src/gateway.c

/********************************************************************\
 * This program is free software; you can redistribute it and/or    *
 * modify it under the terms of the GNU General Public License as   *
 * published by the Free:Software Foundation; either version 2 of   *
 * the License, or (at your option) any later version.              *
 *                                                                  *
 * This program is distributed in the hope that it will be useful,  *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of   *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the    *
 * GNU General Public License for more details.                     *
 *                                                                  *
 * You should have received a copy of the GNU General Public License*
 * along with this program; if not, contact:                        *
 *                                                                  *
 * Free Software Foundation           Voice:  +1-617-542-5942       *
 * 59 Temple Place - Suite 330        Fax:    +1-617-542-2652       *
 * Boston, MA  02111-1307,  USA       gnu@gnu.org                   *
 *                                                                  *
 \********************************************************************/

/* $Header: /cvsroot/wifidog/wifidog/src/gateway.c,v 1.43 2005/03/12 22:16:38 minaguib Exp $ */
#include <stdio.h>
#include <stdlib.h>
#include <syslog.h>
#include <pthread.h>
#include <signal.h>
#include <errno.h>
#include <time.h>

/* for fork() */
#include <sys/types.h>
#include <unistd.h>

/* for strerror() */
#include <string.h>

/* for wait() */
#include <sys/wait.h>

#include "httpd.h"
#include "safe.h"
#include "debug.h"
#include "conf.h"
#include "gateway.h"
#include "firewall.h"
#include "commandline.h"
#include "auth.h"
#include "http.h"
#include "client_list.h"
#include "wdctl_thread.h"
#include "ping_thread.h"
#include "httpd_thread.h"
#include "util.h"

static pthread_t tid_fw_counter = 0;
static pthread_t tid_ping = 0; 

void
sigchld_handler(int s)
{
        int     status;
        
        wait(&status);
}

void
termination_handler(int s)
{
        static  pthread_mutex_t sigterm_mutex = PTHREAD_MUTEX_INITIALIZER;

        debug(LOG_INFO, "Caught signal %d", s);

        /* Makes sure we only call fw_destroy() once. */
        if (pthread_mutex_trylock(&sigterm_mutex)) {
                debug(LOG_INFO, "Another thread already began global termination handler. I'm exiting");
                pthread_exit(NULL);
        }
        else {
                debug(LOG_INFO, "Cleaning up and exiting");
        }

        debug(LOG_DEBUG, "Flushing firewall rules...");
        fw_destroy();

        /* XXX Hack
         * Aparently pthread_cond_timedwait under openwrt prevents signals (and therefore termination handler) from happening
         * so we need to explicitly kill the threads that use that
         */
        if (tid_fw_counter) {
                debug(LOG_INFO, "Explicitly killing the fw_counter thread");
                pthread_kill(tid_fw_counter, SIGKILL);
        }
        if (tid_ping) {
                debug(LOG_INFO, "Explicitly killing the ping thread");
                pthread_kill(tid_ping, SIGKILL);
        }

        debug(LOG_DEBUG, "Exiting...");
        exit(s == 0 ? 1 : 0);
}

static void
init_signals(void)
{
        struct sigaction sa;

        debug(LOG_DEBUG, "Initializing signal handlers");
        
        sa.sa_handler = sigchld_handler;
        sigemptyset(&sa.sa_mask);
        sa.sa_flags = SA_RESTART;
        if (sigaction(SIGCHLD, &sa, NULL) == -1) {
                debug(LOG_ERR, "sigaction(): %s", strerror(errno));
                exit(1);
        }

        /* Trap SIGPIPE */
        /* This is done so that when libhttpd does a socket operation on
         * a disconnected socket (i.e.: Broken Pipes) we catch the signal
         * and do nothing. The alternative is to exit. SIGPIPE are harmless
         * if not desirable.
         */
        sa.sa_handler = SIG_IGN;
        if (sigaction(SIGPIPE, &sa, NULL) == -1) {
                debug(LOG_ERR, "sigaction(): %s", strerror(errno));
                exit(1);
        }

        sa.sa_handler = termination_handler;
        sigemptyset(&sa.sa_mask);
        sa.sa_flags = SA_RESTART;

        /* Trap SIGTERM */
        if (sigaction(SIGTERM, &sa, NULL) == -1) {
                debug(LOG_ERR, "sigaction(): %s", strerror(errno));
                exit(1);
        }

        /* Trap SIGQUIT */
        if (sigaction(SIGQUIT, &sa, NULL) == -1) {
                debug(LOG_ERR, "sigaction(): %s", strerror(errno));
                exit(1);
        }

        /* Trap SIGINT */
        if (sigaction(SIGINT, &sa, NULL) == -1) {
                debug(LOG_ERR, "sigaction(): %s", strerror(errno));
                exit(1);
        }
}

static void
main_loop(void)
{
        httpd * webserver;
        int result;
        pthread_t       tid;
        s_config *config = config_get_config();
        request *r;
        void **params;

        /* Initializes the linked list of connected clients */
        client_list_init();

    /* If we don't have the Gateway IP address, get it. Can't fail. */
    if (!config->gw_address) {
        debug(LOG_DEBUG, "Finding IP address of %s", config->gw_interface);
        if ((config->gw_address = get_iface_ip(config->gw_interface)) == NULL) {
                    debug(LOG_ERR, "Could not get IP address information of %s, exiting...", config->gw_interface);
            exit(1);
        }
        debug(LOG_DEBUG, "%s = %s", config->gw_interface, config->gw_address);
    }

        /* Initializes the web server */
        debug(LOG_NOTICE, "Creating web server on %s:%d", 
                        config->gw_address, config->gw_port);
        webserver = httpdCreate(config->gw_address, config->gw_port);
        if (webserver == NULL) {
                debug(LOG_ERR, "Could not create web server: %s",
                                strerror(errno));
                exit(1);
        }
        debug(LOG_DEBUG, "Assigning callbacks to web server");
        httpdAddCContent(webserver, "/", "wifidog", 0, NULL, http_callback_wifidog);
        httpdAddCContent(webserver, "/wifidog", "", 0, NULL, http_callback_wifidog);
        httpdAddCContent(webserver, "/wifidog", "about", 0, NULL, http_callback_about);
        httpdAddCContent(webserver, "/wifidog", "status", 0, NULL, http_callback_status);
        httpdAddCContent(webserver, "/wifidog", "auth", 0, NULL, http_callback_auth);
        httpdAddC404Content(webserver, http_callback_404);

        /* Init the signals to catch chld/quit/etc */
        init_signals();

        /* Reset the firewall (if WiFiDog crashed) */
        fw_destroy();
        fw_init();

        /* start clean up thread */
        result = pthread_create(&tid_fw_counter, NULL, (void *)thread_client_timeout_check, NULL);
        if (result != 0) {
                debug(LOG_ERR, "FATAL: Failed to create a new thread (fw_counter) - exiting");
                termination_handler(0);
        }
        pthread_detach(tid_fw_counter);

        /* start control thread */
        result = pthread_create(&tid, NULL, (void *)thread_wdctl, (void *)safe_strdup(config->wdctl_sock));
        if (result != 0) {
                debug(LOG_ERR, "FATAL: Failed to create a new thread (wdctl) - exiting");
                termination_handler(0);
        }
        pthread_detach(tid);
        
        /* start heartbeat thread */
        result = pthread_create(&tid_ping, NULL, (void *)thread_ping, NULL);
        if (result != 0) {
                debug(LOG_ERR, "FATAL: Failed to create a new thread (ping) - exiting");
                termination_handler(0);
        }
        pthread_detach(tid_ping);
        
        debug(LOG_NOTICE, "Waiting for connections");
        while(1) {
                r = httpdGetConnection(webserver, NULL);

                /* We can't convert this to a switch because there might be
                 * values that are not -1, 0 or 1. */
                if (webserver->lastError == -1) {
                        /* Interrupted system call */
                        continue; /* restart loop */
                }
                else if (webserver->lastError < -1) {
                        /*
                         * FIXME
                         * An error occurred - should we abort?
                         * reboot the device ?
                         */
                        debug(LOG_ERR, "FATAL: httpdGetConnection returned unexpected value %d, exiting.", webserver->lastError);
                        termination_handler(0);
                }
                else if (r != NULL) {
                        /*
                         * We got a connection
                         *
                         * We should fork another thread
                         */
                        debug(LOG_INFO, "Received connection from %s, spawning worker thread", r->clientAddr);
                        /* The void**'s are a simulation of the normal C
                         * function calling sequence. */
                        params = safe_malloc(2 * sizeof(void *));
                        *params = webserver;
                        *(params + 1) = r;

                        result = pthread_create(&tid, NULL, (void *)thread_httpd, (void *)params);
                        if (result != 0) {
                                debug(LOG_ERR, "FATAL: Failed to create a new thread (httpd) - exiting");
                                termination_handler(0);
                        }
                        pthread_detach(tid);
                }
                else {
                        /* webserver->lastError should be 2 */
                        /* XXX We failed an ACL.... No handling because
                         * we don't set any... */
                }
        }

        /* never reached */
}

int
main(int argc, char **argv)
{
        s_config *config = config_get_config();
        config_init();

        parse_commandline(argc, argv);

        config_read(config->configfile);
        config_validate();

        if (config->daemon) {

                debug(LOG_INFO, "Forking into background");

                switch(fork()) {
                case -1: /* error */
                        debug(LOG_ERR, "fork(): %s", strerror(errno));
                        exit(1);
                        break;

                case 0: /* parent */
                        main_loop();
                        break;

                default: /* child */
                        exit(0);
                        break;
                }
        } else {
                main_loop();
        }

        return(0); /* never reached */
}

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