1 //===-- llvm/Support/raw_socket_stream.cpp - Socket streams --*- 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 // This file contains raw_ostream implementations for streams to communicate 10 // via UNIX sockets 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Support/raw_socket_stream.h" 15 #include "llvm/Config/config.h" 16 #include "llvm/Support/Error.h" 17 #include "llvm/Support/FileSystem.h" 18 19 #include <atomic> 20 #include <fcntl.h> 21 #include <thread> 22 23 #ifndef _WIN32 24 #include <poll.h> 25 #include <sys/socket.h> 26 #include <sys/un.h> 27 #else 28 #include "llvm/Support/Windows/WindowsSupport.h" 29 // winsock2.h must be included before afunix.h. Briefly turn off clang-format to 30 // avoid error. 31 // clang-format off 32 #include <winsock2.h> 33 #include <afunix.h> 34 // clang-format on 35 #include <io.h> 36 #endif // _WIN32 37 38 #if defined(HAVE_UNISTD_H) 39 #include <unistd.h> 40 #endif 41 42 using namespace llvm; 43 44 #ifdef _WIN32 45 WSABalancer::WSABalancer() { 46 WSADATA WsaData; 47 ::memset(&WsaData, 0, sizeof(WsaData)); 48 if (WSAStartup(MAKEWORD(2, 2), &WsaData) != 0) { 49 llvm::report_fatal_error("WSAStartup failed"); 50 } 51 } 52 53 WSABalancer::~WSABalancer() { WSACleanup(); } 54 #endif // _WIN32 55 56 static std::error_code getLastSocketErrorCode() { 57 #ifdef _WIN32 58 return std::error_code(::WSAGetLastError(), std::system_category()); 59 #else 60 return errnoAsErrorCode(); 61 #endif 62 } 63 64 static sockaddr_un setSocketAddr(StringRef SocketPath) { 65 struct sockaddr_un Addr; 66 memset(&Addr, 0, sizeof(Addr)); 67 Addr.sun_family = AF_UNIX; 68 strncpy(Addr.sun_path, SocketPath.str().c_str(), sizeof(Addr.sun_path) - 1); 69 return Addr; 70 } 71 72 static Expected<int> getSocketFD(StringRef SocketPath) { 73 #ifdef _WIN32 74 SOCKET Socket = socket(AF_UNIX, SOCK_STREAM, 0); 75 if (Socket == INVALID_SOCKET) { 76 #else 77 int Socket = socket(AF_UNIX, SOCK_STREAM, 0); 78 if (Socket == -1) { 79 #endif // _WIN32 80 return llvm::make_error<StringError>(getLastSocketErrorCode(), 81 "Create socket failed"); 82 } 83 84 struct sockaddr_un Addr = setSocketAddr(SocketPath); 85 if (::connect(Socket, (struct sockaddr *)&Addr, sizeof(Addr)) == -1) 86 return llvm::make_error<StringError>(getLastSocketErrorCode(), 87 "Connect socket failed"); 88 89 #ifdef _WIN32 90 return _open_osfhandle(Socket, 0); 91 #else 92 return Socket; 93 #endif // _WIN32 94 } 95 96 ListeningSocket::ListeningSocket(int SocketFD, StringRef SocketPath, 97 int PipeFD[2]) 98 : FD(SocketFD), SocketPath(SocketPath), PipeFD{PipeFD[0], PipeFD[1]} {} 99 100 ListeningSocket::ListeningSocket(ListeningSocket &&LS) 101 : FD(LS.FD.load()), SocketPath(LS.SocketPath), 102 PipeFD{LS.PipeFD[0], LS.PipeFD[1]} { 103 104 LS.FD = -1; 105 LS.SocketPath.clear(); 106 LS.PipeFD[0] = -1; 107 LS.PipeFD[1] = -1; 108 } 109 110 Expected<ListeningSocket> ListeningSocket::createUnix(StringRef SocketPath, 111 int MaxBacklog) { 112 113 // Handle instances where the target socket address already exists and 114 // differentiate between a preexisting file with and without a bound socket 115 // 116 // ::bind will return std::errc:address_in_use if a file at the socket address 117 // already exists (e.g., the file was not properly unlinked due to a crash) 118 // even if another socket has not yet binded to that address 119 if (llvm::sys::fs::exists(SocketPath)) { 120 Expected<int> MaybeFD = getSocketFD(SocketPath); 121 if (!MaybeFD) { 122 123 // Regardless of the error, notify the caller that a file already exists 124 // at the desired socket address and that there is no bound socket at that 125 // address. The file must be removed before ::bind can use the address 126 consumeError(MaybeFD.takeError()); 127 return llvm::make_error<StringError>( 128 std::make_error_code(std::errc::file_exists), 129 "Socket address unavailable"); 130 } 131 ::close(std::move(*MaybeFD)); 132 133 // Notify caller that the provided socket address already has a bound socket 134 return llvm::make_error<StringError>( 135 std::make_error_code(std::errc::address_in_use), 136 "Socket address unavailable"); 137 } 138 139 #ifdef _WIN32 140 WSABalancer _; 141 SOCKET Socket = socket(AF_UNIX, SOCK_STREAM, 0); 142 if (Socket == INVALID_SOCKET) 143 #else 144 int Socket = socket(AF_UNIX, SOCK_STREAM, 0); 145 if (Socket == -1) 146 #endif 147 return llvm::make_error<StringError>(getLastSocketErrorCode(), 148 "socket create failed"); 149 150 struct sockaddr_un Addr = setSocketAddr(SocketPath); 151 if (::bind(Socket, (struct sockaddr *)&Addr, sizeof(Addr)) == -1) { 152 // Grab error code from call to ::bind before calling ::close 153 std::error_code EC = getLastSocketErrorCode(); 154 ::close(Socket); 155 return llvm::make_error<StringError>(EC, "Bind error"); 156 } 157 158 // Mark socket as passive so incoming connections can be accepted 159 if (::listen(Socket, MaxBacklog) == -1) 160 return llvm::make_error<StringError>(getLastSocketErrorCode(), 161 "Listen error"); 162 163 int PipeFD[2]; 164 #ifdef _WIN32 165 // Reserve 1 byte for the pipe and use default textmode 166 if (::_pipe(PipeFD, 1, 0) == -1) 167 #else 168 if (::pipe(PipeFD) == -1) 169 #endif // _WIN32 170 return llvm::make_error<StringError>(getLastSocketErrorCode(), 171 "pipe failed"); 172 173 #ifdef _WIN32 174 return ListeningSocket{_open_osfhandle(Socket, 0), SocketPath, PipeFD}; 175 #else 176 return ListeningSocket{Socket, SocketPath, PipeFD}; 177 #endif // _WIN32 178 } 179 180 Expected<std::unique_ptr<raw_socket_stream>> 181 ListeningSocket::accept(std::chrono::milliseconds Timeout) { 182 183 struct pollfd FDs[2]; 184 FDs[0].events = POLLIN; 185 #ifdef _WIN32 186 SOCKET WinServerSock = _get_osfhandle(FD); 187 FDs[0].fd = WinServerSock; 188 #else 189 FDs[0].fd = FD; 190 #endif 191 FDs[1].events = POLLIN; 192 FDs[1].fd = PipeFD[0]; 193 194 // Keep track of how much time has passed in case poll is interupted by a 195 // signal and needs to be recalled 196 int RemainingTime = Timeout.count(); 197 std::chrono::milliseconds ElapsedTime = std::chrono::milliseconds(0); 198 int PollStatus = -1; 199 200 while (PollStatus == -1 && (Timeout.count() == -1 || ElapsedTime < Timeout)) { 201 if (Timeout.count() != -1) 202 RemainingTime -= ElapsedTime.count(); 203 204 auto Start = std::chrono::steady_clock::now(); 205 #ifdef _WIN32 206 PollStatus = WSAPoll(FDs, 2, RemainingTime); 207 #else 208 PollStatus = ::poll(FDs, 2, RemainingTime); 209 #endif 210 // If FD equals -1 then ListeningSocket::shutdown has been called and it is 211 // appropriate to return operation_canceled 212 if (FD.load() == -1) 213 return llvm::make_error<StringError>( 214 std::make_error_code(std::errc::operation_canceled), 215 "Accept canceled"); 216 217 #if _WIN32 218 if (PollStatus == SOCKET_ERROR) { 219 #else 220 if (PollStatus == -1) { 221 #endif 222 std::error_code PollErrCode = getLastSocketErrorCode(); 223 // Ignore EINTR (signal occured before any request event) and retry 224 if (PollErrCode != std::errc::interrupted) 225 return llvm::make_error<StringError>(PollErrCode, "FD poll failed"); 226 } 227 if (PollStatus == 0) 228 return llvm::make_error<StringError>( 229 std::make_error_code(std::errc::timed_out), 230 "No client requests within timeout window"); 231 232 if (FDs[0].revents & POLLNVAL) 233 return llvm::make_error<StringError>( 234 std::make_error_code(std::errc::bad_file_descriptor)); 235 236 auto Stop = std::chrono::steady_clock::now(); 237 ElapsedTime += 238 std::chrono::duration_cast<std::chrono::milliseconds>(Stop - Start); 239 } 240 241 int AcceptFD; 242 #ifdef _WIN32 243 SOCKET WinAcceptSock = ::accept(WinServerSock, NULL, NULL); 244 AcceptFD = _open_osfhandle(WinAcceptSock, 0); 245 #else 246 AcceptFD = ::accept(FD, NULL, NULL); 247 #endif 248 249 if (AcceptFD == -1) 250 return llvm::make_error<StringError>(getLastSocketErrorCode(), 251 "Socket accept failed"); 252 return std::make_unique<raw_socket_stream>(AcceptFD); 253 } 254 255 void ListeningSocket::shutdown() { 256 int ObservedFD = FD.load(); 257 258 if (ObservedFD == -1) 259 return; 260 261 // If FD equals ObservedFD set FD to -1; If FD doesn't equal ObservedFD then 262 // another thread is responsible for shutdown so return 263 if (!FD.compare_exchange_strong(ObservedFD, -1)) 264 return; 265 266 ::close(ObservedFD); 267 ::unlink(SocketPath.c_str()); 268 269 // Ensure ::poll returns if shutdown is called by a seperate thread 270 char Byte = 'A'; 271 ssize_t written = ::write(PipeFD[1], &Byte, 1); 272 273 // Ignore any write() error 274 (void)written; 275 } 276 277 ListeningSocket::~ListeningSocket() { 278 shutdown(); 279 280 // Close the pipe's FDs in the destructor instead of within 281 // ListeningSocket::shutdown to avoid unnecessary synchronization issues that 282 // would occur as PipeFD's values would have to be changed to -1 283 // 284 // The move constructor sets PipeFD to -1 285 if (PipeFD[0] != -1) 286 ::close(PipeFD[0]); 287 if (PipeFD[1] != -1) 288 ::close(PipeFD[1]); 289 } 290 291 //===----------------------------------------------------------------------===// 292 // raw_socket_stream 293 //===----------------------------------------------------------------------===// 294 295 raw_socket_stream::raw_socket_stream(int SocketFD) 296 : raw_fd_stream(SocketFD, true) {} 297 298 Expected<std::unique_ptr<raw_socket_stream>> 299 raw_socket_stream::createConnectedUnix(StringRef SocketPath) { 300 #ifdef _WIN32 301 WSABalancer _; 302 #endif // _WIN32 303 Expected<int> FD = getSocketFD(SocketPath); 304 if (!FD) 305 return FD.takeError(); 306 return std::make_unique<raw_socket_stream>(*FD); 307 } 308 309 raw_socket_stream::~raw_socket_stream() {} 310