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// Copyright (c) 2009 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_BROWSER_MACH_BROKER_H_
#define CHROME_BROWSER_MACH_BROKER_H_
#pragma once
#include <map>
#include <string>
#include <mach/mach.h>
#include "base/process.h"
#include "base/process_util.h"
#include "base/singleton.h"
#include "base/synchronization/lock.h"
#include "chrome/common/notification_observer.h"
#include "chrome/common/notification_registrar.h"
// On OS X, the mach_port_t of a process is required to collect metrics about
// the process. Running |task_for_pid()| is only allowed for privileged code.
// However, a process has port rights to all its subprocesses, so let the
// browser's child processes send their Mach port to the browser over IPC.
// This way, the brower can at least collect metrics of its child processes,
// which is what it's most interested in anyway.
//
// Mach ports can only be sent over Mach IPC, not over the |socketpair()| that
// the regular IPC system uses. Hence, the child processes open a Mach
// connection shortly after launching and ipc their mach data to the browser
// process. This data is kept in a global |MachBroker| object.
//
// Since this data arrives over a separate channel, it is not available
// immediately after a child process has been started.
class MachBroker : public base::ProcessMetrics::PortProvider,
public NotificationObserver {
public:
// Returns the global MachBroker.
static MachBroker* GetInstance();
// Performs any necessary setup that cannot happen in the constructor.
// Clients MUST call this method before fork()ing any children.
void PrepareForFork();
struct MachInfo {
MachInfo() : mach_task_(MACH_PORT_NULL) {}
MachInfo& SetTask(mach_port_t task) {
mach_task_ = task;
return *this;
}
mach_port_t mach_task_;
};
// Adds a placeholder to the map for the given pid with MACH_PORT_NULL.
// Callers are expected to later update the port with FinalizePid(). Callers
// MUST acquire the lock given by GetLock() before calling this method (and
// release the lock afterwards).
void AddPlaceholderForPid(base::ProcessHandle pid);
// Updates the mapping for |pid| to include the given |mach_info|. Does
// nothing if PlaceholderForPid() has not already been called for the given
// |pid|. Callers MUST acquire the lock given by GetLock() before calling
// this method (and release the lock afterwards).
void FinalizePid(base::ProcessHandle pid, const MachInfo& mach_info);
// Removes all mappings belonging to |pid| from the broker.
void InvalidatePid(base::ProcessHandle pid);
// The lock that protects this MachBroker object. Clients MUST acquire and
// release this lock around calls to PlaceholderForPid() and FinalizePid().
base::Lock& GetLock();
// Returns the Mach port name to use when sending or receiving messages.
// Does the Right Thing in the browser and in child processes.
static std::string GetMachPortName();
// Implement |ProcessMetrics::PortProvider|.
virtual mach_port_t TaskForPid(base::ProcessHandle process) const;
// Implement |NotificationObserver|.
virtual void Observe(NotificationType type,
const NotificationSource& source,
const NotificationDetails& details);
private:
// Private constructor.
MachBroker();
// True if the listener thread has been started.
bool listener_thread_started_;
// Used to register for notifications received by NotificationObserver.
// Accessed only on the UI thread.
NotificationRegistrar registrar_;
// Stores mach info for every process in the broker.
typedef std::map<base::ProcessHandle, MachInfo> MachMap;
MachMap mach_map_;
// Mutex that guards |mach_map_|.
mutable base::Lock lock_;
friend class MachBrokerTest;
friend class RegisterNotificationTask;
// Needed in order to make the constructor private.
friend struct DefaultSingletonTraits<MachBroker>;
DISALLOW_COPY_AND_ASSIGN(MachBroker);
};
#endif // CHROME_BROWSER_MACH_BROKER_H_
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