1 //===-- Socket.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 "lldb/Host/Socket.h"
10 
11 #include "lldb/Host/Config.h"
12 #include "lldb/Host/Host.h"
13 #include "lldb/Host/SocketAddress.h"
14 #include "lldb/Host/StringConvert.h"
15 #include "lldb/Host/common/TCPSocket.h"
16 #include "lldb/Host/common/UDPSocket.h"
17 #include "lldb/Utility/Log.h"
18 #include "lldb/Utility/RegularExpression.h"
19 
20 #include "llvm/ADT/STLExtras.h"
21 #include "llvm/Support/Errno.h"
22 #include "llvm/Support/Error.h"
23 #include "llvm/Support/WindowsError.h"
24 
25 #if LLDB_ENABLE_POSIX
26 #include "lldb/Host/posix/DomainSocket.h"
27 
28 #include <arpa/inet.h>
29 #include <netdb.h>
30 #include <netinet/in.h>
31 #include <netinet/tcp.h>
32 #include <sys/socket.h>
33 #include <sys/un.h>
34 #include <unistd.h>
35 #endif
36 
37 #ifdef __linux__
38 #include "lldb/Host/linux/AbstractSocket.h"
39 #endif
40 
41 #ifdef __ANDROID__
42 #include <arpa/inet.h>
43 #include <asm-generic/errno-base.h>
44 #include <errno.h>
45 #include <linux/tcp.h>
46 #include <fcntl.h>
47 #include <sys/syscall.h>
48 #include <unistd.h>
49 #endif // __ANDROID__
50 
51 using namespace lldb;
52 using namespace lldb_private;
53 
54 #if defined(_WIN32)
55 typedef const char *set_socket_option_arg_type;
56 typedef char *get_socket_option_arg_type;
57 const NativeSocket Socket::kInvalidSocketValue = INVALID_SOCKET;
58 #else  // #if defined(_WIN32)
59 typedef const void *set_socket_option_arg_type;
60 typedef void *get_socket_option_arg_type;
61 const NativeSocket Socket::kInvalidSocketValue = -1;
62 #endif // #if defined(_WIN32)
63 
64 namespace {
65 
66 bool IsInterrupted() {
67 #if defined(_WIN32)
68   return ::WSAGetLastError() == WSAEINTR;
69 #else
70   return errno == EINTR;
71 #endif
72 }
73 }
74 
75 Socket::Socket(SocketProtocol protocol, bool should_close,
76                bool child_processes_inherit)
77     : IOObject(eFDTypeSocket), m_protocol(protocol),
78       m_socket(kInvalidSocketValue),
79       m_child_processes_inherit(child_processes_inherit),
80       m_should_close_fd(should_close) {}
81 
82 Socket::~Socket() { Close(); }
83 
84 llvm::Error Socket::Initialize() {
85 #if defined(_WIN32)
86   auto wVersion = WINSOCK_VERSION;
87   WSADATA wsaData;
88   int err = ::WSAStartup(wVersion, &wsaData);
89   if (err == 0) {
90     if (wsaData.wVersion < wVersion) {
91       WSACleanup();
92       return llvm::make_error<llvm::StringError>(
93           "WSASock version is not expected.", llvm::inconvertibleErrorCode());
94     }
95   } else {
96     return llvm::errorCodeToError(llvm::mapWindowsError(::WSAGetLastError()));
97   }
98 #endif
99 
100   return llvm::Error::success();
101 }
102 
103 void Socket::Terminate() {
104 #if defined(_WIN32)
105   ::WSACleanup();
106 #endif
107 }
108 
109 std::unique_ptr<Socket> Socket::Create(const SocketProtocol protocol,
110                                        bool child_processes_inherit,
111                                        Status &error) {
112   error.Clear();
113 
114   std::unique_ptr<Socket> socket_up;
115   switch (protocol) {
116   case ProtocolTcp:
117     socket_up =
118         std::make_unique<TCPSocket>(true, child_processes_inherit);
119     break;
120   case ProtocolUdp:
121     socket_up =
122         std::make_unique<UDPSocket>(true, child_processes_inherit);
123     break;
124   case ProtocolUnixDomain:
125 #if LLDB_ENABLE_POSIX
126     socket_up =
127         std::make_unique<DomainSocket>(true, child_processes_inherit);
128 #else
129     error.SetErrorString(
130         "Unix domain sockets are not supported on this platform.");
131 #endif
132     break;
133   case ProtocolUnixAbstract:
134 #ifdef __linux__
135     socket_up =
136         std::make_unique<AbstractSocket>(child_processes_inherit);
137 #else
138     error.SetErrorString(
139         "Abstract domain sockets are not supported on this platform.");
140 #endif
141     break;
142   }
143 
144   if (error.Fail())
145     socket_up.reset();
146 
147   return socket_up;
148 }
149 
150 llvm::Expected<std::unique_ptr<Socket>>
151 Socket::TcpConnect(llvm::StringRef host_and_port,
152                    bool child_processes_inherit) {
153   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
154   LLDB_LOG(log, "host_and_port = {0}", host_and_port);
155 
156   Status error;
157   std::unique_ptr<Socket> connect_socket(
158       Create(ProtocolTcp, child_processes_inherit, error));
159   if (error.Fail())
160     return error.ToError();
161 
162   error = connect_socket->Connect(host_and_port);
163   if (error.Success())
164     return std::move(connect_socket);
165 
166   return error.ToError();
167 }
168 
169 llvm::Expected<std::unique_ptr<TCPSocket>>
170 Socket::TcpListen(llvm::StringRef host_and_port, bool child_processes_inherit,
171                   Predicate<uint16_t> *predicate, int backlog) {
172   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
173   LLDB_LOG(log, "host_and_port = {0}", host_and_port);
174 
175   Status error;
176   std::string host_str;
177   std::string port_str;
178   int32_t port = INT32_MIN;
179   if (!DecodeHostAndPort(host_and_port, host_str, port_str, port, &error))
180     return error.ToError();
181 
182   std::unique_ptr<TCPSocket> listen_socket(
183       new TCPSocket(true, child_processes_inherit));
184 
185   error = listen_socket->Listen(host_and_port, backlog);
186   if (error.Fail())
187     return error.ToError();
188 
189   // We were asked to listen on port zero which means we must now read the
190   // actual port that was given to us as port zero is a special code for
191   // "find an open port for me".
192   if (port == 0)
193     port = listen_socket->GetLocalPortNumber();
194 
195   // Set the port predicate since when doing a listen://<host>:<port> it
196   // often needs to accept the incoming connection which is a blocking system
197   // call. Allowing access to the bound port using a predicate allows us to
198   // wait for the port predicate to be set to a non-zero value from another
199   // thread in an efficient manor.
200   if (predicate)
201     predicate->SetValue(port, eBroadcastAlways);
202   return std::move(listen_socket);
203 }
204 
205 llvm::Expected<std::unique_ptr<UDPSocket>>
206 Socket::UdpConnect(llvm::StringRef host_and_port,
207                    bool child_processes_inherit) {
208   return UDPSocket::Connect(host_and_port, child_processes_inherit);
209 }
210 
211 Status Socket::UnixDomainConnect(llvm::StringRef name,
212                                  bool child_processes_inherit,
213                                  Socket *&socket) {
214   Status error;
215   std::unique_ptr<Socket> connect_socket(
216       Create(ProtocolUnixDomain, child_processes_inherit, error));
217   if (error.Fail())
218     return error;
219 
220   error = connect_socket->Connect(name);
221   if (error.Success())
222     socket = connect_socket.release();
223 
224   return error;
225 }
226 
227 Status Socket::UnixDomainAccept(llvm::StringRef name,
228                                 bool child_processes_inherit, Socket *&socket) {
229   Status error;
230   std::unique_ptr<Socket> listen_socket(
231       Create(ProtocolUnixDomain, child_processes_inherit, error));
232   if (error.Fail())
233     return error;
234 
235   error = listen_socket->Listen(name, 5);
236   if (error.Fail())
237     return error;
238 
239   error = listen_socket->Accept(socket);
240   return error;
241 }
242 
243 Status Socket::UnixAbstractConnect(llvm::StringRef name,
244                                    bool child_processes_inherit,
245                                    Socket *&socket) {
246   Status error;
247   std::unique_ptr<Socket> connect_socket(
248       Create(ProtocolUnixAbstract, child_processes_inherit, error));
249   if (error.Fail())
250     return error;
251 
252   error = connect_socket->Connect(name);
253   if (error.Success())
254     socket = connect_socket.release();
255   return error;
256 }
257 
258 Status Socket::UnixAbstractAccept(llvm::StringRef name,
259                                   bool child_processes_inherit,
260                                   Socket *&socket) {
261   Status error;
262   std::unique_ptr<Socket> listen_socket(
263       Create(ProtocolUnixAbstract, child_processes_inherit, error));
264   if (error.Fail())
265     return error;
266 
267   error = listen_socket->Listen(name, 5);
268   if (error.Fail())
269     return error;
270 
271   error = listen_socket->Accept(socket);
272   return error;
273 }
274 
275 bool Socket::DecodeHostAndPort(llvm::StringRef host_and_port,
276                                std::string &host_str, std::string &port_str,
277                                int32_t &port, Status *error_ptr) {
278   static RegularExpression g_regex(
279       llvm::StringRef("([^:]+|\\[[0-9a-fA-F:]+.*\\]):([0-9]+)"));
280   llvm::SmallVector<llvm::StringRef, 3> matches;
281   if (g_regex.Execute(host_and_port, &matches)) {
282     host_str = matches[1].str();
283     port_str = matches[2].str();
284     // IPv6 addresses are wrapped in [] when specified with ports
285     if (host_str.front() == '[' && host_str.back() == ']')
286       host_str = host_str.substr(1, host_str.size() - 2);
287     bool ok = false;
288     port = StringConvert::ToUInt32(port_str.c_str(), UINT32_MAX, 10, &ok);
289     if (ok && port <= UINT16_MAX) {
290       if (error_ptr)
291         error_ptr->Clear();
292       return true;
293     }
294     // port is too large
295     if (error_ptr)
296       error_ptr->SetErrorStringWithFormat(
297           "invalid host:port specification: '%s'", host_and_port.str().c_str());
298     return false;
299   }
300 
301   // If this was unsuccessful, then check if it's simply a signed 32-bit
302   // integer, representing a port with an empty host.
303   host_str.clear();
304   port_str.clear();
305   if (to_integer(host_and_port, port, 10) && port < UINT16_MAX) {
306     port_str = std::string(host_and_port);
307     if (error_ptr)
308       error_ptr->Clear();
309     return true;
310   }
311 
312   if (error_ptr)
313     error_ptr->SetErrorStringWithFormat("invalid host:port specification: '%s'",
314                                         host_and_port.str().c_str());
315   return false;
316 }
317 
318 IOObject::WaitableHandle Socket::GetWaitableHandle() {
319   // TODO: On Windows, use WSAEventSelect
320   return m_socket;
321 }
322 
323 Status Socket::Read(void *buf, size_t &num_bytes) {
324   Status error;
325   int bytes_received = 0;
326   do {
327     bytes_received = ::recv(m_socket, static_cast<char *>(buf), num_bytes, 0);
328   } while (bytes_received < 0 && IsInterrupted());
329 
330   if (bytes_received < 0) {
331     SetLastError(error);
332     num_bytes = 0;
333   } else
334     num_bytes = bytes_received;
335 
336   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_COMMUNICATION));
337   if (log) {
338     LLDB_LOGF(log,
339               "%p Socket::Read() (socket = %" PRIu64
340               ", src = %p, src_len = %" PRIu64 ", flags = 0) => %" PRIi64
341               " (error = %s)",
342               static_cast<void *>(this), static_cast<uint64_t>(m_socket), buf,
343               static_cast<uint64_t>(num_bytes),
344               static_cast<int64_t>(bytes_received), error.AsCString());
345   }
346 
347   return error;
348 }
349 
350 Status Socket::Write(const void *buf, size_t &num_bytes) {
351   const size_t src_len = num_bytes;
352   Status error;
353   int bytes_sent = 0;
354   do {
355     bytes_sent = Send(buf, num_bytes);
356   } while (bytes_sent < 0 && IsInterrupted());
357 
358   if (bytes_sent < 0) {
359     SetLastError(error);
360     num_bytes = 0;
361   } else
362     num_bytes = bytes_sent;
363 
364   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_COMMUNICATION));
365   if (log) {
366     LLDB_LOGF(log,
367               "%p Socket::Write() (socket = %" PRIu64
368               ", src = %p, src_len = %" PRIu64 ", flags = 0) => %" PRIi64
369               " (error = %s)",
370               static_cast<void *>(this), static_cast<uint64_t>(m_socket), buf,
371               static_cast<uint64_t>(src_len),
372               static_cast<int64_t>(bytes_sent), error.AsCString());
373   }
374 
375   return error;
376 }
377 
378 Status Socket::PreDisconnect() {
379   Status error;
380   return error;
381 }
382 
383 Status Socket::Close() {
384   Status error;
385   if (!IsValid() || !m_should_close_fd)
386     return error;
387 
388   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
389   LLDB_LOGF(log, "%p Socket::Close (fd = %" PRIu64 ")",
390             static_cast<void *>(this), static_cast<uint64_t>(m_socket));
391 
392 #if defined(_WIN32)
393   bool success = !!closesocket(m_socket);
394 #else
395   bool success = !!::close(m_socket);
396 #endif
397   // A reference to a FD was passed in, set it to an invalid value
398   m_socket = kInvalidSocketValue;
399   if (!success) {
400     SetLastError(error);
401   }
402 
403   return error;
404 }
405 
406 int Socket::GetOption(int level, int option_name, int &option_value) {
407   get_socket_option_arg_type option_value_p =
408       reinterpret_cast<get_socket_option_arg_type>(&option_value);
409   socklen_t option_value_size = sizeof(int);
410   return ::getsockopt(m_socket, level, option_name, option_value_p,
411                       &option_value_size);
412 }
413 
414 int Socket::SetOption(int level, int option_name, int option_value) {
415   set_socket_option_arg_type option_value_p =
416       reinterpret_cast<get_socket_option_arg_type>(&option_value);
417   return ::setsockopt(m_socket, level, option_name, option_value_p,
418                       sizeof(option_value));
419 }
420 
421 size_t Socket::Send(const void *buf, const size_t num_bytes) {
422   return ::send(m_socket, static_cast<const char *>(buf), num_bytes, 0);
423 }
424 
425 void Socket::SetLastError(Status &error) {
426 #if defined(_WIN32)
427   error.SetError(::WSAGetLastError(), lldb::eErrorTypeWin32);
428 #else
429   error.SetErrorToErrno();
430 #endif
431 }
432 
433 NativeSocket Socket::CreateSocket(const int domain, const int type,
434                                   const int protocol,
435                                   bool child_processes_inherit, Status &error) {
436   error.Clear();
437   auto socket_type = type;
438 #ifdef SOCK_CLOEXEC
439   if (!child_processes_inherit)
440     socket_type |= SOCK_CLOEXEC;
441 #endif
442   auto sock = ::socket(domain, socket_type, protocol);
443   if (sock == kInvalidSocketValue)
444     SetLastError(error);
445 
446   return sock;
447 }
448 
449 NativeSocket Socket::AcceptSocket(NativeSocket sockfd, struct sockaddr *addr,
450                                   socklen_t *addrlen,
451                                   bool child_processes_inherit, Status &error) {
452   error.Clear();
453 #if defined(ANDROID_USE_ACCEPT_WORKAROUND)
454   // Hack:
455   // This enables static linking lldb-server to an API 21 libc, but still
456   // having it run on older devices. It is necessary because API 21 libc's
457   // implementation of accept() uses the accept4 syscall(), which is not
458   // available in older kernels. Using an older libc would fix this issue, but
459   // introduce other ones, as the old libraries were quite buggy.
460   int fd = syscall(__NR_accept, sockfd, addr, addrlen);
461   if (fd >= 0 && !child_processes_inherit) {
462     int flags = ::fcntl(fd, F_GETFD);
463     if (flags != -1 && ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC) != -1)
464       return fd;
465     SetLastError(error);
466     close(fd);
467   }
468   return fd;
469 #elif defined(SOCK_CLOEXEC) && defined(HAVE_ACCEPT4)
470   int flags = 0;
471   if (!child_processes_inherit) {
472     flags |= SOCK_CLOEXEC;
473   }
474   NativeSocket fd = llvm::sys::RetryAfterSignal(
475       static_cast<NativeSocket>(-1), ::accept4, sockfd, addr, addrlen, flags);
476 #else
477   NativeSocket fd = llvm::sys::RetryAfterSignal(
478       static_cast<NativeSocket>(-1), ::accept, sockfd, addr, addrlen);
479 #endif
480   if (fd == kInvalidSocketValue)
481     SetLastError(error);
482   return fd;
483 }
484