uclibc-ng/libc/sysdeps/linux/common/lseek.c

/* vi: set sw=4 ts=4: */
/*
 * lseek() for uClibc
 *
 * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
 *
 * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
 */

#include <sys/syscall.h>
#include <unistd.h>
#include <cancel.h>

#ifdef __NR_lseek
# define __NR___lseek_nocancel __NR_lseek
_syscall3(off_t, __NC(lseek), int, fd, off_t, offset, int, whence)
/* Use lseek64 if __NR_lseek is not defined but UCLIBC_HAS_LFS is enabled */
#elif !defined __NR_lseek && defined __NR_llseek
#include <endian.h>
off_t __NC(lseek)(int fd, off_t offset, int whence)
{
#if defined __UCLIBC_HAS_LFS__
	return lseek64(fd, offset, whence);
#elif __WORDSIZE == 32
	__off64_t result;
	__off_t high = 0;
	return INLINE_SYSCALL(llseek, 5, fd,
				__LONG_LONG_PAIR(high, offset),
				&result, whence) ?: result;
#endif
/* No need to handle __WORDSIZE == 64 as such a kernel won't define __NR_llseek */
}
#else
# include <errno.h>
off_t __NC(lseek)(int fd, off_t offset attribute_unused, int whence)
{
	if (fd < 0) {
		__set_errno(EBADF);
		return -1;
	}

	switch(whence) {
		case SEEK_SET:
		case SEEK_CUR:
		case SEEK_END:
			break;
		default:
			__set_errno(EINVAL);
			return -1;
	}

	__set_errno(ENOSYS);
	return -1;
}
#endif
CANCELLABLE_SYSCALL(off_t, lseek, (int fd, off_t offset, int whence), (fd, offset, whence))
lt_libc_hidden(lseek)
#if defined __UCLIBC_HAS_LFS__ && (__WORDSIZE == 64 || (!defined __NR__llseek && !defined __NR_llseek))
strong_alias_untyped(__NC(lseek),__NC(lseek64))
strong_alias_untyped(lseek,lseek64)
lt_strong_alias(lseek64)
lt_libc_hidden(lseek64)
#endif