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diff --git a/rubbos/app/apache2/manual/developer/debugging.html.en b/rubbos/app/apache2/manual/developer/debugging.html.en new file mode 100644 index 00000000..3febd64c --- /dev/null +++ b/rubbos/app/apache2/manual/developer/debugging.html.en @@ -0,0 +1,196 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>Debugging Memory Allocation in APR - Apache HTTP Server</title> +<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> +<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> +<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /> +<link href="../images/favicon.ico" rel="shortcut icon" /></head> +<body id="manual-page"><div id="page-header"> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p> +<p class="apache">Apache HTTP Server Version 2.0</p> +<img alt="" src="../images/feather.gif" /></div> +<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> +<div id="path"> +<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.0</a> > <a href="./">Developer Documentation</a></div><div id="page-content"><div id="preamble"><h1>Debugging Memory Allocation in APR</h1> +<div class="toplang"> +<p><span>Available Languages: </span><a href="../en/developer/debugging.html" title="English"> en </a></p> +</div> + + <p>The allocation mechanism's within APR have a number of debugging modes + that can be used to assist in finding memory problems. This document + describes the modes available and gives instructions on activating + them.</p> +</div> +<div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#options">Available debugging options</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#combo">Allowable Combinations</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#howto">Activating Debugging Options</a></li> +</ul></div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="options" id="options">Available debugging options</a></h2> + <h3><a name="alloc_debug" id="alloc_debug">Allocation Debugging - ALLOC_DEBUG</a></h3> + + + <div class="note">Debugging support: Define this to enable code which + helps detect re-use of <code>free()</code>d memory and other such + nonsense.</div> + + <p>The theory is simple. The <code>FILL_BYTE</code> (<code>0xa5</code>) + is written over all <code>malloc</code>'d memory as we receive it, and + is written over everything that we free up during a + <code>clear_pool</code>. We check that blocks on the free list always + have the <code>FILL_BYTE</code> in them, and we check during + <code>palloc()</code> that the bytes still have <code>FILL_BYTE</code> + in them. If you ever see garbage URLs or whatnot containing lots + of <code>0xa5</code>s then you know something used data that's been + freed or uninitialized.</p> + + + <h3><a name="alloc_use_malloc" id="alloc_use_malloc">Malloc Support - ALLOC_USE_MALLOC</a></h3> + + + <div class="note">If defined all allocations will be done with + <code>malloc()</code> and <code>free()</code>d appropriately at the + end.</div> + + <p>This is intended to be used with something like Electric + Fence or Purify to help detect memory problems. Note that if + you're using efence then you should also add in <code>ALLOC_DEBUG</code>. + But don't add in <code>ALLOC_DEBUG</code> if you're using Purify because + <code>ALLOC_DEBUG</code> would hide all the uninitialized read errors + that Purify can diagnose.</p> + + + <h3><a name="pool_debug" id="pool_debug">Pool Debugging - POOL_DEBUG</a></h3> + <div class="note">This is intended to detect cases where the wrong pool is + used when assigning data to an object in another pool.</div> + + <p>In particular, it causes the <code>table_{set,add,merge}n</code> + routines to check that their arguments are safe for the + <code>apr_table_t</code> they're being placed in. It currently only works + with the unix multiprocess model, but could be extended to others.</p> + + + <h3><a name="make_table_profile" id="make_table_profile">Table Debugging - MAKE_TABLE_PROFILE</a></h3> + + + <div class="note">Provide diagnostic information about make_table() calls + which are possibly too small.</div> + + <p>This requires a recent gcc which supports + <code>__builtin_return_address()</code>. The error_log output will be a + message such as:</p> + <div class="example"><p><code> + table_push: apr_table_t created by 0x804d874 hit limit of 10 + </code></p></div> + + <p>Use <code>l *0x804d874</code> to find the + source that corresponds to. It indicates that a <code>apr_table_t</code> + allocated by a call at that address has possibly too small an + initial <code>apr_table_t</code> size guess.</p> + + + <h3><a name="alloc_stats" id="alloc_stats">Allocation Statistics - ALLOC_STATS</a></h3> + + + <div class="note">Provide some statistics on the cost of allocations.</div> + + <p>This requires a bit of an understanding of how alloc.c works.</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="combo" id="combo">Allowable Combinations</a></h2> + + <p>Not all the options outlined above can be activated at the + same time. the following table gives more information.</p> + + <table class="bordered"><tr class="header"><th /> + <th>ALLOC DEBUG</th> + <th>ALLOC USE MALLOC</th> + <th>POOL DEBUG</th> + <th>MAKE TABLE PROFILE</th> + <th>ALLOC STATS</th></tr> +<tr><th>ALLOC DEBUG</th> + <td>-</td><td>No</td><td>Yes</td><td>Yes</td><td>Yes</td></tr> +<tr class="odd"><th>ALLOC USE MALLOC</th> + <td>No</td><td>-</td><td>No</td><td>No</td><td>No</td></tr> +<tr><th>POOL DEBUG</th> + <td>Yes</td><td>No</td><td>-</td><td>Yes</td><td>Yes</td></tr> +<tr class="odd"><th>MAKE TABLE PROFILE</th> + <td>Yes</td><td>No</td><td>Yes</td><td>-</td><td>Yes</td></tr> +<tr><th>ALLOC STATS</th> + <td>Yes</td><td>No</td><td>Yes</td><td>Yes</td><td>-</td></tr> +</table> + + <p>Additionally the debugging options are not suitable for + multi-threaded versions of the server. When trying to debug + with these options the server should be started in single + process mode.</p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="howto" id="howto">Activating Debugging Options</a></h2> + + <p>The various options for debugging memory are now enabled in + the <code>apr_general.h</code> header file in APR. The various options are + enabled by uncommenting the define for the option you wish to + use. The section of the code currently looks like this + (<em>contained in srclib/apr/include/apr_pools.h</em>)</p> + + <div class="example"><p><code> + /*<br /> + #define ALLOC_DEBUG<br /> + #define POOL_DEBUG<br /> + #define ALLOC_USE_MALLOC<br /> + #define MAKE_TABLE_PROFILE<br /> + #define ALLOC_STATS<br /> + */<br /> + <br /> + typedef struct ap_pool_t {<br /> + <span class="indent"> + union block_hdr *first;<br /> + union block_hdr *last;<br /> + struct cleanup *cleanups;<br /> + struct process_chain *subprocesses;<br /> + struct ap_pool_t *sub_pools;<br /> + struct ap_pool_t *sub_next;<br /> + struct ap_pool_t *sub_prev;<br /> + struct ap_pool_t *parent;<br /> + char *free_first_avail;<br /> + </span> + #ifdef ALLOC_USE_MALLOC<br /> + <span class="indent"> + void *allocation_list;<br /> + </span> + #endif<br /> + #ifdef POOL_DEBUG<br /> + <span class="indent"> + struct ap_pool_t *joined;<br /> + </span> + #endif<br /> + <span class="indent"> + int (*apr_abort)(int retcode);<br /> + struct datastruct *prog_data;<br /> + </span> + } ap_pool_t; + </code></p></div> + + <p>To enable allocation debugging simply move the <code>#define + ALLOC_DEBUG</code> above the start of the comments block and rebuild + the server.</p> + + <div class="note"><h3>Note</h3> + <p>In order to use the various options the server <strong>must</strong> + be rebuilt after editing the header file.</p> + </div> +</div></div> +<div class="bottomlang"> +<p><span>Available Languages: </span><a href="../en/developer/debugging.html" title="English"> en </a></p> +</div><div id="footer"> +<p class="apache">Copyright 2009 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div> +</body></html>
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