man: document sd-bus error functions

1 files changed, 414 insertions, 0 deletions

diff --git a/man/sd_bus_error.xml b/man/sd_bus_error.xml
new file mode 100644
index 0000000000..38bc30311b
--- /dev/null
+++ b/man/sd_bus_error.xml
@@ -0,0 +1,414 @@
+<?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>libsystemd-bus error handling</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <funcsynopsis>
+      <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</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><structname>sd_bus_error</structname> structure carries
+    information for a <filename>libsystemd-bus</filename> error.
+    Functions described below can be used to set and query fields in
+    this structure. Field <structfield>name</structfield> 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 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> will be filled-in in the
+    <structname>sd_bus_error</structname> structure
+    <parameter>e</parameter> points at. 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>.
+    </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.
+    Otherwie they wil 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-bus</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>