[PATCH] sstate: remove corrupted artifacts from local mirror

[Max Yu <yumx@amazon.com>]

We observe sstate cache corruptions sometimes which cause rebuilds. That is not
a fatal error as the package has to be rebuilt and updated artifact needs to be
pushed to remote sstate cache mirror. Currently, Yocto does not handle
corruptions properly, where the corrupted artifact is not deleted or
renamed. Later, after the package is built the same corrupted artifact is pushed
to remote mirror and the same procedure is circled again and again.

This change verifies the outcome of the unpacking action and renames the
artifact if a fatal error occurred ("tar" tool returns error 2). In such case we
rename the artifact what causes that a proper one is created and uploaded
overwriting the exisiting one - the corrupted one - in the remote mirror. That
way we break the loop of uploading corrupted file again and again.

Suggested-by: Przemyslaw Sobon <psobon@amazon.com>
Signed-off-by: Max Yu <yumx@amazon.com>
---
 meta/classes-global/sstate.bbclass | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/meta/classes-global/sstate.bbclass b/meta/classes-global/sstate.bbclass
index 11bb892a42..5a7ce35341 100644
--- a/meta/classes-global/sstate.bbclass
+++ b/meta/classes-global/sstate.bbclass
@@ -937,7 +937,12 @@ sstate_unpack_package () {
 		ZSTD="pzstd -p ${ZSTD_THREADS}"
 	fi
 
-	tar -I "$ZSTD" -xvpf ${SSTATE_PKG}
+	if ! tar -I "$ZSTD" -xvpf ${SSTATE_PKG}; then
+		echo "Fatal error extracting sstate cache artifacts, file might be corrupted or truncated, renaming"
+		mv ${SSTATE_PKG} ${SSTATE_PKG}.unpack_error
+		exit 2
+	fi
+
 	# update .siginfo atime on local/NFS mirror if it is a symbolic link
 	[ ! -h ${SSTATE_PKG}.siginfo ] || [ ! -e ${SSTATE_PKG}.siginfo ] || touch -a ${SSTATE_PKG}.siginfo 2>/dev/null || true
 	# update each symbolic link instead of any referenced file
-- 
2.40.1