sysdeps/unix/sysv/linux/preadv.c

   1 /* Copyright (C) 2009 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 <errno.h>
  20 #include <stddef.h>
  21 #include <sys/param.h>
  22 #if __WORDSIZE == 64
  23 /* Hide the preadv64 declaration.  */
  24 # define preadv64 __redirect_preadv64
  25 #endif
  26 #include <sys/uio.h>
  27
  28 #include <sysdep-cancel.h>
  29 #include <sys/syscall.h>
  30 #include <kernel-features.h>
  31
  32 #ifndef PREADV
  33 # define PREADV preadv
  34 # define PREADV_REPLACEMENT __atomic_preadv_replacement
  35 # define PREAD __pread
  36 # define OFF_T off_t
  37 #endif
  38
  39 static ssize_t PREADV_REPLACEMENT (int, __const struct iovec *,
  40                                    int, OFF_T) internal_function;
  41
  42
  43 ssize_t
  44 PREADV (fd, vector, count, offset)
  45      int fd;
  46      const struct iovec *vector;
  47      int count;
  48      OFF_T offset;
  49 {
  50 #ifdef __NR_preadv
  51   ssize_t result;
  52
  53   if (SINGLE_THREAD_P)
  54     result = INLINE_SYSCALL (preadv, 5, fd, vector, count, offset >> 32,
  55                              offset & 0xffffffff);
  56   else
  57     {
  58       int oldtype = LIBC_CANCEL_ASYNC ();
  59
  60       result = INLINE_SYSCALL (preadv, 5, fd, vector, count, offset >> 32,
  61                                offset & 0xffffffff);
  62
  63       LIBC_CANCEL_RESET (oldtype);
  64     }
  65 # ifdef __ASSUME_PREADV
  66   return result;
  67 # endif
  68 #endif
  69
  70 #ifndef __ASSUME_PREADV
  71 # ifdef __NR_preadv
  72   if (result >= 0 || errno != ENOSYS)
  73     return result;
  74 # endif
  75
  76   return PREADV_REPLACEMENT (fd, vector, count, offset);
  77 #endif
  78 }
  79 #if __WORDSIZE == 64
  80 # undef preadv64
  81 strong_alias (preadv, preadv64)
  82 #endif
  83
  84 #ifndef __ASSUME_PREADV
  85 # undef PREADV
  86 # define PREADV static internal_function PREADV_REPLACEMENT
  87 # include <sysdeps/posix/preadv.c>
  88 #endif