selftests: bpf: Skip write only files in debugfs

DebugFS for netdevsim now contains some "action trigger" files
which are write only. Don't try to capture the contents of those.

Note that we can't use os.access() because the script requires
root.

Fixes: 4418f862d675 ("netdevsim: implement support for devlink region and snapshots")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/tools/testing/selftests/bpf/test_offload.py b/tools/testing/selftests/bpf/test_offload.py
index 15a666329a34df435dad7021845c0cbb377fb615..1afa22c88e42a85e49a299eb1e0ff72f8fbbae3d 100755 (executable)
--- a/tools/testing/selftests/bpf/test_offload.py
+++ b/tools/testing/selftests/bpf/test_offload.py
@@ -22,6 +22,7 @@ import os
 import pprint
 import random
 import re
+import stat
 import string
 import struct
 import subprocess
@@ -311,7 +312,11 @@ class DebugfsDir:
         for f in out.split():
             if f == "ports":
                 continue
+
             p = os.path.join(path, f)
+            if not os.stat(p).st_mode & stat.S_IRUSR:
+                continue
+
             if os.path.isfile(p):
                 _, out = cmd('cat %s/%s' % (path, f))
                 dfs[f] = out.strip()