Restore "Check if current ld.config.txt files is backward compatible"

This reverts commit bd2b0c78a1cead7a77bd7a4ec577344ce7e1bb1a.

Reason for revert:
Solved the build error on mac_sdk build by using python2

Bug: 112738739
Bug: 111417344
Test: make ld.config.txt

Change-Id: Ic5a3ed2e6b091813c0310f859b7d20935514a7c6

3 files changed, 192 insertions, 0 deletions

diff --git a/rootdir/Android.mk b/rootdir/Android.mk
index 07f079722..b68dc341a 100644
--- a/rootdir/Android.mk
+++ b/rootdir/Android.mk
@@ -206,6 +206,7 @@ ifeq ($(_enforce_vndk_at_runtime),true)
 LOCAL_MODULE_STEM := $(call append_vndk_version,$(LOCAL_MODULE))
 include $(BUILD_SYSTEM)/base_rules.mk
 ld_config_template := $(LOCAL_PATH)/etc/ld.config.txt
+check_backward_compatibility := true
 vndk_version := $(PLATFORM_VNDK_VERSION)
 include $(LOCAL_PATH)/update_and_install_ld_config.mk
 
@@ -243,6 +244,7 @@ LOCAL_MODULE_PATH := $(TARGET_OUT_ETC)
 LOCAL_MODULE_STEM := $$(LOCAL_MODULE)
 include $(BUILD_SYSTEM)/base_rules.mk
 ld_config_template := $(LOCAL_PATH)/etc/ld.config.txt
+check_backward_compatibility := true
 vndk_version := $(1)
 lib_list_from_prebuilts := true
 include $(LOCAL_PATH)/update_and_install_ld_config.mk
diff --git a/rootdir/ld_config_backward_compatibility_check.py b/rootdir/ld_config_backward_compatibility_check.py
new file mode 100755
index 000000000..1a27578ea
--- /dev/null
+++ b/rootdir/ld_config_backward_compatibility_check.py
@@ -0,0 +1,177 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2018 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 glob
+import os.path
+import re
+import sys
+
+PREBUILTS_VNDK_DIR = "prebuilts/vndk"
+VENDOR_DIRECTORIES = ('/vendor', '/odm')
+
+def find_latest_vndk_snapshot_version():
+  """Returns latest vndk snapshot version in current source tree.
+  It will skip the test if the snapshot directories are not found.
+
+  Returns:
+    latest_version: string
+  """
+  vndk_dir_list = glob.glob(PREBUILTS_VNDK_DIR + "/v*")
+  if not vndk_dir_list:
+    """Exit without error because we may have source trees that do not include
+    VNDK snapshot directories in it.
+    """
+    sys.exit(0)
+  vndk_ver_list = [re.match(r".*/v(\d+)", vndk_dir).group(1)
+                                          for vndk_dir in vndk_dir_list]
+  latest_version = max(vndk_ver_list)
+  if latest_version == '27':
+    """Exit without error because VNDK v27 is not using ld.config.txt template
+    """
+    sys.exit(0)
+  return latest_version
+
+def get_vendor_configuration(ld_config_file):
+  """Reads the ld.config.txt file to parse the namespace configurations.
+  It finds the configurations that include vendor directories.
+
+  Args:
+    ld_config_file: string, path (relative to build top) of the ld.config.txt
+                    file.
+  Returns:
+    configs: dict{string:[string]}, dictionary of namespace configurations.
+             it has 'section + property' names as keys and the directory list
+             as values.
+  """
+  try:
+    conf_file = open(ld_config_file)
+  except IOError:
+    print("error: could not read %s" % ld_config_file)
+    sys.exit(1)
+
+  configs = dict()
+  current_section = None
+
+  with conf_file:
+    for line in conf_file:
+      # ignore comments
+      found = line.find('#')
+      if found != -1:
+        line = line[:found]
+      line = line.strip()
+      if not line:
+        continue
+
+      if line[0] == '[' and line[-1] == ']':
+        # new section started
+        current_section = line[1:-1]
+        continue
+
+      if current_section == None:
+        continue
+
+      found = line.find('+=')
+      opr_len = 2
+      if found == -1:
+        found = line.find('=')
+        opr_len = 1
+      if found == -1:
+        continue
+
+      namespace = line[:found].strip()
+      if not namespace.endswith(".paths"):
+        # check ".paths" only
+        continue
+      namespace = '[' + current_section + ']' + namespace
+      values = line[found + opr_len:].strip()
+      directories = values.split(':')
+
+      for directory in directories:
+        if any(vendor_dir in directory for vendor_dir in VENDOR_DIRECTORIES):
+          if namespace in configs:
+            configs[namespace].append(directory)
+          else:
+            configs[namespace] = [directory]
+
+  return configs
+
+def get_snapshot_config(version):
+  """Finds the ld.config.{version}.txt file from the VNDK snapshot directory.
+  In the vndk prebuilt directory (prebuilts/vndk/v{version}), it searches
+  {arch}/configs/ld.config.{version}.txt file, where {arch} is one of ('arm64',
+  'arm', 'x86_64', 'x86').
+
+  Args:
+    version: string, the VNDK snapshot version to search.
+  Returns:
+    ld_config_file: string, relative path to ld.config.{version}.txt
+  """
+  arch_list = ('arm64', 'arm', 'x86_64', 'x86')
+  for arch in arch_list:
+    ld_config_file = (PREBUILTS_VNDK_DIR
+                + "/v{0}/{1}/configs/ld.config.{0}.txt".format(version, arch))
+    if os.path.isfile(ld_config_file):
+      return ld_config_file
+  print("error: cannot find ld.config.{0}.txt file in snapshot v{0}"
+                                                        .format(version))
+  sys.exit(1)
+
+def check_backward_compatibility(ld_config, vndk_snapshot_version):
+  """Checks backward compatibility for current ld.config.txt file with the
+  old ld.config.txt file. If any of the vendor directories in the old namespace
+  configurations are missing, the test will fail. It is allowed to have new
+  vendor directories in current ld.config.txt file.
+
+  Args:
+    ld_config: string, relative path to current ld.config.txt file.
+    vndk_snapshot_version: string, the VNDK snapshot version that has an old
+                           ld.config.txt file to compare.
+  Returns:
+    result: bool, True if the current configuration is backward compatible.
+  """
+  current_config = get_vendor_configuration(ld_config)
+  old_config = get_vendor_configuration(
+                                get_snapshot_config(vndk_snapshot_version))
+  for namespace in old_config:
+    if namespace not in current_config:
+      print("error: cannot find %s which was provided in ld.config.%s.txt"
+                                        % (namespace, vndk_snapshot_version))
+      return False
+    for path in old_config[namespace]:
+      if not path in current_config[namespace]:
+        print("error: %s for %s in ld.config.%s.txt are missing in %s"
+                % (path, namespace, vndk_snapshot_version, ld_config))
+        return False
+  return True
+
+def main():
+  if len(sys.argv) != 2:
+    print ("Usage: %s target_ld_config_txt_file_name" % sys.argv[0])
+    sys.exit(1)
+
+  latest_vndk_snapshot_version = find_latest_vndk_snapshot_version()
+  if not check_backward_compatibility(sys.argv[1],
+                                          latest_vndk_snapshot_version):
+    print("error: %s has backward incompatible changes to old "
+          "vendor partition." % sys.argv[1])
+    sys.exit(1)
+
+  # Current ld.config.txt file is backward compatible
+  sys.exit(0)
+
+if __name__ == '__main__':
+  main()
diff --git a/rootdir/update_and_install_ld_config.mk b/rootdir/update_and_install_ld_config.mk
index 4d6df77ae..56a30b271 100644
--- a/rootdir/update_and_install_ld_config.mk
+++ b/rootdir/update_and_install_ld_config.mk
@@ -18,10 +18,13 @@
 
 # Read inputs
 ld_config_template := $(strip $(ld_config_template))
+check_backward_compatibility := $(strip $(check_backward_compatibility))
 vndk_version := $(strip $(vndk_version))
 lib_list_from_prebuilts := $(strip $(lib_list_from_prebuilts))
 libz_is_llndk := $(strip $(libz_is_llndk))
 
+compatibility_check_script := \
+  $(LOCAL_PATH)/ld_config_backward_compatibility_check.py
 intermediates_dir := $(call intermediates-dir-for,ETC,$(LOCAL_MODULE))
 library_lists_dir := $(intermediates_dir)
 ifeq ($(lib_list_from_prebuilts),true)
@@ -82,11 +85,19 @@ $(LOCAL_BUILT_MODULE): PRIVATE_VNDK_PRIVATE_LIBRARIES_FILE := $(vndkprivate_libr
 $(LOCAL_BUILT_MODULE): PRIVATE_SANITIZER_RUNTIME_LIBRARIES := $(sanitizer_runtime_libraries)
 $(LOCAL_BUILT_MODULE): PRIVATE_VNDK_VERSION_SUFFIX := $(vndk_version_suffix)
 $(LOCAL_BUILT_MODULE): PRIVATE_INTERMEDIATES_DIR := $(intermediates_dir)
+$(LOCAL_BUILT_MODULE): PRIVATE_COMP_CHECK_SCRIPT := $(compatibility_check_script)
 deps := $(llndk_libraries_file) $(vndksp_libraries_file) $(vndkcore_libraries_file) \
   $(vndkprivate_libraries_file)
+ifeq ($(check_backward_compatibility),true)
+deps += $(compatibility_check_script)
+endif
 
 $(LOCAL_BUILT_MODULE): $(ld_config_template) $(deps)
 	@echo "Generate: $< -> $@"
+ifeq ($(check_backward_compatibility),true)
+	@echo "Checking backward compatibility..."
+	$(hide) $(PRIVATE_COMP_CHECK_SCRIPT) $<
+endif
 	@mkdir -p $(dir $@)
 	$(call private-filter-out-private-libs,$(PRIVATE_LLNDK_LIBRARIES_FILE),$(PRIVATE_INTERMEDIATES_DIR)/llndk_filtered)
 	$(hide) sed -e "s?%LLNDK_LIBRARIES%?$$(cat $(PRIVATE_INTERMEDIATES_DIR)/llndk_filtered)?g" $< >$@
@@ -108,9 +119,11 @@ $(LOCAL_BUILT_MODULE): $(ld_config_template) $(deps)
 	$(hide) rm -f $@.bak
 
 ld_config_template :=
+check_backward_compatibility :=
 vndk_version :=
 lib_list_from_prebuilts :=
 libz_is_llndk :=
+compatibility_check_script :=
 intermediates_dir :=
 library_lists_dir :=
 llndk_libraries_file :=