| 1 | // Copyright (C) Microsoft Corporation. All rights reserved. |
| 2 | #include "precomp.h" |
| 3 | #include "p9errors.h" |
| 4 | #include "p9file.h" |
| 5 | #include "p9util.h" |
| 6 | #include "p9commonutil.h" |
| 7 | #include "p9xattr.h" |
| 8 | #include <mountutilcpp.h> |
| 9 | #include <sys/syscall.h> |
| 10 | #include <sys/sysmacros.h> |
| 11 | |
| 12 | using namespace std::string_view_literals; |
| 13 | |
| 14 | namespace p9fs { |
| 15 | |
| 16 | constexpr std::string_view c_drvfsFsType = "drvfs"sv; |
| 17 | constexpr std::string_view c_p9FsType = "9p"sv; |
| 18 | constexpr std::string_view c_virtioFsType = "virtiofs"sv; |
| 19 | |
| 20 | struct OpenFlagMapping |
| 21 | { |
| 22 | OpenFlags P9Flag; |
| 23 | int LinuxFlag; |
| 24 | }; |
| 25 | |
| 26 | const OpenFlagMapping c_openFlagsMapping[] = { |
| 27 | {OpenFlags::WriteOnly, O_WRONLY}, |
| 28 | {OpenFlags::ReadWrite, O_RDWR}, |
| 29 | {OpenFlags::Create, O_CREAT}, |
| 30 | {OpenFlags::Exclusive, O_EXCL}, |
| 31 | {OpenFlags::NoCTTY, O_NOCTTY}, |
| 32 | {OpenFlags::Truncate, O_TRUNC}, |
| 33 | {OpenFlags::Append, O_APPEND}, |
| 34 | {OpenFlags::NonBlock, O_NONBLOCK}, |
| 35 | {OpenFlags::DSync, O_DSYNC}, |
| 36 | {OpenFlags::FAsync, O_ASYNC}, |
| 37 | {OpenFlags::Direct, O_DIRECT}, |
| 38 | {OpenFlags::LargeFile, O_LARGEFILE}, |
| 39 | {OpenFlags::Directory, O_DIRECTORY}, |
| 40 | {OpenFlags::NoFollow, O_NOFOLLOW}, |
| 41 | {OpenFlags::NoAccessTime, O_NOATIME}, |
| 42 | {OpenFlags::CloseOnExec, O_CLOEXEC}, |
| 43 | {OpenFlags::Sync, O_SYNC}}; |
| 44 | |
| 45 | Expected<std::tuple<std::shared_ptr<Fid>, Qid>> CreateFile(std::shared_ptr<const IRoot> root, LX_UID_T uid) |
| 46 | { |
| 47 | auto realRoot = std::static_pointer_cast<const Root>(root); |
| 48 | auto file = std::make_shared<File>(realRoot); |
| 49 | auto qid = file->Initialize(); |
| 50 | if (!qid) |
| 51 | { |
| 52 | return qid.Unexpected(); |
| 53 | } |
| 54 | |
| 55 | return std::tuple<std::shared_ptr<Fid>, Qid>{std::move(file), qid.Get()}; |
| 56 | } |
| 57 | |
| 58 | QidType ModeToQidType(mode_t mode) |
| 59 | { |
| 60 | if (S_ISLNK(mode)) |
| 61 | { |
| 62 | return QidType::Symlink; |
| 63 | } |
| 64 | |
| 65 | if (S_ISDIR(mode)) |
| 66 | { |
| 67 | return QidType::Directory; |
| 68 | } |
| 69 | |
| 70 | return QidType::File; |
| 71 | } |
| 72 | |
| 73 | // Converts the result of a stat system call to a qid value. |
| 74 | Qid StatToQid(const struct stat& st) |
| 75 | { |
| 76 | return {st.st_ino, 0, ModeToQidType(st.st_mode)}; |
| 77 | } |
| 78 | |
| 79 | // Get the qid for a file. |
| 80 | // N.B. The caller is responsible for setting the right thread uid/gid before calling this. |
| 81 | Expected<Qid> GetFileQidByPath(int fd, const std::string& path) |
| 82 | { |
| 83 | struct stat st; |
| 84 | int result = fstatat(fd, path.c_str(), &st, AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH); |
| 85 | if (result < 0) |
| 86 | { |
| 87 | return LxError{-errno}; |
| 88 | } |
| 89 | |
| 90 | return StatToQid(st); |
| 91 | } |
| 92 | |
| 93 | // Appends a valid Linux path segment to a Win32 path. It's assumed that the path has already been |
| 94 | // scanned for internal NUL and / characters. |
| 95 | void AppendPath(std::string& Base, std::string_view Name) |
| 96 | { |
| 97 | // No need for a delimiter if the base path is empty or already ends in one. |
| 98 | if (!Base.empty() && Base.back() != '/') |
| 99 | { |
| 100 | Base += '/'; |
| 101 | } |
| 102 | |
| 103 | Base += Name; |
| 104 | } |
| 105 | |
| 106 | // Converts 9P2000.L open flags to Linux open flags. |
| 107 | // N.B. 9P2000.L and Linux flag values may be identical on some platforms, but not all. |
| 108 | int OpenFlagsToLinuxFlags(OpenFlags flags) |
| 109 | { |
| 110 | // Since OpenFlags::ReadOnly is zero, it's omitted from the mapping array. This is safe as long as O_RDONLY is also |
| 111 | // zero. If it's not, it would have to be handled separately. |
| 112 | static_assert(O_RDONLY == 0); |
| 113 | |
| 114 | int result = 0; |
| 115 | for (const auto& flag : c_openFlagsMapping) |
| 116 | { |
| 117 | if (WI_AreAllFlagsSet(flags, flag.P9Flag)) |
| 118 | { |
| 119 | WI_SetAllFlags(result, flag.LinuxFlag); |
| 120 | } |
| 121 | } |
| 122 | |
| 123 | return result; |
| 124 | } |
| 125 | |
| 126 | // Get the stat information of this file. |
| 127 | // N.B. The caller is responsible for setting the right thread uid/gid before calling this. |
| 128 | Expected<struct stat> File::Stat() |
| 129 | { |
| 130 | struct stat st; |
| 131 | // Acquire the lock to prevent the file name from changing. |
| 132 | std::shared_lock<std::shared_mutex> lock{m_Lock}; |
| 133 | int result = fstatat(m_Root->RootFd, m_FileName.c_str(), &st, AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH); |
| 134 | if (result < 0) |
| 135 | { |
| 136 | return LxError{-errno}; |
| 137 | } |
| 138 | |
| 139 | return st; |
| 140 | } |
| 141 | |
| 142 | bool File::IsOnRoot(const std::shared_ptr<const IRoot>& root) |
| 143 | { |
| 144 | return m_Root == root; |
| 145 | } |
| 146 | |
| 147 | // Opens the file. |
| 148 | // N.B. The caller is responsible for setting the right thread uid/gid before calling this. |
| 149 | Expected<wil::unique_fd> File::OpenFile(int openFlags) |
| 150 | { |
| 151 | // Acquire the lock to prevent the file name from changing. |
| 152 | std::shared_lock<std::shared_mutex> lock{m_Lock}; |
| 153 | return util::OpenAt(m_Root->RootFd, m_FileName, openFlags | O_NOFOLLOW); |
| 154 | } |
| 155 | |
| 156 | // Validates that this file exists and sets the m_Qid member. |
| 157 | // N.B. The caller is responsible for setting the right thread uid/gid before calling this. |
| 158 | LX_INT File::ValidateExists() |
| 159 | { |
| 160 | auto st = Stat(); |
| 161 | if (!st) |
| 162 | { |
| 163 | return st.Error(); |
| 164 | } |
| 165 | |
| 166 | m_Qid = StatToQid(st.Get()); |
| 167 | m_Device = st->st_dev; |
| 168 | return {}; |
| 169 | } |
| 170 | |
| 171 | // Initializes a file to a Win32 path. |
| 172 | Expected<Qid> File::Initialize() |
| 173 | { |
| 174 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 175 | LX_INT error = ValidateExists(); |
| 176 | if (error < 0) |
| 177 | { |
| 178 | return LxError{error}; |
| 179 | } |
| 180 | |
| 181 | // No locking needed because initialize is only called on fids not yet |
| 182 | // reachable by other threads. |
| 183 | return m_Qid; |
| 184 | } |
| 185 | |
| 186 | File::File(std::shared_ptr<const Root> root) : m_Root{root} |
| 187 | { |
| 188 | } |
| 189 | |
| 190 | // Copies a file. This does not clone the open file state, just the name and metadata. |
| 191 | File::File(const File& file) : m_FileName{file.m_FileName}, m_Root{file.m_Root}, m_Qid{file.m_Qid}, m_Device{file.m_Device} |
| 192 | { |
| 193 | } |
| 194 | |
| 195 | // Updates the path to a child file entry in a directory. Must be called with a newly |
| 196 | // constructed file, not one that has been opened. |
| 197 | Expected<Qid> File::Walk(std::string_view name) |
| 198 | { |
| 199 | // TODO: This is not safe if walk is called multiple times. While |
| 200 | // we verify that the item is not a symlink in this step, the file could've |
| 201 | // been replaced with a symlink since the qid was determined. |
| 202 | // The only way to make this foolproof is to open an fd for every file, and |
| 203 | // use fstatat for the next level. A chroot environment can be used to |
| 204 | // prevent the links from escaping the share root, but it can't avoid |
| 205 | // accidentally following links at all. |
| 206 | if (!WI_IsFlagSet(m_Qid.Type, QidType::Directory)) |
| 207 | { |
| 208 | return LxError{LX_ENOTDIR}; |
| 209 | } |
| 210 | |
| 211 | // No lock is taken here; this function is only called on fid's that have |
| 212 | // not yet been inserted in the list and are therefore not reachable from |
| 213 | // other threads. |
| 214 | AppendPath(m_FileName, name); |
| 215 | |
| 216 | // Revert to the old info on error. |
| 217 | const auto oldQid = m_Qid; |
| 218 | const auto oldDevice = m_Device; |
| 219 | auto restoreName = wil::scope_exit([&]() { |
| 220 | m_Qid = oldQid; |
| 221 | m_Device = oldDevice; |
| 222 | const auto index = m_FileName.find_last_of('/'); |
| 223 | if (index == std::string::npos) |
| 224 | { |
| 225 | m_FileName.resize(0); |
| 226 | } |
| 227 | else |
| 228 | { |
| 229 | m_FileName.resize(index); |
| 230 | } |
| 231 | }); |
| 232 | |
| 233 | // TODO: Maybe handle multiple items in a single walk call so changing ids is done only once. |
| 234 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 235 | const auto parentDevice = m_Device; |
| 236 | LX_INT err = ValidateExists(); |
| 237 | if (err != 0) |
| 238 | { |
| 239 | return LxError{err}; |
| 240 | } |
| 241 | |
| 242 | // Check if this is a mount point, and if so if it's a drvfs or 9p mount. |
| 243 | if (parentDevice != m_Device) |
| 244 | { |
| 245 | try |
| 246 | { |
| 247 | // Because this thread might not be in the same mount namespace than the rest of the process, |
| 248 | // look at /proc/<tid>/mountinfo instead of /proc/self/ |
| 249 | const std::string mountInfoPath = std::format("/proc/{}/mountinfo", gettid()); |
| 250 | mountutil::MountEnum mountEnum(mountInfoPath.c_str()); |
| 251 | bool found = mountEnum.FindMount([this](auto entry) { return entry.Device == m_Device; }); |
| 252 | |
| 253 | // If the mount was found and it's a drvfs mount, deny access. |
| 254 | if (found && (mountEnum.Current().FileSystemType == c_drvfsFsType || mountEnum.Current().FileSystemType == c_p9FsType || |
| 255 | mountEnum.Current().FileSystemType == c_virtioFsType)) |
| 256 | { |
| 257 | return LxError{LX_EACCES}; |
| 258 | } |
| 259 | } |
| 260 | CATCH_LOG() |
| 261 | } |
| 262 | |
| 263 | restoreName.release(); |
| 264 | return m_Qid; |
| 265 | } |
| 266 | |
| 267 | // Reads the attributes of a file or directory. |
| 268 | Expected<std::tuple<UINT64, Qid, StatResult>> File::GetAttr(UINT64 mask) |
| 269 | { |
| 270 | std::string fileName; |
| 271 | Qid qid; |
| 272 | { |
| 273 | // Retrieve the qid and open a handle under lock. |
| 274 | std::shared_lock<std::shared_mutex> lock{m_Lock}; |
| 275 | qid = m_Qid; |
| 276 | fileName = m_FileName; |
| 277 | } |
| 278 | |
| 279 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 280 | struct stat stat; |
| 281 | int error = fstatat(m_Root->RootFd, fileName.c_str(), &stat, AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH); |
| 282 | if (error < 0) |
| 283 | { |
| 284 | return LxError{-errno}; |
| 285 | } |
| 286 | |
| 287 | StatResult result{}; |
| 288 | UINT64 valid = GetAttrIno; |
| 289 | if (WI_IsFlagSet(mask, GetAttrMode)) |
| 290 | { |
| 291 | result.Mode = stat.st_mode; |
| 292 | WI_SetFlag(valid, GetAttrMode); |
| 293 | } |
| 294 | |
| 295 | if (WI_IsFlagSet(mask, GetAttrNlink)) |
| 296 | { |
| 297 | result.NLink = stat.st_nlink; |
| 298 | WI_SetFlag(valid, GetAttrNlink); |
| 299 | } |
| 300 | |
| 301 | if (WI_IsFlagSet(mask, GetAttrRdev)) |
| 302 | { |
| 303 | result.RDev = stat.st_rdev; |
| 304 | WI_SetFlag(valid, GetAttrRdev); |
| 305 | } |
| 306 | |
| 307 | if (WI_IsFlagSet(mask, GetAttrSize)) |
| 308 | { |
| 309 | result.Size = stat.st_size; |
| 310 | WI_SetFlag(valid, GetAttrSize); |
| 311 | } |
| 312 | |
| 313 | if (WI_IsFlagSet(mask, GetAttrBlocks)) |
| 314 | { |
| 315 | result.BlockSize = stat.st_blksize; |
| 316 | result.Blocks = stat.st_blocks; |
| 317 | WI_SetFlag(valid, GetAttrBlocks); |
| 318 | } |
| 319 | |
| 320 | if (WI_IsFlagSet(mask, GetAttrAtime)) |
| 321 | { |
| 322 | result.AtimeSec = stat.st_atim.tv_sec; |
| 323 | result.AtimeNsec = stat.st_atim.tv_nsec; |
| 324 | WI_SetFlag(valid, GetAttrAtime); |
| 325 | } |
| 326 | |
| 327 | if (WI_IsFlagSet(mask, GetAttrMtime)) |
| 328 | { |
| 329 | result.MtimeSec = stat.st_mtim.tv_sec; |
| 330 | result.MtimeNsec = stat.st_mtim.tv_nsec; |
| 331 | WI_SetFlag(valid, GetAttrMtime); |
| 332 | } |
| 333 | |
| 334 | if (WI_IsFlagSet(mask, GetAttrCtime)) |
| 335 | { |
| 336 | result.CtimeSec = stat.st_ctim.tv_sec; |
| 337 | result.CtimeNsec = stat.st_ctim.tv_nsec; |
| 338 | WI_SetFlag(valid, GetAttrCtime); |
| 339 | } |
| 340 | |
| 341 | if (WI_IsFlagSet(mask, GetAttrUid)) |
| 342 | { |
| 343 | result.Uid = stat.st_uid; |
| 344 | WI_SetFlag(valid, GetAttrUid); |
| 345 | } |
| 346 | |
| 347 | if (WI_IsFlagSet(mask, GetAttrGid)) |
| 348 | { |
| 349 | result.Gid = stat.st_gid; |
| 350 | WI_SetFlag(valid, GetAttrGid); |
| 351 | } |
| 352 | |
| 353 | return std::make_tuple(valid, qid, result); |
| 354 | } |
| 355 | |
| 356 | // Sets the attributes for a file or directory. |
| 357 | LX_INT File::SetAttr(UINT32 valid, const StatResult& stat) |
| 358 | { |
| 359 | if (m_Root->ReadOnly()) |
| 360 | { |
| 361 | return LX_EROFS; |
| 362 | } |
| 363 | |
| 364 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 365 | |
| 366 | // Multiple operations may be performed, so it would be preferable to open the file. However, |
| 367 | // most operations don't support O_PATH and any other flags will check for permissions that the |
| 368 | // operation may not need. |
| 369 | const auto fileName = GetFileName(); |
| 370 | |
| 371 | // Ctime is updated by most of the operations below, so don't explicitly |
| 372 | // update it if not needed. |
| 373 | bool needCTimeUpdate = WI_IsFlagSet(valid, SetAttrCtime); |
| 374 | |
| 375 | if (WI_IsFlagSet(valid, SetAttrSize)) |
| 376 | { |
| 377 | // Open the file to truncate because truncate will always follow symlinks and there is no |
| 378 | // ftruncateat. |
| 379 | auto file = OpenFile(O_WRONLY); |
| 380 | if (!file) |
| 381 | { |
| 382 | return file.Error(); |
| 383 | } |
| 384 | |
| 385 | int error = ftruncate(file->get(), stat.Size); |
| 386 | if (error < 0) |
| 387 | { |
| 388 | return -errno; |
| 389 | } |
| 390 | |
| 391 | needCTimeUpdate = false; |
| 392 | } |
| 393 | |
| 394 | if (WI_IsFlagSet(valid, SetAttrMode)) |
| 395 | { |
| 396 | int error = fchmodat(m_Root->RootFd, fileName.c_str(), stat.Mode, AT_SYMLINK_NOFOLLOW); |
| 397 | if (error < 0) |
| 398 | { |
| 399 | return -errno; |
| 400 | } |
| 401 | |
| 402 | needCTimeUpdate = false; |
| 403 | } |
| 404 | |
| 405 | if (WI_IsAnyFlagSet(valid, SetAttrUid | SetAttrGid)) |
| 406 | { |
| 407 | uid_t uid = WI_IsFlagSet(valid, SetAttrUid) ? stat.Uid : -1; |
| 408 | uid_t gid = WI_IsFlagSet(valid, SetAttrGid) ? stat.Gid : -1; |
| 409 | int error = fchownat(m_Root->RootFd, fileName.c_str(), uid, gid, AT_SYMLINK_NOFOLLOW); |
| 410 | if (error < 0) |
| 411 | { |
| 412 | return -errno; |
| 413 | } |
| 414 | |
| 415 | needCTimeUpdate = false; |
| 416 | } |
| 417 | |
| 418 | if (WI_IsAnyFlagSet(valid, SetAttrAtime | SetAttrMtime)) |
| 419 | { |
| 420 | struct timespec times[2]{{0, UTIME_OMIT}, {0, UTIME_OMIT}}; |
| 421 | |
| 422 | // |
| 423 | // For atime and mtime, the time is set to the current time unless the |
| 424 | // respective "set" flag is set. |
| 425 | // |
| 426 | |
| 427 | if (WI_IsFlagSet(valid, SetAttrAtime)) |
| 428 | { |
| 429 | if (WI_IsFlagSet(valid, SetAttrAtimeSet)) |
| 430 | { |
| 431 | times[0].tv_sec = stat.AtimeSec; |
| 432 | times[0].tv_nsec = stat.AtimeNsec; |
| 433 | } |
| 434 | else |
| 435 | { |
| 436 | times[0].tv_nsec = UTIME_NOW; |
| 437 | } |
| 438 | } |
| 439 | |
| 440 | if (WI_IsFlagSet(valid, SetAttrMtime)) |
| 441 | { |
| 442 | if (WI_IsFlagSet(valid, SetAttrMtimeSet)) |
| 443 | { |
| 444 | times[1].tv_sec = stat.MtimeSec; |
| 445 | times[1].tv_nsec = stat.MtimeNsec; |
| 446 | } |
| 447 | else |
| 448 | { |
| 449 | times[1].tv_nsec = UTIME_NOW; |
| 450 | } |
| 451 | } |
| 452 | |
| 453 | int error = utimensat(m_Root->RootFd, fileName.c_str(), times, AT_SYMLINK_NOFOLLOW); |
| 454 | if (error < 0) |
| 455 | { |
| 456 | return -errno; |
| 457 | } |
| 458 | |
| 459 | needCTimeUpdate = false; |
| 460 | } |
| 461 | |
| 462 | // If a ctime update was requested but didn't already happen, perform a no-op |
| 463 | // operation that has a ctime update as a side-effect. |
| 464 | if (needCTimeUpdate) |
| 465 | { |
| 466 | int error = fchownat(m_Root->RootFd, fileName.c_str(), -1, -1, AT_SYMLINK_NOFOLLOW); |
| 467 | if (error < 0) |
| 468 | { |
| 469 | return -errno; |
| 470 | } |
| 471 | } |
| 472 | |
| 473 | return {}; |
| 474 | } |
| 475 | |
| 476 | // Opens a file or directory for read/write access. |
| 477 | Expected<Qid> File::Open(OpenFlags flags) |
| 478 | { |
| 479 | // Acquire the lock to protect the file name and to guard against |
| 480 | // concurrent open attempts. |
| 481 | std::lock_guard<std::shared_mutex> lock{m_Lock}; |
| 482 | if (IsOpen()) |
| 483 | { |
| 484 | return LxError{LX_EINVAL}; |
| 485 | } |
| 486 | |
| 487 | WI_ClearFlag(flags, OpenFlags::Create); |
| 488 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 489 | // Don't use OpenHandle because the lock is already held. |
| 490 | auto file{util::OpenAt(m_Root->RootFd, m_FileName, OpenFlagsToLinuxFlags(flags) | O_NOFOLLOW)}; |
| 491 | if (!file) |
| 492 | { |
| 493 | return file.Unexpected(); |
| 494 | } |
| 495 | |
| 496 | m_Io = CoroutineIoIssuer(file->get()); |
| 497 | m_File = std::move(file.Get()); |
| 498 | return m_Qid; |
| 499 | } |
| 500 | |
| 501 | // Creates a file in a directory, updating this object to point to the new file. |
| 502 | Expected<Qid> File::Create(std::string_view name, OpenFlags flags, UINT32 mode, UINT32 /* gid */) |
| 503 | { |
| 504 | // Acquire the lock exclusive because the file name will be modified, |
| 505 | // and to protect against concurrent opens and creates. |
| 506 | std::lock_guard<std::shared_mutex> lock{m_Lock}; |
| 507 | if (IsOpen()) |
| 508 | { |
| 509 | return LxError{LX_EINVAL}; |
| 510 | } |
| 511 | |
| 512 | if (m_Root->ReadOnly()) |
| 513 | { |
| 514 | return LxError{LX_EROFS}; |
| 515 | } |
| 516 | |
| 517 | // The specified gid is currently ignored. Supporting it would be possible, but it would be |
| 518 | // necessary to make sure that the user is a member of the specified group. |
| 519 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 520 | auto newFileName = ChildPathWithLockHeld(name); |
| 521 | auto file{util::OpenAt(m_Root->RootFd, newFileName, OpenFlagsToLinuxFlags(flags) | O_CREAT | O_NOFOLLOW, mode)}; |
| 522 | if (!file) |
| 523 | { |
| 524 | return file.Unexpected(); |
| 525 | } |
| 526 | |
| 527 | struct stat st; |
| 528 | int result = fstat(file->get(), &st); |
| 529 | if (result < 0) |
| 530 | { |
| 531 | return LxError{-errno}; |
| 532 | } |
| 533 | |
| 534 | m_FileName = std::move(newFileName); |
| 535 | m_Io = CoroutineIoIssuer(file->get()); |
| 536 | m_File = std::move(file.Get()); |
| 537 | m_Qid = StatToQid(st); |
| 538 | m_Device = st.st_dev; |
| 539 | return m_Qid; |
| 540 | } |
| 541 | |
| 542 | // Creates a subdirectory. |
| 543 | Expected<Qid> File::MkDir(std::string_view name, UINT32 mode, UINT32 /* gid */) |
| 544 | { |
| 545 | const auto newFileName = ChildPath(name); |
| 546 | |
| 547 | // The specified gid is currently ignored. Supporting it would be possible, but it would be |
| 548 | // necessary to make sure that the user is a member of the specified group. |
| 549 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 550 | int result = mkdirat(m_Root->RootFd, newFileName.c_str(), mode); |
| 551 | if (result < 0) |
| 552 | { |
| 553 | return LxError{-errno}; |
| 554 | } |
| 555 | |
| 556 | return GetFileQidByPath(m_Root->RootFd, newFileName); |
| 557 | } |
| 558 | |
| 559 | // Reads the contents of a directory, starting at the specified offset. |
| 560 | LX_INT File::ReadDir(UINT64 offset, SpanWriter& writer, bool includeAttributes) |
| 561 | { |
| 562 | if (!IsOpen()) |
| 563 | { |
| 564 | return LX_EBADF; |
| 565 | } |
| 566 | |
| 567 | // Acquire an exclusive lock to protect enumerator state. |
| 568 | std::lock_guard<std::shared_mutex> lock{m_Lock}; |
| 569 | if (!m_Enumerator) |
| 570 | { |
| 571 | m_Enumerator.reset(new DirectoryEnumerator(m_File.get())); |
| 572 | // The fd is now owned by the enumerator. |
| 573 | m_File.release(); |
| 574 | } |
| 575 | |
| 576 | m_Enumerator->Seek(offset); |
| 577 | |
| 578 | bool dirEntriesWritten = false; |
| 579 | for (;;) |
| 580 | { |
| 581 | auto entry = m_Enumerator->Next(); |
| 582 | if (entry == nullptr) |
| 583 | { |
| 584 | break; |
| 585 | } |
| 586 | |
| 587 | StatResult attributes; |
| 588 | StatResult* attributesToUse = nullptr; |
| 589 | if (includeAttributes) |
| 590 | { |
| 591 | attributesToUse = &attributes; |
| 592 | struct stat st; |
| 593 | const char* name = entry->d_name; |
| 594 | |
| 595 | // Return attributes of the directory for both . and .. |
| 596 | if (strcmp(name, ".") == 0 || strcmp(name, "..") == 0) |
| 597 | { |
| 598 | name = ""; |
| 599 | } |
| 600 | |
| 601 | int result = fstatat(m_Enumerator->Fd(), name, &st, AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH); |
| 602 | if (result < 0) |
| 603 | { |
| 604 | // Fill out basic attributes if real attributes can't be determined. |
| 605 | attributes = {}; |
| 606 | attributes.Mode = util::DirEntryTypeToMode(entry->d_type); |
| 607 | attributes.NLink = 1; |
| 608 | } |
| 609 | else |
| 610 | { |
| 611 | attributes.Mode = st.st_mode; |
| 612 | attributes.Uid = st.st_uid; |
| 613 | attributes.Gid = st.st_gid; |
| 614 | attributes.NLink = st.st_nlink; |
| 615 | attributes.RDev = st.st_rdev; |
| 616 | attributes.Size = st.st_size; |
| 617 | attributes.BlockSize = st.st_blksize; |
| 618 | attributes.Blocks = st.st_blocks; |
| 619 | attributes.AtimeSec = st.st_atim.tv_sec; |
| 620 | attributes.AtimeNsec = st.st_atim.tv_nsec; |
| 621 | attributes.MtimeSec = st.st_mtim.tv_sec; |
| 622 | attributes.MtimeNsec = st.st_mtim.tv_nsec; |
| 623 | attributes.CtimeSec = st.st_ctim.tv_sec; |
| 624 | attributes.CtimeNsec = st.st_ctim.tv_nsec; |
| 625 | } |
| 626 | } |
| 627 | |
| 628 | Qid qid{}; |
| 629 | qid.Path = entry->d_ino; |
| 630 | qid.Type = util::DirEntryTypeToQidType(entry->d_type); |
| 631 | if (!util::SpanWriteDirectoryEntry(writer, entry->d_name, qid, entry->d_off, entry->d_type, attributesToUse)) |
| 632 | { |
| 633 | if (!dirEntriesWritten) |
| 634 | { |
| 635 | return LX_EINVAL; |
| 636 | } |
| 637 | |
| 638 | break; |
| 639 | } |
| 640 | |
| 641 | dirEntriesWritten = true; |
| 642 | } |
| 643 | |
| 644 | return {}; |
| 645 | } |
| 646 | |
| 647 | // Reads the contents of an open file. |
| 648 | Task<Expected<UINT32>> File::Read(UINT64 offset, gsl::span<gsl::byte> buffer) |
| 649 | { |
| 650 | // No locking needed; once open, the file will not be closed until the |
| 651 | // object is destructed, and the caller holds a reference. |
| 652 | if (!m_File) |
| 653 | { |
| 654 | co_return LxError{LX_EBADF}; |
| 655 | } |
| 656 | |
| 657 | CancelToken token; |
| 658 | auto result = co_await ReadAsync(m_Io, offset, buffer, token); |
| 659 | if (result.Error != 0 && result.Error != LX_EOVERFLOW) |
| 660 | { |
| 661 | co_return LxError{result.Error}; |
| 662 | } |
| 663 | |
| 664 | co_return static_cast<UINT32>(result.BytesTransferred); |
| 665 | } |
| 666 | |
| 667 | // Writes to an open file. |
| 668 | Task<Expected<UINT32>> File::Write(UINT64 offset, gsl::span<const gsl::byte> buffer) |
| 669 | { |
| 670 | // Since the file could not have been opened for write on a read-only file |
| 671 | // system, there is no reason to check that here. |
| 672 | |
| 673 | // No locking needed; once open, the file will not be closed until the |
| 674 | // object is destructed, and the caller holds a reference. |
| 675 | if (!m_File) |
| 676 | { |
| 677 | co_return LxError{LX_EBADF}; |
| 678 | } |
| 679 | |
| 680 | CancelToken token; |
| 681 | auto result = co_await WriteAsync(m_Io, offset, buffer, token); |
| 682 | if (result.Error != 0) |
| 683 | { |
| 684 | co_return LxError{result.Error}; |
| 685 | } |
| 686 | |
| 687 | co_return result.BytesTransferred; |
| 688 | } |
| 689 | |
| 690 | // Unlinks a directory entry. |
| 691 | LX_INT File::UnlinkAt(std::string_view name, UINT32 flags) |
| 692 | { |
| 693 | if (m_Root->ReadOnly()) |
| 694 | { |
| 695 | return LX_EROFS; |
| 696 | } |
| 697 | |
| 698 | const auto fileName = ChildPath(name); |
| 699 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 700 | |
| 701 | // TODO: it's unclear whether this is the correct usage of the |
| 702 | // flags field. The Windows implementation unlinks either directory or |
| 703 | // file regardless of flags. |
| 704 | int result = unlinkat(m_Root->RootFd, fileName.c_str(), flags); |
| 705 | if (result < 0) |
| 706 | { |
| 707 | return -errno; |
| 708 | } |
| 709 | |
| 710 | return {}; |
| 711 | } |
| 712 | |
| 713 | // Removes the directory entry represented by the current fid. |
| 714 | LX_INT File::Remove() |
| 715 | { |
| 716 | if (m_Root->ReadOnly()) |
| 717 | { |
| 718 | return LX_EROFS; |
| 719 | } |
| 720 | |
| 721 | int flags = 0; |
| 722 | WI_SetFlagIf(flags, AT_REMOVEDIR, WI_IsFlagSet(m_Qid.Type, QidType::Directory)); |
| 723 | const std::string fileName = GetFileName(); |
| 724 | if (fileName.length() == 0) |
| 725 | { |
| 726 | // Can't unlink the root. |
| 727 | return LX_EPERM; |
| 728 | } |
| 729 | |
| 730 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 731 | const int result = unlinkat(m_Root->RootFd, fileName.c_str(), flags); |
| 732 | if (result < 0) |
| 733 | { |
| 734 | return -errno; |
| 735 | } |
| 736 | |
| 737 | return {}; |
| 738 | } |
| 739 | |
| 740 | // Gets a copy of the file name, taking the lock to retrieve it. |
| 741 | std::string File::GetFileName() const |
| 742 | { |
| 743 | std::shared_lock<std::shared_mutex> lock{m_Lock}; |
| 744 | return m_FileName; |
| 745 | } |
| 746 | |
| 747 | // Constructs a child path of the current path from a valid Linux path segment. |
| 748 | std::string File::ChildPath(std::string_view name) |
| 749 | { |
| 750 | auto result = GetFileName(); |
| 751 | AppendPath(result, name); |
| 752 | return result; |
| 753 | } |
| 754 | |
| 755 | std::string File::ChildPathWithLockHeld(std::string_view name) |
| 756 | { |
| 757 | std::string result{m_FileName}; |
| 758 | AppendPath(result, name); |
| 759 | return result; |
| 760 | } |
| 761 | |
| 762 | // Renames a directory entry. |
| 763 | LX_INT File::RenameAt(std::string_view oldName, Fid& newParent, std::string_view newName) |
| 764 | { |
| 765 | if (!newParent.IsFile() || !newParent.IsOnRoot(m_Root)) |
| 766 | { |
| 767 | return LX_EINVAL; |
| 768 | } |
| 769 | |
| 770 | if (m_Root->ReadOnly()) |
| 771 | { |
| 772 | return LX_EROFS; |
| 773 | } |
| 774 | |
| 775 | auto newParentFile = static_cast<File&>(newParent); |
| 776 | const auto oldPath = ChildPath(oldName); |
| 777 | const auto newPath = newParentFile.ChildPath(newName); |
| 778 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 779 | int result = renameat(m_Root->RootFd, oldPath.c_str(), m_Root->RootFd, newPath.c_str()); |
| 780 | if (result < 0) |
| 781 | { |
| 782 | return -errno; |
| 783 | } |
| 784 | |
| 785 | return {}; |
| 786 | } |
| 787 | |
| 788 | // Renames the current directory entry. |
| 789 | LX_INT File::Rename(Fid& newParent, std::string_view newName) |
| 790 | { |
| 791 | if (!newParent.IsFile() || !newParent.IsOnRoot(m_Root)) |
| 792 | { |
| 793 | return LX_EINVAL; |
| 794 | } |
| 795 | |
| 796 | if (m_Root->ReadOnly()) |
| 797 | { |
| 798 | return LX_EROFS; |
| 799 | } |
| 800 | |
| 801 | auto newParentFile = static_cast<File&>(newParent); |
| 802 | // Take an exclusive lock because the file name will be changed. |
| 803 | std::lock_guard<std::shared_mutex> lock{m_Lock}; |
| 804 | if (m_FileName.length() == 0) |
| 805 | { |
| 806 | // Can't rename the root. |
| 807 | return LX_EPERM; |
| 808 | } |
| 809 | |
| 810 | const auto oldPath = m_FileName; |
| 811 | auto newPath = newParentFile.ChildPath(newName); |
| 812 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 813 | int result = renameat(m_Root->RootFd, oldPath.c_str(), m_Root->RootFd, newPath.c_str()); |
| 814 | if (result < 0) |
| 815 | { |
| 816 | return -errno; |
| 817 | } |
| 818 | |
| 819 | m_FileName = newPath; |
| 820 | return {}; |
| 821 | } |
| 822 | |
| 823 | // Creates a symbolic link in a directory. |
| 824 | Expected<Qid> File::SymLink(std::string_view name, std::string_view target, UINT32 /* gid */) |
| 825 | { |
| 826 | if (m_Root->ReadOnly()) |
| 827 | { |
| 828 | return LxError{LX_EROFS}; |
| 829 | } |
| 830 | |
| 831 | // TODO: Gid is being ignored. |
| 832 | const auto linkName = ChildPath(name); |
| 833 | // Need a null-terminated string: |
| 834 | const std::string linkTarget{target.data(), target.size()}; |
| 835 | |
| 836 | // The specified gid is currently ignored. Supporting it would be possible, but it would be |
| 837 | // necessary to make sure that the user is a member of the specified group. |
| 838 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 839 | int result = symlinkat(linkTarget.c_str(), m_Root->RootFd, linkName.c_str()); |
| 840 | if (result < 0) |
| 841 | { |
| 842 | return LxError{-errno}; |
| 843 | } |
| 844 | |
| 845 | return GetFileQidByPath(m_Root->RootFd, linkName); |
| 846 | } |
| 847 | |
| 848 | // Reads the target of a symbolic link. |
| 849 | Expected<UINT32> File::ReadLink(gsl::span<char> name) |
| 850 | { |
| 851 | const auto fileName = GetFileName(); |
| 852 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 853 | ssize_t result = readlinkat(m_Root->RootFd, fileName.c_str(), name.data(), name.size()); |
| 854 | if (result < 0) |
| 855 | { |
| 856 | return LxError{-errno}; |
| 857 | } |
| 858 | |
| 859 | return result; |
| 860 | } |
| 861 | |
| 862 | // Creates a hard link in a directory to another file. |
| 863 | LX_INT File::Link(std::string_view newName, Fid& target) |
| 864 | { |
| 865 | if (!target.IsFile() || !target.IsOnRoot(m_Root)) |
| 866 | { |
| 867 | return LX_EINVAL; |
| 868 | } |
| 869 | |
| 870 | if (m_Root->ReadOnly()) |
| 871 | { |
| 872 | return LX_EROFS; |
| 873 | } |
| 874 | |
| 875 | const auto targetFile = static_cast<File&>(target); |
| 876 | |
| 877 | // Construct the new name relative to the share root. |
| 878 | const auto newLinkName = ChildPath(newName); |
| 879 | const auto targetName = targetFile.GetFileName(); |
| 880 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 881 | int result = linkat(m_Root->RootFd, targetName.c_str(), m_Root->RootFd, newLinkName.c_str(), 0); |
| 882 | if (result < 0) |
| 883 | { |
| 884 | return -errno; |
| 885 | } |
| 886 | |
| 887 | return {}; |
| 888 | } |
| 889 | |
| 890 | // Creates a device object in a directory. |
| 891 | Expected<Qid> File::MkNod(std::string_view name, UINT32 mode, UINT32 major, UINT32 minor, UINT32 gid) |
| 892 | { |
| 893 | if (m_Root->ReadOnly()) |
| 894 | { |
| 895 | return LxError{LX_EROFS}; |
| 896 | } |
| 897 | |
| 898 | const auto path = ChildPath(name); |
| 899 | |
| 900 | // The specified gid is currently ignored. Supporting it would be possible, but it would be |
| 901 | // necessary to make sure that the user is a member of the specified group. |
| 902 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 903 | int result = mknodat(m_Root->RootFd, path.c_str(), mode, makedev(major, minor)); |
| 904 | if (result < 0) |
| 905 | { |
| 906 | return LxError{-errno}; |
| 907 | } |
| 908 | |
| 909 | return GetFileQidByPath(m_Root->RootFd, path); |
| 910 | } |
| 911 | |
| 912 | // Flushes a file's buffers. |
| 913 | LX_INT File::Fsync() |
| 914 | { |
| 915 | if (!m_File) |
| 916 | { |
| 917 | return LX_EINVAL; |
| 918 | } |
| 919 | |
| 920 | int result = fsync(m_File.get()); |
| 921 | if (result < 0) |
| 922 | { |
| 923 | return -errno; |
| 924 | } |
| 925 | |
| 926 | return {}; |
| 927 | } |
| 928 | |
| 929 | // Retrieves the file system attributes. |
| 930 | Expected<StatFsResult> File::StatFs() |
| 931 | { |
| 932 | // Open the file because there is no statfsat. |
| 933 | auto file{OpenFile(O_PATH)}; |
| 934 | if (!file) |
| 935 | { |
| 936 | return file.Unexpected(); |
| 937 | } |
| 938 | |
| 939 | struct statfs statFs; |
| 940 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 941 | int result = fstatfs(file->get(), &statFs); |
| 942 | if (result < 0) |
| 943 | { |
| 944 | return LxError{-errno}; |
| 945 | } |
| 946 | |
| 947 | StatFsResult statFsResult; |
| 948 | statFsResult.Type = static_cast<UINT32>(statFs.f_type); |
| 949 | statFsResult.BlockSize = static_cast<UINT32>(statFs.f_bsize); |
| 950 | statFsResult.Blocks = statFs.f_blocks; |
| 951 | statFsResult.BlocksFree = statFs.f_bfree; |
| 952 | statFsResult.BlocksAvailable = statFs.f_bavail; |
| 953 | statFsResult.Files = statFs.f_files; |
| 954 | statFsResult.FilesFree = statFs.f_ffree; |
| 955 | statFsResult.NameLength = static_cast<UINT32>(statFs.f_namelen); |
| 956 | |
| 957 | static_assert(sizeof(statFsResult.FsId) == sizeof(statFs.f_fsid)); |
| 958 | // These two fields should be the same size (asserted above). |
| 959 | memcpy(&statFsResult.FsId, &statFs.f_fsid, sizeof(statFsResult.FsId)); |
| 960 | return statFsResult; |
| 961 | } |
| 962 | |
| 963 | // Locks a range of the file. |
| 964 | Expected<LockStatus> File::Lock(LockType, UINT32, UINT64, UINT64, UINT32, const std::string_view) |
| 965 | { |
| 966 | // The file has to be open for lock to work. |
| 967 | if (!IsOpen()) |
| 968 | { |
| 969 | return LxError{LX_EBADF}; |
| 970 | } |
| 971 | |
| 972 | // This implementation always returns success. The Linux kernel still |
| 973 | // provides proper file locking, and this call seems to only be used |
| 974 | // to check for server locking between multiple clients. That means a |
| 975 | // no-op implementation works for a single client. |
| 976 | // |
| 977 | // TODO: Implement server-side locks. |
| 978 | return LockStatus::Success; |
| 979 | } |
| 980 | |
| 981 | // Gets information about the current lock on the file. |
| 982 | Expected<std::tuple<LockType, UINT64, UINT64, UINT32, std::string_view>> File::GetLock( |
| 983 | LockType, UINT64 Start, UINT64 Length, UINT32 ProcId, const std::string_view ClientId) |
| 984 | { |
| 985 | // The file has to be open for getlock to work. |
| 986 | if (!IsOpen()) |
| 987 | { |
| 988 | return LxError{LX_EBADF}; |
| 989 | } |
| 990 | |
| 991 | // This implementation always returns unlocked, and echoes the rest of |
| 992 | // the values back to the client. The Linux kernel still provides |
| 993 | // proper file locking, and returns the correct information even if the |
| 994 | // server says unlocked. That means a no-op implementation works for a |
| 995 | // single client. |
| 996 | // |
| 997 | // TODO: Implement server-side locks. |
| 998 | return std::make_tuple(LockType::Unlock, Start, Length, ProcId, ClientId); |
| 999 | } |
| 1000 | |
| 1001 | // Created a new Fid representing an extended attribute. |
| 1002 | Expected<std::shared_ptr<XAttrBase>> File::XattrWalk(const std::string& name) |
| 1003 | { |
| 1004 | // N.B. There is no *xattrat or equivalent, so f*xattr must be used |
| 1005 | // to avoid constructing the full file name. However, f*xattr doesn't work |
| 1006 | // on file descriptors opened with O_PATH, so they can't be used on symlinks, |
| 1007 | // even though the various l*xattr functions do allow manipulating xattrs |
| 1008 | // on symlinks. This means there's no way to support xattrs on symlinks |
| 1009 | // without using the full file name, which is less than ideal. |
| 1010 | // TODO: Use a chroot environment to make this safer. |
| 1011 | auto path = util::GetFdPath(m_Root->RootFd); |
| 1012 | AppendPath(path, GetFileName()); |
| 1013 | std::shared_ptr<XAttrBase> xattr = std::make_shared<XAttr>(m_Root, path, name, XAttr::Access::Read); |
| 1014 | return xattr; |
| 1015 | } |
| 1016 | |
| 1017 | Expected<std::shared_ptr<XAttrBase>> File::XattrCreate(const std::string& name, UINT64 size, UINT32 flags) |
| 1018 | { |
| 1019 | if (m_Root->ReadOnly()) |
| 1020 | { |
| 1021 | return LxError{LX_EROFS}; |
| 1022 | } |
| 1023 | |
| 1024 | // Since the caller will end up replacing the original fid with the one |
| 1025 | // returned, make sure this wasn't an open fid. |
| 1026 | if (IsOpen()) |
| 1027 | { |
| 1028 | return LxError{LX_EINVAL}; |
| 1029 | } |
| 1030 | |
| 1031 | // See above for the reason for doing this. |
| 1032 | auto path = util::GetFdPath(m_Root->RootFd); |
| 1033 | AppendPath(path, GetFileName()); |
| 1034 | std::shared_ptr<XAttrBase> xattr = std::make_shared<XAttr>(m_Root, path, name, XAttr::Access::Write, size, flags); |
| 1035 | return xattr; |
| 1036 | } |
| 1037 | |
| 1038 | LX_INT File::Access(AccessFlags flags) |
| 1039 | { |
| 1040 | AccessFlags flagsWithoutDelete = flags; |
| 1041 | WI_ClearFlag(flagsWithoutDelete, AccessFlags::Delete); |
| 1042 | const auto name = GetFileName(); |
| 1043 | util::FsUserContext userContext{m_Root->Uid, m_Root->Gid, m_Root->Groups}; |
| 1044 | LX_INT result = util::AccessHelper(m_Root->RootFd, name, static_cast<int>(flagsWithoutDelete)); |
| 1045 | if (result < 0) |
| 1046 | { |
| 1047 | return result; |
| 1048 | } |
| 1049 | |
| 1050 | // No delete check requested? Done! |
| 1051 | if (!WI_IsFlagSet(flags, AccessFlags::Delete)) |
| 1052 | { |
| 1053 | return {}; |
| 1054 | } |
| 1055 | |
| 1056 | if (name.length() == 0) |
| 1057 | { |
| 1058 | // Can't delete the root. |
| 1059 | return LX_EACCES; |
| 1060 | } |
| 1061 | |
| 1062 | std::string parentPath; |
| 1063 | const auto index = name.find_last_of('/'); |
| 1064 | if (index != std::string::npos) |
| 1065 | { |
| 1066 | parentPath = name.substr(0, index); |
| 1067 | } |
| 1068 | |
| 1069 | // Check for write access to the parent. |
| 1070 | result = util::AccessHelper(m_Root->RootFd, parentPath, W_OK); |
| 1071 | if (result < 0) |
| 1072 | { |
| 1073 | return result; |
| 1074 | } |
| 1075 | |
| 1076 | // Get the parent's attributes. |
| 1077 | struct stat st; |
| 1078 | result = fstatat(m_Root->RootFd, parentPath.c_str(), &st, AT_EMPTY_PATH); |
| 1079 | if (result < 0) |
| 1080 | { |
| 1081 | return -errno; |
| 1082 | } |
| 1083 | |
| 1084 | // No sticky bit? Done! |
| 1085 | if (!WI_IsFlagSet(st.st_mode, S_ISVTX)) |
| 1086 | { |
| 1087 | return {}; |
| 1088 | } |
| 1089 | |
| 1090 | // Check if this process has CAP_FOWNER, which means it can bypass the |
| 1091 | // sticky bit. |
| 1092 | result = util::CheckFOwnerCapability(); |
| 1093 | if (result == 0) |
| 1094 | { |
| 1095 | return {}; |
| 1096 | } |
| 1097 | else if (result != LX_EPERM) |
| 1098 | { |
| 1099 | return result; |
| 1100 | } |
| 1101 | |
| 1102 | // Check for ownership of the parent directory. |
| 1103 | uid_t uid = geteuid(); |
| 1104 | if (uid == st.st_uid) |
| 1105 | { |
| 1106 | return {}; |
| 1107 | } |
| 1108 | |
| 1109 | // Check for ownership of the child. |
| 1110 | result = fstatat(m_Root->RootFd, name.c_str(), &st, AT_EMPTY_PATH); |
| 1111 | if (result < 0) |
| 1112 | { |
| 1113 | return -errno; |
| 1114 | } |
| 1115 | |
| 1116 | if (uid == st.st_uid) |
| 1117 | { |
| 1118 | return {}; |
| 1119 | } |
| 1120 | |
| 1121 | // Stick bit checks failed. |
| 1122 | return LX_EACCES; |
| 1123 | } |
| 1124 | |
| 1125 | std::shared_ptr<Fid> File::Clone() const |
| 1126 | { |
| 1127 | // Requires the lock to protect the file name. |
| 1128 | std::shared_lock<std::shared_mutex> lock{m_Lock}; |
| 1129 | return std::make_shared<File>(*this); |
| 1130 | } |
| 1131 | |
| 1132 | bool File::IsOpen() const |
| 1133 | { |
| 1134 | return bool{m_File} || m_Enumerator; |
| 1135 | } |
| 1136 | |
| 1137 | bool File::IsFile() const |
| 1138 | { |
| 1139 | return true; |
| 1140 | } |
| 1141 | |
| 1142 | Qid File::GetQid() const |
| 1143 | { |
| 1144 | return m_Qid; |
| 1145 | } |
| 1146 | |
| 1147 | } // namespace p9fs |