RESTRICT AUTOMERGE Uses a per-partition fingerprint for building images and avb_salt.

This causes the output image files of a merged build to be identical
to the image files of the input partial builds, for each images in
PARTITIONS_WITH_CARE_MAP.

Test: python -m unittest test_common
Test: `m dist`; `unzip out/dist/target_files.zip IMAGES/\*`;
      `zip -d out/dist/target_files.zip IMAGES/\*`
      `add_img_to_target_files -a out/dist/target_files.zip`.
      Verify that the rebuilt images are identical to the deleted ones.
Test: Build a merged target (using merge_target_files.py). Verify that
      the partial target-files.zip IMAGES are identical to the merged
      target-files.zip IMAGES for PARTITIONS_WITH_CARE_MAP images.
Bug: 150405807
Change-Id: I5fdf5783c1aff9c14cf5408090389b1f65b69ca6
(cherry picked from commit d5fe862628)

tools/releasetools/common.py

@@ -319,7 +319,7 @@ class BuildInfo(object):
   OEM-specific properties, some of them will be calculated from two info dicts.
 
   Users can query properties similarly as using a dict() (e.g. info['fstab']),
-  or to query build properties via GetBuildProp() or GetVendorBuildProp().
+  or to query build properties via GetBuildProp() or GetPartitionBuildProp().
 
   Attributes:
     info_dict: The build-time info dict.
@@ -362,16 +362,31 @@ class BuildInfo(object):
     if self._oem_props:
       assert oem_dicts, "OEM source required for this build"
 
+    def check_fingerprint(fingerprint):
+      if (" " in fingerprint or any(ord(ch) > 127 for ch in fingerprint)):
+        raise ValueError(
+            'Invalid build fingerprint: "{}". See the requirement in Android CDD '
+            "3.2.2. Build Parameters.".format(fingerprint))
+
+
+    self._partition_fingerprints = {}
+    for partition in PARTITIONS_WITH_CARE_MAP:
+      try:
+        fingerprint = self.CalculatePartitionFingerprint(partition)
+        check_fingerprint(fingerprint)
+        self._partition_fingerprints[partition] = fingerprint
+      except ExternalError:
+        continue
+    if "system" in self._partition_fingerprints:
+      # system_other is not included in PARTITIONS_WITH_CARE_MAP, but does
+      # need a fingerprint when creating the image.
+      self._partition_fingerprints[
+          "system_other"] = self._partition_fingerprints["system"]
+
     # These two should be computed only after setting self._oem_props.
     self._device = self.GetOemProperty("ro.product.device")
     self._fingerprint = self.CalculateFingerprint()
-
-    # Sanity check the build fingerprint.
-    if (' ' in self._fingerprint or
-        any(ord(ch) > 127 for ch in self._fingerprint)):
-      raise ValueError(
-          'Invalid build fingerprint: "{}". See the requirement in Android CDD '
-          '3.2.2. Build Parameters.'.format(self._fingerprint))
+    check_fingerprint(self._fingerprint)
 
   @property
   def is_ab(self):
@@ -385,28 +400,6 @@ class BuildInfo(object):
   def fingerprint(self):
     return self._fingerprint
 
-  @property
-  def vendor_fingerprint(self):
-    return self._fingerprint_of("vendor")
-
-  @property
-  def product_fingerprint(self):
-    return self._fingerprint_of("product")
-
-  @property
-  def odm_fingerprint(self):
-    return self._fingerprint_of("odm")
-
-  def _fingerprint_of(self, partition):
-    if partition + ".build.prop" not in self.info_dict:
-      return None
-    build_prop = self.info_dict[partition + ".build.prop"]
-    if "ro." + partition + ".build.fingerprint" in build_prop:
-      return build_prop["ro." + partition + ".build.fingerprint"]
-    if "ro." + partition + ".build.thumbprint" in build_prop:
-      return build_prop["ro." + partition + ".build.thumbprint"]
-    return None
-
   @property
   def oem_props(self):
     return self._oem_props
@@ -423,8 +416,22 @@ class BuildInfo(object):
   def items(self):
     return self.info_dict.items()
 
+  def GetPartitionBuildProp(self, prop, partition):
+    """Returns the inquired build property for the provided partition."""
+    # If provided a partition for this property, only look within that
+    # partition's build.prop.
+    if prop in BuildInfo._RO_PRODUCT_RESOLVE_PROPS:
+      prop = prop.replace("ro.product", "ro.product.{}".format(partition))
+    else:
+      prop = prop.replace("ro.", "ro.{}.".format(partition))
+    try:
+      return self.info_dict.get("{}.build.prop".format(partition), {})[prop]
+    except KeyError:
+      raise ExternalError("couldn't find %s in %s.build.prop" %
+                          (prop, partition))
+
   def GetBuildProp(self, prop):
-    """Returns the inquired build property."""
+    """Returns the inquired build property from the standard build.prop file."""
     if prop in BuildInfo._RO_PRODUCT_RESOLVE_PROPS:
       return self._ResolveRoProductBuildProp(prop)
 
@@ -462,19 +469,28 @@ class BuildInfo(object):
 
     raise ExternalError("couldn't resolve {}".format(prop))
 
-  def GetVendorBuildProp(self, prop):
-    """Returns the inquired vendor build property."""
-    try:
-      return self.info_dict.get("vendor.build.prop", {})[prop]
-    except KeyError:
-      raise ExternalError(
-          "couldn't find %s in vendor.build.prop" % (prop,))
-
   def GetOemProperty(self, key):
     if self.oem_props is not None and key in self.oem_props:
       return self.oem_dicts[0][key]
     return self.GetBuildProp(key)
 
+  def GetPartitionFingerprint(self, partition):
+    return self._partition_fingerprints.get(partition, None)
+
+  def CalculatePartitionFingerprint(self, partition):
+    try:
+      return self.GetPartitionBuildProp("ro.build.fingerprint", partition)
+    except ExternalError:
+      return "{}/{}/{}:{}/{}/{}:{}/{}".format(
+          self.GetPartitionBuildProp("ro.product.brand", partition),
+          self.GetPartitionBuildProp("ro.product.name", partition),
+          self.GetPartitionBuildProp("ro.product.device", partition),
+          self.GetPartitionBuildProp("ro.build.version.release", partition),
+          self.GetPartitionBuildProp("ro.build.id", partition),
+          self.GetPartitionBuildProp("ro.build.version.incremental", partition),
+          self.GetPartitionBuildProp("ro.build.type", partition),
+          self.GetPartitionBuildProp("ro.build.tags", partition))
+
   def CalculateFingerprint(self):
     if self.oem_props is None:
       try:
@@ -644,7 +660,10 @@ def LoadInfoDict(input_file, repacking=False):
   # hash / hashtree footers.
   if d.get("avb_enable") == "true":
     build_info = BuildInfo(d)
-    d["avb_salt"] = sha256(build_info.fingerprint).hexdigest()
+    for partition in PARTITIONS_WITH_CARE_MAP:
+      fingerprint = build_info.GetPartitionFingerprint(partition)
+      if fingerprint:
+        d["avb_{}_salt".format(partition)] = sha256(fingerprint).hexdigest()
 
   return d