Don't read through symlinks in fsverity_manifest_generator
We're trying to change the build system to remove the need for a
staging directory, where all the files are in the same location
as they are on the device. This means that fsverity_manifest_generator
will no longer be able to read through symlinks, because the files
that the symlink is trying to point to won't be at the same location.
Instead, copy the digests from the actual files pased on on-device
paths after all the files have been processed.
Bug: 394404628
Test: atest ComposHostTestCases
Change-Id: I37bde27797104499ffeaf280068d8a781b5ee660
diff --git a/fsverity/fsverity_manifest_generator.py b/fsverity/fsverity_manifest_generator.py
index ca7ac5c..99e66c6 100644
--- a/fsverity/fsverity_manifest_generator.py
+++ b/fsverity/fsverity_manifest_generator.py
@@ -54,12 +54,29 @@
help='input file for the build manifest')
args = p.parse_args()
+ links = {}
digests = FSVerityDigests()
for f in sorted(args.inputs):
# f is a full path for now; make it relative so it starts with {mount_point}/
- digest = digests.digests[os.path.relpath(f, args.base_dir)]
- digest.digest = _digest(args.fsverity_path, f)
- digest.hash_alg = HASH_ALGORITHM
+ rel = os.path.relpath(f, args.base_dir)
+
+ # Some fsv_meta files are links to other ones. Don't read through the link, because the
+ # layout of files in the build system may not match the layout of files on the device.
+ # Instead, read its target and use it to copy the digest from the real file after all files
+ # are processed.
+ if os.path.islink(f):
+ links[rel] = os.path.normpath(os.path.join(os.path.dirname(rel), os.readlink(f)))
+ else:
+ digest = digests.digests[rel]
+ digest.digest = _digest(args.fsverity_path, f)
+ digest.hash_alg = HASH_ALGORITHM
+
+ for link_rel, real_rel in links.items():
+ if real_rel not in digests.digests:
+ sys.exit(f'There was a fsv_meta symlink to {real_rel}, but that file was not a fsv_meta file')
+ link_digest = digests.digests[link_rel]
+ real_digest = digests.digests[real_rel]
+ link_digest.CopyFrom(real_digest)
manifest = digests.SerializeToString()