[lxc-devel] [PATCH] add lxc-unshare man page, and make 'lxc-unshare -h' work.
Stéphane Graber
stgraber at ubuntu.com
Fri Feb 8 23:36:28 UTC 2013
On 02/08/2013 06:32 PM, Serge Hallyn wrote:
>
> Also fix some tabs-as-spaces in lxc_unshare.c itself.
> lxc-unshare: run usage() on '-h'
>
> Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
Acked-by: Stéphane Graber <stgraber at ubuntu.com>
> ---
> configure.ac | 1 +
> doc/Makefile.am | 1 +
> doc/lxc-unshare.sgml.in | 161 ++++++++++++++++++++++++++++++++++++++++++++++++
> src/lxc/lxc_unshare.c | 16 ++---
> 4 files changed, 172 insertions(+), 7 deletions(-)
> create mode 100644 doc/lxc-unshare.sgml.in
>
> diff --git a/configure.ac b/configure.ac
> index 6402024..eb4b714 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -326,6 +326,7 @@ AC_CONFIG_FILES([
> doc/common_options.sgml
> doc/see_also.sgml
> doc/legacy/lxc-ls.sgml
> + doc/lxc-unshare.sgml
>
> doc/rootfs/Makefile
>
> diff --git a/doc/Makefile.am b/doc/Makefile.am
> index e54a087..750398c 100644
> --- a/doc/Makefile.am
> +++ b/doc/Makefile.am
> @@ -18,6 +18,7 @@ man_MANS = \
> lxc-console.1 \
> lxc-freeze.1 \
> lxc-unfreeze.1 \
> + lxc-unshare.1 \
> lxc-monitor.1 \
> lxc-wait.1 \
> lxc-ps.1 \
> diff --git a/doc/lxc-unshare.sgml.in b/doc/lxc-unshare.sgml.in
> new file mode 100644
> index 0000000..4132d4c
> --- /dev/null
> +++ b/doc/lxc-unshare.sgml.in
> @@ -0,0 +1,161 @@
> +<!--
> +
> +lxc: linux Container library
> +
> +(C) Copyright IBM Corp. 2007, 2008
> +
> +Authors:
> +Daniel Lezcano <dlezcano at fr.ibm.com>
> +Serge Hallyn <serge.hallyn at ubuntu.com>
> +
> +This library 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.
> +
> +This library 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 this library; if not, write to the Free Software
> +Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> +
> +-->
> +
> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
> +
> +<!ENTITY commonoptions SYSTEM "@builddir@/common_options.sgml">
> +<!ENTITY seealso SYSTEM "@builddir@/see_also.sgml">
> +]>
> +
> +<refentry>
> +
> + <docinfo><date>@LXC_GENERATE_DATE@</date></docinfo>
> +
> + <refmeta>
> + <refentrytitle>lxc-unshare</refentrytitle>
> + <manvolnum>1</manvolnum>
> + </refmeta>
> +
> + <refnamediv>
> + <refname>lxc-unshare</refname>
> +
> + <refpurpose>
> + Run a task in a new set of namespaces.
> + </refpurpose>
> + </refnamediv>
> +
> + <refsynopsisdiv>
> + <cmdsynopsis>
> + <command>lxc-clone</command>
> + <arg choice="req">-s <replaceable>namespaces</replaceable></arg>
> + <arg choice="req">-u <replaceable>user</replaceable></arg>
> + <arg choice="req">command</arg>
> + </cmdsynopsis>
> + </refsynopsisdiv>
> +
> + <refsect1>
> + <title>Description</title>
> +
> + <para>
> + <command>lxc-unshare</command> can be used to run a task in a cloned set
> + of namespaces. This command is mainly provided for testing purposes.
> + Despite its name, it always uses clone rather than unshare to create
> + the new task with fresh namespaces. Apart from testing kernel
> + regressions this should make no difference.
> + </para>
> +
> + </refsect1>
> +
> + <refsect1>
> +
> + <title>Options</title>
> +
> + <variablelist>
> +
> + <varlistentry>
> + <term>
> + <option>-s <replaceable>namespaces</replaceable></option>
> + </term>
> + <listitem>
> + <para>
> + Specify the namespaces to attach to, as a pipe-separated list,
> + e.g. <replaceable>NETWORK|IPC</replaceable>. Allowed values are
> + <replaceable>MOUNT</replaceable>, <replaceable>PID</replaceable>,
> + <replaceable>UTSNAME</replaceable>, <replaceable>IPC</replaceable>,
> + <replaceable>USER </replaceable> and
> + <replaceable>NETWORK</replaceable>. This allows one to change
> + the context of the process to e.g. the network namespace of the
> + container while retaining the other namespaces as those of the
> + host.
> + </para>
> + </listitem>
> + </varlistentry>
> +
> + <varlistentry>
> + <term>
> + <option>-u <replaceable>user</replaceable></option>
> + </term>
> + <listitem>
> + <para>
> + Specify a user which the new task should become. This option is
> + only valid if a user namespace is unshared.
> + </para>
> + </listitem>
> + </varlistentry>
> +
> + </variablelist>
> +
> + </refsect1>
> +
> + <refsect1>
> + <title>Examples</title>
> + <para>
> + To spawn a new shell with its own UTS (hostname) namespace,
> + <programlisting>
> + lxc-clone -s UTSNAME /bin/bash
> + </programlisting>
> + If the hostname is changed in that shell, the change will not be
> + reflected on the host.
> + </para>
> + <para>
> + To spawn a shell in a new network, pid, and mount namespace,
> + <programlisting>
> + lxc-clone -s "NETWORK|PID|MOUNT" /bin/bash
> + </programlisting>
> + The resulting shell will have pid 1 and will see no network interfaces.
> + After re-mounting /proc in that shell,
> + <programlisting>
> + mount -t proc proc /proc
> + </programlisting>
> + ps output will show there are no other processes in the namespace.
> + </para>
> + </refsect1>
> +
> + &seealso;
> +
> + <refsect1>
> + <title>Author</title>
> + <para>Daniel Lezcano <email>daniel.lezcano at free.fr</email></para>
> + </refsect1>
> +
> +</refentry>
> +
> +<!-- Keep this comment at the end of the file
> +Local variables:
> +mode: sgml
> +sgml-omittag:t
> +sgml-shorttag:t
> +sgml-minimize-attributes:nil
> +sgml-always-quote-attributes:t
> +sgml-indent-step:2
> +sgml-indent-data:t
> +sgml-parent-document:nil
> +sgml-default-dtd-file:nil
> +sgml-exposed-tags:nil
> +sgml-local-catalogs:nil
> +sgml-local-ecat-files:nil
> +End:
> +-->
> diff --git a/src/lxc/lxc_unshare.c b/src/lxc/lxc_unshare.c
> index df91456..d92a96a 100644
> --- a/src/lxc/lxc_unshare.c
> +++ b/src/lxc/lxc_unshare.c
> @@ -125,11 +125,13 @@ int main(int argc, char *argv[])
> .flags = &flags,
> };
>
> - while ((opt = getopt(argc, argv, "s:u:")) != -1) {
> + while ((opt = getopt(argc, argv, "s:u:h")) != -1) {
> switch (opt) {
> case 's':
> namespaces = optarg;
> break;
> + case 'h':
> + usage(argv[0]);
> case 'u':
> uid = lookup_user(optarg);
> if (uid == -1)
> @@ -137,10 +139,10 @@ int main(int argc, char *argv[])
> }
> }
>
> - if (argv[optind] == NULL) {
> - ERROR("a command to execute in the new namespace is required");
> - return 1;
> - }
> + if (argv[optind] == NULL) {
> + ERROR("a command to execute in the new namespace is required");
> + return 1;
> + }
>
> args = &argv[optind];
>
> @@ -148,8 +150,8 @@ int main(int argc, char *argv[])
> if (ret)
> return ret;
>
> - ret = lxc_fill_namespace_flags(namespaces, &flags);
> - if (ret)
> + ret = lxc_fill_namespace_flags(namespaces, &flags);
> + if (ret)
> usage(argv[0]);
>
> if (!(flags & CLONE_NEWUSER) && uid != -1) {
>
--
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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