kill.c

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/*
 * $Id: kill.c 4518 2008-07-28 15:39:28Z henningw $
 *
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio 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
 *
 * Kamailio 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, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * History:
 * --------
 *  2003-03-11  changed to the new locking scheme: locking.h (andrei)
 *
 *
 * in this file, we implement the ability to send a kill signal to
 * a child after some time; its a quick ugly hack, for example kill
 * is sent without any knowledge whether the kid is still alive
 *
 * also, it was never compiled without FAST_LOCK -- nothing will
 * work if you turn it off
 *
 * there is also an ugly s/HACK
 *
 * and last but not least -- we don't know the child pid (we use popen)
 * so we cannot close anyway
 *
 *
 */


#include <errno.h>
#include <sys/types.h>
#include <signal.h>

#include "../../mem/shm_mem.h" 
#include "../../dprint.h"
#include "../../timer.h"
#include "../../locking.h"

#include "kill.h"


static gen_lock_t *kill_lock=NULL;


static struct timer_list kill_list;



#define lock() lock_get(kill_lock)

#define unlock() lock_release(kill_lock)



/* copy and paste from TM -- might consider putting in better
   in some utils part of core
*/
static void timer_routine(unsigned int ticks , void * attr)
{
   struct timer_link *tl, *tmp_tl, *end, *ret;
   int killr;

   /* check if it worth entering the lock */
   if (kill_list.first_tl.next_tl==&kill_list.last_tl 
         || kill_list.first_tl.next_tl->time_out > ticks )
      return;

   lock();
   end = &kill_list.last_tl;
   tl = kill_list.first_tl.next_tl;
   while( tl!=end && tl->time_out <= ticks ) {
      tl=tl->next_tl;
   }

   /* nothing to delete found */
   if (tl->prev_tl==&kill_list.first_tl) {
      unlock();
      return;
   }
   /* the detached list begins with current beginning */
   ret = kill_list.first_tl.next_tl;
   /* and we mark the end of the split list */
   tl->prev_tl->next_tl = 0;
   /* the shortened list starts from where we suspended */
   kill_list.first_tl.next_tl = tl;
   tl->prev_tl = & kill_list.first_tl;
   unlock();

   /* process the list now */
   while (ret) {
      tmp_tl=ret->next_tl;
      ret->next_tl=ret->prev_tl=0;
      if (ret->time_out>0) {
         killr=kill(ret->pid, SIGTERM );
         LM_DBG("child process (%d) kill status: %d\n", ret->pid, killr );
      }
      shm_free(ret);
      ret=tmp_tl;
   }
}

int schedule_to_kill( int pid )
{
   struct timer_link *tl;
   tl=shm_malloc( sizeof(struct timer_link) );
   if (tl==0) {
      LM_ERR("no shmem\n");
      return -1;
   }
   memset(tl, 0, sizeof(struct timer_link) );
   lock();
   tl->pid=pid;
   tl->time_out=get_ticks()+time_to_kill;
   tl->prev_tl=kill_list.last_tl.prev_tl;
   tl->next_tl=&kill_list.last_tl;
   kill_list.last_tl.prev_tl=tl;
   tl->prev_tl->next_tl=tl;
   unlock();
   return 1;
}

int initialize_kill(void)
{
   /* if disabled ... */
   if (time_to_kill==0) return 1;
    if ((register_timer( timer_routine,
            0 /* param */, 1 /* period */)<0)) {
        LM_ERR("no exec timer registered\n");
        return -1;
    }
   kill_list.first_tl.next_tl=&kill_list.last_tl;
   kill_list.last_tl.prev_tl=&kill_list.first_tl;
   kill_list.first_tl.prev_tl=
   kill_list.last_tl.next_tl = 0;
   kill_list.last_tl.time_out=-1;
   kill_lock=lock_alloc();
   if (kill_lock==0) {
      LM_ERR("no shm mem for mutex\n");
      return -1;
   }
   lock_init(kill_lock);
   LM_DBG("kill initialized\n");
   return 1;
}

void destroy_kill(void)
{
   /* if disabled ... */
   if (time_to_kill==0) 
      return; 
   if (kill_lock) {
      lock_destroy(kill_lock);
      lock_dealloc(kill_lock);
   }
   return;
}