From 7af741640c38d865d91a9adb884e713b84af6ca5 Mon Sep 17 00:00:00 2001
From: Eric Hameleers <alien@slackware.com>
Date: Wed, 13 Apr 2016 22:00:23 +0200
Subject: Use XZ compression for the initrd instead of GZIP.

This shrinks the initrd back from 22 to 17 MB in size.
Also, a redundant copy of the initrd was removed from the
'0000-slackware_boot' module, reducing the ISO size with an
additional 17 MB.

These two modifications compensate for the increased size due to
addition of network modules and firmware (which are needed for
network boot).

Goal reached: the XFCE ISO still fits on CDROM media.
---
 make_slackware_live.sh | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

(limited to 'make_slackware_live.sh')

diff --git a/make_slackware_live.sh b/make_slackware_live.sh
index 6fe3b34..7734675 100755
--- a/make_slackware_live.sh
+++ b/make_slackware_live.sh
@@ -179,6 +179,11 @@ NETEXCL="appletalk arcnet bonding can dummy.ko hamradio hippi ifb.ko irda macvla
 # ---------------------------------------------------------------------------
 #
 
+# What compression to use for the initrd?
+# Default is xz with CRC32 (the kernel's XZ decoder does not support CRC64),
+# the alternative is gzip (which adds  ~30% to the initrd size).
+COMPR=${COMPR:-"xz --check=crc32"}
+
 # What compression to use for the squashfs modules?
 # Default is xz, alternatives are gzip, lzma, lzo:
 SXZ_COMP=${SXZ_COMP:-"xz"}
@@ -231,6 +236,15 @@ cleanup() {
 }
 trap 'echo "*** $0 FAILED at line $LINENO ***"; cleanup; exit 1' ERR INT TERM
 
+# Uncompress the initrd based on the compression algorithm used:
+uncompressfs () {
+  if $(file "${1}" | grep -qi ": gzip"); then
+    gzip -cd "${1}"
+  elif $(file "${1}" | grep -qi ": XZ"); then
+    xz -cd "${1}"
+  fi
+}
+
 #
 # Return the full pathname of first package found below $2 matching exactly $1:
 #
@@ -1101,7 +1115,7 @@ if [ -f ${LIVE_ROOTDIR}/boot/vmlinuz-huge-* ]; then
   # and move them to a single directory in the ISO:
   mkdir -p  ${LIVE_ROOTDIR}/usr/share/${LIVEMAIN}
   cd  ${LIVE_ROOTDIR}/usr/share/${LIVEMAIN}
-    gunzip -cd ${DEF_SL_PKGROOT}/../isolinux/initrd.img | cpio -i -d -H newc --no-absolute-filenames usr/lib/setup/* sbin/probe sbin/fixdate
+    uncompressfs ${DEF_SL_PKGROOT}/../isolinux/initrd.img | cpio -i -d -H newc --no-absolute-filenames usr/lib/setup/* sbin/probe sbin/fixdate
     mv -i usr/lib/setup/* sbin/probe sbin/fixdate .
     rm -r usr sbin
   cd -
@@ -1558,7 +1572,7 @@ KVER=$(ls --indicator-style=none ${LIVE_ROOTDIR}/lib/modules/ |head -1)
 
 # Create an initrd for the generic kernel, using a modified init script:
 echo "-- Creating initrd for kernel-generic $KVER ..."
-chroot ${LIVE_ROOTDIR} /sbin/mkinitrd -c -w ${WAIT} -l us -o /boot/initrd_${KVER}.gz -k ${KVER} -m ${KMODS} -L -C dummy 1>${DBGOUT} 2>${DBGOUT}
+chroot ${LIVE_ROOTDIR} /sbin/mkinitrd -c -w ${WAIT} -l us -o /boot/initrd_${KVER}.img -k ${KVER} -m ${KMODS} -L -C dummy 1>${DBGOUT} 2>${DBGOUT}
 # Modify the initrd content for the Live OS:
 cat $LIVE_TOOLDIR/liveinit | sed \
   -e "s/@LIVEMAIN@/$LIVEMAIN/g" \
@@ -1594,7 +1608,9 @@ if [ "$NFSROOTSUP" = "YES" ]; then
     2>/dev/null || true
 fi
 # Wrap up the initrd.img again:
-chroot ${LIVE_ROOTDIR} /sbin/mkinitrd 1>/dev/null 2>${DBGOUT}
+( cd ${LIVE_ROOTDIR}/boot/initrd-tree
+  find . | cpio -o -H newc | $COMPR >${LIVE_ROOTDIR}/boot/initrd_${KVER}.img 2>${DBGOUT}
+)
 rm -rf ${LIVE_ROOTDIR}/boot/initrd-tree
 
 # ... and cleanup these mounts again:
@@ -1602,15 +1618,19 @@ umount ${LIVE_ROOTDIR}/{proc,sys,dev} || true
 umount ${LIVE_ROOTDIR} || true
 # Paranoia:
 [ ! -z "${LIVE_BOOT}" ] && rm -rf ${LIVE_BOOT}/{etc,tmp,usr,var} 1>${DBGOUT} 2>${DBGOUT}
-# Squash the boot directory into its own module:
-mksquashfs ${LIVE_BOOT} ${LIVE_MOD_SYS}/0000-${DISTRO}_boot-${SL_VERSION}-${SL_ARCH}.sxz -noappend -comp ${SXZ_COMP} -b 1M
 
-# Copy kernel files and tweak the syslinux configuration:
+# Copy kernel and move the modified initrd (we do not need it in the Live OS).
 # Note to self: syslinux does not 'see' files unless they are DOS 8.3 names?
 rm -rf ${LIVE_STAGING}/boot
 mkdir -p ${LIVE_STAGING}/boot
 cp -a ${LIVE_BOOT}/boot/vmlinuz-generic*-$KGEN ${LIVE_STAGING}/boot/generic
-cp -a ${LIVE_BOOT}/boot/initrd_${KVER}.gz ${LIVE_STAGING}/boot/initrd.img
+mv ${LIVE_BOOT}/boot/initrd_${KVER}.img ${LIVE_STAGING}/boot/initrd.img
+
+# Squash the boot directory into its own module:
+mksquashfs ${LIVE_BOOT} ${LIVE_MOD_SYS}/0000-${DISTRO}_boot-${SL_VERSION}-${SL_ARCH}.sxz -noappend -comp ${SXZ_COMP} -b 1M
+
+# Copy the syslinux configuration.
+# The next block checks here for a possible UEFI grub boot image:
 cp -a ${LIVE_TOOLDIR}/syslinux ${LIVE_STAGING}/boot/
 
 # EFI support always for 64bit architecture, but conditional for 32bit.
-- 
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