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/*
* Copyright (C) 2010-2020 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "Attachment.h"
#include "MessageNames.h"
#include "ReceiverMatcher.h"
#include <wtf/ArgumentCoder.h>
#include <wtf/Function.h>
#include <wtf/OptionSet.h>
#include <wtf/Vector.h>
#if PLATFORM(MAC)
#include "ImportanceAssertion.h"
#endif
namespace IPC {
enum class MessageFlags : uint8_t;
enum class ShouldDispatchWhenWaitingForSyncReply : uint8_t;
template<typename, typename> struct ArgumentCoder;
template<typename, typename, typename> struct HasLegacyDecoder;
template<typename, typename, typename> struct HasModernDecoder;
class Decoder {
WTF_MAKE_FAST_ALLOCATED;
public:
static std::unique_ptr<Decoder> create(const uint8_t* buffer, size_t bufferSize, Vector<Attachment>&&);
using BufferDeallocator = Function<void(const uint8_t*, size_t)>;
static std::unique_ptr<Decoder> create(const uint8_t* buffer, size_t bufferSize, BufferDeallocator&&, Vector<Attachment>&&);
Decoder(const uint8_t* stream, size_t streamSize, uint64_t destinationID);
~Decoder();
Decoder(const Decoder&) = delete;
Decoder(Decoder&&) = delete;
Decoder& operator=(const Decoder&) = delete;
Decoder& operator=(Decoder&&) = delete;
ReceiverName messageReceiverName() const { return receiverName(m_messageName); }
MessageName messageName() const { return m_messageName; }
uint64_t destinationID() const { return m_destinationID; }
bool matches(const ReceiverMatcher& matcher) const { return matcher.matches(messageReceiverName(), destinationID()); }
bool isSyncMessage() const { return messageIsSync(messageName()); }
ShouldDispatchWhenWaitingForSyncReply shouldDispatchMessageWhenWaitingForSyncReply() const;
bool isAllowedWhenWaitingForSyncReply() const { return messageAllowedWhenWaitingForSyncReply(messageName()) || m_isAllowedWhenWaitingForSyncReplyOverride; }
bool isAllowedWhenWaitingForUnboundedSyncReply() const { return messageAllowedWhenWaitingForUnboundedSyncReply(messageName()); }
bool shouldUseFullySynchronousModeForTesting() const;
bool shouldMaintainOrderingWithAsyncMessages() const;
void setIsAllowedWhenWaitingForSyncReplyOverride(bool value) { m_isAllowedWhenWaitingForSyncReplyOverride = value; }
#if PLATFORM(MAC)
void setImportanceAssertion(ImportanceAssertion&&);
#endif
static std::unique_ptr<Decoder> unwrapForTesting(Decoder&);
const uint8_t* buffer() const { return m_buffer; }
size_t currentBufferPosition() const { return m_bufferPos - m_buffer; }
size_t length() const { return m_bufferEnd - m_buffer; }
WARN_UNUSED_RETURN bool isValid() const { return m_bufferPos != nullptr; }
void markInvalid() { m_bufferPos = nullptr; }
template<typename T>
WARN_UNUSED_RETURN std::span<const T> decodeSpan(size_t);
template<typename T>
WARN_UNUSED_RETURN std::optional<T> decodeObject();
template<typename T>
WARN_UNUSED_RETURN bool decode(T& t)
{
using Impl = ArgumentCoder<std::remove_cvref_t<T>, void>;
if constexpr(HasLegacyDecoder<T, Impl>::value) {
if (UNLIKELY(!Impl::decode(*this, t))) {
markInvalid();
return false;
}
} else {
std::optional<T> optional { decode<T>() };
if (UNLIKELY(!optional)) {
markInvalid();
return false;
}
t = WTFMove(*optional);
}
return true;
}
template<typename T>
Decoder& operator>>(std::optional<T>& t)
{
t = decode<T>();
return *this;
}
// The preferred decode() function. Can decode T which is not default constructible when T
// has a modern decoder, e.g decoding function that returns std::optional.
template<typename T>
std::optional<T> decode()
{
using Impl = ArgumentCoder<std::remove_cvref_t<T>, void>;
if constexpr(HasModernDecoder<T, Impl>::value) {
std::optional<T> t { Impl::decode(*this) };
if (UNLIKELY(!t))
markInvalid();
return t;
} else {
std::optional<T> t { T { } };
if (LIKELY(Impl::decode(*this, *t)))
return t;
markInvalid();
return std::nullopt;
}
}
std::optional<Attachment> takeLastAttachment();
static constexpr bool isIPCDecoder = true;
private:
Decoder(const uint8_t* buffer, size_t bufferSize, BufferDeallocator&&, Vector<Attachment>&&);
const uint8_t* m_buffer;
const uint8_t* m_bufferPos;
const uint8_t* m_bufferEnd;
BufferDeallocator m_bufferDeallocator;
Vector<Attachment> m_attachments;
OptionSet<MessageFlags> m_messageFlags;
MessageName m_messageName;
uint64_t m_destinationID;
bool m_isAllowedWhenWaitingForSyncReplyOverride { false };
#if PLATFORM(MAC)
ImportanceAssertion m_importanceAssertion;
#endif
};
inline bool alignedBufferIsLargeEnoughToContain(const uint8_t* alignedPosition, const uint8_t* bufferStart, const uint8_t* bufferEnd, size_t size)
{
// When size == 0 for the last argument and it's a variable length byte array,
// bufferStart == alignedPosition == bufferEnd, so checking (bufferEnd >= alignedPosition)
// is not an off-by-one error since (static_cast<size_t>(bufferEnd - alignedPosition) >= size)
// will catch issues when size != 0.
return bufferEnd >= alignedPosition && bufferStart <= alignedPosition && static_cast<size_t>(bufferEnd - alignedPosition) >= size;
}
template<typename T>
inline std::span<const T> Decoder::decodeSpan(size_t size)
{
if (size > std::numeric_limits<size_t>::max() / sizeof(T))
return { };
const uint8_t* alignedPosition = roundUpToMultipleOf<alignof(T)>(m_bufferPos);
if (UNLIKELY(!alignedBufferIsLargeEnoughToContain(alignedPosition, m_buffer, m_bufferEnd, size * sizeof(T)))) {
markInvalid();
return { };
}
m_bufferPos = alignedPosition + size * sizeof(T);
return { reinterpret_cast<const T*>(alignedPosition), size };
}
template<typename T>
inline std::optional<T> Decoder::decodeObject()
{
static_assert(std::is_trivially_copyable_v<T>);
auto data = decodeSpan<T>(1);
if (!data.data())
return std::nullopt;
return data[0];
}
} // namespace IPC
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