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/* Cairo - a vector graphics library with display and print output
*
* Copyright © 2007 Chris Wilson
* Copyright © 2009 Intel Corporation
*
* This library is free software; you can redistribute it and/or
* modify it either under the terms of the GNU Lesser General Public
* License version 2.1 as published by the Free Software Foundation
* (the "LGPL") or, at your option, under the terms of the Mozilla
* Public License Version 1.1 (the "MPL"). If you do not alter this
* notice, a recipient may use your version of this file under either
* the MPL or the LGPL.
*
* You should have received a copy of the LGPL along with this library
* in the file COPYING-LGPL-2.1; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
* You should have received a copy of the MPL along with this library
* in the file COPYING-MPL-1.1
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
* OF ANY KIND, either express or implied. See the LGPL or the MPL for
* the specific language governing rights and limitations.
*
* The Original Code is the cairo graphics library.
*
* The Initial Developer of the Original Code is Red Hat, Inc.
*
* Contributors(s):
* Chris Wilson <chris@chris-wilson.co.uk>
*/
#include "cairoint.h"
#if CAIRO_HAS_XCB_SHM_FUNCTIONS
#include "cairo-xcb-private.h"
#include "cairo-list-inline.h"
#include "cairo-mempool-private.h"
#include <xcb/shm.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <errno.h>
#define CAIRO_MAX_SHM_MEMORY (16*1024*1024)
/* a simple buddy allocator for memory pools
* XXX fragmentation? use Doug Lea's malloc?
*/
typedef struct _cairo_xcb_shm_mem_block cairo_xcb_shm_mem_block_t;
typedef enum {
PENDING_WAIT,
PENDING_POLL
} shm_wait_type_t;
struct _cairo_xcb_shm_mem_pool {
int shmid;
uint32_t shmseg;
void *shm;
cairo_mempool_t mem;
cairo_list_t link;
};
static void
_cairo_xcb_shm_mem_pool_destroy (cairo_xcb_shm_mem_pool_t *pool)
{
cairo_list_del (&pool->link);
shmdt (pool->shm);
_cairo_mempool_fini (&pool->mem);
free (pool);
}
static void
_cairo_xcb_shm_info_finalize (cairo_xcb_shm_info_t *shm_info)
{
cairo_xcb_connection_t *connection = shm_info->connection;
assert (CAIRO_MUTEX_IS_LOCKED (connection->shm_mutex));
_cairo_mempool_free (&shm_info->pool->mem, shm_info->mem);
_cairo_freepool_free (&connection->shm_info_freelist, shm_info);
/* scan for old, unused pools - hold at least one in reserve */
if (! cairo_list_is_singular (&connection->shm_pools))
{
cairo_xcb_shm_mem_pool_t *pool, *next;
cairo_list_t head;
cairo_list_init (&head);
cairo_list_move (connection->shm_pools.next, &head);
cairo_list_foreach_entry_safe (pool, next, cairo_xcb_shm_mem_pool_t,
&connection->shm_pools, link)
{
if (pool->mem.free_bytes == pool->mem.max_bytes) {
_cairo_xcb_connection_shm_detach (connection, pool->shmseg);
_cairo_xcb_shm_mem_pool_destroy (pool);
}
}
cairo_list_move (head.next, &connection->shm_pools);
}
}
static void
_cairo_xcb_shm_process_pending (cairo_xcb_connection_t *connection, shm_wait_type_t wait)
{
cairo_xcb_shm_info_t *info, *next;
xcb_get_input_focus_reply_t *reply;
assert (CAIRO_MUTEX_IS_LOCKED (connection->shm_mutex));
cairo_list_foreach_entry_safe (info, next, cairo_xcb_shm_info_t,
&connection->shm_pending, pending)
{
switch (wait) {
case PENDING_WAIT:
reply = xcb_wait_for_reply (connection->xcb_connection,
info->sync.sequence, NULL);
break;
case PENDING_POLL:
if (! xcb_poll_for_reply (connection->xcb_connection,
info->sync.sequence,
(void **) &reply, NULL))
/* We cannot be sure the server finished with this image yet, so
* try again later. All other shm info are guaranteed to have a
* larger sequence number and thus don't have to be checked. */
return;
break;
default:
/* silence Clang static analyzer warning */
ASSERT_NOT_REACHED;
reply = NULL;
}
free (reply);
cairo_list_del (&info->pending);
_cairo_xcb_shm_info_finalize (info);
}
}
cairo_int_status_t
_cairo_xcb_connection_allocate_shm_info (cairo_xcb_connection_t *connection,
size_t size,
cairo_bool_t might_reuse,
cairo_xcb_shm_info_t **shm_info_out)
{
cairo_xcb_shm_info_t *shm_info;
cairo_xcb_shm_mem_pool_t *pool, *next;
size_t bytes, maxbits = 16, minbits = 8;
size_t shm_allocated = 0;
void *mem = NULL;
cairo_status_t status;
assert (connection->flags & CAIRO_XCB_HAS_SHM);
CAIRO_MUTEX_LOCK (connection->shm_mutex);
_cairo_xcb_shm_process_pending (connection, PENDING_POLL);
if (might_reuse) {
cairo_list_foreach_entry (shm_info, cairo_xcb_shm_info_t,
&connection->shm_pending, pending) {
if (shm_info->size >= size) {
cairo_list_del (&shm_info->pending);
CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
xcb_discard_reply (connection->xcb_connection, shm_info->sync.sequence);
shm_info->sync.sequence = XCB_NONE;
*shm_info_out = shm_info;
return CAIRO_STATUS_SUCCESS;
}
}
}
cairo_list_foreach_entry_safe (pool, next, cairo_xcb_shm_mem_pool_t,
&connection->shm_pools, link)
{
if (pool->mem.free_bytes > size) {
mem = _cairo_mempool_alloc (&pool->mem, size);
if (mem != NULL) {
/* keep the active pools towards the front */
cairo_list_move (&pool->link, &connection->shm_pools);
goto allocate_shm_info;
}
}
/* scan for old, unused pools */
if (pool->mem.free_bytes == pool->mem.max_bytes) {
_cairo_xcb_connection_shm_detach (connection,
pool->shmseg);
_cairo_xcb_shm_mem_pool_destroy (pool);
} else {
shm_allocated += pool->mem.max_bytes;
}
}
if (unlikely (shm_allocated >= CAIRO_MAX_SHM_MEMORY)) {
CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
return _cairo_error (CAIRO_STATUS_NO_MEMORY);
}
pool = malloc (sizeof (cairo_xcb_shm_mem_pool_t));
if (unlikely (pool == NULL)) {
CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
return _cairo_error (CAIRO_STATUS_NO_MEMORY);
}
bytes = 1 << maxbits;
while (bytes <= size)
bytes <<= 1, maxbits++;
bytes <<= 3;
do {
pool->shmid = shmget (IPC_PRIVATE, bytes, IPC_CREAT | 0600);
if (pool->shmid != -1)
break;
/* If the allocation failed because we asked for too much memory, we try
* again with a smaller request, as long as our allocation still fits. */
bytes >>= 1;
if (errno != EINVAL || bytes < size)
break;
} while (TRUE);
if (pool->shmid == -1) {
int err = errno;
if (! (err == EINVAL || err == ENOMEM))
connection->flags &= ~CAIRO_XCB_HAS_SHM;
free (pool);
CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
return CAIRO_INT_STATUS_UNSUPPORTED;
}
pool->shm = shmat (pool->shmid, NULL, 0);
if (unlikely (pool->shm == (char *) -1)) {
shmctl (pool->shmid, IPC_RMID, NULL);
free (pool);
CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
return _cairo_error (CAIRO_STATUS_NO_MEMORY);
}
status = _cairo_mempool_init (&pool->mem, pool->shm, bytes,
minbits, maxbits - minbits + 1);
if (unlikely (status)) {
shmdt (pool->shm);
free (pool);
CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
return status;
}
pool->shmseg = _cairo_xcb_connection_shm_attach (connection, pool->shmid, FALSE);
shmctl (pool->shmid, IPC_RMID, NULL);
cairo_list_add (&pool->link, &connection->shm_pools);
mem = _cairo_mempool_alloc (&pool->mem, size);
allocate_shm_info:
shm_info = _cairo_freepool_alloc (&connection->shm_info_freelist);
if (unlikely (shm_info == NULL)) {
_cairo_mempool_free (&pool->mem, mem);
CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
return _cairo_error (CAIRO_STATUS_NO_MEMORY);
}
shm_info->connection = connection;
shm_info->pool = pool;
shm_info->shm = pool->shmseg;
shm_info->size = size;
shm_info->offset = (char *) mem - (char *) pool->shm;
shm_info->mem = mem;
shm_info->sync.sequence = XCB_NONE;
/* scan for old, unused pools */
cairo_list_foreach_entry_safe (pool, next, cairo_xcb_shm_mem_pool_t,
&connection->shm_pools, link)
{
if (pool->mem.free_bytes == pool->mem.max_bytes) {
_cairo_xcb_connection_shm_detach (connection,
pool->shmseg);
_cairo_xcb_shm_mem_pool_destroy (pool);
}
}
CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
*shm_info_out = shm_info;
return CAIRO_STATUS_SUCCESS;
}
void
_cairo_xcb_shm_info_destroy (cairo_xcb_shm_info_t *shm_info)
{
cairo_xcb_connection_t *connection = shm_info->connection;
/* We can only return shm_info->mem to the allocator when we can be sure
* that the X server no longer reads from it. Since the X server processes
* requests in order, we send a GetInputFocus here.
* _cairo_xcb_shm_process_pending () will later check if the reply for that
* request was received and then actually mark this memory area as free. */
CAIRO_MUTEX_LOCK (connection->shm_mutex);
assert (shm_info->sync.sequence == XCB_NONE);
shm_info->sync = xcb_get_input_focus (connection->xcb_connection);
cairo_list_init (&shm_info->pending);
cairo_list_add_tail (&shm_info->pending, &connection->shm_pending);
CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
}
void
_cairo_xcb_connection_shm_mem_pools_flush (cairo_xcb_connection_t *connection)
{
CAIRO_MUTEX_LOCK (connection->shm_mutex);
_cairo_xcb_shm_process_pending (connection, PENDING_WAIT);
CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
}
void
_cairo_xcb_connection_shm_mem_pools_fini (cairo_xcb_connection_t *connection)
{
assert (cairo_list_is_empty (&connection->shm_pending));
while (! cairo_list_is_empty (&connection->shm_pools)) {
_cairo_xcb_shm_mem_pool_destroy (cairo_list_first_entry (&connection->shm_pools,
cairo_xcb_shm_mem_pool_t,
link));
}
}
#endif /* CAIRO_HAS_XCB_SHM_FUNCTIONS */