xref: /DragonOS/kernel/src/filesystem/devfs/mod.rs (revision 33270d005c230d4bcd9cca0704bcd92b2a4faa90) 
1 /// 导出devfs的模块
2 pub mod null_dev;
3 pub mod zero_dev;
4 
5 use super::vfs::{
6     core::{generate_inode_id, ROOT_INODE},
7     FileSystem, FileType, FsInfo, IndexNode, Metadata, PollStatus,
8 };
9 use crate::{
10     include::bindings::bindings::{EEXIST, EISDIR, ENOENT, ENOTDIR, ENOTSUP},
11     kdebug, kerror,
12     libs::spinlock::{SpinLock, SpinLockGuard},
13     time::TimeSpec,
14 };
15 use alloc::{
16     collections::BTreeMap,
17     string::{String, ToString},
18     sync::{Arc, Weak},
19     vec::Vec,
20 };
21 
22 const DEVFS_MAX_NAMELEN: usize = 64;
23 
24 /// @brief dev文件系统
25 #[derive(Debug)]
26 pub struct DevFS {
27     // 文件系统根节点
28     root_inode: Arc<LockedDevFSInode>,
29 }
30 
31 impl FileSystem for DevFS {
32     fn as_any_ref(&self) -> &dyn core::any::Any {
33         self
34     }
35 
36     fn root_inode(&self) -> Arc<dyn super::vfs::IndexNode> {
37         return self.root_inode.clone();
38     }
39 
40     fn info(&self) -> super::vfs::FsInfo {
41         return FsInfo {
42             blk_dev_id: 0,
43             max_name_len: DEVFS_MAX_NAMELEN,
44         };
45     }
46 }
47 
48 impl DevFS {
49     pub fn new() -> Arc<Self> {
50         // 初始化root inode
51         let root: Arc<LockedDevFSInode> = Arc::new(LockedDevFSInode(SpinLock::new(
52             // /dev 的权限设置为 读+执行，root 可以读写
53             // root 的 parent 是空指针
54             DevFSInode::new(FileType::Dir, 0o755 as u32, 0),
55         )));
56 
57         let devfs: Arc<DevFS> = Arc::new(DevFS { root_inode: root });
58 
59         // 对root inode加锁，并继续完成初始化工作
60         let mut root_guard: SpinLockGuard<DevFSInode> = devfs.root_inode.0.lock();
61         root_guard.parent = Arc::downgrade(&devfs.root_inode);
62         root_guard.self_ref = Arc::downgrade(&devfs.root_inode);
63         root_guard.fs = Arc::downgrade(&devfs);
64         // 释放锁
65         drop(root_guard);
66 
67         // 创建文件夹
68         let root: &Arc<LockedDevFSInode> = &devfs.root_inode;
69         root.add_dir("char")
70             .expect("DevFS: Failed to create /dev/char");
71 
72         root.add_dir("block")
73             .expect("DevFS: Failed to create /dev/block");
74         devfs.register_bultinin_device();
75 
76         // kdebug!("ls /dev: {:?}", root.list());
77         return devfs;
78     }
79 
80     /// @brief 注册系统内部自带的设备
81     fn register_bultinin_device(&self) {
82         use null_dev::LockedNullInode;
83         use zero_dev::LockedZeroInode;
84         let dev_root: Arc<LockedDevFSInode> = self.root_inode.clone();
85         dev_root
86             .add_dev("null", LockedNullInode::new())
87             .expect("DevFS: Failed to register /dev/null");
88         dev_root
89             .add_dev("zero", LockedZeroInode::new())
90             .expect("DevFS: Failed to register /dev/zero");
91     }
92 
93     /// @brief 在devfs内注册设备
94     ///
95     /// @param name 设备名称
96     /// @param device 设备节点的结构体
97     pub fn register_device<T: DeviceINode>(&self, name: &str, device: Arc<T>) -> Result<(), i32> {
98         let dev_root_inode: Arc<LockedDevFSInode> = self.root_inode.clone();
99         match device.metadata().unwrap().file_type {
100             // 字节设备挂载在 /dev/char
101             FileType::CharDevice => {
102                 if let Err(_) = dev_root_inode.find("char") {
103                     dev_root_inode.create("char", FileType::Dir, 0o755)?;
104                 }
105 
106                 let any_char_inode = dev_root_inode.find("char")?;
107                 let dev_char_inode: &LockedDevFSInode = any_char_inode
108                     .as_any_ref()
109                     .downcast_ref::<LockedDevFSInode>()
110                     .unwrap();
111 
112                 dev_char_inode.add_dev(name, device.clone())?;
113                 device.set_fs(dev_char_inode.0.lock().fs.clone());
114             }
115             FileType::BlockDevice => {
116                 if let Err(_) = dev_root_inode.find("block") {
117                     dev_root_inode.create("block", FileType::Dir, 0o755)?;
118                 }
119 
120                 let any_block_inode = dev_root_inode.find("block")?;
121                 let dev_block_inode: &LockedDevFSInode = any_block_inode
122                     .as_any_ref()
123                     .downcast_ref::<LockedDevFSInode>()
124                     .unwrap();
125 
126                 dev_block_inode.add_dev(name, device.clone())?;
127                 device.set_fs(dev_block_inode.0.lock().fs.clone());
128             }
129             _ => {
130                 return Err(-(ENOTSUP as i32));
131             }
132         }
133 
134         return Ok(());
135     }
136 
137     /// @brief 卸载设备
138     pub fn unregister_device<T: DeviceINode>(&self, name: &str, device: Arc<T>) -> Result<(), i32> {
139         let dev_root_inode: Arc<LockedDevFSInode> = self.root_inode.clone();
140         match device.metadata().unwrap().file_type {
141             // 字节设备挂载在 /dev/char
142             FileType::CharDevice => {
143                 if let Err(_) = dev_root_inode.find("char") {
144                     return Err(-(ENOENT as i32));
145                 }
146 
147                 let any_char_inode = dev_root_inode.find("char")?;
148                 let dev_char_inode = any_char_inode
149                     .as_any_ref()
150                     .downcast_ref::<LockedDevFSInode>()
151                     .unwrap();
152                 // TODO： 调用设备的卸载接口（当引入卸载接口之后）
153                 dev_char_inode.remove(name)?;
154             }
155             FileType::BlockDevice => {
156                 if let Err(_) = dev_root_inode.find("block") {
157                     return Err(-(ENOENT as i32));
158                 }
159 
160                 let any_block_inode = dev_root_inode.find("block")?;
161                 let dev_block_inode = any_block_inode
162                     .as_any_ref()
163                     .downcast_ref::<LockedDevFSInode>()
164                     .unwrap();
165 
166                 dev_block_inode.remove(name)?;
167             }
168             _ => {
169                 return Err(-(ENOTSUP as i32));
170             }
171         }
172 
173         return Ok(());
174     }
175 }
176 
177 /// @brief dev文件i节点(锁)
178 #[derive(Debug)]
179 pub struct LockedDevFSInode(SpinLock<DevFSInode>);
180 
181 /// @brief dev文件i节点(无锁)
182 #[derive(Debug)]
183 pub struct DevFSInode {
184     /// 指向父Inode的弱引用
185     parent: Weak<LockedDevFSInode>,
186     /// 指向自身的弱引用
187     self_ref: Weak<LockedDevFSInode>,
188     /// 子Inode的B树
189     children: BTreeMap<String, Arc<dyn IndexNode>>,
190     /// 指向inode所在的文件系统对象的指针
191     fs: Weak<DevFS>,
192     /// INode 元数据
193     metadata: Metadata,
194 }
195 
196 impl DevFSInode {
197     pub fn new(dev_type_: FileType, mode_: u32, data_: usize) -> Self {
198         return Self::new_with_parent(Weak::default(), dev_type_, mode_, data_);
199     }
200 
201     pub fn new_with_parent(
202         parent: Weak<LockedDevFSInode>,
203         dev_type_: FileType,
204         mode_: u32,
205         data_: usize,
206     ) -> Self {
207         return DevFSInode {
208             parent: parent,
209             self_ref: Weak::default(),
210             children: BTreeMap::new(),
211             metadata: Metadata {
212                 dev_id: 1,
213                 inode_id: generate_inode_id(),
214                 size: 0,
215                 blk_size: 0,
216                 blocks: 0,
217                 atime: TimeSpec::default(),
218                 mtime: TimeSpec::default(),
219                 ctime: TimeSpec::default(),
220                 file_type: dev_type_, // 文件夹
221                 mode: mode_,
222                 nlinks: 1,
223                 uid: 0,
224                 gid: 0,
225                 raw_dev: data_,
226             },
227             fs: Weak::default(),
228         };
229     }
230 }
231 
232 impl LockedDevFSInode {
233     pub fn add_dir(&self, name: &str) -> Result<(), i32> {
234         let guard:SpinLockGuard<DevFSInode> = self.0.lock();
235 
236         if guard.children.contains_key(name) {
237             return Err(-(EEXIST as i32));
238         }
239 
240         match self.do_create_with_data(guard, name, FileType::Dir, 0o755 as u32, 0) {
241             Ok(inode) => inode,
242             Err(err) => {
243                 return Err(err);
244             }
245         };
246 
247         return Ok(());
248     }
249 
250     pub fn add_dev(&self, name: &str, dev: Arc<dyn IndexNode>) -> Result<(), i32> {
251         let mut this = self.0.lock();
252 
253         if this.children.contains_key(name) {
254             return Err(-(EEXIST as i32));
255         }
256 
257         this.children.insert(name.to_string(), dev);
258         return Ok(());
259     }
260 
261     pub fn remove(&self, name: &str) -> Result<(), i32> {
262         let x = self
263             .0
264             .lock()
265             .children
266             .remove(name)
267             .ok_or(-(ENOENT as i32))?;
268 
269         drop(x);
270         return Ok(());
271     }
272 
273     fn do_create_with_data(&self, mut guard: SpinLockGuard<DevFSInode>,_name: &str,
274         _file_type: FileType,
275         _mode: u32,
276         _data: usize,) -> Result<Arc<dyn IndexNode>, i32>{
277         if guard.metadata.file_type != FileType::Dir {
278             return Err(-(ENOTDIR as i32));
279         }
280 
281         // 如果有重名的，则返回
282         if guard.children.contains_key(_name) {
283             return Err(-(EEXIST as i32));
284         }
285 
286         // 创建inode
287         let result: Arc<LockedDevFSInode> = Arc::new(LockedDevFSInode(SpinLock::new(DevFSInode {
288             parent: guard.self_ref.clone(),
289             self_ref: Weak::default(),
290             children: BTreeMap::new(),
291             metadata: Metadata {
292                 dev_id: 0,
293                 inode_id: generate_inode_id(),
294                 size: 0,
295                 blk_size: 0,
296                 blocks: 0,
297                 atime: TimeSpec::default(),
298                 mtime: TimeSpec::default(),
299                 ctime: TimeSpec::default(),
300                 file_type: _file_type,
301                 mode: _mode,
302                 nlinks: 1,
303                 uid: 0,
304                 gid: 0,
305                 raw_dev: _data,
306             },
307             fs: guard.fs.clone(),
308         })));
309 
310         // 初始化inode的自引用的weak指针
311         result.0.lock().self_ref = Arc::downgrade(&result);
312 
313         // 将子inode插入父inode的B树中
314         guard.children.insert(String::from(_name), result.clone());
315         return Ok(result);
316 
317     }
318 }
319 
320 impl IndexNode for LockedDevFSInode {
321     fn as_any_ref(&self) -> &dyn core::any::Any {
322         self
323     }
324 
325     fn open(&self, _data: &mut super::vfs::FilePrivateData) -> Result<(), i32> {
326         return Ok(());
327     }
328 
329     fn close(&self, _data: &mut super::vfs::FilePrivateData) -> Result<(), i32> {
330         return Ok(());
331     }
332 
333     fn create_with_data(
334         &self,
335         name: &str,
336         file_type: FileType,
337         mode: u32,
338         data: usize,
339     ) -> Result<Arc<dyn IndexNode>, i32> {
340         // 获取当前inode
341         let guard:SpinLockGuard<DevFSInode> = self.0.lock();
342         // 如果当前inode不是文件夹，则返回
343         return self.do_create_with_data(guard, name, file_type, mode, data);
344     }
345 
346     fn find(&self, name: &str) -> Result<Arc<dyn IndexNode>, i32> {
347         let inode = self.0.lock();
348 
349         if inode.metadata.file_type != FileType::Dir {
350             return Err(-(ENOTDIR as i32));
351         }
352 
353         match name {
354             "" | "." => {
355                 return Ok(inode.self_ref.upgrade().ok_or(-(ENOENT as i32))?);
356             }
357             ".." => {
358                 return Ok(inode.parent.upgrade().ok_or(-(ENOENT as i32))?);
359             }
360             name => {
361                 // 在子目录项中查找
362                 return Ok(inode.children.get(name).ok_or(-(ENOENT as i32))?.clone());
363             }
364         }
365     }
366 
367     fn fs(&self) -> Arc<dyn FileSystem> {
368         return self.0.lock().fs.upgrade().unwrap();
369     }
370 
371     fn get_entry_name(&self, ino: super::vfs::InodeId) -> Result<String, i32> {
372         let inode: SpinLockGuard<DevFSInode> = self.0.lock();
373         if inode.metadata.file_type != FileType::Dir {
374             return Err(-(ENOTDIR as i32));
375         }
376 
377         match ino {
378             0 => {
379                 return Ok(String::from("."));
380             }
381             1 => {
382                 return Ok(String::from(".."));
383             }
384             ino => {
385                 // 暴力遍历所有的children，判断inode id是否相同
386                 // TODO: 优化这里，这个地方性能很差！
387                 let mut key: Vec<String> = inode
388                     .children
389                     .keys()
390                     .filter(|k| inode.children.get(*k).unwrap().metadata().unwrap().inode_id == ino)
391                     .cloned()
392                     .collect();
393 
394                 match key.len() {
395                     0=>{return Err(-(ENOENT as i32));}
396                     1=>{return Ok(key.remove(0));}
397                     _ => panic!("Devfs get_entry_name: key.len()={key_len}>1, current inode_id={inode_id}, to find={to_find}", key_len=key.len(), inode_id = inode.metadata.inode_id, to_find=ino)
398                 }
399             }
400         }
401     }
402 
403     fn ioctl(&self, _cmd: u32, _data: usize) -> Result<usize, i32> {
404         Err(-(ENOTSUP as i32))
405     }
406 
407     fn list(&self) -> Result<Vec<String>, i32> {
408         let info = self.metadata()?;
409         if info.file_type != FileType::Dir {
410             return Err(-(ENOTDIR as i32));
411         }
412 
413         let mut keys: Vec<String> = Vec::new();
414         keys.push(String::from("."));
415         keys.push(String::from(".."));
416         keys.append(&mut self.0.lock().children.keys().cloned().collect());
417 
418         return Ok(keys);
419     }
420 
421     fn metadata(&self) -> Result<Metadata, i32> {
422         return Ok(self.0.lock().metadata.clone());
423     }
424 
425     fn set_metadata(&self, metadata: &Metadata) -> Result<(), i32> {
426         let mut inode = self.0.lock();
427         inode.metadata.atime = metadata.atime;
428         inode.metadata.mtime = metadata.mtime;
429         inode.metadata.ctime = metadata.ctime;
430         inode.metadata.mode = metadata.mode;
431         inode.metadata.uid = metadata.uid;
432         inode.metadata.gid = metadata.gid;
433 
434         return Ok(());
435     }
436 
437     fn poll(&self) -> Result<super::vfs::PollStatus, i32> {
438         // 加锁
439         let inode: SpinLockGuard<DevFSInode> = self.0.lock();
440 
441         // 检查当前inode是否为一个文件夹，如果是的话，就返回错误
442         if inode.metadata.file_type == FileType::Dir {
443             return Err(-(EISDIR as i32));
444         }
445 
446         return Ok(PollStatus {
447             flags: PollStatus::READ_MASK | PollStatus::WRITE_MASK,
448         });
449     }
450 
451     /// 读设备 - 应该调用设备的函数读写，而不是通过文件系统读写
452     fn read_at(
453         &self,
454         _offset: usize,
455         _len: usize,
456         _buf: &mut [u8],
457         _data: &mut super::vfs::file::FilePrivateData,
458     ) -> Result<usize, i32> {
459         Err(-(ENOTSUP as i32))
460     }
461 
462     /// 写设备 - 应该调用设备的函数读写，而不是通过文件系统读写
463     fn write_at(
464         &self,
465         _offset: usize,
466         _len: usize,
467         _buf: &[u8],
468         _data: &mut super::vfs::file::FilePrivateData,
469     ) -> Result<usize, i32> {
470         Err(-(ENOTSUP as i32))
471     }
472 }
473 
474 /// @brief 所有的设备INode都需要额外实现这个trait
475 pub trait DeviceINode: IndexNode {
476     fn set_fs(&self, fs: Weak<DevFS>);
477     // TODO: 增加 unregister 方法
478 }
479 
480 /// @brief 获取devfs实例的强类型不可变引用
481 macro_rules! devfs_exact_ref {
482     () => {{
483         let devfs_inode: Result<Arc<dyn IndexNode>, i32> = ROOT_INODE().find("dev");
484         if let Err(e) = devfs_inode {
485             kerror!("failed to get DevFS ref. errcode = {e}");
486             return Err(-(ENOENT as i32));
487         }
488 
489         let binding = devfs_inode.unwrap();
490         let devfs_inode: &LockedDevFSInode = binding
491             .as_any_ref()
492             .downcast_ref::<LockedDevFSInode>()
493             .unwrap();
494         let binding = devfs_inode.fs();
495         binding
496     }
497     .as_any_ref()
498     .downcast_ref::<DevFS>()
499     .unwrap()};
500 }
501 /// @brief devfs的设备注册函数
502 pub fn devfs_register<T: DeviceINode>(name: &str, device: Arc<T>) -> Result<(), i32> {
503     return devfs_exact_ref!().register_device(name, device);
504 }
505 
506 /// @brief devfs的设备卸载函数
507 #[allow(dead_code)]
508 pub fn devfs_unregister<T: DeviceINode>(name: &str, device: Arc<T>) -> Result<(), i32> {
509     return devfs_exact_ref!().unregister_device(name, device);
510 }
511