# 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 cloudinit import signal_handler, subp, util
from cloudinit.cloud import Cloud
from cloudinit.config import Config
from cloudinit.config.schema import MetaSchema
from cloudinit.distros import ALL_DISTROS
from cloudinit.settings import PER_INSTANCE
frequency = PER_INSTANCE
EXIT_FAIL = 254
meta: MetaSchema = {
"id": "cc_power_state_change",
"distros": [ALL_DISTROS],
"frequency": PER_INSTANCE,
"activate_by_schema_keys": ["power_state"],
}
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:
(arg_list, timeout, condition) = load_power_state(cfg, cloud.distro)
if arg_list 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(arg_list))
util.fork_cb(
run_after_pid_gone,
mypid,
cmdline,
timeout,
condition,
execmd,
[arg_list, 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( # nosec B603
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.monotonic() + timeout
def fatal(msg):
LOG.warning(msg)
doexit(EXIT_FAIL)
known_errnos = (errno.ENOENT, errno.ESRCH)
while True:
if time.monotonic() > 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)
# systemd could kill this process with a signal before it exits
# this is expected, so don't crash
with signal_handler.suspend_crash():
func(*args)
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