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Diffstat (limited to 'src/libsystemd/sd_bus_negotiate_fds.xml')
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diff --git a/src/libsystemd/sd_bus_negotiate_fds.xml b/src/libsystemd/sd_bus_negotiate_fds.xml new file mode 100644 index 0000000000..1501e1427d --- /dev/null +++ b/src/libsystemd/sd_bus_negotiate_fds.xml @@ -0,0 +1,186 @@ +<?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. + + Copyright 2014 Lennart Poettering + + 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 + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +--> + +<refentry id="sd_bus_negotiate_fds"> + + <refentryinfo> + <title>sd_bus_negotiate_fds</title> + <productname>systemd</productname> + + <authorgroup> + <author> + <contrib>Developer</contrib> + <firstname>Lennart</firstname> + <surname>Poettering</surname> + <email>lennart@poettering.net</email> + </author> + </authorgroup> + </refentryinfo> + + <refmeta> + <refentrytitle>sd_bus_negotiate_fds</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_bus_negotiate_fds</refname> + <refname>sd_bus_negotiate_timestamp</refname> + <refname>sd_bus_negotiate_creds</refname> + + <refpurpose>Control feature negotiation on bus connections</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> + + <funcprototype> + <funcdef>int <function>sd_bus_negotiate_fds</function></funcdef> + <paramdef>sd_bus *<parameter>bus</parameter></paramdef> + <paramdef>int <parameter>b</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_bus_negotiate_timestamp</function></funcdef> + <paramdef>sd_bus *<parameter>bus</parameter></paramdef> + <paramdef>int <parameter>b</parameter></paramdef> + </funcprototype> + + <funcprototype> + <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> + + <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 + <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>Note that when bus activation is used, it is highly + recommended to set the <option>AcceptFileDescriptors=</option> + setting in the <filename>.busname</filename> unit file to the same + setting as negotiated by the program ultimately activated. By + default, file descriptor passing is enabled for both.</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> + + <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 return 0 or a + positive integer. On failure, they 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>-EPERM</constant></term> + + <listitem><para>The bus connection has already been started.</para></listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Notes</title> + + <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> + 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_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> + </refsect1> + +</refentry> |