# 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

------------------

**Summary:** change power state

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. The ``power_state`` config

key accepts a dict of options. If ``mode`` is any value other than

``poweroff``, ``halt``, or ``reboot``, then no action will be taken.

The system

can be shutdown before cloud-init has finished using the ``timeout`` option.

The ``delay`` key specifies a duration to be added onto any shutdown command

used. Therefore, if a 5 minute delay and a 120 second shutdown are specified,

the maximum amount of time between cloud-init starting and the system shutting

down is 7 minutes, and the minimum amount of time is 5 minutes. The ``delay``

key must have an argument in either the form ``+5`` for 5 minutes or ``now``

for immediate shutdown.

Optionally, a command can be run to determine whether or not

the system should shut down. The command to be run should be specified in the

``condition`` key. For command formatting, see the documentation for

``cc_runcmd``. The specified shutdown behavior will only take place if the

``condition`` key is omitted or the command specified by the ``condition``

key returns 0.

.. note::

    With Alpine Linux any message value specified is ignored as Alpine's halt,

    poweroff, and reboot commands do not support broadcasting a message.

**Internal name:** ``cc_power_state_change``

**Module frequency:** per instance

**Supported distros:** all

**Config keys**::

    power_state:

        delay: <now/'+minutes'>

        mode: <poweroff/halt/reboot>

        message: <shutdown message>

        timeout: <seconds>

        condition: <true/false/command>

"""

import errno

import os

import re

import subprocess

import time

from cloudinit.settings import PER_INSTANCE

from cloudinit import subp

from cloudinit import util

frequency = PER_INSTANCE

EXIT_FAIL = 254

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_file("/proc/%s/cmdline" % pid)

    except IOError:

        return None

def check_condition(cond, log=None):

    if isinstance(cond, bool):

        if log:

            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:

            if log:

                log.debug(pre + "exited 0. condition met.")

            return True

        elif ret == 1:

            if log:

                log.debug(pre + "exited 1. condition not met.")

            return False

        else:

            if log:

                log.warning(pre + "unexpected exit %s. " % ret +

                            "do not apply change.")

            return False

    except Exception as e:

        if log:

            log.warning(pre + "Unexpected error: %s" % e)

        return False

def handle(_name, cfg, cloud, log, _args):

    try:

        (args, timeout, condition) = load_power_state(cfg, cloud.distro.name)

        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, log,

                 condition, execmd, [args, devnull_fp])

def convert_delay(delay, fmt=None, scale=None):

    if not fmt:

        fmt = "+%s"

    if not scale:

        scale = 1

    if delay != "now":

        delay = fmt % int(int(delay) * int(scale))

    return delay

def load_power_state(cfg, distro_name):

    # 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.")

    opt_map = {'halt': '-H', 'poweroff': '-P', 'reboot': '-r'}

    mode = pstate.get("mode")

    if mode not in opt_map:

        raise TypeError(

            "power_state[mode] required, must be one of: %s. found: '%s'." %

            (','.join(opt_map.keys()), mode))

    delay = pstate.get("delay", "now")

    message = pstate.get("message")

    scale = 1

    fmt = "+%s"

    command = ["shutdown", opt_map[mode]]

    if distro_name == 'alpine':

        # Convert integer 30 or string '30' to '1800' (seconds) as Alpine's

        # halt/poweroff/reboot commands take seconds rather than minutes.

        scale = 60

        # No "+" in front of delay value as not supported by Alpine's commands.

        fmt = "%s"

        if delay == "now":

            # Alpine's commands do not understand "now".

            delay = "0"

        command = [mode, "-d"]

        # Alpine's commands don't support a message.

        message = None

    try:

        delay = convert_delay(delay, fmt=fmt, scale=scale)

    except ValueError as e:

        raise TypeError(

            "power_state[delay] must be 'now' or '+m' (minutes)."

            " found '%s'." % delay

        ) from e

    args = command + [delay]

    if message:

        args.append(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, log, 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):

        if log:

            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(.25)

    if not msg:

        fatal("Unexpected error in run_after_pid_gone")

    if log:

        log.debug(msg)

    try:

        if not check_condition(condition, log):

            return

    except Exception as e:

        fatal("Unexpected Exception when checking condition: %s" % e)

    func(*args)

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