/* 
  * $Id$
  * 
  * Copyright (C) 2009 iptelorg GmbH
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 /*
  * timer_proc.c  - separate process timers
  * (unrelated to the main fast and slow timers)
  */
 /*
  * History:
  * --------
  *  2009-03-10  initial version (andrei)
 */
 
 #include "timer_proc.h"
 #include "pt.h"
 #include "mem/shm_mem.h"
 
 #include <unistd.h>
 
 
 /** forks a separate simple sleep() periodic timer.
   * Forks a very basic periodic timer process, that just sleep()s for 
   * the specified interval and then calls the timer function.
   * The new "dummy timer" process execution start immediately, the sleep()
   * is called first (so the first call to the timer function will happen
   * <interval> seconds after the call to fork_dummy_timer)
   * @param child_id - @see fork_process()
   * @param desc     - @see fork_process()
   * @param make_sock - @see fork_process()
   * @param f         - timer function/callback
   * @param param     - parameter passed to the timer function
   * @param interval  - interval in seconds.
   * @return - pid of the new process on success, -1 on error
   *           (doesn't return anything in the child process)
   */
 int fork_dummy_timer(int child_id, char* desc, int make_sock,
 						timer_function* f, void* param, int interval)
 {
 	int pid;
 	
 	pid=fork_process(child_id, desc, make_sock);
 	if (pid<0) return -1;
 	if (pid==0){
 		/* child */
 		for(;;){
 			sleep(interval);
 			f(get_ticks(), param); /* ticks in s for compatibility with old
 									  timers */
 		}
 	}
 	/* parent */
 	return pid;
 }
 
 
 
 /** forks a timer process based on the local timer.
  *  Forks a separate timer process running a local_timer.h type of timer
  *  A pointer to the local_timer handle (allocated in shared memory) is
  *  returned in lt_h. It can be used to add/delete more timers at runtime
  *  (via local_timer_add()/local_timer_del() a.s.o).
  *  If timers are added from separate processes, some form of locking must be
  *  used (all the calls to local_timer* must be enclosed by locks if it
  *  cannot be guaranteed that they cannot execute in the same time)
  *  The timer "engine" must be run manually from the child process. For
  *  example a very simple local timer process that just runs a single 
  *  periodic timer can be started in the following way:
  *      struct local_timer* lt_h;
  *
  *      pid=fork_local_timer_process(...., &lt_h);
  *      if (pid==0){
  *          timer_init(&my_timer, my_timer_f, 0, 0);
  *          local_timer_add(&lt_h, &my_timer, S_TO_TICKS(10), get_ticks_raw());
  *          while(1) { sleep(1); local_timer_run(lt, get_ticks_raw()); }
  *      }
  *
  * @param child_id - @see fork_process()
  * @param desc     - @see fork_process()
  * @param make_sock - @see fork_process()
  * @param lt_h      - local_timer handler
  * @return - pid to the parent, 0 to the child, -1 if error.
  */
 int fork_local_timer_process(int child_id, char* desc, int make_sock,
 						struct local_timer** lt_h)
 {
 	int pid;
 	struct local_timer* lt;
 	
 	lt=shm_malloc(sizeof(*lt));
 	if (lt==0) goto error;
 	if (init_local_timer(lt, get_ticks_raw())<0) goto error;
 	pid=fork_process(child_id, desc, make_sock);
 	if (pid<0) goto error;
 	*lt_h=lt;
 	return pid;
 error:
 	if (lt) shm_free(lt);
 	return -1;
 }
 
 
 /* vi: set ts=4 sw=4 tw=79:ai:cindent: */