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<refentry id="sd_bus_creds_get_pid" conditional="ENABLE_KDBUS">
<refentryinfo>
<title>sd_bus_creds_get_pid</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>A monkey with a typewriter</contrib>
<firstname>Zbigniew</firstname>
<surname>Jędrzejewski-Szmek</surname>
<email>zbyszek@in.waw.pl</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_creds_get_pid</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_creds_get_pid</refname>
<refname>sd_bus_creds_get_ppid</refname>
<refname>sd_bus_creds_get_tid</refname>
<refname>sd_bus_creds_get_uid</refname>
<refname>sd_bus_creds_get_euid</refname>
<refname>sd_bus_creds_get_suid</refname>
<refname>sd_bus_creds_get_fsuid</refname>
<refname>sd_bus_creds_get_gid</refname>
<refname>sd_bus_creds_get_egid</refname>
<refname>sd_bus_creds_get_sgid</refname>
<refname>sd_bus_creds_get_fsgid</refname>
<refname>sd_bus_creds_get_supplementary_gids</refname>
<refname>sd_bus_creds_get_comm</refname>
<refname>sd_bus_creds_get_tid_comm</refname>
<refname>sd_bus_creds_get_exe</refname>
<refname>sd_bus_creds_get_cmdline</refname>
<refname>sd_bus_creds_get_cgroup</refname>
<refname>sd_bus_creds_get_unit</refname>
<refname>sd_bus_creds_get_user_unit</refname>
<refname>sd_bus_creds_get_slice</refname>
<refname>sd_bus_creds_get_session</refname>
<refname>sd_bus_creds_get_owner_uid</refname>
<refname>sd_bus_creds_has_effective_cap</refname>
<refname>sd_bus_creds_has_permitted_cap</refname>
<refname>sd_bus_creds_has_inheritable_cap</refname>
<refname>sd_bus_creds_has_bounding_cap</refname>
<refname>sd_bus_creds_get_selinux_context</refname>
<refname>sd_bus_creds_get_audit_session_id</refname>
<refname>sd_bus_creds_get_audit_login_uid</refname>
<refname>sd_bus_creds_get_tty</refname>
<refname>sd_bus_creds_get_unique_name</refname>
<refname>sd_bus_creds_get_well_known_names</refname>
<refname>sd_bus_creds_get_description</refname>
<refpurpose>Retrieve fields from a credentials object</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_pid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>pid_t *<parameter>pid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_ppid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>pid_t *<parameter>ppid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_tid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>pid_t *<parameter>tid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_uid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>uid_t *<parameter>uid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_euid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>uid_t *<parameter>uid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_suid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>uid_t *<parameter>uid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_fsuid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>uid_t *<parameter>uid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_gid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>gid_t *<parameter>gid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_egid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>gid_t *<parameter>gid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_sgid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>gid_t *<parameter>gid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_fsgid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>gid_t *<parameter>gid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_supplementary_gids</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const gid_t **<parameter>gids</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_comm</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const char **<parameter>comm</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_tid_comm</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const char **<parameter>comm</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_exe</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const char **<parameter>exe</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_cmdline</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>char ***<parameter>cmdline</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_cgroup</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const char **<parameter>cgroup</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_unit</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const char **<parameter>unit</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_user_unit</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const char **<parameter>unit</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_slice</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const char **<parameter>slice</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_session</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const char **<parameter>slice</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_owner_uid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>uid_t *<parameter>uid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_has_effective_cap</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>int <parameter>capability</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_has_permitted_cap</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>int <parameter>capability</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_has_inheritable_cap</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>int <parameter>capability</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_has_bounding_cap</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>int <parameter>capability</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_selinux_context</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const char **<parameter>context</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_audit_session_id</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>uint32_t *<parameter>sessionid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_audit_login_uid</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>uid_t *<parameter>loginuid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_tty</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const char **<parameter>tty</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_unique_name</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const char **<parameter>name</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_well_known_names</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>char ***<parameter>name</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_creds_get_description</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>const char **<parameter>name</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>These functions return information from an
<parameter>sd_bus_creds</parameter> credential object. Credential
objects may be created with
<citerefentry><refentrytitle>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
in which case they describe the credentials of the process
identified by the specified PID, with
<citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
in which case they describe the credentials of a bus peer
identified by the specified bus name, or with
<citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
in which case they describe the credentials of the creator of a
bus.</para>
<para><function>sd_bus_creds_get_pid()</function> will retrieve
the PID (process identifier). Similar,
<function>sd_bus_creds_get_ppid()</function> will retrieve the
parent PID. Note that PID 1 has no parent process, in which case
-ENXIO is returned.</para>
<para><function>sd_bus_creds_get_tid()</function> will retrieve the
TID (thread identifier).</para>
<para><function>sd_bus_creds_get_uid()</function> will retrieve
the numeric UID (user identifier). Similar,
<function>sd_bus_creds_get_euid()</function> returns the effective
UID, <function>sd_bus_creds_get_suid()</function> the saved UID
and <function>sd_bus_creds_get_fsuid()</function> the file system
UID.</para>
<para><function>sd_bus_creds_get_gid()</function> will retrieve the
numeric GID (group identifier). Similar,
<function>sd_bus_creds_get_egid()</function> returns the effective
GID, <function>sd_bus_creds_get_sgid()</function> the saved GID
and <function>sd_bus_creds_get_fsgid()</function> the file system
GID.</para>
<para><function>sd_bus_creds_get_supplementary_gids()</function>
will retrieve the supplementary GIDs list.</para>
<para><function>sd_bus_creds_get_comm()</function> will retrieve the
comm field (truncated name of the executable, as stored in
<filename>/proc/<replaceable>pid</replaceable>/comm</filename>).
</para>
<para><function>sd_bus_creds_get_tid_comm()</function> will retrieve
the comm field of the thread (as stored in
<filename>/proc/<replaceable>pid</replaceable>/task/<replaceable>tid</replaceable>/comm</filename>).
</para>
<para><function>sd_bus_creds_get_exe()</function> will retrieve
the path to the program executable (as stored in the
<filename>/proc/<replaceable>pid</replaceable>/exe</filename>
link, but with <literal> (deleted)</literal> suffix removed). Note
that kernel threads do not have an executable path, in which case
-ENXIO is returned.</para>
<para><function>sd_bus_creds_get_cmdline()</function> will
retrieve an array of command line arguments (as stored in
<filename>/proc/<replaceable>pid</replaceable>/cmdline</filename>). Note
that kernel threads do not have a command line, in which case
-ENXIO is returned.</para>
<para><function>sd_bus_creds_get_cgroup()</function> will retrieve
the cgroup path. See <ulink
url="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>.
</para>
<para><function>sd_bus_creds_get_unit()</function> will retrieve
the systemd unit name (in the system instance of systemd) that the
process is part of. See
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
processes that are not part of a unit returns -ENXIO.
</para>
<para><function>sd_bus_creds_get_user_unit()</function> will
retrieve the systemd unit name (in the user instance of systemd)
that the process is part of. See
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
processes that are not part of a user unit returns -ENXIO.
</para>
<para><function>sd_bus_creds_get_slice()</function> will retrieve
the systemd slice (a unit in the system instance of systemd) that
the process is part of. See
<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
<para><function>sd_bus_creds_get_session()</function> will
retrieve the logind session that the process is part of. See
<citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. For
processes that are not part of a session returns -ENXIO.
</para>
<para><function>sd_bus_creds_get_owner_uid()</function> will
retrieve the numeric UID (user identifier) of the user who owns
the session that the process is part of. See
<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>
For processes that are not part of a session returns -ENXIO.
</para>
<para><function>sd_bus_creds_has_effective_cap()</function> will
check whether the capability specified by
<parameter>capability</parameter> 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
<citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
and <varname>Capabilities=</varname> and
<varname>CapabilityBoundingSet=</varname> settings in
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
<para><function>sd_bus_creds_has_permitted_cap()</function> is
similar to <function>sd_bus_creds_has_effective_cap()</function>,
but will check the permitted capabilities mask.</para>
<para><function>sd_bus_creds_has_inheritable_cap()</function> is
similar to <function>sd_bus_creds_has_effective_cap()</function>,
but will check the inheritable capabilities mask.</para>
<para><function>sd_bus_creds_has_bounding_cap()</function> is
similar to <function>sd_bus_creds_has_effective_cap()</function>,
but will check the bounding capabilities mask.</para>
<para><function>sd_bus_creds_get_selinux_context()</function> will
retrieve the SELinux security context (label) of the process.</para>
<para><function>sd_bus_creds_get_audit_session_id()</function>
will retrieve the audit session identifier of the process. Returns
-ENXIO for processes that are not part of an audit session.</para>
<para><function>sd_bus_creds_get_audit_login_uid()</function> 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.</para>
<para><function>sd_bus_creds_get_tty()</function> will retrieve
the controlling TTY. Returns -ENXIO for processes that have no
controlling TTY.</para>
<para><function>sd_bus_creds_get_unique_name()</function> will
retrieve the D-Bus unique name. See <ulink
url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
D-Bus specification</ulink>.</para>
<para><function>sd_bus_creds_get_well_known_names()</function> will
retrieve the set of D-Bus well-known names. See <ulink
url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
D-Bus specification</ulink>.</para>
<para><function>sd_bus_creds_get_description()</function> 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
<citerefentry><refentrytitle>sd_bus_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call.</para>
<para>All functions that take a <parameter>const
char**</parameter> parameter will store the answer there as an
address of a NUL-terminated string. It will be valid as long as
<parameter>c</parameter> remains valid, and should not be freed or
modified by the caller.</para>
<para>All functions that take a <parameter>char***</parameter>
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
<parameter>c</parameter> remains valid, and should not be freed or
modified by the caller.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>On success, these calls return 0 or a positive integer. On
failure, these calls return a negative errno-style error code.
</para>
</refsect1>
<refsect1>
<title>Errors</title>
<para>Returned errors may indicate the following problems:</para>
<variablelist>
<varlistentry>
<term><constant>-ENODATA</constant></term>
<listitem><para>Given field is not available in the
credentials object <parameter>c</parameter>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENXIO</constant></term>
<listitem><para>Given field is not specified for the described
process or peer. This will be returned by
<function>sd_bus_get_unit()</function>,
<function>sd_bus_get_user_unit()</function>,
<function>sd_bus_get_slice()</function>,
<function>sd_bus_get_session()</function>, and
<function>sd_bus_get_owner_uid()</function> 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
<function>sd_bus_creds_get_exe()</function> and
<function>sd_bus_creds_get_cmdline()</function> for kernel
threads (since these aren't started from an executable binary
or have a command line),
<function>sd_bus_creds_get_audit_session_id()</function> and
<function>sd_bus_creds_get_audit_login_uid()</function> when
the process is not part of an audit session, and
<function>sd_bus_creds_get_tty()</function> if the process has
no controlling TTY.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>-EINVAL</constant></term>
<listitem><para>Specified pointer parameter is <constant>NULL</constant>.
</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENOMEM</constant></term>
<listitem><para>Memory allocation failed.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Notes</title>
<para><function>sd_bus_open_user()</function> and other functions
described here are available as a shared library, which can be
compiled and linked to with the
<constant>libsystemd</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-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
<citerefentry><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>credentials</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>