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Surround initialisations with atomic critical section

Browse source 
Fixes the race condition when one thread uses cairo_mask_compositor_t
pointer returned by _cairo_image_mask_compositor_get, while another one
started but has not finished it's initialisation yet

Usage:
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
if (_cairo_atomic_init_once_enter(&once)) {
    /* Initialization code */
    _cairo_atomic_init_once_leave(&once);
}

https://bugs.freedesktop.org/show_bug.cgi?id=103037
This commit is contained in:
Mikhail Fludkov 2017-10-06 13:47:51 +02:00 • committed by Adrian Johnson
parent 79e0e25e44
commit 90104809b0
10 changed files with 87 additions and 15 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

33
src/cairo-atomic-private.h
View file

@ -45,6 +45,8 @@
#include "config.h"
#endif
#include <assert.h>
/* The autoconf on OpenBSD 4.5 produces the malformed constant name
* SIZEOF_VOID__ rather than SIZEOF_VOID_P. Work around that here. */
#if !defined(SIZEOF_VOID_P) && defined(SIZEOF_VOID__)
@ -393,6 +395,37 @@ _cairo_atomic_ptr_cmpxchg_return_old_fallback(void **x, void *oldv, void *newv)
(void) ret__; \
} while (0)
typedef cairo_atomic_int_t cairo_atomic_once_t;
#define CAIRO_ATOMIC_ONCE_UNINITIALIZED (0)
#define CAIRO_ATOMIC_ONCE_INITIALIZING (1)
#define CAIRO_ATOMIC_ONCE_INITIALIZED (2)
#define CAIRO_ATOMIC_ONCE_INIT CAIRO_ATOMIC_ONCE_UNINITIALIZED
static cairo_always_inline cairo_bool_t
_cairo_atomic_init_once_enter(cairo_atomic_once_t *once)
{
if (likely(_cairo_atomic_int_get(once) == CAIRO_ATOMIC_ONCE_INITIALIZED))
return 0;
if (_cairo_atomic_int_cmpxchg(once,
CAIRO_ATOMIC_ONCE_UNINITIALIZED,
CAIRO_ATOMIC_ONCE_INITIALIZING))
return 1;
while (_cairo_atomic_int_get(once) != CAIRO_ATOMIC_ONCE_INITIALIZED) {}
return 0;
}
static cairo_always_inline void
_cairo_atomic_init_once_leave(cairo_atomic_once_t *once)
{
if (unlikely(!_cairo_atomic_int_cmpxchg(once,
CAIRO_ATOMIC_ONCE_INITIALIZING,
CAIRO_ATOMIC_ONCE_INITIALIZED)))
assert (0 && "incorrect use of _cairo_atomic_init_once API (once != CAIRO_ATOMIC_ONCE_INITIALIZING)");
}
CAIRO_END_DECLS
#endif

5
src/cairo-gl-msaa-compositor.c
View file

@ -944,10 +944,13 @@ _cairo_gl_msaa_compositor_init (cairo_compositor_t *compositor,
const cairo_compositor_t *
_cairo_gl_msaa_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_compositor_t compositor;
if (compositor.delegate == NULL)
if (_cairo_atomic_init_once_enter(&once)) {
_cairo_gl_msaa_compositor_init (&compositor,
_cairo_gl_span_compositor_get ());
_cairo_atomic_init_once_leave(&once);
}
return &compositor;
}

5
src/cairo-gl-spans-compositor.c
View file

@ -528,10 +528,11 @@ _cairo_gl_span_renderer_fini (cairo_abstract_span_renderer_t *_r,
const cairo_compositor_t *
_cairo_gl_span_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_spans_compositor_t spans;
static cairo_compositor_t shape;
if (spans.base.delegate == NULL) {
if (_cairo_atomic_init_once_enter(&once)) {
/* The fallback to traps here is essentially just for glyphs... */
_cairo_shape_mask_compositor_init (&shape,
_cairo_gl_traps_compositor_get());
@ -547,6 +548,8 @@ _cairo_gl_span_compositor_get (void)
//spans.check_span_renderer = check_span_renderer;
spans.renderer_init = _cairo_gl_span_renderer_init;
spans.renderer_fini = _cairo_gl_span_renderer_fini;
_cairo_atomic_init_once_leave(&once);
}
return &spans.base;

5
src/cairo-gl-traps-compositor.c
View file

@ -500,9 +500,10 @@ check_composite (const cairo_composite_rectangles_t *extents)
const cairo_compositor_t *
_cairo_gl_traps_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_traps_compositor_t compositor;
if (compositor.base.delegate == NULL) {
if (_cairo_atomic_init_once_enter(&once)) {
_cairo_traps_compositor_init (&compositor, &_cairo_fallback_compositor);
compositor.acquire = acquire;
compositor.release = release;
@ -522,6 +523,8 @@ _cairo_gl_traps_compositor_get (void)
compositor.composite_tristrip = composite_tristrip;
compositor.check_composite_glyphs = _cairo_gl_check_composite_glyphs;
compositor.composite_glyphs = _cairo_gl_composite_glyphs;
_cairo_atomic_init_once_leave(&once);
}
return &compositor.base;

19
src/cairo-image-compositor.c
View file

@ -1244,11 +1244,12 @@ check_composite (const cairo_composite_rectangles_t *extents)
const cairo_compositor_t *
_cairo_image_traps_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_traps_compositor_t compositor;
if (compositor.base.delegate == NULL) {
_cairo_traps_compositor_init (&compositor,
&__cairo_no_compositor);
if (_cairo_atomic_init_once_enter(&once)) {
_cairo_traps_compositor_init(&compositor,
&__cairo_no_compositor);
compositor.acquire = acquire;
compositor.release = release;
compositor.set_clip_region = set_clip_region;
@ -1269,6 +1270,8 @@ _cairo_image_traps_compositor_get (void)
#endif
compositor.check_composite_glyphs = check_composite_glyphs;
compositor.composite_glyphs = composite_glyphs;
_cairo_atomic_init_once_leave(&once);
}
return &compositor.base;
@ -1277,9 +1280,10 @@ _cairo_image_traps_compositor_get (void)
const cairo_compositor_t *
_cairo_image_mask_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_mask_compositor_t compositor;
if (compositor.base.delegate == NULL) {
if (_cairo_atomic_init_once_enter(&once)) {
_cairo_mask_compositor_init (&compositor,
_cairo_image_traps_compositor_get ());
compositor.acquire = acquire;
@ -1296,6 +1300,8 @@ _cairo_image_mask_compositor_get (void)
compositor.composite_boxes = composite_boxes;
compositor.check_composite_glyphs = check_composite_glyphs;
compositor.composite_glyphs = composite_glyphs;
_cairo_atomic_init_once_leave(&once);
}
return &compositor.base;
@ -3105,10 +3111,11 @@ span_renderer_fini (cairo_abstract_span_renderer_t *_r,
const cairo_compositor_t *
_cairo_image_spans_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_spans_compositor_t spans;
static cairo_compositor_t shape;
if (spans.base.delegate == NULL) {
if (_cairo_atomic_init_once_enter(&once)) {
_cairo_shape_mask_compositor_init (&shape,
_cairo_image_traps_compositor_get());
shape.glyphs = NULL;
@ -3131,6 +3138,8 @@ _cairo_image_spans_compositor_get (void)
//spans.check_span_renderer = check_span_renderer;
spans.renderer_init = span_renderer_init;
spans.renderer_fini = span_renderer_fini;
_cairo_atomic_init_once_leave(&once);
}
return &spans.base;

5
src/cairo-image-mask-compositor.c
View file

@ -387,9 +387,10 @@ composite_boxes (void *_dst,
const cairo_compositor_t *
_cairo_image_mask_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_mask_compositor_t compositor;
if (compositor.base.delegate == NULL) {
if (_cairo_atomic_init_once_enter(&once)) {
_cairo_mask_compositor_init (&compositor,
_cairo_image_traps_compositor_get ());
compositor.acquire = acquire;
@ -405,6 +406,8 @@ _cairo_image_mask_compositor_get (void)
compositor.composite = composite;
//compositor.check_composite_boxes = check_composite_boxes;
compositor.composite_boxes = composite_boxes;
_cairo_atomic_init_once_leave(&once);
}
return &compositor.base;

5
src/cairo-xlib-core-compositor.c
View file

@ -632,9 +632,10 @@ _cairo_xlib_core_compositor_fill (const cairo_compositor_t *compositor,
const cairo_compositor_t *
_cairo_xlib_core_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_compositor_t compositor;
if (compositor.delegate == NULL) {
if (_cairo_atomic_init_once_enter(&once)) {
compositor.delegate = _cairo_xlib_fallback_compositor_get ();
compositor.paint = _cairo_xlib_core_compositor_paint;
@ -642,6 +643,8 @@ _cairo_xlib_core_compositor_get (void)
compositor.fill = _cairo_xlib_core_compositor_fill;
compositor.stroke = _cairo_xlib_core_compositor_stroke;
compositor.glyphs = NULL; /* XXX PolyGlyph? */
_cairo_atomic_init_once_leave(&once);
}
return &compositor;

10
src/cairo-xlib-render-compositor.c
View file

@ -1725,9 +1725,10 @@ composite_glyphs (void *surface,
const cairo_compositor_t *
_cairo_xlib_mask_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_mask_compositor_t compositor;
if (compositor.base.delegate == NULL) {
if (_cairo_atomic_init_once_enter(&once)) {
_cairo_mask_compositor_init (&compositor,
_cairo_xlib_fallback_compositor_get ());
@ -1745,6 +1746,8 @@ _cairo_xlib_mask_compositor_get (void)
compositor.composite_boxes = composite_boxes;
compositor.check_composite_glyphs = check_composite_glyphs;
compositor.composite_glyphs = composite_glyphs;
_cairo_atomic_init_once_leave(&once);
}
return &compositor.base;
@ -1973,9 +1976,10 @@ composite_tristrip (void *abstract_dst,
const cairo_compositor_t *
_cairo_xlib_traps_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_traps_compositor_t compositor;
if (compositor.base.delegate == NULL) {
if (_cairo_atomic_init_once_enter(&once)) {
_cairo_traps_compositor_init (&compositor,
_cairo_xlib_mask_compositor_get ());
@ -1997,6 +2001,8 @@ _cairo_xlib_traps_compositor_get (void)
compositor.composite_tristrip = composite_tristrip;
compositor.check_composite_glyphs = check_composite_glyphs;
compositor.composite_glyphs = composite_glyphs;
_cairo_atomic_init_once_leave(&once);
}
return &compositor.base;

10
src/test-null-compositor-surface.c
View file

@ -404,9 +404,10 @@ check_composite (const cairo_composite_rectangles_t *extents)
static const cairo_compositor_t *
no_traps_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_traps_compositor_t compositor;
if (compositor.base.delegate == NULL) {
if (_cairo_atomic_init_once_enter(&once)) {
_cairo_traps_compositor_init (&compositor,
no_fallback_compositor_get ());
@ -426,6 +427,8 @@ no_traps_compositor_get (void)
compositor.composite_traps = composite_traps;
compositor.check_composite_glyphs = check_composite_glyphs;
compositor.composite_glyphs = composite_glyphs;
_cairo_atomic_init_once_leave(&once);
}
return &compositor.base;
@ -434,9 +437,10 @@ no_traps_compositor_get (void)
static const cairo_compositor_t *
no_spans_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_spans_compositor_t compositor;
if (compositor.base.delegate == NULL) {
if (_cairo_atomic_init_once_enter(&once)) {
_cairo_spans_compositor_init (&compositor,
no_traps_compositor_get());
@ -448,6 +452,8 @@ no_spans_compositor_get (void)
//compositor.check_span_renderer = check_span_renderer;
compositor.renderer_init = span_renderer_init;
compositor.renderer_fini = span_renderer_fini;
_cairo_atomic_init_once_leave(&once);
}
return &compositor.base;

5
src/win32/cairo-win32-gdi-compositor.c
View file

@ -634,9 +634,10 @@ _cairo_win32_gdi_compositor_glyphs (const cairo_compositor_t *compositor,
const cairo_compositor_t *
_cairo_win32_gdi_compositor_get (void)
{
static cairo_atomic_once_t once = CAIRO_ATOMIC_ONCE_INIT;
static cairo_compositor_t compositor;
if (compositor.delegate == NULL) {
if (_cairo_atomic_init_once_enter(&once)) {
compositor.delegate = &_cairo_fallback_compositor;
compositor.paint = _cairo_win32_gdi_compositor_paint;
@ -644,6 +645,8 @@ _cairo_win32_gdi_compositor_get (void)
compositor.fill = _cairo_win32_gdi_compositor_fill;
compositor.stroke = _cairo_win32_gdi_compositor_stroke;
compositor.glyphs = _cairo_win32_gdi_compositor_glyphs;
_cairo_atomic_init_once_leave(&once);
}
return &compositor;