systemd/man/sd_session_is_active.xml
Lennart Poettering 5430f7f2bc relicense to LGPLv2.1 (with exceptions)
We finally got the OK from all contributors with non-trivial commits to
relicense systemd from GPL2+ to LGPL2.1+.

Some udev bits continue to be GPL2+ for now, but we are looking into
relicensing them too, to allow free copy/paste of all code within
systemd.

The bits that used to be MIT continue to be MIT.

The big benefit of the relicensing is that closed source code may now
link against libsystemd-login.so and friends.
2012-04-12 00:24:39 +02:00

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<?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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<refentry id="sd_session_is_active">
<refentryinfo>
<title>sd_session_is_active</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_session_is_active</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_session_is_active</refname>
<refname>sd_session_get_uid</refname>
<refname>sd_session_get_seat</refname>
<refname>sd_session_get_service</refname>
<refname>sd_session_get_type</refname>
<refname>sd_session_get_class</refname>
<refname>sd_session_get_display</refname>
<refpurpose>Determine state of a specific session</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-login.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_session_is_active</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_uid</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>uid_t* <parameter>uid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_seat</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>seat</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_service</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>service</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_type</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>type</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_class</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>class</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_display</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>display</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_session_is_active()</function> may
be used to determine whether the session identified by
the specified session identifier is currently active
(i.e. currently in the foreground and available for
user input) or not.</para>
<para><function>sd_session_get_uid()</function> may be
used to determine the user identifier of the Unix user the session
identified by the specified session identifier belongs
to.</para>
<para><function>sd_session_get_seat()</function> may
be used to determine the seat identifier of the seat
the session identified by the specified session
identifier belongs to. Note that not all sessions are
attached to a seat, this call will fail for them. The
returned string needs to be freed with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_session_get_service()</function>
may be used to determine the name of the service (as
passed during PAM session setup) that registered the
session identified by the specified session
identifier. The returned string needs to be freed with
the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_session_get_type()</function> may
be used to determine the type of the session
identified by the specified session identifier. The
returned string is one of <literal>x11</literal>,
<literal>tty</literal> or
<literal>unspecified</literal> and needs to be freed
with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_session_get_class()</function> may
be used to determine the class of the session
identified by the specified session identifier. The
returned string is one of <literal>user</literal>,
<literal>greeter</literal> or
<literal>lock-screen</literal> and needs to be freed
with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_session_get_display()</function>
may be used to determine the X11 display of the
session identified by the specified session
identifier. The returned string is one of needs to be
freed with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para>If the <literal>session</literal> parameter of
any of these functions is passed as NULL the operation
is executed for the session the calling process is a
member of, if there is any.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>If the test succeeds
<function>sd_session_is_active()</function> returns a
positive integer, if it fails 0. On success
<function>sd_session_get_uid()</function>,
<function>sd_session_get_service()</function> and
<function>sd_session_get_seat()</function> return 0 or
a positive integer. On failure, these calls return a
negative errno-style error code.</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>The <function>sd_session_is_active()</function>,
<function>sd_session_get_uid()</function>,
<function>sd_session_get_service()</function> and
<function>sd_session_get_seat()</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_pid_get_session</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>