agent: support copying of directories and symlinks

This patch allows copying of directories and symlinks when
static file copying is used between host and guest. This change is
necessary to support recursive file copying between shim and agent.

Signed-off-by: Yohei Ueda <yohei@jp.ibm.com>

src/agent/src/rpc.rs

@@ -1989,6 +1989,38 @@ fn do_copy_file(req: &CopyFileRequest) -> Result<()> {
 
     std::fs::set_permissions(&dir, std::fs::Permissions::from_mode(req.dir_mode))?;
 
+    let sflag = stat::SFlag::from_bits_truncate(req.file_mode);
+
+    if sflag.contains(stat::SFlag::S_IFDIR) {
+        fs::create_dir(path.clone()).or_else(|e| {
+            if e.kind() != std::io::ErrorKind::AlreadyExists {
+                return Err(e);
+            }
+            Ok(())
+        })?;
+
+        std::fs::set_permissions(path.clone(), std::fs::Permissions::from_mode(req.file_mode))?;
+
+        unistd::chown(
+            &path,
+            Some(Uid::from_raw(req.uid as u32)),
+            Some(Gid::from_raw(req.gid as u32)),
+        )?;
+
+        return Ok(());
+    }
+
+    if sflag.contains(stat::SFlag::S_IFLNK) {
+        let src = PathBuf::from(String::from_utf8(req.data.clone()).unwrap());
+
+        unistd::symlinkat(&src, None, &path)?;
+        let path_str = CString::new(path.to_str().unwrap())?;
+        let ret = unsafe { libc::lchown(path_str.as_ptr(), req.uid as u32, req.gid as u32) };
+        Errno::result(ret).map(drop)?;
+
+        return Ok(());
+    }
+
     let mut tmpfile = path.clone();
     tmpfile.set_extension("tmp");