Calculate the runtime ro.build.id in ota scripts

If the build prop ro.build.id isn't set at build time, init will
set it at runtime. The logic is appending the vbmeta digest to
the ro.build.legacy.id.

Make the same change in ota scripts, so the correct build fingerprint
will be saved in the ota metadata.

Bug: 186786987
Test: generate an OTA, check the metadata
Change-Id: I278f59c41c1f98d4cbea749e5d9e4eaf7a6b9565

tools/releasetools/add_img_to_target_files.py

@@ -420,8 +420,9 @@ def CreateImage(input_dir, info_dict, what, output_file, block_list=None):
     image_props["block_list"] = block_list.name
 
   # Use repeatable ext4 FS UUID and hash_seed UUID (based on partition name and
-  # build fingerprint).
-  build_info = common.BuildInfo(info_dict)
+  # build fingerprint). Also use the legacy build id, because the vbmeta digest
+  # isn't available at this point.
+  build_info = common.BuildInfo(info_dict, use_legacy_id=True)
   uuid_seed = what + "-" + build_info.GetPartitionFingerprint(what)
   image_props["uuid"] = str(uuid.uuid5(uuid.NAMESPACE_URL, uuid_seed))
   hash_seed = "hash_seed-" + uuid_seed

tools/releasetools/common.py

@@ -372,7 +372,10 @@ class BuildInfo(object):
       "product", "product_services", "odm", "vendor", "system"]
   _RO_PRODUCT_PROPS_DEFAULT_SOURCE_ORDER_LEGACY = []
 
-  def __init__(self, info_dict, oem_dicts=None):
+  # The length of vbmeta digest to append to the fingerprint
+  _VBMETA_DIGEST_SIZE_USED = 8
+
+  def __init__(self, info_dict, oem_dicts=None, use_legacy_id=False):
     """Initializes a BuildInfo instance with the given dicts.
 
     Note that it only wraps up the given dicts, without making copies.
@@ -383,6 +386,9 @@ class BuildInfo(object):
           that it always uses the first dict to calculate the fingerprint or the
           device name. The rest would be used for asserting OEM properties only
           (e.g. one package can be installed on one of these devices).
+      use_legacy_id: Use the legacy build id to construct the fingerprint. This
+          is used when we need a BuildInfo class, while the vbmeta digest is
+          unavailable.
 
     Raises:
       ValueError: On invalid inputs.
@@ -391,6 +397,7 @@ class BuildInfo(object):
     self.oem_dicts = oem_dicts
 
     self._is_ab = info_dict.get("ab_update") == "true"
+    self.use_legacy_id = use_legacy_id
 
     # Skip _oem_props if oem_dicts is None to use BuildInfo in
     # sign_target_files_apks
@@ -491,6 +498,9 @@ class BuildInfo(object):
     if prop in BuildInfo._RO_PRODUCT_RESOLVE_PROPS:
       return self._ResolveRoProductBuildProp(prop)
 
+    if prop == "ro.build.id":
+      return self._GetBuildId()
+
     prop_val = self._GetRawBuildProp(prop, None)
     if prop_val is not None:
       return prop_val
@@ -557,6 +567,34 @@ class BuildInfo(object):
 
     return self.GetBuildProp("ro.build.version.release")
 
+  def _GetBuildId(self):
+    build_id = self._GetRawBuildProp("ro.build.id", None)
+    if build_id:
+      return build_id
+
+    legacy_build_id = self.GetBuildProp("ro.build.legacy.id")
+    if not legacy_build_id:
+      raise ExternalError("Couldn't find build id in property file")
+
+    if self.use_legacy_id:
+      return legacy_build_id
+
+    # Append the top 8 chars of vbmeta digest to the existing build id. The
+    # logic needs to match the one in init, so that OTA can deliver correctly.
+    avb_enable = self.info_dict.get("avb_enable") == "true"
+    if not avb_enable:
+      raise ExternalError("AVB isn't enabled when using legacy build id")
+
+    vbmeta_digest = self.info_dict.get("vbmeta_digest")
+    if not vbmeta_digest:
+      raise ExternalError("Vbmeta digest isn't provided when using legacy build"
+                          " id")
+    if len(vbmeta_digest) < self._VBMETA_DIGEST_SIZE_USED:
+      raise ExternalError("Invalid vbmeta digest " + vbmeta_digest)
+
+    digest_prefix = vbmeta_digest[:self._VBMETA_DIGEST_SIZE_USED]
+    return legacy_build_id + '.' + digest_prefix
+
   def _GetPartitionPlatformVersion(self, partition):
     try:
       return self.GetPartitionBuildProp("ro.build.version.release_or_codename",
@@ -790,12 +828,19 @@ def LoadInfoDict(input_file, repacking=False):
   # Set up the salt (based on fingerprint) that will be used when adding AVB
   # hash / hashtree footers.
   if d.get("avb_enable") == "true":
-    build_info = BuildInfo(d)
+    build_info = BuildInfo(d, use_legacy_id=True)
     for partition in PARTITIONS_WITH_BUILD_PROP:
       fingerprint = build_info.GetPartitionFingerprint(partition)
       if fingerprint:
         d["avb_{}_salt".format(partition)] = sha256(
             fingerprint.encode()).hexdigest()
+
+    # Set the vbmeta digest if exists
+    try:
+      d["vbmeta_digest"] = read_helper("META/vbmeta_digest.txt").rstrip()
+    except KeyError:
+      pass
+
   try:
     d["ab_partitions"] = read_helper("META/ab_partitions.txt").split("\n")
   except KeyError:
@@ -1339,7 +1384,7 @@ def ConstructAftlMakeImageCommands(output_image):
 
   vbmeta_image = MakeTempFile()
   os.rename(output_image, vbmeta_image)
-  build_info = BuildInfo(OPTIONS.info_dict)
+  build_info = BuildInfo(OPTIONS.info_dict, use_legacy_id=True)
   version_incremental = build_info.GetBuildProp("ro.build.version.incremental")
   aftltool = OPTIONS.aftl_tool_path
   server_argument_list = [OPTIONS.aftl_server, OPTIONS.aftl_key_path]

tools/releasetools/test_common.py

@@ -48,6 +48,22 @@ def get_2gb_string():
 
 class BuildInfoTest(test_utils.ReleaseToolsTestCase):
 
+  TEST_INFO_FINGERPRINT_DICT = {
+      'build.prop': common.PartitionBuildProps.FromDictionary(
+          'system', {
+              'ro.product.brand': 'product-brand',
+              'ro.product.name': 'product-name',
+              'ro.product.device': 'product-device',
+              'ro.build.version.release': 'version-release',
+              'ro.build.id': 'build-id',
+              'ro.build.version.incremental': 'version-incremental',
+              'ro.build.type': 'build-type',
+              'ro.build.tags': 'build-tags',
+              'ro.build.version.sdk': 30,
+          }
+      ),
+  }
+
   TEST_INFO_DICT = {
       'build.prop': common.PartitionBuildProps.FromDictionary(
           'system', {
@@ -202,6 +218,33 @@ class BuildInfoTest(test_utils.ReleaseToolsTestCase):
         'ro.build.fingerprint'] = 'bad\x80fingerprint'
     self.assertRaises(ValueError, common.BuildInfo, info_dict, None)
 
+  def test_init_goodFingerprint(self):
+    info_dict = copy.deepcopy(self.TEST_INFO_FINGERPRINT_DICT)
+    build_info = common.BuildInfo(info_dict)
+    self.assertEqual(
+      'product-brand/product-name/product-device:version-release/build-id/'
+      'version-incremental:build-type/build-tags', build_info.fingerprint)
+
+    build_props = info_dict['build.prop'].build_props
+    del build_props['ro.build.id']
+    build_props['ro.build.legacy.id'] = 'legacy-build-id'
+    build_info = common.BuildInfo(info_dict, use_legacy_id=True)
+    self.assertEqual(
+      'product-brand/product-name/product-device:version-release/'
+      'legacy-build-id/version-incremental:build-type/build-tags',
+      build_info.fingerprint)
+
+    self.assertRaises(common.ExternalError, common.BuildInfo, info_dict, None,
+                      False)
+
+    info_dict['avb_enable'] = 'true'
+    info_dict['vbmeta_digest'] = 'abcde12345'
+    build_info = common.BuildInfo(info_dict, use_legacy_id=False)
+    self.assertEqual(
+      'product-brand/product-name/product-device:version-release/'
+      'legacy-build-id.abcde123/version-incremental:build-type/build-tags',
+      build_info.fingerprint)
+
   def test___getitem__(self):
     target_info = common.BuildInfo(self.TEST_INFO_DICT, None)
     self.assertEqual('value1', target_info['property1'])