busybox/e2fsprogs/blkid/llseek.c

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/*
* 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 Lesser General Public License.
* %End-Header%
*/
#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
#include "blkidP.h"
#ifdef CONFIG_LFS
# define my_llseek lseek64
#else
# define my_llseek lseek
#endif
blkid_loff_t blkid_llseek(int fd, blkid_loff_t offset, int whence)
{
blkid_loff_t result;
static int do_compat = 0;
if ((sizeof(off_t) >= sizeof(blkid_loff_t)) ||
(offset < ((blkid_loff_t) 1 << ((sizeof(off_t)*8) -1))))
return lseek(fd, (off_t) offset, whence);
if (do_compat) {
errno = EOVERFLOW;
return -1;
}
result = my_llseek(fd, offset, whence);
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++;
errno = EOVERFLOW;
}
return result;
}