jcs.org
Serenity Operating System
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
8#pragma once
9
10#include <AK/Error.h>
11#include <AK/Function.h>
12#include <AK/HashTable.h>
13#include <AK/IntrusiveList.h>
14#include <Kernel/FileSystem/FIFO.h>
15#include <Kernel/FileSystem/FileSystem.h>
16#include <Kernel/FileSystem/InodeIdentifier.h>
17#include <Kernel/FileSystem/InodeMetadata.h>
18#include <Kernel/Forward.h>
19#include <Kernel/Library/ListedRefCounted.h>
20#include <Kernel/Library/LockWeakPtr.h>
21#include <Kernel/Locking/Mutex.h>
22#include <Kernel/Memory/SharedInodeVMObject.h>
23
24namespace Kernel {
25
26enum class ShouldBlock {
27 No = 0,
28 Yes = 1
29};
30
31class Inode : public ListedRefCounted<Inode, LockType::Spinlock>
32 , public LockWeakable<Inode> {
33 friend class VirtualFileSystem;
34 friend class FileSystem;
35 friend class InodeFile;
36
37public:
38 virtual ~Inode();
39
40 virtual void remove_from_secondary_lists() { }
41
42 FileSystem& fs() { return m_file_system; }
43 FileSystem const& fs() const { return m_file_system; }
44 FileSystemID fsid() const { return m_file_system.fsid(); }
45 InodeIndex index() const { return m_index; }
46
47 size_t size() const { return metadata().size; }
48 bool is_symlink() const { return metadata().is_symlink(); }
49 bool is_directory() const { return metadata().is_directory(); }
50 bool is_character_device() const { return metadata().is_character_device(); }
51 mode_t mode() const { return metadata().mode; }
52
53 InodeIdentifier identifier() const { return { fsid(), index() }; }
54 virtual InodeMetadata metadata() const = 0;
55
56 ErrorOr<NonnullOwnPtr<KBuffer>> read_entire(OpenFileDescription* = nullptr) const;
57
58 ErrorOr<size_t> write_bytes(off_t, size_t, UserOrKernelBuffer const& data, OpenFileDescription*);
59 ErrorOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const;
60
61 virtual ErrorOr<void> attach(OpenFileDescription&) { return {}; }
62 virtual void detach(OpenFileDescription&) { }
63 virtual void did_seek(OpenFileDescription&, off_t) { }
64 virtual ErrorOr<void> traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>) const = 0;
65 virtual ErrorOr<NonnullRefPtr<Inode>> lookup(StringView name) = 0;
66 virtual ErrorOr<NonnullRefPtr<Inode>> create_child(StringView name, mode_t, dev_t, UserID, GroupID) = 0;
67 virtual ErrorOr<void> add_child(Inode&, StringView name, mode_t) = 0;
68 virtual ErrorOr<void> remove_child(StringView name) = 0;
69 /// Replace child atomically, incrementing the link count of the replacement
70 /// inode and decrementing the older inode's.
71 virtual ErrorOr<void> replace_child(StringView name, Inode&) = 0;
72 virtual ErrorOr<void> chmod(mode_t) = 0;
73 virtual ErrorOr<void> chown(UserID, GroupID) = 0;
74 virtual ErrorOr<void> truncate(u64) { return {}; }
75
76 ErrorOr<NonnullRefPtr<Custody>> resolve_as_link(Credentials const&, Custody& base, RefPtr<Custody>* out_parent, int options, int symlink_recursion_level) const;
77
78 virtual ErrorOr<int> get_block_address(int) { return ENOTSUP; }
79
80 LockRefPtr<LocalSocket> bound_socket() const;
81 bool bind_socket(LocalSocket&);
82 bool unbind_socket();
83
84 bool is_metadata_dirty() const { return m_metadata_dirty; }
85
86 virtual ErrorOr<void> update_timestamps(Optional<Time> atime, Optional<Time> ctime, Optional<Time> mtime);
87 virtual ErrorOr<void> increment_link_count();
88 virtual ErrorOr<void> decrement_link_count();
89
90 virtual ErrorOr<void> flush_metadata() = 0;
91
92 void will_be_destroyed();
93
94 ErrorOr<void> set_shared_vmobject(Memory::SharedInodeVMObject&);
95 LockRefPtr<Memory::SharedInodeVMObject> shared_vmobject() const;
96
97 static void sync_all();
98 void sync();
99
100 bool has_watchers() const;
101
102 ErrorOr<void> register_watcher(Badge<InodeWatcher>, InodeWatcher&);
103 void unregister_watcher(Badge<InodeWatcher>, InodeWatcher&);
104
105 ErrorOr<NonnullRefPtr<FIFO>> fifo();
106
107 bool can_apply_flock(flock const&, Optional<OpenFileDescription const&> = {}) const;
108 ErrorOr<void> apply_flock(Process const&, OpenFileDescription const&, Userspace<flock const*>, ShouldBlock);
109 ErrorOr<void> get_flock(OpenFileDescription const&, Userspace<flock*>) const;
110 void remove_flocks_for_description(OpenFileDescription const&);
111 Thread::FlockBlockerSet& flock_blocker_set() { return m_flock_blocker_set; };
112
113protected:
114 Inode(FileSystem&, InodeIndex);
115 void set_metadata_dirty(bool);
116 ErrorOr<void> prepare_to_write_data();
117
118 void did_add_child(InodeIdentifier child_id, StringView);
119 void did_remove_child(InodeIdentifier child_id, StringView);
120 void did_modify_contents();
121 void did_delete_self();
122
123 mutable Mutex m_inode_lock { "Inode"sv };
124
125 virtual ErrorOr<size_t> write_bytes_locked(off_t, size_t, UserOrKernelBuffer const& data, OpenFileDescription*) = 0;
126 virtual ErrorOr<size_t> read_bytes_locked(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const = 0;
127
128private:
129 ErrorOr<bool> try_apply_flock(Process const&, OpenFileDescription const&, flock const&);
130
131 FileSystem& m_file_system;
132 InodeIndex m_index { 0 };
133 LockWeakPtr<Memory::SharedInodeVMObject> m_shared_vmobject;
134 LockWeakPtr<LocalSocket> m_bound_socket;
135 SpinlockProtected<HashTable<InodeWatcher*>, LockRank::None> m_watchers {};
136 bool m_metadata_dirty { false };
137 RefPtr<FIFO> m_fifo;
138 IntrusiveListNode<Inode> m_inode_list_node;
139
140 struct Flock {
141 off_t start;
142 off_t len;
143 OpenFileDescription const* owner;
144 pid_t pid;
145 short type;
146 };
147
148 Thread::FlockBlockerSet m_flock_blocker_set;
149 SpinlockProtected<Vector<Flock>, LockRank::None> m_flocks {};
150
151public:
152 using AllInstancesList = IntrusiveList<&Inode::m_inode_list_node>;
153 static SpinlockProtected<Inode::AllInstancesList, LockRank::None>& all_instances();
154};
155
156}