#!/bin/sh

# make sure we exit on error
set -e

# Sanitise environment
while read -r env ; do
    case "$env" in
	'') continue ;;
	OPTIND) ;; # Dash croaks when unsetting OPTIND. See #985478
	PATH|PWD|TERM) ;;
	UCF_*) ;;
	*) unset "$env" ;;
    esac
done<<EOF
$(awk 'BEGIN{for(v in ENVIRON) print v}')
EOF

# set the version and revision
progname=$(basename "$0")
pversion='3.0050'
######################################################################
########                                                     #########
########              Utility functions                      #########
########                                                     #########
######################################################################
for libdir in "$(dirname "$0")" /usr/share/ucf ; do
    [ -f "${libdir}/ucf_library.sh" ] && \
	. "${libdir}/ucf_library.sh" && \
	break
done

purge_from_registry () {
    if [ ! -e "$statedir/registry" ]; then
        echo >&2 "$progname: Internal error: $statedir/registry does not exist"
        exit 6
    fi

    if [ "$count" -eq 0 ]; then
        [ "$VERBOSE" ] &&
            echo >&2 "$progname: Association already purged. No changes."
        exit 0
    fi
    old_pkg=$(grep "${real_conf_file_bre}" "$statedir/registry" | \
        awk '{print $1}' )
    if [ "$pkg" != "$old_pkg"  ]; then
        echo >&2 "ucfr: Association belongs to $old_pkg, not $pkg"
        if [ ! "$FORCE" ]; then
            echo >&2 "ucfr: Aborting"
            exit 5
        fi
    fi

    # OK, so we have something to purge.
    for i in $(/usr/bin/seq 6 -1 0); do
	if [ -e "${statedir}/registry.${i}" ]; then
	    if [ "$docmd" = "YES" ]; then
		cp -f "${statedir}/registry.${i}"  "${statedir}/registry.$(($i + 1))"
	    else
		echo cp -f "${statedir}/registry.${i}" "${statedir}/registry.$(($i + 1))"
	    fi
	fi
    done
    if [ "$docmd" = "YES" ]; then
	cp -f "$statedir/registry"  "$statedir/registry.0"
    else
	echo cp -f "$statedir/registry"  "$statedir/registry.0"
    fi
    if [ "$docmd" = "YES" ]; then
	 [ "$VERBOSE" ] &&
	    echo "grep -v ${real_conf_file_bre} $statedir/registry >\\" \
		 "	$statedir/registry.tmp || true"
	grep -v "${real_conf_file_bre}" "$statedir/registry" > \
	    "$statedir/registry.tmp" || true
	if [ "$docmd" = "YES" ]; then
	    mv -f "$statedir/registry.tmp"  "$statedir/registry"
	else
	    echo mv -f "$statedir/registry.tmp"  "$statedir/registry"
	fi
    fi
}

replace_in_registry () {
    if [ ! -e "$statedir/registry" ]; then
        echo >&2 "$progname: Internal error: $statedir/registry does not exist"
        exit 6
    fi
    if [ "$count" -eq 1 ]; then
        old_pkg=$(grep "${real_conf_file_bre}" "$statedir/registry" | \
            awk '{print $1;}' )

        if [ "$pkg" != "$old_pkg" ]; then
            divert_package=$(dpkg-divert --listpackage "$conf_file")
            if [ -n "$divert_package" ]; then
                [ "$VERBOSE" ] &&
                    echo >&2 "$progname: Package $pkg will not take away diverted ${conf_file} from package $divert_package"
                exit 0
            else
                if [ ! "$FORCE" ]; then
                    echo >&2 "$progname: Attempt from package $pkg  to take ${real_conf_file} away from package $old_pkg"
                    echo >&2 "ucfr: Aborting."
                    exit 4
                fi
            fi
        else
            [ "$VERBOSE" ] &&
                echo >&2 "$progname: Association already recorded. No changes."
            exit 0
        fi
    fi

    for i in $(/usr/bin/seq 6 -1 0); do
	if [ -e "${statedir}/registry.${i}" ]; then
	    if [ "$docmd" = "YES" ]; then
		cp -f "${statedir}/registry.${i}" \
		    "${statedir}/registry.$(($i + 1))"
	    else
		echo cp -f "${statedir}/registry.${i}" \
		    "${statedir}/registry.$(($i + 1))"
	    fi
	fi
    done
    if [ "$docmd" = "YES" ]; then
	cp -f "$statedir/registry"  "$statedir/registry.0"
    else
	echo cp -f "$statedir/registry"  "$statedir/registry.0"
    fi
    if [ "$docmd" = "YES" ]; then
	set +e
	if [ "$VERBOSE" ]; then
	    echo "grep -v \"${real_conf_file_bre}\" \"$statedir/registry\"  \\"
            echo "	$statedir/registry.tmp || true"
	    echo "echo \"$pkg 	 $real_conf_file\" >> \"$statedir/registry.tmp\""
	    echo "mv -f  $statedir/registry.tmp $statedir/registry"
	fi
	grep -v "${real_conf_file_bre}" "$statedir/registry" > \
	    "$statedir/registry.tmp" || true
	echo "$pkg 	 $real_conf_file" >>   "$statedir/registry.tmp"
	mv -f "$statedir/registry.tmp"  "$statedir/registry"
    else
	echo "grep -v \"${real_conf_file_bre}\" \"$statedir/registry\"  \\"
        echo "	$statedir/registry.tmp || true"
	echo "echo \"$pkg 	 $real_conf_file\" >> \"$statedir/registry.tmp\""
	echo "mv -f  $statedir/registry.tmp $statedir/registry"
    fi
}

usageversion () {
        cat >&2 <<END
Debian GNU/Linux $progname $pversion.
           Copyright (C) 2002-2020 Manoj Srivastava.
	   Copyright (C) 2024- Mark Hindley.
This is free software; see the GNU General Public Licence for copying
conditions.  There is NO warranty.

Usage: $progname  [options] package_name path_for_configuration_file
Options:
     -h,     --help          print this message
     -f      --force         Force the association, even if another package
                             used to own the configuration file.
     -d [n], --debug    [n]  Set the Debug level to N
     -n,     --no-action     Dry run. No action is actually taken.
     -v,     --verbose       Make the script verbose
     -p,     --purge         Remove any reference to the package/file association
                             from the records
             --state-dir bar Set the state directory to bar instead of the
                             default '/var/lib/ucf'. Used mostly for testing.
END

}

######################################################################
########                                                     #########
########              Command line args                      #########
########                                                     #########
######################################################################
#
# Long term variables#
#
docmd='YES'
# action='withecho'
action=
# Unused
# DEBUG=0
VERBOSE=''
statedir='/var/lib/ucf'

handle_file_args() {
    # We have here a configuration file, which can be a symlink, and may
    # contain characters that are unsafe in regular expressions
    pkg=$(vset "$1" "The Package name")
    conf_file=$(vset "$2" "The Configuration file")
    real_conf_file=$(vset "$(readlink -q -m "$conf_file")" "The (real) Configuration file")

    case $real_conf_file in
	/*)
            : echo fine
            ;;
	*)
            echo >&2 "$progname: Need a fully qualified path for the file \"$conf_file\""
            # Don't exit with an error for etch'
            exit 0
    esac

    real_conf_file_bre="[[:space:]]$(escape_bre "$real_conf_file")"'$'
}

handle_opts() {
    # Arguments are from getopt(1) in quoted mode.
    eval set --  "$*"
    while [ $# -gt 0 ] ; do
	case "$1" in
	    -h|--help) usageversion;                        exit 0  ;;
	    -n|--no-action) action='echo'; docmd='NO';      shift   ;;
	    -v|--verbose) VERBOSE=1;                        shift   ;;
	    -f|--force)   FORCE=1;                          shift   ;;
	    --state-dir)  opt_state_dir="$2";               shift 2 ;;
	    -D|-d|--debug|--DEBUG)
		# d has an optional argument. As we are in quoted mode,
		# an empty parameter will be generated if its optional
		# argument is not found.
		#
		# Unused, so ignore silently. The distinction between VERBOSE and
		# DEBUG is a mess and needs reworking.
		#
		# case "$2" in
		# 	"") DEBUG=$(vset 1    "The Debug value")
		# 	*) DEBUG=$(vset "$2" "The Debug value")
		# esac
		shift 2 ;;
            -p|--purge) PURGE=YES;                         shift   ;;
	    --)  shift ; handle_file_args "$@";            break   ;;
	    *) echo >&2 "$progname: Internal error!" ; exit 1 ;;
	esac
    done
    # Need to run as root, or else the
    if test "$(id -u)" != 0; then
	if [ "$docmd" = "YES" ]; then
            echo "$progname: Need to be run as root." >&2
            echo "$progname: Setting up no action mode." >&2
            action='echo';
            docmd='NO';
	fi
    fi

    if [ $# != 2 ]; then
	echo >&2 "$progname: *** ERROR: Need exactly two arguments, got $#";
	echo >&2 ""
	usageversion;
	exit 3 ;
    fi
}

# A separate assignment is essential to ensure getopt(1) error status isn't
# lost.
UCFR_OPTS="$(getopt -a -o hd::D::fnvp -n "$progname" \
	    	     --long help,debug::,DEBUG::,force,no-action,purge,verbose,state-dir: \
            	      -- "$@")"
handle_opts "$UCFR_OPTS"

# Load site defaults and overrides.
if [ -f /etc/ucf.conf ]; then
    . /etc/ucf.conf
fi

# Command line, env variable, config file, or default
if [ "$opt_state_dir" ]; then
    statedir=$(vset "$opt_state_dir" "The State directory")
elif [ "$UCF_STATE_DIR" ]; then
    statedir=$(vset "$UCF_STATE_DIR" "The State directory")
elif [ "$conf_state_dir" ]; then
    statedir=$(vset "$conf_state_dir" "The State directory")
else
    statedir=$(vset '/var/lib/ucf' "The State directory")
fi

# VERBOSE of 0 is supposed to be the same as not setting VERBOSE
if [ "$VERBOSE" = "0" ]; then
    VERBOSE=''
fi

#
if [ -e "$statedir/registry" ] && [ ! -w "$statedir/registry" ]; then
    echo >&2 "$progname: do not have write privilege to the registry data"
    if [ "$docmd" = "YES" ]; then
	exit 1
    fi
fi

# test and see if this file exists in the database
if [ ! -d "$statedir" ]; then
    $action mkdir -p "$statedir"
fi

if [ ! -f "$statedir/registry" ]; then
    $action touch "$statedir/registry"
fi

[ "$VERBOSE" ] &&
    echo >&2 "$progname: The registry exists"

# sanity check
count=$(grep --count "${real_conf_file_bre}" "$statedir/registry") || true

if [ "$count" -ge 2 ]; then
    echo >&2 "$progname: Corrupt registry: Duplicate entries for ${conf_file}"
    grep "${real_conf_file_bre}" "$statedir/registry"
    exit "$count"
fi

if [ "$PURGE" ]; then
    $action purge_from_registry
else
    $action replace_in_registry
fi

exit 0