129 lines
4.3 KiB
Python
129 lines
4.3 KiB
Python
# Copyright 2012 Locaweb.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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#
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# @author: Juliano Martinez, Locaweb.
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import fcntl
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import os
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import shlex
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import socket
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import struct
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import tempfile
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from eventlet.green import subprocess
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from eventlet import greenthread
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from neutron.common import utils
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from neutron.openstack.common import excutils
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from neutron.openstack.common import log as logging
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LOG = logging.getLogger(__name__)
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def create_process(cmd, root_helper=None, addl_env=None):
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"""Create a process object for the given command.
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The return value will be a tuple of the process object and the
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list of command arguments used to create it.
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"""
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if root_helper:
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cmd = shlex.split(root_helper) + cmd
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cmd = map(str, cmd)
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LOG.debug(_("Running command: %s"), cmd)
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env = os.environ.copy()
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if addl_env:
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env.update(addl_env)
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obj = utils.subprocess_popen(cmd, shell=False,
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stdin=subprocess.PIPE,
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stdout=subprocess.PIPE,
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stderr=subprocess.PIPE,
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env=env)
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return obj, cmd
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def execute(cmd, root_helper=None, process_input=None, addl_env=None,
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check_exit_code=True, return_stderr=False):
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try:
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obj, cmd = create_process(cmd, root_helper=root_helper,
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addl_env=addl_env)
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_stdout, _stderr = (process_input and
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obj.communicate(process_input) or
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obj.communicate())
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obj.stdin.close()
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m = _("\nCommand: %(cmd)s\nExit code: %(code)s\nStdout: %(stdout)r\n"
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"Stderr: %(stderr)r") % {'cmd': cmd, 'code': obj.returncode,
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'stdout': _stdout, 'stderr': _stderr}
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if obj.returncode:
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LOG.error(m)
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if check_exit_code:
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raise RuntimeError(m)
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else:
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LOG.debug(m)
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finally:
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# NOTE(termie): this appears to be necessary to let the subprocess
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# call clean something up in between calls, without
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# it two execute calls in a row hangs the second one
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greenthread.sleep(0)
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return return_stderr and (_stdout, _stderr) or _stdout
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def get_interface_mac(interface):
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DEVICE_NAME_LEN = 15
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MAC_START = 18
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MAC_END = 24
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s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
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info = fcntl.ioctl(s.fileno(), 0x8927,
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struct.pack('256s', interface[:DEVICE_NAME_LEN]))
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return ''.join(['%02x:' % ord(char)
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for char in info[MAC_START:MAC_END]])[:-1]
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def replace_file(file_name, data):
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"""Replaces the contents of file_name with data in a safe manner.
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First write to a temp file and then rename. Since POSIX renames are
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atomic, the file is unlikely to be corrupted by competing writes.
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We create the tempfile on the same device to ensure that it can be renamed.
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"""
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base_dir = os.path.dirname(os.path.abspath(file_name))
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tmp_file = tempfile.NamedTemporaryFile('w+', dir=base_dir, delete=False)
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tmp_file.write(data)
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tmp_file.close()
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os.chmod(tmp_file.name, 0o644)
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os.rename(tmp_file.name, file_name)
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def find_child_pids(pid):
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"""Retrieve a list of the pids of child processes of the given pid."""
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try:
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raw_pids = execute(['ps', '--ppid', pid, '-o', 'pid='])
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except RuntimeError as e:
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# Unexpected errors are the responsibility of the caller
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with excutils.save_and_reraise_exception() as ctxt:
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# Exception has already been logged by execute
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no_children_found = 'Exit code: 1' in str(e)
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if no_children_found:
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ctxt.reraise = False
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return []
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return [x.strip() for x in raw_pids.split('\n') if x.strip()]
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