tests/killdaemons.py

import-checker: make stdlib path detection work in virtual environments

The previous logic tried to find the directory containing BaseHTTPServer, which
didn’t work as indended because it was only present on Python 2. Instead, the
argparse module is used now.

#!/usr/bin/env python3

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 ProcessLookupError:
            pass


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)