mpmt_pthread.c revision 1ccd992d37d62c8cb2056126f2234f64ec189bfd
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2000 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.
*/
#define CORE_PRIVATE
#include "apr_portable.h"
#include "apr_strings.h"
#include "apr_file_io.h"
#include "apr_thread_proc.h"
#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 "unixd.h"
#include "mpm_common.h"
#include "ap_iol.h"
#include "ap_listen.h"
#include "scoreboard.h"
#ifdef HAVE_NETINET_TCP_H
#include <netinet/tcp.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#include <pthread.h>
#include <signal.h>
/*
* Actual definitions of config globals
*/
int ap_threads_per_child=0; /* Worker threads per child */
int ap_max_requests_per_child=0;
static const char *ap_pid_fname=NULL;
API_VAR_EXPORT const char *ap_scoreboard_fname=NULL;
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 time_t ap_restart_time=0;
API_VAR_EXPORT int ap_extended_status = 0;
static int workers_may_exit = 0;
static int requests_this_child;
static int num_listensocks = 0;
static apr_socket_t **listensocks;
/* The structure used to pass unique initialization info to each thread */
typedef struct {
int pid;
int tid;
int sd;
apr_pool_t *tpool; /* "pthread" would be confusing */
} proc_info;
/*
* The max child slot ever assigned, preserved across restarts. Necessary
* to deal with MaxClients changes across SIGWINCH restarts. We use this
* value to optimize routines that have to scan the entire scoreboard.
*/
int ap_max_daemons_limit = -1;
char ap_coredump_dir[MAX_STRING_LEN];
static apr_file_t *pipe_of_death_in = NULL;
static apr_file_t *pipe_of_death_out = NULL;
static pthread_mutex_t pipe_of_death_mutex;
/* *Non*-shared http_main globals... */
server_rec *ap_server_conf;
/* one_process --- debugging mode variable; can be set from the command line
* with the -X flag. If set, this gets you the child_main loop running
* in the process which originally started up (no detach, no make_child),
* which is 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 */
unsigned int ap_my_pid; /* Linux getpid() doesn't work except in main
thread. Use this instead */
/* Keep track of the number of worker threads currently active */
static int worker_thread_count;
static pthread_mutex_t worker_thread_count_mutex;
/* Locks for accept serialization */
static pthread_mutex_t thread_accept_mutex = PTHREAD_MUTEX_INITIALIZER;
static apr_lock_t *process_accept_mutex;
static const char *lock_fname;
#ifdef NO_SERIALIZED_ACCEPT
#define SAFE_ACCEPT(stmt) APR_SUCCESS
#else
#define SAFE_ACCEPT(stmt) (stmt)
#endif
API_EXPORT(int) ap_get_max_daemons(void)
{
return ap_max_daemons_limit;
}
/* a clean exit from a child with proper cleanup */
static void clean_child_exit(int code) __attribute__ ((noreturn));
void clean_child_exit(int code)
{
if (pchild) {
apr_destroy_pool(pchild);
}
exit(code);
}
/* handle all varieties of core dumping signals */
static void sig_coredump(int sig)
{
chdir(ap_coredump_dir);
apr_signal(sig, SIG_DFL);
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;
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.
*/
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;
if (is_graceful) {
apr_kill_cleanup(pconf, NULL, ap_cleanup_shared_mem);
}
}
static void sig_term(int sig)
{
ap_start_shutdown();
}
static void restart(int sig)
{
#ifndef WIN32
ap_start_restart(sig == SIGWINCH);
#else
ap_start_restart(1);
#endif
}
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 WINCH while we're busy processing one */
sigaddset(&sa.sa_mask, SIGHUP);
sigaddset(&sa.sa_mask, SIGWINCH);
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(SIGWINCH, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGWINCH)");
#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 SIGWINCH
apr_signal(SIGWINCH, restart);
#endif /* SIGWINCH */
#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 - Does this really work? - Manoj */
return is_graceful;
}
/*****************************************************************
* Child process main loop.
*/
static void process_socket(apr_pool_t *p, apr_socket_t *sock, int my_child_num, int my_thread_num)
{
BUFF *conn_io;
conn_rec *current_conn;
ap_iol *iol;
long conn_id = my_child_num * HARD_THREAD_LIMIT + my_thread_num;
int csd;
(void) apr_get_os_sock(&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_close_socket(sock);
return;
}
ap_sock_disable_nagle(csd);
iol = ap_iol_attach_socket(p, sock);
(void) ap_update_child_status(my_child_num, my_thread_num,
SERVER_BUSY_READ, (request_rec *) NULL);
conn_io = ap_bcreate(p, B_RDWR);
ap_bpush_iol(conn_io, iol);
current_conn = ap_new_apr_connection(p, ap_server_conf, conn_io, sock,
conn_id);
ap_process_connection(current_conn);
ap_lingering_close(current_conn);
}
/* Sets workers_may_exit if we received a character on the pipe_of_death */
static void check_pipe_of_death(void)
{
pthread_mutex_lock(&pipe_of_death_mutex);
if (!workers_may_exit) {
apr_status_t ret;
char pipe_read_char;
apr_ssize_t n = 1;
ret = apr_recv(listensocks[0], &pipe_read_char, &n);
if (apr_canonical_error(ret) == APR_EAGAIN) {
/* It lost the lottery. It must continue to suffer
* through a life of servitude. */
}
else {
/* It won the lottery (or something else is very
* wrong). Embrace death with open arms. */
workers_may_exit = 1;
}
}
pthread_mutex_unlock(&pipe_of_death_mutex);
}
static void * worker_thread(void * dummy)
{
proc_info * ti = dummy;
int process_slot = ti->pid;
int thread_slot = ti->tid;
apr_pool_t *tpool = ti->tpool;
apr_socket_t *csd = NULL;
apr_pool_t *ptrans; /* Pool for per-transaction stuff */
apr_socket_t *sd = NULL;
int n;
int curr_pollfd, last_pollfd = 0;
apr_pollfd_t *pollset;
apr_status_t rv;
free(ti);
apr_create_pool(&ptrans, tpool);
pthread_mutex_lock(&worker_thread_count_mutex);
worker_thread_count++;
pthread_mutex_unlock(&worker_thread_count_mutex);
apr_setup_poll(&pollset, num_listensocks+1, tpool);
for(n=0 ; n <= num_listensocks ; ++n)
apr_add_poll_socket(pollset, listensocks[n], APR_POLLIN);
/* TODO: Switch to a system where threads reuse the results from earlier
poll calls - manoj */
while (!workers_may_exit) {
workers_may_exit |= (ap_max_requests_per_child != 0) && (requests_this_child <= 0);
if (workers_may_exit) break;
(void) ap_update_child_status(process_slot, thread_slot, SERVER_READY,
(request_rec *) NULL);
pthread_mutex_lock(&thread_accept_mutex);
if (workers_may_exit) {
pthread_mutex_unlock(&thread_accept_mutex);
break;
}
if ((rv = SAFE_ACCEPT(apr_lock(process_accept_mutex)))
!= APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
"apr_lock failed. Attempting to shutdown "
"process gracefully.");
workers_may_exit = 1;
}
while (!workers_may_exit) {
apr_status_t ret;
apr_int16_t event;
ret = apr_poll(pollset, &n, -1);
if (ret != APR_SUCCESS) {
if (apr_canonical_error(ret) == APR_EINTR) {
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)");
workers_may_exit = 1;
}
if (workers_may_exit) break;
apr_get_revents(&event, listensocks[0], pollset);
if (event & APR_POLLIN) {
/* A process got a signal on the shutdown pipe. Check if we're
* the lucky process to die. */
check_pipe_of_death();
continue;
}
if (num_listensocks == 1) {
sd = ap_listeners->sd;
goto got_fd;
}
else {
/* find a listener */
curr_pollfd = last_pollfd;
do {
curr_pollfd++;
if (curr_pollfd > num_listensocks) {
curr_pollfd = 1;
}
/* XXX: Should we check for POLLERR? */
apr_get_revents(&event, listensocks[curr_pollfd], pollset);
if (event & APR_POLLIN) {
last_pollfd = curr_pollfd;
sd=listensocks[curr_pollfd];
goto got_fd;
}
} while (curr_pollfd != last_pollfd);
}
}
got_fd:
if (!workers_may_exit) {
if ((rv = apr_accept(&csd, sd, ptrans)) != APR_SUCCESS) {
csd = NULL;
ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf,
"apr_accept");
}
if ((rv = SAFE_ACCEPT(apr_unlock(process_accept_mutex)))
!= APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
"apr_unlock failed. Attempting to shutdown "
"process gracefully.");
workers_may_exit = 1;
}
pthread_mutex_unlock(&thread_accept_mutex);
if (csd != NULL) {
process_socket(ptrans, csd, process_slot, thread_slot);
requests_this_child--;
}
}
else {
if ((rv = SAFE_ACCEPT(apr_unlock(process_accept_mutex)))
!= APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
"apr_unlock failed. Attempting to shutdown "
"process gracefully.");
workers_may_exit = 1;
}
pthread_mutex_unlock(&thread_accept_mutex);
break;
}
apr_clear_pool(ptrans);
}
apr_destroy_pool(tpool);
ap_update_child_status(process_slot, thread_slot, SERVER_DEAD,
(request_rec *) NULL);
pthread_mutex_lock(&worker_thread_count_mutex);
worker_thread_count--;
if (worker_thread_count == 0) {
/* All the threads have exited, now finish the shutdown process
* by signalling the sigwait thread */
kill(ap_my_pid, SIGTERM);
}
pthread_mutex_unlock(&worker_thread_count_mutex);
return NULL;
}
static void child_main(int child_num_arg)
{
sigset_t sig_mask;
int signal_received;
pthread_t thread;
pthread_attr_t thread_attr;
int i;
int my_child_num = child_num_arg;
proc_info *my_info = NULL;
ap_listen_rec *lr;
apr_status_t rv;
ap_my_pid = getpid();
apr_create_pool(&pchild, pconf);
/*stuff to do before we switch id's, so we have permissions.*/
reopen_scoreboard(pchild);
rv = SAFE_ACCEPT(apr_child_init_lock(&process_accept_mutex, 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_child_init_hook(pchild, ap_server_conf);
/*done with init critical section */
/* All threads should mask signals out, accoring to sigwait(2) man page */
sigfillset(&sig_mask);
#ifdef SIGPROCMASK_SETS_THREAD_MASK
if (sigprocmask(SIG_SETMASK, &sig_mask, NULL) != 0) {
ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf, "sigprocmask");
}
#else
if ((rv = pthread_sigmask(SIG_SETMASK, &sig_mask, NULL)) != 0) {
#ifdef PTHREAD_SETS_ERRNO
rv = errno;
#endif
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, "pthread_sigmask");
}
#endif
requests_this_child = ap_max_requests_per_child;
/* Set up the pollfd array */
listensocks = apr_pcalloc(pchild,
sizeof(*listensocks) * (num_listensocks + 1));
#if APR_FILES_AS_SOCKETS
apr_socket_from_file(&listensocks[0], pipe_of_death_in);
#endif
for (lr = ap_listeners, i = 1; i <= num_listensocks; lr = lr->next, ++i)
listensocks[i]=lr->sd;
/* Setup worker threads */
worker_thread_count = 0;
pthread_mutex_init(&worker_thread_count_mutex, NULL);
pthread_mutex_init(&pipe_of_death_mutex, NULL);
pthread_attr_init(&thread_attr);
#ifdef PTHREAD_ATTR_SETDETACHSTATE_ARG2_ADDR
{
int on = 1;
pthread_attr_setdetachstate(&thread_attr, &on);
}
#else
pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
#endif
for (i=0; i < ap_threads_per_child; i++) {
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;
apr_create_pool(&my_info->tpool, pchild);
/* We are creating threads right now */
(void) ap_update_child_status(my_child_num, i, SERVER_STARTING,
(request_rec *) NULL);
#ifndef NO_THREADS
if ((rv = pthread_create(&thread, &thread_attr, worker_thread, my_info))) {
#ifdef PTHREAD_SETS_ERRNO
rv = errno;
#endif
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
"pthread_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. */
sleep(10);
clean_child_exit(APEXIT_CHILDFATAL);
}
#else
worker_thread(my_info);
/* The SIGTERM shouldn't let us reach this point, but just in case... */
clean_child_exit(APEXIT_OK);
#endif
/* We let each thread update it's own scoreboard entry. This is done
* because it let's us deal with tid better.
*/
}
pthread_attr_destroy(&thread_attr);
/* This thread will be the one responsible for handling signals */
sigemptyset(&sig_mask);
sigaddset(&sig_mask, SIGTERM);
sigaddset(&sig_mask, SIGINT);
ap_sigwait(&sig_mask, &signal_received);
switch (signal_received) {
case SIGTERM:
case SIGINT:
just_die(signal_received);
break;
default:
ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf,
"received impossible signal: %d", signal_received);
just_die(SIGTERM);
}
}
static int make_child(server_rec *s, int slot, time_t now)
{
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);
}
/* Tag this slot as occupied so that perform_idle_server_maintenance
* doesn't try to steal it */
(void) ap_update_child_status(slot, 0, SERVER_STARTING, (request_rec *) NULL);
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
*/
(void) ap_update_child_status(slot, 0, SERVER_DEAD, (request_rec *) 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. */
sleep(10);
return -1;
}
if (!pid) {
#ifdef AIX_BIND_PROCESSOR
/* By default, AIX binds to a single processor. This bit unbinds
children which will then bind to another CPU.
*/
#include <sys/processor.h>
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);
return 0;
}
/* else */
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) < 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;
thread_score *ss;
time_t now = 0;
int free_length;
int free_slots[MAX_SPAWN_RATE];
int last_non_dead;
int total_non_dead;
apr_ssize_t one = 1;
apr_status_t rv;
/* initialize the free_list */
free_length = 0;
idle_thread_count = 0;
last_non_dead = -1;
total_non_dead = 0;
ap_sync_scoreboard_image();
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 all_dead_threads = 1;
int idle_thread_addition = 0;
if (i >= ap_max_daemons_limit && free_length == idle_spawn_rate)
break;
for (j = 0; j < ap_threads_per_child; j++) {
ss = &ap_scoreboard_image->servers[i][j];
status = ss->status;
any_dying_threads = any_dying_threads || (status == SERVER_DEAD)
|| (status == SERVER_GRACEFUL);
all_dead_threads = all_dead_threads && (status == SERVER_DEAD);
/* 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) {
++idle_thread_addition;
}
}
if (all_dead_threads && free_length < idle_spawn_rate) {
free_slots[free_length] = i;
++free_length;
}
if (!all_dead_threads) {
last_non_dead = i;
}
if (!any_dying_threads) {
++total_non_dead;
idle_thread_count += idle_thread_addition;
}
}
ap_max_daemons_limit = last_non_dead + 1;
if (idle_thread_count > max_spare_threads) {
/* Kill off one child */
char char_of_death = '!';
if ((rv = apr_write(pipe_of_death_out, &char_of_death, &one)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf, "write pipe_of_death");
}
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 (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", idle_spawn_rate,
idle_thread_count, total_non_dead);
}
for (i = 0; i < free_length; ++i) {
make_child(ap_server_conf, free_slots[i], now);
}
/* 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;
ap_wait_t status;
apr_proc_t pid;
int i;
while (!restart_pending && !shutdown_pending) {
ap_wait_or_timeout(&status, &pid, pconf);
if (pid.pid != -1) {
ap_process_child_status(&pid, status);
/* non-fatal death... note that it's gone in the scoreboard. */
child_slot = find_child_by_pid(&pid);
if (child_slot >= 0) {
ap_mpmt_pthread_force_reset_connection_status(child_slot);
for (i = 0; i < ap_threads_per_child; i++)
ap_update_child_status(child_slot, i, SERVER_DEAD, (request_rec *) NULL);
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, time(NULL));
--remaining_children_to_start;
}
#if APR_HAS_OTHER_CHILD
}
else if (apr_reap_other_child(&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;
apr_ssize_t one = 1;
pconf = _pconf;
ap_server_conf = s;
rv = apr_create_pipe(&pipe_of_death_in, &pipe_of_death_out, pconf);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv,
(const server_rec*) ap_server_conf,
"apr_create_pipe (pipe_of_death)");
exit(1);
}
if ((rv = apr_set_pipe_timeout(pipe_of_death_in, 0)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv,
(const server_rec*) ap_server_conf,
"apr_set_pipe_timeout (pipe_of_death)");
exit(1);
}
ap_server_conf = s;
if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) {
/* XXX: hey, what's the right way for the mpm to indicate a fatal error? */
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ALERT, 0, s,
"no listening sockets available, shutting down");
return 1;
}
ap_log_pid(pconf, ap_pid_fname);
/* Initialize cross-process accept lock */
lock_fname = apr_psprintf(_pconf, "%s.%u",
ap_server_root_relative(_pconf, lock_fname),
ap_my_pid);
rv = apr_create_lock(&process_accept_mutex, APR_MUTEX, APR_CROSS_PROCESS,
lock_fname, _pconf);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
"Couldn't create cross-process lock");
return 1;
}
if (!is_graceful) {
reinit_scoreboard(pconf);
}
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 SIGWINCH). 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());
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...
*/
if (unixd_killpg(getpgrp(), SIGTERM) < 0) {
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "killpg SIGTERM");
}
ap_reclaim_child_processes(1); /* Start with SIGTERM */
/* 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;
update_scoreboard_global();
if (is_graceful) {
int i, j;
char char_of_death = '!';
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
"SIGWINCH received. Doing graceful restart");
/* give the children the signal to die */
for (i = 0; i < ap_daemons_limit;) {
if ((rv = apr_write(pipe_of_death_in, &char_of_death, &one)) != APR_SUCCESS) {
if (apr_canonical_error(rv) == APR_EINTR) continue;
ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf, "write pipe_of_death");
}
i++;
}
/* This is mostly for debugging... so that we know what is still
* gracefully dealing with existing request.
*/
for (i = 0; i < ap_daemons_limit; ++i) {
for (j = 0; j < ap_threads_per_child; j++) {
if (ap_scoreboard_image->servers[i][j].status != SERVER_DEAD) {
ap_scoreboard_image->servers[i][j].status = SERVER_GRACEFUL;
}
}
}
}
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.
*/
if (unixd_killpg(getpgrp(), SIGTERM) < 0) {
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "killpg SIGTERM");
}
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");
}
if (!is_graceful) {
ap_restart_time = time(NULL);
}
return 0;
}
static void mpmt_pthread_pre_config(apr_pool_t *pconf, apr_pool_t *plog, apr_pool_t *ptemp)
{
static int restart_num = 0;
int no_detach = 0;
one_process = !!getenv("ONE_PROCESS");
no_detach = !!getenv("NO_DETACH");
/* sigh, want this only the second time around */
if (restart_num++ == 1) {
is_graceful = 0;
if (!one_process && !no_detach) {
apr_detach();
}
ap_my_pid = getpid();
}
unixd_pre_config();
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 = HARD_SERVER_LIMIT;
ap_threads_per_child = DEFAULT_THREADS_PER_CHILD;
ap_pid_fname = DEFAULT_PIDLOG;
ap_scoreboard_fname = DEFAULT_SCOREBOARD;
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));
}
static void mpmt_pthread_hooks(void)
{
INIT_SIGLIST()
one_process = 0;
ap_hook_pre_config(mpmt_pthread_pre_config, NULL, NULL, AP_HOOK_MIDDLE);
}
static const char *set_pidfile(cmd_parms *cmd, void *dummy, const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
if (cmd->server->is_virtual) {
return "PidFile directive not allowed in <VirtualHost>";
}
ap_pid_fname = arg;
return NULL;
}
static const char *set_scoreboard(cmd_parms *cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
ap_scoreboard_fname = arg;
return NULL;
}
static const char *set_lockfile(cmd_parms *cmd, void *dummy, const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
lock_fname = arg;
return NULL;
}
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_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;
}
ap_daemons_limit = atoi(arg);
if (ap_daemons_limit > HARD_SERVER_LIMIT) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: MaxClients of %d exceeds compile time limit "
"of %d servers,", ap_daemons_limit, HARD_SERVER_LIMIT);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" lowering MaxClients to %d. To increase, please "
"see the", HARD_SERVER_LIMIT);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" HARD_SERVER_LIMIT define in %s.",
AP_MPM_HARD_LIMITS_FILE);
ap_daemons_limit = HARD_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 > HARD_THREAD_LIMIT) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
"WARNING: ThreadsPerChild of %d exceeds compile time"
"limit of %d threads,", ap_threads_per_child,
HARD_THREAD_LIMIT);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" lowering ThreadsPerChild to %d. To increase, please"
" see the", HARD_THREAD_LIMIT);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" HARD_THREAD_LIMIT define in %s.",
AP_MPM_HARD_LIMITS_FILE);
}
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_max_requests(cmd_parms *cmd, void *dummy,
const char *arg)
{
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
ap_max_requests_per_child = atoi(arg);
return NULL;
}
static const char *set_coredumpdir (cmd_parms *cmd, void *dummy,
const char *arg)
{
apr_finfo_t finfo;
const char *fname;
const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
if (err != NULL) {
return err;
}
fname = ap_server_root_relative(cmd->pool, arg);
if ((apr_stat(&finfo, fname, cmd->pool) != APR_SUCCESS) ||
(finfo.filetype != APR_DIR)) {
return apr_pstrcat(cmd->pool, "CoreDumpDirectory ", fname,
" does not exist or is not a directory", NULL);
}
apr_cpystrn(ap_coredump_dir, fname, sizeof(ap_coredump_dir));
return NULL;
}
static const command_rec mpmt_pthread_cmds[] = {
UNIX_DAEMON_COMMANDS
LISTEN_COMMANDS
AP_INIT_TAKE1("PidFile", set_pidfile, NULL, RSRC_CONF,
"A file for logging the server process ID"),
AP_INIT_TAKE1("ScoreBoardFile", set_scoreboard, NULL, RSRC_CONF,
"A file for Apache to maintain runtime process management information"),
AP_INIT_TAKE1("LockFile", set_lockfile, NULL, RSRC_CONF,
"The lockfile used when Apache needs to lock the accept() call"),
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_server_limit, 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("MaxRequestsPerChild", set_max_requests, NULL, RSRC_CONF,
"Maximum number of requests a particular child serves before dying."),
AP_INIT_TAKE1("CoreDumpDirectory", set_coredumpdir, NULL, RSRC_CONF,
"The location of the directory Apache changes to before dumping core"),
{ NULL }
};
module MODULE_VAR_EXPORT mpm_mpmt_pthread_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 */
mpmt_pthread_cmds, /* command apr_table_t */
NULL, /* handlers */
mpmt_pthread_hooks /* register_hooks */
};