mirror of
https://github.com/mpv-player/mpv
synced 2024-12-27 09:32:40 +00:00
6e9cbdc104
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@29305 b3059339-0415-0410-9bf9-f77b7e298cf2
83 lines
2.7 KiB
C
83 lines
2.7 KiB
C
/*
|
|
* This file is part of MPlayer.
|
|
*
|
|
* MPlayer is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* MPlayer is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along
|
|
* with MPlayer; if not, write to the Free Software Foundation, Inc.,
|
|
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*/
|
|
|
|
/**
|
|
* \file mmap_anon.c
|
|
* \brief Provide a compatible anonymous space mapping function
|
|
*/
|
|
#include "config.h"
|
|
|
|
#include <stdio.h>
|
|
#include <unistd.h>
|
|
#include <fcntl.h>
|
|
#include <sys/mman.h>
|
|
|
|
#if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
|
|
#define MAP_ANONYMOUS MAP_ANON
|
|
#endif
|
|
|
|
/*
|
|
* mmap() anonymous space, depending on the system's mmap() style. On systems
|
|
* that use the /dev/zero mapping idiom, zerofd will be set to the file descriptor
|
|
* of the opened /dev/zero.
|
|
*/
|
|
|
|
/**
|
|
* \brief mmap() anonymous space, depending on the system's mmap() style. On systems
|
|
* that use the /dev/zero mapping idiom, zerofd will be set to the file descriptor
|
|
* of the opened /dev/zero.
|
|
*
|
|
* \param addr address to map at.
|
|
* \param len number of bytes from addr to be mapped.
|
|
* \param prot protections (region accessibility).
|
|
* \param flags specifies the type of the mapped object.
|
|
* \param offset start mapping at byte offset.
|
|
* \param zerofd
|
|
* \return a pointer to the mapped region upon successful completion, -1 otherwise.
|
|
*/
|
|
void *mmap_anon(void *addr, size_t len, int prot, int flags, off_t offset)
|
|
{
|
|
void *result;
|
|
|
|
/* From loader/ext.c:
|
|
* "Linux EINVAL's on us if we don't pass MAP_PRIVATE to an anon mmap"
|
|
* Therefore we preserve the same behavior on all platforms, ie. no
|
|
* shared mappings of anon space (if the concepts are supported). */
|
|
#if defined(MAP_SHARED) && defined(MAP_PRIVATE)
|
|
flags = (flags & ~MAP_SHARED) | MAP_PRIVATE;
|
|
#endif /* defined(MAP_SHARED) && defined(MAP_PRIVATE) */
|
|
|
|
#ifdef MAP_ANONYMOUS
|
|
/* BSD-style anonymous mapping */
|
|
result = mmap(addr, len, prot, flags | MAP_ANONYMOUS, -1, offset);
|
|
#else
|
|
/* SysV-style anonymous mapping */
|
|
int fd;
|
|
fd = open("/dev/zero", O_RDWR);
|
|
if(fd < 0){
|
|
perror( "Cannot open /dev/zero for READ+WRITE. Check permissions! error: ");
|
|
return NULL;
|
|
}
|
|
|
|
result = mmap(addr, len, prot, flags, fd, offset);
|
|
close(fd);
|
|
#endif /* MAP_ANONYMOUS */
|
|
|
|
return result;
|
|
}
|