X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=man%2Fsd_pid_get_session.xml;h=5bc5efdac10808c44faa7074eb14300b54acc877;hb=d04b238170998e0cbcc86db0f8ae66c3ee4a14d6;hp=933138da16e90f796870ade5a81d429299ee482b;hpb=3b3d7d069d10d53336dbada1c67f739e3492b218;p=elogind.git

diff --git a/man/sd_pid_get_session.xml b/man/sd_pid_get_session.xml
index 933138da1..5bc5efdac 100644
--- a/man/sd_pid_get_session.xml
+++ b/man/sd_pid_get_session.xml
@@ -1,6 +1,6 @@
-<?xml version='1.0'?> <!--*-nxml-*-->
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
-        "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
 
 <!--
   This file is part of systemd.
@@ -23,249 +23,337 @@
 
 <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>
+  <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_pid_get_user_slice</refname>
+    <refname>sd_pid_get_cgroup</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>
+    <refname>sd_peer_get_user_slice</refname>
+    <refname>sd_peer_get_cgroup</refname>
+    <refpurpose>Determine session, unit, 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_pid_get_user_slice</function></funcdef>
+        <paramdef>pid_t <parameter>pid</parameter></paramdef>
+        <paramdef>char **<parameter>slice</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_pid_get_cgroup</function></funcdef>
+        <paramdef>pid_t <parameter>pid</parameter></paramdef>
+        <paramdef>char **<parameter>cgroup</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>
+
+      <funcprototype>
+        <funcdef>int <function>sd_peer_get_user_slice</function></funcdef>
+        <paramdef>int <parameter>fd</parameter></paramdef>
+        <paramdef>char **<parameter>slice</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_peer_get_cgroup</function></funcdef>
+        <paramdef>int <parameter>fd</parameter></paramdef>
+        <paramdef>char **<parameter>cgroup</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 with
+    <constant>-ENODATA</constant>. The returned string needs to be freed with the libc
+    <citerefentry
+    project='man-pages'><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 or scope
+    unit) 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 with <constant>-ENODATA</constant>. (More specifically, this call will not
+    work for kernel threads.) The returned string needs to be freed
+    with the libc <citerefentry
+    project='man-pages'><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 or scope unit)
+    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 UID (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, whereas
+    <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 with <constant>-ENODATA</constant>.</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
+    project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    call after use. For processes not part of a VM or containers, this
+    function fails with <constant>-ENODATA</constant>.</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 project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    call after use.</para>
+
+    <para>Similarly, <function>sd_pid_get_user_slice()</function>
+    returns the user slice (as managed by the user's systemd instance)
+    of a process.</para>
+
+    <para><function>sd_pid_get_cgroup()</function> returns the control
+    group path of the specified process, relative to the root of the
+    hierarchy. Returns the path without trailing slash, except for
+    processes located in the root control group, where "/" is
+    returned. To find the actual control group path in the file system,
+    the returned path needs to be prefixed with
+    <filename>/sys/fs/cgroup/</filename> (if the unified control group
+    setup is used), or
+    <filename>/sys/fs/cgroup/<replaceable>HIERARCHY</replaceable>/</filename>
+    (if the legacy multi-hierarchy control group setup is used).</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>,
+    <function>sd_peer_get_slice()</function>,
+    <function>sd_peer_get_user_slice()</function> and
+    <function>sd_peer_get_cgroup()</function> calls operate similar to
+    their PID counterparts, but operate on a connected AF_UNIX socket
+    and retrieve information about the connected peer process. Note
+    that these fields are retrieved via <filename>/proc</filename>,
+    and hence are not suitable for authorization purposes, as they are
+    subject to races.</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>Errors</title>
+
+    <para>Returned errors may indicate the following problems:</para>
+
+    <variablelist>
+
+      <varlistentry>
+        <term><constant>-ESRCH</constant></term>
+
+        <listitem><para>The specified PID does not refer to a running
+        process.</para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><constant>-BADF</constant></term>
+
+        <listitem><para>The specified socket file descriptor was
+        invalid.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><constant>-ENODATA</constant></term>
+
+        <listitem><para>The given field is not specified for the described
+        process or peer.</para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><constant>-EINVAL</constant></term>
+
+        <listitem><para>An input parameter was invalid (out of range,
+        or NULL, where that is not accepted).</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><constant>-ENOMEM</constant></term>
+
+        <listitem><para>Memory allocation failed.</para></listitem>
+      </varlistentry>
+    </variablelist>
+  </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_pid_get_user_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>,
+    <function>sd_peer_get_slice()</function> and
+    <function>sd_peer_get_user_slice()</function> interfaces are
+    available as a shared library, which can be compiled and linked to
+    with the <constant>libelogind</constant> <citerefentry
+    project='die-net'><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>,
+      <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+    </para>
+  </refsect1>
 
 </refentry>