libltdl/loaders/loadlibrary.c

/* loader-loadlibrary.c --  dynamic linking for Win32

   Copyright (C) 1998-2000, 2004-2008, 2010-2014 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 that 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 that 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;
}
Revision:	4901
Committed:	Sat Nov 22 18:31:53 2014 UTC (11 years, 8 months ago) by michael
Content type:	text/x-csrc
File size:	10836 byte(s)
Log Message:	- autoreconf
#	Content
1	/* loader-loadlibrary.c -- dynamic linking for Win32
2
3	Copyright (C) 1998-2000, 2004-2008, 2010-2014 Free Software
4	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 that 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 that 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	}