ipcsem.c

本文件介绍了unix内核的c源代码

#include <sys/sem.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <stdio.h>
#include <sys/stat.h>

#define VERIFYERR(a, b)  \
	if (a) fprintf(stderr, "%s failed.\n", b);  \
	else fprintf(stderr, "%s success.\n", b);  

void main(int argc, char *argv[])
{
	int semid, index, i;
	struct semid_ds ds;	
	unsigned short array[100];
	if (argc != 4) return;
	semid = atoi(argv[1]);
	index = atoi(argv[2]);

	if (argv[3][0] == 'c')
	{	/* 创建信号量 */
		VERIFYERR(semget(semid, index, 0666|IPC_CREAT|IPC_EXCL) < 0, "Create sem");
	}
	else if (argv[3][0] == 'd')
	{	/* 删除消息队列 */
		VERIFYERR(semctl(semid, 0, IPC_RMID, NULL) < 0, "Delete sem");

	}	
	else if (argv[3][0] == 'v')
	{	/* 查看信号量信息 */
		fprintf(stderr, "T     ID      INDEX       SEMVAL  SEMPID      SEMNCNT    SEMZCNT\n");
		fprintf(stderr, "s %6d %6d %10d %10d %10d %10d\n",
			semid, 					/* 标识号 */
			index,					/* 信号量序号 */
			semctl(semid, index, GETVAL), 		/* 信号量值 */
			semctl(semid, index, GETPID), 		/* 最近访问进程ID */
			semctl(semid, index, GETNCNT), 		/* P阻塞进程数 */
			semctl(semid, index, GETZCNT));		/* Z阻塞进程数 */
	}
	else if (argv[3][0] == 'a')
	{	/* 查看信号量信息 */
		ds.sem_nsems = 0;
		VERIFYERR(semctl(semid, 0, IPC_STAT, &ds) != 0, "Get Sem Stat");
		VERIFYERR(semctl(semid, 0, GETALL, array)!= 0, "Get Sem All");
		for (i=0; i<ds.sem_nsems; i++)
		{
			fprintf(stderr, "sem no[%d]  [%d]\n", i, array[i]);
		}
	}
	else 
	{
		VERIFYERR(semctl(semid, index, SETVAL, atoi(argv[3])) != 0, "Set Sem Val");
	}		
}