| <?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"> |
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| Copyright 2010 Lennart Poettering |
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| |
| <refentry id="sd_login_monitor_new"> |
| |
| <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> |
| <refpurpose>Monitor login sessions, seats and users</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> |
| |
| </funcsynopsis> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para><function>sd_login_monitor_new()</function> may |
| be used to monitor login session, users and seats. 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, or seat changes |
| state otherwise. The first parameter takes a string |
| which can be either <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) or <literal>uid</literal> (to get only |
| notifications when a user changes state in respect to |
| logins). If notifications shall be generated in all |
| these conditions, NULL may be passed. Note that in |
| 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 |
| POLLIN events. 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> |
| </refsect1> |
| |
| <refsect1> |
| <title>Return Value</title> |
| |
| <para>On success |
| <function>sd_login_monitor_new()</function> and |
| <function>sd_login_monitor_flush()</function> return 0 |
| or a positive integer. On success |
| <function>sd_login_monitor_get_fd()</function> returns |
| a Unix file descriptor. 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> and |
| <function>sd_login_monitor_get_fd()</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>7</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_get_seats</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
| </para> |
| </refsect1> |
| |
| </refentry> |