mirror of
https://github.com/systemd/systemd.git
synced 2025-01-03 05:18:09 +03:00
man: add sd_bus_message_new_call(3)
This commit is contained in:
parent
e8b84fcca6
commit
cfe8ee463d
64
man/print-unit-path.c
Normal file
64
man/print-unit-path.c
Normal file
@ -0,0 +1,64 @@
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
#include <unistd.h>
|
||||
#include <sys/types.h>
|
||||
|
||||
#include <systemd/sd-bus.h>
|
||||
#define _cleanup_(f) __attribute__((cleanup(f)))
|
||||
|
||||
/* This is equivalent to:
|
||||
* busctl call org.freedesktop.systemd1 /org/freedesktop/systemd1 \
|
||||
* org.freedesktop.systemd1.Manager GetUnitByPID $$
|
||||
*
|
||||
* Compile with 'cc -lsystemd print-unit-path.c'
|
||||
*/
|
||||
|
||||
#define DESTINATION "org.freedesktop.systemd1"
|
||||
#define PATH "/org/freedesktop/systemd1"
|
||||
#define INTERFACE "org.freedesktop.systemd1.Manager"
|
||||
#define MEMBER "GetUnitByPID"
|
||||
|
||||
static int log_error(int error, const char *message) {
|
||||
fprintf(stderr, "%s: %s\n", message, strerror(-error));
|
||||
return error;
|
||||
}
|
||||
|
||||
static int print_unit_path(sd_bus *bus) {
|
||||
_cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
|
||||
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
|
||||
_cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
|
||||
int r;
|
||||
|
||||
r = sd_bus_message_new_method_call(bus, &m,
|
||||
DESTINATION, PATH, INTERFACE, MEMBER);
|
||||
if (r < 0)
|
||||
return log_error(r, "Failed to create bus message");
|
||||
|
||||
r = sd_bus_message_append(m, "u", (unsigned) getpid());
|
||||
if (r < 0)
|
||||
return log_error(r, "Failed to append to bus message");
|
||||
|
||||
r = sd_bus_call(bus, m, -1, &error, &reply);
|
||||
if (r < 0)
|
||||
return log_error(r, "Call failed");
|
||||
|
||||
const char *ans;
|
||||
r = sd_bus_message_read(reply, "o", &ans);
|
||||
if (r < 0)
|
||||
return log_error(r, "Failed to read reply");
|
||||
|
||||
printf("Unit path is \"%s\".\n", ans);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int main(int argc, char **argv) {
|
||||
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
|
||||
int r;
|
||||
|
||||
r = sd_bus_open_system(&bus);
|
||||
if (r < 0)
|
||||
return log_error(r, "Failed to acquire bus");
|
||||
|
||||
print_unit_path(bus);
|
||||
}
|
@ -210,6 +210,7 @@ manpages = [
|
||||
'3',
|
||||
['sd_bus_message_get_realtime_usec', 'sd_bus_message_get_seqnum'],
|
||||
''],
|
||||
['sd_bus_message_new_method_call', '3', [], ''],
|
||||
['sd_bus_message_new_method_error',
|
||||
'3',
|
||||
['sd_bus_message_new_method_errno',
|
||||
|
@ -60,6 +60,7 @@
|
||||
<citerefentry><refentrytitle>sd_bus_message_copy</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_message_get_cookie</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_message_get_monotonic_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_message_new_method_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_message_new_method_error</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_message_new_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
<citerefentry><refentrytitle>sd_bus_message_read_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||||
|
134
man/sd_bus_message_new_method_call.xml
Normal file
134
man/sd_bus_message_new_method_call.xml
Normal file
@ -0,0 +1,134 @@
|
||||
<?xml version='1.0'?>
|
||||
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
|
||||
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
||||
<!-- SPDX-License-Identifier: LGPL-2.1+ -->
|
||||
|
||||
<refentry id="sd_bus_message_new_method_call"
|
||||
xmlns:xi="http://www.w3.org/2001/XInclude">
|
||||
|
||||
<refentryinfo>
|
||||
<title>sd_bus_message_new_method_call</title>
|
||||
<productname>systemd</productname>
|
||||
</refentryinfo>
|
||||
|
||||
<refmeta>
|
||||
<refentrytitle>sd_bus_message_new_method_call</refentrytitle>
|
||||
<manvolnum>3</manvolnum>
|
||||
</refmeta>
|
||||
|
||||
<refnamediv>
|
||||
<refname>sd_bus_message_new_method_call</refname>
|
||||
|
||||
<refpurpose>Create a method call message</refpurpose>
|
||||
</refnamediv>
|
||||
|
||||
<refsynopsisdiv>
|
||||
<funcsynopsis>
|
||||
<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
|
||||
|
||||
<funcprototype>
|
||||
<funcdef>int sd_bus_message_new_method_call</funcdef>
|
||||
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
|
||||
<paramdef>sd_bus_message **<parameter>m</parameter></paramdef>
|
||||
<paramdef>const char *<parameter>destination</parameter></paramdef>
|
||||
<paramdef>const char *<parameter>path</parameter></paramdef>
|
||||
<paramdef>const char *<parameter>interface</parameter></paramdef>
|
||||
<paramdef>const char *<parameter>member</parameter></paramdef>
|
||||
</funcprototype>
|
||||
</funcsynopsis>
|
||||
</refsynopsisdiv>
|
||||
|
||||
<refsect1>
|
||||
<title>Description</title>
|
||||
|
||||
<para>The <function>sd_bus_message_new_method_call()</function> function creates a new bus
|
||||
message object that encapsulates a D-Bus method call, and returns it in the
|
||||
<parameter>m</parameter> output parameter. The call will be made on the destination
|
||||
<parameter>destination</parameter>, path <parameter>path</parameter>, on the interface
|
||||
<parameter>interface</parameter>, member <parameter>member</parameter>.</para>
|
||||
|
||||
<para>Briefly, the <emphasis>destination</emphasis> is a dot-separated name that identifies a
|
||||
service connected to the bus. The <emphasis>path</emphasis> is a slash-separated identifier of
|
||||
an object within the destination that resembles a file system path. The meaning of this path is
|
||||
defined by the destination. The <emphasis>interface</emphasis> is a dot-separated name that
|
||||
resembles a Java interface name that identifies a group of methods and signals supported by the
|
||||
object identified by path. Methods and signals are collectively called
|
||||
<emphasis>members</emphasis> and are identified by a simple name composed of ASCII letters,
|
||||
numbers, and underscores. See the <ulink
|
||||
url="https://dbus.freedesktop.org/doc/dbus-tutorial.html#concepts">D-Bus Tutorial</ulink> for an
|
||||
in-depth explanation.</para>
|
||||
|
||||
<para>The <parameter>destination</parameter> parameter may be <constant>NULL</constant>. The
|
||||
<parameter>interface</parameter> parameter may be <constant>NULL</constant>, if the destination
|
||||
has only a single member with the given name and there is no ambiguity if the interface name is
|
||||
omitted.</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>Return Value</title>
|
||||
|
||||
<para>This function returns 0 if the message object was successfully created, and a negative
|
||||
errno-style error code otherwise.</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1 id='errors'>
|
||||
<title>Errors</title>
|
||||
|
||||
<para>Returned errors may indicate the following problems:</para>
|
||||
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term><constant>-EINVAL</constant></term>
|
||||
|
||||
<listitem><para>The output parameter <parameter>m</parameter> is
|
||||
<constant>NULL</constant>.</para>
|
||||
|
||||
<para>The <parameter>destination</parameter> parameter is non-null and is not a valid D-Bus
|
||||
service name (<literal>org.somewhere.Something</literal>), the <parameter>path</parameter>
|
||||
parameter is not a valid D-Bus path (<literal>/an/object/path</literal>), the
|
||||
<parameter>interface</parameter> parameter is non-null and is not a valid D-Bus interface
|
||||
name (<literal>an.interface.name</literal>), or the <parameter>member</parameter> parameter
|
||||
is not a valid D-Bus member (<literal>Name</literal>).</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>-ENOMEM</constant></term>
|
||||
|
||||
<listitem><para>Memory allocation failed.</para></listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
</refsect1>
|
||||
|
||||
<xi:include href="libsystemd-pkgconfig.xml" />
|
||||
|
||||
<refsect1>
|
||||
<title>Examples</title>
|
||||
|
||||
<example>
|
||||
<title>Make a call to a D-Bus method that takes a single parameter</title>
|
||||
|
||||
<programlisting><xi:include href="print-unit-path.c" parse="text" /></programlisting>
|
||||
<para>This defines a minimally useful program that will open a connection to the bus, create a
|
||||
message object, send it, wait for the reply, and finally extract and print the answer. It does
|
||||
error handling and proper memory management.</para>
|
||||
</example>
|
||||
</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_path_encode</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
</refentry>
|
@ -44,7 +44,11 @@
|
||||
object that encapsulates a D-Bus signal, and returns it in the <parameter>m</parameter> output
|
||||
parameter. The signal will be sent to path <parameter>path</parameter>, on the interface
|
||||
<parameter>interface</parameter>, member <parameter>member</parameter>. When this message is
|
||||
sent, no reply is expected.</para>
|
||||
sent, no reply is expected. See
|
||||
<citerefentry><refentrytitle>sd_bus_message_new_call</refentrytitle><manvolnum>1</manvolnum></citerefentry>
|
||||
for a short description of the meaning of the <parameter>path</parameter>,
|
||||
<parameter>interface</parameter>, and <parameter>member</parameter> parameters.
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
|
@ -80,7 +80,7 @@
|
||||
always be <constant>NUL</constant>-terminated. The returned string
|
||||
will be the concatenation of the bus path prefix plus an escaped
|
||||
version of the external identifier string. This operation may be
|
||||
reversed with <function>sd_bus_decode()</function>. It is
|
||||
reversed with <function>sd_bus_path_decode()</function>. It is
|
||||
recommended to only use external identifiers that generally
|
||||
require little escaping to be turned into valid bus path
|
||||
identifiers (for example, by sticking to a 7-bit ASCII character
|
||||
|
Loading…
Reference in New Issue
Block a user