[Add] First commit

scripts/imgtool/imglib/boot_record.py

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+
+# Copyright (c) 2019, Arm Limited.
+#
+# 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.
+
+import os
+import sys
+import cbor
+
+
+# SW component IDs
+SW_COMPONENT_RANGE = 0
+SW_COMPONENT_TYPE = SW_COMPONENT_RANGE + 1
+MEASUREMENT_VALUE = SW_COMPONENT_RANGE + 2
+SW_COMPONENT_VERSION = SW_COMPONENT_RANGE + 4
+SIGNER_ID = SW_COMPONENT_RANGE + 5
+MEASUREMENT_DESCRIPTION = SW_COMPONENT_RANGE + 6
+
+
+def create_sw_component_data(sw_type, sw_version, sw_measurement_type,
+                             sw_measurement_value, sw_signer_id):
+
+    # List of SW component claims (key ID + value)
+    key_value_list = [
+        SW_COMPONENT_TYPE, sw_type,
+        SW_COMPONENT_VERSION, sw_version,
+        SIGNER_ID, sw_signer_id,
+        MEASUREMENT_DESCRIPTION, sw_measurement_type,
+        MEASUREMENT_VALUE, sw_measurement_value
+    ]
+    # The measurement value should be the last item (key + value) in the list
+    # to make it easier to modify its value later in the bootloader.
+    # A dictionary would be the best suited data structure to store these
+    # key-value pairs (claims), however dictionaries are not sorted, but for
+    # example the lists do keep to order of items which we care about now.
+    # An ordered dictionary could be used instead, but it would be converted
+    # to a dict before the encoding and this conversion may not keep the order
+    # of the items.
+
+    if (len(key_value_list) % 2) != 0:
+        print('Error: The length of the sw component claim list must '
+              'be even (key + value).', file=sys.stderr)
+        sys.exit(1)
+    else:
+        claim_number = (int)(len(key_value_list) / 2)
+
+    # The output of this function must be a CBOR encoded map (dictionary) of
+    # the SW component claims. The CBOR representation of an array and a map
+    # (dictionary) is quite similar. To convert the encoded list to a map, it
+    # is enough to modify the first byte (CBOR data item header) of the
+    # data. This applies up to 23 items (11 claims in this case) - until the 5
+    # lower bits of the item header are used as an item count specifier.
+
+    if claim_number > 11:
+        print('Error: There are more than 11 claims in the '
+              'list of sw component claims.', file=sys.stderr)
+        sys.exit(1)
+
+    record_array = bytearray(cbor.dumps(key_value_list))
+    # Modify the CBOR data item header (from array to map)
+    # 7..5 bits : Major type
+    #             Array - 0x80
+    #             Map   - 0xA0
+    # 4..0 bits : Number of items
+    record_array[0] = 0xA0 + claim_number
+
+    return bytes(record_array)