mpmt_os2.c

Apache 2.0.63 is the current stable version of the 2.0 series, and is recommended over any previous

/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* Multi-process, multi-threaded MPM for OS/2
 *
 * Server consists of
 * - a main, parent process
 * - a small, static number of child processes
 *
 * The parent process's job is to manage the child processes. This involves
 * spawning children as required to ensure there are always ap_daemons_to_start
 * processes accepting connections.
 *
 * Each child process consists of a a pool of worker threads and a
 * main thread that accepts connections & passes them to the workers via
 * a work queue. The worker thread pool is dynamic, managed by a maintanence
 * thread so that the number of idle threads is kept between
 * min_spare_threads & max_spare_threads.
 *
 */

/*
 Todo list
 - Enforce MaxClients somehow
*/
#define CORE_PRIVATE
#define INCL_NOPMAPI
#define INCL_DOS
#define INCL_DOSERRORS

#include "ap_config.h"
#include "httpd.h"
#include "mpm_default.h"
#include "http_main.h"
#include "http_log.h"
#include "http_config.h"
#include "http_core.h"		/* for get_remote_host */
#include "http_connection.h"
#include "mpm.h"
#include "ap_mpm.h"
#include "ap_listen.h"
#include "apr_portable.h"
#include "mpm_common.h"
#include "apr_strings.h"
#include <os2.h>
#include <process.h>

/* We don't need many processes, 
 * they're only for redundancy in the event of a crash 
 */
#define HARD_SERVER_LIMIT 10

/* Limit on the total number of threads per process
 */
#ifndef HARD_THREAD_LIMIT
#define HARD_THREAD_LIMIT 256
#endif

server_rec *ap_server_conf;
static apr_pool_t *pconf = NULL;		/* Pool for config stuff */
static const char *ap_pid_fname=NULL;

/* Config globals */
static int one_process = 0;
static int ap_daemons_to_start = 0;
static int ap_thread_limit = 0;
static int ap_max_requests_per_child = 0;
int ap_min_spare_threads = 0;
int ap_max_spare_threads = 0;

/* Keep track of a few interesting statistics */
int ap_max_daemons_limit = -1;

/* volatile just in case */
static int volatile shutdown_pending;
static int volatile restart_pending;
static int volatile is_graceful = 0;
ap_generation_t volatile ap_my_generation=0; /* Used by the scoreboard */
static int is_parent_process=TRUE;
HMTX ap_mpm_accept_mutex = 0;

/* An array of these is stored in a shared memory area for passing
 * sockets from the parent to child processes
 */
typedef struct {
    struct sockaddr_in name;
    apr_os_sock_t listen_fd;
} listen_socket_t;

typedef struct {
    HMTX accept_mutex;
    listen_socket_t listeners[1];
} parent_info_t;

static char master_main();
static void spawn_child(int slot);
void ap_mpm_child_main(apr_pool_t *pconf);
static void set_signals();


int ap_mpm_run(apr_pool_t *_pconf, apr_pool_t *plog, server_rec *s )
{
    char *listener_shm_name;
    parent_info_t *parent_info;
    ULONG rc;
    pconf = _pconf;
    ap_server_conf = s;
    restart_pending = 0;

    DosSetMaxFH(ap_thread_limit * 2);
    listener_shm_name = apr_psprintf(pconf, "/sharemem/httpd/parent_info.%d", getppid());
    rc = DosGetNamedSharedMem((PPVOID)&parent_info, listener_shm_name, PAG_READ);
    is_parent_process = rc != 0;
    ap_scoreboard_fname = apr_psprintf(pconf, "/sharemem/httpd/scoreboard.%d", is_parent_process ? getpid() : getppid());

    if (rc == 0) {
        /* Child process */
        ap_listen_rec *lr;
        int num_listeners = 0;

        ap_mpm_accept_mutex = parent_info->accept_mutex;

        /* Set up a default listener if necessary */
        if (ap_listeners == NULL) {
            ap_listen_rec *lr = apr_pcalloc(s->process->pool, sizeof(ap_listen_rec));
            ap_listeners = lr;
            apr_sockaddr_info_get(&lr->bind_addr, "0.0.0.0", APR_UNSPEC,
                                  DEFAULT_HTTP_PORT, 0, s->process->pool);
            apr_socket_create(&lr->sd, lr->bind_addr->family,
                              SOCK_STREAM, s->process->pool);
        }

        for (lr = ap_listeners; lr; lr = lr->next) {
            apr_sockaddr_t *sa;
            apr_os_sock_put(&lr->sd, &parent_info->listeners[num_listeners].listen_fd, pconf);
            apr_socket_addr_get(&sa, APR_LOCAL, lr->sd);
            num_listeners++;
        }

        DosFreeMem(parent_info);

        /* Do the work */
        ap_mpm_child_main(pconf);

        /* Outta here */
        return 1;
    }
    else {
        /* Parent process */
        char restart;
        is_parent_process = TRUE;

        if (ap_setup_listeners(ap_server_conf) < 1) {
            ap_log_error(APLOG_MARK, APLOG_ALERT, 0, s,
                         "no listening sockets available, shutting down");
            return 1;
        }

        ap_log_pid(pconf, ap_pid_fname);

        restart = master_main();
        ++ap_my_generation;
        ap_scoreboard_image->global->running_generation = ap_my_generation;

        if (!restart) {
            const char *pidfile = ap_server_root_relative(pconf, ap_pid_fname);

            if (pidfile != NULL && remove(pidfile) == 0) {
                ap_log_error(APLOG_MARK, APLOG_INFO, APR_SUCCESS,
                             ap_server_conf, "removed PID file %s (pid=%d)",
                             pidfile, getpid());
            }

            ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
                         "caught SIGTERM, shutting down");
            return 1;
        }
    }  /* Parent process */

    return 0; /* Restart */
}



/* Main processing of the parent process
 * returns TRUE if restarting
 */
static char master_main()
{
    server_rec *s = ap_server_conf;
    ap_listen_rec *lr;
    parent_info_t *parent_info;
    char *listener_shm_name;
    int listener_num, num_listeners, slot;
    ULONG rc;

    printf("%s \n", ap_get_server_version());
    set_signals();

    if (ap_setup_listeners(ap_server_conf) < 1) {
        ap_log_error(APLOG_MARK, APLOG_ALERT, 0, s,
                     "no listening sockets available, shutting down");
        return FALSE;
    }

    /* Allocate a shared memory block for the array of listeners */
    for (num_listeners = 0, lr = ap_listeners; lr; lr = lr->next) {
        num_listeners++;
    }

    listener_shm_name = apr_psprintf(pconf, "/sharemem/httpd/parent_info.%d", getpid());
    rc = DosAllocSharedMem((PPVOID)&parent_info, listener_shm_name,
                           sizeof(parent_info_t) + num_listeners * sizeof(listen_socket_t),
                           PAG_READ|PAG_WRITE|PAG_COMMIT);

    if (rc) {
        ap_log_error(APLOG_MARK, APLOG_ALERT, APR_FROM_OS_ERROR(rc), s,
                     "failure allocating shared memory, shutting down");
        return FALSE;
    }

    /* Store the listener sockets in the shared memory area for our children to see */
    for (listener_num = 0, lr = ap_listeners; lr; lr = lr->next, listener_num++) {
        apr_os_sock_get(&parent_info->listeners[listener_num].listen_fd, lr->sd);
    }

    /* Create mutex to prevent multiple child processes from detecting
     * a connection with apr_poll()
     */

    rc = DosCreateMutexSem(NULL, &ap_mpm_accept_mutex, DC_SEM_SHARED, FALSE);

    if (rc) {
        ap_log_error(APLOG_MARK, APLOG_ALERT, APR_FROM_OS_ERROR(rc), s,
                     "failure creating accept mutex, shutting down");
        return FALSE;
    }

    parent_info->accept_mutex = ap_mpm_accept_mutex;

    /* Allocate shared memory for scoreboard */
    if (ap_scoreboard_image == NULL) {
        void *sb_mem;
        rc = DosAllocSharedMem(&sb_mem, ap_scoreboard_fname,
                               ap_calc_scoreboard_size(),
                               PAG_COMMIT|PAG_READ|PAG_WRITE);

        if (rc) {
            ap_log_error(APLOG_MARK, APLOG_ERR, APR_FROM_OS_ERROR(rc), ap_server_conf,
                         "unable to allocate shared memory for scoreboard , exiting");
            return FALSE;
        }

        ap_init_scoreboard(sb_mem);
    }

    ap_scoreboard_image->global->restart_time = apr_time_now();
    ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
		"%s configured -- resuming normal operations",
		ap_get_server_version());
    ap_log_error(APLOG_MARK, 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_DEBUG, 0, ap_server_conf,
		"AcceptMutex: %s (default: %s)",
		apr_proc_mutex_name(accept_mutex),
		apr_proc_mutex_defname());
#endif
    if (one_process) {
        ap_scoreboard_image->parent[0].pid = getpid();
        ap_mpm_child_main(pconf);
        return FALSE;
    }

    while (!restart_pending && !shutdown_pending) {
        RESULTCODES proc_rc;