+++ /dev/null
-<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
- "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
-
-<html xmlns="http://www.w3.org/1999/xhtml">
- <head>
- <meta name="generator" content="HTML Tidy, see www.w3.org" />
-
- <title>Debugging Memory Allocation in APR</title>
- </head>
- <!-- Background white, links blue (unvisited), navy (visited), red (active) -->
-
- <body bgcolor="#FFFFFF" text="#000000" link="#0000FF"
- vlink="#000080" alink="#FF0000">
- <!--#include virtual="header.html" -->
-
- <h1 align="center">Debugging Memory Allocation in APR<br />
- </h1>
-
- <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>
-
- <ul>
- <li><a href="#options">Available debugging options</a></li>
-
- <li><a href="#combo">Allowable combinations</a></li>
-
- <li><a href="#howto">How to activate debugging</a></li>
- </ul>
- <hr />
-
- <h2>Allocation Debugging</h2>
-
- <h3>ALLOC_DEBUG</h3>
-
- <p><em>Debugging support: Define this to enable code which
- helps detect re-use of freed memory and other such
- nonsense.</em></p>
-
- <p>The theory is simple. The FILL_BYTE (0xa5) is written over
- all malloc'd memory as we receive it, and is written over
- everything that we free up during a clear_pool. We check that
- blocks on the free list always have the FILL_BYTE in them, and
- we check during palloc() that the bytes still have FILL_BYTE in
- them. If you ever see garbage URLs or whatnot containing lots
- of 0xa5s then you know something used data that's been freed or
- uninitialized.</p>
-
- <h2>Malloc Support</h2>
-
- <h3>ALLOC_USE_MALLOC</h3>
-
- <p><em>If defined all allocations will be done with malloc and
- free()d appropriately at the end.</em></p>
-
- <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 ALLOC_DEBUG.
- But don't add in ALLOC_DEBUG if you're using Purify because
- ALLOC_DEBUG would hide all the uninitialized read errors that
- Purify can diagnose.</p>
-
- <h2>Pool Debugging</h2>
-
- <h3>POOL_DEBUG</h3>
-
- <p><em>This is intended to detect cases where the wrong pool is
- used when assigning data to an object in another pool.</em></p>
-
- <p>In particular, it causes the table_{set,add,merge}n routines
- to check that their arguments are safe for the apr_table_t
- they're being placed in. It currently only works with the unix
- multiprocess model, but could be extended to others.</p>
-
- <h2>Table Debugging</h2>
-
- <h3>MAKE_TABLE_PROFILE</h3>
-
- <p><em>Provide diagnostic information about make_table() calls
- which are possibly too small.</em></p>
-
- <p>This requires a recent gcc which supports
- __builtin_return_address(). The error_log output will be a
- message such as:</p>
-<pre>
-table_push: apr_table_t created by 0x804d874 hit limit of 10
-</pre>
-
- <p>Use "<em><strong>l *0x804d874</strong></em>" to find the
- source that corresponds to. It indicates that a apr_table_t
- allocated by a call at that address has possibly too small an
- initial apr_table_t size guess.</p>
-
- <h2>Allocation Statistics</h2>
-
- <h3>ALLOC_STATS</h3>
-
- <p><em>Provide some statistics on the cost of
- allocations.</em></p>
-
- <p>This requires a bit of an understanding of how alloc.c
- works.</p>
- <hr />
-
- <h2>Allowable Combinations</h2>
-
- <p>Not all the options outlined above can be activated at the
- same time. the following table gives more information.</p>
-
- <table width="80%">
- <tr>
- <th width="25%">Option 1</th>
-
- <th width="15%">ALLOC<br />
- DEBUG</th>
-
- <th width="15%">ALLOC<br />
- USE<br />
- MALLOC</th>
-
- <th width="15%">POOL<br />
- DEBUG</th>
-
- <th width="15%">MAKE<br />
- TABLE<br />
- PROFILE</th>
-
- <th width="15%">ALLOC<br />
- STATS</th>
- </tr>
-
- <tr>
- <td>ALLOC_DEBUG</td>
-
- <td bgcolor="#ff0000"> </td>
-
- <td align="center">No</td>
-
- <td align="center">Yes</td>
-
- <td align="center">Yes</td>
-
- <td align="center">Yes</td>
- </tr>
-
- <tr>
- <td>ALLOC_USE<br />
- MALLOC</td>
-
- <td align="center">No</td>
-
- <td bgcolor="#ff0000"> </td>
-
- <td align="center">No</td>
-
- <td align="center">No</td>
-
- <td align="center">No</td>
- </tr>
-
- <tr>
- <td>POOL_DEBUG</td>
-
- <td align="center">Yes</td>
-
- <td align="center">No</td>
-
- <td bgcolor="#ff0000"> </td>
-
- <td align="center">Yes</td>
-
- <td align="center">Yes</td>
- </tr>
-
- <tr>
- <td>MAKE_TABLE<br />
- PROFILE</td>
-
- <td align="center">Yes</td>
-
- <td align="center">No</td>
-
- <td align="center">Yes</td>
-
- <td bgcolor="#ff0000"> </td>
-
- <td align="center">Yes</td>
- </tr>
-
- <tr>
- <td>ALLOC_STATS</td>
-
- <td align="center">Yes</td>
-
- <td align="center">No</td>
-
- <td align="center">Yes</td>
-
- <td align="center">Yes</td>
-
- <td bgcolor="#ff0000"> </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>
- <hr />
-
- <h2>Activating Debugging Options</h2>
-
- <p>The various options for debugging memory are now enabled in
- the apr_general.h 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>
-<pre>
-/*
-#define ALLOC_DEBUG
-#define POOL_DEBUG
-#define ALLOC_USE_MALLOC
-#define MAKE_TABLE_PROFILE
-#define ALLOC_STATS
-*/
-
-typedef struct ap_pool_t {
- union block_hdr *first;
- union block_hdr *last;
- struct cleanup *cleanups;
- struct process_chain *subprocesses;
- struct ap_pool_t *sub_pools;
- struct ap_pool_t *sub_next;
- struct ap_pool_t *sub_prev;
- struct ap_pool_t *parent;
- char *free_first_avail;
-#ifdef ALLOC_USE_MALLOC
- void *allocation_list;
-#endif
-#ifdef POOL_DEBUG
- struct ap_pool_t *joined;
-#endif
- int (*apr_abort)(int retcode);
- struct datastruct *prog_data;
-}ap_pool_t;
-</pre>
-
- <p>To enable allocation debugging simply move the #define
- ALLOC_DEBUG above the start of the comments block and rebuild
- the server.</p>
- <strong>NB. In order to use the various options the server MUST
- be rebuilt after editing the header file.</strong>
- <!--#include virtual="footer.html" -->
- </body>
-</html>
-
--- /dev/null
+<?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 2.1</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-project/">Documentation</a> > <a href="../">Version 2.1</a></div><div id="page-content"><div id="preamble"><h1>Debugging Memory Allocation in APR</h1>
+ <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 id="footer">
+<p class="apache">Maintained by the <a href="http://httpd.apache.org/docs-project/">Apache HTTP Server Documentation Project</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>
\ No newline at end of file
--- /dev/null
+<?xml version="1.0" encoding="UTF-8" ?>
+<!DOCTYPE manualpage SYSTEM "../style/manualpage.dtd">
+<?xml-stylesheet type="text/xsl" href="../style/manual.en.xsl"?>
+
+<manualpage>
+<relativepath href=".."/>
+
+<title>Debugging Memory Allocation in APR</title>
+
+<summary>
+ <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>
+</summary>
+
+<section id="options"><title>Available debugging options</title>
+ <section id="alloc_debug">
+ <title>Allocation Debugging - ALLOC_DEBUG</title>
+
+ <note>Debugging support: Define this to enable code which
+ helps detect re-use of <code>free()</code>d memory and other such
+ nonsense.</note>
+
+ <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>
+ </section>
+
+ <section id="alloc_use_malloc">
+ <title>Malloc Support - ALLOC_USE_MALLOC</title>
+
+ <note>If defined all allocations will be done with
+ <code>malloc()</code> and <code>free()</code>d appropriately at the
+ end.</note>
+
+ <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>
+ </section>
+
+ <section id="pool_debug"><title>Pool Debugging - POOL_DEBUG</title>
+ <note>This is intended to detect cases where the wrong pool is
+ used when assigning data to an object in another pool.</note>
+
+ <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>
+ </section>
+
+ <section id="make_table_profile">
+ <title>Table Debugging - MAKE_TABLE_PROFILE</title>
+
+ <note>Provide diagnostic information about make_table() calls
+ which are possibly too small.</note>
+
+ <p>This requires a recent gcc which supports
+ <code>__builtin_return_address()</code>. The error_log output will be a
+ message such as:</p>
+ <example>
+ table_push: apr_table_t created by 0x804d874 hit limit of 10
+ </example>
+
+ <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>
+ </section>
+
+ <section id="alloc_stats">
+ <title>Allocation Statistics - ALLOC_STATS</title>
+
+ <note>Provide some statistics on the cost of allocations.</note>
+
+ <p>This requires a bit of an understanding of how alloc.c works.</p>
+ </section>
+</section>
+
+<section id="combo"><title>Allowable Combinations</title>
+
+ <p>Not all the options outlined above can be activated at the
+ same time. the following table gives more information.</p>
+
+ <table border="1" style="zebra">
+ <tr><th></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><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><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>
+</section>
+
+<section id="howto"><title>Activating Debugging Options</title>
+
+ <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>
+
+ <example>
+ /*<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 />
+ <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 />
+ </indent>
+ #ifdef ALLOC_USE_MALLOC<br />
+ <indent>
+ void *allocation_list;<br />
+ </indent>
+ #endif<br />
+ #ifdef POOL_DEBUG<br />
+ <indent>
+ struct ap_pool_t *joined;<br />
+ </indent>
+ #endif<br />
+ <indent>
+ int (*apr_abort)(int retcode);<br />
+ struct datastruct *prog_data;<br />
+ </indent>
+ } ap_pool_t;
+ </example>
+
+ <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>
+
+ <note><title>Note</title>
+ <p>In order to use the various options the server <strong>must</strong>
+ be rebuilt after editing the header file.</p>
+ </note>
+</section>
+</manualpage>
+
projects / thirdparty / apache / httpd.git / commitdiff
