man/sd_path_lookup.xml

   1 <?xml version='1.0'?>
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
   5
   6 <refentry id="sd_path_lookup" xmlns:xi="http://www.w3.org/2001/XInclude">
   7
   8   <refentryinfo>
   9     <title>sd_path_lookup</title>
  10     <productname>systemd</productname>
  11   </refentryinfo>
  12
  13   <refmeta>
  14     <refentrytitle>sd_path_lookup</refentrytitle>
  15     <manvolnum>3</manvolnum>
  16   </refmeta>
  17
  18   <refnamediv>
  19     <refname>sd_path_lookup</refname>
  20     <refname>sd_path_lookup_strv</refname>
  21
  22     <refpurpose>Query well-known file system paths</refpurpose>
  23   </refnamediv>
  24
  25   <refsynopsisdiv>
  26     <funcsynopsis>
  27       <funcsynopsisinfo>#include &lt;systemd/sd-path.h&gt;</funcsynopsisinfo>
  28
  29       <!-- note: individual constants are not added as <refname>s, there's just too many -->
  30
  31       <funcsynopsisinfo><token>enum</token> {
  32         <constant>SD_PATH_TEMPORARY</constant>,
  33         <constant>SD_PATH_TEMPORARY_LARGE</constant>,
  34
  35         <constant>SD_PATH_SYSTEM_BINARIES</constant>,
  36         <constant>SD_PATH_SYSTEM_INCLUDE</constant>,
  37         <constant>SD_PATH_SYSTEM_LIBRARY_PRIVATE</constant>,
  38         <constant>SD_PATH_SYSTEM_LIBRARY_ARCH</constant>,
  39         <constant>SD_PATH_SYSTEM_SHARED</constant>,
  40         <constant>SD_PATH_SYSTEM_CONFIGURATION_FACTORY</constant>,
  41         <constant>SD_PATH_SYSTEM_STATE_FACTORY</constant>,
  42
  43         <constant>SD_PATH_SYSTEM_CONFIGURATION</constant>,
  44         <constant>SD_PATH_SYSTEM_RUNTIME</constant>,
  45         <constant>SD_PATH_SYSTEM_RUNTIME_LOGS</constant>,
  46         <constant>SD_PATH_SYSTEM_STATE_PRIVATE</constant>,
  47         <constant>SD_PATH_SYSTEM_STATE_LOGS</constant>,
  48         <constant>SD_PATH_SYSTEM_STATE_CACHE</constant>,
  49         <constant>SD_PATH_SYSTEM_STATE_SPOOL</constant>,
  50
  51         <constant>SD_PATH_USER_BINARIES</constant>,
  52         <constant>SD_PATH_USER_LIBRARY_PRIVATE</constant>,
  53         <constant>SD_PATH_USER_LIBRARY_ARCH</constant>,
  54         <constant>SD_PATH_USER_SHARED</constant>,
  55
  56         <constant>SD_PATH_USER_CONFIGURATION</constant>,
  57         <constant>SD_PATH_USER_RUNTIME</constant>,
  58         <constant>SD_PATH_USER_STATE_CACHE</constant>,
  59
  60         <constant>SD_PATH_USER</constant>,
  61         <constant>SD_PATH_USER_DOCUMENTS</constant>,
  62         <constant>SD_PATH_USER_MUSIC</constant>,
  63         <constant>SD_PATH_USER_PICTURES</constant>,
  64         <constant>SD_PATH_USER_VIDEOS</constant>,
  65         <constant>SD_PATH_USER_DOWNLOAD</constant>,
  66         <constant>SD_PATH_USER_PUBLIC</constant>,
  67         <constant>SD_PATH_USER_TEMPLATES</constant>,
  68         <constant>SD_PATH_USER_DESKTOP</constant>,
  69
  70         <constant>SD_PATH_SEARCH_BINARIES</constant>,
  71         <constant>SD_PATH_SEARCH_BINARIES_DEFAULT</constant>,
  72         <constant>SD_PATH_SEARCH_LIBRARY_PRIVATE</constant>,
  73         <constant>SD_PATH_SEARCH_LIBRARY_ARCH</constant>,
  74         <constant>SD_PATH_SEARCH_SHARED</constant>,
  75         <constant>SD_PATH_SEARCH_CONFIGURATION_FACTORY</constant>,
  76         <constant>SD_PATH_SEARCH_STATE_FACTORY</constant>,
  77         <constant>SD_PATH_SEARCH_CONFIGURATION</constant>,
  78
  79         <constant>SD_PATH_SYSTEMD_UTIL</constant>,
  80         <constant>SD_PATH_SYSTEMD_SYSTEM_UNIT</constant>,
  81         <constant>SD_PATH_SYSTEMD_SYSTEM_PRESET</constant>,
  82         <constant>SD_PATH_SYSTEMD_USER_UNIT</constant>,
  83         <constant>SD_PATH_SYSTEMD_USER_PRESET</constant>,
  84         <constant>SD_PATH_SYSTEMD_SYSTEM_CONF</constant>,
  85         <constant>SD_PATH_SYSTEMD_USER_CONF</constant>,
  86         <constant>SD_PATH_SYSTEMD_SEARCH_SYSTEM_UNIT</constant>,
  87         <constant>SD_PATH_SYSTEMD_SEARCH_USER_UNIT</constant>,
  88         <constant>SD_PATH_SYSTEMD_SYSTEM_GENERATOR</constant>,
  89         <constant>SD_PATH_SYSTEMD_USER_GENERATOR</constant>,
  90         <constant>SD_PATH_SYSTEMD_SEARCH_SYSTEM_GENERATOR</constant>,
  91         <constant>SD_PATH_SYSTEMD_SEARCH_USER_GENERATOR</constant>,
  92         <constant>SD_PATH_SYSTEMD_SLEEP</constant>,
  93         <constant>SD_PATH_SYSTEMD_SHUTDOWN</constant>,
  94
  95         <constant>SD_PATH_TMPFILES</constant>,
  96         <constant>SD_PATH_SYSUSERS</constant>,
  97         <constant>SD_PATH_SYSCTL</constant>,
  98         <constant>SD_PATH_BINFMT</constant>,
  99         <constant>SD_PATH_MODULES_LOAD</constant>,
 100         <constant>SD_PATH_CATALOG</constant>,
 101
 102         <constant>SD_PATH_SYSTEMD_SEARCH_NETWORK</constant>,
 103 };</funcsynopsisinfo>
 104
 105       <funcprototype>
 106         <funcdef>int <function>sd_path_lookup</function></funcdef>
 107         <paramdef>uint64_t <parameter>type</parameter></paramdef>
 108         <paramdef>const char *<parameter>suffix</parameter></paramdef>
 109         <paramdef>char **<parameter>paths</parameter></paramdef>
 110       </funcprototype>
 111
 112       <funcprototype>
 113         <funcdef>int <function>sd_path_lookup_strv</function></funcdef>
 114         <paramdef>uint64_t <parameter>type</parameter></paramdef>
 115         <paramdef>const char *<parameter>suffix</parameter></paramdef>
 116         <paramdef>char ***<parameter>paths</parameter></paramdef>
 117       </funcprototype>
 118     </funcsynopsis>
 119   </refsynopsisdiv>
 120
 121   <refsect1>
 122     <title>Description</title>
 123
 124     <para><function>sd_path_lookup()</function> and <function>sd_bus_path_lookup_strv()</function> return a
 125     single path or set of file system paths specified by the argument <parameter>type</parameter>. In case of
 126     <function>sd_path_lookup()</function> a single <constant>NUL</constant>-terminated string is returned.
 127     When <parameter>type</parameter> specifies a set of paths, they are concatenated using
 128     <literal>:</literal> as a separator (as is traditionally done for e.g. <varname>$PATH</varname> or
 129     <varname>$LD_LIBRARY_PATH</varname>). In case of <function>sd_path_lookup_strv()</function> a
 130     <constant>NULL</constant>-terminated array of strings is returned (strv). If suffix
 131     <parameter>suffix</parameter> is given, it is concatenated to each of the paths after a slash
 132     (<literal>/</literal>). All returned paths are absolute.</para>
 133
 134     <para>For paths which refer to user directories, the relevant XDG standard is followed, with support for
 135     environment variables like <varname>$XDG_DOCUMENTS_DIR</varname>, <varname>$XDG_DESKTOP_DIR</varname>,
 136     ..., and explicit configuration in <filename>/etc/xdg/user-dirs.conf</filename> or
 137     <filename>${XDG_CONFIG_HOME}/user-dirs.dirs</filename>. See
 138     <ulink url="https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html">
 139       XDG Base Directory Specification</ulink> for details.</para>
 140
 141     <para><citerefentry><refentrytitle>systemd-path</refentrytitle><manvolnum>1</manvolnum></citerefentry> is
 142     a wrapper around <function>sd_path_lookup()</function> and allows the same set of paths to be queried.
 143     </para>
 144   </refsect1>
 145
 146   <refsect1>
 147     <title>Return Value</title>
 148
 149     <para>On success, <function>sd_path_lookup()</function> and <function>sd_path_lookup_strv()</function>
 150     return a non-negative integer. On failure, a negative errno-style error number is returned by either
 151     function.</para>
 152
 153     <para>The returned string or string array (strv) must be
 154     <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>'d by the
 155     caller.</para>
 156
 157     <refsect2 id='errors'>
 158       <title>Errors</title>
 159
 160       <para>Returned errors may indicate the following problems:</para>
 161
 162       <variablelist>
 163         <varlistentry>
 164           <term><constant>-EOPNOTSUPP</constant></term>
 165
 166           <listitem><para>Unknown identifier <parameter>type</parameter>.</para></listitem>
 167         </varlistentry>
 168
 169         <varlistentry>
 170           <term><constant>-EINVAL</constant></term>
 171
 172           <listitem><para>Output argument is <constant>NULL</constant>.</para></listitem>
 173         </varlistentry>
 174
 175         <varlistentry>
 176           <term><constant>-ENXIO</constant></term>
 177
 178           <listitem><para>Query failed because of an undefined environment variable (e.g. for
 179           <constant>SD_PATH_USER_RUNTIME</constant> when <varname>$XDG_RUNTIME_DIR</varname> is not
 180           defined).</para></listitem>
 181         </varlistentry>
 182
 183         <varlistentry>
 184           <term><constant>-ENOMEM</constant></term>
 185
 186           <listitem><para>Memory allocation failed.</para></listitem>
 187         </varlistentry>
 188       </variablelist>
 189     </refsect2>
 190   </refsect1>
 191
 192   <refsect1>
 193     <title>Examples</title>
 194
 195     <refsect2>
 196       <title>Look up the location of ~/Documents</title>
 197
 198       <programlisting><xi:include href="path-documents.c" parse="text" /></programlisting>
 199       <para>Note that the default answer of <filename index='false'>$HOME/Documents</filename> may be
 200       overridden by <filename index='false'>user-dirs.conf</filename> or
 201       <varname>$XDG_DOCUMENTS_DIR</varname>.</para>
 202     </refsect2>
 203   </refsect1>
 204
 205   <xi:include href="libsystemd-pkgconfig.xml" />
 206
 207   <refsect1>
 208     <title>See Also</title>
 209
 210     <para>
 211       <citerefentry><refentrytitle>systemd-path</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 212     </para>
 213   </refsect1>
 214
 215 </refentry>