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/*******************************************************************
* File: omMmap.c
* Purpose: implementing valloc via mmap
* Author: obachman (Olaf Bachmann)
* Created: 11/99
*******************************************************************/
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
#define MAP_ANONYMOUS MAP_ANON
#endif
static void* omVallocMmap(size_t size)
{
void* addr;
#ifndef MAP_ANONYMOUS
static int fd = -1;
#endif
#ifdef MAP_ANONYMOUS
#ifndef __CYGWIN__
/* under cygwin, MAP_PRIVATE|MAP_ANONYMOUS fails */
addr = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
#else
/* however, the following works */
addr = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, -1, 0);
#endif
#else /* !MAP_ANONYMOUS */
if (fd < 0)
{
fd = open("/dev/zero", O_RDWR);
if (fd < 0) return NULL;
}
addr = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
#endif
if (addr == (void*) -1) return NULL;
return addr;
}
static int omVfreeMmap(void* addr, size_t size)
{
return munmap(addr, size);
}
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