/*
* Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
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*/
#define IOKIT_ENABLE_SHARED_PTR
#include <IOKit/IOSharedDataQueue.h>
#include <IOKit/IODataQueueShared.h>
#include <IOKit/IOLib.h>
#include <IOKit/IOMemoryDescriptor.h>
#include <libkern/c++/OSSharedPtr.h>
#include <vm/vm_kern_xnu.h>
#ifdef enqueue
#undef enqueue
#endif
#ifdef dequeue
#undef dequeue
#endif
#define super IODataQueue
OSDefineMetaClassAndStructors(IOSharedDataQueue, IODataQueue)
OSSharedPtr<IOSharedDataQueue>
IOSharedDataQueue::withCapacity(UInt32 size)
{
OSSharedPtr<IOSharedDataQueue> dataQueue = OSMakeShared<IOSharedDataQueue>();
if (dataQueue) {
if (!dataQueue->initWithCapacity(size)) {
return nullptr;
}
}
return dataQueue;
}
OSSharedPtr<IOSharedDataQueue>
IOSharedDataQueue::withEntries(UInt32 numEntries, UInt32 entrySize)
{
OSSharedPtr<IOSharedDataQueue> dataQueue = OSMakeShared<IOSharedDataQueue>();
if (dataQueue) {
if (!dataQueue->initWithEntries(numEntries, entrySize)) {
return nullptr;
}
}
return dataQueue;
}
Boolean
IOSharedDataQueue::initWithCapacity(UInt32 size)
{
IODataQueueAppendix * appendix;
vm_size_t allocSize;
kern_return_t kr;
if (!super::init()) {
return false;
}
_reserved = IOMallocType(ExpansionData);
if (!_reserved) {
return false;
}
if (size > UINT32_MAX - DATA_QUEUE_MEMORY_HEADER_SIZE - DATA_QUEUE_MEMORY_APPENDIX_SIZE) {
return false;
}
allocSize = round_page(size + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE);
if (allocSize < size) {
return false;
}
kr = kmem_alloc(kernel_map, (vm_offset_t *)&dataQueue, allocSize,
(kma_flags_t)(KMA_DATA | KMA_ZERO), IOMemoryTag(kernel_map));
if (kr != KERN_SUCCESS) {
return false;
}
dataQueue->queueSize = size;
// dataQueue->head = 0;
// dataQueue->tail = 0;
if (!setQueueSize(size)) {
return false;
}
appendix = (IODataQueueAppendix *)((UInt8 *)dataQueue + size + DATA_QUEUE_MEMORY_HEADER_SIZE);
appendix->version = 0;
if (!notifyMsg) {
notifyMsg = IOMallocType(mach_msg_header_t);
if (!notifyMsg) {
return false;
}
}
bzero(notifyMsg, sizeof(mach_msg_header_t));
setNotificationPort(MACH_PORT_NULL);
return true;
}
void
IOSharedDataQueue::free()
{
if (dataQueue) {
kmem_free(kernel_map, (vm_offset_t)dataQueue, round_page(getQueueSize() +
DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE));
dataQueue = NULL;
if (notifyMsg) {
IOFreeType(notifyMsg, mach_msg_header_t);
notifyMsg = NULL;
}
}
if (_reserved) {
IOFreeType(_reserved, ExpansionData);
_reserved = NULL;
}
super::free();
}
OSSharedPtr<IOMemoryDescriptor>
IOSharedDataQueue::getMemoryDescriptor()
{
OSSharedPtr<IOMemoryDescriptor> descriptor;
if (dataQueue != NULL) {
descriptor = IOMemoryDescriptor::withAddress(dataQueue, getQueueSize() + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE, kIODirectionOutIn);
}
return descriptor;
}
IODataQueueEntry *
IOSharedDataQueue::peek()
{
IODataQueueEntry *entry = NULL;
UInt32 headOffset;
UInt32 tailOffset;
if (!dataQueue) {
return NULL;
}
// Read head and tail with acquire barrier
// See rdar://problem/40780584 for an explanation of relaxed/acquire barriers
headOffset = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->head, __ATOMIC_RELAXED);
tailOffset = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->tail, __ATOMIC_ACQUIRE);
if (headOffset != tailOffset) {
volatile IODataQueueEntry * head = NULL;
UInt32 headSize = 0;
UInt32 headOffset = dataQueue->head;
UInt32 queueSize = getQueueSize();
if (headOffset > queueSize) {
return NULL;
}
head = (IODataQueueEntry *)((char *)dataQueue->queue + headOffset);
headSize = head->size;
// Check if there's enough room before the end of the queue for a header.
// If there is room, check if there's enough room to hold the header and
// the data.
if ((headOffset > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
(headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize) ||
(headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX - headSize) ||
(headOffset + headSize + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize)) {
// No room for the header or the data, wrap to the beginning of the queue.
// Note: wrapping even with the UINT32_MAX checks, as we have to support
// queueSize of UINT32_MAX
entry = dataQueue->queue;
} else {
entry = (IODataQueueEntry *)head;
}
}
return entry;
}
Boolean
IOSharedDataQueue::enqueue(void * data, UInt32 dataSize)
{
UInt32 head;
UInt32 tail;
UInt32 newTail;
const UInt32 entrySize = dataSize + DATA_QUEUE_ENTRY_HEADER_SIZE;
IODataQueueEntry * entry;
// Force a single read of head and tail
// See rdar://problem/40780584 for an explanation of relaxed/acquire barriers
tail = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->tail, __ATOMIC_RELAXED);
head = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->head, __ATOMIC_ACQUIRE);
// Check for overflow of entrySize
if (dataSize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) {
return false;
}
// Check for underflow of (getQueueSize() - tail)
if (getQueueSize() < tail || getQueueSize() < head) {
return false;
}
if (tail >= head) {
// Is there enough room at the end for the entry?
if ((entrySize <= UINT32_MAX - tail) &&
((tail + entrySize) <= getQueueSize())) {
entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
entry->size = dataSize;
__nochk_memcpy(&entry->data, data, dataSize);
// The tail can be out of bound when the size of the new entry
// exactly matches the available space at the end of the queue.
// The tail can range from 0 to dataQueue->queueSize inclusive.
newTail = tail + entrySize;
} else if (head > entrySize) { // Is there enough room at the beginning?
// Wrap around to the beginning, but do not allow the tail to catch
// up to the head.
dataQueue->queue->size = dataSize;
// We need to make sure that there is enough room to set the size before
// doing this. The user client checks for this and will look for the size
// at the beginning if there isn't room for it at the end.
if ((getQueueSize() - tail) >= DATA_QUEUE_ENTRY_HEADER_SIZE) {
((IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail))->size = dataSize;
}
__nochk_memcpy(&dataQueue->queue->data, data, dataSize);
newTail = entrySize;
} else {
return false; // queue is full
}
} else {
// Do not allow the tail to catch up to the head when the queue is full.
// That's why the comparison uses a '>' rather than '>='.
if ((head - tail) > entrySize) {
entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
entry->size = dataSize;
__nochk_memcpy(&entry->data, data, dataSize);
newTail = tail + entrySize;
} else {
return false; // queue is full
}
}
// Publish the data we just enqueued
__c11_atomic_store((_Atomic UInt32 *)&dataQueue->tail, newTail, __ATOMIC_RELEASE);
if (tail != head) {
//
// The memory barrier below paris with the one in ::dequeue
// so that either our store to the tail cannot be missed by
// the next dequeue attempt, or we will observe the dequeuer
// making the queue empty.
//
// Of course, if we already think the queue is empty,
// there's no point paying this extra cost.
//
__c11_atomic_thread_fence(__ATOMIC_SEQ_CST);
head = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->head, __ATOMIC_RELAXED);
}
if (tail == head) {
// Send notification (via mach message) that data is now available.
sendDataAvailableNotification();
}
return true;
}
Boolean
IOSharedDataQueue::dequeue(void *data, UInt32 *dataSize)
{
Boolean retVal = TRUE;
volatile IODataQueueEntry * entry = NULL;
UInt32 entrySize = 0;
UInt32 headOffset = 0;
UInt32 tailOffset = 0;
UInt32 newHeadOffset = 0;
if (!dataQueue || (data && !dataSize)) {
return false;
}
// Read head and tail with acquire barrier
// See rdar://problem/40780584 for an explanation of relaxed/acquire barriers
headOffset = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->head, __ATOMIC_RELAXED);
tailOffset = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->tail, __ATOMIC_ACQUIRE);
if (headOffset != tailOffset) {
volatile IODataQueueEntry * head = NULL;
UInt32 headSize = 0;
UInt32 queueSize = getQueueSize();
if (headOffset > queueSize) {
return false;
}
head = (IODataQueueEntry *)((char *)dataQueue->queue + headOffset);
headSize = head->size;
// we wrapped around to beginning, so read from there
// either there was not even room for the header
if ((headOffset > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
(headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize) ||
// or there was room for the header, but not for the data
(headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX - headSize) ||
(headOffset + headSize + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize)) {
// Note: we have to wrap to the beginning even with the UINT32_MAX checks
// because we have to support a queueSize of UINT32_MAX.
entry = dataQueue->queue;
entrySize = entry->size;
if ((entrySize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
(entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize)) {
return false;
}
newHeadOffset = entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE;
// else it is at the end
} else {
entry = head;
entrySize = entry->size;
if ((entrySize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
(entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX - headOffset) ||
(entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE + headOffset > queueSize)) {
return false;
}
newHeadOffset = headOffset + entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE;
}
} else {
// empty queue
return false;
}
if (data) {
if (entrySize > *dataSize) {
// not enough space
return false;
}
__nochk_memcpy(data, (void *)entry->data, entrySize);
*dataSize = entrySize;
}
__c11_atomic_store((_Atomic UInt32 *)&dataQueue->head, newHeadOffset, __ATOMIC_RELEASE);
if (newHeadOffset == tailOffset) {
//
// If we are making the queue empty, then we need to make sure
// that either the enqueuer notices, or we notice the enqueue
// that raced with our making of the queue empty.
//
__c11_atomic_thread_fence(__ATOMIC_SEQ_CST);
}
return retVal;
}
UInt32
IOSharedDataQueue::getQueueSize()
{
if (!_reserved) {
return 0;
}
return _reserved->queueSize;
}
Boolean
IOSharedDataQueue::setQueueSize(UInt32 size)
{
if (!_reserved) {
return false;
}
_reserved->queueSize = size;
return true;
}
OSMetaClassDefineReservedUnused(IOSharedDataQueue, 0);
OSMetaClassDefineReservedUnused(IOSharedDataQueue, 1);
OSMetaClassDefineReservedUnused(IOSharedDataQueue, 2);
OSMetaClassDefineReservedUnused(IOSharedDataQueue, 3);
OSMetaClassDefineReservedUnused(IOSharedDataQueue, 4);
OSMetaClassDefineReservedUnused(IOSharedDataQueue, 5);
OSMetaClassDefineReservedUnused(IOSharedDataQueue, 6);
OSMetaClassDefineReservedUnused(IOSharedDataQueue, 7);