diff options
| -rw-r--r-- | man/print-unit-path.c | 64 | ||||
| -rw-r--r-- | man/rules/meson.build | 1 | ||||
| -rw-r--r-- | man/sd-bus.xml | 1 | ||||
| -rw-r--r-- | man/sd_bus_message_new_method_call.xml | 134 | ||||
| -rw-r--r-- | man/sd_bus_message_new_signal.xml | 6 | ||||
| -rw-r--r-- | man/sd_bus_path_encode.xml | 2 |
6 files changed, 206 insertions, 2 deletions
diff --git a/man/print-unit-path.c b/man/print-unit-path.c new file mode 100644 index 0000000000..23b58a26e2 --- /dev/null +++ b/man/print-unit-path.c @@ -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); +} diff --git a/man/rules/meson.build b/man/rules/meson.build index df7ea47470..1c56e75fd4 100644 --- a/man/rules/meson.build +++ b/man/rules/meson.build @@ -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', diff --git a/man/sd-bus.xml b/man/sd-bus.xml index 6210f40dc2..5a3502601c 100644 --- a/man/sd-bus.xml +++ b/man/sd-bus.xml @@ -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>, diff --git a/man/sd_bus_message_new_method_call.xml b/man/sd_bus_message_new_method_call.xml new file mode 100644 index 0000000000..1226f1050c --- /dev/null +++ b/man/sd_bus_message_new_method_call.xml @@ -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> diff --git a/man/sd_bus_message_new_signal.xml b/man/sd_bus_message_new_signal.xml index 1c7629c149..c9ed0bc4a4 100644 --- a/man/sd_bus_message_new_signal.xml +++ b/man/sd_bus_message_new_signal.xml @@ -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> diff --git a/man/sd_bus_path_encode.xml b/man/sd_bus_path_encode.xml index 55c7010e73..4c60a8fa3e 100644 --- a/man/sd_bus_path_encode.xml +++ b/man/sd_bus_path_encode.xml @@ -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 |