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// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <set>
#include <vector>
#include "base/macros.h"
#include "base/process/port_provider_mac.h"
#include "base/synchronization/lock.h"
#include "mojo/core/channel.h"
namespace mojo {
namespace core {
// The MachPortRelay is used by a privileged process, usually the root process,
// to manipulate Mach ports in a child process. Ports can be added to and
// extracted from a child process that has registered itself with the
// |base::PortProvider| used by this class.
class MachPortRelay : public base::PortProvider::Observer {
class Observer {
// Called by the MachPortRelay to notify observers that a new process is
// ready for Mach ports to be sent/received. There are no guarantees about
// the thread this is called on, including the presence of a MessageLoop.
// Implementations must not call AddObserver() or RemoveObserver() during
// this function, as doing so will deadlock.
virtual void OnProcessReady(base::ProcessHandle process) = 0;
// Used by a child process to receive Mach ports from a sender (privileged)
// process. The Mach port in |port| is interpreted as an intermediate Mach
// port. It replaces each Mach port with the final Mach port received from the
// intermediate port. This method takes ownership of the intermediate Mach
// port and gives ownership of the final Mach port to the caller.
// On failure, returns a null send right.
// See SendPortsToProcess() for the definition of intermediate and final Mach
// ports.
static base::mac::ScopedMachSendRight ReceiveSendRight(
base::mac::ScopedMachReceiveRight port);
explicit MachPortRelay(base::PortProvider* port_provider);
~MachPortRelay() override;
// Sends the Mach ports attached to |message| to |process|.
// For each Mach port attached to |message|, a new Mach port, the intermediate
// port, is created in |process|. The message's Mach port is then sent over
// this intermediate port and the message is modified to refer to the name of
// the intermediate port. The Mach port received over the intermediate port in
// the child is referred to as the final Mach port.
// All ports in |message|'s set of handles are reset by this call, and all
// port names in the message's header are replaced with the new receive right
// ports.
void SendPortsToProcess(Channel::Message* message,
base::ProcessHandle process);
// Given the name of a Mach send right within |process|, extracts an owned
// send right ref and returns it. May return a null port on failure.
base::mac::ScopedMachSendRight ExtractPort(mach_port_t port_name,
base::ProcessHandle process);
// Observer interface.
void AddObserver(Observer* observer);
void RemoveObserver(Observer* observer);
base::PortProvider* port_provider() const { return port_provider_; }
// base::PortProvider::Observer implementation.
void OnReceivedTaskPort(base::ProcessHandle process) override;
base::PortProvider* const port_provider_;
base::Lock observers_lock_;
std::set<Observer*> observers_;
} // namespace core
} // namespace mojo