shm.c 1.61 KB
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#ifndef LIBRARIES
#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>
#include <stdio.h>
#include <unistd.h>
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#endif

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#include <string.h>
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#include <sys/mman.h>
#include <sys/types.h>
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#define BUFFER_SHM_NAME "/11777707_buff"
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int create_shmfd(char *shm_name) {
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    int shmfd = shm_open(shm_name, O_RDWR | O_CREAT, 0600);
    if(shmfd == -1) {
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        fprintf(stderr, "ERROR: Failed creating shared memory object\n");
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        exit(EXIT_FAILURE);
    }
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    return shmfd;
}
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void truncate_shm(int shmfd, size_t shm_size) {
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    if(ftruncate(shmfd, shm_size) < 0) {
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        fprintf(stderr, "ERROR: Failed truncating shared memory object\n");
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        exit(EXIT_FAILURE);
    }
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}
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void* open_shm(int shmfd, size_t shm_size) {
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    void* shm;
    shm = mmap(NULL, shm_size, PROT_READ | PROT_WRITE, MAP_SHARED, shmfd, 0);

    if(shm == MAP_FAILED) {
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        fprintf(stderr, "ERROR: Failed mapping shared memory object\n");
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        exit(EXIT_FAILURE);
    }

    return shm;
}

void write_to_shm(void* shm, char *message, size_t message_size) {
    memcpy(shm, message, message_size);
}

void close_shm(void* shm, size_t shm_size) {
    if (munmap(shm, shm_size) == -1) {
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        fprintf(stderr, "ERROR: Failed unmapping shared memory object\n");
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        exit(EXIT_FAILURE);
    }
}

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void destroy_shm(char *shm_name, int shmfd) {
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    if (shm_unlink(shm_name) == -1) {
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        fprintf(stderr, "ERROR: Failed unlinking shared memory object\n");
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        exit(EXIT_FAILURE);
    }
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    if(close(shmfd) < 0) {
        fprintf(stderr, "ERROR: Failed closing file descriptor\n");
        exit(EXIT_FAILURE);
    }
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}