paycheck.py revision d013028f4c07bec6db9563a04b14d465c3c06b05 
1#!/usr/bin/python
2#
3# Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
4# Use of this source code is governed by a BSD-style license that can be
5# found in the LICENSE file.
6
7"""Command-line tool for checking and applying Chrome OS update payloads."""
8
9import optparse
10import os
11import sys
12
13# pylint: disable=F0401
14lib_dir = os.path.join(os.path.dirname(__file__), 'lib')
15if os.path.exists(lib_dir) and os.path.isdir(lib_dir):
16  sys.path.insert(1, lib_dir)
17import update_payload
18
19
20# The default sizes of partitions, based on current partitioning practice.
21_DEFAULT_ROOTFS_PART_SIZE = 2 * 1024 * 1024 * 1024
22_DEFAULT_KERNEL_PART_SIZE = 16 * 1024 * 1024
23
24_TYPE_FULL = 'full'
25_TYPE_DELTA = 'delta'
26
27
28def ParseArguments(argv):
29  """Parse and validate command-line arguments.
30
31  Args:
32    argv: command-line arguments to parse (excluding the program name)
33  Returns:
34    A tuple (opts, payload, extra_args), where `opts' are the options
35    returned by the parser, `payload' is the name of the payload file
36    (mandatory argument) and `extra_args' are any additional command-line
37    arguments.
38
39  """
40  parser = optparse.OptionParser(
41      usage=('Usage: %prog [OPTION...] PAYLOAD [DST_KERN DST_ROOT '
42             '[SRC_KERN SRC_ROOT]]'),
43      description=('Applies a Chrome OS update PAYLOAD to SRC_KERN and '
44                   'SRC_ROOT emitting DST_KERN and DST_ROOT, respectively. '
45                   'SRC_KERN and SRC_ROOT are only needed for delta payloads. '
46                   'When no partitions are provided, verifies the payload '
47                   'integrity.'),
48      epilog=('Note: a payload may verify correctly but fail to apply, and '
49              'vice versa; this is by design and can be thought of as static '
50              'vs dynamic correctness. A payload that both verifies and '
51              'applies correctly should be safe for use by the Chrome OS '
52              'Update Engine. Use --check to verify a payload prior to '
53              'applying it.'))
54
55  default_key = os.path.join(lib_dir,
56                             'update_payload/update-payload-key.pub.pem')
57
58  check_opts = optparse.OptionGroup(parser, 'Payload integrity checking')
59  check_opts.add_option('-c', '--check', action='store_true', default=False,
60                        help=('force payload integrity check (e.g. before '
61                              'applying)'))
62  check_opts.add_option('-r', '--report', metavar='FILE',
63                        help="dump payload report (`-' for stdout)")
64  check_opts.add_option('-t', '--type', metavar='TYPE', dest='assert_type',
65                        help=("assert that payload is either `%s' or `%s'" %
66                              (_TYPE_FULL, _TYPE_DELTA)))
67  check_opts.add_option('-z', '--block-size', metavar='NUM', default=0,
68                        type='int',
69                        help='assert a non-default (4096) payload block size')
70  check_opts.add_option('-u', '--allow-unhashed', action='store_true',
71                        default=False, help='allow unhashed operations')
72  check_opts.add_option('-d', '--disabled_tests', metavar='TESTLIST',
73                        default=(),
74                        help=('comma-separated list of tests to disable; '
75                              'available values: ' +
76                              ', '.join(update_payload.CHECKS_TO_DISABLE)))
77  check_opts.add_option('-k', '--key', metavar='FILE', default=default_key,
78                        help=('Override standard key used for signature '
79                              'validation'))
80  check_opts.add_option('-m', '--meta-sig', metavar='FILE',
81                        help='verify metadata against its signature')
82  check_opts.add_option('-p', '--root-part-size', metavar='NUM',
83                        default=_DEFAULT_ROOTFS_PART_SIZE, type='int',
84                        help=('override default (%default) rootfs partition '
85                              'size'))
86  check_opts.add_option('-P', '--kern-part-size', metavar='NUM',
87                        default=_DEFAULT_KERNEL_PART_SIZE, type='int',
88                        help=('override default (%default) kernel partition '
89                              'size'))
90
91  parser.add_option_group(check_opts)
92
93  trace_opts = optparse.OptionGroup(parser, 'Block tracing')
94  trace_opts.add_option('-b', '--root-block', metavar='BLOCK', type='int',
95                        help='trace the origin for a rootfs block')
96  trace_opts.add_option('-B', '--kern-block', metavar='BLOCK', type='int',
97                        help='trace the origin for a kernel block')
98  trace_opts.add_option('-s', '--skip', metavar='NUM', default='0', type='int',
99                        help='skip first NUM occurrences of traced block')
100  parser.add_option_group(trace_opts)
101
102  # Parse command-line arguments.
103  opts, args = parser.parse_args(argv)
104
105  # Validate a value given to --type, if any.
106  if opts.assert_type not in (None, _TYPE_FULL, _TYPE_DELTA):
107    parser.error('invalid argument to --type: %s' % opts.assert_type)
108
109  # Convert and validate --disabled_tests value list, if provided.
110  if opts.disabled_tests:
111    opts.disabled_tests = opts.disabled_tests.split(',')
112    for test in opts.disabled_tests:
113      if test not in update_payload.CHECKS_TO_DISABLE:
114        parser.error('invalid argument to --disabled_tests: %s' % test)
115
116  # Ensure consistent use of block tracing options.
117  do_block_trace = opts.root_block or opts.kern_block
118  if opts.skip and not do_block_trace:
119    parser.error('--skip must be used with either --root-block or --kern-block')
120
121  # There are several options that imply --check.
122  opts.check = (opts.check or opts.report or opts.assert_type or
123                opts.block_size or opts.allow_unhashed or
124                opts.disabled_tests or opts.meta_sig or
125                opts.key != default_key or
126                opts.root_part_size != _DEFAULT_ROOTFS_PART_SIZE or
127                opts.kern_part_size != _DEFAULT_KERNEL_PART_SIZE)
128
129  # Check number of arguments, enforce payload type accordingly.
130  if len(args) == 3:
131    if opts.assert_type == _TYPE_DELTA:
132      parser.error('%s payload requires source partition arguments' %
133                   _TYPE_DELTA)
134    opts.assert_type = _TYPE_FULL
135  elif len(args) == 5:
136    if opts.assert_type == _TYPE_FULL:
137      parser.error('%s payload does not accept source partition arguments' %
138                   _TYPE_FULL)
139    opts.assert_type = _TYPE_DELTA
140  elif len(args) == 1:
141    # Not applying payload; if block tracing not requested either, do an
142    # integrity check.
143    if not do_block_trace:
144      opts.check = True
145  else:
146    parser.error('unexpected number of arguments')
147
148  # By default, look for a metadata-signature file with a name based on the name
149  # of the payload we are checking. We only do it when check is triggered and a
150  # public key provided, so as not to force a metadata signature to fail.
151  if opts.check and opts.key and not opts.meta_sig:
152    default_meta_sig = args[0] + '.metadata-signature'
153    if os.path.isfile(default_meta_sig):
154      opts.meta_sig = default_meta_sig
155      print >> sys.stderr, 'Using default metadata signature', opts.meta_sig
156
157  return opts, args[0], args[1:]
158
159
160def main(argv):
161  # Parse and validate arguments.
162  options, payload_file_name, extra_args = ParseArguments(argv[1:])
163
164  with open(payload_file_name) as payload_file:
165    payload = update_payload.Payload(payload_file)
166    try:
167      # Initialize payload.
168      payload.Init()
169
170      # Perform payload integrity checks.
171      if options.check:
172        report_file = None
173        do_close_report_file = False
174        try:
175          if options.report:
176            if options.report == '-':
177              report_file = sys.stdout
178            else:
179              report_file = open(options.report, 'w')
180              do_close_report_file = True
181
182          metadata_sig_file = (
183              open(options.meta_sig) if options.meta_sig else None)
184          payload.Check(
185              pubkey_file_name=options.key,
186              metadata_sig_file=metadata_sig_file,
187              report_out_file=report_file,
188              assert_type=options.assert_type,
189              block_size=int(options.block_size),
190              rootfs_part_size=options.root_part_size,
191              kernel_part_size=options.kern_part_size,
192              allow_unhashed=options.allow_unhashed,
193              disabled_tests=options.disabled_tests)
194        finally:
195          if do_close_report_file:
196            report_file.close()
197
198      # Trace blocks.
199      if options.root_block is not None:
200        payload.TraceBlock(options.root_block, options.skip, sys.stdout, False)
201      if options.kern_block is not None:
202        payload.TraceBlock(options.kern_block, options.skip, sys.stdout, True)
203
204      # Apply payload.
205      if extra_args:
206        if options.assert_type == _TYPE_FULL:
207          payload.Apply(extra_args[0], extra_args[1])
208        elif options.assert_type == _TYPE_DELTA:
209          payload.Apply(extra_args[0], extra_args[1],
210                        src_kernel_part=extra_args[2],
211                        src_rootfs_part=extra_args[3])
212        else:
213          assert False, 'cannot get here'
214
215    except update_payload.PayloadError, e:
216      sys.stderr.write('Error: %s\n' % e)
217      return 1
218
219  return 0
220
221
222if __name__ == '__main__':
223  sys.exit(main(sys.argv))
224