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/* ______ ___ ___
* /\ _ \ /\_ \ /\_ \
* \ \ \L\ \\//\ \ \//\ \ __ __ _ __ ___
* \ \ __ \ \ \ \ \ \ \ /'__`\ /'_ `\/\`'__\/ __`\
* \ \ \/\ \ \_\ \_ \_\ \_/\ __//\ \L\ \ \ \//\ \L\ \
* \ \_\ \_\/\____\/\____\ \____\ \____ \ \_\\ \____/
* \/_/\/_/\/____/\/____/\/____/\/___L\ \/_/ \/___/
* /\____/
* \_/__/
*
* Memory mapping helpers for Linux Allegro.
*
* By George Foot, heavily based upon Marek Habersack's code.
*
* See readme.txt for copyright information.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include "allegro.h"
#include "allegro/internal/aintern.h"
#include "allegro/platform/aintunix.h"
#if !defined(_POSIX_MAPPED_FILES) || !defined(ALLEGRO_HAVE_MMAP)
#error "Sorry, mapped files are required for Linux console Allegro to work!"
#endif
#include <unistd.h>
#include <sys/mman.h>
static int mem_fd = -1; /* fd of /dev/mem */
/* __al_linux_init_memory:
* Prepares to be able to map memory; returns 0 on success.
*/
int __al_linux_init_memory (void)
{
mem_fd = open ("/dev/mem", O_RDWR);
if (mem_fd < 0) return 1;
mprotect ((void *)&mem_fd, sizeof mem_fd, PROT_READ);
return 0;
}
/* __al_linux_shutdown_memory:
* Turns off memory mapping, returning 0 on success.
*/
int __al_linux_shutdown_memory (void)
{
if (mem_fd < 0) return 1;
mprotect ((void *)&mem_fd, sizeof mem_fd, PROT_READ | PROT_WRITE);
close (mem_fd);
mem_fd = -1;
return 0;
}
/* __al_linux_map_memory:
* Given a MAPPED_MEMORY struct with physical address, size and
* permissions filled in, this function maps the memory and fills
* in the pointer in the struct. Returns 0 on success; errno will
* be set on error.
*/
int __al_linux_map_memory (struct MAPPED_MEMORY *info)
{
ASSERT(info);
info->data = mmap (0, info->size, info->perms, MAP_SHARED, mem_fd, info->base);
if (info->data == MAP_FAILED) {
info->data = NULL;
return 1;
}
return 0;
}
/* __al_linux_unmap_memory:
* Given a MAPPED_MEMORY struct, this function unmaps
* the block. Returns 0 on success, errno set on error.
*/
int __al_linux_unmap_memory (struct MAPPED_MEMORY *info)
{
ASSERT(info);
if (info->data == NULL)
return 0;
if (!munmap (info->data, info->size)) {
info->data = NULL;
return 0;
}
return 1;
}
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