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<refentry id="sd_bus_creds_get_pid">

<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_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 &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_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 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 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. 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 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 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 indicates 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, 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 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>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_get_unit()</function>,

<function>sd_bus_get_slice()</function>,

<function>sd_bus_get_user_unit()</function>,

<function>sd_bus_get_user_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 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>

<refsect1>

<title>Notes</title>

<para><function>sd_bus_creds_get_pid()</function> and the 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>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>