mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-09-11 23:33:26 +09:00
175 lines
4.8 KiB
Python
175 lines
4.8 KiB
Python
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# Copyright (c) 2015-2016, NVIDIA CORPORATION. All rights reserved.
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#
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# SPDX-License-Identifier: GPL-2.0
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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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'''
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def __init__(self, args):
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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 execute.
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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.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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(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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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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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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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 xrange(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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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 xrange(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() + 1
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self.before = self.buf[:pos]
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self.after = self.buf[pos:posafter]
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self.buf = self.buf[posafter:]
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return earliest_pi
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events = self.poll.poll(self.timeout)
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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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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 xrange(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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