lib/sockets.c

   1 /* sockets.c --- wrappers for Windows socket functions
   2
   3    Copyright (C) 2008-2011 Free Software Foundation, Inc.
   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 /* Written by Simon Josefsson */
  19
  20 #include <config.h>
  21
  22 /* Specification.  */
  23 #include "sockets.h"
  24
  25 #if WINDOWS_SOCKETS
  26
  27 /* This includes winsock2.h on MinGW. */
  28 # include <sys/socket.h>
  29
  30 # include "fd-hook.h"
  31
  32 /* Get set_winsock_errno, FD_TO_SOCKET etc. */
  33 # include "w32sock.h"
  34
  35 static int
  36 close_fd_maybe_socket (const struct fd_hook *remaining_list,
  37                        gl_close_fn primary,
  38                        int fd)
  39 {
  40   /* Note about multithread-safety: There is a race condition where, between
  41      our calls to closesocket() and the primary close(), some other thread
  42      could make system calls that allocate precisely the same HANDLE value
  43      as sock; then the primary close() would call CloseHandle() on it.  */
  44   SOCKET sock;
  45   WSANETWORKEVENTS ev;
  46
  47   /* Test whether fd refers to a socket.  */
  48   sock = FD_TO_SOCKET (fd);
  49   ev.lNetworkEvents = 0xDEADBEEF;
  50   WSAEnumNetworkEvents (sock, NULL, &ev);
  51   if (ev.lNetworkEvents != 0xDEADBEEF)
  52     {
  53       /* fd refers to a socket.  */
  54       /* FIXME: other applications, like squid, use an undocumented
  55          _free_osfhnd free function.  But this is not enough: The 'osfile'
  56          flags for fd also needs to be cleared, but it is hard to access it.
  57          Instead, here we just close twice the file descriptor.  */
  58       if (closesocket (sock))
  59         {
  60           set_winsock_errno ();
  61           return -1;
  62         }
  63       else
  64         {
  65           /* This call frees the file descriptor and does a
  66              CloseHandle ((HANDLE) _get_osfhandle (fd)), which fails.  */
  67           _close (fd);
  68           return 0;
  69         }
  70     }
  71   else
  72     /* Some other type of file descriptor.  */
  73     return execute_close_hooks (remaining_list, primary, fd);
  74 }
  75
  76 static int
  77 ioctl_fd_maybe_socket (const struct fd_hook *remaining_list,
  78                        gl_ioctl_fn primary,
  79                        int fd, int request, void *arg)
  80 {
  81   SOCKET sock;
  82   WSANETWORKEVENTS ev;
  83
  84   /* Test whether fd refers to a socket.  */
  85   sock = FD_TO_SOCKET (fd);
  86   ev.lNetworkEvents = 0xDEADBEEF;
  87   WSAEnumNetworkEvents (sock, NULL, &ev);
  88   if (ev.lNetworkEvents != 0xDEADBEEF)
  89     {
  90       /* fd refers to a socket.  */
  91       if (ioctlsocket (sock, request, arg) < 0)
  92         {
  93           set_winsock_errno ();
  94           return -1;
  95         }
  96       else
  97         return 0;
  98     }
  99   else
 100     /* Some other type of file descriptor.  */
 101     return execute_ioctl_hooks (remaining_list, primary, fd, request, arg);
 102 }
 103
 104 static struct fd_hook fd_sockets_hook;
 105
 106 static int initialized_sockets_version /* = 0 */;
 107
 108 #endif /* WINDOWS_SOCKETS */
 109
 110 int
 111 gl_sockets_startup (int version _GL_UNUSED)
 112 {
 113 #if WINDOWS_SOCKETS
 114   if (version > initialized_sockets_version)
 115     {
 116       WSADATA data;
 117       int err;
 118
 119       err = WSAStartup (version, &data);
 120       if (err != 0)
 121         return 1;
 122
 123       if (data.wVersion < version)
 124         return 2;
 125
 126       if (initialized_sockets_version == 0)
 127         register_fd_hook (close_fd_maybe_socket, ioctl_fd_maybe_socket,
 128                           &fd_sockets_hook);
 129
 130       initialized_sockets_version = version;
 131     }
 132 #endif
 133
 134   return 0;
 135 }
 136
 137 int
 138 gl_sockets_cleanup (void)
 139 {
 140 #if WINDOWS_SOCKETS
 141   int err;
 142
 143   initialized_sockets_version = 0;
 144
 145   unregister_fd_hook (&fd_sockets_hook);
 146
 147   err = WSACleanup ();
 148   if (err != 0)
 149     return 1;
 150 #endif
 151
 152   return 0;
 153 }