Milestone 5: deliver embedded RDP sessions and lifecycle hardening

third_party/FreeRDP/winpr/libwinpr/thread/apc.c

@@ -0,0 +1,272 @@
+/**
+ * FreeRDP: A Remote Desktop Protocol Implementation
+ * APC implementation
+ *
+ * Copyright 2021 David Fort <contact@hardening-consulting.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.
+ */
+#ifndef _WIN32
+
+#include "apc.h"
+#include "thread.h"
+#include "../log.h"
+#include "../synch/pollset.h"
+#include <winpr/assert.h>
+
+#define TAG WINPR_TAG("apc")
+
+BOOL apc_init(APC_QUEUE* apc)
+{
+	pthread_mutexattr_t attr;
+	BOOL ret = FALSE;
+
+	WINPR_ASSERT(apc);
+
+	pthread_mutexattr_init(&attr);
+	if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE) != 0)
+	{
+		WLog_ERR(TAG, "failed to initialize mutex attributes to recursive");
+		return FALSE;
+	}
+
+	memset(apc, 0, sizeof(*apc));
+
+	if (pthread_mutex_init(&apc->mutex, &attr) != 0)
+	{
+		WLog_ERR(TAG, "failed to initialize main thread APC mutex");
+		goto out;
+	}
+
+	ret = TRUE;
+out:
+	pthread_mutexattr_destroy(&attr);
+	return ret;
+}
+
+BOOL apc_uninit(APC_QUEUE* apc)
+{
+	WINPR_ASSERT(apc);
+	return pthread_mutex_destroy(&apc->mutex) == 0;
+}
+
+void apc_register(WINPR_THREAD* thread, WINPR_APC_ITEM* addItem)
+{
+	WINPR_APC_ITEM** nextp = nullptr;
+	APC_QUEUE* apc = nullptr;
+
+	WINPR_ASSERT(thread);
+	WINPR_ASSERT(addItem);
+
+	apc = &thread->apc;
+	WINPR_ASSERT(apc);
+
+	pthread_mutex_lock(&apc->mutex);
+	if (apc->tail)
+	{
+		nextp = &apc->tail->next;
+		addItem->last = apc->tail;
+	}
+	else
+	{
+		nextp = &apc->head;
+	}
+
+	*nextp = addItem;
+	apc->tail = addItem;
+	apc->length++;
+
+	addItem->markedForRemove = FALSE;
+	addItem->boundThread = GetCurrentThreadId();
+	addItem->linked = TRUE;
+	pthread_mutex_unlock(&apc->mutex);
+}
+
+static inline void apc_item_remove(APC_QUEUE* apc, WINPR_APC_ITEM* item)
+{
+	WINPR_ASSERT(apc);
+	WINPR_ASSERT(item);
+
+	if (!item->last)
+		apc->head = item->next;
+	else
+		item->last->next = item->next;
+
+	if (!item->next)
+		apc->tail = item->last;
+	else
+		item->next->last = item->last;
+
+	apc->length--;
+}
+
+APC_REMOVE_RESULT apc_remove(WINPR_APC_ITEM* item)
+{
+	WINPR_THREAD* thread = winpr_GetCurrentThread();
+	APC_QUEUE* apc = nullptr;
+	APC_REMOVE_RESULT ret = APC_REMOVE_OK;
+
+	WINPR_ASSERT(item);
+
+	if (!item->linked)
+		return APC_REMOVE_OK;
+
+	if (item->boundThread != GetCurrentThreadId())
+	{
+		WLog_ERR(TAG, "removing an APC entry should be done in the creating thread");
+		return APC_REMOVE_ERROR;
+	}
+
+	if (!thread)
+	{
+		WLog_ERR(TAG, "unable to retrieve current thread");
+		return APC_REMOVE_ERROR;
+	}
+
+	apc = &thread->apc;
+	WINPR_ASSERT(apc);
+
+	pthread_mutex_lock(&apc->mutex);
+	if (apc->treatingCompletions)
+	{
+		item->markedForRemove = TRUE;
+		ret = APC_REMOVE_DELAY_FREE;
+		goto out;
+	}
+
+	apc_item_remove(apc, item);
+
+out:
+	pthread_mutex_unlock(&apc->mutex);
+	item->boundThread = 0xFFFFFFFF;
+	item->linked = FALSE;
+	return ret;
+}
+
+BOOL apc_collectFds(WINPR_THREAD* thread, WINPR_POLL_SET* set, BOOL* haveAutoSignaled)
+{
+	WINPR_APC_ITEM* item = nullptr;
+	BOOL ret = FALSE;
+	APC_QUEUE* apc = nullptr;
+
+	WINPR_ASSERT(thread);
+	WINPR_ASSERT(haveAutoSignaled);
+
+	apc = &thread->apc;
+	WINPR_ASSERT(apc);
+
+	*haveAutoSignaled = FALSE;
+	pthread_mutex_lock(&apc->mutex);
+	item = apc->head;
+	for (; item; item = item->next)
+	{
+		if (item->alwaysSignaled)
+		{
+			*haveAutoSignaled = TRUE;
+		}
+		else if (!pollset_add(set, item->pollFd, item->pollMode))
+			goto out;
+	}
+
+	ret = TRUE;
+out:
+	pthread_mutex_unlock(&apc->mutex);
+	return ret;
+}
+
+int apc_executeCompletions(WINPR_THREAD* thread, WINPR_POLL_SET* set, size_t startIndex)
+{
+	APC_QUEUE* apc = nullptr;
+	WINPR_APC_ITEM* nextItem = nullptr;
+	size_t idx = startIndex;
+	int ret = 0;
+
+	WINPR_ASSERT(thread);
+
+	apc = &thread->apc;
+	WINPR_ASSERT(apc);
+
+	pthread_mutex_lock(&apc->mutex);
+	apc->treatingCompletions = TRUE;
+
+	/* first pass to compute signaled items */
+	for (WINPR_APC_ITEM* item = apc->head; item; item = item->next)
+	{
+		item->isSignaled = item->alwaysSignaled || pollset_isSignaled(set, idx);
+		if (!item->alwaysSignaled)
+			idx++;
+	}
+
+	/* second pass: run completions */
+	for (WINPR_APC_ITEM* item = apc->head; item; item = nextItem)
+	{
+		if (item->isSignaled)
+		{
+			if (item->completion && !item->markedForRemove)
+				item->completion(item->completionArgs);
+			ret++;
+		}
+
+		nextItem = item->next;
+	}
+
+	/* third pass: to do final cleanup */
+	for (WINPR_APC_ITEM* item = apc->head; item; item = nextItem)
+	{
+		nextItem = item->next;
+
+		if (item->markedForRemove)
+		{
+			apc_item_remove(apc, item);
+			if (item->markedForFree)
+				free(item);
+		}
+	}
+
+	apc->treatingCompletions = FALSE;
+	pthread_mutex_unlock(&apc->mutex);
+
+	return ret;
+}
+
+void apc_cleanupThread(WINPR_THREAD* thread)
+{
+	WINPR_APC_ITEM* item = nullptr;
+	WINPR_APC_ITEM* nextItem = nullptr;
+	APC_QUEUE* apc = nullptr;
+
+	WINPR_ASSERT(thread);
+
+	apc = &thread->apc;
+	WINPR_ASSERT(apc);
+
+	pthread_mutex_lock(&apc->mutex);
+	item = apc->head;
+	for (; item; item = nextItem)
+	{
+		nextItem = item->next;
+
+		if (item->type == APC_TYPE_HANDLE_FREE)
+			item->completion(item->completionArgs);
+
+		item->last = item->next = nullptr;
+		item->linked = FALSE;
+		if (item->markedForFree)
+			free(item);
+	}
+
+	apc->head = apc->tail = nullptr;
+	pthread_mutex_unlock(&apc->mutex);
+}
+
+#endif