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user32: Load libpng in DllMain. 

libpng is currently loaded on the first attempt to access a PNG icon
or cursor. That creates a race condition that can deadlock the loader
in certain circumstances if LoadIcon or LoadCursor is called while the
loader lock is held, e.g. from a DllMain.

Signed-off-by: Tim Clem <tclem@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>
This commit is contained in:
Tim Clem 2021-08-26 13:01:19 -07:00 committed by Alexandre Julliard
parent dd37c3c4a0
commit b4333216a7
4 changed files with 11 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
dlls/user32/cursoricon.c
View File

@ -111,21 +111,6 @@ static int get_display_bpp(void)
return ret;
}
static INIT_ONCE init_once = INIT_ONCE_STATIC_INIT;
static const struct png_funcs *png_funcs;
static BOOL WINAPI load_libpng( INIT_ONCE *once, void *param, void **context )
{
__wine_init_unix_lib( user32_module, DLL_PROCESS_ATTACH, NULL, &png_funcs );
return TRUE;
}
static BOOL have_libpng(void)
{
return InitOnceExecuteOnce( &init_once, load_libpng, NULL, NULL ) && png_funcs;
}
static HICON alloc_icon_handle( BOOL is_ani, UINT num_steps )
{
struct cursoricon_object *obj;
@ -571,7 +556,7 @@ static BOOL CURSORICON_GetResIconEntry( LPCVOID dir, DWORD size, int n,
*width = icon->bWidth;
*height = icon->bHeight;
*bits = resdir->idEntries[n].wBitCount;
if (!*width && !*height && have_libpng()) *width = *height = 256;
if (!*width && !*height && png_funcs) *width = *height = 256;
return TRUE;
}
@ -704,7 +689,7 @@ static BOOL CURSORICON_GetFileEntry( LPCVOID dir, DWORD size, int n,
if (info->biSize == PNG_SIGN)
{
if (have_libpng()) return png_funcs->get_png_info(info, size, width, height, bits);
if (png_funcs) return png_funcs->get_png_info(info, size, width, height, bits);
*width = *height = *bits = 0;
return TRUE;
}
@ -858,7 +843,7 @@ static HICON create_icon_from_bmi( const BITMAPINFO *bmi, DWORD maxsize, HMODULE
{
BITMAPINFO *bmi_png;
if (!have_libpng()) return 0;
if (!png_funcs) return 0;
bmi_png = png_funcs->load_png( (const char *)bmi, &maxsize );
if (bmi_png)
{

4
dlls/user32/png.c
View File

@ -293,7 +293,7 @@ static BITMAPINFO * CDECL load_png(const char *png_data, DWORD *size)
return info;
}
static const struct png_funcs png_funcs =
static const struct png_funcs funcs =
{
get_png_info,
load_png
@ -335,7 +335,7 @@ NTSTATUS CDECL __wine_init_unix_lib( HMODULE module, DWORD reason, const void *p
LOAD_FUNCPTR(png_set_read_fn);
#undef LOAD_FUNCPTR
*(const struct png_funcs **)ptr_out = &png_funcs;
*(const struct png_funcs **)ptr_out = &funcs;
return STATUS_SUCCESS;
}

3
dlls/user32/user_main.c
View File

@ -52,6 +52,8 @@ static HPALETTE hPrimaryPalette;
static DWORD exiting_thread_id;
const struct png_funcs *png_funcs = NULL;
extern void WDML_NotifyThreadDetach(void);
#ifdef __MINGW32__
@ -332,6 +334,7 @@ static BOOL process_attach(void)
palette_init();
keyboard_init();
__wine_init_unix_lib( user32_module, DLL_PROCESS_ATTACH, NULL, &png_funcs );
return TRUE;
}

3
dlls/user32/user_private.h
View File

@ -380,6 +380,9 @@ struct png_funcs
BITMAPINFO * (CDECL *load_png)(const char *png_data, DWORD *size);
};
/* May be NULL if libpng cannot be loaded. */
extern const struct png_funcs *png_funcs DECLSPEC_HIDDEN;
/* Mingw's assert() imports MessageBoxA and gets confused by user32 exporting it */
#ifdef __MINGW32__
#undef assert