tc-testing: Add command timeout feature to tdc

Using an attribute set in the tdc_config.py file, limit the
amount of time tdc will wait for an executed command to
complete and prevent the script from hanging entirely.

This timeout will be applied to all executed commands.

Signed-off-by: Lucas Bates <lucasb@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 13 insertions, 5 deletions

diff --git a/tools/testing/selftests/tc-testing/tdc.py b/tools/testing/selftests/tc-testing/tdc.py
index 7607ba3e3cbe..b862ee5c44b5 100755
--- a/tools/testing/selftests/tc-testing/tdc.py
+++ b/tools/testing/selftests/tc-testing/tdc.py
@@ -131,12 +131,16 @@ def exec_cmd(args, pm, stage, command):
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         env=ENVIR)
-    (rawout, serr) = proc.communicate()
 
-    if proc.returncode != 0 and len(serr) > 0:
-        foutput = serr.decode("utf-8", errors="ignore")
-    else:
-        foutput = rawout.decode("utf-8", errors="ignore")
+    try:
+        (rawout, serr) = proc.communicate(timeout=NAMES['TIMEOUT'])
+        if proc.returncode != 0 and len(serr) > 0:
+            foutput = serr.decode("utf-8", errors="ignore")
+        else:
+            foutput = rawout.decode("utf-8", errors="ignore")
+    except subprocess.TimeoutExpired:
+        foutput = "Command \"{}\" timed out\n".format(command)
+        proc.returncode = 255
 
     proc.stdout.close()
     proc.stderr.close()
@@ -438,6 +442,8 @@ def check_default_settings(args, remaining, pm):
         NAMES['TC'] = args.path
     if args.device != None:
         NAMES['DEV2'] = args.device
+    if 'TIMEOUT' not in NAMES:
+        NAMES['TIMEOUT'] = None
     if not os.path.isfile(NAMES['TC']):
         print("The specified tc path " + NAMES['TC'] + " does not exist.")
         exit(1)
diff --git a/tools/testing/selftests/tc-testing/tdc_config.py b/tools/testing/selftests/tc-testing/tdc_config.py
index d651bc1501bd..6d91e48c2625 100644
--- a/tools/testing/selftests/tc-testing/tdc_config.py
+++ b/tools/testing/selftests/tc-testing/tdc_config.py
@@ -15,6 +15,8 @@ NAMES = {
           'DEV1': 'v0p1',
           'DEV2': '',
           'BATCH_FILE': './batch.txt',
+          # Length of time in seconds to wait before terminating a command
+          'TIMEOUT': 12,
           # Name of the namespace to use
           'NS': 'tcut',
           # Directory containing eBPF test programs