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
47 static constexpr int DEFAULT_SAMPLE_FREQ = 4000;
48 static constexpr int CHECK_THREADS_INTERVAL_IN_MS = 200;
49
50 namespace {
51
52 struct 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.
60 class SampleManager {
61 public:
SampleManager(std::unique_ptr<UnixSocketConnection> conn)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
Run()96 void 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
HandleMessage(const UnixSocketMessage & msg)109 bool 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
ParseStartProfilingMessage(const UnixSocketMessage & msg)130 bool 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
SendStartProfilingReplyMessage(bool ok)173 bool 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
StartProfiling()184 bool 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
InstallSignalHandler()199 bool SampleManager::InstallSignalHandler() {
200 return true;
201 }
202
CheckThreads()203 bool 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
CheckThreadNameChange(uint64_t timestamp)217 bool 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
CheckMapChange(uint64_t timestamp)263 bool 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.prot & PROT_EXEC)) {
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
SendThreadMapInfo()294 void 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
FakeFunction()305 static void FakeFunction() {
306 }
307
SendFakeSampleRecord()308 void 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
CommunicationThread(void *)324 static 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
InitSampler()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