sysdeps/unix/sysv/linux/preadv.c

   1 /* Copyright (C) 2009-2013 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 #if __WORDSIZE == 64
  22 /* Hide the preadv64 declaration.  */
  23 # define preadv64 __redirect_preadv64
  24 #endif
  25 #include <sys/uio.h>
  26
  27 #include <sysdep-cancel.h>
  28 #include <sys/syscall.h>
  29 #include <kernel-features.h>
  30
  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 #define LO_HI_LONG(val) \
  40   (off_t) val,                                                          \
  41   (off_t) ((((uint64_t) (val)) >> (sizeof (long) * 4)) >> (sizeof (long) * 4))
  42
  43 #ifndef __ASSUME_PREADV
  44 static ssize_t PREADV_REPLACEMENT (int, const struct iovec *,
  45                                    int, OFF_T) internal_function;
  46 #endif
  47
  48
  49 ssize_t
  50 PREADV (fd, vector, count, offset)
  51      int fd;
  52      const struct iovec *vector;
  53      int count;
  54      OFF_T offset;
  55 {
  56 #ifdef __NR_preadv
  57   ssize_t result;
  58
  59   if (SINGLE_THREAD_P)
  60     result = INLINE_SYSCALL (preadv, 5, fd, vector, count,
  61                              LO_HI_LONG (offset));
  62   else
  63     {
  64       int oldtype = LIBC_CANCEL_ASYNC ();
  65
  66       result = INLINE_SYSCALL (preadv, 5, fd, vector, count,
  67                                LO_HI_LONG (offset));
  68
  69       LIBC_CANCEL_RESET (oldtype);
  70     }
  71 # ifdef __ASSUME_PREADV
  72   return result;
  73 # endif
  74 #endif
  75
  76 #ifndef __ASSUME_PREADV
  77 # ifdef __NR_preadv
  78   if (result >= 0 || errno != ENOSYS)
  79     return result;
  80 # endif
  81
  82   return PREADV_REPLACEMENT (fd, vector, count, offset);
  83 #endif
  84 }
  85 #if __WORDSIZE == 64
  86 # undef preadv64
  87 strong_alias (preadv, preadv64)
  88 #endif
  89
  90 #ifndef __ASSUME_PREADV
  91 # undef PREADV
  92 # define PREADV static internal_function PREADV_REPLACEMENT
  93 # include <sysdeps/posix/preadv.c>
  94 #endif