<?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_owner_uid</refname> <refpurpose>Determine session, service or owner of a session of a specific PID</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_owner_uid</function></funcdef> <paramdef>pid_t <parameter>pid</parameter></paramdef> <paramdef>uid_t* <parameter>uid</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 unit (i.e. system service) identifier of a process identified by the specified process identifier. The unit name is a short string, suitable for usage in file system paths. Note that not all processes are part of a unit/service (e.g. user processes, or kernel threads). For processes not being part of a systemd unit/system service 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_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>If the <literal>pid</literal> parameter of any of these functions is passed as 0 the operation is executed for the calling 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_pid()</function>, and <function>sd_pid_get_owner_uid()</function> interfaces are available as shared library, which can be compiled and linked to with the <literal>libsystemd-login</literal> <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> </para> </refsect1> </refentry>