#!/bin/sh
set -e

# $1: dfile, $2: link target, $3: distrib
replace_with_link() {
dfile=$1; ltarget=$2; distrib=$3
temp=$dfile.tmp
# Safely create a symlink to $ltarget at $dfile, first
# making a backup of $dfile (the file being diverted)
# in $distrib.
#
# The cp / ln -s / mv dance avoids having to live without
# $dfile (think: /bin/sh) for even a moment, so applications
# running in parallel can continue without trouble.
# See dash.preinst for details.
if [ -e "$dfile" ]; then
cp -dp "$dfile" "$distrib"
fi
ln -sf "$ltarget" "$temp"
mv -f "$temp" "$dfile"
}

# $1: case, $2: dfile, $3: ltarget [, $4: distrib]
check_divert() {
dfile=$2; ltarget=$3
distrib=${4:-$dfile.distrib}
diverter=$(dpkg-divert --listpackage $dfile)
truename=$(dpkg-divert --truename $dfile)
case "$1" in
true)
if [ "$diverter" != dash ]; then
# Let dpkg-divert error out; we are not taking
# over the diversion, unless we added it
# ourselves on behalf of bash.
if [ "$diverter" = bash ]; then
dpkg-divert --package bash --remove $dfile
else
dpkg-divert --package dash --remove $dfile
# Make sure we die:
echo "This should never be reached"
exit 1
fi

dpkg-divert --package dash --divert $distrib --add $dfile
# remove the old equivalent of $distrib, if it existed:
# or $dfile if there was no previous diversion! -- should never happen, unless preinst failed
if [ -n "$truename" ]; then
rm -f "$truename"
fi
replace_with_link $dfile $ltarget $distrib
fi
;;
false)
if [ "$diverter" = dash ]; then
# Simple hack. We also divert sh(1), remember?
bash=$(echo "$ltarget"|sed 's/dash/bash/')
dpkg-divert --package dash --remove $dfile
# The diversion is added as if we were bash, leaving
# no diversion would lead to a file conflict later
# when re-checked by dpkg
dpkg-divert --package bash --divert $distrib --add $dfile
# ugh? $truename should always be set (to $distrib)
if [ -n "$truename" ]; then
rm -f "$truename"
fi
# Point everything back to bash
replace_with_link $dfile $bash $distrib
fi
;;
ash)
# Code not modified by the NMU:
div=$(dpkg-divert --list $2)
case $div in
'')
;;
*by\ ash)
dst=${div% by ash}
dst=${dst##* to }

# Work around dpkg-divert bug.
if [ -e "$dst" ]; then
mv "$dst" "$dst.dash-tmp"
fi
dpkg-divert --package ash --remove $2
if [ -e "$dst.dash-tmp" ]; then
mv "$dst.dash-tmp" "$dst"
fi

dpkg-divert --package dash --divert $distrib --add $2
if [ "$dst" != $distrib ] && [ -e "$dst" ]; then
mv "$dst" $distrib
fi
ln -sf $3 $2.tmp
mv -f $2.tmp $2
;;
*)
d=${2%/*}
if
[ -h $2 ] && [ -f $2 ] && [ -f $d/$5 ] &&
cmp $2 $d/$5
then
ln -sf $3 $2.tmp
mv -f $2.tmp $2
fi
;;
esac
esac
}

add_shell() {
if ! type add-shell > /dev/null 2>&1; then
return
fi

add-shell /bin/dash
}

reset_default() {
db_fget dash/sh seen
if [ "$RET" = false ]; then
db_reset dash/sh
fi
}

debconf=
if [ -f /usr/share/debconf/confmodule ]; then
. /usr/share/debconf/confmodule
debconf=yes
fi

if [ "$1" = configure ] && [ -z "$2" ]; then
check_divert ash /bin/sh dash '' ash
check_divert ash /usr/share/man/man1/sh.1.gz dash.1.gz \
/usr/share/man/man1/sh.distrib.1.gz ash.1.gz
add_shell
elif [ "$1" = configure ] && dpkg --compare-versions "$2" lt 0.4.18; then
add_shell
fi

if [ $debconf ]; then
reset_default

db_get dash/sh
check_divert "$RET" /bin/sh dash
check_divert "$RET" /usr/share/man/man1/sh.1.gz dash.1.gz \
/usr/share/man/man1/sh.distrib.1.gz
fi

test "$1" = 'configure' || exit 0
test -x /usr/bin/update-menus || exit 0
test -z "$2" || dpkg --compare-versions "$2" lt 0.5.2-3 || exit 0
exec update-menus