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1 // Copyright 2017 The Chromium Authors. All rights reserved. | 1 // Copyright 2017 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "content/browser/tracing/arc_tracing_agent.h" | 5 #include "content/browser/tracing/arc_tracing_agent.h" |
6 | 6 |
| 7 #include <memory> |
7 #include <string> | 8 #include <string> |
| 9 #include <utility> |
| 10 #include <vector> |
8 | 11 |
9 #include "base/bind.h" | 12 #include "base/bind.h" |
| 13 #include "base/bind_helpers.h" |
| 14 #include "base/files/file.h" |
| 15 #include "base/files/file_descriptor_watcher_posix.h" |
10 #include "base/logging.h" | 16 #include "base/logging.h" |
| 17 #include "base/memory/ptr_util.h" |
11 #include "base/memory/singleton.h" | 18 #include "base/memory/singleton.h" |
12 #include "base/threading/thread_checker.h" | 19 #include "base/memory/weak_ptr.h" |
| 20 #include "base/posix/unix_domain_socket_linux.h" |
| 21 #include "base/threading/sequenced_task_runner_handle.h" |
13 #include "base/threading/thread_task_runner_handle.h" | 22 #include "base/threading/thread_task_runner_handle.h" |
| 23 #include "base/time/time.h" |
| 24 #include "cc/base/ring_buffer.h" |
| 25 #include "content/public/browser/browser_thread.h" |
14 | 26 |
15 namespace content { | 27 namespace content { |
16 | 28 |
17 namespace { | 29 namespace { |
18 | 30 |
| 31 // The maximum size used to store one trace event. The ad hoc trace format for |
| 32 // atrace is 1024 bytes. Here we add additional size as we're using JSON and |
| 33 // have additional data fields. |
| 34 constexpr size_t kArcTraceMessageLength = 1024 + 512; |
| 35 |
19 constexpr char kArcTracingAgentName[] = "arc"; | 36 constexpr char kArcTracingAgentName[] = "arc"; |
20 constexpr char kArcTraceLabel[] = "ArcTraceEvents"; | 37 constexpr char kArcTraceLabel[] = "ArcTraceEvents"; |
21 | 38 |
22 void OnStopTracing(bool success) { | 39 // Number of events for the ring buffer. |
23 DLOG_IF(WARNING, !success) << "Failed to stop ARC tracing."; | 40 constexpr size_t kTraceEventBufferSize = 64000; |
24 } | 41 |
| 42 // A helper class for reading trace data from the client side. We separate this |
| 43 // from |ArcTracingAgentImpl| to isolate the logic that runs on browser's IO |
| 44 // thread. All the functions in this class except for constructor, destructor, |
| 45 // and |GetWeakPtr| are expected to be run on browser's IO thread. |
| 46 class ArcTracingReader { |
| 47 public: |
| 48 using StopTracingCallback = |
| 49 base::Callback<void(const scoped_refptr<base::RefCountedString>&)>; |
| 50 |
| 51 ArcTracingReader() : weak_ptr_factory_(this) {} |
| 52 |
| 53 void StartTracing(base::ScopedFD read_fd) { |
| 54 DCHECK_CURRENTLY_ON(BrowserThread::IO); |
| 55 read_fd_ = std::move(read_fd); |
| 56 // We don't use the weak pointer returned by |GetWeakPtr| to avoid using it |
| 57 // on different task runner. Instead, we use |base::Unretained| here as |
| 58 // |fd_watcher_| is always destroyed before |this| is destroyed. |
| 59 fd_watcher_ = base::FileDescriptorWatcher::WatchReadable( |
| 60 read_fd_.get(), base::Bind(&ArcTracingReader::OnTraceDataAvailable, |
| 61 base::Unretained(this))); |
| 62 } |
| 63 |
| 64 void OnTraceDataAvailable() { |
| 65 DCHECK_CURRENTLY_ON(BrowserThread::IO); |
| 66 |
| 67 char buf[kArcTraceMessageLength]; |
| 68 std::vector<base::ScopedFD> unused_fds; |
| 69 ssize_t n = base::UnixDomainSocket::RecvMsg( |
| 70 read_fd_.get(), buf, kArcTraceMessageLength, &unused_fds); |
| 71 // When EOF, return and do nothing. The clean up is done in StopTracing. |
| 72 if (n == 0) |
| 73 return; |
| 74 |
| 75 if (n < 0) { |
| 76 DPLOG(WARNING) << "Unexpected error while reading trace from client."; |
| 77 // Do nothing here as StopTracing will do the clean up and the existing |
| 78 // trace logs will be returned. |
| 79 return; |
| 80 } |
| 81 |
| 82 if (n > static_cast<ssize_t>(kArcTraceMessageLength)) { |
| 83 DLOG(WARNING) << "Unexpected data size when reading trace from client."; |
| 84 return; |
| 85 } |
| 86 ring_buffer_.SaveToBuffer(std::string(buf, n)); |
| 87 } |
| 88 |
| 89 void StopTracing(const StopTracingCallback& callback) { |
| 90 DCHECK_CURRENTLY_ON(BrowserThread::IO); |
| 91 fd_watcher_.reset(); |
| 92 read_fd_.reset(); |
| 93 |
| 94 bool append_comma = false; |
| 95 std::string data; |
| 96 for (auto it = ring_buffer_.Begin(); it; ++it) { |
| 97 if (append_comma) |
| 98 data.append(","); |
| 99 else |
| 100 append_comma = true; |
| 101 data.append(**it); |
| 102 } |
| 103 ring_buffer_.Clear(); |
| 104 |
| 105 BrowserThread::PostTask( |
| 106 BrowserThread::IO, FROM_HERE, |
| 107 base::Bind(callback, base::RefCountedString::TakeString(&data))); |
| 108 } |
| 109 |
| 110 base::WeakPtr<ArcTracingReader> GetWeakPtr() { |
| 111 return weak_ptr_factory_.GetWeakPtr(); |
| 112 } |
| 113 |
| 114 private: |
| 115 base::ScopedFD read_fd_; |
| 116 std::unique_ptr<base::FileDescriptorWatcher::Controller> fd_watcher_; |
| 117 cc::RingBuffer<std::string, kTraceEventBufferSize> ring_buffer_; |
| 118 // NOTE: Weak pointers must be invalidated before all other member variables |
| 119 // so it must be the last member. |
| 120 base::WeakPtrFactory<ArcTracingReader> weak_ptr_factory_; |
| 121 |
| 122 DISALLOW_COPY_AND_ASSIGN(ArcTracingReader); |
| 123 }; |
25 | 124 |
26 class ArcTracingAgentImpl : public ArcTracingAgent { | 125 class ArcTracingAgentImpl : public ArcTracingAgent { |
27 public: | 126 public: |
28 // base::trace_event::TracingAgent overrides: | 127 // base::trace_event::TracingAgent overrides: |
29 std::string GetTracingAgentName() override { return kArcTracingAgentName; } | 128 std::string GetTracingAgentName() override { return kArcTracingAgentName; } |
30 | 129 |
31 std::string GetTraceEventLabel() override { return kArcTraceLabel; } | 130 std::string GetTraceEventLabel() override { return kArcTraceLabel; } |
32 | 131 |
33 void StartAgentTracing(const base::trace_event::TraceConfig& trace_config, | 132 void StartAgentTracing(const base::trace_event::TraceConfig& trace_config, |
34 const StartAgentTracingCallback& callback) override { | 133 const StartAgentTracingCallback& callback) override { |
35 DCHECK(thread_checker_.CalledOnValidThread()); | 134 DCHECK_CURRENTLY_ON(BrowserThread::UI); |
| 135 |
36 // delegate_ may be nullptr if ARC is not enabled on the system. In such | 136 // delegate_ may be nullptr if ARC is not enabled on the system. In such |
37 // case, simply do nothing. | 137 // case, simply do nothing. |
38 if (!delegate_) { | 138 bool success = (delegate_ != nullptr); |
| 139 |
| 140 base::ScopedFD write_fd, read_fd; |
| 141 success = success && CreateSocketPair(&read_fd, &write_fd); |
| 142 |
| 143 if (!success) { |
39 // Use PostTask as the convention of TracingAgent. The caller expects | 144 // Use PostTask as the convention of TracingAgent. The caller expects |
40 // callback to be called after this function returns. | 145 // callback to be called after this function returns. |
41 base::ThreadTaskRunnerHandle::Get()->PostTask( | 146 base::ThreadTaskRunnerHandle::Get()->PostTask( |
42 FROM_HERE, base::Bind(callback, GetTracingAgentName(), false)); | 147 FROM_HERE, base::Bind(callback, GetTracingAgentName(), false)); |
43 return; | 148 return; |
44 } | 149 } |
45 | 150 |
46 delegate_->StartTracing(trace_config, | 151 BrowserThread::PostTask( |
| 152 BrowserThread::IO, FROM_HERE, |
| 153 base::Bind(&ArcTracingReader::StartTracing, reader_.GetWeakPtr(), |
| 154 base::Passed(&read_fd))); |
| 155 |
| 156 delegate_->StartTracing(trace_config, std::move(write_fd), |
47 base::Bind(callback, GetTracingAgentName())); | 157 base::Bind(callback, GetTracingAgentName())); |
48 } | 158 } |
49 | 159 |
50 void StopAgentTracing(const StopAgentTracingCallback& callback) override { | 160 void StopAgentTracing(const StopAgentTracingCallback& callback) override { |
51 DCHECK(thread_checker_.CalledOnValidThread()); | 161 DCHECK_CURRENTLY_ON(BrowserThread::UI); |
52 if (delegate_) | |
53 delegate_->StopTracing(base::Bind(OnStopTracing)); | |
54 | 162 |
55 // Trace data is collect via systrace (debugd) in dev-mode. Simply | 163 if (is_stopping_) { |
56 // return empty data here. | 164 DLOG(WARNING) << "Already working on stopping ArcTracingAgent."; |
57 std::string no_data; | 165 return; |
58 base::ThreadTaskRunnerHandle::Get()->PostTask( | 166 } |
59 FROM_HERE, | 167 is_stopping_ = true; |
60 base::Bind(callback, GetTracingAgentName(), GetTraceEventLabel(), | 168 if (delegate_) { |
61 base::RefCountedString::TakeString(&no_data))); | 169 delegate_->StopTracing( |
| 170 base::Bind(&ArcTracingAgentImpl::OnArcTracingStopped, |
| 171 weak_ptr_factory_.GetWeakPtr(), callback)); |
| 172 } |
62 } | 173 } |
63 | 174 |
64 // ArcTracingAgent overrides: | 175 // ArcTracingAgent overrides: |
65 void SetDelegate(Delegate* delegate) override { | 176 void SetDelegate(Delegate* delegate) override { |
66 DCHECK(thread_checker_.CalledOnValidThread()); | 177 DCHECK_CURRENTLY_ON(BrowserThread::UI); |
67 delegate_ = delegate; | 178 delegate_ = delegate; |
68 } | 179 } |
69 | 180 |
70 static ArcTracingAgentImpl* GetInstance() { | 181 static ArcTracingAgentImpl* GetInstance() { |
71 return base::Singleton<ArcTracingAgentImpl>::get(); | 182 return base::Singleton<ArcTracingAgentImpl>::get(); |
72 } | 183 } |
73 | 184 |
74 private: | 185 private: |
75 // This allows constructor and destructor to be private and usable only | 186 // This allows constructor and destructor to be private and usable only |
76 // by the Singleton class. | 187 // by the Singleton class. |
77 friend struct base::DefaultSingletonTraits<ArcTracingAgentImpl>; | 188 friend struct base::DefaultSingletonTraits<ArcTracingAgentImpl>; |
78 | 189 |
79 ArcTracingAgentImpl() = default; | 190 ArcTracingAgentImpl() : weak_ptr_factory_(this) {} |
| 191 |
80 ~ArcTracingAgentImpl() override = default; | 192 ~ArcTracingAgentImpl() override = default; |
81 | 193 |
| 194 void OnArcTracingStopped(const StopAgentTracingCallback& callback, |
| 195 bool success) { |
| 196 DCHECK_CURRENTLY_ON(BrowserThread::UI); |
| 197 if (!success) { |
| 198 DLOG(WARNING) << "Failed to stop ARC tracing."; |
| 199 callback.Run(GetTracingAgentName(), GetTraceEventLabel(), |
| 200 new base::RefCountedString()); |
| 201 is_stopping_ = false; |
| 202 return; |
| 203 } |
| 204 BrowserThread::PostTask( |
| 205 BrowserThread::IO, FROM_HERE, |
| 206 base::Bind(&ArcTracingReader::StopTracing, reader_.GetWeakPtr(), |
| 207 base::Bind(&ArcTracingAgentImpl::OnTracingReaderStopped, |
| 208 weak_ptr_factory_.GetWeakPtr(), callback))); |
| 209 } |
| 210 |
| 211 void OnTracingReaderStopped( |
| 212 const StopAgentTracingCallback& callback, |
| 213 const scoped_refptr<base::RefCountedString>& data) { |
| 214 DCHECK_CURRENTLY_ON(BrowserThread::UI); |
| 215 callback.Run(GetTracingAgentName(), GetTraceEventLabel(), data); |
| 216 is_stopping_ = false; |
| 217 } |
| 218 |
82 Delegate* delegate_ = nullptr; // Owned by ArcServiceLauncher. | 219 Delegate* delegate_ = nullptr; // Owned by ArcServiceLauncher. |
83 base::ThreadChecker thread_checker_; | 220 // We use |reader_.GetWeakPtr()| when binding callbacks with its functions. |
| 221 // Notes that the weak pointer returned by it can only be deferenced or |
| 222 // invalided in the same task runner to avoid racing condition. The |
| 223 // destruction of |reader_| is also a source of invalidation. However, we're |
| 224 // lucky as we're using |ArcTracingAgentImpl| as a singleton, the |
| 225 // destruction is always performed after all MessageLoops are destroyed, and |
| 226 // thus there are no race conditions in such situation. |
| 227 ArcTracingReader reader_; |
| 228 bool is_stopping_ = false; |
| 229 // NOTE: Weak pointers must be invalidated before all other member variables |
| 230 // so it must be the last member. |
| 231 base::WeakPtrFactory<ArcTracingAgentImpl> weak_ptr_factory_; |
84 | 232 |
85 DISALLOW_COPY_AND_ASSIGN(ArcTracingAgentImpl); | 233 DISALLOW_COPY_AND_ASSIGN(ArcTracingAgentImpl); |
86 }; | 234 }; |
87 | 235 |
88 } // namespace | 236 } // namespace |
89 | 237 |
90 // static | 238 // static |
91 ArcTracingAgent* ArcTracingAgent::GetInstance() { | 239 ArcTracingAgent* ArcTracingAgent::GetInstance() { |
92 return ArcTracingAgentImpl::GetInstance(); | 240 return ArcTracingAgentImpl::GetInstance(); |
93 } | 241 } |
94 | 242 |
95 ArcTracingAgent::ArcTracingAgent() = default; | 243 ArcTracingAgent::ArcTracingAgent() = default; |
96 ArcTracingAgent::~ArcTracingAgent() = default; | 244 ArcTracingAgent::~ArcTracingAgent() = default; |
97 | 245 |
98 ArcTracingAgent::Delegate::~Delegate() = default; | 246 ArcTracingAgent::Delegate::~Delegate() = default; |
99 | 247 |
100 } // namespace content | 248 } // namespace content |
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