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ce737f46cd
test-login.c is largely rewritten to use _cleanup_ and give more meaningful
messages (function names are used instead of creative terms like "active
session", so that when something unexpected is returned, it's much easier to
see what function is responsible).
The monitoring part is only activated if '-m' is passed on the command line.
It runs against the information from /run/systemd/ in the live system, but that
should be OK: logind/sd-login interface is supposed to be stable and both
backwards and forwards compatible.
If not running in a login session, some tests are skipped.
Those two changes together mean that it's possible to run test-login in the
test suite.
Tests for sd_pid_get_{unit,user_unit,slice} are added.
360 lines
15 KiB
XML
360 lines
15 KiB
XML
<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="sd_pid_get_session" conditional='HAVE_PAM'>
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<refentryinfo>
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<title>sd_pid_get_session</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>sd_pid_get_session</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>sd_pid_get_session</refname>
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<refname>sd_pid_get_unit</refname>
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<refname>sd_pid_get_user_unit</refname>
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<refname>sd_pid_get_owner_uid</refname>
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<refname>sd_pid_get_machine_name</refname>
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<refname>sd_pid_get_slice</refname>
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<refname>sd_pid_get_user_slice</refname>
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<refname>sd_pid_get_cgroup</refname>
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<refname>sd_peer_get_session</refname>
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<refname>sd_peer_get_unit</refname>
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<refname>sd_peer_get_user_unit</refname>
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<refname>sd_peer_get_owner_uid</refname>
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<refname>sd_peer_get_machine_name</refname>
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<refname>sd_peer_get_slice</refname>
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<refname>sd_peer_get_user_slice</refname>
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<refname>sd_peer_get_cgroup</refname>
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<refpurpose>Determine session, unit, owner of a session,
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container/VM or slice of a specific PID or socket
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peer</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>int <function>sd_pid_get_session</function></funcdef>
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<paramdef>pid_t <parameter>pid</parameter></paramdef>
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<paramdef>char **<parameter>session</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_pid_get_unit</function></funcdef>
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<paramdef>pid_t <parameter>pid</parameter></paramdef>
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<paramdef>char **<parameter>unit</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_pid_get_user_unit</function></funcdef>
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<paramdef>pid_t <parameter>pid</parameter></paramdef>
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<paramdef>char **<parameter>unit</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_pid_get_owner_uid</function></funcdef>
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<paramdef>pid_t <parameter>pid</parameter></paramdef>
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<paramdef>uid_t *<parameter>uid</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_pid_get_machine_name</function></funcdef>
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<paramdef>pid_t <parameter>pid</parameter></paramdef>
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<paramdef>char **<parameter>name</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_pid_get_slice</function></funcdef>
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<paramdef>pid_t <parameter>pid</parameter></paramdef>
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<paramdef>char **<parameter>slice</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_pid_get_user_slice</function></funcdef>
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<paramdef>pid_t <parameter>pid</parameter></paramdef>
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<paramdef>char **<parameter>slice</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_pid_get_cgroup</function></funcdef>
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<paramdef>pid_t <parameter>pid</parameter></paramdef>
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<paramdef>char **<parameter>cgroup</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_peer_get_session</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>char **<parameter>session</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_peer_get_unit</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>char **<parameter>unit</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_peer_get_user_unit</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>char **<parameter>unit</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_peer_get_owner_uid</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>uid_t *<parameter>uid</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_peer_get_machine_name</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>char **<parameter>name</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_peer_get_slice</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>char **<parameter>slice</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_peer_get_user_slice</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>char **<parameter>slice</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_peer_get_cgroup</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>char **<parameter>cgroup</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><function>sd_pid_get_session()</function> may be used to
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determine the login session identifier of a process identified by
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the specified process identifier. The session identifier is a
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short string, suitable for usage in file system paths. Note that
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not all processes are part of a login session (e.g. system service
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processes, user processes that are shared between multiple
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sessions of the same user, or kernel threads). For processes not
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being part of a login session, this function will fail with
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<constant>-ENODATA</constant>. The returned string needs to be freed with the libc
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<citerefentry
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project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para><function>sd_pid_get_unit()</function> may be used to
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determine the systemd system unit (i.e. system service or scope
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unit) identifier of a process identified by the specified PID. The
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unit name is a short string, suitable for usage in file system
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paths. Note that not all processes are part of a system
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unit/service (e.g. user processes, or kernel threads). For
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processes not being part of a systemd system unit, this function
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will fail with <constant>-ENODATA</constant>. (More specifically, this call will not
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work for kernel threads.) The returned string needs to be freed
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with the libc <citerefentry
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project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para><function>sd_pid_get_user_unit()</function> may be used to
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determine the systemd user unit (i.e. user service or scope unit)
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identifier of a process identified by the specified PID. This is
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similar to <function>sd_pid_get_unit()</function>, but applies to
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user units instead of system units.</para>
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<para><function>sd_pid_get_owner_uid()</function> may be used to
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determine the Unix UID (user identifier) of the owner of the
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session of a process identified the specified PID. Note that this
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function will succeed for user processes which are shared between
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multiple login sessions of the same user, whereas
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<function>sd_pid_get_session()</function> will fail. For processes
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not being part of a login session and not being a shared process
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of a user, this function will fail with <constant>-ENODATA</constant>.</para>
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<para><function>sd_pid_get_machine_name()</function> may be used
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to determine the name of the VM or container is a member of. The
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machine name is a short string, suitable for usage in file system
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paths. The returned string needs to be freed with the libc
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<citerefentry
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project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use. For processes not part of a VM or containers, this
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function fails with <constant>-ENODATA</constant>.</para>
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<para><function>sd_pid_get_slice()</function> may be used to
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determine the slice unit the process is a member of. See
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<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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for details about slices. The returned string needs to be freed
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with the libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para>Similarly, <function>sd_pid_get_user_slice()</function>
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returns the user slice (as managed by the user's systemd instance)
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of a process.</para>
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<para><function>sd_pid_get_cgroup()</function> returns the control
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group path of the specified process, relative to the root of the
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hierarchy. Returns the path without trailing slash, except for
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processes located in the root control group, where "/" is
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returned. To find the actual control group path in the file system,
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the returned path needs to be prefixed with
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<filename>/sys/fs/cgroup/</filename> (if the unified control group
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setup is used), or
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<filename>/sys/fs/cgroup/<replaceable>HIERARCHY</replaceable>/</filename>
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(if the legacy multi-hierarchy control group setup is used).</para>
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<para>If the <varname>pid</varname> parameter of any of these
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functions is passed as 0, the operation is executed for the
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calling process.</para>
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<para>The <function>sd_peer_get_session()</function>,
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<function>sd_peer_get_unit()</function>,
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<function>sd_peer_get_user_unit()</function>,
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<function>sd_peer_get_owner_uid()</function>,
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<function>sd_peer_get_machine_name()</function>,
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<function>sd_peer_get_slice()</function>,
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<function>sd_peer_get_user_slice()</function> and
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<function>sd_peer_get_cgroup()</function> calls operate similar to
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their PID counterparts, but operate on a connected AF_UNIX socket
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and retrieve information about the connected peer process. Note
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that these fields are retrieved via <filename>/proc</filename>,
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and hence are not suitable for authorization purposes, as they are
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subject to races.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para>On success, these calls return 0 or a positive integer. On
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failure, these calls return a negative errno-style error
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code.</para>
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</refsect1>
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<refsect1>
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<title>Errors</title>
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<para>Returned errors may indicate the following problems:</para>
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<variablelist>
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<varlistentry>
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<term><constant>-ESRCH</constant></term>
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<listitem><para>The specified PID does not refer to a running
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process.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-BADF</constant></term>
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<listitem><para>The specified socket file descriptor was
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invalid.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ENODATA</constant></term>
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<listitem><para>The given field is not specified for the described
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process or peer.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-EINVAL</constant></term>
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<listitem><para>An input parameter was invalid (out of range,
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or NULL, where that is not accepted).</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ENOMEM</constant></term>
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<listitem><para>Memory allocation failed.</para></listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para>The <function>sd_pid_get_session()</function>,
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<function>sd_pid_get_unit()</function>,
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<function>sd_pid_get_user_unit()</function>,
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<function>sd_pid_get_owner_uid()</function>,
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<function>sd_pid_get_machine_name()</function>,
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<function>sd_pid_get_slice()</function>,
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<function>sd_pid_get_user_slice()</function>,
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<function>sd_peer_get_session()</function>,
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<function>sd_peer_get_unit()</function>,
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<function>sd_peer_get_user_unit()</function>,
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<function>sd_peer_get_owner_uid()</function>,
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<function>sd_peer_get_machine_name()</function>,
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<function>sd_peer_get_slice()</function> and
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<function>sd_peer_get_user_slice()</function> interfaces are
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available as a shared library, which can be compiled and linked to
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with the <constant>libsystemd</constant> <citerefentry
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project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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file.</para>
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<para>Note that the login session identifier as
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returned by <function>sd_pid_get_session()</function>
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is completely unrelated to the process session
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identifier as returned by
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<citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>.</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_session_is_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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