man/sd_uid_get_sessions.html

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  22   <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 208</span><hr><div class="refentry"><a name="sd_uid_get_state"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd_uid_get_state, sd_uid_is_on_seat, sd_uid_get_sessions, sd_uid_get_seats — Determine login state of a specific Unix user ID</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include &lt;systemd/sd-login.h&gt;</pre><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_uid_get_state</b>(</code></td><td>uid_t <var class="pdparam">uid</var>, </td></tr><tr><td> </td><td>char** <var class="pdparam">state</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_uid_is_on_seat</b>(</code></td><td>uid_t <var class="pdparam">uid</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">require_active</var>, </td></tr><tr><td> </td><td>const char* <var class="pdparam">seat</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_uid_get_sessions</b>(</code></td><td>uid_t <var class="pdparam">uid</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">require_active</var>, </td></tr><tr><td> </td><td>char*** <var class="pdparam">sessions</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_uid_get_seats</b>(</code></td><td>uid_t <var class="pdparam">uid</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">require_active</var>, </td></tr><tr><td> </td><td>char*** <var class="pdparam">seats</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idm274686615328"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p><code class="function">sd_uid_get_state()</code> may be
  23                 used to determine the login state of a specific Unix
  24                 user identifier. The following states are currently
  25                 known: "<code class="literal">offline</code>" (user not logged in
  26                 at all), "<code class="literal">lingering</code>" (user not logged
  27                 in, but some user services running),
  28                 "<code class="literal">online</code>" (user logged in, but not
  29                 active, i.e. has no session in the foreground),
  30                 "<code class="literal">active</code>" (user logged in, and has at
  31                 least one active session, i.e. one session in the
  32                 foreground), "<code class="literal">closing</code>" (user not
  33                 logged in, and not lingering, but some processes are
  34                 still around). In the future additional states might
  35                 be defined, client code should be written to be robust
  36                 in regards to additional state strings being
  37                 returned. The returned string needs to be freed with
  38                 the libc
  39                 <a href="free.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
  40                 call after use.</p><p><code class="function">sd_uid_is_on_seat()</code> may be
  41                 used to determine whether a specific user is logged in
  42                 or active on a specific seat. Accepts a Unix user
  43                 identifier and a seat identifier string as
  44                 parameters. The <em class="parameter"><code>require_active</code></em>
  45                 parameter is a boolean value. If non-zero (true), this
  46                 function will test if the user is active (i.e. has a
  47                 session that is in the foreground and accepting user
  48                 input) on the specified seat, otherwise (false) only
  49                 if the user is logged in (and possibly inactive) on
  50                 the specified seat.</p><p><code class="function">sd_uid_get_sessions()</code> may
  51                 be used to determine the current sessions of the
  52                 specified user. Accepts a Unix user identifier as
  53                 parameter. The <em class="parameter"><code>require_active</code></em>
  54                 parameter controls whether the returned list shall
  55                 consist of only those sessions where the user is
  56                 currently active (&gt; 0), where the user is currently
  57                 online but possibly inactive (= 0), or
  58                 logged in at all but possibly closing the session (&lt; 0). The call returns a
  59                 <code class="constant">NULL</code> terminated string array of session identifiers in
  60                 <em class="parameter"><code>sessions</code></em> which needs to be
  61                 freed by the caller with the libc
  62                 <a href="free.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
  63                 call after use, including all the strings
  64                 referenced. If the string array parameter is passed as
  65                 <code class="constant">NULL</code>, the array will not be filled in, but the return
  66                 code still indicates the number of current
  67                 sessions. Note that instead of an empty array <code class="constant">NULL</code> may
  68                 be returned and should be considered equivalent to an
  69                 empty array.</p><p>Similar, <code class="function">sd_uid_get_seats()</code>
  70                 may be used to determine the list of seats on which
  71                 the user currently has sessions. Similar semantics
  72                 apply, however note that the user may have
  73                 multiple sessions on the same seat as well as sessions
  74                 with no attached seat and hence the number of entries
  75                 in the returned array may differ from the one returned
  76                 by <code class="function">sd_uid_get_sessions()</code>.</p></div><div class="refsect1"><a name="idm274686574336"></a><h2 id="Return Value">Return Value<a class="headerlink" title="Permalink to this headline" href="#Return%20Value">¶</a></h2><p>On success
  77                 <code class="function">sd_uid_get_state()</code> returns 0 or a
  78                 positive integer. If the test succeeds,
  79                 <code class="function">sd_uid_is_on_seat()</code> returns a
  80                 positive integer, if it fails
  81                 0. <code class="function">sd_uid_get_sessions()</code> and
  82                 <code class="function">sd_uid_get_seats()</code> return the
  83                 number of entries in the returned arrays. On failure,
  84                 these calls return a negative errno-style error
  85                 code.</p></div><div class="refsect1"><a name="idm274686570032"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes">¶</a></h2><p>The <code class="function">sd_uid_get_state()</code>,
  86                 <code class="function">sd_uid_is_on_seat()</code>,
  87                 <code class="function">sd_uid_get_sessions()</code>, and
  88                 <code class="function">sd_uid_get_seats()</code> interfaces are
  89                 available as shared library, which can be compiled and
  90                 linked to with the <code class="constant">libsystemd-login</code> <a href="pkg-config.html"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
  91                 file.</p></div><div class="refsect1"><a name="idm274686676912"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
  92                         <a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
  93                         <a href="sd-login.html"><span class="citerefentry"><span class="refentrytitle">sd-login</span>(3)</span></a>,
  94                         <a href="sd_pid_get_owner_uid.html"><span class="citerefentry"><span class="refentrytitle">sd_pid_get_owner_uid</span>(3)</span></a>
  95                 </p></div></div></body></html>