unftp-sbe-fs: don't panic during Filesystem::new

Filesystem::new will now return an error if it can't open the root
directory.  However, ServerExt::with_fs will still panic because the
ServerBuilder is required to be infalliable.

crates/unftp-sbe-fs/examples/cap-ftpd-worker.rs

@@ -241,7 +241,7 @@ async fn main() {
     let auth = Arc::new(JsonFileAuthenticator::from_file(args[1].clone()).unwrap());
     // XXX This would be a lot easier if the libunftp API allowed creating the
     // storage just before calling service.
-    let storage = Mutex::new(Some(Filesystem::new(std::env::temp_dir())));
+    let storage = Mutex::new(Some(Filesystem::new(std::env::temp_dir()).unwrap()));
     let sgen = Box::new(move || storage.lock().unwrap().take().unwrap());
 
     let mut sb = libunftp::ServerBuilder::with_authenticator(sgen, auth);

crates/unftp-sbe-fs/src/ext.rs

@@ -19,7 +19,10 @@ pub trait ServerExt {
         let p = path.into();
         libunftp::ServerBuilder::new(Box::new(move || {
             let p = &p.clone();
-            Filesystem::new(p)
+            match Filesystem::new(p) {
+                Ok(fs) => fs,
+                Err(e) => panic!("Cannot open file system root {}: {}", p.display(), e),
+            }
         }))
     }
 }

crates/unftp-sbe-fs/src/lib.rs

@@ -80,11 +80,11 @@ impl Filesystem {
     /// Create a new Filesystem backend, with the given root. No operations can take place outside
     /// of the root. For example, when the `Filesystem` root is set to `/srv/ftp`, and a client
     /// asks for `hello.txt`, the server will send it `/srv/ftp/hello.txt`.
-    pub fn new<P: Into<PathBuf>>(root: P) -> Self {
+    pub fn new<P: Into<PathBuf>>(root: P) -> io::Result<Self> {
         let path = root.into();
         let aa = cap_std::ambient_authority();
-        let root_fd = Arc::new(cap_std::fs::Dir::open_ambient_dir(&path, aa).unwrap());
-        Filesystem { root_fd, root: path }
+        let root_fd = Arc::new(cap_std::fs::Dir::open_ambient_dir(&path, aa)?);
+        Ok(Filesystem { root_fd, root: path })
     }
 }
 

crates/unftp-sbe-fs/src/tests.rs

@@ -23,7 +23,7 @@ fn fs_stat() {
     let meta = file.metadata().unwrap();
 
     // Create a filesystem StorageBackend with the directory containing our temp file as root
-    let fs = Filesystem::new(&root);
+    let fs = Filesystem::new(&root).unwrap();
 
     // Since the filesystem backend is based on futures, we need a runtime to run it
     let rt = tokio::runtime::Builder::new_current_thread().build().unwrap();
@@ -48,7 +48,7 @@ fn fs_list() {
     let meta = file.metadata().unwrap();
 
     // Create a filesystem StorageBackend with our root dir
-    let fs = Filesystem::new(root.path());
+    let fs = Filesystem::new(root.path()).unwrap();
 
     // Since the filesystem backend is based on futures, we need a runtime to run it
     let rt = tokio::runtime::Builder::new_current_thread().build().unwrap();
@@ -74,7 +74,7 @@ fn fs_list_fmt() {
     let relpath = path.strip_prefix(root.path()).unwrap();
 
     // Create a filesystem StorageBackend with our root dir
-    let fs = Filesystem::new(root.path());
+    let fs = Filesystem::new(root.path()).unwrap();
 
     let rt = tokio::runtime::Builder::new_current_thread().build().unwrap();
     let my_list = rt.block_on(fs.list_fmt(&DefaultUser {}, "/")).unwrap();
@@ -96,7 +96,7 @@ fn fs_get() {
     file.write_all(data).unwrap();
 
     let filename = path.file_name().unwrap();
-    let fs = Filesystem::new(&root);
+    let fs = Filesystem::new(&root).unwrap();
 
     // Since the filesystem backend is based on futures, we need a runtime to run it
     let rt = Runtime::new().unwrap();
@@ -117,7 +117,7 @@ fn fs_get() {
 fn fs_put() {
     let root = std::env::temp_dir();
     let orig_content = b"hallo";
-    let fs = Filesystem::new(&root);
+    let fs = Filesystem::new(&root).unwrap();
 
     // Since the Filesystem StorageBackend is based on futures, we need a runtime to run them
     // to completion
@@ -178,7 +178,7 @@ fn fileinfo_fmt() {
 #[test]
 fn fs_mkd() {
     let root = tempfile::TempDir::new().unwrap().into_path();
-    let fs = Filesystem::new(&root);
+    let fs = Filesystem::new(&root).unwrap();
     let new_dir_name = "bla";
 
     // Since the Filesystem StorageBackend is based on futures, we need a runtime to run them
@@ -203,7 +203,7 @@ fn fs_rename_file() {
     // to completion
     let rt = Runtime::new().unwrap();
 
-    let fs = Filesystem::new(&root);
+    let fs = Filesystem::new(&root).unwrap();
     let r = rt.block_on(fs.rename(&DefaultUser {}, &old_filename, &new_filename));
     assert!(r.is_ok());
 
@@ -225,7 +225,7 @@ fn fs_rename_dir() {
     // to completion
     let rt = Runtime::new().unwrap();
 
-    let fs = Filesystem::new(&root);
+    let fs = Filesystem::new(&root).unwrap();
     let r = rt.block_on(fs.rename(&DefaultUser {}, &old_dir, &new_dir));
     assert!(r.is_ok());
 
@@ -247,7 +247,7 @@ fn fs_md5() {
     let mut file = file.as_file();
 
     // Create a filesystem StorageBackend with the directory containing our temp file as root
-    let fs = Filesystem::new(&root);
+    let fs = Filesystem::new(&root).unwrap();
     file.write_all(DATA.as_bytes()).unwrap();
 
     // Since the filesystem backend is based on futures, we need a runtime to run it