#!/bin/sh

set -e

. /usr/share/debconf/confmodule
db_version 2.0

now=`date +%Y%m%dT%H%M`
logdir=/var/lib/insserv
logfile="$logdir/run-$now.log"
flagfile=/etc/init.d/.legacy-bootordering

# Make sure insserv is in path
PATH=/sbin:$PATH

# Based on code from dash postinst
check_divert() {
    package=insserv
    div=$(dpkg-divert --list $2)
    distrib=${4:-$2.distrib}
    case "$1" in
    false)
        if [ -n "$div" ] && [ -z "${div%%*by $package}" ]; then
	    mv $distrib $2
	    dpkg-divert --package $package --remove $2
	fi
	;;
    status) # Return true if the divert is in effect
        if [ -n "$div" ] && [ -z "${div%%*by $package}" ]; then
            :
	else
	    false
	fi
    esac
}


convert_rc_s_to_k() {
  runlevel=$1
  for link in $(cd $target/etc/rc$runlevel.d; ls S* || true); do
      set `echo $link|sed "s%S\(..\)\(.*\)%\1 \2%"`
      seq=$1
      service=$2
      mv $target/etc/rc$runlevel.d/$link $target/etc/rc$runlevel.d/K$seq$service
  done
}

add_problematic() {
    msg="$1"
    if [ -z "$PROBLEMATIC" ] ; then
	PROBLEMATIC="$msg"
    else
	PROBLEMATIC="$PROBLEMATIC, $msg"
    fi
}

is_unsafe_to_activate() {
    retval=1
    # Refuse to convert when there are obsolete init.d scripts left
    # behind, as these tend to confuse the boot sequence.
    echo "info: Checking if it is safe to convert to dependency based boot." 1>&2
    for package in $(dpkg -S $(find /etc/init.d -type f -perm /+x) \
                     2>/dev/null | cut -d: -f1 | sort -u); do
        obsolete_initscripts=$(dpkg-query -W -f='${Conffiles}\n' $package | \
	    grep 'obsolete$' | grep -o '/etc/init.d/[^ ]\+') || :
        if [ "$obsolete_initscripts" ]; then
            for initscript in $obsolete_initscripts; do
                if [ -e "$initscript" ]; then
                    retval=0
                    add_problematic "package $package left obsolete init.d script behind"
                fi
            done
        fi
    done

    # Refuse to migrate if insserv find problems, like loops,
    # duplicate provides, script providing system facility or missing
    # header completely.
    insserv -nv > $logfile 2>&1 || true
    errstr='There is a loop between|loop involving service|already provided!|provides system facility|missing LSB tags'
    if egrep -q "$errstr" $logfile ; then
	msg=$(egrep "$errstr" $logfile | sed 's/$/, /' | tr "\n" " ")
	retval=0
	add_problematic "$msg"

	# If insserv found problems, report removed but not purged
	# packages, as their dependency information is probably
	# outdated or missing, leading to incorrect ordering.
	for package in $(dpkg -l $(dpkg -S /etc/init.d/* 2>/dev/null |
		cut -d: -f1 |sort -u)|grep ^rc|awk '{print $2}') ; do
	    retval=0
	    add_problematic "package $package removed but not purged"
	done
    fi
    rm $logfile
    return $retval
}

activate_insserv() {
    # Save the current sequence numbers in
    # /var/lib/update-rc.d/.  This directory will be updated
    # when update-rc.d is called, to make it possible to migrate away
    # from dependency based boot sequencing.  If some script is
    # missing in /var/lib/update-rc.d/, one will have to
    # reconfigure the package it belong to for update-rc.d to update
    # the content in /var/lib/update-rc.d/.
    /usr/share/sysv-rc/saveconfig -s /var/lib/update-rc.d

    echo "info: Reordering boot system, log to $logfile" 1>&2
    (
	echo "info: Converting rc0.d/S* and rc6.d/S* to K*." 1>&2
	convert_rc_s_to_k 0
	convert_rc_s_to_k 6
	echo "info: running insserv" 1>&2
	insserv -v
    ) > $logfile 2>&1

    # Indicate that system is no longer using the legacy ordering
    rm $flagfile

    return 0
}

try_to_convert() {
    PROBLEMATIC=""
    if is_unsafe_to_activate ; then
	# Make sure the note is seen every time
	db_fset sysv-rc/unable-to-convert seen false
	db_subst sysv-rc/unable-to-convert PROBLEMATIC "$PROBLEMATIC"
	db_input critical sysv-rc/unable-to-convert || [ $? -eq 30 ]
	db_go || true
	return 1
    else
	# Ask if the legacy boot sequence should be converted to
	# dependency based.

	# Priority is critical during upgrades, to give those with
	# existing installations a good  chance of seeing and rejecting
	# the migration.
	db_input critical sysv-rc/convert-legacy || [ $? -eq 30 ]

	db_go
	db_get sysv-rc/convert-legacy || true
	if [ true = "$RET" ] ; then
	    if activate_insserv ; then
		echo "success: Enabled dependency based boot system." 1>&2
	    else
		echo "error: Something failed while migrating." 1>&2
	    fi
	else
	    echo "warning: Asked to not convert legacy boot sequence to dependency based boot sequencing." 1>&2
	fi
    fi
}

case "$1" in
    configure)
        # Remove divert created by insserv during upgrades if it
        # exist.  It was dropped in insserv 1.12.0-11 converted since
        # sysvinit 2.87dsf-3, 2009-08-19.
        if [ -f /var/run/sysv-rc.upgrade ]; then
	    lastver=$(cat /var/run/sysv-rc.upgrade)
	    if dpkg --compare-versions "$2" lt 2.87dsf-3 ; then
		if check_divert status /usr/sbin/update-rc.d \
		    /usr/sbin/update-rc.d-insserv ; then
		    check_divert false /usr/sbin/update-rc.d \
			/usr/sbin/update-rc.d-insserv
		    rm /var/lib/insserv/using-insserv
		else
		    touch $flagfile
		fi
	    fi
	    rm /var/run/sysv-rc.upgrade
	fi

	# Detect migrations away from file-rc, where the legacy boot
	# ordering is used but the flag file to indicated legacy boot
	# ordering is missing.  Can not do this in preinst, as preinst
	# might be executed before the postinst of file-rc creatingthe
	# files in /etc/rc?.d/.
	for f in /etc/rc0.d/S* ; do
	    if [ ! -f $flagfile ] && [ -f $f ] ; then
		touch $flagfile
		break
	    fi
	done

	if [ -f $flagfile ] && [ -n "$USEINSSERV" ]; then
	    # Still using legacy ordering, try to convert
	    if try_to_convert ; then
		:
	    else
		cat 1>&2 <<EOF

error: Unable to migrate to dependency based boot sequencing.
error: Problems detected: $PROBLEMATIC

See http://wiki.debian.org/LSBInitScripts/DependencyBasedBoot for
more information about dependency based boot sequencing. To
reattempt the migration process run 'dpkg-reconfigure sysv-rc'.

EOF
	    fi
	fi
	if dpkg --compare-versions "$2" lt 2.87dsf-5 ; then
	    removedfiles=$(grep -l 'remove$' /var/lib/update-rc.d/* 2>/dev/null || true)
	    if [ "$removedfiles" ] ; then
		rm $removedfiles
	    fi
	fi
	;;
    *)
	;;
esac

db_stop