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# aliases.py
# Resolving aliases in CLI arguments.
#
# Copyright (C) 2018 Red Hat, Inc.
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions of
# the GNU General Public License v.2, or (at your option) any later version.
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY expressed or implied, including the implied warranties of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
# Public License for more details. You should have received a copy of the
# GNU General Public License along with this program; if not, write to the
# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA. Any Red Hat trademarks that are incorporated in the
# source code or documentation are not subject to the GNU General Public
# License and may only be used or replicated with the express permission of
# Red Hat, Inc.
#
from __future__ import absolute_import
from __future__ import unicode_literals
from dnf.i18n import _
import collections
import dnf.cli
from dnf.conf.config import PRIO_DEFAULT
import dnf.exceptions
import libdnf.conf
import logging
import os
import os.path
logger = logging.getLogger('dnf')
ALIASES_DROPIN_DIR = '/etc/dnf/aliases.d/'
ALIASES_CONF_PATH = os.path.join(ALIASES_DROPIN_DIR, 'ALIASES.conf')
ALIASES_USER_PATH = os.path.join(ALIASES_DROPIN_DIR, 'USER.conf')
class AliasesConfig(object):
def __init__(self, path):
self._path = path
self._parser = libdnf.conf.ConfigParser()
self._parser.read(self._path)
@property
def enabled(self):
option = libdnf.conf.OptionBool(True)
try:
option.set(PRIO_DEFAULT, self._parser.getData()["main"]["enabled"])
except IndexError:
pass
return option.getValue()
@property
def aliases(self):
result = collections.OrderedDict()
section = "aliases"
if not self._parser.hasSection(section):
return result
for key in self._parser.options(section):
value = self._parser.getValue(section, key)
if not value:
continue
result[key] = value.split()
return result
class Aliases(object):
def __init__(self):
self.aliases = collections.OrderedDict()
self.conf = None
self.enabled = True
if self._disabled_by_environ():
self.enabled = False
return
self._load_main()
if not self.enabled:
return
self._load_aliases()
def _disabled_by_environ(self):
option = libdnf.conf.OptionBool(True)
try:
option.set(PRIO_DEFAULT, os.environ['DNF_DISABLE_ALIASES'])
return option.getValue()
except KeyError:
return False
except RuntimeError:
logger.warning(
_('Unexpected value of environment variable: '
'DNF_DISABLE_ALIASES=%s'), os.environ['DNF_DISABLE_ALIASES'])
return True
def _load_conf(self, path):
try:
return AliasesConfig(path)
except RuntimeError as e:
raise dnf.exceptions.ConfigError(
_('Parsing file "%s" failed: %s') % (path, e))
except IOError as e:
raise dnf.exceptions.ConfigError(
_('Cannot read file "%s": %s') % (path, e))
def _load_main(self):
try:
self.conf = self._load_conf(ALIASES_CONF_PATH)
self.enabled = self.conf.enabled
except dnf.exceptions.ConfigError as e:
logger.debug(_('Config error: %s'), e)
def _load_aliases(self, filenames=None):
if filenames is None:
try:
filenames = self._dropin_dir_filenames()
except dnf.exceptions.ConfigError:
return
for filename in filenames:
try:
conf = self._load_conf(filename)
if conf.enabled:
self.aliases.update(conf.aliases)
except dnf.exceptions.ConfigError as e:
logger.warning(_('Config error: %s'), e)
def _dropin_dir_filenames(self):
# Get default aliases config filenames:
# all files from ALIASES_DROPIN_DIR,
# and ALIASES_USER_PATH as the last one (-> override all others)
ignored_filenames = [os.path.basename(ALIASES_CONF_PATH),
os.path.basename(ALIASES_USER_PATH)]
def _ignore_filename(filename):
return filename in ignored_filenames or\
filename.startswith('.') or\
not filename.endswith(('.conf', '.CONF'))
filenames = []
try:
if not os.path.exists(ALIASES_DROPIN_DIR):
os.mkdir(ALIASES_DROPIN_DIR)
for fn in sorted(os.listdir(ALIASES_DROPIN_DIR)):
if _ignore_filename(fn):
continue
filenames.append(os.path.join(ALIASES_DROPIN_DIR, fn))
except (IOError, OSError) as e:
raise dnf.exceptions.ConfigError(e)
if os.path.exists(ALIASES_USER_PATH):
filenames.append(ALIASES_USER_PATH)
return filenames
def _resolve(self, args):
stack = []
self.prefix_options = []
def store_prefix(args):
num = 0
for arg in args:
if arg and arg[0] != '-':
break
num += 1
self.prefix_options += args[:num]
return args[num:]
def subresolve(args):
suffix = store_prefix(args)
if (not suffix or # Current alias on stack is resolved
suffix[0] not in self.aliases or # End resolving
suffix[0].startswith('\\')): # End resolving
try:
stack.pop()
# strip the '\' if it exists
if suffix[0].startswith('\\'):
suffix[0] = suffix[0][1:]
except IndexError:
pass
return suffix
if suffix[0] in stack: # Infinite recursion detected
raise dnf.exceptions.Error(
_('Aliases contain infinite recursion'))
# Next word must be an alias
stack.append(suffix[0])
current_alias_result = subresolve(self.aliases[suffix[0]])
if current_alias_result: # We reached non-alias or '\'
return current_alias_result + suffix[1:]
else: # Need to resolve aliases in the rest
return subresolve(suffix[1:])
suffix = subresolve(args)
return self.prefix_options + suffix
def resolve(self, args):
if self.enabled:
try:
args = self._resolve(args)
except dnf.exceptions.Error as e:
logger.error(_('%s, using original arguments.'), e)
return args
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