source: ipc.c @ ecbd22a

  /********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2012 Wilmer van der Gaast and others                *
  \********************************************************************/

/* IPC - communication between BitlBee processes                        */

/*
  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., 51 Franklin St.,
  Fifth Floor, Boston, MA  02110-1301  USA
*/

#define BITLBEE_CORE
#include "bitlbee.h"
#include "ipc.h"
#include "commands.h"
#include <sys/uio.h>
#include <sys/un.h>

GSList *child_list = NULL;
static int ipc_child_recv_fd = -1;

static void ipc_master_takeover_fail( struct bitlbee_child *child, gboolean both );
static gboolean ipc_send_fd( int fd, int send_fd );

/* On Solaris and possibly other systems passing FDs between processes is
 * not possible (or at least not using the method used in this file.
 * Just disable that code, the functionality is not that important. */
#if defined(NO_FD_PASSING) && !defined(CMSG_SPACE)
#define CMSG_SPACE(len) 1
#endif

static void ipc_master_cmd_client( irc_t *data, char **cmd )
{
        /* Normally data points at an irc_t block, but for the IPC master
           this is different. We think this scary cast is better than
           creating a new command_t structure, just to make the compiler
           happy. */
        struct bitlbee_child *child = (void*) data;
        
        if( child && cmd[1] )
        {
                child->host = g_strdup( cmd[1] );
                child->nick = g_strdup( cmd[2] );
                child->realname = g_strdup( cmd[3] );
        }
        
        /* CLIENT == On initial connects, HELLO is after /RESTARTs. */
        if( g_strcasecmp( cmd[0], "CLIENT" ) == 0 )
                ipc_to_children_str( "OPERMSG :Client connecting (PID=%d): %s@%s (%s)\r\n",
                                     (int) ( child ? child->pid : -1 ), cmd[2], cmd[1], cmd[3] );
}

static void ipc_master_cmd_nick( irc_t *data, char **cmd )
{
        struct bitlbee_child *child = (void*) data;
        
        if( child && cmd[1] )
        {
                g_free( child->nick );
                child->nick = g_strdup( cmd[1] );
        }
}

static void ipc_master_cmd_die( irc_t *data, char **cmd )
{
        if( global.conf->runmode == RUNMODE_FORKDAEMON )
                ipc_to_children_str( "DIE\r\n" );
        
        bitlbee_shutdown( NULL, -1, 0 );
}

static void ipc_master_cmd_deaf( irc_t *data, char **cmd )
{
        if( global.conf->runmode == RUNMODE_DAEMON )
        {
                b_event_remove( global.listen_watch_source_id );
                close( global.listen_socket );
                
                global.listen_socket = global.listen_watch_source_id = -1;
        
                ipc_to_children_str( "OPERMSG :Closed listening socket, waiting "
                                     "for all users to disconnect." );
        }
        else
        {
                ipc_to_children_str( "OPERMSG :The DEAF command only works in "
                                     "normal daemon mode. Try DIE instead." );
        }
}

void ipc_master_cmd_rehash( irc_t *data, char **cmd )
{
        runmode_t oldmode;
        
        oldmode = global.conf->runmode;
        
        g_free( global.conf );
        global.conf = conf_load( 0, NULL );
        
        if( global.conf->runmode != oldmode )
        {
                log_message( LOGLVL_WARNING, "Can't change RunMode setting at runtime, restoring original setting" );
                global.conf->runmode = oldmode;
        }
        
        if( global.conf->runmode == RUNMODE_FORKDAEMON )
                ipc_to_children( cmd );
}

void ipc_master_cmd_restart( irc_t *data, char **cmd )
{
        if( global.conf->runmode != RUNMODE_FORKDAEMON )
        {
                /* Tell child that this is unsupported. */
                return;
        }
        
        global.restart = -1;
        bitlbee_shutdown( NULL, -1, 0 );
}

void ipc_master_cmd_identify( irc_t *data, char **cmd )
{
        struct bitlbee_child *child = (void*) data, *old = NULL;
        char *resp;
        GSList *l;
        
        if( !child || !child->nick || strcmp( child->nick, cmd[1] ) != 0 )
                return;
        
        g_free( child->password );
        child->password = g_strdup( cmd[2] );
        
        for( l = child_list; l; l = l->next )
        {
                old = l->data;
                if( child != old &&
                    old->nick && nick_cmp( NULL, old->nick, child->nick ) == 0 &&
                    old->password && strcmp( old->password, child->password ) == 0 )
                        break;
        }
        
        if( l && !child->to_child && !old->to_child )
        {
                resp = "TAKEOVER INIT\r\n";
                child->to_child = old;
                old->to_child = child;
        }
        else
        {
                /* Won't need the fd since we can't send it anywhere. */
                closesocket( child->to_fd );
                child->to_fd = -1;
                resp = "TAKEOVER NO\r\n";
        }
        
        if( write( child->ipc_fd, resp, strlen( resp ) ) != strlen( resp ) )
                ipc_master_free_one( child );
}


void ipc_master_cmd_takeover( irc_t *data, char **cmd )
{
        struct bitlbee_child *child = (void*) data;
        char *fwd = NULL;
        
        /* Normal daemon mode doesn't keep these and has simplified code for
           takeovers. */
        if( child == NULL )
                return;
        
        if( child->to_child == NULL ||
            g_slist_find( child_list, child->to_child ) == NULL )
                return ipc_master_takeover_fail( child, FALSE );
        
        if( strcmp( cmd[1], "AUTH" ) == 0 )
        {
                /* New connection -> Master */
                if( child->to_child &&
                    child->nick && child->to_child->nick && cmd[2] &&
                    child->password && child->to_child->password && cmd[3] &&
                    strcmp( child->nick, child->to_child->nick ) == 0 &&
                    strcmp( child->nick, cmd[2] ) == 0 &&
                    strcmp( child->password, child->to_child->password ) == 0 &&
                    strcmp( child->password, cmd[3] ) == 0 )
                {
                        ipc_send_fd( child->to_child->ipc_fd, child->to_fd );
                        
                        fwd = irc_build_line( cmd );
                        if( write( child->to_child->ipc_fd, fwd, strlen( fwd ) ) != strlen( fwd ) )
                                ipc_master_free_one( child );
                        g_free( fwd );
                }
                else
                        return ipc_master_takeover_fail( child, TRUE );
        }
        else if( strcmp( cmd[1], "DONE" ) == 0 || strcmp( cmd[1], "FAIL" ) == 0 )
        {
                /* Old connection -> Master */
                int fd;
                
                /* The copy was successful (or not), we don't need it anymore. */
                closesocket( child->to_fd );
                child->to_fd = -1;
                
                /* Pass it through to the other party, and flush all state. */
                fwd = irc_build_line( cmd );
                fd = child->to_child->ipc_fd;
                child->to_child->to_child = NULL;
                child->to_child = NULL;
                if( write( fd, fwd, strlen( fwd ) ) != strlen( fwd ) )
                        ipc_master_free_one( child );
                g_free( fwd );
        }
}

static const command_t ipc_master_commands[] = {
        { "client",     3, ipc_master_cmd_client,     0 },
        { "hello",      0, ipc_master_cmd_client,     0 },
        { "nick",       1, ipc_master_cmd_nick,       0 },
        { "die",        0, ipc_master_cmd_die,        0 },
        { "deaf",       0, ipc_master_cmd_deaf,       0 },
        { "wallops",    1, NULL,                      IPC_CMD_TO_CHILDREN },
        { "wall",       1, NULL,                      IPC_CMD_TO_CHILDREN },
        { "opermsg",    1, NULL,                      IPC_CMD_TO_CHILDREN },
        { "rehash",     0, ipc_master_cmd_rehash,     0 },
        { "kill",       2, NULL,                      IPC_CMD_TO_CHILDREN },
        { "restart",    0, ipc_master_cmd_restart,    0 },
        { "identify",   2, ipc_master_cmd_identify,   0 },
        { "takeover",   1, ipc_master_cmd_takeover,   0 },
        { NULL }
};


static void ipc_child_cmd_die( irc_t *irc, char **cmd )
{
        irc_abort( irc, 0, "Shutdown requested by operator" );
}

static void ipc_child_cmd_wallops( irc_t *irc, char **cmd )
{
        if( !( irc->status & USTATUS_LOGGED_IN ) )
                return;
        
        if( strchr( irc->umode, 'w' ) )
                irc_write( irc, ":%s WALLOPS :%s", irc->root->host, cmd[1] );
}

static void ipc_child_cmd_wall( irc_t *irc, char **cmd )
{
        if( !( irc->status & USTATUS_LOGGED_IN ) )
                return;
        
        if( strchr( irc->umode, 's' ) )
                irc_write( irc, ":%s NOTICE %s :%s", irc->root->host, irc->user->nick, cmd[1] );
}

static void ipc_child_cmd_opermsg( irc_t *irc, char **cmd )
{
        if( !( irc->status & USTATUS_LOGGED_IN ) )
                return;
        
        if( strchr( irc->umode, 'o' ) )
                irc_write( irc, ":%s NOTICE %s :*** OperMsg *** %s", irc->root->host, irc->user->nick, cmd[1] );
}

static void ipc_child_cmd_rehash( irc_t *irc, char **cmd )
{
        runmode_t oldmode;
        
        oldmode = global.conf->runmode;
        
        g_free( global.conf );
        global.conf = conf_load( 0, NULL );
        
        global.conf->runmode = oldmode;
}

static void ipc_child_cmd_kill( irc_t *irc, char **cmd )
{
        if( !( irc->status & USTATUS_LOGGED_IN ) )
                return;
        
        if( nick_cmp( NULL, cmd[1], irc->user->nick ) != 0 )
                return;         /* It's not for us. */
        
        irc_write( irc, ":%s!%s@%s KILL %s :%s", irc->root->nick, irc->root->nick, irc->root->host, irc->user->nick, cmd[2] );
        irc_abort( irc, 0, "Killed by operator: %s", cmd[2] );
}

static void ipc_child_cmd_hello( irc_t *irc, char **cmd )
{
        if( !( irc->status & USTATUS_LOGGED_IN ) )
                ipc_to_master_str( "HELLO\r\n" );
        else
                ipc_to_master_str( "HELLO %s %s :%s\r\n", irc->user->host, irc->user->nick, irc->user->fullname );
}

static void ipc_child_cmd_takeover_yes( void *data );
static void ipc_child_cmd_takeover_no( void *data );

static void ipc_child_cmd_takeover( irc_t *irc, char **cmd )
{
        if( strcmp( cmd[1], "NO" ) == 0 )
        {
                /* Master->New connection */
                /* No takeover, finish the login. */
        }
        else if( strcmp( cmd[1], "INIT" ) == 0 )
        {
                /* Master->New connection */
                if( !set_getbool( &irc->b->set, "allow_takeover" ) )
                {
                        ipc_child_cmd_takeover_no( irc );
                        return;
                }
                
                /* Offer to take over the old session, unless for some reason
                   we're already logging into IM connections. */
                if( irc->login_source_id != -1 )
                        query_add( irc, NULL,
                                   "You're already connected to this server. "
                                   "Would you like to take over this session?",
                                   ipc_child_cmd_takeover_yes,
                                   ipc_child_cmd_takeover_no, NULL, irc );
                
                /* This one's going to connect to accounts, avoid that. */
                b_event_remove( irc->login_source_id );
                irc->login_source_id = -1;
        }
        else if( strcmp( cmd[1], "AUTH" ) == 0 )
        {
                /* Master->Old connection */
                if( irc->password && cmd[2] && cmd[3] &&
                    ipc_child_recv_fd != -1 &&
                    strcmp( irc->user->nick, cmd[2] ) == 0 &&
                    strcmp( irc->password, cmd[3] ) == 0 &&
                    set_getbool( &irc->b->set, "allow_takeover" ) )
                {
                        irc_switch_fd( irc, ipc_child_recv_fd );
                        irc_sync( irc );
                        irc_rootmsg( irc, "You've successfully taken over your old session" );
                        ipc_child_recv_fd = -1;
                        
                        ipc_to_master_str( "TAKEOVER DONE\r\n" );
                }
                else
                {
                        ipc_to_master_str( "TAKEOVER FAIL\r\n" );
                }
        }
        else if( strcmp( cmd[1], "DONE" ) == 0 ) 
        {
                /* Master->New connection (now taken over by old process) */
                irc_free( irc );
        }
        else if( strcmp( cmd[1], "FAIL" ) == 0 ) 
        {
                /* Master->New connection */
                irc_rootmsg( irc, "Could not take over old session" );
        }
}

static void ipc_child_cmd_takeover_yes( void *data )
{
        irc_t *irc = data, *old = NULL;
        char *to_auth[] = { "TAKEOVER", "AUTH", irc->user->nick, irc->password, NULL };
        
        /* Master->New connection */
        ipc_to_master_str( "TAKEOVER AUTH %s :%s\r\n",
                           irc->user->nick, irc->password );
        
        if( global.conf->runmode == RUNMODE_DAEMON )
        {
                GSList *l;
                
                for( l = irc_connection_list; l; l = l->next )
                {
                        old = l->data;
                        
                        if( irc != old &&
                            irc->user->nick && old->user->nick &&
                            irc->password && old->password &&
                            strcmp( irc->user->nick, old->user->nick ) == 0 &&
                            strcmp( irc->password, old->password ) == 0 )
                                break;
                }
                if( l == NULL )
                {
                        to_auth[1] = "FAIL";
                        ipc_child_cmd_takeover( irc, to_auth );
                        return;
                }
        }
        
        /* Drop credentials, we'll shut down soon and shouldn't overwrite
           any settings. */
        irc_rootmsg( irc, "Trying to take over existing session" );
        
        irc_desync( irc );
        
        if( old )
        {
                ipc_child_recv_fd = dup( irc->fd );
                ipc_child_cmd_takeover( old, to_auth );
        }
        
        /* TODO: irc_setpass() should do all of this. */
        irc_setpass( irc, NULL );
        irc->status &= ~USTATUS_IDENTIFIED;
        irc_umode_set( irc, "-R", 1 );
        
        if( old )
                irc_abort( irc, FALSE, NULL );
}

static void ipc_child_cmd_takeover_no( void *data )
{
        ipc_to_master_str( "TAKEOVER NO\r\n" );
        cmd_identify_finish( data, 0, 0 );
}

static const command_t ipc_child_commands[] = {
        { "die",        0, ipc_child_cmd_die,         0 },
        { "wallops",    1, ipc_child_cmd_wallops,     0 },
        { "wall",       1, ipc_child_cmd_wall,        0 },
        { "opermsg",    1, ipc_child_cmd_opermsg,     0 },
        { "rehash",     0, ipc_child_cmd_rehash,      0 },
        { "kill",       2, ipc_child_cmd_kill,        0 },
        { "hello",      0, ipc_child_cmd_hello,       0 },
        { "takeover",   1, ipc_child_cmd_takeover,    0 },
        { NULL }
};

gboolean ipc_child_identify( irc_t *irc )
{
        if( global.conf->runmode == RUNMODE_FORKDAEMON )
        {
#ifndef NO_FD_PASSING
                if( !ipc_send_fd( global.listen_socket, irc->fd ) )
                        ipc_child_disable();
        
                ipc_to_master_str( "IDENTIFY %s :%s\r\n", irc->user->nick, irc->password );
#endif
                
                return TRUE;
        }
        else if( global.conf->runmode == RUNMODE_DAEMON )
        {
                GSList *l;
                irc_t *old = NULL;
                char *to_init[] = { "TAKEOVER", "INIT", NULL };
                
                for( l = irc_connection_list; l; l = l->next )
                {
                        old = l->data;
                        
                        if( irc != old &&
                            irc->user->nick && old->user->nick &&
                            irc->password && old->password &&
                            strcmp( irc->user->nick, old->user->nick ) == 0 &&
                            strcmp( irc->password, old->password ) == 0 )
                                break;
                }
                if( l == NULL || old == NULL ||
                    !set_getbool( &irc->b->set, "allow_takeover" ) ||
                    !set_getbool( &old->b->set, "allow_takeover" ) )
                        return FALSE;
                
                ipc_child_cmd_takeover( irc, to_init );
                
                return TRUE;
        }
        else
                return FALSE;
}

static void ipc_master_takeover_fail( struct bitlbee_child *child, gboolean both )
{
        if( child == NULL || g_slist_find( child_list, child ) == NULL )
                return;
        
        if( both && child->to_child != NULL )
                ipc_master_takeover_fail( child->to_child, FALSE );
        
        if( child->to_fd > -1 )
        {
                /* Send this error only to the new connection, which can be
                   recognised by to_fd being set. */
                if( write( child->ipc_fd, "TAKEOVER FAIL\r\n", 15 ) != 15 )
                {
                        ipc_master_free_one( child );
                        return;
                }
                close( child->to_fd );
                child->to_fd = -1;
        }
        child->to_child = NULL;
}

static void ipc_command_exec( void *data, char **cmd, const command_t *commands )
{
        int i, j;
        
        if( !cmd[0] )
                return;
        
        for( i = 0; commands[i].command; i ++ )
                if( g_strcasecmp( commands[i].command, cmd[0] ) == 0 )
                {
                        /* There is no typo in this line: */
                        for( j = 1; cmd[j]; j ++ )
                                ;
                        j--;
                        
                        if( j < commands[i].required_parameters )
                                break;
                        
                        if( commands[i].flags & IPC_CMD_TO_CHILDREN )
                                ipc_to_children( cmd );
                        else
                                commands[i].execute( data, cmd );
                        
                        break;
                }
}

/* Return just one line. Returns NULL if something broke, an empty string
   on temporary "errors" (EAGAIN and friends). */
static char *ipc_readline( int fd, int *recv_fd )
{
        struct msghdr msg;
        struct iovec iov;
        char ccmsg[CMSG_SPACE(sizeof(recv_fd))];
        struct cmsghdr *cmsg;
        char buf[513], *eol;
        int size;
        
        /* Because this is internal communication, it should be pretty safe
           to just peek at the message, find its length (by searching for the
           end-of-line) and then just read that message. With internal
           sockets and limites message length, messages should always be
           complete. Saves us quite a lot of code and buffering. */
        size = recv( fd, buf, sizeof( buf ) - 1, MSG_PEEK );
        if( size == 0 || ( size < 0 && !sockerr_again() ) )
                return NULL;
        else if( size < 0 ) /* && sockerr_again() */
                return( g_strdup( "" ) );
        else
                buf[size] = 0;
        
        if( ( eol = strstr( buf, "\r\n" ) ) == NULL )
                return NULL;
        else
                size = eol - buf + 2;
        
        iov.iov_base = buf;
        iov.iov_len = size;
        
        memset( &msg, 0, sizeof( msg ) );
        msg.msg_iov = &iov;
        msg.msg_iovlen = 1;
#ifndef NO_FD_PASSING
        msg.msg_control = ccmsg;
        msg.msg_controllen = sizeof( ccmsg );
#endif
        
        if( recvmsg( fd, &msg, 0 ) != size )
                return NULL;
        
#ifndef NO_FD_PASSING
        if( recv_fd )
                for( cmsg = CMSG_FIRSTHDR( &msg ); cmsg; cmsg = CMSG_NXTHDR( &msg, cmsg ) )
                        if( cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS )
                        {
                                /* Getting more than one shouldn't happen but if it does,
                                   make sure we don't leave them around. */
                                if( *recv_fd != -1 )
                                        close( *recv_fd );
                                
                                *recv_fd = *(int*) CMSG_DATA( cmsg );
                                /*
                                fprintf( stderr, "pid %d received fd %d\n", (int) getpid(), *recv_fd );
                                */
                        }
#endif
        
        /*
        fprintf( stderr, "pid %d received: %s", (int) getpid(), buf );
        */
        return g_strndup( buf, size - 2 );
}

gboolean ipc_master_read( gpointer data, gint source, b_input_condition cond )
{
        struct bitlbee_child *child = data;
        char *buf, **cmd;
        
        if( ( buf = ipc_readline( source, &child->to_fd ) ) )
        {
                cmd = irc_parse_line( buf );
                if( cmd )
                {
                        ipc_command_exec( child, cmd, ipc_master_commands );
                        g_free( cmd );
                }
                g_free( buf );
        }
        else
        {
                ipc_master_free_fd( source );
        }
        
        return TRUE;
}

gboolean ipc_child_read( gpointer data, gint source, b_input_condition cond )
{
        char *buf, **cmd;
        
        if( ( buf = ipc_readline( source, &ipc_child_recv_fd ) ) )
        {
                cmd = irc_parse_line( buf );
                if( cmd )
                {
                        ipc_command_exec( data, cmd, ipc_child_commands );
                        g_free( cmd );
                }
                g_free( buf );
        }
        else
        {
                ipc_child_disable();
        }
        
        return TRUE;
}

void ipc_to_master( char **cmd )
{
        if( global.conf->runmode == RUNMODE_FORKDAEMON )
        {
                char *s = irc_build_line( cmd );
                ipc_to_master_str( "%s", s );
                g_free( s );
        }
        else if( global.conf->runmode == RUNMODE_DAEMON )
        {
                ipc_command_exec( NULL, cmd, ipc_master_commands );
        }
}

void ipc_to_master_str( char *format, ... )
{
        char *msg_buf;
        va_list params;

        va_start( params, format );
        msg_buf = g_strdup_vprintf( format, params );
        va_end( params );
        
        if( strlen( msg_buf ) > 512 )
        {
                /* Don't send it, it's too long... */
        }
        else if( global.conf->runmode == RUNMODE_FORKDAEMON )
        {
                if( global.listen_socket >= 0 )
                        if( write( global.listen_socket, msg_buf, strlen( msg_buf ) ) <= 0 )
                                ipc_child_disable();
        }
        else if( global.conf->runmode == RUNMODE_DAEMON )
        {
                char **cmd, *s;
                
                if( ( s = strchr( msg_buf, '\r' ) ) )
                        *s = 0;
                
                cmd = irc_parse_line( msg_buf );
                ipc_command_exec( NULL, cmd, ipc_master_commands );
                g_free( cmd );
        }
        
        g_free( msg_buf );
}

void ipc_to_children( char **cmd )
{
        if( global.conf->runmode == RUNMODE_FORKDAEMON )
        {
                char *msg_buf = irc_build_line( cmd );
                ipc_to_children_str( "%s", msg_buf );
                g_free( msg_buf );
        }
        else if( global.conf->runmode == RUNMODE_DAEMON )
        {
                GSList *l;
                
                for( l = irc_connection_list; l; l = l->next )
                        ipc_command_exec( l->data, cmd, ipc_child_commands );
        }
}

void ipc_to_children_str( char *format, ... )
{
        char *msg_buf;
        va_list params;

        va_start( params, format );
        msg_buf = g_strdup_vprintf( format, params );
        va_end( params );
        
        if( strlen( msg_buf ) > 512 )
        {
                /* Don't send it, it's too long... */
        }
        else if( global.conf->runmode == RUNMODE_FORKDAEMON )
        {
                int msg_len = strlen( msg_buf );
                GSList *l, *next;
                
                for( l = child_list; l; l = next )
                {
                        struct bitlbee_child *c = l->data;
                        
                        next = l->next;
                        if( write( c->ipc_fd, msg_buf, msg_len ) <= 0 )
                                ipc_master_free_one( c );
                }
        }
        else if( global.conf->runmode == RUNMODE_DAEMON )
        {
                char **cmd, *s;
                
                if( ( s = strchr( msg_buf, '\r' ) ) )
                        *s = 0;
                
                cmd = irc_parse_line( msg_buf );
                ipc_to_children( cmd );
                g_free( cmd );
        }
        
        g_free( msg_buf );
}

static gboolean ipc_send_fd( int fd, int send_fd )
{
        struct msghdr msg;
        struct iovec iov;
        char ccmsg[CMSG_SPACE(sizeof(fd))];
        struct cmsghdr *cmsg;
        
        memset( &msg, 0, sizeof( msg ) );
        iov.iov_base = "0x90\r\n";         /* Ja, noppes */
        iov.iov_len = 6;
        msg.msg_iov = &iov;
        msg.msg_iovlen = 1;
        
#ifndef NO_FD_PASSING
        msg.msg_control = ccmsg;
        msg.msg_controllen = sizeof( ccmsg );
        cmsg = CMSG_FIRSTHDR( &msg );
        cmsg->cmsg_level = SOL_SOCKET;
        cmsg->cmsg_type = SCM_RIGHTS;
        cmsg->cmsg_len = CMSG_LEN( sizeof( send_fd ) );
        *(int*)CMSG_DATA( cmsg ) = send_fd;
        msg.msg_controllen = cmsg->cmsg_len;
#endif
        
        return sendmsg( fd, &msg, 0 ) == 6;
}

void ipc_master_free_one( struct bitlbee_child *c )
{
        GSList *l;
        
        b_event_remove( c->ipc_inpa );
        closesocket( c->ipc_fd );
        
        if( c->to_fd != -1 )
                close( c->to_fd );
        
        g_free( c->host );
        g_free( c->nick );
        g_free( c->realname );
        g_free( c->password );
        g_free( c );
        
        child_list = g_slist_remove( child_list, c );
        
        /* Also, if any child has a reference to this one, remove it. */
        for( l = child_list; l; l = l->next )
        {
                struct bitlbee_child *oc = l->data;
                
                if( oc->to_child == c )
                        ipc_master_takeover_fail( oc, FALSE );
        }
}

void ipc_master_free_fd( int fd )
{
        GSList *l;
        struct bitlbee_child *c;
        
        for( l = child_list; l; l = l->next )
        {
                c = l->data;
                if( c->ipc_fd == fd )
                {
                        ipc_master_free_one( c );
                        break;
                }
        }
}

void ipc_master_free_all()
{
        while( child_list )
                ipc_master_free_one( child_list->data );
}

void ipc_child_disable()
{
        b_event_remove( global.listen_watch_source_id );
        close( global.listen_socket );
        
        global.listen_socket = -1;
}

char *ipc_master_save_state()
{
        char *fn = g_strdup( "/tmp/bee-restart.XXXXXX" );
        int fd = mkstemp( fn );
        GSList *l;
        FILE *fp;
        int i;
        
        if( fd == -1 )
        {
                log_message( LOGLVL_ERROR, "Could not create temporary file: %s", strerror( errno ) );
                g_free( fn );
                return NULL;
        }
        
        /* This is more convenient now. */
        fp = fdopen( fd, "w" );
        
        for( l = child_list, i = 0; l; l = l->next )
                i ++;
        
        /* Number of client processes. */
        fprintf( fp, "%d\n", i );
        
        for( l = child_list; l; l = l->next )
                fprintf( fp, "%d %d\n", (int) ((struct bitlbee_child*)l->data)->pid,
                                        ((struct bitlbee_child*)l->data)->ipc_fd );
        
        if( fclose( fp ) == 0 )
        {
                return fn;
        }
        else
        {
                unlink( fn );
                g_free( fn );
                return NULL;
        }
}


static gboolean new_ipc_client( gpointer data, gint serversock, b_input_condition cond )
{
        struct bitlbee_child *child = g_new0( struct bitlbee_child, 1 );
        
        child->to_fd = -1;
        child->ipc_fd = accept( serversock, NULL, 0 );
        if( child->ipc_fd == -1 )
        {
                log_message( LOGLVL_WARNING, "Unable to accept connection on UNIX domain socket: %s", strerror(errno) );
                return TRUE;
        }
                
        child->ipc_inpa = b_input_add( child->ipc_fd, B_EV_IO_READ, ipc_master_read, child );
        
        child_list = g_slist_prepend( child_list, child );
        
        return TRUE;
}

int ipc_master_listen_socket()
{
        struct sockaddr_un un_addr;
        int serversock;

        if (!IPCSOCKET || !*IPCSOCKET)
                return 1;

        /* Clean up old socket files that were hanging around.. */
        if (unlink(IPCSOCKET) == -1 && errno != ENOENT) {
                log_message( LOGLVL_ERROR, "Could not remove old IPC socket at %s: %s", IPCSOCKET, strerror(errno) );
                return 0;
        }

        un_addr.sun_family = AF_UNIX;
        strcpy(un_addr.sun_path, IPCSOCKET);

        serversock = socket(AF_UNIX, SOCK_STREAM, PF_UNIX);

        if (serversock == -1) {
                log_message( LOGLVL_WARNING, "Unable to create UNIX socket: %s", strerror(errno) );
                return 0;
        }

        if (bind(serversock, (struct sockaddr *)&un_addr, sizeof(un_addr)) == -1) {
                log_message( LOGLVL_WARNING, "Unable to bind UNIX socket to %s: %s", IPCSOCKET, strerror(errno) );
                return 0;
        }

        if (listen(serversock, 5) == -1) {
                log_message( LOGLVL_WARNING, "Unable to listen on UNIX socket: %s", strerror(errno) );
                return 0;
        }
        
        b_input_add( serversock, B_EV_IO_READ, new_ipc_client, NULL );
        
        return 1;
}

int ipc_master_load_state( char *statefile )
{
        struct bitlbee_child *child;
        FILE *fp;
        int i, n;
        
        if( statefile == NULL )
                return 0;
        
        fp = fopen( statefile, "r" );
        unlink( statefile );    /* Why do it later? :-) */
        if( fp == NULL )
                return 0;
        
        if( fscanf( fp, "%d", &n ) != 1 )
        {
                log_message( LOGLVL_WARNING, "Could not import state information for child processes." );
                fclose( fp );
                return 0;
        }
        
        log_message( LOGLVL_INFO, "Importing information for %d child processes.", n );
        for( i = 0; i < n; i ++ )
        {
                child = g_new0( struct bitlbee_child, 1 );
                
                if( fscanf( fp, "%d %d", (int *) &child->pid, &child->ipc_fd ) != 2 )
                {
                        log_message( LOGLVL_WARNING, "Unexpected end of file: Only processed %d clients.", i );
                        g_free( child );
                        fclose( fp );
                        return 0;
                }
                child->ipc_inpa = b_input_add( child->ipc_fd, B_EV_IO_READ, ipc_master_read, child );
                child->to_fd = -1;
                
                child_list = g_slist_prepend( child_list, child );
        }
        
        ipc_to_children_str( "HELLO\r\n" );
        ipc_to_children_str( "OPERMSG :New %s master process started (version %s)\r\n", PACKAGE, BITLBEE_VERSION );
        
        fclose( fp );
        return 1;
}