sysdeps/unix/sysv/linux/preadv.c

   1 /* Copyright (C) 2009-2014 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <stddef.h>
  20 #include <sys/param.h>
  21 #include <stdint.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
  33 #ifndef PREADV
  34 # define PREADV preadv
  35 # define PREADV_REPLACEMENT __atomic_preadv_replacement
  36 # define PREAD __pread
  37 # define OFF_T off_t
  38 #endif
  39
  40 #define LO_HI_LONG(val) \
  41   (off_t) val,                                                          \
  42   (off_t) ((((uint64_t) (val)) >> (sizeof (long) * 4)) >> (sizeof (long) * 4))
  43
  44 #ifndef __ASSUME_PREADV
  45 static ssize_t PREADV_REPLACEMENT (int, const struct iovec *,
  46                                    int, OFF_T) internal_function;
  47 #endif
  48
  49
  50 ssize_t
  51 PREADV (fd, vector, count, offset)
  52      int fd;
  53      const struct iovec *vector;
  54      int count;
  55      OFF_T offset;
  56 {
  57 #ifdef __NR_preadv
  58   ssize_t result;
  59
  60   if (SINGLE_THREAD_P)
  61     result = INLINE_SYSCALL (preadv, 5, fd, vector, count,
  62                              LO_HI_LONG (offset));
  63   else
  64     {
  65       int oldtype = LIBC_CANCEL_ASYNC ();
  66
  67       result = INLINE_SYSCALL (preadv, 5, fd, vector, count,
  68                                LO_HI_LONG (offset));
  69
  70       LIBC_CANCEL_RESET (oldtype);
  71     }
  72 # ifdef __ASSUME_PREADV
  73   return result;
  74 # endif
  75 #endif
  76
  77 #ifndef __ASSUME_PREADV
  78 # ifdef __NR_preadv
  79   if (result >= 0 || errno != ENOSYS)
  80     return result;
  81 # endif
  82
  83   return PREADV_REPLACEMENT (fd, vector, count, offset);
  84 #endif
  85 }
  86 #if __WORDSIZE == 64
  87 # undef preadv64
  88 strong_alias (preadv, preadv64)
  89 #endif
  90
  91 #ifndef __ASSUME_PREADV
  92 # undef PREADV
  93 # define PREADV static internal_function PREADV_REPLACEMENT
  94 # include <sysdeps/posix/preadv.c>
  95 #endif