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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#include <AK/NonnullRefPtrVector.h>
28#include <AK/StringBuilder.h>
29#include <AK/StringView.h>
30#include <Kernel/FileSystem/Custody.h>
31#include <Kernel/FileSystem/Inode.h>
32#include <Kernel/FileSystem/InodeWatcher.h>
33#include <Kernel/FileSystem/VirtualFileSystem.h>
34#include <Kernel/Net/LocalSocket.h>
35#include <Kernel/VM/SharedInodeVMObject.h>
36
37namespace Kernel {
38
39InlineLinkedList<Inode>& all_inodes()
40{
41 static InlineLinkedList<Inode>* list;
42 if (!list)
43 list = new InlineLinkedList<Inode>;
44 return *list;
45}
46
47void Inode::sync()
48{
49 NonnullRefPtrVector<Inode, 32> inodes;
50 {
51 InterruptDisabler disabler;
52 for (auto& inode : all_inodes()) {
53 if (inode.is_metadata_dirty())
54 inodes.append(inode);
55 }
56 }
57
58 for (auto& inode : inodes) {
59 ASSERT(inode.is_metadata_dirty());
60 inode.flush_metadata();
61 }
62}
63
64ByteBuffer Inode::read_entire(FileDescription* descriptor) const
65{
66 size_t initial_size = metadata().size ? metadata().size : 4096;
67 StringBuilder builder(initial_size);
68
69 ssize_t nread;
70 u8 buffer[4096];
71 off_t offset = 0;
72 for (;;) {
73 nread = read_bytes(offset, sizeof(buffer), buffer, descriptor);
74 ASSERT(nread <= (ssize_t)sizeof(buffer));
75 if (nread <= 0)
76 break;
77 builder.append((const char*)buffer, nread);
78 offset += nread;
79 if (nread < (ssize_t)sizeof(buffer))
80 break;
81 }
82 if (nread < 0) {
83 klog() << "Inode::read_entire: ERROR: " << nread;
84 return nullptr;
85 }
86
87 return builder.to_byte_buffer();
88}
89
90KResultOr<NonnullRefPtr<Custody>> Inode::resolve_as_link(Custody& base, RefPtr<Custody>* out_parent, int options, int symlink_recursion_level) const
91{
92 // The default implementation simply treats the stored
93 // contents as a path and resolves that. That is, it
94 // behaves exactly how you would expect a symlink to work.
95 auto contents = read_entire();
96
97 if (!contents) {
98 if (out_parent)
99 *out_parent = nullptr;
100 return KResult(-ENOENT);
101 }
102
103 auto path = StringView(contents.data(), contents.size());
104 return VFS::the().resolve_path(path, base, out_parent, options, symlink_recursion_level);
105}
106
107unsigned Inode::fsid() const
108{
109 return m_fs.fsid();
110}
111
112Inode::Inode(FS& fs, unsigned index)
113 : m_fs(fs)
114 , m_index(index)
115{
116 all_inodes().append(this);
117}
118
119Inode::~Inode()
120{
121 all_inodes().remove(this);
122}
123
124void Inode::will_be_destroyed()
125{
126 if (m_metadata_dirty)
127 flush_metadata();
128}
129
130void Inode::inode_contents_changed(off_t offset, ssize_t size, const u8* data)
131{
132 if (m_shared_vmobject)
133 m_shared_vmobject->inode_contents_changed({}, offset, size, data);
134}
135
136void Inode::inode_size_changed(size_t old_size, size_t new_size)
137{
138 if (m_shared_vmobject)
139 m_shared_vmobject->inode_size_changed({}, old_size, new_size);
140}
141
142int Inode::set_atime(time_t)
143{
144 return -ENOTIMPL;
145}
146
147int Inode::set_ctime(time_t)
148{
149 return -ENOTIMPL;
150}
151
152int Inode::set_mtime(time_t)
153{
154 return -ENOTIMPL;
155}
156
157KResult Inode::increment_link_count()
158{
159 return KResult(-ENOTIMPL);
160}
161
162KResult Inode::decrement_link_count()
163{
164 return KResult(-ENOTIMPL);
165}
166
167void Inode::set_shared_vmobject(SharedInodeVMObject& vmobject)
168{
169 m_shared_vmobject = vmobject.make_weak_ptr();
170}
171
172bool Inode::bind_socket(LocalSocket& socket)
173{
174 LOCKER(m_lock);
175 if (m_socket)
176 return false;
177 m_socket = socket;
178 return true;
179}
180
181bool Inode::unbind_socket()
182{
183 LOCKER(m_lock);
184 if (!m_socket)
185 return false;
186 m_socket = nullptr;
187 return true;
188}
189
190void Inode::register_watcher(Badge<InodeWatcher>, InodeWatcher& watcher)
191{
192 LOCKER(m_lock);
193 ASSERT(!m_watchers.contains(&watcher));
194 m_watchers.set(&watcher);
195}
196
197void Inode::unregister_watcher(Badge<InodeWatcher>, InodeWatcher& watcher)
198{
199 LOCKER(m_lock);
200 ASSERT(m_watchers.contains(&watcher));
201 m_watchers.remove(&watcher);
202}
203
204void Inode::set_metadata_dirty(bool metadata_dirty)
205{
206 if (m_metadata_dirty == metadata_dirty)
207 return;
208
209 m_metadata_dirty = metadata_dirty;
210 if (m_metadata_dirty) {
211 // FIXME: Maybe we should hook into modification events somewhere else, I'm not sure where.
212 // We don't always end up on this particular code path, for instance when writing to an ext2fs file.
213 LOCKER(m_lock);
214 for (auto& watcher : m_watchers) {
215 watcher->notify_inode_event({}, InodeWatcher::Event::Type::Modified);
216 }
217 }
218}
219
220KResult Inode::prepare_to_write_data()
221{
222 // FIXME: It's a poor design that filesystems are expected to call this before writing out data.
223 // We should funnel everything through an interface at the VFS layer so this can happen from a single place.
224 LOCKER(m_lock);
225 if (fs().is_readonly())
226 return KResult(-EROFS);
227 auto metadata = this->metadata();
228 if (metadata.is_setuid() || metadata.is_setgid()) {
229 dbg() << "Inode::prepare_to_write_data(): Stripping SUID/SGID bits from " << identifier();
230 return chmod(metadata.mode & ~(04000 | 02000));
231 }
232 return KSuccess;
233}
234
235}