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#!/usr/bin/env python3
# libpulp - User-space Livepatching Library
#
# Copyright (C) 2020-2021 SUSE Software Solutions GmbH
#
# This file is part of libpulp.
#
# libpulp is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# libpulp is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with libpulp. If not, see <http://www.gnu.org/licenses/>.
import subprocess
import testsuite
# Since the deadlock demonstrated by this test case does not occur
# everytime it executes, run it in a loop. The amount of iterations
# hardcoded is arbitrary
errors = 0
child = testsuite.spawn('deadlock', log=None)
child.expect('Waiting for input.')
child.sendline('')
child.expect('hello')
# Applying a live patch to a process entails stopping all of its
# threads, then stealing one of them to jack into the process and call
# libpulp.so's routines that load and apply the live patch. These
# routines are called from the context of a signal-handler, and, as
# such, should not make calls to Asynchronous Signal Unsafe functions.
# However, libpulp calls dlopen, which is AS-Unsafe.
for attempt in range(200):
print(' Attempt #' + str(attempt))
try:
child.livepatch('libblocked_livepatch1.ulp', timeout=10)
except subprocess.TimeoutExpired:
print('Deadlock detected.')
errors = 1
break
except subprocess.CalledProcessError:
pass
else:
break
child.close(force=True)
exit(errors)
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