e2fsprogs/lib/ext2fs/llseek.c

80 lines
1.8 KiB
C

/*
* llseek.c -- stub calling the llseek system call
*
* Copyright (C) 1994 Remy Card. This file may be redistributed
* under the terms of the GNU Public License.
*/
#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include <linux/unistd.h>
#include "et/com_err.h"
#include "ext2fs/io.h"
#ifdef __linux__
#ifndef __NR__llseek
#define __NR__llseek 140
#endif
static int _llseek (unsigned int, unsigned long,
unsigned long, ext2_loff_t *, unsigned int);
static _syscall5(int,_llseek,unsigned int,fd,unsigned long,offset_high,
unsigned long, offset_low,ext2_loff_t *,result,
unsigned int, origin)
ext2_loff_t ext2_llseek (unsigned int fd, ext2_loff_t offset,
unsigned int origin)
{
unsigned long offset_high;
unsigned long offset_low;
ext2_loff_t result;
int retval;
static int do_compat = 0;
if (do_compat) {
compat_lseek:
if ((sizeof(off_t) < sizeof(ext2_loff_t)) &&
(offset >= ((ext2_loff_t) 1 << ((sizeof(off_t)*8) -1)))) {
errno = -EINVAL;
return -1;
}
return lseek (fd, (off_t) offset, origin);
}
offset_high = ((unsigned long long) offset) >> 32;
offset_low = ((unsigned long long) offset) & 0xffffffff;
retval = _llseek (fd, offset_high, offset_low, &result, origin);
if (retval == -1 && errno == ENOSYS) {
/*
* Just in case this code runs on top of an old kernel
* which does not support the llseek system call
*/
do_compat++;
goto compat_lseek;
}
if (retval == -1)
result = -1;
return result;
}
#else
ext2_loff_t ext2_llseek (unsigned int fd, ext2_loff_t offset,
unsigned int origin)
{
if ((sizeof(off_t) < sizeof(ext2_loff_t)) &&
(offset >= ((ext2_loff_t) 1 << ((sizeof(off_t)*8) -1)))) {
errno = -EINVAL;
return -1;
}
return lseek (fd, (off_t) offset, origin);
}
#endif