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<?xml version="1.0" encoding="ISO-8859-1"?>
<!--
-
- This file is part of the OpenLink Software Virtuoso Open-Source (VOS)
- project.
-
- Copyright (C) 1998-2018 OpenLink Software
-
- This project is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by the
- Free Software Foundation; only version 2 of the License, dated June 1991.
-
- This program 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
- General Public License for more details.
-
- You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-
-
-->
<refentry id="fn_os_chmod">
<refmeta>
<refentrytitle>os_chmod</refentrytitle>
<refmiscinfo>file</refmiscinfo>
</refmeta>
<refnamediv>
<refname>os_chmod</refname>
<refpurpose>changes the file access mode of a file</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis id="fsyn_os_chmod">
<funcprototype id="fproto_os_chmod">
<funcdef><function>os_chmod</function></funcdef>
<paramdef>in <parameter>path</parameter> varchar</paramdef>
<paramdef>in <parameter>new_mod</parameter> integer</paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 id="desc"><title>Description</title>
<para><function>os_chmod</function> set the file mode bits
by calling the system function chmod() with the arguments supplied.</para>
<para>Not all the host OSes support all the file modes. That's why the function
will not throw an SQL error if the function fails.</para>
<para>It will return DB NULL value when the function was called successfully
and the error message as a string if it failed.</para>
<para>In most OSes the mode is a bitmask, so one would usually use the
<function>file_stat</function> to get the current mode and
<function>bit_or</function>/<function>bit_xor</function> to make the new
mode.</para>
<para>Typical bit layout (from Linux 'man 2 chmod') is :
<simplelist>
<member>bit 0 (mask 1) - execute/search by others </member>
<member>bit 1 (mask 2) - write by others </member>
<member>bit 2 (mask 4) - read by others </member>
<member>bit 3 (mask 8) - execute/search by group </member>
<member>bit 4 (mask 16) - write by group </member>
<member>bit 5 (mask 32) - read by group </member>
<member>bit 6 (mask 64) - execute/search by owner </member>
<member>bit 7 (mask 128) - write by owner </member>
<member>bit 8 (mask 256) - read by owner </member>
<member>bit 9 (mask 512) - sticky bit </member>
<member>bit 10 (mask 1024) - set group ID on execution </member>
<member>bit 12 (mask 2048) - set user ID on execution </member>
</simplelist>
</para>
<para>The DirsAllowed and DirsDenied lists in Parameters section of the
virtuoso configuration file (virtuoso.ini by default) are used to control
disk access. </para>
</refsect1>
<refsect1 id="params"><title>Parameters</title>
<refsect2><title>path</title>
<para><type>varchar</type> relative path.</para>
</refsect2>
<refsect2><title>new_mod</title>
<para><type>integer</type> new mode for the file.</para>
</refsect2>
</refsect1>
<refsect1 id="examples"><title>Examples</title>
<example id="ex_os_chmod"><title>Simple example</title>
<para>Make the virtuoso INI file readable by the others</para>
<screen>
SQL>select os_chmod (virtuoso_ini_path(), bit_or (cast (file_stat (virtuoso_ini_path(), 2) as integer), 4));
callret
VARCHAR
_______________________________________________________________________________
NULL
</screen>
</example>
</refsect1>
<refsect1 id="seealso"><title>See Also</title>
<para><link linkend="fn_file_delete"><function>file_delete</function></link></para>
<para><link linkend="fn_file_stat"><function>file_stat</function></link></para>
<para><link linkend="fn_os_chown"><function>os_chown</function></link></para>
<para><link linkend="fn_virtuoso_ini_path"><function>virtuoso_ini_path</function></link></para>
<para><link linkend="fn_bit_or"><function>bit_or</function></link></para>
<para><link linkend="fn_bit_xor"><function>bit_xor</function></link></para>
</refsect1>
</refentry>
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