htdocs/manual/upgrading_to_1_3.html - httpd - Git at Google

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     <title>Upgrading to 1.3 from 1.2</title>
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     <h1 align="CENTER">Upgrading to 1.3 from 1.2</h1>

     <p>In order to assist folks upgrading we are now going to
     maintain a document describing information critical to existing
     Apache users. Note that it only lists differences between
     recent major releases, so for example, folks using Apache 1.1
     or earlier will have to figure out what changed up to Apache
     1.2 before this document can be considered relevant. Old users
     could look at the <code>src/CHANGES</code> file which tracks
     code changes.</p>

     <p>These are intended to be brief notes, and you should be able
     to find more information in either the <a
     href="new_features_1_3.html">New Features</a> document, or in
     the <code>src/CHANGES</code> file.</p>

     <h3>Compile-Time Configuration Changes</h3>

     <ul>
       <li>The source code has been <a
       href="sourcereorg.html">reorganized</a>, which affects anyone
       with custom modules or modifications. But also, the
       <code>Module</code> directive has been changed to the
       <code>AddModule</code> directive.</li>

       <li>The <code>Configuration</code> variable
       <code>EXTRA_LFLAGS</code> has been renamed
       <code>EXTRA_LDFLAGS</code>.</li>

       <li>The <code>-DMAXIMUM_DNS</code> definition has been
       obsoleted by changes to <code>mod_access</code> enforcing
       double-reverse DNS lookups when necessary.</li>

       <li>The <code>-DSERVER_SUBVERSION=\"string\"</code>
       compile-time option has been replaced with the run-time API
       call <code>ap_add_version_component()</code>. Compile-time
       modification of the server identity by the configuration
       scripts is no longer supported.</li>

       <li><code>mod_dir</code> has been split into two pieces
       <code><a
       href="mod/mod_autoindex.html">mod_autoindex</a></code>, and
       <code><a href="mod/mod_dir.html">mod_dir</a></code>.</li>

       <li><a
       href="mod/mod_browser.html"><code>mod_browser</code></a> has
       been replaced by <a
       href="mod/mod_setenvif.html"><code>mod_setenvif</code></a>.</li>

       <li>IRIX systems with untrusted users who can write CGIs
       which execute as the same uid as httpd should consider using
       <code>suexec</code>, or adding
       <code>-DUSE_FCNTL_SERIALIZED_ACCEPT</code> to
       <code>EXTRA_CFLAGS</code>. This is slower, more information
       is available on the <a
       href="misc/perf-tuning.html#serialize">performance tuning
       page</a>. There is a mild denial of service attack possible
       with the default config, but the default config is an order
       of magnitude faster.</li>

       <li><code>mod_auth_msql</code> has been removed from the
       distribution.</li>

       <li>The new Apache Autoconf-style Interface (APACI) was added
       to the top-level to provide a real out-of-the-box build and
       installation procedure for the complete Apache package.</li>
     </ul>

     <h3>Run-Time Configuration Changes</h3>

     <ul>
       <li>
         There have been numerous changes to the default config
         files. Ensure that you compare your existing configuration
         files with the new ones to ensure there aren't any
         undesired differences. In particular:

         <ul>
           <li>As of Apache 1.3.0, the current config files apply
           different <a href="mod/core.html#options">Options</a> and
           <a href="mod/core.html#allowoverride">AllowOverride</a>
           settings to various directories than were used in
           1.2.</li>

           <li>As of the release following Apache 1.3.3, the three
           config file templates have been merged into
           <samp>httpd.conf-dist</samp> and the order of the
           directives changed.</li>
         </ul>
       </li>

       <li>As of 1.3.2, <a
       href="mod/mod_expires.html"><code>mod_expires</code></a> will
       add Expires headers to content that does not come from a file
       on disk, unless you are using a modification time based
       setting. Previously, it would never add an Expires header
       unless content came from a file on disk. This could result in
       Expires headers being added in places where they were not
       previously added.</li>

       <li>Standalone <strong><samp>FancyIndexing</samp></strong>
       directives are now combined with the settings of any
       <samp>IndexOptions</samp> directive already in effect, rather
       than replacing them.</li>

       <li>
         <strong><samp>AuthName</samp> strings will need to be
         quoted</strong> in <samp>.htaccess</samp> or server
         configuration files if they contain blank characters (like
         spaces). For example, if you use an <samp>AuthName</samp>
         directive like this:
 <pre>
      AuthName This and That

 </pre>
         you will need to change it to
 <pre>
      AuthName "This and That"

 </pre>
         This change was made for consistency in the config
         language.
       </li>

       <li>
         <strong>As of Apache 1.3.1, methods listed in
         <samp>&lt;Limit&gt;</samp> directives must be
         uppercase.</strong> Method names, such as <samp>GET</samp>,
         <samp>POST</samp>, and <samp>PUT</samp> are defined as
         being case-sensitive. That is, a <samp>GET</samp> request
         is different from a <samp>get</samp> request. Prior to
         Apache 1.3.1, the <samp>&lt;Limit&gt;</samp> directive
         parser incorrectly treated both of these as being the same.
         Apache's built-in method limit processing currently only
         understands uppercase method names, so if you've used
         clauses such as
         "<samp>&lt;Limit&nbsp;Get&nbsp;post&gt;</samp>" in your
         configuration files, you need to correct them to use
         uppercase names.

         <p>Unrecognized method names in the server configuration
         files will result in the server logging an error message
         and failing to start. In <samp>.htaccess</samp> files,
         unknown methods will cause the server to log an error to
         its error log and return an 'Internal Server Error' page to
         the client.</p>
       </li>

       <li><strong>The default Apache ServerRoot directory
       changed</strong> from the NCSA-compatible
       <samp>/usr/local/etc/httpd/</samp> to
       <samp>/usr/local/apache/</samp>. This change covers only the
       default setting (and the documentation); it is of course
       possible to override it using the <em>-d ServerRoot</em> and
       <em>-f httpd.conf</em> switches when starting apache.</li>

       <li>Folks using HTTP/1.1-style virtual hosting will need to
       list the ip:port pairs that are supposed to have
       HTTP/1.1-style virtual hosting via the <a
       href="mod/core.html#namevirtualhost"><code>NameVirtualHost</code></a>
       directive (one directive per pair). Previously this support
       was given implicitly on the "main server address". Now it has
       to be explicitly listed so as to avoid many problems that
       users had. Please see the <a href="vhosts/">Apache Virtual
       Host documentation</a> for further details on
       configuration.</li>

       <li>The precedence of virtual hosts has been reversed
       (applies mainly to vhosts using HTTP/1.1 Host: headers, and
       the <a href="mod/core.html#serverpath">ServerPath</a>
       directive). Now the earlier vhosts in the file have
       precedence over the later vhosts.</li>

       <li><code>HostnameLookups</code> defaults to Off.</li>

       <li><strong><samp>REMOTE_HOST</samp> CGI variable
       changed.</strong> In Apache 1.2 and earlier, the
       <samp>REMOTE_HOST</samp> environment variable made available
       to CGI scripts was set to either the full DNS name of the
       client, or else to the client's IP address if the name was
       not known. This behavior differed from that specified by the
       CGI specification, which defines this variable as being NULL
       if the name isn't known. In Apache 1.3, we have made this
       correction. <samp>REMOTE_ADDR</samp> always contains the
       client's IP address, but <samp>REMOTE_HOST</samp> is only
       defined when the server has been able to determine the
       client's DNS name.</li>

       <li>The undocumented <a
       href="mod/mod_access.html"><code>mod_access</code></a> syntax
       "allow user-agents" was removed. The replacement is the more
       general "allow from env".</li>

       <li>When using wildcards in pathnames (such as * and ?) they
       no longer match / (slash). That is, they more closely behave
       how a UNIX shell behaves. This affects
       <code>&lt;Directory&gt;</code> directives, for example.</li>

       <li>If no <code>TransferLog</code> directive is given then
       nothing will be logged. (Previously it would default to
       <code>logs/access_log</code>.)</li>

       <li>Apache now has <a
       href="mod/core.html#loglevel">configurable error logging
       levels</a>, and the default eliminates some messages that
       earlier versions always generated.</li>

       <li>When booting, Apache will now detach itself from stdin,
       stdout, and stderr. stderr will not be detached until after
       the config files have been read so you will be able to see
       initial error messages. After that all errors are logged in
       the error_log. This makes it more convenient to start Apache
       via rsh, ssh, or crontabs.</li>

       <li>&lt;Files&gt; sections previously could take a full
       pathname, and were matched against the full pathnames. This
       had some inconsistencies, and was removed. To emulate this
       older behavior use a &lt;Files&gt; section nested inside a
       &lt;Directory&gt; section.</li>

       <li>&lt;Location&gt; matching behavior with respect to
       slashes has changed. See the <a
       href="mod/core.html#location">&lt;Location&gt;
       documentation</a> for more info.</li>
     </ul>

     <h3>Misc Changes</h3>

     <ul>
       <li><code>ServerType inetd</code> has been deprecated. It
       still exists, but bugs are unlikely to be fixed.</li>

       <li><code>httpd_monitor</code> has been deprecated. The
       replacement is to use <code>mod_status</code> and make a
       request to a URL such as
       <code>http://myhost/server-status?refresh=10</code>.</li>

       <li>
         Apache now provides an effectively unbuffered connection
         for CGI scripts. This means that data will be sent to the
         client as soon as the CGI pauses or stops output;
         previously, Apache would buffer the output up to a fixed
         buffer size before sending, which could result in the user
         viewing an empty page until the CGI finished or output a
         complete buffer. It is no longer necessary to use an "nph-"
         CGI to get unbuffered output. Given that most CGIs are
         written in a language that by default does buffering
         (<em>e.g.</em>, perl) this shouldn't have a detrimental
         effect on performance.

         <p>"nph-" CGIs, which formerly provided a direct socket to
         the client without any server post-processing, were not
         fully compatible with HTTP/1.1 or SSL support. As such they
         would have had to implement the transport details, such as
         encryption or chunking, in order to work properly in
         certain situations. Now, the only difference between nph
         and non-nph scripts is "non-parsed headers".</p>
       </li>

       <li><code>dbmmanage</code> has been overhauled.</li>
     </ul>

     <h3>Third Party Modules</h3>

     <p>The following changes between the 1.2 and 1.3 API may
     require slight changes in third party modules not maintained by
     Apache.</p>

     <ul>
       <li>To avoid symbol clashes with third-party code compiled
       into the server, the general prefix `<code>ap_</code>' was
       globally applied to the following classes of symbols: Apache
       provided general functions (<em>e.g.</em>,
       <code>ap_cpystrn</code>), public API functions
       (<em>e.g.</em>, <code>palloc</code>, <code>bgets</code>) and
       private functions which can't be made static (because of
       cross-object usage) but should be (<em>e.g.</em>,
       <code>new_connection</code>). For backward source
       compatibility with Apache 1.2 a new header file named
       <code>compat.h</code> was created which provides defines for
       the old symbol names. You'll either have to <code>#include
       compat.h</code> or update the API symbols you use.</li>

       <li>Be sure and examine the <a href="sourcereorg.html">source
       code reorganization page</a> to see whether any item there
       affects you.</li>

       <li>Use of <samp>SERVER_VERSION</samp> definition. If
       third-party modules reference the server version string using
       this symbol, they should be corrected to obtain it by calling
       the new API routine
       <code>const&nbsp;char&nbsp;*ap_get_server_version()</code>.</li>

       <li><code>ap_construct_url</code> prototype change. The
       second parameter was previously a <code>server_rec</code>, it
       has been changed to a <code>request_rec</code>.</li>

       <li>
         The <code>table</code> datatype has been made an opaque
         type. Code which assumes a <code>table</code> is the same
         as an <code>array_header</code> will not compile. This is
         actually a change to enforce the API the way it was
         intended, all versions of Apache have had a
         <code>table_elts()</code> function which is intended for
         code which needs to access the elements of a table. The
         changes required for this are pretty easy, and work with
         all versions of Apache.

         <p>Suppose <code>t</code> is a table. Whenever code refers
         to <code>t-&gt;elts</code>, replace it with something like
         this:</p>

         <blockquote>
 <pre>
     array_header *arr = table_elts(t);
     table_entry *elts = (table_entry *)arr-&gt;elts;
 </pre>
         </blockquote>
         Whenever code refers to <code>t-&gt;nelts</code> use
         <code>arr-&gt;nelts</code>. Many examples can be found in
         the standard modules, search for <code>table_elts</code>.
       </li>
     </ul>
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	<html xmlns="http://www.w3.org/1999/xhtml">
	<head>
	<meta name="generator" content="HTML Tidy, see www.w3.org" />

	<title>Upgrading to 1.3 from 1.2</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">Upgrading to 1.3 from 1.2</h1>

	<p>In order to assist folks upgrading we are now going to
	maintain a document describing information critical to existing
	Apache users. Note that it only lists differences between
	recent major releases, so for example, folks using Apache 1.1
	or earlier will have to figure out what changed up to Apache
	1.2 before this document can be considered relevant. Old users
	could look at the <code>src/CHANGES</code> file which tracks
	code changes.</p>

	<p>These are intended to be brief notes, and you should be able
	to find more information in either the <a
	href="new_features_1_3.html">New Features</a> document, or in
	the <code>src/CHANGES</code> file.</p>

	<h3>Compile-Time Configuration Changes</h3>

	<ul>
	<li>The source code has been <a
	href="sourcereorg.html">reorganized</a>, which affects anyone
	with custom modules or modifications. But also, the
	<code>Module</code> directive has been changed to the
	<code>AddModule</code> directive.</li>

	<li>The <code>Configuration</code> variable
	<code>EXTRA_LFLAGS</code> has been renamed
	<code>EXTRA_LDFLAGS</code>.</li>

	<li>The <code>-DMAXIMUM_DNS</code> definition has been
	obsoleted by changes to <code>mod_access</code> enforcing
	double-reverse DNS lookups when necessary.</li>

	<li>The <code>-DSERVER_SUBVERSION=\"string\"</code>
	compile-time option has been replaced with the run-time API
	call <code>ap_add_version_component()</code>. Compile-time
	modification of the server identity by the configuration
	scripts is no longer supported.</li>

	<li><code>mod_dir</code> has been split into two pieces
	<code><a
	href="mod/mod_autoindex.html">mod_autoindex</a></code>, and
	<code><a href="mod/mod_dir.html">mod_dir</a></code>.</li>

	<li><a
	href="mod/mod_browser.html"><code>mod_browser</code></a> has
	been replaced by <a
	href="mod/mod_setenvif.html"><code>mod_setenvif</code></a>.</li>

	<li>IRIX systems with untrusted users who can write CGIs
	which execute as the same uid as httpd should consider using
	<code>suexec</code>, or adding
	<code>-DUSE_FCNTL_SERIALIZED_ACCEPT</code> to
	<code>EXTRA_CFLAGS</code>. This is slower, more information
	is available on the <a
	href="misc/perf-tuning.html#serialize">performance tuning
	page</a>. There is a mild denial of service attack possible
	with the default config, but the default config is an order
	of magnitude faster.</li>

	<li><code>mod_auth_msql</code> has been removed from the
	distribution.</li>

	<li>The new Apache Autoconf-style Interface (APACI) was added
	to the top-level to provide a real out-of-the-box build and
	installation procedure for the complete Apache package.</li>
	</ul>

	<h3>Run-Time Configuration Changes</h3>

	<ul>
	<li>
	There have been numerous changes to the default config
	files. Ensure that you compare your existing configuration
	files with the new ones to ensure there aren't any
	undesired differences. In particular:

	<ul>
	<li>As of Apache 1.3.0, the current config files apply
	different <a href="mod/core.html#options">Options</a> and
	<a href="mod/core.html#allowoverride">AllowOverride</a>
	settings to various directories than were used in
	1.2.</li>

	<li>As of the release following Apache 1.3.3, the three
	config file templates have been merged into
	<samp>httpd.conf-dist</samp> and the order of the
	directives changed.</li>
	</ul>
	</li>

	<li>As of 1.3.2, <a
	href="mod/mod_expires.html"><code>mod_expires</code></a> will
	add Expires headers to content that does not come from a file
	on disk, unless you are using a modification time based
	setting. Previously, it would never add an Expires header
	unless content came from a file on disk. This could result in
	Expires headers being added in places where they were not
	previously added.</li>

	<li>Standalone <strong><samp>FancyIndexing</samp></strong>
	directives are now combined with the settings of any
	<samp>IndexOptions</samp> directive already in effect, rather
	than replacing them.</li>

	<li>
	<strong><samp>AuthName</samp> strings will need to be
	quoted</strong> in <samp>.htaccess</samp> or server
	configuration files if they contain blank characters (like
	spaces). For example, if you use an <samp>AuthName</samp>
	directive like this:
	<pre>
	AuthName This and That

	</pre>
	you will need to change it to
	<pre>
	AuthName "This and That"

	</pre>
	This change was made for consistency in the config
	language.
	</li>

	<li>
	<strong>As of Apache 1.3.1, methods listed in
	<samp><Limit></samp> directives must be
	uppercase.</strong> Method names, such as <samp>GET</samp>,
	<samp>POST</samp>, and <samp>PUT</samp> are defined as
	being case-sensitive. That is, a <samp>GET</samp> request
	is different from a <samp>get</samp> request. Prior to
	Apache 1.3.1, the <samp><Limit></samp> directive
	parser incorrectly treated both of these as being the same.
	Apache's built-in method limit processing currently only
	understands uppercase method names, so if you've used
	clauses such as
	"<samp><Limit Get post></samp>" in your
	configuration files, you need to correct them to use
	uppercase names.

	<p>Unrecognized method names in the server configuration
	files will result in the server logging an error message
	and failing to start. In <samp>.htaccess</samp> files,
	unknown methods will cause the server to log an error to
	its error log and return an 'Internal Server Error' page to
	the client.</p>
	</li>

	<li><strong>The default Apache ServerRoot directory
	changed</strong> from the NCSA-compatible
	<samp>/usr/local/etc/httpd/</samp> to
	<samp>/usr/local/apache/</samp>. This change covers only the
	default setting (and the documentation); it is of course
	possible to override it using the <em>-d ServerRoot</em> and
	<em>-f httpd.conf</em> switches when starting apache.</li>

	<li>Folks using HTTP/1.1-style virtual hosting will need to
	list the ip:port pairs that are supposed to have
	HTTP/1.1-style virtual hosting via the <a
	href="mod/core.html#namevirtualhost"><code>NameVirtualHost</code></a>
	directive (one directive per pair). Previously this support
	was given implicitly on the "main server address". Now it has
	to be explicitly listed so as to avoid many problems that
	users had. Please see the <a href="vhosts/">Apache Virtual
	Host documentation</a> for further details on
	configuration.</li>

	<li>The precedence of virtual hosts has been reversed
	(applies mainly to vhosts using HTTP/1.1 Host: headers, and
	the <a href="mod/core.html#serverpath">ServerPath</a>
	directive). Now the earlier vhosts in the file have
	precedence over the later vhosts.</li>

	<li><code>HostnameLookups</code> defaults to Off.</li>

	<li><strong><samp>REMOTE_HOST</samp> CGI variable
	changed.</strong> In Apache 1.2 and earlier, the
	<samp>REMOTE_HOST</samp> environment variable made available
	to CGI scripts was set to either the full DNS name of the
	client, or else to the client's IP address if the name was
	not known. This behavior differed from that specified by the
	CGI specification, which defines this variable as being NULL
	if the name isn't known. In Apache 1.3, we have made this
	correction. <samp>REMOTE_ADDR</samp> always contains the
	client's IP address, but <samp>REMOTE_HOST</samp> is only
	defined when the server has been able to determine the
	client's DNS name.</li>

	<li>The undocumented <a
	href="mod/mod_access.html"><code>mod_access</code></a> syntax
	"allow user-agents" was removed. The replacement is the more
	general "allow from env".</li>

	<li>When using wildcards in pathnames (such as * and ?) they
	no longer match / (slash). That is, they more closely behave
	how a UNIX shell behaves. This affects
	<code><Directory></code> directives, for example.</li>

	<li>If no <code>TransferLog</code> directive is given then
	nothing will be logged. (Previously it would default to
	<code>logs/access_log</code>.)</li>

	<li>Apache now has <a
	href="mod/core.html#loglevel">configurable error logging
	levels</a>, and the default eliminates some messages that
	earlier versions always generated.</li>

	<li>When booting, Apache will now detach itself from stdin,
	stdout, and stderr. stderr will not be detached until after
	the config files have been read so you will be able to see
	initial error messages. After that all errors are logged in
	the error_log. This makes it more convenient to start Apache
	via rsh, ssh, or crontabs.</li>

	<li><Files> sections previously could take a full
	pathname, and were matched against the full pathnames. This
	had some inconsistencies, and was removed. To emulate this
	older behavior use a <Files> section nested inside a
	<Directory> section.</li>

	<li><Location> matching behavior with respect to
	slashes has changed. See the <a
	href="mod/core.html#location"><Location>
	documentation</a> for more info.</li>
	</ul>

	<h3>Misc Changes</h3>

	<ul>
	<li><code>ServerType inetd</code> has been deprecated. It
	still exists, but bugs are unlikely to be fixed.</li>

	<li><code>httpd_monitor</code> has been deprecated. The
	replacement is to use <code>mod_status</code> and make a
	request to a URL such as
	<code>http://myhost/server-status?refresh=10</code>.</li>

	<li>
	Apache now provides an effectively unbuffered connection
	for CGI scripts. This means that data will be sent to the
	client as soon as the CGI pauses or stops output;
	previously, Apache would buffer the output up to a fixed
	buffer size before sending, which could result in the user
	viewing an empty page until the CGI finished or output a
	complete buffer. It is no longer necessary to use an "nph-"
	CGI to get unbuffered output. Given that most CGIs are
	written in a language that by default does buffering
	(<em>e.g.</em>, perl) this shouldn't have a detrimental
	effect on performance.

	<p>"nph-" CGIs, which formerly provided a direct socket to
	the client without any server post-processing, were not
	fully compatible with HTTP/1.1 or SSL support. As such they
	would have had to implement the transport details, such as
	encryption or chunking, in order to work properly in
	certain situations. Now, the only difference between nph
	and non-nph scripts is "non-parsed headers".</p>
	</li>

	<li><code>dbmmanage</code> has been overhauled.</li>
	</ul>

	<h3>Third Party Modules</h3>

	<p>The following changes between the 1.2 and 1.3 API may
	require slight changes in third party modules not maintained by
	Apache.</p>

	<ul>
	<li>To avoid symbol clashes with third-party code compiled
	into the server, the general prefix `<code>ap_</code>' was
	globally applied to the following classes of symbols: Apache
	provided general functions (<em>e.g.</em>,
	<code>ap_cpystrn</code>), public API functions
	(<em>e.g.</em>, <code>palloc</code>, <code>bgets</code>) and
	private functions which can't be made static (because of
	cross-object usage) but should be (<em>e.g.</em>,
	<code>new_connection</code>). For backward source
	compatibility with Apache 1.2 a new header file named
	<code>compat.h</code> was created which provides defines for
	the old symbol names. You'll either have to <code>#include
	compat.h</code> or update the API symbols you use.</li>

	<li>Be sure and examine the <a href="sourcereorg.html">source
	code reorganization page</a> to see whether any item there
	affects you.</li>

	<li>Use of <samp>SERVER_VERSION</samp> definition. If
	third-party modules reference the server version string using
	this symbol, they should be corrected to obtain it by calling
	the new API routine
	<code>const char *ap_get_server_version()</code>.</li>

	<li><code>ap_construct_url</code> prototype change. The
	second parameter was previously a <code>server_rec</code>, it
	has been changed to a <code>request_rec</code>.</li>

	<li>
	The <code>table</code> datatype has been made an opaque
	type. Code which assumes a <code>table</code> is the same
	as an <code>array_header</code> will not compile. This is
	actually a change to enforce the API the way it was
	intended, all versions of Apache have had a
	<code>table_elts()</code> function which is intended for
	code which needs to access the elements of a table. The
	changes required for this are pretty easy, and work with
	all versions of Apache.

	<p>Suppose <code>t</code> is a table. Whenever code refers
	to <code>t->elts</code>, replace it with something like
	this:</p>

	<blockquote>
	<pre>
	array_header *arr = table_elts(t);
	table_entry elts = (table_entry )arr->elts;
	</pre>
	</blockquote>
	Whenever code refers to <code>t->nelts</code> use
	<code>arr->nelts</code>. Many examples can be found in
	the standard modules, search for <code>table_elts</code>.
	</li>
	</ul>
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