121 lines
3.7 KiB
C
121 lines
3.7 KiB
C
#ifndef LIBRARIES
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#define LIBRARIES
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#define _GNU_SOURCE
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#include <fcntl.h> ///< For O_* constants *
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#endif
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#include <errno.h>
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#include <semaphore.h> ///< For semaphores
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#define FREE_SEM_NAME "/11777707_free"
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#define USE_SEM_NAME "/11777707_used"
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#define MUTEX_NAME "/11777707_mutex"
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static sem_t *free_sem;
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static sem_t *use_sem;
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static sem_t *mutex;
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/**
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* @brief Function that executes sem_open(3) and does error handling.
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* @details The function executes sem_open(3), giving it a semaphor name and size as parameters,
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* and handles the errors if any. The same behaviour as sem_open(3) should be expected.
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* The type parameter is used to determine how the semaphore should be opened:
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* - as a supervisor: 0
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* - as a generator: 1
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* Returns a new semaphore
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* @param sem_name, sem_size, type
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* @return res
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**/
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sem_t * open_sem(char *sem_name, size_t sem_size, short type) {
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sem_t *res;
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if(type == 0)
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res = sem_open(sem_name, O_CREAT | O_EXCL, 0600, sem_size);
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else
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res = sem_open(sem_name, sem_size);
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if(res == SEM_FAILED) {
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fprintf(stderr, "ERROR: Failed opening semaphore\n");
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exit(EXIT_FAILURE);
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}
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return res;
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}
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/**
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* @brief Function that executes sem_getvalue(3) and does error handling.
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* @details The function executes sem_getvalue(3), giving it a semaphor and size as parameters,
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* and handles the errors if any. The same behaviour as sem_getvalue(3) should be expected.
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* Writes the value of a semaphore to a chosen pointer
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* @param sem, rem
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* @return none
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**/
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void getval_sem(sem_t *sem, int *res) {
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if(sem_getvalue(sem, res) == -1) {
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fprintf(stderr, "ERROR: Failed getting semaphore value\n");
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exit(EXIT_FAILURE);
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}
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}
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/**
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* @brief Function that executes sem_wait(3) and does error handling.
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* @details The function executes sem_wait(3), giving it a semaphor as a parameter,
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* and handles the errors if any. The same behaviour as sem_wait(3) should be expected.
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* If the process was terminated, the function exits
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* @param sem
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* @return none
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**/
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void wait_sem(sem_t *sem) {
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if(sem_wait(sem) == -1) {
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if(errno == EINTR) {
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return;
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}
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fprintf(stderr, "ERROR: Failed locking semaphore\n");
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exit(EXIT_FAILURE);
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}
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}
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/**
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* @brief Function that executes sem_post(3) and does error handling.
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* @details The function executes sem_post(3), giving it a semaphor as a parameter,
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* and handles the errors if any. The same behaviour as sem_post(3) should be expected.
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* @param sem
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* @return none
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**/
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void post_sem(sem_t *sem) {
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if(sem_post(sem) == -1) {
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fprintf(stderr, "ERROR: Failed unlocking semaphore\n");
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exit(EXIT_FAILURE);
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}
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}
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/**
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* @brief Function that executes sem_close(3) and does error handling.
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* @details The function executes sem_close(3), giving it a semaphor as a parameter,
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* and handles the errors if any. The same behaviour as sem_close(3) should be expected.
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* @param sem
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* @return none
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**/
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void close_sem(sem_t *sem) {
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if(sem_close(sem) < 0) {
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fprintf(stderr, "ERROR: Failed closing semaphore\n");
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exit(EXIT_FAILURE);
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}
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}
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/**
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* @brief Function that executes sem_unlink(3) and does error handling.
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* @details The function executes sem_unlink(3), giving it a semaphor name as a parameter,
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* and handles the errors if any. The same behaviour as sem_unlink(3) should be expected.
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* @param sem_name
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* @return none
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**/
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void destroy_sem(char *sem_name) {
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if(sem_unlink(sem_name) < 0) {
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fprintf(stderr, "ERROR: Failed closing semaphore\n");
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exit(EXIT_FAILURE);
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}
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}
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