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#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/HostInfo.h"
15#include "lldb/Host/Pipe.h"
16#include "lldb/Host/ProcessLaunchInfo.h"
17#include "lldb/Host/Socket.h"
18#include "lldb/Host/common/TCPSocket.h"
19#include "lldb/Host/posix/ConnectionFileDescriptorPosix.h"
20#include "lldb/Target/Platform.h"
21#include "lldb/Utility/Event.h"
22#include "lldb/Utility/FileSpec.h"
23#include "lldb/Utility/Log.h"
24#include "lldb/Utility/RegularExpression.h"
25#include "lldb/Utility/StreamString.h"
26#include "llvm/ADT/SmallString.h"
27#include "llvm/ADT/StringRef.h"
28#include "llvm/Config/llvm-config.h" // for LLVM_ENABLE_ZLIB
29#include "llvm/Support/Error.h"
30#include "llvm/Support/ScopedPrinter.h"
31#include <climits>
32#include <cstring>
33#include <sys/stat.h>
34
35#if defined(__APPLE__)
36#define DEBUGSERVER_BASENAME "debugserver"
37#elif defined(_WIN32)
38#define DEBUGSERVER_BASENAME "lldb-server.exe"
39#else
40#define DEBUGSERVER_BASENAME "lldb-server"
41#endif
42
43#if HAVE_LIBCOMPRESSION
44#include <compression.h>
45#endif
46
47#if LLVM_ENABLE_ZLIB
48#include <zlib.h>
49#endif
50
51using namespace lldb;
52using namespace lldb_private;
53using namespace lldb_private::process_gdb_remote;
54
55// GDBRemoteCommunication constructor
56GDBRemoteCommunication::GDBRemoteCommunication()
57 : Communication(),
58#ifdef LLDB_CONFIGURATION_DEBUG
59 m_packet_timeout(1000),
60#else
61 m_packet_timeout(1),
62#endif
63 m_echo_number(0), m_supports_qEcho(eLazyBoolCalculate), m_history(512),
64 m_send_acks(true), m_is_platform(false),
65 m_compression_type(CompressionType::None) {
66}
67
68// Destructor
69GDBRemoteCommunication::~GDBRemoteCommunication() {
70 if (IsConnected()) {
71 Disconnect();
72 }
73
74#if HAVE_LIBCOMPRESSION
75 if (m_decompression_scratch)
76 free (m_decompression_scratch);
77#endif
78}
79
80char GDBRemoteCommunication::CalculcateChecksum(llvm::StringRef payload) {
81 int checksum = 0;
82
83 for (char c : payload)
84 checksum += c;
85
86 return checksum & 255;
87}
88
89size_t GDBRemoteCommunication::SendAck() {
90 Log *log = GetLog(mask: GDBRLog::Packets);
91 ConnectionStatus status = eConnectionStatusSuccess;
92 char ch = '+';
93 const size_t bytes_written = WriteAll(src: &ch, src_len: 1, status, error_ptr: nullptr);
94 LLDB_LOGF(log, "<%4" PRIu64 "> send packet: %c", (uint64_t)bytes_written, ch);
95 m_history.AddPacket(packet_char: ch, type: GDBRemotePacket::ePacketTypeSend, bytes_transmitted: bytes_written);
96 return bytes_written;
97}
98
99size_t GDBRemoteCommunication::SendNack() {
100 Log *log = GetLog(mask: GDBRLog::Packets);
101 ConnectionStatus status = eConnectionStatusSuccess;
102 char ch = '-';
103 const size_t bytes_written = WriteAll(src: &ch, src_len: 1, status, error_ptr: nullptr);
104 LLDB_LOGF(log, "<%4" PRIu64 "> send packet: %c", (uint64_t)bytes_written, ch);
105 m_history.AddPacket(packet_char: ch, type: GDBRemotePacket::ePacketTypeSend, bytes_transmitted: bytes_written);
106 return bytes_written;
107}
108
109GDBRemoteCommunication::PacketResult
110GDBRemoteCommunication::SendPacketNoLock(llvm::StringRef payload) {
111 StreamString packet(0, 4, eByteOrderBig);
112 packet.PutChar(ch: '$');
113 packet.Write(src: payload.data(), src_len: payload.size());
114 packet.PutChar(ch: '#');
115 packet.PutHex8(uvalue: CalculcateChecksum(payload));
116 std::string packet_str = std::string(packet.GetString());
117
118 return SendRawPacketNoLock(payload: packet_str);
119}
120
121GDBRemoteCommunication::PacketResult
122GDBRemoteCommunication::SendNotificationPacketNoLock(
123 llvm::StringRef notify_type, std::deque<std::string> &queue,
124 llvm::StringRef payload) {
125 PacketResult ret = PacketResult::Success;
126
127 // If there are no notification in the queue, send the notification
128 // packet.
129 if (queue.empty()) {
130 StreamString packet(0, 4, eByteOrderBig);
131 packet.PutChar(ch: '%');
132 packet.Write(src: notify_type.data(), src_len: notify_type.size());
133 packet.PutChar(ch: ':');
134 packet.Write(src: payload.data(), src_len: payload.size());
135 packet.PutChar(ch: '#');
136 packet.PutHex8(uvalue: CalculcateChecksum(payload));
137 ret = SendRawPacketNoLock(payload: packet.GetString(), skip_ack: true);
138 }
139
140 queue.push_back(x: payload.str());
141 return ret;
142}
143
144GDBRemoteCommunication::PacketResult
145GDBRemoteCommunication::SendRawPacketNoLock(llvm::StringRef packet,
146 bool skip_ack) {
147 if (IsConnected()) {
148 Log *log = GetLog(mask: GDBRLog::Packets);
149 ConnectionStatus status = eConnectionStatusSuccess;
150 const char *packet_data = packet.data();
151 const size_t packet_length = packet.size();
152 size_t bytes_written = WriteAll(src: packet_data, src_len: packet_length, status, error_ptr: nullptr);
153 if (log) {
154 size_t binary_start_offset = 0;
155 if (strncmp(s1: packet_data, s2: "$vFile:pwrite:", n: strlen(s: "$vFile:pwrite:")) ==
156 0) {
157 const char *first_comma = strchr(s: packet_data, c: ',');
158 if (first_comma) {
159 const char *second_comma = strchr(s: first_comma + 1, c: ',');
160 if (second_comma)
161 binary_start_offset = second_comma - packet_data + 1;
162 }
163 }
164
165 // If logging was just enabled and we have history, then dump out what we
166 // have to the log so we get the historical context. The Dump() call that
167 // logs all of the packet will set a boolean so that we don't dump this
168 // more than once
169 if (!m_history.DidDumpToLog())
170 m_history.Dump(log);
171
172 if (binary_start_offset) {
173 StreamString strm;
174 // Print non binary data header
175 strm.Printf(format: "<%4" PRIu64 "> send packet: %.*s", (uint64_t)bytes_written,
176 (int)binary_start_offset, packet_data);
177 const uint8_t *p;
178 // Print binary data exactly as sent
179 for (p = (const uint8_t *)packet_data + binary_start_offset; *p != '#';
180 ++p)
181 strm.Printf(format: "\\x%2.2x", *p);
182 // Print the checksum
183 strm.Printf(format: "%*s", (int)3, p);
184 log->PutString(str: strm.GetString());
185 } else
186 LLDB_LOGF(log, "<%4" PRIu64 "> send packet: %.*s",
187 (uint64_t)bytes_written, (int)packet_length, packet_data);
188 }
189
190 m_history.AddPacket(src: packet.str(), src_len: packet_length,
191 type: GDBRemotePacket::ePacketTypeSend, bytes_transmitted: bytes_written);
192
193 if (bytes_written == packet_length) {
194 if (!skip_ack && GetSendAcks())
195 return GetAck();
196 else
197 return PacketResult::Success;
198 } else {
199 LLDB_LOGF(log, "error: failed to send packet: %.*s", (int)packet_length,
200 packet_data);
201 }
202 }
203 return PacketResult::ErrorSendFailed;
204}
205
206GDBRemoteCommunication::PacketResult GDBRemoteCommunication::GetAck() {
207 StringExtractorGDBRemote packet;
208 PacketResult result = WaitForPacketNoLock(response&: packet, timeout: GetPacketTimeout(), sync_on_timeout: false);
209 if (result == PacketResult::Success) {
210 if (packet.GetResponseType() ==
211 StringExtractorGDBRemote::ResponseType::eAck)
212 return PacketResult::Success;
213 else
214 return PacketResult::ErrorSendAck;
215 }
216 return result;
217}
218
219GDBRemoteCommunication::PacketResult
220GDBRemoteCommunication::ReadPacket(StringExtractorGDBRemote &response,
221 Timeout<std::micro> timeout,
222 bool sync_on_timeout) {
223 using ResponseType = StringExtractorGDBRemote::ResponseType;
224
225 Log *log = GetLog(mask: GDBRLog::Packets);
226 for (;;) {
227 PacketResult result =
228 WaitForPacketNoLock(response, timeout, sync_on_timeout);
229 if (result != PacketResult::Success ||
230 (response.GetResponseType() != ResponseType::eAck &&
231 response.GetResponseType() != ResponseType::eNack))
232 return result;
233 LLDB_LOG(log, "discarding spurious `{0}` packet", response.GetStringRef());
234 }
235}
236
237GDBRemoteCommunication::PacketResult
238GDBRemoteCommunication::WaitForPacketNoLock(StringExtractorGDBRemote &packet,
239 Timeout<std::micro> timeout,
240 bool sync_on_timeout) {
241 uint8_t buffer[8192];
242 Status error;
243
244 Log *log = GetLog(mask: GDBRLog::Packets);
245
246 // Check for a packet from our cache first without trying any reading...
247 if (CheckForPacket(src: nullptr, src_len: 0, packet) != PacketType::Invalid)
248 return PacketResult::Success;
249
250 bool timed_out = false;
251 bool disconnected = false;
252 while (IsConnected() && !timed_out) {
253 lldb::ConnectionStatus status = eConnectionStatusNoConnection;
254 size_t bytes_read = Read(dst: buffer, dst_len: sizeof(buffer), timeout, status, error_ptr: &error);
255
256 LLDB_LOGV(log,
257 "Read(buffer, sizeof(buffer), timeout = {0}, "
258 "status = {1}, error = {2}) => bytes_read = {3}",
259 timeout, Communication::ConnectionStatusAsString(status), error,
260 bytes_read);
261
262 if (bytes_read > 0) {
263 if (CheckForPacket(src: buffer, src_len: bytes_read, packet) != PacketType::Invalid)
264 return PacketResult::Success;
265 } else {
266 switch (status) {
267 case eConnectionStatusTimedOut:
268 case eConnectionStatusInterrupted:
269 if (sync_on_timeout) {
270 /// Sync the remote GDB server and make sure we get a response that
271 /// corresponds to what we send.
272 ///
273 /// Sends a "qEcho" packet and makes sure it gets the exact packet
274 /// echoed back. If the qEcho packet isn't supported, we send a qC
275 /// packet and make sure we get a valid thread ID back. We use the
276 /// "qC" packet since its response if very unique: is responds with
277 /// "QC%x" where %x is the thread ID of the current thread. This
278 /// makes the response unique enough from other packet responses to
279 /// ensure we are back on track.
280 ///
281 /// This packet is needed after we time out sending a packet so we
282 /// can ensure that we are getting the response for the packet we
283 /// are sending. There are no sequence IDs in the GDB remote
284 /// protocol (there used to be, but they are not supported anymore)
285 /// so if you timeout sending packet "abc", you might then send
286 /// packet "cde" and get the response for the previous "abc" packet.
287 /// Many responses are "OK" or "" (unsupported) or "EXX" (error) so
288 /// many responses for packets can look like responses for other
289 /// packets. So if we timeout, we need to ensure that we can get
290 /// back on track. If we can't get back on track, we must
291 /// disconnect.
292 bool sync_success = false;
293 bool got_actual_response = false;
294 // We timed out, we need to sync back up with the
295 char echo_packet[32];
296 int echo_packet_len = 0;
297 RegularExpression response_regex;
298
299 if (m_supports_qEcho == eLazyBoolYes) {
300 echo_packet_len = ::snprintf(s: echo_packet, maxlen: sizeof(echo_packet),
301 format: "qEcho:%u", ++m_echo_number);
302 std::string regex_str = "^";
303 regex_str += echo_packet;
304 regex_str += "$";
305 response_regex = RegularExpression(regex_str);
306 } else {
307 echo_packet_len =
308 ::snprintf(s: echo_packet, maxlen: sizeof(echo_packet), format: "qC");
309 response_regex =
310 RegularExpression(llvm::StringRef("^QC[0-9A-Fa-f]+$"));
311 }
312
313 PacketResult echo_packet_result =
314 SendPacketNoLock(payload: llvm::StringRef(echo_packet, echo_packet_len));
315 if (echo_packet_result == PacketResult::Success) {
316 const uint32_t max_retries = 3;
317 uint32_t successful_responses = 0;
318 for (uint32_t i = 0; i < max_retries; ++i) {
319 StringExtractorGDBRemote echo_response;
320 echo_packet_result =
321 WaitForPacketNoLock(packet&: echo_response, timeout, sync_on_timeout: false);
322 if (echo_packet_result == PacketResult::Success) {
323 ++successful_responses;
324 if (response_regex.Execute(string: echo_response.GetStringRef())) {
325 sync_success = true;
326 break;
327 } else if (successful_responses == 1) {
328 // We got something else back as the first successful
329 // response, it probably is the response to the packet we
330 // actually wanted, so copy it over if this is the first
331 // success and continue to try to get the qEcho response
332 packet = echo_response;
333 got_actual_response = true;
334 }
335 } else if (echo_packet_result == PacketResult::ErrorReplyTimeout)
336 continue; // Packet timed out, continue waiting for a response
337 else
338 break; // Something else went wrong getting the packet back, we
339 // failed and are done trying
340 }
341 }
342
343 // We weren't able to sync back up with the server, we must abort
344 // otherwise all responses might not be from the right packets...
345 if (sync_success) {
346 // We timed out, but were able to recover
347 if (got_actual_response) {
348 // We initially timed out, but we did get a response that came in
349 // before the successful reply to our qEcho packet, so lets say
350 // everything is fine...
351 return PacketResult::Success;
352 }
353 } else {
354 disconnected = true;
355 Disconnect();
356 }
357 }
358 timed_out = true;
359 break;
360 case eConnectionStatusSuccess:
361 // printf ("status = success but error = %s\n",
362 // error.AsCString("<invalid>"));
363 break;
364
365 case eConnectionStatusEndOfFile:
366 case eConnectionStatusNoConnection:
367 case eConnectionStatusLostConnection:
368 case eConnectionStatusError:
369 disconnected = true;
370 Disconnect();
371 break;
372 }
373 }
374 }
375 packet.Clear();
376 if (disconnected)
377 return PacketResult::ErrorDisconnected;
378 if (timed_out)
379 return PacketResult::ErrorReplyTimeout;
380 else
381 return PacketResult::ErrorReplyFailed;
382}
383
384bool GDBRemoteCommunication::DecompressPacket() {
385 Log *log = GetLog(mask: GDBRLog::Packets);
386
387 if (!CompressionIsEnabled())
388 return true;
389
390 size_t pkt_size = m_bytes.size();
391
392 // Smallest possible compressed packet is $N#00 - an uncompressed empty
393 // reply, most commonly indicating an unsupported packet. Anything less than
394 // 5 characters, it's definitely not a compressed packet.
395 if (pkt_size < 5)
396 return true;
397
398 if (m_bytes[0] != '$' && m_bytes[0] != '%')
399 return true;
400 if (m_bytes[1] != 'C' && m_bytes[1] != 'N')
401 return true;
402
403 size_t hash_mark_idx = m_bytes.find(c: '#');
404 if (hash_mark_idx == std::string::npos)
405 return true;
406 if (hash_mark_idx + 2 >= m_bytes.size())
407 return true;
408
409 if (!::isxdigit(m_bytes[hash_mark_idx + 1]) ||
410 !::isxdigit(m_bytes[hash_mark_idx + 2]))
411 return true;
412
413 size_t content_length =
414 pkt_size -
415 5; // not counting '$', 'C' | 'N', '#', & the two hex checksum chars
416 size_t content_start = 2; // The first character of the
417 // compressed/not-compressed text of the packet
418 size_t checksum_idx =
419 hash_mark_idx +
420 1; // The first character of the two hex checksum characters
421
422 // Normally size_of_first_packet == m_bytes.size() but m_bytes may contain
423 // multiple packets. size_of_first_packet is the size of the initial packet
424 // which we'll replace with the decompressed version of, leaving the rest of
425 // m_bytes unmodified.
426 size_t size_of_first_packet = hash_mark_idx + 3;
427
428 // Compressed packets ("$C") start with a base10 number which is the size of
429 // the uncompressed payload, then a : and then the compressed data. e.g.
430 // $C1024:<binary>#00 Update content_start and content_length to only include
431 // the <binary> part of the packet.
432
433 uint64_t decompressed_bufsize = ULONG_MAX;
434 if (m_bytes[1] == 'C') {
435 size_t i = content_start;
436 while (i < hash_mark_idx && isdigit(m_bytes[i]))
437 i++;
438 if (i < hash_mark_idx && m_bytes[i] == ':') {
439 i++;
440 content_start = i;
441 content_length = hash_mark_idx - content_start;
442 std::string bufsize_str(m_bytes.data() + 2, i - 2 - 1);
443 errno = 0;
444 decompressed_bufsize = ::strtoul(nptr: bufsize_str.c_str(), endptr: nullptr, base: 10);
445 if (errno != 0 || decompressed_bufsize == ULONG_MAX) {
446 m_bytes.erase(pos: 0, n: size_of_first_packet);
447 return false;
448 }
449 }
450 }
451
452 if (GetSendAcks()) {
453 char packet_checksum_cstr[3];
454 packet_checksum_cstr[0] = m_bytes[checksum_idx];
455 packet_checksum_cstr[1] = m_bytes[checksum_idx + 1];
456 packet_checksum_cstr[2] = '\0';
457 long packet_checksum = strtol(nptr: packet_checksum_cstr, endptr: nullptr, base: 16);
458
459 long actual_checksum = CalculcateChecksum(
460 payload: llvm::StringRef(m_bytes).substr(Start: 1, N: hash_mark_idx - 1));
461 bool success = packet_checksum == actual_checksum;
462 if (!success) {
463 LLDB_LOGF(log,
464 "error: checksum mismatch: %.*s expected 0x%2.2x, got 0x%2.2x",
465 (int)(pkt_size), m_bytes.c_str(), (uint8_t)packet_checksum,
466 (uint8_t)actual_checksum);
467 }
468 // Send the ack or nack if needed
469 if (!success) {
470 SendNack();
471 m_bytes.erase(pos: 0, n: size_of_first_packet);
472 return false;
473 } else {
474 SendAck();
475 }
476 }
477
478 if (m_bytes[1] == 'N') {
479 // This packet was not compressed -- delete the 'N' character at the start
480 // and the packet may be processed as-is.
481 m_bytes.erase(pos: 1, n: 1);
482 return true;
483 }
484
485 // Reverse the gdb-remote binary escaping that was done to the compressed
486 // text to guard characters like '$', '#', '}', etc.
487 std::vector<uint8_t> unescaped_content;
488 unescaped_content.reserve(n: content_length);
489 size_t i = content_start;
490 while (i < hash_mark_idx) {
491 if (m_bytes[i] == '}') {
492 i++;
493 unescaped_content.push_back(x: m_bytes[i] ^ 0x20);
494 } else {
495 unescaped_content.push_back(x: m_bytes[i]);
496 }
497 i++;
498 }
499
500 uint8_t *decompressed_buffer = nullptr;
501 size_t decompressed_bytes = 0;
502
503 if (decompressed_bufsize != ULONG_MAX) {
504 decompressed_buffer = (uint8_t *)malloc(size: decompressed_bufsize);
505 if (decompressed_buffer == nullptr) {
506 m_bytes.erase(pos: 0, n: size_of_first_packet);
507 return false;
508 }
509 }
510
511#if HAVE_LIBCOMPRESSION
512 if (m_compression_type == CompressionType::ZlibDeflate ||
513 m_compression_type == CompressionType::LZFSE ||
514 m_compression_type == CompressionType::LZ4 ||
515 m_compression_type == CompressionType::LZMA) {
516 compression_algorithm compression_type;
517 if (m_compression_type == CompressionType::LZFSE)
518 compression_type = COMPRESSION_LZFSE;
519 else if (m_compression_type == CompressionType::ZlibDeflate)
520 compression_type = COMPRESSION_ZLIB;
521 else if (m_compression_type == CompressionType::LZ4)
522 compression_type = COMPRESSION_LZ4_RAW;
523 else if (m_compression_type == CompressionType::LZMA)
524 compression_type = COMPRESSION_LZMA;
525
526 if (m_decompression_scratch_type != m_compression_type) {
527 if (m_decompression_scratch) {
528 free (m_decompression_scratch);
529 m_decompression_scratch = nullptr;
530 }
531 size_t scratchbuf_size = 0;
532 if (m_compression_type == CompressionType::LZFSE)
533 scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_LZFSE);
534 else if (m_compression_type == CompressionType::LZ4)
535 scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_LZ4_RAW);
536 else if (m_compression_type == CompressionType::ZlibDeflate)
537 scratchbuf_size = compression_decode_scratch_buffer_size (COMPRESSION_ZLIB);
538 else if (m_compression_type == CompressionType::LZMA)
539 scratchbuf_size =
540 compression_decode_scratch_buffer_size(COMPRESSION_LZMA);
541 if (scratchbuf_size > 0) {
542 m_decompression_scratch = (void*) malloc (scratchbuf_size);
543 m_decompression_scratch_type = m_compression_type;
544 }
545 }
546
547 if (decompressed_bufsize != ULONG_MAX && decompressed_buffer != nullptr) {
548 decompressed_bytes = compression_decode_buffer(
549 decompressed_buffer, decompressed_bufsize,
550 (uint8_t *)unescaped_content.data(), unescaped_content.size(),
551 m_decompression_scratch, compression_type);
552 }
553 }
554#endif
555
556#if LLVM_ENABLE_ZLIB
557 if (decompressed_bytes == 0 && decompressed_bufsize != ULONG_MAX &&
558 decompressed_buffer != nullptr &&
559 m_compression_type == CompressionType::ZlibDeflate) {
560 z_stream stream;
561 memset(s: &stream, c: 0, n: sizeof(z_stream));
562 stream.next_in = (Bytef *)unescaped_content.data();
563 stream.avail_in = (uInt)unescaped_content.size();
564 stream.total_in = 0;
565 stream.next_out = (Bytef *)decompressed_buffer;
566 stream.avail_out = decompressed_bufsize;
567 stream.total_out = 0;
568 stream.zalloc = Z_NULL;
569 stream.zfree = Z_NULL;
570 stream.opaque = Z_NULL;
571
572 if (inflateInit2(&stream, -15) == Z_OK) {
573 int status = inflate(strm: &stream, Z_NO_FLUSH);
574 inflateEnd(strm: &stream);
575 if (status == Z_STREAM_END) {
576 decompressed_bytes = stream.total_out;
577 }
578 }
579 }
580#endif
581
582 if (decompressed_bytes == 0 || decompressed_buffer == nullptr) {
583 if (decompressed_buffer)
584 free(ptr: decompressed_buffer);
585 m_bytes.erase(pos: 0, n: size_of_first_packet);
586 return false;
587 }
588
589 std::string new_packet;
590 new_packet.reserve(res: decompressed_bytes + 6);
591 new_packet.push_back(c: m_bytes[0]);
592 new_packet.append(s: (const char *)decompressed_buffer, n: decompressed_bytes);
593 new_packet.push_back(c: '#');
594 if (GetSendAcks()) {
595 uint8_t decompressed_checksum = CalculcateChecksum(
596 payload: llvm::StringRef((const char *)decompressed_buffer, decompressed_bytes));
597 char decompressed_checksum_str[3];
598 snprintf(s: decompressed_checksum_str, maxlen: 3, format: "%02x", decompressed_checksum);
599 new_packet.append(s: decompressed_checksum_str);
600 } else {
601 new_packet.push_back(c: '0');
602 new_packet.push_back(c: '0');
603 }
604
605 m_bytes.replace(pos: 0, n1: size_of_first_packet, s: new_packet.data(),
606 n2: new_packet.size());
607
608 free(ptr: decompressed_buffer);
609 return true;
610}
611
612GDBRemoteCommunication::PacketType
613GDBRemoteCommunication::CheckForPacket(const uint8_t *src, size_t src_len,
614 StringExtractorGDBRemote &packet) {
615 // Put the packet data into the buffer in a thread safe fashion
616 std::lock_guard<std::recursive_mutex> guard(m_bytes_mutex);
617
618 Log *log = GetLog(mask: GDBRLog::Packets);
619
620 if (src && src_len > 0) {
621 if (log && log->GetVerbose()) {
622 StreamString s;
623 LLDB_LOGF(log, "GDBRemoteCommunication::%s adding %u bytes: %.*s",
624 __FUNCTION__, (uint32_t)src_len, (uint32_t)src_len, src);
625 }
626 m_bytes.append(s: (const char *)src, n: src_len);
627 }
628
629 bool isNotifyPacket = false;
630
631 // Parse up the packets into gdb remote packets
632 if (!m_bytes.empty()) {
633 // end_idx must be one past the last valid packet byte. Start it off with
634 // an invalid value that is the same as the current index.
635 size_t content_start = 0;
636 size_t content_length = 0;
637 size_t total_length = 0;
638 size_t checksum_idx = std::string::npos;
639
640 // Size of packet before it is decompressed, for logging purposes
641 size_t original_packet_size = m_bytes.size();
642 if (CompressionIsEnabled()) {
643 if (!DecompressPacket()) {
644 packet.Clear();
645 return GDBRemoteCommunication::PacketType::Standard;
646 }
647 }
648
649 switch (m_bytes[0]) {
650 case '+': // Look for ack
651 case '-': // Look for cancel
652 case '\x03': // ^C to halt target
653 content_length = total_length = 1; // The command is one byte long...
654 break;
655
656 case '%': // Async notify packet
657 isNotifyPacket = true;
658 [[fallthrough]];
659
660 case '$':
661 // Look for a standard gdb packet?
662 {
663 size_t hash_pos = m_bytes.find(c: '#');
664 if (hash_pos != std::string::npos) {
665 if (hash_pos + 2 < m_bytes.size()) {
666 checksum_idx = hash_pos + 1;
667 // Skip the dollar sign
668 content_start = 1;
669 // Don't include the # in the content or the $ in the content
670 // length
671 content_length = hash_pos - 1;
672
673 total_length =
674 hash_pos + 3; // Skip the # and the two hex checksum bytes
675 } else {
676 // Checksum bytes aren't all here yet
677 content_length = std::string::npos;
678 }
679 }
680 }
681 break;
682
683 default: {
684 // We have an unexpected byte and we need to flush all bad data that is
685 // in m_bytes, so we need to find the first byte that is a '+' (ACK), '-'
686 // (NACK), \x03 (CTRL+C interrupt), or '$' character (start of packet
687 // header) or of course, the end of the data in m_bytes...
688 const size_t bytes_len = m_bytes.size();
689 bool done = false;
690 uint32_t idx;
691 for (idx = 1; !done && idx < bytes_len; ++idx) {
692 switch (m_bytes[idx]) {
693 case '+':
694 case '-':
695 case '\x03':
696 case '%':
697 case '$':
698 done = true;
699 break;
700
701 default:
702 break;
703 }
704 }
705 LLDB_LOGF(log, "GDBRemoteCommunication::%s tossing %u junk bytes: '%.*s'",
706 __FUNCTION__, idx - 1, idx - 1, m_bytes.c_str());
707 m_bytes.erase(pos: 0, n: idx - 1);
708 } break;
709 }
710
711 if (content_length == std::string::npos) {
712 packet.Clear();
713 return GDBRemoteCommunication::PacketType::Invalid;
714 } else if (total_length > 0) {
715
716 // We have a valid packet...
717 assert(content_length <= m_bytes.size());
718 assert(total_length <= m_bytes.size());
719 assert(content_length <= total_length);
720 size_t content_end = content_start + content_length;
721
722 bool success = true;
723 if (log) {
724 // If logging was just enabled and we have history, then dump out what
725 // we have to the log so we get the historical context. The Dump() call
726 // that logs all of the packet will set a boolean so that we don't dump
727 // this more than once
728 if (!m_history.DidDumpToLog())
729 m_history.Dump(log);
730
731 bool binary = false;
732 // Only detect binary for packets that start with a '$' and have a
733 // '#CC' checksum
734 if (m_bytes[0] == '$' && total_length > 4) {
735 for (size_t i = 0; !binary && i < total_length; ++i) {
736 unsigned char c = m_bytes[i];
737 if (!llvm::isPrint(C: c) && !llvm::isSpace(C: c)) {
738 binary = true;
739 }
740 }
741 }
742 if (binary) {
743 StreamString strm;
744 // Packet header...
745 if (CompressionIsEnabled())
746 strm.Printf(format: "<%4" PRIu64 ":%" PRIu64 "> read packet: %c",
747 (uint64_t)original_packet_size, (uint64_t)total_length,
748 m_bytes[0]);
749 else
750 strm.Printf(format: "<%4" PRIu64 "> read packet: %c",
751 (uint64_t)total_length, m_bytes[0]);
752 for (size_t i = content_start; i < content_end; ++i) {
753 // Remove binary escaped bytes when displaying the packet...
754 const char ch = m_bytes[i];
755 if (ch == 0x7d) {
756 // 0x7d is the escape character. The next character is to be
757 // XOR'd with 0x20.
758 const char escapee = m_bytes[++i] ^ 0x20;
759 strm.Printf(format: "%2.2x", escapee);
760 } else {
761 strm.Printf(format: "%2.2x", (uint8_t)ch);
762 }
763 }
764 // Packet footer...
765 strm.Printf(format: "%c%c%c", m_bytes[total_length - 3],
766 m_bytes[total_length - 2], m_bytes[total_length - 1]);
767 log->PutString(str: strm.GetString());
768 } else {
769 if (CompressionIsEnabled())
770 LLDB_LOGF(log, "<%4" PRIu64 ":%" PRIu64 "> read packet: %.*s",
771 (uint64_t)original_packet_size, (uint64_t)total_length,
772 (int)(total_length), m_bytes.c_str());
773 else
774 LLDB_LOGF(log, "<%4" PRIu64 "> read packet: %.*s",
775 (uint64_t)total_length, (int)(total_length),
776 m_bytes.c_str());
777 }
778 }
779
780 m_history.AddPacket(src: m_bytes, src_len: total_length,
781 type: GDBRemotePacket::ePacketTypeRecv, bytes_transmitted: total_length);
782
783 // Copy the packet from m_bytes to packet_str expanding the run-length
784 // encoding in the process.
785 auto maybe_packet_str =
786 ExpandRLE(m_bytes.substr(pos: content_start, n: content_end - content_start));
787 if (!maybe_packet_str) {
788 m_bytes.erase(pos: 0, n: total_length);
789 packet.Clear();
790 return GDBRemoteCommunication::PacketType::Invalid;
791 }
792 packet = StringExtractorGDBRemote(*maybe_packet_str);
793
794 if (m_bytes[0] == '$' || m_bytes[0] == '%') {
795 assert(checksum_idx < m_bytes.size());
796 if (::isxdigit(m_bytes[checksum_idx + 0]) ||
797 ::isxdigit(m_bytes[checksum_idx + 1])) {
798 if (GetSendAcks()) {
799 const char *packet_checksum_cstr = &m_bytes[checksum_idx];
800 char packet_checksum = strtol(nptr: packet_checksum_cstr, endptr: nullptr, base: 16);
801 char actual_checksum = CalculcateChecksum(
802 payload: llvm::StringRef(m_bytes).slice(Start: content_start, End: content_end));
803 success = packet_checksum == actual_checksum;
804 if (!success) {
805 LLDB_LOGF(log,
806 "error: checksum mismatch: %.*s expected 0x%2.2x, "
807 "got 0x%2.2x",
808 (int)(total_length), m_bytes.c_str(),
809 (uint8_t)packet_checksum, (uint8_t)actual_checksum);
810 }
811 // Send the ack or nack if needed
812 if (!success)
813 SendNack();
814 else
815 SendAck();
816 }
817 } else {
818 success = false;
819 LLDB_LOGF(log, "error: invalid checksum in packet: '%s'\n",
820 m_bytes.c_str());
821 }
822 }
823
824 m_bytes.erase(pos: 0, n: total_length);
825 packet.SetFilePos(0);
826
827 if (isNotifyPacket)
828 return GDBRemoteCommunication::PacketType::Notify;
829 else
830 return GDBRemoteCommunication::PacketType::Standard;
831 }
832 }
833 packet.Clear();
834 return GDBRemoteCommunication::PacketType::Invalid;
835}
836
837FileSpec GDBRemoteCommunication::GetDebugserverPath(Platform *platform) {
838 Log *log = GetLog(mask: GDBRLog::Process);
839 // If we locate debugserver, keep that located version around
840 static FileSpec g_debugserver_file_spec;
841 FileSpec debugserver_file_spec;
842
843 Environment host_env = Host::GetEnvironment();
844
845 // Always check to see if we have an environment override for the path to the
846 // debugserver to use and use it if we do.
847 std::string env_debugserver_path = host_env.lookup(Key: "LLDB_DEBUGSERVER_PATH");
848 if (!env_debugserver_path.empty()) {
849 debugserver_file_spec.SetFile(path: env_debugserver_path,
850 style: FileSpec::Style::native);
851 LLDB_LOGF(log,
852 "GDBRemoteCommunication::%s() gdb-remote stub exe path set "
853 "from environment variable: %s",
854 __FUNCTION__, env_debugserver_path.c_str());
855 } else
856 debugserver_file_spec = g_debugserver_file_spec;
857 bool debugserver_exists =
858 FileSystem::Instance().Exists(file_spec: debugserver_file_spec);
859 if (!debugserver_exists) {
860 // The debugserver binary is in the LLDB.framework/Resources directory.
861 debugserver_file_spec = HostInfo::GetSupportExeDir();
862 if (debugserver_file_spec) {
863 debugserver_file_spec.AppendPathComponent(DEBUGSERVER_BASENAME);
864 debugserver_exists = FileSystem::Instance().Exists(file_spec: debugserver_file_spec);
865 if (debugserver_exists) {
866 LLDB_LOGF(log,
867 "GDBRemoteCommunication::%s() found gdb-remote stub exe '%s'",
868 __FUNCTION__, debugserver_file_spec.GetPath().c_str());
869
870 g_debugserver_file_spec = debugserver_file_spec;
871 } else {
872 if (platform)
873 debugserver_file_spec =
874 platform->LocateExecutable(DEBUGSERVER_BASENAME);
875 else
876 debugserver_file_spec.Clear();
877 if (debugserver_file_spec) {
878 // Platform::LocateExecutable() wouldn't return a path if it doesn't
879 // exist
880 debugserver_exists = true;
881 } else {
882 LLDB_LOGF(log,
883 "GDBRemoteCommunication::%s() could not find "
884 "gdb-remote stub exe '%s'",
885 __FUNCTION__, debugserver_file_spec.GetPath().c_str());
886 }
887 // Don't cache the platform specific GDB server binary as it could
888 // change from platform to platform
889 g_debugserver_file_spec.Clear();
890 }
891 }
892 }
893 return debugserver_file_spec;
894}
895
896Status GDBRemoteCommunication::StartDebugserverProcess(
897 const char *url, Platform *platform, ProcessLaunchInfo &launch_info,
898 uint16_t *port, const Args *inferior_args, shared_fd_t pass_comm_fd) {
899 Log *log = GetLog(mask: GDBRLog::Process);
900 LLDB_LOG(log, "Starting debug server: url={0}, port={1}",
901 url ? url : "<empty>", port ? *port : uint16_t(0));
902
903 FileSpec debugserver_file_spec = GetDebugserverPath(platform);
904 if (!debugserver_file_spec)
905 return Status::FromErrorString(str: "unable to locate " DEBUGSERVER_BASENAME);
906
907 launch_info.SetExecutableFile(exe_file: debugserver_file_spec,
908 /*add_exe_file_as_first_arg=*/true);
909
910 Args &debugserver_args = launch_info.GetArguments();
911
912#if !defined(__APPLE__)
913 // First argument to lldb-server must be mode in which to run.
914 debugserver_args.AppendArgument(arg_str: llvm::StringRef("gdbserver"));
915#endif
916
917 // If a url is supplied then use it
918 if (url && url[0])
919 debugserver_args.AppendArgument(arg_str: llvm::StringRef(url));
920
921 if (pass_comm_fd != SharedSocket::kInvalidFD) {
922 StreamString fd_arg;
923 fd_arg.Printf(format: "--fd=%" PRIi64, (int64_t)pass_comm_fd);
924 debugserver_args.AppendArgument(arg_str: fd_arg.GetString());
925 // Send "pass_comm_fd" down to the inferior so it can use it to
926 // communicate back with this process. Ignored on Windows.
927 launch_info.AppendDuplicateFileAction(fd: (int64_t)pass_comm_fd,
928 dup_fd: (int64_t)pass_comm_fd);
929 }
930
931 // use native registers, not the GDB registers
932 debugserver_args.AppendArgument(arg_str: llvm::StringRef("--native-regs"));
933
934 if (launch_info.GetLaunchInSeparateProcessGroup())
935 debugserver_args.AppendArgument(arg_str: llvm::StringRef("--setsid"));
936
937 llvm::SmallString<128> named_pipe_path;
938 // socket_pipe is used by debug server to communicate back either
939 // TCP port or domain socket name which it listens on.
940 // The second purpose of the pipe to serve as a synchronization point -
941 // once data is written to the pipe, debug server is up and running.
942 Pipe socket_pipe;
943
944 std::unique_ptr<TCPSocket> sock_up;
945
946 // port is null when debug server should listen on domain socket - we're
947 // not interested in port value but rather waiting for debug server to
948 // become available.
949 if (pass_comm_fd == SharedSocket::kInvalidFD) {
950 if (url) {
951// Create a temporary file to get the stdout/stderr and redirect the output of
952// the command into this file. We will later read this file if all goes well
953// and fill the data into "command_output_ptr"
954#if defined(__APPLE__)
955 // Binding to port zero, we need to figure out what port it ends up
956 // using using a named pipe...
957 Status error = socket_pipe.CreateWithUniqueName("debugserver-named-pipe",
958 false, named_pipe_path);
959 if (error.Fail()) {
960 LLDB_LOG(log, "named pipe creation failed: {0}", error);
961 return error;
962 }
963 debugserver_args.AppendArgument(llvm::StringRef("--named-pipe"));
964 debugserver_args.AppendArgument(named_pipe_path);
965#else
966 // Binding to port zero, we need to figure out what port it ends up
967 // using using an unnamed pipe...
968 Status error = socket_pipe.CreateNew(child_process_inherit: true);
969 if (error.Fail()) {
970 LLDB_LOG(log, "unnamed pipe creation failed: {0}", error);
971 return error;
972 }
973 pipe_t write = socket_pipe.GetWritePipe();
974 debugserver_args.AppendArgument(arg_str: llvm::StringRef("--pipe"));
975 debugserver_args.AppendArgument(arg_str: llvm::to_string(Value: write));
976 launch_info.AppendCloseFileAction(fd: socket_pipe.GetReadFileDescriptor());
977#endif
978 } else {
979 // No host and port given, so lets listen on our end and make the
980 // debugserver connect to us..
981 if (llvm::Expected<std::unique_ptr<TCPSocket>> expected_sock =
982 Socket::TcpListen(host_and_port: "127.0.0.1:0"))
983 sock_up = std::move(*expected_sock);
984 else
985 return Status::FromError(error: expected_sock.takeError());
986
987 uint16_t port_ = sock_up->GetLocalPortNumber();
988 // Send the host and port down that debugserver and specify an option
989 // so that it connects back to the port we are listening to in this
990 // process
991 debugserver_args.AppendArgument(arg_str: llvm::StringRef("--reverse-connect"));
992 debugserver_args.AppendArgument(
993 arg_str: llvm::formatv(Fmt: "127.0.0.1:{0}", Vals&: port_).str());
994 if (port)
995 *port = port_;
996 }
997 }
998
999 Environment host_env = Host::GetEnvironment();
1000 std::string env_debugserver_log_file =
1001 host_env.lookup(Key: "LLDB_DEBUGSERVER_LOG_FILE");
1002 if (!env_debugserver_log_file.empty()) {
1003 debugserver_args.AppendArgument(
1004 arg_str: llvm::formatv(Fmt: "--log-file={0}", Vals&: env_debugserver_log_file).str());
1005 }
1006
1007#if defined(__APPLE__)
1008 const char *env_debugserver_log_flags = getenv("LLDB_DEBUGSERVER_LOG_FLAGS");
1009 if (env_debugserver_log_flags) {
1010 debugserver_args.AppendArgument(
1011 llvm::formatv("--log-flags={0}", env_debugserver_log_flags).str());
1012 }
1013#else
1014 std::string env_debugserver_log_channels =
1015 host_env.lookup(Key: "LLDB_SERVER_LOG_CHANNELS");
1016 if (!env_debugserver_log_channels.empty()) {
1017 debugserver_args.AppendArgument(
1018 arg_str: llvm::formatv(Fmt: "--log-channels={0}", Vals&: env_debugserver_log_channels)
1019 .str());
1020 }
1021#endif
1022
1023 // Add additional args, starting with LLDB_DEBUGSERVER_EXTRA_ARG_1 until an
1024 // env var doesn't come back.
1025 uint32_t env_var_index = 1;
1026 bool has_env_var;
1027 do {
1028 char env_var_name[64];
1029 snprintf(s: env_var_name, maxlen: sizeof(env_var_name),
1030 format: "LLDB_DEBUGSERVER_EXTRA_ARG_%" PRIu32, env_var_index++);
1031 std::string extra_arg = host_env.lookup(Key: env_var_name);
1032 has_env_var = !extra_arg.empty();
1033
1034 if (has_env_var) {
1035 debugserver_args.AppendArgument(arg_str: llvm::StringRef(extra_arg));
1036 LLDB_LOGF(log,
1037 "GDBRemoteCommunication::%s adding env var %s contents "
1038 "to stub command line (%s)",
1039 __FUNCTION__, env_var_name, extra_arg.c_str());
1040 }
1041 } while (has_env_var);
1042
1043 if (inferior_args && inferior_args->GetArgumentCount() > 0) {
1044 debugserver_args.AppendArgument(arg_str: llvm::StringRef("--"));
1045 debugserver_args.AppendArguments(rhs: *inferior_args);
1046 }
1047
1048 // Copy the current environment to the gdbserver/debugserver instance
1049 launch_info.GetEnvironment() = host_env;
1050
1051 // Close STDIN, STDOUT and STDERR.
1052 launch_info.AppendCloseFileAction(STDIN_FILENO);
1053 launch_info.AppendCloseFileAction(STDOUT_FILENO);
1054 launch_info.AppendCloseFileAction(STDERR_FILENO);
1055
1056 // Redirect STDIN, STDOUT and STDERR to "/dev/null".
1057 launch_info.AppendSuppressFileAction(STDIN_FILENO, read: true, write: false);
1058 launch_info.AppendSuppressFileAction(STDOUT_FILENO, read: false, write: true);
1059 launch_info.AppendSuppressFileAction(STDERR_FILENO, read: false, write: true);
1060
1061 if (log) {
1062 StreamString string_stream;
1063 Platform *const platform = nullptr;
1064 launch_info.Dump(s&: string_stream, platform);
1065 LLDB_LOG(log, "launch info for gdb-remote stub:\n{0}",
1066 string_stream.GetData());
1067 }
1068 if (Status error = Host::LaunchProcess(launch_info); error.Fail()) {
1069 LLDB_LOG(log, "launch failed: {0}", error);
1070 return error;
1071 }
1072
1073 if (pass_comm_fd != SharedSocket::kInvalidFD)
1074 return Status();
1075
1076 Status error;
1077 if (named_pipe_path.size() > 0) {
1078 error = socket_pipe.OpenAsReader(name: named_pipe_path, child_process_inherit: false);
1079 if (error.Fail()) {
1080 LLDB_LOG(log, "failed to open named pipe {0} for reading: {1}",
1081 named_pipe_path, error);
1082 }
1083 }
1084
1085 if (socket_pipe.CanWrite())
1086 socket_pipe.CloseWriteFileDescriptor();
1087 if (socket_pipe.CanRead()) {
1088 // Read port from pipe with 10 second timeout.
1089 std::string port_str;
1090 while (error.Success()) {
1091 char buf[10];
1092 if (llvm::Expected<size_t> num_bytes =
1093 socket_pipe.Read(buf, size: std::size(buf), timeout: std::chrono::seconds(10))) {
1094 if (*num_bytes == 0)
1095 break;
1096 port_str.append(s: buf, n: *num_bytes);
1097 } else {
1098 error = Status::FromError(error: num_bytes.takeError());
1099 }
1100 }
1101 if (error.Success() && (port != nullptr)) {
1102 // NB: Deliberately using .c_str() to stop at embedded '\0's
1103 llvm::StringRef port_ref = port_str.c_str();
1104 uint16_t child_port = 0;
1105 // FIXME: improve error handling
1106 llvm::to_integer(S: port_ref, Num&: child_port);
1107 if (*port == 0 || *port == child_port) {
1108 *port = child_port;
1109 LLDB_LOG(log, "debugserver listens on port {0}", *port);
1110 } else {
1111 LLDB_LOG(log,
1112 "debugserver listening on port {0} but requested port was {1}",
1113 child_port, (*port));
1114 }
1115 } else {
1116 LLDB_LOG(log, "failed to read a port value from pipe {0}: {1}",
1117 named_pipe_path, error);
1118 }
1119 socket_pipe.Close();
1120 }
1121
1122 if (named_pipe_path.size() > 0) {
1123 if (Status err = socket_pipe.Delete(name: named_pipe_path); err.Fail())
1124 LLDB_LOG(log, "failed to delete pipe {0}: {1}", named_pipe_path, err);
1125 }
1126
1127 if (error.Success() && sock_up) {
1128 Socket *accepted_socket = nullptr;
1129 error = sock_up->Accept(/*timeout=*/std::nullopt, socket&: accepted_socket);
1130 if (accepted_socket) {
1131 SetConnection(
1132 std::make_unique<ConnectionFileDescriptor>(args&: accepted_socket));
1133 }
1134 }
1135
1136 return error;
1137}
1138
1139void GDBRemoteCommunication::DumpHistory(Stream &strm) { m_history.Dump(strm); }
1140
1141llvm::Error
1142GDBRemoteCommunication::ConnectLocally(GDBRemoteCommunication &client,
1143 GDBRemoteCommunication &server) {
1144 const int backlog = 5;
1145 TCPSocket listen_socket(true);
1146 if (llvm::Error error =
1147 listen_socket.Listen(name: "localhost:0", backlog).ToError())
1148 return error;
1149
1150 llvm::SmallString<32> remote_addr;
1151 llvm::raw_svector_ostream(remote_addr)
1152 << "connect://localhost:" << listen_socket.GetLocalPortNumber();
1153
1154 std::unique_ptr<ConnectionFileDescriptor> conn_up(
1155 new ConnectionFileDescriptor());
1156 Status status;
1157 if (conn_up->Connect(url: remote_addr, error_ptr: &status) != lldb::eConnectionStatusSuccess)
1158 return llvm::createStringError(EC: llvm::inconvertibleErrorCode(),
1159 Fmt: "Unable to connect: %s", Vals: status.AsCString());
1160
1161 // The connection was already established above, so a short timeout is
1162 // sufficient.
1163 Socket *accept_socket = nullptr;
1164 if (Status accept_status =
1165 listen_socket.Accept(timeout: std::chrono::seconds(1), socket&: accept_socket);
1166 accept_status.Fail())
1167 return accept_status.takeError();
1168
1169 client.SetConnection(std::move(conn_up));
1170 server.SetConnection(
1171 std::make_unique<ConnectionFileDescriptor>(args&: accept_socket));
1172 return llvm::Error::success();
1173}
1174
1175GDBRemoteCommunication::ScopedTimeout::ScopedTimeout(
1176 GDBRemoteCommunication &gdb_comm, std::chrono::seconds timeout)
1177 : m_gdb_comm(gdb_comm), m_saved_timeout(0), m_timeout_modified(false) {
1178 auto curr_timeout = gdb_comm.GetPacketTimeout();
1179 // Only update the timeout if the timeout is greater than the current
1180 // timeout. If the current timeout is larger, then just use that.
1181 if (curr_timeout < timeout) {
1182 m_timeout_modified = true;
1183 m_saved_timeout = m_gdb_comm.SetPacketTimeout(timeout);
1184 }
1185}
1186
1187GDBRemoteCommunication::ScopedTimeout::~ScopedTimeout() {
1188 // Only restore the timeout if we set it in the constructor.
1189 if (m_timeout_modified)
1190 m_gdb_comm.SetPacketTimeout(m_saved_timeout);
1191}
1192
1193void llvm::format_provider<GDBRemoteCommunication::PacketResult>::format(
1194 const GDBRemoteCommunication::PacketResult &result, raw_ostream &Stream,
1195 StringRef Style) {
1196 using PacketResult = GDBRemoteCommunication::PacketResult;
1197
1198 switch (result) {
1199 case PacketResult::Success:
1200 Stream << "Success";
1201 break;
1202 case PacketResult::ErrorSendFailed:
1203 Stream << "ErrorSendFailed";
1204 break;
1205 case PacketResult::ErrorSendAck:
1206 Stream << "ErrorSendAck";
1207 break;
1208 case PacketResult::ErrorReplyFailed:
1209 Stream << "ErrorReplyFailed";
1210 break;
1211 case PacketResult::ErrorReplyTimeout:
1212 Stream << "ErrorReplyTimeout";
1213 break;
1214 case PacketResult::ErrorReplyInvalid:
1215 Stream << "ErrorReplyInvalid";
1216 break;
1217 case PacketResult::ErrorReplyAck:
1218 Stream << "ErrorReplyAck";
1219 break;
1220 case PacketResult::ErrorDisconnected:
1221 Stream << "ErrorDisconnected";
1222 break;
1223 case PacketResult::ErrorNoSequenceLock:
1224 Stream << "ErrorNoSequenceLock";
1225 break;
1226 }
1227}
1228
1229std::optional<std::string>
1230GDBRemoteCommunication::ExpandRLE(std::string packet) {
1231 // Reserve enough byte for the most common case (no RLE used).
1232 std::string decoded;
1233 decoded.reserve(res: packet.size());
1234 for (std::string::const_iterator c = packet.begin(); c != packet.end(); ++c) {
1235 if (*c == '*') {
1236 if (decoded.empty())
1237 return std::nullopt;
1238 // '*' indicates RLE. Next character will give us the repeat count and
1239 // previous character is what is to be repeated.
1240 char char_to_repeat = decoded.back();
1241 // Number of time the previous character is repeated.
1242 if (++c == packet.end())
1243 return std::nullopt;
1244 int repeat_count = *c + 3 - ' ';
1245 // We have the char_to_repeat and repeat_count. Now push it in the
1246 // packet.
1247 for (int i = 0; i < repeat_count; ++i)
1248 decoded.push_back(c: char_to_repeat);
1249 } else if (*c == 0x7d) {
1250 // 0x7d is the escape character. The next character is to be XOR'd with
1251 // 0x20.
1252 if (++c == packet.end())
1253 return std::nullopt;
1254 char escapee = *c ^ 0x20;
1255 decoded.push_back(c: escapee);
1256 } else {
1257 decoded.push_back(c: *c);
1258 }
1259 }
1260 return decoded;
1261}
1262

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