fpm_shm.c

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    /* (c) 2007,2008 Andrei Nigmatulin, Jerome Loyet */
 
#include <sys/mman.h>
#include <errno.h>
#include <string.h>
 
#include "fpm_shm.h"
#include "zlog.h"
 
 
/* MAP_ANON is deprecated, but not in macOS */
#if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
#define MAP_ANONYMOUS MAP_ANON
#endif
 
static size_t fpm_shm_size = 0;
 
void *fpm_shm_alloc(size_t size) /* {{{ */
{
    void *mem;
 
    mem = mmap(0, size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0);
 
#ifdef MAP_FAILED
    if (mem == MAP_FAILED) {
        zlog(ZLOG_SYSERROR, "unable to allocate %zu bytes in shared memory: %s", size, strerror(errno));
        return NULL;
    }
#endif
 
    if (!mem) {
        zlog(ZLOG_SYSERROR, "unable to allocate %zu bytes in shared memory", size);
        return NULL;
    }
 
    fpm_shm_size += size;
    return mem;
}
/* }}} */
 
int fpm_shm_free(void *mem, size_t size) /* {{{ */
{
    if (!mem) {
        zlog(ZLOG_ERROR, "mem is NULL");
        return 0;
    }
 
    if (munmap(mem, size) == -1) {
        zlog(ZLOG_SYSERROR, "Unable to free shm");
        return 0;
    }
 
    if (fpm_shm_size > size) {
        fpm_shm_size -= size;
    } else {
        fpm_shm_size = 0;
    }
 
    return 1;
}
/* }}} */
 
size_t fpm_shm_get_size_allocated(void)
{
    return fpm_shm_size;
}