upload android base code part6

android/system/extras/verity/build_verity_metadata.py

@@ -0,0 +1,112 @@
+#! /usr/bin/env python
+#
+# Copyright (C) 2013 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.
+
+import argparse
+import os
+import sys
+import struct
+import shlex
+import subprocess
+import tempfile
+
+VERSION = 0
+MAGIC_NUMBER = 0xb001b001
+BLOCK_SIZE = 4096
+METADATA_SIZE = BLOCK_SIZE * 8
+
+def run(cmd):
+    p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
+    output, _ = p.communicate()
+    print output
+    if p.returncode:
+        exit(-1)
+
+def get_verity_metadata_size(data_size):
+    return METADATA_SIZE
+
+def build_metadata_block(verity_table, signature):
+    table_len = len(verity_table)
+    block = struct.pack("II256sI", MAGIC_NUMBER, VERSION, signature, table_len)
+    block += verity_table
+    block = block.ljust(METADATA_SIZE, '\x00')
+    return block
+
+def sign_verity_table(table, signer_path, key_path, signer_args=None):
+    with tempfile.NamedTemporaryFile(suffix='.table') as table_file:
+        with tempfile.NamedTemporaryFile(suffix='.sig') as signature_file:
+            table_file.write(table)
+            table_file.flush()
+            if signer_args is None:
+              cmd = [signer_path, table_file.name, key_path, signature_file.name]
+            else:
+              args_list = shlex.split(signer_args)
+              cmd = [signer_path] + args_list + [table_file.name, key_path, signature_file.name]
+            print cmd
+            run(cmd)
+            return signature_file.read()
+
+def build_verity_table(block_device, data_blocks, root_hash, salt):
+    table = "1 %s %s %s %s %s %s sha256 %s %s"
+    table %= (  block_device,
+                block_device,
+                BLOCK_SIZE,
+                BLOCK_SIZE,
+                data_blocks,
+                data_blocks,
+                root_hash,
+                salt)
+    return table
+
+def build_verity_metadata(data_blocks, metadata_image, root_hash, salt,
+        block_device, signer_path, signing_key, signer_args=None):
+    # build the verity table
+    verity_table = build_verity_table(block_device, data_blocks, root_hash, salt)
+    # build the verity table signature
+    signature = sign_verity_table(verity_table, signer_path, signing_key, signer_args)
+    # build the metadata block
+    metadata_block = build_metadata_block(verity_table, signature)
+    # write it to the outfile
+    with open(metadata_image, "wb") as f:
+        f.write(metadata_block)
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    subparsers = parser.add_subparsers()
+
+    parser_size = subparsers.add_parser('size')
+    parser_size.add_argument('partition_size', type=int, action='store', help='partition size')
+    parser_size.set_defaults(dest='size')
+
+    parser_build = subparsers.add_parser('build')
+    parser_build.add_argument('blocks', type=int, help='data image blocks')
+    parser_build.add_argument('metadata_image', action='store', help='metadata image')
+    parser_build.add_argument('root_hash', action='store', help='root hash')
+    parser_build.add_argument('salt', action='store', help='salt')
+    parser_build.add_argument('block_device', action='store', help='block device')
+    parser_build.add_argument('signer_path', action='store', help='verity signer path')
+    parser_build.add_argument('signing_key', action='store', help='verity signing key')
+    parser_build.add_argument('--signer_args', action='store', help='verity signer args')
+    parser_build.set_defaults(dest='build')
+
+    args = parser.parse_args()
+
+    if args.dest == 'size':
+        print get_verity_metadata_size(args.partition_size)
+    else:
+        build_verity_metadata(args.blocks / 4096, args.metadata_image,
+                              args.root_hash, args.salt, args.block_device,
+                              args.signer_path, args.signing_key,
+                              args.signer_args)