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