glib/gmodule/gmodule-win32.c
Christoph Reiter 6a903ff6d7 Fix g_module_symbol() under Windows sometimes not succeeding
g_module_symbol() internally calls CreateToolhelp32Snapshot() which
in some circumstances returns ERROR_BAD_LENGTH and according to the docs
should lead to CreateToolhelp32Snapshot() being retried by the caller.

This retry logic was missing and for example led to g_module_symbol()
not succeeding if another thread happened to call the wrong function
at the wrong time.

This got noticed in the g-i build of gtk4 where g-i would call g_module_symbol()
on all gtk4 _get_type symbols and while inspecting the properties gtk4 would
spawn a thread calling SHGetSpecialFolderLocation() somewhere down the line.
During the call to SHGetSpecialFolderLocation() CreateToolhelp32Snapshot() would
return with ERROR_BAD_LENGTH for a short period of time and make g_module_symbol()
fail, which lead to "Invalid GType function" errors in g-i.

Fixes https://gitlab.gnome.org/GNOME/gtk/-/issues/3213
2020-09-30 09:57:40 +02:00

233 lines
5.9 KiB
C

/* GMODULE - GLIB wrapper code for dynamic module loading
* Copyright (C) 1998, 2000 Tim Janik
*
* Win32 GMODULE implementation
* Copyright (C) 1998 Tor Lillqvist
*
* This library 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 2.1 of the License, or (at your option) any later version.
*
* This library 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 this library; if not, see <http://www.gnu.org/licenses/>.
*/
/*
* Modified by the GLib Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GLib Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GLib at ftp://ftp.gtk.org/pub/gtk/.
*/
/*
* MT safe
*/
#include "config.h"
#include <stdio.h>
#include <windows.h>
#include <tlhelp32.h>
#ifdef G_WITH_CYGWIN
#include <sys/cygwin.h>
#endif
static void G_GNUC_PRINTF (1, 2)
set_error (const gchar *format,
...)
{
gchar *error;
gchar *detail;
gchar *message;
va_list args;
error = g_win32_error_message (GetLastError ());
va_start (args, format);
detail = g_strdup_vprintf (format, args);
va_end (args);
message = g_strconcat (detail, error, NULL);
g_module_set_error (message);
g_free (message);
g_free (detail);
g_free (error);
}
/* --- functions --- */
static gpointer
_g_module_open (const gchar *file_name,
gboolean bind_lazy,
gboolean bind_local)
{
HINSTANCE handle;
wchar_t *wfilename;
DWORD old_mode;
BOOL success;
#ifdef G_WITH_CYGWIN
gchar tmp[MAX_PATH];
cygwin_conv_to_win32_path(file_name, tmp);
file_name = tmp;
#endif
wfilename = g_utf8_to_utf16 (file_name, -1, NULL, NULL, NULL);
/* suppress error dialog */
success = SetThreadErrorMode (SEM_NOOPENFILEERRORBOX | SEM_FAILCRITICALERRORS, &old_mode);
if (!success)
set_error ("");
/* When building for UWP, load app asset DLLs instead of filesystem DLLs.
* Needs MSVC, Windows 8 and newer, and is only usable from apps. */
#if _WIN32_WINNT >= 0x0602 && defined(G_WINAPI_ONLY_APP)
handle = LoadPackagedLibrary (wfilename, 0);
#else
handle = LoadLibraryW (wfilename);
#endif
if (success)
SetThreadErrorMode (old_mode, NULL);
g_free (wfilename);
if (!handle)
set_error ("'%s': ", file_name);
return handle;
}
static gint dummy;
static gpointer null_module_handle = &dummy;
static gpointer
_g_module_self (void)
{
return null_module_handle;
}
static void
_g_module_close (gpointer handle)
{
if (handle != null_module_handle)
if (!FreeLibrary (handle))
set_error ("");
}
static gpointer
find_in_any_module_using_toolhelp (const gchar *symbol_name)
{
HANDLE snapshot;
MODULEENTRY32 me32;
gpointer p = NULL;
/* Under UWP, Module32Next and Module32First are not available since we're
* not allowed to search in the address space of arbitrary loaded DLLs */
#if !defined(G_WINAPI_ONLY_APP)
/* https://docs.microsoft.com/en-us/windows/win32/api/tlhelp32/nf-tlhelp32-createtoolhelp32snapshot#remarks
* If the function fails with ERROR_BAD_LENGTH, retry the function until it succeeds. */
while (TRUE)
{
snapshot = CreateToolhelp32Snapshot (TH32CS_SNAPMODULE, 0);
if (snapshot == INVALID_HANDLE_VALUE && GetLastError () == ERROR_BAD_LENGTH)
{
g_thread_yield ();
continue;
}
break;
}
if (snapshot == INVALID_HANDLE_VALUE)
return NULL;
me32.dwSize = sizeof (me32);
p = NULL;
if (Module32First (snapshot, &me32))
{
do {
if ((p = GetProcAddress (me32.hModule, symbol_name)) != NULL)
break;
} while (Module32Next (snapshot, &me32));
}
CloseHandle (snapshot);
#endif
return p;
}
static gpointer
find_in_any_module (const gchar *symbol_name)
{
gpointer result;
if ((result = find_in_any_module_using_toolhelp (symbol_name)) == NULL)
return NULL;
else
return result;
}
static gpointer
_g_module_symbol (gpointer handle,
const gchar *symbol_name)
{
gpointer p;
if (handle == null_module_handle)
{
if ((p = GetProcAddress (GetModuleHandle (NULL), symbol_name)) == NULL)
p = find_in_any_module (symbol_name);
}
else
p = GetProcAddress (handle, symbol_name);
if (!p)
set_error ("");
return p;
}
static gchar*
_g_module_build_path (const gchar *directory,
const gchar *module_name)
{
gint k;
k = strlen (module_name);
if (directory && *directory)
if (k > 4 && g_ascii_strcasecmp (module_name + k - 4, ".dll") == 0)
return g_strconcat (directory, G_DIR_SEPARATOR_S, module_name, NULL);
#ifdef G_WITH_CYGWIN
else if (strncmp (module_name, "lib", 3) == 0 || strncmp (module_name, "cyg", 3) == 0)
return g_strconcat (directory, G_DIR_SEPARATOR_S, module_name, ".dll", NULL);
else
return g_strconcat (directory, G_DIR_SEPARATOR_S, "cyg", module_name, ".dll", NULL);
#else
else if (strncmp (module_name, "lib", 3) == 0)
return g_strconcat (directory, G_DIR_SEPARATOR_S, module_name, ".dll", NULL);
else
return g_strconcat (directory, G_DIR_SEPARATOR_S, "lib", module_name, ".dll", NULL);
#endif
else if (k > 4 && g_ascii_strcasecmp (module_name + k - 4, ".dll") == 0)
return g_strdup (module_name);
#ifdef G_WITH_CYGWIN
else if (strncmp (module_name, "lib", 3) == 0 || strncmp (module_name, "cyg", 3) == 0)
return g_strconcat (module_name, ".dll", NULL);
else
return g_strconcat ("cyg", module_name, ".dll", NULL);
#else
else if (strncmp (module_name, "lib", 3) == 0)
return g_strconcat (module_name, ".dll", NULL);
else
return g_strconcat ("lib", module_name, ".dll", NULL);
#endif
}