#! /bin/sh

# Copyright (C) 2008, 2009 Alexandre Oliva <lxoliva@fsfla.org>

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
# USA

# deblob.sh - prepare a linux-libre tarball out of a non-libre Linux
# tarball.  It expects the Linux release (mver, say 2.6.25) as the
# first argument, the libre sub-release (extra) as the second optional
# argument, and the patch release (sver, say .13) as an optional third
# argument.  mver and sver are pasted together to form kver.

# linux-$kver.tar.bz2 and deblob-$mver must exist in the current
# directory, and the line that sets kver and extra in deblob-$mver
# must match mver and extra.

# The resulting tarball is put in linux-$kver-libre$extra.tar.bz2, and
# an uncompressed xdelta that produces linux-$kver-libre$extra.tar out
# of linux-$kver.tar is created as linux-$kver-libre$extra.xdelta.
# This xdelta can be distributed to enable third parties to easily
# reconstruct the binary tarball starting out of sources downloaded
# from kernel.org, but without distributing non-Free Software
# yourself, because xdelta (unlike patches) is not reversible: the
# removed bits are not present in it at all.

# To enable you to check the differences between the tarballs, a patch
# file is generated in linux-$kver-libre$extra.patch.  This patch file
# contains the non-Free blobs, even though in reversed form, so its
# distribution is discouraged.

# At the end, the script attempts to generate a digital signature for
# the newly-created tarball.  This is the last thing the script does,
# so interrupting it at that point to skip the signing won't fail to
# do anything else.

# It is safe to interrupt the script at any other point.  When it gets
# a ^C (other than during signing), it starts cleaning up all of its
# temporary and output files.  If you insist, it may leave junk
# behind, and then it will refuse to run again before you clean it up
# by hand.  It takes extra care to avoid overwriting useful files.

# If deblob-$mver finds any unexpected situation, it will error out,
# and then deblob-main will quit.  Pass --force to deblob-main, before
# any other argument, for deblob-main to ignore any such situations.

case $1 in
--force) force=--force; shift;;
*) force=;;
esac

mver=$1 extra=$2 sver=$3
kver=$mver$sver libre=libre$extra
deblob= dir=`echo "$0" | sed 's,[^/]*$,,;s,^$,.,;s,/*$,,'`

if test ! -f linux-$kver.tar.bz2; then
  echo linux-$kver.tar.bz2 does not exist >&2
  exit 1
fi

if test -f deblob-$mver; then
  deblob=deblob-$mver
elif test -f deblob; then
  deblob=deblob
elif test -f $dir/deblob-$mver; then
  cp $dir/deblob-$mver deblob
  deblob=deblob
else
  echo deblob does not exist >&2
  exit 1
fi

x1="kver=$mver extra=$extra"
x2=`grep "^kver=[^ ]* extra=" $deblob`
if test "$x1" = "$x2"; then
  :
else
  echo deblob script does not match command-line arguments >&2
  echo expected: $x1 >&2
  echo found   : $x2 >&2
  exit 1
fi

cleanup=

for f in \
  linux-$kver-$libre.tar.bz2 \
  linux-$kver-$libre.tar.bz2.asc \
  linux-$kver-$libre.tar.bz2.sign \
  linux-$kver-$libre.tar.lz \
  linux-$kver-$libre.tar.lz.asc \
  linux-$kver-$libre.tar.lz.sign \
  linux-$kver.tar \
  linux-$kver-$libre.tar \
  linux-$kver-$libre.patch \
  linux-$kver-$libre.log \
  linux-$kver-$libre.xdelta \
  linux-$kver-$libre.xdelta.asc \
  linux-$kver-$libre.xdelta.sign \
; do
  if test -f $f; then
    echo $f already exists >&2
    exit 1
  fi
  cleanup="$cleanup $f"
done

for d in \
  linux-$kver \
  linux-$kver-$libre \
  orig-linux-$kver \
; do
  if test -d $d; then
    echo $d already exists >&2
    exit 1
  fi
  cleanup="$cleanup $d"
done

if test -f $dir/deblob-$kver; then
  if cmp $dir/deblob-$kver $deblob; then
    :
  else
    echo $dir/deblob-$kver and $deblob are different >&2
    exit 1
  fi
fi

if test ! -f deblob-check; then
  if test -f $dir/deblob-check; then
    cp $dir/deblob-check deblob-check
  fi
else
  if test -f $dir/deblob-check; then
    if cmp $dir/deblob-check deblob-check; then
      :
    else
      echo $dir/deblob-check and deblob-check are different >&2
      exit 1
    fi
  fi
fi

trap "status=$?; echo cleaning up...; rm -rf $cleanup; (exit $status); exit" 0 1 2 15

set -e

echo Uncompressing linux-$kver.tar.bz2 into linux-$kver.tar
rm -rf linux-$kver linux-$kver.tar
bunzip2 < linux-$kver.tar.bz2 > linux-$kver.tar

echo Extracing linux-$kver.tar into linux-$kver
tar -xf linux-$kver.tar
rm -rf linux-$kver-$libre linux-$kver-$libre.tar

echo Copying linux-$kver to linux-$kver-$libre
cp linux-$kver.tar linux-$kver-$libre.tar
cp -lR linux-$kver/. linux-$kver-$libre

rm -f linux-$kver-$libre.log linux-$kver-$libre.log.tmp
echo Deblobbing within linux-$kver-$libre, saving output to linux-$kver-$libre.log
# We can't just pipe deblob into tee, for then we fail to detect 
# error conditions.  Use file renaming to tell whether we succeeded.
if (cd linux-$kver-$libre && /bin/sh ../$deblob $force) 2>&1; then
  mv linux-$kver-$libre.log.tmp linux-$kver-$libre.log
fi | tee linux-$kver-$libre.log.tmp
if test ! -f linux-$kver-$libre.log; then
  mv linux-$kver-$libre.log.tmp linux-$kver-$libre.log
  echo $deblob failed, aborting >&2
  exit 1
fi
rm -f linux-$kver-$libre.patch

# Do not copy these scripts for now, deblob-check regards itself as a blob.
# cp -p $0 $deblob deblob-check linux-$kver-$libre

echo Generating linux-$kver-$libre.patch
diff -druN linux-$kver linux-$kver-$libre > linux-$kver-$libre.patch || :

echo Removing removed or modified files from linux-$kver-$libre.tar
diff -rq linux-$kver linux-$kver-$libre |
sed -n "
  s,^Only in \\(linux-$kver\\(/.*\\)\\?\\): \\(.*\\),\1/\3,p;
  s,^Files \\(linux-$kver\\)/\\(.*\\) and \\1-$libre/\\2 differ,\\1/\\2,p;
" |
xargs tar --delete -f linux-$kver-$libre.tar

echo Adding modified or added files to linux-$kver-$libre.tar
rm -rf orig-linux-$kver
mv linux-$kver orig-linux-$kver
mv linux-$kver-$libre linux-$kver
diff -rq orig-linux-$kver linux-$kver |
sed -n "
  s,^Files orig-\\(linux-$kver/.*\\) and \\1 differ,\\1,p;
  s,^Only in \\(linux-$kver\\(/.*\\)\\?\\): \\(.*\\),\\1/\\3,p;
" |
xargs tar --append -f linux-$kver-$libre.tar

echo Wiping out extracted trees
rm -rf linux-$kver orig-linux-$kver

echo Creating xdelta between linux-$kver.tar and linux-$kver-$libre.tar
xdelta delta -0 linux-$kver.tar linux-$kver-$libre.tar linux-$kver-$libre.xdelta || : # xdelta returns nonzero on success

echo Compressing linux-$kver-$libre.tar and linux-$kver-$libre.xdelta
rm -f linux-$kver.tar
lzip -k9 linux-$kver-$libre.tar
bzip2 -9 linux-$kver-$libre.tar
if test -f linux-$kver-$libre.xdelta; then
  lzip -k9 linux-$kver-$libre.xdelta
  bzip2 -9 linux-$kver-$libre.xdelta
fi

trap "status=$?; (exit $status); exit" 0 1 2 15

echo Done except for signing, feel free to interrupt
for f in \
  linux-$kver-$libre.tar.bz2 \
  linux-$kver-$libre.tar.lz \
  linux-$kver-$libre.xdelta.bz2 \
  linux-$kver-$libre.xdelta.lz \
; do
  if test -f $f; then
    gpg -a --detach-sign $f
    mv $f.asc $f.sign
  fi
done

echo All set, please review linux-$kver-$libre.patch

exit 0