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change to semaphores #7

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56 changes: 51 additions & 5 deletions OS-Scheduler/OS-Scheduler/process.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2,9 +2,53 @@

/* Modify this file as needed*/
int remainingtime;
union Semun
{
int val; /* Value for SETVAL */
struct semid_ds *buf; /* Buffer for IPC_STAT, IPC_SET */
unsigned short *array; /* Array for GETALL, SETALL */
struct seminfo *__buf; /* Buffer for IPC_INFO (Linux-specific) */
};

void down(int sem)
{
struct sembuf op;

op.sem_num = 0;
op.sem_op = -1;
op.sem_flg = !IPC_NOWAIT;

if (semop(sem, &op, 1) == -1)
{
perror("Error in down()");
exit(-1);
}
}

void up(int sem)
{
struct sembuf op;

op.sem_num = 0;
op.sem_op = 1;
op.sem_flg = !IPC_NOWAIT;

if (semop(sem, &op, 1) == -1)
{
perror("Error in up()");
exit(-1);
}
}
int main(int agrc, char *argv[])
{
int sem1 = semget('5', 1, 0666 | IPC_CREAT);
int sem2 = semget('6', 1, 0666 | IPC_CREAT);

if (sem1 == -1 || sem2 == -1)
{
perror("Error in create sem");
exit(-1);
}
initClk();
key_t key = ftok("key", 'r'); // shared memory to get the remain time of the running process
int runPshmid = shmget(key, 4, 0666 | IPC_CREAT);
Expand All @@ -30,14 +74,16 @@ int main(int agrc, char *argv[])
while (currentTime == getClk()) // wait till the next clk;
if (remainingTime == 0)
break;

down(sem2);
(*runPshmadd)--;
remainingTime = (*runPshmadd);
up(sem1);
printf("process%d:%d\n",getpid(), currentTime);
// printf("%d",getpid());
kill(getppid(),SIGCONT);
raise(SIGSTOP);
usleep(100); //wait 10microseconds
kill(getppid(),SIGCONT);
// kill(getppid(),SIGCONT);
// raise(SIGSTOP);
// usleep(100); //wait 10microseconds
// kill(getppid(),SIGCONT);
currentTime = getClk(); // update the time
}

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