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/Socket.h"
28 #include "lldb/Host/common/NativeProcessProtocol.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
58 using namespace llvm;
59 using namespace lldb;
60 using namespace lldb_private;
61 using namespace lldb_private::lldb_server;
62 using namespace lldb_private::process_gdb_remote;
63
64 namespace {
65 #if defined(__linux__)
66 typedef process_linux::NativeProcessLinux::Manager NativeProcessManager;
67 #elif defined(__FreeBSD__)
68 typedef process_freebsd::NativeProcessFreeBSD::Manager NativeProcessManager;
69 #elif defined(__NetBSD__)
70 typedef process_netbsd::NativeProcessNetBSD::Manager NativeProcessManager;
71 #elif defined(_WIN32)
72 typedef NativeProcessWindows::Manager NativeProcessManager;
73 #else
74 // Dummy implementation to make sure the code compiles
75 class NativeProcessManager : public NativeProcessProtocol::Manager {
76 public:
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
96 static int g_sighup_received_count = 0;
97
sighup_handler(MainLoopBase & mainloop)98 static void sighup_handler(MainLoopBase &mainloop) {
99 ++g_sighup_received_count;
100
101 Log *log = GetLog(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
handle_attach_to_pid(GDBRemoteCommunicationServerLLGS & gdb_server,lldb::pid_t pid)110 void 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, "error: failed to attach to pid %" PRIu64 ": %s\n", pid,
115 error.AsCString());
116 exit(1);
117 }
118 }
119
handle_attach_to_process_name(GDBRemoteCommunicationServerLLGS & gdb_server,const std::string & process_name)120 void handle_attach_to_process_name(GDBRemoteCommunicationServerLLGS &gdb_server,
121 const std::string &process_name) {
122 // FIXME implement.
123 }
124
handle_attach(GDBRemoteCommunicationServerLLGS & gdb_server,const std::string & attach_target)125 void 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(attach_target.c_str(), &end_p, 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, static_cast<lldb::pid_t>(pid));
139 else
140 handle_attach_to_process_name(gdb_server, attach_target);
141 }
142
handle_launch(GDBRemoteCommunicationServerLLGS & gdb_server,llvm::ArrayRef<llvm::StringRef> Arguments)143 void 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(Arguments), true);
149
150 llvm::SmallString<64> cwd;
151 if (std::error_code ec = llvm::sys::fs::current_path(cwd)) {
152 llvm::errs() << "Error getting current directory: " << ec.message() << "\n";
153 exit(1);
154 }
155 FileSpec cwd_spec(cwd);
156 FileSystem::Instance().Resolve(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("error: failed to launch '{0}': {1}\n",
165 Arguments[0], error);
166 exit(1);
167 }
168 }
169
writeSocketIdToPipe(Pipe & port_pipe,llvm::StringRef socket_id)170 Status writeSocketIdToPipe(Pipe &port_pipe, llvm::StringRef socket_id) {
171 size_t bytes_written = 0;
172 // Write the port number as a C string with the NULL terminator.
173 return port_pipe.Write(socket_id.data(), socket_id.size() + 1, bytes_written);
174 }
175
writeSocketIdToPipe(const char * const named_pipe_path,llvm::StringRef socket_id)176 Status writeSocketIdToPipe(const char *const named_pipe_path,
177 llvm::StringRef socket_id) {
178 Pipe port_name_pipe;
179 // Wait for 10 seconds for pipe to be opened.
180 auto error = port_name_pipe.OpenAsWriterWithTimeout(named_pipe_path, false,
181 std::chrono::seconds{10});
182 if (error.Fail())
183 return error;
184 return writeSocketIdToPipe(port_name_pipe, socket_id);
185 }
186
writeSocketIdToPipe(lldb::pipe_t unnamed_pipe,llvm::StringRef socket_id)187 Status writeSocketIdToPipe(lldb::pipe_t unnamed_pipe,
188 llvm::StringRef socket_id) {
189 Pipe port_pipe{LLDB_INVALID_PIPE, unnamed_pipe};
190 return writeSocketIdToPipe(port_pipe, socket_id);
191 }
192
ConnectToRemote(MainLoop & mainloop,GDBRemoteCommunicationServerLLGS & gdb_server,bool reverse_connect,llvm::StringRef host_and_port,const char * const progname,const char * const subcommand,const char * const named_pipe_path,pipe_t unnamed_pipe,int connection_fd)193 void ConnectToRemote(MainLoop &mainloop,
194 GDBRemoteCommunicationServerLLGS &gdb_server,
195 bool reverse_connect, llvm::StringRef host_and_port,
196 const char *const progname, const char *const subcommand,
197 const char *const named_pipe_path, pipe_t unnamed_pipe,
198 int connection_fd) {
199 Status error;
200
201 std::unique_ptr<Connection> connection_up;
202 std::string url;
203
204 if (connection_fd != -1) {
205 url = llvm::formatv("fd://{0}", connection_fd).str();
206
207 // Create the connection.
208 #if LLDB_ENABLE_POSIX && !defined _WIN32
209 ::fcntl(connection_fd, F_SETFD, FD_CLOEXEC);
210 #endif
211 } else if (!host_and_port.empty()) {
212 llvm::Expected<std::string> url_exp =
213 LLGSArgToURL(host_and_port, reverse_connect);
214 if (!url_exp) {
215 llvm::errs() << llvm::formatv("error: invalid host:port or URL '{0}': "
216 "{1}\n",
217 host_and_port,
218 llvm::toString(url_exp.takeError()));
219 exit(-1);
220 }
221
222 url = std::move(url_exp.get());
223 }
224
225 if (!url.empty()) {
226 // Create the connection or server.
227 std::unique_ptr<ConnectionFileDescriptor> conn_fd_up{
228 new ConnectionFileDescriptor};
229 auto connection_result = conn_fd_up->Connect(
230 url,
231 [named_pipe_path, unnamed_pipe](llvm::StringRef socket_id) {
232 // If we have a named pipe to write the socket id back to, do that
233 // now.
234 if (named_pipe_path && named_pipe_path[0]) {
235 Status error = writeSocketIdToPipe(named_pipe_path, socket_id);
236 if (error.Fail())
237 llvm::errs() << llvm::formatv(
238 "failed to write to the named peipe '{0}': {1}\n",
239 named_pipe_path, error.AsCString());
240 }
241 // If we have an unnamed pipe to write the socket id back to, do
242 // that now.
243 else if (unnamed_pipe != LLDB_INVALID_PIPE) {
244 Status error = writeSocketIdToPipe(unnamed_pipe, socket_id);
245 if (error.Fail())
246 llvm::errs() << llvm::formatv(
247 "failed to write to the unnamed pipe: {0}\n", error);
248 }
249 },
250 &error);
251
252 if (error.Fail()) {
253 llvm::errs() << llvm::formatv(
254 "error: failed to connect to client at '{0}': {1}\n", url, error);
255 exit(-1);
256 }
257 if (connection_result != eConnectionStatusSuccess) {
258 llvm::errs() << llvm::formatv(
259 "error: failed to connect to client at '{0}' "
260 "(connection status: {1})\n",
261 url, static_cast<int>(connection_result));
262 exit(-1);
263 }
264 connection_up = std::move(conn_fd_up);
265 }
266 error = gdb_server.InitializeConnection(std::move(connection_up));
267 if (error.Fail()) {
268 llvm::errs() << llvm::formatv("failed to initialize connection\n", error);
269 exit(-1);
270 }
271 llvm::outs() << "Connection established.\n";
272 }
273
274 namespace {
275 using namespace llvm::opt;
276
277 enum ID {
278 OPT_INVALID = 0, // This is not an option ID.
279 #define OPTION(...) LLVM_MAKE_OPT_ID(__VA_ARGS__),
280 #include "LLGSOptions.inc"
281 #undef OPTION
282 };
283
284 #define PREFIX(NAME, VALUE) \
285 constexpr llvm::StringLiteral NAME##_init[] = VALUE; \
286 constexpr llvm::ArrayRef<llvm::StringLiteral> NAME( \
287 NAME##_init, std::size(NAME##_init) - 1);
288 #include "LLGSOptions.inc"
289 #undef PREFIX
290
291 static constexpr opt::OptTable::Info InfoTable[] = {
292 #define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
293 #include "LLGSOptions.inc"
294 #undef OPTION
295 };
296
297 class LLGSOptTable : public opt::GenericOptTable {
298 public:
LLGSOptTable()299 LLGSOptTable() : opt::GenericOptTable(InfoTable) {}
300
PrintHelp(llvm::StringRef Name)301 void PrintHelp(llvm::StringRef Name) {
302 std::string Usage =
303 (Name + " [options] [[host]:port] [[--] program args...]").str();
304 OptTable::printHelp(llvm::outs(), Usage.c_str(), "lldb-server");
305 llvm::outs() << R"(
306 DESCRIPTION
307 lldb-server connects to the LLDB client, which drives the debugging session.
308 If no connection options are given, the [host]:port argument must be present
309 and will denote the address that lldb-server will listen on. [host] defaults
310 to "localhost" if empty. Port can be zero, in which case the port number will
311 be chosen dynamically and written to destinations given by --named-pipe and
312 --pipe arguments.
313
314 If no target is selected at startup, lldb-server can be directed by the LLDB
315 client to launch or attach to a process.
316
317 )";
318 }
319 };
320 } // namespace
321
main_gdbserver(int argc,char * argv[])322 int main_gdbserver(int argc, char *argv[]) {
323 Status error;
324 MainLoop mainloop;
325 #ifndef _WIN32
326 // Setup signal handlers first thing.
327 signal(SIGPIPE, SIG_IGN);
328 MainLoop::SignalHandleUP sighup_handle =
329 mainloop.RegisterSignal(SIGHUP, sighup_handler, error);
330 #endif
331
332 const char *progname = argv[0];
333 const char *subcommand = argv[1];
334 std::string attach_target;
335 std::string named_pipe_path;
336 std::string log_file;
337 StringRef
338 log_channels; // e.g. "lldb process threads:gdb-remote default:linux all"
339 lldb::pipe_t unnamed_pipe = LLDB_INVALID_PIPE;
340 bool reverse_connect = false;
341 int connection_fd = -1;
342
343 // ProcessLaunchInfo launch_info;
344 ProcessAttachInfo attach_info;
345
346 LLGSOptTable Opts;
347 llvm::BumpPtrAllocator Alloc;
348 llvm::StringSaver Saver(Alloc);
349 bool HasError = false;
350 opt::InputArgList Args = Opts.parseArgs(argc - 1, argv + 1, OPT_UNKNOWN,
351 Saver, [&](llvm::StringRef Msg) {
352 WithColor::error() << Msg << "\n";
353 HasError = true;
354 });
355 std::string Name =
356 (llvm::sys::path::filename(argv[0]) + " g[dbserver]").str();
357 std::string HelpText =
358 "Use '" + Name + " --help' for a complete list of options.\n";
359 if (HasError) {
360 llvm::errs() << HelpText;
361 return 1;
362 }
363
364 if (Args.hasArg(OPT_help)) {
365 Opts.PrintHelp(Name);
366 return 0;
367 }
368
369 #ifndef _WIN32
370 if (Args.hasArg(OPT_setsid)) {
371 // Put llgs into a new session. Terminals group processes
372 // into sessions and when a special terminal key sequences
373 // (like control+c) are typed they can cause signals to go out to
374 // all processes in a session. Using this --setsid (-S) option
375 // will cause debugserver to run in its own sessions and be free
376 // from such issues.
377 //
378 // This is useful when llgs is spawned from a command
379 // line application that uses llgs to do the debugging,
380 // yet that application doesn't want llgs receiving the
381 // signals sent to the session (i.e. dying when anyone hits ^C).
382 {
383 const ::pid_t new_sid = setsid();
384 if (new_sid == -1) {
385 WithColor::warning()
386 << llvm::formatv("failed to set new session id for {0} ({1})\n",
387 LLGS_PROGRAM_NAME, llvm::sys::StrError());
388 }
389 }
390 }
391 #endif
392
393 log_file = Args.getLastArgValue(OPT_log_file).str();
394 log_channels = Args.getLastArgValue(OPT_log_channels);
395 named_pipe_path = Args.getLastArgValue(OPT_named_pipe).str();
396 reverse_connect = Args.hasArg(OPT_reverse_connect);
397 attach_target = Args.getLastArgValue(OPT_attach).str();
398 if (Args.hasArg(OPT_pipe)) {
399 uint64_t Arg;
400 if (!llvm::to_integer(Args.getLastArgValue(OPT_pipe), Arg)) {
401 WithColor::error() << "invalid '--pipe' argument\n" << HelpText;
402 return 1;
403 }
404 unnamed_pipe = (pipe_t)Arg;
405 }
406 if (Args.hasArg(OPT_fd)) {
407 if (!llvm::to_integer(Args.getLastArgValue(OPT_fd), connection_fd)) {
408 WithColor::error() << "invalid '--fd' argument\n" << HelpText;
409 return 1;
410 }
411 }
412
413 if (!LLDBServerUtilities::SetupLogging(
414 log_file, log_channels,
415 LLDB_LOG_OPTION_PREPEND_TIMESTAMP |
416 LLDB_LOG_OPTION_PREPEND_FILE_FUNCTION))
417 return -1;
418
419 std::vector<llvm::StringRef> Inputs;
420 for (opt::Arg *Arg : Args.filtered(OPT_INPUT))
421 Inputs.push_back(Arg->getValue());
422 if (opt::Arg *Arg = Args.getLastArg(OPT_REM)) {
423 for (const char *Val : Arg->getValues())
424 Inputs.push_back(Val);
425 }
426 if (Inputs.empty() && connection_fd == -1) {
427 WithColor::error() << "no connection arguments\n" << HelpText;
428 return 1;
429 }
430
431 NativeProcessManager manager(mainloop);
432 GDBRemoteCommunicationServerLLGS gdb_server(mainloop, manager);
433
434 llvm::StringRef host_and_port;
435 if (!Inputs.empty()) {
436 host_and_port = Inputs.front();
437 Inputs.erase(Inputs.begin());
438 }
439
440 // Any arguments left over are for the program that we need to launch. If
441 // there
442 // are no arguments, then the GDB server will start up and wait for an 'A'
443 // packet
444 // to launch a program, or a vAttach packet to attach to an existing process,
445 // unless
446 // explicitly asked to attach with the --attach={pid|program_name} form.
447 if (!attach_target.empty())
448 handle_attach(gdb_server, attach_target);
449 else if (!Inputs.empty())
450 handle_launch(gdb_server, Inputs);
451
452 // Print version info.
453 printf("%s-%s\n", LLGS_PROGRAM_NAME, LLGS_VERSION_STR);
454
455 ConnectToRemote(mainloop, gdb_server, reverse_connect, host_and_port,
456 progname, subcommand, named_pipe_path.c_str(),
457 unnamed_pipe, connection_fd);
458
459 if (!gdb_server.IsConnected()) {
460 fprintf(stderr, "no connection information provided, unable to run\n");
461 return 1;
462 }
463
464 Status ret = mainloop.Run();
465 if (ret.Fail()) {
466 fprintf(stderr, "lldb-server terminating due to error: %s\n",
467 ret.AsCString());
468 return 1;
469 }
470 fprintf(stderr, "lldb-server exiting...\n");
471
472 return 0;
473 }
474