From 65fbcfa0ba225bd8af292b337484bebece758e88 Mon Sep 17 00:00:00 2001
From: Erik Montnemery <erik@montnemery.com>
Date: Thu, 10 Mar 2022 19:28:00 +0100
Subject: [PATCH] Prevent recursive script calls from deadlocking (#67861)
* Prevent recursive script calls from deadlocking
* Address review comments, improve tests
* Tweak comment
---
homeassistant/helpers/script.py | 23 +++++
tests/components/script/test_init.py | 125 +++++++++++++++++++++++++++
2 files changed, 148 insertions(+)
diff --git a/homeassistant/helpers/script.py b/homeassistant/helpers/script.py
index 1eabc33b89d..07a89c8cddb 100644
--- a/homeassistant/helpers/script.py
+++ b/homeassistant/helpers/script.py
@@ -4,6 +4,7 @@ from __future__ import annotations
import asyncio
from collections.abc import Callable, Sequence
from contextlib import asynccontextmanager, suppress
+from contextvars import ContextVar
from datetime import datetime, timedelta
from functools import partial
import itertools
@@ -126,6 +127,8 @@ SCRIPT_BREAKPOINT_HIT = "script_breakpoint_hit"
SCRIPT_DEBUG_CONTINUE_STOP = "script_debug_continue_stop_{}_{}"
SCRIPT_DEBUG_CONTINUE_ALL = "script_debug_continue_all"
+script_stack_cv: ContextVar[list[int] | None] = ContextVar("script_stack", default=None)
+
def action_trace_append(variables, path):
"""Append a TraceElement to trace[path]."""
@@ -340,6 +343,12 @@ class _ScriptRun:
async def async_run(self) -> None:
"""Run script."""
+ # Push the script to the script execution stack
+ if (script_stack := script_stack_cv.get()) is None:
+ script_stack = []
+ script_stack_cv.set(script_stack)
+ script_stack.append(id(self._script))
+
try:
self._log("Running %s", self._script.running_description)
for self._step, self._action in enumerate(self._script.sequence):
@@ -355,6 +364,8 @@ class _ScriptRun:
script_execution_set("error")
raise
finally:
+ # Pop the script from the script execution stack
+ script_stack.pop()
self._finish()
async def _async_step(self, log_exceptions):
@@ -1218,6 +1229,18 @@ class Script:
else:
variables = cast(dict, run_variables)
+ # Prevent non-allowed recursive calls which will cause deadlocks when we try to
+ # stop (restart) or wait for (queued) our own script run.
+ script_stack = script_stack_cv.get()
+ if (
+ self.script_mode in (SCRIPT_MODE_RESTART, SCRIPT_MODE_QUEUED)
+ and (script_stack := script_stack_cv.get()) is not None
+ and id(self) in script_stack
+ ):
+ script_execution_set("disallowed_recursion_detected")
+ _LOGGER.warning("Disallowed recursion detected")
+ return
+
if self.script_mode != SCRIPT_MODE_QUEUED:
cls = _ScriptRun
else:
diff --git a/tests/components/script/test_init.py b/tests/components/script/test_init.py
index a6923c88aa2..35875c6da12 100644
--- a/tests/components/script/test_init.py
+++ b/tests/components/script/test_init.py
@@ -27,6 +27,13 @@ from homeassistant.core import (
from homeassistant.exceptions import ServiceNotFound
from homeassistant.helpers import template
from homeassistant.helpers.event import async_track_state_change
+from homeassistant.helpers.script import (
+ SCRIPT_MODE_CHOICES,
+ SCRIPT_MODE_PARALLEL,
+ SCRIPT_MODE_QUEUED,
+ SCRIPT_MODE_RESTART,
+ SCRIPT_MODE_SINGLE,
+)
from homeassistant.helpers.service import async_get_all_descriptions
from homeassistant.setup import async_setup_component
import homeassistant.util.dt as dt_util
@@ -790,3 +797,121 @@ async def test_script_restore_last_triggered(hass: HomeAssistant) -> None:
state = hass.states.get("script.last_triggered")
assert state
assert state.attributes["last_triggered"] == time
+
+
+@pytest.mark.parametrize(
+ "script_mode,warning_msg",
+ (
+ (SCRIPT_MODE_PARALLEL, "Maximum number of runs exceeded"),
+ (SCRIPT_MODE_QUEUED, "Disallowed recursion detected"),
+ (SCRIPT_MODE_RESTART, "Disallowed recursion detected"),
+ (SCRIPT_MODE_SINGLE, "Already running"),
+ ),
+)
+async def test_recursive_script(hass, script_mode, warning_msg, caplog):
+ """Test recursive script calls does not deadlock."""
+ # Make sure we cover all script modes
+ assert SCRIPT_MODE_CHOICES == [
+ SCRIPT_MODE_PARALLEL,
+ SCRIPT_MODE_QUEUED,
+ SCRIPT_MODE_RESTART,
+ SCRIPT_MODE_SINGLE,
+ ]
+
+ assert await async_setup_component(
+ hass,
+ "script",
+ {
+ "script": {
+ "script1": {
+ "mode": script_mode,
+ "sequence": [
+ {"service": "script.script1"},
+ {"service": "test.script"},
+ ],
+ },
+ }
+ },
+ )
+
+ service_called = asyncio.Event()
+
+ async def async_service_handler(service):
+ service_called.set()
+
+ hass.services.async_register("test", "script", async_service_handler)
+ hass.states.async_set("input_boolean.test", "on")
+ hass.states.async_set("input_boolean.test2", "off")
+
+ await hass.services.async_call("script", "script1")
+ await asyncio.wait_for(service_called.wait(), 1)
+
+ assert warning_msg in caplog.text
+
+
+@pytest.mark.parametrize(
+ "script_mode,warning_msg",
+ (
+ (SCRIPT_MODE_PARALLEL, "Maximum number of runs exceeded"),
+ (SCRIPT_MODE_QUEUED, "Disallowed recursion detected"),
+ (SCRIPT_MODE_RESTART, "Disallowed recursion detected"),
+ (SCRIPT_MODE_SINGLE, "Already running"),
+ ),
+)
+async def test_recursive_script_indirect(hass, script_mode, warning_msg, caplog):
+ """Test recursive script calls does not deadlock."""
+ # Make sure we cover all script modes
+ assert SCRIPT_MODE_CHOICES == [
+ SCRIPT_MODE_PARALLEL,
+ SCRIPT_MODE_QUEUED,
+ SCRIPT_MODE_RESTART,
+ SCRIPT_MODE_SINGLE,
+ ]
+
+ assert await async_setup_component(
+ hass,
+ "script",
+ {
+ "script": {
+ "script1": {
+ "mode": script_mode,
+ "sequence": [
+ {"service": "script.script2"},
+ ],
+ },
+ "script2": {
+ "mode": script_mode,
+ "sequence": [
+ {"service": "script.script3"},
+ ],
+ },
+ "script3": {
+ "mode": script_mode,
+ "sequence": [
+ {"service": "script.script4"},
+ ],
+ },
+ "script4": {
+ "mode": script_mode,
+ "sequence": [
+ {"service": "script.script1"},
+ {"service": "test.script"},
+ ],
+ },
+ }
+ },
+ )
+
+ service_called = asyncio.Event()
+
+ async def async_service_handler(service):
+ service_called.set()
+
+ hass.services.async_register("test", "script", async_service_handler)
+ hass.states.async_set("input_boolean.test", "on")
+ hass.states.async_set("input_boolean.test2", "off")
+
+ await hass.services.async_call("script", "script1")
+ await asyncio.wait_for(service_called.wait(), 1)
+
+ assert warning_msg in caplog.text