File: loadlibrary.c

package info (click to toggle)
libprelude 4.1.0-4.2
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 21,452 kB
  • sloc: ansic: 103,807; cpp: 64,944; sh: 13,563; perl: 679; makefile: 674; awk: 343; yacc: 241; lex: 178; python: 89; xml: 65
file content (369 lines) | stat: -rw-r--r-- 10,875 bytes parent folder | download | duplicates (71)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
/* loader-loadlibrary.c --  dynamic linking for Win32

   Copyright (C) 1998, 1999, 2000, 2004, 2005, 2006,
                 2007, 2008, 2010 Free Software Foundation, Inc.
   Written by Thomas Tanner, 1998

   NOTE: The canonical source of this file is maintained with the
   GNU Libtool package.  Report bugs to bug-libtool@gnu.org.

GNU Libltdl is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

As a special exception to the GNU Lesser General Public License,
if you distribute this file as part of a program or library that
is built using GNU Libtool, you may include this file under the
same distribution terms that you use for the rest of that program.

GNU Libltdl is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with GNU Libltdl; see the file COPYING.LIB.  If not, a
copy can be downloaded from  http://www.gnu.org/licenses/lgpl.html,
or obtained by writing to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/

#include "lt__private.h"
#include "lt_dlloader.h"

#if defined(__CYGWIN__)
# include <sys/cygwin.h>
#endif

/* Use the preprocessor to rename non-static symbols to avoid namespace
   collisions when the loader code is statically linked into libltdl.
   Use the "<module_name>_LTX_" prefix so that the symbol addresses can
   be fetched from the preloaded symbol list by lt_dlsym():  */
#define get_vtable	loadlibrary_LTX_get_vtable

LT_BEGIN_C_DECLS
LT_SCOPE lt_dlvtable *get_vtable (lt_user_data loader_data);
LT_END_C_DECLS


/* Boilerplate code to set up the vtable for hooking this loader into
   libltdl's loader list:  */
static int	 vl_exit  (lt_user_data loader_data);
static lt_module vm_open  (lt_user_data loader_data, const char *filename,
                           lt_dladvise advise);
static int	 vm_close (lt_user_data loader_data, lt_module module);
static void *	 vm_sym   (lt_user_data loader_data, lt_module module,
			  const char *symbolname);

static lt_dlinterface_id iface_id = 0;
static lt_dlvtable *vtable = 0;

/* Return the vtable for this loader, only the name and sym_prefix
   attributes (plus the virtual function implementations, obviously)
   change between loaders.  */
lt_dlvtable *
get_vtable (lt_user_data loader_data)
{
  if (!vtable)
    {
      vtable = (lt_dlvtable *) lt__zalloc (sizeof *vtable);
      iface_id = lt_dlinterface_register ("ltdl loadlibrary", NULL);
    }

  if (vtable && !vtable->name)
    {
      vtable->name		= "lt_loadlibrary";
      vtable->module_open	= vm_open;
      vtable->module_close	= vm_close;
      vtable->find_sym		= vm_sym;
      vtable->dlloader_exit	= vl_exit;
      vtable->dlloader_data	= loader_data;
      vtable->priority		= LT_DLLOADER_APPEND;
    }

  if (vtable && (vtable->dlloader_data != loader_data))
    {
      LT__SETERROR (INIT_LOADER);
      return 0;
    }

  return vtable;
}



/* --- IMPLEMENTATION --- */


#include <windows.h>

#define LOCALFREE(mem)					     LT_STMT_START { \
	if (mem) { LocalFree ((void *)mem); mem = NULL; }    } LT_STMT_END
#define LOADLIB__SETERROR(errmsg) LT__SETERRORSTR (loadlibraryerror (errmsg))
#define LOADLIB_SETERROR(errcode) LOADLIB__SETERROR (LT__STRERROR (errcode))

static const char *loadlibraryerror (const char *default_errmsg);
static DWORD WINAPI wrap_getthreaderrormode (void);
static DWORD WINAPI fallback_getthreaderrormode (void);
static BOOL WINAPI wrap_setthreaderrormode (DWORD mode, DWORD *oldmode);
static BOOL WINAPI fallback_setthreaderrormode (DWORD mode, DWORD *oldmode);

typedef DWORD (WINAPI getthreaderrormode_type) (void);
typedef BOOL (WINAPI setthreaderrormode_type) (DWORD, DWORD *);

static getthreaderrormode_type *getthreaderrormode = wrap_getthreaderrormode;
static setthreaderrormode_type *setthreaderrormode = wrap_setthreaderrormode;
static char *error_message = 0;


/* A function called through the vtable when this loader is no
   longer needed by the application.  */
static int
vl_exit (lt_user_data LT__UNUSED loader_data)
{
  vtable = NULL;
  LOCALFREE (error_message);
  return 0;
}

/* A function called through the vtable to open a module with this
   loader.  Returns an opaque representation of the newly opened
   module for processing with this loader's other vtable functions.  */
static lt_module
vm_open (lt_user_data LT__UNUSED loader_data, const char *filename,
         lt_dladvise LT__UNUSED advise)
{
  lt_module	module	   = 0;
  char		*ext;
  char		wpath[MAX_PATH];
  size_t	len;

  if (!filename)
    {
      /* Get the name of main module */
      *wpath = 0;
      GetModuleFileName (NULL, wpath, sizeof (wpath));
      filename = wpath;
    }
  else
    {
      len = LT_STRLEN (filename);

      if (len >= MAX_PATH)
        {
	  LT__SETERROR (CANNOT_OPEN);
	  return 0;
	}

#if HAVE_DECL_CYGWIN_CONV_PATH
      if (cygwin_conv_path (CCP_POSIX_TO_WIN_A, filename, wpath, MAX_PATH))
	{
	  LT__SETERROR (CANNOT_OPEN);
	  return 0;
	}
      len = 0;
#elif defined(__CYGWIN__)
      cygwin_conv_to_full_win32_path (filename, wpath);
      len = 0;
#else
      strcpy(wpath, filename);
#endif

      ext = strrchr (wpath, '.');
      if (!ext)
	{
	  /* Append a `.' to stop Windows from adding an
	     implicit `.dll' extension. */
	  if (!len)
	    len = strlen (wpath);

	  if (len + 1 >= MAX_PATH)
	    {
	      LT__SETERROR (CANNOT_OPEN);
	      return 0;
	    }

	  wpath[len] = '.';
	  wpath[len+1] = '\0';
	}
    }

  {
    /* Silence dialog from LoadLibrary on some failures. */
    DWORD errormode = getthreaderrormode ();
    DWORD last_error;

    setthreaderrormode (errormode | SEM_FAILCRITICALERRORS, NULL);

    module = LoadLibrary (wpath);

    /* Restore the error mode. */
    last_error = GetLastError ();
    setthreaderrormode (errormode, NULL);
    SetLastError (last_error);
  }

  /* libltdl expects this function to fail if it is unable
     to physically load the library.  Sadly, LoadLibrary
     will search the loaded libraries for a match and return
     one of them if the path search load fails.

     We check whether LoadLibrary is returning a handle to
     an already loaded module, and simulate failure if we
     find one. */
  {
    lt_dlhandle cur = 0;

    while ((cur = lt_dlhandle_iterate (iface_id, cur)))
      {
        if (!cur->module)
          {
            cur = 0;
            break;
          }

        if (cur->module == module)
          {
            break;
          }
      }

    if (!module)
      LOADLIB_SETERROR (CANNOT_OPEN);
    else if (cur)
      {
        LT__SETERROR (CANNOT_OPEN);
        module = 0;
      }
  }

  return module;
}


/* A function called through the vtable when a particular module
   should be unloaded.  */
static int
vm_close (lt_user_data LT__UNUSED loader_data, lt_module module)
{
  int errors = 0;

  if (FreeLibrary ((HMODULE) module) == 0)
    {
      LOADLIB_SETERROR (CANNOT_CLOSE);
      ++errors;
    }

  return errors;
}


/* A function called through the vtable to get the address of
   a symbol loaded from a particular module.  */
static void *
vm_sym (lt_user_data LT__UNUSED loader_data, lt_module module, const char *name)
{
  void *address = (void *) GetProcAddress ((HMODULE) module, name);

  if (!address)
    {
      LOADLIB_SETERROR (SYMBOL_NOT_FOUND);
    }

  return address;
}



/* --- HELPER FUNCTIONS --- */


/* Return the windows error message, or the passed in error message on
   failure. */
static const char *
loadlibraryerror (const char *default_errmsg)
{
  size_t len;
  LOCALFREE (error_message);

  FormatMessageA (FORMAT_MESSAGE_ALLOCATE_BUFFER |
                  FORMAT_MESSAGE_FROM_SYSTEM |
                  FORMAT_MESSAGE_IGNORE_INSERTS,
                  NULL,
                  GetLastError (),
                  0,
                  (char *) &error_message,
                  0, NULL);

  /* Remove trailing CRNL */
  len = LT_STRLEN (error_message);
  if (len && error_message[len - 1] == '\n')
    error_message[--len] = LT_EOS_CHAR;
  if (len && error_message[len - 1] == '\r')
    error_message[--len] = LT_EOS_CHAR;

  return len ? error_message : default_errmsg;
}

/* A function called through the getthreaderrormode variable which checks
   if the system supports GetThreadErrorMode (or GetErrorMode) and arranges
   for it or a fallback implementation to be called directly in the future.
   The selected version is then called. */
static DWORD WINAPI
wrap_getthreaderrormode (void)
{
  HMODULE kernel32 = GetModuleHandleA ("kernel32.dll");
  getthreaderrormode
    = (getthreaderrormode_type *) GetProcAddress (kernel32,
						  "GetThreadErrorMode");
  if (!getthreaderrormode)
    getthreaderrormode
      = (getthreaderrormode_type *) GetProcAddress (kernel32,
						    "GetErrorMode");
  if (!getthreaderrormode)
    getthreaderrormode = fallback_getthreaderrormode;
  return getthreaderrormode ();
}

/* A function called through the getthreaderrormode variable for cases
   where the system does not support GetThreadErrorMode or GetErrorMode */
static DWORD WINAPI
fallback_getthreaderrormode (void)
{
  /* Prior to Windows Vista, the only way to get the current error
     mode was to set a new one. In our case, we are setting a new
     error mode right after "getting" it while ignoring the error
     mode in effect when setting the new error mode, so that's
     fairly ok. */
  return (DWORD) SetErrorMode (SEM_FAILCRITICALERRORS);
}

/* A function called through the setthreaderrormode variable which checks
   if the system supports SetThreadErrorMode and arranges for it or a
   fallback implementation to be called directly in the future.
   The selected version is then called. */
static BOOL WINAPI
wrap_setthreaderrormode (DWORD mode, DWORD *oldmode)
{
  HMODULE kernel32 = GetModuleHandleA ("kernel32.dll");
  setthreaderrormode
    = (setthreaderrormode_type *) GetProcAddress (kernel32,
						  "SetThreadErrorMode");
  if (!setthreaderrormode)
    setthreaderrormode = fallback_setthreaderrormode;
  return setthreaderrormode (mode, oldmode);
}

/* A function called through the setthreaderrormode variable for cases
   where the system does not support SetThreadErrorMode. */
static BOOL WINAPI
fallback_setthreaderrormode (DWORD mode, DWORD *oldmode)
{
  /* Prior to Windows 7, there was no way to set the thread local error
     mode, so set the process global error mode instead. */
  DWORD old = (DWORD) SetErrorMode (mode);
  if (oldmode)
    *oldmode = old;
  return TRUE;
}