1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
#include <errno.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "base/eintr_wrapper.h"
#include "base/message_loop.h"
#include "base/process_util.h"
#include "chrome/common/process_watcher.h"
// Maximum amount of time (in milliseconds) to wait for the process to exit.
// XXX/cjones: fairly arbitrary, chosen to match process_watcher_win.cc
static const int kMaxWaitMs = 2000;
namespace {
bool
IsProcessDead(pid_t process)
{
bool exited = false;
// don't care if the process crashed, just if it exited
base::DidProcessCrash(&exited, process);
return exited;
}
class ChildReaper : public base::MessagePumpLibevent::SignalEvent,
public base::MessagePumpLibevent::SignalWatcher
{
public:
explicit ChildReaper(pid_t process) : process_(process)
{
}
virtual ~ChildReaper()
{
// subclasses should have cleaned up |process_| already
DCHECK(!process_);
// StopCatching() is implicit
}
// @override
virtual void OnSignal(int sig)
{
DCHECK(SIGCHLD == sig);
DCHECK(process_);
// this may be the SIGCHLD for a process other than |process_|
if (IsProcessDead(process_)) {
process_ = 0;
StopCatching();
}
}
protected:
void WaitForChildExit()
{
DCHECK(process_);
HANDLE_EINTR(waitpid(process_, NULL, 0));
}
pid_t process_;
private:
DISALLOW_EVIL_CONSTRUCTORS(ChildReaper);
};
// Fear the reaper
class ChildGrimReaper : public ChildReaper,
public mozilla::Runnable
{
public:
explicit ChildGrimReaper(pid_t process) : ChildReaper(process)
{
}
virtual ~ChildGrimReaper()
{
if (process_)
KillProcess();
}
NS_IMETHOD Run() override
{
// we may have already been signaled by the time this runs
if (process_)
KillProcess();
return NS_OK;
}
private:
void KillProcess()
{
DCHECK(process_);
if (IsProcessDead(process_)) {
process_ = 0;
return;
}
if (0 == kill(process_, SIGKILL)) {
// XXX this will block for whatever amount of time it takes the
// XXX OS to tear down the process's resources. might need to
// XXX rethink this if it proves expensive
WaitForChildExit();
}
else {
CHROMIUM_LOG(ERROR) << "Failed to deliver SIGKILL to " << process_ << "!"
<< "("<< errno << ").";
}
process_ = 0;
}
DISALLOW_EVIL_CONSTRUCTORS(ChildGrimReaper);
};
class ChildLaxReaper : public ChildReaper,
public MessageLoop::DestructionObserver
{
public:
explicit ChildLaxReaper(pid_t process) : ChildReaper(process)
{
}
virtual ~ChildLaxReaper()
{
// WillDestroyCurrentMessageLoop() should have reaped process_ already
DCHECK(!process_);
}
// @override
virtual void OnSignal(int sig)
{
ChildReaper::OnSignal(sig);
if (!process_) {
MessageLoop::current()->RemoveDestructionObserver(this);
delete this;
}
}
// @override
virtual void WillDestroyCurrentMessageLoop()
{
DCHECK(process_);
WaitForChildExit();
process_ = 0;
// XXX don't think this is necessary, since destruction can only
// be observed once, but can't hurt
MessageLoop::current()->RemoveDestructionObserver(this);
delete this;
}
private:
DISALLOW_EVIL_CONSTRUCTORS(ChildLaxReaper);
};
} // namespace <anon>
/**
* Do everything possible to ensure that |process| has been reaped
* before this process exits.
*
* |grim| decides how strict to be with the child's shutdown.
*
* | child exit timeout | upon parent shutdown:
* +--------------------+----------------------------------
* force=true | 2 seconds | kill(child, SIGKILL)
* force=false | infinite | waitpid(child)
*
* If a child process doesn't shut down properly, and |grim=false|
* used, then the parent will wait on the child forever. So,
* |force=false| is expected to be used when an external entity can be
* responsible for terminating hung processes, e.g. automated test
* harnesses.
*/
void
ProcessWatcher::EnsureProcessTerminated(base::ProcessHandle process,
bool force)
{
DCHECK(process != base::GetCurrentProcId());
DCHECK(process > 0);
if (IsProcessDead(process))
return;
MessageLoopForIO* loop = MessageLoopForIO::current();
if (force) {
RefPtr<ChildGrimReaper> reaper = new ChildGrimReaper(process);
loop->CatchSignal(SIGCHLD, reaper, reaper);
// |loop| takes ownership of |reaper|
loop->PostDelayedTask(reaper.forget(), kMaxWaitMs);
} else {
ChildLaxReaper* reaper = new ChildLaxReaper(process);
loop->CatchSignal(SIGCHLD, reaper, reaper);
// |reaper| destroys itself after destruction notification
loop->AddDestructionObserver(reaper);
}
}
|
