systemd/man/sd_pid_get_session.xml
Jan Engelhardt 3b3d7d069d doc: balance C indirections in function prototypes
Shift the asterisks in the documentation's prototypes such that they
are consistent among each other. Use the right side to match what is
used in source code.

Addendum to commit v209~82.
2014-05-07 20:13:27 -04:00

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<?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 2010 Lennart Poettering
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="sd_pid_get_session" conditional='HAVE_PAM'>
<refentryinfo>
<title>sd_pid_get_session</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>sd_pid_get_session</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_pid_get_session</refname>
<refname>sd_pid_get_unit</refname>
<refname>sd_pid_get_user_unit</refname>
<refname>sd_pid_get_owner_uid</refname>
<refname>sd_pid_get_machine_name</refname>
<refname>sd_pid_get_slice</refname>
<refname>sd_peer_get_session</refname>
<refname>sd_peer_get_unit</refname>
<refname>sd_peer_get_user_unit</refname>
<refname>sd_peer_get_owner_uid</refname>
<refname>sd_peer_get_machine_name</refname>
<refname>sd_peer_get_slice</refname>
<refpurpose>Determine session, service, owner of a
session, container/VM or slice of a specific
PID or socket peer</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-login.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_pid_get_session</function></funcdef>
<paramdef>pid_t <parameter>pid</parameter></paramdef>
<paramdef>char **<parameter>session</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_pid_get_unit</function></funcdef>
<paramdef>pid_t <parameter>pid</parameter></paramdef>
<paramdef>char **<parameter>unit</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_pid_get_user_unit</function></funcdef>
<paramdef>pid_t <parameter>pid</parameter></paramdef>
<paramdef>char **<parameter>unit</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_pid_get_owner_uid</function></funcdef>
<paramdef>pid_t <parameter>pid</parameter></paramdef>
<paramdef>uid_t *<parameter>uid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_pid_get_machine_name</function></funcdef>
<paramdef>pid_t <parameter>pid</parameter></paramdef>
<paramdef>char **<parameter>name</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_pid_get_slice</function></funcdef>
<paramdef>pid_t <parameter>pid</parameter></paramdef>
<paramdef>char **<parameter>slice</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_peer_get_session</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>char **<parameter>session</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_peer_get_unit</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>char **<parameter>unit</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_peer_get_user_unit</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>char **<parameter>unit</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_peer_get_owner_uid</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>uid_t *<parameter>uid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_peer_get_machine_name</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>char **<parameter>name</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_peer_get_slice</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>char **<parameter>slice</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_pid_get_session()</function> may be
used to determine the login session identifier of a
process identified by the specified process
identifier. The session identifier is a short string,
suitable for usage in file system paths. Note that not
all processes are part of a login session (e.g. system
service processes, user processes that are shared
between multiple sessions of the same user, or kernel
threads). For processes not being part of a login
session this function will fail. The returned string
needs to be freed with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_pid_get_unit()</function> may be
used to determine the systemd system unit (i.e. system
service) identifier of a process identified by the
specified PID. The unit name is a short string,
suitable for usage in file system paths. Note that not
all processes are part of a system unit/service
(e.g. user processes, or kernel threads). For
processes not being part of a systemd system unit this
function will fail. (More specifically: this call will
not work for processes that are part of user units,
use <function>sd_pid_get_user_unit()</function> for
that.) The returned string needs to be freed with the
libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_pid_get_user_unit()</function> may
be used to determine the systemd user unit (i.e. user
service) identifier of a process identified by the
specified PID. This is similar to
<function>sd_pid_get_unit()</function> but applies to
user units instead of system units.</para>
<para><function>sd_pid_get_owner_uid()</function> may
be used to determine the Unix user identifier of the
owner of the session of a process identified the
specified PID. Note that this function will succeed
for user processes which are shared between multiple
login sessions of the same user, where
<function>sd_pid_get_session()</function> will
fail. For processes not being part of a login session
and not being a shared process of a user this function
will fail.</para>
<para><function>sd_pid_get_machine_name()</function>
may be used to determine the name of the VM or
container is a member of. The machine name is a short
string, suitable for usage in file system paths. The
returned string needs to be freed with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_pid_get_slice()</function> may be
used to determine the slice unit the process is a
member of. See
<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for details about slices. The returned string needs to
be freed with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para>If the <varname>pid</varname> parameter of any
of these functions is passed as 0, the operation is
executed for the calling process.</para>
<para>The <function>sd_peer_get_session()</function>,
<function>sd_peer_get_unit()</function>,
<function>sd_peer_get_user_unit()</function>,
<function>sd_peer_get_owner_uid()</function>,
<function>sd_peer_get_machine_name()</function> and
<function>sd_peer_get_slice()</function> calls operate
similar to their PID counterparts, but operate on a
connected AF_UNIX socket and retrieve information
about the connected peer process.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>On success, these calls return 0 or a positive
integer. On failure, these calls return a negative
errno-style error code.</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>The <function>sd_pid_get_session()</function>,
<function>sd_pid_get_unit()</function>,
<function>sd_pid_get_user_unit()</function>,
<function>sd_pid_get_owner_uid()</function>,
<function>sd_pid_get_machine_name()</function>,
<function>sd_pid_get_slice()</function>,
<function>sd_peer_get_session()</function>,
<function>sd_peer_get_unit()</function>,
<function>sd_peer_get_user_unit()</function>,
<function>sd_peer_get_owner_uid()</function>,
<function>sd_peer_get_machine_name()</function> and
<function>sd_peer_get_slice()</function> interfaces are
available as a shared library, which can be compiled
and linked to with the
<constant>libsystemd</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
file.</para>
<para>Note that the login session identifier as
returned by <function>sd_pid_get_session()</function>
is completely unrelated to the process session
identifier as returned by
<citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_session_is_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>