sysdeps/unix/sysv/linux/pwrite.c

   1 /* Copyright (C) 1997-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <assert.h>
  20 #include <errno.h>
  21 #include <endian.h>
  22 #include <unistd.h>
  23
  24 #include <sysdep-cancel.h>
  25 #include <sys/syscall.h>
  26
  27 #include <kernel-features.h>
  28
  29 #ifdef __NR_pwrite64            /* Newer kernels renamed but it's the same.  */
  30 # ifdef __NR_pwrite
  31 #  error "__NR_pwrite and __NR_pwrite64 both defined???"
  32 # endif
  33 # define __NR_pwrite __NR_pwrite64
  34 #endif
  35
  36
  37 static ssize_t
  38 #ifdef NO_CANCELLATION
  39 inline __attribute ((always_inline))
  40 #endif
  41 do_pwrite (int fd, const void *buf, size_t count, off_t offset)
  42 {
  43   ssize_t result;
  44
  45   assert (sizeof (offset) == 4);
  46   result = INLINE_SYSCALL (pwrite, 5, fd, buf, count,
  47                            __LONG_LONG_PAIR (offset >> 31, offset));
  48
  49   return result;
  50 }
  51
  52
  53 ssize_t
  54 __libc_pwrite (fd, buf, count, offset)
  55      int fd;
  56      const void *buf;
  57      size_t count;
  58      off_t offset;
  59 {
  60   if (SINGLE_THREAD_P)
  61     return do_pwrite (fd, buf, count, offset);
  62
  63   int oldtype = LIBC_CANCEL_ASYNC ();
  64
  65   ssize_t result = do_pwrite (fd, buf, count, offset);
  66
  67   LIBC_CANCEL_RESET (oldtype);
  68
  69   return result;
  70 }
  71
  72 strong_alias (__libc_pwrite, __pwrite)
  73 weak_alias (__libc_pwrite, pwrite)