1//===-- lldb-gdbserver.cpp --------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include <cerrno>
10#include <cstdint>
11#include <cstdio>
12#include <cstdlib>
13#include <cstring>
14
15#ifndef _WIN32
16#include <csignal>
17#include <unistd.h>
18#endif
19
20#include "LLDBServerUtilities.h"
21#include "Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h"
22#include "Plugins/Process/gdb-remote/ProcessGDBRemoteLog.h"
23#include "lldb/Host/Config.h"
24#include "lldb/Host/ConnectionFileDescriptor.h"
25#include "lldb/Host/FileSystem.h"
26#include "lldb/Host/Pipe.h"
27#include "lldb/Host/common/NativeProcessProtocol.h"
28#include "lldb/Host/common/TCPSocket.h"
29#include "lldb/Target/Process.h"
30#include "lldb/Utility/LLDBLog.h"
31#include "lldb/Utility/Status.h"
32#include "llvm/ADT/StringRef.h"
33#include "llvm/Option/ArgList.h"
34#include "llvm/Option/OptTable.h"
35#include "llvm/Option/Option.h"
36#include "llvm/Support/Errno.h"
37#include "llvm/Support/Error.h"
38#include "llvm/Support/WithColor.h"
39
40#if defined(__linux__)
41#include "Plugins/Process/Linux/NativeProcessLinux.h"
42#elif defined(__FreeBSD__)
43#include "Plugins/Process/FreeBSD/NativeProcessFreeBSD.h"
44#elif defined(__NetBSD__)
45#include "Plugins/Process/NetBSD/NativeProcessNetBSD.h"
46#elif defined(_WIN32)
47#include "Plugins/Process/Windows/Common/NativeProcessWindows.h"
48#endif
49
50#ifndef LLGS_PROGRAM_NAME
51#define LLGS_PROGRAM_NAME "lldb-server"
52#endif
53
54#ifndef LLGS_VERSION_STR
55#define LLGS_VERSION_STR "local_build"
56#endif
57
58using namespace llvm;
59using namespace lldb;
60using namespace lldb_private;
61using namespace lldb_private::lldb_server;
62using namespace lldb_private::process_gdb_remote;
63
64namespace {
65#if defined(__linux__)
66typedef process_linux::NativeProcessLinux::Manager NativeProcessManager;
67#elif defined(__FreeBSD__)
68typedef process_freebsd::NativeProcessFreeBSD::Manager NativeProcessManager;
69#elif defined(__NetBSD__)
70typedef process_netbsd::NativeProcessNetBSD::Manager NativeProcessManager;
71#elif defined(_WIN32)
72typedef NativeProcessWindows::Manager NativeProcessManager;
73#else
74// Dummy implementation to make sure the code compiles
75class NativeProcessManager : public NativeProcessProtocol::Manager {
76public:
77 NativeProcessManager(MainLoop &mainloop)
78 : NativeProcessProtocol::Manager(mainloop) {}
79
80 llvm::Expected<std::unique_ptr<NativeProcessProtocol>>
81 Launch(ProcessLaunchInfo &launch_info,
82 NativeProcessProtocol::NativeDelegate &native_delegate) override {
83 llvm_unreachable("Not implemented");
84 }
85 llvm::Expected<std::unique_ptr<NativeProcessProtocol>>
86 Attach(lldb::pid_t pid,
87 NativeProcessProtocol::NativeDelegate &native_delegate) override {
88 llvm_unreachable("Not implemented");
89 }
90};
91#endif
92}
93
94#ifndef _WIN32
95// Watch for signals
96static int g_sighup_received_count = 0;
97
98static void sighup_handler(MainLoopBase &mainloop) {
99 ++g_sighup_received_count;
100
101 Log *log = GetLog(mask: LLDBLog::Process);
102 LLDB_LOGF(log, "lldb-server:%s swallowing SIGHUP (receive count=%d)",
103 __FUNCTION__, g_sighup_received_count);
104
105 if (g_sighup_received_count >= 2)
106 mainloop.RequestTermination();
107}
108#endif // #ifndef _WIN32
109
110void handle_attach_to_pid(GDBRemoteCommunicationServerLLGS &gdb_server,
111 lldb::pid_t pid) {
112 Status error = gdb_server.AttachToProcess(pid);
113 if (error.Fail()) {
114 fprintf(stderr, format: "error: failed to attach to pid %" PRIu64 ": %s\n", pid,
115 error.AsCString());
116 exit(status: 1);
117 }
118}
119
120void handle_attach_to_process_name(GDBRemoteCommunicationServerLLGS &gdb_server,
121 const std::string &process_name) {
122 // FIXME implement.
123}
124
125void handle_attach(GDBRemoteCommunicationServerLLGS &gdb_server,
126 const std::string &attach_target) {
127 assert(!attach_target.empty() && "attach_target cannot be empty");
128
129 // First check if the attach_target is convertible to a long. If so, we'll use
130 // it as a pid.
131 char *end_p = nullptr;
132 const long int pid = strtol(nptr: attach_target.c_str(), endptr: &end_p, base: 10);
133
134 // We'll call it a match if the entire argument is consumed.
135 if (end_p &&
136 static_cast<size_t>(end_p - attach_target.c_str()) ==
137 attach_target.size())
138 handle_attach_to_pid(gdb_server, pid: static_cast<lldb::pid_t>(pid));
139 else
140 handle_attach_to_process_name(gdb_server, process_name: attach_target);
141}
142
143void handle_launch(GDBRemoteCommunicationServerLLGS &gdb_server,
144 llvm::ArrayRef<llvm::StringRef> Arguments) {
145 ProcessLaunchInfo info;
146 info.GetFlags().Set(eLaunchFlagStopAtEntry | eLaunchFlagDebug |
147 eLaunchFlagDisableASLR);
148 info.SetArguments(args: Args(Arguments), first_arg_is_executable: true);
149
150 llvm::SmallString<64> cwd;
151 if (std::error_code ec = llvm::sys::fs::current_path(result&: cwd)) {
152 llvm::errs() << "Error getting current directory: " << ec.message() << "\n";
153 exit(status: 1);
154 }
155 FileSpec cwd_spec(cwd);
156 FileSystem::Instance().Resolve(file_spec&: cwd_spec);
157 info.SetWorkingDirectory(cwd_spec);
158 info.GetEnvironment() = Host::GetEnvironment();
159
160 gdb_server.SetLaunchInfo(info);
161
162 Status error = gdb_server.LaunchProcess();
163 if (error.Fail()) {
164 llvm::errs() << llvm::formatv(Fmt: "error: failed to launch '{0}': {1}\n",
165 Vals: Arguments[0], Vals&: error);
166 exit(status: 1);
167 }
168}
169
170static Status writeSocketIdToPipe(Pipe &port_pipe,
171 const std::string &socket_id) {
172 // NB: Include the nul character at the end.
173 llvm::StringRef buf(socket_id.data(), socket_id.size() + 1);
174 while (!buf.empty()) {
175 if (llvm::Expected<size_t> written =
176 port_pipe.Write(buf: buf.data(), size: buf.size()))
177 buf = buf.drop_front(N: *written);
178 else
179 return Status::FromError(error: written.takeError());
180 }
181 return Status();
182}
183
184Status writeSocketIdToPipe(const char *const named_pipe_path,
185 llvm::StringRef socket_id) {
186 Pipe port_name_pipe;
187 // Wait for 10 seconds for pipe to be opened.
188 if (llvm::Error err = port_name_pipe.OpenAsWriter(name: named_pipe_path, child_process_inherit: false,
189 timeout: std::chrono::seconds{10}))
190 return Status::FromError(error: std::move(err));
191
192 return writeSocketIdToPipe(port_pipe&: port_name_pipe, socket_id: socket_id.str());
193}
194
195Status writeSocketIdToPipe(lldb::pipe_t unnamed_pipe,
196 llvm::StringRef socket_id) {
197 Pipe port_pipe{LLDB_INVALID_PIPE, unnamed_pipe};
198 return writeSocketIdToPipe(port_pipe, socket_id: socket_id.str());
199}
200
201void ConnectToRemote(MainLoop &mainloop,
202 GDBRemoteCommunicationServerLLGS &gdb_server,
203 bool reverse_connect, llvm::StringRef host_and_port,
204 const char *const progname, const char *const subcommand,
205 const char *const named_pipe_path, pipe_t unnamed_pipe,
206 shared_fd_t connection_fd) {
207 Status error;
208
209 std::unique_ptr<Connection> connection_up;
210 std::string url;
211
212 if (connection_fd != SharedSocket::kInvalidFD) {
213#ifdef _WIN32
214 NativeSocket sockfd;
215 error = SharedSocket::GetNativeSocket(connection_fd, sockfd);
216 if (error.Fail()) {
217 llvm::errs() << llvm::formatv("error: GetNativeSocket failed: {0}\n",
218 error.AsCString());
219 exit(-1);
220 }
221 connection_up = std::unique_ptr<Connection>(new ConnectionFileDescriptor(
222 new TCPSocket(sockfd, /*should_close=*/true)));
223#else
224 url = llvm::formatv(Fmt: "fd://{0}", Vals&: connection_fd).str();
225
226 // Create the connection.
227 ::fcntl(fd: connection_fd, F_SETFD, FD_CLOEXEC);
228#endif
229 } else if (!host_and_port.empty()) {
230 llvm::Expected<std::string> url_exp =
231 LLGSArgToURL(url_arg: host_and_port, reverse_connect);
232 if (!url_exp) {
233 llvm::errs() << llvm::formatv(Fmt: "error: invalid host:port or URL '{0}': "
234 "{1}\n",
235 Vals&: host_and_port,
236 Vals: llvm::toString(E: url_exp.takeError()));
237 exit(status: -1);
238 }
239
240 url = std::move(url_exp.get());
241 }
242
243 if (!url.empty()) {
244 // Create the connection or server.
245 std::unique_ptr<ConnectionFileDescriptor> conn_fd_up{
246 new ConnectionFileDescriptor};
247 auto connection_result = conn_fd_up->Connect(
248 url,
249 socket_id_callback: [named_pipe_path, unnamed_pipe](llvm::StringRef socket_id) {
250 // If we have a named pipe to write the socket id back to, do that
251 // now.
252 if (named_pipe_path && named_pipe_path[0]) {
253 Status error = writeSocketIdToPipe(named_pipe_path, socket_id);
254 if (error.Fail())
255 llvm::errs() << llvm::formatv(
256 Fmt: "failed to write to the named pipe '{0}': {1}\n",
257 Vals: named_pipe_path, Vals: error.AsCString());
258 }
259 // If we have an unnamed pipe to write the socket id back to, do
260 // that now.
261 else if (unnamed_pipe != LLDB_INVALID_PIPE) {
262 Status error = writeSocketIdToPipe(unnamed_pipe, socket_id);
263 if (error.Fail())
264 llvm::errs() << llvm::formatv(
265 Fmt: "failed to write to the unnamed pipe: {0}\n", Vals&: error);
266 }
267 },
268 error_ptr: &error);
269
270 if (error.Fail()) {
271 llvm::errs() << llvm::formatv(
272 Fmt: "error: failed to connect to client at '{0}': {1}\n", Vals&: url, Vals&: error);
273 exit(status: -1);
274 }
275 if (connection_result != eConnectionStatusSuccess) {
276 llvm::errs() << llvm::formatv(
277 Fmt: "error: failed to connect to client at '{0}' "
278 "(connection status: {1})\n",
279 Vals&: url, Vals: static_cast<int>(connection_result));
280 exit(status: -1);
281 }
282 connection_up = std::move(conn_fd_up);
283 }
284 error = gdb_server.InitializeConnection(connection: std::move(connection_up));
285 if (error.Fail()) {
286 llvm::errs() << llvm::formatv(Fmt: "failed to initialize connection\n", Vals&: error);
287 exit(status: -1);
288 }
289 llvm::outs() << "Connection established.\n";
290}
291
292namespace {
293using namespace llvm::opt;
294
295enum ID {
296 OPT_INVALID = 0, // This is not an option ID.
297#define OPTION(...) LLVM_MAKE_OPT_ID(__VA_ARGS__),
298#include "LLGSOptions.inc"
299#undef OPTION
300};
301
302#define OPTTABLE_STR_TABLE_CODE
303#include "LLGSOptions.inc"
304#undef OPTTABLE_STR_TABLE_CODE
305
306#define OPTTABLE_PREFIXES_TABLE_CODE
307#include "LLGSOptions.inc"
308#undef OPTTABLE_PREFIXES_TABLE_CODE
309
310static constexpr opt::OptTable::Info InfoTable[] = {
311#define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
312#include "LLGSOptions.inc"
313#undef OPTION
314};
315
316class LLGSOptTable : public opt::GenericOptTable {
317public:
318 LLGSOptTable()
319 : opt::GenericOptTable(OptionStrTable, OptionPrefixesTable, InfoTable) {}
320
321 void PrintHelp(llvm::StringRef Name) {
322 std::string Usage =
323 (Name + " [options] [[host]:port] [[--] program args...]").str();
324 OptTable::printHelp(OS&: llvm::outs(), Usage: Usage.c_str(), Title: "lldb-server");
325 llvm::outs() << R"(
326DESCRIPTION
327 lldb-server connects to the LLDB client, which drives the debugging session.
328 If no connection options are given, the [host]:port argument must be present
329 and will denote the address that lldb-server will listen on. [host] defaults
330 to "localhost" if empty. Port can be zero, in which case the port number will
331 be chosen dynamically and written to destinations given by --named-pipe and
332 --pipe arguments.
333
334 If no target is selected at startup, lldb-server can be directed by the LLDB
335 client to launch or attach to a process.
336
337)";
338 }
339};
340} // namespace
341
342int main_gdbserver(int argc, char *argv[]) {
343 Status error;
344 MainLoop mainloop;
345#ifndef _WIN32
346 // Setup signal handlers first thing.
347 signal(SIGPIPE, SIG_IGN);
348 MainLoop::SignalHandleUP sighup_handle =
349 mainloop.RegisterSignal(SIGHUP, callback: sighup_handler, error);
350#endif
351
352 const char *progname = argv[0];
353 const char *subcommand = argv[1];
354 std::string attach_target;
355 std::string named_pipe_path;
356 std::string log_file;
357 StringRef
358 log_channels; // e.g. "lldb process threads:gdb-remote default:linux all"
359 lldb::pipe_t unnamed_pipe = LLDB_INVALID_PIPE;
360 bool reverse_connect = false;
361 shared_fd_t connection_fd = SharedSocket::kInvalidFD;
362
363 // ProcessLaunchInfo launch_info;
364 ProcessAttachInfo attach_info;
365
366 LLGSOptTable Opts;
367 llvm::BumpPtrAllocator Alloc;
368 llvm::StringSaver Saver(Alloc);
369 bool HasError = false;
370 opt::InputArgList Args = Opts.parseArgs(Argc: argc - 1, Argv: argv + 1, Unknown: OPT_UNKNOWN,
371 Saver, ErrorFn: [&](llvm::StringRef Msg) {
372 WithColor::error() << Msg << "\n";
373 HasError = true;
374 });
375 std::string Name =
376 (llvm::sys::path::filename(path: argv[0]) + " g[dbserver]").str();
377 std::string HelpText =
378 "Use '" + Name + " --help' for a complete list of options.\n";
379 if (HasError) {
380 llvm::errs() << HelpText;
381 return 1;
382 }
383
384 if (Args.hasArg(OPT_help)) {
385 Opts.PrintHelp(Name);
386 return 0;
387 }
388
389#ifndef _WIN32
390 if (Args.hasArg(OPT_setsid)) {
391 // Put llgs into a new session. Terminals group processes
392 // into sessions and when a special terminal key sequences
393 // (like control+c) are typed they can cause signals to go out to
394 // all processes in a session. Using this --setsid (-S) option
395 // will cause debugserver to run in its own sessions and be free
396 // from such issues.
397 //
398 // This is useful when llgs is spawned from a command
399 // line application that uses llgs to do the debugging,
400 // yet that application doesn't want llgs receiving the
401 // signals sent to the session (i.e. dying when anyone hits ^C).
402 {
403 const ::pid_t new_sid = setsid();
404 if (new_sid == -1) {
405 WithColor::warning()
406 << llvm::formatv(Fmt: "failed to set new session id for {0} ({1})\n",
407 LLGS_PROGRAM_NAME, Vals: llvm::sys::StrError());
408 }
409 }
410 }
411#endif
412
413 log_file = Args.getLastArgValue(Id: OPT_log_file).str();
414 log_channels = Args.getLastArgValue(Id: OPT_log_channels);
415 named_pipe_path = Args.getLastArgValue(Id: OPT_named_pipe).str();
416 reverse_connect = Args.hasArg(Ids: OPT_reverse_connect);
417 attach_target = Args.getLastArgValue(Id: OPT_attach).str();
418 if (Args.hasArg(OPT_pipe)) {
419 uint64_t Arg;
420 if (!llvm::to_integer(Args.getLastArgValue(Id: OPT_pipe), Arg)) {
421 WithColor::error() << "invalid '--pipe' argument\n" << HelpText;
422 return 1;
423 }
424 unnamed_pipe = (pipe_t)Arg;
425 }
426 if (Args.hasArg(OPT_fd)) {
427 int64_t fd;
428 if (!llvm::to_integer(Args.getLastArgValue(Id: OPT_fd), fd)) {
429 WithColor::error() << "invalid '--fd' argument\n" << HelpText;
430 return 1;
431 }
432 connection_fd = (shared_fd_t)fd;
433 }
434
435 if (!LLDBServerUtilities::SetupLogging(
436 log_file, log_channels,
437 LLDB_LOG_OPTION_PREPEND_TIMESTAMP |
438 LLDB_LOG_OPTION_PREPEND_FILE_FUNCTION))
439 return -1;
440
441 std::vector<llvm::StringRef> Inputs;
442 for (opt::Arg *Arg : Args.filtered(OPT_INPUT))
443 Inputs.push_back(Arg->getValue());
444 if (opt::Arg *Arg = Args.getLastArg(OPT_REM)) {
445 for (const char *Val : Arg->getValues())
446 Inputs.push_back(Val);
447 }
448 if (Inputs.empty() && connection_fd == SharedSocket::kInvalidFD) {
449 WithColor::error() << "no connection arguments\n" << HelpText;
450 return 1;
451 }
452
453 NativeProcessManager manager(mainloop);
454 GDBRemoteCommunicationServerLLGS gdb_server(mainloop, manager);
455
456 llvm::StringRef host_and_port;
457 if (!Inputs.empty() && connection_fd == SharedSocket::kInvalidFD) {
458 host_and_port = Inputs.front();
459 Inputs.erase(position: Inputs.begin());
460 }
461
462 // Any arguments left over are for the program that we need to launch. If
463 // there
464 // are no arguments, then the GDB server will start up and wait for an 'A'
465 // packet
466 // to launch a program, or a vAttach packet to attach to an existing process,
467 // unless
468 // explicitly asked to attach with the --attach={pid|program_name} form.
469 if (!attach_target.empty())
470 handle_attach(gdb_server, attach_target);
471 else if (!Inputs.empty())
472 handle_launch(gdb_server, Arguments: Inputs);
473
474 // Print version info.
475 printf(format: "%s-%s\n", LLGS_PROGRAM_NAME, LLGS_VERSION_STR);
476
477 ConnectToRemote(mainloop, gdb_server, reverse_connect, host_and_port,
478 progname, subcommand, named_pipe_path: named_pipe_path.c_str(),
479 unnamed_pipe, connection_fd);
480
481 if (!gdb_server.IsConnected()) {
482 fprintf(stderr, format: "no connection information provided, unable to run\n");
483 return 1;
484 }
485
486 Status ret = mainloop.Run();
487 if (ret.Fail()) {
488 fprintf(stderr, format: "lldb-server terminating due to error: %s\n",
489 ret.AsCString());
490 return 1;
491 }
492 fprintf(stderr, format: "lldb-server exiting...\n");
493
494 return 0;
495}
496

source code of lldb/tools/lldb-server/lldb-gdbserver.cpp