src/win32/plugin.c

   1 /*****************************************************************************
   2  * plugin.c : Low-level dynamic library handling
   3  *****************************************************************************
   4  * Copyright (C) 2001-2011 VLC authors and VideoLAN
   5  *
   6  * Authors: Sam Hocevar <sam@zoy.org>
   7  *          Ethan C. Baldridge <BaldridgeE@cadmus.com>
   8  *          Hans-Peter Jansen <hpj@urpla.net>
   9  *          Gildas Bazin <gbazin@videolan.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU Lesser General Public License as published by
  13  * the Free Software Foundation; either version 2.1 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  19  * GNU Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public License
  22  * along with this program; if not, write to the Free Software Foundation,
  23  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  24  *****************************************************************************/
  25
  26 #ifdef HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include <vlc_common.h>
  31 #include <vlc_charset.h>
  32 #include "modules/modules.h"
  33 #include <windows.h>
  34 #include <wchar.h>
  35
  36 extern DWORD LoadLibraryFlags;
  37
  38 #if (_WIN32_WINNT < _WIN32_WINNT_WIN7)
  39 static BOOL WINAPI SetThreadErrorModeFallback(DWORD mode, DWORD *oldmode)
  40 {
  41     /* TODO: cache the pointer */
  42     HANDLE h = GetModuleHandle(_T("kernel32.dll"));
  43     if (unlikely(h == NULL))
  44         return FALSE;
  45
  46     BOOL (WINAPI *SetThreadErrorModeReal)(DWORD, DWORD *);
  47
  48     SetThreadErrorModeReal = GetProcAddress(h, "SetThreadErrorMode");
  49     if (SetThreadErrorModeReal != NULL)
  50         return SetThreadErrorModeReal(mode, oldmode);
  51
  52 # if (_WIN32_WINNT < _WIN32_WINNT_VISTA)
  53     /* As per libvlc_new() documentation, the calling process is responsible
  54      * for setting a proper error mode on Windows 2008 and earlier versions.
  55      * This is only a sanity check. */
  56     UINT (WINAPI *GetErrorModeReal)(void);
  57     DWORD curmode = 0;
  58
  59     GetErrorModeReal = (void *)GetProcAddress(h, "GetErrorMode");
  60     if (GetErrorModeReal != NULL)
  61         curmode = GetErrorModeReal();
  62     else
  63         curmode = SEM_FAILCRITICALERRORS;
  64 # else
  65     DWORD curmode = GetErrorMode();
  66 # endif
  67     /* Extra flags should be OK. Missing flags are NOT OK. */
  68     if ((mode & curmode) != mode)
  69         return FALSE;
  70     if (oldmode != NULL)
  71         *oldmode = curmode;
  72     return TRUE;
  73 }
  74 # define SetThreadErrorMode SetThreadErrorModeFallback
  75 #endif
  76
  77 static char *GetWindowsError( void )
  78 {
  79     wchar_t wmsg[256];
  80     int i = 0, i_error = GetLastError();
  81
  82     FormatMessageW( FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
  83                     NULL, i_error, MAKELANGID (LANG_NEUTRAL, SUBLANG_DEFAULT),
  84                     wmsg, 256, NULL );
  85
  86     /* Go to the end of the string */
  87     while( !wmemchr( L"\r\n\0", wmsg[i], 3 ) )
  88         i++;
  89
  90     snwprintf( wmsg + i, 256 - i, L" (error %i)", i_error );
  91     return FromWide( wmsg );
  92 }
  93
  94 int module_Load( vlc_object_t *p_this, const char *psz_file,
  95                  module_handle_t *p_handle, bool lazy )
  96 {
  97     wchar_t *wfile = ToWide (psz_file);
  98     if (wfile == NULL)
  99         return -1;
 100
 101     module_handle_t handle = NULL;
 102 #if !VLC_WINSTORE_APP
 103     DWORD mode;
 104     if (SetThreadErrorMode (SEM_FAILCRITICALERRORS, &mode) != 0)
 105     {
 106         handle = LoadLibraryExW (wfile, NULL, LoadLibraryFlags );
 107         SetThreadErrorMode (mode, NULL);
 108     }
 109 #else
 110     handle = LoadPackagedLibrary( wfile, 0 );
 111 #endif
 112     free (wfile);
 113
 114     if( handle == NULL )
 115     {
 116         char *psz_err = GetWindowsError();
 117         msg_Warn( p_this, "cannot load module `%s' (%s)", psz_file, psz_err );
 118         free( psz_err );
 119         return -1;
 120     }
 121
 122     *p_handle = handle;
 123     (void) lazy;
 124     return 0;
 125 }
 126
 127 void module_Unload( module_handle_t handle )
 128 {
 129     FreeLibrary( handle );
 130 }
 131
 132 void *module_Lookup( module_handle_t handle, const char *psz_function )
 133 {
 134     return (void *)GetProcAddress( handle, (char *)psz_function );
 135 }