sd-bus: sd_bus_call/sd_bus_call_async_docs + cleanups.

This commit is contained in:
Daan De Meyer 2020-03-17 21:52:30 +01:00 committed by Zbigniew Jędrzejewski-Szmek
parent b48772f6cb
commit 953ee402cb
6 changed files with 200 additions and 9 deletions

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@ -137,6 +137,7 @@ manpages = [
'sd_bus_add_fallback_vtable'],
''],
['sd_bus_attach_event', '3', ['sd_bus_detach_event', 'sd_bus_get_event'], ''],
['sd_bus_call', '3', ['sd_bus_call_async'], ''],
['sd_bus_call_method', '3', ['sd_bus_call_method_async'], ''],
['sd_bus_close', '3', ['sd_bus_flush'], ''],
['sd_bus_creds_get_pid',

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@ -43,6 +43,8 @@
<literallayout><citerefentry><refentrytitle>sd_bus_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_add_object_vtable</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_call_async</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_call_method</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_call_method_async</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_creds_get_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

186
man/sd_bus_call.xml Normal file
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@ -0,0 +1,186 @@
<?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+ -->
<refentry id="sd_bus_call"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_bus_call</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_call</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_call</refname>
<refname>sd_bus_call_async</refname>
<refpurpose>Invoke a D-Bus method call</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_bus_call</function></funcdef>
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
<paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
<paramdef>uint64_t <parameter>usec</parameter></paramdef>
<paramdef>sd_bus_error *<parameter>ret_error</parameter></paramdef>
<paramdef>sd_bus_message **<parameter>reply</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_call_async</function></funcdef>
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
<paramdef>sd_bus_slot **<parameter>slot</parameter></paramdef>
<paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
<paramdef>sd_bus_message_handler_t <parameter>callback</parameter></paramdef>
<paramdef>void *<parameter>userdata</parameter></paramdef>
<paramdef>uint64_t <parameter>usec</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_bus_call()</function> takes a complete bus message object and calls the
corresponding D-Bus method. The response is stored in <parameter>reply</parameter>.
<parameter>usec</parameter> indicates the timeout in microseconds. If
<parameter>ret_error</parameter> is not <constant>NULL</constant> and
<function>sd_bus_call()</function> returns an error, <parameter>ret_error</parameter> is
initialized to an instance of <structname>sd_bus_error</structname> describing the error.</para>
<para><function>sd_bus_call_async()</function> is like <function>sd_bus_call()</function> but
works asynchronously. The <parameter>callback</parameter> shall reference a function to call
when the event source is triggered. The <parameter>userdata</parameter> pointer will be passed
to the callback function, and may be chosen freely by the caller. If <parameter>slot</parameter>
is not <constant>NULL</constant> and <function>sd_bus_call_async()</function> succeeds,
<parameter>slot</parameter> is set to a slot object which can be used to cancel the method call
at a later time using
<citerefentry><refentrytitle>sd_bus_slot_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
If <parameter>slot</parameter> is <constant>NULL</constant>, the lifetime of the method call is
bound to the lifetime of the bus object itself, and it cannot be cancelled independently. See
<citerefentry><refentrytitle>sd_bus_slot_set_floating</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for details. The <parameter>callback</parameter> function is called when the response arrives
and receives the response, <parameter>userdata</parameter> and a
<structname>sd_bus_error</structname> object as its arguments. The
<structname>sd_bus_error</structname> object is unused here and should be ignored. If
<parameter>callback</parameter> returns a non-negative integer when called, a debug message is
logged along with details about the response.</para>
<para>To determine whether the method call succeeded, use
<citerefentry><refentrytitle>sd_bus_message_is_method_error</refentrytitle><manvolnum>3</manvolnum></citerefentry>
on the reply object returned by <function>sd_bus_call()</function> or passed to the callback of
<function>sd_bus_call_async()</function>.</para>
<para>If <parameter>usec</parameter> is zero, the timeout set using
<citerefentry><refentrytitle>sd_bus_set_method_call_timeout</refentrytitle><manvolnum>3</manvolnum></citerefentry>
is used. If no method call timeout was set, the timeout is read from the
<varname>$SYSTEMD_BUS_TIMEOUT</varname> environment variable. If this environment variable is
unset or does not contain a valid timeout, the implementation falls back to a predefined method
call timeout of 25 seconds. Note that <varname>$SYSTEMD_BUS_TIMEOUT</varname> is read once and
cached so callers should not rely on being able to change the default method call timeout at
runtime by changing the value of <varname>$SYSTEMD_BUS_TIMEOUT</varname>. Instead, call
<function>sd_bus_set_method_call_timeout()</function> to change the default method call timeout.
</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>On success, these functions return a non-negative integer. On failure, they return a
negative errno-style error code.</para>
<refsect2 id='errors'>
<title>Errors</title>
<para>Returned errors may indicate the following problems:</para>
<variablelist>
<varlistentry>
<term><constant>-EINVAL</constant></term>
<listitem><para>The input parameter <parameter>m</parameter> is <constant>NULL</constant>.
</para></listitem>
<listitem><para>The input parameter <parameter>m</parameter> is not a D-Bus method call.
To create a new D-Bus method call, use
<citerefentry><refentrytitle>sd_bus_message_new_method_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para></listitem>
<listitem><para>The input parameter <parameter>m</parameter> has the
<constant>BUS_MESSAGE_NO_REPLY_EXPECTED</constant> flag set.</para></listitem>
<listitem><para>The input parameter <parameter>error</parameter> is
non-<constant>NULL</constant> but was not set to <constant>SD_BUS_ERROR_NULL</constant>.
</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ECHILD</constant></term>
<listitem><para>The bus connection was allocated in a parent process and is being reused
in a child process after <function>fork()</function>.</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENOTCONN</constant></term>
<listitem><para>The bus parameter <parameter>bus</parameter> is <constant>NULL</constant>
or the bus is not connected.</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ECONNRESET</constant></term>
<listitem><para>The client was disconnected while waiting for the response.
</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ETIMEDOUT</constant></term>
<listitem><para>A response was not received within the given timeout.</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ELOOP</constant></term>
<listitem><para>The message <parameter>m</parameter> is addressed to its own client.
</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENOMEM</constant></term>
<listitem><para>Memory allocation failed.</para></listitem>
</varlistentry>
</variablelist>
</refsect2>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<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_call_method</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_call_method_async</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_new_method_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>

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@ -20,7 +20,8 @@
<refname>sd_bus_call_method</refname>
<refname>sd_bus_call_method_async</refname>
<refpurpose>Invoke a D-Bus method call</refpurpose>
<refpurpose>Initialize a bus message object and invoke the corresponding D-Bus method call
</refpurpose>
</refnamediv>
<refsynopsisdiv>
@ -59,15 +60,15 @@
<refsect1>
<title>Description</title>
<para><function>sd_bus_call_method()</function> is a convenience function for calling a D-Bus
method. It combines the
<para><function>sd_bus_call_method()</function> is a convenience function for initializing a
bus message object and calling the corresponding D-Bus method. It combines the
<citerefentry><refentrytitle>sd_bus_message_new_method_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry> and
<citerefentry><refentrytitle>sd_bus_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>
functions into a single function call.</para>
<para><function>sd_bus_call_method_async()</function> is a convenience function for calling a
D-Bus method asynchronously. It combines the
<para><function>sd_bus_call_method_async()</function> is a convenience function for initializing
a bus message object and calling the corresponding D-Bus method asynchronously. It combines the
<citerefentry><refentrytitle>sd_bus_message_new_method_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry> and
<citerefentry><refentrytitle>sd_bus_call_async</refentrytitle><manvolnum>3</manvolnum></citerefentry>
@ -77,7 +78,7 @@
<refsect1>
<title>Return Value</title>
<para>On success, these functions returns a non-negative integer. On failure, they return a
<para>On success, these functions return a non-negative integer. On failure, they return a
negative errno-style error code.</para>
<refsect2 id='errors'>

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@ -84,7 +84,7 @@
<refsect1>
<title>Return Value</title>
<para>On success, these functions returns a non-negative integer. On failure, they return a
<para>On success, these functions return a non-negative integer. On failure, they return a
negative errno-style error code.</para>
<refsect2 id='errors'>
@ -163,8 +163,9 @@
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_call_method</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_path_encode</refentrytitle><manvolnum>3</manvolnum></citerefentry>
<citerefentry><refentrytitle>sd_bus_call_method</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>

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@ -63,7 +63,7 @@
pointers to appropriate types (a pointer to <type>int8_t</type> for a <literal>y</literal> in
the type string, a pointer to <type>int32_t</type> for an <literal>i</literal>, a pointer to
<type>const char*</type> for an <literal>s</literal>, ...) which are set based on the values in
the message. As an exception, in case or array and variant types, the first argument is an
the message. As an exception, in case of array and variant types, the first argument is an
"input" argument that further specifies how the message should be read. See the table below for
a complete list of allowed arguments and their types. Note that, if the basic type is a pointer
(e.g., <type>const char *</type> in the case of a string), the argument is a pointer to a