mirror of
https://github.com/systemd/systemd.git
synced 2024-11-01 00:51:24 +03:00
bc9e9af137
The -ENOMEDIUM return value was introduced in v232-1001-g2977724b09,
('core: make hybrid cgroup unified mode keep compat /sys/fs/cgroup/systemd hierarchy'),
and would be returned by cg_pid_get_path_shifted(), but the documented and
expected return value is -ENODATA. Let's just catch ENXIO/ENOMEDIUM and translate
it to ENODATA in all cases.
Complements 171f8f591f, fixes #6012.
360 lines
15 KiB
XML
360 lines
15 KiB
XML
<?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
|
||
<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>-EBADF</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>libsystemd</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>
|