children_to_start;
apr_status_t rv;
ap_log_pid(pconf, ap_pid_fname);
first_server_limit = server_limit;
first_thread_limit = thread_limit;
if (changed_limit_at_restart) {
ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_NOERRNO, 0, s,
"WARNING: Attempt to change ServerLimit or ThreadLimit "
"ignored during restart");
changed_limit_at_restart = 0;
}
/* Initialize cross-process accept lock */
ap_lock_fname = apr_psprintf(_pconf, "%s.%" APR_PID_T_FMT,
ap_server_root_relative(_pconf, ap_lock_fname),
ap_my_pid);
rv = apr_proc_mutex_create(&accept_mutex, ap_lock_fname,
ap_accept_lock_mech, _pconf);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
"Couldn't create accept lock");
return 1;
}
#if APR_USE_SYSVSEM_SERIALIZE
if (ap_accept_lock_mech == APR_LOCK_DEFAULT ||
ap_accept_lock_mech == APR_LOCK_SYSVSEM) {
#else
if (ap_accept_lock_mech == APR_LOCK_SYSVSEM) {
#endif
rv = unixd_set_proc_mutex_perms(accept_mutex);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
"Couldn't set permissions on cross-process lock; "
"check User and Group directives");
return 1;
}
}
if (!is_graceful) {
if (ap_run_pre_mpm(s->process->pool, SB_SHARED) != OK) {
return 1;
}
/* fix the generation number in the global score; we just got a new,
* cleared scoreboard
*/
ap_scoreboard_image->global->running_generation = ap_my_generation;
}
set_signals();
/* Don't thrash... */
if (max_spare_threads < min_spare_threads + ap_threads_per_child)
max_spare_threads = min_spare_threads + ap_threads_per_child;
/* 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'll start a new one until
* we reach at least daemons_min_free. But we may be permitted to
* start more 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 (!is_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 */
hold_off_on_exponential_spawning = 10;
}
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
"%s configured -- resuming normal operations",
ap_get_server_version());
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, 0, ap_server_conf,
"Server built: %s", ap_get_server_built());
#ifdef AP_MPM_WANT_SET_ACCEPT_LOCK_MECH
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_DEBUG, 0, ap_server_conf,
"AcceptMutex: %s", ap_valid_accept_mutex_string);
#endif
restart_pending = shutdown_pending = 0;
server_main_loop(remaining_children_to_start);
if (shutdown_pending) {
/* Time to gracefully shut down:
* Kill child processes, tell them to call child_exit, etc...
* (By "gracefully" we don't mean graceful in the same sense as
* "apachectl graceful" where we allow old connections to finish.)
*/
ap_mpm_pod_killpg(pod, ap_daemons_limit, FALSE);
ap_reclaim_child_processes(1); /* Start with SIGTERM */
if (!child_fatal) {
/* cleanup pid file on normal shutdown */
const char *pidfile = NULL;
pidfile = ap_server_root_relative (pconf, ap_pid_fname);
if ( pidfile != NULL && unlink(pidfile) == 0)
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, 0,
ap_server_conf,
"removed PID file %s (pid=%ld)",
pidfile, (long)getpid());
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0,
ap_server_conf, "caught SIGTERM, shutting down");
}
return 1;
}
/* we've been told to restart */
apr_signal(SIGHUP, SIG_IGN);
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.
*/
++ap_my_generation;
ap_scoreboard_image->global->running_generation = ap_my_generation;
if (is_graceful) {
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
AP_SIG_GRACEFUL_STRING " received. Doing graceful restart");
/* wake up the children...time to die. But we'll have more soon */
ap_mpm_pod_killpg(pod, ap_daemons_limit, TRUE);
/* 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.
*/
ap_mpm_pod_killpg(pod, ap_daemons_limit, FALSE);
ap_reclaim_child_processes(1); /* Start with SIGTERM */
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
"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 worker_open_logs(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s)
{
apr_status_t rv;
pconf = p;
ap_server_conf = s;
if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) {
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ALERT|APLOG_STARTUP, 0,
NULL, "no listening sockets available, shutting down");
return DONE;
}
if (!one_process) {
if ((rv = ap_mpm_pod_open(pconf, &pod))) {
ap_log_error(APLOG_MARK, APLOG_CRIT|APLOG_STARTUP, rv, NULL,
"Could not open pipe-of-death.");
return DONE;
}
}
return OK;
}
static int worker_pre_config(apr_pool_t *pconf, apr_pool_t *plog,
apr_pool_t *ptemp)
{
static int restart_num = 0;
int no_detach, debug, foreground;
ap_directive_t *pdir;
ap_directive_t *max_clients = NULL;
apr_status_t rv;
/* make sure that "ThreadsPerChild" gets set before "MaxClients" */
for (pdir = ap_conftree; pdir != NULL; pdir = pdir->next) {
if (strncasecmp(pdir->directive, "ThreadsPerChild", 15) == 0) {
if (!max_clients) {
break; /* we're in the clear, got ThreadsPerChild first */
}
else {
/* now to swap the data */
ap_directive_t temp;
temp.directive = pdir->directive;
temp.args = pdir->args;
/* Make sure you don't change 'next', or you may get loops! */
/* XXX: first_child, parent, and data can never be set
* for these directives, right? -aaron */
temp.filename = pdir->filename;
temp.line_num = pdir->line_num;
pdir->directive = max_clients->directive;
pdir->args = max_clients->args;
pdir->filename = max_clients->filename;
pdir->line_num = max_clients->line_num;
max_clients->directive = temp.directive;
max_clients->args = temp.args;
max_clients->filename = temp.filename;
max_clients->line_num = temp.line_num;
break;
}
}
else if (!max_clients
&& strncasecmp(pdir->directive, "MaxClients", 10) == 0) {
max_clients = pdir;
}
}
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");
}
/* sigh, want this only the second time around */
if (restart_num++ == 1) {
is_graceful = 0;
if (!one_process && !foreground) {
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,
"apr_proc_detach failed");
return HTTP_INTERNAL_SERVER_ERROR;
}
}
parent_pid = ap_my_pid = getpid();
}
unixd_pre_config(ptemp);
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;
ap_daemons_limit = server_limit;
ap_threads_per_child = DEFAULT_THREADS_PER_CHILD;
ap_pid_fname = DEFAULT_PIDLOG;
ap_lock_fname = DEFAULT_LOCKFILE;
ap_max_requests_per_child = DEFAULT_MAX_REQUESTS_PER_CHILD;
ap_extended_status = 0;
apr_cpystrn(ap_coredump_dir, ap_server_root, sizeof(ap_coredump_dir));
return OK;
}
static void worker_hooks(apr_pool_t *p)
{
/* The worker open_logs phase 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_MIDDLE);
ap_hook_pre_config(worker_pre_config, 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);
if (min_spare_threads <= 0) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: detected MinSpareThreads set to non-positive.");
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"Resetting to 1 to avoid almost certain Apache failure.");
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"Please read the documentation.");
min_spare_threads = 1;
}
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_clients (cmd_parms *cmd, void *dummy,
const char *arg)
{
int max_clients;
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
/* It is ok to use ap_threads_per_child here because we are
* sure that it gets set before MaxClients in the pre_config stage. */
max_clients = atoi(arg);
if (max_clients < ap_threads_per_child) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: MaxClients (%d) must be at least as large",
max_clients);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" large as ThreadsPerChild (%d). Automatically",
ap_threads_per_child);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" increasing MaxClients to %d.",
ap_threads_per_child);
max_clients = ap_threads_per_child;
}
ap_daemons_limit = max_clients / ap_threads_per_child;
if ((max_clients > 0) && (max_clients % ap_threads_per_child)) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: MaxClients (%d) is not an integer multiple",
max_clients);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" of ThreadsPerChild (%d), lowering MaxClients to %d",
ap_threads_per_child,
ap_daemons_limit * ap_threads_per_child);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" for a maximum of %d child processes,",
ap_daemons_limit);
max_clients = ap_daemons_limit * ap_threads_per_child;
}
if (ap_daemons_limit > server_limit) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: MaxClients of %d would require %d servers,",
max_clients, ap_daemons_limit);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" and would exceed the ServerLimit value of %d.",
server_limit);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" Automatically lowering MaxClients to %d. To increase,",
server_limit);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" please see the ServerLimit directive.");
ap_daemons_limit = server_limit;
}
else if (ap_daemons_limit < 1) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: Require MaxClients > 0, setting to 1");
ap_daemons_limit = 1;
}
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;
}
ap_threads_per_child = atoi(arg);
if (ap_threads_per_child > thread_limit) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: ThreadsPerChild of %d exceeds ThreadLimit "
"value of %d", ap_threads_per_child,
thread_limit);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"threads, lowering ThreadsPerChild to %d. To increase, please"
" see the", thread_limit);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" ThreadLimit directive.");
ap_threads_per_child = thread_limit;
}
else if (ap_threads_per_child < 1) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: Require ThreadsPerChild > 0, setting to 1");
ap_threads_per_child = 1;
}
return NULL;
}
static const char *set_server_limit (cmd_parms *cmd, void *dummy, const char *arg)
{
int tmp_server_limit;
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
tmp_server_limit = atoi(arg);
/* you cannot change ServerLimit across a restart; ignore
* any such attempts
*/
if (first_server_limit &&
tmp_server_limit != server_limit) {
/* how do we log a message? the error log is a bit bucket at this
* point; we'll just have to set a flag so that ap_mpm_run()
* logs a warning later
*/
changed_limit_at_restart = 1;
return NULL;
}
server_limit = tmp_server_limit;
if (server_limit > MAX_SERVER_LIMIT) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: ServerLimit of %d exceeds compile time limit "
"of %d servers,", server_limit, MAX_SERVER_LIMIT);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" lowering ServerLimit to %d.", MAX_SERVER_LIMIT);
server_limit = MAX_SERVER_LIMIT;
}
else if (server_limit < 1) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: Require ServerLimit > 0, setting to 1");
server_limit = 1;
}
return NULL;
}
static const char *set_thread_limit (cmd_parms *cmd, void *dummy, const char *arg)
{
int tmp_thread_limit;
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
tmp_thread_limit = atoi(arg);
/* you cannot change ThreadLimit across a restart; ignore
* any such attempts
*/
if (first_thread_limit &&
tmp_thread_limit != thread_limit) {
/* how do we log a message? the error log is a bit bucket at this
* point; we'll just have to set a flag so that ap_mpm_run()
* logs a warning later
*/
changed_limit_at_restart = 1;
return NULL;
}
thread_limit = tmp_thread_limit;
if (thread_limit > MAX_THREAD_LIMIT) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: ThreadLimit of %d exceeds compile time limit "
"of %d servers,", thread_limit, MAX_THREAD_LIMIT);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" lowering ThreadLimit to %d.", MAX_THREAD_LIMIT);
thread_limit = MAX_THREAD_LIMIT;
}
else if (thread_limit < 1) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: Require ThreadLimit > 0, setting to 1");
thread_limit = 1;
}
return NULL;
}
static const command_rec worker_cmds[] = {
UNIX_DAEMON_COMMANDS,
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 children, to handle request spikes"),
AP_INIT_TAKE1("MaxSpareThreads", set_max_spare_threads, NULL, RSRC_CONF,
"Maximum number of idle children"),
AP_INIT_TAKE1("MaxClients", set_max_clients, NULL, RSRC_CONF,
"Maximum number of children alive at the same time"),
AP_INIT_TAKE1("ThreadsPerChild", set_threads_per_child, NULL, RSRC_CONF,
"Number of threads each child creates"),
AP_INIT_TAKE1("ServerLimit", set_server_limit, NULL, RSRC_CONF,
"Maximum value of MaxClients for this run of Apache"),
AP_INIT_TAKE1("ThreadLimit", set_thread_limit, NULL, RSRC_CONF,
"Maximum worker threads in a server for this run of Apache"),
{ NULL }
};
module AP_MODULE_DECLARE_DATA mpm_worker_module = {
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 */
};
1.1 httpd-2.0/server/mpm/experimental/leader/mpm.h
Index: mpm.h
===================================================================
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2000-2002 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
* Portions of this software are based upon public domain software
* originally written at the National Center for Supercomputing Applications,
* University of Illinois, Urbana-Champaign.
*/
#include "scoreboard.h"
#include "unixd.h"
#ifndef APACHE_MPM_LEADER_H
#define APACHE_MPM_LEADER_H
#define LEADER_MPM
#define MPM_NAME "Leader-Follower"
#define AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
#define AP_MPM_WANT_WAIT_OR_TIMEOUT
#define AP_MPM_WANT_PROCESS_CHILD_STATUS
#define AP_MPM_WANT_SET_PIDFILE
#define AP_MPM_WANT_SET_SCOREBOARD
#define AP_MPM_WANT_SET_LOCKFILE
#define AP_MPM_WANT_SET_MAX_REQUESTS
#define AP_MPM_WANT_SET_COREDUMPDIR
#define AP_MPM_WANT_SET_ACCEPT_LOCK_MECH
#define AP_MPM_DISABLE_NAGLE_ACCEPTED_SOCK
#define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid)
#define MPM_NOTE_CHILD_KILLED(i) (MPM_CHILD_PID(i) = 0)
#define MPM_ACCEPT_FUNC unixd_accept
extern int ap_threads_per_child;
extern int ap_max_daemons_limit;
extern server_rec *ap_server_conf;
extern char ap_coredump_dir[MAX_STRING_LEN];
#endif /* APACHE_MPM_LEADER_H */