shell_command: Use a lock to prevent re-entrant calls

Re-entrant calls to "run" and "run_with_response" would poison the process state resulting in unexpected behavior.  Use a lock to prevent this.

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

moonraker/components/shell_command.py

@@ -11,6 +11,7 @@ import logging
 import signal
 import asyncio
 from tornado import gen
+from tornado.locks import Lock
 from utils import ServerError
 
 # Annotation imports
@@ -146,6 +147,7 @@ class ShellCommand:
         self.proc: Optional[SCProcess] = None
         self.cancelled = False
         self.return_code: Optional[int] = None
+        self.run_lock = Lock()
 
     async def cancel(self, sig_idx: int = 1) -> None:
         self.cancelled = True
@@ -165,6 +167,7 @@ class ShellCommand:
                   log_complete: bool = True,
                   sig_idx: int = 1
                   ) -> bool:
+        async with self.run_lock:
             self.factory.add_running_command(self)
             self._reset_command_data()
             if not timeout:
@@ -198,6 +201,7 @@ class ShellCommand:
                                 log_complete: bool = True,
                                 sig_idx: int = 1
                                 ) -> str:
+        async with self.run_lock:
             self.factory.add_running_command(self)
             retries = max(1, retries)
             while retries > 0:
@@ -217,7 +221,8 @@ class ShellCommand:
                     else:
                         complete = not self.cancelled
                         if self.log_stderr and stderr:
-                        logging.info(f"{self.command[0]}: {stderr.decode()}")
+                            logging.info(
+                                f"{self.command[0]}: {stderr.decode()}")
                     if self._check_proc_success(complete, log_complete):
                         self.factory.remove_running_command(self)
                         return stdout.decode().rstrip("\n")