Improve absolute path and symlink resolution

rcore-fs-sfs/src/lib.rs

@@ -308,7 +308,7 @@ impl vfs::INode for INodeImpl {
         })
     }
 
-    fn chmod(&self, mode: u16) -> vfs::Result<()> {
+    fn chmod(&self, _mode: u16) -> vfs::Result<()> {
         // No-op for sfs
         Ok(())
     }

rcore-fs-sfs/src/tests.rs

@@ -119,9 +119,57 @@ fn create_then_lookup() -> Result<()> {
         .expect("failed to create dir1");
     let file2 = dir1.create("file2", FileType::File, 0o777)
         .expect("failed to create /dir1/file2");
-    assert!(Arc::ptr_eq(&root.lookup("dir1/file2")?, &file2), "failed to find dir1/file1");
+    assert!(Arc::ptr_eq(&root.lookup("dir1/file2")?, &file2), "failed to find dir1/file2");
     assert!(Arc::ptr_eq(&dir1.lookup("..")?, &root), "failed to find .. from dir1");
 
+    assert!(Arc::ptr_eq(&dir1.lookup("../dir1/file2")?, &file2), "failed to find dir1/file2 by relative");
+    assert!(Arc::ptr_eq(&dir1.lookup("/dir1/file2")?, &file2), "failed to find dir1/file2 by absolute");
+    assert!(Arc::ptr_eq(&dir1.lookup("/dir1/../dir1/file2")?, &file2), "failed to find dir1/file2 by absolute");
+    assert!(Arc::ptr_eq(&dir1.lookup("../../..//dir1/../dir1/file2")?, &file2), "failed to find dir1/file2 by more than one ..");
+    assert!(Arc::ptr_eq(&dir1.lookup("..//dir1/file2")?, &file2), "failed to find dir1/file2 by weird relative");
+
+    sfs.sync()?;
+    Ok(())
+}
+
+#[test]
+fn test_symlinks() -> Result<()> {
+    let sfs = _create_new_sfs();
+    let root = sfs.root_inode();
+
+    let file1 = root.create("file1", FileType::File, 0o777)
+        .expect("failed to create file1");
+    assert!(Arc::ptr_eq(&root.lookup("file1")?, &file1), "failed to find file1");
+
+    let link1 = root.create("link1", FileType::SymLink, 0o777)
+        .expect("failed to create link1");
+    let data = "file1".as_bytes();
+    link1.resize(data.len())?;
+    link1.write_at(0, data)?;
+
+    let link2 = root.create("link2", FileType::SymLink, 0o777)
+        .expect("failed to create link2");
+    let data = "link1".as_bytes();
+    link2.resize(data.len())?;
+    link2.write_at(0, data)?;
+
+    assert!(Arc::ptr_eq(&root.lookup("link1")?, &link1), "failed to find link1 by relative");
+    assert!(Arc::ptr_eq(&root.lookup_follow("link1", 1)?, &file1), "failed to find file1 by link1");
+    assert!(Arc::ptr_eq(&root.lookup_follow("link2", 0)?, &link2), "failed to find link2 by link2");
+    assert!(Arc::ptr_eq(&root.lookup_follow("link2", 1)?, &link1), "failed to find link1 by link2");
+    assert!(Arc::ptr_eq(&root.lookup_follow("link2", 2)?, &file1), "failed to find file1 by link2");
+
+    let link3 = root.create("link3", FileType::SymLink, 0o777)
+        .expect("failed to create link3");
+    let data = "/link2".as_bytes();
+    link3.resize(data.len())?;
+    link3.write_at(0, data)?;
+
+    assert!(Arc::ptr_eq(&root.lookup_follow("link3", 0)?, &link3), "failed to find link3 by link3");
+    assert!(Arc::ptr_eq(&root.lookup_follow("link3", 1)?, &link2), "failed to find link2 by link3");
+    assert!(Arc::ptr_eq(&root.lookup_follow("link3", 2)?, &link1), "failed to find link1 by link3");
+    assert!(Arc::ptr_eq(&root.lookup_follow("link3", 3)?, &file1), "failed to find file1 by link2");
+
     sfs.sync()?;
     Ok(())
 }

rcore-fs/src/vfs.rs

@@ -58,12 +58,17 @@ impl INode {
         if self.metadata()?.type_ != FileType::Dir {
             return Err(FsError::NotDir);
         }
+
         let mut result = self.find(".")?;
         let mut rest_path = String::from(path);
         while rest_path != "" {
-            if result.metadata()?.type_!= FileType::Dir {
+            if result.metadata()?.type_ != FileType::Dir {
                 return Err(FsError::NotDir);
             }
+            // handle absolute path
+            if let Some('/') = rest_path.chars().next() {
+                return self.fs().root_inode().lookup_follow(&path[1..], follow_times);
+            }
             let name;
             match rest_path.find('/') {
                 None => {
@@ -86,8 +91,7 @@ impl INode {
                         if let Ok(path) = str::from_utf8(&content[..len]) {
                             if let Some('/') = path.chars().next() {
                                 // absolute link
-                                result = result.fs().root_inode();
-                                rest_path = String::from(&path[1..]);
+                                return result.fs().root_inode().lookup_follow(&path[1..], follow_times);
                             } else {
                                 // relative link
                                 // result remains unchanged