creating_ipkg_packages.htm

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<p><b><font size="5">IPK Creation Kit</font><br>
</b>(c)2006 Jeremy Collake &lt;<a href="mailto:jeremy.collake@gmail.com">jeremy.collake@gmail.com</a>&gt;<br>
<br>
<font color="#FF0000">!!! <b>ALPHA STAGE OF DEVELOPMENT. MAY NOT WORK AND HAVE 
MANY PROBLEMS</b> !!!</font></p>
<p>This document attempts to outline the process of creation of IPKG format 
packages with the IPK Creation Kit, giving specific emphasis on usage for 
embedded linux platforms such as <a href="http://www.openwrt.org">OpenWrt</a> 
and <a href="http://www.dd-wrt.com">DD-WRT</a>. It is a quick draft intended to 
encourage people to develop IPKs specific to certain firmwares for use with the
<a href="http://www.bitsum.com/firmware_mod_kit.htm">Firmware Modification Kit</a>, 
a kit that allows easy modification of firmware images without recompiling the 
sources.</p>
<p><b><font size="4">The structure of an IPK</font></b></p>
<p>IPK files are <b><i>archives</i></b> containing the following:</p>
<ul>
	<li><u><b>data.tar.gz</b></u> :&nbsp; contains data.tar:<ul>
		<li><u><b>data.tar</b></u> : These are the files that will be installed 
		to, or removed from, the file system. They are in their correct 
		locations in the directory tree starting at the root of the firmware 
		file system. For example:<ul>
			<li><font face="Courier"><b>./</b>usr/sbin/package<br>
			./tmp/package_config<br>
			./etc/package_config <i>-&gt; symbolic link</i> -&gt; ../tmp/config_folder<br>
			./tmp/package_config/package.conf<br>
			NOTE: </font><i>the &quot;.&quot; directory must be included in the path names</i></li>
		</ul>
		</li>
	</ul>
	</li>
	<li><b><u>control.tar.gz</u> </b>: contains control.tar:<ul>
		<li><u><b>control.tar</b></u> : These are files which give information 
		about the package. For examples, it's name, version, and dependencies.<ul>
			<li>./control : describes the package</li>
			<li>./conffiles : indicates which files in the package are used for 
			config files once installed</li>
		</ul>
		</li>
	</ul>
	</li>
	<li><b><u>debian_binary</u> </b>: the reason this exists is unknown. It's 
	perhaps some platform or format indicator. It is a text file that consists 
	of &quot;2.0&quot;. </li>
</ul>
<p>&nbsp;</p>
<p><b><font size="4">Using the IPK template</font></b></p>
<p>The IPK template directory contained in the Firmware Modification Kit makes 
it particularly easy to create IPK files without having to manually create them 
each time.</p>
<p><b><font size="4">Creating your own IPK</font></b></p>
<blockquote>
	<p><b><font size="4">Step 1</font></b></p>
	<p>Copy or extract the IPK template directory to a new directory named after 
	the package you are creating an IPK for. If you are copying, use &quot;cp -r&quot; to 
	copy the entire directory and all its contents.</p>
	<p><b><font size="4">Step 2</font></b></p>
	<p>In the new directory edit the &quot;<i>control</i>&quot; and &quot;<i>conffiles</i>&quot; 
	text files appropriately. The fields in &quot;control&quot; are probably 
	self-explanatory:</p>
	<p><i><b>control:</b></i></p>
	<table border="0" width="100%" bgcolor="#FFFFCC" id="table5">
		<tr>
			<td><br>
			<font face="Courier">Package: somepackage<br>
			Priority: optional<br>
			Depends: libpcap libncurses<br>
			Section: net<br>
			Description: A minimal and secure package of great sorts.<br>
			Maintainer: Junior Jim-Bob &lt;juniorjim.bob.com&gt;<br>
			Source: N/A<br>
			Version: 2.61-1<br>
			Architecture: mipsel<br>
&nbsp;</font></td>
		</tr>
	</table>
	<p>If you want to get fancy, the<i> Source</i> field can indicate a URL to 
	download the data.tar.gz portion of the package. If instead the package 
	files are included inside the PKG, leave &quot;N/A&quot; in this field.</p>
	<p>&quot;conffiles&quot; contains a listing of files in the package that are used for 
	configuration storage. This is helpful to preserve the configuration of the 
	package if it is updated, or if the configuration otherwise needs 
	preserving. It might look something like this after editing:</p>
	<p><i><b>conffiles:</b></i></p>
	<table border="0" width="100%" bgcolor="#FFFFCC" id="table6">
		<tr>
			<td><br>
			<font face="Courier">/etc/package_config/package.conf<br>
			/etc/package_config/moreconfig.conf<br>
&nbsp;</font></td>
		</tr>
	</table>
	<p><b><font size="4">Step 3</font></b></p>
	<p>Copy the package files into the folder in the same relative directories 
	to which they will be installed to the file system. Symbolic links are 
	allowed. For example:</p>
	<table border="0" width="100%" bgcolor="#FFFFCC" id="table7">
		<tr>
			<td><br>
			<font face="Courier">./usr/sbin/mypackage<br>
			./tmp/etc/package_config/<br>
			./etc/package_config/ ---(symbolic link)---&gt; 
			../tmp/etc/package_config/<br>
			./tmp/etc/package_config/moreconfig.conf<br>
&nbsp;</font></td>
		</tr>
	</table>
	<p>The above makes the /etc/package_config/ directory a symbolic link to 
	/tmp/package_config/. This would be useful for firmwares that have a 
	read-only /etc file system. On these systems, the configuration files could 
	reside on a ram disk and be emitted at boot-time based on input from some 
	other store of configuration variables, like NVRAM.</p>
	<p><b><font size="4">Step 4:</font></b></p>
	<p>Build the IPK. You're done, now simply build the IPK file with the script 
	provided. It's parameters are:</p>
	<p>MAKE_IPK.SH OUTPUT_PACKAGE_IPK IPK_BASE_DIRECTORY</p>
	<p><i><b>OUTPUT_PACKAGE_IPK</b> </i>: The IPK file to output. If it already 
	exists it will be over-written.<br>
	<i><b>IPK_BASE_DIRECTORY</b> </i>: The directory you created in step 1 and 
	have been working with up until now.</p>
	<p>Example:</p>
	<table border="0" width="100%" bgcolor="#FFFFCC" id="table8">
		<tr>
			<td><br>
			<font face="Courier">make_ipk.sh package.ipk ../package_ipk_dir<br>
&nbsp;</font></td>
		</tr>
	</table>
	<p>&nbsp;</p>
</blockquote>
<p>To support this project:</p>
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<p>&nbsp;</p>
<p><font size="2">This document (c)2006 Jeremy Collake. <br>
All Rights reserved. This document may be freely republished in its unaltered 
and whole form only. Alterations or partial publishing requires approval of 
Jeremy Collake &lt;<a href="mailto:jeremy@bitsum.com">jeremy@bitsum.com</a>&gt;.</font></p>

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