1 //===-- Communication.cpp ---------------------------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "lldb/Core/Communication.h" 10 11 #include "lldb/Host/HostThread.h" 12 #include "lldb/Host/ThreadLauncher.h" 13 #include "lldb/Utility/Connection.h" 14 #include "lldb/Utility/ConstString.h" 15 #include "lldb/Utility/Event.h" 16 #include "lldb/Utility/Listener.h" 17 #include "lldb/Utility/Log.h" 18 #include "lldb/Utility/Logging.h" 19 #include "lldb/Utility/Status.h" 20 21 #include "llvm/ADT/None.h" 22 #include "llvm/ADT/Optional.h" 23 #include "llvm/Support/Compiler.h" 24 25 #include <algorithm> 26 #include <chrono> 27 #include <cstring> 28 #include <memory> 29 30 #include <errno.h> 31 #include <inttypes.h> 32 #include <stdio.h> 33 34 using namespace lldb; 35 using namespace lldb_private; 36 37 ConstString &Communication::GetStaticBroadcasterClass() { 38 static ConstString class_name("lldb.communication"); 39 return class_name; 40 } 41 42 Communication::Communication(const char *name) 43 : Broadcaster(nullptr, name), m_connection_sp(), 44 m_read_thread_enabled(false), m_read_thread_did_exit(false), m_bytes(), 45 m_bytes_mutex(), m_write_mutex(), m_synchronize_mutex(), 46 m_callback(nullptr), m_callback_baton(nullptr), m_close_on_eof(true) 47 48 { 49 lldb_private::LogIfAnyCategoriesSet( 50 LIBLLDB_LOG_OBJECT | LIBLLDB_LOG_COMMUNICATION, 51 "%p Communication::Communication (name = %s)", this, name); 52 53 SetEventName(eBroadcastBitDisconnected, "disconnected"); 54 SetEventName(eBroadcastBitReadThreadGotBytes, "got bytes"); 55 SetEventName(eBroadcastBitReadThreadDidExit, "read thread did exit"); 56 SetEventName(eBroadcastBitReadThreadShouldExit, "read thread should exit"); 57 SetEventName(eBroadcastBitPacketAvailable, "packet available"); 58 SetEventName(eBroadcastBitNoMorePendingInput, "no more pending input"); 59 60 CheckInWithManager(); 61 } 62 63 Communication::~Communication() { 64 lldb_private::LogIfAnyCategoriesSet( 65 LIBLLDB_LOG_OBJECT | LIBLLDB_LOG_COMMUNICATION, 66 "%p Communication::~Communication (name = %s)", this, 67 GetBroadcasterName().AsCString()); 68 Clear(); 69 } 70 71 void Communication::Clear() { 72 SetReadThreadBytesReceivedCallback(nullptr, nullptr); 73 Disconnect(nullptr); 74 StopReadThread(nullptr); 75 } 76 77 ConnectionStatus Communication::Connect(const char *url, Status *error_ptr) { 78 Clear(); 79 80 lldb_private::LogIfAnyCategoriesSet(LIBLLDB_LOG_COMMUNICATION, 81 "%p Communication::Connect (url = %s)", 82 this, url); 83 84 lldb::ConnectionSP connection_sp(m_connection_sp); 85 if (connection_sp) 86 return connection_sp->Connect(url, error_ptr); 87 if (error_ptr) 88 error_ptr->SetErrorString("Invalid connection."); 89 return eConnectionStatusNoConnection; 90 } 91 92 ConnectionStatus Communication::Disconnect(Status *error_ptr) { 93 lldb_private::LogIfAnyCategoriesSet(LIBLLDB_LOG_COMMUNICATION, 94 "%p Communication::Disconnect ()", this); 95 96 lldb::ConnectionSP connection_sp(m_connection_sp); 97 if (connection_sp) { 98 ConnectionStatus status = connection_sp->Disconnect(error_ptr); 99 // We currently don't protect connection_sp with any mutex for multi- 100 // threaded environments. So lets not nuke our connection class without 101 // putting some multi-threaded protections in. We also probably don't want 102 // to pay for the overhead it might cause if every time we access the 103 // connection we have to take a lock. 104 // 105 // This unique pointer will cleanup after itself when this object goes 106 // away, so there is no need to currently have it destroy itself 107 // immediately upon disconnect. 108 // connection_sp.reset(); 109 return status; 110 } 111 return eConnectionStatusNoConnection; 112 } 113 114 bool Communication::IsConnected() const { 115 lldb::ConnectionSP connection_sp(m_connection_sp); 116 return (connection_sp ? connection_sp->IsConnected() : false); 117 } 118 119 bool Communication::HasConnection() const { 120 return m_connection_sp.get() != nullptr; 121 } 122 123 size_t Communication::Read(void *dst, size_t dst_len, 124 const Timeout<std::micro> &timeout, 125 ConnectionStatus &status, Status *error_ptr) { 126 Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_COMMUNICATION); 127 LLDB_LOG( 128 log, 129 "this = {0}, dst = {1}, dst_len = {2}, timeout = {3}, connection = {4}", 130 this, dst, dst_len, timeout, m_connection_sp.get()); 131 132 if (m_read_thread_enabled) { 133 // We have a dedicated read thread that is getting data for us 134 size_t cached_bytes = GetCachedBytes(dst, dst_len); 135 if (cached_bytes > 0 || (timeout && timeout->count() == 0)) { 136 status = eConnectionStatusSuccess; 137 return cached_bytes; 138 } 139 140 if (!m_connection_sp) { 141 if (error_ptr) 142 error_ptr->SetErrorString("Invalid connection."); 143 status = eConnectionStatusNoConnection; 144 return 0; 145 } 146 147 ListenerSP listener_sp(Listener::MakeListener("Communication::Read")); 148 listener_sp->StartListeningForEvents( 149 this, eBroadcastBitReadThreadGotBytes | eBroadcastBitReadThreadDidExit); 150 EventSP event_sp; 151 while (listener_sp->GetEvent(event_sp, timeout)) { 152 const uint32_t event_type = event_sp->GetType(); 153 if (event_type & eBroadcastBitReadThreadGotBytes) { 154 return GetCachedBytes(dst, dst_len); 155 } 156 157 if (event_type & eBroadcastBitReadThreadDidExit) { 158 if (GetCloseOnEOF()) 159 Disconnect(nullptr); 160 break; 161 } 162 } 163 return 0; 164 } 165 166 // We aren't using a read thread, just read the data synchronously in this 167 // thread. 168 return ReadFromConnection(dst, dst_len, timeout, status, error_ptr); 169 } 170 171 size_t Communication::Write(const void *src, size_t src_len, 172 ConnectionStatus &status, Status *error_ptr) { 173 lldb::ConnectionSP connection_sp(m_connection_sp); 174 175 std::lock_guard<std::mutex> guard(m_write_mutex); 176 lldb_private::LogIfAnyCategoriesSet( 177 LIBLLDB_LOG_COMMUNICATION, 178 "%p Communication::Write (src = %p, src_len = %" PRIu64 179 ") connection = %p", 180 this, src, (uint64_t)src_len, connection_sp.get()); 181 182 if (connection_sp) 183 return connection_sp->Write(src, src_len, status, error_ptr); 184 185 if (error_ptr) 186 error_ptr->SetErrorString("Invalid connection."); 187 status = eConnectionStatusNoConnection; 188 return 0; 189 } 190 191 bool Communication::StartReadThread(Status *error_ptr) { 192 if (error_ptr) 193 error_ptr->Clear(); 194 195 if (m_read_thread.IsJoinable()) 196 return true; 197 198 lldb_private::LogIfAnyCategoriesSet( 199 LIBLLDB_LOG_COMMUNICATION, "%p Communication::StartReadThread ()", this); 200 201 char thread_name[1024]; 202 snprintf(thread_name, sizeof(thread_name), "<lldb.comm.%s>", 203 GetBroadcasterName().AsCString()); 204 205 m_read_thread_enabled = true; 206 m_read_thread_did_exit = false; 207 auto maybe_thread = ThreadLauncher::LaunchThread( 208 thread_name, Communication::ReadThread, this); 209 if (maybe_thread) { 210 m_read_thread = *maybe_thread; 211 } else { 212 if (error_ptr) 213 *error_ptr = Status(maybe_thread.takeError()); 214 else { 215 LLDB_LOG(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST), 216 "failed to launch host thread: {}", 217 llvm::toString(maybe_thread.takeError())); 218 } 219 } 220 221 if (!m_read_thread.IsJoinable()) 222 m_read_thread_enabled = false; 223 224 return m_read_thread_enabled; 225 } 226 227 bool Communication::StopReadThread(Status *error_ptr) { 228 if (!m_read_thread.IsJoinable()) 229 return true; 230 231 lldb_private::LogIfAnyCategoriesSet( 232 LIBLLDB_LOG_COMMUNICATION, "%p Communication::StopReadThread ()", this); 233 234 m_read_thread_enabled = false; 235 236 BroadcastEvent(eBroadcastBitReadThreadShouldExit, nullptr); 237 238 // error = m_read_thread.Cancel(); 239 240 Status error = m_read_thread.Join(nullptr); 241 return error.Success(); 242 } 243 244 bool Communication::JoinReadThread(Status *error_ptr) { 245 if (!m_read_thread.IsJoinable()) 246 return true; 247 248 Status error = m_read_thread.Join(nullptr); 249 return error.Success(); 250 } 251 252 size_t Communication::GetCachedBytes(void *dst, size_t dst_len) { 253 std::lock_guard<std::recursive_mutex> guard(m_bytes_mutex); 254 if (!m_bytes.empty()) { 255 // If DST is nullptr and we have a thread, then return the number of bytes 256 // that are available so the caller can call again 257 if (dst == nullptr) 258 return m_bytes.size(); 259 260 const size_t len = std::min<size_t>(dst_len, m_bytes.size()); 261 262 ::memcpy(dst, m_bytes.c_str(), len); 263 m_bytes.erase(m_bytes.begin(), m_bytes.begin() + len); 264 265 return len; 266 } 267 return 0; 268 } 269 270 void Communication::AppendBytesToCache(const uint8_t *bytes, size_t len, 271 bool broadcast, 272 ConnectionStatus status) { 273 lldb_private::LogIfAnyCategoriesSet( 274 LIBLLDB_LOG_COMMUNICATION, 275 "%p Communication::AppendBytesToCache (src = %p, src_len = %" PRIu64 276 ", broadcast = %i)", 277 this, bytes, (uint64_t)len, broadcast); 278 if ((bytes == nullptr || len == 0) && 279 (status != lldb::eConnectionStatusEndOfFile)) 280 return; 281 if (m_callback) { 282 // If the user registered a callback, then call it and do not broadcast 283 m_callback(m_callback_baton, bytes, len); 284 } else if (bytes != nullptr && len > 0) { 285 std::lock_guard<std::recursive_mutex> guard(m_bytes_mutex); 286 m_bytes.append((const char *)bytes, len); 287 if (broadcast) 288 BroadcastEventIfUnique(eBroadcastBitReadThreadGotBytes); 289 } 290 } 291 292 size_t Communication::ReadFromConnection(void *dst, size_t dst_len, 293 const Timeout<std::micro> &timeout, 294 ConnectionStatus &status, 295 Status *error_ptr) { 296 lldb::ConnectionSP connection_sp(m_connection_sp); 297 if (connection_sp) 298 return connection_sp->Read(dst, dst_len, timeout, status, error_ptr); 299 300 if (error_ptr) 301 error_ptr->SetErrorString("Invalid connection."); 302 status = eConnectionStatusNoConnection; 303 return 0; 304 } 305 306 bool Communication::ReadThreadIsRunning() { return m_read_thread_enabled; } 307 308 lldb::thread_result_t Communication::ReadThread(lldb::thread_arg_t p) { 309 Communication *comm = (Communication *)p; 310 311 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_COMMUNICATION)); 312 313 if (log) 314 log->Printf("%p Communication::ReadThread () thread starting...", p); 315 316 uint8_t buf[1024]; 317 318 Status error; 319 ConnectionStatus status = eConnectionStatusSuccess; 320 bool done = false; 321 while (!done && comm->m_read_thread_enabled) { 322 size_t bytes_read = comm->ReadFromConnection( 323 buf, sizeof(buf), std::chrono::seconds(5), status, &error); 324 if (bytes_read > 0) 325 comm->AppendBytesToCache(buf, bytes_read, true, status); 326 else if ((bytes_read == 0) && status == eConnectionStatusEndOfFile) { 327 if (comm->GetCloseOnEOF()) 328 comm->Disconnect(); 329 comm->AppendBytesToCache(buf, bytes_read, true, status); 330 } 331 332 switch (status) { 333 case eConnectionStatusSuccess: 334 break; 335 336 case eConnectionStatusEndOfFile: 337 done = true; 338 break; 339 case eConnectionStatusError: // Check GetError() for details 340 if (error.GetType() == eErrorTypePOSIX && error.GetError() == EIO) { 341 // EIO on a pipe is usually caused by remote shutdown 342 comm->Disconnect(); 343 done = true; 344 } 345 if (error.Fail()) 346 LLDB_LOG(log, "error: {0}, status = {1}", error, 347 Communication::ConnectionStatusAsCString(status)); 348 break; 349 case eConnectionStatusInterrupted: // Synchronization signal from 350 // SynchronizeWithReadThread() 351 // The connection returns eConnectionStatusInterrupted only when there is 352 // no input pending to be read, so we can signal that. 353 comm->BroadcastEvent(eBroadcastBitNoMorePendingInput); 354 break; 355 case eConnectionStatusNoConnection: // No connection 356 case eConnectionStatusLostConnection: // Lost connection while connected to 357 // a valid connection 358 done = true; 359 LLVM_FALLTHROUGH; 360 case eConnectionStatusTimedOut: // Request timed out 361 if (error.Fail()) 362 LLDB_LOG(log, "error: {0}, status = {1}", error, 363 Communication::ConnectionStatusAsCString(status)); 364 break; 365 } 366 } 367 log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_COMMUNICATION); 368 if (log) 369 log->Printf("%p Communication::ReadThread () thread exiting...", p); 370 371 comm->m_read_thread_did_exit = true; 372 // Let clients know that this thread is exiting 373 comm->BroadcastEvent(eBroadcastBitNoMorePendingInput); 374 comm->BroadcastEvent(eBroadcastBitReadThreadDidExit); 375 return {}; 376 } 377 378 void Communication::SetReadThreadBytesReceivedCallback( 379 ReadThreadBytesReceived callback, void *callback_baton) { 380 m_callback = callback; 381 m_callback_baton = callback_baton; 382 } 383 384 void Communication::SynchronizeWithReadThread() { 385 // Only one thread can do the synchronization dance at a time. 386 std::lock_guard<std::mutex> guard(m_synchronize_mutex); 387 388 // First start listening for the synchronization event. 389 ListenerSP listener_sp( 390 Listener::MakeListener("Communication::SyncronizeWithReadThread")); 391 listener_sp->StartListeningForEvents(this, eBroadcastBitNoMorePendingInput); 392 393 // If the thread is not running, there is no point in synchronizing. 394 if (!m_read_thread_enabled || m_read_thread_did_exit) 395 return; 396 397 // Notify the read thread. 398 m_connection_sp->InterruptRead(); 399 400 // Wait for the synchronization event. 401 EventSP event_sp; 402 listener_sp->GetEvent(event_sp, llvm::None); 403 } 404 405 void Communication::SetConnection(Connection *connection) { 406 Disconnect(nullptr); 407 StopReadThread(nullptr); 408 m_connection_sp.reset(connection); 409 } 410 411 const char * 412 Communication::ConnectionStatusAsCString(lldb::ConnectionStatus status) { 413 switch (status) { 414 case eConnectionStatusSuccess: 415 return "success"; 416 case eConnectionStatusError: 417 return "error"; 418 case eConnectionStatusTimedOut: 419 return "timed out"; 420 case eConnectionStatusNoConnection: 421 return "no connection"; 422 case eConnectionStatusLostConnection: 423 return "lost connection"; 424 case eConnectionStatusEndOfFile: 425 return "end of file"; 426 case eConnectionStatusInterrupted: 427 return "interrupted"; 428 } 429 430 static char unknown_state_string[64]; 431 snprintf(unknown_state_string, sizeof(unknown_state_string), 432 "ConnectionStatus = %i", status); 433 return unknown_state_string; 434 } 435