//===-- GDBRemoteCommunication.cpp ----------------------------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// #include "GDBRemoteCommunication.h" #include #include #include #include #include "lldb/Core/StreamFile.h" #include "lldb/Host/Config.h" #include "lldb/Host/ConnectionFileDescriptor.h" #include "lldb/Host/FileSystem.h" #include "lldb/Host/Host.h" #include "lldb/Host/HostInfo.h" #include "lldb/Host/Pipe.h" #include "lldb/Host/ProcessLaunchInfo.h" #include "lldb/Host/Socket.h" #include "lldb/Host/StringConvert.h" #include "lldb/Host/ThreadLauncher.h" #include "lldb/Host/common/TCPSocket.h" #include "lldb/Host/posix/ConnectionFileDescriptorPosix.h" #include "lldb/Target/Platform.h" #include "lldb/Utility/Event.h" #include "lldb/Utility/FileSpec.h" #include "lldb/Utility/Log.h" #include "lldb/Utility/RegularExpression.h" #include "lldb/Utility/Reproducer.h" #include "lldb/Utility/StreamString.h" #include "llvm/ADT/SmallString.h" #include "llvm/Support/ScopedPrinter.h" #include "ProcessGDBRemoteLog.h" #if defined(__APPLE__) #define DEBUGSERVER_BASENAME "debugserver" #elif defined(_WIN32) #define DEBUGSERVER_BASENAME "lldb-server.exe" #else #define DEBUGSERVER_BASENAME "lldb-server" #endif #if defined(HAVE_LIBCOMPRESSION) #include #endif #if LLVM_ENABLE_ZLIB #include #endif using namespace lldb; using namespace lldb_private; using namespace lldb_private::process_gdb_remote; // GDBRemoteCommunication constructor GDBRemoteCommunication::GDBRemoteCommunication(const char *comm_name, const char *listener_name) : Communication(comm_name), #ifdef LLDB_CONFIGURATION_DEBUG m_packet_timeout(1000), #else m_packet_timeout(1), #endif m_echo_number(0), m_supports_qEcho(eLazyBoolCalculate), m_history(512), m_send_acks(true), m_compression_type(CompressionType::None), m_listen_url() { } // Destructor GDBRemoteCommunication::~GDBRemoteCommunication() { if (IsConnected()) { Disconnect(); } #if defined(HAVE_LIBCOMPRESSION) if (m_decompression_scratch) free (m_decompression_scratch); #endif // Stop the communications read thread which is used to parse all incoming // packets. This function will block until the read thread returns. if (m_read_thread_enabled) StopReadThread(); } char GDBRemoteCommunication::CalculcateChecksum(llvm::StringRef payload) { int checksum = 0; for (char c : payload) checksum += c; return checksum & 255; } size_t GDBRemoteCommunication::SendAck() { Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_PACKETS)); ConnectionStatus status = eConnectionStatusSuccess; char ch = '+'; const size_t bytes_written = Write(&ch, 1, status, nullptr); LLDB_LOGF(log, "<%4" PRIu64 "> send packet: %c", (uint64_t)bytes_written, ch); m_history.AddPacket(ch, GDBRemotePacket::ePacketTypeSend, bytes_written); return bytes_written; } size_t GDBRemoteCommunication::SendNack() { Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_PACKETS)); ConnectionStatus status = eConnectionStatusSuccess; char ch = '-'; const size_t bytes_written = Write(&ch, 1, status, nullptr); LLDB_LOGF(log, "<%4" PRIu64 "> send packet: %c", (uint64_t)bytes_written, ch); m_history.AddPacket(ch, GDBRemotePacket::ePacketTypeSend, bytes_written); return bytes_written; } GDBRemoteCommunication::PacketResult GDBRemoteCommunication::SendPacketNoLock(llvm::StringRef payload) { StreamString packet(0, 4, eByteOrderBig); packet.PutChar('$'); packet.Write(payload.data(), payload.size()); packet.PutChar('#'); packet.PutHex8(CalculcateChecksum(payload)); std::string packet_str = std::string(packet.GetString()); return SendRawPacketNoLock(packet_str); } GDBRemoteCommunication::PacketResult GDBRemoteCommunication::SendRawPacketNoLock(llvm::StringRef packet, bool skip_ack) { if (IsConnected()) { Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_PACKETS)); ConnectionStatus status = eConnectionStatusSuccess; const char *packet_data = packet.data(); const size_t packet_length = packet.size(); size_t bytes_written = Write(packet_data, packet_length, status, nullptr); if (log) { size_t binary_start_offset = 0; if (strncmp(packet_data, "$vFile:pwrite:", strlen("$vFile:pwrite:")) == 0) { const char *first_comma = strchr(packet_data, ','); if (first_comma) { const char *second_comma = strchr(first_comma + 1, ','); if (second_comma) binary_start_offset = second_comma - packet_data + 1; } } // If logging was just enabled and we have history, then dump out what we // have to the log so we get the historical context. The Dump() call that // logs all of the packet will set a boolean so that we don't dump this // more than once if (!m_history.DidDumpToLog()) m_history.Dump(log); if (binary_start_offset) { StreamString strm; // Print non binary data header strm.Printf("<%4" PRIu64 "> send packet: %.*s", (uint64_t)bytes_written, (int)binary_start_offset, packet_data); const uint8_t *p; // Print binary data exactly as sent for (p = (const uint8_t *)packet_data + binary_start_offset; *p != '#'; ++p) strm.Printf("\\x%2.2x", *p); // Print the checksum strm.Printf("%*s", (int)3, p); log->PutString(strm.GetString()); } else LLDB_LOGF(log, "<%4" PRIu64 "> send packet: %.*s", (uint64_t)bytes_written, (int)packet_length, packet_data); } m_history.AddPacket(packet.str(), packet_length, GDBRemotePacket::ePacketTypeSend, bytes_written); if (bytes_written == packet_length) { if (!skip_ack && GetSendAcks()) return GetAck(); else return PacketResult::Success; } else { LLDB_LOGF(log, "error: failed to send packet: %.*s", (int)packet_length, packet_data); } } return PacketResult::ErrorSendFailed; } GDBRemoteCommunication::PacketResult GDBRemoteCommunication::GetAck() { StringExtractorGDBRemote packet; PacketResult result = ReadPacket(packet, GetPacketTimeout(), false); if (result == PacketResult::Success) { if (packet.GetResponseType() == StringExtractorGDBRemote::ResponseType::eAck) return PacketResult::Success; else return PacketResult::ErrorSendAck; } return result; } GDBRemoteCommunication::PacketResult GDBRemoteCommunication::ReadPacketWithOutputSupport( StringExtractorGDBRemote &response, Timeout timeout, bool sync_on_timeout, llvm::function_ref output_callback) { auto result = ReadPacket(response, timeout, sync_on_timeout); while (result == PacketResult::Success && response.IsNormalResponse() && response.PeekChar() == 'O') { response.GetChar(); std::string output; if (response.GetHexByteString(output)) output_callback(output); result = ReadPacket(response, timeout, sync_on_timeout); } return result; } GDBRemoteCommunication::PacketResult GDBRemoteCommunication::ReadPacket(StringExtractorGDBRemote &response, Timeout timeout, bool sync_on_timeout) { if (m_read_thread_enabled) return PopPacketFromQueue(response, timeout); else return WaitForPacketNoLock(response, timeout, sync_on_timeout); } // This function is called when a packet is requested. // A whole packet is popped from the packet queue and returned to the caller. // Packets are placed into this queue from the communication read thread. See // GDBRemoteCommunication::AppendBytesToCache. GDBRemoteCommunication::PacketResult GDBRemoteCommunication::PopPacketFromQueue(StringExtractorGDBRemote &response, Timeout timeout) { auto pred = [&] { return !m_packet_queue.empty() && IsConnected(); }; // lock down the packet queue std::unique_lock lock(m_packet_queue_mutex); if (!timeout) m_condition_queue_not_empty.wait(lock, pred); else { if (!m_condition_queue_not_empty.wait_for(lock, *timeout, pred)) return PacketResult::ErrorReplyTimeout; if (!IsConnected()) return PacketResult::ErrorDisconnected; } // get the front element of the queue response = m_packet_queue.front(); // remove the front element m_packet_queue.pop(); // we got a packet return PacketResult::Success; } GDBRemoteCommunication::PacketResult GDBRemoteCommunication::WaitForPacketNoLock(StringExtractorGDBRemote &packet, Timeout timeout, bool sync_on_timeout) { uint8_t buffer[8192]; Status error; Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_PACKETS)); // Check for a packet from our cache first without trying any reading... if (CheckForPacket(nullptr, 0, packet) != PacketType::Invalid) return PacketResult::Success; bool timed_out = false; bool disconnected = false; while (IsConnected() && !timed_out) { lldb::ConnectionStatus status = eConnectionStatusNoConnection; size_t bytes_read = Read(buffer, sizeof(buffer), timeout, status, &error); LLDB_LOGV(log, "Read(buffer, sizeof(buffer), timeout = {0}, " "status = {1}, error = {2}) => bytes_read = {3}", timeout, Communication::ConnectionStatusAsString(status), error, bytes_read); if (bytes_read > 0) { if (CheckForPacket(buffer, bytes_read, packet) != PacketType::Invalid) return PacketResult::Success; } else { switch (status) { case eConnectionStatusTimedOut: case eConnectionStatusInterrupted: if (sync_on_timeout) { /// Sync the remote GDB server and make sure we get a response that /// corresponds to what we send. /// /// Sends a "qEcho" packet and makes sure it gets the exact packet /// echoed back. If the qEcho packet isn't supported, we send a qC /// packet and make sure we get a valid thread ID back. We use the /// "qC" packet since its response if very unique: is responds with /// "QC%x" where %x is the thread ID of the current thread. This /// makes the response unique enough from other packet responses to /// ensure we are back on track. /// /// This packet is needed after we time out sending a packet so we /// can ensure that we are getting the response for the packet we /// are sending. There are no sequence IDs in the GDB remote /// protocol (there used to be, but they are not supported anymore) /// so if you timeout sending packet "abc", you might then send /// packet "cde" and get the response for the previous "abc" packet. /// Many responses are "OK" or "" (unsupported) or "EXX" (error) so /// many responses for packets can look like responses for other /// packets. So if we timeout, we need to ensure that we can get /// back on track. If we can't get back on track, we must /// disconnect. bool sync_success = false; bool got_actual_response = false; // We timed out, we need to sync back up with the char echo_packet[32]; int echo_packet_len = 0; RegularExpression response_regex; if (m_supports_qEcho == eLazyBoolYes) { echo_packet_len = ::snprintf(echo_packet, sizeof(echo_packet), "qEcho:%u", ++m_echo_number); std::string regex_str = "^"; regex_str += echo_packet; regex_str += "$"; response_regex = RegularExpression(regex_str); } else { echo_packet_len = ::snprintf(echo_packet, sizeof(echo_packet), "qC"); response_regex = RegularExpression(llvm::StringRef("^QC[0-9A-Fa-f]+$")); } PacketResult echo_packet_result = SendPacketNoLock(llvm::StringRef(echo_packet, echo_packet_len)); if (echo_packet_result == PacketResult::Success) { const uint32_t max_retries = 3; uint32_t successful_responses = 0; for (uint32_t i = 0; i < max_retries; ++i) { StringExtractorGDBRemote echo_response; echo_packet_result = WaitForPacketNoLock(echo_response, timeout, false); if (echo_packet_result == PacketResult::Success) { ++successful_responses; if (response_regex.Execute(echo_response.GetStringRef())) { sync_success = true; break; } else if (successful_responses == 1) { // We got something else back as the first successful // response, it probably is the response to the packet we // actually wanted, so copy it over if this is the first // success and continue to try to get the qEcho response packet = echo_response; got_actual_response = true; } } else if (echo_packet_result == PacketResult::ErrorReplyTimeout) continue; // Packet timed out, continue waiting for a response else break; // Something else went wrong getting the packet back, we // failed and are done trying } } // We weren't able to sync back up with the server, we must abort // otherwise all responses might not be from the right packets... if (sync_success) { // We timed out, but were able to recover if (got_actual_response) { // We initially timed out, but we did get a response that came in // before the successful reply to our qEcho packet, so lets say // everything is fine... return PacketResult::Success; } } else { disconnected = true; Disconnect(); } } timed_out = true; break; case eConnectionStatusSuccess: // printf ("status = success but error = %s\n", // error.AsCString("")); break; case eConnectionStatusEndOfFile: case eConnectionStatusNoConnection: case eConnectionStatusLostConnection: case eConnectionStatusError: disconnected = true; Disconnect(); break; } } } packet.Clear(); if (disconnected) return PacketResult::ErrorDisconnected; if (timed_out) return PacketResult::ErrorReplyTimeout; else return PacketResult::ErrorReplyFailed; } bool GDBRemoteCommunication::DecompressPacket() { Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_PACKETS)); if (!CompressionIsEnabled()) return true; size_t pkt_size = m_bytes.size(); // Smallest possible compressed packet is $N#00 - an uncompressed empty // reply, most commonly indicating an unsupported packet. Anything less than // 5 characters, it's definitely not a compressed packet. if (pkt_size < 5) return true; if (m_bytes[0] != '$' && m_bytes[0] != '%') return true; if (m_bytes[1] != 'C' && m_bytes[1] != 'N') return true; size_t hash_mark_idx = m_bytes.find('#'); if (hash_mark_idx == std::string::npos) return true; if (hash_mark_idx + 2 >= m_bytes.size()) return true; if (!::isxdigit(m_bytes[hash_mark_idx + 1]) || !::isxdigit(m_bytes[hash_mark_idx + 2])) return true; size_t content_length = pkt_size - 5; // not counting '$', 'C' | 'N', '#', & the two hex checksum chars size_t content_start = 2; // The first character of the // compressed/not-compressed text of the packet size_t checksum_idx = hash_mark_idx + 1; // The first character of the two hex checksum characters // Normally size_of_first_packet == m_bytes.size() but m_bytes may contain // multiple packets. size_of_first_packet is the size of the initial packet // which we'll replace with the decompressed version of, leaving the rest of // m_bytes unmodified. size_t size_of_first_packet = hash_mark_idx + 3; // Compressed packets ("$C") start with a base10 number which is the size of // the uncompressed payload, then a : and then the compressed data. e.g. // $C1024:#00 Update content_start and content_length to only include // the part of the packet. uint64_t decompressed_bufsize = ULONG_MAX; if (m_bytes[1] == 'C') { size_t i = content_start; while (i < hash_mark_idx && isdigit(m_bytes[i])) i++; if (i < hash_mark_idx && m_bytes[i] == ':') { i++; content_start = i; content_length = hash_mark_idx - content_start; std::string bufsize_str(m_bytes.data() + 2, i - 2 - 1); errno = 0; decompressed_bufsize = ::strtoul(bufsize_str.c_str(), nullptr, 10); if (errno != 0 || decompressed_bufsize == ULONG_MAX) { m_bytes.erase(0, size_of_first_packet); return false; } } } if (GetSendAcks()) { char packet_checksum_cstr[3]; packet_checksum_cstr[0] = m_bytes[checksum_idx]; packet_checksum_cstr[1] = m_bytes[checksum_idx + 1]; packet_checksum_cstr[2] = '\0'; long packet_checksum = strtol(packet_checksum_cstr, nullptr, 16); long actual_checksum = CalculcateChecksum( llvm::StringRef(m_bytes).substr(1, hash_mark_idx - 1)); bool success = packet_checksum == actual_checksum; if (!success) { LLDB_LOGF(log, "error: checksum mismatch: %.*s expected 0x%2.2x, got 0x%2.2x", (int)(pkt_size), m_bytes.c_str(), (uint8_t)packet_checksum, (uint8_t)actual_checksum); } // Send the ack or nack if needed if (!success) { SendNack(); m_bytes.erase(0, size_of_first_packet); return false; } else { SendAck(); } } if (m_bytes[1] == 'N') { // This packet was not compressed -- delete the 'N' character at the start // and the packet may be processed as-is. m_bytes.erase(1, 1); return true; } // Reverse the gdb-remote binary escaping that was done to the compressed // text to guard characters like '$', '#', '}', etc. std::vector unescaped_content; unescaped_content.reserve(content_length); size_t i = content_start; while (i < hash_mark_idx) { if (m_bytes[i] == '}') { i++; unescaped_content.push_back(m_bytes[i] ^ 0x20); } else { unescaped_content.push_back(m_bytes[i]); } i++; } uint8_t *decompressed_buffer = nullptr; size_t decompressed_bytes = 0; if (decompressed_bufsize != ULONG_MAX) { decompressed_buffer = (uint8_t *)malloc(decompressed_bufsize); if (decompressed_buffer == nullptr) { m_bytes.erase(0, size_of_first_packet); return false; } } #if defined(HAVE_LIBCOMPRESSION) if (m_compression_type == CompressionType::ZlibDeflate || m_compression_type == CompressionType::LZFSE || m_compression_type == CompressionType::LZ4 || m_compression_type == CompressionType::LZMA) { compression_algorithm compression_type; if (m_compression_type == CompressionType::LZFSE) compression_type = COMPRESSION_LZFSE; else if (m_compression_type == CompressionType::ZlibDeflate) compression_type = COMPRESSION_ZLIB; else if (m_compression_type == CompressionType::LZ4) compression_type = COMPRESSION_LZ4_RAW; else if (m_compression_type == CompressionType::LZMA) compression_type = COMPRESSION_LZMA; if (m_decompression_scratch_type != m_compression_type) { if (m_decompression_scratch) { free (m_decompression_scratch); m_decompression_scratch = nullptr; } size_t scratchbuf_size = 0; if (m_compression_type == CompressionType::LZFSE) scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_LZFSE); else if (m_compression_type == CompressionType::LZ4) scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_LZ4_RAW); else if (m_compression_type == CompressionType::ZlibDeflate) scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_ZLIB); else if (m_compression_type == CompressionType::LZMA) scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_LZMA); else if (m_compression_type == CompressionType::LZFSE) scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_LZFSE); if (scratchbuf_size > 0) { m_decompression_scratch = (void*) malloc (scratchbuf_size); m_decompression_scratch_type = m_compression_type; } } if (decompressed_bufsize != ULONG_MAX && decompressed_buffer != nullptr) { decompressed_bytes = compression_decode_buffer( decompressed_buffer, decompressed_bufsize, (uint8_t *)unescaped_content.data(), unescaped_content.size(), m_decompression_scratch, compression_type); } } #endif #if LLVM_ENABLE_ZLIB if (decompressed_bytes == 0 && decompressed_bufsize != ULONG_MAX && decompressed_buffer != nullptr && m_compression_type == CompressionType::ZlibDeflate) { z_stream stream; memset(&stream, 0, sizeof(z_stream)); stream.next_in = (Bytef *)unescaped_content.data(); stream.avail_in = (uInt)unescaped_content.size(); stream.total_in = 0; stream.next_out = (Bytef *)decompressed_buffer; stream.avail_out = decompressed_bufsize; stream.total_out = 0; stream.zalloc = Z_NULL; stream.zfree = Z_NULL; stream.opaque = Z_NULL; if (inflateInit2(&stream, -15) == Z_OK) { int status = inflate(&stream, Z_NO_FLUSH); inflateEnd(&stream); if (status == Z_STREAM_END) { decompressed_bytes = stream.total_out; } } } #endif if (decompressed_bytes == 0 || decompressed_buffer == nullptr) { if (decompressed_buffer) free(decompressed_buffer); m_bytes.erase(0, size_of_first_packet); return false; } std::string new_packet; new_packet.reserve(decompressed_bytes + 6); new_packet.push_back(m_bytes[0]); new_packet.append((const char *)decompressed_buffer, decompressed_bytes); new_packet.push_back('#'); if (GetSendAcks()) { uint8_t decompressed_checksum = CalculcateChecksum( llvm::StringRef((const char *)decompressed_buffer, decompressed_bytes)); char decompressed_checksum_str[3]; snprintf(decompressed_checksum_str, 3, "%02x", decompressed_checksum); new_packet.append(decompressed_checksum_str); } else { new_packet.push_back('0'); new_packet.push_back('0'); } m_bytes.replace(0, size_of_first_packet, new_packet.data(), new_packet.size()); free(decompressed_buffer); return true; } GDBRemoteCommunication::PacketType GDBRemoteCommunication::CheckForPacket(const uint8_t *src, size_t src_len, StringExtractorGDBRemote &packet) { // Put the packet data into the buffer in a thread safe fashion std::lock_guard guard(m_bytes_mutex); Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_PACKETS)); if (src && src_len > 0) { if (log && log->GetVerbose()) { StreamString s; LLDB_LOGF(log, "GDBRemoteCommunication::%s adding %u bytes: %.*s", __FUNCTION__, (uint32_t)src_len, (uint32_t)src_len, src); } m_bytes.append((const char *)src, src_len); } bool isNotifyPacket = false; // Parse up the packets into gdb remote packets if (!m_bytes.empty()) { // end_idx must be one past the last valid packet byte. Start it off with // an invalid value that is the same as the current index. size_t content_start = 0; size_t content_length = 0; size_t total_length = 0; size_t checksum_idx = std::string::npos; // Size of packet before it is decompressed, for logging purposes size_t original_packet_size = m_bytes.size(); if (CompressionIsEnabled()) { if (!DecompressPacket()) { packet.Clear(); return GDBRemoteCommunication::PacketType::Standard; } } switch (m_bytes[0]) { case '+': // Look for ack case '-': // Look for cancel case '\x03': // ^C to halt target content_length = total_length = 1; // The command is one byte long... break; case '%': // Async notify packet isNotifyPacket = true; LLVM_FALLTHROUGH; case '$': // Look for a standard gdb packet? { size_t hash_pos = m_bytes.find('#'); if (hash_pos != std::string::npos) { if (hash_pos + 2 < m_bytes.size()) { checksum_idx = hash_pos + 1; // Skip the dollar sign content_start = 1; // Don't include the # in the content or the $ in the content // length content_length = hash_pos - 1; total_length = hash_pos + 3; // Skip the # and the two hex checksum bytes } else { // Checksum bytes aren't all here yet content_length = std::string::npos; } } } break; default: { // We have an unexpected byte and we need to flush all bad data that is // in m_bytes, so we need to find the first byte that is a '+' (ACK), '-' // (NACK), \x03 (CTRL+C interrupt), or '$' character (start of packet // header) or of course, the end of the data in m_bytes... const size_t bytes_len = m_bytes.size(); bool done = false; uint32_t idx; for (idx = 1; !done && idx < bytes_len; ++idx) { switch (m_bytes[idx]) { case '+': case '-': case '\x03': case '%': case '$': done = true; break; default: break; } } LLDB_LOGF(log, "GDBRemoteCommunication::%s tossing %u junk bytes: '%.*s'", __FUNCTION__, idx - 1, idx - 1, m_bytes.c_str()); m_bytes.erase(0, idx - 1); } break; } if (content_length == std::string::npos) { packet.Clear(); return GDBRemoteCommunication::PacketType::Invalid; } else if (total_length > 0) { // We have a valid packet... assert(content_length <= m_bytes.size()); assert(total_length <= m_bytes.size()); assert(content_length <= total_length); size_t content_end = content_start + content_length; bool success = true; if (log) { // If logging was just enabled and we have history, then dump out what // we have to the log so we get the historical context. The Dump() call // that logs all of the packet will set a boolean so that we don't dump // this more than once if (!m_history.DidDumpToLog()) m_history.Dump(log); bool binary = false; // Only detect binary for packets that start with a '$' and have a // '#CC' checksum if (m_bytes[0] == '$' && total_length > 4) { for (size_t i = 0; !binary && i < total_length; ++i) { unsigned char c = m_bytes[i]; if (!llvm::isPrint(c) && !llvm::isSpace(c)) { binary = true; } } } if (binary) { StreamString strm; // Packet header... if (CompressionIsEnabled()) strm.Printf("<%4" PRIu64 ":%" PRIu64 "> read packet: %c", (uint64_t)original_packet_size, (uint64_t)total_length, m_bytes[0]); else strm.Printf("<%4" PRIu64 "> read packet: %c", (uint64_t)total_length, m_bytes[0]); for (size_t i = content_start; i < content_end; ++i) { // Remove binary escaped bytes when displaying the packet... const char ch = m_bytes[i]; if (ch == 0x7d) { // 0x7d is the escape character. The next character is to be // XOR'd with 0x20. const char escapee = m_bytes[++i] ^ 0x20; strm.Printf("%2.2x", escapee); } else { strm.Printf("%2.2x", (uint8_t)ch); } } // Packet footer... strm.Printf("%c%c%c", m_bytes[total_length - 3], m_bytes[total_length - 2], m_bytes[total_length - 1]); log->PutString(strm.GetString()); } else { if (CompressionIsEnabled()) LLDB_LOGF(log, "<%4" PRIu64 ":%" PRIu64 "> read packet: %.*s", (uint64_t)original_packet_size, (uint64_t)total_length, (int)(total_length), m_bytes.c_str()); else LLDB_LOGF(log, "<%4" PRIu64 "> read packet: %.*s", (uint64_t)total_length, (int)(total_length), m_bytes.c_str()); } } m_history.AddPacket(m_bytes, total_length, GDBRemotePacket::ePacketTypeRecv, total_length); // Copy the packet from m_bytes to packet_str expanding the run-length // encoding in the process. std ::string packet_str = ExpandRLE(m_bytes.substr(content_start, content_end - content_start)); packet = StringExtractorGDBRemote(packet_str); if (m_bytes[0] == '$' || m_bytes[0] == '%') { assert(checksum_idx < m_bytes.size()); if (::isxdigit(m_bytes[checksum_idx + 0]) || ::isxdigit(m_bytes[checksum_idx + 1])) { if (GetSendAcks()) { const char *packet_checksum_cstr = &m_bytes[checksum_idx]; char packet_checksum = strtol(packet_checksum_cstr, nullptr, 16); char actual_checksum = CalculcateChecksum( llvm::StringRef(m_bytes).slice(content_start, content_end)); success = packet_checksum == actual_checksum; if (!success) { LLDB_LOGF(log, "error: checksum mismatch: %.*s expected 0x%2.2x, " "got 0x%2.2x", (int)(total_length), m_bytes.c_str(), (uint8_t)packet_checksum, (uint8_t)actual_checksum); } // Send the ack or nack if needed if (!success) SendNack(); else SendAck(); } } else { success = false; LLDB_LOGF(log, "error: invalid checksum in packet: '%s'\n", m_bytes.c_str()); } } m_bytes.erase(0, total_length); packet.SetFilePos(0); if (isNotifyPacket) return GDBRemoteCommunication::PacketType::Notify; else return GDBRemoteCommunication::PacketType::Standard; } } packet.Clear(); return GDBRemoteCommunication::PacketType::Invalid; } Status GDBRemoteCommunication::StartListenThread(const char *hostname, uint16_t port) { if (m_listen_thread.IsJoinable()) return Status("listen thread already running"); char listen_url[512]; if (hostname && hostname[0]) snprintf(listen_url, sizeof(listen_url), "listen://%s:%i", hostname, port); else snprintf(listen_url, sizeof(listen_url), "listen://%i", port); m_listen_url = listen_url; SetConnection(std::make_unique()); llvm::Expected listen_thread = ThreadLauncher::LaunchThread( listen_url, GDBRemoteCommunication::ListenThread, this); if (!listen_thread) return Status(listen_thread.takeError()); m_listen_thread = *listen_thread; return Status(); } bool GDBRemoteCommunication::JoinListenThread() { if (m_listen_thread.IsJoinable()) m_listen_thread.Join(nullptr); return true; } lldb::thread_result_t GDBRemoteCommunication::ListenThread(lldb::thread_arg_t arg) { GDBRemoteCommunication *comm = (GDBRemoteCommunication *)arg; Status error; ConnectionFileDescriptor *connection = (ConnectionFileDescriptor *)comm->GetConnection(); if (connection) { // Do the listen on another thread so we can continue on... if (connection->Connect(comm->m_listen_url.c_str(), &error) != eConnectionStatusSuccess) comm->SetConnection(nullptr); } return {}; } Status GDBRemoteCommunication::StartDebugserverProcess( const char *url, Platform *platform, ProcessLaunchInfo &launch_info, uint16_t *port, const Args *inferior_args, int pass_comm_fd) { Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_PROCESS)); LLDB_LOGF(log, "GDBRemoteCommunication::%s(url=%s, port=%" PRIu16 ")", __FUNCTION__, url ? url : "", port ? *port : uint16_t(0)); Status error; // If we locate debugserver, keep that located version around static FileSpec g_debugserver_file_spec; char debugserver_path[PATH_MAX]; FileSpec &debugserver_file_spec = launch_info.GetExecutableFile(); Environment host_env = Host::GetEnvironment(); // Always check to see if we have an environment override for the path to the // debugserver to use and use it if we do. std::string env_debugserver_path = host_env.lookup("LLDB_DEBUGSERVER_PATH"); if (!env_debugserver_path.empty()) { debugserver_file_spec.SetFile(env_debugserver_path, FileSpec::Style::native); LLDB_LOGF(log, "GDBRemoteCommunication::%s() gdb-remote stub exe path set " "from environment variable: %s", __FUNCTION__, env_debugserver_path.c_str()); } else debugserver_file_spec = g_debugserver_file_spec; bool debugserver_exists = FileSystem::Instance().Exists(debugserver_file_spec); if (!debugserver_exists) { // The debugserver binary is in the LLDB.framework/Resources directory. debugserver_file_spec = HostInfo::GetSupportExeDir(); if (debugserver_file_spec) { debugserver_file_spec.AppendPathComponent(DEBUGSERVER_BASENAME); debugserver_exists = FileSystem::Instance().Exists(debugserver_file_spec); if (debugserver_exists) { LLDB_LOGF(log, "GDBRemoteCommunication::%s() found gdb-remote stub exe '%s'", __FUNCTION__, debugserver_file_spec.GetPath().c_str()); g_debugserver_file_spec = debugserver_file_spec; } else { if (platform) debugserver_file_spec = platform->LocateExecutable(DEBUGSERVER_BASENAME); else debugserver_file_spec.Clear(); if (debugserver_file_spec) { // Platform::LocateExecutable() wouldn't return a path if it doesn't // exist debugserver_exists = true; } else { LLDB_LOGF(log, "GDBRemoteCommunication::%s() could not find " "gdb-remote stub exe '%s'", __FUNCTION__, debugserver_file_spec.GetPath().c_str()); } // Don't cache the platform specific GDB server binary as it could // change from platform to platform g_debugserver_file_spec.Clear(); } } } if (debugserver_exists) { debugserver_file_spec.GetPath(debugserver_path, sizeof(debugserver_path)); Args &debugserver_args = launch_info.GetArguments(); debugserver_args.Clear(); // Start args with "debugserver /file/path -r --" debugserver_args.AppendArgument(llvm::StringRef(debugserver_path)); #if !defined(__APPLE__) // First argument to lldb-server must be mode in which to run. debugserver_args.AppendArgument(llvm::StringRef("gdbserver")); #endif // If a url is supplied then use it if (url) debugserver_args.AppendArgument(llvm::StringRef(url)); if (pass_comm_fd >= 0) { StreamString fd_arg; fd_arg.Printf("--fd=%i", pass_comm_fd); debugserver_args.AppendArgument(fd_arg.GetString()); // Send "pass_comm_fd" down to the inferior so it can use it to // communicate back with this process launch_info.AppendDuplicateFileAction(pass_comm_fd, pass_comm_fd); } // use native registers, not the GDB registers debugserver_args.AppendArgument(llvm::StringRef("--native-regs")); if (launch_info.GetLaunchInSeparateProcessGroup()) { debugserver_args.AppendArgument(llvm::StringRef("--setsid")); } llvm::SmallString<128> named_pipe_path; // socket_pipe is used by debug server to communicate back either // TCP port or domain socket name which it listens on. // The second purpose of the pipe to serve as a synchronization point - // once data is written to the pipe, debug server is up and running. Pipe socket_pipe; // port is null when debug server should listen on domain socket - we're // not interested in port value but rather waiting for debug server to // become available. if (pass_comm_fd == -1) { if (url) { // Create a temporary file to get the stdout/stderr and redirect the output of // the command into this file. We will later read this file if all goes well // and fill the data into "command_output_ptr" #if defined(__APPLE__) // Binding to port zero, we need to figure out what port it ends up // using using a named pipe... error = socket_pipe.CreateWithUniqueName("debugserver-named-pipe", false, named_pipe_path); if (error.Fail()) { LLDB_LOGF(log, "GDBRemoteCommunication::%s() " "named pipe creation failed: %s", __FUNCTION__, error.AsCString()); return error; } debugserver_args.AppendArgument(llvm::StringRef("--named-pipe")); debugserver_args.AppendArgument(named_pipe_path); #else // Binding to port zero, we need to figure out what port it ends up // using using an unnamed pipe... error = socket_pipe.CreateNew(true); if (error.Fail()) { LLDB_LOGF(log, "GDBRemoteCommunication::%s() " "unnamed pipe creation failed: %s", __FUNCTION__, error.AsCString()); return error; } pipe_t write = socket_pipe.GetWritePipe(); debugserver_args.AppendArgument(llvm::StringRef("--pipe")); debugserver_args.AppendArgument(llvm::to_string(write)); launch_info.AppendCloseFileAction(socket_pipe.GetReadFileDescriptor()); #endif } else { // No host and port given, so lets listen on our end and make the // debugserver connect to us.. error = StartListenThread("127.0.0.1", 0); if (error.Fail()) { LLDB_LOGF(log, "GDBRemoteCommunication::%s() unable to start listen " "thread: %s", __FUNCTION__, error.AsCString()); return error; } ConnectionFileDescriptor *connection = (ConnectionFileDescriptor *)GetConnection(); // Wait for 10 seconds to resolve the bound port uint16_t port_ = connection->GetListeningPort(std::chrono::seconds(10)); if (port_ > 0) { char port_cstr[32]; snprintf(port_cstr, sizeof(port_cstr), "127.0.0.1:%i", port_); // Send the host and port down that debugserver and specify an option // so that it connects back to the port we are listening to in this // process debugserver_args.AppendArgument(llvm::StringRef("--reverse-connect")); debugserver_args.AppendArgument(llvm::StringRef(port_cstr)); if (port) *port = port_; } else { error.SetErrorString("failed to bind to port 0 on 127.0.0.1"); LLDB_LOGF(log, "GDBRemoteCommunication::%s() failed: %s", __FUNCTION__, error.AsCString()); return error; } } } std::string env_debugserver_log_file = host_env.lookup("LLDB_DEBUGSERVER_LOG_FILE"); if (!env_debugserver_log_file.empty()) { debugserver_args.AppendArgument( llvm::formatv("--log-file={0}", env_debugserver_log_file).str()); } #if defined(__APPLE__) const char *env_debugserver_log_flags = getenv("LLDB_DEBUGSERVER_LOG_FLAGS"); if (env_debugserver_log_flags) { debugserver_args.AppendArgument( llvm::formatv("--log-flags={0}", env_debugserver_log_flags).str()); } #else std::string env_debugserver_log_channels = host_env.lookup("LLDB_SERVER_LOG_CHANNELS"); if (!env_debugserver_log_channels.empty()) { debugserver_args.AppendArgument( llvm::formatv("--log-channels={0}", env_debugserver_log_channels) .str()); } #endif // Add additional args, starting with LLDB_DEBUGSERVER_EXTRA_ARG_1 until an // env var doesn't come back. uint32_t env_var_index = 1; bool has_env_var; do { char env_var_name[64]; snprintf(env_var_name, sizeof(env_var_name), "LLDB_DEBUGSERVER_EXTRA_ARG_%" PRIu32, env_var_index++); std::string extra_arg = host_env.lookup(env_var_name); has_env_var = !extra_arg.empty(); if (has_env_var) { debugserver_args.AppendArgument(llvm::StringRef(extra_arg)); LLDB_LOGF(log, "GDBRemoteCommunication::%s adding env var %s contents " "to stub command line (%s)", __FUNCTION__, env_var_name, extra_arg.c_str()); } } while (has_env_var); if (inferior_args && inferior_args->GetArgumentCount() > 0) { debugserver_args.AppendArgument(llvm::StringRef("--")); debugserver_args.AppendArguments(*inferior_args); } // Copy the current environment to the gdbserver/debugserver instance launch_info.GetEnvironment() = host_env; // Close STDIN, STDOUT and STDERR. launch_info.AppendCloseFileAction(STDIN_FILENO); launch_info.AppendCloseFileAction(STDOUT_FILENO); launch_info.AppendCloseFileAction(STDERR_FILENO); // Redirect STDIN, STDOUT and STDERR to "/dev/null". launch_info.AppendSuppressFileAction(STDIN_FILENO, true, false); launch_info.AppendSuppressFileAction(STDOUT_FILENO, false, true); launch_info.AppendSuppressFileAction(STDERR_FILENO, false, true); if (log) { StreamString string_stream; Platform *const platform = nullptr; launch_info.Dump(string_stream, platform); LLDB_LOGF(log, "launch info for gdb-remote stub:\n%s", string_stream.GetData()); } error = Host::LaunchProcess(launch_info); if (error.Success() && (launch_info.GetProcessID() != LLDB_INVALID_PROCESS_ID) && pass_comm_fd == -1) { if (named_pipe_path.size() > 0) { error = socket_pipe.OpenAsReader(named_pipe_path, false); if (error.Fail()) LLDB_LOGF(log, "GDBRemoteCommunication::%s() " "failed to open named pipe %s for reading: %s", __FUNCTION__, named_pipe_path.c_str(), error.AsCString()); } if (socket_pipe.CanWrite()) socket_pipe.CloseWriteFileDescriptor(); if (socket_pipe.CanRead()) { char port_cstr[PATH_MAX] = {0}; port_cstr[0] = '\0'; size_t num_bytes = sizeof(port_cstr); // Read port from pipe with 10 second timeout. error = socket_pipe.ReadWithTimeout( port_cstr, num_bytes, std::chrono::seconds{10}, num_bytes); if (error.Success() && (port != nullptr)) { assert(num_bytes > 0 && port_cstr[num_bytes - 1] == '\0'); uint16_t child_port = StringConvert::ToUInt32(port_cstr, 0); if (*port == 0 || *port == child_port) { *port = child_port; LLDB_LOGF(log, "GDBRemoteCommunication::%s() " "debugserver listens %u port", __FUNCTION__, *port); } else { LLDB_LOGF(log, "GDBRemoteCommunication::%s() " "debugserver listening on port " "%d but requested port was %d", __FUNCTION__, (uint32_t)child_port, (uint32_t)(*port)); } } else { LLDB_LOGF(log, "GDBRemoteCommunication::%s() " "failed to read a port value from pipe %s: %s", __FUNCTION__, named_pipe_path.c_str(), error.AsCString()); } socket_pipe.Close(); } if (named_pipe_path.size() > 0) { const auto err = socket_pipe.Delete(named_pipe_path); if (err.Fail()) { LLDB_LOGF(log, "GDBRemoteCommunication::%s failed to delete pipe %s: %s", __FUNCTION__, named_pipe_path.c_str(), err.AsCString()); } } // Make sure we actually connect with the debugserver... JoinListenThread(); } } else { error.SetErrorStringWithFormat("unable to locate " DEBUGSERVER_BASENAME); } if (error.Fail()) { LLDB_LOGF(log, "GDBRemoteCommunication::%s() failed: %s", __FUNCTION__, error.AsCString()); } return error; } void GDBRemoteCommunication::DumpHistory(Stream &strm) { m_history.Dump(strm); } void GDBRemoteCommunication::SetPacketRecorder( repro::PacketRecorder *recorder) { m_history.SetRecorder(recorder); } llvm::Error GDBRemoteCommunication::ConnectLocally(GDBRemoteCommunication &client, GDBRemoteCommunication &server) { const bool child_processes_inherit = false; const int backlog = 5; TCPSocket listen_socket(true, child_processes_inherit); if (llvm::Error error = listen_socket.Listen("localhost:0", backlog).ToError()) return error; Socket *accept_socket; std::future accept_status = std::async( std::launch::async, [&] { return listen_socket.Accept(accept_socket); }); llvm::SmallString<32> remote_addr; llvm::raw_svector_ostream(remote_addr) << "connect://localhost:" << listen_socket.GetLocalPortNumber(); std::unique_ptr conn_up( new ConnectionFileDescriptor()); Status status; if (conn_up->Connect(remote_addr, &status) != lldb::eConnectionStatusSuccess) return llvm::createStringError(llvm::inconvertibleErrorCode(), "Unable to connect: %s", status.AsCString()); client.SetConnection(std::move(conn_up)); if (llvm::Error error = accept_status.get().ToError()) return error; server.SetConnection( std::make_unique(accept_socket)); return llvm::Error::success(); } GDBRemoteCommunication::ScopedTimeout::ScopedTimeout( GDBRemoteCommunication &gdb_comm, std::chrono::seconds timeout) : m_gdb_comm(gdb_comm), m_timeout_modified(false) { auto curr_timeout = gdb_comm.GetPacketTimeout(); // Only update the timeout if the timeout is greater than the current // timeout. If the current timeout is larger, then just use that. if (curr_timeout < timeout) { m_timeout_modified = true; m_saved_timeout = m_gdb_comm.SetPacketTimeout(timeout); } } GDBRemoteCommunication::ScopedTimeout::~ScopedTimeout() { // Only restore the timeout if we set it in the constructor. if (m_timeout_modified) m_gdb_comm.SetPacketTimeout(m_saved_timeout); } // This function is called via the Communications class read thread when bytes // become available for this connection. This function will consume all // incoming bytes and try to parse whole packets as they become available. Full // packets are placed in a queue, so that all packet requests can simply pop // from this queue. Async notification packets will be dispatched immediately // to the ProcessGDBRemote Async thread via an event. void GDBRemoteCommunication::AppendBytesToCache(const uint8_t *bytes, size_t len, bool broadcast, lldb::ConnectionStatus status) { StringExtractorGDBRemote packet; while (true) { PacketType type = CheckForPacket(bytes, len, packet); // scrub the data so we do not pass it back to CheckForPacket on future // passes of the loop bytes = nullptr; len = 0; // we may have received no packet so lets bail out if (type == PacketType::Invalid) break; if (type == PacketType::Standard) { // scope for the mutex { // lock down the packet queue std::lock_guard guard(m_packet_queue_mutex); // push a new packet into the queue m_packet_queue.push(packet); // Signal condition variable that we have a packet m_condition_queue_not_empty.notify_one(); } } if (type == PacketType::Notify) { // put this packet into an event const char *pdata = packet.GetStringRef().data(); // as the communication class, we are a broadcaster and the async thread // is tuned to listen to us BroadcastEvent(eBroadcastBitGdbReadThreadGotNotify, new EventDataBytes(pdata)); } } } void llvm::format_provider::format( const GDBRemoteCommunication::PacketResult &result, raw_ostream &Stream, StringRef Style) { using PacketResult = GDBRemoteCommunication::PacketResult; switch (result) { case PacketResult::Success: Stream << "Success"; break; case PacketResult::ErrorSendFailed: Stream << "ErrorSendFailed"; break; case PacketResult::ErrorSendAck: Stream << "ErrorSendAck"; break; case PacketResult::ErrorReplyFailed: Stream << "ErrorReplyFailed"; break; case PacketResult::ErrorReplyTimeout: Stream << "ErrorReplyTimeout"; break; case PacketResult::ErrorReplyInvalid: Stream << "ErrorReplyInvalid"; break; case PacketResult::ErrorReplyAck: Stream << "ErrorReplyAck"; break; case PacketResult::ErrorDisconnected: Stream << "ErrorDisconnected"; break; case PacketResult::ErrorNoSequenceLock: Stream << "ErrorNoSequenceLock"; break; } } std::string GDBRemoteCommunication::ExpandRLE(std::string packet) { // Reserve enough byte for the most common case (no RLE used). std::string decoded; decoded.reserve(packet.size()); for (std::string::const_iterator c = packet.begin(); c != packet.end(); ++c) { if (*c == '*') { // '*' indicates RLE. Next character will give us the repeat count and // previous character is what is to be repeated. char char_to_repeat = decoded.back(); // Number of time the previous character is repeated. int repeat_count = *++c + 3 - ' '; // We have the char_to_repeat and repeat_count. Now push it in the // packet. for (int i = 0; i < repeat_count; ++i) decoded.push_back(char_to_repeat); } else if (*c == 0x7d) { // 0x7d is the escape character. The next character is to be XOR'd with // 0x20. char escapee = *++c ^ 0x20; decoded.push_back(escapee); } else { decoded.push_back(*c); } } return decoded; }