ipc/glue/ForkServiceChild.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6 #ifndef __FORKSERVICE_CHILD_H_
   7 #define __FORKSERVICE_CHILD_H_
   8
   9 #include "base/process_util.h"
  10 #include "mozilla/GeckoArgs.h"
  11 #include "nsIObserver.h"
  12 #include "nsString.h"
  13 #include "mozilla/ipc/MiniTransceiver.h"
  14 #include "mozilla/ipc/LaunchError.h"
  15 #include "mozilla/Result.h"
  16
  17 #include <sys/types.h>
  18 #include <poll.h>
  19
  20 namespace mozilla {
  21 namespace ipc {
  22
  23 class GeckoChildProcessHost;
  24
  25 /**
  26  * This is the interface to the fork server.
  27  *
  28  * When the chrome process calls |ForkServiceChild| to create a new
  29  * process, this class send a message to the fork server through a
  30  * pipe and get the PID of the new process from the reply.
  31  */
  32 class ForkServiceChild {
  33  public:
  34   ForkServiceChild(int aFd, GeckoChildProcessHost* aProcess);
  35   virtual ~ForkServiceChild();
  36
  37   /**
  38    * Ask the fork server to create a new process with given parameters.
  39    *
  40    * \param aArgs arguments with file attachments used in the content process.
  41    * \param aOptions other options which will be used to create the process.
  42    *                 Not all launch options are supported.
  43    * \param aPid returns the PID of the content
  44    * process created. \return true if success.
  45    */
  46   Result<Ok, LaunchError> SendForkNewSubprocess(
  47       geckoargs::ChildProcessArgs&& aArgs, base::LaunchOptions&& aOptions,
  48       pid_t* aPid);
  49
  50   /**
  51    * Create a fork server process and the singleton of this class.
  52    *
  53    * This function uses |GeckoChildProcessHost| to launch the fork
  54    * server, getting the fd of a pipe/socket to the fork server from
  55    * it's |IPC::Channel|.
  56    */
  57   static void StartForkServer();
  58   static void StopForkServer();
  59
  60   /**
  61    * Return the singleton.
  62    */
  63   static ForkServiceChild* Get() {
  64     auto child = sForkServiceChild.get();
  65     return child == nullptr || child->mFailed ? nullptr : child;
  66   }
  67
  68   /**
  69    * Returns whether the fork server was ever active.  Thread-safe.
  70    */
  71   static bool WasUsed() { return sForkServiceUsed; }
  72
  73  private:
  74   // Called when a message is received.
  75   void OnMessageReceived(UniquePtr<IPC::Message> message);
  76   void OnError();
  77
  78   UniquePtr<MiniTransceiver> mTcver;
  79   static UniquePtr<ForkServiceChild> sForkServiceChild;
  80   static Atomic<bool> sForkServiceUsed;
  81   pid_t mRecvPid;
  82   bool mFailed;  // The forkserver has crashed or disconnected.
  83   GeckoChildProcessHost* mProcess;
  84 };
  85
  86 /**
  87  * Start a fork server at |xpcom-startup| from the chrome process.
  88  */
  89 class ForkServerLauncher : public nsIObserver {
  90  public:
  91   NS_DECL_ISUPPORTS
  92   NS_DECL_NSIOBSERVER
  93
  94   ForkServerLauncher();
  95   static already_AddRefed<ForkServerLauncher> Create();
  96
  97  private:
  98   friend class ForkServiceChild;
  99   virtual ~ForkServerLauncher();
 100
 101   static void RestartForkServer();
 102
 103   static bool mHaveStartedClient;
 104   static StaticRefPtr<ForkServerLauncher> mSingleton;
 105 };
 106
 107 }  // namespace ipc
 108 }  // namespace mozilla
 109
 110 #endif /* __FORKSERVICE_CHILD_H_ */