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/*
* 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.
*
* This file is borrowed from the util-linux-2.11z tarball's implementation
* of fdisk. It allows seeks to 64 bit offsets, if supported.
* Changed "ext2_" prefix to "llse".
*/
#include "config.h"
#define _XOPEN_SOURCE 500
#define _GNU_SOURCE
#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#if defined(__GNUC__) || defined(HAS_LONG_LONG)
typedef int64_t llse_loff_t;
#else
typedef long llse_loff_t;
#endif
extern llse_loff_t llse_llseek (unsigned int, llse_loff_t, unsigned int);
#ifdef __linux__
#ifdef HAVE_LLSEEK
#include <syscall.h>
#else /* HAVE_LLSEEK */
#if defined(__alpha__) || defined(__ia64__) || defined(__s390x__) || defined (__x86_64__) || defined (__powerpc64__)
#define my_llseek lseek
#else
#include <linux/unistd.h> /* for __NR__llseek */
static int _llseek (unsigned int, unsigned long,
unsigned long, llse_loff_t *, unsigned int);
#ifdef __NR__llseek
static _syscall5(int,_llseek,unsigned int,fd,unsigned long,offset_high,
unsigned long, offset_low,llse_loff_t *,result,
unsigned int, origin)
#else
/* no __NR__llseek on compilation machine - might give it explicitly */
static int _llseek (unsigned int fd, unsigned long oh,
unsigned long ol, llse_loff_t *result,
unsigned int origin) {
errno = ENOSYS;
return -1;
}
#endif
static llse_loff_t my_llseek (unsigned int fd, llse_loff_t offset,
unsigned int origin)
{
llse_loff_t result;
int retval;
#ifdef HAVE_LSEEK64
return lseek64 (fd, offset, origin);
#else
retval = _llseek (fd, ((uint64_t) offset) >> 32,
((uint64_t) offset) & 0xffffffff,
&result, origin);
return (retval == -1 ? (llse_loff_t) retval : result);
#endif
}
#endif /* __alpha__ */
#endif /* HAVE_LLSEEK */
llse_loff_t llse_llseek (unsigned int fd, llse_loff_t offset,
unsigned int origin)
{
llse_loff_t result;
static int do_compat = 0;
if (!do_compat) {
result = my_llseek (fd, offset, origin);
if (!(result == -1 && errno == ENOSYS))
return result;
/*
* Just in case this code runs on top of an old kernel
* which does not support the llseek system call
*/
do_compat = 1;
/*
* Now try ordinary lseek.
*/
}
if ((sizeof(off_t) >= sizeof(llse_loff_t)) ||
(offset < ((llse_loff_t) 1 << ((sizeof(off_t)*8) -1))))
return lseek(fd, (off_t) offset, origin);
errno = EINVAL;
return -1;
}
#else /* !linux */
llse_loff_t llse_llseek (unsigned int fd, llse_loff_t offset,
unsigned int origin)
{
if ((sizeof(off_t) < sizeof(llse_loff_t)) &&
(offset >= ((llse_loff_t) 1 << ((sizeof(off_t)*8) -1)))) {
errno = EINVAL;
return -1;
}
return lseek (fd, (off_t) offset, origin);
}
#endif /* linux */
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