197 lines
6.4 KiB
Python
197 lines
6.4 KiB
Python
#
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# Copyright (C) 2012 Red Hat, Inc.
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#
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# This copyrighted material is made available to anyone wishing to use,
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# modify, copy, or redistribute it subject to the terms and conditions of
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# the GNU General Public License v.2, or (at your option) any later version.
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY expressed or implied, including the implied warranties of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
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# Public License for more details. You should have received a copy of the
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# GNU General Public License along with this program; if not, write to the
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# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA. Any Red Hat trademarks that are incorporated in the
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# source code or documentation are not subject to the GNU General Public
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# License and may only be used or replicated with the express permission of
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# Red Hat, Inc.
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#
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# Red Hat Author(s): Vratislav Podzimek <vpodzime@redhat.com>
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#
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"""
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Module facilitating the work with NTP servers and NTP daemon's configuration
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"""
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import re
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import os
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import tempfile
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import shutil
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from pyanaconda import iutil
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from pyanaconda.threads import threadMgr, AnacondaThread
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NTP_CONFIG_FILE = "/etc/chrony.conf"
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#example line:
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#server 0.fedora.pool.ntp.org iburst
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SRV_LINE_REGEXP = re.compile(r"^\s*server\s*([-a-zA-Z.0-9]+)\s*[a-zA-Z]+\s*$")
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class NTPconfigError(Exception):
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"""Exception class for NTP related problems"""
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pass
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def ntp_server_working(server):
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"""
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Runs rdate to try to connect to the $server (timeout may take some time).
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@return: True if the given server is reachable and working, False otherwise
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"""
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#FIXME: It would be nice to use execWithRedirect here, but it is not
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# thread-safe and hangs if this function is called from threads.
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# By using tee (and block-buffered pipes) it is also much slower.
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#we just need to know the exit status
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retc = os.system("rdate -p %s &>/dev/null" % server)
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return retc == 0
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def get_servers_from_config(conf_file_path=NTP_CONFIG_FILE,
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srv_regexp=SRV_LINE_REGEXP):
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"""
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Goes through the chronyd's configuration file looking for lines starting
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with 'server'.
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@return: servers found in the chronyd's configuration
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@rtype: list
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"""
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ret = list()
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try:
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with open(conf_file_path, "r") as conf_file:
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for line in conf_file:
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match = srv_regexp.match(line)
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if match:
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ret.append(match.group(1))
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except IOError as ioerr:
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msg = "Cannot open config file %s for reading (%s)" % (conf_file_path,
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ioerr.strerror)
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raise NTPconfigError(msg)
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return ret
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def save_servers_to_config(servers, conf_file_path=NTP_CONFIG_FILE,
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srv_regexp=SRV_LINE_REGEXP, out_file_path=None):
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"""
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Replaces the servers defined in the chronyd's configuration file with
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the given ones. If the out_file is not None, then it is used for the
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resulting config.
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@type servers: iterable
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@param out_file_path: path to the file used for the resulting config
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"""
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try:
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old_conf_file = open(conf_file_path, "r")
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except IOError as ioerr:
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msg = "Cannot open config file %s for reading (%s)" % (conf_file_path,
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ioerr.strerror)
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raise NTPconfigError(msg)
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try:
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if out_file_path:
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new_conf_file = open(out_file_path, "w")
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else:
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(fildes, temp_path) = tempfile.mkstemp()
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new_conf_file = os.fdopen(fildes, "w")
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except IOError as ioerr:
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if out_file_path:
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msg = "Cannot open new config file %s "\
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"for writing (%s)" % (out_file_path, ioerr.strerror)
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else:
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msg = "Cannot open temporary file %s "\
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"for writing (%s)" % (temp_path, ioerr.strerror)
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raise NTPconfigError(msg)
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heading = "# These servers were defined in the installation:\n"
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#write info about the origin of the following lines
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new_conf_file.write(heading)
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#write new servers
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for server in servers:
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new_conf_file.write("server " + server + " iburst\n")
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#copy non-server lines from the old config and skip our heading
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for line in old_conf_file:
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if not srv_regexp.match(line) and line != heading:
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new_conf_file.write(line)
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old_conf_file.close()
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new_conf_file.close()
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if not out_file_path:
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try:
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stat = os.stat(conf_file_path)
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shutil.move(temp_path, conf_file_path)
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os.chmod(conf_file_path, stat.st_mode)
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except OSError as oserr:
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msg = "Cannot replace the old config with "\
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"the new one (%s)" % (oserr.strerror)
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raise NTPconfigError(msg)
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def one_time_sync(server, callback=None):
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"""
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Synchronize the system time with a given NTP server. Note that this
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function is blocking and will not return until the time gets synced or
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querying server fails (may take some time before timeouting).
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@param server: NTP server
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@param callback: callback function to run after sync or failure
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@type callback: a function taking one boolean argument (success)
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@return: True if the sync was successful, False otherwise
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"""
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ret = iutil.execWithRedirect("rdate", ["-s", server], stdout="/dev/tty5",
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stderr="/dev/tty5")
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success = ret == 0
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if callback is not None:
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callback(success)
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return success
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def one_time_sync_async(server, callback=None):
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"""
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Asynchronously synchronize the system time with a given NTP server. This
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function is non-blocking it starts a new thread for synchronization and
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returns. Use callback argument to specify the function called when the
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new thread finishes if needed.
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@param server: NTP server
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@param callback: callback function to run after sync or failure
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@type callback: a function taking one boolean argument (success)
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"""
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thread_name = "AnaSyncTime_%s" % server
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if threadMgr.get(thread_name):
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#syncing with the same server running
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return
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threadMgr.add(AnacondaThread(name=thread_name, target=one_time_sync,
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args=(server, callback)))
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