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<refentry id="runkit.sandbox">
 <refnamediv>
  <refname>Runkit_Sandbox</refname>
  <refpurpose>
   Runkit Sandbox Class -- PHP Virtual Machine
  </refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;

  <para>
   Instantiating the <classname>Runkit_Sandbox</classname>
   class creates a new thread with its own scope
   and program stack.  Using a set of options passed to the constructor, this environment
   may be restricted to a subset of what the primary interpreter can do and provide a
   safer environment for executing user supplied code.
  </para>

  &note.runkit.sandbox;
 </refsect1>

 <refsect1 role="constructor">
  <title>Constructor</title>
  <methodsynopsis>
   <type>void</type><methodname>Runkit_Sandbox::__construct</methodname>
   <methodparam choice="opt"><type>array</type><parameter>options</parameter></methodparam>
  </methodsynopsis>

  <para>
   <parameter>options</parameter> is an associative array containing
   any combination of the special ini options listed below.
  </para>

  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>safe_mode</parameter></term>
     <listitem>
      <para>
       If the outer script which is instantiating the
       <classname>Runkit_Sandbox</classname> class
       is configured with <literal>safe_mode = off</literal>, then safe_mode
       may be turned on for the sandbox environment.  This setting can not
       be used to disable <literal>safe_mode</literal> when it's already
       enabled in the outer script.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>safe_mode_gid</parameter></term>
     <listitem>
      <para>
       If the outer script which is instantiating the
       <classname>Runkit_Sandbox</classname> class
       is configured with <literal>safe_mode_gid = on</literal>, then safe_mode_gid
       may be turned off for the sandbox environment.  This setting can not
       be used to enable <literal>safe_mode_gid</literal> when it's already
       disabled in the outer script.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>safe_mode_include_dir</parameter></term>
     <listitem>
      <para>
       If the outer script which is instantiating the
       <classname>Runkit_Sandbox</classname> class
       is configured with a <literal>safe_mode_include_dir</literal>,
       then a new safe_mode_include_dir may be set for sandbox environments
       below the currently defined value.  safe_mode_include_dir may also be
       cleared to indicate that the bypass feature is disabled.
       If safe_mode_include_dir was blank in the outer script, but safe_mode
       was not enabled, then any arbitrary safe_mode_include_dir may be set
       while turning safe_mode on.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>open_basedir</parameter></term>
     <listitem>
      <para>
       <parameter>open_basedir</parameter> may be set to any path below the
       current setting of <literal>open_basedir</literal>. If
       <literal>open_basedir</literal> is not set within the global scope,
       then it is assumed to be the root directory and may be set to any location.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>allow_url_fopen</parameter></term>
     <listitem>
      <para>
       Like <parameter>safe_mode</parameter>, this setting can only be made more restrictive,
       in this case by setting it to &false; when it is previously set to &true;
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>disable_functions</parameter></term>
     <listitem>
      <para>
       Comma separated list of functions to disable within the sandbox sub-interpreter.
       This list need not contain the names of the currently disabled functions,
       they will remain disabled whether listed here or not.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>disable_classes</parameter></term>
     <listitem>
      <para>
       Comma separated list of classes to disable within the sandbox sub-interpreter.
       This list need not contain the names of the currently disabled classes,
       they will remain disabled whether listed here or not.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>runkit.superglobal</parameter></term>
     <listitem>
      <para>
       Comma separated list of variables to be treated as superglobals within the
       sandbox sub-interpreter.  These variables will be used in addition to any
       variables defined internally or through the global runkit.superglobal setting.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>runkit.internal_override</parameter></term>
     <listitem>
      <para>
       Ini option <literal>runkit.internal_override</literal> may be disabled
       (but not re-enabled) within sandboxes.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>

  <example>
   <title>Instantiating a restricted sandbox</title>
   <programlisting role="php">
<![CDATA[
<?php
$options = array(
  'safe_mode'=>true,
  'open_basedir'=>'/var/www/users/jdoe/',
  'allow_url_fopen'=>'false',
  'disable_functions'=>'exec,shell_exec,passthru,system',
  'disable_classes'=>'myAppClass');
$sandbox = new Runkit_Sandbox($options);
/* Non-protected ini settings may set normally */
$sandbox->ini_set('html_errors',true);
?>
]]>
   </programlisting>
  </example>
 </refsect1>

 <refsect1 role="variables">
  <title>Accessing Variables</title>
  <para>
   All variables in the global scope of the sandbox environment
   are accessible as properties of the sandbox object.
   The first thing to note is that because of the way memory
   between these two threads is managed, object and resource
   variables can not currently be exchanged between interpreters.
   Additionally, all arrays are deep copied and any references
   will be lost.  This also means that references between
   interpreters are not possible.
  </para>

  <example>
   <title>Working with variables in a sandbox</title>
   <programlisting role="php">
<![CDATA[
<?php
$sandbox = new Runkit_Sandbox();

$sandbox->foo = 'bar';
$sandbox->eval('echo "$foo\n"; $bar = $foo . "baz";');
echo "{$sandbox->bar}\n";
if (isset($sandbox->foo)) unset($sandbox->foo);
$sandbox->eval('var_dump(isset($foo));');
?>
]]>
   </programlisting>
  </example>
  &example.outputs;
  <screen>
<![CDATA[
bar
barbaz
bool(false)
]]>
  </screen>
 </refsect1>

 <refsect1 role="functions">
  <title>Calling PHP Functions</title>
  <para>
   Any function defined within the sandbox may be called as
   a method on the sandbox object.  This also includes a few
   pseudo-function language constructs:  <function>eval</function>,
   <function>include</function>, <function>include_once</function>,
   <function>require</function>, <function>require_once</function>,
   <function>echo</function>, <function>print</function>,
   <function>die</function>, and <function>exit</function>.
  </para>

  <example>
   <title>Calling sandbox functions</title>
   <programlisting role="php">
<![CDATA[
<?php
$sandbox = new Runkit_Sandbox();

echo $sandbox->str_replace('a','f','abc');
?>
]]>
   </programlisting>
  </example>
  &example.outputs;
  <screen>
<![CDATA[
fbc
]]>
  </screen>

  <para>
   When passing arguments to a sandbox function, the arguments
   are taken from the outer instance of PHP.  If you wish to pass
   arguments from the sandbox's scope, be sure to access them as
   properties of the sandbox object as illustrated above.
  </para>

  <example>
   <title>Passing arguments to sandbox functions</title>
   <programlisting role="php">
<![CDATA[
<?php
$sandbox = new Runkit_Sandbox();

$foo = 'bar';
$sandbox->foo = 'baz';
echo $sandbox->str_replace('a',$foo,'a');
echo $sandbox->str_replace('a',$sandbox->foo,'a');
?>
]]>
   </programlisting>
  </example>
  &example.outputs;
  <screen>
<![CDATA[
bar
baz
]]>
  </screen>
 </refsect1>

 <refsect1 role="settings">
  <title>Changing Sandbox Settings</title>
  <para>
   As of runkit version 0.5, certain Sandbox settings may
   be modified on the fly using ArrayAccess syntax.
   Some settings, such as <parameter>active</parameter>
   are read-only and meant to provide status information.
   Other settings, such as <parameter>output_handler</parameter>
   may be set and read much like a normal array offset.
   Future settings may be write-only, however no such
   settings currently exist.
  </para>

  <para>
   <table>
    <title>Sandbox Settings / Status Indicators</title>
    <tgroup cols="4">
     <thead>
      <row>
       <entry>Setting</entry>
       <entry>Type</entry>
       <entry>Purpose</entry>
       <entry>Default</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry><literal>active</literal></entry>
       <entry><type>Boolean</type> (Read Only)</entry>
       <entry>
        &true; if the Sandbox is still in a usable state,
        &false; if the request is in bailout due to a
        call to die(), exit(), or because of a fatal
        error condition.
       </entry>
       <entry>&true; (Initial)</entry>
      </row>
      <row>
       <entry><literal>output_handler</literal></entry>
       <entry><type>Callback</type></entry>
       <entry>
        When set to a valid callback, all output generated
        by the Sandbox instance will be processed through
        the named function.
        Sandbox output handlers follow the same calling
        conventions as the system-wide output handler.
       </entry>
       <entry>None</entry>
      </row>
      <row>
       <entry><literal>parent_access</literal></entry>
       <entry><type>Boolean</type></entry>
       <entry>
        May the sandbox use instances of the
        <classname>Runkit_Sandbox_Parent</classname> class?
        Must be enabled for other
        <classname>Runkit_Sandbox_Parent</classname>
        related settings to work.
       </entry>
       <entry>&false;</entry>
      </row>
      <row>
       <entry><literal>parent_read</literal></entry>
       <entry><type>Boolean</type></entry>
       <entry>
        May the sandbox read variables in its parent's context?
       </entry>
       <entry>&false;</entry>
      </row>
      <row>
       <entry><literal>parent_write</literal></entry>
       <entry><type>Boolean</type></entry>
       <entry>
        May the sandbox modify variables in its parent's context?
       </entry>
       <entry>&false;</entry>
      </row>
      <row>
       <entry><literal>parent_eval</literal></entry>
       <entry><type>Boolean</type></entry>
       <entry>
        May the sandbox evaluate arbitrary code in its
        parent's context? <emphasis>DANGEROUS</emphasis>
       </entry>
       <entry>&false;</entry>
      </row>
      <row>
       <entry><literal>parent_include</literal></entry>
       <entry><type>Boolean</type></entry>
       <entry>
        May the sandbox include php code files in its
        parent's context? <emphasis>DANGEROUS</emphasis>
       </entry>
       <entry>&false;</entry>
      </row>
      <row>
       <entry><literal>parent_echo</literal></entry>
       <entry><type>Boolean</type></entry>
       <entry>
        May the sandbox echo data in its parent's context
        effectively bypassing its own output_handler?
       </entry>
       <entry>&false;</entry>
      </row>
      <row>
       <entry><literal>parent_call</literal></entry>
       <entry><type>Boolean</type></entry>
       <entry>
        May the sandbox call functions in its
        parent's context?
       </entry>
       <entry>&false;</entry>
      </row>
      <row>
       <entry><literal>parent_die</literal></entry>
       <entry><type>Boolean</type></entry>
       <entry>
        May the sandbox kill its own parent? (And thus itself)
       </entry>
       <entry>&false;</entry>
      </row>
      <row>
       <entry><literal>parent_scope</literal></entry>
       <entry><type>Integer</type></entry>
       <entry>
        What scope will parental property access look at?
        0 == Global scope, 1 == Calling scope,
        2 == Scope preceeding calling scope,
        3 == The scope before that, etc..., etc...
       </entry>
       <entry><literal>0</literal> (Global)</entry>
      </row>
      <row>
       <entry><literal>parent_scope</literal></entry>
       <entry><type>String</type></entry>
       <entry>
        When <literal>parent_scope</literal> is set to
        a string value, it refers to a named array variable
        in the global scope.  If the named variable does not
        exist at the time of access it will be created as an
        empty array.  If the variable exists but it not an array,
        a dummy array will be created containing a reference
        to the named global variable.
       </entry>
       <entry></entry>
      </row>
     </tbody>
    </tgroup>
   </table>
  </para>
 </refsect1>

</refentry>

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