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<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>flags</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
<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,
+ 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>
- 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. By default, message timestamping is
- not negotiated for all 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 not all transports
+ support timestamping of messages. Specifically, timestamping is
+ only available on the kdbus transport, but not on dbus1. The
+ timestamping is applied by the kernel and cannot be manipulated by
+ userspace. By default, message timestamping is not negotiated for
+ connections.</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, a
+ 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. 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>
+ messages. Specifically, implicit sender credentials on messages
+ are only fully supported on kdbus transports, and dbus1 only
+ supports <constant>SD_BUS_CREDS_UNIQUE_NAME</constant>. The sender
+ credentials are attached by the kernel and cannot be manipulated
+ by userspace, and are thus 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> also may be called
- after a connection has been set up. Note that when operating on a
+ <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>)
+ <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>
<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>
<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>
<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>,
<citerefentry><refentrytitle>systemd.busname</refentrytitle><manvolnum>5</manvolnum></citerefentry>
</para>
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