dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim<?xml version='1.0'?> <!--*-nxml-*-->

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim<refentry id="sd_bus_creds_get_pid">

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refentryinfo>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <title>sd_bus_creds_get_pid</title>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <productname>systemd</productname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere <authorgroup>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <author>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <contrib>A monkey with a typewriter</contrib>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <firstname>Zbigniew</firstname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <surname>Jędrzejewski-Szmek</surname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <email>zbyszek@in.waw.pl</email>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim </author>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim </authorgroup>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim </refentryinfo>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refmeta>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refentrytitle>sd_bus_creds_get_pid</refentrytitle>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <manvolnum>3</manvolnum>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim </refmeta>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refnamediv>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_pid</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_pid_starttime</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_tid</refname>

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere <refname>sd_bus_creds_get_uid</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_gid</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_comm</refname>

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere <refname>sd_bus_creds_get_tid_comm</refname>

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere <refname>sd_bus_creds_get_exe</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_cmdline</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_cgroup</refname>

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere <refname>sd_bus_creds_get_unit</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_user_unit</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_slice</refname>

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere <refname>sd_bus_creds_get_session</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_owner_uid</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_has_effective_cap</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_has_permitted_cap</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_has_inheritable_cap</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_has_bounding_cap</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_selinux_context</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_audit_session_id</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refname>sd_bus_creds_get_audit_login_uid</refname>

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere <refname>sd_bus_creds_get_unique_name</refname>

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere <refname>sd_bus_creds_get_well_known_names</refname>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <refpurpose>Retrieve fields from a credentials object</refpurpose>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim </refnamediv>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere <refsynopsisdiv>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcsynopsis>

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcdef>int <function>sd_bus_creds_get_pid</function></funcdef>

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere <paramdef>sd_bus_creds* <parameter>c</parameter></paramdef>

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere <paramdef>pid_t *<parameter>pid</parameter></paramdef>

834fc281be8e0f7f2614961f12d8bbf603382a17jfclere </funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcdef>int <function>sd_bus_creds_get_pid_starttime</function></funcdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>sd_bus_creds* <parameter>c</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>uint64_t *<parameter>usec</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim </funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcdef>int <function>sd_bus_creds_get_tid</function></funcdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>sd_bus_creds* <parameter>c</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>pid_t *<parameter>tid</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim </funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcdef>int <function>sd_bus_creds_get_pid</function></funcdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>sd_bus_creds* <parameter>c</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>uid_t *<parameter>uid</parameter></paramdef>

23a31b10f869a72c9197b5f153f4f3e1a4c68f28jim </funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcdef>int <function>sd_bus_creds_get_gid</function></funcdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>sd_bus_creds* <parameter>c</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>gid_t *<parameter>gid</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim </funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

2c4ed36c350564e8bfb68e9d9ba58fe77b9bf3c0jim <funcprototype>

6bed231822ad2aaba16de74c4c01023e5982a5e2jfclere <funcdef>int <function>sd_bus_creds_get_comm</function></funcdef>

2c4ed36c350564e8bfb68e9d9ba58fe77b9bf3c0jim <paramdef>sd_bus_creds* <parameter>c</parameter></paramdef>

2c4ed36c350564e8bfb68e9d9ba58fe77b9bf3c0jim <paramdef>const char **<parameter>comm</parameter></paramdef>

2c4ed36c350564e8bfb68e9d9ba58fe77b9bf3c0jim </funcprototype>

2c4ed36c350564e8bfb68e9d9ba58fe77b9bf3c0jim

2c4ed36c350564e8bfb68e9d9ba58fe77b9bf3c0jim <funcprototype>

2c4ed36c350564e8bfb68e9d9ba58fe77b9bf3c0jim <funcdef>int <function>sd_bus_creds_get_tid_comm</function></funcdef>

2c4ed36c350564e8bfb68e9d9ba58fe77b9bf3c0jim <paramdef>sd_bus_creds* <parameter>c</parameter></paramdef>

2c4ed36c350564e8bfb68e9d9ba58fe77b9bf3c0jim <paramdef>const char **<parameter>comm</parameter></paramdef>

b1e3273c2e70ad5ac64feef979b2ed1d98c09963jim </funcprototype>

b1e3273c2e70ad5ac64feef979b2ed1d98c09963jim

6bed231822ad2aaba16de74c4c01023e5982a5e2jfclere <funcprototype>

b1e3273c2e70ad5ac64feef979b2ed1d98c09963jim <funcdef>int <function>sd_bus_creds_get_exe</function></funcdef>

b1e3273c2e70ad5ac64feef979b2ed1d98c09963jim <paramdef>sd_bus_creds* <parameter>c</parameter></paramdef>

b1e3273c2e70ad5ac64feef979b2ed1d98c09963jim <paramdef>const char **<parameter>exe</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim </funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcdef>int <function>sd_bus_creds_get_cmdline</function></funcdef>

9a0e1ad272fdbe3fee989e93bdae8253418429edjfclere <paramdef>sd_bus_creds* <parameter>c</parameter></paramdef>

b1e3273c2e70ad5ac64feef979b2ed1d98c09963jim <paramdef>char ***<parameter>cmdline</parameter></paramdef>

9a0e1ad272fdbe3fee989e93bdae8253418429edjfclere </funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcdef>int <function>sd_bus_creds_get_cgroup</function></funcdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>sd_bus_creds* <parameter>c</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>const char **<parameter>cgroup</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim </funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcprototype>

36ef8f77bffe75d1aa327882be1b5bdbe2ff567asf <funcdef>int <function>sd_bus_creds_get_unit</function></funcdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>sd_bus_creds* <parameter>c</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>const char **<parameter>unit</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim </funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcprototype>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <funcdef>int <function>sd_bus_creds_get_user_unit</function></funcdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <paramdef>sd_bus_creds* <parameter>c</parameter></paramdef>

dfcadcd3e6bbdee594540b8f8e4e50586a2e3219jim <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>Those 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

UID (user identifier).</para>

<para><function>sd_bus_creds_get_gid</function> will retrieve the

GID (group identifier).</para>

<para><function>sd_bus_creds_get_comm</function> will retrieve the

comm field (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 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 all of the capabilities specified by

<parameter>capability</parameter> were set in the effective

capabilities mask. A positive return value means that they were

set, zero means that they were not set, and a negative return

value signifies an error. See

<citerefentry><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 context 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><varname>-ENODATA</varname></term>

<listitem><para>Given field is not available in

<parameter>c</parameter>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>-ENOENT</varname></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><varname>-EINVAL</varname></term>

<listitem><para>Specified pointer parameter is <constant>NULL</constant>.

</para></listitem>

</varlistentry>

<varlistentry>

<term><varname>-ENOMEM</varname></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-bus</constant> <citerefentry><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>credentials</refentrytitle><manvolnum>7</manvolnum></citerefentry>,

<citerefentry><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry>,

<citerefentry><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>,

<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.journald-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>

</para>

</refsect1>

</refentry>