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>
+ <refname>sd_login_monitor_get_events</refname>
+ <refname>sd_login_monitor_get_timeout</refname>
<refname>sd_login_monitor</refname>
<refpurpose>Monitor login sessions, seats and users</refpurpose>
</refnamediv>
<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
+ be used to monitor login sessions, 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
+ 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
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
+ 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
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
+ <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> 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 <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>
<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
+ <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>
<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>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