1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/mozglue/build/Nuwa.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,171 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* vim: set sw=2 ts=2 autoindent cindent expandtab: */
1.6 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this file,
1.8 + * You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#ifndef __NUWA_H_
1.11 +#define __NUWA_H_
1.12 +
1.13 +#include <setjmp.h>
1.14 +#include <unistd.h>
1.15 +
1.16 +#include "mozilla/Types.h"
1.17 +
1.18 +/**
1.19 + * Nuwa is a goddess who created mankind according to her figure in the
1.20 + * ancient Chinese mythology.
1.21 + */
1.22 +
1.23 +// Max number of top level protocol that can be handled by Nuwa process.
1.24 +#ifndef NUWA_TOPLEVEL_MAX
1.25 +#define NUWA_TOPLEVEL_MAX 8
1.26 +#endif
1.27 +
1.28 +struct NuwaProtoFdInfo {
1.29 + int protoId;
1.30 + int originFd;
1.31 + int newFds[2];
1.32 +};
1.33 +
1.34 +#define NUWA_NEWFD_PARENT 0
1.35 +#define NUWA_NEWFD_CHILD 1
1.36 +
1.37 +extern "C" {
1.38 +
1.39 +/**
1.40 + * The following 3 methods are used to synchronously spawn the Nuwa process.
1.41 + * The typical usage is:
1.42 + *
1.43 + * The IPC thread The main thread
1.44 + * 1. Receives the request.
1.45 + * 2. NuwaSpawnPrepare().
1.46 + * 3. Request main thread to
1.47 + * spawn. --------------------------------------+
1.48 + * 4. NuwaSpawnWait(). V
1.49 + * 5. NuwaSpawn() to clone all
1.50 + * the threads in the Nuwa
1.51 + * process (including main
1.52 + * & IPC threads).
1.53 + * 6. NuwaSpawn() finishes and
1.54 + * +-------------------------------------- signals NuwaSpawnWait().
1.55 + * V
1.56 + * 7. NuwaSpawnWait() returns.
1.57 + */
1.58 +
1.59 +/**
1.60 + * Prepare for spawning a new process. The calling thread (typically the IPC
1.61 + * thread) will block further requests to spawn a new process.
1.62 + */
1.63 +MFBT_API void NuwaSpawnPrepare();
1.64 +
1.65 +/**
1.66 + * Called on the thread that receives the request. Used to wait until
1.67 + * NuwaSpawn() finishes and maintain the stack of the calling thread.
1.68 + */
1.69 +MFBT_API void NuwaSpawnWait();
1.70 +
1.71 +/**
1.72 + * Spawn a new content process, called in the Nuwa process. This has to run on
1.73 + * the main thread.
1.74 + *
1.75 + * @return The process ID of the new process.
1.76 + */
1.77 +MFBT_API pid_t NuwaSpawn();
1.78 +
1.79 +/**
1.80 + * The following methods are for marking threads created in the Nuwa process so
1.81 + * they can be frozen and then recreated in the spawned process. All threads
1.82 + * except the main thread must be marked by one of the following 4 methods;
1.83 + * otherwise, we have a thread that is created but unknown to us. The Nuwa
1.84 + * process will never become ready and this needs to be fixed.
1.85 + */
1.86 +
1.87 +/**
1.88 + * Mark the current thread as supporting Nuwa. The thread will implicitly freeze
1.89 + * by calling a blocking method such as pthread_mutex_lock() or epoll_wait().
1.90 + *
1.91 + * @param recreate The custom function that will be called in the spawned
1.92 + * process, after the thread is recreated. Can be nullptr if no
1.93 + * custom function to be called after the thread is recreated.
1.94 + * @param arg The argument passed to the custom function. Can be nullptr.
1.95 + */
1.96 +MFBT_API void NuwaMarkCurrentThread(void (*recreate)(void *), void *arg);
1.97 +
1.98 +/**
1.99 + * Mark the current thread as not supporting Nuwa. The calling thread will not
1.100 + * be automatically cloned from the Nuwa process to spawned process. If this
1.101 + * thread needs to be created in the spawned process, use NuwaAddConstructor()
1.102 + * or NuwaAddFinalConstructor() to do it.
1.103 + */
1.104 +MFBT_API void NuwaSkipCurrentThread();
1.105 +
1.106 +/**
1.107 + * Force the current thread to freeze explicitly at the current point.
1.108 + */
1.109 +MFBT_API void NuwaFreezeCurrentThread();
1.110 +
1.111 +/**
1.112 + * Helper functions for the NuwaCheckpointCurrentThread() macro.
1.113 + */
1.114 +MFBT_API jmp_buf* NuwaCheckpointCurrentThread1();
1.115 +
1.116 +MFBT_API bool NuwaCheckpointCurrentThread2(int setjmpCond);
1.117 +
1.118 +/**
1.119 + * Set the point to recover after thread recreation. The calling thread is not
1.120 + * blocked. This is used for the thread that cannot freeze (i.e. the IPC
1.121 + * thread).
1.122 + */
1.123 +#define NuwaCheckpointCurrentThread() \
1.124 + NuwaCheckpointCurrentThread2(setjmp(*NuwaCheckpointCurrentThread1()))
1.125 +
1.126 +/**
1.127 + * The following methods are called in the initialization stage of the Nuwa
1.128 + * process.
1.129 + */
1.130 +
1.131 +/**
1.132 + * Prepare for making the Nuwa process.
1.133 + */
1.134 +MFBT_API void PrepareNuwaProcess();
1.135 +
1.136 +/**
1.137 + * Make the current process a Nuwa process. Start to freeze the threads.
1.138 + */
1.139 +MFBT_API void MakeNuwaProcess();
1.140 +
1.141 +/**
1.142 + * Register a method to be invoked after a new process is spawned. The method
1.143 + * will be invoked on the main thread.
1.144 + *
1.145 + * @param construct The method to be invoked.
1.146 + * @param arg The argument passed to the method.
1.147 + */
1.148 +MFBT_API void NuwaAddConstructor(void (*construct)(void *), void *arg);
1.149 +
1.150 +/**
1.151 + * Register a method to be invoked after a new process is spawned and threads
1.152 + * are recreated. The method will be invoked on the main thread.
1.153 + *
1.154 + * @param construct The method to be invoked.
1.155 + * @param arg The argument passed to the method.
1.156 + */
1.157 +MFBT_API void NuwaAddFinalConstructor(void (*construct)(void *), void *arg);
1.158 +
1.159 +/**
1.160 + * The methods to query the Nuwa-related states.
1.161 + */
1.162 +
1.163 +/**
1.164 + * @return If the current process is the Nuwa process.
1.165 + */
1.166 +MFBT_API bool IsNuwaProcess();
1.167 +
1.168 +/**
1.169 + * @return If the Nuwa process is ready for spawning new processes.
1.170 + */
1.171 +MFBT_API bool IsNuwaReady();
1.172 +};
1.173 +
1.174 +#endif /* __NUWA_H_ */
