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 #ifdef __x86_64__
  33 #define __NR_preadv                             295
  34 #elif defined __i386__
  35 #define __NR_preadv             333
  36 #endif
  37
  38
  39 #ifndef PREADV
  40 # define PREADV preadv
  41 # define PREADV_REPLACEMENT __atomic_preadv_replacement
  42 # define PREAD __pread
  43 # define OFF_T off_t
  44 #endif
  45
  46 #ifndef __ASSUME_PREADV
  47 static ssize_t PREADV_REPLACEMENT (int, __const struct iovec *,
  48                                    int, OFF_T) internal_function;
  49 #endif
  50
  51
  52 ssize_t
  53 PREADV (fd, vector, count, offset)
  54      int fd;
  55      const struct iovec *vector;
  56      int count;
  57      OFF_T offset;
  58 {
  59 #ifdef __NR_preadv
  60   ssize_t result;
  61
  62   if (SINGLE_THREAD_P)
  63     result = INLINE_SYSCALL (preadv, 5, fd, vector, count,
  64                              (off_t) ((off64_t) offset >> 32),
  65                              (off_t) (offset & 0xffffffff));
  66   else
  67     {
  68       int oldtype = LIBC_CANCEL_ASYNC ();
  69
  70       result = INLINE_SYSCALL (preadv, 5, fd, vector, count,
  71                                (off_t) ((off64_t) offset >> 32),
  72                                (off_t) (offset & 0xffffffff));
  73
  74       LIBC_CANCEL_RESET (oldtype);
  75     }
  76 # ifdef __ASSUME_PREADV
  77   return result;
  78 # endif
  79 #endif
  80
  81 #ifndef __ASSUME_PREADV
  82 # ifdef __NR_preadv
  83   if (result >= 0 || errno != ENOSYS)
  84     return result;
  85 # endif
  86
  87   return PREADV_REPLACEMENT (fd, vector, count, offset);
  88 #endif
  89 }
  90 #if __WORDSIZE == 64
  91 # undef preadv64
  92 strong_alias (preadv, preadv64)
  93 #endif
  94
  95 #ifndef __ASSUME_PREADV
  96 # undef PREADV
  97 # define PREADV static internal_function PREADV_REPLACEMENT
  98 # include <sysdeps/posix/preadv.c>
  99 #endif