name : cc_power_state_change.py # Copyright (C) 2011 Canonical Ltd. # # Author: Scott Moser <scott.moser@canonical.com> # # This file is part of cloud-init. See LICENSE file for license information. """Power State Change: Change power state""" import errno import logging import os import re import subprocess import time from textwrap import dedent from cloudinit import subp, util from cloudinit.cloud import Cloud from cloudinit.config import Config from cloudinit.config.schema import MetaSchema, get_meta_doc from cloudinit.distros import ALL_DISTROS from cloudinit.settings import PER_INSTANCE frequency = PER_INSTANCE EXIT_FAIL = 254 MODULE_DESCRIPTION = """\ This module handles shutdown/reboot after all config modules have been run. By default it will take no action, and the system will keep running unless a package installation/upgrade requires a system reboot (e.g. installing a new kernel) and ``package_reboot_if_required`` is true. Using this module ensures that cloud-init is entirely finished with modules that would be executed. An example to distinguish delay from timeout: If you delay 5 (5 minutes) and have a timeout of 120 (2 minutes), then the max time until shutdown will be 7 minutes, though it could be as soon as 5 minutes. Cloud-init will invoke 'shutdown +5' after the process finishes, or when 'timeout' seconds have elapsed. .. note:: With Alpine Linux any message value specified is ignored as Alpine's halt, poweroff, and reboot commands do not support broadcasting a message. """ meta: MetaSchema = { "id": "cc_power_state_change", "name": "Power State Change", "title": "Change power state", "description": MODULE_DESCRIPTION, "distros": [ALL_DISTROS], "frequency": PER_INSTANCE, "examples": [ dedent( """\ power_state: delay: now mode: poweroff message: Powering off timeout: 2 condition: true """ ), dedent( """\ power_state: delay: 30 mode: reboot message: Rebooting machine condition: test -f /var/tmp/reboot_me """ ), ], "activate_by_schema_keys": ["power_state"], } __doc__ = get_meta_doc(meta) LOG = logging.getLogger(__name__) def givecmdline(pid): # Returns the cmdline for the given process id. In Linux we can use procfs # for this but on BSD there is /usr/bin/procstat. try: # Example output from procstat -c 1 # PID COMM ARGS # 1 init /bin/init -- if util.is_FreeBSD(): (output, _err) = subp.subp(["procstat", "-c", str(pid)]) line = output.splitlines()[1] m = re.search(r"\d+ (\w|\.|-)+\s+(/\w.+)", line) return m.group(2) else: return util.load_text_file("/proc/%s/cmdline" % pid) except IOError: return None def check_condition(cond): if isinstance(cond, bool): LOG.debug("Static Condition: %s", cond) return cond pre = "check_condition command (%s): " % cond try: proc = subprocess.Popen(cond, shell=not isinstance(cond, list)) proc.communicate() ret = proc.returncode if ret == 0: LOG.debug("%sexited 0. condition met.", pre) return True elif ret == 1: LOG.debug("%sexited 1. condition not met.", pre) return False else: LOG.warning("%sunexpected exit %s. do not apply change.", pre, ret) return False except Exception as e: LOG.warning("%sUnexpected error: %s", pre, e) return False def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None: try: (args, timeout, condition) = load_power_state(cfg, cloud.distro) if args is None: LOG.debug("no power_state provided. doing nothing") return except Exception as e: LOG.warning("%s Not performing power state change!", str(e)) return if condition is False: LOG.debug("Condition was false. Will not perform state change.") return mypid = os.getpid() cmdline = givecmdline(mypid) if not cmdline: LOG.warning("power_state: failed to get cmdline of current process") return devnull_fp = open(os.devnull, "w") LOG.debug("After pid %s ends, will execute: %s", mypid, " ".join(args)) util.fork_cb( run_after_pid_gone, mypid, cmdline, timeout, condition, execmd, [args, devnull_fp], ) def load_power_state(cfg, distro): # returns a tuple of shutdown_command, timeout # shutdown_command is None if no config found pstate = cfg.get("power_state") if pstate is None: return (None, None, None) if not isinstance(pstate, dict): raise TypeError("power_state is not a dict.") modes_ok = ["halt", "poweroff", "reboot"] mode = pstate.get("mode") if mode not in distro.shutdown_options_map: raise TypeError( "power_state[mode] required, must be one of: %s. found: '%s'." % (",".join(modes_ok), mode) ) args = distro.shutdown_command( mode=mode, delay=pstate.get("delay", "now"), message=pstate.get("message"), ) try: timeout = float(pstate.get("timeout", 30.0)) except ValueError as e: raise ValueError( "failed to convert timeout '%s' to float." % pstate["timeout"] ) from e condition = pstate.get("condition", True) if not isinstance(condition, (str, list, bool)): raise TypeError("condition type %s invalid. must be list, bool, str") return (args, timeout, condition) def doexit(sysexit): os._exit(sysexit) def execmd(exe_args, output=None, data_in=None): ret = 1 try: proc = subprocess.Popen( exe_args, stdin=subprocess.PIPE, stdout=output, stderr=subprocess.STDOUT, ) proc.communicate(data_in) ret = proc.returncode except Exception: doexit(EXIT_FAIL) doexit(ret) def run_after_pid_gone(pid, pidcmdline, timeout, condition, func, args): # wait until pid, with /proc/pid/cmdline contents of pidcmdline # is no longer alive. After it is gone, or timeout has passed # execute func(args) msg = None end_time = time.time() + timeout def fatal(msg): LOG.warning(msg) doexit(EXIT_FAIL) known_errnos = (errno.ENOENT, errno.ESRCH) while True: if time.time() > end_time: msg = "timeout reached before %s ended" % pid break try: cmdline = givecmdline(pid) if cmdline != pidcmdline: msg = "cmdline changed for %s [now: %s]" % (pid, cmdline) break except IOError as ioerr: if ioerr.errno in known_errnos: msg = "pidfile gone [%d]" % ioerr.errno else: fatal("IOError during wait: %s" % ioerr) break except Exception as e: fatal("Unexpected Exception: %s" % e) time.sleep(0.25) if not msg: fatal("Unexpected error in run_after_pid_gone") LOG.debug(msg) try: if not check_condition(condition): return except Exception as e: fatal("Unexpected Exception when checking condition: %s" % e) func(*args)