1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/chrome/common/process_watcher_posix_sigchld.cc Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,215 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + * vim: set ts=8 et sw=2 tw=80:
1.6 + */
1.7 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.8 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.9 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.10 +
1.11 +#include <errno.h>
1.12 +#include <signal.h>
1.13 +#include <sys/types.h>
1.14 +#include <sys/wait.h>
1.15 +
1.16 +#include "base/eintr_wrapper.h"
1.17 +#include "base/message_loop.h"
1.18 +#include "base/process_util.h"
1.19 +
1.20 +#include "chrome/common/process_watcher.h"
1.21 +
1.22 +// Maximum amount of time (in milliseconds) to wait for the process to exit.
1.23 +// XXX/cjones: fairly arbitrary, chosen to match process_watcher_win.cc
1.24 +static const int kMaxWaitMs = 2000;
1.25 +
1.26 +namespace {
1.27 +
1.28 +bool
1.29 +IsProcessDead(pid_t process)
1.30 +{
1.31 + bool exited = false;
1.32 + // don't care if the process crashed, just if it exited
1.33 + base::DidProcessCrash(&exited, process);
1.34 + return exited;
1.35 +}
1.36 +
1.37 +
1.38 +class ChildReaper : public base::MessagePumpLibevent::SignalEvent,
1.39 + public base::MessagePumpLibevent::SignalWatcher
1.40 +{
1.41 +public:
1.42 + explicit ChildReaper(pid_t process) : process_(process)
1.43 + {
1.44 + }
1.45 +
1.46 + virtual ~ChildReaper()
1.47 + {
1.48 + // subclasses should have cleaned up |process_| already
1.49 + DCHECK(!process_);
1.50 +
1.51 + // StopCatching() is implicit
1.52 + }
1.53 +
1.54 + // @override
1.55 + virtual void OnSignal(int sig)
1.56 + {
1.57 + DCHECK(SIGCHLD == sig);
1.58 + DCHECK(process_);
1.59 +
1.60 + // this may be the SIGCHLD for a process other than |process_|
1.61 + if (IsProcessDead(process_)) {
1.62 + process_ = 0;
1.63 + StopCatching();
1.64 + }
1.65 + }
1.66 +
1.67 +protected:
1.68 + void WaitForChildExit()
1.69 + {
1.70 + DCHECK(process_);
1.71 + HANDLE_EINTR(waitpid(process_, NULL, 0));
1.72 + }
1.73 +
1.74 + pid_t process_;
1.75 +
1.76 +private:
1.77 + DISALLOW_EVIL_CONSTRUCTORS(ChildReaper);
1.78 +};
1.79 +
1.80 +
1.81 +// Fear the reaper
1.82 +class ChildGrimReaper : public ChildReaper,
1.83 + public Task
1.84 +{
1.85 +public:
1.86 + explicit ChildGrimReaper(pid_t process) : ChildReaper(process)
1.87 + {
1.88 + }
1.89 +
1.90 + virtual ~ChildGrimReaper()
1.91 + {
1.92 + if (process_)
1.93 + KillProcess();
1.94 + }
1.95 +
1.96 + // @override
1.97 + virtual void Run()
1.98 + {
1.99 + // we may have already been signaled by the time this runs
1.100 + if (process_)
1.101 + KillProcess();
1.102 + }
1.103 +
1.104 +private:
1.105 + void KillProcess()
1.106 + {
1.107 + DCHECK(process_);
1.108 +
1.109 + if (IsProcessDead(process_)) {
1.110 + process_ = 0;
1.111 + return;
1.112 + }
1.113 +
1.114 + if (0 == kill(process_, SIGKILL)) {
1.115 + // XXX this will block for whatever amount of time it takes the
1.116 + // XXX OS to tear down the process's resources. might need to
1.117 + // XXX rethink this if it proves expensive
1.118 + WaitForChildExit();
1.119 + }
1.120 + else {
1.121 + CHROMIUM_LOG(ERROR) << "Failed to deliver SIGKILL to " << process_ << "!"
1.122 + << "("<< errno << ").";
1.123 + }
1.124 + process_ = 0;
1.125 + }
1.126 +
1.127 + DISALLOW_EVIL_CONSTRUCTORS(ChildGrimReaper);
1.128 +};
1.129 +
1.130 +
1.131 +class ChildLaxReaper : public ChildReaper,
1.132 + public MessageLoop::DestructionObserver
1.133 +{
1.134 +public:
1.135 + explicit ChildLaxReaper(pid_t process) : ChildReaper(process)
1.136 + {
1.137 + }
1.138 +
1.139 + virtual ~ChildLaxReaper()
1.140 + {
1.141 + // WillDestroyCurrentMessageLoop() should have reaped process_ already
1.142 + DCHECK(!process_);
1.143 + }
1.144 +
1.145 + // @override
1.146 + virtual void OnSignal(int sig)
1.147 + {
1.148 + ChildReaper::OnSignal(sig);
1.149 +
1.150 + if (!process_) {
1.151 + MessageLoop::current()->RemoveDestructionObserver(this);
1.152 + delete this;
1.153 + }
1.154 + }
1.155 +
1.156 + // @override
1.157 + virtual void WillDestroyCurrentMessageLoop()
1.158 + {
1.159 + DCHECK(process_);
1.160 +
1.161 + WaitForChildExit();
1.162 + process_ = 0;
1.163 +
1.164 + // XXX don't think this is necessary, since destruction can only
1.165 + // be observed once, but can't hurt
1.166 + MessageLoop::current()->RemoveDestructionObserver(this);
1.167 + delete this;
1.168 + }
1.169 +
1.170 +private:
1.171 + DISALLOW_EVIL_CONSTRUCTORS(ChildLaxReaper);
1.172 +};
1.173 +
1.174 +} // namespace <anon>
1.175 +
1.176 +
1.177 +/**
1.178 + * Do everything possible to ensure that |process| has been reaped
1.179 + * before this process exits.
1.180 + *
1.181 + * |grim| decides how strict to be with the child's shutdown.
1.182 + *
1.183 + * | child exit timeout | upon parent shutdown:
1.184 + * +--------------------+----------------------------------
1.185 + * force=true | 2 seconds | kill(child, SIGKILL)
1.186 + * force=false | infinite | waitpid(child)
1.187 + *
1.188 + * If a child process doesn't shut down properly, and |grim=false|
1.189 + * used, then the parent will wait on the child forever. So,
1.190 + * |force=false| is expected to be used when an external entity can be
1.191 + * responsible for terminating hung processes, e.g. automated test
1.192 + * harnesses.
1.193 + */
1.194 +void
1.195 +ProcessWatcher::EnsureProcessTerminated(base::ProcessHandle process,
1.196 + bool force)
1.197 +{
1.198 + DCHECK(process != base::GetCurrentProcId());
1.199 + DCHECK(process > 0);
1.200 +
1.201 + if (IsProcessDead(process))
1.202 + return;
1.203 +
1.204 + MessageLoopForIO* loop = MessageLoopForIO::current();
1.205 + if (force) {
1.206 + ChildGrimReaper* reaper = new ChildGrimReaper(process);
1.207 +
1.208 + loop->CatchSignal(SIGCHLD, reaper, reaper);
1.209 + // |loop| takes ownership of |reaper|
1.210 + loop->PostDelayedTask(FROM_HERE, reaper, kMaxWaitMs);
1.211 + } else {
1.212 + ChildLaxReaper* reaper = new ChildLaxReaper(process);
1.213 +
1.214 + loop->CatchSignal(SIGCHLD, reaper, reaper);
1.215 + // |reaper| destroys itself after destruction notification
1.216 + loop->AddDestructionObserver(reaper);
1.217 + }
1.218 +}
