Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ 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
- General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU General Public License
+ 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">
+<refentry id="sd_login_monitor_new" conditional='HAVE_PAM'>
<refentryinfo>
<title>sd_login_monitor_new</title>
<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>
+ <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>
<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>
<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
+ 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) or <literal>uid</literal> (to get only
+ or changed), <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
+ 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, <constant>NULL</constant> 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>
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
+ 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
+ <constant>POLLIN</constant>, <constant>POLLOUT</constant>
+ and similar to fill into the
+ <literal>.events</literal> field of <varname>struct
+ pollfd</varname>.</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 <constant>CLOCK_MONOTONIC</constant>
+ for timing out <function>poll()</function> in
+ <varname>timeout_usec</varname>. See
+ <citerefentry><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ for details about
+ <constant>CLOCK_MONOTONIC</constant>. If there's no
+ timeout to wait for this will fill in
+ <constant>(uint64_t) -1</constant> 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 <varname>msec</varname>
+ 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> and
- <function>sd_login_monitor_flush()</function> return 0
- or a positive integer. 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 failure, these calls return
- a negative errno-style error code.</para>
+ a Unix file descriptor. On success
+ <function>sd_login_monitor_get_events()</function>
+ returns a combination of <constant>POLLIN</constant>,
+ <constant>POLLOUT</constant> 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>
+ always returns <constant>NULL</constant>.</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>
+ <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
+ <constant>libsystemd-login</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
file.</para>
</refsect1>
<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>
+ <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>
~ianmdlvl / elogind.git / blobdiff