The Tor Browser: mozglue/build/Nuwa.h@b8a032363ba2 (annotated)

mozglue/build/Nuwa.h@b8a032363ba2 (annotated)

mozglue/build/Nuwa.h

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set sw=2 ts=2 autoindent cindent expandtab: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef __NUWA_H_
 #define __NUWA_H_
 #include <setjmp.h>
 #include <unistd.h>
 #include "mozilla/Types.h"
 /**
  * Nuwa is a goddess who created mankind according to her figure in the
  * ancient Chinese mythology.
  */
 // Max number of top level protocol that can be handled by Nuwa process.
 #ifndef NUWA_TOPLEVEL_MAX
 #define NUWA_TOPLEVEL_MAX 8
 #endif
 struct NuwaProtoFdInfo {
     int protoId;
     int originFd;
     int newFds[2];
 };
 #define NUWA_NEWFD_PARENT 0
 #define NUWA_NEWFD_CHILD 1
 extern "C" {
 /**
  * The following 3 methods are used to synchronously spawn the Nuwa process.
  * The typical usage is:
  *
  *   The IPC thread                                The main thread
  *   1. Receives the request.
  *   2. NuwaSpawnPrepare().
  *   3. Request main thread to
  *      spawn. --------------------------------------+
  *   4. NuwaSpawnWait().                             V
  *                                                 5. NuwaSpawn() to clone all
  *                                                    the threads in the Nuwa
  *                                                    process (including main
  *                                                    & IPC threads).
  *                                                 6. NuwaSpawn() finishes and
  *            +-------------------------------------- signals NuwaSpawnWait().
  *            V
  *   7. NuwaSpawnWait() returns.
  */
 /**
  * Prepare for spawning a new process. The calling thread (typically the IPC
  * thread) will block further requests to spawn a new process.
  */
 MFBT_API void NuwaSpawnPrepare();
 /**
  * Called on the thread that receives the request. Used to wait until
  * NuwaSpawn() finishes and maintain the stack of the calling thread.
  */
 MFBT_API void NuwaSpawnWait();
 /**
  * Spawn a new content process, called in the Nuwa process. This has to run on
  * the main thread.
  *
  * @return The process ID of the new process.
  */
 MFBT_API pid_t NuwaSpawn();
 /**
  * The following methods are for marking threads created in the Nuwa process so
  * they can be frozen and then recreated in the spawned process. All threads
  * except the main thread must be marked by one of the following 4 methods;
  * otherwise, we have a thread that is created but unknown to us. The Nuwa
  * process will never become ready and this needs to be fixed.
  */
 /**
  * Mark the current thread as supporting Nuwa. The thread will implicitly freeze
  * by calling a blocking method such as pthread_mutex_lock() or epoll_wait().
  *
  * @param recreate The custom function that will be called in the spawned
  *                 process, after the thread is recreated. Can be nullptr if no
  *                 custom function to be called after the thread is recreated.
  * @param arg The argument passed to the custom function. Can be nullptr.
  */
 MFBT_API void NuwaMarkCurrentThread(void (*recreate)(void *), void *arg);
 /**
  * Mark the current thread as not supporting Nuwa. The calling thread will not
  * be automatically cloned from the Nuwa process to spawned process. If this
  * thread needs to be created in the spawned process, use NuwaAddConstructor()
  * or NuwaAddFinalConstructor() to do it.
  */
 MFBT_API void NuwaSkipCurrentThread();
 /**
  * Force the current thread to freeze explicitly at the current point.
  */
 MFBT_API void NuwaFreezeCurrentThread();
 /**
  * Helper functions for the NuwaCheckpointCurrentThread() macro.
  */
 MFBT_API jmp_buf* NuwaCheckpointCurrentThread1();
 MFBT_API bool NuwaCheckpointCurrentThread2(int setjmpCond);
 /**
  * Set the point to recover after thread recreation. The calling thread is not
  * blocked. This is used for the thread that cannot freeze (i.e. the IPC
  * thread).
  */
 #define NuwaCheckpointCurrentThread() \
   NuwaCheckpointCurrentThread2(setjmp(*NuwaCheckpointCurrentThread1()))
 /**
  * The following methods are called in the initialization stage of the Nuwa
  * process.
  */
 /**
  * Prepare for making the Nuwa process.
  */
 MFBT_API void PrepareNuwaProcess();
 /**
  * Make the current process a Nuwa process. Start to freeze the threads.
  */
 MFBT_API void MakeNuwaProcess();
 /**
  * Register a method to be invoked after a new process is spawned. The method
  * will be invoked on the main thread.
  *
  * @param construct The method to be invoked.
  * @param arg The argument passed to the method.
  */
 MFBT_API void NuwaAddConstructor(void (*construct)(void *), void *arg);
 /**
  * Register a method to be invoked after a new process is spawned and threads
  * are recreated. The method will be invoked on the main thread.
  *
  * @param construct The method to be invoked.
  * @param arg The argument passed to the method.
  */
 MFBT_API void NuwaAddFinalConstructor(void (*construct)(void *), void *arg);
 /**
  * The methods to query the Nuwa-related states.
  */
 /**
  * @return If the current process is the Nuwa process.
  */
 MFBT_API bool IsNuwaProcess();
 /**
  * @return If the Nuwa process is ready for spawning new processes.
  */
 MFBT_API bool IsNuwaReady();
 };
 #endif /* __NUWA_H_ */

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