sstate.bbclass: Remove possibility of file corruption and make package writing atomic

There is currently a race window when creating sstate packages since we don't
atomically write the files to SSTATE_DIR. This change ensures we do so by writing
to a temporary file and then doing an atomic move.

(From OE-Core rev: 52bf113e786a57123a9da98f64442afbc2f1471e)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/meta/classes/sstate.bbclass b/meta/classes/sstate.bbclass
index 15706541ae..20e66e2742 100644
--- a/meta/classes/sstate.bbclass
+++ b/meta/classes/sstate.bbclass
@@ -455,12 +455,14 @@ python sstate_task_postfunc () {
 #
 sstate_create_package () {
         cd ${SSTATE_BUILDDIR}
+        TFILE=`mktemp ${SSTATE_PKG}.XXXXXXXX`
         # Need to handle empty directories
         if [ "$(ls -A)" ]; then
-                tar -czf ${SSTATE_PKG} *
+                tar -czf $TFILE *
         else
-                tar -cz --file=${SSTATE_PKG} --files-from=/dev/null
+                tar -cz --file=$TFILE --files-from=/dev/null
         fi
+        mv $TFILE ${SSTATE_PKG}
 
         cd ${WORKDIR}
         rm -rf ${SSTATE_BUILDDIR}