370 lines
11 KiB
C
370 lines
11 KiB
C
/* loader-loadlibrary.c -- dynamic linking for Win32
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Copyright (C) 1998, 1999, 2000, 2004, 2005, 2006,
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2007, 2008, 2010 Free Software Foundation, Inc.
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Written by Thomas Tanner, 1998
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NOTE: The canonical source of this file is maintained with the
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GNU Libtool package. Report bugs to bug-libtool@gnu.org.
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GNU Libltdl is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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As a special exception to the GNU Lesser General Public License,
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if you distribute this file as part of a program or library that
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is built using GNU Libtool, you may include this file under the
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same distribution terms that you use for the rest of that program.
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GNU Libltdl is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with GNU Libltdl; see the file COPYING.LIB. If not, a
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copy can be downloaded from http://www.gnu.org/licenses/lgpl.html,
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or obtained by writing to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "lt__private.h"
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#include "lt_dlloader.h"
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#if defined(__CYGWIN__)
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# include <sys/cygwin.h>
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#endif
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/* Use the preprocessor to rename non-static symbols to avoid namespace
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collisions when the loader code is statically linked into libltdl.
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Use the "<module_name>_LTX_" prefix so that the symbol addresses can
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be fetched from the preloaded symbol list by lt_dlsym(): */
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#define get_vtable loadlibrary_LTX_get_vtable
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LT_BEGIN_C_DECLS
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LT_SCOPE lt_dlvtable *get_vtable (lt_user_data loader_data);
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LT_END_C_DECLS
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/* Boilerplate code to set up the vtable for hooking this loader into
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libltdl's loader list: */
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static int vl_exit (lt_user_data loader_data);
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static lt_module vm_open (lt_user_data loader_data, const char *filename,
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lt_dladvise advise);
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static int vm_close (lt_user_data loader_data, lt_module module);
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static void * vm_sym (lt_user_data loader_data, lt_module module,
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const char *symbolname);
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static lt_dlinterface_id iface_id = 0;
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static lt_dlvtable *vtable = 0;
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/* Return the vtable for this loader, only the name and sym_prefix
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attributes (plus the virtual function implementations, obviously)
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change between loaders. */
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lt_dlvtable *
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get_vtable (lt_user_data loader_data)
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{
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if (!vtable)
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{
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vtable = (lt_dlvtable *) lt__zalloc (sizeof *vtable);
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iface_id = lt_dlinterface_register ("ltdl loadlibrary", NULL);
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}
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if (vtable && !vtable->name)
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{
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vtable->name = "lt_loadlibrary";
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vtable->module_open = vm_open;
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vtable->module_close = vm_close;
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vtable->find_sym = vm_sym;
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vtable->dlloader_exit = vl_exit;
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vtable->dlloader_data = loader_data;
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vtable->priority = LT_DLLOADER_APPEND;
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}
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if (vtable && (vtable->dlloader_data != loader_data))
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{
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LT__SETERROR (INIT_LOADER);
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return 0;
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}
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return vtable;
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}
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/* --- IMPLEMENTATION --- */
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#include <windows.h>
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#define LOCALFREE(mem) LT_STMT_START { \
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if (mem) { LocalFree ((void *)mem); mem = NULL; } } LT_STMT_END
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#define LOADLIB__SETERROR(errmsg) LT__SETERRORSTR (loadlibraryerror (errmsg))
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#define LOADLIB_SETERROR(errcode) LOADLIB__SETERROR (LT__STRERROR (errcode))
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static const char *loadlibraryerror (const char *default_errmsg);
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static DWORD WINAPI wrap_getthreaderrormode (void);
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static DWORD WINAPI fallback_getthreaderrormode (void);
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static BOOL WINAPI wrap_setthreaderrormode (DWORD mode, DWORD *oldmode);
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static BOOL WINAPI fallback_setthreaderrormode (DWORD mode, DWORD *oldmode);
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typedef DWORD (WINAPI getthreaderrormode_type) (void);
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typedef BOOL (WINAPI setthreaderrormode_type) (DWORD, DWORD *);
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static getthreaderrormode_type *getthreaderrormode = wrap_getthreaderrormode;
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static setthreaderrormode_type *setthreaderrormode = wrap_setthreaderrormode;
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static char *error_message = 0;
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/* A function called through the vtable when this loader is no
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longer needed by the application. */
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static int
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vl_exit (lt_user_data LT__UNUSED loader_data)
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{
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vtable = NULL;
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LOCALFREE (error_message);
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return 0;
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}
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/* A function called through the vtable to open a module with this
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loader. Returns an opaque representation of the newly opened
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module for processing with this loader's other vtable functions. */
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static lt_module
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vm_open (lt_user_data LT__UNUSED loader_data, const char *filename,
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lt_dladvise LT__UNUSED advise)
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{
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lt_module module = 0;
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char *ext;
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char wpath[MAX_PATH];
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size_t len;
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if (!filename)
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{
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/* Get the name of main module */
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*wpath = 0;
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GetModuleFileName (NULL, wpath, sizeof (wpath));
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filename = wpath;
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}
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else
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{
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len = LT_STRLEN (filename);
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if (len >= MAX_PATH)
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{
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LT__SETERROR (CANNOT_OPEN);
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return 0;
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}
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#if HAVE_DECL_CYGWIN_CONV_PATH
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if (cygwin_conv_path (CCP_POSIX_TO_WIN_A, filename, wpath, MAX_PATH))
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{
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LT__SETERROR (CANNOT_OPEN);
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return 0;
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}
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len = 0;
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#elif defined(__CYGWIN__)
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cygwin_conv_to_full_win32_path (filename, wpath);
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len = 0;
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#else
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strcpy(wpath, filename);
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#endif
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ext = strrchr (wpath, '.');
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if (!ext)
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{
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/* Append a `.' to stop Windows from adding an
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implicit `.dll' extension. */
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if (!len)
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len = strlen (wpath);
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if (len + 1 >= MAX_PATH)
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{
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LT__SETERROR (CANNOT_OPEN);
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return 0;
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}
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wpath[len] = '.';
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wpath[len+1] = '\0';
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}
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}
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{
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/* Silence dialog from LoadLibrary on some failures. */
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DWORD errormode = getthreaderrormode ();
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DWORD last_error;
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setthreaderrormode (errormode | SEM_FAILCRITICALERRORS, NULL);
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module = LoadLibrary (wpath);
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/* Restore the error mode. */
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last_error = GetLastError ();
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setthreaderrormode (errormode, NULL);
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SetLastError (last_error);
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}
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/* libltdl expects this function to fail if it is unable
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to physically load the library. Sadly, LoadLibrary
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will search the loaded libraries for a match and return
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one of them if the path search load fails.
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We check whether LoadLibrary is returning a handle to
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an already loaded module, and simulate failure if we
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find one. */
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{
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lt_dlhandle cur = 0;
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while ((cur = lt_dlhandle_iterate (iface_id, cur)))
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{
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if (!cur->module)
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{
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cur = 0;
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break;
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}
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if (cur->module == module)
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{
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break;
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}
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}
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if (!module)
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LOADLIB_SETERROR (CANNOT_OPEN);
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else if (cur)
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{
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LT__SETERROR (CANNOT_OPEN);
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module = 0;
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}
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}
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return module;
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}
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/* A function called through the vtable when a particular module
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should be unloaded. */
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static int
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vm_close (lt_user_data LT__UNUSED loader_data, lt_module module)
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{
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int errors = 0;
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if (FreeLibrary ((HMODULE) module) == 0)
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{
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LOADLIB_SETERROR (CANNOT_CLOSE);
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++errors;
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}
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return errors;
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}
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/* A function called through the vtable to get the address of
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a symbol loaded from a particular module. */
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static void *
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vm_sym (lt_user_data LT__UNUSED loader_data, lt_module module, const char *name)
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{
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void *address = (void *) GetProcAddress ((HMODULE) module, name);
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if (!address)
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{
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LOADLIB_SETERROR (SYMBOL_NOT_FOUND);
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}
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return address;
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}
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/* --- HELPER FUNCTIONS --- */
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/* Return the windows error message, or the passed in error message on
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failure. */
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static const char *
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loadlibraryerror (const char *default_errmsg)
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{
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size_t len;
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LOCALFREE (error_message);
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FormatMessageA (FORMAT_MESSAGE_ALLOCATE_BUFFER |
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FORMAT_MESSAGE_FROM_SYSTEM |
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FORMAT_MESSAGE_IGNORE_INSERTS,
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NULL,
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GetLastError (),
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0,
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(char *) &error_message,
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0, NULL);
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/* Remove trailing CRNL */
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len = LT_STRLEN (error_message);
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if (len && error_message[len - 1] == '\n')
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error_message[--len] = LT_EOS_CHAR;
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if (len && error_message[len - 1] == '\r')
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error_message[--len] = LT_EOS_CHAR;
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return len ? error_message : default_errmsg;
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}
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/* A function called through the getthreaderrormode variable which checks
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if the system supports GetThreadErrorMode (or GetErrorMode) and arranges
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for it or a fallback implementation to be called directly in the future.
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The selected version is then called. */
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static DWORD WINAPI
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wrap_getthreaderrormode (void)
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{
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HMODULE kernel32 = GetModuleHandleA ("kernel32.dll");
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getthreaderrormode
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= (getthreaderrormode_type *) GetProcAddress (kernel32,
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"GetThreadErrorMode");
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if (!getthreaderrormode)
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getthreaderrormode
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= (getthreaderrormode_type *) GetProcAddress (kernel32,
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"GetErrorMode");
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if (!getthreaderrormode)
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getthreaderrormode = fallback_getthreaderrormode;
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return getthreaderrormode ();
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}
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/* A function called through the getthreaderrormode variable for cases
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where the system does not support GetThreadErrorMode or GetErrorMode */
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static DWORD WINAPI
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fallback_getthreaderrormode (void)
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{
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/* Prior to Windows Vista, the only way to get the current error
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mode was to set a new one. In our case, we are setting a new
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error mode right after "getting" it while ignoring the error
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mode in effect when setting the new error mode, so that's
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fairly ok. */
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return (DWORD) SetErrorMode (SEM_FAILCRITICALERRORS);
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}
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/* A function called through the setthreaderrormode variable which checks
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if the system supports SetThreadErrorMode and arranges for it or a
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fallback implementation to be called directly in the future.
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The selected version is then called. */
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static BOOL WINAPI
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wrap_setthreaderrormode (DWORD mode, DWORD *oldmode)
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{
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HMODULE kernel32 = GetModuleHandleA ("kernel32.dll");
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setthreaderrormode
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= (setthreaderrormode_type *) GetProcAddress (kernel32,
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"SetThreadErrorMode");
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if (!setthreaderrormode)
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setthreaderrormode = fallback_setthreaderrormode;
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return setthreaderrormode (mode, oldmode);
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}
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/* A function called through the setthreaderrormode variable for cases
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where the system does not support SetThreadErrorMode. */
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static BOOL WINAPI
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fallback_setthreaderrormode (DWORD mode, DWORD *oldmode)
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{
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/* Prior to Windows 7, there was no way to set the thread local error
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mode, so set the process global error mode instead. */
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DWORD old = (DWORD) SetErrorMode (mode);
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if (oldmode)
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*oldmode = old;
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return TRUE;
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}
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