From: Thorsten Glaser <tg@mirbsd.org>
Date: Sun, 7 Jun 2009 16:15:44 +0000 (+0000)
Subject: Pad official ISOs to multiples of 256 KiB.
X-Git-Tag: v0.9.18~10
X-Git-Url: https://git.grml.org/?p=grml-live.git;a=commitdiff_plain;h=82345f34a6fd3441ce4c65483c056e078370d6f9

Pad official ISOs to multiples of 256 KiB.

Add “-no-pad” to all mkisofs calls (the mkisofs padding for CD-ROM
readahead support is 32K or 48K usually), and apply padding ourselves
for partition table support. We will use cylinders of 256 KiB (split
in 16 tracks à 32 sectors à 512 bytes) for these. This means that the
padding we add is 512 bytes at least, and a whole 256 KiB at most.

CD-ROM readahead padding is done by the “-pad” option of cdrecord,
which is enabled by default and adds another 300 KiB, but only on
the CD itself.

Signed-off-by: Thorsten Glaser <tg@mirbsd.org>
---

diff --git a/grml-live b/grml-live
index 0e0a639..5e081ba 100755
--- a/grml-live
+++ b/grml-live
@@ -1,7 +1,9 @@
 #!/bin/bash
 # Filename:      grml-live
 # Purpose:       build process script for generating a (grml based) Linux Live-ISO
-# Authors:       grml-team (grml.org), (c) Michael Prokop <mika@grml.org>
+# Authors:       grml-team (grml.org),
+#                (c) Michael Prokop <mika@grml.org>,
+#                (c) Thorsten Glaser <tg@mirbsd.org>
 # Bug-Reports:   see http://grml.org/bugs/
 # License:       This file is licensed under the GPL v2 or any later version.
 ################################################################################
@@ -11,6 +13,13 @@
 export LANG=C
 export LC_ALL=C
 
+# define function getfilesize before "set -e"
+if stat --help >/dev/null 2>&1; then
+	getfilesize='stat -c %s'	# GNU stat
+else
+	getfilesize='stat -f %z'	# BSD stat
+fi
+
 # exit on any error:
 set -e
 
@@ -735,9 +744,16 @@ else
       log "mkisofs -V '${GRML_NAME} ${VERSION}' -publisher 'grml-live | grml.org' -l -r -J -no-emul-boot -boot-load-size 4 -boot-info-table -b $BOOT_FILE -o ${ISO_OUTPUT}/${ISO_NAME} ."
       mkisofs -V "${GRML_NAME} ${VERSION}" -publisher 'grml-live | grml.org' \
               -l -r -J -no-emul-boot -boot-load-size 4 -boot-info-table    \
-              -b $BOOT_FILE \
+              -b $BOOT_FILE -no-pad \
               -o "${ISO_OUTPUT}/${ISO_NAME}" . ; RC=$?
 
+      # pad the output ISO to multiples of 256 KiB for partition table support
+      siz=$($getfilesize "${ISO_OUTPUT}/${ISO_NAME}")
+      cyls=$((siz / 512 / 32 / 16 + 1))		# C=$cyls H=16 S=32
+      siz=$((cyls * 16 * 32 * 512))		# size after padding
+      dd if=/dev/zero bs=1 count=1 seek=$((siz - 1)) \
+         of="${ISO_OUTPUT}/${ISO_NAME}" 2>/dev/null
+
       # support disabling hybrid ISO image
       if [ "$HYBRID_METHOD" = "disable" ] ; then\
          log "Skipping creation of hybrid ISO file as requested via HYBRID_METHOD=disable"
diff --git a/remaster/grml-live-remaster b/remaster/grml-live-remaster
index 9d62cf7..15aec22 100755
--- a/remaster/grml-live-remaster
+++ b/remaster/grml-live-remaster
@@ -1,7 +1,10 @@
 #!/bin/sh
 # Filename:      grml-live-remaster
 # Purpose:       remaster a grml from the live cd
-# Authors:       grml-team (grml.org), (c) Michael Schierl <schierlm@gmx.de>, (c) Michael Prokop <mika@grml.org>
+# Authors:       grml-team (grml.org),
+#                (c) Michael Schierl <schierlm@gmx.de>,
+#                (c) Michael Prokop <mika@grml.org>,
+#                (c) Thorsten Glaser <tg@mirbsd.org>
 # Bug-Reports:   see http://grml.org/bugs/
 # License:       This file is licensed under the GPL v2 or any later version.
 ################################################################################
@@ -9,6 +12,13 @@
 # this script currently lacks LOTS of error checking code... any help welcome...
 ################################################################################
 
+# define function getfilesize before "set -e"
+if stat --help >/dev/null 2>&1; then
+	getfilesize='stat -c %s'	# GNU stat
+else
+	getfilesize='stat -f %z'	# BSD stat
+fi
+
 set -e # exit on any error
 
 VERSION='0.0.2'
@@ -20,7 +30,7 @@ GRML_LIVE_EDITOR=${VISUAL:-${EDITOR:-vi}}
 # }}}
 
 # make sure we have what we need {{{
-check4progs mkisofs mksquashfs || exit 1
+check4progs mkisofs mksquashfs stat || exit 1
 check4root || exit 1
 # }}}
 
@@ -109,9 +119,17 @@ else
 fi
 
 mkisofs -b $ISOLINUX -no-emul-boot -c $ISOLINUX_BOOTCAT \
-        -boot-info-table -l -r -J -o "$1" /remaster/iso
+        -boot-info-table -boot-load-size 4 -no-pad \
+        -l -r -J -o "$1" /remaster/iso
+# pad for partition table
+siz=$($getfilesize "$1")
+cyls=$((siz / 512 / 32 / 16 + 1))	# C=$cyls H=16 S=32 (= 256 KiB units)
+siz=$((cyls * 16 * 32 * 512))		# size after padding
+dd if=/dev/zero bs=1 count=1 seek=$((siz - 1)) of="$1" 2>/dev/null
 rm -R /remaster/iso
 
+# here is the place to apply bootgrub.mksh ☺
+
 echo ""
 echo "ISO generation complete:"
 ls --color -l "$1"