Enrico Fraccaroli (Galfurian)
98 lines
2.2 KiB
C
98 lines
2.2 KiB
C
//test
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#include "sys/sem.h"
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#include "stdio.h"
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#include "sys/ipc.h"
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#include "sys/errno.h"
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#include "sys/wait.h"
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#include "stdlib.h"
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#include "sys/unistd.h"
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#include "fcntl.h"
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/*
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First test of System V Semaphores.
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Correct output should be: Corso di Sistemi Operativi.
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*/
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void semid_print(struct semid_ds *temp)
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{
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printf("pid, IPC_KEY, Semid, semop, change: %d, %d, %d, %d, %d\n", temp->sem_perm.uid, temp->sem_perm.key, temp->semid, temp->sem_otime, temp->sem_ctime);
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for (int i = 0; i < (temp->sem_nsems); i++) {
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printf("%d semaphore:\n", i + 1);
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printf("value: %d, pid %d, process waiting %d\n", temp->sems[i].sem_val, temp->sems[i].sem_pid, temp->sems[i].sem_zcnt);
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}
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}
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int main()
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{
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struct sembuf sops[6];
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sops[0].sem_num = 0;
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sops[0].sem_op = -1;
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sops[0].sem_flg = 0;
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sops[1].sem_num = 1;
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sops[1].sem_op = -1;
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sops[1].sem_flg = 0;
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sops[2].sem_num = 2;
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sops[2].sem_op = -1;
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sops[2].sem_flg = 0;
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sops[3].sem_num = 0;
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sops[3].sem_op = 1;
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sops[3].sem_flg = 0;
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sops[4].sem_num = 1;
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sops[4].sem_op = 1;
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sops[4].sem_flg = 0;
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sops[5].sem_num = 2;
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sops[5].sem_op = 1;
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sops[5].sem_flg = 0;
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int status;
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//create a semaphore set
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int semid = semget(IPC_PRIVATE, 4, IPC_CREAT | IPC_EXCL | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
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//set the values of the semaphores
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unsigned short values[] = { 0, 0, 0, 1 };
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union semun arg;
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arg.array = values;
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if (semctl(semid, 0, SETALL, &arg) == -1) {
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perror("Failed to set semaphores");
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return 1;
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}
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if (!fork()) {
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semop(semid, &sops[0], 1);
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printf("cheers!\n");
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exit(0);
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}
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if (!fork()) {
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semop(semid, &sops[1], 1);
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printf("course, ");
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semop(semid, &sops[3], 1);
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exit(0);
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}
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if (!fork()) {
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semop(semid, &sops[2], 1);
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printf("systems ");
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semop(semid, &sops[4], 1);
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exit(0);
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}
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if (!fork()) {
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printf("From the operating ");
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semop(semid, &sops[5], 1);
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exit(0);
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}
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for (int n = 0; n < 4; n++) {
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wait(&status);
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}
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if (semctl(semid, 0, IPC_RMID, 0) == -1) {
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perror("Failed to remove IPC");
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return 1;
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}
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return 0;
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} |