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<refentry id="sd_bus_creds_get_pid" xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_bus_creds_get_pid</title>
<productname>systemd</productname>
</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_slice</refname>
<refname>sd_bus_creds_get_user_unit</refname>
<refname>sd_bus_creds_get_user_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 <systemd/sd-bus.h></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_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_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_user_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 credential information from an
<parameter>sd_bus_creds</parameter> 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, 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, or with
<citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
in which case they describe the credentials of the sender of the
message.</para>
<para>Not all credential fields are part of every
<literal>sd_bus_creds</literal> object. Use
<citerefentry><refentrytitle>sd_bus_creds_get_mask</refentrytitle><manvolnum>3</manvolnum></citerefentry>
to determine the mask of fields available.</para>
<para><function>sd_bus_creds_get_pid()</function> will retrieve
the PID (process identifier). Similarly,
<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). Similarly,
<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). Similarly,
<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 the <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 control group path. See <ulink
url="https://www.kernel.org/doc/Documentation/cgroup-v1/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 a 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 a 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 a part of. See
<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Similarly,
<function>sd_bus_creds_get_user_slice()</function> retrieves the
systemd slice of the process, in the user instance of systemd.
</para>
<para><function>sd_bus_creds_get_session()</function> will
retrieve the identifier of the login session that the process is
a part of. Please note the login session may be limited to a stub
process or two. User processes may instead be started from their
systemd user manager, e.g. GUI applications started using DBus
activation, as well as service processes which are shared between
multiple logins of the same user. 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 user unit or login session that the process is a part of. See
<citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
For processes that are not part of a user unit or 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 it
was set, zero means that it was not set, and a negative return value indicates an error. See <citerefentry
project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> and the
<varname>AmbientCapabilities=</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, without the prefixing "/dev/". 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 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>The given field is not available in the
credentials object <parameter>c</parameter>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENXIO</constant></term>
<listitem><para>The given field is not specified for the described
process or peer. This will be returned by
<function>sd_bus_creds_get_unit()</function>,
<function>sd_bus_creds_get_slice()</function>,
<function>sd_bus_creds_get_user_unit()</function>,
<function>sd_bus_creds_get_user_slice()</function>, and
<function>sd_bus_creds_get_session()</function> if the process is
not part of a systemd system unit, systemd user unit, systemd
slice, or logind session. It will be returned by
<function>sd_bus_creds_get_owner_uid()</function> if the process is
not part of a systemd user unit 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 are not started from an executable binary,
nor have a command line), and by
<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>
<xi:include href="libsystemd-pkgconfig.xml" />
<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>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
<citerefentry project='man-pages'><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>