Aldegheri Alessandro
89 lines
2.3 KiB
C
89 lines
2.3 KiB
C
//test
|
|
#include "ipc/sem.h"
|
|
#include "stdio.h"
|
|
#include "ipc/ipc.h"
|
|
#include "sys/errno.h"
|
|
#include "stdlib.h"
|
|
#include "sys/unistd.h"
|
|
|
|
|
|
/*
|
|
Testing Semaphores.
|
|
This program creates a son and then performs a blocking operation on a semaphore. The son sleeps for
|
|
five seconds and then it wakes up his father and then it deletes the semaphore.
|
|
|
|
*/
|
|
|
|
|
|
void semid_print(struct semid_ds *temp){
|
|
printf("pid, IPC_KEY, Semid, semop, change: %d, %d, %d, %d, %d\n", temp->owner, temp->key, temp->semid, temp->sem_otime, temp->sem_ctime);
|
|
for(int i=0; i<(temp->sem_nsems); i++){
|
|
printf("%d semaphore:\n", i+1);
|
|
printf("value: %d, pid %d, process waiting %d\n", temp->sems[i].sem_val, temp->sems[i].sem_pid, temp->sems[i].sem_zcnt);
|
|
}
|
|
}
|
|
|
|
int main()
|
|
{
|
|
union semun arg;
|
|
arg.val = 1;
|
|
//key_t i = ftok("/test1.txt", 5); //checking ftok
|
|
long id = semget(2,1,IPC_CREAT); //first semaphores
|
|
//long id2 = semget(IPC_PRIVATE, 1, IPC_CREAT);
|
|
//long id2 = semget(2, 2, IPC_EXCL); //need to return -1 bc already exists
|
|
|
|
//long id3 = semget(2, 2, 0); //need to return 3 (semid of the first)
|
|
|
|
//long id4 = semget(100, 2, IPC_CREAT | IPC_EXCL); //need to return 101 (new semaphore)
|
|
long value;
|
|
printf("ID: %d\n", id);
|
|
if ((value = semctl(id, 0, SETVAL, &arg)) == -1){
|
|
printf("ERRORE\n");
|
|
}else{
|
|
//semid_print(arg.v);
|
|
printf("valore sem 0: %d \n", semctl(id, 0, GETVAL, &arg));
|
|
}
|
|
|
|
|
|
|
|
if (!fork()){
|
|
sleep(5);
|
|
struct sembuf op2;
|
|
op2.sem_num = 0;
|
|
op2.sem_op = 150;
|
|
op2.sem_flg = 0;
|
|
semop(id, &op2, 1);
|
|
|
|
semctl(id, 0, IPC_RMID, NULL);
|
|
|
|
exit(0);
|
|
}
|
|
|
|
struct sembuf op;
|
|
op.sem_num = 0;
|
|
op.sem_op = -1;
|
|
op.sem_flg = 0;
|
|
if (semop(id, &op, 2) < 0){
|
|
printf("ERRORE\n");
|
|
}
|
|
printf("valore sem 0: %d \n", semctl(id, 0, GETVAL, &arg));
|
|
|
|
|
|
/*if ((semid = semctl(id, 0, IPC_RMID, 0)) == -1){
|
|
printf("%d\n", errno);
|
|
}else{
|
|
printf("found %d\n", semid);
|
|
}*/
|
|
|
|
|
|
//long id2 = semget(IPC_PRIVATE, 2, 0);
|
|
//long id3 = semget(IPC_PRIVATE, 2, 0);
|
|
//printf("id %d id2 %d id3 %d id4 %d\n", id, id2, id3, id4);
|
|
/*if (i == -1){
|
|
printf("Error with IPC_KEY\n");
|
|
return -1;
|
|
}*/
|
|
|
|
|
|
return 0;
|
|
} |