/*************************/
/* shared memory manager */
/*************************/
#include <errno.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
extern int errno;
int main(int argc, char *argv[])
{
    int id ;
    int i;
    struct shmid_ds buf;
    char c;
    int uid, gid;
    int isDelete=0;
    /* 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 shmctl(IPC_STAT) to look at all the shared memory */
    printf("Looking for shared-memory id=0--65535...\n");
    for(i=0; i<65536; i++)
        if (shmctl(i,IPC_STAT,&buf)!=-1)
        {
            printf("  shmctl successed on id=%d.\n", i);
            printf("    Size : %d\n",buf.shm_segsz);
            printf("    Time : %s",ctime(&buf.shm_atime));
#ifdef _SYS_IPC_BUF_H /* RedHat Linux 5.2: see /usr/include/sys/ipc_buf.h */
	    printf("    Key  : %d\n", buf.shm_perm.__key);
#else
	    printf("    Key  : %d\n", buf.shm_perm.key);
#endif
	    printf("    UGID : %d,%d(%s)\n",buf.shm_perm.uid,buf.shm_perm.gid,
		   (uid==buf.shm_perm.uid && gid==buf.shm_perm.gid)?
		   "own":"not own");
	    if (isDelete)
                if (shmctl(i,IPC_RMID,NULL)==-1)
                    printf("    - Fail to remove\n");
                else printf("    - Success to remove\n");
        }
        else if (errno != EINVAL && errno != EIDRM)
        {
            printf ("  shmctl failed on id=%d (%s).\n", i,
                    strerror(errno)) ;
            if (isDelete)
                if (shmctl(i,IPC_RMID,NULL)==-1)
                    printf("    - Fail to remove\n");
                else printf("    - Success to remove\n");
        }
    return(1);
} /* end main() */