Update payload library + command-line tool
An initial implementation of a Python module for parsing, checking and
applying a Chrome OS update payload. Comes with a command-line tool
(paycheck.py) for applying such operations on payload files, and a test
script (test_paycheck.sh) for ensuring that the library and tool are
working correctly.
Since update_payload is introduced as a package, we're moving some
previously merged utilities into the package's directory.
(Unit testing for this code will be uploaded on a separate CL; see
chromium-os:39663)
BUG=chromium-os:34911,chromium-os:33607,chromium-os:7597
TEST=test_paycheck.sh successful on MP-signed payloads
CQ-DEPEND=I5746a1d80e822a575f0d96f94d0b4e765fc64507
Change-Id: I77123a1fffbb2059c239b7145c6922968fdffb6a
Reviewed-on: https://gerrit.chromium.org/gerrit/43041
Reviewed-by: Gilad Arnold <[email protected]>
Tested-by: Gilad Arnold <[email protected]>
Reviewed-by: Chris Sosa <[email protected]>
Reviewed-by: Jay Srinivasan <[email protected]>
Reviewed-by: Don Garrett <[email protected]>
Commit-Queue: Gilad Arnold <[email protected]>
diff --git a/scripts/update_payload/common.py b/scripts/update_payload/common.py
new file mode 100644
index 0000000..1650991
--- /dev/null
+++ b/scripts/update_payload/common.py
@@ -0,0 +1,141 @@
+# Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Utilities for update payload processing."""
+
+import ctypes
+import textwrap
+
+from error import PayloadError
+import update_metadata_pb2
+
+
+#
+# Constants.
+#
+PSEUDO_EXTENT_MARKER = ctypes.c_uint64(-1).value
+
+
+#
+# Payload operation types.
+#
+class OpType(object):
+ """Container for operation type constants."""
+ _CLASS = update_metadata_pb2.DeltaArchiveManifest.InstallOperation
+ # pylint: disable=E1101
+ REPLACE = _CLASS.REPLACE
+ REPLACE_BZ = _CLASS.REPLACE_BZ
+ MOVE = _CLASS.MOVE
+ BSDIFF = _CLASS.BSDIFF
+ NAMES = {
+ REPLACE: 'REPLACE',
+ REPLACE_BZ: 'REPLACE_BZ',
+ MOVE: 'MOVE',
+ BSDIFF: 'BSDIFF',
+ }
+
+ def __init__(self):
+ pass
+
+
+#
+# Checker and hashed reading of data.
+#
+def Read(file_obj, length, offset=None, hasher=None):
+ """Reads binary data from a file.
+
+ Args:
+ file_obj: an open file object
+ length: the length of the data to read
+ offset: an offset to seek to prior to reading; this is an absolute offset
+ from either the beginning (non-negative) or end (negative) of the
+ file. (optional)
+ hasher: a hashing object to pass the read data through (optional)
+ Returns:
+ A string containing the read data.
+ Raises:
+ PayloadError if a read error occurred or not enough data was read.
+
+ """
+ if offset is not None:
+ if offset >= 0:
+ file_obj.seek(offset)
+ else:
+ file_obj.seek(offset, 2)
+
+ try:
+ data = file_obj.read(length)
+ except IOError, e:
+ raise PayloadError('error reading from file (%s): %s' % (file_obj.name, e))
+
+ if len(data) != length:
+ raise PayloadError(
+ 'reading from file (%s) too short (%d instead of %d bytes)' %
+ (file_obj.name, len(data), length))
+
+ if hasher:
+ hasher.update(data)
+
+ return data
+
+
+#
+# Formatting functions.
+#
+def FormatExtent(ex, block_size=0):
+ end_block = ex.start_block + ex.num_blocks
+ if block_size:
+ return '%d->%d * %d' % (ex.start_block, end_block, block_size)
+ else:
+ return '%d->%d' % (ex.start_block, end_block)
+
+
+def FormatSha256(digest):
+ """Returns a canonical string representation of a SHA256 digest."""
+ return '\n'.join(textwrap.wrap(digest.encode('hex'), 32))
+
+
+#
+# Useful iterators.
+#
+def _ObjNameIter(items, base_name, reverse=False, name_format_func=None):
+ """A generic (item, name) tuple iterators.
+
+ Args:
+ items: the sequence of objects to iterate on
+ base_name: the base name for all objects
+ reverse: whether iteration should be in reverse order
+ name_format_func: a function to apply to the name string
+ Yields:
+ An iterator whose i-th invocation returns (items[i], name), where name ==
+ base_name + '[i]' (with a formatting function optionally applied to it).
+
+ """
+ idx, inc = (len(items), -1) if reverse else (1, 1)
+ for item in items:
+ item_name = '%s[%d]' % (base_name, idx)
+ if name_format_func:
+ item_name = name_format_func(item, item_name)
+ yield (item, item_name)
+ idx += inc
+
+
+def _OperationNameFormatter(op, op_name):
+ return '%s(%s)' % (op_name, OpType.NAMES.get(op.type, '?'))
+
+
+def OperationIter(operations, base_name, reverse=False):
+ """An (item, name) iterator for update operations."""
+ return _ObjNameIter(operations, base_name, reverse=reverse,
+ name_format_func=_OperationNameFormatter)
+
+
+def ExtentIter(extents, base_name, reverse=False):
+ """An (item, name) iterator for operation extents."""
+ return _ObjNameIter(extents, base_name, reverse=reverse)
+
+
+def SignatureIter(sigs, base_name, reverse=False):
+ """An (item, name) iterator for signatures."""
+ return _ObjNameIter(sigs, base_name, reverse=reverse)
