| 1 | /*++ |
| 2 | |
| 3 | Copyright (c) Microsoft. All rights reserved. |
| 4 | |
| 5 | Module Name: |
| 6 | |
| 7 | drvfs.c |
| 8 | |
| 9 | Abstract: |
| 10 | |
| 11 | This file contains DrvFs function definitions. |
| 12 | |
| 13 | --*/ |
| 14 | |
| 15 | #include "common.h" |
| 16 | #include <sys/mount.h> |
| 17 | #include <sys/stat.h> |
| 18 | #include <stdarg.h> |
| 19 | #include <mountutilcpp.h> |
| 20 | #include "util.h" |
| 21 | #include "drvfs.h" |
| 22 | #include "config.h" |
| 23 | #include "message.h" |
| 24 | #include <cassert> |
| 25 | #include <filesystem> |
| 26 | #include <mutex> |
| 27 | #include <optional> |
| 28 | #include <thread> |
| 29 | |
| 30 | using namespace std::chrono_literals; |
| 31 | |
| 32 | #define PLAN9_CASE_OPTION "case=" |
| 33 | #define PLAN9_CASE_OPTION_DIR PLAN9_CASE_OPTION "dir" |
| 34 | #define PLAN9_CASE_OPTION_FORCE PLAN9_CASE_OPTION "force" |
| 35 | #define PLAN9_CASE_OPTION_OFF PLAN9_CASE_OPTION "off" |
| 36 | #define PLAN9_SYMLINK_ROOT_OPTION "symlinkroot=" |
| 37 | #define PLAN9_UNC_PREFIX_LENGTH (2) |
| 38 | |
| 39 | #define VIRTIOFS_TAG_DIR "/run/wsl/virtiofs" |
| 40 | |
| 41 | #define LOG_STDERR(_errno) fprintf(stderr, "mount: %s\n", strerror(_errno)) |
| 42 | |
| 43 | constexpr int c_exitCodeInvalidUsage = 1; |
| 44 | constexpr int c_exitCodeMountFail = 32; |
| 45 | |
| 46 | int MountFilesystem(const char* FsType, const char* Source, const char* Target, const char* Options, int* ExitCode = nullptr); |
| 47 | |
| 48 | int MountWithRetry(const char* Source, const char* Target, const char* FsType, const char* Options, int* ExitCode = nullptr); |
| 49 | |
| 50 | std::optional<VirtioFsMountRoot> ParseAggregateVirtioFsMountRoot(std::string_view Tag, std::string_view Root) |
| 51 | { |
| 52 | if ((Tag != LX_INIT_DRVFS_VIRTIO_TAG && Tag != LX_INIT_DRVFS_ADMIN_VIRTIO_TAG) || Root.size() < 2 || Root.front() != '/') |
| 53 | { |
| 54 | return {}; |
| 55 | } |
| 56 | |
| 57 | Root.remove_prefix(1); |
| 58 | const auto separator = Root.find('/'); |
| 59 | const auto childName = Root.substr(0, separator); |
| 60 | if (!wsl::shared::string::ToGuid(childName)) |
| 61 | { |
| 62 | return {}; |
| 63 | } |
| 64 | |
| 65 | const auto subPath = separator == std::string_view::npos ? std::string_view{"/"} : Root.substr(separator); |
| 66 | return VirtioFsMountRoot{childName, subPath}; |
| 67 | } |
| 68 | |
| 69 | namespace { |
| 70 | std::mutex g_virtiofsDeviceMutex; |
| 71 | |
| 72 | bool IsMountPoint(const std::string& Path) |
| 73 | { |
| 74 | struct stat self = {}; |
| 75 | struct stat parent = {}; |
| 76 | if (stat(Path.c_str(), &self) != 0) |
| 77 | { |
| 78 | return false; |
| 79 | } |
| 80 | |
| 81 | const auto parentPath = Path + "/.."; |
| 82 | if (stat(parentPath.c_str(), &parent) != 0) |
| 83 | { |
| 84 | return false; |
| 85 | } |
| 86 | |
| 87 | return self.st_dev != parent.st_dev; |
| 88 | } |
| 89 | } // namespace |
| 90 | |
| 91 | int MountVirtioFsChild(const char* Tag, const char* ChildName, const char* Target, const char* Options, int* ExitCode, std::string_view SubPath) |
| 92 | { |
| 93 | if ((strcmp(Tag, LX_INIT_DRVFS_VIRTIO_TAG) != 0 && strcmp(Tag, LX_INIT_DRVFS_ADMIN_VIRTIO_TAG) != 0) || |
| 94 | !wsl::shared::string::ToGuid(ChildName) || SubPath.empty() || SubPath.front() != '/') |
| 95 | { |
| 96 | errno = EINVAL; |
| 97 | return -1; |
| 98 | } |
| 99 | |
| 100 | const auto rootTarget = std::format("{}/{}", VIRTIOFS_MOUNT_DIR, Tag); |
| 101 | const auto childSource = std::format("{}/{}{}", rootTarget, ChildName, SubPath == "/" ? std::string_view{} : SubPath); |
| 102 | { |
| 103 | std::lock_guard<std::mutex> lock(g_virtiofsDeviceMutex); |
| 104 | if (!IsMountPoint(rootTarget)) |
| 105 | { |
| 106 | if (UtilMkdirPath(rootTarget.c_str(), 0755) < 0) |
| 107 | { |
| 108 | return -1; |
| 109 | } |
| 110 | |
| 111 | if (MountWithRetry(Tag, rootTarget.c_str(), VIRTIO_FS_TYPE, "", ExitCode) < 0 && !IsMountPoint(rootTarget)) |
| 112 | { |
| 113 | return -1; |
| 114 | } |
| 115 | } |
| 116 | } |
| 117 | |
| 118 | if (UtilMkdirPath(Target, 0755) < 0) |
| 119 | { |
| 120 | return -1; |
| 121 | } |
| 122 | |
| 123 | constexpr int c_maxAttempts = 5; |
| 124 | int lastError = 0; |
| 125 | for (int attempt = 0; attempt < c_maxAttempts; ++attempt) |
| 126 | { |
| 127 | if (mount(childSource.c_str(), Target, nullptr, MS_BIND, nullptr) == 0) |
| 128 | { |
| 129 | lastError = 0; |
| 130 | break; |
| 131 | } |
| 132 | |
| 133 | lastError = errno; |
| 134 | if (lastError != ENOENT) |
| 135 | { |
| 136 | break; |
| 137 | } |
| 138 | |
| 139 | std::this_thread::sleep_for(std::chrono::milliseconds{50}); |
| 140 | } |
| 141 | |
| 142 | if (lastError != 0) |
| 143 | { |
| 144 | errno = lastError; |
| 145 | if (ExitCode != nullptr) |
| 146 | { |
| 147 | *ExitCode = c_exitCodeMountFail; |
| 148 | } |
| 149 | |
| 150 | return -1; |
| 151 | } |
| 152 | |
| 153 | const auto parsed = mountutil::MountParseFlags(Options ? Options : ""); |
| 154 | auto bindFlags = parsed.MountFlags; |
| 155 | if ((bindFlags & (MS_NOATIME | MS_STRICTATIME)) == 0) |
| 156 | { |
| 157 | bindFlags |= MS_RELATIME; |
| 158 | } |
| 159 | |
| 160 | if (mount(nullptr, Target, nullptr, MS_BIND | MS_REMOUNT | bindFlags, parsed.StringOptions.c_str()) < 0) |
| 161 | { |
| 162 | const auto savedError = errno; |
| 163 | // Remove the successful bind before MountVirtioFs falls back to Plan 9. |
| 164 | umount2(Target, MNT_DETACH); |
| 165 | errno = savedError; |
| 166 | if (ExitCode != nullptr) |
| 167 | { |
| 168 | *ExitCode = c_exitCodeMountFail; |
| 169 | } |
| 170 | |
| 171 | return -1; |
| 172 | } |
| 173 | |
| 174 | if (ExitCode != nullptr) |
| 175 | { |
| 176 | *ExitCode = 0; |
| 177 | } |
| 178 | |
| 179 | return 0; |
| 180 | } |
| 181 | |
| 182 | void SaveVirtiofsTagMapping(const char* Tag, const char* Source) |
| 183 | |
| 184 | /*++ |
| 185 | |
| 186 | Routine Description: |
| 187 | |
| 188 | This routine creates a symlink in VIRTIOFS_TAG_DIR that maps a virtiofs tag |
| 189 | to its Windows mount source path. This allows QueryVirtiofsMountSource to |
| 190 | resolve tags without talking to the service. |
| 191 | |
| 192 | Arguments: |
| 193 | |
| 194 | Tag - Supplies the virtiofs tag. |
| 195 | |
| 196 | Source - Supplies the Windows path the tag refers to. |
| 197 | |
| 198 | Return Value: |
| 199 | |
| 200 | None. |
| 201 | |
| 202 | --*/ |
| 203 | |
| 204 | { |
| 205 | // |
| 206 | // Validate the tag is a GUID to prevent path traversal. |
| 207 | // |
| 208 | |
| 209 | const auto Guid = wsl::shared::string::ToGuid(Tag); |
| 210 | if (!Guid) |
| 211 | { |
| 212 | LOG_WARNING("Invalid virtiofs tag {}", Tag); |
| 213 | return; |
| 214 | } |
| 215 | |
| 216 | // |
| 217 | // Canonicalize path separators to backslashes before persisting. |
| 218 | // |
| 219 | |
| 220 | std::string CanonicalSource{Source}; |
| 221 | UtilCanonicalisePathSeparator(CanonicalSource, PATH_SEP_NT); |
| 222 | |
| 223 | UtilMkdirPath(VIRTIOFS_TAG_DIR, 0755); |
| 224 | |
| 225 | auto LinkPath = std::format("{}/{}", VIRTIOFS_TAG_DIR, Tag); |
| 226 | |
| 227 | // |
| 228 | // Remove any existing symlink for this tag before creating a new one. |
| 229 | // |
| 230 | |
| 231 | unlink(LinkPath.c_str()); |
| 232 | if (symlink(CanonicalSource.c_str(), LinkPath.c_str()) < 0) |
| 233 | { |
| 234 | LOG_WARNING("Failed to create virtiofs tag symlink {} -> {}: {}", LinkPath, CanonicalSource, errno); |
| 235 | } |
| 236 | } |
| 237 | |
| 238 | std::pair<std::string, std::string> ConvertDrvfsMountOptionsToPlan9(std::string_view Options, const wsl::linux::WslDistributionConfig& Config) |
| 239 | |
| 240 | /*++ |
| 241 | |
| 242 | Routine Description: |
| 243 | |
| 244 | This routine converts each applicable DrvFs mount option into a 9p mount option and splits |
| 245 | non-DrvFs options to a different list. |
| 246 | |
| 247 | Arguments: |
| 248 | |
| 249 | Options - Supplies the DrvFs mount options. |
| 250 | |
| 251 | Config - Supplies the distribution configuration. |
| 252 | |
| 253 | Return Value: |
| 254 | |
| 255 | A pair representing the 9p mount options, and standard mount options. |
| 256 | |
| 257 | --*/ |
| 258 | |
| 259 | { |
| 260 | using wsl::shared::string::StartsWith; |
| 261 | |
| 262 | std::string Plan9Options{}; |
| 263 | std::string StandardOptions{}; |
| 264 | while (!Options.empty()) |
| 265 | { |
| 266 | auto Option = UtilStringNextToken(Options, ","); |
| 267 | if ((Option == "metadata") || (StartsWith(Option, PLAN9_CASE_OPTION)) || (StartsWith(Option, "uid=")) || |
| 268 | (StartsWith(Option, "gid=")) || (StartsWith(Option, "umask=")) || (StartsWith(Option, "dmask=")) || |
| 269 | (StartsWith(Option, "fmask=")) || (StartsWith(Option, PLAN9_SYMLINK_ROOT_OPTION))) |
| 270 | { |
| 271 | if (Option == PLAN9_CASE_OPTION_FORCE) |
| 272 | { |
| 273 | LOG_WARNING("{} not supported, using {}", PLAN9_CASE_OPTION_FORCE, PLAN9_CASE_OPTION_DIR); |
| 274 | Option = PLAN9_CASE_OPTION_DIR; |
| 275 | } |
| 276 | |
| 277 | Plan9Options += ';'; |
| 278 | Plan9Options += Option; |
| 279 | } |
| 280 | else if (StartsWith(Option, "fallback=")) |
| 281 | { |
| 282 | LOG_WARNING("{} not supported, ignoring...", Option); |
| 283 | } |
| 284 | else |
| 285 | { |
| 286 | StandardOptions += Option; |
| 287 | StandardOptions += ','; |
| 288 | } |
| 289 | } |
| 290 | |
| 291 | Plan9Options += ";" PLAN9_SYMLINK_ROOT_OPTION; |
| 292 | Plan9Options += Config.DrvFsPrefix; |
| 293 | return {std::move(Plan9Options), std::move(StandardOptions)}; |
| 294 | } |
| 295 | |
| 296 | bool IsDrvfsElevated(void) |
| 297 | |
| 298 | /*++ |
| 299 | |
| 300 | Routine Description: |
| 301 | |
| 302 | This routine determines whether drvfs mounts should use the elevated server. |
| 303 | |
| 304 | Arguments: |
| 305 | |
| 306 | None. |
| 307 | |
| 308 | Return Value: |
| 309 | |
| 310 | True if this process should use the elevated server; otherwise, false. |
| 311 | |
| 312 | --*/ |
| 313 | |
| 314 | { |
| 315 | const char* envFlag = getenv(WSL_DRVFS_ELEVATED_ENV); |
| 316 | if (envFlag != nullptr) |
| 317 | { |
| 318 | if (strcmp(envFlag, "0") == 0) |
| 319 | { |
| 320 | return false; |
| 321 | } |
| 322 | else if (strcmp(envFlag, "1") == 0) |
| 323 | { |
| 324 | return true; |
| 325 | } |
| 326 | |
| 327 | LOG_ERROR("Unexpected value for {}: '{}'", WSL_DRVFS_ELEVATED_ENV, envFlag); |
| 328 | } |
| 329 | |
| 330 | // |
| 331 | // Establish a connection to the interop server. If the connection cannot |
| 332 | // be established, use the non-admin DrvFs port. |
| 333 | // |
| 334 | |
| 335 | wsl::shared::SocketChannel channel{UtilConnectToInteropServer(), "InteropClientDrvfs"}; |
| 336 | if (channel.Socket() < 0) |
| 337 | { |
| 338 | return false; |
| 339 | } |
| 340 | |
| 341 | // |
| 342 | // Query the interop server for which port to use. |
| 343 | // |
| 344 | |
| 345 | MESSAGE_HEADER QueryPortMessage{}; |
| 346 | QueryPortMessage.MessageType = LxInitMessageQueryDrvfsElevated; |
| 347 | QueryPortMessage.MessageSize = sizeof(QueryPortMessage); |
| 348 | |
| 349 | auto transaction = channel.StartTransaction(); |
| 350 | transaction.Send(QueryPortMessage); |
| 351 | return transaction.Receive<RESULT_MESSAGE<bool>>().Result; |
| 352 | } |
| 353 | |
| 354 | int MountFilesystem(const char* FsType, const char* Source, const char* Target, const char* Options, int* ExitCode) |
| 355 | |
| 356 | /*++ |
| 357 | |
| 358 | Routine Description: |
| 359 | |
| 360 | This routine will perform a mount using the /bin/mount binary. |
| 361 | |
| 362 | Arguments: |
| 363 | |
| 364 | FsType - Supplies the file system type. |
| 365 | |
| 366 | Source - Supplies the mount source. |
| 367 | |
| 368 | Target - Supplies the mount target. |
| 369 | |
| 370 | Options - Supplies the mount options. |
| 371 | |
| 372 | ExitCode - Supplies an optional pointer that receives the exit code. |
| 373 | |
| 374 | Return Value: |
| 375 | |
| 376 | 0 on success, -1 on failure. |
| 377 | |
| 378 | --*/ |
| 379 | |
| 380 | { |
| 381 | const char* const Argv[] = { |
| 382 | MOUNT_COMMAND, MOUNT_INTERNAL_ONLY_ARG, MOUNT_TYPES_ARG, FsType, Source, Target, MOUNT_OPTIONS_ARG, Options, nullptr}; |
| 383 | |
| 384 | int Status = 0; |
| 385 | const int Result = UtilCreateProcessAndWait(Argv[0], Argv, &Status); |
| 386 | |
| 387 | // |
| 388 | // If the mount process failed, make sure its exit code is propagated. If it terminated |
| 389 | // abnormally or could not be launched, just return failure. |
| 390 | // |
| 391 | |
| 392 | if (ExitCode != nullptr) |
| 393 | { |
| 394 | if (Result < 0) |
| 395 | { |
| 396 | if (WIFEXITED(Status) && Status != 0) |
| 397 | { |
| 398 | *ExitCode = WEXITSTATUS(Status); |
| 399 | } |
| 400 | else |
| 401 | { |
| 402 | *ExitCode = c_exitCodeMountFail; |
| 403 | } |
| 404 | } |
| 405 | else |
| 406 | { |
| 407 | *ExitCode = 0; |
| 408 | } |
| 409 | } |
| 410 | |
| 411 | return Result; |
| 412 | } |
| 413 | |
| 414 | int MountWithRetry(const char* Source, const char* Target, const char* FsType, const char* Options, int* ExitCode) |
| 415 | |
| 416 | /*++ |
| 417 | |
| 418 | Routine Description: |
| 419 | |
| 420 | This routine performs a mount with retry logic for DrvFs filesystems. |
| 421 | |
| 422 | Arguments: |
| 423 | |
| 424 | Source - Supplies the mount source. |
| 425 | |
| 426 | Target - Supplies the mount target. |
| 427 | |
| 428 | FsType - Supplies the filesystem type. |
| 429 | |
| 430 | Options - Supplies the mount options. |
| 431 | |
| 432 | ExitCode - Supplies an optional pointer that receives the exit code. |
| 433 | |
| 434 | Return Value: |
| 435 | |
| 436 | 0 on success, -1 on failure. |
| 437 | |
| 438 | --*/ |
| 439 | |
| 440 | try |
| 441 | { |
| 442 | // |
| 443 | // Verify the target directory exists before mounting. |
| 444 | // |
| 445 | |
| 446 | int Result = access(Target, F_OK); |
| 447 | if (Result < 0) |
| 448 | { |
| 449 | LOG_STDERR(errno); |
| 450 | } |
| 451 | else |
| 452 | { |
| 453 | auto Parsed = mountutil::MountParseFlags(Options); |
| 454 | Result = UtilMount(Source, Target, FsType, Parsed.MountFlags, Parsed.StringOptions.c_str(), std::chrono::seconds{2}); |
| 455 | } |
| 456 | |
| 457 | if (ExitCode) |
| 458 | { |
| 459 | *ExitCode = Result < 0 ? c_exitCodeMountFail : 0; |
| 460 | } |
| 461 | |
| 462 | return Result; |
| 463 | } |
| 464 | CATCH_RETURN_ERRNO() |
| 465 | |
| 466 | int MountDrvfs(const char* Source, const char* Target, const char* Options, std::optional<bool> Admin, const wsl::linux::WslDistributionConfig& Config, int* ExitCode) |
| 467 | |
| 468 | /*++ |
| 469 | |
| 470 | Routine Description: |
| 471 | |
| 472 | This routine will perform a DrvFs mount. |
| 473 | |
| 474 | Arguments: |
| 475 | |
| 476 | Source - Supplies the mount source. |
| 477 | |
| 478 | Target - Supplies the mount target. |
| 479 | |
| 480 | Options - Supplies the mount options. |
| 481 | |
| 482 | Admin - Supplies an optional boolean to specify if the admin or non-admin share should be used. |
| 483 | |
| 484 | ExitCode - Supplies an optional pointer that receives the exit code. |
| 485 | |
| 486 | Return Value: |
| 487 | |
| 488 | 0 on success, -1 on failure. |
| 489 | |
| 490 | --*/ |
| 491 | |
| 492 | try |
| 493 | { |
| 494 | if (!UtilIsUtilityVm()) |
| 495 | { |
| 496 | return MountFilesystem(DRVFS_FS_TYPE, Source, Target, Options, ExitCode); |
| 497 | } |
| 498 | else if (WSL_USE_VIRTIO_FS()) |
| 499 | { |
| 500 | return MountVirtioFs(Source, Target, Options, Admin, Config, ExitCode); |
| 501 | } |
| 502 | |
| 503 | return MountPlan9(Source, Target, Options, Admin, Config, ExitCode); |
| 504 | } |
| 505 | CATCH_RETURN_ERRNO() |
| 506 | |
| 507 | int MountDrvfsEntry(int Argc, char* Argv[]) |
| 508 | |
| 509 | /*++ |
| 510 | |
| 511 | Routine Description: |
| 512 | |
| 513 | This routine is the entrypoint for mount.drvfs. |
| 514 | |
| 515 | Arguments: |
| 516 | |
| 517 | Argc - Supplies the argument count. |
| 518 | |
| 519 | Argv - Supplies the command line arguments. |
| 520 | |
| 521 | Return Value: |
| 522 | |
| 523 | 0 on success, -1 on failure. |
| 524 | |
| 525 | --*/ |
| 526 | |
| 527 | { |
| 528 | if (Argc < 3) |
| 529 | { |
| 530 | LOG_STDERR(EINVAL); |
| 531 | return c_exitCodeInvalidUsage; |
| 532 | } |
| 533 | |
| 534 | // |
| 535 | // Handle mount options if provided. |
| 536 | // |
| 537 | |
| 538 | auto* Options = ""; |
| 539 | if (Argc > 4) |
| 540 | { |
| 541 | Options = Argv[4]; |
| 542 | } |
| 543 | |
| 544 | int ExitCode = c_exitCodeMountFail; |
| 545 | MountDrvfs(Argv[1], Argv[2], Options, {}, wsl::linux::WslDistributionConfig{CONFIG_FILE}, &ExitCode); |
| 546 | return ExitCode; |
| 547 | } |
| 548 | |
| 549 | int MountPlan9Share(const char* Source, const char* Target, const char* Options, bool Admin, int* ExitCode) |
| 550 | |
| 551 | /*++ |
| 552 | |
| 553 | Routine Description: |
| 554 | |
| 555 | This routine will perform a plan 9 mount using the /bin/mount binary. |
| 556 | |
| 557 | Arguments: |
| 558 | |
| 559 | Source - Supplies the mount source. |
| 560 | |
| 561 | Target - Supplies the mount target. |
| 562 | |
| 563 | Options - Supplies the mount options. |
| 564 | |
| 565 | Admin - Supplies a boolean specifying if the admin share should be used. |
| 566 | |
| 567 | ExitCode - Supplies an optional pointer that receives the exit code. |
| 568 | |
| 569 | Return Value: |
| 570 | |
| 571 | 0 on success, -1 on failure. |
| 572 | |
| 573 | --*/ |
| 574 | |
| 575 | { |
| 576 | std::string MountOptions; |
| 577 | if (WSL_USE_VIRTIO_9P()) |
| 578 | { |
| 579 | Source = Admin ? LX_INIT_DRVFS_ADMIN_VIRTIO_TAG : LX_INIT_DRVFS_VIRTIO_TAG; |
| 580 | MountOptions = std::format("msize=262144,trans=virtio,{}", Options); |
| 581 | return MountWithRetry(Source, Target, PLAN9_FS_TYPE, MountOptions.c_str(), ExitCode); |
| 582 | } |
| 583 | else |
| 584 | { |
| 585 | auto Port = Admin ? LX_INIT_UTILITY_VM_PLAN9_DRVFS_ADMIN_PORT : LX_INIT_UTILITY_VM_PLAN9_DRVFS_PORT; |
| 586 | wil::unique_fd Fd{UtilConnectVsock(Port, false, LX_INIT_UTILITY_VM_PLAN9_BUFFER_SIZE)}; |
| 587 | if (!Fd) |
| 588 | { |
| 589 | return -1; |
| 590 | } |
| 591 | |
| 592 | MountOptions = |
| 593 | std::format("msize={},trans=fd,rfdno={},wfdno={},{}", LX_INIT_UTILITY_VM_PLAN9_BUFFER_SIZE, Fd.get(), Fd.get(), Options); |
| 594 | |
| 595 | return MountFilesystem(PLAN9_FS_TYPE, Source, Target, MountOptions.c_str(), ExitCode); |
| 596 | } |
| 597 | } |
| 598 | |
| 599 | int MountPlan9(const char* Source, const char* Target, const char* Options, std::optional<bool> Admin, const wsl::linux::WslDistributionConfig& Config, int* ExitCode) |
| 600 | |
| 601 | /*++ |
| 602 | |
| 603 | Routine Description: |
| 604 | |
| 605 | This routine will perform a DrvFs mount using Plan9. |
| 606 | |
| 607 | Arguments: |
| 608 | |
| 609 | Source - Supplies the mount source. |
| 610 | |
| 611 | Target - Supplies the mount target. |
| 612 | |
| 613 | Options - Supplies the mount options. |
| 614 | |
| 615 | Admin - Supplies an optional boolean to specify if the admin or non-admin share should be used. |
| 616 | |
| 617 | Config - Supplies the distribution configuration. |
| 618 | |
| 619 | ExitCode - Supplies an optional pointer that receives the exit code. |
| 620 | |
| 621 | Return Value: |
| 622 | |
| 623 | 0 on success, -1 on failure. |
| 624 | |
| 625 | --*/ |
| 626 | |
| 627 | try |
| 628 | { |
| 629 | // |
| 630 | // Check if the path is a UNC path. |
| 631 | // |
| 632 | |
| 633 | const char* Plan9Source; |
| 634 | std::string UncSource; |
| 635 | if ((strlen(Source) >= PLAN9_UNC_PREFIX_LENGTH) && ((Source[0] == '/') || (Source[0] == '\\')) && |
| 636 | ((Source[1] == '/') || (Source[1] == '\\'))) |
| 637 | { |
| 638 | UncSource = PLAN9_UNC_TRANSLATED_PREFIX; |
| 639 | UncSource += &Source[PLAN9_UNC_PREFIX_LENGTH]; |
| 640 | Plan9Source = UncSource.c_str(); |
| 641 | } |
| 642 | else |
| 643 | { |
| 644 | Plan9Source = Source; |
| 645 | } |
| 646 | |
| 647 | // |
| 648 | // Check whether to use the elevated or regular 9p server. |
| 649 | // |
| 650 | |
| 651 | bool Elevated = Admin.has_value() ? Admin.value() : IsDrvfsElevated(); |
| 652 | |
| 653 | // |
| 654 | // Initialize mount options. |
| 655 | // |
| 656 | |
| 657 | auto Plan9Options = std::format("{};path={}", PLAN9_ANAME_DRVFS, Plan9Source); |
| 658 | |
| 659 | // |
| 660 | // N.B. The cache option is added to the start of this so if the user |
| 661 | // specifies one explicitly, it will override the default. |
| 662 | // |
| 663 | |
| 664 | std::string MountOptions = "cache=mmap,"; |
| 665 | auto ParsedOptions = ConvertDrvfsMountOptionsToPlan9(Options ? Options : "", Config); |
| 666 | Plan9Options += ParsedOptions.first; |
| 667 | MountOptions += ParsedOptions.second; |
| 668 | |
| 669 | // |
| 670 | // Append the 9p mount options to the end of the other mount options and perform the mount operation. |
| 671 | // |
| 672 | |
| 673 | MountOptions += Plan9Options; |
| 674 | if (MountPlan9Share(Source, Target, MountOptions.c_str(), Elevated, ExitCode) < 0) |
| 675 | { |
| 676 | return -1; |
| 677 | } |
| 678 | |
| 679 | return 0; |
| 680 | } |
| 681 | CATCH_RETURN_ERRNO() |
| 682 | |
| 683 | int MountVirtioFs(const char* Source, const char* Target, const char* Options, std::optional<bool> Admin, const wsl::linux::WslDistributionConfig& Config, int* ExitCode) |
| 684 | |
| 685 | /*++ |
| 686 | |
| 687 | Routine Description: |
| 688 | |
| 689 | This routine mounts a virtiofs share. The DrvFs mount options are converted into 9p mount options |
| 690 | which are used to determine behavior when the device is added to the host. |
| 691 | |
| 692 | Arguments: |
| 693 | |
| 694 | Source - Supplies the mount source. |
| 695 | |
| 696 | Target - Supplies the mount target. |
| 697 | |
| 698 | Options - Supplies DrvFs mount options to translate into Plan9 mount |
| 699 | options. |
| 700 | |
| 701 | Admin - Supplies an optional boolean to specify if the admin or non-admin server should be used. |
| 702 | |
| 703 | ExitCode - Supplies an optional pointer that receives the exit code. |
| 704 | |
| 705 | Return Value: |
| 706 | |
| 707 | 0 on success, -1 on failure. |
| 708 | |
| 709 | --*/ |
| 710 | |
| 711 | try |
| 712 | { |
| 713 | assert(WSL_USE_VIRTIO_FS()); |
| 714 | |
| 715 | // |
| 716 | // Check whether to use the elevated or non-elevated virtiofs server. |
| 717 | // |
| 718 | |
| 719 | if (!Admin.has_value()) |
| 720 | { |
| 721 | Admin = IsDrvfsElevated(); |
| 722 | } |
| 723 | |
| 724 | // |
| 725 | // Convert the DrvFs mount options. |
| 726 | // |
| 727 | // N.B. Since virtiofs does not allow passing mount options, the 9p mount options are used to specify share |
| 728 | // behavior when creating virtiofs shares on the host. |
| 729 | // |
| 730 | |
| 731 | auto [Plan9Options, MountOptions] = ConvertDrvfsMountOptionsToPlan9(Options ? Options : "", Config); |
| 732 | const auto ParsedOptions = mountutil::MountParseFlags(MountOptions); |
| 733 | if ((ParsedOptions.MountFlags & MS_RDONLY) != 0) |
| 734 | { |
| 735 | Plan9Options += ";ro"; |
| 736 | } |
| 737 | |
| 738 | // |
| 739 | // Construct a request to add a virtiofs share. |
| 740 | // |
| 741 | |
| 742 | wsl::shared::MessageWriter<LX_INIT_ADD_VIRTIOFS_SHARE_MESSAGE> AddShare(LxInitMessageAddVirtioFsDevice); |
| 743 | AddShare->Admin = Admin.value(); |
| 744 | AddShare.WriteString(AddShare->PathOffset, Source); |
| 745 | AddShare.WriteString(AddShare->OptionsOffset, Plan9Options); |
| 746 | |
| 747 | // |
| 748 | // Connect to the wsl service to add the virtiofs share. If adding the share fails, fallback to mounting using Plan9. |
| 749 | // |
| 750 | |
| 751 | wsl::shared::SocketChannel Channel{UtilConnectVsock(LX_INIT_UTILITY_VM_VIRTIOFS_PORT, true), "VirtoFs"}; |
| 752 | if (Channel.Socket() < 0) |
| 753 | { |
| 754 | return -1; |
| 755 | } |
| 756 | |
| 757 | gsl::span<gsl::byte> ResponseSpan; |
| 758 | const auto& Response = Channel.Transaction<LX_INIT_ADD_VIRTIOFS_SHARE_MESSAGE>(AddShare.Span(), &ResponseSpan); |
| 759 | if (Response.Result != 0) |
| 760 | { |
| 761 | LOG_WARNING("Add virtiofs share for {} failed {}, falling back to Plan9", Source, Response.Result); |
| 762 | return MountPlan9(Source, Target, Options, Admin, Config, ExitCode); |
| 763 | } |
| 764 | |
| 765 | // |
| 766 | // Perform the mount operation. |
| 767 | // |
| 768 | |
| 769 | auto* Tag = wsl::shared::string::FromSpan(ResponseSpan, Response.TagOffset); |
| 770 | auto* ChildName = wsl::shared::string::FromSpan(ResponseSpan, Response.ChildNameOffset); |
| 771 | auto* ResponseSource = wsl::shared::string::FromSpan(ResponseSpan, Response.SourceOffset); |
| 772 | const char* MappingName = Tag; |
| 773 | if (*ChildName == '\0') |
| 774 | { |
| 775 | THROW_LAST_ERROR_IF(MountWithRetry(Tag, Target, VIRTIO_FS_TYPE, MountOptions.c_str(), ExitCode) < 0); |
| 776 | } |
| 777 | else if (MountVirtioFsChild(Tag, ChildName, Target, MountOptions.c_str(), ExitCode) < 0) |
| 778 | { |
| 779 | const auto childError = errno; |
| 780 | LOG_WARNING("Mounting virtiofs child for {} failed {}, falling back to Plan9", Source, childError); |
| 781 | |
| 782 | return MountPlan9(Source, Target, Options, Admin, Config, ExitCode); |
| 783 | } |
| 784 | else |
| 785 | { |
| 786 | MappingName = ChildName; |
| 787 | } |
| 788 | |
| 789 | // |
| 790 | // Save the tag mapping. |
| 791 | // |
| 792 | // N.B. Use the source path from the response since the service canonicalizes it. |
| 793 | // |
| 794 | |
| 795 | SaveVirtiofsTagMapping(MappingName, ResponseSource); |
| 796 | |
| 797 | return 0; |
| 798 | } |
| 799 | CATCH_RETURN_ERRNO() |
| 800 | |
| 801 | int RemountVirtioFs(const char* Tag, const char* Target, const char* Options, bool Admin, std::string_view SubPath) |
| 802 | |
| 803 | /*++ |
| 804 | |
| 805 | Routine Description: |
| 806 | |
| 807 | This routine translates DrvFs mount options into Plan9 mount options and |
| 808 | mounts the share. |
| 809 | |
| 810 | Arguments: |
| 811 | |
| 812 | Tag - Supplies the virtiofs tag to remount. |
| 813 | |
| 814 | Target - Supplies the mount target. |
| 815 | |
| 816 | Options - Supplies mount options. |
| 817 | |
| 818 | Admin - Supplies a boolean to specify if the admin or non-admin server should be used. |
| 819 | |
| 820 | Return Value: |
| 821 | |
| 822 | 0 on success, -1 on failure. |
| 823 | |
| 824 | --*/ |
| 825 | |
| 826 | try |
| 827 | { |
| 828 | assert(WSL_USE_VIRTIO_FS()); |
| 829 | |
| 830 | wsl::shared::MessageWriter<LX_INIT_REMOUNT_VIRTIOFS_SHARE_MESSAGE> RemountShare(LxInitMessageRemountVirtioFsDevice); |
| 831 | RemountShare->Admin = Admin; |
| 832 | RemountShare.WriteString(RemountShare->TagOffset, Tag); |
| 833 | |
| 834 | // |
| 835 | // Connect to the host and send the remount request. |
| 836 | // |
| 837 | |
| 838 | wsl::shared::SocketChannel Channel{UtilConnectVsock(LX_INIT_UTILITY_VM_VIRTIOFS_PORT, true), "RemountVirtioFs"}; |
| 839 | if (Channel.Socket() < 0) |
| 840 | { |
| 841 | return -1; |
| 842 | } |
| 843 | |
| 844 | gsl::span<gsl::byte> ResponseSpan; |
| 845 | const auto& Response = Channel.Transaction<LX_INIT_REMOUNT_VIRTIOFS_SHARE_MESSAGE>(RemountShare.Span(), &ResponseSpan); |
| 846 | if (Response.Result != 0) |
| 847 | { |
| 848 | LOG_ERROR("Remount virtiofs share for {} failed {}", Tag, Response.Result); |
| 849 | return -1; |
| 850 | } |
| 851 | |
| 852 | auto* NewTag = wsl::shared::string::FromSpan(ResponseSpan, Response.TagOffset); |
| 853 | auto* ChildName = wsl::shared::string::FromSpan(ResponseSpan, Response.ChildNameOffset); |
| 854 | auto* Source = wsl::shared::string::FromSpan(ResponseSpan, Response.SourceOffset); |
| 855 | const char* MappingName = NewTag; |
| 856 | if (*ChildName == '\0') |
| 857 | { |
| 858 | THROW_LAST_ERROR_IF(MountWithRetry(NewTag, Target, VIRTIO_FS_TYPE, Options) < 0); |
| 859 | } |
| 860 | else |
| 861 | { |
| 862 | THROW_LAST_ERROR_IF(MountVirtioFsChild(NewTag, ChildName, Target, Options, nullptr, SubPath) < 0); |
| 863 | MappingName = ChildName; |
| 864 | } |
| 865 | |
| 866 | SaveVirtiofsTagMapping(MappingName, Source); |
| 867 | |
| 868 | return 0; |
| 869 | } |
| 870 | CATCH_RETURN_ERRNO() |
| 871 | |
| 872 | std::string QueryVirtiofsMountSource(const char* Tag, const char* Root) |
| 873 | |
| 874 | /*++ |
| 875 | |
| 876 | Routine Description: |
| 877 | |
| 878 | This routine takes a virtiofs tag and determines the Windows path it refers to |
| 879 | by reading the symlink created during mount. |
| 880 | |
| 881 | Arguments: |
| 882 | |
| 883 | Tag - Supplies the virtiofs tag to query. |
| 884 | |
| 885 | Root - Optionally supplies the mountinfo root for an aggregate child. |
| 886 | |
| 887 | Return Value: |
| 888 | |
| 889 | The mount source, an empty string on failure. |
| 890 | |
| 891 | --*/ |
| 892 | |
| 893 | try |
| 894 | { |
| 895 | if (!WSL_USE_VIRTIO_FS()) |
| 896 | { |
| 897 | return {}; |
| 898 | } |
| 899 | |
| 900 | std::string mappingName{Tag}; |
| 901 | if (Root != nullptr) |
| 902 | { |
| 903 | if (const auto mountRoot = ParseAggregateVirtioFsMountRoot(Tag, Root)) |
| 904 | { |
| 905 | mappingName = mountRoot->ChildName; |
| 906 | } |
| 907 | } |
| 908 | |
| 909 | const auto Guid = wsl::shared::string::ToGuid(mappingName); |
| 910 | if (!Guid) |
| 911 | { |
| 912 | return {}; |
| 913 | } |
| 914 | |
| 915 | // |
| 916 | // Read the symlink that maps this tag to its Windows source path. |
| 917 | // |
| 918 | |
| 919 | auto LinkPath = std::format("{}/{}", VIRTIOFS_TAG_DIR, mappingName); |
| 920 | return std::filesystem::read_symlink(LinkPath).string(); |
| 921 | } |
| 922 | catch (...) |
| 923 | { |
| 924 | LOG_CAUGHT_EXCEPTION(); |
| 925 | return {}; |
| 926 | } |