glibc/sysdeps/unix/sysv/linux/ftruncate64.c
2012-02-09 23:18:22 +00:00

77 lines
2.1 KiB
C

/* Copyright (C) 1997,1998,1999,2000,2001,2003,2005,2006,2011
Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <sys/types.h>
#include <errno.h>
#include <endian.h>
#include <unistd.h>
#include <sysdep.h>
#include <sys/syscall.h>
#include <kernel-features.h>
#ifdef __NR_ftruncate64
#ifndef __ASSUME_TRUNCATE64_SYSCALL
/* The variable is shared between all wrappers around *truncate64 calls. */
extern int __have_no_truncate64;
#endif
/* Truncate the file referenced by FD to LENGTH bytes. */
int
__ftruncate64 (int fd, off64_t length)
{
#ifndef __ASSUME_TRUNCATE64_SYSCALL
if (! __have_no_truncate64)
#endif
{
unsigned int low = length & 0xffffffff;
unsigned int high = length >> 32;
#ifndef __ASSUME_TRUNCATE64_SYSCALL
int saved_errno = errno;
#endif
int result = INLINE_SYSCALL (ftruncate64, 3, fd,
__LONG_LONG_PAIR (high, low));
#ifndef __ASSUME_TRUNCATE64_SYSCALL
if (result != -1 || errno != ENOSYS)
#endif
return result;
#ifndef __ASSUME_TRUNCATE64_SYSCALL
__set_errno (saved_errno);
__have_no_truncate64 = 1;
#endif
}
#ifndef __ASSUME_TRUNCATE64_SYSCALL
if ((off_t) length != length)
{
__set_errno (EINVAL);
return -1;
}
return __ftruncate (fd, (off_t) length);
#endif
}
weak_alias (__ftruncate64, ftruncate64)
#else
/* Use the generic implementation. */
# include <misc/ftruncate64.c>
#endif