lib/nonblocking.c

   1 /* Non-blocking I/O for pipe or socket descriptors.
   2    Copyright (C) 2011-2018 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program 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
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 /* Specification.  */
  20 #include "nonblocking.h"
  21
  22 #include <errno.h>
  23
  24 #if defined _WIN32 && ! defined __CYGWIN__
  25 /* Native Windows API.  */
  26
  27 # include <sys/ioctl.h>
  28 # include <sys/socket.h>
  29 # include <unistd.h>
  30
  31 /* Get declarations of the native Windows API functions.  */
  32 # define WIN32_LEAN_AND_MEAN
  33 # include <windows.h>
  34
  35 # if GNULIB_MSVC_NOTHROW
  36 #  include "msvc-nothrow.h"
  37 # else
  38 #  include <io.h>
  39 # endif
  40
  41 int
  42 get_nonblocking_flag (int desc)
  43 {
  44   HANDLE h = (HANDLE) _get_osfhandle (desc);
  45   if (h == INVALID_HANDLE_VALUE)
  46     {
  47       errno = EBADF;
  48       return -1;
  49     }
  50   if (GetFileType (h) == FILE_TYPE_PIPE)
  51     {
  52       /* h is a pipe or socket.  */
  53       DWORD state;
  54       if (GetNamedPipeHandleState (h, &state, NULL, NULL, NULL, NULL, 0))
  55         /* h is a pipe.  */
  56         return (state & PIPE_NOWAIT) != 0;
  57       else
  58         /* h is a socket.  */
  59         errno = ENOSYS;
  60         return -1;
  61     }
  62   else
  63     /* The native Windows API does not support non-blocking on regular
  64        files.  */
  65     return 0;
  66 }
  67
  68 int
  69 set_nonblocking_flag (int desc, bool value)
  70 {
  71   HANDLE h = (HANDLE) _get_osfhandle (desc);
  72   if (h == INVALID_HANDLE_VALUE)
  73     {
  74       errno = EBADF;
  75       return -1;
  76     }
  77   if (GetFileType (h) == FILE_TYPE_PIPE)
  78     {
  79       /* h is a pipe or socket.  */
  80       DWORD state;
  81       if (GetNamedPipeHandleState (h, &state, NULL, NULL, NULL, NULL, 0))
  82         {
  83           /* h is a pipe.  */
  84           if ((state & PIPE_NOWAIT) != 0)
  85             {
  86               if (value)
  87                 return 0;
  88               state &= ~PIPE_NOWAIT;
  89             }
  90           else
  91             {
  92               if (!value)
  93                 return 0;
  94               state |= PIPE_NOWAIT;
  95             }
  96           if (SetNamedPipeHandleState (h, &state, NULL, NULL))
  97             return 0;
  98           errno = EINVAL;
  99           return -1;
 100         }
 101       else
 102         {
 103           /* h is a socket.  */
 104           int v = value;
 105           return ioctl (desc, FIONBIO, &v);
 106         }
 107     }
 108   else
 109     {
 110       /* The native Windows API does not support non-blocking on regular
 111          files.  */
 112       if (!value)
 113         return 0;
 114       errno = ENOTSUP;
 115       return -1;
 116     }
 117 }
 118
 119 #else
 120 /* Unix API.  */
 121
 122 # include <fcntl.h>
 123
 124 # if GNULIB_defined_O_NONBLOCK
 125 #  error Please port nonblocking to your platform
 126 # endif
 127
 128 /* We don't need the gnulib replacement of fcntl() here.  */
 129 # undef fcntl
 130
 131 int
 132 get_nonblocking_flag (int desc)
 133 {
 134   int fcntl_flags;
 135
 136   fcntl_flags = fcntl (desc, F_GETFL, 0);
 137   if (fcntl_flags < 0)
 138     return -1;
 139   return (fcntl_flags & O_NONBLOCK) != 0;
 140 }
 141
 142 int
 143 set_nonblocking_flag (int desc, bool value)
 144 {
 145   int fcntl_flags;
 146
 147   fcntl_flags = fcntl (desc, F_GETFL, 0);
 148   if (fcntl_flags < 0)
 149     return -1;
 150   if (((fcntl_flags & O_NONBLOCK) != 0) == value)
 151     return 0;
 152   if (value)
 153     fcntl_flags |= O_NONBLOCK;
 154   else
 155     fcntl_flags &= ~O_NONBLOCK;
 156   return fcntl (desc, F_SETFL, fcntl_flags);
 157 }
 158
 159 #endif