jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#include <AK/RefPtr.h>
8#include <AK/Singleton.h>
9#include <AK/StringBuilder.h>
10#include <AK/StringView.h>
11#include <AK/Vector.h>
12#include <Kernel/FileSystem/Custody.h>
13#include <Kernel/FileSystem/Inode.h>
14
15namespace Kernel {
16
17static Singleton<SpinlockProtected<Custody::AllCustodiesList, LockRank::None>> s_all_instances;
18
19SpinlockProtected<Custody::AllCustodiesList, LockRank::None>& Custody::all_instances()
20{
21 return s_all_instances;
22}
23
24ErrorOr<NonnullRefPtr<Custody>> Custody::try_create(Custody* parent, StringView name, Inode& inode, int mount_flags)
25{
26 return all_instances().with([&](auto& all_custodies) -> ErrorOr<NonnullRefPtr<Custody>> {
27 for (Custody& custody : all_custodies) {
28 if (custody.parent() == parent
29 && custody.name() == name
30 && &custody.inode() == &inode
31 && custody.mount_flags() == mount_flags) {
32 return NonnullRefPtr { custody };
33 }
34 }
35
36 auto name_kstring = TRY(KString::try_create(name));
37 auto custody = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) Custody(parent, move(name_kstring), inode, mount_flags)));
38 all_custodies.prepend(*custody);
39 return custody;
40 });
41}
42
43Custody::Custody(Custody* parent, NonnullOwnPtr<KString> name, Inode& inode, int mount_flags)
44 : m_parent(parent)
45 , m_name(move(name))
46 , m_inode(inode)
47 , m_mount_flags(mount_flags)
48{
49}
50
51Custody::~Custody() = default;
52
53ErrorOr<NonnullOwnPtr<KString>> Custody::try_serialize_absolute_path() const
54{
55 if (!parent())
56 return KString::try_create("/"sv);
57
58 Vector<Custody const*, 32> custody_chain;
59 size_t path_length = 0;
60 for (auto const* custody = this; custody; custody = custody->parent()) {
61 TRY(custody_chain.try_append(custody));
62 path_length += custody->m_name->length() + 1;
63 }
64 VERIFY(path_length > 0);
65
66 char* buffer;
67 auto string = TRY(KString::try_create_uninitialized(path_length - 1, buffer));
68 size_t string_index = 0;
69 for (size_t custody_index = custody_chain.size() - 1; custody_index > 0; --custody_index) {
70 buffer[string_index] = '/';
71 ++string_index;
72 auto const& custody_name = *custody_chain[custody_index - 1]->m_name;
73 __builtin_memcpy(buffer + string_index, custody_name.characters(), custody_name.length());
74 string_index += custody_name.length();
75 }
76 VERIFY(string->length() == string_index);
77 buffer[string_index] = 0;
78 return string;
79}
80
81bool Custody::is_readonly() const
82{
83 if (m_mount_flags & MS_RDONLY)
84 return true;
85
86 return m_inode->fs().is_readonly();
87}
88
89}