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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
// Copyright (c) 2006-2008 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.
#ifndef CHROME_COMMON_IPC_CHANNEL_H_
#define CHROME_COMMON_IPC_CHANNEL_H_
#include <cstdint>
#include <queue>
#include "base/basictypes.h"
#include "base/process.h"
#include "build/build_config.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/UniquePtrExtensions.h"
#include "mozilla/WeakPtr.h"
#include "chrome/common/ipc_message.h"
#ifdef OS_WIN
# include <string>
#endif
namespace IPC {
class Message;
class MessageReader;
class MessageWriter;
//------------------------------------------------------------------------------
class Channel {
// Security tests need access to the pipe handle.
friend class ChannelTest;
public:
// Windows channels use named objects and connect to them by name,
// but on Unix we use unnamed socketpairs and pass capabilities
// directly using SCM_RIGHTS messages. This type abstracts away
// that difference.
#ifdef OS_WIN
typedef std::wstring ChannelId;
#else
struct ChannelId {};
#endif
// For channels which are created after initialization, handles to the pipe
// endpoints may be passed around directly using IPC messages.
using ChannelHandle = mozilla::UniqueFileHandle;
// Implemented by consumers of a Channel to receive messages.
//
// All listeners will only be called on the IO thread, and must be destroyed
// on the IO thread.
class Listener : public mozilla::SupportsWeakPtr {
public:
virtual ~Listener() = default;
// Called when a message is received.
virtual void OnMessageReceived(mozilla::UniquePtr<Message> message) = 0;
// Called when the channel is connected and we have received the internal
// Hello message from the peer.
virtual void OnChannelConnected(base::ProcessId peer_pid) {}
// Called when an error is detected that causes the channel to close.
// This method is not called when a channel is closed normally.
virtual void OnChannelError() {}
// If the listener has queued messages, swap them for |queue| like so
// swap(impl->my_queued_messages, queue);
virtual void GetQueuedMessages(
std::queue<mozilla::UniquePtr<Message>>& queue) {}
};
enum Mode { MODE_SERVER, MODE_CLIENT };
enum {
// The maximum message size in bytes. Attempting to receive a
// message of this size or bigger results in a channel error.
// This is larger in fuzzing builds to allow the fuzzing of passing
// large data structures into DOM methods without crashing.
#ifndef FUZZING
kMaximumMessageSize = 256 * 1024 * 1024,
#else
kMaximumMessageSize = 1792 * 1024 * 1024, // 1.75GB
#endif
// Amount of data to read at once from the pipe.
kReadBufferSize = 4 * 1024,
};
// Initialize a Channel.
//
// |channel_id| identifies the communication Channel.
// |mode| specifies whether this Channel is to operate in server mode or
// client mode. In server mode, the Channel is responsible for setting up the
// IPC object, whereas in client mode, the Channel merely connects to the
// already established IPC object.
// |listener| receives a callback on the current thread for each newly
// received message.
//
// The Channel must be created and destroyed on the IO thread, and all
// methods, unless otherwise noted, are only safe to call on the I/O thread.
//
Channel(const ChannelId& channel_id, Mode mode, Listener* listener);
// Initialize a pre-created channel |pipe| as |mode|.
Channel(ChannelHandle pipe, Mode mode, Listener* listener);
~Channel();
// Connect the pipe. On the server side, this will initiate
// waiting for connections. On the client, it attempts to
// connect to a pre-existing pipe. Note, calling Connect()
// will not block the calling thread and may complete
// asynchronously.
bool Connect();
// Close this Channel explicitly. May be called multiple times.
void Close();
// Modify the Channel's listener.
Listener* set_listener(Listener* listener);
// Send a message over the Channel to the listener on the other end.
//
// This method may be called from any thread, so long as the `Channel` is not
// destroyed before it returns.
//
// If you Send() a message on a Close()'d channel, we delete the message
// immediately.
bool Send(mozilla::UniquePtr<Message> message);
// The PID which this channel has been opened with. This will be
// `-1` until `OnChannelConnected` has been called.
int32_t OtherPid() const;
// IsClosed() is safe to call from any thread, but the value returned may
// be out of date.
bool IsClosed() const;
#if defined(OS_POSIX)
// On POSIX an IPC::Channel wraps a socketpair(), this method returns the
// FD # for the client end of the socket and the equivalent FD# to use for
// mapping it into the Child process.
// This method may only be called on the server side of a channel.
void GetClientFileDescriptorMapping(int* src_fd, int* dest_fd) const;
// Close the client side of the socketpair.
void CloseClientFileDescriptor();
# if defined(OS_MACOSX)
// Configure the mach task_t for the peer task.
void SetOtherMachTask(task_t task);
// Tell this pipe to accept mach ports. Exactly one side of the IPC connection
// must be set as `MODE_SERVER` and that side will be responsible for
// transferring the rights between processes.
void StartAcceptingMachPorts(Mode mode);
# endif
#elif defined(OS_WIN)
// Tell this pipe to accept handles. Exactly one side of the IPC connection
// must be set as `MODE_SERVER`, and that side will be responsible for calling
// `DuplicateHandle` to transfer the handle between processes.
void StartAcceptingHandles(Mode mode);
#endif // defined(OS_POSIX)
// On Windows: Generates a channel ID that, if passed to the client
// as a shared secret, will validate the client's authenticity.
// Other platforms don't use channel IDs, so this returns the dummy
// ChannelId value.
static ChannelId GenerateVerifiedChannelID();
// On Windows: Retrieves the initial channel ID passed to the
// current process by its parent. Other platforms don't do this;
// the dummy ChannelId value is returned instead.
static ChannelId ChannelIDForCurrentProcess();
#if defined(MOZ_WIDGET_ANDROID)
// Used to set the first IPC file descriptor in the child process on Android.
// See ipc_channel_posix.cc for further details on how this is used.
static void SetClientChannelFd(int fd);
#endif // defined(MOZ_WIDGET_ANDROID)
// Create a new pair of pipe endpoints which can be used to establish a
// native IPC::Channel connection.
static bool CreateRawPipe(ChannelHandle* server, ChannelHandle* client);
private:
// PIMPL to which all channel calls are delegated.
class ChannelImpl;
RefPtr<ChannelImpl> channel_impl_;
enum {
#if defined(OS_MACOSX)
// If the channel receives a message that contains file descriptors, then
// it will reply back with this message, indicating that the message has
// been received. The sending channel can then close any descriptors that
// had been marked as auto_close. This works around a sendmsg() bug on BSD
// where the kernel can eagerly close file descriptors that are in message
// queues but not yet delivered.
RECEIVED_FDS_MESSAGE_TYPE = kuint16max - 1,
#endif
// The Hello message is internal to the Channel class. It is sent
// by the peer when the channel is connected. The message contains
// just the process id (pid). The message has a special routing_id
// (MSG_ROUTING_NONE) and type (HELLO_MESSAGE_TYPE).
HELLO_MESSAGE_TYPE = kuint16max // Maximum value of message type
// (uint16_t), to avoid conflicting with
// normal message types, which are
// enumeration constants starting from 0.
};
};
} // namespace IPC
#endif // CHROME_COMMON_IPC_CHANNEL_H_
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