Table of Contents

About

This tutorial sums up how to slipstream content into OSX packages (pkg files). The tutorial works on the GrowlMail.pkg package with is meant to install GrowlMail which is incompatible with newer versions of Mail.app under Snow Leopard.

Layout

Unpack

cd ~/Desktop/
pkgutil --expand GrowlMail.pkg GrowlMail

Extract Payload

cd GrowlMail/growlmail.pkg
cat Payload | gzip -d | cpio -id
mkdir ~/Desktop/Bundle
mv GrowlMail.mailbundle ~/Desktop/Bundle
cd ~/Desktop/Bundle

Now you can edit the files or add new files. In this case, we add: 

                <string>588FF7D1-4310-4175-9980-145B7E975C02</string>          
                <string>064442B6-53C0-4A97-B71B-2F111AE4195B</string>

to the ~/Desktop/Bundle/GrowlMail.mailbundle/Contents/Info.plist file.

Package Payload

cd ~/Desktop/Bundle
find . | cpio -o --format odc | gzip -c > ~/Desktop/GrowlMail/growlmail.pkg/Payload
mkbom ./ ~/Desktop/GrowlMail/growlmail.pkg/Bom

Update PackageInfo

Still in ~/Desktop/Bundle we issue: 

du -sk

and then edit ~/Desktop/GrowlMail/growlmail.pkg/PackageInfo and modify the line: 

    <payload installKBytes="1288" numberOfFiles="60"/>

so that installKBytes is the value we obtained with du -sk minus 4 (assuming that the disk is using 4KB blocks).

The result is thus: 

    <payload installKBytes="1300" numberOfFiles="60"/>

Additionally, if we had added or removed files, we have to issue: 

find ~/Desktop/Bundle/ | wc

and update ~/Desktop/GrowlMail/growlmail.pkg/PackageInfo to change numberOfFiles which represents the total number of nodes (files, directories, sockets, etc...) including ..

Pack

cd ~/Desktop
rm GrowlMail.pkg
pkgutil --flatten GrowlMail GrowlMail.pkg

Result

The result is the following package that makes GrowlMail compatible with Snow Leopard including the latest security updates that made GrowlMail incompatible with Mail.app.