lib/read.c

   1 /* POSIX compatible read() function.
   2    Copyright (C) 2008-2012 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2011.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include <config.h>
  19
  20 /* Specification.  */
  21 #include <unistd.h>
  22
  23 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
  24
  25 # include <errno.h>
  26 # include <io.h>
  27
  28 # define WIN32_LEAN_AND_MEAN  /* avoid including junk */
  29 # include <windows.h>
  30
  31 # include "msvc-inval.h"
  32 # include "msvc-nothrow.h"
  33
  34 # undef read
  35
  36 # if HAVE_MSVC_INVALID_PARAMETER_HANDLER
  37 static inline ssize_t
  38 read_nothrow (int fd, void *buf, size_t count)
  39 {
  40   ssize_t result;
  41
  42   TRY_MSVC_INVAL
  43     {
  44       result = read (fd, buf, count);
  45     }
  46   CATCH_MSVC_INVAL
  47     {
  48       result = -1;
  49       errno = EBADF;
  50     }
  51   DONE_MSVC_INVAL;
  52
  53   return result;
  54 }
  55 # else
  56 #  define read_nothrow read
  57 # endif
  58
  59 ssize_t
  60 rpl_read (int fd, void *buf, size_t count)
  61 {
  62   ssize_t ret = read_nothrow (fd, buf, count);
  63
  64 # if GNULIB_NONBLOCKING
  65   if (ret < 0
  66       && GetLastError () == ERROR_NO_DATA)
  67     {
  68       HANDLE h = (HANDLE) _get_osfhandle (fd);
  69       if (GetFileType (h) == FILE_TYPE_PIPE)
  70         {
  71           /* h is a pipe or socket.  */
  72           DWORD state;
  73           if (GetNamedPipeHandleState (h, &state, NULL, NULL, NULL, NULL, 0)
  74               && (state & PIPE_NOWAIT) != 0)
  75             /* h is a pipe in non-blocking mode.
  76                Change errno from EINVAL to EAGAIN.  */
  77             errno = EAGAIN;
  78         }
  79     }
  80 # endif
  81
  82   return ret;
  83 }
  84
  85 #endif