int main(int argc, const char * argv[]) {
int key; //unique integer identifier for the shared memory region to be created, attached to, or
//detached from
void *address; //pointer to the lowest (virtual) address in the shared memory region
sem_t semID; //semaphore ID
int err; //error code from a system call
int i; //used for a counter
key = 12345;
//create a two-page shared region (each page is 4K bytes)
err = shmem(key,2, (void **) &address);
if (err != 0) {
printf("shmem failed in shmdemo 1; error code = %d\n", err);
exit(1);
}
//fill all except first 4 bytes with random ints (each int is 4 bytes long)
//--original number is 2048 because each page is 1024 and there are 2 pages--
for(i=1;i<=2047;i++)
{
address[i] = rand();
}
//create semophore with initial count of 0
semID = newsema(0);
if (semID < 0)
{
printf("newsema failed; error code = %d\n", (int)semID);
shmem(key,0,(void **)&address); /* free the shared memory */
exit(1);
}
//put semID in the first 4 bytes of shared memory region
address[0] = int(semID);
printf("\nWaiting on the second process....\n");
//do a down operation on a semaphore (5 min)
//if time runs out, throw an error
if(down(semID,300000) == TIMEOUT)
{
printf("shmdemo 1 timed out.\n");
}
else
{
printf("Successfully returned to shmdemo 1.\n");
}
shmem(key,0,(void **)&address);
freesema(semID);
return 0;
}
/*
* This is called to free all the memory associated with a dquot
*/
void
xfs_qm_dqdestroy(
xfs_dquot_t *dqp)
{
ASSERT(! XFS_DQ_IS_ON_FREELIST(dqp));
mutex_destroy(&dqp->q_qlock);
freesema(&dqp->q_flock);
sv_destroy(&dqp->q_pinwait);
#ifdef XFS_DQUOT_TRACE
if (dqp->q_trace)
ktrace_free(dqp->q_trace);
dqp->q_trace = NULL;
#endif
kmem_zone_free(xfs_Gqm->qm_dqzone, dqp);
atomic_dec(&xfs_Gqm->qm_totaldquots);
}
int main(int argc, char *argv[])
{
int which; /* which way was the program invoked? */
int err; /* error code from a system call */
int *mem; /* pointer to the shared memory region */
int i; /* loop index */
sem_t s; /* semaphore ID */
if (argc == 2)
which = atoi(argv[1]);
if (argc != 2 || which < 1 || which > 2) {
printf("Usage: shmdemo 1 -or- shmdemo 2\n");
printf("Look at the program source code for details on operation.\n");
return 1;
}
if (which == 1) {
err = shmem(12345,1,(void **)&mem);
if (err != 0) {
printf("shmem failed in shmdemo 1; error code = %d\n", err);
exit(1);
}
s = newsema(0);
if (s < 0) {
printf("newsema failed; error code = %d\n", (int)s);
shmem(12345,0,(void **)&mem); /* free the shared memory */
exit(1);
}
mem[0] = (int)s;
for(i=1; i<=100; i++)
mem[i] = i;
if (down(s,60 * 1000) == TIMEOUT) /* one minute, for now XXX */
printf("shmdemo 1 timed out.\n");
else
printf("Successfully returned to shmdemo 1.\n");
shmem(12345,0,(void **)&mem);
freesema(s);
return 0;
}
if (which == 2) {
err = shmem(12345,1,(void **)&mem);
if (err != 0) {
printf("shmem failed in shmdemo 2; error code = %d\n", err);
exit(1);
}
err = 0; /* this is 0 anyway, but we'll be explicit */
for(i=1; i<=100; i++) {
if (mem[i] != i) {
err = i;
break;
}
}
if (err) {
printf("shmdemo 2 error: value in mem[%d] = %d.\n", err, mem[err]);
printf(" It should be %d\n", err);
} else
printf("shmdemo 2: all integer values are as expected.\n");
s = (sem_t)mem[0];
shmem(12345,0,(void **)&mem);
up(s);
return 0;
}
}
