shell: handle PermissionError when reading history file

Print a warning with a hint on how to clear extended attributes
instead of silently ignoring the error.

Signed-off-by: a-ramses <[email protected]>

Author: a-ramses

proxyclient/m1n1/shell.py

@@ -27,6 +27,11 @@ def init_history(self, histfile):
                 readline.read_history_file(histfile)
             except FileNotFoundError:
                 pass
+            except PermissionError as e:
+                print(f"Failed reading history from {histfile}: {e}", file=sys.stderr)
+                if sys.platform == "darwin":
+                    print(f"  On macOS this may be caused by extended attributes. "
+                          f"Try: xattr -c {histfile}", file=sys.stderr)
 
     def save_history(self):
         readline.set_history_length(10000)