little update.

libmxclient/determinant/mxpassfile/readpassfile_unix.go

@@ -0,0 +1,22 @@
+//go:build !windows
+// +build !windows
+
+package mxpassfile
+
+import (
+	"errors"
+	"os"
+)
+
+// ReadPassfile reads the file at path and parses it into a Passfile.
+func ReadPassfile(path string) (*Passfile, error) {
+	fileInfo, err := os.Stat(path)
+	if err != nil {
+		return nil, err
+	}
+	permissions := fileInfo.Mode().Perm()
+	if permissions != 0o600 {
+		return nil, errors.New("To wide permissions, ignore file")
+	}
+	return readPassfile(path)
+}