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#
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#
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# Copyright (C) 2006, 2007, 2010, 2011 Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""Utility functions for manipulating /etc/hosts.
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"""
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from cStringIO import StringIO
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from ganeti import pathutils
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from ganeti.utils import algo
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from ganeti.utils import io
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def SetEtcHostsEntry(file_name, ip, hostname, aliases):
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  """Sets the name of an IP address and hostname in /etc/hosts.
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  @type file_name: str
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  @param file_name: path to the file to modify (usually C{/etc/hosts})
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  @type ip: str
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  @param ip: the IP address
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  @type hostname: str
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  @param hostname: the hostname to be added
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  @type aliases: list
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  @param aliases: the list of aliases to add for the hostname
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  """
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  # Ensure aliases are unique
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  names = algo.UniqueSequence([hostname] + aliases)
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  out = StringIO()
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  def _write_entry(written):
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    if not written:
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      out.write("%s\t%s\n" % (ip, " ".join(names)))
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    return True
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  written = False
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  for line in io.ReadFile(file_name).splitlines(True):
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    fields = line.split()
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    if fields and not fields[0].startswith("#") and ip == fields[0]:
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      written = _write_entry(written)
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    else:
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      out.write(line)
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  _write_entry(written)
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  io.WriteFile(file_name, data=out.getvalue(), uid=0, gid=0, mode=0644,
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               keep_perms=io.KP_IF_EXISTS)
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def AddHostToEtcHosts(hostname, ip):
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  """Wrapper around SetEtcHostsEntry.
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  @type hostname: str
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  @param hostname: a hostname that will be resolved and added to
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      L{pathutils.ETC_HOSTS}
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  @type ip: str
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  @param ip: The ip address of the host
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  """
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  SetEtcHostsEntry(pathutils.ETC_HOSTS, ip, hostname, [hostname.split(".")[0]])
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def RemoveEtcHostsEntry(file_name, hostname):
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  """Removes a hostname from /etc/hosts.
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  IP addresses without names are removed from the file.
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  @type file_name: str
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  @param file_name: path to the file to modify (usually C{/etc/hosts})
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  @type hostname: str
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  @param hostname: the hostname to be removed
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  """
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  out = StringIO()
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  for line in io.ReadFile(file_name).splitlines(True):
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    fields = line.split()
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    if len(fields) > 1 and not fields[0].startswith("#"):
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      names = fields[1:]
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      if hostname in names:
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        while hostname in names:
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          names.remove(hostname)
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        if names:
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          out.write("%s %s\n" % (fields[0], " ".join(names)))
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        continue
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    out.write(line)
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  io.WriteFile(file_name, data=out.getvalue(), uid=0, gid=0, mode=0644,
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               keep_perms=io.KP_IF_EXISTS)
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def RemoveHostFromEtcHosts(hostname):
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  """Wrapper around RemoveEtcHostsEntry.
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  @type hostname: str
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  @param hostname: hostname that will be resolved and its
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      full and shot name will be removed from
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      L{pathutils.ETC_HOSTS}
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  """
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  RemoveEtcHostsEntry(pathutils.ETC_HOSTS, hostname)
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  RemoveEtcHostsEntry(pathutils.ETC_HOSTS, hostname.split(".")[0])