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- "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 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,
+ <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>
+
+ <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 <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
+ is 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>,
+ <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 <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 <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>,
+ <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 a shared library, which can be
+ compiled and linked to with the
+ <constant>libelogind</constant> <citerefentry project='die-net'><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>
~ianmdlvl / elogind.git / blobdiff