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# Copyright 2018 - The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Command-line tool to build SEPolicy files."""
import argparse
import os
import subprocess
import sys
import file_utils
# All supported commands in this module.
# For each command, need to add two functions. Take 'build_cil' for example:
# - setup_build_cil()
# - Sets up command parsers and sets default function to do_build_cil().
# - do_build_cil()
_SUPPORTED_COMMANDS = ('build_cil', 'filter_out')
def run_host_command(args, **kwargs):
"""Runs a host command and prints output."""
if kwargs.get('shell'):
command_log = args
else:
command_log = ' '.join(args) # For args as a sequence.
try:
subprocess.check_call(args, **kwargs)
except subprocess.CalledProcessError as err:
sys.stderr.write(
'build_sepolicy - failed to run command: {!r} (ret:{})\n'.format(
command_log, err.returncode))
sys.exit(err.returncode)
def do_build_cil(args):
"""Builds a sepolicy CIL (Common Intermediate Language) file.
This functions invokes some host utils (e.g., secilc, checkpolicy,
version_sepolicy) to generate a .cil file.
Args:
args: the parsed command arguments.
"""
# Determines the raw CIL file name.
input_file_name = os.path.splitext(args.input_policy_conf)[0]
raw_cil_file = input_file_name + '_raw.cil'
# Builds the raw CIL.
file_utils.make_parent_dirs(raw_cil_file)
checkpolicy_cmd = [args.checkpolicy_env]
checkpolicy_cmd += [os.path.join(args.android_host_path, 'checkpolicy'),
'-C', '-M', '-c', args.policy_vers,
'-o', raw_cil_file, args.input_policy_conf]
# Using shell=True to setup args.checkpolicy_env variables.
run_host_command(' '.join(checkpolicy_cmd), shell=True)
file_utils.filter_out([args.reqd_mask], raw_cil_file)
# Builds the output CIL by versioning the above raw CIL.
output_file = args.output_cil
if output_file is None:
output_file = input_file_name + '.cil'
file_utils.make_parent_dirs(output_file)
run_host_command([os.path.join(args.android_host_path, 'version_policy'),
'-b', args.base_policy, '-t', raw_cil_file,
'-n', args.treble_sepolicy_vers, '-o', output_file])
if args.filter_out_files:
file_utils.filter_out(args.filter_out_files, output_file)
# Tests that the output file can be merged with the given CILs.
if args.dependent_cils:
merge_cmd = [os.path.join(args.android_host_path, 'secilc'),
'-m', '-M', 'true', '-G', '-N', '-c', args.policy_vers]
merge_cmd += args.dependent_cils # the give CILs to merge
merge_cmd += [output_file, '-o', '/dev/null', '-f', '/dev/null']
run_host_command(merge_cmd)
def setup_build_cil(subparsers):
"""Sets up command args for 'build_cil' command."""
# Required arguments.
parser = subparsers.add_parser('build_cil', help='build CIL files')
parser.add_argument('-i', '--input_policy_conf', required=True,
help='source policy.conf')
parser.add_argument('-m', '--reqd_mask', required=True,
help='the bare minimum policy.conf to use checkpolicy')
parser.add_argument('-b', '--base_policy', required=True,
help='base policy for versioning')
parser.add_argument('-t', '--treble_sepolicy_vers', required=True,
help='the version number to use for Treble-OTA')
parser.add_argument('-p', '--policy_vers', required=True,
help='SELinux policy version')
# Optional arguments.
parser.add_argument('-c', '--checkpolicy_env',
help='environment variables passed to checkpolicy')
parser.add_argument('-f', '--filter_out_files', nargs='+',
help='the pattern files to filter out the output cil')
parser.add_argument('-d', '--dependent_cils', nargs='+',
help=('check the output file can be merged with '
'the dependent cil files'))
parser.add_argument('-o', '--output_cil', help='the output cil file')
# The function that performs the actual works.
parser.set_defaults(func=do_build_cil)
def do_filter_out(args):
"""Removes all lines in one file that match any line in another file.
Args:
args: the parsed command arguments.
"""
file_utils.filter_out(args.filter_out_files, args.target_file)
def setup_filter_out(subparsers):
"""Sets up command args for 'filter_out' command."""
parser = subparsers.add_parser('filter_out', help='filter CIL files')
parser.add_argument('-f', '--filter_out_files', required=True, nargs='+',
help='the pattern files to filter out the output cil')
parser.add_argument('-t', '--target_file', required=True,
help='target file to filter')
parser.set_defaults(func=do_filter_out)
def run(argv):
"""Sets up command parser and execuates sub-command."""
parser = argparse.ArgumentParser()
# Adds top-level arguments.
parser.add_argument('-a', '--android_host_path', default='',
help='a path to host out executables')
# Adds subparsers for each COMMAND.
subparsers = parser.add_subparsers(title='COMMAND')
for command in _SUPPORTED_COMMANDS:
globals()['setup_' + command](subparsers)
args = parser.parse_args(argv[1:])
args.func(args)
if __name__ == '__main__':
run(sys.argv)