The build_installer.sh script
=============================

The 'build_installer.sh' script has the following characteristics:

* It works for all Slackware ARCH'es (tested with i586 and x86_64)
* It can be started from any directory, because resulting output files will
be written to the current directory. This means that the script directory
can be on a read-only filesystem.
* It can update a pre-existing initrd.img file with kernel modules
for a new kernel in one single command
* It can build a complete Slackware installer set (initrd.img , usbboot.img
and pxelinux.cfg_default files) from scratch
* It can create a tarball containing a 'skeleton' for an initrd, which does
not contain any ARCH specific binary code; only the directory structure,
symlinks, configuration files and scripts. This skeleton can be used as a
base for creating a new initrd from scratch, in which case no previous
initrd.img file needs to be present to obtain the scripts etc from. The
skeleton file will be called 'skeleton_initrd.tar.gz' and will be written to
the current directory.

Command line parameters and detailed usage
==========================================

Running "./build_installer.sh -h" shows this message:

# ----------------------------------------------------------------------------#
Usage: build_installer.sh <parameters>
Parameters:
-h|--help Show this help
-c|--compressmods Compress the kernel modules inside the initrd.img
-m|--multiple Multiple initrd files (for SMP and non-SMP kernels)
-n|--netmods Add network modules to the initrd
-nc|--no-compressmods Do _not_ compress kernel modules
-nm|--no-multiple Do _not_ create multiple initrd files
-nn|--no-netmods Do _not_ add network modules to the initrd
-np|--no-pcmciamods Do _not_ add pcmcia modules to the initrd
-nr|--no-recompile Do _not_ recompile /re-add binaries
-nu|--no-usbboot Do _not_ create a USB boot image
-p|--pcmciamods Add pcmcia modules to the initrd
-q|--quiet Be (fairly) quiet during progress
-r|--recompile Recompile /re-add binaries (busybox,bash,dropbear as
well as any required bin/lib from Slackware packages)
-s|--skeleton Stop after creating a skeleton_initrd.tar.gz
(which only contains directories and scripts)
-u|--usbboot Create a USB boot image
-v|--verbose Be (very) verbose during progress
-I|--initrd <file> Specify location of the initrd.img file
-S|--slackroot <dir> Specify location of the Slackware directory tree

Actions to be taken (ARCH=x86_64):
* Be (very) verbose during progress
* Recompile /re-add binaries
* Add network modules to the initrd
* Add pcmcia modules to the initrd
* Compress all kernel modules
* Do _not_ split the initrd
* Create a USB boot image

Use Slackware root:
/mnt/nfs/door/non-public/slackware-current
Use initrd file:
/mnt/nfs/door/non-public/slackware-current/isolinux/initrd.img

# Note: [1] If you want to build your own specific bash, busybox and dropbear #
# instead of using the sources provided by the Slackware tree, #
# you should have these sources ready below #
# ./sources/{bash,busybox,dropbear} #
# Delete the directory if you don't want to use it! #
# [2] If you want to use your own _skeleton_ initrd (containing only #
# the directory layout plus all the scripts) you just make it #
# available as ./sources/initrd/skeleton_initrd.tar.gz #
# #
# The script will look for the directory 'sources' first in your #
# working directory, and next in the script's directory (whatever is #
# found in your working directory takes precedence). #
# ----------------------------------------------------------------------------#


The default actions performed by the script may be different for each ARCH -
they are parametrized in the script and can be modified by adding commandline
switches to the script's invocation. The examples below use explicit
switches to make them are valid commands for all ARCHes.

Examples of usage
==================

(1) Specify a different ARCH than the default, and point the script to a
non-default root directory of the Slackware tree:

# ARCH=i486 SLACKROOT=~ftp/pub/slackware-current ./build_installer.sh

(2) Slackware gets a new kernel, and the initrd needs to be updated with
new modules:

# ./build_installer.sh -n -p -nr -u

This command adds updated net/pcmcia modules to the initrd.img (and removes
old modules of course), will not recompile any of the binary software inside
(notably bash, busybox and dropbear) and will create a USB boot image as
the final action. Output files are created in the current directory.

(3) Strip Slackware's existing initrd.img until it's skeleton remains:

# ./build_installer.sh -s

This command takes the file '$SLACKROOT/isolinux/initrd.img' and writes
the resulting 'skeleton_initrd.tar.gz' to the current directory.
NOTE: If you ever need to create a skeleton tarball, be sure to use a 32bit
slackware tree's initrd.img file for this. That way, the pathname
'slackware' will be present in the tarball, and the build_installer.sh
script will be able to translate that to an ARCH-specific directory
name like for instance "slackware64" for the x86_64 platform.
Even on x86_64 you can run this command:

# ARCH=i486 SLACKROOT=/stuff/slackware32 ./build_installer.sh -s

to use a 32bit initrd.img file as the source.

(4) Create a new initrd.img file from scratch, using a pre-existing skeleton
initrd tarball, and my own busybox sources/patches (while using the sources
for bash and dropbear that are present in the slackware directory tree):

# mkdir -p ./sources/{busybox,initrd}
# cp /home/slackware64/installer/skeleton_initrd.tar.gz ./sources/initrd/
# cp -a my_busybox_stuff/* ./sources/busybox/
# ARCH=x86_64 ./build_installer.sh -c -n -p -u

This will build initrd.img from the ground up, compiling binaries for bash,
busybox and dropbear (used in the installer) from their sources and
extracting library/binary files from several of the Slackware packages
found in the slackware directory tree. Network and pcmcia kernel modules
will be added and compressed (cutting down the client's RAM requirements
with 9 MB during installation), and finally a USB bootable image named
'usbboot.img' will be created.