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-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "GDBRemoteCommunication.h"
10
11#include <climits>
12#include <cstring>
13#include <future>
14#include <sys/stat.h>
15
16#include "lldb/Host/Config.h"
17#include "lldb/Host/ConnectionFileDescriptor.h"
18#include "lldb/Host/FileSystem.h"
19#include "lldb/Host/Host.h"
20#include "lldb/Host/HostInfo.h"
21#include "lldb/Host/Pipe.h"
22#include "lldb/Host/ProcessLaunchInfo.h"
23#include "lldb/Host/Socket.h"
24#include "lldb/Host/ThreadLauncher.h"
25#include "lldb/Host/common/TCPSocket.h"
26#include "lldb/Host/posix/ConnectionFileDescriptorPosix.h"
27#include "lldb/Target/Platform.h"
28#include "lldb/Utility/Event.h"
29#include "lldb/Utility/FileSpec.h"
30#include "lldb/Utility/Log.h"
31#include "lldb/Utility/RegularExpression.h"
32#include "lldb/Utility/StreamString.h"
33#include "llvm/ADT/SmallString.h"
34#include "llvm/Support/ScopedPrinter.h"
35
36#include "ProcessGDBRemoteLog.h"
37
38#if defined(__APPLE__)
39#define DEBUGSERVER_BASENAME "debugserver"
40#elif defined(_WIN32)
41#define DEBUGSERVER_BASENAME "lldb-server.exe"
42#else
43#define DEBUGSERVER_BASENAME "lldb-server"
44#endif
45
46#if defined(HAVE_LIBCOMPRESSION)
47#include <compression.h>
48#endif
49
50#if LLVM_ENABLE_ZLIB
51#include <zlib.h>
52#endif
53
54using namespace lldb;
55using namespace lldb_private;
56using namespace lldb_private::process_gdb_remote;
57
58// GDBRemoteCommunication constructor
59GDBRemoteCommunication::GDBRemoteCommunication()
60 : Communication(),
61#ifdef LLDB_CONFIGURATION_DEBUG
62 m_packet_timeout(1000),
63#else
64 m_packet_timeout(1),
65#endif
66 m_echo_number(0), m_supports_qEcho(eLazyBoolCalculate), m_history(512),
67 m_send_acks(true), m_is_platform(false),
68 m_compression_type(CompressionType::None), m_listen_url() {
69}
70
71// Destructor
72GDBRemoteCommunication::~GDBRemoteCommunication() {
73 if (IsConnected()) {
74 Disconnect();
75 }
76
77#if defined(HAVE_LIBCOMPRESSION)
78 if (m_decompression_scratch)
79 free (m_decompression_scratch);
80#endif
81}
82
83char GDBRemoteCommunication::CalculcateChecksum(llvm::StringRef payload) {
84 int checksum = 0;
85
86 for (char c : payload)
87 checksum += c;
88
89 return checksum & 255;
90}
91
92size_t GDBRemoteCommunication::SendAck() {
93 Log *log = GetLog(mask: GDBRLog::Packets);
94 ConnectionStatus status = eConnectionStatusSuccess;
95 char ch = '+';
96 const size_t bytes_written = WriteAll(src: &ch, src_len: 1, status, error_ptr: nullptr);
97 LLDB_LOGF(log, "<%4" PRIu64 "> send packet: %c", (uint64_t)bytes_written, ch);
98 m_history.AddPacket(packet_char: ch, type: GDBRemotePacket::ePacketTypeSend, bytes_transmitted: bytes_written);
99 return bytes_written;
100}
101
102size_t GDBRemoteCommunication::SendNack() {
103 Log *log = GetLog(mask: GDBRLog::Packets);
104 ConnectionStatus status = eConnectionStatusSuccess;
105 char ch = '-';
106 const size_t bytes_written = WriteAll(src: &ch, src_len: 1, status, error_ptr: nullptr);
107 LLDB_LOGF(log, "<%4" PRIu64 "> send packet: %c", (uint64_t)bytes_written, ch);
108 m_history.AddPacket(packet_char: ch, type: GDBRemotePacket::ePacketTypeSend, bytes_transmitted: bytes_written);
109 return bytes_written;
110}
111
112GDBRemoteCommunication::PacketResult
113GDBRemoteCommunication::SendPacketNoLock(llvm::StringRef payload) {
114 StreamString packet(0, 4, eByteOrderBig);
115 packet.PutChar(ch: '$');
116 packet.Write(src: payload.data(), src_len: payload.size());
117 packet.PutChar(ch: '#');
118 packet.PutHex8(uvalue: CalculcateChecksum(payload));
119 std::string packet_str = std::string(packet.GetString());
120
121 return SendRawPacketNoLock(payload: packet_str);
122}
123
124GDBRemoteCommunication::PacketResult
125GDBRemoteCommunication::SendNotificationPacketNoLock(
126 llvm::StringRef notify_type, std::deque<std::string> &queue,
127 llvm::StringRef payload) {
128 PacketResult ret = PacketResult::Success;
129
130 // If there are no notification in the queue, send the notification
131 // packet.
132 if (queue.empty()) {
133 StreamString packet(0, 4, eByteOrderBig);
134 packet.PutChar(ch: '%');
135 packet.Write(src: notify_type.data(), src_len: notify_type.size());
136 packet.PutChar(ch: ':');
137 packet.Write(src: payload.data(), src_len: payload.size());
138 packet.PutChar(ch: '#');
139 packet.PutHex8(uvalue: CalculcateChecksum(payload));
140 ret = SendRawPacketNoLock(payload: packet.GetString(), skip_ack: true);
141 }
142
143 queue.push_back(x: payload.str());
144 return ret;
145}
146
147GDBRemoteCommunication::PacketResult
148GDBRemoteCommunication::SendRawPacketNoLock(llvm::StringRef packet,
149 bool skip_ack) {
150 if (IsConnected()) {
151 Log *log = GetLog(mask: GDBRLog::Packets);
152 ConnectionStatus status = eConnectionStatusSuccess;
153 const char *packet_data = packet.data();
154 const size_t packet_length = packet.size();
155 size_t bytes_written = WriteAll(src: packet_data, src_len: packet_length, status, error_ptr: nullptr);
156 if (log) {
157 size_t binary_start_offset = 0;
158 if (strncmp(s1: packet_data, s2: "$vFile:pwrite:", n: strlen(s: "$vFile:pwrite:")) ==
159 0) {
160 const char *first_comma = strchr(s: packet_data, c: ',');
161 if (first_comma) {
162 const char *second_comma = strchr(s: first_comma + 1, c: ',');
163 if (second_comma)
164 binary_start_offset = second_comma - packet_data + 1;
165 }
166 }
167
168 // If logging was just enabled and we have history, then dump out what we
169 // have to the log so we get the historical context. The Dump() call that
170 // logs all of the packet will set a boolean so that we don't dump this
171 // more than once
172 if (!m_history.DidDumpToLog())
173 m_history.Dump(log);
174
175 if (binary_start_offset) {
176 StreamString strm;
177 // Print non binary data header
178 strm.Printf(format: "<%4" PRIu64 "> send packet: %.*s", (uint64_t)bytes_written,
179 (int)binary_start_offset, packet_data);
180 const uint8_t *p;
181 // Print binary data exactly as sent
182 for (p = (const uint8_t *)packet_data + binary_start_offset; *p != '#';
183 ++p)
184 strm.Printf(format: "\\x%2.2x", *p);
185 // Print the checksum
186 strm.Printf(format: "%*s", (int)3, p);
187 log->PutString(str: strm.GetString());
188 } else
189 LLDB_LOGF(log, "<%4" PRIu64 "> send packet: %.*s",
190 (uint64_t)bytes_written, (int)packet_length, packet_data);
191 }
192
193 m_history.AddPacket(src: packet.str(), src_len: packet_length,
194 type: GDBRemotePacket::ePacketTypeSend, bytes_transmitted: bytes_written);
195
196 if (bytes_written == packet_length) {
197 if (!skip_ack && GetSendAcks())
198 return GetAck();
199 else
200 return PacketResult::Success;
201 } else {
202 LLDB_LOGF(log, "error: failed to send packet: %.*s", (int)packet_length,
203 packet_data);
204 }
205 }
206 return PacketResult::ErrorSendFailed;
207}
208
209GDBRemoteCommunication::PacketResult GDBRemoteCommunication::GetAck() {
210 StringExtractorGDBRemote packet;
211 PacketResult result = WaitForPacketNoLock(response&: packet, timeout: GetPacketTimeout(), sync_on_timeout: false);
212 if (result == PacketResult::Success) {
213 if (packet.GetResponseType() ==
214 StringExtractorGDBRemote::ResponseType::eAck)
215 return PacketResult::Success;
216 else
217 return PacketResult::ErrorSendAck;
218 }
219 return result;
220}
221
222GDBRemoteCommunication::PacketResult
223GDBRemoteCommunication::ReadPacket(StringExtractorGDBRemote &response,
224 Timeout<std::micro> timeout,
225 bool sync_on_timeout) {
226 using ResponseType = StringExtractorGDBRemote::ResponseType;
227
228 Log *log = GetLog(mask: GDBRLog::Packets);
229 for (;;) {
230 PacketResult result =
231 WaitForPacketNoLock(response, timeout, sync_on_timeout);
232 if (result != PacketResult::Success ||
233 (response.GetResponseType() != ResponseType::eAck &&
234 response.GetResponseType() != ResponseType::eNack))
235 return result;
236 LLDB_LOG(log, "discarding spurious `{0}` packet", response.GetStringRef());
237 }
238}
239
240GDBRemoteCommunication::PacketResult
241GDBRemoteCommunication::WaitForPacketNoLock(StringExtractorGDBRemote &packet,
242 Timeout<std::micro> timeout,
243 bool sync_on_timeout) {
244 uint8_t buffer[8192];
245 Status error;
246
247 Log *log = GetLog(mask: GDBRLog::Packets);
248
249 // Check for a packet from our cache first without trying any reading...
250 if (CheckForPacket(src: nullptr, src_len: 0, packet) != PacketType::Invalid)
251 return PacketResult::Success;
252
253 bool timed_out = false;
254 bool disconnected = false;
255 while (IsConnected() && !timed_out) {
256 lldb::ConnectionStatus status = eConnectionStatusNoConnection;
257 size_t bytes_read = Read(dst: buffer, dst_len: sizeof(buffer), timeout, status, error_ptr: &error);
258
259 LLDB_LOGV(log,
260 "Read(buffer, sizeof(buffer), timeout = {0}, "
261 "status = {1}, error = {2}) => bytes_read = {3}",
262 timeout, Communication::ConnectionStatusAsString(status), error,
263 bytes_read);
264
265 if (bytes_read > 0) {
266 if (CheckForPacket(src: buffer, src_len: bytes_read, packet) != PacketType::Invalid)
267 return PacketResult::Success;
268 } else {
269 switch (status) {
270 case eConnectionStatusTimedOut:
271 case eConnectionStatusInterrupted:
272 if (sync_on_timeout) {
273 /// Sync the remote GDB server and make sure we get a response that
274 /// corresponds to what we send.
275 ///
276 /// Sends a "qEcho" packet and makes sure it gets the exact packet
277 /// echoed back. If the qEcho packet isn't supported, we send a qC
278 /// packet and make sure we get a valid thread ID back. We use the
279 /// "qC" packet since its response if very unique: is responds with
280 /// "QC%x" where %x is the thread ID of the current thread. This
281 /// makes the response unique enough from other packet responses to
282 /// ensure we are back on track.
283 ///
284 /// This packet is needed after we time out sending a packet so we
285 /// can ensure that we are getting the response for the packet we
286 /// are sending. There are no sequence IDs in the GDB remote
287 /// protocol (there used to be, but they are not supported anymore)
288 /// so if you timeout sending packet "abc", you might then send
289 /// packet "cde" and get the response for the previous "abc" packet.
290 /// Many responses are "OK" or "" (unsupported) or "EXX" (error) so
291 /// many responses for packets can look like responses for other
292 /// packets. So if we timeout, we need to ensure that we can get
293 /// back on track. If we can't get back on track, we must
294 /// disconnect.
295 bool sync_success = false;
296 bool got_actual_response = false;
297 // We timed out, we need to sync back up with the
298 char echo_packet[32];
299 int echo_packet_len = 0;
300 RegularExpression response_regex;
301
302 if (m_supports_qEcho == eLazyBoolYes) {
303 echo_packet_len = ::snprintf(s: echo_packet, maxlen: sizeof(echo_packet),
304 format: "qEcho:%u", ++m_echo_number);
305 std::string regex_str = "^";
306 regex_str += echo_packet;
307 regex_str += "$";
308 response_regex = RegularExpression(regex_str);
309 } else {
310 echo_packet_len =
311 ::snprintf(s: echo_packet, maxlen: sizeof(echo_packet), format: "qC");
312 response_regex =
313 RegularExpression(llvm::StringRef("^QC[0-9A-Fa-f]+$"));
314 }
315
316 PacketResult echo_packet_result =
317 SendPacketNoLock(payload: llvm::StringRef(echo_packet, echo_packet_len));
318 if (echo_packet_result == PacketResult::Success) {
319 const uint32_t max_retries = 3;
320 uint32_t successful_responses = 0;
321 for (uint32_t i = 0; i < max_retries; ++i) {
322 StringExtractorGDBRemote echo_response;
323 echo_packet_result =
324 WaitForPacketNoLock(packet&: echo_response, timeout, sync_on_timeout: false);
325 if (echo_packet_result == PacketResult::Success) {
326 ++successful_responses;
327 if (response_regex.Execute(string: echo_response.GetStringRef())) {
328 sync_success = true;
329 break;
330 } else if (successful_responses == 1) {
331 // We got something else back as the first successful
332 // response, it probably is the response to the packet we
333 // actually wanted, so copy it over if this is the first
334 // success and continue to try to get the qEcho response
335 packet = echo_response;
336 got_actual_response = true;
337 }
338 } else if (echo_packet_result == PacketResult::ErrorReplyTimeout)
339 continue; // Packet timed out, continue waiting for a response
340 else
341 break; // Something else went wrong getting the packet back, we
342 // failed and are done trying
343 }
344 }
345
346 // We weren't able to sync back up with the server, we must abort
347 // otherwise all responses might not be from the right packets...
348 if (sync_success) {
349 // We timed out, but were able to recover
350 if (got_actual_response) {
351 // We initially timed out, but we did get a response that came in
352 // before the successful reply to our qEcho packet, so lets say
353 // everything is fine...
354 return PacketResult::Success;
355 }
356 } else {
357 disconnected = true;
358 Disconnect();
359 }
360 }
361 timed_out = true;
362 break;
363 case eConnectionStatusSuccess:
364 // printf ("status = success but error = %s\n",
365 // error.AsCString("<invalid>"));
366 break;
367
368 case eConnectionStatusEndOfFile:
369 case eConnectionStatusNoConnection:
370 case eConnectionStatusLostConnection:
371 case eConnectionStatusError:
372 disconnected = true;
373 Disconnect();
374 break;
375 }
376 }
377 }
378 packet.Clear();
379 if (disconnected)
380 return PacketResult::ErrorDisconnected;
381 if (timed_out)
382 return PacketResult::ErrorReplyTimeout;
383 else
384 return PacketResult::ErrorReplyFailed;
385}
386
387bool GDBRemoteCommunication::DecompressPacket() {
388 Log *log = GetLog(mask: GDBRLog::Packets);
389
390 if (!CompressionIsEnabled())
391 return true;
392
393 size_t pkt_size = m_bytes.size();
394
395 // Smallest possible compressed packet is $N#00 - an uncompressed empty
396 // reply, most commonly indicating an unsupported packet. Anything less than
397 // 5 characters, it's definitely not a compressed packet.
398 if (pkt_size < 5)
399 return true;
400
401 if (m_bytes[0] != '$' && m_bytes[0] != '%')
402 return true;
403 if (m_bytes[1] != 'C' && m_bytes[1] != 'N')
404 return true;
405
406 size_t hash_mark_idx = m_bytes.find(c: '#');
407 if (hash_mark_idx == std::string::npos)
408 return true;
409 if (hash_mark_idx + 2 >= m_bytes.size())
410 return true;
411
412 if (!::isxdigit(m_bytes[hash_mark_idx + 1]) ||
413 !::isxdigit(m_bytes[hash_mark_idx + 2]))
414 return true;
415
416 size_t content_length =
417 pkt_size -
418 5; // not counting '$', 'C' | 'N', '#', & the two hex checksum chars
419 size_t content_start = 2; // The first character of the
420 // compressed/not-compressed text of the packet
421 size_t checksum_idx =
422 hash_mark_idx +
423 1; // The first character of the two hex checksum characters
424
425 // Normally size_of_first_packet == m_bytes.size() but m_bytes may contain
426 // multiple packets. size_of_first_packet is the size of the initial packet
427 // which we'll replace with the decompressed version of, leaving the rest of
428 // m_bytes unmodified.
429 size_t size_of_first_packet = hash_mark_idx + 3;
430
431 // Compressed packets ("$C") start with a base10 number which is the size of
432 // the uncompressed payload, then a : and then the compressed data. e.g.
433 // $C1024:<binary>#00 Update content_start and content_length to only include
434 // the <binary> part of the packet.
435
436 uint64_t decompressed_bufsize = ULONG_MAX;
437 if (m_bytes[1] == 'C') {
438 size_t i = content_start;
439 while (i < hash_mark_idx && isdigit(m_bytes[i]))
440 i++;
441 if (i < hash_mark_idx && m_bytes[i] == ':') {
442 i++;
443 content_start = i;
444 content_length = hash_mark_idx - content_start;
445 std::string bufsize_str(m_bytes.data() + 2, i - 2 - 1);
446 errno = 0;
447 decompressed_bufsize = ::strtoul(nptr: bufsize_str.c_str(), endptr: nullptr, base: 10);
448 if (errno != 0 || decompressed_bufsize == ULONG_MAX) {
449 m_bytes.erase(pos: 0, n: size_of_first_packet);
450 return false;
451 }
452 }
453 }
454
455 if (GetSendAcks()) {
456 char packet_checksum_cstr[3];
457 packet_checksum_cstr[0] = m_bytes[checksum_idx];
458 packet_checksum_cstr[1] = m_bytes[checksum_idx + 1];
459 packet_checksum_cstr[2] = '\0';
460 long packet_checksum = strtol(nptr: packet_checksum_cstr, endptr: nullptr, base: 16);
461
462 long actual_checksum = CalculcateChecksum(
463 payload: llvm::StringRef(m_bytes).substr(Start: 1, N: hash_mark_idx - 1));
464 bool success = packet_checksum == actual_checksum;
465 if (!success) {
466 LLDB_LOGF(log,
467 "error: checksum mismatch: %.*s expected 0x%2.2x, got 0x%2.2x",
468 (int)(pkt_size), m_bytes.c_str(), (uint8_t)packet_checksum,
469 (uint8_t)actual_checksum);
470 }
471 // Send the ack or nack if needed
472 if (!success) {
473 SendNack();
474 m_bytes.erase(pos: 0, n: size_of_first_packet);
475 return false;
476 } else {
477 SendAck();
478 }
479 }
480
481 if (m_bytes[1] == 'N') {
482 // This packet was not compressed -- delete the 'N' character at the start
483 // and the packet may be processed as-is.
484 m_bytes.erase(pos: 1, n: 1);
485 return true;
486 }
487
488 // Reverse the gdb-remote binary escaping that was done to the compressed
489 // text to guard characters like '$', '#', '}', etc.
490 std::vector<uint8_t> unescaped_content;
491 unescaped_content.reserve(n: content_length);
492 size_t i = content_start;
493 while (i < hash_mark_idx) {
494 if (m_bytes[i] == '}') {
495 i++;
496 unescaped_content.push_back(x: m_bytes[i] ^ 0x20);
497 } else {
498 unescaped_content.push_back(x: m_bytes[i]);
499 }
500 i++;
501 }
502
503 uint8_t *decompressed_buffer = nullptr;
504 size_t decompressed_bytes = 0;
505
506 if (decompressed_bufsize != ULONG_MAX) {
507 decompressed_buffer = (uint8_t *)malloc(size: decompressed_bufsize);
508 if (decompressed_buffer == nullptr) {
509 m_bytes.erase(pos: 0, n: size_of_first_packet);
510 return false;
511 }
512 }
513
514#if defined(HAVE_LIBCOMPRESSION)
515 if (m_compression_type == CompressionType::ZlibDeflate ||
516 m_compression_type == CompressionType::LZFSE ||
517 m_compression_type == CompressionType::LZ4 ||
518 m_compression_type == CompressionType::LZMA) {
519 compression_algorithm compression_type;
520 if (m_compression_type == CompressionType::LZFSE)
521 compression_type = COMPRESSION_LZFSE;
522 else if (m_compression_type == CompressionType::ZlibDeflate)
523 compression_type = COMPRESSION_ZLIB;
524 else if (m_compression_type == CompressionType::LZ4)
525 compression_type = COMPRESSION_LZ4_RAW;
526 else if (m_compression_type == CompressionType::LZMA)
527 compression_type = COMPRESSION_LZMA;
528
529 if (m_decompression_scratch_type != m_compression_type) {
530 if (m_decompression_scratch) {
531 free (m_decompression_scratch);
532 m_decompression_scratch = nullptr;
533 }
534 size_t scratchbuf_size = 0;
535 if (m_compression_type == CompressionType::LZFSE)
536 scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_LZFSE);
537 else if (m_compression_type == CompressionType::LZ4)
538 scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_LZ4_RAW);
539 else if (m_compression_type == CompressionType::ZlibDeflate)
540 scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_ZLIB);
541 else if (m_compression_type == CompressionType::LZMA)
542 scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_LZMA);
543 else if (m_compression_type == CompressionType::LZFSE)
544 scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_LZFSE);
545 if (scratchbuf_size > 0) {
546 m_decompression_scratch = (void*) malloc (scratchbuf_size);
547 m_decompression_scratch_type = m_compression_type;
548 }
549 }
550
551 if (decompressed_bufsize != ULONG_MAX && decompressed_buffer != nullptr) {
552 decompressed_bytes = compression_decode_buffer(
553 decompressed_buffer, decompressed_bufsize,
554 (uint8_t *)unescaped_content.data(), unescaped_content.size(),
555 m_decompression_scratch, compression_type);
556 }
557 }
558#endif
559
560#if LLVM_ENABLE_ZLIB
561 if (decompressed_bytes == 0 && decompressed_bufsize != ULONG_MAX &&
562 decompressed_buffer != nullptr &&
563 m_compression_type == CompressionType::ZlibDeflate) {
564 z_stream stream;
565 memset(s: &stream, c: 0, n: sizeof(z_stream));
566 stream.next_in = (Bytef *)unescaped_content.data();
567 stream.avail_in = (uInt)unescaped_content.size();
568 stream.total_in = 0;
569 stream.next_out = (Bytef *)decompressed_buffer;
570 stream.avail_out = decompressed_bufsize;
571 stream.total_out = 0;
572 stream.zalloc = Z_NULL;
573 stream.zfree = Z_NULL;
574 stream.opaque = Z_NULL;
575
576 if (inflateInit2(&stream, -15) == Z_OK) {
577 int status = inflate(strm: &stream, Z_NO_FLUSH);
578 inflateEnd(strm: &stream);
579 if (status == Z_STREAM_END) {
580 decompressed_bytes = stream.total_out;
581 }
582 }
583 }
584#endif
585
586 if (decompressed_bytes == 0 || decompressed_buffer == nullptr) {
587 if (decompressed_buffer)
588 free(ptr: decompressed_buffer);
589 m_bytes.erase(pos: 0, n: size_of_first_packet);
590 return false;
591 }
592
593 std::string new_packet;
594 new_packet.reserve(res: decompressed_bytes + 6);
595 new_packet.push_back(c: m_bytes[0]);
596 new_packet.append(s: (const char *)decompressed_buffer, n: decompressed_bytes);
597 new_packet.push_back(c: '#');
598 if (GetSendAcks()) {
599 uint8_t decompressed_checksum = CalculcateChecksum(
600 payload: llvm::StringRef((const char *)decompressed_buffer, decompressed_bytes));
601 char decompressed_checksum_str[3];
602 snprintf(s: decompressed_checksum_str, maxlen: 3, format: "%02x", decompressed_checksum);
603 new_packet.append(s: decompressed_checksum_str);
604 } else {
605 new_packet.push_back(c: '0');
606 new_packet.push_back(c: '0');
607 }
608
609 m_bytes.replace(pos: 0, n1: size_of_first_packet, s: new_packet.data(),
610 n2: new_packet.size());
611
612 free(ptr: decompressed_buffer);
613 return true;
614}
615
616GDBRemoteCommunication::PacketType
617GDBRemoteCommunication::CheckForPacket(const uint8_t *src, size_t src_len,
618 StringExtractorGDBRemote &packet) {
619 // Put the packet data into the buffer in a thread safe fashion
620 std::lock_guard<std::recursive_mutex> guard(m_bytes_mutex);
621
622 Log *log = GetLog(mask: GDBRLog::Packets);
623
624 if (src && src_len > 0) {
625 if (log && log->GetVerbose()) {
626 StreamString s;
627 LLDB_LOGF(log, "GDBRemoteCommunication::%s adding %u bytes: %.*s",
628 __FUNCTION__, (uint32_t)src_len, (uint32_t)src_len, src);
629 }
630 m_bytes.append(s: (const char *)src, n: src_len);
631 }
632
633 bool isNotifyPacket = false;
634
635 // Parse up the packets into gdb remote packets
636 if (!m_bytes.empty()) {
637 // end_idx must be one past the last valid packet byte. Start it off with
638 // an invalid value that is the same as the current index.
639 size_t content_start = 0;
640 size_t content_length = 0;
641 size_t total_length = 0;
642 size_t checksum_idx = std::string::npos;
643
644 // Size of packet before it is decompressed, for logging purposes
645 size_t original_packet_size = m_bytes.size();
646 if (CompressionIsEnabled()) {
647 if (!DecompressPacket()) {
648 packet.Clear();
649 return GDBRemoteCommunication::PacketType::Standard;
650 }
651 }
652
653 switch (m_bytes[0]) {
654 case '+': // Look for ack
655 case '-': // Look for cancel
656 case '\x03': // ^C to halt target
657 content_length = total_length = 1; // The command is one byte long...
658 break;
659
660 case '%': // Async notify packet
661 isNotifyPacket = true;
662 [[fallthrough]];
663
664 case '$':
665 // Look for a standard gdb packet?
666 {
667 size_t hash_pos = m_bytes.find(c: '#');
668 if (hash_pos != std::string::npos) {
669 if (hash_pos + 2 < m_bytes.size()) {
670 checksum_idx = hash_pos + 1;
671 // Skip the dollar sign
672 content_start = 1;
673 // Don't include the # in the content or the $ in the content
674 // length
675 content_length = hash_pos - 1;
676
677 total_length =
678 hash_pos + 3; // Skip the # and the two hex checksum bytes
679 } else {
680 // Checksum bytes aren't all here yet
681 content_length = std::string::npos;
682 }
683 }
684 }
685 break;
686
687 default: {
688 // We have an unexpected byte and we need to flush all bad data that is
689 // in m_bytes, so we need to find the first byte that is a '+' (ACK), '-'
690 // (NACK), \x03 (CTRL+C interrupt), or '$' character (start of packet
691 // header) or of course, the end of the data in m_bytes...
692 const size_t bytes_len = m_bytes.size();
693 bool done = false;
694 uint32_t idx;
695 for (idx = 1; !done && idx < bytes_len; ++idx) {
696 switch (m_bytes[idx]) {
697 case '+':
698 case '-':
699 case '\x03':
700 case '%':
701 case '$':
702 done = true;
703 break;
704
705 default:
706 break;
707 }
708 }
709 LLDB_LOGF(log, "GDBRemoteCommunication::%s tossing %u junk bytes: '%.*s'",
710 __FUNCTION__, idx - 1, idx - 1, m_bytes.c_str());
711 m_bytes.erase(pos: 0, n: idx - 1);
712 } break;
713 }
714
715 if (content_length == std::string::npos) {
716 packet.Clear();
717 return GDBRemoteCommunication::PacketType::Invalid;
718 } else if (total_length > 0) {
719
720 // We have a valid packet...
721 assert(content_length <= m_bytes.size());
722 assert(total_length <= m_bytes.size());
723 assert(content_length <= total_length);
724 size_t content_end = content_start + content_length;
725
726 bool success = true;
727 if (log) {
728 // If logging was just enabled and we have history, then dump out what
729 // we have to the log so we get the historical context. The Dump() call
730 // that logs all of the packet will set a boolean so that we don't dump
731 // this more than once
732 if (!m_history.DidDumpToLog())
733 m_history.Dump(log);
734
735 bool binary = false;
736 // Only detect binary for packets that start with a '$' and have a
737 // '#CC' checksum
738 if (m_bytes[0] == '$' && total_length > 4) {
739 for (size_t i = 0; !binary && i < total_length; ++i) {
740 unsigned char c = m_bytes[i];
741 if (!llvm::isPrint(C: c) && !llvm::isSpace(C: c)) {
742 binary = true;
743 }
744 }
745 }
746 if (binary) {
747 StreamString strm;
748 // Packet header...
749 if (CompressionIsEnabled())
750 strm.Printf(format: "<%4" PRIu64 ":%" PRIu64 "> read packet: %c",
751 (uint64_t)original_packet_size, (uint64_t)total_length,
752 m_bytes[0]);
753 else
754 strm.Printf(format: "<%4" PRIu64 "> read packet: %c",
755 (uint64_t)total_length, m_bytes[0]);
756 for (size_t i = content_start; i < content_end; ++i) {
757 // Remove binary escaped bytes when displaying the packet...
758 const char ch = m_bytes[i];
759 if (ch == 0x7d) {
760 // 0x7d is the escape character. The next character is to be
761 // XOR'd with 0x20.
762 const char escapee = m_bytes[++i] ^ 0x20;
763 strm.Printf(format: "%2.2x", escapee);
764 } else {
765 strm.Printf(format: "%2.2x", (uint8_t)ch);
766 }
767 }
768 // Packet footer...
769 strm.Printf(format: "%c%c%c", m_bytes[total_length - 3],
770 m_bytes[total_length - 2], m_bytes[total_length - 1]);
771 log->PutString(str: strm.GetString());
772 } else {
773 if (CompressionIsEnabled())
774 LLDB_LOGF(log, "<%4" PRIu64 ":%" PRIu64 "> read packet: %.*s",
775 (uint64_t)original_packet_size, (uint64_t)total_length,
776 (int)(total_length), m_bytes.c_str());
777 else
778 LLDB_LOGF(log, "<%4" PRIu64 "> read packet: %.*s",
779 (uint64_t)total_length, (int)(total_length),
780 m_bytes.c_str());
781 }
782 }
783
784 m_history.AddPacket(src: m_bytes, src_len: total_length,
785 type: GDBRemotePacket::ePacketTypeRecv, bytes_transmitted: total_length);
786
787 // Copy the packet from m_bytes to packet_str expanding the run-length
788 // encoding in the process.
789 std ::string packet_str =
790 ExpandRLE(m_bytes.substr(pos: content_start, n: content_end - content_start));
791 packet = StringExtractorGDBRemote(packet_str);
792
793 if (m_bytes[0] == '$' || m_bytes[0] == '%') {
794 assert(checksum_idx < m_bytes.size());
795 if (::isxdigit(m_bytes[checksum_idx + 0]) ||
796 ::isxdigit(m_bytes[checksum_idx + 1])) {
797 if (GetSendAcks()) {
798 const char *packet_checksum_cstr = &m_bytes[checksum_idx];
799 char packet_checksum = strtol(nptr: packet_checksum_cstr, endptr: nullptr, base: 16);
800 char actual_checksum = CalculcateChecksum(
801 payload: llvm::StringRef(m_bytes).slice(Start: content_start, End: content_end));
802 success = packet_checksum == actual_checksum;
803 if (!success) {
804 LLDB_LOGF(log,
805 "error: checksum mismatch: %.*s expected 0x%2.2x, "
806 "got 0x%2.2x",
807 (int)(total_length), m_bytes.c_str(),
808 (uint8_t)packet_checksum, (uint8_t)actual_checksum);
809 }
810 // Send the ack or nack if needed
811 if (!success)
812 SendNack();
813 else
814 SendAck();
815 }
816 } else {
817 success = false;
818 LLDB_LOGF(log, "error: invalid checksum in packet: '%s'\n",
819 m_bytes.c_str());
820 }
821 }
822
823 m_bytes.erase(pos: 0, n: total_length);
824 packet.SetFilePos(0);
825
826 if (isNotifyPacket)
827 return GDBRemoteCommunication::PacketType::Notify;
828 else
829 return GDBRemoteCommunication::PacketType::Standard;
830 }
831 }
832 packet.Clear();
833 return GDBRemoteCommunication::PacketType::Invalid;
834}
835
836Status GDBRemoteCommunication::StartListenThread(const char *hostname,
837 uint16_t port) {
838 if (m_listen_thread.IsJoinable())
839 return Status("listen thread already running");
840
841 char listen_url[512];
842 if (hostname && hostname[0])
843 snprintf(s: listen_url, maxlen: sizeof(listen_url), format: "listen://%s:%i", hostname, port);
844 else
845 snprintf(s: listen_url, maxlen: sizeof(listen_url), format: "listen://%i", port);
846 m_listen_url = listen_url;
847 SetConnection(std::make_unique<ConnectionFileDescriptor>());
848 llvm::Expected<HostThread> listen_thread = ThreadLauncher::LaunchThread(
849 name: listen_url, thread_function: [this] { return GDBRemoteCommunication::ListenThread(); });
850 if (!listen_thread)
851 return Status(listen_thread.takeError());
852 m_listen_thread = *listen_thread;
853
854 return Status();
855}
856
857bool GDBRemoteCommunication::JoinListenThread() {
858 if (m_listen_thread.IsJoinable())
859 m_listen_thread.Join(result: nullptr);
860 return true;
861}
862
863lldb::thread_result_t GDBRemoteCommunication::ListenThread() {
864 Status error;
865 ConnectionFileDescriptor *connection =
866 (ConnectionFileDescriptor *)GetConnection();
867
868 if (connection) {
869 // Do the listen on another thread so we can continue on...
870 if (connection->Connect(
871 url: m_listen_url.c_str(),
872 socket_id_callback: [this](llvm::StringRef port_str) {
873 uint16_t port = 0;
874 llvm::to_integer(S: port_str, Num&: port, Base: 10);
875 m_port_promise.set_value(port);
876 },
877 error_ptr: &error) != eConnectionStatusSuccess)
878 SetConnection(nullptr);
879 }
880 return {};
881}
882
883Status GDBRemoteCommunication::StartDebugserverProcess(
884 const char *url, Platform *platform, ProcessLaunchInfo &launch_info,
885 uint16_t *port, const Args *inferior_args, int pass_comm_fd) {
886 Log *log = GetLog(mask: GDBRLog::Process);
887 LLDB_LOGF(log, "GDBRemoteCommunication::%s(url=%s, port=%" PRIu16 ")",
888 __FUNCTION__, url ? url : "<empty>", port ? *port : uint16_t(0));
889
890 Status error;
891 // If we locate debugserver, keep that located version around
892 static FileSpec g_debugserver_file_spec;
893
894 char debugserver_path[PATH_MAX];
895 FileSpec &debugserver_file_spec = launch_info.GetExecutableFile();
896
897 Environment host_env = Host::GetEnvironment();
898
899 // Always check to see if we have an environment override for the path to the
900 // debugserver to use and use it if we do.
901 std::string env_debugserver_path = host_env.lookup(Key: "LLDB_DEBUGSERVER_PATH");
902 if (!env_debugserver_path.empty()) {
903 debugserver_file_spec.SetFile(path: env_debugserver_path,
904 style: FileSpec::Style::native);
905 LLDB_LOGF(log,
906 "GDBRemoteCommunication::%s() gdb-remote stub exe path set "
907 "from environment variable: %s",
908 __FUNCTION__, env_debugserver_path.c_str());
909 } else
910 debugserver_file_spec = g_debugserver_file_spec;
911 bool debugserver_exists =
912 FileSystem::Instance().Exists(file_spec: debugserver_file_spec);
913 if (!debugserver_exists) {
914 // The debugserver binary is in the LLDB.framework/Resources directory.
915 debugserver_file_spec = HostInfo::GetSupportExeDir();
916 if (debugserver_file_spec) {
917 debugserver_file_spec.AppendPathComponent(DEBUGSERVER_BASENAME);
918 debugserver_exists = FileSystem::Instance().Exists(file_spec: debugserver_file_spec);
919 if (debugserver_exists) {
920 LLDB_LOGF(log,
921 "GDBRemoteCommunication::%s() found gdb-remote stub exe '%s'",
922 __FUNCTION__, debugserver_file_spec.GetPath().c_str());
923
924 g_debugserver_file_spec = debugserver_file_spec;
925 } else {
926 if (platform)
927 debugserver_file_spec =
928 platform->LocateExecutable(DEBUGSERVER_BASENAME);
929 else
930 debugserver_file_spec.Clear();
931 if (debugserver_file_spec) {
932 // Platform::LocateExecutable() wouldn't return a path if it doesn't
933 // exist
934 debugserver_exists = true;
935 } else {
936 LLDB_LOGF(log,
937 "GDBRemoteCommunication::%s() could not find "
938 "gdb-remote stub exe '%s'",
939 __FUNCTION__, debugserver_file_spec.GetPath().c_str());
940 }
941 // Don't cache the platform specific GDB server binary as it could
942 // change from platform to platform
943 g_debugserver_file_spec.Clear();
944 }
945 }
946 }
947
948 if (debugserver_exists) {
949 debugserver_file_spec.GetPath(path: debugserver_path, max_path_length: sizeof(debugserver_path));
950
951 Args &debugserver_args = launch_info.GetArguments();
952 debugserver_args.Clear();
953
954 // Start args with "debugserver /file/path -r --"
955 debugserver_args.AppendArgument(arg_str: llvm::StringRef(debugserver_path));
956
957#if !defined(__APPLE__)
958 // First argument to lldb-server must be mode in which to run.
959 debugserver_args.AppendArgument(arg_str: llvm::StringRef("gdbserver"));
960#endif
961
962 // If a url is supplied then use it
963 if (url)
964 debugserver_args.AppendArgument(arg_str: llvm::StringRef(url));
965
966 if (pass_comm_fd >= 0) {
967 StreamString fd_arg;
968 fd_arg.Printf(format: "--fd=%i", pass_comm_fd);
969 debugserver_args.AppendArgument(arg_str: fd_arg.GetString());
970 // Send "pass_comm_fd" down to the inferior so it can use it to
971 // communicate back with this process
972 launch_info.AppendDuplicateFileAction(fd: pass_comm_fd, dup_fd: pass_comm_fd);
973 }
974
975 // use native registers, not the GDB registers
976 debugserver_args.AppendArgument(arg_str: llvm::StringRef("--native-regs"));
977
978 if (launch_info.GetLaunchInSeparateProcessGroup()) {
979 debugserver_args.AppendArgument(arg_str: llvm::StringRef("--setsid"));
980 }
981
982 llvm::SmallString<128> named_pipe_path;
983 // socket_pipe is used by debug server to communicate back either
984 // TCP port or domain socket name which it listens on.
985 // The second purpose of the pipe to serve as a synchronization point -
986 // once data is written to the pipe, debug server is up and running.
987 Pipe socket_pipe;
988
989 // port is null when debug server should listen on domain socket - we're
990 // not interested in port value but rather waiting for debug server to
991 // become available.
992 if (pass_comm_fd == -1) {
993 if (url) {
994// Create a temporary file to get the stdout/stderr and redirect the output of
995// the command into this file. We will later read this file if all goes well
996// and fill the data into "command_output_ptr"
997#if defined(__APPLE__)
998 // Binding to port zero, we need to figure out what port it ends up
999 // using using a named pipe...
1000 error = socket_pipe.CreateWithUniqueName("debugserver-named-pipe",
1001 false, named_pipe_path);
1002 if (error.Fail()) {
1003 LLDB_LOGF(log,
1004 "GDBRemoteCommunication::%s() "
1005 "named pipe creation failed: %s",
1006 __FUNCTION__, error.AsCString());
1007 return error;
1008 }
1009 debugserver_args.AppendArgument(llvm::StringRef("--named-pipe"));
1010 debugserver_args.AppendArgument(named_pipe_path);
1011#else
1012 // Binding to port zero, we need to figure out what port it ends up
1013 // using using an unnamed pipe...
1014 error = socket_pipe.CreateNew(child_process_inherit: true);
1015 if (error.Fail()) {
1016 LLDB_LOGF(log,
1017 "GDBRemoteCommunication::%s() "
1018 "unnamed pipe creation failed: %s",
1019 __FUNCTION__, error.AsCString());
1020 return error;
1021 }
1022 pipe_t write = socket_pipe.GetWritePipe();
1023 debugserver_args.AppendArgument(arg_str: llvm::StringRef("--pipe"));
1024 debugserver_args.AppendArgument(arg_str: llvm::to_string(Value: write));
1025 launch_info.AppendCloseFileAction(fd: socket_pipe.GetReadFileDescriptor());
1026#endif
1027 } else {
1028 // No host and port given, so lets listen on our end and make the
1029 // debugserver connect to us..
1030 error = StartListenThread(hostname: "127.0.0.1", port: 0);
1031 if (error.Fail()) {
1032 LLDB_LOGF(log,
1033 "GDBRemoteCommunication::%s() unable to start listen "
1034 "thread: %s",
1035 __FUNCTION__, error.AsCString());
1036 return error;
1037 }
1038
1039 // Wait for 10 seconds to resolve the bound port
1040 std::future<uint16_t> port_future = m_port_promise.get_future();
1041 uint16_t port_ = port_future.wait_for(rel: std::chrono::seconds(10)) ==
1042 std::future_status::ready
1043 ? port_future.get()
1044 : 0;
1045 if (port_ > 0) {
1046 char port_cstr[32];
1047 snprintf(s: port_cstr, maxlen: sizeof(port_cstr), format: "127.0.0.1:%i", port_);
1048 // Send the host and port down that debugserver and specify an option
1049 // so that it connects back to the port we are listening to in this
1050 // process
1051 debugserver_args.AppendArgument(arg_str: llvm::StringRef("--reverse-connect"));
1052 debugserver_args.AppendArgument(arg_str: llvm::StringRef(port_cstr));
1053 if (port)
1054 *port = port_;
1055 } else {
1056 error.SetErrorString("failed to bind to port 0 on 127.0.0.1");
1057 LLDB_LOGF(log, "GDBRemoteCommunication::%s() failed: %s",
1058 __FUNCTION__, error.AsCString());
1059 return error;
1060 }
1061 }
1062 }
1063 std::string env_debugserver_log_file =
1064 host_env.lookup(Key: "LLDB_DEBUGSERVER_LOG_FILE");
1065 if (!env_debugserver_log_file.empty()) {
1066 debugserver_args.AppendArgument(
1067 arg_str: llvm::formatv(Fmt: "--log-file={0}", Vals&: env_debugserver_log_file).str());
1068 }
1069
1070#if defined(__APPLE__)
1071 const char *env_debugserver_log_flags =
1072 getenv("LLDB_DEBUGSERVER_LOG_FLAGS");
1073 if (env_debugserver_log_flags) {
1074 debugserver_args.AppendArgument(
1075 llvm::formatv("--log-flags={0}", env_debugserver_log_flags).str());
1076 }
1077#else
1078 std::string env_debugserver_log_channels =
1079 host_env.lookup(Key: "LLDB_SERVER_LOG_CHANNELS");
1080 if (!env_debugserver_log_channels.empty()) {
1081 debugserver_args.AppendArgument(
1082 arg_str: llvm::formatv(Fmt: "--log-channels={0}", Vals&: env_debugserver_log_channels)
1083 .str());
1084 }
1085#endif
1086
1087 // Add additional args, starting with LLDB_DEBUGSERVER_EXTRA_ARG_1 until an
1088 // env var doesn't come back.
1089 uint32_t env_var_index = 1;
1090 bool has_env_var;
1091 do {
1092 char env_var_name[64];
1093 snprintf(s: env_var_name, maxlen: sizeof(env_var_name),
1094 format: "LLDB_DEBUGSERVER_EXTRA_ARG_%" PRIu32, env_var_index++);
1095 std::string extra_arg = host_env.lookup(Key: env_var_name);
1096 has_env_var = !extra_arg.empty();
1097
1098 if (has_env_var) {
1099 debugserver_args.AppendArgument(arg_str: llvm::StringRef(extra_arg));
1100 LLDB_LOGF(log,
1101 "GDBRemoteCommunication::%s adding env var %s contents "
1102 "to stub command line (%s)",
1103 __FUNCTION__, env_var_name, extra_arg.c_str());
1104 }
1105 } while (has_env_var);
1106
1107 if (inferior_args && inferior_args->GetArgumentCount() > 0) {
1108 debugserver_args.AppendArgument(arg_str: llvm::StringRef("--"));
1109 debugserver_args.AppendArguments(rhs: *inferior_args);
1110 }
1111
1112 // Copy the current environment to the gdbserver/debugserver instance
1113 launch_info.GetEnvironment() = host_env;
1114
1115 // Close STDIN, STDOUT and STDERR.
1116 launch_info.AppendCloseFileAction(STDIN_FILENO);
1117 launch_info.AppendCloseFileAction(STDOUT_FILENO);
1118 launch_info.AppendCloseFileAction(STDERR_FILENO);
1119
1120 // Redirect STDIN, STDOUT and STDERR to "/dev/null".
1121 launch_info.AppendSuppressFileAction(STDIN_FILENO, read: true, write: false);
1122 launch_info.AppendSuppressFileAction(STDOUT_FILENO, read: false, write: true);
1123 launch_info.AppendSuppressFileAction(STDERR_FILENO, read: false, write: true);
1124
1125 if (log) {
1126 StreamString string_stream;
1127 Platform *const platform = nullptr;
1128 launch_info.Dump(s&: string_stream, platform);
1129 LLDB_LOGF(log, "launch info for gdb-remote stub:\n%s",
1130 string_stream.GetData());
1131 }
1132 error = Host::LaunchProcess(launch_info);
1133
1134 if (error.Success() &&
1135 (launch_info.GetProcessID() != LLDB_INVALID_PROCESS_ID) &&
1136 pass_comm_fd == -1) {
1137 if (named_pipe_path.size() > 0) {
1138 error = socket_pipe.OpenAsReader(name: named_pipe_path, child_process_inherit: false);
1139 if (error.Fail())
1140 LLDB_LOGF(log,
1141 "GDBRemoteCommunication::%s() "
1142 "failed to open named pipe %s for reading: %s",
1143 __FUNCTION__, named_pipe_path.c_str(), error.AsCString());
1144 }
1145
1146 if (socket_pipe.CanWrite())
1147 socket_pipe.CloseWriteFileDescriptor();
1148 if (socket_pipe.CanRead()) {
1149 char port_cstr[PATH_MAX] = {0};
1150 port_cstr[0] = '\0';
1151 size_t num_bytes = sizeof(port_cstr);
1152 // Read port from pipe with 10 second timeout.
1153 error = socket_pipe.ReadWithTimeout(
1154 buf: port_cstr, size: num_bytes, timeout: std::chrono::seconds{10}, bytes_read&: num_bytes);
1155 if (error.Success() && (port != nullptr)) {
1156 assert(num_bytes > 0 && port_cstr[num_bytes - 1] == '\0');
1157 uint16_t child_port = 0;
1158 // FIXME: improve error handling
1159 llvm::to_integer(S: port_cstr, Num&: child_port);
1160 if (*port == 0 || *port == child_port) {
1161 *port = child_port;
1162 LLDB_LOGF(log,
1163 "GDBRemoteCommunication::%s() "
1164 "debugserver listens %u port",
1165 __FUNCTION__, *port);
1166 } else {
1167 LLDB_LOGF(log,
1168 "GDBRemoteCommunication::%s() "
1169 "debugserver listening on port "
1170 "%d but requested port was %d",
1171 __FUNCTION__, (uint32_t)child_port, (uint32_t)(*port));
1172 }
1173 } else {
1174 LLDB_LOGF(log,
1175 "GDBRemoteCommunication::%s() "
1176 "failed to read a port value from pipe %s: %s",
1177 __FUNCTION__, named_pipe_path.c_str(), error.AsCString());
1178 }
1179 socket_pipe.Close();
1180 }
1181
1182 if (named_pipe_path.size() > 0) {
1183 const auto err = socket_pipe.Delete(name: named_pipe_path);
1184 if (err.Fail()) {
1185 LLDB_LOGF(log,
1186 "GDBRemoteCommunication::%s failed to delete pipe %s: %s",
1187 __FUNCTION__, named_pipe_path.c_str(), err.AsCString());
1188 }
1189 }
1190
1191 // Make sure we actually connect with the debugserver...
1192 JoinListenThread();
1193 }
1194 } else {
1195 error.SetErrorStringWithFormat("unable to locate " DEBUGSERVER_BASENAME);
1196 }
1197
1198 if (error.Fail()) {
1199 LLDB_LOGF(log, "GDBRemoteCommunication::%s() failed: %s", __FUNCTION__,
1200 error.AsCString());
1201 }
1202
1203 return error;
1204}
1205
1206void GDBRemoteCommunication::DumpHistory(Stream &strm) { m_history.Dump(strm); }
1207
1208llvm::Error
1209GDBRemoteCommunication::ConnectLocally(GDBRemoteCommunication &client,
1210 GDBRemoteCommunication &server) {
1211 const bool child_processes_inherit = false;
1212 const int backlog = 5;
1213 TCPSocket listen_socket(true, child_processes_inherit);
1214 if (llvm::Error error =
1215 listen_socket.Listen(name: "localhost:0", backlog).ToError())
1216 return error;
1217
1218 Socket *accept_socket = nullptr;
1219 std::future<Status> accept_status = std::async(
1220 policy: std::launch::async, fn: [&] { return listen_socket.Accept(conn_socket&: accept_socket); });
1221
1222 llvm::SmallString<32> remote_addr;
1223 llvm::raw_svector_ostream(remote_addr)
1224 << "connect://localhost:" << listen_socket.GetLocalPortNumber();
1225
1226 std::unique_ptr<ConnectionFileDescriptor> conn_up(
1227 new ConnectionFileDescriptor());
1228 Status status;
1229 if (conn_up->Connect(url: remote_addr, error_ptr: &status) != lldb::eConnectionStatusSuccess)
1230 return llvm::createStringError(EC: llvm::inconvertibleErrorCode(),
1231 Fmt: "Unable to connect: %s", Vals: status.AsCString());
1232
1233 client.SetConnection(std::move(conn_up));
1234 if (llvm::Error error = accept_status.get().ToError())
1235 return error;
1236
1237 server.SetConnection(
1238 std::make_unique<ConnectionFileDescriptor>(args&: accept_socket));
1239 return llvm::Error::success();
1240}
1241
1242GDBRemoteCommunication::ScopedTimeout::ScopedTimeout(
1243 GDBRemoteCommunication &gdb_comm, std::chrono::seconds timeout)
1244 : m_gdb_comm(gdb_comm), m_saved_timeout(0), m_timeout_modified(false) {
1245 auto curr_timeout = gdb_comm.GetPacketTimeout();
1246 // Only update the timeout if the timeout is greater than the current
1247 // timeout. If the current timeout is larger, then just use that.
1248 if (curr_timeout < timeout) {
1249 m_timeout_modified = true;
1250 m_saved_timeout = m_gdb_comm.SetPacketTimeout(timeout);
1251 }
1252}
1253
1254GDBRemoteCommunication::ScopedTimeout::~ScopedTimeout() {
1255 // Only restore the timeout if we set it in the constructor.
1256 if (m_timeout_modified)
1257 m_gdb_comm.SetPacketTimeout(m_saved_timeout);
1258}
1259
1260void llvm::format_provider<GDBRemoteCommunication::PacketResult>::format(
1261 const GDBRemoteCommunication::PacketResult &result, raw_ostream &Stream,
1262 StringRef Style) {
1263 using PacketResult = GDBRemoteCommunication::PacketResult;
1264
1265 switch (result) {
1266 case PacketResult::Success:
1267 Stream << "Success";
1268 break;
1269 case PacketResult::ErrorSendFailed:
1270 Stream << "ErrorSendFailed";
1271 break;
1272 case PacketResult::ErrorSendAck:
1273 Stream << "ErrorSendAck";
1274 break;
1275 case PacketResult::ErrorReplyFailed:
1276 Stream << "ErrorReplyFailed";
1277 break;
1278 case PacketResult::ErrorReplyTimeout:
1279 Stream << "ErrorReplyTimeout";
1280 break;
1281 case PacketResult::ErrorReplyInvalid:
1282 Stream << "ErrorReplyInvalid";
1283 break;
1284 case PacketResult::ErrorReplyAck:
1285 Stream << "ErrorReplyAck";
1286 break;
1287 case PacketResult::ErrorDisconnected:
1288 Stream << "ErrorDisconnected";
1289 break;
1290 case PacketResult::ErrorNoSequenceLock:
1291 Stream << "ErrorNoSequenceLock";
1292 break;
1293 }
1294}
1295
1296std::string GDBRemoteCommunication::ExpandRLE(std::string packet) {
1297 // Reserve enough byte for the most common case (no RLE used).
1298 std::string decoded;
1299 decoded.reserve(res: packet.size());
1300 for (std::string::const_iterator c = packet.begin(); c != packet.end(); ++c) {
1301 if (*c == '*') {
1302 // '*' indicates RLE. Next character will give us the repeat count and
1303 // previous character is what is to be repeated.
1304 char char_to_repeat = decoded.back();
1305 // Number of time the previous character is repeated.
1306 int repeat_count = *++c + 3 - ' ';
1307 // We have the char_to_repeat and repeat_count. Now push it in the
1308 // packet.
1309 for (int i = 0; i < repeat_count; ++i)
1310 decoded.push_back(c: char_to_repeat);
1311 } else if (*c == 0x7d) {
1312 // 0x7d is the escape character. The next character is to be XOR'd with
1313 // 0x20.
1314 char escapee = *++c ^ 0x20;
1315 decoded.push_back(c: escapee);
1316 } else {
1317 decoded.push_back(c: *c);
1318 }
1319 }
1320 return decoded;
1321}
1322

source code of lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp