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