source: unix.c @ 5be87b2

  /********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2004 Wilmer van der Gaast and others                *
  \********************************************************************/

/* Main file (Unix specific part)                                       */

/*
  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 with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 59 Temple Place,
  Suite 330, Boston, MA  02111-1307  USA
*/

#include "bitlbee.h"
#include "commands.h"
#include "crypting.h"
#include "protocols/nogaim.h"
#include "help.h"
#include "ipc.h"
#include <signal.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <pwd.h>

global_t global;        /* Against global namespace pollution */

static void sighandler( int signal );

int main( int argc, char *argv[], char **envp )
{
        int i = 0;
        char *old_cwd = NULL;
        struct sigaction sig, old;
        
        log_init();
        global.conf_file = g_strdup( CONF_FILE_DEF );
        global.conf = conf_load( argc, argv );
        if( global.conf == NULL )
                return( 1 );
        
        b_main_init();
        nogaim_init();
        
        srand( time( NULL ) ^ getpid() );
        global.helpfile = g_strdup( HELP_FILE );
        
        if( global.conf->runmode == RUNMODE_INETD )
        {
                i = bitlbee_inetd_init();
                log_message( LOGLVL_INFO, "Bitlbee %s starting in inetd mode.", BITLBEE_VERSION );

        }
        else if( global.conf->runmode == RUNMODE_DAEMON )
        {
                i = bitlbee_daemon_init();
                log_message( LOGLVL_INFO, "Bitlbee %s starting in daemon mode.", BITLBEE_VERSION );
        }
        else if( global.conf->runmode == RUNMODE_FORKDAEMON )
        {
                /* In case the operator requests a restart, we need this. */
                old_cwd = g_malloc( 256 );
                if( getcwd( old_cwd, 255 ) == NULL )
                {
                        log_message( LOGLVL_WARNING, "Could not save current directory: %s", strerror( errno ) );
                        g_free( old_cwd );
                        old_cwd = NULL;
                }
                
                i = bitlbee_daemon_init();
                log_message( LOGLVL_INFO, "Bitlbee %s starting in forking daemon mode.", BITLBEE_VERSION );
        }
        if( i != 0 )
                return( i );
        
        if( ( global.conf->user && *global.conf->user ) &&
            ( global.conf->runmode == RUNMODE_DAEMON || 
              global.conf->runmode == RUNMODE_FORKDAEMON ) &&
            ( !getuid() || !geteuid() ) )
        {
                struct passwd *pw = NULL;
                pw = getpwnam( global.conf->user );
                if( pw )
                {
                        setgid( pw->pw_gid );
                        setuid( pw->pw_uid );
                }
        }

        global.storage = storage_init( global.conf->primary_storage, global.conf->migrate_storage );
        if( global.storage == NULL )
        {
                log_message( LOGLVL_ERROR, "Unable to load storage backend '%s'", global.conf->primary_storage );
                return( 1 );
        }
        
        /* Catch some signals to tell the user what's happening before quitting */
        memset( &sig, 0, sizeof( sig ) );
        sig.sa_handler = sighandler;
        sigaction( SIGCHLD, &sig, &old );
        sigaction( SIGPIPE, &sig, &old );
        sig.sa_flags = SA_RESETHAND;
        sigaction( SIGINT,  &sig, &old );
        sigaction( SIGILL,  &sig, &old );
        sigaction( SIGBUS,  &sig, &old );
        sigaction( SIGFPE,  &sig, &old );
        sigaction( SIGSEGV, &sig, &old );
        sigaction( SIGTERM, &sig, &old );
        sigaction( SIGQUIT, &sig, &old );
        sigaction( SIGXCPU, &sig, &old );
        
        if( !getuid() || !geteuid() )
                log_message( LOGLVL_WARNING, "BitlBee is running with root privileges. Why?" );
        if( help_init( &global.help, global.helpfile ) == NULL )
                log_message( LOGLVL_WARNING, "Error opening helpfile %s.", HELP_FILE );
        
        b_main_run();
        
        /* Mainly good for restarting, to make sure we close the help.txt fd. */
        help_free( &global.help );
        
        if( global.restart )
        {
                char *fn = ipc_master_save_state();
                char **args;
                int n, i;
                
                chdir( old_cwd );
                
                n = 0;
                args = g_new0( char *, argc + 3 );
                args[n++] = argv[0];
                if( fn )
                {
                        args[n++] = "-R";
                        args[n++] = fn;
                }
                for( i = 1; argv[i] && i < argc; i ++ )
                {
                        if( strcmp( argv[i], "-R" ) == 0 )
                                i += 2;
                        
                        args[n++] = argv[i];
                }
                
                close( global.listen_socket );
                
                execve( args[0], args, envp );
        }
        
        return( 0 );
}

static void sighandler( int signal )
{
        /* FIXME: Calling log_message() here is not a very good idea! */
        
        if( signal == SIGTERM )
        {
                static int first = 1;
                
                if( first )
                {
                        /* We don't know what we were doing when this signal came in. It's not safe to touch
                           the user data now (not to mention writing them to disk), so add a timer. */
                        
                        log_message( LOGLVL_ERROR, "SIGTERM received, cleaning up process." );
                        b_timeout_add( 1, (b_event_handler) bitlbee_shutdown, NULL );
                        
                        first = 0;
                }
                else
                {
                        /* Well, actually, for now we'll never need this part because this signal handler
                           will never be called more than once in a session for a non-SIGPIPE signal...
                           But just in case we decide to change that: */
                        
                        log_message( LOGLVL_ERROR, "SIGTERM received twice, so long for a clean shutdown." );
                        raise( signal );
                }
        }
        else if( signal == SIGCHLD )
        {
                pid_t pid;
                int st;
                
                while( ( pid = waitpid( 0, &st, WNOHANG ) ) > 0 )
                {
                        if( WIFSIGNALED( st ) )
                                log_message( LOGLVL_INFO, "Client %d terminated normally. (status = %d)", (int) pid, WEXITSTATUS( st ) );
                        else if( WIFEXITED( st ) )
                                log_message( LOGLVL_INFO, "Client %d killed by signal %d.", (int) pid, WTERMSIG( st ) );
                }
        }
        else if( signal != SIGPIPE )
        {
                log_message( LOGLVL_ERROR, "Fatal signal received: %d. That's probably a bug.", signal );
                raise( signal );
        }
}

double gettime()
{
        struct timeval time[1];

        gettimeofday( time, 0 );
        return( (double) time->tv_sec + (double) time->tv_usec / 1000000 );
}

/* A pretty reliable random number generator. Tries to use the /dev/random
   devices first, and falls back to the random number generator from libc
   when it fails. Opens randomizer devices with O_NONBLOCK to make sure a
   lack of entropy won't halt BitlBee. */
void random_bytes( unsigned char *buf, int count )
{
        static int use_dev = -1;
        
        /* Actually this probing code isn't really necessary, is it? */
        if( use_dev == -1 )
        {
                if( access( "/dev/random", R_OK ) == 0 || access( "/dev/urandom", R_OK ) == 0 )
                        use_dev = 1;
                else
                {
                        use_dev = 0;
                        srand( ( getpid() << 16 ) ^ time( NULL ) );
                }
        }
        
        if( use_dev )
        {
                int fd;
                
                /* At least on Linux, /dev/random can block if there's not
                   enough entropy. We really don't want that, so if it can't
                   give anything, use /dev/urandom instead. */
                if( ( fd = open( "/dev/random", O_RDONLY | O_NONBLOCK ) ) >= 0 )
                        if( read( fd, buf, count ) == count )
                        {
                                close( fd );
                                return;
                        }
                close( fd );
                
                /* urandom isn't supposed to block at all, but just to be
                   sure. If it blocks, we'll disable use_dev and use the libc
                   randomizer instead. */
                if( ( fd = open( "/dev/urandom", O_RDONLY | O_NONBLOCK ) ) >= 0 )
                        if( read( fd, buf, count ) == count )
                        {
                                close( fd );
                                return;
                        }
                close( fd );
                
                /* If /dev/random blocks once, we'll still try to use it
                   again next time. If /dev/urandom also fails for some
                   reason, stick with libc during this session. */
                
                use_dev = 0;
                srand( ( getpid() << 16 ) ^ time( NULL ) );
        }
        
        if( !use_dev )
        {
                int i;
                
                /* Possibly the LSB of rand() isn't very random on some
                   platforms. Seems okay on at least Linux and OSX though. */
                for( i = 0; i < count; i ++ )
                        buf[i] = rand() & 0xff;
        }
}