From 3d5ae80f50c468b82e0cdf5765a1e722919a9941 Mon Sep 17 00:00:00 2001
From: Inseob Kim <inseob@google.com>
Date: Fri, 7 Jan 2022 10:56:17 +0900
Subject: [PATCH] Write signature size even when it's empty

Normally this has no effect, but when we generate metadata for small
files (<=4KB), merkle tree isn't generated. In such case, writing zero
will make the metadata format simpler and unconditional.

Test: manual
Change-Id: Ibe18175b580af3409c896a8bb97323792ad9c459
---
 tools/releasetools/fsverity_metadata_generator.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/releasetools/fsverity_metadata_generator.py b/tools/releasetools/fsverity_metadata_generator.py
index a300d2e932..fa7cd3934a 100644
--- a/tools/releasetools/fsverity_metadata_generator.py
+++ b/tools/releasetools/fsverity_metadata_generator.py
@@ -178,6 +178,7 @@ class FSVerityMetadataGenerator:
           out.write(sig)
       else:
         out.write(pack('<I', SIG_TYPE_NONE))
+        out.write(pack('<I', 0))
 
       # 4. merkle tree
       with open(merkletree_file, 'rb') as f: