sysdeps/unix/sysv/linux/truncate64.c

   1 /* Copyright (C) 1997-2000,2003,2004,2005,2006
   2         Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <sys/types.h>
  21 #include <endian.h>
  22 #include <errno.h>
  23 #include <unistd.h>
  24
  25 #include <sysdep.h>
  26 #include <sys/syscall.h>
  27 #include <bp-checks.h>
  28
  29 #include <kernel-features.h>
  30
  31 #ifdef __NR_truncate64
  32 #ifndef __ASSUME_TRUNCATE64_SYSCALL
  33 /* The variable is shared between all wrappers around *truncate64 calls.  */
  34 int __have_no_truncate64;
  35 #endif
  36
  37 /* Truncate the file FD refers to to LENGTH bytes.  */
  38 int
  39 truncate64 (const char *path, off64_t length)
  40 {
  41 #ifndef __ASSUME_TRUNCATE64_SYSCALL
  42   if (! __have_no_truncate64)
  43 #endif
  44     {
  45       unsigned int low = length & 0xffffffff;
  46       unsigned int high = length >> 32;
  47 #ifndef __ASSUME_TRUNCATE64_SYSCALL
  48       int saved_errno = errno;
  49 #endif
  50       int result = INLINE_SYSCALL (truncate64, 3, CHECK_STRING (path),
  51                                    __LONG_LONG_PAIR (high, low));
  52 #ifndef __ASSUME_TRUNCATE64_SYSCALL
  53       if (result != -1 || errno != ENOSYS)
  54 #endif
  55         return result;
  56
  57 #ifndef __ASSUME_TRUNCATE64_SYSCALL
  58       __set_errno (saved_errno);
  59       __have_no_truncate64 = 1;
  60 #endif
  61     }
  62
  63 #ifndef __ASSUME_TRUNCATE64_SYSCALL
  64   if ((off_t) length != length)
  65     {
  66       __set_errno (EINVAL);
  67       return -1;
  68     }
  69   return __truncate (path, (off_t) length);
  70 #endif
  71 }
  72
  73 #else
  74 /* Use the generic implementation.  */
  75 # include <misc/truncate64.c>
  76 #endif