openstack
/
neutron
Code Issues Proposed changes

Merge "Fix race condition when getting cmdline" into stable/rocky

This commit is contained in:
Zuul 2019-11-29 02:43:40 +00:00 committed by Gerrit Code Review
parent a25561b02a 0304936d21
commit 495312c92a
2 changed files with 26 additions and 11 deletions
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27
neutron/agent/linux/utils.py
View File

@ -313,19 +313,24 @@ def process_is_running(pid):
def get_cmdline_from_pid(pid): def get_cmdline_from_pid(pid):
if not process_is_running(pid): if not process_is_running(pid):
return [] return []
with open('/proc/%s/cmdline' % pid, 'r') as f: # NOTE(jh): Even after the above check, the process may terminate
cmdline = f.readline().split('\0')[:-1] # before the open below happens
try:
with open('/proc/%s/cmdline' % pid, 'r') as f:
cmdline = f.readline().split('\0')[:-1]
except IOError:
return []
# NOTE(slaweq): sometimes it may happen that values in # NOTE(slaweq): sometimes it may happen that values in
# /proc/{pid}/cmdline are separated by space instead of NUL char, # /proc/{pid}/cmdline are separated by space instead of NUL char,
# in such case we would have everything in one element of cmdline_args # in such case we would have everything in one element of cmdline_args
# list and it would not match to expected cmd so we need to try to # list and it would not match to expected cmd so we need to try to
# split it by spaces # split it by spaces
if len(cmdline) == 1: if len(cmdline) == 1:
cmdline = cmdline[0].split(' ') cmdline = cmdline[0].split(' ')
LOG.debug("Found cmdline %s for process with PID %s.", cmdline, pid) LOG.debug("Found cmdline %s for process with PID %s.", cmdline, pid)
return cmdline return cmdline
def cmd_matches_expected(cmd, expected_cmd): def cmd_matches_expected(cmd, expected_cmd):

10
neutron/tests/unit/agent/linux/test_utils.py
View File

@ -336,6 +336,16 @@ class TestGetCmdlineFromPid(base.BaseTestCase):
mock_open.assert_not_called() mock_open.assert_not_called()
self.assertEqual([], cmdline) self.assertEqual([], cmdline)
def test_cmdline_process_disappearing(self):
self.process_is_running_mock.return_value = True
mock_open = self.useFixture(
tools.OpenFixture('/proc/%s/cmdline' % self.pid, 'process')
).mock_open
mock_open.side_effect = IOError()
cmdline = utils.get_cmdline_from_pid(self.pid)
mock_open.assert_called_once_with('/proc/%s/cmdline' % self.pid, 'r')
self.assertEqual([], cmdline)
class TestFindChildPids(base.BaseTestCase): class TestFindChildPids(base.BaseTestCase):