1 //===-- Socket.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 "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 #ifndef LLDB_DISABLE_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, should_close), m_protocol(protocol),
78       m_socket(kInvalidSocketValue),
79       m_child_processes_inherit(child_processes_inherit) {}
80 
81 Socket::~Socket() { Close(); }
82 
83 llvm::Error Socket::Initialize() {
84 #if defined(_WIN32)
85   auto wVersion = WINSOCK_VERSION;
86   WSADATA wsaData;
87   int err = ::WSAStartup(wVersion, &wsaData);
88   if (err == 0) {
89     if (wsaData.wVersion < wVersion) {
90       WSACleanup();
91       return llvm::make_error<llvm::StringError>(
92           "WSASock version is not expected.", llvm::inconvertibleErrorCode());
93     }
94   } else {
95     return llvm::errorCodeToError(llvm::mapWindowsError(::WSAGetLastError()));
96   }
97 #endif
98 
99   return llvm::Error::success();
100 }
101 
102 void Socket::Terminate() {
103 #if defined(_WIN32)
104   ::WSACleanup();
105 #endif
106 }
107 
108 std::unique_ptr<Socket> Socket::Create(const SocketProtocol protocol,
109                                        bool child_processes_inherit,
110                                        Status &error) {
111   error.Clear();
112 
113   std::unique_ptr<Socket> socket_up;
114   switch (protocol) {
115   case ProtocolTcp:
116     socket_up =
117         std::make_unique<TCPSocket>(true, child_processes_inherit);
118     break;
119   case ProtocolUdp:
120     socket_up =
121         std::make_unique<UDPSocket>(true, child_processes_inherit);
122     break;
123   case ProtocolUnixDomain:
124 #ifndef LLDB_DISABLE_POSIX
125     socket_up =
126         std::make_unique<DomainSocket>(true, child_processes_inherit);
127 #else
128     error.SetErrorString(
129         "Unix domain sockets are not supported on this platform.");
130 #endif
131     break;
132   case ProtocolUnixAbstract:
133 #ifdef __linux__
134     socket_up =
135         std::make_unique<AbstractSocket>(child_processes_inherit);
136 #else
137     error.SetErrorString(
138         "Abstract domain sockets are not supported on this platform.");
139 #endif
140     break;
141   }
142 
143   if (error.Fail())
144     socket_up.reset();
145 
146   return socket_up;
147 }
148 
149 Status Socket::TcpConnect(llvm::StringRef host_and_port,
150                           bool child_processes_inherit, Socket *&socket) {
151   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_COMMUNICATION));
152   LLDB_LOGF(log, "Socket::%s (host/port = %s)", __FUNCTION__,
153             host_and_port.str().c_str());
154 
155   Status error;
156   std::unique_ptr<Socket> connect_socket(
157       Create(ProtocolTcp, child_processes_inherit, error));
158   if (error.Fail())
159     return error;
160 
161   error = connect_socket->Connect(host_and_port);
162   if (error.Success())
163     socket = connect_socket.release();
164 
165   return error;
166 }
167 
168 Status Socket::TcpListen(llvm::StringRef host_and_port,
169                          bool child_processes_inherit, Socket *&socket,
170                          Predicate<uint16_t> *predicate, int backlog) {
171   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
172   LLDB_LOGF(log, "Socket::%s (%s)", __FUNCTION__, host_and_port.str().c_str());
173 
174   Status error;
175   std::string host_str;
176   std::string port_str;
177   int32_t port = INT32_MIN;
178   if (!DecodeHostAndPort(host_and_port, host_str, port_str, port, &error))
179     return error;
180 
181   std::unique_ptr<TCPSocket> listen_socket(
182       new TCPSocket(true, child_processes_inherit));
183   if (error.Fail())
184     return error;
185 
186   error = listen_socket->Listen(host_and_port, backlog);
187   if (error.Success()) {
188     // We were asked to listen on port zero which means we must now read the
189     // actual port that was given to us as port zero is a special code for
190     // "find an open port for me".
191     if (port == 0)
192       port = listen_socket->GetLocalPortNumber();
193 
194     // Set the port predicate since when doing a listen://<host>:<port> it
195     // often needs to accept the incoming connection which is a blocking system
196     // call. Allowing access to the bound port using a predicate allows us to
197     // wait for the port predicate to be set to a non-zero value from another
198     // thread in an efficient manor.
199     if (predicate)
200       predicate->SetValue(port, eBroadcastAlways);
201     socket = listen_socket.release();
202   }
203 
204   return error;
205 }
206 
207 Status Socket::UdpConnect(llvm::StringRef host_and_port,
208                           bool child_processes_inherit, Socket *&socket) {
209   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
210   LLDB_LOGF(log, "Socket::%s (host/port = %s)", __FUNCTION__,
211             host_and_port.str().c_str());
212 
213   return UDPSocket::Connect(host_and_port, child_processes_inherit, socket);
214 }
215 
216 Status Socket::UnixDomainConnect(llvm::StringRef name,
217                                  bool child_processes_inherit,
218                                  Socket *&socket) {
219   Status error;
220   std::unique_ptr<Socket> connect_socket(
221       Create(ProtocolUnixDomain, child_processes_inherit, error));
222   if (error.Fail())
223     return error;
224 
225   error = connect_socket->Connect(name);
226   if (error.Success())
227     socket = connect_socket.release();
228 
229   return error;
230 }
231 
232 Status Socket::UnixDomainAccept(llvm::StringRef name,
233                                 bool child_processes_inherit, Socket *&socket) {
234   Status error;
235   std::unique_ptr<Socket> listen_socket(
236       Create(ProtocolUnixDomain, child_processes_inherit, error));
237   if (error.Fail())
238     return error;
239 
240   error = listen_socket->Listen(name, 5);
241   if (error.Fail())
242     return error;
243 
244   error = listen_socket->Accept(socket);
245   return error;
246 }
247 
248 Status Socket::UnixAbstractConnect(llvm::StringRef name,
249                                    bool child_processes_inherit,
250                                    Socket *&socket) {
251   Status error;
252   std::unique_ptr<Socket> connect_socket(
253       Create(ProtocolUnixAbstract, child_processes_inherit, error));
254   if (error.Fail())
255     return error;
256 
257   error = connect_socket->Connect(name);
258   if (error.Success())
259     socket = connect_socket.release();
260   return error;
261 }
262 
263 Status Socket::UnixAbstractAccept(llvm::StringRef name,
264                                   bool child_processes_inherit,
265                                   Socket *&socket) {
266   Status error;
267   std::unique_ptr<Socket> listen_socket(
268       Create(ProtocolUnixAbstract, child_processes_inherit, error));
269   if (error.Fail())
270     return error;
271 
272   error = listen_socket->Listen(name, 5);
273   if (error.Fail())
274     return error;
275 
276   error = listen_socket->Accept(socket);
277   return error;
278 }
279 
280 bool Socket::DecodeHostAndPort(llvm::StringRef host_and_port,
281                                std::string &host_str, std::string &port_str,
282                                int32_t &port, Status *error_ptr) {
283   static RegularExpression g_regex(
284       llvm::StringRef("([^:]+|\\[[0-9a-fA-F:]+.*\\]):([0-9]+)"));
285   llvm::SmallVector<llvm::StringRef, 3> matches;
286   if (g_regex.Execute(host_and_port, &matches)) {
287     host_str = matches[1].str();
288     port_str = matches[2].str();
289     // IPv6 addresses are wrapped in [] when specified with ports
290     if (host_str.front() == '[' && host_str.back() == ']')
291       host_str = host_str.substr(1, host_str.size() - 2);
292     bool ok = false;
293     port = StringConvert::ToUInt32(port_str.c_str(), UINT32_MAX, 10, &ok);
294     if (ok && port <= UINT16_MAX) {
295       if (error_ptr)
296         error_ptr->Clear();
297       return true;
298     }
299     // port is too large
300     if (error_ptr)
301       error_ptr->SetErrorStringWithFormat(
302           "invalid host:port specification: '%s'", host_and_port.str().c_str());
303     return false;
304   }
305 
306   // If this was unsuccessful, then check if it's simply a signed 32-bit
307   // integer, representing a port with an empty host.
308   host_str.clear();
309   port_str.clear();
310   if (to_integer(host_and_port, port, 10) && port < UINT16_MAX) {
311     port_str = host_and_port;
312     if (error_ptr)
313       error_ptr->Clear();
314     return true;
315   }
316 
317   if (error_ptr)
318     error_ptr->SetErrorStringWithFormat("invalid host:port specification: '%s'",
319                                         host_and_port.str().c_str());
320   return false;
321 }
322 
323 IOObject::WaitableHandle Socket::GetWaitableHandle() {
324   // TODO: On Windows, use WSAEventSelect
325   return m_socket;
326 }
327 
328 Status Socket::Read(void *buf, size_t &num_bytes) {
329   Status error;
330   int bytes_received = 0;
331   do {
332     bytes_received = ::recv(m_socket, static_cast<char *>(buf), num_bytes, 0);
333   } while (bytes_received < 0 && IsInterrupted());
334 
335   if (bytes_received < 0) {
336     SetLastError(error);
337     num_bytes = 0;
338   } else
339     num_bytes = bytes_received;
340 
341   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_COMMUNICATION));
342   if (log) {
343     LLDB_LOGF(log,
344               "%p Socket::Read() (socket = %" PRIu64
345               ", src = %p, src_len = %" PRIu64 ", flags = 0) => %" PRIi64
346               " (error = %s)",
347               static_cast<void *>(this), static_cast<uint64_t>(m_socket), buf,
348               static_cast<uint64_t>(num_bytes),
349               static_cast<int64_t>(bytes_received), error.AsCString());
350   }
351 
352   return error;
353 }
354 
355 Status Socket::Write(const void *buf, size_t &num_bytes) {
356   const size_t src_len = num_bytes;
357   Status error;
358   int bytes_sent = 0;
359   do {
360     bytes_sent = Send(buf, num_bytes);
361   } while (bytes_sent < 0 && IsInterrupted());
362 
363   if (bytes_sent < 0) {
364     SetLastError(error);
365     num_bytes = 0;
366   } else
367     num_bytes = bytes_sent;
368 
369   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_COMMUNICATION));
370   if (log) {
371     LLDB_LOGF(log,
372               "%p Socket::Write() (socket = %" PRIu64
373               ", src = %p, src_len = %" PRIu64 ", flags = 0) => %" PRIi64
374               " (error = %s)",
375               static_cast<void *>(this), static_cast<uint64_t>(m_socket), buf,
376               static_cast<uint64_t>(src_len),
377               static_cast<int64_t>(bytes_sent), error.AsCString());
378   }
379 
380   return error;
381 }
382 
383 Status Socket::PreDisconnect() {
384   Status error;
385   return error;
386 }
387 
388 Status Socket::Close() {
389   Status error;
390   if (!IsValid() || !m_should_close_fd)
391     return error;
392 
393   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
394   LLDB_LOGF(log, "%p Socket::Close (fd = %" PRIu64 ")",
395             static_cast<void *>(this), static_cast<uint64_t>(m_socket));
396 
397 #if defined(_WIN32)
398   bool success = !!closesocket(m_socket);
399 #else
400   bool success = !!::close(m_socket);
401 #endif
402   // A reference to a FD was passed in, set it to an invalid value
403   m_socket = kInvalidSocketValue;
404   if (!success) {
405     SetLastError(error);
406   }
407 
408   return error;
409 }
410 
411 int Socket::GetOption(int level, int option_name, int &option_value) {
412   get_socket_option_arg_type option_value_p =
413       reinterpret_cast<get_socket_option_arg_type>(&option_value);
414   socklen_t option_value_size = sizeof(int);
415   return ::getsockopt(m_socket, level, option_name, option_value_p,
416                       &option_value_size);
417 }
418 
419 int Socket::SetOption(int level, int option_name, int option_value) {
420   set_socket_option_arg_type option_value_p =
421       reinterpret_cast<get_socket_option_arg_type>(&option_value);
422   return ::setsockopt(m_socket, level, option_name, option_value_p,
423                       sizeof(option_value));
424 }
425 
426 size_t Socket::Send(const void *buf, const size_t num_bytes) {
427   return ::send(m_socket, static_cast<const char *>(buf), num_bytes, 0);
428 }
429 
430 void Socket::SetLastError(Status &error) {
431 #if defined(_WIN32)
432   error.SetError(::WSAGetLastError(), lldb::eErrorTypeWin32);
433 #else
434   error.SetErrorToErrno();
435 #endif
436 }
437 
438 NativeSocket Socket::CreateSocket(const int domain, const int type,
439                                   const int protocol,
440                                   bool child_processes_inherit, Status &error) {
441   error.Clear();
442   auto socket_type = type;
443 #ifdef SOCK_CLOEXEC
444   if (!child_processes_inherit)
445     socket_type |= SOCK_CLOEXEC;
446 #endif
447   auto sock = ::socket(domain, socket_type, protocol);
448   if (sock == kInvalidSocketValue)
449     SetLastError(error);
450 
451   return sock;
452 }
453 
454 NativeSocket Socket::AcceptSocket(NativeSocket sockfd, struct sockaddr *addr,
455                                   socklen_t *addrlen,
456                                   bool child_processes_inherit, Status &error) {
457   error.Clear();
458 #if defined(ANDROID_USE_ACCEPT_WORKAROUND)
459   // Hack:
460   // This enables static linking lldb-server to an API 21 libc, but still
461   // having it run on older devices. It is necessary because API 21 libc's
462   // implementation of accept() uses the accept4 syscall(), which is not
463   // available in older kernels. Using an older libc would fix this issue, but
464   // introduce other ones, as the old libraries were quite buggy.
465   int fd = syscall(__NR_accept, sockfd, addr, addrlen);
466   if (fd >= 0 && !child_processes_inherit) {
467     int flags = ::fcntl(fd, F_GETFD);
468     if (flags != -1 && ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC) != -1)
469       return fd;
470     SetLastError(error);
471     close(fd);
472   }
473   return fd;
474 #elif defined(SOCK_CLOEXEC) && defined(HAVE_ACCEPT4)
475   int flags = 0;
476   if (!child_processes_inherit) {
477     flags |= SOCK_CLOEXEC;
478   }
479   NativeSocket fd = llvm::sys::RetryAfterSignal(-1, ::accept4,
480       sockfd, addr, addrlen, flags);
481 #else
482   NativeSocket fd = llvm::sys::RetryAfterSignal(-1, ::accept,
483       sockfd, addr, addrlen);
484 #endif
485   if (fd == kInvalidSocketValue)
486     SetLastError(error);
487   return fd;
488 }
489