Alex Vakulenko | e4eec20 | 2017-01-27 14:41:04 -0800 | [diff] [blame^] | 1 | #include "uds/ipc_helper.h" |
| 2 | |
| 3 | #include <alloca.h> |
| 4 | #include <errno.h> |
| 5 | #include <log/log.h> |
| 6 | #include <poll.h> |
| 7 | #include <string.h> |
| 8 | #include <sys/inotify.h> |
| 9 | #include <sys/param.h> |
| 10 | #include <sys/socket.h> |
| 11 | |
| 12 | #include <algorithm> |
| 13 | |
| 14 | #include <pdx/service.h> |
| 15 | #include <pdx/utility.h> |
| 16 | |
| 17 | namespace android { |
| 18 | namespace pdx { |
| 19 | namespace uds { |
| 20 | |
| 21 | uint32_t kMagicPreamble = 0x7564736d; // 'udsm'. |
| 22 | |
| 23 | struct MessagePreamble { |
| 24 | uint32_t magic{0}; |
| 25 | uint32_t data_size{0}; |
| 26 | uint32_t fd_count{0}; |
| 27 | }; |
| 28 | |
| 29 | Status<void> SendPayload::Send(int socket_fd) { |
| 30 | return Send(socket_fd, nullptr); |
| 31 | } |
| 32 | |
| 33 | Status<void> SendPayload::Send(int socket_fd, const ucred* cred) { |
| 34 | MessagePreamble preamble; |
| 35 | preamble.magic = kMagicPreamble; |
| 36 | preamble.data_size = buffer_.size(); |
| 37 | preamble.fd_count = file_handles_.size(); |
| 38 | |
| 39 | ssize_t ret = |
| 40 | RETRY_EINTR(send(socket_fd, &preamble, sizeof(preamble), MSG_NOSIGNAL)); |
| 41 | if (ret < 0) |
| 42 | return ErrorStatus(errno); |
| 43 | if (ret != sizeof(preamble)) |
| 44 | return ErrorStatus(EIO); |
| 45 | |
| 46 | msghdr msg = {}; |
| 47 | iovec recv_vect = {buffer_.data(), buffer_.size()}; |
| 48 | msg.msg_iov = &recv_vect; |
| 49 | msg.msg_iovlen = 1; |
| 50 | |
| 51 | if (cred || !file_handles_.empty()) { |
| 52 | const size_t fd_bytes = file_handles_.size() * sizeof(int); |
| 53 | msg.msg_controllen = (cred ? CMSG_SPACE(sizeof(ucred)) : 0) + |
| 54 | (fd_bytes == 0 ? 0 : CMSG_SPACE(fd_bytes)); |
| 55 | msg.msg_control = alloca(msg.msg_controllen); |
| 56 | |
| 57 | cmsghdr* control = CMSG_FIRSTHDR(&msg); |
| 58 | if (cred) { |
| 59 | control->cmsg_level = SOL_SOCKET; |
| 60 | control->cmsg_type = SCM_CREDENTIALS; |
| 61 | control->cmsg_len = CMSG_LEN(sizeof(ucred)); |
| 62 | memcpy(CMSG_DATA(control), cred, sizeof(ucred)); |
| 63 | control = CMSG_NXTHDR(&msg, control); |
| 64 | } |
| 65 | |
| 66 | if (fd_bytes) { |
| 67 | control->cmsg_level = SOL_SOCKET; |
| 68 | control->cmsg_type = SCM_RIGHTS; |
| 69 | control->cmsg_len = CMSG_LEN(fd_bytes); |
| 70 | memcpy(CMSG_DATA(control), file_handles_.data(), fd_bytes); |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | ret = RETRY_EINTR(sendmsg(socket_fd, &msg, MSG_NOSIGNAL)); |
| 75 | if (ret < 0) |
| 76 | return ErrorStatus(errno); |
| 77 | if (static_cast<size_t>(ret) != buffer_.size()) |
| 78 | return ErrorStatus(EIO); |
| 79 | return {}; |
| 80 | } |
| 81 | |
| 82 | // MessageWriter |
| 83 | void* SendPayload::GetNextWriteBufferSection(size_t size) { |
| 84 | return buffer_.grow_by(size); |
| 85 | } |
| 86 | |
| 87 | OutputResourceMapper* SendPayload::GetOutputResourceMapper() { return this; } |
| 88 | |
| 89 | // OutputResourceMapper |
| 90 | FileReference SendPayload::PushFileHandle(const LocalHandle& handle) { |
| 91 | if (handle) { |
| 92 | const int ref = file_handles_.size(); |
| 93 | file_handles_.push_back(handle.Get()); |
| 94 | return ref; |
| 95 | } else { |
| 96 | return handle.Get(); |
| 97 | } |
| 98 | } |
| 99 | |
| 100 | FileReference SendPayload::PushFileHandle(const BorrowedHandle& handle) { |
| 101 | if (handle) { |
| 102 | const int ref = file_handles_.size(); |
| 103 | file_handles_.push_back(handle.Get()); |
| 104 | return ref; |
| 105 | } else { |
| 106 | return handle.Get(); |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | FileReference SendPayload::PushFileHandle(const RemoteHandle& handle) { |
| 111 | return handle.Get(); |
| 112 | } |
| 113 | |
| 114 | ChannelReference SendPayload::PushChannelHandle( |
| 115 | const LocalChannelHandle& /*handle*/) { |
| 116 | return -1; |
| 117 | } |
| 118 | ChannelReference SendPayload::PushChannelHandle( |
| 119 | const BorrowedChannelHandle& /*handle*/) { |
| 120 | return -1; |
| 121 | } |
| 122 | ChannelReference SendPayload::PushChannelHandle( |
| 123 | const RemoteChannelHandle& /*handle*/) { |
| 124 | return -1; |
| 125 | } |
| 126 | |
| 127 | Status<void> ReceivePayload::Receive(int socket_fd) { |
| 128 | return Receive(socket_fd, nullptr); |
| 129 | } |
| 130 | |
| 131 | Status<void> ReceivePayload::Receive(int socket_fd, ucred* cred) { |
| 132 | MessagePreamble preamble; |
| 133 | ssize_t ret = |
| 134 | RETRY_EINTR(recv(socket_fd, &preamble, sizeof(preamble), MSG_WAITALL)); |
| 135 | if (ret < 0) |
| 136 | return ErrorStatus(errno); |
| 137 | if (ret != sizeof(preamble) || preamble.magic != kMagicPreamble) |
| 138 | return ErrorStatus(EIO); |
| 139 | |
| 140 | buffer_.resize(preamble.data_size); |
| 141 | file_handles_.clear(); |
| 142 | read_pos_ = 0; |
| 143 | |
| 144 | msghdr msg = {}; |
| 145 | iovec recv_vect = {buffer_.data(), buffer_.size()}; |
| 146 | msg.msg_iov = &recv_vect; |
| 147 | msg.msg_iovlen = 1; |
| 148 | |
| 149 | if (cred || preamble.fd_count) { |
| 150 | const size_t receive_fd_bytes = preamble.fd_count * sizeof(int); |
| 151 | msg.msg_controllen = |
| 152 | (cred ? CMSG_SPACE(sizeof(ucred)) : 0) + |
| 153 | (receive_fd_bytes == 0 ? 0 : CMSG_SPACE(receive_fd_bytes)); |
| 154 | msg.msg_control = alloca(msg.msg_controllen); |
| 155 | } |
| 156 | |
| 157 | ret = RETRY_EINTR(recvmsg(socket_fd, &msg, MSG_WAITALL)); |
| 158 | if (ret < 0) |
| 159 | return ErrorStatus(errno); |
| 160 | if (static_cast<uint32_t>(ret) != preamble.data_size) |
| 161 | return ErrorStatus(EIO); |
| 162 | |
| 163 | bool cred_available = false; |
| 164 | file_handles_.reserve(preamble.fd_count); |
| 165 | cmsghdr* cmsg = CMSG_FIRSTHDR(&msg); |
| 166 | while (cmsg) { |
| 167 | if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_CREDENTIALS && |
| 168 | cred && cmsg->cmsg_len == CMSG_LEN(sizeof(ucred))) { |
| 169 | cred_available = true; |
| 170 | memcpy(cred, CMSG_DATA(cmsg), sizeof(ucred)); |
| 171 | } else if (cmsg->cmsg_level == SOL_SOCKET && |
| 172 | cmsg->cmsg_type == SCM_RIGHTS) { |
| 173 | socklen_t payload_len = cmsg->cmsg_len - CMSG_LEN(0); |
| 174 | const int* fds = reinterpret_cast<const int*>(CMSG_DATA(cmsg)); |
| 175 | size_t fd_count = payload_len / sizeof(int); |
| 176 | std::transform(fds, fds + fd_count, std::back_inserter(file_handles_), |
| 177 | [](int fd) { return LocalHandle{fd}; }); |
| 178 | } |
| 179 | cmsg = CMSG_NXTHDR(&msg, cmsg); |
| 180 | } |
| 181 | |
| 182 | if (cred && !cred_available) { |
| 183 | return ErrorStatus(EIO); |
| 184 | } |
| 185 | |
| 186 | return {}; |
| 187 | } |
| 188 | |
| 189 | // MessageReader |
| 190 | MessageReader::BufferSection ReceivePayload::GetNextReadBufferSection() { |
| 191 | return {buffer_.data() + read_pos_, &*buffer_.end()}; |
| 192 | } |
| 193 | |
| 194 | void ReceivePayload::ConsumeReadBufferSectionData(const void* new_start) { |
| 195 | read_pos_ = PointerDistance(new_start, buffer_.data()); |
| 196 | } |
| 197 | |
| 198 | InputResourceMapper* ReceivePayload::GetInputResourceMapper() { return this; } |
| 199 | |
| 200 | // InputResourceMapper |
| 201 | bool ReceivePayload::GetFileHandle(FileReference ref, LocalHandle* handle) { |
| 202 | if (ref < 0) { |
| 203 | *handle = LocalHandle{ref}; |
| 204 | return true; |
| 205 | } |
| 206 | if (static_cast<size_t>(ref) > file_handles_.size()) |
| 207 | return false; |
| 208 | *handle = std::move(file_handles_[ref]); |
| 209 | return true; |
| 210 | } |
| 211 | |
| 212 | bool ReceivePayload::GetChannelHandle(ChannelReference /*ref*/, |
| 213 | LocalChannelHandle* /*handle*/) { |
| 214 | return false; |
| 215 | } |
| 216 | |
| 217 | Status<void> SendData(int socket_fd, const void* data, size_t size) { |
| 218 | ssize_t size_written = RETRY_EINTR(send(socket_fd, data, size, MSG_NOSIGNAL)); |
| 219 | if (size_written < 0) |
| 220 | return ErrorStatus(errno); |
| 221 | if (static_cast<size_t>(size_written) != size) |
| 222 | return ErrorStatus(EIO); |
| 223 | return {}; |
| 224 | } |
| 225 | |
| 226 | Status<void> SendDataVector(int socket_fd, const iovec* data, size_t count) { |
| 227 | msghdr msg = {}; |
| 228 | msg.msg_iov = const_cast<iovec*>(data); |
| 229 | msg.msg_iovlen = count; |
| 230 | ssize_t size_written = RETRY_EINTR(sendmsg(socket_fd, &msg, MSG_NOSIGNAL)); |
| 231 | if (size_written < 0) |
| 232 | return ErrorStatus(errno); |
| 233 | if (static_cast<size_t>(size_written) != CountVectorSize(data, count)) |
| 234 | return ErrorStatus(EIO); |
| 235 | return {}; |
| 236 | } |
| 237 | |
| 238 | Status<void> ReceiveData(int socket_fd, void* data, size_t size) { |
| 239 | ssize_t size_read = RETRY_EINTR(recv(socket_fd, data, size, MSG_WAITALL)); |
| 240 | if (size_read < 0) |
| 241 | return ErrorStatus(errno); |
| 242 | if (static_cast<size_t>(size_read) != size) |
| 243 | return ErrorStatus(EIO); |
| 244 | return {}; |
| 245 | } |
| 246 | |
| 247 | Status<void> ReceiveDataVector(int socket_fd, const iovec* data, size_t count) { |
| 248 | msghdr msg = {}; |
| 249 | msg.msg_iov = const_cast<iovec*>(data); |
| 250 | msg.msg_iovlen = count; |
| 251 | ssize_t size_read = RETRY_EINTR(recvmsg(socket_fd, &msg, MSG_WAITALL)); |
| 252 | if (size_read < 0) |
| 253 | return ErrorStatus(errno); |
| 254 | if (static_cast<size_t>(size_read) != CountVectorSize(data, count)) |
| 255 | return ErrorStatus(EIO); |
| 256 | return {}; |
| 257 | } |
| 258 | |
| 259 | size_t CountVectorSize(const iovec* vector, size_t count) { |
| 260 | return std::accumulate( |
| 261 | vector, vector + count, size_t{0}, |
| 262 | [](size_t size, const iovec& vec) { return size + vec.iov_len; }); |
| 263 | } |
| 264 | |
| 265 | void InitRequest(android::pdx::uds::RequestHeader<BorrowedHandle>* request, |
| 266 | int opcode, uint32_t send_len, uint32_t max_recv_len, |
| 267 | bool is_impulse) { |
| 268 | request->op = opcode; |
| 269 | request->cred.pid = getpid(); |
| 270 | request->cred.uid = geteuid(); |
| 271 | request->cred.gid = getegid(); |
| 272 | request->send_len = send_len; |
| 273 | request->max_recv_len = max_recv_len; |
| 274 | request->is_impulse = is_impulse; |
| 275 | } |
| 276 | |
| 277 | Status<void> WaitForEndpoint(const std::string& endpoint_path, |
| 278 | int64_t timeout_ms) { |
| 279 | // Endpoint path must be absolute. |
| 280 | if (endpoint_path.empty() || endpoint_path.front() != '/') |
| 281 | return ErrorStatus(EINVAL); |
| 282 | |
| 283 | // Create inotify fd. |
| 284 | LocalHandle fd{inotify_init()}; |
| 285 | if (!fd) |
| 286 | return ErrorStatus(errno); |
| 287 | |
| 288 | // Set the inotify fd to non-blocking. |
| 289 | int ret = fcntl(fd.Get(), F_GETFL); |
| 290 | fcntl(fd.Get(), F_SETFL, ret | O_NONBLOCK); |
| 291 | |
| 292 | // Setup the pollfd. |
| 293 | pollfd pfd = {fd.Get(), POLLIN, 0}; |
| 294 | |
| 295 | // Find locations of each path separator. |
| 296 | std::vector<size_t> separators{0}; // The path is absolute, so '/' is at #0. |
| 297 | size_t pos = endpoint_path.find('/', 1); |
| 298 | while (pos != std::string::npos) { |
| 299 | separators.push_back(pos); |
| 300 | pos = endpoint_path.find('/', pos + 1); |
| 301 | } |
| 302 | separators.push_back(endpoint_path.size()); |
| 303 | |
| 304 | // Walk down the path, checking for existence and waiting if needed. |
| 305 | pos = 1; |
| 306 | size_t links = 0; |
| 307 | std::string current; |
| 308 | while (pos < separators.size() && links <= MAXSYMLINKS) { |
| 309 | std::string previous = current; |
| 310 | current = endpoint_path.substr(0, separators[pos]); |
| 311 | |
| 312 | // Check for existence; proceed to setup a watch if not. |
| 313 | if (access(current.c_str(), F_OK) < 0) { |
| 314 | if (errno != ENOENT) |
| 315 | return ErrorStatus(errno); |
| 316 | |
| 317 | // Extract the name of the path component to wait for. |
| 318 | std::string next = current.substr( |
| 319 | separators[pos - 1] + 1, separators[pos] - separators[pos - 1] - 1); |
| 320 | |
| 321 | // Add a watch on the last existing directory we reach. |
| 322 | int wd = inotify_add_watch( |
| 323 | fd.Get(), previous.c_str(), |
| 324 | IN_CREATE | IN_DELETE_SELF | IN_MOVE_SELF | IN_MOVED_TO); |
| 325 | if (wd < 0) { |
| 326 | if (errno != ENOENT) |
| 327 | return ErrorStatus(errno); |
| 328 | // Restart at the beginning if previous was deleted. |
| 329 | links = 0; |
| 330 | current.clear(); |
| 331 | pos = 1; |
| 332 | continue; |
| 333 | } |
| 334 | |
| 335 | // Make sure current didn't get created before the watch was added. |
| 336 | ret = access(current.c_str(), F_OK); |
| 337 | if (ret < 0) { |
| 338 | if (errno != ENOENT) |
| 339 | return ErrorStatus(errno); |
| 340 | |
| 341 | bool exit_poll = false; |
| 342 | while (!exit_poll) { |
| 343 | // Wait for an event or timeout. |
| 344 | ret = poll(&pfd, 1, timeout_ms); |
| 345 | if (ret <= 0) |
| 346 | return ErrorStatus(ret == 0 ? ETIMEDOUT : errno); |
| 347 | |
| 348 | // Read events. |
| 349 | char buffer[sizeof(inotify_event) + NAME_MAX + 1]; |
| 350 | |
| 351 | ret = read(fd.Get(), buffer, sizeof(buffer)); |
| 352 | if (ret < 0) { |
| 353 | if (errno == EAGAIN || errno == EWOULDBLOCK) |
| 354 | continue; |
| 355 | else |
| 356 | return ErrorStatus(errno); |
| 357 | } else if (static_cast<size_t>(ret) < sizeof(struct inotify_event)) { |
| 358 | return ErrorStatus(EIO); |
| 359 | } |
| 360 | |
| 361 | auto* event = reinterpret_cast<const inotify_event*>(buffer); |
| 362 | auto* end = reinterpret_cast<const inotify_event*>(buffer + ret); |
| 363 | while (event < end) { |
| 364 | std::string event_for; |
| 365 | if (event->len > 0) |
| 366 | event_for = event->name; |
| 367 | |
| 368 | if (event->mask & (IN_CREATE | IN_MOVED_TO)) { |
| 369 | // See if this is the droid we're looking for. |
| 370 | if (next == event_for) { |
| 371 | exit_poll = true; |
| 372 | break; |
| 373 | } |
| 374 | } else if (event->mask & (IN_DELETE_SELF | IN_MOVE_SELF)) { |
| 375 | // Restart at the beginning if our watch dir is deleted. |
| 376 | links = 0; |
| 377 | current.clear(); |
| 378 | pos = 0; |
| 379 | exit_poll = true; |
| 380 | break; |
| 381 | } |
| 382 | |
| 383 | event = reinterpret_cast<const inotify_event*>(AdvancePointer( |
| 384 | event, sizeof(struct inotify_event) + event->len)); |
| 385 | } // while (event < end) |
| 386 | } // while (!exit_poll) |
| 387 | } // Current dir doesn't exist. |
| 388 | ret = inotify_rm_watch(fd.Get(), wd); |
| 389 | if (ret < 0 && errno != EINVAL) |
| 390 | return ErrorStatus(errno); |
| 391 | } // if (access(current.c_str(), F_OK) < 0) |
| 392 | |
| 393 | // Check for symbolic link and update link count. |
| 394 | struct stat stat_buf; |
| 395 | ret = lstat(current.c_str(), &stat_buf); |
| 396 | if (ret < 0 && errno != ENOENT) |
| 397 | return ErrorStatus(errno); |
| 398 | else if (ret == 0 && S_ISLNK(stat_buf.st_mode)) |
| 399 | links++; |
| 400 | pos++; |
| 401 | } // while (pos < separators.size() && links <= MAXSYMLINKS) |
| 402 | |
| 403 | return {}; |
| 404 | } |
| 405 | |
| 406 | } // namespace uds |
| 407 | } // namespace pdx |
| 408 | } // namespace android |