/*********************/
/* semaphore manager */
/*********************/
#include <errno.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
extern int errno;
int main(int argc, char *argv[])
{
    int id, i, uid, gid, isDelete=0;
    char c;
    struct semid_ds mysemds;
    union semun arg;
    /* point to allocated space first */
    arg.buf = &mysemds;
    /* get args */
    while((c=getopt(argc, argv,"hd"))!=(char)(-1))
        switch(c)
        {
        case 'h':
            printf("Version: 1.11, Author: Liao Dongyi(liaody@mit.edu)\n"
                   "  Check and manipulate shared memory blocks\n"
                   "Usage: %s -hd\n"
                   "-h\tThis message\n"
                   "-d\tDelete every found shared memory if possible\n"
                   ,argv[0]);
            exit(0);
        case 'd':
            isDelete=1;
            break;
        case 'c':;
        }
    /* initialize, getuid, etc.. */
    printf("User ID=%d, Group ID=%d\n",uid=getuid(), gid=getgid());
    /* try the semctl(IPC_STAT) to look at all the semaphores */
    printf("Looking for semaphore id=0--65535...\n");
    for (i=0; i<65536; i++)
	if (semctl(i,0,IPC_STAT,arg)!=-1)
        {
            printf("  semctl successed on id=%d.\n", i);
            printf("    # of elements : %d\n",arg.buf->sem_nsems);
            printf("    last change time : %s",ctime(&(arg.buf->sem_ctime)));
#ifdef _SYS_IPC_BUF_H /* RedHat Linux 5.2: see /usr/include/sys/ipc_buf.h */
	    printf("    Key  : %d\n", arg.buf->sem_perm.__key);
#else
	    printf("    Key  : %d\n", arg.buf->sem_perm.key);
#endif
	    printf("    UGID : %d,%d(%s)\n",arg.buf->sem_perm.uid,
		   arg.buf->sem_perm.gid,
                   (uid==arg.buf->sem_perm.uid && gid==arg.buf->sem_perm.gid)?
                   "own":"not own");
            if (isDelete)
                if(semctl(i,0,IPC_RMID,NULL)==-1)
                    printf("    - Fail to remove\n");
                else printf("    - Success to remove\n");
        }
        else if(errno != EINVAL && errno != EIDRM)
        {
            printf ("  semctl failed on id=%d (%s).\n", i,
                    strerror(errno)) ;
            if (isDelete)
                if(semctl(i,0,IPC_RMID,NULL)==-1)
                    printf("    - Fail to remove\n");
                else printf("    - Success to remove\n");
        }
    return(0);
} /* end main() */