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<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="sd_pid_get_owner_uid" conditional='HAVE_PAM'
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_pid_get_owner_uid</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_pid_get_owner_uid</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_pid_get_owner_uid</refname>
<refname>sd_pid_get_session</refname>
<refname>sd_pid_get_user_unit</refname>
<refname>sd_pid_get_unit</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_pidfd_get_owner_uid</refname>
<refname>sd_pidfd_get_session</refname>
<refname>sd_pidfd_get_user_unit</refname>
<refname>sd_pidfd_get_unit</refname>
<refname>sd_pidfd_get_machine_name</refname>
<refname>sd_pidfd_get_slice</refname>
<refname>sd_pidfd_get_user_slice</refname>
<refname>sd_pidfd_get_cgroup</refname>
<refname>sd_peer_get_owner_uid</refname>
<refname>sd_peer_get_session</refname>
<refname>sd_peer_get_user_unit</refname>
<refname>sd_peer_get_unit</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 the owner uid of the user unit or session,
or the session, user unit, system unit, container/VM or slice that
a specific PID or socket peer belongs to</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo>
<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_session</function></funcdef>
<paramdef>pid_t <parameter>pid</parameter></paramdef>
<paramdef>char **<parameter>session</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_unit</function></funcdef>
<paramdef>pid_t <parameter>pid</parameter></paramdef>
<paramdef>char **<parameter>unit</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_pidfd_get_owner_uid</function></funcdef>
<paramdef>int <parameter>pidfd</parameter></paramdef>
<paramdef>uid_t *<parameter>uid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_pidfd_get_session</function></funcdef>
<paramdef>int <parameter>pidfd</parameter></paramdef>
<paramdef>char **<parameter>session</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_pidfd_get_user_unit</function></funcdef>
<paramdef>int <parameter>pidfd</parameter></paramdef>
<paramdef>char **<parameter>unit</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_pidfd_get_unit</function></funcdef>
<paramdef>int <parameter>pidfd</parameter></paramdef>
<paramdef>char **<parameter>unit</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_pidfd_get_machine_name</function></funcdef>
<paramdef>int <parameter>pidfd</parameter></paramdef>
<paramdef>char **<parameter>name</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_pidfd_get_slice</function></funcdef>
<paramdef>int <parameter>pidfd</parameter></paramdef>
<paramdef>char **<parameter>slice</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_pidfd_get_user_slice</function></funcdef>
<paramdef>int <parameter>pidfd</parameter></paramdef>
<paramdef>char **<parameter>slice</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_pidfd_get_cgroup</function></funcdef>
<paramdef>int <parameter>pidfd</parameter></paramdef>
<paramdef>char **<parameter>cgroup</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_session</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>char **<parameter>session</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_unit</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>char **<parameter>unit</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_owner_uid()</function> may be used to
determine the Unix UID (user identifier) which owns the login
session or systemd user unit of a process identified by the
specified PID. For processes which are not part of a login session
and not managed by a user manager, this function will fail with
<constant>-ENODATA</constant>.</para>
<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. Please
note the login session may be limited to a stub process or two.
User processes may instead be started from their systemd user
manager, e.g. GUI applications started using DBus activation, as
well as service processes which are shared between multiple logins
of the same user. For processes which are not 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_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. The
unit name is a short string, suitable for usage in file system
paths. For processes which are not managed by a user manager, 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. 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_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 container, 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>.</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_pidfd_get_owner_uid()</function>,
<function>sd_pidfd_get_session()</function>,
<function>sd_pidfd_get_user_unit()</function>,
<function>sd_pidfd_get_unit()</function>,
<function>sd_pidfd_get_machine_name()</function>,
<function>sd_pidfd_get_slice()</function>,
<function>sd_pidfd_get_user_slice()</function> and
<function>sd_pidfd_get_cgroup()</function> calls operate similarly to their PID counterparts, but accept a
<constant>PIDFD</constant> instead of a <constant>PID</constant>, which means they are not subject to recycle
race conditions as the process is pinned by the file descriptor during the whole duration of the invocation.
Note that these require a kernel that supports <constant>PIDFD</constant>. A suitable file descriptor may be
acquired via
<citerefentry project='man-pages'><refentrytitle>pidfd_open</refentrytitle><manvolnum>2</manvolnum></citerefentry>.</para>
<para>The <function>sd_peer_get_owner_uid()</function>,
<function>sd_peer_get_session()</function>,
<function>sd_peer_get_user_unit()</function>,
<function>sd_peer_get_unit()</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 similarly to their PID counterparts, but accept a
connected <constant>AF_UNIX</constant> 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>
<refsect2>
<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>-EBADF</constant></term>
<listitem><para>The specified file descriptor is 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 <constant>NULL</constant>, where
that is not accepted).</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENOMEM</constant></term>
<listitem><para>Memory allocation failed.</para></listitem>
</varlistentry>
</variablelist>
</refsect2>
</refsect1>
<refsect1>
<title>Notes</title>
<xi:include href="libsystemd-pkgconfig.xml" xpointer="pkgconfig-text"/>
<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>History</title>
<para><function>sd_peer_get_cgroup()</function>,
<function>sd_peer_get_machine_name()</function>,
<function>sd_peer_get_owner_uid()</function>,
<function>sd_peer_get_session()</function>,
<function>sd_peer_get_slice()</function>,
<function>sd_peer_get_unit()</function>,
<function>sd_peer_get_user_slice()</function>,
<function>sd_peer_get_user_unit()</function>,
<function>sd_pid_get_cgroup()</function>,
<function>sd_pid_get_machine_name()</function>,
<function>sd_pid_get_owner_uid()</function>,
<function>sd_pid_get_session()</function>,
<function>sd_pid_get_slice()</function>,
<function>sd_pid_get_unit()</function>,
<function>sd_pid_get_user_slice()</function>, and
<function>sd_pid_get_user_unit()</function> were added in version 236.</para>
<para><function>sd_pidfd_get_owner_uid()</function>,
<function>sd_pidfd_get_session()</function>,
<function>sd_pidfd_get_user_unit()</function>,
<function>sd_pidfd_get_unit()</function>,
<function>sd_pidfd_get_machine_name()</function>,
<function>sd_pidfd_get_slice()</function>,
<function>sd_pidfd_get_user_slice()</function>, and
<function>sd_pidfd_get_cgroup()</function> were added in version 253.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para><simplelist type="inline">
<member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_session_is_active</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
</simplelist></para>
</refsect1>
</refentry>
|
