diff options
| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 06:33:50 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 06:33:50 +0000 |
| commit | fe39ffb8b90ae4e002ed73fe98617cd590abb467 (patch) | |
| tree | b80e5956907d8aeaaffe4e4f0c068c0e6157ce8b /docs/manual/platform/ebcdic.html.en | |
| parent | Initial commit. (diff) | |
| download | apache2-fe39ffb8b90ae4e002ed73fe98617cd590abb467.tar.xz apache2-fe39ffb8b90ae4e002ed73fe98617cd590abb467.zip | |
Adding upstream version 2.4.56.upstream/2.4.56
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'docs/manual/platform/ebcdic.html.en')
| -rw-r--r-- | docs/manual/platform/ebcdic.html.en | 616 |
1 files changed, 616 insertions, 0 deletions
diff --git a/docs/manual/platform/ebcdic.html.en b/docs/manual/platform/ebcdic.html.en new file mode 100644 index 0000000..01b95c8 --- /dev/null +++ b/docs/manual/platform/ebcdic.html.en @@ -0,0 +1,616 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!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> +<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" /> +<!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>The Apache EBCDIC Port - Apache HTTP Server Version 2.4</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 rel="stylesheet" type="text/css" href="../style/css/prettify.css" /> +<script src="../style/scripts/prettify.min.js" type="text/javascript"> +</script> + +<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="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p> +<p class="apache">Apache HTTP Server Version 2.4</p> +<img alt="" src="../images/feather.png" /></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 2.4</a> > <a href="./">Platform Specific Notes</a></div><div id="page-content"><div id="preamble"><h1>The Apache EBCDIC Port</h1> +<div class="toplang"> +<p><span>Available Languages: </span><a href="../en/platform/ebcdic.html" title="English"> en </a> | +<a href="../ko/platform/ebcdic.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p> +</div> + + + <div class="warning"><strong>Warning:</strong> This document + has not been updated to take into account changes made in + the 2.0 version of the Apache HTTP Server. Some of the + information may still be relevant, but please use it with care. + </div> + + </div> +<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#overview">Overview of the Apache EBCDIC Port</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#design">Design Goals</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#technical">Technical Solution</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#porting">Porting Notes</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#document">Document Storage Notes</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#modules">Apache Modules' Status</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#third-party">Third Party Modules' Status</a></li> +</ul><h3>See also</h3><ul class="seealso"><li><a href="#comments_section">Comments</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="overview" id="overview">Overview of the Apache EBCDIC Port</a></h2> + + + + <p>Version 1.3 of the Apache HTTP Server was the first version + which included a port to a (non-ASCII) mainframe machine which + uses the EBCDIC character set as its native codeset.</p> + + <p>(It is the SIEMENS family of mainframes running the <a href="http://www.siemens.de/servers/bs2osd/osdbc_us.htm">BS2000/OSD + operating system</a>. This mainframe OS nowadays features a + SVR4-derived POSIX subsystem).</p> + + <p>The port was started initially to</p> + + <ul> + <li>prove the feasibility of porting <a href="http://httpd.apache.org/">the Apache HTTP server</a> to + this platform</li> + + <li>find a "worthy and capable" successor for the venerable + <a href="http://www.w3.org/Daemon/">CERN-3.0</a> daemon + (which was ported a couple of years ago), and to</li> + + <li>prove that Apache's preforking process model can on this + platform easily outperform the accept-fork-serve model used + by CERN by a factor of 5 or more.</li> + </ul> + + <p>This document serves as a rationale to describe some of the + design decisions of the port to this machine.</p> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="design" id="design">Design Goals</a></h2> + + + + <p>One objective of the EBCDIC port was to maintain enough + backwards compatibility with the (EBCDIC) CERN server to make + the transition to the new server attractive and easy. This + required the addition of a configurable method to define + whether a HTML document was stored in ASCII (the only format + accepted by the old server) or in EBCDIC (the native document + format in the POSIX subsystem, and therefore the only realistic + format in which the other POSIX tools like <code>grep</code> or + <code>sed</code> could operate on the documents). The current + solution to this is a "pseudo-MIME-format" which is intercepted + and interpreted by the Apache server (see below). Future versions + might solve the problem by defining an "ebcdic-handler" for all + documents which must be converted.</p> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="technical" id="technical">Technical Solution</a></h2> + + + + <p>Since all Apache input and output is based upon the BUFF + data type and its methods, the easiest solution was to add the + conversion to the BUFF handling routines. The conversion must + be settable at any time, so a BUFF flag was added which defines + whether a BUFF object has currently enabled conversion or not. + This flag is modified at several points in the HTTP + protocol:</p> + + <ul> + <li><strong>set</strong> before a request is received + (because the request and the request header lines are always + in ASCII format)</li> + + <li><strong>set/unset</strong> when the request body is + received - depending on the content type of the request body + (because the request body may contain ASCII text or a binary + file)</li> + + <li><strong>set</strong> before a reply header is sent + (because the response header lines are always in ASCII + format)</li> + + <li><strong>set/unset</strong> when the response body is sent + - depending on the content type of the response body (because + the response body may contain text or a binary file)</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="porting" id="porting">Porting Notes</a></h2> + + + + <ol> + <li> + <p>The relevant changes in the source are <code>#ifdef</code>'ed + into two categories:</p> + + <dl> + <dt><code><strong>#ifdef + CHARSET_EBCDIC</strong></code></dt> + + <dd> + <p>Code which is needed for any EBCDIC based machine. + This includes character translations, differences in + contiguity of the two character sets, flags which + indicate which part of the HTTP protocol has to be + converted and which part doesn't <em>etc.</em></p> + </dd> + + <dt><code><strong>#ifdef _OSD_POSIX</strong></code></dt> + + <dd> + <p>Code which is needed for the SIEMENS BS2000/OSD + mainframe platform only. This deals with include file + differences and socket implementation topics which are + only required on the BS2000/OSD platform.</p> + </dd> + </dl> + </li> + + <li> + <p>The possibility to translate between ASCII and EBCDIC at + the socket level (on BS2000 POSIX, there is a socket option + which supports this) was intentionally <em>not</em> chosen, + because the byte stream at the HTTP protocol level consists + of a mixture of protocol related strings and non-protocol + related raw file data. HTTP protocol strings are always + encoded in ASCII (the <code>GET</code> request, any Header: lines, + the chunking information <em>etc.</em>) whereas the file transfer + parts (<em>i.e.</em>, GIF images, CGI output <em>etc.</em>) + should usually be just "passed through" by the server. This + separation between "protocol string" and "raw data" is + reflected in the server code by functions like <code>bgets()</code> + or <code>rvputs()</code> for strings, and functions like + <code>bwrite()</code> for binary data. A global translation + of everything would therefore be inadequate.</p> + + <p>(In the case of text files of course, provisions must be + made so that EBCDIC documents are always served in + ASCII)</p> + </li> + + <li> + <p>This port therefore features a built-in protocol level + conversion for the server-internal strings (which the + compiler translated to EBCDIC strings) and thus for all + server-generated documents. The hard coded ASCII escapes + <code>\012</code> and <code>\015</code> which are ubiquitous + in the server code are an exception: they are already the binary + encoding of the ASCII <code>\n</code> and <code>\r</code> and + must not be converted to ASCII a second time. + This exception is only relevant for server-generated strings; + and <em>external</em> EBCDIC documents are not expected to + contain ASCII newline characters.</p> + </li> + + <li> + <p>By examining the call hierarchy for the BUFF management + routines, I added an "ebcdic/ascii conversion layer" which + would be crossed on every puts/write/get/gets, and a + conversion flag which allowed enabling/disabling the + conversions on-the-fly. Usually, a document crosses this + layer twice from its origin source (a file or CGI output) to + its destination (the requesting client): <code>file -> + Apache</code>, and <code>Apache -> client</code>.</p> + + <p>The server can now read the header lines of a CGI-script + output in EBCDIC format, and then find out that the remainder + of the script's output is in ASCII (like in the case of the + output of a WWW Counter program: the document body contains a + GIF image). All header processing is done in the native + EBCDIC format; the server then determines, based on the type + of document being served, whether the document body (except + for the chunking information, of course) is in ASCII already + or must be converted from EBCDIC.</p> + </li> + + <li> + <p>For Text documents (MIME types text/plain, text/html + <em>etc.</em>), an implicit translation to ASCII can be + used, or (if the users prefer to store some documents in + raw ASCII form for faster serving, or because the files + reside on a NFS-mounted directory tree) can be served + without conversion.</p> + + <p><strong>Example:</strong></p> + + <p>to serve files with the suffix <code>.ahtml</code> as a + raw ASCII <code>text/html</code> document without implicit + conversion (and suffix <code>.ascii</code> as ASCII + <code>text/plain</code>), use the directives:</p> + + <div class="example"><p><code> + AddType text/x-ascii-html .ahtml <br /> + AddType text/x-ascii-plain .ascii + </code></p></div> + + <p>Similarly, any <code>text/foo</code> MIME type can be + served as "raw ASCII" by configuring a MIME type + "<code>text/x-ascii-foo</code>" for it using + <code>AddType</code>.</p> + </li> + + <li> + <p>Non-text documents are always served "binary" without + conversion. This seems to be the most sensible choice for, + .<em>e.g.</em>, GIF/ZIP/AU file types. This of course + requires the user to copy them to the mainframe host using + the "<code>rcp -b</code>" binary switch.</p> + </li> + + <li> + <p>Server parsed files are always assumed to be in native + (<em>i.e.</em>, EBCDIC) format as used on the machine, and + are converted after processing.</p> + </li> + + <li> + <p>For CGI output, the CGI script determines whether a + conversion is needed or not: by setting the appropriate + Content-Type, text files can be converted, or GIF output can + be passed through unmodified. An example for the latter case + is the wwwcount program which we ported as well.</p> + </li> + + </ol> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="document" id="document">Document Storage Notes</a></h2> + + + + <h3><a name="binary" id="binary">Binary Files</a></h3> + + + + <p>All files with a <code>Content-Type:</code> which does not + start with <code>text/</code> are regarded as <em>binary + files</em> by the server and are not subject to any conversion. + Examples for binary files are GIF images, gzip-compressed files + and the like.</p> + + <p>When exchanging binary files between the mainframe host and + a Unix machine or Windows PC, be sure to use the ftp "binary" + (<code>TYPE I</code>) command, or use the + <code>rcp -b</code> command from the mainframe host (the + <code>-b</code> switch is not supported in unix + <code>rcp</code>'s).</p> + + + + <h3><a name="text" id="text">Text Documents</a></h3> + + + + <p>The default assumption of the server is that Text Files + (<em>i.e.</em>, all files whose <code>Content-Type:</code> + starts with <code>text/</code>) are stored in the native + character set of the host, EBCDIC.</p> + + + + <h3><a name="ssi" id="ssi">Server Side Included Documents</a></h3> + + + + <p>SSI documents must currently be stored in EBCDIC only. + No provision is made to convert it from ASCII before + processing.</p> + + + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="modules" id="modules">Apache Modules' Status</a></h2> + + + + <table class="bordered"> + <tr> + <th>Module</th> + <th>Status</th> + <th>Notes</th> + </tr> + + <tr> + <td><code class="module"><a href="../mod/core.html">core</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module">mod_access</code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_actions.html">mod_actions</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_alias.html">mod_alias</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_asis.html">mod_asis</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module">mod_auth</code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_authn_anon.html">mod_authn_anon</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_authn_dbm.html">mod_authn_dbm</a></code></td> + <td class="centered">?</td> + <td>with own <code>libdb.a</code></td> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_authz_dbm.html">mod_authz_dbm</a></code></td> + <td class="centered">?</td> + <td>with own <code>libdb.a</code></td> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_cern_meta.html">mod_cern_meta</a></code></td> + <td class="centered">?</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code>mod_digest</code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_so.html">mod_so</a></code></td> + <td class="centered">-</td> + <td>no shared libs</td> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_env.html">mod_env</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_example.html">mod_example</a></code></td> + <td class="centered">-</td> + <td>(test bed only)</td> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_expires.html">mod_expires</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_headers.html">mod_headers</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_imagemap.html">mod_imagemap</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_include.html">mod_include</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_info.html">mod_info</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code>mod_log_agent</code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code>mod_log_config</code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module">mod_log_referer</code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_mime_magic.html">mod_mime_magic</a></code></td> + <td class="centered">?</td> + <td>not ported yet</td> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td> + <td class="centered">+</td> + <td>untested</td> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_setenvif.html">mod_setenvif</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_speling.html">mod_speling</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_status.html">mod_status</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_userdir.html">mod_userdir</a></code></td> + <td class="centered">+</td> + <td /> + </tr> + + <tr> + <td><code class="module"><a href="../mod/mod_usertrack.html">mod_usertrack</a></code></td> + <td class="centered">?</td> + <td>untested</td> + </tr> + </table> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="third-party" id="third-party">Third Party Modules' Status</a></h2> + + + + <table class="bordered"> + <tr> + <th>Module</th> + <th>Status</th> + <th>Notes</th> + </tr> + + <tr> + <td><code><a href="https://tomcat.apache.org/connectors-doc-archive/jk2/">JK</a> (Formerly mod_jserv) + </code></td> + <td class="centered">-</td> + <td>JAVA still being ported.</td> + </tr> + + <tr> + <td><code><a href="http://www.php.net/">mod_php3</a></code></td> + <td class="centered">+</td> + <td><code>mod_php3</code> runs fine, with LDAP and GD + and FreeType libraries.</td> + </tr> + + <tr> + <td><code><a href="http://hpwww.ec-lyon.fr/~vincent/apache/mod_put.html">mod_put</a></code></td> + <td class="centered">?</td> + <td>untested</td> + </tr> + + <tr> + <td><code><a href="ftp://hachiman.vidya.com/pub/apache/">mod_session</a></code></td> + <td class="centered">-</td> + <td>untested</td> + </tr> + </table> + + </div></div> +<div class="bottomlang"> +<p><span>Available Languages: </span><a href="../en/platform/ebcdic.html" title="English"> en </a> | +<a href="../ko/platform/ebcdic.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p> +</div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Libera.chat, or sent to our <a href="https://httpd.apache.org/lists.html">mailing lists</a>.</div> +<script type="text/javascript"><!--//--><![CDATA[//><!-- +var comments_shortname = 'httpd'; +var comments_identifier = 'http://httpd.apache.org/docs/2.4/platform/ebcdic.html'; +(function(w, d) { + if (w.location.hostname.toLowerCase() == "httpd.apache.org") { + d.write('<div id="comments_thread"><\/div>'); + var s = d.createElement('script'); + s.type = 'text/javascript'; + s.async = true; + s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier; + (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s); + } + else { + d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>'); + } +})(window, document); +//--><!]]></script></div><div id="footer"> +<p class="apache">Copyright 2023 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="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><![CDATA[//><!-- +if (typeof(prettyPrint) !== 'undefined') { + prettyPrint(); +} +//--><!]]></script> +</body></html>
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