Inode.cpp 11 KB

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  1. /*
  2. * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
  3. * Copyright (c) 2021, sin-ack <sin-ack@protonmail.com>
  4. *
  5. * SPDX-License-Identifier: BSD-2-Clause
  6. */
  7. #include <AK/NonnullRefPtrVector.h>
  8. #include <AK/Singleton.h>
  9. #include <AK/StringView.h>
  10. #include <Kernel/API/InodeWatcherEvent.h>
  11. #include <Kernel/FileSystem/Custody.h>
  12. #include <Kernel/FileSystem/Inode.h>
  13. #include <Kernel/FileSystem/InodeWatcher.h>
  14. #include <Kernel/FileSystem/OpenFileDescription.h>
  15. #include <Kernel/FileSystem/VirtualFileSystem.h>
  16. #include <Kernel/KBufferBuilder.h>
  17. #include <Kernel/Memory/SharedInodeVMObject.h>
  18. #include <Kernel/Net/LocalSocket.h>
  19. #include <Kernel/Process.h>
  20. namespace Kernel {
  21. static Singleton<SpinlockProtected<Inode::AllInstancesList>> s_all_instances;
  22. SpinlockProtected<Inode::AllInstancesList>& Inode::all_instances()
  23. {
  24. return s_all_instances;
  25. }
  26. void Inode::sync_all()
  27. {
  28. NonnullRefPtrVector<Inode, 32> inodes;
  29. Inode::all_instances().with([&](auto& all_inodes) {
  30. for (auto& inode : all_inodes) {
  31. if (inode.is_metadata_dirty())
  32. inodes.append(inode);
  33. }
  34. });
  35. for (auto& inode : inodes) {
  36. VERIFY(inode.is_metadata_dirty());
  37. (void)inode.flush_metadata();
  38. }
  39. }
  40. void Inode::sync()
  41. {
  42. if (is_metadata_dirty())
  43. (void)flush_metadata();
  44. fs().flush_writes();
  45. }
  46. ErrorOr<NonnullOwnPtr<KBuffer>> Inode::read_entire(OpenFileDescription* description) const
  47. {
  48. auto builder = TRY(KBufferBuilder::try_create());
  49. u8 buffer[4096];
  50. off_t offset = 0;
  51. for (;;) {
  52. auto buf = UserOrKernelBuffer::for_kernel_buffer(buffer);
  53. auto nread = TRY(read_bytes(offset, sizeof(buffer), buf, description));
  54. VERIFY(nread <= sizeof(buffer));
  55. if (nread == 0)
  56. break;
  57. TRY(builder.append((const char*)buffer, nread));
  58. offset += nread;
  59. if (nread < sizeof(buffer))
  60. break;
  61. }
  62. auto entire_file = builder.build();
  63. if (!entire_file)
  64. return ENOMEM;
  65. return entire_file.release_nonnull();
  66. }
  67. ErrorOr<NonnullRefPtr<Custody>> Inode::resolve_as_link(Custody& base, RefPtr<Custody>* out_parent, int options, int symlink_recursion_level) const
  68. {
  69. // The default implementation simply treats the stored
  70. // contents as a path and resolves that. That is, it
  71. // behaves exactly how you would expect a symlink to work.
  72. auto contents = TRY(read_entire());
  73. return VirtualFileSystem::the().resolve_path(StringView { contents->bytes() }, base, out_parent, options, symlink_recursion_level);
  74. }
  75. Inode::Inode(FileSystem& fs, InodeIndex index)
  76. : m_file_system(fs)
  77. , m_index(index)
  78. {
  79. Inode::all_instances().with([&](auto& all_inodes) { all_inodes.append(*this); });
  80. }
  81. Inode::~Inode()
  82. {
  83. m_watchers.for_each([&](auto& watcher) {
  84. watcher->unregister_by_inode({}, identifier());
  85. });
  86. }
  87. void Inode::will_be_destroyed()
  88. {
  89. MutexLocker locker(m_inode_lock);
  90. if (m_metadata_dirty)
  91. (void)flush_metadata();
  92. }
  93. ErrorOr<void> Inode::set_atime(time_t)
  94. {
  95. return ENOTIMPL;
  96. }
  97. ErrorOr<void> Inode::set_ctime(time_t)
  98. {
  99. return ENOTIMPL;
  100. }
  101. ErrorOr<void> Inode::set_mtime(time_t)
  102. {
  103. return ENOTIMPL;
  104. }
  105. ErrorOr<void> Inode::increment_link_count()
  106. {
  107. return ENOTIMPL;
  108. }
  109. ErrorOr<void> Inode::decrement_link_count()
  110. {
  111. return ENOTIMPL;
  112. }
  113. void Inode::set_shared_vmobject(Memory::SharedInodeVMObject& vmobject)
  114. {
  115. MutexLocker locker(m_inode_lock);
  116. m_shared_vmobject = vmobject;
  117. }
  118. RefPtr<LocalSocket> Inode::bound_socket() const
  119. {
  120. return m_bound_socket;
  121. }
  122. bool Inode::bind_socket(LocalSocket& socket)
  123. {
  124. MutexLocker locker(m_inode_lock);
  125. if (m_bound_socket)
  126. return false;
  127. m_bound_socket = socket;
  128. return true;
  129. }
  130. bool Inode::unbind_socket()
  131. {
  132. MutexLocker locker(m_inode_lock);
  133. if (!m_bound_socket)
  134. return false;
  135. m_bound_socket = nullptr;
  136. return true;
  137. }
  138. ErrorOr<void> Inode::register_watcher(Badge<InodeWatcher>, InodeWatcher& watcher)
  139. {
  140. return m_watchers.with([&](auto& watchers) -> ErrorOr<void> {
  141. VERIFY(!watchers.contains(&watcher));
  142. TRY(watchers.try_set(&watcher));
  143. return {};
  144. });
  145. }
  146. void Inode::unregister_watcher(Badge<InodeWatcher>, InodeWatcher& watcher)
  147. {
  148. m_watchers.with([&](auto& watchers) {
  149. VERIFY(watchers.contains(&watcher));
  150. watchers.remove(&watcher);
  151. });
  152. }
  153. ErrorOr<NonnullRefPtr<FIFO>> Inode::fifo()
  154. {
  155. MutexLocker locker(m_inode_lock);
  156. VERIFY(metadata().is_fifo());
  157. // FIXME: Release m_fifo when it is closed by all readers and writers
  158. if (!m_fifo)
  159. m_fifo = TRY(FIFO::try_create(metadata().uid));
  160. return NonnullRefPtr { *m_fifo };
  161. }
  162. void Inode::set_metadata_dirty(bool metadata_dirty)
  163. {
  164. MutexLocker locker(m_inode_lock);
  165. if (metadata_dirty) {
  166. // Sanity check.
  167. VERIFY(!fs().is_readonly());
  168. }
  169. if (m_metadata_dirty == metadata_dirty)
  170. return;
  171. m_metadata_dirty = metadata_dirty;
  172. if (m_metadata_dirty) {
  173. // FIXME: Maybe we should hook into modification events somewhere else, I'm not sure where.
  174. // We don't always end up on this particular code path, for instance when writing to an ext2fs file.
  175. m_watchers.for_each([&](auto& watcher) {
  176. watcher->notify_inode_event({}, identifier(), InodeWatcherEvent::Type::MetadataModified);
  177. });
  178. }
  179. }
  180. void Inode::did_add_child(InodeIdentifier, StringView name)
  181. {
  182. m_watchers.for_each([&](auto& watcher) {
  183. watcher->notify_inode_event({}, identifier(), InodeWatcherEvent::Type::ChildCreated, name);
  184. });
  185. }
  186. void Inode::did_remove_child(InodeIdentifier, StringView name)
  187. {
  188. if (name == "." || name == "..") {
  189. // These are just aliases and are not interesting to userspace.
  190. return;
  191. }
  192. m_watchers.for_each([&](auto& watcher) {
  193. watcher->notify_inode_event({}, identifier(), InodeWatcherEvent::Type::ChildDeleted, name);
  194. });
  195. }
  196. void Inode::did_modify_contents()
  197. {
  198. m_watchers.for_each([&](auto& watcher) {
  199. watcher->notify_inode_event({}, identifier(), InodeWatcherEvent::Type::ContentModified);
  200. });
  201. }
  202. void Inode::did_delete_self()
  203. {
  204. m_watchers.for_each([&](auto& watcher) {
  205. watcher->notify_inode_event({}, identifier(), InodeWatcherEvent::Type::Deleted);
  206. });
  207. }
  208. ErrorOr<void> Inode::prepare_to_write_data()
  209. {
  210. // FIXME: It's a poor design that filesystems are expected to call this before writing out data.
  211. // We should funnel everything through an interface at the VirtualFileSystem layer so this can happen from a single place.
  212. MutexLocker locker(m_inode_lock);
  213. if (fs().is_readonly())
  214. return EROFS;
  215. auto metadata = this->metadata();
  216. if (metadata.is_setuid() || metadata.is_setgid()) {
  217. dbgln("Inode::prepare_to_write_data(): Stripping SUID/SGID bits from {}", identifier());
  218. return chmod(metadata.mode & ~(04000 | 02000));
  219. }
  220. return {};
  221. }
  222. RefPtr<Memory::SharedInodeVMObject> Inode::shared_vmobject() const
  223. {
  224. MutexLocker locker(m_inode_lock);
  225. return m_shared_vmobject.strong_ref();
  226. }
  227. template<typename T>
  228. static inline bool range_overlap(T start1, T len1, T start2, T len2)
  229. {
  230. return ((start1 < start2 + len2) || len2 == 0) && ((start2 < start1 + len1) || len1 == 0);
  231. }
  232. static inline ErrorOr<void> normalize_flock(OpenFileDescription const& description, flock& lock)
  233. {
  234. off_t start;
  235. switch (lock.l_whence) {
  236. case SEEK_SET:
  237. start = lock.l_start;
  238. break;
  239. case SEEK_CUR:
  240. start = description.offset() + lock.l_start;
  241. break;
  242. case SEEK_END:
  243. // FIXME: Implement SEEK_END and negative lengths.
  244. return ENOTSUP;
  245. default:
  246. return EINVAL;
  247. }
  248. lock = { lock.l_type, SEEK_SET, start, lock.l_len, 0 };
  249. return {};
  250. }
  251. ErrorOr<void> Inode::can_apply_flock(OpenFileDescription const& description, flock const& new_lock) const
  252. {
  253. VERIFY(new_lock.l_whence == SEEK_SET);
  254. return m_flocks.with([&](auto& flocks) -> ErrorOr<void> {
  255. if (new_lock.l_type == F_UNLCK) {
  256. for (auto const& lock : flocks) {
  257. if (&description == lock.owner && lock.start == new_lock.l_start && lock.len == new_lock.l_len)
  258. return {};
  259. }
  260. return EINVAL;
  261. }
  262. for (auto const& lock : flocks) {
  263. if (!range_overlap(lock.start, lock.len, new_lock.l_start, new_lock.l_len))
  264. continue;
  265. if (new_lock.l_type == F_RDLCK && lock.type == F_WRLCK)
  266. return EAGAIN;
  267. if (new_lock.l_type == F_WRLCK)
  268. return EAGAIN;
  269. }
  270. return {};
  271. });
  272. }
  273. ErrorOr<void> Inode::apply_flock(Process const& process, OpenFileDescription const& description, Userspace<flock const*> input_lock)
  274. {
  275. auto new_lock = TRY(copy_typed_from_user(input_lock));
  276. TRY(normalize_flock(description, new_lock));
  277. return m_flocks.with([&](auto& flocks) -> ErrorOr<void> {
  278. TRY(can_apply_flock(description, new_lock));
  279. if (new_lock.l_type == F_UNLCK) {
  280. for (size_t i = 0; i < flocks.size(); ++i) {
  281. if (&description == flocks[i].owner && flocks[i].start == new_lock.l_start && flocks[i].len == new_lock.l_len) {
  282. flocks.remove(i);
  283. return {};
  284. }
  285. }
  286. return EINVAL;
  287. }
  288. TRY(flocks.try_append(Flock { new_lock.l_start, new_lock.l_len, &description, process.pid().value(), new_lock.l_type }));
  289. return {};
  290. });
  291. }
  292. ErrorOr<void> Inode::get_flock(OpenFileDescription const& description, Userspace<flock*> reference_lock) const
  293. {
  294. flock lookup = {};
  295. TRY(copy_from_user(&lookup, reference_lock));
  296. TRY(normalize_flock(description, lookup));
  297. return m_flocks.with([&](auto& flocks) {
  298. for (auto const& lock : flocks) {
  299. if (!range_overlap(lock.start, lock.len, lookup.l_start, lookup.l_len))
  300. continue;
  301. if ((lookup.l_type == F_RDLCK && lock.type == F_WRLCK) || lookup.l_type == F_WRLCK) {
  302. lookup = { lock.type, SEEK_SET, lock.start, lock.len, lock.pid };
  303. return copy_to_user(reference_lock, &lookup);
  304. }
  305. }
  306. lookup.l_type = F_UNLCK;
  307. return copy_to_user(reference_lock, &lookup);
  308. });
  309. }
  310. void Inode::remove_flocks_for_description(OpenFileDescription const& description)
  311. {
  312. m_flocks.with([&](auto& flocks) {
  313. flocks.remove_all_matching([&](auto& entry) { return entry.owner == &description; });
  314. });
  315. }
  316. bool Inode::has_watchers() const
  317. {
  318. return !m_watchers.with([&](auto& watchers) { return watchers.is_empty(); });
  319. }
  320. }