Enrico Fraccaroli (Galfurian)
89 lines
1.9 KiB
C
89 lines
1.9 KiB
C
/// @file t_semop.c
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/// @brief Tests semop between processes.
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/// @copyright (c) 2014-2023 This file is distributed under the MIT License.
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/// See LICENSE.md for details.
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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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int main(int argc, char *argv[])
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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(17, 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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}
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