sd_bus_creds_get_pid.xml revision b7ea3f3ed6204dca31f8f2a84b667c1783259c5b
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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_pid_starttime</refname>
<refname>sd_bus_creds_get_tid</refname>
<refname>sd_bus_creds_get_uid</refname>
<refname>sd_bus_creds_get_gid</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_unique_name</refname>
<refname>sd_bus_creds_get_well_known_names</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_pid_starttime</function></funcdef>
<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
<paramdef>uint64_t *<parameter>usec</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_pid</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_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_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>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>These functions return information from an
<parameter>sd_bus_creds</parameter> object. It may be created with
<citerefentry><refentrytitle>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
in which case it will describe the specified process, or it may be
created by
<citerefentry><refentrytitle>sd_bus_get_peer_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
in which case it will describe the process at the other endpoint
of a connection.
</para>
<para><function>sd_bus_creds_get_pid()</function> will retrieve the
PID (process identifier).</para>
<para><function>sd_bus_creds_get_pid_starttime()</function> will
retrieve the time since the start of the epoch in microseconds
since the process was started.</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).</para>
<para><function>sd_bus_creds_get_gid()</function> will retrieve the
numeric GID (group identifier).</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 (as stored in the
<filename>/proc/<replaceable>pid</replaceable>/exe</filename>
link, but with <literal> (deleted)</literal> suffix removed).
</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>).
</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>.
</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>.
</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>.
</para>
<para><function>sd_bus_creds_get_owner_uid()</function> will retrieve
the numeric UID (user identifier) of the user who owns the slice
that the process is part of. See
<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>
<!-- and
<citerefentry><refentrytitle>systemd-user-sessions.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> -->.
</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.</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).</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>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 invidividual 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
<parameter>c</parameter>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENOENT</constant></term>
<listitem><para>Given field is not specified for the sender.
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 sender is not
part of a systemd system unit, systemd user unit, systemd
slice, logind session, or a systemd user session.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENXIO</constant></term>
<listitem><para>An error occurred in parsing cgroup paths.
<filename>libsystemd</filename> might be out of sync with
the running systemd version.</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.journald-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>