sem.c

Go to the documentation of this file.

 
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
 
#include <errno.h>
#include <string.h>
 
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/stat.h>
#include <sys/types.h>
 
#include "log.h"
#include "rl.h"
 
#include "sem.h"
 
int sem_create(key_t key, int count) {
    int id = semget(key, count, IPC_CREAT | S_IRWXU);
    if (id < 0) {
        rl_log(RL_LOG_ERROR, "Failed to create semaphore; %d message: %s",
               errno, strerror(errno));
    }
    return id;
}
 
int sem_remove(int id) {
    int ret = semctl(id, 0, IPC_RMID);
    if (ret < 0) {
        rl_log(RL_LOG_ERROR, "Failed to remove semaphore; %d message: %s",
               errno, strerror(errno));
        return ret;
    }
    return SUCCESS;
}
 
int sem_open(key_t key, int count) {
    int id = semget(key, count, S_IRWXU);
    if (id < 0) {
        rl_log(RL_LOG_ERROR, "Failed to open semaphore; %d message: %s", errno,
               strerror(errno));
        return id;
    }
    return id;
}
 
int sem_wait(int id, int index, int timeout) {
    int num_ops = 1;
    int sem_op = -1;
    struct sembuf sem_ops = {index, sem_op, SEM_OPT_NO_FLAG};
    struct timespec timeout_struct = {timeout, 0};
 
    int ret = semtimedop(id, &sem_ops, num_ops, &timeout_struct);
    if (ret < 0) {
        if (errno == EAGAIN) {
            rl_log(RL_LOG_ERROR, "Timeout waiting on semaphore; %d message: %s",
                   errno, strerror(errno));
        } else if (errno == EIDRM) {
            rl_log(RL_LOG_ERROR,
                   "Failed waiting on semaphore, semaphore removed; %d "
                   "message: %s",
                   errno, strerror(errno));
        } else if (errno == EINVAL) {
            rl_log(RL_LOG_ERROR,
                   "Failed waiting on semaphore, semaphore inexistent; %d "
                   "message %s",
                   errno, strerror(errno));
        } else {
            rl_log(RL_LOG_ERROR, "Failed waiting on semaphore; %d message: %s",
                   errno, strerror(errno));
        }
        return ret;
    }
    return SUCCESS;
}
 
int sem_set(int id, int index, int value) {
    int num_ops = 1;
    struct sembuf sem_ops = {index, value, SEM_OPT_NO_FLAG};
    struct timespec timeout_struct = {SEM_TIMEOUT_WRITE, 0};
 
    int ret = semtimedop(id, &sem_ops, num_ops, &timeout_struct);
    if (ret < 0) {
        if (errno == EAGAIN) {
            rl_log(RL_LOG_ERROR,
                   "Timeout on setting semaphore count; %d message: %s", errno,
                   strerror(errno));
        } else {
            rl_log(RL_LOG_ERROR,
                   "Failed setting semaphore count; %d message: %s", errno,
                   strerror(errno));
        }
        return ret;
    }
    return SUCCESS;
}
 
int sem_get(int id, int index) {
    int count = semctl(id, index, GETNCNT);
    if (count < 0) {
        rl_log(RL_LOG_ERROR, "Failed getting semaphore count; %d message: %s",
               errno, strerror(errno));
        return count;
    }
    return count;
}