mirror of
https://github.com/systemd/systemd-stable.git
synced 2024-10-29 21:55:25 +03:00
416 lines
15 KiB
XML
416 lines
15 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
|
||
<!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 Zbigniew Jędrzejewski-Szmek
|
||
|
||
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_error">
|
||
|
||
<refentryinfo>
|
||
<title>sd_bus_error</title>
|
||
<productname>systemd</productname>
|
||
|
||
<authorgroup>
|
||
<author>
|
||
<contrib>A monkey with a typewriter</contrib>
|
||
<firstname>Zbigniew</firstname>
|
||
<surname>Jędrzejewski-Szmek</surname>
|
||
<email>zbyszek@in.waw.pl</email>
|
||
</author>
|
||
</authorgroup>
|
||
</refentryinfo>
|
||
|
||
<refmeta>
|
||
<refentrytitle>sd_bus_error</refentrytitle>
|
||
<manvolnum>3</manvolnum>
|
||
</refmeta>
|
||
|
||
<refnamediv>
|
||
<refname>sd_bus_error</refname>
|
||
<refname>sd_bus_error_free</refname>
|
||
<refname>sd_bus_error_set</refname>
|
||
<refname>sd_bus_error_set_const</refname>
|
||
<refname>sd_bus_error_set_errno</refname>
|
||
<refname>sd_bus_error_set_errnof</refname>
|
||
<refname>sd_bus_error_get_errno</refname>
|
||
<refname>sd_bus_error_copy</refname>
|
||
<refname>sd_bus_error_is_set</refname>
|
||
<refname>sd_bus_error_has_name</refname>
|
||
|
||
<refpurpose>sd-bus error handling</refpurpose>
|
||
</refnamediv>
|
||
|
||
<refsynopsisdiv>
|
||
<funcsynopsis>
|
||
<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
|
||
|
||
<funcsynopsisinfo>typedef struct {
|
||
const char *name;
|
||
const char *message;
|
||
...
|
||
} sd_bus_error;</funcsynopsisinfo>
|
||
|
||
<para>
|
||
<constant>SD_BUS_ERROR_MAKE_CONST(<replaceable>name</replaceable>, <replaceable>message</replaceable>)</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_NULL</constant>
|
||
</para>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_error_free</function></funcdef>
|
||
<paramdef>sd_bus_error *<parameter>e</parameter></paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_error_set</function></funcdef>
|
||
<paramdef>sd_bus_error *<parameter>e</parameter></paramdef>
|
||
<paramdef>const char *<parameter>name</parameter></paramdef>
|
||
<paramdef>const char *<parameter>message</parameter></paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_error_setf</function></funcdef>
|
||
<paramdef>sd_bus_error *<parameter>e</parameter></paramdef>
|
||
<paramdef>const char *<parameter>name</parameter></paramdef>
|
||
<paramdef>const char *<parameter>format</parameter></paramdef>
|
||
<paramdef>...</paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_error_set_const</function></funcdef>
|
||
<paramdef>sd_bus_error *<parameter>e</parameter></paramdef>
|
||
<paramdef>const char *<parameter>name</parameter></paramdef>
|
||
<paramdef>const char *<parameter>message</parameter></paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_error_set_errno</function></funcdef>
|
||
<paramdef>sd_bus_error *<parameter>e</parameter></paramdef>
|
||
<paramdef>int <parameter>error</parameter></paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_error_set_errnof</function></funcdef>
|
||
<paramdef>sd_bus_error *<parameter>e</parameter></paramdef>
|
||
<paramdef>int <parameter>error</parameter></paramdef>
|
||
<paramdef>const char *<parameter>format</parameter></paramdef>
|
||
<paramdef>...</paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_error_get_errno</function></funcdef>
|
||
<paramdef>const sd_bus_error *<parameter>e</parameter></paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_error_copy</function></funcdef>
|
||
<paramdef>sd_bus_error *<parameter>dst</parameter></paramdef>
|
||
<paramdef>const sd_bus_error *<parameter>e</parameter></paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_error_is_set</function></funcdef>
|
||
<paramdef>const sd_bus_error *<parameter>e</parameter></paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_error_has_name</function></funcdef>
|
||
<paramdef>const sd_bus_error *<parameter>e</parameter></paramdef>
|
||
<paramdef>const char *<parameter>name</parameter></paramdef>
|
||
</funcprototype>
|
||
</funcsynopsis>
|
||
|
||
<para>
|
||
<constant>SD_BUS_ERROR_FAILED</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_NO_MEMORY</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_SERVICE_UNKNOWN</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_NAME_HAS_NO_OWNER</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_NO_REPLY</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_IO_ERROR</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_BAD_ADDRESS</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_NOT_SUPPORTED</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_LIMITS_EXCEEDED</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_ACCESS_DENIED</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_AUTH_FAILED</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_NO_SERVER</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_TIMEOUT</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_NO_NETWORK</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_ADDRESS_IN_USE</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_DISCONNECTED</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_INVALID_ARGS</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_FILE_NOT_FOUND</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_FILE_EXISTS</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_UNKNOWN_METHOD</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_UNKNOWN_OBJECT</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_UNKNOWN_INTERFACE</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_UNKNOWN_PROPERTY</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_PROPERTY_READ_ONLY</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_UNIX_PROCESS_ID_UNKNOWN</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_INVALID_SIGNATURE</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_INCONSISTENT_MESSAGE</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_MATCH_RULE_NOT_FOUND</constant>
|
||
</para>
|
||
<para>
|
||
<constant>SD_BUS_ERROR_MATCH_RULE_INVALID</constant>
|
||
</para>
|
||
|
||
</refsynopsisdiv>
|
||
|
||
<refsect1>
|
||
<title>Description</title>
|
||
|
||
<para>The <structname>sd_bus_error</structname> structure carries
|
||
information for a <filename>sd-bus</filename> error.
|
||
Functions described below can be used to set and query fields in
|
||
this structure. The <structfield>name</structfield> field contains a
|
||
short identifier of an error. It should follow the rules for error
|
||
names described in the D-Bus specification, subsection <ulink
|
||
url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names">Valid
|
||
Names</ulink>. The <structfield>message</structfield> is a human
|
||
readable string describing the details. When no longer necessary,
|
||
resources held by this structure should be destroyed with
|
||
<function>sd_bus_error_free</function>.</para>
|
||
|
||
<para><function>sd_bus_error_set</function> will return an
|
||
errno-like negative value returned based on parameter
|
||
<parameter>name</parameter> (see
|
||
<citerefentry><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>).
|
||
Various well-known D-Bus errors are converted to specific values,
|
||
and the remaining ones to <constant>-ENXIO</constant>. Well-known
|
||
D-Bus error names are available as constants
|
||
<constant>SD_BUS_ERROR_FAILED</constant>, etc., listed above. If
|
||
<parameter>name</parameter> is <constant>NULL</constant>, it is
|
||
assumed that no error occured, and 0 is returned. This means that
|
||
this function may be conveniently used in a
|
||
<function>return</function> statement.</para>
|
||
|
||
<para>If <parameter>e</parameter> is not
|
||
<constant>NULL</constant>, <structfield>name</structfield> and
|
||
<structfield>message</structfield> in the
|
||
<structname>sd_bus_error</structname> structure
|
||
<parameter>e</parameter> points at will be filled in. As described above,
|
||
<parameter>name</parameter> may be <constant>NULL</constant>,
|
||
which is treated as no error. Parameter
|
||
<parameter>message</parameter> may also be
|
||
<constant>NULL</constant>, in which case no message is specified.
|
||
<function>sd_bus_error_set</function> will make internal copies of
|
||
specified strings.</para>
|
||
|
||
<para><function>sd_bus_error_setf</function> is similar to
|
||
<function>sd_bus_error_set</function>, but takes a
|
||
<citerefentry><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||
format string and corresponding arguments to generate
|
||
<structname>message</structname>.</para>
|
||
|
||
<para><function>sd_bus_error_set_const</function> is similar to
|
||
<function>sd_bus_error_set</function>, but string parameters are
|
||
not copied internally, and must remain valid for the lifetime of
|
||
<parameter>e</parameter>.</para>
|
||
|
||
<para><function>sd_bus_error_set_errno</function> will set
|
||
<structfield>name</structfield> based on an errno-like value.
|
||
<citerefentry><refentrytitle>strerror</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||
will be used to set <structfield>message</structfield>. Well-known
|
||
D-Bus error names will be used for <structfield>name</structfield>
|
||
if available, otherwise a name in the
|
||
<literal>System.Error</literal> namespace will be generated.
|
||
</para>
|
||
|
||
<para><function>sd_bus_error_set_errnof</function> is similar to
|
||
<function>sd_bus_error_set_errno</function>, but in addition to
|
||
<parameter>name</parameter>, takes a
|
||
<citerefentry><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||
format and corresponding arguments.
|
||
<structfield>name</structfield> will be generated from
|
||
<parameter>format</parameter> and the arguments.</para>
|
||
|
||
<para><function>sd_bus_error_get_errno</function> is will convert
|
||
<structname>e->name</structname> to an errno-like value using the
|
||
same rules as <function>sd_bus_error_set</function>. If
|
||
<parameter>e</parameter> is <constant>NULL</constant>, 0 will be
|
||
returned.</para>
|
||
|
||
<para><function>sd_bus_error_copy</function> will initialize
|
||
<parameter>dst</parameter> using the values in
|
||
<parameter>e</parameter>. If the strings in
|
||
<parameter>e</parameter> were set using
|
||
<function>sd_bus_set_error_const</function>, they will be shared.
|
||
Otherwise, they will be copied.</para>
|
||
|
||
<para><function>sd_bus_error_is_set</function> will return
|
||
<constant>true</constant> if <parameter>e</parameter> is
|
||
non-<constant>NULL</constant> and an error has been set,
|
||
<constant>false</constant> otherwise.</para>
|
||
|
||
<para><function>sd_bus_error_has_name</function> will return true
|
||
if <parameter>e</parameter> is non-<constant>NULL</constant> and
|
||
an error with the same <parameter>name</parameter> has been set,
|
||
<constant>false</constant> otherwise.</para>
|
||
|
||
<para><function>sd_bus_error_free</function> will destroy resources
|
||
held by <parameter>e</parameter>. The parameter itself will not
|
||
be deallocated, and must be
|
||
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>d
|
||
by the caller if necessary.</para>
|
||
</refsect1>
|
||
|
||
<refsect1>
|
||
<title>Return Value</title>
|
||
|
||
<para>Functions <function>sd_bus_error_set</function>,
|
||
<function>sd_bus_error_setf</function>,
|
||
<function>sd_bus_error_set_const</function>, when successful,
|
||
return the negative errno value corresponding to the
|
||
<parameter>name</parameter> parameter. Functions
|
||
<function>sd_bus_error_set_errno</function> and
|
||
<function>sd_bus_error_set_errnof</function>, when successful,
|
||
return the value of the <parameter>errno</parameter> parameter. If
|
||
an error occurs, one of the negative error values listed below
|
||
will be returned.</para>
|
||
|
||
<para><function>sd_bus_error_get_errno</function> returns
|
||
<constant>false</constant> when <parameter>e</parameter> is
|
||
<constant>NULL</constant>, and a positive errno value mapped from
|
||
<parameter>e->name</parameter> otherwise.</para>
|
||
|
||
<para><function>sd_bus_error_copy</function> returns 0 or a
|
||
positive integer on success, and one of the negative error values
|
||
listed below otherwise.</para>
|
||
|
||
<para><function>sd_bus_error_is_set</function> returns
|
||
<constant>true</constant> when <parameter>e</parameter> and
|
||
<parameter>e->name</parameter> are non-<constant>NULL</constant>,
|
||
<constant>false</constant> otherwise.</para>
|
||
|
||
<para><function>sd_bus_error_has_name</function> returns
|
||
<constant>true</constant> when <parameter>e</parameter> is
|
||
non-<constant>NULL</constant> and <parameter>e->name</parameter>
|
||
is equal to <parameter>name</parameter>,
|
||
<constant>false</constant> otherwise.</para>
|
||
</refsect1>
|
||
|
||
<refsect1>
|
||
<title>Reference ownership</title>
|
||
<para><structname>sd_bus_error</structname> is not reference
|
||
counted. Users should destroy resources held by it by calling
|
||
<function>sd_bus_error_free</function>.</para>
|
||
</refsect1>
|
||
|
||
<refsect1>
|
||
<title>Errors</title>
|
||
|
||
<para>Returned errors may indicate the following problems:</para>
|
||
|
||
<variablelist>
|
||
|
||
<varlistentry>
|
||
<term><varname>-EINVAL</varname></term>
|
||
|
||
<listitem><para>Error was already set in
|
||
<structname>sd_bus_error</structname> structure when one the
|
||
error-setting functions was called.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>-ENOMEM</varname></term>
|
||
|
||
<listitem><para>Memory allocation failed.</para></listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
</refsect1>
|
||
|
||
<refsect1>
|
||
<title>Notes</title>
|
||
|
||
<para><function>sd_bus_set_error()</function> and other functions
|
||
described here are available as a shared library, which can be
|
||
compiled and linked to with the
|
||
<constant>libsystemd</constant> <citerefentry><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>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>strerror</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||
</para>
|
||
</refsect1>
|
||
|
||
</refentry>
|