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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>sd_bus_creds_get_pid</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><style>
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  <span style="float:right">systemd 221</span><hr><div class="refentry"><a name="sd_bus_creds_get_pid"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd_bus_creds_get_pid, sd_bus_creds_get_ppid, sd_bus_creds_get_tid, sd_bus_creds_get_uid, sd_bus_creds_get_euid, sd_bus_creds_get_suid, sd_bus_creds_get_fsuid, sd_bus_creds_get_gid, sd_bus_creds_get_egid, sd_bus_creds_get_sgid, sd_bus_creds_get_fsgid, sd_bus_creds_get_supplementary_gids, sd_bus_creds_get_comm, sd_bus_creds_get_tid_comm, sd_bus_creds_get_exe, sd_bus_creds_get_cmdline, sd_bus_creds_get_cgroup, sd_bus_creds_get_unit, sd_bus_creds_get_user_unit, sd_bus_creds_get_slice, sd_bus_creds_get_session, sd_bus_creds_get_owner_uid, sd_bus_creds_has_effective_cap, sd_bus_creds_has_permitted_cap, sd_bus_creds_has_inheritable_cap, sd_bus_creds_has_bounding_cap, sd_bus_creds_get_selinux_context, sd_bus_creds_get_audit_session_id, sd_bus_creds_get_audit_login_uid, sd_bus_creds_get_tty, sd_bus_creds_get_unique_name, sd_bus_creds_get_well_known_names, sd_bus_creds_get_description — Retrieve fields from a credentials object</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include &lt;systemd/sd-bus.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_bus_creds_get_pid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>pid_t *<var class="pdparam">pid</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_bus_creds_get_ppid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>pid_t *<var class="pdparam">ppid</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_bus_creds_get_tid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>pid_t *<var class="pdparam">tid</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_bus_creds_get_uid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>uid_t *<var class="pdparam">uid</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_bus_creds_get_euid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>uid_t *<var class="pdparam">uid</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_bus_creds_get_suid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>uid_t *<var class="pdparam">uid</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_bus_creds_get_fsuid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>uid_t *<var class="pdparam">uid</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_bus_creds_get_gid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>gid_t *<var class="pdparam">gid</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_bus_creds_get_egid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>gid_t *<var class="pdparam">gid</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_bus_creds_get_sgid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>gid_t *<var class="pdparam">gid</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_bus_creds_get_fsgid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>gid_t *<var class="pdparam">gid</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_bus_creds_get_supplementary_gids</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const gid_t **<var class="pdparam">gids</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_bus_creds_get_comm</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const char **<var class="pdparam">comm</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_bus_creds_get_tid_comm</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const char **<var class="pdparam">comm</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_bus_creds_get_exe</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const char **<var class="pdparam">exe</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_bus_creds_get_cmdline</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>char ***<var class="pdparam">cmdline</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_bus_creds_get_cgroup</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const char **<var class="pdparam">cgroup</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_bus_creds_get_unit</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const char **<var class="pdparam">unit</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_bus_creds_get_user_unit</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const char **<var class="pdparam">unit</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_bus_creds_get_slice</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const char **<var class="pdparam">slice</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_bus_creds_get_session</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const char **<var class="pdparam">slice</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_bus_creds_get_owner_uid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>uid_t *<var class="pdparam">uid</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_bus_creds_has_effective_cap</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">capability</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_bus_creds_has_permitted_cap</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">capability</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_bus_creds_has_inheritable_cap</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">capability</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_bus_creds_has_bounding_cap</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">capability</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_bus_creds_get_selinux_context</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const char **<var class="pdparam">context</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_bus_creds_get_audit_session_id</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>uint32_t *<var class="pdparam">sessionid</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_bus_creds_get_audit_login_uid</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>uid_t *<var class="pdparam">loginuid</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_bus_creds_get_tty</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const char **<var class="pdparam">tty</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_bus_creds_get_unique_name</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const char **<var class="pdparam">name</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_bus_creds_get_well_known_names</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>char ***<var class="pdparam">name</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_bus_creds_get_description</b>(</code></td><td>sd_bus_creds *<var class="pdparam">c</var>, </td></tr><tr><td> </td><td>const char **<var class="pdparam">name</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idm47928340647264"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p>These functions return information from an
    <em class="parameter"><code>sd_bus_creds</code></em> credential object. Credential
    objects may be created with
    <a href="sd_bus_creds_new_from_pid.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_creds_new_from_pid</span>(3)</span></a>,
    in which case they describe the credentials of the process
    identified by the specified PID, with
    <a href="sd_bus_get_name_creds.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_get_name_creds</span>(3)</span></a>,
    in which case they describe the credentials of a bus peer
    identified by the specified bus name, with
    <a href="sd_bus_get_owner_creds.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_get_owner_creds</span>(3)</span></a>,
    in which case they describe the credentials of the creator of a
    bus, or with
    <a href="sd_bus_message_get_creds.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_message_get_creds</span>(3)</span></a>,
    in which case they describe the credentials of the sender of the message.</p><p><code class="function">sd_bus_creds_get_pid()</code> will retrieve
    the PID (process identifier). Similar,
    <code class="function">sd_bus_creds_get_ppid()</code> will retrieve the
    parent PID. Note that PID 1 has no parent process, in which case
    -ENXIO is returned.</p><p><code class="function">sd_bus_creds_get_tid()</code> will retrieve the
    TID (thread identifier).</p><p><code class="function">sd_bus_creds_get_uid()</code> will retrieve
    the numeric UID (user identifier). Similar,
    <code class="function">sd_bus_creds_get_euid()</code> returns the effective
    UID, <code class="function">sd_bus_creds_get_suid()</code> the saved UID
    and <code class="function">sd_bus_creds_get_fsuid()</code> the file system
    UID.</p><p><code class="function">sd_bus_creds_get_gid()</code> will retrieve the
    numeric GID (group identifier). Similar,
    <code class="function">sd_bus_creds_get_egid()</code> returns the effective
    GID, <code class="function">sd_bus_creds_get_sgid()</code> the saved GID
    and <code class="function">sd_bus_creds_get_fsgid()</code> the file system
    GID.</p><p><code class="function">sd_bus_creds_get_supplementary_gids()</code>
    will retrieve the supplementary GIDs list.</p><p><code class="function">sd_bus_creds_get_comm()</code> will retrieve the
    comm field (truncated name of the executable, as stored in
    <code class="filename">/proc/<em class="replaceable"><code>pid</code></em>/comm</code>).
    </p><p><code class="function">sd_bus_creds_get_tid_comm()</code> will retrieve
    the comm field of the thread (as stored in
    <code class="filename">/proc/<em class="replaceable"><code>pid</code></em>/task/<em class="replaceable"><code>tid</code></em>/comm</code>).
    </p><p><code class="function">sd_bus_creds_get_exe()</code> will retrieve
    the path to the program executable (as stored in the
    <code class="filename">/proc/<em class="replaceable"><code>pid</code></em>/exe</code>
    link, but with "<code class="literal"> (deleted)</code>" suffix removed). Note
    that kernel threads do not have an executable path, in which case
    -ENXIO is returned.</p><p><code class="function">sd_bus_creds_get_cmdline()</code> will
    retrieve an array of command line arguments (as stored in
    <code class="filename">/proc/<em class="replaceable"><code>pid</code></em>/cmdline</code>). Note
    that kernel threads do not have a command line, in which case
    -ENXIO is returned.</p><p><code class="function">sd_bus_creds_get_cgroup()</code> will retrieve
    the cgroup path. See <a class="ulink" href="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt" target="_top">cgroups.txt</a>.
    </p><p><code class="function">sd_bus_creds_get_unit()</code> will retrieve
    the systemd unit name (in the system instance of systemd) that the
    process is part of. See
    <a href="systemd.unit.html"><span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span></a>. For
    processes that are not part of a unit returns -ENXIO.
    </p><p><code class="function">sd_bus_creds_get_user_unit()</code> will
    retrieve the systemd unit name (in the user instance of systemd)
    that the process is part of. See
    <a href="systemd.unit.html"><span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span></a>. For
    processes that are not part of a user unit returns -ENXIO.
    </p><p><code class="function">sd_bus_creds_get_slice()</code> will retrieve
    the systemd slice (a unit in the system instance of systemd) that
    the process is part of. See
    <a href="systemd.slice.html"><span class="citerefentry"><span class="refentrytitle">systemd.slice</span>(5)</span></a>.
    </p><p><code class="function">sd_bus_creds_get_session()</code> will
    retrieve the logind session that the process is part of. See
    <a href="systemd-logind.service.html"><span class="citerefentry"><span class="refentrytitle">systemd-logind.service</span>(8)</span></a>. For
    processes that are not part of a session returns -ENXIO.
    </p><p><code class="function">sd_bus_creds_get_owner_uid()</code> will
    retrieve the numeric UID (user identifier) of the user who owns
    the session that the process is part of. See
    <a href="systemd.slice.html"><span class="citerefentry"><span class="refentrytitle">systemd.slice</span>(5)</span></a>
    For processes that are not part of a session returns -ENXIO.
    </p><p><code class="function">sd_bus_creds_has_effective_cap()</code> will
    check whether the capability specified by
    <em class="parameter"><code>capability</code></em> was set in the effective
    capabilities mask. A positive return value means that is was
    set, zero means that it was not set, and a negative return
    value signifies an error. See
    <a href="http://man7.org/linux/man-pages/man7/capabilities.7.html"><span class="citerefentry"><span class="refentrytitle">capabilities</span>(7)</span></a>
    and <code class="varname">Capabilities=</code> and
    <code class="varname">CapabilityBoundingSet=</code> settings in
    <a href="systemd.exec.html"><span class="citerefentry"><span class="refentrytitle">systemd.exec</span>(5)</span></a>.
    </p><p><code class="function">sd_bus_creds_has_permitted_cap()</code> is
    similar to <code class="function">sd_bus_creds_has_effective_cap()</code>,
    but will check the permitted capabilities mask.</p><p><code class="function">sd_bus_creds_has_inheritable_cap()</code> is
    similar to <code class="function">sd_bus_creds_has_effective_cap()</code>,
    but will check the inheritable capabilities mask.</p><p><code class="function">sd_bus_creds_has_bounding_cap()</code> is
    similar to <code class="function">sd_bus_creds_has_effective_cap()</code>,
    but will check the bounding capabilities mask.</p><p><code class="function">sd_bus_creds_get_selinux_context()</code> will
    retrieve the SELinux security context (label) of the process.</p><p><code class="function">sd_bus_creds_get_audit_session_id()</code>
    will retrieve the audit session identifier of the process. Returns
    -ENXIO for processes that are not part of an audit session.</p><p><code class="function">sd_bus_creds_get_audit_login_uid()</code> will
    retrieve the audit user login identifier (the identifier of the
    user who is "responsible" for the session). Returns -ENXIO for
    processes that are not part of an audit session.</p><p><code class="function">sd_bus_creds_get_tty()</code> will retrieve
    the controlling TTY. Returns -ENXIO for processes that have no
    controlling TTY.</p><p><code class="function">sd_bus_creds_get_unique_name()</code> will
    retrieve the D-Bus unique name. See <a class="ulink" href="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus" target="_top">The
    D-Bus specification</a>.</p><p><code class="function">sd_bus_creds_get_well_known_names()</code> will
    retrieve the set of D-Bus well-known names. See <a class="ulink" href="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus" target="_top">The
    D-Bus specification</a>.</p><p><code class="function">sd_bus_creds_get_description()</code> will
    retrieve a descriptive name of the bus connection of the
    peer. This name is useful to discern multiple bus connections by
    the same peer, and may be altered by the peer with the
    <a href="sd_bus_set_description.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_set_description</span>(3)</span></a>
    call.</p><p>All functions that take a <em class="parameter"><code>const
    char**</code></em> parameter will store the answer there as an
    address of a NUL-terminated string. It will be valid as long as
    <em class="parameter"><code>c</code></em> remains valid, and should not be freed or
    modified by the caller.</p><p>All functions that take a <em class="parameter"><code>char***</code></em>
    parameter will store the answer there as an address of a an array
    of strings. Each individual string is NUL-terminated, and the
    array is NULL-terminated as a whole. It will be valid as long as
    <em class="parameter"><code>c</code></em> remains valid, and should not be freed or
    modified by the caller.</p></div><div class="refsect1"><a name="idm47928340591680"></a><h2 id="Return Value">Return Value<a class="headerlink" title="Permalink to this headline" href="#Return%20Value">¶</a></h2><p>On success, these calls return 0 or a positive integer. On
    failure, these calls return a negative errno-style error code.
    </p></div><div class="refsect1"><a name="idm47928340590384"></a><h2 id="Errors">Errors<a class="headerlink" title="Permalink to this headline" href="#Errors">¶</a></h2><p>Returned errors may indicate the following problems:</p><div class="variablelist"><dl class="variablelist"><dt id="-ENODATA"><span class="term"><code class="constant">-ENODATA</code></span><a class="headerlink" title="Permalink to this term" href="#-ENODATA">¶</a></dt><dd><p>Given field is not available in the
        credentials object <em class="parameter"><code>c</code></em>.</p></dd><dt id="-ENXIO"><span class="term"><code class="constant">-ENXIO</code></span><a class="headerlink" title="Permalink to this term" href="#-ENXIO">¶</a></dt><dd><p>Given field is not specified for the described
        process or peer. This will be returned by
        <code class="function">sd_bus_get_unit()</code>,
        <code class="function">sd_bus_get_user_unit()</code>,
        <code class="function">sd_bus_get_slice()</code>,
        <code class="function">sd_bus_get_session()</code>, and
        <code class="function">sd_bus_get_owner_uid()</code> if the process is
        not part of a systemd system unit, systemd user unit, systemd
        slice, or logind session. It will also be returned by
        <code class="function">sd_bus_creds_get_exe()</code> and
        <code class="function">sd_bus_creds_get_cmdline()</code> for kernel
        threads (since these aren't started from an executable binary
        or have a command line),
        <code class="function">sd_bus_creds_get_audit_session_id()</code> and
        <code class="function">sd_bus_creds_get_audit_login_uid()</code> when
        the process is not part of an audit session, and
        <code class="function">sd_bus_creds_get_tty()</code> if the process has
        no controlling TTY.
        </p></dd><dt id="-EINVAL"><span class="term"><code class="constant">-EINVAL</code></span><a class="headerlink" title="Permalink to this term" href="#-EINVAL">¶</a></dt><dd><p>Specified pointer parameter is <code class="constant">NULL</code>.
        </p></dd><dt id="-ENOMEM"><span class="term"><code class="constant">-ENOMEM</code></span><a class="headerlink" title="Permalink to this term" href="#-ENOMEM">¶</a></dt><dd><p>Memory allocation failed.</p></dd></dl></div></div><div class="refsect1"><a name="idm47928340575024"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes">¶</a></h2><p><code class="function">sd_bus_open_user()</code> and other functions
    described here are available as a shared library, which can be
    compiled and linked to with the
    <code class="constant">libsystemd</code> <a href="http://linux.die.net/man/1/pkg-config"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
    file.</p></div><div class="refsect1"><a name="idm47928340571840"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
      <a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
      <a href="sd-bus.html"><span class="citerefentry"><span class="refentrytitle">sd-bus</span>(3)</span></a>,
      <a href="http://man7.org/linux/man-pages/man2/fork.2.html"><span class="citerefentry"><span class="refentrytitle">fork</span>(2)</span></a>,
      <a href="http://man7.org/linux/man-pages/man2/execve.2.html"><span class="citerefentry"><span class="refentrytitle">execve</span>(2)</span></a>,
      <a href="http://man7.org/linux/man-pages/man7/credentials.7.html"><span class="citerefentry"><span class="refentrytitle">credentials</span>(7)</span></a>,
      <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>,
      <a href="http://man7.org/linux/man-pages/man5/proc.5.html"><span class="citerefentry"><span class="refentrytitle">proc</span>(5)</span></a>,
      <a href="systemd.journal-fields.html"><span class="citerefentry"><span class="refentrytitle">systemd.journal-fields</span>(7)</span></a>
    </p></div></div></body></html>