1/*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "inplace_sampler_lib.h"
18
19#include <inttypes.h>
20#include <pthread.h>
21#include <signal.h>
22#include <stdio.h>
23#include <stdlib.h>
24#include <string.h>
25#include <sys/syscall.h>
26#include <sys/ucontext.h>
27#include <unistd.h>
28
29#include <map>
30#include <memory>
31#include <queue>
32#include <set>
33#include <string>
34#include <unordered_map>
35
36#include <android-base/logging.h>
37#include <android-base/macros.h>
38#include <backtrace/Backtrace.h>
39#define LOG_TAG "InplaceSampler"
40#include <log/log.h>
41
42#include "environment.h"
43#include "UnixSocket.h"
44#include "utils.h"
45
46#define DEFAULT_SIGNO  SIGRTMAX
47static constexpr int DEFAULT_SAMPLE_FREQ = 4000;
48static constexpr int CHECK_THREADS_INTERVAL_IN_MS = 200;
49
50namespace {
51
52struct ThreadInfo {
53  std::string name;
54};
55
56// SampleManager controls the whole sampling process:
57//   Read commands from simpleperf
58//   Set up timers to send signals for each profiled thread regularly.
59//   Send thread info and map info to simpleperf.
60class SampleManager {
61 public:
62  SampleManager(std::unique_ptr<UnixSocketConnection> conn) : conn_(std::move(conn)),
63      tid_(gettid()), signo_(DEFAULT_SIGNO), sample_freq_(DEFAULT_SAMPLE_FREQ),
64      sample_period_in_ns_(0), dump_callchain_(false), monitor_all_threads_(true) {
65  }
66  void Run();
67
68 private:
69  bool HandleMessage(const UnixSocketMessage& msg);
70  bool ParseStartProfilingMessage(const UnixSocketMessage& msg);
71  bool SendStartProfilingReplyMessage(bool ok);
72  bool StartProfiling();
73  bool InstallSignalHandler();
74  bool CheckThreads();
75  bool CheckThreadNameChange(uint64_t timestamp);
76  bool CheckMapChange(uint64_t timestamp);
77  void SendThreadMapInfo();
78  void SendFakeSampleRecord();
79
80  std::unique_ptr<UnixSocketConnection> conn_;
81
82  int tid_;
83  int signo_;
84  uint32_t sample_freq_;
85  uint32_t sample_period_in_ns_;
86  bool dump_callchain_;
87  bool monitor_all_threads_;
88  std::set<int> monitor_tid_filter_;
89  std::map<int, ThreadInfo> threads_;
90  std::map<uint64_t, ThreadMmap> maps_;
91  std::queue<std::unique_ptr<char[]>> thread_map_info_q_;
92
93  IOEventLoop loop_;
94};
95
96void SampleManager::Run() {
97  auto read_callback = [&](const UnixSocketMessage& msg) {
98    return HandleMessage(msg);
99  };
100  auto close_callback = [&]() {
101    return loop_.ExitLoop();
102  };
103  if (!conn_->PrepareForIO(loop_, read_callback, close_callback)) {
104    return;
105  }
106  loop_.RunLoop();
107}
108
109bool SampleManager::HandleMessage(const UnixSocketMessage& msg) {
110  if (msg.type == START_PROFILING) {
111    if (!ParseStartProfilingMessage(msg)) {
112      if (!SendStartProfilingReplyMessage(false)) {
113        return false;
114      }
115      return conn_->NoMoreMessage();
116    }
117    if (!SendStartProfilingReplyMessage(true)) {
118      return false;
119    }
120    return StartProfiling();
121  }
122  if (msg.type == END_PROFILING) {
123    // Close connection after clearing send buffer.
124    return conn_->NoMoreMessage();
125  }
126  LOG(ERROR) << "Unexpected msg type: " << msg.type;
127  return false;
128}
129
130bool SampleManager::ParseStartProfilingMessage(const UnixSocketMessage& msg) {
131  char* option = const_cast<char*>(msg.data);
132  while (option != nullptr && *option != '\0') {
133    char* next_option = strchr(option, ' ');
134    if (next_option != nullptr) {
135      *next_option++ = '\0';
136    }
137    char* equal_op = strchr(option, '=');
138    if (equal_op != nullptr) {
139      char* key = option;
140      *equal_op = '\0';
141      char* value = equal_op + 1;
142      if (strcmp(key, "freq") == 0) {
143        sample_freq_ = atoi(value);
144      } else if (strcmp(key, "signal") == 0) {
145        signo_ = atoi(value);
146      } else if (strcmp(key, "tids") == 0) {
147        monitor_all_threads_ = false;
148        while (*value != '\0') {
149          int tid = static_cast<int>(strtol(value, &value, 10));
150          monitor_tid_filter_.insert(tid);
151          if (*value == ',') {
152            ++value;
153          }
154        }
155      } else if (strcmp(key, "dump_callchain") == 0) {
156        dump_callchain_ = (strcmp(value, "1") == 0);
157      }
158    }
159    option = next_option;
160  }
161  if (sample_freq_ == 0 || sample_freq_ > 1000000000) {
162    LOG(ERROR) << "Unexpected sample_freq: " << sample_freq_;
163    return false;
164  }
165  if (sample_freq_ == 1) {
166    sample_period_in_ns_ = 999999999;
167  } else {
168    sample_period_in_ns_ = 1000000000 / sample_freq_;
169  }
170  return true;
171}
172
173bool SampleManager::SendStartProfilingReplyMessage(bool ok) {
174  const char* s = ok ? "ok" : "error";
175  size_t size = sizeof(UnixSocketMessage) + strlen(s) + 1;
176  std::unique_ptr<char[]> data(new char[size]);
177  UnixSocketMessage* msg = reinterpret_cast<UnixSocketMessage*>(data.get());
178  msg->len = size;
179  msg->type = START_PROFILING_REPLY;
180  strcpy(msg->data, s);
181  return conn_->SendMessage(*msg, true);
182}
183
184bool SampleManager::StartProfiling() {
185  if (!InstallSignalHandler()) {
186    return false;
187  }
188  if (!CheckThreads()) {
189    return false;
190  }
191  timeval tv;
192  tv.tv_sec = CHECK_THREADS_INTERVAL_IN_MS / 1000;
193  tv.tv_usec = CHECK_THREADS_INTERVAL_IN_MS % 1000 * 1000;
194  return loop_.AddPeriodicEvent(tv, [&]() {
195    return CheckThreads();
196  });
197}
198
199bool SampleManager::InstallSignalHandler() {
200  return true;
201}
202
203bool SampleManager::CheckThreads() {
204  uint64_t timestamp = GetSystemClock();
205  if (!CheckMapChange(timestamp)) {
206    return false;
207  }
208  if (!CheckThreadNameChange(timestamp)) {
209    return false;
210  }
211  SendThreadMapInfo();
212  // For testing.
213  SendFakeSampleRecord();
214  return true;
215}
216
217bool SampleManager::CheckThreadNameChange(uint64_t timestamp) {
218  std::vector<pid_t> tids = GetThreadsInProcess(getpid());
219  std::map<pid_t, std::string> current;
220  for (auto& tid : tids) {
221    if (tid == tid_) {
222      // Skip sample thread.
223      continue;
224    }
225    if (monitor_all_threads_ || monitor_tid_filter_.find(tid) != monitor_tid_filter_.end()) {
226      std::string name;
227      if (GetThreadName(tid, &name)) {
228        current[tid] = name;
229      }
230    }
231  }
232  // Check new threads or threads with new names.
233  for (auto& pair : current) {
234    pid_t tid = pair.first;
235    auto it = threads_.find(tid);
236    if (it == threads_.end() || it->second.name != pair.second) {
237      threads_[tid].name = pair.second;
238      size_t size = sizeof(UnixSocketMessage) + sizeof(uint64_t) + sizeof(uint32_t) +
239          pair.second.size() + 1;
240      std::unique_ptr<char[]> data(new char[size]);
241      UnixSocketMessage* msg = reinterpret_cast<UnixSocketMessage*>(data.get());
242      msg->len = size;
243      msg->type = THREAD_INFO;
244      char* p = msg->data;
245      MoveToBinaryFormat(timestamp, p);
246      MoveToBinaryFormat(static_cast<uint32_t>(tid), p);
247      MoveToBinaryFormat(pair.second.c_str(), pair.second.size() + 1, p);
248      thread_map_info_q_.push(std::move(data));
249    }
250  }
251  // Check deleted threads.
252  for (auto it = threads_.begin(); it != threads_.end();) {
253    int tid = it->first;
254    if (current.find(tid) == current.end()) {
255      it = threads_.erase(it);
256    } else {
257      ++it;
258    }
259  }
260  return true;
261}
262
263bool SampleManager::CheckMapChange(uint64_t timestamp) {
264  std::vector<ThreadMmap> maps;
265  if (!GetThreadMmapsInProcess(getpid(), &maps)) {
266    return false;
267  }
268  // Check new maps or changed maps.
269  for (auto& map : maps) {
270    if (!map.executable) {
271      continue;
272    }
273    auto it = maps_.find(map.start_addr);
274    if (it == maps_.end() || it->second.len != map.len || it->second.pgoff != map.pgoff ||
275        it->second.name != map.name) {
276      maps_[map.start_addr] = map;
277      size_t size = sizeof(UnixSocketMessage) + sizeof(uint64_t) * 4 + map.name.size() + 1;
278      std::unique_ptr<char[]> data(new char[size]);
279      UnixSocketMessage* msg = reinterpret_cast<UnixSocketMessage*>(data.get());
280      msg->len = size;
281      msg->type = MAP_INFO;
282      char* p = msg->data;
283      MoveToBinaryFormat(timestamp, p);
284      MoveToBinaryFormat(map.start_addr, p);
285      MoveToBinaryFormat(map.len, p);
286      MoveToBinaryFormat(map.pgoff, p);
287      MoveToBinaryFormat(map.name.c_str(), map.name.size() + 1, p);
288      thread_map_info_q_.push(std::move(data));
289    }
290  }
291  return true;
292}
293
294void SampleManager::SendThreadMapInfo() {
295  while (!thread_map_info_q_.empty()) {
296    auto& data = thread_map_info_q_.front();
297    UnixSocketMessage* msg = reinterpret_cast<UnixSocketMessage*>(data.get());
298    if (!conn_->SendMessage(*msg, false)) {
299      break;
300    }
301    thread_map_info_q_.pop();
302  }
303}
304
305static void FakeFunction() {
306}
307
308void SampleManager::SendFakeSampleRecord() {
309  size_t size = sizeof(UnixSocketMessage) + sizeof(uint64_t) * 2 + sizeof(uint32_t) *  3;
310  std::unique_ptr<char[]> data(new char[size]);
311  UnixSocketMessage* msg = reinterpret_cast<UnixSocketMessage*>(data.get());
312  uint64_t ip = static_cast<uint64_t>(reinterpret_cast<uintptr_t>(&FakeFunction));
313  msg->len = size;
314  msg->type = SAMPLE_INFO;
315  char* p = msg->data;
316  MoveToBinaryFormat(GetSystemClock(), p);
317  MoveToBinaryFormat(static_cast<uint32_t>(tid_), p);
318  MoveToBinaryFormat(1u, p);
319  MoveToBinaryFormat(1u, p);
320  MoveToBinaryFormat(ip, p);
321  conn_->SendMessage(*msg, false);
322}
323
324static void* CommunicationThread(void*) {
325  pthread_setname_np(pthread_self(), "inplace_sampler");
326  std::string server_path = "inplace_sampler_server_" + std::to_string(getpid());
327  std::unique_ptr<UnixSocketServer> server = UnixSocketServer::Create(server_path, true);
328  if (server == nullptr) {
329    LOG(ERROR) << "failed to create server at path " << server_path;
330    return nullptr;
331  }
332  LOG(INFO) << "Create inplace_sampler_server at " << server_path;
333  while (true) {
334    std::unique_ptr<UnixSocketConnection> conn = server->AcceptConnection();
335    if (conn == nullptr) {
336      break;
337    }
338    SampleManager manager(std::move(conn));
339    manager.Run();
340  }
341  return nullptr;
342}
343
344__attribute__((constructor)) void InitSampler() {
345  pthread_attr_t attr;
346  if (pthread_attr_init(&attr) != 0) {
347    LOG(ERROR) << "pthread_attr_init failed";
348    return;
349  }
350  if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) != 0) {
351    LOG(ERROR) << "pthread_attr_setdetachstate failed";
352    return;
353  }
354  pthread_t thread;
355  if (pthread_create(&thread, &attr, CommunicationThread, nullptr) != 0) {
356    LOG(ERROR) << "pthread_create failed";
357    return;
358  }
359  pthread_attr_destroy(&attr);
360}
361
362}  // namespace
363