u-boot/test/py/u_boot_spawn.py
Paul Burton b8c455500a test/py: Use range() rather than xrange()
In python 3.x the xrange() function has been removed, and range()
returns an iterator much like Python 2.x's xrange(). Simply use range()
in place of xrange() in order to work on both python 2.x & 3.x. This
will mean a small cost on python 2.x since range() will return a list
there rather than an iterator, but the cost should be negligible.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
2018-07-10 14:50:50 -06:00

212 lines
6.3 KiB
Python

# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2015-2016, NVIDIA CORPORATION. All rights reserved.
# Logic to spawn a sub-process and interact with its stdio.
import os
import re
import pty
import signal
import select
import time
class Timeout(Exception):
"""An exception sub-class that indicates that a timeout occurred."""
pass
class Spawn(object):
"""Represents the stdio of a freshly created sub-process. Commands may be
sent to the process, and responses waited for.
Members:
output: accumulated output from expect()
"""
def __init__(self, args, cwd=None):
"""Spawn (fork/exec) the sub-process.
Args:
args: array of processs arguments. argv[0] is the command to
execute.
cwd: the directory to run the process in, or None for no change.
Returns:
Nothing.
"""
self.waited = False
self.buf = ''
self.output = ''
self.logfile_read = None
self.before = ''
self.after = ''
self.timeout = None
# http://stackoverflow.com/questions/7857352/python-regex-to-match-vt100-escape-sequences
# Note that re.I doesn't seem to work with this regex (or perhaps the
# version of Python in Ubuntu 14.04), hence the inclusion of a-z inside
# [] instead.
self.re_vt100 = re.compile('(\x1b\[|\x9b)[^@-_a-z]*[@-_a-z]|\x1b[@-_a-z]')
(self.pid, self.fd) = pty.fork()
if self.pid == 0:
try:
# For some reason, SIGHUP is set to SIG_IGN at this point when
# run under "go" (www.go.cd). Perhaps this happens under any
# background (non-interactive) system?
signal.signal(signal.SIGHUP, signal.SIG_DFL)
if cwd:
os.chdir(cwd)
os.execvp(args[0], args)
except:
print('CHILD EXECEPTION:')
import traceback
traceback.print_exc()
finally:
os._exit(255)
try:
self.poll = select.poll()
self.poll.register(self.fd, select.POLLIN | select.POLLPRI | select.POLLERR | select.POLLHUP | select.POLLNVAL)
except:
self.close()
raise
def kill(self, sig):
"""Send unix signal "sig" to the child process.
Args:
sig: The signal number to send.
Returns:
Nothing.
"""
os.kill(self.pid, sig)
def isalive(self):
"""Determine whether the child process is still running.
Args:
None.
Returns:
Boolean indicating whether process is alive.
"""
if self.waited:
return False
w = os.waitpid(self.pid, os.WNOHANG)
if w[0] == 0:
return True
self.waited = True
return False
def send(self, data):
"""Send data to the sub-process's stdin.
Args:
data: The data to send to the process.
Returns:
Nothing.
"""
os.write(self.fd, data)
def expect(self, patterns):
"""Wait for the sub-process to emit specific data.
This function waits for the process to emit one pattern from the
supplied list of patterns, or for a timeout to occur.
Args:
patterns: A list of strings or regex objects that we expect to
see in the sub-process' stdout.
Returns:
The index within the patterns array of the pattern the process
emitted.
Notable exceptions:
Timeout, if the process did not emit any of the patterns within
the expected time.
"""
for pi in range(len(patterns)):
if type(patterns[pi]) == type(''):
patterns[pi] = re.compile(patterns[pi])
tstart_s = time.time()
try:
while True:
earliest_m = None
earliest_pi = None
for pi in range(len(patterns)):
pattern = patterns[pi]
m = pattern.search(self.buf)
if not m:
continue
if earliest_m and m.start() >= earliest_m.start():
continue
earliest_m = m
earliest_pi = pi
if earliest_m:
pos = earliest_m.start()
posafter = earliest_m.end()
self.before = self.buf[:pos]
self.after = self.buf[pos:posafter]
self.output += self.buf[:posafter]
self.buf = self.buf[posafter:]
return earliest_pi
tnow_s = time.time()
if self.timeout:
tdelta_ms = (tnow_s - tstart_s) * 1000
poll_maxwait = self.timeout - tdelta_ms
if tdelta_ms > self.timeout:
raise Timeout()
else:
poll_maxwait = None
events = self.poll.poll(poll_maxwait)
if not events:
raise Timeout()
c = os.read(self.fd, 1024)
if not c:
raise EOFError()
if self.logfile_read:
self.logfile_read.write(c)
self.buf += c
# count=0 is supposed to be the default, which indicates
# unlimited substitutions, but in practice the version of
# Python in Ubuntu 14.04 appears to default to count=2!
self.buf = self.re_vt100.sub('', self.buf, count=1000000)
finally:
if self.logfile_read:
self.logfile_read.flush()
def close(self):
"""Close the stdio connection to the sub-process.
This also waits a reasonable time for the sub-process to stop running.
Args:
None.
Returns:
Nothing.
"""
os.close(self.fd)
for i in range(100):
if not self.isalive():
break
time.sleep(0.1)
def get_expect_output(self):
"""Return the output read by expect()
Returns:
The output processed by expect(), as a string.
"""
return self.output