blob: 61da9516223b505913ec6585b0af4a347e7f0cea [file] [log] [blame]
# Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""A Python utility library for TPM module testing."""
import logging, subprocess, time
from autotest_lib.client.common_lib import error
def runInSubprocess(args, rc_list=None):
"""Run a command in subprocess and return stdout.
args: a list of string, command to run.
rc_list: a list of int, acceptable return code values.
out: a string, stdout of the command executed.
err: a string, stderr of the command executed, or None.
RuntimeError: if subprocess return code is non-zero and not in rc_list.
if rc_list is None:
rc_list = []
# Sleep for 1 second so we don't overwhelm I2C bus with too many commands
logging.debug('runInSubprocess args = %r; rc_list = %r', args, rc_list)
proc = subprocess.Popen(args,
out, err = proc.communicate()
logging.error('runInSubprocess %s: out=%r, err=%r', args[0], out, err)
if proc.returncode and proc.returncode not in rc_list:
raise RuntimeError('runInSubprocess %s failed with returncode %d: %s' %
(args[0], proc.returncode, out))
return str(out), str(err)
def enableI2C():
"""Enable i2c-dev so i2c-tools can be used.
Dependency: 'i2cdetect' is a command from 'i2c-tools' package, which comes
with Chrom* OS image and is available from inside chroot.
TestFail: if i2c-dev can't be enabled.
args = ['i2cdetect', '-l']
out, _ = runInSubprocess(args)
if not out:'i2c-dev disabled. Enabling it with modprobe')
out, _ = runInSubprocess(['modprobe', 'i2c-dev'])
if out:
raise error.TestFail('Error enable i2c-dev: %s' % out)
out, _ = runInSubprocess(args)'i2c-dev ready to go:\n%s', out)
def computeTimeElapsed(end, start):
"""Computes time difference in microseconds.
end: a datetime.datetime() object, end timestamp.
start: a datetime.datetime() object, start timestamp.
usec: an int, difference between end and start in microseconds.
t = end - start
usec = 1000000 * t.seconds + t.microseconds'Elapsed time = %d usec', usec)
return usec