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Serenity Operating System
1/*
2 * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#pragma once
28
29#include <AK/HashMap.h>
30#include <AK/Optional.h>
31#include <Kernel/FileSystem/FileSystem.h>
32#include <Kernel/FileSystem/Inode.h>
33#include <Kernel/KBuffer.h>
34
35namespace Kernel {
36
37class TmpFSInode;
38
39class TmpFS final : public FS {
40 friend class TmpFSInode;
41
42public:
43 virtual ~TmpFS() override;
44 static NonnullRefPtr<TmpFS> create();
45 virtual bool initialize() override;
46
47 virtual const char* class_name() const override { return "TmpFS"; }
48
49 virtual bool supports_watchers() const override { return true; }
50
51 virtual InodeIdentifier root_inode() const override;
52 virtual RefPtr<Inode> get_inode(InodeIdentifier) const override;
53
54 virtual KResultOr<NonnullRefPtr<Inode>> create_inode(InodeIdentifier parent_id, const String& name, mode_t, off_t size, dev_t, uid_t, gid_t) override;
55 virtual KResult create_directory(InodeIdentifier parent_id, const String& name, mode_t, uid_t, gid_t) override;
56
57private:
58 TmpFS();
59
60 RefPtr<TmpFSInode> m_root_inode;
61
62 HashMap<unsigned, NonnullRefPtr<TmpFSInode>> m_inodes;
63 void register_inode(TmpFSInode&);
64 void unregister_inode(InodeIdentifier);
65
66 unsigned m_next_inode_index { 1 };
67 unsigned next_inode_index();
68};
69
70class TmpFSInode final : public Inode {
71 friend class TmpFS;
72
73public:
74 virtual ~TmpFSInode() override;
75
76 TmpFS& fs() { return static_cast<TmpFS&>(Inode::fs()); }
77 const TmpFS& fs() const { return static_cast<const TmpFS&>(Inode::fs()); }
78
79 // ^Inode
80 virtual ssize_t read_bytes(off_t, ssize_t, u8* buffer, FileDescription*) const override;
81 virtual InodeMetadata metadata() const override;
82 virtual bool traverse_as_directory(Function<bool(const FS::DirectoryEntry&)>) const override;
83 virtual RefPtr<Inode> lookup(StringView name) override;
84 virtual void flush_metadata() override;
85 virtual ssize_t write_bytes(off_t, ssize_t, const u8* buffer, FileDescription*) override;
86 virtual KResult add_child(InodeIdentifier child_id, const StringView& name, mode_t) override;
87 virtual KResult remove_child(const StringView& name) override;
88 virtual size_t directory_entry_count() const override;
89 virtual KResult chmod(mode_t) override;
90 virtual KResult chown(uid_t, gid_t) override;
91 virtual KResult truncate(u64) override;
92 virtual int set_atime(time_t) override;
93 virtual int set_ctime(time_t) override;
94 virtual int set_mtime(time_t) override;
95 virtual void one_ref_left() override;
96
97private:
98 TmpFSInode(TmpFS& fs, InodeMetadata metadata, InodeIdentifier parent);
99 static NonnullRefPtr<TmpFSInode> create(TmpFS&, InodeMetadata metadata, InodeIdentifier parent);
100 static NonnullRefPtr<TmpFSInode> create_root(TmpFS&);
101
102 InodeMetadata m_metadata;
103 InodeIdentifier m_parent;
104
105 Optional<KBuffer> m_content;
106 struct Child {
107 FS::DirectoryEntry entry;
108 NonnullRefPtr<TmpFSInode> inode;
109 };
110 HashMap<String, Child> m_children;
111};
112
113}