blob: 785af4dc6127cdfa8c99fa91b92f574d714a0651 [file] [log] [blame]
// Copyright 2014 The Crashpad Authors. All rights reserved.
// 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
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
#include <mach/mach.h>
#include <map>
#include <set>
#include "base/macros.h"
#include "util/mach/mach_message_server.h"
namespace crashpad {
//! \brief Adapts multiple MachMessageServer::Interface implementations for
//! simultaneous use in a single MachMessageServer::Run() call.
//! This class implements a MachMessageServer::Interface that contains other
//! MachMessageServer::Interface objects.
//! In some situations, it may be desirable for a Mach message server to handle
//! messages from distinct MIG subsystems with distinct
//! MachMessageServer::Interface implementations. This may happen if a single
//! receive right is shared for multiple subsystems, or if distinct receive
//! rights are combined in a Mach port set. In these cases, this class performs
//! a first-level demultiplexing to forward request messages to the proper
//! subsystem-level demultiplexers.
class CompositeMachMessageServer : public MachMessageServer::Interface {
//! \brief Adds a handler that messages can be dispatched to based on request
//! message ID.
//! \param[in] handler A MachMessageServer handler. Ownership of this object
//! is not taken. Cycles must not be created between objects. It is
//! invalid to add an object as its own handler.
//! If \a handler claims to support any request ID that this object is already
//! able to handle, execution will be terminated.
void AddHandler(MachMessageServer::Interface* handler);
// MachMessageServer::Interface:
//! \copydoc MachMessageServer::Interface::MachMessageServerFunction()
//! This implementation forwards the message to an appropriate handler added
//! by AddHandler() on the basis of the \a in request message’s message ID. If
//! no appropriate handler exists, the \a out reply message is treated as a
//! `mig_reply_error_t`, its return code is set to `MIG_BAD_ID`, and `false`
//! is returned.
bool MachMessageServerFunction(const mach_msg_header_t* in,
mach_msg_header_t* out,
bool* destroy_complex_request) override;
//! \copydoc MachMessageServer::Interface::MachMessageServerRequestIDs()
//! This implementation returns the set of all request message Mach message
//! IDs of all handlers added by AddHandler().
std::set<mach_msg_id_t> MachMessageServerRequestIDs() override;
//! \copydoc MachMessageServer::Interface::MachMessageServerRequestSize()
//! This implementation returns the maximum request message size of all
//! handlers added by AddHandler(). If no handlers are present, returns the
//! size of `mach_msg_header_t`, the minimum size of a MIG request message
//! that can be received for demultiplexing purposes.
mach_msg_size_t MachMessageServerRequestSize() override;
//! \copydoc MachMessageServer::Interface::MachMessageServerReplySize()
//! This implementation returns the maximum reply message size of all handlers
//! added by AddHandler(). If no handlers are present, returns the size of
//! `mig_reply_error_t`, the minimum size of a MIG reply message.
mach_msg_size_t MachMessageServerReplySize() override;
using HandlerMap = std::map<mach_msg_id_t, MachMessageServer::Interface*>;
HandlerMap handler_map_; // weak
mach_msg_size_t request_size_;
mach_msg_size_t reply_size_;
} // namespace crashpad