xref: /DragonOS/kernel/src/filesystem/vfs/core.rs (revision 911132c4b8ea0e9c49a4e84b9fa1db114102acbb)
1 use core::{hint::spin_loop, sync::atomic::Ordering};
2 
3 use alloc::{string::ToString, sync::Arc};
4 use system_error::SystemError;
5 
6 use crate::{
7     driver::{base::block::disk_info::Partition, disk::ahci},
8     filesystem::{
9         devfs::devfs_init,
10         fat::fs::FATFileSystem,
11         procfs::procfs_init,
12         ramfs::RamFS,
13         sysfs::sysfs_init,
14         vfs::{mount::MountFS, syscall::ModeType, AtomicInodeId, FileSystem, FileType},
15     },
16     kdebug, kerror, kinfo,
17     process::ProcessManager,
18 };
19 
20 use super::{
21     file::FileMode,
22     utils::{rsplit_path, user_path_at},
23     IndexNode, InodeId, VFS_MAX_FOLLOW_SYMLINK_TIMES,
24 };
25 
26 /// @brief 原子地生成新的Inode号。
27 /// 请注意,所有的inode号都需要通过该函数来生成.全局的inode号,除了以下两个特殊的以外,都是唯一的
28 /// 特殊的两个inode号:
29 /// [0]: 对应'.'目录项
30 /// [1]: 对应'..'目录项
31 pub fn generate_inode_id() -> InodeId {
32     static INO: AtomicInodeId = AtomicInodeId::new(InodeId::new(1));
33     return INO.fetch_add(InodeId::new(1), Ordering::SeqCst);
34 }
35 
36 static mut __ROOT_INODE: Option<Arc<dyn IndexNode>> = None;
37 
38 /// @brief 获取全局的根节点
39 #[inline(always)]
40 #[allow(non_snake_case)]
41 pub fn ROOT_INODE() -> Arc<dyn IndexNode> {
42     unsafe {
43         return __ROOT_INODE.as_ref().unwrap().clone();
44     }
45 }
46 
47 /// 初始化虚拟文件系统
48 #[inline(never)]
49 pub fn vfs_init() -> Result<(), SystemError> {
50     // 使用Ramfs作为默认的根文件系统
51     let ramfs = RamFS::new();
52     let mount_fs = MountFS::new(ramfs, None);
53     let root_inode = mount_fs.root_inode();
54 
55     unsafe {
56         __ROOT_INODE = Some(root_inode.clone());
57     }
58 
59     // 创建文件夹
60     root_inode
61         .create("proc", FileType::Dir, ModeType::from_bits_truncate(0o755))
62         .expect("Failed to create /proc");
63     root_inode
64         .create("dev", FileType::Dir, ModeType::from_bits_truncate(0o755))
65         .expect("Failed to create /dev");
66     root_inode
67         .create("sys", FileType::Dir, ModeType::from_bits_truncate(0o755))
68         .expect("Failed to create /sys");
69     kdebug!("dir in root:{:?}", root_inode.list());
70 
71     procfs_init().expect("Failed to initialize procfs");
72 
73     devfs_init().expect("Failed to initialize devfs");
74 
75     sysfs_init().expect("Failed to initialize sysfs");
76 
77     let root_entries = ROOT_INODE().list().expect("VFS init failed");
78     if !root_entries.is_empty() {
79         kinfo!("Successfully initialized VFS!");
80     }
81     return Ok(());
82 }
83 
84 /// @brief 真正执行伪文件系统迁移的过程
85 ///
86 /// @param mountpoint_name 在根目录下的挂载点的名称
87 /// @param inode 原本的挂载点的inode
88 fn do_migrate(
89     new_root_inode: Arc<dyn IndexNode>,
90     mountpoint_name: &str,
91     fs: &MountFS,
92 ) -> Result<(), SystemError> {
93     let r = new_root_inode.find(mountpoint_name);
94     let mountpoint = if let Ok(r) = r {
95         r
96     } else {
97         new_root_inode
98             .create(
99                 mountpoint_name,
100                 FileType::Dir,
101                 ModeType::from_bits_truncate(0o755),
102             )
103             .unwrap_or_else(|_| panic!("Failed to create '/{mountpoint_name}' in migrating"))
104     };
105     // 迁移挂载点
106     mountpoint
107         .mount(fs.inner_filesystem())
108         .unwrap_or_else(|_| panic!("Failed to migrate {mountpoint_name} "));
109     return Ok(());
110 }
111 
112 /// @brief 迁移伪文件系统的inode
113 /// 请注意,为了避免删掉了伪文件系统内的信息,因此没有在原root inode那里调用unlink.
114 fn migrate_virtual_filesystem(new_fs: Arc<dyn FileSystem>) -> Result<(), SystemError> {
115     kinfo!("VFS: Migrating filesystems...");
116 
117     // ==== 在这里获取要被迁移的文件系统的inode ===
118     let binding = ROOT_INODE().find("proc").expect("ProcFS not mounted!").fs();
119     let proc: &MountFS = binding.as_any_ref().downcast_ref::<MountFS>().unwrap();
120     let binding = ROOT_INODE().find("dev").expect("DevFS not mounted!").fs();
121     let dev: &MountFS = binding.as_any_ref().downcast_ref::<MountFS>().unwrap();
122     let binding = ROOT_INODE().find("sys").expect("SysFs not mounted!").fs();
123     let sys: &MountFS = binding.as_any_ref().downcast_ref::<MountFS>().unwrap();
124 
125     let new_fs = MountFS::new(new_fs, None);
126     // 获取新的根文件系统的根节点的引用
127     let new_root_inode = new_fs.root_inode();
128 
129     // 把上述文件系统,迁移到新的文件系统下
130     do_migrate(new_root_inode.clone(), "proc", proc)?;
131     do_migrate(new_root_inode.clone(), "dev", dev)?;
132     do_migrate(new_root_inode.clone(), "sys", sys)?;
133     unsafe {
134         // drop旧的Root inode
135         let old_root_inode = __ROOT_INODE.take().unwrap();
136         drop(old_root_inode);
137 
138         // 设置全局的新的ROOT Inode
139         __ROOT_INODE = Some(new_root_inode);
140     }
141 
142     kinfo!("VFS: Migrate filesystems done!");
143 
144     return Ok(());
145 }
146 
147 pub fn mount_root_fs() -> Result<(), SystemError> {
148     kinfo!("Try to mount FAT32 as root fs...");
149     let partiton: Arc<Partition> = ahci::get_disks_by_name("ahci_disk_0".to_string())
150         .unwrap()
151         .0
152         .lock()
153         .partitions[0]
154         .clone();
155 
156     let fatfs: Result<Arc<FATFileSystem>, SystemError> = FATFileSystem::new(partiton);
157     if fatfs.is_err() {
158         kerror!(
159             "Failed to initialize fatfs, code={:?}",
160             fatfs.as_ref().err()
161         );
162         loop {
163             spin_loop();
164         }
165     }
166     let fatfs: Arc<FATFileSystem> = fatfs.unwrap();
167     let r = migrate_virtual_filesystem(fatfs);
168     if r.is_err() {
169         kerror!("Failed to migrate virtual filesystem to FAT32!");
170         loop {
171             spin_loop();
172         }
173     }
174     kinfo!("Successfully migrate rootfs to FAT32!");
175 
176     return Ok(());
177 }
178 
179 /// @brief 创建文件/文件夹
180 pub fn do_mkdir(path: &str, _mode: FileMode) -> Result<u64, SystemError> {
181     let path = path.trim();
182 
183     let inode: Result<Arc<dyn IndexNode>, SystemError> = ROOT_INODE().lookup(path);
184 
185     if let Err(errno) = inode {
186         // 文件不存在,且需要创建
187         if errno == SystemError::ENOENT {
188             let (filename, parent_path) = rsplit_path(path);
189             // 查找父目录
190             let parent_inode: Arc<dyn IndexNode> =
191                 ROOT_INODE().lookup(parent_path.unwrap_or("/"))?;
192             // 创建文件夹
193             let _create_inode: Arc<dyn IndexNode> = parent_inode.create(
194                 filename,
195                 FileType::Dir,
196                 ModeType::from_bits_truncate(0o755),
197             )?;
198         } else {
199             // 不需要创建文件,因此返回错误码
200             return Err(errno);
201         }
202     }
203 
204     return Ok(0);
205 }
206 
207 /// @brief 删除文件夹
208 pub fn do_remove_dir(dirfd: i32, path: &str) -> Result<u64, SystemError> {
209     let path = path.trim();
210 
211     let pcb = ProcessManager::current_pcb();
212     let (inode_begin, remain_path) = user_path_at(&pcb, dirfd, path)?;
213     let (filename, parent_path) = rsplit_path(&remain_path);
214 
215     // 最后一项文件项为.时返回EINVAL
216     if filename == "." {
217         return Err(SystemError::EINVAL);
218     }
219 
220     // 查找父目录
221     let parent_inode: Arc<dyn IndexNode> = inode_begin
222         .lookup_follow_symlink(parent_path.unwrap_or("/"), VFS_MAX_FOLLOW_SYMLINK_TIMES)?;
223 
224     if parent_inode.metadata()?.file_type != FileType::Dir {
225         return Err(SystemError::ENOTDIR);
226     }
227 
228     // 在目标点为symlink时也返回ENOTDIR
229     let target_inode = parent_inode.find(filename)?;
230     if target_inode.metadata()?.file_type != FileType::Dir {
231         return Err(SystemError::ENOTDIR);
232     }
233 
234     // 删除文件夹
235     parent_inode.rmdir(filename)?;
236 
237     return Ok(0);
238 }
239 
240 /// @brief 删除文件
241 pub fn do_unlink_at(dirfd: i32, path: &str) -> Result<u64, SystemError> {
242     let path = path.trim();
243 
244     let pcb = ProcessManager::current_pcb();
245     let (inode_begin, remain_path) = user_path_at(&pcb, dirfd, path)?;
246     let inode: Result<Arc<dyn IndexNode>, SystemError> =
247         inode_begin.lookup_follow_symlink(&remain_path, VFS_MAX_FOLLOW_SYMLINK_TIMES);
248 
249     if inode.is_err() {
250         let errno = inode.clone().unwrap_err();
251         // 文件不存在,且需要创建
252         if errno == SystemError::ENOENT {
253             return Err(SystemError::ENOENT);
254         }
255     }
256     // 禁止在目录上unlink
257     if inode.unwrap().metadata()?.file_type == FileType::Dir {
258         return Err(SystemError::EPERM);
259     }
260 
261     let (filename, parent_path) = rsplit_path(path);
262     // 查找父目录
263     let parent_inode: Arc<dyn IndexNode> = inode_begin
264         .lookup_follow_symlink(parent_path.unwrap_or("/"), VFS_MAX_FOLLOW_SYMLINK_TIMES)?;
265 
266     if parent_inode.metadata()?.file_type != FileType::Dir {
267         return Err(SystemError::ENOTDIR);
268     }
269 
270     // 删除文件
271     parent_inode.unlink(filename)?;
272 
273     return Ok(0);
274 }
275 
276 // @brief mount filesystem
277 pub fn do_mount(fs: Arc<dyn FileSystem>, mount_point: &str) -> Result<usize, SystemError> {
278     ROOT_INODE()
279         .lookup_follow_symlink(mount_point, VFS_MAX_FOLLOW_SYMLINK_TIMES)?
280         .mount(fs)?;
281     Ok(0)
282 }
283