mirror of
https://github.com/systemd/systemd.git
synced 2024-11-02 19:21:53 +03:00
247 lines
12 KiB
XML
247 lines
12 KiB
XML
<?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_login_monitor_new" conditional='HAVE_PAM'>
|
|
|
|
<refentryinfo>
|
|
<title>sd_login_monitor_new</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_login_monitor_new</refentrytitle>
|
|
<manvolnum>3</manvolnum>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>sd_login_monitor_new</refname>
|
|
<refname>sd_login_monitor_unref</refname>
|
|
<refname>sd_login_monitor_flush</refname>
|
|
<refname>sd_login_monitor_get_fd</refname>
|
|
<refname>sd_login_monitor_get_events</refname>
|
|
<refname>sd_login_monitor_get_timeout</refname>
|
|
<refname>sd_login_monitor</refname>
|
|
<refpurpose>Monitor login sessions, seats, users and virtual machines/containers</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<funcsynopsis>
|
|
<funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo>
|
|
|
|
<funcprototype>
|
|
<funcdef>int <function>sd_login_monitor_new</function></funcdef>
|
|
<paramdef>const char* <parameter>category</parameter></paramdef>
|
|
<paramdef>sd_login_monitor** <parameter>ret</parameter></paramdef>
|
|
</funcprototype>
|
|
|
|
<funcprototype>
|
|
<funcdef>sd_login_monitor* <function>sd_login_monitor_unref</function></funcdef>
|
|
<paramdef>sd_login_monitor* <parameter>m</parameter></paramdef>
|
|
</funcprototype>
|
|
|
|
<funcprototype>
|
|
<funcdef>int <function>sd_login_monitor_flush</function></funcdef>
|
|
<paramdef>sd_login_monitor* <parameter>m</parameter></paramdef>
|
|
</funcprototype>
|
|
|
|
<funcprototype>
|
|
<funcdef>int <function>sd_login_monitor_get_fd</function></funcdef>
|
|
<paramdef>sd_login_monitor* <parameter>m</parameter></paramdef>
|
|
</funcprototype>
|
|
|
|
<funcprototype>
|
|
<funcdef>int <function>sd_login_monitor_get_events</function></funcdef>
|
|
<paramdef>sd_login_monitor* <parameter>m</parameter></paramdef>
|
|
</funcprototype>
|
|
|
|
<funcprototype>
|
|
<funcdef>int <function>sd_login_monitor_get_timeout</function></funcdef>
|
|
<paramdef>sd_login_monitor* <parameter>m</parameter></paramdef>
|
|
<paramdef>uint64_t* <parameter>timeout_usec</parameter></paramdef>
|
|
</funcprototype>
|
|
|
|
</funcsynopsis>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para><function>sd_login_monitor_new()</function> may
|
|
be used to monitor login sessions, users, seats, and
|
|
virtual machines/containers. Via a monitor object a
|
|
file descriptor can be integrated into an application
|
|
defined event loop which is woken up each time a user
|
|
logs in, logs out or a seat is added or removed, or a
|
|
session, user, seat or virtual machine/container
|
|
changes state otherwise. The first parameter takes a
|
|
string which can be <literal>seat</literal> (to get
|
|
only notifications about seats being added, removed or
|
|
changed), <literal>session</literal> (to get only
|
|
notifications about sessions being created or removed
|
|
or changed), <literal>uid</literal> (to get only
|
|
notifications when a user changes state in respect to
|
|
logins) or <literal>machine</literal> (to get only
|
|
notifications when a virtual machine or container is
|
|
started or stopped). If notifications shall be
|
|
generated in all these conditions, NULL may be
|
|
passed. Note that in the future additional categories
|
|
may be defined. The second parameter returns a monitor
|
|
object and needs to be freed with the
|
|
<function>sd_login_monitor_unref()</function> call
|
|
after use.</para>
|
|
|
|
<para><function>sd_login_monitor_unref()</function>
|
|
may be used to destroy a monitor object. Note that
|
|
this will invalidate any file descriptor returned by
|
|
<function>sd_login_monitor_get_fd()</function>.</para>
|
|
|
|
<para><function>sd_login_monitor_flush()</function>
|
|
may be used to reset the wakeup state of the monitor
|
|
object. Whenever an event causes the monitor to wake
|
|
up the event loop via the file descriptor this
|
|
function needs to be called to reset the wake-up
|
|
state. If this call is not invoked the file descriptor
|
|
will immediately wake up the event loop again.</para>
|
|
|
|
<para><function>sd_login_monitor_get_fd()</function>
|
|
may be used to retrieve the file descriptor of the
|
|
monitor object that may be integrated in an
|
|
application defined event loop, based around
|
|
<citerefentry><refentrytitle>poll</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
|
or a similar interface. The application should include
|
|
the returned file descriptor as wake-up source for the
|
|
events mask returned by
|
|
<function>sd_login_monitor_get_events()</function>. It
|
|
should pass a timeout value as returned by
|
|
<function>sd_login_monitor_get_timeout()</function>. Whenever
|
|
a wake-up is triggered the file descriptor needs to be
|
|
reset via
|
|
<function>sd_login_monitor_flush()</function>. An
|
|
application needs to reread the login state with a
|
|
function like
|
|
<citerefentry><refentrytitle>sd_get_seats</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
|
or similar to determine what changed.</para>
|
|
|
|
<para><function>sd_login_monitor_get_events()</function>
|
|
will return the <function>poll()</function> mask to
|
|
wait for. This function will return a combination of
|
|
<literal>POLLIN</literal>, <literal>POLLOUT</literal>
|
|
and similar to fill into the
|
|
<literal>.events</literal> field of <literal>struct
|
|
pollfd</literal>.</para>
|
|
|
|
<para><function>sd_login_monitor_get_timeout()</function>
|
|
will return a timeout value for usage in
|
|
<function>poll()</function>. This returns a value in
|
|
microseconds since the epoch of CLOCK_MONOTONIC for
|
|
timing out <function>poll()</function> in
|
|
<literal>timeout_usec</literal>. See
|
|
<citerefentry><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
|
for details about
|
|
<literal>CLOCK_MONOTONIC</literal>. If there's no
|
|
timeout to wait for this will fill in
|
|
<literal>(uint64_t) -1</literal> instead. Note that
|
|
<function>poll()</function> takes a relative timeout
|
|
in milliseconds rather than an absolute timeout in
|
|
microseconds. To convert the absolute 'us' timeout into
|
|
relative 'ms', use code like the following:</para>
|
|
|
|
<programlisting>uint64_t t;
|
|
int msec;
|
|
sd_login_monitor_get_timeout(m, &t);
|
|
if (t == (uint64_t) -1)
|
|
msec = -1;
|
|
else {
|
|
struct timespec ts;
|
|
uint64_t n;
|
|
clock_getttime(CLOCK_MONOTONIC, &ts);
|
|
n = (uint64_t) ts.tv_sec * 1000000 + ts.tv_nsec / 1000;
|
|
msec = t > n ? (int) ((t - n + 999) / 1000) : 0;
|
|
}</programlisting>
|
|
|
|
<para>The code above does not do any error checking
|
|
for brevity's sake. The calculated <literal>msec</literal>
|
|
integer can be passed directly as
|
|
<function>poll()</function>'s timeout
|
|
parameter.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Return Value</title>
|
|
|
|
<para>On success
|
|
<function>sd_login_monitor_new()</function>,
|
|
<function>sd_login_monitor_flush()</function> and
|
|
<function>sd_login_monitor_get_timeout()</function>
|
|
return 0 or a positive integer. On success
|
|
<function>sd_login_monitor_get_fd()</function> returns
|
|
a Unix file descriptor. On success
|
|
<function>sd_login_monitor_get_events()</function>
|
|
returns a combination of <literal>POLLIN</literal>,
|
|
<literal>POLLOUT</literal> and suchlike. On failure,
|
|
these calls return a negative errno-style error
|
|
code.</para>
|
|
|
|
<para><function>sd_login_monitor_unref()</function>
|
|
always returns NULL.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Notes</title>
|
|
|
|
<para>The <function>sd_login_monitor_new()</function>,
|
|
<function>sd_login_monitor_unref()</function>,
|
|
<function>sd_login_monitor_flush()</function>,
|
|
<function>sd_login_monitor_get_fd()</function>,
|
|
<function>sd_login_monitor_get_events()</function> and
|
|
<function>sd_login_monitor_get_timeout()</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>
|
|
</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_get_seats</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>poll</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|