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Diffstat (limited to 'src/libsystemd/sd_bus_path_encode.xml')
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diff --git a/src/libsystemd/sd_bus_path_encode.xml b/src/libsystemd/sd_bus_path_encode.xml new file mode 100644 index 0000000000..3088243e45 --- /dev/null +++ b/src/libsystemd/sd_bus_path_encode.xml @@ -0,0 +1,188 @@ +<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> +<!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_path_encode"> + + <refentryinfo> + <title>sd_bus_path_encode</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_path_encode</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_bus_path_encode</refname> + <refname>sd_bus_path_encode_many</refname> + <refname>sd_bus_path_decode</refname> + <refname>sd_bus_path_decode_many</refname> + + <refpurpose>Convert an external identifier into an object path and back</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> + + <funcprototype> + <funcdef>int <function>sd_bus_path_encode</function></funcdef> + <paramdef>const char *<parameter>prefix</parameter></paramdef> + <paramdef>const char *<parameter>external_id</parameter></paramdef> + <paramdef>char **<parameter>ret_path</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_bus_path_encode_many</function></funcdef> + <paramdef>char **<parameter>out</parameter></paramdef> + <paramdef>const char *<parameter>path_template</parameter></paramdef> + <paramdef>...</paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_bus_path_decode</function></funcdef> + <paramdef>const char *<parameter>path</parameter></paramdef> + <paramdef>const char *<parameter>prefix</parameter></paramdef> + <paramdef>char **<parameter>ret_external_id</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_bus_path_decode_many</function></funcdef> + <paramdef>const char *<parameter>path</parameter></paramdef> + <paramdef>const char *<parameter>path_template</parameter></paramdef> + <paramdef>...</paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><function>sd_bus_path_encode()</function> and + <function>sd_bus_path_decode()</function> convert external + identifier strings into object paths and back. These functions are + useful to map application-specific string identifiers of any kind + into bus object paths in a simple, reversible and safe way.</para> + + <para><function>sd_bus_path_encode()</function> takes a bus path + prefix and an external identifier string as arguments, plus a + place to store the returned bus path string. The bus path prefix + must be a valid bus path, starting with a slash + <literal>/</literal>, and not ending in one. The external + identifier string may be in any format, may be the empty string, + and has no restrictions on the charset — however, it must + 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 + 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 + set), in order to ensure the resulting bus path is still short and + easily processed.</para> + + <para><function>sd_bus_path_decode()</function> reverses the + operation of <function>sd_bus_path_encode()</function> and thus + regenerates an external identifier string from a bus path. It + takes a bus path and a prefix string, plus a place to store the + returned external identifier string. If the bus path does not + start with the specified prefix, 0 is returned and the returned + string is set to <constant>NULL</constant>. Otherwise, the + string following the prefix is unescaped and returned in the + external identifier string.</para> + + <para>The escaping used will replace all characters which are + invalid in a bus object path by <literal>_</literal>, followed by a + hexadecimal value. As a special case, the empty string will be + replaced by a lone <literal>_</literal>.</para> + + <para><function>sd_bus_path_encode_many()</function> works like + its counterpart <function>sd_bus_path_encode()</function>, but + takes a path template as argument and encodes multiple labels + according to its embedded directives. For each + <literal>%</literal> character found in the template, the caller + must provide a string via varargs, which will be encoded and + embedded at the position of the <literal>%</literal> character. + Any other character in the template is copied verbatim into the + encoded path.</para> + + <para><function>sd_bus_path_decode_many()</function> does the + reverse of <function>sd_bus_path_encode_many()</function>. It + decodes the passed object path according to the given + path template. For each <literal>%</literal> character in the + template, the caller must provide an output storage + (<literal>char **</literal>) via varargs. The decoded label + will be stored there. Each <literal>%</literal> character will + only match the current label. It will never match across labels. + Furthermore, only a single directive is allowed per label. + If <literal>NULL</literal> is passed as output storage, the + label is verified but not returned to the caller.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, <function>sd_bus_path_encode()</function> + returns positive or 0, and a valid bus path in the return + argument. On success, <function>sd_bus_path_decode()</function> + returns a positive value if the prefixed matched, or 0 if it + did not. If the prefix matched, the external identifier is returned + in the return parameter. If it did not match, NULL is returned in + the return parameter. On failure, a negative errno-style error + number is returned by either function. The returned strings must + be + <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>'d + by the caller.</para> + </refsect1> + + <refsect1> + <title>Notes</title> + + <para><function>sd_bus_path_encode()</function> and + <function>sd_bus_path_decode()</function> are available as a + shared library, which can be compiled and linked to with the + <constant>libsystemd</constant> <citerefentry project='die-net'><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 project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |