1097 lines · cpp
1//===-- GDBRemoteCommunication.cpp ----------------------------------------===//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-exception6//7//===----------------------------------------------------------------------===//8 9#include "GDBRemoteCommunication.h"10#include "ProcessGDBRemoteLog.h"11#include "lldb/Host/Config.h"12#include "lldb/Host/FileSystem.h"13#include "lldb/Host/Host.h"14#include "lldb/Host/Pipe.h"15#include "lldb/Host/ProcessLaunchInfo.h"16#include "lldb/Host/Socket.h"17#include "lldb/Host/common/TCPSocket.h"18#include "lldb/Host/posix/ConnectionFileDescriptorPosix.h"19#include "lldb/Target/Platform.h"20#include "lldb/Utility/Event.h"21#include "lldb/Utility/FileSpec.h"22#include "lldb/Utility/Log.h"23#include "lldb/Utility/RegularExpression.h"24#include "lldb/Utility/StreamString.h"25#include "llvm/ADT/SmallString.h"26#include "llvm/ADT/StringRef.h"27#include "llvm/Config/llvm-config.h" // for LLVM_ENABLE_ZLIB28#include "llvm/Support/Error.h"29#include "llvm/Support/ScopedPrinter.h"30#include <climits>31#include <cstring>32#include <sys/stat.h>33#include <variant>34 35#if HAVE_LIBCOMPRESSION36#include <compression.h>37#endif38 39#if LLVM_ENABLE_ZLIB40#include <zlib.h>41#endif42 43using namespace lldb;44using namespace lldb_private;45using namespace lldb_private::process_gdb_remote;46 47// GDBRemoteCommunication constructor48GDBRemoteCommunication::GDBRemoteCommunication()49 : Communication(),50#ifdef LLDB_CONFIGURATION_DEBUG51 m_packet_timeout(1000),52#else53 m_packet_timeout(1),54#endif55 m_echo_number(0), m_supports_qEcho(eLazyBoolCalculate), m_history(512),56 m_send_acks(true), m_is_platform(false),57 m_compression_type(CompressionType::None) {58}59 60// Destructor61GDBRemoteCommunication::~GDBRemoteCommunication() {62 if (IsConnected()) {63 Disconnect();64 }65 66#if HAVE_LIBCOMPRESSION67 if (m_decompression_scratch)68 free (m_decompression_scratch);69#endif70}71 72char GDBRemoteCommunication::CalculcateChecksum(llvm::StringRef payload) {73 int checksum = 0;74 75 for (char c : payload)76 checksum += c;77 78 return checksum & 255;79}80 81size_t GDBRemoteCommunication::SendAck() {82 Log *log = GetLog(GDBRLog::Packets);83 ConnectionStatus status = eConnectionStatusSuccess;84 char ch = '+';85 const size_t bytes_written = WriteAll(&ch, 1, status, nullptr);86 LLDB_LOGF(log, "<%4" PRIu64 "> send packet: %c", (uint64_t)bytes_written, ch);87 m_history.AddPacket(ch, GDBRemotePacket::ePacketTypeSend, bytes_written);88 return bytes_written;89}90 91size_t GDBRemoteCommunication::SendNack() {92 Log *log = GetLog(GDBRLog::Packets);93 ConnectionStatus status = eConnectionStatusSuccess;94 char ch = '-';95 const size_t bytes_written = WriteAll(&ch, 1, status, nullptr);96 LLDB_LOGF(log, "<%4" PRIu64 "> send packet: %c", (uint64_t)bytes_written, ch);97 m_history.AddPacket(ch, GDBRemotePacket::ePacketTypeSend, bytes_written);98 return bytes_written;99}100 101GDBRemoteCommunication::PacketResult102GDBRemoteCommunication::SendPacketNoLock(llvm::StringRef payload) {103 StreamString packet(0, 4, eByteOrderBig);104 packet.PutChar('$');105 packet.Write(payload.data(), payload.size());106 packet.PutChar('#');107 packet.PutHex8(CalculcateChecksum(payload));108 std::string packet_str = std::string(packet.GetString());109 110 return SendRawPacketNoLock(packet_str);111}112 113GDBRemoteCommunication::PacketResult114GDBRemoteCommunication::SendNotificationPacketNoLock(115 llvm::StringRef notify_type, std::deque<std::string> &queue,116 llvm::StringRef payload) {117 PacketResult ret = PacketResult::Success;118 119 // If there are no notification in the queue, send the notification120 // packet.121 if (queue.empty()) {122 StreamString packet(0, 4, eByteOrderBig);123 packet.PutChar('%');124 packet.Write(notify_type.data(), notify_type.size());125 packet.PutChar(':');126 packet.Write(payload.data(), payload.size());127 packet.PutChar('#');128 packet.PutHex8(CalculcateChecksum(payload));129 ret = SendRawPacketNoLock(packet.GetString(), true);130 }131 132 queue.push_back(payload.str());133 return ret;134}135 136GDBRemoteCommunication::PacketResult137GDBRemoteCommunication::SendRawPacketNoLock(llvm::StringRef packet,138 bool skip_ack) {139 if (IsConnected()) {140 Log *log = GetLog(GDBRLog::Packets);141 ConnectionStatus status = eConnectionStatusSuccess;142 const char *packet_data = packet.data();143 const size_t packet_length = packet.size();144 size_t bytes_written = WriteAll(packet_data, packet_length, status, nullptr);145 if (log) {146 size_t binary_start_offset = 0;147 if (strncmp(packet_data, "$vFile:pwrite:", strlen("$vFile:pwrite:")) ==148 0) {149 const char *first_comma = strchr(packet_data, ',');150 if (first_comma) {151 const char *second_comma = strchr(first_comma + 1, ',');152 if (second_comma)153 binary_start_offset = second_comma - packet_data + 1;154 }155 }156 157 // If logging was just enabled and we have history, then dump out what we158 // have to the log so we get the historical context. The Dump() call that159 // logs all of the packet will set a boolean so that we don't dump this160 // more than once161 if (!m_history.DidDumpToLog())162 m_history.Dump(log);163 164 if (binary_start_offset) {165 StreamString strm;166 // Print non binary data header167 strm.Printf("<%4" PRIu64 "> send packet: %.*s", (uint64_t)bytes_written,168 (int)binary_start_offset, packet_data);169 const uint8_t *p;170 // Print binary data exactly as sent171 for (p = (const uint8_t *)packet_data + binary_start_offset; *p != '#';172 ++p)173 strm.Printf("\\x%2.2x", *p);174 // Print the checksum175 strm.Printf("%*s", (int)3, p);176 log->PutString(strm.GetString());177 } else178 LLDB_LOGF(log, "<%4" PRIu64 "> send packet: %.*s",179 (uint64_t)bytes_written, (int)packet_length, packet_data);180 }181 182 m_history.AddPacket(packet.str(), packet_length,183 GDBRemotePacket::ePacketTypeSend, bytes_written);184 185 if (bytes_written == packet_length) {186 if (!skip_ack && GetSendAcks())187 return GetAck();188 else189 return PacketResult::Success;190 } else {191 LLDB_LOGF(log, "error: failed to send packet: %.*s", (int)packet_length,192 packet_data);193 }194 }195 return PacketResult::ErrorSendFailed;196}197 198GDBRemoteCommunication::PacketResult GDBRemoteCommunication::GetAck() {199 StringExtractorGDBRemote packet;200 PacketResult result = WaitForPacketNoLock(packet, GetPacketTimeout(), false);201 if (result == PacketResult::Success) {202 if (packet.GetResponseType() ==203 StringExtractorGDBRemote::ResponseType::eAck)204 return PacketResult::Success;205 else206 return PacketResult::ErrorSendAck;207 }208 return result;209}210 211GDBRemoteCommunication::PacketResult212GDBRemoteCommunication::ReadPacket(StringExtractorGDBRemote &response,213 Timeout<std::micro> timeout,214 bool sync_on_timeout) {215 using ResponseType = StringExtractorGDBRemote::ResponseType;216 217 Log *log = GetLog(GDBRLog::Packets);218 for (;;) {219 PacketResult result =220 WaitForPacketNoLock(response, timeout, sync_on_timeout);221 if (result != PacketResult::Success ||222 (response.GetResponseType() != ResponseType::eAck &&223 response.GetResponseType() != ResponseType::eNack))224 return result;225 LLDB_LOG(log, "discarding spurious `{0}` packet", response.GetStringRef());226 }227}228 229GDBRemoteCommunication::PacketResult230GDBRemoteCommunication::WaitForPacketNoLock(StringExtractorGDBRemote &packet,231 Timeout<std::micro> timeout,232 bool sync_on_timeout) {233 uint8_t buffer[8192];234 Status error;235 236 Log *log = GetLog(GDBRLog::Packets);237 238 // Check for a packet from our cache first without trying any reading...239 if (CheckForPacket(nullptr, 0, packet) != PacketType::Invalid)240 return PacketResult::Success;241 242 bool timed_out = false;243 bool disconnected = false;244 while (IsConnected() && !timed_out) {245 lldb::ConnectionStatus status = eConnectionStatusNoConnection;246 size_t bytes_read = Read(buffer, sizeof(buffer), timeout, status, &error);247 248 LLDB_LOGV(log,249 "Read(buffer, sizeof(buffer), timeout = {0}, "250 "status = {1}, error = {2}) => bytes_read = {3}",251 timeout, Communication::ConnectionStatusAsString(status), error,252 bytes_read);253 254 if (bytes_read > 0) {255 if (CheckForPacket(buffer, bytes_read, packet) != PacketType::Invalid)256 return PacketResult::Success;257 } else {258 switch (status) {259 case eConnectionStatusTimedOut:260 case eConnectionStatusInterrupted:261 if (sync_on_timeout) {262 /// Sync the remote GDB server and make sure we get a response that263 /// corresponds to what we send.264 ///265 /// Sends a "qEcho" packet and makes sure it gets the exact packet266 /// echoed back. If the qEcho packet isn't supported, we send a qC267 /// packet and make sure we get a valid thread ID back. We use the268 /// "qC" packet since its response if very unique: is responds with269 /// "QC%x" where %x is the thread ID of the current thread. This270 /// makes the response unique enough from other packet responses to271 /// ensure we are back on track.272 ///273 /// This packet is needed after we time out sending a packet so we274 /// can ensure that we are getting the response for the packet we275 /// are sending. There are no sequence IDs in the GDB remote276 /// protocol (there used to be, but they are not supported anymore)277 /// so if you timeout sending packet "abc", you might then send278 /// packet "cde" and get the response for the previous "abc" packet.279 /// Many responses are "OK" or "" (unsupported) or "EXX" (error) so280 /// many responses for packets can look like responses for other281 /// packets. So if we timeout, we need to ensure that we can get282 /// back on track. If we can't get back on track, we must283 /// disconnect.284 bool sync_success = false;285 bool got_actual_response = false;286 // We timed out, we need to sync back up with the287 char echo_packet[32];288 int echo_packet_len = 0;289 RegularExpression response_regex;290 291 if (m_supports_qEcho == eLazyBoolYes) {292 echo_packet_len = ::snprintf(echo_packet, sizeof(echo_packet),293 "qEcho:%u", ++m_echo_number);294 std::string regex_str = "^";295 regex_str += echo_packet;296 regex_str += "$";297 response_regex = RegularExpression(regex_str);298 } else {299 echo_packet_len =300 ::snprintf(echo_packet, sizeof(echo_packet), "qC");301 response_regex =302 RegularExpression(llvm::StringRef("^QC[0-9A-Fa-f]+$"));303 }304 305 PacketResult echo_packet_result =306 SendPacketNoLock(llvm::StringRef(echo_packet, echo_packet_len));307 if (echo_packet_result == PacketResult::Success) {308 const uint32_t max_retries = 3;309 uint32_t successful_responses = 0;310 for (uint32_t i = 0; i < max_retries; ++i) {311 StringExtractorGDBRemote echo_response;312 echo_packet_result =313 WaitForPacketNoLock(echo_response, timeout, false);314 if (echo_packet_result == PacketResult::Success) {315 ++successful_responses;316 if (response_regex.Execute(echo_response.GetStringRef())) {317 sync_success = true;318 break;319 } else if (successful_responses == 1) {320 // We got something else back as the first successful321 // response, it probably is the response to the packet we322 // actually wanted, so copy it over if this is the first323 // success and continue to try to get the qEcho response324 packet = echo_response;325 got_actual_response = true;326 }327 } else if (echo_packet_result == PacketResult::ErrorReplyTimeout)328 continue; // Packet timed out, continue waiting for a response329 else330 break; // Something else went wrong getting the packet back, we331 // failed and are done trying332 }333 }334 335 // We weren't able to sync back up with the server, we must abort336 // otherwise all responses might not be from the right packets...337 if (sync_success) {338 // We timed out, but were able to recover339 if (got_actual_response) {340 // We initially timed out, but we did get a response that came in341 // before the successful reply to our qEcho packet, so lets say342 // everything is fine...343 return PacketResult::Success;344 }345 } else {346 disconnected = true;347 Disconnect();348 }349 } else {350 timed_out = true;351 }352 break;353 case eConnectionStatusSuccess:354 // printf ("status = success but error = %s\n",355 // error.AsCString("<invalid>"));356 break;357 358 case eConnectionStatusEndOfFile:359 case eConnectionStatusNoConnection:360 case eConnectionStatusLostConnection:361 case eConnectionStatusError:362 disconnected = true;363 Disconnect();364 break;365 }366 }367 }368 packet.Clear();369 if (disconnected)370 return PacketResult::ErrorDisconnected;371 if (timed_out)372 return PacketResult::ErrorReplyTimeout;373 else374 return PacketResult::ErrorReplyFailed;375}376 377bool GDBRemoteCommunication::DecompressPacket() {378 Log *log = GetLog(GDBRLog::Packets);379 380 if (!CompressionIsEnabled())381 return true;382 383 size_t pkt_size = m_bytes.size();384 385 // Smallest possible compressed packet is $N#00 - an uncompressed empty386 // reply, most commonly indicating an unsupported packet. Anything less than387 // 5 characters, it's definitely not a compressed packet.388 if (pkt_size < 5)389 return true;390 391 if (m_bytes[0] != '$' && m_bytes[0] != '%')392 return true;393 if (m_bytes[1] != 'C' && m_bytes[1] != 'N')394 return true;395 396 size_t hash_mark_idx = m_bytes.find('#');397 if (hash_mark_idx == std::string::npos)398 return true;399 if (hash_mark_idx + 2 >= m_bytes.size())400 return true;401 402 if (!::isxdigit(m_bytes[hash_mark_idx + 1]) ||403 !::isxdigit(m_bytes[hash_mark_idx + 2]))404 return true;405 406 size_t content_length =407 pkt_size -408 5; // not counting '$', 'C' | 'N', '#', & the two hex checksum chars409 size_t content_start = 2; // The first character of the410 // compressed/not-compressed text of the packet411 size_t checksum_idx =412 hash_mark_idx +413 1; // The first character of the two hex checksum characters414 415 // Normally size_of_first_packet == m_bytes.size() but m_bytes may contain416 // multiple packets. size_of_first_packet is the size of the initial packet417 // which we'll replace with the decompressed version of, leaving the rest of418 // m_bytes unmodified.419 size_t size_of_first_packet = hash_mark_idx + 3;420 421 // Compressed packets ("$C") start with a base10 number which is the size of422 // the uncompressed payload, then a : and then the compressed data. e.g.423 // $C1024:<binary>#00 Update content_start and content_length to only include424 // the <binary> part of the packet.425 426 uint64_t decompressed_bufsize = ULONG_MAX;427 if (m_bytes[1] == 'C') {428 size_t i = content_start;429 while (i < hash_mark_idx && isdigit(m_bytes[i]))430 i++;431 if (i < hash_mark_idx && m_bytes[i] == ':') {432 i++;433 content_start = i;434 content_length = hash_mark_idx - content_start;435 std::string bufsize_str(m_bytes.data() + 2, i - 2 - 1);436 errno = 0;437 decompressed_bufsize = ::strtoul(bufsize_str.c_str(), nullptr, 10);438 if (errno != 0 || decompressed_bufsize == ULONG_MAX) {439 m_bytes.erase(0, size_of_first_packet);440 return false;441 }442 }443 }444 445 if (GetSendAcks()) {446 char packet_checksum_cstr[3];447 packet_checksum_cstr[0] = m_bytes[checksum_idx];448 packet_checksum_cstr[1] = m_bytes[checksum_idx + 1];449 packet_checksum_cstr[2] = '\0';450 long packet_checksum = strtol(packet_checksum_cstr, nullptr, 16);451 452 long actual_checksum = CalculcateChecksum(453 llvm::StringRef(m_bytes).substr(1, hash_mark_idx - 1));454 bool success = packet_checksum == actual_checksum;455 if (!success) {456 LLDB_LOGF(log,457 "error: checksum mismatch: %.*s expected 0x%2.2x, got 0x%2.2x",458 (int)(pkt_size), m_bytes.c_str(), (uint8_t)packet_checksum,459 (uint8_t)actual_checksum);460 }461 // Send the ack or nack if needed462 if (!success) {463 SendNack();464 m_bytes.erase(0, size_of_first_packet);465 return false;466 } else {467 SendAck();468 }469 }470 471 if (m_bytes[1] == 'N') {472 // This packet was not compressed -- delete the 'N' character at the start473 // and the packet may be processed as-is.474 m_bytes.erase(1, 1);475 return true;476 }477 478 // Reverse the gdb-remote binary escaping that was done to the compressed479 // text to guard characters like '$', '#', '}', etc.480 std::vector<uint8_t> unescaped_content;481 unescaped_content.reserve(content_length);482 size_t i = content_start;483 while (i < hash_mark_idx) {484 if (m_bytes[i] == '}') {485 i++;486 unescaped_content.push_back(m_bytes[i] ^ 0x20);487 } else {488 unescaped_content.push_back(m_bytes[i]);489 }490 i++;491 }492 493 uint8_t *decompressed_buffer = nullptr;494 size_t decompressed_bytes = 0;495 496 if (decompressed_bufsize != ULONG_MAX) {497 decompressed_buffer = (uint8_t *)malloc(decompressed_bufsize);498 if (decompressed_buffer == nullptr) {499 m_bytes.erase(0, size_of_first_packet);500 return false;501 }502 }503 504#if HAVE_LIBCOMPRESSION505 if (m_compression_type == CompressionType::ZlibDeflate ||506 m_compression_type == CompressionType::LZFSE ||507 m_compression_type == CompressionType::LZ4 ||508 m_compression_type == CompressionType::LZMA) {509 compression_algorithm compression_type;510 if (m_compression_type == CompressionType::LZFSE)511 compression_type = COMPRESSION_LZFSE;512 else if (m_compression_type == CompressionType::ZlibDeflate)513 compression_type = COMPRESSION_ZLIB;514 else if (m_compression_type == CompressionType::LZ4)515 compression_type = COMPRESSION_LZ4_RAW;516 else if (m_compression_type == CompressionType::LZMA)517 compression_type = COMPRESSION_LZMA;518 519 if (m_decompression_scratch_type != m_compression_type) {520 if (m_decompression_scratch) {521 free (m_decompression_scratch);522 m_decompression_scratch = nullptr;523 }524 size_t scratchbuf_size = 0;525 if (m_compression_type == CompressionType::LZFSE)526 scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_LZFSE);527 else if (m_compression_type == CompressionType::LZ4)528 scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_LZ4_RAW);529 else if (m_compression_type == CompressionType::ZlibDeflate)530 scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_ZLIB);531 else if (m_compression_type == CompressionType::LZMA)532 scratchbuf_size =533 compression_decode_scratch_buffer_size(COMPRESSION_LZMA);534 if (scratchbuf_size > 0) {535 m_decompression_scratch = (void*) malloc (scratchbuf_size);536 m_decompression_scratch_type = m_compression_type;537 }538 }539 540 if (decompressed_bufsize != ULONG_MAX && decompressed_buffer != nullptr) {541 decompressed_bytes = compression_decode_buffer(542 decompressed_buffer, decompressed_bufsize,543 (uint8_t *)unescaped_content.data(), unescaped_content.size(),544 m_decompression_scratch, compression_type);545 }546 }547#endif548 549#if LLVM_ENABLE_ZLIB550 if (decompressed_bytes == 0 && decompressed_bufsize != ULONG_MAX &&551 decompressed_buffer != nullptr &&552 m_compression_type == CompressionType::ZlibDeflate) {553 z_stream stream;554 memset(&stream, 0, sizeof(z_stream));555 stream.next_in = (Bytef *)unescaped_content.data();556 stream.avail_in = (uInt)unescaped_content.size();557 stream.total_in = 0;558 stream.next_out = (Bytef *)decompressed_buffer;559 stream.avail_out = decompressed_bufsize;560 stream.total_out = 0;561 stream.zalloc = Z_NULL;562 stream.zfree = Z_NULL;563 stream.opaque = Z_NULL;564 565 if (inflateInit2(&stream, -15) == Z_OK) {566 int status = inflate(&stream, Z_NO_FLUSH);567 inflateEnd(&stream);568 if (status == Z_STREAM_END) {569 decompressed_bytes = stream.total_out;570 }571 }572 }573#endif574 575 if (decompressed_bytes == 0 || decompressed_buffer == nullptr) {576 if (decompressed_buffer)577 free(decompressed_buffer);578 m_bytes.erase(0, size_of_first_packet);579 return false;580 }581 582 std::string new_packet;583 new_packet.reserve(decompressed_bytes + 6);584 new_packet.push_back(m_bytes[0]);585 new_packet.append((const char *)decompressed_buffer, decompressed_bytes);586 new_packet.push_back('#');587 if (GetSendAcks()) {588 uint8_t decompressed_checksum = CalculcateChecksum(589 llvm::StringRef((const char *)decompressed_buffer, decompressed_bytes));590 char decompressed_checksum_str[3];591 snprintf(decompressed_checksum_str, 3, "%02x", decompressed_checksum);592 new_packet.append(decompressed_checksum_str);593 } else {594 new_packet.push_back('0');595 new_packet.push_back('0');596 }597 598 m_bytes.replace(0, size_of_first_packet, new_packet.data(),599 new_packet.size());600 601 free(decompressed_buffer);602 return true;603}604 605GDBRemoteCommunication::PacketType606GDBRemoteCommunication::CheckForPacket(const uint8_t *src, size_t src_len,607 StringExtractorGDBRemote &packet) {608 // Put the packet data into the buffer in a thread safe fashion609 std::lock_guard<std::recursive_mutex> guard(m_bytes_mutex);610 611 Log *log = GetLog(GDBRLog::Packets);612 613 if (src && src_len > 0) {614 if (log && log->GetVerbose()) {615 StreamString s;616 LLDB_LOGF(log, "GDBRemoteCommunication::%s adding %u bytes: %.*s",617 __FUNCTION__, (uint32_t)src_len, (uint32_t)src_len, src);618 }619 m_bytes.append((const char *)src, src_len);620 }621 622 bool isNotifyPacket = false;623 624 // Parse up the packets into gdb remote packets625 if (!m_bytes.empty()) {626 // end_idx must be one past the last valid packet byte. Start it off with627 // an invalid value that is the same as the current index.628 size_t content_start = 0;629 size_t content_length = 0;630 size_t total_length = 0;631 size_t checksum_idx = std::string::npos;632 633 // Size of packet before it is decompressed, for logging purposes634 size_t original_packet_size = m_bytes.size();635 if (CompressionIsEnabled()) {636 if (!DecompressPacket()) {637 packet.Clear();638 return GDBRemoteCommunication::PacketType::Standard;639 }640 }641 642 switch (m_bytes[0]) {643 case '+': // Look for ack644 case '-': // Look for cancel645 case '\x03': // ^C to halt target646 content_length = total_length = 1; // The command is one byte long...647 break;648 649 case '%': // Async notify packet650 isNotifyPacket = true;651 [[fallthrough]];652 653 case '$':654 // Look for a standard gdb packet?655 {656 size_t hash_pos = m_bytes.find('#');657 if (hash_pos != std::string::npos) {658 if (hash_pos + 2 < m_bytes.size()) {659 checksum_idx = hash_pos + 1;660 // Skip the dollar sign661 content_start = 1;662 // Don't include the # in the content or the $ in the content663 // length664 content_length = hash_pos - 1;665 666 total_length =667 hash_pos + 3; // Skip the # and the two hex checksum bytes668 } else {669 // Checksum bytes aren't all here yet670 content_length = std::string::npos;671 }672 }673 }674 break;675 676 default: {677 // We have an unexpected byte and we need to flush all bad data that is678 // in m_bytes, so we need to find the first byte that is a '+' (ACK), '-'679 // (NACK), \x03 (CTRL+C interrupt), or '$' character (start of packet680 // header) or of course, the end of the data in m_bytes...681 const size_t bytes_len = m_bytes.size();682 bool done = false;683 uint32_t idx;684 for (idx = 1; !done && idx < bytes_len; ++idx) {685 switch (m_bytes[idx]) {686 case '+':687 case '-':688 case '\x03':689 case '%':690 case '$':691 done = true;692 break;693 694 default:695 break;696 }697 }698 LLDB_LOGF(log, "GDBRemoteCommunication::%s tossing %u junk bytes: '%.*s'",699 __FUNCTION__, idx - 1, idx - 1, m_bytes.c_str());700 m_bytes.erase(0, idx - 1);701 } break;702 }703 704 if (content_length == std::string::npos) {705 packet.Clear();706 return GDBRemoteCommunication::PacketType::Invalid;707 } else if (total_length > 0) {708 709 // We have a valid packet...710 assert(content_length <= m_bytes.size());711 assert(total_length <= m_bytes.size());712 assert(content_length <= total_length);713 size_t content_end = content_start + content_length;714 715 bool success = true;716 if (log) {717 // If logging was just enabled and we have history, then dump out what718 // we have to the log so we get the historical context. The Dump() call719 // that logs all of the packet will set a boolean so that we don't dump720 // this more than once721 if (!m_history.DidDumpToLog())722 m_history.Dump(log);723 724 bool binary = false;725 // Only detect binary for packets that start with a '$' and have a726 // '#CC' checksum727 if (m_bytes[0] == '$' && total_length > 4) {728 for (size_t i = 0; !binary && i < total_length; ++i) {729 unsigned char c = m_bytes[i];730 if (!llvm::isPrint(c) && !llvm::isSpace(c)) {731 binary = true;732 }733 }734 }735 if (binary) {736 StreamString strm;737 // Packet header...738 if (CompressionIsEnabled())739 strm.Printf("<%4" PRIu64 ":%" PRIu64 "> read packet: %c",740 (uint64_t)original_packet_size, (uint64_t)total_length,741 m_bytes[0]);742 else743 strm.Printf("<%4" PRIu64 "> read packet: %c",744 (uint64_t)total_length, m_bytes[0]);745 for (size_t i = content_start; i < content_end; ++i) {746 // Remove binary escaped bytes when displaying the packet...747 const char ch = m_bytes[i];748 if (ch == 0x7d) {749 // 0x7d is the escape character. The next character is to be750 // XOR'd with 0x20.751 const char escapee = m_bytes[++i] ^ 0x20;752 strm.Printf("%2.2x", escapee);753 } else {754 strm.Printf("%2.2x", (uint8_t)ch);755 }756 }757 // Packet footer...758 strm.Printf("%c%c%c", m_bytes[total_length - 3],759 m_bytes[total_length - 2], m_bytes[total_length - 1]);760 log->PutString(strm.GetString());761 } else {762 if (CompressionIsEnabled())763 LLDB_LOGF(log, "<%4" PRIu64 ":%" PRIu64 "> read packet: %.*s",764 (uint64_t)original_packet_size, (uint64_t)total_length,765 (int)(total_length), m_bytes.c_str());766 else767 LLDB_LOGF(log, "<%4" PRIu64 "> read packet: %.*s",768 (uint64_t)total_length, (int)(total_length),769 m_bytes.c_str());770 }771 }772 773 m_history.AddPacket(m_bytes, total_length,774 GDBRemotePacket::ePacketTypeRecv, total_length);775 776 // Copy the packet from m_bytes to packet_str expanding the run-length777 // encoding in the process.778 auto maybe_packet_str =779 ExpandRLE(m_bytes.substr(content_start, content_end - content_start));780 if (!maybe_packet_str) {781 m_bytes.erase(0, total_length);782 packet.Clear();783 return GDBRemoteCommunication::PacketType::Invalid;784 }785 packet = StringExtractorGDBRemote(*maybe_packet_str);786 787 if (m_bytes[0] == '$' || m_bytes[0] == '%') {788 assert(checksum_idx < m_bytes.size());789 if (::isxdigit(m_bytes[checksum_idx + 0]) ||790 ::isxdigit(m_bytes[checksum_idx + 1])) {791 if (GetSendAcks()) {792 const char *packet_checksum_cstr = &m_bytes[checksum_idx];793 char packet_checksum = strtol(packet_checksum_cstr, nullptr, 16);794 char actual_checksum = CalculcateChecksum(795 llvm::StringRef(m_bytes).slice(content_start, content_end));796 success = packet_checksum == actual_checksum;797 if (!success) {798 LLDB_LOGF(log,799 "error: checksum mismatch: %.*s expected 0x%2.2x, "800 "got 0x%2.2x",801 (int)(total_length), m_bytes.c_str(),802 (uint8_t)packet_checksum, (uint8_t)actual_checksum);803 }804 // Send the ack or nack if needed805 if (!success)806 SendNack();807 else808 SendAck();809 }810 } else {811 success = false;812 LLDB_LOGF(log, "error: invalid checksum in packet: '%s'\n",813 m_bytes.c_str());814 }815 }816 817 m_bytes.erase(0, total_length);818 packet.SetFilePos(0);819 820 if (isNotifyPacket)821 return GDBRemoteCommunication::PacketType::Notify;822 else823 return GDBRemoteCommunication::PacketType::Standard;824 }825 }826 packet.Clear();827 return GDBRemoteCommunication::PacketType::Invalid;828}829 830Status GDBRemoteCommunication::StartDebugserverProcess(831 std::variant<llvm::StringRef, shared_fd_t> comm,832 ProcessLaunchInfo &launch_info, const Args *inferior_args) {833 Log *log = GetLog(GDBRLog::Process);834 835 Args &debugserver_args = launch_info.GetArguments();836 837#if !defined(__APPLE__)838 // First argument to lldb-server must be mode in which to run.839 debugserver_args.AppendArgument("gdbserver");840#endif841 842 // use native registers, not the GDB registers843 debugserver_args.AppendArgument("--native-regs");844 845 if (launch_info.GetLaunchInSeparateProcessGroup())846 debugserver_args.AppendArgument("--setsid");847 848 llvm::SmallString<128> named_pipe_path;849 // socket_pipe is used by debug server to communicate back either850 // TCP port or domain socket name which it listens on. However, we're not851 // interested in the actualy value here.852 // The only reason for using the pipe is to serve as a synchronization point -853 // once data is written to the pipe, debug server is up and running.854 Pipe socket_pipe;855 856 // If a url is supplied then use it857 if (shared_fd_t *comm_fd = std::get_if<shared_fd_t>(&comm)) {858 LLDB_LOG(log, "debugserver communicates over fd {0}", comm_fd);859 assert(*comm_fd != SharedSocket::kInvalidFD);860 debugserver_args.AppendArgument(llvm::formatv("--fd={0}", *comm_fd).str());861 // Send "comm_fd" down to the inferior so it can use it to communicate back862 // with this process.863 launch_info.AppendDuplicateFileAction((int64_t)*comm_fd, (int64_t)*comm_fd);864 } else {865 llvm::StringRef url = std::get<llvm::StringRef>(comm);866 LLDB_LOG(log, "debugserver listens on: {0}", url);867 debugserver_args.AppendArgument(url);868 869#if defined(__APPLE__)870 // Using a named pipe as debugserver does not support --pipe.871 Status error = socket_pipe.CreateWithUniqueName("debugserver-named-pipe",872 named_pipe_path);873 if (error.Fail()) {874 LLDB_LOG(log, "named pipe creation failed: {0}", error);875 return error;876 }877 debugserver_args.AppendArgument(llvm::StringRef("--named-pipe"));878 debugserver_args.AppendArgument(named_pipe_path);879#else880 // Using an unnamed pipe as it's simpler.881 Status error = socket_pipe.CreateNew();882 if (error.Fail()) {883 LLDB_LOG(log, "unnamed pipe creation failed: {0}", error);884 return error;885 }886 pipe_t write = socket_pipe.GetWritePipe();887 debugserver_args.AppendArgument(llvm::StringRef("--pipe"));888 debugserver_args.AppendArgument(llvm::to_string(write));889 launch_info.AppendDuplicateFileAction((int64_t)write, (int64_t)write);890#endif891 }892 893 Environment host_env = Host::GetEnvironment();894 std::string env_debugserver_log_file =895 host_env.lookup("LLDB_DEBUGSERVER_LOG_FILE");896 if (!env_debugserver_log_file.empty()) {897 debugserver_args.AppendArgument(898 llvm::formatv("--log-file={0}", env_debugserver_log_file).str());899 }900 901#if defined(__APPLE__)902 const char *env_debugserver_log_flags = getenv("LLDB_DEBUGSERVER_LOG_FLAGS");903 if (env_debugserver_log_flags) {904 debugserver_args.AppendArgument(905 llvm::formatv("--log-flags={0}", env_debugserver_log_flags).str());906 }907#else908 std::string env_debugserver_log_channels =909 host_env.lookup("LLDB_SERVER_LOG_CHANNELS");910 if (!env_debugserver_log_channels.empty()) {911 debugserver_args.AppendArgument(912 llvm::formatv("--log-channels={0}", env_debugserver_log_channels)913 .str());914 }915#endif916 917 // Add additional args, starting with LLDB_DEBUGSERVER_EXTRA_ARG_1 until an918 // env var doesn't come back.919 uint32_t env_var_index = 1;920 bool has_env_var;921 do {922 char env_var_name[64];923 snprintf(env_var_name, sizeof(env_var_name),924 "LLDB_DEBUGSERVER_EXTRA_ARG_%" PRIu32, env_var_index++);925 std::string extra_arg = host_env.lookup(env_var_name);926 has_env_var = !extra_arg.empty();927 928 if (has_env_var) {929 debugserver_args.AppendArgument(llvm::StringRef(extra_arg));930 LLDB_LOGF(log,931 "GDBRemoteCommunication::%s adding env var %s contents "932 "to stub command line (%s)",933 __FUNCTION__, env_var_name, extra_arg.c_str());934 }935 } while (has_env_var);936 937 if (inferior_args && inferior_args->GetArgumentCount() > 0) {938 debugserver_args.AppendArgument(llvm::StringRef("--"));939 debugserver_args.AppendArguments(*inferior_args);940 }941 942 // Copy the current environment to the gdbserver/debugserver instance943 launch_info.GetEnvironment() = host_env;944 945 // Close STDIN, STDOUT and STDERR.946 launch_info.AppendCloseFileAction(STDIN_FILENO);947 launch_info.AppendCloseFileAction(STDOUT_FILENO);948 launch_info.AppendCloseFileAction(STDERR_FILENO);949 950 // Redirect STDIN, STDOUT and STDERR to "/dev/null".951 launch_info.AppendSuppressFileAction(STDIN_FILENO, true, false);952 launch_info.AppendSuppressFileAction(STDOUT_FILENO, false, true);953 launch_info.AppendSuppressFileAction(STDERR_FILENO, false, true);954 955 if (log) {956 StreamString string_stream;957 Platform *const platform = nullptr;958 launch_info.Dump(string_stream, platform);959 LLDB_LOG(log, "launch info for gdb-remote stub:\n{0}",960 string_stream.GetData());961 }962 if (Status error = Host::LaunchProcess(launch_info); error.Fail()) {963 LLDB_LOG(log, "launch failed: {0}", error);964 return error;965 }966 967 if (std::holds_alternative<shared_fd_t>(comm))968 return Status();969 970 Status error;971 if (named_pipe_path.size() > 0) {972 error = socket_pipe.OpenAsReader(named_pipe_path);973 if (error.Fail()) {974 LLDB_LOG(log, "failed to open named pipe {0} for reading: {1}",975 named_pipe_path, error);976 }977 }978 979 if (socket_pipe.CanWrite())980 socket_pipe.CloseWriteFileDescriptor();981 assert(socket_pipe.CanRead());982 983 // Read data from the pipe -- and ignore it (see comment above).984 while (error.Success()) {985 char buf[10];986 if (llvm::Expected<size_t> num_bytes =987 socket_pipe.Read(buf, std::size(buf), std::chrono::seconds(10))) {988 if (*num_bytes == 0)989 break;990 } else {991 error = Status::FromError(num_bytes.takeError());992 }993 }994 if (error.Fail()) {995 LLDB_LOG(log, "failed to synchronize on pipe {0}: {1}", named_pipe_path,996 error);997 }998 socket_pipe.Close();999 1000 if (named_pipe_path.size() > 0) {1001 if (Status err = socket_pipe.Delete(named_pipe_path); err.Fail())1002 LLDB_LOG(log, "failed to delete pipe {0}: {1}", named_pipe_path, err);1003 }1004 1005 return error;1006}1007 1008void GDBRemoteCommunication::DumpHistory(Stream &strm) { m_history.Dump(strm); }1009 1010GDBRemoteCommunication::ScopedTimeout::ScopedTimeout(1011 GDBRemoteCommunication &gdb_comm, std::chrono::seconds timeout)1012 : m_gdb_comm(gdb_comm), m_saved_timeout(0), m_timeout_modified(false) {1013 auto curr_timeout = gdb_comm.GetPacketTimeout();1014 // Only update the timeout if the timeout is greater than the current1015 // timeout. If the current timeout is larger, then just use that.1016 if (curr_timeout < timeout) {1017 m_timeout_modified = true;1018 m_saved_timeout = m_gdb_comm.SetPacketTimeout(timeout);1019 }1020}1021 1022GDBRemoteCommunication::ScopedTimeout::~ScopedTimeout() {1023 // Only restore the timeout if we set it in the constructor.1024 if (m_timeout_modified)1025 m_gdb_comm.SetPacketTimeout(m_saved_timeout);1026}1027 1028void llvm::format_provider<GDBRemoteCommunication::PacketResult>::format(1029 const GDBRemoteCommunication::PacketResult &result, raw_ostream &Stream,1030 StringRef Style) {1031 using PacketResult = GDBRemoteCommunication::PacketResult;1032 1033 switch (result) {1034 case PacketResult::Success:1035 Stream << "Success";1036 break;1037 case PacketResult::ErrorSendFailed:1038 Stream << "ErrorSendFailed";1039 break;1040 case PacketResult::ErrorSendAck:1041 Stream << "ErrorSendAck";1042 break;1043 case PacketResult::ErrorReplyFailed:1044 Stream << "ErrorReplyFailed";1045 break;1046 case PacketResult::ErrorReplyTimeout:1047 Stream << "ErrorReplyTimeout";1048 break;1049 case PacketResult::ErrorReplyInvalid:1050 Stream << "ErrorReplyInvalid";1051 break;1052 case PacketResult::ErrorReplyAck:1053 Stream << "ErrorReplyAck";1054 break;1055 case PacketResult::ErrorDisconnected:1056 Stream << "ErrorDisconnected";1057 break;1058 case PacketResult::ErrorNoSequenceLock:1059 Stream << "ErrorNoSequenceLock";1060 break;1061 }1062}1063 1064std::optional<std::string>1065GDBRemoteCommunication::ExpandRLE(std::string packet) {1066 // Reserve enough byte for the most common case (no RLE used).1067 std::string decoded;1068 decoded.reserve(packet.size());1069 for (std::string::const_iterator c = packet.begin(); c != packet.end(); ++c) {1070 if (*c == '*') {1071 if (decoded.empty())1072 return std::nullopt;1073 // '*' indicates RLE. Next character will give us the repeat count and1074 // previous character is what is to be repeated.1075 char char_to_repeat = decoded.back();1076 // Number of time the previous character is repeated.1077 if (++c == packet.end())1078 return std::nullopt;1079 int repeat_count = *c + 3 - ' ';1080 // We have the char_to_repeat and repeat_count. Now push it in the1081 // packet.1082 for (int i = 0; i < repeat_count; ++i)1083 decoded.push_back(char_to_repeat);1084 } else if (*c == 0x7d) {1085 // 0x7d is the escape character. The next character is to be XOR'd with1086 // 0x20.1087 if (++c == packet.end())1088 return std::nullopt;1089 char escapee = *c ^ 0x20;1090 decoded.push_back(escapee);1091 } else {1092 decoded.push_back(*c);1093 }1094 }1095 return decoded;1096}1097