lib/read.c

   1 /* POSIX compatible read() function.
   2    Copyright (C) 2008-2021 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 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 General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #include <config.h>
  19
  20 /* Specification.  */
  21 #include <unistd.h>
  22
  23 #if 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 # if HAVE_MSVC_INVALID_PARAMETER_HANDLER
  32 #  include "msvc-inval.h"
  33 # endif
  34 # if GNULIB_MSVC_NOTHROW
  35 #  include "msvc-nothrow.h"
  36 # else
  37 #  include <io.h>
  38 # endif
  39
  40 /* Don't assume that UNICODE is not defined.  */
  41 # undef GetNamedPipeHandleState
  42 # define GetNamedPipeHandleState GetNamedPipeHandleStateA
  43
  44 # undef read
  45
  46 # if HAVE_MSVC_INVALID_PARAMETER_HANDLER
  47 static ssize_t
  48 read_nothrow (int fd, void *buf, size_t count)
  49 {
  50   ssize_t result;
  51
  52   TRY_MSVC_INVAL
  53     {
  54       result = _read (fd, buf, count);
  55     }
  56   CATCH_MSVC_INVAL
  57     {
  58       result = -1;
  59       errno = EBADF;
  60     }
  61   DONE_MSVC_INVAL;
  62
  63   return result;
  64 }
  65 # else
  66 #  define read_nothrow _read
  67 # endif
  68
  69 ssize_t
  70 rpl_read (int fd, void *buf, size_t count)
  71 {
  72   ssize_t ret = read_nothrow (fd, buf, count);
  73
  74 # if GNULIB_NONBLOCKING
  75   if (ret < 0
  76       && GetLastError () == ERROR_NO_DATA)
  77     {
  78       HANDLE h = (HANDLE) _get_osfhandle (fd);
  79       if (GetFileType (h) == FILE_TYPE_PIPE)
  80         {
  81           /* h is a pipe or socket.  */
  82           DWORD state;
  83           if (GetNamedPipeHandleState (h, &state, NULL, NULL, NULL, NULL, 0)
  84               && (state & PIPE_NOWAIT) != 0)
  85             /* h is a pipe in non-blocking mode.
  86                Change errno from EINVAL to EAGAIN.  */
  87             errno = EAGAIN;
  88         }
  89     }
  90 # endif
  91
  92   return ret;
  93 }
  94
  95 #endif