<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
- "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
-<!-- SPDX-License-Identifier: LGPL-2.1+ -->
+ "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
+<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="sd_bus_negotiate_fds" xmlns:xi="http://www.w3.org/2001/XInclude">
<refname>sd_bus_negotiate_fds</refname>
<refname>sd_bus_negotiate_timestamp</refname>
<refname>sd_bus_negotiate_creds</refname>
+ <refname>sd_bus_get_creds_mask</refname>
<refpurpose>Control feature negotiation on bus connections</refpurpose>
</refnamediv>
<paramdef>int <parameter>b</parameter></paramdef>
<paramdef>uint64_t <parameter>mask</parameter></paramdef>
</funcprototype>
+
+ <funcprototype>
+ <funcdef>int <function>sd_bus_get_creds_mask</function></funcdef>
+ <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+ <paramdef>uint64_t *<parameter>mask</parameter></paramdef>
+ </funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
- <para><function>sd_bus_negotiate_fds()</function> controls whether
- file descriptor passing shall be negotiated for the specified bus
- connection. It takes a bus object and a boolean, which, when true,
- enables file descriptor passing, and, when false, disables
- it. Note that not all transports and servers support file
- descriptor passing. In particular, networked transports generally
- do not support file descriptor passing. To find out whether file
- descriptor passing is available after negotiation, use
+ <para><function>sd_bus_negotiate_fds()</function> controls whether file descriptor passing shall be
+ negotiated for the specified bus connection. It takes a bus object and a boolean, which, when true,
+ enables file descriptor passing, and, when false, disables it. Note that not all transports and servers
+ support file descriptor passing. In particular, networked transports generally do not support file
+ descriptor passing. To find out whether file descriptor passing is available after negotiation, use
<citerefentry><refentrytitle>sd_bus_can_send</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- and pass <constant>SD_BUS_TYPE_UNIX_FD</constant>. Note that file
- descriptor passing is always enabled for both sending and
- receiving or for neither, but never only in one direction. By
- default, file descriptor passing is negotiated for all
- connections.</para>
-
- <para><function>sd_bus_negotiate_timestamp()</function> controls whether implicit sender
- timestamps shall be attached automatically to all incoming messages. Takes a bus object and a
- boolean, which, when true, enables timestamping, and, when false, disables it. Use
+ and pass <constant>SD_BUS_TYPE_UNIX_FD</constant>. Note that file descriptor passing is always enabled
+ for both sending and receiving or for neither, but never only in one direction. By default, file
+ descriptor passing is negotiated for all connections.</para>
+
+ <para><function>sd_bus_negotiate_timestamp()</function> controls whether implicit sender timestamps shall
+ be attached automatically to all incoming messages. Takes a bus object and a boolean, which, when true,
+ enables timestamping, and, when false, disables it. Use
<citerefentry><refentrytitle>sd_bus_message_get_monotonic_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_get_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_get_seqnum</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- to query the timestamps of incoming messages. If negotiation is disabled or not supported, these
- calls will fail with <constant>-ENODATA</constant>. Note that currently no transports support
- timestamping of messages. By default, message timestamping is not negotiated for
- connections.</para>
+ to query the timestamps of incoming messages. If negotiation is disabled or not supported, these calls
+ will fail with <constant>-ENODATA</constant>. Note that currently no transports support timestamping of
+ messages. By default, message timestamping is not negotiated for connections.</para>
<para><function>sd_bus_negotiate_creds()</function> controls whether and which implicit sender
- credentials shall be attached automatically to all incoming messages. Takes a bus object and a
- boolean indicating whether to enable or disable the credential parts encoded in the bit mask
- value argument. Note that not all transports support attaching sender credentials to messages,
- or do not support all types of sender credential parameters, or might suppress them under
- certain circumstances for individual messages. Specifically, dbus1 only supports
- <constant>SD_BUS_CREDS_UNIQUE_NAME</constant>. The sender credentials are suitable for
- authorization decisions. By default, only <constant>SD_BUS_CREDS_WELL_KNOWN_NAMES</constant> and
- <constant>SD_BUS_CREDS_UNIQUE_NAME</constant> are enabled. In fact, these two credential fields
- are always sent along and cannot be turned off.</para>
-
- <para>The <function>sd_bus_negotiate_fds()</function> function may
- be called only before the connection has been started with
+ credentials shall be attached automatically to all incoming messages. Takes a bus object and a boolean
+ indicating whether to enable or disable the credential parts encoded in the bit mask value argument. Note
+ that not all transports support attaching sender credentials to messages, or do not support all types of
+ sender credential parameters, or might suppress them under certain circumstances for individual messages.
+ Specifically, dbus1 only supports <constant>SD_BUS_CREDS_UNIQUE_NAME</constant>. The sender credentials
+ are suitable for authorization decisions. By default, only
+ <constant>SD_BUS_CREDS_WELL_KNOWN_NAMES</constant> and <constant>SD_BUS_CREDS_UNIQUE_NAME</constant> are
+ enabled. In fact, these two credential fields are always sent along and cannot be turned off.</para>
+
+ <para><function>sd_bus_get_creds_mask()</function> returns the set of sender credentials that was
+ negotiated to be attached to all incoming messages in <parameter>mask</parameter>. This value is an
+ upper boundary only. Hence, always make sure to explicitly check which credentials are attached to a
+ specific message before using it.</para>
+
+ <para>The <function>sd_bus_negotiate_fds()</function> function may be called only before the connection
+ has been started with
<citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Both
- <function>sd_bus_negotiate_timestamp()</function> and
- <function>sd_bus_negotiate_creds()</function> may also be called
- after a connection has been set up. Note that, when operating on a
- connection that is shared between multiple components of the same
- program (for example via
- <citerefentry><refentrytitle>sd_bus_default</refentrytitle><manvolnum>3</manvolnum></citerefentry>),
- it is highly recommended to only enable additional per message
- metadata fields, but never disable them again, in order not to
- disable functionality needed by other components.</para>
+ <function>sd_bus_negotiate_timestamp()</function> and <function>sd_bus_negotiate_creds()</function> may
+ also be called after a connection has been set up. Note that, when operating on a connection that is
+ shared between multiple components of the same program (for example via
+ <citerefentry><refentrytitle>sd_bus_default</refentrytitle><manvolnum>3</manvolnum></citerefentry>), it
+ is highly recommended to only enable additional per message metadata fields, but never disable them
+ again, in order not to disable functionality needed by other components.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
- <para>On success, these functions return 0 or a
- positive integer. On failure, they return a negative errno-style
- error code.</para>
- </refsect1>
+ <para>On success, these functions return a non-negative integer. On failure, they return a negative
+ errno-style error code.</para>
- <refsect1>
- <title>Errors</title>
+ <refsect2>
+ <title>Errors</title>
+
+ <para>Returned errors may indicate the following problems:</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><constant>-EPERM</constant></term>
+
+ <listitem><para>The bus connection has already been started.</para></listitem>
+ </varlistentry>
- <para>Returned errors may indicate the following problems:</para>
+ <varlistentry>
+ <term><constant>-EINVAL</constant></term>
- <variablelist>
- <varlistentry>
- <term><constant>-EPERM</constant></term>
+ <listitem><para>An argument is invalid.</para>
- <listitem><para>The bus connection has already been started.</para></listitem>
- </varlistentry>
- </variablelist>
+ <xi:include href="version-info.xml" xpointer="v246"/></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-ENOPKG</constant></term>
+
+ <listitem><para>The bus cannot be resolved.</para>
+
+ <xi:include href="version-info.xml" xpointer="v246"/></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-ECHILD</constant></term>
+
+ <listitem><para>The bus was created in a different process, library or module instance.</para>
+
+ <xi:include href="version-info.xml" xpointer="v246"/></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect2>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
+ <refsect1>
+ <title>History</title>
+ <para><function>sd_bus_negotiate_fds()</function>,
+ <function>sd_bus_negotiate_timestamp()</function>, and
+ <function>sd_bus_negotiate_creds()</function> were added in version 212.</para>
+ <para><function>sd_bus_get_creds_mask()</function> was added in version 246.</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_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_bus_message_can_send</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_bus_message_get_monotonic_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_bus_message_get_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_bus_message_get_seqnum</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- </para>
+ <para><simplelist type="inline">
+ <member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>sd_bus_can_send</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>sd_bus_message_get_monotonic_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>sd_bus_message_get_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>sd_bus_message_get_seqnum</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
+ </simplelist></para>
</refsect1>
</refentry>
projects / thirdparty / systemd.git / blobdiff