#! /bin/sh

# Copyright (C) 2008-2017 Alexandre Oliva <lxoliva@fsfla.org>

# This program is part of GNU Linux-libre, a GNU project that
# publishes scripts to clean up Linux so as to make it suitable for
# use in the GNU Project and in Free System Distributions.

# 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-main - prepare a GNU Linux-libre tarball out of a non-libre
# Linux tarball.  It expects the Linux release (mver, say 3.0) as the
# first argument, the gnu 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-libre-$kver-gnu$extra.tar.bz2.
# An uncompressed xdelta that produces linux-libre-$kver-gnu$extra.tar
# out of linux-$kver.tar is put in linux-libre-$kver-gnu$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.

# xdelta version 3 uses different command line syntax, and it switched
# to the more standardized but less efficient vcdiff file format.
# This script will also produce a vcdiff file if xdelta3 is present,
# and it expects the xdelta program to use the version 1 syntax.

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

# The tar files and binary deltas are finally compressed with bzip2,
# and optionally with lzip and xz too, if the compressors are
# available.

# 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

# We don't want e.g. diff output translations to affect us.
LC_ALL=C; export LC_ALL
LANGUAGE=C; export LANGUAGE

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

if test -f linux-$kver.tar; then
  zext=tar     zcmd=
elif test -f linux-$kver.tar.bz2; then
  zext=tar.bz2 zcmd=bunzip2
elif test -f linux-$kver.tar.xz; then
  zext=tar.xz  zcmd=unxz
elif test -f linux-$kver.tar.lz; then
  zext=tar.lz  zcmd="lzip -d"
elif test -f linux-$kver.tar.gz; then
  zext=tar.gz  zcmd=gunzip
elif test -f linux-$kver.tgz; then
  zext=tgz     zcmd=gunzip
else
  echo linux-$kver.tar not found, tried .bz2, .xz, .lz, .gz and .tgz too >&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=" $deblob | sed 's, *#.*,,'`
if test "$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-libre-$kver-$gnu.tar.bz2 \
  linux-libre-$kver-$gnu.tar.bz2.asc \
  linux-libre-$kver-$gnu.tar.bz2.sign \
  linux-libre-$kver-$gnu.tar.xz \
  linux-libre-$kver-$gnu.tar.xz.asc \
  linux-libre-$kver-$gnu.tar.xz.sign \
  linux-libre-$kver-$gnu.tar.lz \
  linux-libre-$kver-$gnu.tar.lz.asc \
  linux-libre-$kver-$gnu.tar.lz.sign \
  linux-libre-$kver-$gnu.tar \
  linux-libre-$kver-$gnu.tar.asc \
  linux-libre-$kver-$gnu.tar.sign \
  linux-libre-$kver-$gnu.patch \
  linux-libre-$kver-$gnu.log \
  linux-libre-$kver-$gnu.vcdiff \
  linux-libre-$kver-$gnu.vcdiff.bz2 \
  linux-libre-$kver-$gnu.vcdiff.bz2.asc \
  linux-libre-$kver-$gnu.vcdiff.bz2.sign \
  linux-libre-$kver-$gnu.vcdiff.xz \
  linux-libre-$kver-$gnu.vcdiff.xz.asc \
  linux-libre-$kver-$gnu.vcdiff.xz.sign \
  linux-libre-$kver-$gnu.vcdiff.lz \
  linux-libre-$kver-$gnu.vcdiff.lz.asc \
  linux-libre-$kver-$gnu.vcdiff.lz.sign \
  linux-libre-$kver-$gnu.xdelta \
  linux-libre-$kver-$gnu.xdelta.bz2 \
  linux-libre-$kver-$gnu.xdelta.bz2.asc \
  linux-libre-$kver-$gnu.xdelta.bz2.sign \
  linux-libre-$kver-$gnu.xdelta.xz \
  linux-libre-$kver-$gnu.xdelta.xz.asc \
  linux-libre-$kver-$gnu.xdelta.xz.sign \
  linux-libre-$kver-$gnu.xdelta.lz \
  linux-libre-$kver-$gnu.xdelta.lz.asc \
  linux-libre-$kver-$gnu.xdelta.lz.sign \
; do
  if test -f $f; then
    echo $f already exists >&2
    exit 1
  fi
  cleanup="$cleanup $f"
done

for d in \
  linux-$kver \
  linux-libre-$kver-$gnu \
  orig-linux-$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

if test -n "$zcmd"; then
  echo Uncompressing linux-$kver.$zext into linux-$kver.tar
  rm -rf linux-$kver.tar
  cleanup="$cleanup linux-$kver.tar"
  $zcmd < linux-$kver.$zext > linux-$kver.tar
fi

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

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

rm -f linux-libre-$kver-$gnu.log linux-libre-$kver-$gnu.log.tmp
echo Deblobbing within linux-libre-$kver-$gnu, saving output to linux-libre-$kver-$gnu.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-libre-$kver-$gnu && /bin/sh ../$deblob $force) 2>&1; then
  mv linux-libre-$kver-$gnu.log.tmp linux-libre-$kver-$gnu.log
fi | tee linux-libre-$kver-$gnu.log.tmp
if test ! -f linux-libre-$kver-$gnu.log; then
  mv linux-libre-$kver-$gnu.log.tmp linux-libre-$kver-$gnu.log
  echo $deblob failed, aborting >&2
  exit 1
fi
rm -f linux-libre-$kver-$gnu.patch

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

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

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

echo Adding modified or added files to linux-libre-$kver-$gnu.tar
rm -rf orig-linux-$kver
mv linux-$kver orig-linux-$kver
mv linux-libre-$kver-$gnu linux-$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-libre-$kver-$gnu.tar

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

echo Creating vcdiff between linux-$kver.tar and linux-libre-$kver-$gnu.tar
xdelta3 -e -9 -S djw -s linux-$kver.tar linux-libre-$kver-$gnu.tar linux-libre-$kver-$gnu.vcdiff || : # don't fail if xdelta3 is not present

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

cleanup="linux-libre-$kver-$gnu.tar linux-libre-$kver-$gnu.xdelta"

echo Compressing binary deltas and linux-libre-$kver-$gnu.tar
rm -f linux-$kver.tar
if test -f linux-libre-$kver-$gnu.xdelta; then
  bzip2 -k9 linux-libre-$kver-$gnu.xdelta
  xz -k9 linux-libre-$kver-$gnu.xdelta || :
  lzip -k9s64MiB linux-libre-$kver-$gnu.xdelta || :
fi
bzip2 -k9 linux-libre-$kver-$gnu.tar
xz -k9 linux-libre-$kver-$gnu.tar || :
lzip -k9s64MiB linux-libre-$kver-$gnu.tar || :

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

rm -f $cleanup
cleanup=
trap 'status=$?; (exit $status); exit' 0 1 2 15

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

exit 0