sysdeps/unix/sysv/linux/pwrite.c

   1 /* Copyright (C) 1997-2015 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 #ifdef __NR_pwrite64            /* Newer kernels renamed but it's the same.  */
  28 # ifdef __NR_pwrite
  29 #  error "__NR_pwrite and __NR_pwrite64 both defined???"
  30 # endif
  31 # define __NR_pwrite __NR_pwrite64
  32 #endif
  33
  34
  35 static ssize_t
  36 #ifdef NO_CANCELLATION
  37 inline __attribute ((always_inline))
  38 #endif
  39 do_pwrite (int fd, const void *buf, size_t count, off_t offset)
  40 {
  41   ssize_t result;
  42
  43   assert (sizeof (offset) == 4);
  44   result = INLINE_SYSCALL (pwrite, 5, fd, buf, count,
  45                            __LONG_LONG_PAIR (offset >> 31, offset));
  46
  47   return result;
  48 }
  49
  50
  51 ssize_t
  52 __libc_pwrite (fd, buf, count, offset)
  53      int fd;
  54      const void *buf;
  55      size_t count;
  56      off_t offset;
  57 {
  58   if (SINGLE_THREAD_P)
  59     return do_pwrite (fd, buf, count, offset);
  60
  61   int oldtype = LIBC_CANCEL_ASYNC ();
  62
  63   ssize_t result = do_pwrite (fd, buf, count, offset);
  64
  65   LIBC_CANCEL_RESET (oldtype);
  66
  67   return result;
  68 }
  69
  70 strong_alias (__libc_pwrite, __pwrite)
  71 weak_alias (__libc_pwrite, pwrite)