introduce MountFS, mount RamFS at /tmp, mount DevFS at /dev

Author: wangrunji0408

kernel/Cargo.lock

@@ -65,9 +65,12 @@ smoltcp = { git = "https://github.com/rcore-os/smoltcp", default-features = fals
 bitmap-allocator = { git = "https://github.com/rcore-os/bitmap-allocator" }
 rcore-memory = { path = "../crate/memory" }
 rcore-thread = { git = "https://github.com/rcore-os/rcore-thread" }
-rcore-fs = { git = "https://github.com/rcore-os/rcore-fs" }
-rcore-fs-sfs = { git = "https://github.com/rcore-os/rcore-fs" }
-compression = { version="0.1.3", default-features = false, features=["gzip"]}
+rcore-fs = { git = "https://github.com/rcore-os/rcore-fs", rev = "22c759f4" }
+rcore-fs-sfs = { git = "https://github.com/rcore-os/rcore-fs", rev = "22c759f4" }
+rcore-fs-ramfs = { git = "https://github.com/rcore-os/rcore-fs", rev = "22c759f4" }
+rcore-fs-mountfs = { git = "https://github.com/rcore-os/rcore-fs", rev = "22c759f4" }
+rcore-fs-devfs = { git = "https://github.com/rcore-os/rcore-fs", rev = "22c759f4" }
+compression = { version = "0.1.3", default-features = false, features = ["gzip"] }
 
 
 [target.'cfg(target_arch = "x86_64")'.dependencies]

kernel/Cargo.toml

@@ -3,6 +3,9 @@ use alloc::{sync::Arc, vec::Vec};
 use rcore_fs::dev::block_cache::BlockCache;
 use rcore_fs::vfs::*;
 use rcore_fs_sfs::SimpleFileSystem;
+use rcore_fs_mountfs::MountFS;
+use rcore_fs_ramfs::RamFS;
+use rcore_fs_devfs::{DevFS, special::*};
 
 use crate::drivers::BlockDriver;
 
@@ -69,8 +72,26 @@ lazy_static! {
             Arc::new(unsafe { device::MemBuf::new(_user_img_start, _user_img_end) })
         };
 
+        // use SFS as rootfs
         let sfs = SimpleFileSystem::open(device).expect("failed to open SFS");
-        sfs.root_inode()
+        let rootfs = MountFS::new(sfs);
+        let root = rootfs.root_inode();
+
+        // create DevFS
+        let devfs = DevFS::new();
+        devfs.add("null", Arc::new(NullINode::default())).expect("failed to mknod /dev/null");
+        devfs.add("zero", Arc::new(ZeroINode::default())).expect("failed to mknod /dev/zero");
+
+        // mount DevFS at /dev
+        let dev = root.create("dev", FileType::Dir, 0o666).expect("failed to mkdir /dev");
+        dev.mount(devfs).expect("failed to mount DevFS");
+
+        // mount RamFS at /tmp
+        let ramfs = RamFS::new();
+        let tmp = root.create("tmp", FileType::Dir, 0o666).expect("failed to mkdir /tmp");
+        tmp.mount(ramfs).expect("failed to mount RamFS");
+
+        root
     };
 }
 

kernel/src/fs/mod.rs

@@ -951,6 +951,8 @@ impl From<FsError> for SysError {
             FsError::IOCTLError => SysError::EINVAL,
             FsError::NoDevice => SysError::EINVAL,
             FsError::Again => SysError::EAGAIN,
+            FsError::SymLoop => SysError::ELOOP,
+            FsError::Busy => SysError::EBUSY,
         }
     }
 }

kernel/src/syscall/fs.rs

@@ -486,6 +486,7 @@ pub enum SysError {
     ENOLCK = 37,
     ENOSYS = 38,
     ENOTEMPTY = 39,
+    ELOOP = 40,
     ENOTSOCK = 80,
     ENOPROTOOPT = 92,
     EPFNOSUPPORT = 96,
@@ -543,6 +544,7 @@ impl fmt::Display for SysError {
                 ENOLCK => "No record locks available",
                 ENOSYS => "Function not implemented",
                 ENOTEMPTY => "Directory not empty",
+                ELOOP => "Too many symbolic links encountered",
                 ENOTSOCK => "Socket operation on non-socket",
                 ENOPROTOOPT => "Protocol not available",
                 EPFNOSUPPORT => "Protocol family not supported",