l3.libnazgul/src/queueInit.c

#include "libnazgul.h"
#include "ids.h"

msgQueue *msgQueueInit(msgSpaceId externId, int queueIdx)
{
	int queueFd;
	msgQueue *queue;
	sem_t *semProtectFd;
	msgQueueSemId queueSemProtectId;
	sem_t *semReadableFd;
	msgQueueSemId queueSemReadableId;
	msgQueueId queueId;

	queue = NULL;

	msgQueueProtSemIdIntern(queueSemProtectId, externId, queueIdx);
	msgQueueReadSemIdIntern(queueSemReadableId, externId, queueIdx);

	// creation du semaphore de lecture 
	semReadableFd = sem_open(queueSemReadableId,
				 O_CREAT | O_EXCL, SEM_DEFAULT_MODE, 0);
	if (semReadableFd == SEM_FAILED) {
		NZG_ERROR("sem_open", queueSemReadableId);
		goto ERROR;
	}
	// creation du semaphore de protection
	semProtectFd = sem_open(queueSemProtectId,
				O_CREAT | O_EXCL, SEM_DEFAULT_MODE, 0);
	if (semProtectFd == SEM_FAILED) {
		NZG_ERROR("sem_open", queueSemProtectId);
		goto ERROR;
	}

/*	if(sem_wait(semProtectFd)==-1){
	  NZG_ERROR("sem_wait",queueSemProtectId);
	  goto ERROR;
	} */

	if (msgQueueIdIntern(queueId, externId, queueIdx) < 0) {
		return NULL;
	}

	queueFd =
	    shm_open(queueId, O_RDWR | O_CREAT | O_EXCL | O_TRUNC,
		     MSGSPACE_DEFAULT_MODE);
	if (queueFd == -1) {
		NZG_ERROR("shm_open : queueInit", queueId);
		return NULL;
	}

	if (ftruncate(queueFd, sizeof(msgQueue)) == -1) {
		fprintf(stderr, "Queue resizing failed: %s\n", strerror(errno));
		return NULL;
	}

	queue = msgQueueOpen(queueId);
	/* on remplit la structure msgQueue */
	queue->elemCounter = 0;
	strcpy(queue->id, queueId);
	strcpy(queue->headId, queue->id);
	strcpy(queue->tailId, queue->id);

	/* on ferme tout ce qu'il faut */
	close(queueFd);
	msgQueueProtUnlock(externId, queueIdx);

	return queue;
 ERROR:
	return NULL;

}