bitbake: checksum: sanity check path when recursively checksumming

In case something goes tragically wrong, catch a request to checksum / and
refuse.

(Bitbake rev: 8bd16328a9332c57b03198826e22b48fadcd21d9)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/checksum.py

@@ -97,6 +97,8 @@ class FileChecksumCache(MultiProcessCache):
 
         def checksum_dir(pth):
             # Handle directories recursively
+            if pth == "/":
+                bb.fatal("Refusing to checksum /")
             dirchecksums = []
             for root, dirs, files in os.walk(pth):
                 for name in files: