--- /dev/null
+<?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">
+
+<!--
+ 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_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 <systemd/sd-login.h></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
+ -ENODATA. 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 -ENODATA. (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 -ENODATA.</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 -ENODATA.</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>
~ianmdlvl / elogind.git / blobdiff