Fix SFTP path resolution and EOF handling

- Fix resolve_path() to handle non-existent files (for upload)
- Add SSH_MSG_CHANNEL_EOF handling in service loop
- Canonicalize root_dir in SftpHandler constructor
- SFTP now fully working: pwd, ls, cd, get, put operations verified

markbase-core/src/ssh_server/server.rs

@@ -345,6 +345,10 @@ fn handle_ssh_service_loop(
                 }
                 break;
             }
+            Some(&pt) if pt == PacketType::SSH_MSG_CHANNEL_EOF as u8 => {
+                info!("Received SSH_MSG_CHANNEL_EOF");
+                // EOF means client won't send more data, just acknowledge and continue
+            }
             Some(&pt) if pt == PacketType::SSH_MSG_DISCONNECT as u8 => {
                 info!("Received SSH_MSG_DISCONNECT");
                 break;

markbase-core/src/ssh_server/sftp_handler.rs

@@ -236,8 +236,9 @@ pub struct SftpHandler {
 
 impl SftpHandler {
     pub fn new(root_dir: PathBuf) -> Self {
+        let canonical_root = root_dir.canonicalize().unwrap_or(root_dir);
         Self {
-            root_dir,
+            root_dir: canonical_root,
             next_handle_id: 0,
             handles: std::collections::HashMap::new(),
         }
@@ -728,20 +729,36 @@ impl SftpHandler {
 
     /// 解析路径（安全性检查，参考OpenSSH sftp-server.c: path_resolve())
     fn resolve_path(&self, path: &str) -> Result<PathBuf> {
-        let full_path = if path.starts_with('/') {
+        info!("resolve_path: input={}, root_dir={:?}", path, self.root_dir);
-            self.root_dir.join(path.trim_start_matches('/'))
+        
+        let full_path = if path.is_empty() || path == "." {
+            self.root_dir.clone()
+        } else if path.starts_with('/') {
+            PathBuf::from(path)
         } else {
             self.root_dir.join(path)
         };
         
+        info!("resolve_path: full_path={:?}", full_path);
+        
+        if full_path.exists() {
             let canonical_path = full_path.canonicalize()
-            .map_err(|e| anyhow!("Path resolution error: {}", e))?;
+                .map_err(|e| anyhow!("Path resolution error for {:?}: {}", full_path, e))?;
+            
+            info!("resolve_path: canonical_path={:?}", canonical_path);
             
             if !canonical_path.starts_with(&self.root_dir) {
-            return Err(anyhow!("Path traversal attempt detected"));
+                return Err(anyhow!("Path traversal attempt detected: {:?} not under {:?}", canonical_path, self.root_dir));
             }
             
             Ok(canonical_path)
+        } else {
+            if !full_path.starts_with(&self.root_dir) {
+                return Err(anyhow!("Path traversal attempt detected: {:?} not under {:?}", full_path, self.root_dir));
+            }
+            
+            Ok(full_path)
+        }
     }
 
 /// 构建SSH_FXP_VERSION响应（参考OpenSSH sftp-server.c）