glib/glib/grcboxprivate.h
Emmanuele Bassi 87f0a5a219 Align the reference counted allocations
We need stronger alignment guarantees for the memory allocations done
through g_rc_box_alloc_full(): while the passed block size may be
aligned, we're not aligning the private data size; this means the
overall allocation may become unaligned, and this could raise issues
when we use the private data size as an offset to access the reference
count.

Fixes: #1581
2018-12-18 11:18:43 +00:00

72 lines
1.9 KiB
C

/* grcboxprivate.h: Reference counted data
*
* Copyright 2018 Emmanuele Bassi
*
* 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/>.
*/
#pragma once
#include "gtypes.h"
#include "grcbox.h"
G_BEGIN_DECLS
typedef struct {
grefcount ref_count;
gsize mem_size;
gsize private_offset;
#ifndef G_DISABLE_ASSERT
/* A "magic" number, used to perform additional integrity
* checks on the allocated data
*/
guint32 magic;
#endif
} GRcBox;
typedef struct {
gatomicrefcount ref_count;
gsize mem_size;
gsize private_offset;
#ifndef G_DISABLE_ASSERT
guint32 magic;
#endif
} GArcBox;
#define G_BOX_MAGIC 0x44ae2bf0
/* Keep the two refcounted boxes identical in size */
G_STATIC_ASSERT (sizeof (GRcBox) == sizeof (GArcBox));
/* This is the default alignment we use when allocating the
* refcounted memory blocks; it's similar to the alignment
* guaranteed by the malloc() in GNU's libc and by the GSlice
* allocator
*/
#define STRUCT_ALIGNMENT (2 * sizeof (gsize))
#define G_RC_BOX_SIZE sizeof (GRcBox)
#define G_ARC_BOX_SIZE sizeof (GArcBox)
gpointer g_rc_box_alloc_full (gsize block_size,
gsize alignment,
gboolean atomic,
gboolean clear);
G_END_DECLS