build_library: support multi-arch in generate_au_zip

To be able to support arm64 native SDK without cross builds, we should
make generate_au_zip support both architectures, amd64 and arm64.
Without doing that, `build_image` fails with `ERROR : Required
WHITE_LIST items ld-linux-x86-64.so.2 not found!!!`, because the
script recognizes only amd64 libs in WHITE_LIST.

We should first determine the architecture in build_image, before
running generate_au_zip, and pass the architecture, either amd64 or
arm64. Also add allow_list and ld_linux parameters to necessary
functions.

build_library/build_image_util.sh

@@ -83,7 +83,7 @@ zip_update_tools() {
   # Make sure some vars this script needs are exported
   export REPO_MANIFESTS_DIR SCRIPTS_DIR
   "${BUILD_LIBRARY_DIR}/generate_au_zip.py" \
-    --output-dir "${BUILD_DIR}" --zip-name "${update_zip}"
+    --arch "$(get_sdk_arch)" --output-dir "${BUILD_DIR}" --zip-name "${update_zip}"
 
   upload_image "${BUILD_DIR}/${update_zip}"
 }

build_library/generate_au_zip.py

@@ -32,6 +32,9 @@ DYNAMIC_EXECUTABLES = ['/usr/bin/delta_generator',
                        '/usr/bin/bsdiff',
                        '/usr/bin/bspatch']
 
+LD_LINUX_AMD64 = 'ld-linux-x86-64.so.2'
+LD_LINUX_ARM64 = 'ld-linux-aarch64.so.1'
+
 # These files will be ignored when present in the dependancy list.
 DENY_LIST = [
     # This library does not exist on disk, but is inserted into the
@@ -40,9 +43,14 @@ DENY_LIST = [
     ]
 
 # These files MUST be present in the dependancy list.
-ALLOW_LIST = [
+# Update WrapExecutableFiles if this file changes names.
-    # Update WrapExecutableFiles if this file changes names
+# Each architecture requires different allow list libs.
-    'ld-linux-x86-64.so.2',
+ALLOW_LIST_AMD64 = [
+    LD_LINUX_AMD64,
+    ]
+
+ALLOW_LIST_ARM64 = [
+    LD_LINUX_ARM64,
     ]
 
 LIB_DIR = 'lib.so'
@@ -93,7 +101,7 @@ def _SplitAndStrip(data):
   return return_list
 
 
-def DepsToCopy(ldd_files):
+def DepsToCopy(ldd_files, allow_list):
   """Returns a list of deps for a given dynamic executables list.
     Args:
       ldd_files: List of dynamic files that needs to have the deps evaluated
@@ -130,11 +138,11 @@ def DepsToCopy(ldd_files):
       sys.exit(1)
 
   result = _ExcludeDenylist(list(libs), DENY_LIST)
-  _EnforceAllowList(list(libs), ALLOW_LIST)
+  _EnforceAllowList(list(libs), allow_list=allow_list)
   return result
 
 
-def CopyRequiredFiles(dest_files_root):
+def CopyRequiredFiles(dest_files_root, allow_list):
   """Generates a list of files that are required for au-generator zip file
     Args:
       dest_files_root: location of the directory where we should copy the files
@@ -161,7 +169,7 @@ def CopyRequiredFiles(dest_files_root):
       logging.exception("Copying '%s' to %s failed", file_name, dest_files_root)
       sys.exit(1)
 
-  libraries = DepsToCopy(ldd_files=DYNAMIC_EXECUTABLES)
+  libraries = DepsToCopy(ldd_files=DYNAMIC_EXECUTABLES, allow_list=allow_list)
   lib_dir = os.path.join(dest_files_root, LIB_DIR)
   os.mkdir(lib_dir)
   for file_name in libraries:
@@ -188,7 +196,7 @@ def CopyRequiredFiles(dest_files_root):
     sys.exit(1)
 
 
-def WrapExecutableFiles(dest_files_root):
+def WrapExecutableFiles(dest_files_root, ld_linux):
   """Our dynamically linked executalbes have to be invoked use the library
      versions they were linked with inside the chroot (from libc on), as well
      as the dynamic linker they were built with inside the chroot.
@@ -209,10 +217,10 @@ def WrapExecutableFiles(dest_files_root):
       script.write('# Auto-generated wrapper script\n')
       script.write('thisdir="$(dirname "$0")"\n')
       script.write('LD_LIBRARY_PATH=\n')
-      script.write('exec "$thisdir/%s/ld-linux-x86-64.so.2"'
+      script.write('exec "$thisdir/%s/%s"'
                    ' --library-path "$thisdir/%s"'
                    ' "$thisdir/%s.bin" "$@"\n' %
-                   (LIB_DIR, LIB_DIR, base_exec))
+                   (LIB_DIR, ld_linux, LIB_DIR, base_exec))
 
 
 def CleanUp(temp_dir):
@@ -335,6 +343,8 @@ def main():
                     default='au-generator.zip', help='Name of the zip file')
   parser.add_option('-k', '--keep-temp', dest='keep_temp', default=False,
                     action='store_true', help='Keep the temp files...',)
+  parser.add_option('-a', '--arch', dest='arch',
+                     default='amd64', help='Arch amd64/arm64. Default: amd64',)
 
   (options, args) = parser.parse_args()
   if options.debug:
@@ -345,8 +355,16 @@ def main():
   temp_dir = CreateTempDir()
   dest_files_root = os.path.join(temp_dir, 'au-generator')
   os.makedirs(dest_files_root)
-  CopyRequiredFiles(dest_files_root=dest_files_root)
+
-  WrapExecutableFiles(dest_files_root=dest_files_root)
+  if options.arch == 'arm64':
+    ld_linux = LD_LINUX_ARM64
+    allow_list = ALLOW_LIST_ARM64
+  else:
+    ld_linux = LD_LINUX_AMD64
+    allow_list = ALLOW_LIST_AMD64
+
+  CopyRequiredFiles(dest_files_root=dest_files_root, allow_list=allow_list)
+  WrapExecutableFiles(dest_files_root=dest_files_root, ld_linux=ld_linux)
   zip_file_name = os.path.join(temp_dir, options.zip_name)
   GenerateZipFile(zip_file_name, dest_files_root)
   CopyZipToFinalDestination(options.output_dir, zip_file_name)