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Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@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/RefCounted.h>
30#include <AK/RefPtr.h>
31#include <AK/String.h>
32#include <Kernel/FileSystem/InodeIdentifier.h>
33#include <Kernel/KResult.h>
34#include <Kernel/Lock.h>
35#include <Kernel/UnixTypes.h>
36
37namespace Kernel {
38
39static const u32 mepoch = 476763780;
40
41class Inode;
42class FileDescription;
43class LocalSocket;
44class VMObject;
45
46class FS : public RefCounted<FS> {
47 friend class Inode;
48
49public:
50 virtual ~FS();
51
52 unsigned fsid() const { return m_fsid; }
53 static FS* from_fsid(u32);
54 static void sync();
55 static void lock_all();
56
57 virtual bool initialize() = 0;
58 virtual const char* class_name() const = 0;
59 virtual InodeIdentifier root_inode() const = 0;
60 virtual bool supports_watchers() const { return false; }
61
62 bool is_readonly() const { return m_readonly; }
63
64 virtual unsigned total_block_count() const { return 0; }
65 virtual unsigned free_block_count() const { return 0; }
66 virtual unsigned total_inode_count() const { return 0; }
67 virtual unsigned free_inode_count() const { return 0; }
68
69 virtual KResult prepare_to_unmount() const { return KSuccess; }
70
71 // FIXME: This data structure is very clunky and unpleasant. Replace it with something nicer.
72 struct DirectoryEntry {
73 DirectoryEntry(const char* name, InodeIdentifier, u8 file_type);
74 DirectoryEntry(const char* name, size_t name_length, InodeIdentifier, u8 file_type);
75 char name[256];
76 size_t name_length { 0 };
77 InodeIdentifier inode;
78 u8 file_type { 0 };
79 };
80
81 virtual KResultOr<NonnullRefPtr<Inode>> create_inode(InodeIdentifier parent_id, const String& name, mode_t, off_t size, dev_t, uid_t, gid_t) = 0;
82 virtual KResult create_directory(InodeIdentifier parent_inode, const String& name, mode_t, uid_t, gid_t) = 0;
83
84 virtual RefPtr<Inode> get_inode(InodeIdentifier) const = 0;
85
86 virtual void flush_writes() {}
87
88 int block_size() const { return m_block_size; }
89
90 virtual bool is_file_backed() const { return false; }
91
92protected:
93 FS();
94
95 void set_block_size(int);
96
97 mutable Lock m_lock { "FS" };
98
99private:
100 unsigned m_fsid { 0 };
101 int m_block_size { 0 };
102 bool m_readonly { false };
103};
104
105inline FS* InodeIdentifier::fs()
106{
107 return FS::from_fsid(m_fsid);
108}
109
110inline const FS* InodeIdentifier::fs() const
111{
112 return FS::from_fsid(m_fsid);
113}
114
115inline bool InodeIdentifier::is_root_inode() const
116{
117 return (*this) == fs()->root_inode();
118}
119
120}
121
122namespace AK {
123
124template<>
125struct Traits<Kernel::InodeIdentifier> : public GenericTraits<Kernel::InodeIdentifier> {
126 static unsigned hash(const Kernel::InodeIdentifier& inode) { return pair_int_hash(inode.fsid(), inode.index()); }
127};
128
129}