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--- xnu/xnu-201/iokit/Kernel/IODataQueue.cpp
+++ xnu/xnu-4903.241.1/iokit/Kernel/IODataQueue.cpp
@@ -1,29 +1,47 @@
/*
* Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
*
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License"). You may not use this file except in compliance with the
- * License. Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * 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.
*
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * 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 OR NON-INFRINGEMENT. Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
*
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
+#define DISABLE_DATAQUEUE_WARNING
+
#include <IOKit/IODataQueue.h>
+
+#undef DISABLE_DATAQUEUE_WARNING
+
#include <IOKit/IODataQueueShared.h>
#include <IOKit/IOLib.h>
#include <IOKit/IOMemoryDescriptor.h>
+#include <libkern/OSAtomic.h>
+
+struct IODataQueueInternal
+{
+ mach_msg_header_t msg;
+ UInt32 queueSize;
+};
#ifdef enqueue
#undef enqueue
@@ -67,31 +85,68 @@
Boolean IODataQueue::initWithCapacity(UInt32 size)
{
+ vm_size_t allocSize = 0;
+
if (!super::init()) {
return false;
}
- dataQueue = (IODataQueueMemory *)IOMallocAligned(round_page(size + DATA_QUEUE_MEMORY_HEADER_SIZE), PAGE_SIZE);
+ if (size > UINT32_MAX - DATA_QUEUE_MEMORY_HEADER_SIZE) {
+ return false;
+ }
+
+ allocSize = round_page(size + DATA_QUEUE_MEMORY_HEADER_SIZE);
+
+ if (allocSize < size) {
+ return false;
+ }
+
+ assert(!notifyMsg);
+ notifyMsg = IONew(IODataQueueInternal, 1);
+ if (!notifyMsg) {
+ return false;
+ }
+ bzero(notifyMsg, sizeof(IODataQueueInternal));
+ ((IODataQueueInternal *)notifyMsg)->queueSize = size;
+
+ dataQueue = (IODataQueueMemory *)IOMallocAligned(allocSize, PAGE_SIZE);
if (dataQueue == 0) {
return false;
}
-
- dataQueue->queueSize = size;
- dataQueue->head = 0;
- dataQueue->tail = 0;
+ bzero(dataQueue, allocSize);
+
+ dataQueue->queueSize = size;
+// dataQueue->head = 0;
+// dataQueue->tail = 0;
return true;
}
Boolean IODataQueue::initWithEntries(UInt32 numEntries, UInt32 entrySize)
{
+ // Checking overflow for (numEntries + 1)*(entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE):
+ // check (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE)
+ if ((entrySize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
+ // check (numEntries + 1)
+ (numEntries > UINT32_MAX-1) ||
+ // check (numEntries + 1)*(entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE)
+ (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX/(numEntries+1))) {
+ return false;
+ }
+
return (initWithCapacity((numEntries + 1) * (DATA_QUEUE_ENTRY_HEADER_SIZE + entrySize)));
}
void IODataQueue::free()
{
- if (dataQueue) {
- IOFreeAligned(dataQueue, round_page(dataQueue->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE));
+ if (notifyMsg) {
+ if (dataQueue) {
+ IOFreeAligned(dataQueue, round_page(((IODataQueueInternal *)notifyMsg)->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE));
+ dataQueue = NULL;
+ }
+
+ IODelete(notifyMsg, IODataQueueInternal, 1);
+ notifyMsg = NULL;
}
super::free();
@@ -101,34 +156,68 @@
Boolean IODataQueue::enqueue(void * data, UInt32 dataSize)
{
- const UInt32 head = dataQueue->head; // volatile
- const UInt32 tail = dataQueue->tail;
+ UInt32 head;
+ UInt32 tail;
+ UInt32 newTail;
const UInt32 entrySize = dataSize + DATA_QUEUE_ENTRY_HEADER_SIZE;
+ UInt32 queueSize;
IODataQueueEntry * entry;
-
+
+ // Check for overflow of entrySize
+ if (dataSize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) {
+ return false;
+ }
+
+ // 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 underflow of (dataQueue->queueSize - tail)
+ queueSize = ((IODataQueueInternal *) notifyMsg)->queueSize;
+ if ((queueSize < tail) || (queueSize < head)) {
+ return false;
+ }
+
if ( tail >= head )
{
- if ( (tail + entrySize) < dataQueue->queueSize )
+ // Is there enough room at the end for the entry?
+ if ((entrySize <= UINT32_MAX - tail) &&
+ ((tail + entrySize) <= queueSize) )
{
entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
entry->size = dataSize;
memcpy(&entry->data, data, dataSize);
- dataQueue->tail += entrySize;
- }
- else if ( head > entrySize )
+
+ // 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;
- ((IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail))->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 ( ( queueSize - tail ) >= DATA_QUEUE_ENTRY_HEADER_SIZE )
+ {
+ ((IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail))->size = dataSize;
+ }
+
memcpy(&dataQueue->queue->data, data, dataSize);
- dataQueue->tail = entrySize;
+ newTail = entrySize;
}
else
{
- return false; // queue is full
+ return false; // queue is full
}
}
else
@@ -142,56 +231,61 @@
entry->size = dataSize;
memcpy(&entry->data, data, dataSize);
- dataQueue->tail += entrySize;
+ newTail = tail + entrySize;
}
else
{
- return false; // queue is full
- }
- }
-
- // Send notification (via mach message) that data is available.
-
- if ( ( head == tail ) /* queue was empty prior to enqueue() */
- || ( dataQueue->head == tail ) ) /* queue was emptied during enqueue() */
- {
- sendDataAvailableNotification();
- }
-
- return true;
+ 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;
}
void IODataQueue::setNotificationPort(mach_port_t port)
{
- static struct _notifyMsg init_msg = { {
- MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0),
- sizeof (struct _notifyMsg),
- MACH_PORT_NULL,
- MACH_PORT_NULL,
- 0,
- 0
- } };
-
- if (notifyMsg == 0) {
- notifyMsg = IOMalloc(sizeof(struct _notifyMsg));
- }
-
- *((struct _notifyMsg *)notifyMsg) = init_msg;
-
- ((struct _notifyMsg *)notifyMsg)->h.msgh_remote_port = port;
+ mach_msg_header_t * msgh;
+
+ msgh = &((IODataQueueInternal *) notifyMsg)->msg;
+ bzero(msgh, sizeof(mach_msg_header_t));
+ msgh->msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0);
+ msgh->msgh_size = sizeof(mach_msg_header_t);
+ msgh->msgh_remote_port = port;
}
void IODataQueue::sendDataAvailableNotification()
{
- kern_return_t kr;
- mach_msg_header_t * msgh;
-
- msgh = (mach_msg_header_t *)notifyMsg;
- if (msgh) {
- kr = mach_msg_send_from_kernel(msgh, msgh->msgh_size);
+ kern_return_t kr;
+ mach_msg_header_t * msgh;
+
+ msgh = &((IODataQueueInternal *) notifyMsg)->msg;
+ if (msgh->msgh_remote_port) {
+ kr = mach_msg_send_from_kernel_with_options(msgh, msgh->msgh_size, MACH_SEND_TIMEOUT, MACH_MSG_TIMEOUT_NONE);
switch(kr) {
- case MACH_SEND_TIMED_OUT: // Notification already sent
+ case MACH_SEND_TIMED_OUT: // Notification already sent
case MACH_MSG_SUCCESS:
+ case MACH_SEND_NO_BUFFER:
break;
default:
IOLog("%s: dataAvailableNotification failed - msg_send returned: %d\n", /*getName()*/"IODataQueue", kr);
@@ -203,11 +297,14 @@
IOMemoryDescriptor *IODataQueue::getMemoryDescriptor()
{
IOMemoryDescriptor *descriptor = 0;
-
+ UInt32 queueSize;
+
+ queueSize = ((IODataQueueInternal *) notifyMsg)->queueSize;
if (dataQueue != 0) {
- descriptor = IOMemoryDescriptor::withAddress(dataQueue, dataQueue->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE, kIODirectionOutIn);
+ descriptor = IOMemoryDescriptor::withAddress(dataQueue, queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE, kIODirectionOutIn);
}
return descriptor;
}
+