sysdeps/unix/sysv/linux/ftruncate64.c

   1 /* Copyright (C) 1997,1998,1999,2000,2001,2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <sys/types.h>
  20 #include <errno.h>
  21 #include <endian.h>
  22 #include <unistd.h>
  23
  24 #include <sysdep.h>
  25 #include <sys/syscall.h>
  26
  27 #include "kernel-features.h"
  28
  29 #ifdef __NR_ftruncate64
  30 #ifndef __ASSUME_TRUNCATE64_SYSCALL
  31 /* The variable is shared between all wrappers around *truncate64 calls.  */
  32 extern int __have_no_truncate64;
  33 #endif
  34
  35
  36 /* Truncate the file FD refers to to LENGTH bytes.  */
  37 int
  38 __ftruncate64 (int fd, off64_t length)
  39 {
  40 #ifndef __ASSUME_TRUNCATE64_SYSCALL
  41   if (! __have_no_truncate64)
  42 #endif
  43     {
  44       unsigned int low = length & 0xffffffff;
  45       unsigned int high = length >> 32;
  46 #ifndef __ASSUME_TRUNCATE64_SYSCALL
  47       int saved_errno = errno;
  48 #endif
  49       int result = INLINE_SYSCALL (ftruncate64, 3, fd,
  50                                    __LONG_LONG_PAIR (high, low));
  51 #ifndef __ASSUME_TRUNCATE64_SYSCALL
  52       if (result != -1 || errno != ENOSYS)
  53 #endif
  54         return result;
  55
  56 #ifndef __ASSUME_TRUNCATE64_SYSCALL
  57       __set_errno (saved_errno);
  58       __have_no_truncate64 = 1;
  59 #endif
  60     }
  61
  62 #ifndef __ASSUME_TRUNCATE64_SYSCALL
  63   if ((off_t) length != length)
  64     {
  65       __set_errno (EINVAL);
  66       return -1;
  67     }
  68   return __ftruncate (fd, (off_t) length);
  69 #endif
  70 }
  71 weak_alias (__ftruncate64, ftruncate64)
  72
  73 #else
  74 /* Use the generic implementation.  */
  75 # include <sysdeps/generic/ftruncate64.c>
  76 #endif