#!/usr/bin/python
__author__ = 'iseletsk'

#Copyright (c) 2014 Cloud Linux Zug GbhT
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENCE.TXT

import urllib2
import os
try:
    import gpgme, gpgme.editutil #todo: not available on ubuntu
except ImportError:
    gpgme= None

import time  #todo: not available on ubuntu
from datetime import datetime
import subprocess
import logging
import logging.handlers
import glob
import shutil
import platform
import base64
import ConfigParser

kcarelog = logging.getLogger("kcare")
if os.path.exists('/dev/log'):
    try:
        kcarelog.setLevel(logging.INFO)
        handler = logging.handlers.SysLogHandler(address='/dev/log', facility=logging.handlers.SysLogHandler.LOG_USER)
        formatter = logging.Formatter('kcare: %(message)s')
        handler.setFormatter(formatter)
        kcarelog.addHandler(handler)
    except:
        pass

VERSION="1.7-2"
KERNEL_VERSION_FILE="/proc/version"
PATCH_SERVER_PROTOCOL = "http://"
PATCH_SERVER="patches.kernelcare.com"
PATCH_METHOD='FREEZE'
PATCH_SERVER_URL=PATCH_SERVER_PROTOCOL+PATCH_SERVER
REGISTRATION_API_URL='https://cln.cloudlinux.com/api/kcare'
TEST_PREFIX=''
PATCH_BIN="/kpatch.bin"
PATCH_INFO="/kpatch.info"
BLACKLIST_FILE="/kpatch.blacklist"
KMOD_BIN="kcare.ko"
PATCH_DONE="/.done"
PATCH_CACHE="/var/cache/kcare"
PATCH_LATEST="latest.v1"
DOWNLOAD_CHUNK=16*1024
CONFIG='/etc/sysconfig/kcare/kcare.conf'
FREEZER_BLACKLIST='/etc/sysconfig/kcare/freezer.modules.blacklist'
SYSTEMID='/etc/sysconfig/kcare/systemid'
KCARE_DEV='/dev/kcare'
GPG_KEY_DIR='/etc/pki/kcare-gpg/'
GPG_KEY_ID='KernelCare <info@kernelcare.com>'
CACHE_ENTRIES=3
KPATCH_CTL='/usr/libexec/kcare/kpatch_ctl'
VIRTWHAT='/usr/libexec/kcare/virt-what'


BLACKLIST_START = "==BLACKLIST==\n"
BLACKLIST_END = "==END BLACKLIST==\n"

BLACKLIST_MODULES = ['ksplice', 'kpatch']
KCARE_UNAME_FILE='/proc/kcare/effective_version'

# allowed values: REMOTE, LOCAL, LOCAL_FIRST
UPDATE_POLICY="REMOTE"
AUTO_UPDATE=True


AWS = {
    "region": "",
    "bucket": "",
    "prefix": "",
    "access_key": "",
    "secret_key": ""
}
AWS_USE = False

PRINT_INFO=1
PRINT_WARN=2
PRINT_ERROR=3

print_level=PRINT_INFO

def set_print_level(level):
    global print_level
    print_level = level

GPG_BIN='/usr/bin/gpg'


# define emulate functools.wraps

def partial(func, *args, **kwds):
    "Emulate Python2.6's functools.partial"
    return lambda *fargs, **fkwds: func(*(args+fargs), **dict(kwds, **fkwds))
WRAPPER_ASSIGNMENTS = ('__module__', '__name__', '__doc__')
WRAPPER_UPDATES = ('__dict__',)

def get_freezer_blacklist():
    result = set()
    try:
        f = open(FREEZER_BLACKLIST, 'r')
        for line in f:
            result.add(line.rstrip())
        f.close()
    except:
        pass
    return result

def update_wrapper(wrapper,
                   wrapped,
                   assigned = WRAPPER_ASSIGNMENTS,
                   updated = WRAPPER_UPDATES):
    """Update a wrapper function to look like the wrapped function

       wrapper is the function to be updated
       wrapped is the original function
       assigned is a tuple naming the attributes assigned directly
       from the wrapped function to the wrapper function (defaults to
       functools.WRAPPER_ASSIGNMENTS)
       updated is a tuple naming the attributes off the wrapper that
       are updated with the corresponding attribute from the wrapped
       function (defaults to functools.WRAPPER_UPDATES)
    """
    for attr in assigned:
        setattr(wrapper, attr, getattr(wrapped, attr))
    for attr in updated:
        getattr(wrapper, attr).update(getattr(wrapped, attr, {}))
    # Return the wrapper so this can be used as a decorator via partial()
    return wrapper

def wraps(wrapped,
          assigned = WRAPPER_ASSIGNMENTS,
          updated = WRAPPER_UPDATES):
    """Decorator factory to apply update_wrapper() to a wrapper function

       Returns a decorator that invokes update_wrapper() with the decorated
       function as the wrapper argument and the arguments to wraps() as the
       remaining arguments. Default arguments are as for update_wrapper().
       This is a convenience function to simplify applying partial() to
       update_wrapper().
    """
    return partial(update_wrapper, wrapped=wrapped,
                   assigned=assigned, updated=updated)

# end of wraps

def printinfo(message, level):
    global print_level
    if print_level <= level:
        print message

def loginfo(message):
    printinfo(message, PRINT_INFO)
    kcarelog.info(message)

def logerror(message):
    printinfo(message, PRINT_ERROR)
    kcarelog.error(message)


# source http://www.saltycrane.com/blog/2009/11/trying-out-retry-decorator-python/
def retry(ExceptionToCheck, tries=4, delay=3, backoff=2, logger=None):
    """Retry calling the decorated function using an exponential backoff.

    http://www.saltycrane.com/blog/2009/11/trying-out-retry-decorator-python/
    original from: http://wiki.python.org/moin/PythonDecoratorLibrary#Retry

    :param ExceptionToCheck: the exception to check. may be a tuple of
        exceptions to check
    :type ExceptionToCheck: Exception or tuple
    :param tries: number of times to try (not retry) before giving up
    :type tries: int
    :param delay: initial delay between retries in seconds
    :type delay: int
    :param backoff: backoff multiplier e.g. value of 2 will double the delay
        each retry
    :type backoff: int
    :param logger: logger to use. If None, print
    :type logger: logging.Logger instance
    """
    def deco_retry(f):

        @wraps(f)
        def f_retry(*args, **kwargs):
            mtries, mdelay = tries, delay
            while mtries > 1:
                try:
                    return f(*args, **kwargs)
                except ExceptionToCheck, e:
                    msg = "%s, Retrying in %d seconds..." % (str(e), mdelay)
                    if logger:
                        logger.warning(msg)
                    else:
                        print msg
                    time.sleep(mdelay)
                    mtries -= 1
                    mdelay *= backoff
            return f(*args, **kwargs)

        return f_retry  # true decorator

    return deco_retry

def get_cache_path(hash, patch_level, name):
    return PATCH_CACHE + "/" + hash + "/" + patch_level + name

def get_cache_latest_name(hash):
    return PATCH_CACHE + "/" + hash + "/latest"

def save_cache_latest(hash, patch_level):
    out = open(get_cache_latest_name(hash), 'w')
    out.write(patch_level)
    out.close()

def get_cache_latest(hash):
    if os.path.isfile(get_cache_latest_name(hash)):
        try:
            return open(get_cache_latest_name(hash), 'r').read()
        except:
            pass
    return -1

def get_kmod_path(hash):
    return PATCH_CACHE + "/"+hash+"/"+KMOD_BIN

class NotAuthorizedException(Exception):
    def __init__(self):
        Exception.__init__(self, "Invalid License")

class UnknownKernelException(Exception):
    def __init__(self):
        Exception.__init__(self, "Unknown Kernel (%s %s)" % (get_distro()[0], platform.release()))

class UnableToGetLicenseException(Exception):
    def __init__(self, code):
        Exception.__init__(self, "Unknown Issue when getting trial license, error code: "+str(code))


class NoTrialException(Exception):
    def __init__(self):
        Exception.__init__(self, "Not Authorized")

class AlreadyTrialedException(Exception):
    def __init__(self, ip, created):
        created = created[0:created.index('T')]
        Exception.__init__(self, "The IP %s was already used for trialing on %s " % (ip, created))

def http_request(url, auth_string):
    request = urllib2.Request(url)
    if auth_string:
        request.add_header("Authorization", "Basic %s" % auth_string)
    return request

def check_access():
    url = PATCH_SERVER_URL + TEST_PREFIX + "/" + PATCH_LATEST
    try:
        urllib2.urlopen(http_request(url, get_httpauth_string()))
    except urllib2.HTTPError, e:
        if e.code == 403:
            return 0
        if e.code == 404:
            return 1
        logerror("Unknown Error retrieving license information")
        return -1
    return 1

def print_cln_http_error(e):
    logerror("Unable to connect to the %s, please, try again later (%d)" % (REGISTRATION_API_URL, e.code))

def parse_response_date(str):
    str = str[0:str.index('T')]
    if hasattr(datetime, 'strptime'):
        pdate = datetime.strptime(str, "%Y-%m-%d")
    else:
        pdate = datetime(*(time.strptime(str, "%Y-%m-%d")[:6]))
    return pdate

def license_info():
    server_id = get_serverid()
    if server_id:
        try:
            response = urllib2.urlopen(REGISTRATION_API_URL+'/check.plain?server_id=%s' % server_id)
            res = parse_plain(response.read())
            code = int(res['code'])
            if code == 0:
                print "Key based valid license found"
            else:
                if not _get_license_info_by_ip(key_checked=1):
                    print "No valid key based license found"
        except urllib2.HTTPError, e:
            print_cln_http_error(e)
    else:
        _get_license_info_by_ip()

def _get_license_info_by_ip(key_checked=0):
    try:
        response = urllib2.urlopen(REGISTRATION_API_URL+'/check.plain')
        res = parse_plain(response.read())
        if res['success'].lower() == 'true':
            code = int(res['code'])
            if code == 0:
                print "Valid license found for ip %s" % (res['ip'])
                return True
            if code == 1:
                ip = res['ip']
                expires_str = parse_response_date(res['expire_date']).strftime("%Y-%m-%d")
                print "You have a trial license for the IP %s that will expire on %s" % (ip, expires_str)
                return True
            if code == 2 and key_checked == 0:
                ip = res['ip']
                expires_str = parse_response_date(res['expire_date']).strftime("%Y-%m-%d")
                print "Your trial license for the IP %s expired on on %s" % (ip, expires_str)
            if code == 3 and key_checked == 0:
                if hasattr(res, 'ip'):
                    print "The IP %s hasn't been licensed" % (res['ip'])
                else:
                    print "This server hasn't been licensed"
        else:
            if hasattr(res, 'message'):
                message = res['message']
            else:
                message = ''
            print "Error retrieving license info %s" % (message)
    except urllib2.HTTPError, e:
        print_cln_http_error(e)
    except KeyError, ke:
        print "Unknown Key: ", ke
    return False

def register_trial(ip):
    try:
        response = urllib2.urlopen(REGISTRATION_API_URL+'/trial.plain')
        res = parse_plain(response.read())
        try:
            if res['success'].lower() == "true":
                if res['expired'] == 'true':
                    raise AlreadyTrialedException(res['ip'], res['created'])
                print "Requesting trial license for %s, please wait..." % res['ip']
                return None
            elif res['success'] == "na":
                raise NotAuthorizedException()
            else:
                raise UnableToGetLicenseException(-1) # Invalid response?
        except KeyError, ke:
            raise UnableToGetLicenseException(ke)
    except urllib2.HTTPError, e:
        raise UnableToGetLicenseException(e.code)


def get_distro():
    if hasattr(platform, 'linux_distribution'):
        return platform.linux_distribution()
    else:
        return platform.dist()


def server_info():
    hash={}
    hash['machine']=platform.machine()
    hash['node']=platform.node()
    hash['processor']=platform.processor()
    hash['release']=platform.release()
    hash['system']=platform.system()
    hash['version']=platform.version()
    distro = get_distro()
    hash['distro']=distro[0]
    hash['distro_version']=distro[1]
    hash['euname']=kcare_uname()
    hash['patch_level']=loaded_patch_level()
    hash['virt']=check_output([VIRTWHAT])
    hash['kcare_version']=VERSION
    server_id = get_serverid()
    if server_id:
        hash['server_id'] = get_serverid()
    return base64.b16encode(str(hash))


def get_httpauth_string():
    server_id = get_serverid()
    if server_id:
        return base64.encodestring('%s:%s' % (server_id, 'kernelcare')).replace('\n', '')
    return None


class PatchFetcher:
    def __init__(self, _hash, patch_level=None):
        self.hash = _hash
        self.server = PATCH_SERVER_URL+TEST_PREFIX+"/"+_hash + "/"
        self.auth_string = get_httpauth_string()
        if patch_level is None:
            self.get_latest_patch_level()
        else:
            self.patch_level = patch_level

    def _request(self, url):
        return http_request(url, self.auth_string)

    @retry(urllib2.URLError, tries=4, delay=3, backoff=2, logger=kcarelog)
    def get_latest_patch_level(self):
        url = self.server + PATCH_LATEST + "?" + server_info()
        try:
            response = urllib2.urlopen(self._request(url))
        except urllib2.HTTPError, e:
            if e.code == 404:
                raise UnknownKernelException()
            if e.code == 403:
                ip = e.read()
                register_trial(ip)
                raise e
            else: raise e
        self.patch_level = response.read().rstrip('\n')

    def _get_cache_path(self, name):
        return get_cache_path(self.hash, self.patch_level, name)

    def fetch_patch_file(self, name, check_signature=False):
        url = self.server  + self.patch_level+name
        dst = self._get_cache_path(name)
        return self.fetch_url(url, dst, check_signature)

    def fetch_kmod(self):
        url = self.server + KMOD_BIN
        dst = get_kmod_path(self.hash)
        return self.fetch_url(url, dst, True)

    def save_file(self, response, dst):
        fp = open(dst, "wb")
        try:
            while True:
                chunk = response.read(DOWNLOAD_CHUNK)
                if not chunk: break
                fp.write(chunk)
        finally:
            fp.close()

    @retry(urllib2.URLError, tries=4, delay=3, backoff=2)
    def fetch_url(self, url, dst, check_signature=False):
        response = urllib2.urlopen(self._request(url))
        self.save_file(response, dst)
        if check_signature:
            os.environ['GNUPGHOME'] = GPG_KEY_DIR
            response = urllib2.urlopen(self._request(url+".sig"))
            if gpgme is None:
                check_gpg_bin()
                sig_dst = dst+'.sig'
                self.save_file(response, sig_dst)
                if subprocess.call([GPG_BIN, '--verify', sig_dst, dst], stderr=fnull()) != 0:
                    raise Exception("Bad Signature") #Todo: verify validity
                else:
                    return True
            ctx = gpgme.Context()
            try:
                signed_file = open(dst, "r")
                signatures = ctx.verify(response, signed_file, None)
                if signatures and signatures[0] and signatures[0].validity \
                    in (gpgme.VALIDITY_FULL, gpgme.VALIDITY_MARGINAL, gpgme.VALIDITY_ULTIMATE):
                    return True
            except gpgme.GpgmeError, ge:
                raise Exception("Bad Signature: %s (%s)" % (str(ge), url))
            raise Exception("Bad Signature (%s)" % (url))
        else:
            return True

    def fetch_patch(self):
        if self.patch_level == "0":
            loginfo("No updates are needed for this kernel")
            return "0"
        path = self._get_cache_path("/")
        if not os.path.exists(path): os.makedirs(path)
        elif os.path.exists(path + PATCH_DONE):
            loginfo("Updates already downloaded")
            return self.patch_level
        loginfo("Downloading updates")
        self.fetch_patch_file(PATCH_BIN, check_signature=True)
        self.fetch_patch_file(PATCH_INFO, check_signature=True)
        self.fetch_kmod()
        self.exctract_blacklist()
        open(path+PATCH_DONE, "wb").close()
        return self.patch_level

    def exctract_blacklist(self):
        buf = open(self._get_cache_path(PATCH_INFO), 'r').read()
        if buf:
            bstart = buf.find(BLACKLIST_START)
            if bstart <> -1:
                bend = buf.find(BLACKLIST_END)
                if bend <> -1:
                    open(self._get_cache_path(BLACKLIST_FILE), 'w').write(buf[bstart+len(BLACKLIST_START):bend])


class S3PatchFetcher(PatchFetcher):
    def __init__(self, hash, patch_level=None):
        PatchFetcher.__init__(self, hash, patch_level)
        url_template = "{protocol}{server}/{bucket}/{prefix}/{hash}/"
        self.server = url_template.format(protocol="https://",
                                          server="s3.amazonaws.com",
                                          bucket=AWS["bucket"],
                                          prefix=AWS["prefix"],
                                          hash=hash)

    def _request(self, url):
        return http_request(self.get_amazon_s3_auth(url), False)

    @retry(urllib2.URLError, tries=4, delay=3, backoff=2, logger=kcarelog)
    def get_latest_patch_level(self):
        url = self.server + PATCH_LATEST
        try:
            response = urllib2.urlopen(self._request(url))
        except urllib2.HTTPError, e:
            if e.code == 404:
                raise UnknownKernelException()
            if e.code == 403:
                ip = e.read()
                register_trial(ip)
                raise e
            else:
                raise e
        self.patch_level = response.read().rstrip('\n')

    def get_amazon_s3_auth(self, amazon_uri):
        try:
            from hashlib import sha1
        except ImportError:
            from sha import sha as sha1
        try:
            from urllib import quote
        except ImportError:
            from urllib.parse import quote
        try:
            from urlparse import urlparse
        except ImportError:
            from urllib.parse import urlparse
        from hmac import new
        from datetime import timedelta
        timestamp = str(int(time.mktime((datetime.utcnow()
                                         + timedelta(120)).timetuple())))
        h = new(AWS["secret_key"],
                "GET\n\n\n{s}\n{aws_uri}".format(
                    s=timestamp,
                    aws_uri=urlparse(amazon_uri).path),
                sha1)
        sgn = quote(h.digest().encode("base64").strip())
        url_template = "{url}?AWSAccessKeyId={acid}&Expires={s}&Signature={sgn}"
        return url_template.format(url=amazon_uri,
                                   acid=AWS["access_key"],
                                   s=timestamp,
                                   sgn=sgn)


def get_kernel_hash():
    try:
        # noinspection PyCompatibility
        from hashlib import sha1
    except ImportError:
        from sha import sha as sha1
    f = open(KERNEL_VERSION_FILE, 'rb')
    try:
        return sha1(f.read()).hexdigest()
    finally:
        f.close()


def factor_patch_fetcher():
    if AWS_USE:
        return S3PatchFetcher
    else:
        return PatchFetcher


def get_latest_patch(update_policy="REMOTE"):
    kernel_hash = get_kernel_hash()
    patch_fetcher = factor_patch_fetcher()
    if update_policy == "REMOTE":
        pf = patch_fetcher(kernel_hash)
    else:
        patch_level = get_cache_latest(kernel_hash)
        if patch_level != -1: # use local cache
            pf = patch_fetcher(kernel_hash, patch_level)
        elif update_policy == "LOCAL": #local only
            return "0" # do not patch
        else:
            pf = patch_fetcher(kernel_hash)
    if loaded_patch_level() == pf.patch_level:
        return "0"
    else:
        return pf.fetch_patch()


def clear_cache(hash, patch_level):
    files = glob.glob(PATCH_CACHE+'/*/*'+PATCH_BIN)
    data = []
    for file in files:
        st = os.stat(file)
        data.append((file, st.st_mtime))
    data.sort(key = lambda tup: tup[1])

    if len(data) > CACHE_ENTRIES:
        data = data[CACHE_ENTRIES:]
        for entry in data:
            path = entry[0][:-len('/kpatch.bin')]
            if not path == PATCH_CACHE + '/'+hash + '/'+patch_level:
                shutil.rmtree(path)
    for dir in glob.glob(PATCH_CACHE+'/*'):
        for path,dirs,files in os.walk(dir):
            if len(dirs) == 0:
                shutil.rmtree(dir)
                break
            else:
                break

def patch_info():
    patch_level=patch_level_info()
    if patch_level == None:
        return
    hash = get_kernel_hash()
    patch_info = open(get_cache_path(hash, patch_level, PATCH_INFO), 'r').read()
    buf = patch_info
    if buf:
        bstart = buf.find(BLACKLIST_START)
        if bstart <> -1:
            bend = buf.find(BLACKLIST_END)
            if bend <> -1:
                patch_info = buf[0:bstart-1]+buf[bend+len(BLACKLIST_END):]

    print patch_info

UNAME_LABEL='uname: '

def is_uname_char(c):
    return str.isalnum(c) or c in '.-_+'

def parse_uname(patch_level):
    hash = get_kernel_hash()
    f = open(get_cache_path(hash, patch_level, PATCH_INFO), 'r')
    try:
        for line in f.readlines():
            if line.startswith(UNAME_LABEL):
                return filter(is_uname_char, line[len(UNAME_LABEL):].strip())
    finally:
        f.close()



def kcare_uname_su():
    patch_level = loaded_patch_level()
    if patch_level == None or patch_level=="0":
        return platform.release()
    return parse_uname(patch_level)

BUILD_TIME_LABEL='kpatch-build-time: '

def is_same_patch(patch_file):
    args = [KPATCH_CTL, 'file-info', patch_file]
    new_patch_info = check_output(args)
    current_patch_info = _patch_info()
    return get_patch_value(new_patch_info, BUILD_TIME_LABEL) == get_patch_value(current_patch_info, BUILD_TIME_LABEL)

def kcare_update_effecitve_version(new_version):
    if os.path.exists(KCARE_UNAME_FILE):
        try:
            f = open(KCARE_UNAME_FILE, "w")
            f.write(new_version)
            f.close()
            return True
        except:
            pass
    return False

def kcare_uname():
    if os.path.exists(KCARE_UNAME_FILE):
        return open(KCARE_UNAME_FILE, 'r').read().strip()
    else:
        return kcare_uname_su()


def kcare_update(force=False, update_policy="REMOTE"):
    patch = get_latest_patch(update_policy)
    if patch != '0':
        hash = get_kernel_hash()
        kcare_load(hash, patch, force)
        clear_cache(hash, patch)
        get_latest_patch()


class FakeSecHead(object):
    def __init__(self, fp):
        self.fp = fp
        self.sechead = '[asection]\n'
    def readline(self):
        if self.sechead:
            try: return self.sechead
            finally: self.sechead = None
        else: return self.fp.readline()


def init_config_settings():
    cp = ConfigParser.ConfigParser()
    try:
        cp.readfp(FakeSecHead(open(CONFIG)))
    except:
        return

    try:
        tmp=cp.get('asection', 'UPDATE_POLICY', '')
        if tmp:
            global UPDATE_POLICY
            UPDATE_POLICY=tmp.upper()
    except:
        pass
    try:
        tmp=cp.get('asection', 'PATCH_METHOD', '')
        if tmp:
            global PATCH_METHOD
            PATCH_METHOD=tmp.upper()
    except:
        pass

    try:
        tmp=cp.get('asection', 'PATCH_SERVER', '')
        if tmp:
            global PATCH_SERVER_URL
            PATCH_SERVER_URL=tmp
    except:
        pass

    try:
        tmp=cp.get('asection', 'AUTO_UPDATE', '1').upper()
        global AUTO_UPDATE
        AUTO_UPDATE = (tmp in ("1", "TRUE", "YES", "Y"))
    except:
        pass

    try:
        tmp=cp.get('asection', 'REGISTRATION_URL', '')
        if tmp:
            global REGISTRATION_API_URL
            REGISTRATION_API_URL = tmp
            if REGISTRATION_API_URL.endswith('/'):
                REGISTRATION_API_URL = REGISTRATION_API_URL[:-1]
    except:
        pass

def kcare_auto_update():
    set_print_level(PRINT_ERROR)
    if AUTO_UPDATE:
        kcare_update()
    else:
        get_latest_patch(UPDATE_POLICY)


def print_error(param):
    print param
    exit(1)


# we need python 2.6 compatibility
def check_output(args):
    return subprocess.Popen(args, stdout=subprocess.PIPE).communicate()[0]

def is_kcare_kmod_loaded(loaded_modules=None):
    if not loaded_modules:
        loaded_modules = get_lsmod_output()
    return 'kcare' in loaded_modules.split()

def get_lsmod_output():
    return check_output(['/sbin/lsmod'])

def is_ksplice_loaded(loaded_modules):
    for module in BLACKLIST_MODULES:
        if module in loaded_modules:
            raise Exception("Detected %s kernel module loaded. Please, unload that module first" % module)


KMOD_VERSION_FILE='/sys/module/kcare/version'

def is_kmod_old(hash):
    if not os.path.exists(KMOD_VERSION_FILE):
        return True
    old_version=open(KMOD_VERSION_FILE,'r').read().strip()
    modinfo=check_output(['/sbin/modinfo',get_kmod_path(hash)])
    new_version=''
    for line in modinfo.split('\n'):
        if line.startswith('version:'):
            new_version = line[len('version:'):].strip()
            break
    if not old_version == new_version:
        return True

def _get_kcare_link():
    return '/lib/modules/'+platform.uname()[2]+'/extra/kcare.ko'

def _load_kmod(hash):
    kcare_link = _get_kcare_link()
    kcare_file = get_kmod_path(hash)
    try:
        shutil.copy(kcare_file, kcare_link)
    except:
        kcare_link = kcare_file
    code = subprocess.call(['/sbin/insmod', kcare_link], stdout=fnull())
    if code <> 0:
        raise Exception("Unable to load kmod (%s %d)" % (get_kmod_path(hash), code))
    subprocess.call(['/sbin/depmod'], stdout=fnull(), stderr=fnull())

def load_kmod(hash, loaded_modules):
    if not is_kcare_kmod_loaded(loaded_modules):
        _load_kmod(hash)
    elif is_kmod_old(hash):
        kcare_unload()
        _load_kmod(hash)

def unload_kmod():
    if is_kcare_kmod_loaded():
        code = subprocess.call(['/sbin/rmmod', 'kcare'], stdout=fnull())
        if code <> 0:
            raise Exception("Unable to unload kmod %d" % (code))
    try:
        os.unlink(_get_kcare_link())
    except:
        pass


def fnull():
    return open(os.devnull, "w")

def kcare_load(hash, patch_level, force = False):
    patch_file = get_cache_path(hash, patch_level, PATCH_BIN)
    blacklist_file = get_cache_path(hash, patch_level, BLACKLIST_FILE)
    loaded_modules = get_lsmod_output()
    save_cache_latest(hash, patch_level)

    load_kmod(hash, loaded_modules)

    is_ksplice_loaded(loaded_modules)
    new_version = patch_level+";"+parse_uname(patch_level)
    if is_same_patch(patch_file):
        if kcare_update_effecitve_version(new_version):
            return

    args = [KPATCH_CTL, 'patch', '-d', new_version]
    if force or get_freezer_blacklist().intersection(loaded_modules.split()) or PATCH_METHOD=='NOFREEZE':
        args.append('-n')
    args.append(patch_file)
    if os.path.exists(blacklist_file):
        args.insert(1, "-b")
        args.insert(2, blacklist_file)
    code = subprocess.call(args, stdout=fnull())
    if code <> 0:
        raise Exception("Unable to apply patch (%s %s %d %s %s, %s)" %
                        (patch_file, patch_level, code, get_distro()[0], platform.release(), PATCH_METHOD))
    loginfo("Patch Level %s applied" % (patch_level))

def kcare_unload():
    if is_kcare_kmod_loaded():
        code = subprocess.call([KPATCH_CTL, 'unpatch'], stdout=fnull())
        #todo exception on error?
        unload_kmod()
    else:
        pass
        #do nothing if kernel module is not loaded
    get_latest_patch()

def kcare_info():
    patch_level=patch_level_info()
    if patch_level == None:
        return ""
    return _patch_info()

def _patch_info():
    return check_output([KPATCH_CTL, 'info'])

DESC_LABEL="kpatch-description: "

def get_patch_value(info, label):
    lines = info.split("\n")
    for line in lines:
        line.strip()
        if line.startswith(label):
            return line[len(label):].strip()

def loaded_patch_level():
    if not is_kcare_kmod_loaded():
        return None
    description = get_patch_value(_patch_info(), DESC_LABEL)
    if description is not None:
        return description.split(';')[0]

LEVEL_PATCH_AVAILABLE="PATCH_AVAILABLE"
LEVEL_UNKNOWN_KERNEL="UNKNOWN_KERNEL"
LEVEL_NO_PATCHES="NO_PATCHES"

def patch_level_info():
    patch_level = loaded_patch_level()
    if patch_level is None:
        try:
            patch_fetcher = factor_patch_fetcher()
            pf = patch_fetcher(get_kernel_hash())
            if pf.patch_level == "0":
                print "This kernel doesn't require any patches"
            else:
                print "No patches applied, but some are available, run kcarectl --update"
        except UnknownKernelException:
            print "Unknown kernel (%s %s), no patches available" % (get_distro()[0], platform.release())
    return patch_level

def check_gpg_bin():
    if not os.path.isfile(GPG_BIN):
        raise Exception("No %s present, please install gnupg" % GPG_BIN)

GPG_OWNER_TRUST='034327E8206469CB296AC14ECCE80D2B8B53D14B:6:\n'
def import_gpg_key(import_key):
    if not os.path.exists(GPG_KEY_DIR):
        os.makedirs(GPG_KEY_DIR)
    os.environ['GNUPGHOME'] = GPG_KEY_DIR
    if gpgme is None:
        check_gpg_bin()
        subprocess.call([GPG_BIN, '--import', import_key], stderr=fnull())
        p = subprocess.Popen([GPG_BIN, '--import-ownertrust'], stdin=subprocess.PIPE, stderr=fnull())\
            .communicate(input=GPG_OWNER_TRUST)
        return
    ctx = gpgme.Context()
    fp = open(os.path.join(GPG_KEY_DIR, 'gpg.conf'), 'wb')
    fp.write('')
    fp.close()
    f = open(import_key, 'r')
    try:
        ctx.import_(f)
    finally:
        f.close()
    k = ctx.get_key(GPG_KEY_ID)
    gpgme.editutil.edit_trust(ctx, k, gpgme.VALIDITY_ULTIMATE)


def rm_serverid():
    os.unlink(SYSTEMID)

def set_serverid(server_id):
    f = open(SYSTEMID, 'wb')
    try:
        f.write("server_id=%s\n" % server_id)
    finally:
        f.close()

def get_serverid():
    cp = ConfigParser.ConfigParser()
    try:
        cp.readfp(FakeSecHead(open(SYSTEMID)))
        return cp.get('asection', 'server_id', '1')
    except IOError:
        return None
        # no config, nothing to do

def parse_plain(response):
    result = {}
    for line in response.split('\n'):
        if line and ':' in line:
            sp = line.split(':', 1)
            result[sp[0]] = sp[1]
    return result

def unregister(silent = False):
    try:
        server_id = get_serverid()
        if server_id is None:
            if not silent:
                print "Error unregistering server: cannot find server id"
            return
        response = urllib2.urlopen(REGISTRATION_API_URL+'/unregister_server.plain?server_id=%s' % server_id)
        res = parse_plain(response.read())
        if res['success'] == 'true':
            rm_serverid()
            if not silent:
                print "Server was unregistered"
        elif not silent:
            print res
            print "Error unregistering server: "+res['message']
    except urllib2.HTTPError, e:
        if not silent:
            print_cln_http_error(e)


def register(key):
    try:
        unregister(True)
    except:
        pass

    try:
        response = urllib2.urlopen(REGISTRATION_API_URL+'/register_server.plain?key=%s' % key)
        res = parse_plain(response.read())
        code = res['code']
        if code == "0":
            set_serverid(res['server_id'])
            print "Server Registered"
            return True
        elif code == "1":
            print "Account Locked"
        elif code == "2":
            print "Invalid Key"
        elif code == "3":
            print "Key limit reached"
        elif code == "4":
            print "IP not allowed"
        else:
            print "Unknown Error"
    except urllib2.HTTPError, e:
        print_cln_http_error(e)
    return False


def main():
    parser = ArgumentParser(description='Manage KernelCare patches for your kernel')
    parser.add_argument("-i", "--info",
                        help="Display information about KernelCare",
                        action="store_true")
    parser.add_argument("-u", "--update",
                        help="Download latest patches, and apply them to current kernel",
                        action="store_true")
    parser.add_argument("--unload",
                        help="Unload patches",
                        action="store_true")
    parser.add_argument("--smart-update",
                        help="Try to patch kernel based on UPDATE POLICY settings",
                        action="store_true")
    parser.add_argument("--auto-update",
                        help="Check if update is needed, and update",
                        action="store_true")
    parser.add_argument("--patch-info",
                       help="Lists applied patched",
                       action="store_true")
    parser.add_argument("--nofreeze",
                        help="don't freeze tasks before patch",
                        action="store_true")
    parser.add_argument("--force",
                        help="[deprecated] when used with update, forces applying the patch even if unable to freeze some threads",
                        action="store_true")
    parser.add_argument("--uname",
                        help="Prints safe kernel version",
                        action="store_true")
    parser.add_argument("--license-info",
                        help="Output current license info",
                        action="store_true")
    parser.add_argument("--import-key",
                        help="Import gpg key", metavar='PATH')
    parser.add_argument("--register",
                        help="Register using KernelCare Key",
                        metavar='KEY')
    parser.add_argument("--unregister",
                        help="Unregister from KernelCare for Key based servers",
                        action="store_true")
    parser.add_argument("--test",
                        help="Try test builds instead of production builds",
                        action="store_true")
    parser.add_argument("--test-s3",
                        help="Try test builds from Amazon S3 instead of patch server",
                        action="store_true")
    parser.add_argument("--aws-access-key",
                        help="AWS Access key",
                        metavar='KEY')
    parser.add_argument("--aws-secret-key",
                        help="AWS Secret key",
                        metavar='KEY')
    parser.add_argument("--aws-region",
                        help="AWS Region",
                        metavar='REGION')
    parser.add_argument("--aws-bucket",
                        help="Amazon S3 bucket name",
                        metavar='BUCKET')
    parser.add_argument("--aws-prefix",
                        help="Prefix for navigation in S3 bucket",
                        metavar='PREFIX')
    parser.add_argument("--version",
                        help="Print KernelCare version",
                        action="store_true")

    args = parser.parse_args()

    init_config_settings()

    if args.unregister:
        unregister()
    if args.register:
        register(args.register)
    if args.license_info:
        license_info()
    if args.test:
        global TEST_PREFIX
        TEST_PREFIX='/test'
    if args.test_s3:
        global AWS_USE
        global AWS
        AWS_USE = True
        if args.aws_access_key:
            AWS["access_key"] = args.aws_access_key
        if args.aws_secret_key:
            AWS["secret_key"] = args.aws_secret_key
        if args.aws_region:
            AWS["region"] = args.aws_region
        if args.aws_bucket:
            AWS["bucket"] = args.aws_bucket
        if args.aws_prefix:
            AWS["prefix"] = args.aws_prefix
    if args.version:
        print VERSION
    if args.info:
        print kcare_info()
    if args.smart_update:
        kcare_update(args.force or args.nofreeze, UPDATE_POLICY)
    if args.update:
        kcare_update(args.force or args.nofreeze)
        print "Kernel is safe"
    if args.uname:
        print kcare_uname()
    if args.unload:
        kcare_unload()
        print "KernelCare protection disabled, kernel might not be safe"
    if args.auto_update:
        kcare_auto_update()
    if args.patch_info:
        patch_info()
    if args.import_key:
        import_gpg_key(args.import_key)





########Argparse###############

############################ Author: Steven J. Bethard <steven.bethard@gmail.com>.
# Author: Steven J. Bethard <steven.bethard@gmail.com>.

"""Command-line parsing library

This module is an optparse-inspired command-line parsing library that:

    - handles both optional and positional arguments
    - produces highly informative usage messages
    - supports parsers that dispatch to sub-parsers

The following is a simple usage example that sums integers from the
command-line and writes the result to a file::

    parser = argparse.ArgumentParser(
        description='sum the integers at the command line')
    parser.add_argument(
        'integers', metavar='int', nargs='+', type=int,
        help='an integer to be summed')
    parser.add_argument(
        '--log', default=sys.stdout, type=argparse.FileType('w'),
        help='the file where the sum should be written')
    args = parser.parse_args()
    args.log.write('%s' % sum(args.integers))
    args.log.close()

The module contains the following public classes:

    - ArgumentParser -- The main entry point for command-line parsing. As the
        example above shows, the add_argument() method is used to populate
        the parser with actions for optional and positional arguments. Then
        the parse_args() method is invoked to convert the args at the
        command-line into an object with attributes.

    - ArgumentError -- The exception raised by ArgumentParser objects when
        there are errors with the parser's actions. Errors raised while
        parsing the command-line are caught by ArgumentParser and emitted
        as command-line messages.

    - FileType -- A factory for defining types of files to be created. As the
        example above shows, instances of FileType are typically passed as
        the type= argument of add_argument() calls.

    - Action -- The base class for parser actions. Typically actions are
        selected by passing strings like 'store_true' or 'append_const' to
        the action= argument of add_argument(). However, for greater
        customization of ArgumentParser actions, subclasses of Action may
        be defined and passed as the action= argument.

    - HelpFormatter, RawDescriptionHelpFormatter, RawTextHelpFormatter,
        ArgumentDefaultsHelpFormatter -- Formatter classes which
        may be passed as the formatter_class= argument to the
        ArgumentParser constructor. HelpFormatter is the default,
        RawDescriptionHelpFormatter and RawTextHelpFormatter tell the parser
        not to change the formatting for help text, and
        ArgumentDefaultsHelpFormatter adds information about argument defaults
        to the help.

All other classes in this module are considered implementation details.
(Also note that HelpFormatter and RawDescriptionHelpFormatter are only
considered public as object names -- the API of the formatter objects is
still considered an implementation detail.)
"""

__version__ = '1.2.1'
__all__ = [
    'ArgumentParser',
    'ArgumentError',
    'ArgumentTypeError',
    'FileType',
    'HelpFormatter',
    'ArgumentDefaultsHelpFormatter',
    'RawDescriptionHelpFormatter',
    'RawTextHelpFormatter',
    'Namespace',
    'Action',
    'ONE_OR_MORE',
    'OPTIONAL',
    'PARSER',
    'REMAINDER',
    'SUPPRESS',
    'ZERO_OR_MORE',
]


import copy as _copy
import os as _os
import re as _re
import sys as _sys
import textwrap as _textwrap

from gettext import gettext as _

try:
    set
except NameError:
    # for python < 2.4 compatibility (sets module is there since 2.3):
    from sets import Set as set

try:
    basestring
except NameError:
    basestring = str

try:
    sorted
except NameError:
    # for python < 2.4 compatibility:
    def sorted(iterable, reverse=False):
        result = list(iterable)
        result.sort()
        if reverse:
            result.reverse()
        return result


def _callable(obj):
    return hasattr(obj, '__call__') or hasattr(obj, '__bases__')


SUPPRESS = '==SUPPRESS=='

OPTIONAL = '?'
ZERO_OR_MORE = '*'
ONE_OR_MORE = '+'
PARSER = 'A...'
REMAINDER = '...'
_UNRECOGNIZED_ARGS_ATTR = '_unrecognized_args'

# =============================
# Utility functions and classes
# =============================

class _AttributeHolder(object):
    """Abstract base class that provides __repr__.

    The __repr__ method returns a string in the format::
        ClassName(attr=name, attr=name, ...)
    The attributes are determined either by a class-level attribute,
    '_kwarg_names', or by inspecting the instance __dict__.
    """

    def __repr__(self):
        type_name = type(self).__name__
        arg_strings = []
        for arg in self._get_args():
            arg_strings.append(repr(arg))
        for name, value in self._get_kwargs():
            arg_strings.append('%s=%r' % (name, value))
        return '%s(%s)' % (type_name, ', '.join(arg_strings))

    def _get_kwargs(self):
        return sorted(self.__dict__.items())

    def _get_args(self):
        return []


def _ensure_value(namespace, name, value):
    if getattr(namespace, name, None) is None:
        setattr(namespace, name, value)
    return getattr(namespace, name)


# ===============
# Formatting Help
# ===============

class HelpFormatter(object):
    """Formatter for generating usage messages and argument help strings.

    Only the name of this class is considered a public API. All the methods
    provided by the class are considered an implementation detail.
    """

    def __init__(self,
                 prog,
                 indent_increment=2,
                 max_help_position=24,
                 width=None):

        # default setting for width
        if width is None:
            try:
                width = int(_os.environ['COLUMNS'])
            except (KeyError, ValueError):
                width = 80
            width -= 2

        self._prog = prog
        self._indent_increment = indent_increment
        self._max_help_position = max_help_position
        self._width = width

        self._current_indent = 0
        self._level = 0
        self._action_max_length = 0

        self._root_section = self._Section(self, None)
        self._current_section = self._root_section

        self._whitespace_matcher = _re.compile(r'\s+')
        self._long_break_matcher = _re.compile(r'\n\n\n+')

    # ===============================
    # Section and indentation methods
    # ===============================
    def _indent(self):
        self._current_indent += self._indent_increment
        self._level += 1

    def _dedent(self):
        self._current_indent -= self._indent_increment
        assert self._current_indent >= 0, 'Indent decreased below 0.'
        self._level -= 1

    class _Section(object):

        def __init__(self, formatter, parent, heading=None):
            self.formatter = formatter
            self.parent = parent
            self.heading = heading
            self.items = []

        def format_help(self):
            # format the indented section
            if self.parent is not None:
                self.formatter._indent()
            join = self.formatter._join_parts
            for func, args in self.items:
                func(*args)
            item_help = join([func(*args) for func, args in self.items])
            if self.parent is not None:
                self.formatter._dedent()

            # return nothing if the section was empty
            if not item_help:
                return ''

            # add the heading if the section was non-empty
            if self.heading is not SUPPRESS and self.heading is not None:
                current_indent = self.formatter._current_indent
                heading = '%*s%s:\n' % (current_indent, '', self.heading)
            else:
                heading = ''

            # join the section-initial newline, the heading and the help
            return join(['\n', heading, item_help, '\n'])

    def _add_item(self, func, args):
        self._current_section.items.append((func, args))

    # ========================
    # Message building methods
    # ========================
    def start_section(self, heading):
        self._indent()
        section = self._Section(self, self._current_section, heading)
        self._add_item(section.format_help, [])
        self._current_section = section

    def end_section(self):
        self._current_section = self._current_section.parent
        self._dedent()

    def add_text(self, text):
        if text is not SUPPRESS and text is not None:
            self._add_item(self._format_text, [text])

    def add_usage(self, usage, actions, groups, prefix=None):
        if usage is not SUPPRESS:
            args = usage, actions, groups, prefix
            self._add_item(self._format_usage, args)

    def add_argument(self, action):
        if action.help is not SUPPRESS:

            # find all invocations
            get_invocation = self._format_action_invocation
            invocations = [get_invocation(action)]
            for subaction in self._iter_indented_subactions(action):
                invocations.append(get_invocation(subaction))

            # update the maximum item length
            invocation_length = max([len(s) for s in invocations])
            action_length = invocation_length + self._current_indent
            self._action_max_length = max(self._action_max_length,
                                          action_length)

            # add the item to the list
            self._add_item(self._format_action, [action])

    def add_arguments(self, actions):
        for action in actions:
            self.add_argument(action)

    # =======================
    # Help-formatting methods
    # =======================
    def format_help(self):
        help = self._root_section.format_help()
        if help:
            help = self._long_break_matcher.sub('\n\n', help)
            help = help.strip('\n') + '\n'
        return help

    def _join_parts(self, part_strings):
        return ''.join([part
                        for part in part_strings
                        if part and part is not SUPPRESS])

    def _format_usage(self, usage, actions, groups, prefix):
        if prefix is None:
            prefix = _('usage: ')

        # if usage is specified, use that
        if usage is not None:
            usage = usage % dict(prog=self._prog)

        # if no optionals or positionals are available, usage is just prog
        elif usage is None and not actions:
            usage = '%(prog)s' % dict(prog=self._prog)

        # if optionals and positionals are available, calculate usage
        elif usage is None:
            prog = '%(prog)s' % dict(prog=self._prog)

            # split optionals from positionals
            optionals = []
            positionals = []
            for action in actions:
                if action.option_strings:
                    optionals.append(action)
                else:
                    positionals.append(action)

            # build full usage string
            format = self._format_actions_usage
            action_usage = format(optionals + positionals, groups)
            usage = ' '.join([s for s in [prog, action_usage] if s])

            # wrap the usage parts if it's too long
            text_width = self._width - self._current_indent
            if len(prefix) + len(usage) > text_width:

                # break usage into wrappable parts
                part_regexp = r'\(.*?\)+|\[.*?\]+|\S+'
                opt_usage = format(optionals, groups)
                pos_usage = format(positionals, groups)
                opt_parts = _re.findall(part_regexp, opt_usage)
                pos_parts = _re.findall(part_regexp, pos_usage)
                assert ' '.join(opt_parts) == opt_usage
                assert ' '.join(pos_parts) == pos_usage

                # helper for wrapping lines
                def get_lines(parts, indent, prefix=None):
                    lines = []
                    line = []
                    if prefix is not None:
                        line_len = len(prefix) - 1
                    else:
                        line_len = len(indent) - 1
                    for part in parts:
                        if line_len + 1 + len(part) > text_width:
                            lines.append(indent + ' '.join(line))
                            line = []
                            line_len = len(indent) - 1
                        line.append(part)
                        line_len += len(part) + 1
                    if line:
                        lines.append(indent + ' '.join(line))
                    if prefix is not None:
                        lines[0] = lines[0][len(indent):]
                    return lines

                # if prog is short, follow it with optionals or positionals
                if len(prefix) + len(prog) <= 0.75 * text_width:
                    indent = ' ' * (len(prefix) + len(prog) + 1)
                    if opt_parts:
                        lines = get_lines([prog] + opt_parts, indent, prefix)
                        lines.extend(get_lines(pos_parts, indent))
                    elif pos_parts:
                        lines = get_lines([prog] + pos_parts, indent, prefix)
                    else:
                        lines = [prog]

                # if prog is long, put it on its own line
                else:
                    indent = ' ' * len(prefix)
                    parts = opt_parts + pos_parts
                    lines = get_lines(parts, indent)
                    if len(lines) > 1:
                        lines = []
                        lines.extend(get_lines(opt_parts, indent))
                        lines.extend(get_lines(pos_parts, indent))
                    lines = [prog] + lines

                # join lines into usage
                usage = '\n'.join(lines)

        # prefix with 'usage:'
        return '%s%s\n\n' % (prefix, usage)

    def _format_actions_usage(self, actions, groups):
        # find group indices and identify actions in groups
        group_actions = set()
        inserts = {}
        for group in groups:
            try:
                start = actions.index(group._group_actions[0])
            except ValueError:
                continue
            else:
                end = start + len(group._group_actions)
                if actions[start:end] == group._group_actions:
                    for action in group._group_actions:
                        group_actions.add(action)
                    if not group.required:
                        if start in inserts:
                            inserts[start] += ' ['
                        else:
                            inserts[start] = '['
                        inserts[end] = ']'
                    else:
                        if start in inserts:
                            inserts[start] += ' ('
                        else:
                            inserts[start] = '('
                        inserts[end] = ')'
                    for i in range(start + 1, end):
                        inserts[i] = '|'

        # collect all actions format strings
        parts = []
        for i, action in enumerate(actions):

            # suppressed arguments are marked with None
            # remove | separators for suppressed arguments
            if action.help is SUPPRESS:
                parts.append(None)
                if inserts.get(i) == '|':
                    inserts.pop(i)
                elif inserts.get(i + 1) == '|':
                    inserts.pop(i + 1)

            # produce all arg strings
            elif not action.option_strings:
                part = self._format_args(action, action.dest)

                # if it's in a group, strip the outer []
                if action in group_actions:
                    if part[0] == '[' and part[-1] == ']':
                        part = part[1:-1]

                # add the action string to the list
                parts.append(part)

            # produce the first way to invoke the option in brackets
            else:
                option_string = action.option_strings[0]

                # if the Optional doesn't take a value, format is:
                #    -s or --long
                if action.nargs == 0:
                    part = '%s' % option_string

                # if the Optional takes a value, format is:
                #    -s ARGS or --long ARGS
                else:
                    default = action.dest.upper()
                    args_string = self._format_args(action, default)
                    part = '%s %s' % (option_string, args_string)

                # make it look optional if it's not required or in a group
                if not action.required and action not in group_actions:
                    part = '[%s]' % part

                # add the action string to the list
                parts.append(part)

        # insert things at the necessary indices
        for i in sorted(inserts, reverse=True):
            parts[i:i] = [inserts[i]]

        # join all the action items with spaces
        text = ' '.join([item for item in parts if item is not None])

        # clean up separators for mutually exclusive groups
        open = r'[\[(]'
        close = r'[\])]'
        text = _re.sub(r'(%s) ' % open, r'\1', text)
        text = _re.sub(r' (%s)' % close, r'\1', text)
        text = _re.sub(r'%s *%s' % (open, close), r'', text)
        text = _re.sub(r'\(([^|]*)\)', r'\1', text)
        text = text.strip()

        # return the text
        return text

    def _format_text(self, text):
        if '%(prog)' in text:
            text = text % dict(prog=self._prog)
        text_width = self._width - self._current_indent
        indent = ' ' * self._current_indent
        return self._fill_text(text, text_width, indent) + '\n\n'

    def _format_action(self, action):
        # determine the required width and the entry label
        help_position = min(self._action_max_length + 2,
                            self._max_help_position)
        help_width = self._width - help_position
        action_width = help_position - self._current_indent - 2
        action_header = self._format_action_invocation(action)

        # ho nelp; start on same line and add a final newline
        if not action.help:
            tup = self._current_indent, '', action_header
            action_header = '%*s%s\n' % tup

        # short action name; start on the same line and pad two spaces
        elif len(action_header) <= action_width:
            tup = self._current_indent, '', action_width, action_header
            action_header = '%*s%-*s  ' % tup
            indent_first = 0

        # long action name; start on the next line
        else:
            tup = self._current_indent, '', action_header
            action_header = '%*s%s\n' % tup
            indent_first = help_position

        # collect the pieces of the action help
        parts = [action_header]

        # if there was help for the action, add lines of help text
        if action.help:
            help_text = self._expand_help(action)
            help_lines = self._split_lines(help_text, help_width)
            parts.append('%*s%s\n' % (indent_first, '', help_lines[0]))
            for line in help_lines[1:]:
                parts.append('%*s%s\n' % (help_position, '', line))

        # or add a newline if the description doesn't end with one
        elif not action_header.endswith('\n'):
            parts.append('\n')

        # if there are any sub-actions, add their help as well
        for subaction in self._iter_indented_subactions(action):
            parts.append(self._format_action(subaction))

        # return a single string
        return self._join_parts(parts)

    def _format_action_invocation(self, action):
        if not action.option_strings:
            metavar, = self._metavar_formatter(action, action.dest)(1)
            return metavar

        else:
            parts = []

            # if the Optional doesn't take a value, format is:
            #    -s, --long
            if action.nargs == 0:
                parts.extend(action.option_strings)

            # if the Optional takes a value, format is:
            #    -s ARGS, --long ARGS
            else:
                default = action.dest.upper()
                args_string = self._format_args(action, default)
                for option_string in action.option_strings:
                    parts.append('%s %s' % (option_string, args_string))

            return ', '.join(parts)

    def _metavar_formatter(self, action, default_metavar):
        if action.metavar is not None:
            result = action.metavar
        elif action.choices is not None:
            choice_strs = [str(choice) for choice in action.choices]
            result = '{%s}' % ','.join(choice_strs)
        else:
            result = default_metavar

        def format(tuple_size):
            if isinstance(result, tuple):
                return result
            else:
                return (result, ) * tuple_size
        return format

    def _format_args(self, action, default_metavar):
        get_metavar = self._metavar_formatter(action, default_metavar)
        if action.nargs is None:
            result = '%s' % get_metavar(1)
        elif action.nargs == OPTIONAL:
            result = '[%s]' % get_metavar(1)
        elif action.nargs == ZERO_OR_MORE:
            result = '[%s [%s ...]]' % get_metavar(2)
        elif action.nargs == ONE_OR_MORE:
            result = '%s [%s ...]' % get_metavar(2)
        elif action.nargs == REMAINDER:
            result = '...'
        elif action.nargs == PARSER:
            result = '%s ...' % get_metavar(1)
        else:
            formats = ['%s' for _ in range(action.nargs)]
            result = ' '.join(formats) % get_metavar(action.nargs)
        return result

    def _expand_help(self, action):
        params = dict(vars(action), prog=self._prog)
        for name in list(params):
            if params[name] is SUPPRESS:
                del params[name]
        for name in list(params):
            if hasattr(params[name], '__name__'):
                params[name] = params[name].__name__
        if params.get('choices') is not None:
            choices_str = ', '.join([str(c) for c in params['choices']])
            params['choices'] = choices_str
        return self._get_help_string(action) % params

    def _iter_indented_subactions(self, action):
        try:
            get_subactions = action._get_subactions
        except AttributeError:
            pass
        else:
            self._indent()
            for subaction in get_subactions():
                yield subaction
            self._dedent()

    def _split_lines(self, text, width):
        text = self._whitespace_matcher.sub(' ', text).strip()
        return _textwrap.wrap(text, width)

    def _fill_text(self, text, width, indent):
        text = self._whitespace_matcher.sub(' ', text).strip()
        return _textwrap.fill(text, width, initial_indent=indent,
                                           subsequent_indent=indent)

    def _get_help_string(self, action):
        return action.help


class RawDescriptionHelpFormatter(HelpFormatter):
    """Help message formatter which retains any formatting in descriptions.

    Only the name of this class is considered a public API. All the methods
    provided by the class are considered an implementation detail.
    """

    def _fill_text(self, text, width, indent):
        return ''.join([indent + line for line in text.splitlines(True)])


class RawTextHelpFormatter(RawDescriptionHelpFormatter):
    """Help message formatter which retains formatting of all help text.

    Only the name of this class is considered a public API. All the methods
    provided by the class are considered an implementation detail.
    """

    def _split_lines(self, text, width):
        return text.splitlines()


class ArgumentDefaultsHelpFormatter(HelpFormatter):
    """Help message formatter which adds default values to argument help.

    Only the name of this class is considered a public API. All the methods
    provided by the class are considered an implementation detail.
    """

    def _get_help_string(self, action):
        help = action.help
        if '%(default)' not in action.help:
            if action.default is not SUPPRESS:
                defaulting_nargs = [OPTIONAL, ZERO_OR_MORE]
                if action.option_strings or action.nargs in defaulting_nargs:
                    help += ' (default: %(default)s)'
        return help


# =====================
# Options and Arguments
# =====================

def _get_action_name(argument):
    if argument is None:
        return None
    elif argument.option_strings:
        return  '/'.join(argument.option_strings)
    elif argument.metavar not in (None, SUPPRESS):
        return argument.metavar
    elif argument.dest not in (None, SUPPRESS):
        return argument.dest
    else:
        return None


class ArgumentError(Exception):
    """An error from creating or using an argument (optional or positional).

    The string value of this exception is the message, augmented with
    information about the argument that caused it.
    """

    def __init__(self, argument, message):
        self.argument_name = _get_action_name(argument)
        self.message = message

    def __str__(self):
        if self.argument_name is None:
            format = '%(message)s'
        else:
            format = 'argument %(argument_name)s: %(message)s'
        return format % dict(message=self.message,
                             argument_name=self.argument_name)


class ArgumentTypeError(Exception):
    """An error from trying to convert a command line string to a type."""
    pass


# ==============
# Action classes
# ==============

class Action(_AttributeHolder):
    """Information about how to convert command line strings to Python objects.

    Action objects are used by an ArgumentParser to represent the information
    needed to parse a single argument from one or more strings from the
    command line. The keyword arguments to the Action constructor are also
    all attributes of Action instances.

    Keyword Arguments:

        - option_strings -- A list of command-line option strings which
            should be associated with this action.

        - dest -- The name of the attribute to hold the created object(s)

        - nargs -- The number of command-line arguments that should be
            consumed. By default, one argument will be consumed and a single
            value will be produced.  Other values include:
                - N (an integer) consumes N arguments (and produces a list)
                - '?' consumes zero or one arguments
                - '*' consumes zero or more arguments (and produces a list)
                - '+' consumes one or more arguments (and produces a list)
            Note that the difference between the default and nargs=1 is that
            with the default, a single value will be produced, while with
            nargs=1, a list containing a single value will be produced.

        - const -- The value to be produced if the option is specified and the
            option uses an action that takes no values.

        - default -- The value to be produced if the option is not specified.

        - type -- The type which the command-line arguments should be converted
            to, should be one of 'string', 'int', 'float', 'complex' or a
            callable object that accepts a single string argument. If None,
            'string' is assumed.

        - choices -- A container of values that should be allowed. If not None,
            after a command-line argument has been converted to the appropriate
            type, an exception will be raised if it is not a member of this
            collection.

        - required -- True if the action must always be specified at the
            command line. This is only meaningful for optional command-line
            arguments.

        - help -- The help string describing the argument.

        - metavar -- The name to be used for the option's argument with the
            help string. If None, the 'dest' value will be used as the name.
    """

    def __init__(self,
                 option_strings,
                 dest,
                 nargs=None,
                 const=None,
                 default=None,
                 type=None,
                 choices=None,
                 required=False,
                 help=None,
                 metavar=None):
        self.option_strings = option_strings
        self.dest = dest
        self.nargs = nargs
        self.const = const
        self.default = default
        self.type = type
        self.choices = choices
        self.required = required
        self.help = help
        self.metavar = metavar

    def _get_kwargs(self):
        names = [
            'option_strings',
            'dest',
            'nargs',
            'const',
            'default',
            'type',
            'choices',
            'help',
            'metavar',
        ]
        return [(name, getattr(self, name)) for name in names]

    def __call__(self, parser, namespace, values, option_string=None):
        raise NotImplementedError(_('.__call__() not defined'))


class _StoreAction(Action):

    def __init__(self,
                 option_strings,
                 dest,
                 nargs=None,
                 const=None,
                 default=None,
                 type=None,
                 choices=None,
                 required=False,
                 help=None,
                 metavar=None):
        if nargs == 0:
            raise ValueError('nargs for store actions must be > 0; if you '
                             'have nothing to store, actions such as store '
                             'true or store const may be more appropriate')
        if const is not None and nargs != OPTIONAL:
            raise ValueError('nargs must be %r to supply const' % OPTIONAL)
        super(_StoreAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            nargs=nargs,
            const=const,
            default=default,
            type=type,
            choices=choices,
            required=required,
            help=help,
            metavar=metavar)

    def __call__(self, parser, namespace, values, option_string=None):
        setattr(namespace, self.dest, values)


class _StoreConstAction(Action):

    def __init__(self,
                 option_strings,
                 dest,
                 const,
                 default=None,
                 required=False,
                 help=None,
                 metavar=None):
        super(_StoreConstAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            nargs=0,
            const=const,
            default=default,
            required=required,
            help=help)

    def __call__(self, parser, namespace, values, option_string=None):
        setattr(namespace, self.dest, self.const)


class _StoreTrueAction(_StoreConstAction):

    def __init__(self,
                 option_strings,
                 dest,
                 default=False,
                 required=False,
                 help=None):
        super(_StoreTrueAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            const=True,
            default=default,
            required=required,
            help=help)


class _StoreFalseAction(_StoreConstAction):

    def __init__(self,
                 option_strings,
                 dest,
                 default=True,
                 required=False,
                 help=None):
        super(_StoreFalseAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            const=False,
            default=default,
            required=required,
            help=help)


class _AppendAction(Action):

    def __init__(self,
                 option_strings,
                 dest,
                 nargs=None,
                 const=None,
                 default=None,
                 type=None,
                 choices=None,
                 required=False,
                 help=None,
                 metavar=None):
        if nargs == 0:
            raise ValueError('nargs for append actions must be > 0; if arg '
                             'strings are not supplying the value to append, '
                             'the append const action may be more appropriate')
        if const is not None and nargs != OPTIONAL:
            raise ValueError('nargs must be %r to supply const' % OPTIONAL)
        super(_AppendAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            nargs=nargs,
            const=const,
            default=default,
            type=type,
            choices=choices,
            required=required,
            help=help,
            metavar=metavar)

    def __call__(self, parser, namespace, values, option_string=None):
        items = _copy.copy(_ensure_value(namespace, self.dest, []))
        items.append(values)
        setattr(namespace, self.dest, items)


class _AppendConstAction(Action):

    def __init__(self,
                 option_strings,
                 dest,
                 const,
                 default=None,
                 required=False,
                 help=None,
                 metavar=None):
        super(_AppendConstAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            nargs=0,
            const=const,
            default=default,
            required=required,
            help=help,
            metavar=metavar)

    def __call__(self, parser, namespace, values, option_string=None):
        items = _copy.copy(_ensure_value(namespace, self.dest, []))
        items.append(self.const)
        setattr(namespace, self.dest, items)


class _CountAction(Action):

    def __init__(self,
                 option_strings,
                 dest,
                 default=None,
                 required=False,
                 help=None):
        super(_CountAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            nargs=0,
            default=default,
            required=required,
            help=help)

    def __call__(self, parser, namespace, values, option_string=None):
        new_count = _ensure_value(namespace, self.dest, 0) + 1
        setattr(namespace, self.dest, new_count)


class _HelpAction(Action):

    def __init__(self,
                 option_strings,
                 dest=SUPPRESS,
                 default=SUPPRESS,
                 help=None):
        super(_HelpAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            default=default,
            nargs=0,
            help=help)

    def __call__(self, parser, namespace, values, option_string=None):
        parser.print_help()
        parser.exit()


class _VersionAction(Action):

    def __init__(self,
                 option_strings,
                 version=None,
                 dest=SUPPRESS,
                 default=SUPPRESS,
                 help="show program's version number and exit"):
        super(_VersionAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            default=default,
            nargs=0,
            help=help)
        self.version = version

    def __call__(self, parser, namespace, values, option_string=None):
        version = self.version
        if version is None:
            version = parser.version
        formatter = parser._get_formatter()
        formatter.add_text(version)
        parser.exit(message=formatter.format_help())


class _SubParsersAction(Action):

    class _ChoicesPseudoAction(Action):

        def __init__(self, name, help):
            sup = super(_SubParsersAction._ChoicesPseudoAction, self)
            sup.__init__(option_strings=[], dest=name, help=help)

    def __init__(self,
                 option_strings,
                 prog,
                 parser_class,
                 dest=SUPPRESS,
                 help=None,
                 metavar=None):

        self._prog_prefix = prog
        self._parser_class = parser_class
        self._name_parser_map = {}
        self._choices_actions = []

        super(_SubParsersAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            nargs=PARSER,
            choices=self._name_parser_map,
            help=help,
            metavar=metavar)

    def add_parser(self, name, **kwargs):
        # set prog from the existing prefix
        if kwargs.get('prog') is None:
            kwargs['prog'] = '%s %s' % (self._prog_prefix, name)

        # create a pseudo-action to hold the choice help
        if 'help' in kwargs:
            help = kwargs.pop('help')
            choice_action = self._ChoicesPseudoAction(name, help)
            self._choices_actions.append(choice_action)

        # create the parser and add it to the map
        parser = self._parser_class(**kwargs)
        self._name_parser_map[name] = parser
        return parser

    def _get_subactions(self):
        return self._choices_actions

    def __call__(self, parser, namespace, values, option_string=None):
        parser_name = values[0]
        arg_strings = values[1:]

        # set the parser name if requested
        if self.dest is not SUPPRESS:
            setattr(namespace, self.dest, parser_name)

        # select the parser
        try:
            parser = self._name_parser_map[parser_name]
        except KeyError:
            tup = parser_name, ', '.join(self._name_parser_map)
            msg = _('unknown parser %r (choices: %s)' % tup)
            raise ArgumentError(self, msg)

        # parse all the remaining options into the namespace
        # store any unrecognized options on the object, so that the top
        # level parser can decide what to do with them
        namespace, arg_strings = parser.parse_known_args(arg_strings, namespace)
        if arg_strings:
            vars(namespace).setdefault(_UNRECOGNIZED_ARGS_ATTR, [])
            getattr(namespace, _UNRECOGNIZED_ARGS_ATTR).extend(arg_strings)


# ==============
# Type classes
# ==============

class FileType(object):
    """Factory for creating file object types

    Instances of FileType are typically passed as type= arguments to the
    ArgumentParser add_argument() method.

    Keyword Arguments:
        - mode -- A string indicating how the file is to be opened. Accepts the
            same values as the builtin open() function.
        - bufsize -- The file's desired buffer size. Accepts the same values as
            the builtin open() function.
    """

    def __init__(self, mode='r', bufsize=None):
        self._mode = mode
        self._bufsize = bufsize

    def __call__(self, string):
        # the special argument "-" means sys.std{in,out}
        if string == '-':
            if 'r' in self._mode:
                return _sys.stdin
            elif 'w' in self._mode:
                return _sys.stdout
            else:
                msg = _('argument "-" with mode %r' % self._mode)
                raise ValueError(msg)

        # all other arguments are used as file names
        if self._bufsize:
            return open(string, self._mode, self._bufsize)
        else:
            return open(string, self._mode)

    def __repr__(self):
        args = [self._mode, self._bufsize]
        args_str = ', '.join([repr(arg) for arg in args if arg is not None])
        return '%s(%s)' % (type(self).__name__, args_str)

# ===========================
# Optional and Positional Parsing
# ===========================

class Namespace(_AttributeHolder):
    """Simple object for storing attributes.

    Implements equality by attribute names and values, and provides a simple
    string representation.
    """

    def __init__(self, **kwargs):
        for name in kwargs:
            setattr(self, name, kwargs[name])

    __hash__ = None

    def __eq__(self, other):
        return vars(self) == vars(other)

    def __ne__(self, other):
        return not (self == other)

    def __contains__(self, key):
        return key in self.__dict__


class _ActionsContainer(object):

    def __init__(self,
                 description,
                 prefix_chars,
                 argument_default,
                 conflict_handler):
        super(_ActionsContainer, self).__init__()

        self.description = description
        self.argument_default = argument_default
        self.prefix_chars = prefix_chars
        self.conflict_handler = conflict_handler

        # set up registries
        self._registries = {}

        # register actions
        self.register('action', None, _StoreAction)
        self.register('action', 'store', _StoreAction)
        self.register('action', 'store_const', _StoreConstAction)
        self.register('action', 'store_true', _StoreTrueAction)
        self.register('action', 'store_false', _StoreFalseAction)
        self.register('action', 'append', _AppendAction)
        self.register('action', 'append_const', _AppendConstAction)
        self.register('action', 'count', _CountAction)
        self.register('action', 'help', _HelpAction)
        self.register('action', 'version', _VersionAction)
        self.register('action', 'parsers', _SubParsersAction)

        # raise an exception if the conflict handler is invalid
        self._get_handler()

        # action storage
        self._actions = []
        self._option_string_actions = {}

        # groups
        self._action_groups = []
        self._mutually_exclusive_groups = []

        # defaults storage
        self._defaults = {}

        # determines whether an "option" looks like a negative number
        self._negative_number_matcher = _re.compile(r'^-\d+$|^-\d*\.\d+$')

        # whether or not there are any optionals that look like negative
        # numbers -- uses a list so it can be shared and edited
        self._has_negative_number_optionals = []

    # ====================
    # Registration methods
    # ====================
    def register(self, registry_name, value, object):
        registry = self._registries.setdefault(registry_name, {})
        registry[value] = object

    def _registry_get(self, registry_name, value, default=None):
        return self._registries[registry_name].get(value, default)

    # ==================================
    # Namespace default accessor methods
    # ==================================
    def set_defaults(self, **kwargs):
        self._defaults.update(kwargs)

        # if these defaults match any existing arguments, replace
        # the previous default on the object with the new one
        for action in self._actions:
            if action.dest in kwargs:
                action.default = kwargs[action.dest]

    def get_default(self, dest):
        for action in self._actions:
            if action.dest == dest and action.default is not None:
                return action.default
        return self._defaults.get(dest, None)


    # =======================
    # Adding argument actions
    # =======================
    def add_argument(self, *args, **kwargs):
        """
        add_argument(dest, ..., name=value, ...)
        add_argument(option_string, option_string, ..., name=value, ...)
        """

        # if no positional args are supplied or only one is supplied and
        # it doesn't look like an option string, parse a positional
        # argument
        chars = self.prefix_chars
        if not args or len(args) == 1 and args[0][0] not in chars:
            if args and 'dest' in kwargs:
                raise ValueError('dest supplied twice for positional argument')
            kwargs = self._get_positional_kwargs(*args, **kwargs)

        # otherwise, we're adding an optional argument
        else:
            kwargs = self._get_optional_kwargs(*args, **kwargs)

        # if no default was supplied, use the parser-level default
        if 'default' not in kwargs:
            dest = kwargs['dest']
            if dest in self._defaults:
                kwargs['default'] = self._defaults[dest]
            elif self.argument_default is not None:
                kwargs['default'] = self.argument_default

        # create the action object, and add it to the parser
        action_class = self._pop_action_class(kwargs)
        if not _callable(action_class):
            raise ValueError('unknown action "%s"' % action_class)
        action = action_class(**kwargs)

        # raise an error if the action type is not callable
        type_func = self._registry_get('type', action.type, action.type)
        if not _callable(type_func):
            raise ValueError('%r is not callable' % type_func)

        return self._add_action(action)

    def add_argument_group(self, *args, **kwargs):
        group = _ArgumentGroup(self, *args, **kwargs)
        self._action_groups.append(group)
        return group

    def add_mutually_exclusive_group(self, **kwargs):
        group = _MutuallyExclusiveGroup(self, **kwargs)
        self._mutually_exclusive_groups.append(group)
        return group

    def _add_action(self, action):
        # resolve any conflicts
        self._check_conflict(action)

        # add to actions list
        self._actions.append(action)
        action.container = self

        # index the action by any option strings it has
        for option_string in action.option_strings:
            self._option_string_actions[option_string] = action

        # set the flag if any option strings look like negative numbers
        for option_string in action.option_strings:
            if self._negative_number_matcher.match(option_string):
                if not self._has_negative_number_optionals:
                    self._has_negative_number_optionals.append(True)

        # return the created action
        return action

    def _remove_action(self, action):
        self._actions.remove(action)

    def _add_container_actions(self, container):
        # collect groups by titles
        title_group_map = {}
        for group in self._action_groups:
            if group.title in title_group_map:
                msg = _('cannot merge actions - two groups are named %r')
                raise ValueError(msg % (group.title))
            title_group_map[group.title] = group

        # map each action to its group
        group_map = {}
        for group in container._action_groups:

            # if a group with the title exists, use that, otherwise
            # create a new group matching the container's group
            if group.title not in title_group_map:
                title_group_map[group.title] = self.add_argument_group(
                    title=group.title,
                    description=group.description,
                    conflict_handler=group.conflict_handler)

            # map the actions to their new group
            for action in group._group_actions:
                group_map[action] = title_group_map[group.title]

        # add container's mutually exclusive groups
        # NOTE: if add_mutually_exclusive_group ever gains title= and
        # description= then this code will need to be expanded as above
        for group in container._mutually_exclusive_groups:
            mutex_group = self.add_mutually_exclusive_group(
                required=group.required)

            # map the actions to their new mutex group
            for action in group._group_actions:
                group_map[action] = mutex_group

        # add all actions to this container or their group
        for action in container._actions:
            group_map.get(action, self)._add_action(action)

    def _get_positional_kwargs(self, dest, **kwargs):
        # make sure required is not specified
        if 'required' in kwargs:
            msg = _("'required' is an invalid argument for positionals")
            raise TypeError(msg)

        # mark positional arguments as required if at least one is
        # always required
        if kwargs.get('nargs') not in [OPTIONAL, ZERO_OR_MORE]:
            kwargs['required'] = True
        if kwargs.get('nargs') == ZERO_OR_MORE and 'default' not in kwargs:
            kwargs['required'] = True

        # return the keyword arguments with no option strings
        return dict(kwargs, dest=dest, option_strings=[])

    def _get_optional_kwargs(self, *args, **kwargs):
        # determine short and long option strings
        option_strings = []
        long_option_strings = []
        for option_string in args:
            # error on strings that don't start with an appropriate prefix
            if not option_string[0] in self.prefix_chars:
                msg = _('invalid option string %r: '
                        'must start with a character %r')
                tup = option_string, self.prefix_chars
                raise ValueError(msg % tup)

            # strings starting with two prefix characters are long options
            option_strings.append(option_string)
            if option_string[0] in self.prefix_chars:
                if len(option_string) > 1:
                    if option_string[1] in self.prefix_chars:
                        long_option_strings.append(option_string)

        # infer destination, '--foo-bar' -> 'foo_bar' and '-x' -> 'x'
        dest = kwargs.pop('dest', None)
        if dest is None:
            if long_option_strings:
                dest_option_string = long_option_strings[0]
            else:
                dest_option_string = option_strings[0]
            dest = dest_option_string.lstrip(self.prefix_chars)
            if not dest:
                msg = _('dest= is required for options like %r')
                raise ValueError(msg % option_string)
            dest = dest.replace('-', '_')

        # return the updated keyword arguments
        return dict(kwargs, dest=dest, option_strings=option_strings)

    def _pop_action_class(self, kwargs, default=None):
        action = kwargs.pop('action', default)
        return self._registry_get('action', action, action)

    def _get_handler(self):
        # determine function from conflict handler string
        handler_func_name = '_handle_conflict_%s' % self.conflict_handler
        try:
            return getattr(self, handler_func_name)
        except AttributeError:
            msg = _('invalid conflict_resolution value: %r')
            raise ValueError(msg % self.conflict_handler)

    def _check_conflict(self, action):

        # find all options that conflict with this option
        confl_optionals = []
        for option_string in action.option_strings:
            if option_string in self._option_string_actions:
                confl_optional = self._option_string_actions[option_string]
                confl_optionals.append((option_string, confl_optional))

        # resolve any conflicts
        if confl_optionals:
            conflict_handler = self._get_handler()
            conflict_handler(action, confl_optionals)

    def _handle_conflict_error(self, action, conflicting_actions):
        message = _('conflicting option string(s): %s')
        conflict_string = ', '.join([option_string
                                     for option_string, action
                                     in conflicting_actions])
        raise ArgumentError(action, message % conflict_string)

    def _handle_conflict_resolve(self, action, conflicting_actions):

        # remove all conflicting options
        for option_string, action in conflicting_actions:

            # remove the conflicting option
            action.option_strings.remove(option_string)
            self._option_string_actions.pop(option_string, None)

            # if the option now has no option string, remove it from the
            # container holding it
            if not action.option_strings:
                action.container._remove_action(action)


class _ArgumentGroup(_ActionsContainer):

    def __init__(self, container, title=None, description=None, **kwargs):
        # add any missing keyword arguments by checking the container
        update = kwargs.setdefault
        update('conflict_handler', container.conflict_handler)
        update('prefix_chars', container.prefix_chars)
        update('argument_default', container.argument_default)
        super_init = super(_ArgumentGroup, self).__init__
        super_init(description=description, **kwargs)

        # group attributes
        self.title = title
        self._group_actions = []

        # share most attributes with the container
        self._registries = container._registries
        self._actions = container._actions
        self._option_string_actions = container._option_string_actions
        self._defaults = container._defaults
        self._has_negative_number_optionals = \
            container._has_negative_number_optionals

    def _add_action(self, action):
        action = super(_ArgumentGroup, self)._add_action(action)
        self._group_actions.append(action)
        return action

    def _remove_action(self, action):
        super(_ArgumentGroup, self)._remove_action(action)
        self._group_actions.remove(action)


class _MutuallyExclusiveGroup(_ArgumentGroup):

    def __init__(self, container, required=False):
        super(_MutuallyExclusiveGroup, self).__init__(container)
        self.required = required
        self._container = container

    def _add_action(self, action):
        if action.required:
            msg = _('mutually exclusive arguments must be optional')
            raise ValueError(msg)
        action = self._container._add_action(action)
        self._group_actions.append(action)
        return action

    def _remove_action(self, action):
        self._container._remove_action(action)
        self._group_actions.remove(action)


class ArgumentParser(_AttributeHolder, _ActionsContainer):
    """Object for parsing command line strings into Python objects.

    Keyword Arguments:
        - prog -- The name of the program (default: sys.argv[0])
        - usage -- A usage message (default: auto-generated from arguments)
        - description -- A description of what the program does
        - epilog -- Text following the argument descriptions
        - parents -- Parsers whose arguments should be copied into this one
        - formatter_class -- HelpFormatter class for printing help messages
        - prefix_chars -- Characters that prefix optional arguments
        - fromfile_prefix_chars -- Characters that prefix files containing
            additional arguments
        - argument_default -- The default value for all arguments
        - conflict_handler -- String indicating how to handle conflicts
        - add_help -- Add a -h/-help option
    """

    def __init__(self,
                 prog=None,
                 usage=None,
                 description=None,
                 epilog=None,
                 version=None,
                 parents=[],
                 formatter_class=HelpFormatter,
                 prefix_chars='-',
                 fromfile_prefix_chars=None,
                 argument_default=None,
                 conflict_handler='error',
                 add_help=True):

        if version is not None:
            import warnings
            warnings.warn(
                """The "version" argument to ArgumentParser is deprecated. """
                """Please use """
                """"add_argument(..., action='version', version="N", ...)" """
                """instead""", DeprecationWarning)

        superinit = super(ArgumentParser, self).__init__
        superinit(description=description,
                  prefix_chars=prefix_chars,
                  argument_default=argument_default,
                  conflict_handler=conflict_handler)

        # default setting for prog
        if prog is None:
            prog = _os.path.basename(_sys.argv[0])

        self.prog = prog
        self.usage = usage
        self.epilog = epilog
        self.version = version
        self.formatter_class = formatter_class
        self.fromfile_prefix_chars = fromfile_prefix_chars
        self.add_help = add_help

        add_group = self.add_argument_group
        self._positionals = add_group(_('positional arguments'))
        self._optionals = add_group(_('optional arguments'))
        self._subparsers = None

        # register types
        def identity(string):
            return string
        self.register('type', None, identity)

        # add help and version arguments if necessary
        # (using explicit default to override global argument_default)
        if '-' in prefix_chars:
            default_prefix = '-'
        else:
            default_prefix = prefix_chars[0]
        if self.add_help:
            self.add_argument(
                default_prefix+'h', default_prefix*2+'help',
                action='help', default=SUPPRESS,
                help=_('show this help message and exit'))
        if self.version:
            self.add_argument(
                default_prefix+'v', default_prefix*2+'version',
                action='version', default=SUPPRESS,
                version=self.version,
                help=_("show program's version number and exit"))

        # add parent arguments and defaults
        for parent in parents:
            self._add_container_actions(parent)
            try:
                defaults = parent._defaults
            except AttributeError:
                pass
            else:
                self._defaults.update(defaults)

    # =======================
    # Pretty __repr__ methods
    # =======================
    def _get_kwargs(self):
        names = [
            'prog',
            'usage',
            'description',
            'version',
            'formatter_class',
            'conflict_handler',
            'add_help',
        ]
        return [(name, getattr(self, name)) for name in names]

    # ==================================
    # Optional/Positional adding methods
    # ==================================
    def add_subparsers(self, **kwargs):
        if self._subparsers is not None:
            self.error(_('cannot have multiple subparser arguments'))

        # add the parser class to the arguments if it's not present
        kwargs.setdefault('parser_class', type(self))

        if 'title' in kwargs or 'description' in kwargs:
            title = _(kwargs.pop('title', 'subcommands'))
            description = _(kwargs.pop('description', None))
            self._subparsers = self.add_argument_group(title, description)
        else:
            self._subparsers = self._positionals

        # prog defaults to the usage message of this parser, skipping
        # optional arguments and with no "usage:" prefix
        if kwargs.get('prog') is None:
            formatter = self._get_formatter()
            positionals = self._get_positional_actions()
            groups = self._mutually_exclusive_groups
            formatter.add_usage(self.usage, positionals, groups, '')
            kwargs['prog'] = formatter.format_help().strip()

        # create the parsers action and add it to the positionals list
        parsers_class = self._pop_action_class(kwargs, 'parsers')
        action = parsers_class(option_strings=[], **kwargs)
        self._subparsers._add_action(action)

        # return the created parsers action
        return action

    def _add_action(self, action):
        if action.option_strings:
            self._optionals._add_action(action)
        else:
            self._positionals._add_action(action)
        return action

    def _get_optional_actions(self):
        return [action
                for action in self._actions
                if action.option_strings]

    def _get_positional_actions(self):
        return [action
                for action in self._actions
                if not action.option_strings]

    # =====================================
    # Command line argument parsing methods
    # =====================================
    def parse_args(self, args=None, namespace=None):
        args, argv = self.parse_known_args(args, namespace)
        if argv:
            msg = _('unrecognized arguments: %s')
            self.error(msg % ' '.join(argv))
        return args

    def parse_known_args(self, args=None, namespace=None):
        # args default to the system args
        if args is None:
            args = _sys.argv[1:]

        # default Namespace built from parser defaults
        if namespace is None:
            namespace = Namespace()

        # add any action defaults that aren't present
        for action in self._actions:
            if action.dest is not SUPPRESS:
                if not hasattr(namespace, action.dest):
                    if action.default is not SUPPRESS:
                        default = action.default
                        if isinstance(action.default, basestring):
                            default = self._get_value(action, default)
                        setattr(namespace, action.dest, default)

        # add any parser defaults that aren't present
        for dest in self._defaults:
            if not hasattr(namespace, dest):
                setattr(namespace, dest, self._defaults[dest])

        # parse the arguments and exit if there are any errors
        try:
            namespace, args = self._parse_known_args(args, namespace)
            if hasattr(namespace, _UNRECOGNIZED_ARGS_ATTR):
                args.extend(getattr(namespace, _UNRECOGNIZED_ARGS_ATTR))
                delattr(namespace, _UNRECOGNIZED_ARGS_ATTR)
            return namespace, args
        except ArgumentError:
            err = _sys.exc_info()[1]
            self.error(str(err))

    def _parse_known_args(self, arg_strings, namespace):
        # replace arg strings that are file references
        if self.fromfile_prefix_chars is not None:
            arg_strings = self._read_args_from_files(arg_strings)

        # map all mutually exclusive arguments to the other arguments
        # they can't occur with
        action_conflicts = {}
        for mutex_group in self._mutually_exclusive_groups:
            group_actions = mutex_group._group_actions
            for i, mutex_action in enumerate(mutex_group._group_actions):
                conflicts = action_conflicts.setdefault(mutex_action, [])
                conflicts.extend(group_actions[:i])
                conflicts.extend(group_actions[i + 1:])

        # find all option indices, and determine the arg_string_pattern
        # which has an 'O' if there is an option at an index,
        # an 'A' if there is an argument, or a '-' if there is a '--'
        option_string_indices = {}
        arg_string_pattern_parts = []
        arg_strings_iter = iter(arg_strings)
        for i, arg_string in enumerate(arg_strings_iter):

            # all args after -- are non-options
            if arg_string == '--':
                arg_string_pattern_parts.append('-')
                for arg_string in arg_strings_iter:
                    arg_string_pattern_parts.append('A')

            # otherwise, add the arg to the arg strings
            # and note the index if it was an option
            else:
                option_tuple = self._parse_optional(arg_string)
                if option_tuple is None:
                    pattern = 'A'
                else:
                    option_string_indices[i] = option_tuple
                    pattern = 'O'
                arg_string_pattern_parts.append(pattern)

        # join the pieces together to form the pattern
        arg_strings_pattern = ''.join(arg_string_pattern_parts)

        # converts arg strings to the appropriate and then takes the action
        seen_actions = set()
        seen_non_default_actions = set()

        def take_action(action, argument_strings, option_string=None):
            seen_actions.add(action)
            argument_values = self._get_values(action, argument_strings)

            # error if this argument is not allowed with other previously
            # seen arguments, assuming that actions that use the default
            # value don't really count as "present"
            if argument_values is not action.default:
                seen_non_default_actions.add(action)
                for conflict_action in action_conflicts.get(action, []):
                    if conflict_action in seen_non_default_actions:
                        msg = _('not allowed with argument %s')
                        action_name = _get_action_name(conflict_action)
                        raise ArgumentError(action, msg % action_name)

            # take the action if we didn't receive a SUPPRESS value
            # (e.g. from a default)
            if argument_values is not SUPPRESS:
                action(self, namespace, argument_values, option_string)

        # function to convert arg_strings into an optional action
        def consume_optional(start_index):

            # get the optional identified at this index
            option_tuple = option_string_indices[start_index]
            action, option_string, explicit_arg = option_tuple

            # identify additional optionals in the same arg string
            # (e.g. -xyz is the same as -x -y -z if no args are required)
            match_argument = self._match_argument
            action_tuples = []
            while True:

                # if we found no optional action, skip it
                if action is None:
                    extras.append(arg_strings[start_index])
                    return start_index + 1

                # if there is an explicit argument, try to match the
                # optional's string arguments to only this
                if explicit_arg is not None:
                    arg_count = match_argument(action, 'A')

                    # if the action is a single-dash option and takes no
                    # arguments, try to parse more single-dash options out
                    # of the tail of the option string
                    chars = self.prefix_chars
                    if arg_count == 0 and option_string[1] not in chars:
                        action_tuples.append((action, [], option_string))
                        char = option_string[0]
                        option_string = char + explicit_arg[0]
                        new_explicit_arg = explicit_arg[1:] or None
                        optionals_map = self._option_string_actions
                        if option_string in optionals_map:
                            action = optionals_map[option_string]
                            explicit_arg = new_explicit_arg
                        else:
                            msg = _('ignored explicit argument %r')
                            raise ArgumentError(action, msg % explicit_arg)

                    # if the action expect exactly one argument, we've
                    # successfully matched the option; exit the loop
                    elif arg_count == 1:
                        stop = start_index + 1
                        args = [explicit_arg]
                        action_tuples.append((action, args, option_string))
                        break

                    # error if a double-dash option did not use the
                    # explicit argument
                    else:
                        msg = _('ignored explicit argument %r')
                        raise ArgumentError(action, msg % explicit_arg)

                # if there is no explicit argument, try to match the
                # optional's string arguments with the following strings
                # if successful, exit the loop
                else:
                    start = start_index + 1
                    selected_patterns = arg_strings_pattern[start:]
                    arg_count = match_argument(action, selected_patterns)
                    stop = start + arg_count
                    args = arg_strings[start:stop]
                    action_tuples.append((action, args, option_string))
                    break

            # add the Optional to the list and return the index at which
            # the Optional's string args stopped
            assert action_tuples
            for action, args, option_string in action_tuples:
                take_action(action, args, option_string)
            return stop

        # the list of Positionals left to be parsed; this is modified
        # by consume_positionals()
        positionals = self._get_positional_actions()

        # function to convert arg_strings into positional actions
        def consume_positionals(start_index):
            # match as many Positionals as possible
            match_partial = self._match_arguments_partial
            selected_pattern = arg_strings_pattern[start_index:]
            arg_counts = match_partial(positionals, selected_pattern)

            # slice off the appropriate arg strings for each Positional
            # and add the Positional and its args to the list
            for action, arg_count in zip(positionals, arg_counts):
                args = arg_strings[start_index: start_index + arg_count]
                start_index += arg_count
                take_action(action, args)

            # slice off the Positionals that we just parsed and return the
            # index at which the Positionals' string args stopped
            positionals[:] = positionals[len(arg_counts):]
            return start_index

        # consume Positionals and Optionals alternately, until we have
        # passed the last option string
        extras = []
        start_index = 0
        if option_string_indices:
            max_option_string_index = max(option_string_indices)
        else:
            max_option_string_index = -1
        while start_index <= max_option_string_index:

            # consume any Positionals preceding the next option
            next_option_string_index = min([
                index
                for index in option_string_indices
                if index >= start_index])
            if start_index != next_option_string_index:
                positionals_end_index = consume_positionals(start_index)

                # only try to parse the next optional if we didn't consume
                # the option string during the positionals parsing
                if positionals_end_index > start_index:
                    start_index = positionals_end_index
                    continue
                else:
                    start_index = positionals_end_index

            # if we consumed all the positionals we could and we're not
            # at the index of an option string, there were extra arguments
            if start_index not in option_string_indices:
                strings = arg_strings[start_index:next_option_string_index]
                extras.extend(strings)
                start_index = next_option_string_index

            # consume the next optional and any arguments for it
            start_index = consume_optional(start_index)

        # consume any positionals following the last Optional
        stop_index = consume_positionals(start_index)

        # if we didn't consume all the argument strings, there were extras
        extras.extend(arg_strings[stop_index:])

        # if we didn't use all the Positional objects, there were too few
        # arg strings supplied.
        if positionals:
            self.error(_('too few arguments'))

        # make sure all required actions were present
        for action in self._actions:
            if action.required:
                if action not in seen_actions:
                    name = _get_action_name(action)
                    self.error(_('argument %s is required') % name)

        # make sure all required groups had one option present
        for group in self._mutually_exclusive_groups:
            if group.required:
                for action in group._group_actions:
                    if action in seen_non_default_actions:
                        break

                # if no actions were used, report the error
                else:
                    names = [_get_action_name(action)
                             for action in group._group_actions
                             if action.help is not SUPPRESS]
                    msg = _('one of the arguments %s is required')
                    self.error(msg % ' '.join(names))

        # return the updated namespace and the extra arguments
        return namespace, extras

    def _read_args_from_files(self, arg_strings):
        # expand arguments referencing files
        new_arg_strings = []
        for arg_string in arg_strings:

            # for regular arguments, just add them back into the list
            if arg_string[0] not in self.fromfile_prefix_chars:
                new_arg_strings.append(arg_string)

            # # replace arguments referencing files with the file content
            # else:
            #     try:
            #         args_file = open(arg_string[1:])
            #         try:
            #             arg_strings = []
            #             for arg_line in args_file.read().splitlines():
            #                 for arg in self.convert_arg_line_to_args(arg_line):
            #                     arg_strings.append(arg)
            #             arg_strings = self._read_args_from_files(arg_strings)
            #             new_arg_strings.extend(arg_strings)
            #         finally:
            #             args_file.close()
            #     except IOError:
            #         err = _sys.exc_info()[1]
            #         self.error(str(err))

        # return the modified argument list
        return new_arg_strings

    def convert_arg_line_to_args(self, arg_line):
        return [arg_line]

    def _match_argument(self, action, arg_strings_pattern):
        # match the pattern for this action to the arg strings
        nargs_pattern = self._get_nargs_pattern(action)
        match = _re.match(nargs_pattern, arg_strings_pattern)

        # raise an exception if we weren't able to find a match
        if match is None:
            nargs_errors = {
                None: _('expected one argument'),
                OPTIONAL: _('expected at most one argument'),
                ONE_OR_MORE: _('expected at least one argument'),
            }
            default = _('expected %s argument(s)') % action.nargs
            msg = nargs_errors.get(action.nargs, default)
            raise ArgumentError(action, msg)

        # return the number of arguments matched
        return len(match.group(1))

    def _match_arguments_partial(self, actions, arg_strings_pattern):
        # progressively shorten the actions list by slicing off the
        # final actions until we find a match
        result = []
        for i in range(len(actions), 0, -1):
            actions_slice = actions[:i]
            pattern = ''.join([self._get_nargs_pattern(action)
                               for action in actions_slice])
            match = _re.match(pattern, arg_strings_pattern)
            if match is not None:
                result.extend([len(string) for string in match.groups()])
                break

        # return the list of arg string counts
        return result

    def _parse_optional(self, arg_string):
        # if it's an empty string, it was meant to be a positional
        if not arg_string:
            return None

        # if it doesn't start with a prefix, it was meant to be positional
        if not arg_string[0] in self.prefix_chars:
            return None

        # if the option string is present in the parser, return the action
        if arg_string in self._option_string_actions:
            action = self._option_string_actions[arg_string]
            return action, arg_string, None

        # if it's just a single character, it was meant to be positional
        if len(arg_string) == 1:
            return None

        # if the option string before the "=" is present, return the action
        if '=' in arg_string:
            option_string, explicit_arg = arg_string.split('=', 1)
            if option_string in self._option_string_actions:
                action = self._option_string_actions[option_string]
                return action, option_string, explicit_arg

        # search through all possible prefixes of the option string
        # and all actions in the parser for possible interpretations
        option_tuples = self._get_option_tuples(arg_string)

        # if multiple actions match, the option string was ambiguous
        if len(option_tuples) > 1:
            options = ', '.join([option_string
                for action, option_string, explicit_arg in option_tuples])
            tup = arg_string, options
            self.error(_('ambiguous option: %s could match %s') % tup)

        # if exactly one action matched, this segmentation is good,
        # so return the parsed action
        elif len(option_tuples) == 1:
            option_tuple, = option_tuples
            return option_tuple

        # if it was not found as an option, but it looks like a negative
        # number, it was meant to be positional
        # unless there are negative-number-like options
        if self._negative_number_matcher.match(arg_string):
            if not self._has_negative_number_optionals:
                return None

        # if it contains a space, it was meant to be a positional
        if ' ' in arg_string:
            return None

        # it was meant to be an optional but there is no such option
        # in this parser (though it might be a valid option in a subparser)
        return None, arg_string, None

    def _get_option_tuples(self, option_string):
        result = []

        # option strings starting with two prefix characters are only
        # split at the '='
        chars = self.prefix_chars
        if option_string[0] in chars and option_string[1] in chars:
            if '=' in option_string:
                option_prefix, explicit_arg = option_string.split('=', 1)
            else:
                option_prefix = option_string
                explicit_arg = None
            for option_string in self._option_string_actions:
                if option_string.startswith(option_prefix):
                    action = self._option_string_actions[option_string]
                    tup = action, option_string, explicit_arg
                    result.append(tup)

        # single character options can be concatenated with their arguments
        # but multiple character options always have to have their argument
        # separate
        elif option_string[0] in chars and option_string[1] not in chars:
            option_prefix = option_string
            explicit_arg = None
            short_option_prefix = option_string[:2]
            short_explicit_arg = option_string[2:]

            for option_string in self._option_string_actions:
                if option_string == short_option_prefix:
                    action = self._option_string_actions[option_string]
                    tup = action, option_string, short_explicit_arg
                    result.append(tup)
                elif option_string.startswith(option_prefix):
                    action = self._option_string_actions[option_string]
                    tup = action, option_string, explicit_arg
                    result.append(tup)

        # shouldn't ever get here
        else:
            self.error(_('unexpected option string: %s') % option_string)

        # return the collected option tuples
        return result

    def _get_nargs_pattern(self, action):
        # in all examples below, we have to allow for '--' args
        # which are represented as '-' in the pattern
        nargs = action.nargs

        # the default (None) is assumed to be a single argument
        if nargs is None:
            nargs_pattern = '(-*A-*)'

        # allow zero or one arguments
        elif nargs == OPTIONAL:
            nargs_pattern = '(-*A?-*)'

        # allow zero or more arguments
        elif nargs == ZERO_OR_MORE:
            nargs_pattern = '(-*[A-]*)'

        # allow one or more arguments
        elif nargs == ONE_OR_MORE:
            nargs_pattern = '(-*A[A-]*)'

        # allow any number of options or arguments
        elif nargs == REMAINDER:
            nargs_pattern = '([-AO]*)'

        # allow one argument followed by any number of options or arguments
        elif nargs == PARSER:
            nargs_pattern = '(-*A[-AO]*)'

        # all others should be integers
        else:
            nargs_pattern = '(-*%s-*)' % '-*'.join('A' * nargs)

        # if this is an optional action, -- is not allowed
        if action.option_strings:
            nargs_pattern = nargs_pattern.replace('-*', '')
            nargs_pattern = nargs_pattern.replace('-', '')

        # return the pattern
        return nargs_pattern

    # ========================
    # Value conversion methods
    # ========================
    def _get_values(self, action, arg_strings):
        # for everything but PARSER args, strip out '--'
        if action.nargs not in [PARSER, REMAINDER]:
            arg_strings = [s for s in arg_strings if s != '--']

        # optional argument produces a default when not present
        if not arg_strings and action.nargs == OPTIONAL:
            if action.option_strings:
                value = action.const
            else:
                value = action.default
            if isinstance(value, basestring):
                value = self._get_value(action, value)
                self._check_value(action, value)

        # when nargs='*' on a positional, if there were no command-line
        # args, use the default if it is anything other than None
        elif (not arg_strings and action.nargs == ZERO_OR_MORE and
              not action.option_strings):
            if action.default is not None:
                value = action.default
            else:
                value = arg_strings
            self._check_value(action, value)

        # single argument or optional argument produces a single value
        elif len(arg_strings) == 1 and action.nargs in [None, OPTIONAL]:
            arg_string, = arg_strings
            value = self._get_value(action, arg_string)
            self._check_value(action, value)

        # REMAINDER arguments convert all values, checking none
        elif action.nargs == REMAINDER:
            value = [self._get_value(action, v) for v in arg_strings]

        # PARSER arguments convert all values, but check only the first
        elif action.nargs == PARSER:
            value = [self._get_value(action, v) for v in arg_strings]
            self._check_value(action, value[0])

        # all other types of nargs produce a list
        else:
            value = [self._get_value(action, v) for v in arg_strings]
            for v in value:
                self._check_value(action, v)

        # return the converted value
        return value

    def _get_value(self, action, arg_string):
        type_func = self._registry_get('type', action.type, action.type)
        if not _callable(type_func):
            msg = _('%r is not callable')
            raise ArgumentError(action, msg % type_func)

        # convert the value to the appropriate type
        try:
            result = type_func(arg_string)

        # ArgumentTypeErrors indicate errors
        except ArgumentTypeError:
            name = getattr(action.type, '__name__', repr(action.type))
            msg = str(_sys.exc_info()[1])
            raise ArgumentError(action, msg)

        # TypeErrors or ValueErrors also indicate errors
        except (TypeError, ValueError):
            name = getattr(action.type, '__name__', repr(action.type))
            msg = _('invalid %s value: %r')
            raise ArgumentError(action, msg % (name, arg_string))

        # return the converted value
        return result

    def _check_value(self, action, value):
        # converted value must be one of the choices (if specified)
        if action.choices is not None and value not in action.choices:
            tup = value, ', '.join(map(repr, action.choices))
            msg = _('invalid choice: %r (choose from %s)') % tup
            raise ArgumentError(action, msg)

    # =======================
    # Help-formatting methods
    # =======================
    def format_usage(self):
        formatter = self._get_formatter()
        formatter.add_usage(self.usage, self._actions,
                            self._mutually_exclusive_groups)
        return formatter.format_help()

    def format_help(self):
        formatter = self._get_formatter()

        # usage
        formatter.add_usage(self.usage, self._actions,
                            self._mutually_exclusive_groups)

        # description
        formatter.add_text(self.description)

        # positionals, optionals and user-defined groups
        for action_group in self._action_groups:
            formatter.start_section(action_group.title)
            formatter.add_text(action_group.description)
            formatter.add_arguments(action_group._group_actions)
            formatter.end_section()

        # epilog
        formatter.add_text(self.epilog)

        # determine help from format above
        return formatter.format_help()

    def format_version(self):
        import warnings
        warnings.warn(
            'The format_version method is deprecated -- the "version" '
            'argument to ArgumentParser is no longer supported.',
            DeprecationWarning)
        formatter = self._get_formatter()
        formatter.add_text(self.version)
        return formatter.format_help()

    def _get_formatter(self):
        return self.formatter_class(prog=self.prog)

    # =====================
    # Help-printing methods
    # =====================
    def print_usage(self, file=None):
        if file is None:
            file = _sys.stdout
        self._print_message(self.format_usage(), file)

    def print_help(self, file=None):
        if file is None:
            file = _sys.stdout
        self._print_message(self.format_help(), file)

    def print_version(self, file=None):
        import warnings
        warnings.warn(
            'The print_version method is deprecated -- the "version" '
            'argument to ArgumentParser is no longer supported.',
            DeprecationWarning)
        self._print_message(self.format_version(), file)

    def _print_message(self, message, file=None):
        if message:
            if file is None:
                file = _sys.stderr
            file.write(message)

    # ===============
    # Exiting methods
    # ===============
    def exit(self, status=0, message=None):
        if message:
            self._print_message(message, _sys.stderr)
        _sys.exit(status)

    def error(self, message):
        """error(message: string)

        Prints a usage message incorporating the message to stderr and
        exits.

        If you override this in a subclass, it should not return -- it
        should either exit or raise an exception.
        """
        self.print_usage(_sys.stderr)
        self.exit(2, _('%s: error: %s\n') % (self.prog, message))

######## end argparse ###############
if __name__ == "__main__":
    try:
        main()
    except UnknownKernelException, uke:
        logerror(str(uke))
    except Exception, e:
        print str(e)
        kcarelog.exception(e)
