systemd/man/nss-myhostname.xml
Zbigniew Jędrzejewski-Szmek 5aded36978 man: add a mapping for external manpages
It is annoying when we have dead links on fd.o.

Add project='man-pages|die-net|archlinux' to <citerefentry>-ies.

In generated html, add external links to
http://man7.org/linux/man-pages/man, http://linux.die.net/man/,
https://www.archlinux.org/.

By default, pages in sections 2 and 4 go to man7, since Michael
Kerrisk is the autorative source on kernel related stuff.

The rest of links goes to linux.die.net, because they have the
manpages.

Except for the pacman stuff, since it seems to be only available from
archlinux.org.

Poor gummiboot gets no link, because gummitboot(8) ain't to be found
on the net. According to common wisdom, that would mean that it does
not exist. But I have seen Kay using it, so I know it does, and
deserves to be found. Can somebody be nice and put it up somewhere?
2014-07-07 18:36:55 -04:00

134 lines
5.8 KiB
XML

<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2011 Lennart Poettering
Copyright 2013 Tom Gundersen
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="nss-myhostname" conditional='HAVE_MYHOSTNAME'>
<refentryinfo>
<title>nss-myhostname</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>nss-myhostname</refentrytitle>
<manvolnum>8</manvolnum>
</refmeta>
<refnamediv>
<refname>nss-myhostname</refname>
<refpurpose>Provide hostname resolution for the locally
configured system hostname.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<para><filename>nss-myhostname.la</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><command>nss-myhostname</command> is a plugin for the GNU Name Service Switch
(NSS) functionality of the GNU C Library (<command>glibc</command>)
providing hostname resolution for the locally configured system
hostname as returned by
<citerefentry><refentrytitle>gethostname</refentrytitle><manvolnum>2</manvolnum></citerefentry>.
Various software relies on an always-resolvable local hostname. When
using dynamic hostnames, this is usually achieved by patching
<filename>/etc/hosts</filename> at the same time as changing the host
name. This however is not ideal since it requires a writable
<filename>/etc</filename> file system and is fragile because the file
might be edited by the administrator at the same time. <command>nss-myhostname</command>
simply returns all locally configured public IP addresses, or, if none
are configured, the IPv4 address 127.0.0.2 (which is on the local
loopback) and the IPv6 address ::1 (which is the local host) for
whatever system hostname is configured locally. Patching
<filename>/etc/hosts</filename> is thus no longer necessary.</para>
<para>To activate the NSS modules, <option>myhostname</option>
has to be added to the line starting with "<varname>hosts:</varname>" in
<filename>/etc/nsswitch.conf</filename></para>
<para>It is recommended to put <option>myhostname</option>
last in the <filename>nsswitch.conf</filename> line to make
sure that this mapping is only used as fallback, and any DNS
or <filename>/etc/hosts</filename> based mapping takes precedence.</para>
</refsect1>
<refsect1>
<title>Example</title>
<programlisting># /etc/nsswitch.conf
passwd: compat
group: compat
shadow: compat
hosts: files dns <varname>myhostname</varname>
networks: files
protocols: db files
services: db files
ethers: db files
rpc: db files
netgroup: nis</programlisting>
<para>To test, use <command>glibc</command>'s <command>getent</command> tool:</para>
<programlisting>$ getent ahosts `hostname`
::1 STREAM omega
::1 DGRAM
::1 RAW
127.0.0.2 STREAM
127.0.0.2 DGRAM
127.0.0.2 RAW</programlisting>
<para>In this case the local hostname is <varname>omega</varname>.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>pam.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>pam.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry project='die-net'><refentrytitle>pam_loginuid</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>