starnix_modules_debugfs/
lib.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
5#![recursion_limit = "512"]
6
7use starnix_core::task::{CurrentTask, Kernel};
8use starnix_core::vfs::pseudo::simple_directory::{SimpleDirectory, SimpleDirectoryMutator};
9use starnix_core::vfs::pseudo::stub_empty_file::StubEmptyFile;
10use starnix_core::vfs::{
11    CacheMode, FileSystem, FileSystemHandle, FileSystemOps, FileSystemOptions, FsStr,
12};
13use starnix_logging::bug_ref;
14use starnix_types::vfs::default_statfs;
15use starnix_uapi::errors::Errno;
16use starnix_uapi::file_mode::mode;
17use starnix_uapi::{DEBUGFS_MAGIC, statfs};
18
19struct DebugFs;
20
21impl FileSystemOps for DebugFs {
22    fn statfs(&self, _fs: &FileSystem, _current_task: &CurrentTask) -> Result<statfs, Errno> {
23        Ok(default_statfs(DEBUGFS_MAGIC))
24    }
25    fn name(&self) -> &'static FsStr {
26        "debugfs".into()
27    }
28}
29
30impl DebugFs {
31    fn new_fs(kernel: &Kernel, options: FileSystemOptions) -> FileSystemHandle {
32        let fs =
33            FileSystem::new(kernel, CacheMode::Cached(kernel.fs_cache_config()), DebugFs, options)
34                .expect("debugfs constructed with valid options");
35
36        let root = SimpleDirectory::new();
37        fs.create_root(fs.allocate_ino(), root.clone());
38
39        let dir = SimpleDirectoryMutator::new(fs.clone(), root);
40        let dir_mode = 0o700;
41        dir.subdir("binder", dir_mode, |dir| {
42            dir.entry(
43                "failed_transaction_log",
44                StubEmptyFile::new_node(bug_ref!("https://fxbug.dev/452096300")),
45                mode!(IFREG, 0o444),
46            );
47            dir.entry(
48                "state",
49                StubEmptyFile::new_node(bug_ref!("https://fxbug.dev/452096300")),
50                mode!(IFREG, 0o444),
51            );
52            dir.entry(
53                "stats",
54                StubEmptyFile::new_node(bug_ref!("https://fxbug.dev/452096300")),
55                mode!(IFREG, 0o444),
56            );
57            dir.entry(
58                "transaction_log",
59                StubEmptyFile::new_node(bug_ref!("https://fxbug.dev/452096300")),
60                mode!(IFREG, 0o444),
61            );
62            dir.entry(
63                "transactions",
64                StubEmptyFile::new_node(bug_ref!("https://fxbug.dev/452096300")),
65                mode!(IFREG, 0o444),
66            );
67        });
68        dir.subdir("mmc0", dir_mode, |dir| {
69            dir.subdir("mmc0:0001", dir_mode, |dir| {
70                dir.entry(
71                    "ext_csd",
72                    StubEmptyFile::new_node(bug_ref!("https://fxbug.dev/452096300")),
73                    mode!(IFREG, 0o444),
74                );
75            });
76        });
77        dir.subdir("tracing", 0o644, |_| ());
78
79        fs
80    }
81}
82
83struct DebugFsHandle(FileSystemHandle);
84
85pub fn debug_fs(
86    current_task: &CurrentTask,
87    _options: FileSystemOptions,
88) -> Result<FileSystemHandle, Errno> {
89    Ok(get_debugfs(current_task.kernel()))
90}
91
92pub fn get_debugfs(kernel: &Kernel) -> FileSystemHandle {
93    kernel
94        .expando
95        .get_or_init(|| DebugFsHandle(DebugFs::new_fs(kernel, FileSystemOptions::default())))
96        .0
97        .clone()
98}
starnix_modules_debugfs/lib.rs

starnix_modules_debugfs/
lib.rs
