thrstartstop.c

linux环境下用纯c写的RTP协议的通用开发库

/*-------------------------------------------------------------------------
 * thrstartstop.c - startthread, stopthread
 *-------------------------------------------------------------------------
 */

#include <pthread.h>
#include <signal.h>
#include <util.h>
#include <time.h>
#include <errno.h>

/*------------------------------------------------------------------------
 * startthread - cleanly start a thread
 *------------------------------------------------------------------------
 */
int
startthread(pthread_t *thread, void *(*fcn)(void *), void *arg, pthread_mutex_t *mutex, pthread_cond_t *cond, int *statusvar)
{

	int rv;
  
	pthread_mutex_lock(mutex);

	if (*statusvar == THR_RUNNING || *statusvar == THR_INITIALIZING) {
		pthread_mutex_unlock(mutex);
		return OK;
	}

	if (*statusvar == THR_TERMINATE) {
		pthread_mutex_unlock(mutex);
		return ERROR;
	}

	*statusvar = THR_INITIALIZING;      
	rv = pthread_create(thread, NULL, fcn, (void *) arg);
	if (rv != 0) {
		*statusvar = THR_NOTRUNNING;
		pthread_mutex_unlock(mutex);
		return ERROR;
	}

	pthread_mutex_unlock(mutex);
	return OK;
}

/*------------------------------------------------------------------------
 * stopthread - cleanly stop a thread; block until thread acknowledges
 *------------------------------------------------------------------------
 */
int
stopthread(pthread_t *thread, pthread_mutex_t *mutex, pthread_cond_t *cond, int *statusvar)
{

	int tries = 0;
	int rv;
	struct timespec time, delta = UTIL_STOPTHREADDELTA;

	pthread_mutex_lock(mutex);
  
	/*
	 * Don't send signal before handler installed.
	 */
	while(*statusvar == THR_INITIALIZING)
		pthread_cond_wait(cond, mutex);
  
	if (*statusvar != THR_RUNNING) {
		pthread_mutex_unlock(mutex);
		return OK;
	}
  
	*statusvar = THR_TERMINATE;
  
	/* 
	 * Try UTIL_STOPTHREADMAXTRIES sending the SIGTERM
	 * signal and waiting for an acknowledgement
	 * before returning an error.
	 */
	while(*statusvar != THR_NOTRUNNING) {
		if (tries++ == UTIL_STOPTHREADMAXTRIES) {
			*statusvar = THR_RUNNING;
			pthread_mutex_unlock(mutex);
			return ERROR;
		}
		clock_gettime(CLOCK_REALTIME, &time);
		time = timeadd(time, delta);
		pthread_kill(*thread, SIGTERM);
		rv = pthread_cond_timedwait(cond, mutex, &time);
		if (rv != 0 && rv != ETIMEDOUT) {
			*statusvar = THR_RUNNING;
			pthread_mutex_unlock(mutex);
			return ERROR;
		}
	}
  
	*thread = 0;
	pthread_mutex_unlock(mutex);
	return OK;
}