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This source file includes following definitions.
- get_vtable
- vl_exit
- vm_open
- vm_close
- vm_sym
- loadlibraryerror
- wrap_getthreaderrormode
- fallback_getthreaderrormode
- wrap_setthreaderrormode
- fallback_setthreaderrormode
1 /* loader-loadlibrary.c -- dynamic linking for Win32
2
3 Copyright (C) 1998, 1999, 2000, 2004, 2005, 2006,
4 2007, 2008, 2010 Free Software Foundation, Inc.
5 Written by Thomas Tanner, 1998
6
7 NOTE: The canonical source of this file is maintained with the
8 GNU Libtool package. Report bugs to bug-libtool@gnu.org.
9
10 GNU Libltdl is free software; you can redistribute it and/or
11 modify it under the terms of the GNU Lesser General Public
12 License as published by the Free Software Foundation; either
13 version 2 of the License, or (at your option) any later version.
14
15 As a special exception to the GNU Lesser General Public License,
16 if you distribute this file as part of a program or library that
17 is built using GNU Libtool, you may include this file under the
18 same distribution terms that you use for the rest of that program.
19
20 GNU Libltdl is distributed in the hope that it will be useful,
21 but WITHOUT ANY WARRANTY; without even the implied warranty of
22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 GNU Lesser General Public License for more details.
24
25 You should have received a copy of the GNU Lesser General Public
26 License along with GNU Libltdl; see the file COPYING.LIB. If not, a
27 copy can be downloaded from http://www.gnu.org/licenses/lgpl.html,
28 or obtained by writing to the Free Software Foundation, Inc.,
29 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
30 */
31
32 #include "lt__private.h"
33 #include "lt_dlloader.h"
34
35 #if defined(__CYGWIN__)
36 # include <sys/cygwin.h>
37 #endif
38
39 /* Use the preprocessor to rename non-static symbols to avoid namespace
40 collisions when the loader code is statically linked into libltdl.
41 Use the "<module_name>_LTX_" prefix so that the symbol addresses can
42 be fetched from the preloaded symbol list by lt_dlsym(): */
43 #define get_vtable loadlibrary_LTX_get_vtable
44
45 LT_BEGIN_C_DECLS
46 LT_SCOPE lt_dlvtable *get_vtable (lt_user_data loader_data);
47 LT_END_C_DECLS
48
49
50 /* Boilerplate code to set up the vtable for hooking this loader into
51 libltdl's loader list: */
52 static int vl_exit (lt_user_data loader_data);
53 static lt_module vm_open (lt_user_data loader_data, const char *filename,
54 lt_dladvise advise);
55 static int vm_close (lt_user_data loader_data, lt_module module);
56 static void * vm_sym (lt_user_data loader_data, lt_module module,
57 const char *symbolname);
58
59 static lt_dlinterface_id iface_id = 0;
60 static lt_dlvtable *vtable = 0;
61
62 /* Return the vtable for this loader, only the name and sym_prefix
63 attributes (plus the virtual function implementations, obviously)
64 change between loaders. */
65 lt_dlvtable *
66 get_vtable (lt_user_data loader_data)
67 {
68 if (!vtable)
69 {
70 vtable = (lt_dlvtable *) lt__zalloc (sizeof *vtable);
71 iface_id = lt_dlinterface_register ("ltdl loadlibrary", NULL);
72 }
73
74 if (vtable && !vtable->name)
75 {
76 vtable->name = "lt_loadlibrary";
77 vtable->module_open = vm_open;
78 vtable->module_close = vm_close;
79 vtable->find_sym = vm_sym;
80 vtable->dlloader_exit = vl_exit;
81 vtable->dlloader_data = loader_data;
82 vtable->priority = LT_DLLOADER_APPEND;
83 }
84
85 if (vtable && (vtable->dlloader_data != loader_data))
86 {
87 LT__SETERROR (INIT_LOADER);
88 return 0;
89 }
90
91 return vtable;
92 }
93
94
95
96 /* --- IMPLEMENTATION --- */
97
98
99 #include <windows.h>
100
101 #define LOCALFREE(mem) LT_STMT_START { \
102 if (mem) { LocalFree ((void *)mem); mem = NULL; } } LT_STMT_END
103 #define LOADLIB__SETERROR(errmsg) LT__SETERRORSTR (loadlibraryerror (errmsg))
104 #define LOADLIB_SETERROR(errcode) LOADLIB__SETERROR (LT__STRERROR (errcode))
105
106 static const char *loadlibraryerror (const char *default_errmsg);
107 static DWORD WINAPI wrap_getthreaderrormode (void);
108 static DWORD WINAPI fallback_getthreaderrormode (void);
109 static BOOL WINAPI wrap_setthreaderrormode (DWORD mode, DWORD *oldmode);
110 static BOOL WINAPI fallback_setthreaderrormode (DWORD mode, DWORD *oldmode);
111
112 typedef DWORD (WINAPI getthreaderrormode_type) (void);
113 typedef BOOL (WINAPI setthreaderrormode_type) (DWORD, DWORD *);
114
115 static getthreaderrormode_type *getthreaderrormode = wrap_getthreaderrormode;
116 static setthreaderrormode_type *setthreaderrormode = wrap_setthreaderrormode;
117 static char *error_message = 0;
118
119
120 /* A function called through the vtable when this loader is no
121 longer needed by the application. */
122 static int
123 vl_exit (lt_user_data LT__UNUSED loader_data)
124 {
125 vtable = NULL;
126 LOCALFREE (error_message);
127 return 0;
128 }
129
130 /* A function called through the vtable to open a module with this
131 loader. Returns an opaque representation of the newly opened
132 module for processing with this loader's other vtable functions. */
133 static lt_module
134 vm_open (lt_user_data LT__UNUSED loader_data, const char *filename,
135 lt_dladvise LT__UNUSED advise)
136 {
137 lt_module module = 0;
138 char *ext;
139 char wpath[MAX_PATH];
140 size_t len;
141
142 if (!filename)
143 {
144 /* Get the name of main module */
145 *wpath = 0;
146 GetModuleFileName (NULL, wpath, sizeof (wpath));
147 filename = wpath;
148 }
149 else
150 {
151 len = LT_STRLEN (filename);
152
153 if (len >= MAX_PATH)
154 {
155 LT__SETERROR (CANNOT_OPEN);
156 return 0;
157 }
158
159 #if HAVE_DECL_CYGWIN_CONV_PATH
160 if (cygwin_conv_path (CCP_POSIX_TO_WIN_A, filename, wpath, MAX_PATH))
161 {
162 LT__SETERROR (CANNOT_OPEN);
163 return 0;
164 }
165 len = 0;
166 #elif defined(__CYGWIN__)
167 cygwin_conv_to_full_win32_path (filename, wpath);
168 len = 0;
169 #else
170 strcpy(wpath, filename);
171 #endif
172
173 ext = strrchr (wpath, '.');
174 if (!ext)
175 {
176 /* Append a `.' to stop Windows from adding an
177 implicit `.dll' extension. */
178 if (!len)
179 len = strlen (wpath);
180
181 if (len + 1 >= MAX_PATH)
182 {
183 LT__SETERROR (CANNOT_OPEN);
184 return 0;
185 }
186
187 wpath[len] = '.';
188 wpath[len+1] = '\0';
189 }
190 }
191
192 {
193 /* Silence dialog from LoadLibrary on some failures. */
194 DWORD errormode = getthreaderrormode ();
195 DWORD last_error;
196
197 setthreaderrormode (errormode | SEM_FAILCRITICALERRORS, NULL);
198
199 module = LoadLibrary (wpath);
200
201 /* Restore the error mode. */
202 last_error = GetLastError ();
203 setthreaderrormode (errormode, NULL);
204 SetLastError (last_error);
205 }
206
207 /* libltdl expects this function to fail if it is unable
208 to physically load the library. Sadly, LoadLibrary
209 will search the loaded libraries for a match and return
210 one of them if the path search load fails.
211
212 We check whether LoadLibrary is returning a handle to
213 an already loaded module, and simulate failure if we
214 find one. */
215 {
216 lt_dlhandle cur = 0;
217
218 while ((cur = lt_dlhandle_iterate (iface_id, cur)))
219 {
220 if (!cur->module)
221 {
222 cur = 0;
223 break;
224 }
225
226 if (cur->module == module)
227 {
228 break;
229 }
230 }
231
232 if (!module)
233 LOADLIB_SETERROR (CANNOT_OPEN);
234 else if (cur)
235 {
236 LT__SETERROR (CANNOT_OPEN);
237 module = 0;
238 }
239 }
240
241 return module;
242 }
243
244
245 /* A function called through the vtable when a particular module
246 should be unloaded. */
247 static int
248 vm_close (lt_user_data LT__UNUSED loader_data, lt_module module)
249 {
250 int errors = 0;
251
252 if (FreeLibrary ((HMODULE) module) == 0)
253 {
254 LOADLIB_SETERROR (CANNOT_CLOSE);
255 ++errors;
256 }
257
258 return errors;
259 }
260
261
262 /* A function called through the vtable to get the address of
263 a symbol loaded from a particular module. */
264 static void *
265 vm_sym (lt_user_data LT__UNUSED loader_data, lt_module module, const char *name)
266 {
267 void *address = (void *) GetProcAddress ((HMODULE) module, name);
268
269 if (!address)
270 {
271 LOADLIB_SETERROR (SYMBOL_NOT_FOUND);
272 }
273
274 return address;
275 }
276
277
278
279 /* --- HELPER FUNCTIONS --- */
280
281
282 /* Return the windows error message, or the passed in error message on
283 failure. */
284 static const char *
285 loadlibraryerror (const char *default_errmsg)
286 {
287 size_t len;
288 LOCALFREE (error_message);
289
290 FormatMessageA (FORMAT_MESSAGE_ALLOCATE_BUFFER |
291 FORMAT_MESSAGE_FROM_SYSTEM |
292 FORMAT_MESSAGE_IGNORE_INSERTS,
293 NULL,
294 GetLastError (),
295 0,
296 (char *) &error_message,
297 0, NULL);
298
299 /* Remove trailing CRNL */
300 len = LT_STRLEN (error_message);
301 if (len && error_message[len - 1] == '\n')
302 error_message[--len] = LT_EOS_CHAR;
303 if (len && error_message[len - 1] == '\r')
304 error_message[--len] = LT_EOS_CHAR;
305
306 return len ? error_message : default_errmsg;
307 }
308
309 /* A function called through the getthreaderrormode variable which checks
310 if the system supports GetThreadErrorMode (or GetErrorMode) and arranges
311 for it or a fallback implementation to be called directly in the future.
312 The selected version is then called. */
313 static DWORD WINAPI
314 wrap_getthreaderrormode (void)
315 {
316 HMODULE kernel32 = GetModuleHandleA ("kernel32.dll");
317 getthreaderrormode
318 = (getthreaderrormode_type *) GetProcAddress (kernel32,
319 "GetThreadErrorMode");
320 if (!getthreaderrormode)
321 getthreaderrormode
322 = (getthreaderrormode_type *) GetProcAddress (kernel32,
323 "GetErrorMode");
324 if (!getthreaderrormode)
325 getthreaderrormode = fallback_getthreaderrormode;
326 return getthreaderrormode ();
327 }
328
329 /* A function called through the getthreaderrormode variable for cases
330 where the system does not support GetThreadErrorMode or GetErrorMode */
331 static DWORD WINAPI
332 fallback_getthreaderrormode (void)
333 {
334 /* Prior to Windows Vista, the only way to get the current error
335 mode was to set a new one. In our case, we are setting a new
336 error mode right after "getting" it while ignoring the error
337 mode in effect when setting the new error mode, so that's
338 fairly ok. */
339 return (DWORD) SetErrorMode (SEM_FAILCRITICALERRORS);
340 }
341
342 /* A function called through the setthreaderrormode variable which checks
343 if the system supports SetThreadErrorMode and arranges for it or a
344 fallback implementation to be called directly in the future.
345 The selected version is then called. */
346 static BOOL WINAPI
347 wrap_setthreaderrormode (DWORD mode, DWORD *oldmode)
348 {
349 HMODULE kernel32 = GetModuleHandleA ("kernel32.dll");
350 setthreaderrormode
351 = (setthreaderrormode_type *) GetProcAddress (kernel32,
352 "SetThreadErrorMode");
353 if (!setthreaderrormode)
354 setthreaderrormode = fallback_setthreaderrormode;
355 return setthreaderrormode (mode, oldmode);
356 }
357
358 /* A function called through the setthreaderrormode variable for cases
359 where the system does not support SetThreadErrorMode. */
360 static BOOL WINAPI
361 fallback_setthreaderrormode (DWORD mode, DWORD *oldmode)
362 {
363 /* Prior to Windows 7, there was no way to set the thread local error
364 mode, so set the process global error mode instead. */
365 DWORD old = (DWORD) SetErrorMode (mode);
366 if (oldmode)
367 *oldmode = old;
368 return TRUE;
369 }
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