Preserve symlinks in file copy

src/bin/dosh-server.rs

@@ -2681,6 +2681,46 @@ async fn handle_file_request(
             send_file_response_to_client(state, socket, client_id, stream_id, FileResponse::Ok)
                 .await
         }
+        FileRequest::Readlink { path } => {
+            let path = clean_remote_path(&path, home)?;
+            let target =
+                fs::read_link(&path).with_context(|| format!("readlink {}", path.display()))?;
+            let target = target
+                .to_str()
+                .ok_or_else(|| anyhow!("symlink target is not valid UTF-8"))?
+                .to_string();
+            send_file_response_to_client(
+                state,
+                socket,
+                client_id,
+                stream_id,
+                FileResponse::LinkTarget { target },
+            )
+            .await
+        }
+        FileRequest::Symlink {
+            path,
+            target,
+            overwrite,
+        } => {
+            let path = clean_remote_path(&path, home)?;
+            if let Some(parent) = path.parent() {
+                fs::create_dir_all(parent)
+                    .with_context(|| format!("create {}", parent.display()))?;
+            }
+            if let Ok(metadata) = fs::symlink_metadata(&path) {
+                anyhow::ensure!(overwrite, "destination exists: {}", path.display());
+                anyhow::ensure!(
+                    !metadata.is_dir(),
+                    "destination is a directory: {}",
+                    path.display()
+                );
+                fs::remove_file(&path).with_context(|| format!("remove {}", path.display()))?;
+            }
+            create_symlink(&target, &path)?;
+            send_file_response_to_client(state, socket, client_id, stream_id, FileResponse::Ok)
+                .await
+        }
         FileRequest::Remove { path, recursive } => {
             let path = clean_remote_path(&path, home)?;
             let metadata =
@@ -3065,6 +3105,17 @@ fn set_mode(path: &Path, mode: u32) -> Result<()> {
     fs::set_permissions(path, permissions).with_context(|| format!("chmod {}", path.display()))
 }
 
+#[cfg(unix)]
+fn create_symlink(target: &str, path: &Path) -> Result<()> {
+    std::os::unix::fs::symlink(target, path)
+        .with_context(|| format!("symlink {} -> {}", path.display(), target))
+}
+
+#[cfg(not(unix))]
+fn create_symlink(_target: &str, _path: &Path) -> Result<()> {
+    bail!("symlink creation is not supported on this server platform")
+}
+
 fn upload_temp_path(final_path: &Path, stream_id: u64) -> PathBuf {
     let name = final_path
         .file_name()