-<?xml version='1.0'?> <!--*-nxml-*-->
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
-This file is part of systemd.
+ This file is part of systemd.
-Copyright 2014 Lennart Poettering
+ Copyright 2014 Lennart Poettering
-systemd is free software; you can redistribute it and/or modify it
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-(at your option) any later version.
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
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+ Lesser General Public License for more details.
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-->
-<refentry id="sd_bus_negotiate_fds" conditional="ENABLE_KDBUS">
+<refentry id="sd_bus_negotiate_fds">
<refentryinfo>
<title>sd_bus_negotiate_fds</title>
<refnamediv>
<refname>sd_bus_negotiate_fds</refname>
- <refname>sd_bus_negotiate_timestamps</refname>
+ <refname>sd_bus_negotiate_timestamp</refname>
<refname>sd_bus_negotiate_creds</refname>
<refpurpose>Control feature negotiation on bus connections</refpurpose>
<funcdef>int <function>sd_bus_negotiate_creds</function></funcdef>
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
<paramdef>int <parameter>b</parameter></paramdef>
+ <paramdef>uint64_t <parameter>mask</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<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. To find out whether file descriptor passing is available
- after negotiation, use
+ 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
setting as negotiated by the program ultimately activated. By
default, file descriptor passing is enabled for both.</para>
- <para><function>sd_bus_negotiate_timestamps()</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. If
- this is disabled,
+ <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_seqno</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- fail with <constant>-ENODATA</constant> on incoming messages. Note
- that not all transports support timestamping of messages. On local
- transports, the timestamping is applied by the kernel and cannot be
- manipulated by userspace.</para>
-
- <para><function>sd_bus_negotiate_creds()</function> controls
- whether implicit sender credentials shall be attached
- automatically to all incoming messages. Takes a bus object and a
- bit mask value, which controls which credential parameters are
- attached. If this is not used,
- <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- fails with <constant>-ENODATA</constant> on incoming
- messages. Note that not all transports support attaching sender
- credentials to messages, or do not support all types of sender
- credential parameters. On local transports, the sender credentials
- are attached by the kernel and cannot be manipulated by
- userspace. By default, no sender credentials are attached.</para>
-
- <para>These functions may be called only before the connection has
- been started with
- <citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
+ <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>
+
+ <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
+ <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>
</refsect1>
<refsect1>
<title>Return Value</title>
- <para>On success, these functions returns 0 or a
+ <para>On success, these functions return 0 or a
positive integer. On failure, they return a negative errno-style
error code.</para>
</refsect1>
<variablelist>
<varlistentry>
- <term><varname>-EPERM</varname></term>
+ <term><constant>-EPERM</constant></term>
<listitem><para>The bus connection has already been started.</para></listitem>
</varlistentry>
<refsect1>
<title>Notes</title>
- <para><function>sd_bus_negotiate_fs()</function> and the other
+ <para><function>sd_bus_negotiate_fds()</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>
+ <constant>libelogind</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
file.</para>
</refsect1>
<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_creds</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>,
+ <citerefentry><refentrytitle>systemd.busname</refentrytitle><manvolnum>5</manvolnum></citerefentry>
</para>
</refsect1>