#!/usr/bin/env python3

from __future__ import absolute_import

import errno

import os

import signal

import sys

import time

if os.name == 'nt':

    import ctypes

    _BOOL = ctypes.c_long

    _DWORD = ctypes.c_ulong

    _UINT = ctypes.c_uint

    _HANDLE = ctypes.c_void_p

    ctypes.windll.kernel32.CloseHandle.argtypes = [_HANDLE]

    ctypes.windll.kernel32.CloseHandle.restype = _BOOL

    ctypes.windll.kernel32.GetLastError.argtypes = []

    ctypes.windll.kernel32.GetLastError.restype = _DWORD

    ctypes.windll.kernel32.OpenProcess.argtypes = [_DWORD, _BOOL, _DWORD]

    ctypes.windll.kernel32.OpenProcess.restype = _HANDLE

    ctypes.windll.kernel32.TerminateProcess.argtypes = [_HANDLE, _UINT]

    ctypes.windll.kernel32.TerminateProcess.restype = _BOOL

    ctypes.windll.kernel32.WaitForSingleObject.argtypes = [_HANDLE, _DWORD]

    ctypes.windll.kernel32.WaitForSingleObject.restype = _DWORD

    def _check(ret, expectederr=None):

        if ret == 0:

            winerrno = ctypes.GetLastError()

            if winerrno == expectederr:

                return True

            raise ctypes.WinError(winerrno)

    def kill(pid, logfn, tryhard=True):

        logfn('# Killing daemon process %d' % pid)

        PROCESS_TERMINATE = 1

        PROCESS_QUERY_INFORMATION = 0x400

        SYNCHRONIZE = 0x00100000

        WAIT_OBJECT_0 = 0

        WAIT_TIMEOUT = 258

        WAIT_FAILED = _DWORD(0xFFFFFFFF).value

        handle = ctypes.windll.kernel32.OpenProcess(

            PROCESS_TERMINATE | SYNCHRONIZE | PROCESS_QUERY_INFORMATION,

            False,

            pid,

        )

        if handle is None:

            _check(0, 87)  # err 87 when process not found

            return  # process not found, already finished

        try:

            r = ctypes.windll.kernel32.WaitForSingleObject(handle, 100)

            if r == WAIT_OBJECT_0:

                pass  # terminated, but process handle still available

            elif r == WAIT_TIMEOUT:

                _check(ctypes.windll.kernel32.TerminateProcess(handle, -1))

            elif r == WAIT_FAILED:

                _check(0)  # err stored in GetLastError()

            # TODO?: forcefully kill when timeout

            #        and ?shorter waiting time? when tryhard==True

            r = ctypes.windll.kernel32.WaitForSingleObject(handle, 100)

            # timeout = 100 ms

            if r == WAIT_OBJECT_0:

                pass  # process is terminated

            elif r == WAIT_TIMEOUT:

                logfn('# Daemon process %d is stuck')

            elif r == WAIT_FAILED:

                _check(0)  # err stored in GetLastError()

        except:  # re-raises

            ctypes.windll.kernel32.CloseHandle(handle)  # no _check, keep error

            raise

        _check(ctypes.windll.kernel32.CloseHandle(handle))

else:

    def kill(pid, logfn, tryhard=True):

        try:

            os.kill(pid, 0)

            logfn('# Killing daemon process %d' % pid)

            os.kill(pid, signal.SIGTERM)

            if tryhard:

                for i in range(10):

                    time.sleep(0.05)

                    os.kill(pid, 0)

            else:

                time.sleep(0.1)

                os.kill(pid, 0)

            logfn('# Daemon process %d is stuck - really killing it' % pid)

            os.kill(pid, signal.SIGKILL)

        except OSError as err:

            if err.errno != errno.ESRCH:

                raise

def killdaemons(pidfile, tryhard=True, remove=False, logfn=None):

    if not logfn:

        logfn = lambda s: s

    # Kill off any leftover daemon processes

    try:

        pids = []

        with open(pidfile) as fp:

            for line in fp:

                try:

                    pid = int(line)

                    if pid <= 0:

                        raise ValueError

                except ValueError:

                    logfn(

                        '# Not killing daemon process %s - invalid pid'

                        % line.rstrip()

                    )

                    continue

                pids.append(pid)

        for pid in pids:

            kill(pid, logfn, tryhard)

        if remove:

            os.unlink(pidfile)

    except IOError:

        pass

if __name__ == '__main__':

    if len(sys.argv) > 1:

        (path,) = sys.argv[1:]

    else:

        path = os.environ["DAEMON_PIDS"]

    killdaemons(path, remove=True)