Milestone 5: deliver embedded RDP sessions and lifecycle hardening

third_party/FreeRDP/winpr/libwinpr/utils/collections/MessageQueue.c

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+/**
+ * WinPR: Windows Portable Runtime
+ * Message Queue
+ *
+ * Copyright 2012 Marc-Andre Moreau <marcandre.moreau@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <winpr/config.h>
+
+#include <winpr/crt.h>
+#include <winpr/sysinfo.h>
+#include <winpr/assert.h>
+
+#include <winpr/collections.h>
+
+struct s_wMessageQueue
+{
+	size_t head;
+	size_t tail;
+	size_t size;
+	size_t capacity;
+	BOOL closed;
+	wMessage* array;
+	CRITICAL_SECTION lock;
+	HANDLE event;
+
+	wObject object;
+};
+
+/**
+ * Message Queue inspired from Windows:
+ * http://msdn.microsoft.com/en-us/library/ms632590/
+ */
+
+/**
+ * Properties
+ */
+
+wObject* MessageQueue_Object(wMessageQueue* queue)
+{
+	WINPR_ASSERT(queue);
+	return &queue->object;
+}
+
+/**
+ * Gets an event which is set when the queue is non-empty
+ */
+
+HANDLE MessageQueue_Event(wMessageQueue* queue)
+{
+	WINPR_ASSERT(queue);
+	return queue->event;
+}
+
+/**
+ * Gets the queue size
+ */
+
+size_t MessageQueue_Size(wMessageQueue* queue)
+{
+	WINPR_ASSERT(queue);
+	EnterCriticalSection(&queue->lock);
+	const size_t ret = queue->size;
+	LeaveCriticalSection(&queue->lock);
+	return ret;
+}
+
+size_t MessageQueue_Capacity(wMessageQueue* queue)
+{
+	WINPR_ASSERT(queue);
+	EnterCriticalSection(&queue->lock);
+	const size_t ret = queue->capacity;
+	LeaveCriticalSection(&queue->lock);
+	return ret;
+}
+
+/**
+ * Methods
+ */
+
+BOOL MessageQueue_Wait(wMessageQueue* queue)
+{
+	BOOL status = FALSE;
+
+	WINPR_ASSERT(queue);
+	if (WaitForSingleObject(queue->event, INFINITE) == WAIT_OBJECT_0)
+		status = TRUE;
+
+	return status;
+}
+
+static BOOL MessageQueue_EnsureCapacity(wMessageQueue* queue, size_t count)
+{
+	const size_t increment = 128;
+	WINPR_ASSERT(queue);
+
+	const size_t required = queue->size + count;
+	// check for overflow
+	if ((required < queue->size) || (required < count) ||
+	    (required > (SIZE_MAX - increment) / sizeof(wMessage)))
+		return FALSE;
+
+	if (required > queue->capacity)
+	{
+		const size_t old_capacity = queue->capacity;
+		const size_t new_capacity = required + increment;
+
+		wMessage* new_arr = (wMessage*)realloc(queue->array, sizeof(wMessage) * new_capacity);
+		if (!new_arr)
+			return FALSE;
+		queue->array = new_arr;
+		queue->capacity = new_capacity;
+		ZeroMemory(&(queue->array[old_capacity]), (new_capacity - old_capacity) * sizeof(wMessage));
+
+		/* rearrange wrapped entries:
+		 * fill up the newly available space and move tail
+		 * back by the amount of elements that have been moved to the newly
+		 * allocated space.
+		 */
+		if (queue->tail <= queue->head)
+		{
+			size_t tocopy = queue->tail;
+			size_t slots = new_capacity - old_capacity;
+			const size_t batch = (tocopy < slots) ? tocopy : slots;
+			CopyMemory(&(queue->array[old_capacity]), queue->array, batch * sizeof(wMessage));
+
+			/* Tail is decremented. if the whole thing is appended
+			 * just move the existing tail by old_capacity */
+			if (tocopy < slots)
+			{
+				ZeroMemory(queue->array, batch * sizeof(wMessage));
+				queue->tail += old_capacity;
+			}
+			else
+			{
+				const size_t remain = queue->tail - batch;
+				const size_t movesize = remain * sizeof(wMessage);
+				memmove_s(queue->array, queue->tail * sizeof(wMessage), &queue->array[batch],
+				          movesize);
+
+				const size_t zerooffset = remain;
+				const size_t zerosize = (queue->tail - remain) * sizeof(wMessage);
+				ZeroMemory(&queue->array[zerooffset], zerosize);
+				queue->tail -= batch;
+			}
+		}
+	}
+
+	return TRUE;
+}
+
+BOOL MessageQueue_Dispatch(wMessageQueue* queue, const wMessage* message)
+{
+	wMessage* dst = nullptr;
+	BOOL ret = FALSE;
+	WINPR_ASSERT(queue);
+
+	if (!message)
+		return FALSE;
+
+	WINPR_ASSERT(queue);
+	EnterCriticalSection(&queue->lock);
+
+	if (queue->closed)
+		goto out;
+
+	if (!MessageQueue_EnsureCapacity(queue, 1))
+		goto out;
+
+	dst = &(queue->array[queue->tail]);
+	*dst = *message;
+	dst->time = GetTickCount64();
+
+	queue->tail = (queue->tail + 1) % queue->capacity;
+	queue->size++;
+
+	if (queue->size > 0)
+		(void)SetEvent(queue->event);
+
+	if (message->id == WMQ_QUIT)
+		queue->closed = TRUE;
+
+	ret = TRUE;
+out:
+	LeaveCriticalSection(&queue->lock);
+	return ret;
+}
+
+BOOL MessageQueue_Post(wMessageQueue* queue, void* context, UINT32 type, void* wParam, void* lParam)
+{
+	wMessage message = WINPR_C_ARRAY_INIT;
+
+	message.context = context;
+	message.id = type;
+	message.wParam = wParam;
+	message.lParam = lParam;
+	message.Free = nullptr;
+
+	return MessageQueue_Dispatch(queue, &message);
+}
+
+BOOL MessageQueue_PostQuit(wMessageQueue* queue, int nExitCode)
+{
+	return MessageQueue_Post(queue, nullptr, WMQ_QUIT, (void*)(size_t)nExitCode, nullptr);
+}
+
+int MessageQueue_Get(wMessageQueue* queue, wMessage* message)
+{
+	int status = -1;
+
+	if (!MessageQueue_Wait(queue))
+		return status;
+
+	EnterCriticalSection(&queue->lock);
+
+	if (queue->size > 0)
+	{
+		CopyMemory(message, &(queue->array[queue->head]), sizeof(wMessage));
+		ZeroMemory(&(queue->array[queue->head]), sizeof(wMessage));
+		queue->head = (queue->head + 1) % queue->capacity;
+		queue->size--;
+
+		if (queue->size < 1)
+			(void)ResetEvent(queue->event);
+
+		status = (message->id != WMQ_QUIT) ? 1 : 0;
+	}
+
+	LeaveCriticalSection(&queue->lock);
+
+	return status;
+}
+
+int MessageQueue_Peek(wMessageQueue* queue, wMessage* message, BOOL remove)
+{
+	int status = 0;
+
+	WINPR_ASSERT(queue);
+	EnterCriticalSection(&queue->lock);
+
+	if (queue->size > 0)
+	{
+		CopyMemory(message, &(queue->array[queue->head]), sizeof(wMessage));
+		status = 1;
+
+		if (remove)
+		{
+			ZeroMemory(&(queue->array[queue->head]), sizeof(wMessage));
+			queue->head = (queue->head + 1) % queue->capacity;
+			queue->size--;
+
+			if (queue->size < 1)
+				(void)ResetEvent(queue->event);
+		}
+	}
+
+	LeaveCriticalSection(&queue->lock);
+
+	return status;
+}
+
+/**
+ * Construction, Destruction
+ */
+
+wMessageQueue* MessageQueue_New(const wObject* callback)
+{
+	wMessageQueue* queue = nullptr;
+
+	queue = (wMessageQueue*)calloc(1, sizeof(wMessageQueue));
+	if (!queue)
+		return nullptr;
+
+	if (!InitializeCriticalSectionAndSpinCount(&queue->lock, 4000))
+		goto fail;
+
+	if (!MessageQueue_EnsureCapacity(queue, 32))
+		goto fail;
+
+	queue->event = CreateEvent(nullptr, TRUE, FALSE, nullptr);
+	if (!queue->event)
+		goto fail;
+
+	if (callback)
+		queue->object = *callback;
+
+	return queue;
+
+fail:
+	WINPR_PRAGMA_DIAG_PUSH
+	WINPR_PRAGMA_DIAG_IGNORED_MISMATCHED_DEALLOC
+	MessageQueue_Free(queue);
+	WINPR_PRAGMA_DIAG_POP
+	return nullptr;
+}
+
+void MessageQueue_Free(wMessageQueue* queue)
+{
+	if (!queue)
+		return;
+
+	if (queue->event)
+		MessageQueue_Clear(queue);
+
+	(void)CloseHandle(queue->event);
+	DeleteCriticalSection(&queue->lock);
+
+	free(queue->array);
+	free(queue);
+}
+
+int MessageQueue_Clear(wMessageQueue* queue)
+{
+	int status = 0;
+
+	WINPR_ASSERT(queue);
+	WINPR_ASSERT(queue->event);
+
+	EnterCriticalSection(&queue->lock);
+
+	while (queue->size > 0)
+	{
+		wMessage* msg = &(queue->array[queue->head]);
+
+		/* Free resources of message. */
+		if (queue->object.fnObjectUninit)
+			queue->object.fnObjectUninit(msg);
+		if (queue->object.fnObjectFree)
+			queue->object.fnObjectFree(msg);
+
+		ZeroMemory(msg, sizeof(wMessage));
+
+		queue->head = (queue->head + 1) % queue->capacity;
+		queue->size--;
+	}
+	(void)ResetEvent(queue->event);
+	queue->closed = FALSE;
+
+	LeaveCriticalSection(&queue->lock);
+
+	return status;
+}