/*

 * llseek.c -- stub calling the llseek system call

 *

 * Copyright (C) 1994, 1995, 1996, 1997 Theodore Ts'o.

 *

 * %Begin-Header%

 * This file may be redistributed under the terms of the GNU Library

 * General Public License, version 2.

 * %End-Header%

 */

#ifndef _LARGEFILE_SOURCE

#define _LARGEFILE_SOURCE

#endif

#ifndef _LARGEFILE64_SOURCE

#define _LARGEFILE64_SOURCE

#endif

#include "config.h"

#if HAVE_SYS_TYPES_H

#include <sys/types.h>

#endif

#if HAVE_ERRNO_H

#include <errno.h>

#endif

#if HAVE_UNISTD_H

#include <unistd.h>

#endif

#ifdef __MSDOS__

#include <io.h>

#endif

#include "et/com_err.h"

#include "ext2fs/ext2_io.h"

#ifdef __linux__

#include <linux/unistd.h>

static ext2_loff_t my_llseek (int fd, ext2_loff_t offset, int origin)

{

#if SIZEOF_OFF_T >= 8

  return lseek(fd, offset, origin);

#elif HAVE_LSEEK64_PROTOTYPE

  return lseek64(fd, offset, origin);

#elif HAVE_LLSEEK_PROTOTYPE

  return llseek(fd, offset, origin);

#elif defined(__NR__llseek)

  loff_t result;

  int retval;

  retval = syscall(__NR__llseek, fd,

    (unsigned long)(offset >> 32),

    (unsigned long)(offset & 0xffffffff),

    &result, origin);

  return (retval == -1 ? retval : result);

#else

  errno = ENOSYS;

  return -1;

#endif

}

ext2_loff_t ext2fs_llseek (int fd, ext2_loff_t offset, int origin)

{

  ext2_loff_t result;

  static int do_compat = 0;

  if (do_compat)

    goto fallback;

  result = my_llseek (fd, offset, origin);

  if (result == -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++;

  fallback:

    if (offset < ((ext2_loff_t) 1 << ((sizeof(off_t)*8) -1)))

      return lseek(fd, (off_t) offset, origin);

    errno = EINVAL;

    return -1;

  }

  return result;

}

#else /* !linux */

#ifndef EINVAL

#define EINVAL EXT2_ET_INVALID_ARGUMENT

#endif

ext2_loff_t ext2fs_llseek (int fd, ext2_loff_t offset, int origin)

{

#if defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE)

  return lseek64 (fd, offset, origin);

#else

  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

}

#endif  /* linux */