starnix_core/fs/
debugfs.rs

1// Copyright 2025 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5use crate::task::{CurrentTask, Kernel};
6use crate::vfs::pseudo::simple_directory::{SimpleDirectory, SimpleDirectoryMutator};
7use crate::vfs::pseudo::stub_empty_file::StubEmptyFile;
8use crate::vfs::{
9    CacheMode, FileSystem, FileSystemHandle, FileSystemOps, FileSystemOptions, FsStr,
10};
11use starnix_logging::bug_ref;
12use starnix_types::vfs::default_statfs;
13use starnix_uapi::errors::Errno;
14use starnix_uapi::file_mode::mode;
15use starnix_uapi::{DEBUGFS_MAGIC, statfs};
16
17struct DebugFs;
18
19impl FileSystemOps for DebugFs {
20    fn statfs(&self, _fs: &FileSystem, _current_task: &CurrentTask) -> Result<statfs, Errno> {
21        Ok(default_statfs(DEBUGFS_MAGIC))
22    }
23    fn name(&self) -> &'static FsStr {
24        "debugfs".into()
25    }
26}
27
28impl DebugFs {
29    fn new_fs(kernel: &Kernel, options: FileSystemOptions) -> FileSystemHandle {
30        let fs =
31            FileSystem::new(kernel, CacheMode::Cached(kernel.fs_cache_config()), DebugFs, options)
32                .expect("debugfs constructed with valid options");
33
34        let root = SimpleDirectory::new();
35        fs.create_root(fs.allocate_ino(), root.clone());
36
37        let dir = SimpleDirectoryMutator::new(fs.clone(), root);
38        let dir_mode = 0o700;
39        dir.subdir("binder", dir_mode, |dir| {
40            dir.entry(
41                "failed_transaction_log",
42                StubEmptyFile::new_node(bug_ref!("https://fxbug.dev/452096300")),
43                mode!(IFREG, 0o444),
44            );
45            dir.entry(
46                "state",
47                StubEmptyFile::new_node(bug_ref!("https://fxbug.dev/452096300")),
48                mode!(IFREG, 0o444),
49            );
50            dir.entry(
51                "stats",
52                StubEmptyFile::new_node(bug_ref!("https://fxbug.dev/452096300")),
53                mode!(IFREG, 0o444),
54            );
55            dir.entry(
56                "transaction_log",
57                StubEmptyFile::new_node(bug_ref!("https://fxbug.dev/452096300")),
58                mode!(IFREG, 0o444),
59            );
60            dir.entry(
61                "transactions",
62                StubEmptyFile::new_node(bug_ref!("https://fxbug.dev/452096300")),
63                mode!(IFREG, 0o444),
64            );
65        });
66        dir.subdir("mmc0", dir_mode, |dir| {
67            dir.subdir("mmc0:0001", dir_mode, |dir| {
68                dir.entry(
69                    "ext_csd",
70                    StubEmptyFile::new_node(bug_ref!("https://fxbug.dev/452096300")),
71                    mode!(IFREG, 0o444),
72                );
73            });
74        });
75        dir.subdir("tracing", 0o644, |_| ());
76
77        fs
78    }
79}
80
81struct DebugFsHandle(FileSystemHandle);
82
83pub fn debug_fs(
84    current_task: &CurrentTask,
85    _options: FileSystemOptions,
86) -> Result<FileSystemHandle, Errno> {
87    Ok(get_debugfs(current_task.kernel()))
88}
89
90pub fn get_debugfs(kernel: &Kernel) -> FileSystemHandle {
91    kernel
92        .expando
93        .get_or_init(|| DebugFsHandle(DebugFs::new_fs(kernel, FileSystemOptions::default())))
94        .0
95        .clone()
96}
starnix_core/fs/debugfs.rs

starnix_core/fs/
debugfs.rs
