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-rwxr-xr-xsrc/dpkg-maintscript-helper.sh667
1 files changed, 667 insertions, 0 deletions
diff --git a/src/dpkg-maintscript-helper.sh b/src/dpkg-maintscript-helper.sh
new file mode 100755
index 0000000..d799aa8
--- /dev/null
+++ b/src/dpkg-maintscript-helper.sh
@@ -0,0 +1,667 @@
+#!/bin/sh
+#
+# Copyright © 2007, 2011-2015 Guillem Jover <guillem@debian.org>
+# Copyright © 2010 Raphaël Hertzog <hertzog@debian.org>
+# Copyright © 2008 Joey Hess <joeyh@debian.org>
+# Copyright © 2005 Scott James Remnant (original implementation on www.dpkg.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, see <https://www.gnu.org/licenses/>.
+
+# The conffile related functions are inspired by
+# https://wiki.debian.org/DpkgConffileHandling
+
+# This script is documented in dpkg-maintscript-helper(1)
+
+##
+## Functions to remove an obsolete conffile during upgrade
+##
+rm_conffile() {
+ local CONFFILE="$1"
+ local LASTVERSION="$2"
+ local PACKAGE="$3"
+
+ if [ "$LASTVERSION" = "--" ]; then
+ LASTVERSION=""
+ PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
+ fi
+ if [ "$PACKAGE" = "--" -o -z "$PACKAGE" ]; then
+ PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
+ fi
+ # Skip remaining parameters up to --
+ while [ "$1" != "--" -a $# -gt 0 ]; do
+ shift
+ done
+ [ $# -gt 0 ] || badusage "missing arguments after --"
+ shift
+
+ [ -n "$PACKAGE" ] || error "couldn't identify the package"
+ [ -n "$1" ] || error "maintainer script parameters are missing"
+ [ -n "$DPKG_MAINTSCRIPT_NAME" ] || \
+ error "environment variable DPKG_MAINTSCRIPT_NAME is required"
+ [ -n "$DPKG_MAINTSCRIPT_PACKAGE" ] || \
+ error "environment variable DPKG_MAINTSCRIPT_PACKAGE is required"
+ [ "${CONFFILE}" != "${CONFFILE#/}" ] || \
+ error "conffile '$CONFFILE' is not an absolute path"
+ validate_optional_version "$LASTVERSION"
+
+ debug "Executing $0 rm_conffile in $DPKG_MAINTSCRIPT_NAME" \
+ "of $DPKG_MAINTSCRIPT_PACKAGE"
+ debug "CONFFILE=$CONFFILE PACKAGE=$PACKAGE" \
+ "LASTVERSION=$LASTVERSION ACTION=$1 PARAM=$2"
+ case "$DPKG_MAINTSCRIPT_NAME" in
+ preinst)
+ if [ "$1" = "install" -o "$1" = "upgrade" ] && [ -n "$2" ] &&
+ dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
+ prepare_rm_conffile "$CONFFILE" "$PACKAGE"
+ fi
+ ;;
+ postinst)
+ if [ "$1" = "configure" ] && [ -n "$2" ] &&
+ dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
+ finish_rm_conffile "$CONFFILE"
+ fi
+ ;;
+ postrm)
+ if [ "$1" = "purge" ]; then
+ rm -f "$DPKG_ROOT$CONFFILE.dpkg-bak" \
+ "$DPKG_ROOT$CONFFILE.dpkg-remove" \
+ "$DPKG_ROOT$CONFFILE.dpkg-backup"
+ fi
+ if [ "$1" = "abort-install" -o "$1" = "abort-upgrade" ] &&
+ [ -n "$2" ] &&
+ dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
+ abort_rm_conffile "$CONFFILE" "$PACKAGE"
+ fi
+ ;;
+ *)
+ debug "$0 rm_conffile not required in $DPKG_MAINTSCRIPT_NAME"
+ ;;
+ esac
+}
+
+prepare_rm_conffile() {
+ local CONFFILE="$1"
+ local PACKAGE="$2"
+
+ [ -e "$DPKG_ROOT$CONFFILE" ] || return 0
+ ensure_package_owns_file "$PACKAGE" "$CONFFILE" || return 0
+
+ local md5sum old_md5sum
+ md5sum="$(md5sum "$DPKG_ROOT$CONFFILE" | sed -e 's/ .*//')"
+ old_md5sum="$(dpkg-query -W -f='${Conffiles}' "$PACKAGE" | \
+ sed -n -e "\\'^ $CONFFILE ' { s/ obsolete$//; s/.* //; p }")"
+ if [ "$md5sum" != "$old_md5sum" ]; then
+ mv -f "$DPKG_ROOT$CONFFILE" "$DPKG_ROOT$CONFFILE.dpkg-backup"
+ else
+ mv -f "$DPKG_ROOT$CONFFILE" "$DPKG_ROOT$CONFFILE.dpkg-remove"
+ fi
+}
+
+finish_rm_conffile() {
+ local CONFFILE="$1"
+
+ if [ -e "$DPKG_ROOT$CONFFILE.dpkg-backup" ]; then
+ echo "Obsolete conffile $DPKG_ROOT$CONFFILE has been modified by you."
+ echo "Saving as $DPKG_ROOT$CONFFILE.dpkg-bak ..."
+ mv -f "$DPKG_ROOT$CONFFILE.dpkg-backup" "$DPKG_ROOT$CONFFILE.dpkg-bak"
+ fi
+ if [ -e "$DPKG_ROOT$CONFFILE.dpkg-remove" ]; then
+ echo "Removing obsolete conffile $DPKG_ROOT$CONFFILE ..."
+ rm -f "$DPKG_ROOT$CONFFILE.dpkg-remove"
+ fi
+}
+
+abort_rm_conffile() {
+ local CONFFILE="$1"
+ local PACKAGE="$2"
+
+ ensure_package_owns_file "$PACKAGE" "$CONFFILE" || return 0
+
+ if [ -e "$DPKG_ROOT$CONFFILE.dpkg-remove" ]; then
+ echo "Reinstalling $DPKG_ROOT$CONFFILE that was moved away"
+ mv "$DPKG_ROOT$CONFFILE.dpkg-remove" "$DPKG_ROOT$CONFFILE"
+ fi
+ if [ -e "$DPKG_ROOT$CONFFILE.dpkg-backup" ]; then
+ echo "Reinstalling $DPKG_ROOT$CONFFILE that was backed-up"
+ mv "$DPKG_ROOT$CONFFILE.dpkg-backup" "$DPKG_ROOT$CONFFILE"
+ fi
+}
+
+##
+## Functions to rename a conffile during upgrade
+##
+mv_conffile() {
+ local OLDCONFFILE="$1"
+ local NEWCONFFILE="$2"
+ local LASTVERSION="$3"
+ local PACKAGE="$4"
+
+ if [ "$LASTVERSION" = "--" ]; then
+ LASTVERSION=""
+ PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
+ fi
+ if [ "$PACKAGE" = "--" -o -z "$PACKAGE" ]; then
+ PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
+ fi
+ # Skip remaining parameters up to --
+ while [ "$1" != "--" -a $# -gt 0 ]; do
+ shift
+ done
+ [ $# -gt 0 ] || badusage "missing arguments after --"
+ shift
+
+ [ -n "$PACKAGE" ] || error "couldn't identify the package"
+ [ -n "$1" ] || error "maintainer script parameters are missing"
+ [ -n "$DPKG_MAINTSCRIPT_NAME" ] || \
+ error "environment variable DPKG_MAINTSCRIPT_NAME is required"
+ [ -n "$DPKG_MAINTSCRIPT_PACKAGE" ] || \
+ error "environment variable DPKG_MAINTSCRIPT_PACKAGE is required"
+ [ "${OLDCONFFILE}" != "${OLDCONFFILE#/}" ] || \
+ error "old-conffile '$OLDCONFFILE' is not an absolute path"
+ [ "${NEWCONFFILE}" != "${NEWCONFFILE#/}" ] || \
+ error "new-conffile '$NEWCONFFILE' is not an absolute path"
+ validate_optional_version "$LASTVERSION"
+
+ debug "Executing $0 mv_conffile in $DPKG_MAINTSCRIPT_NAME" \
+ "of $DPKG_MAINTSCRIPT_PACKAGE"
+ debug "CONFFILE=$OLDCONFFILE -> $NEWCONFFILE PACKAGE=$PACKAGE" \
+ "LASTVERSION=$LASTVERSION ACTION=$1 PARAM=$2"
+ case "$DPKG_MAINTSCRIPT_NAME" in
+ preinst)
+ if [ "$1" = "install" -o "$1" = "upgrade" ] && [ -n "$2" ] &&
+ dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
+ prepare_mv_conffile "$OLDCONFFILE" "$PACKAGE"
+ fi
+ ;;
+ postinst)
+ if [ "$1" = "configure" ] && [ -n "$2" ] &&
+ dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
+ finish_mv_conffile "$OLDCONFFILE" "$NEWCONFFILE" "$PACKAGE"
+ fi
+ ;;
+ postrm)
+ if [ "$1" = "abort-install" -o "$1" = "abort-upgrade" ] &&
+ [ -n "$2" ] &&
+ dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
+ abort_mv_conffile "$OLDCONFFILE" "$PACKAGE"
+ fi
+ ;;
+ *)
+ debug "$0 mv_conffile not required in $DPKG_MAINTSCRIPT_NAME"
+ ;;
+ esac
+}
+
+prepare_mv_conffile() {
+ local CONFFILE="$1"
+ local PACKAGE="$2"
+
+ [ -e "$DPKG_ROOT$CONFFILE" ] || return 0
+
+ ensure_package_owns_file "$PACKAGE" "$CONFFILE" || return 0
+
+ local md5sum old_md5sum
+ md5sum="$(md5sum "$DPKG_ROOT$CONFFILE" | sed -e 's/ .*//')"
+ old_md5sum="$(dpkg-query -W -f='${Conffiles}' "$PACKAGE" | \
+ sed -n -e "\\'^ $CONFFILE ' { s/ obsolete$//; s/.* //; p }")"
+ if [ "$md5sum" = "$old_md5sum" ]; then
+ mv -f "$DPKG_ROOT$CONFFILE" "$DPKG_ROOT$CONFFILE.dpkg-remove"
+ fi
+}
+
+finish_mv_conffile() {
+ local OLDCONFFILE="$1"
+ local NEWCONFFILE="$2"
+ local PACKAGE="$3"
+
+ rm -f "$DPKG_ROOT$OLDCONFFILE.dpkg-remove"
+
+ [ -e "$DPKG_ROOT$OLDCONFFILE" ] || return 0
+ ensure_package_owns_file "$PACKAGE" "$OLDCONFFILE" || return 0
+
+ echo "Preserving user changes to $DPKG_ROOT$NEWCONFFILE (renamed from $DPKG_ROOT$OLDCONFFILE)..."
+ if [ -e "$DPKG_ROOT$NEWCONFFILE" ]; then
+ mv -f "$DPKG_ROOT$NEWCONFFILE" "$DPKG_ROOT$NEWCONFFILE.dpkg-new"
+ fi
+ mv -f "$DPKG_ROOT$OLDCONFFILE" "$DPKG_ROOT$NEWCONFFILE"
+}
+
+abort_mv_conffile() {
+ local CONFFILE="$1"
+ local PACKAGE="$2"
+
+ ensure_package_owns_file "$PACKAGE" "$CONFFILE" || return 0
+
+ if [ -e "$DPKG_ROOT$CONFFILE.dpkg-remove" ]; then
+ echo "Reinstalling $DPKG_ROOT$CONFFILE that was moved away"
+ mv "$DPKG_ROOT$CONFFILE.dpkg-remove" "$DPKG_ROOT$CONFFILE"
+ fi
+}
+
+##
+## Functions to replace a symlink with a directory
+##
+symlink_to_dir() {
+ local SYMLINK="$1"
+ local SYMLINK_TARGET="$2"
+ local LASTVERSION="$3"
+ local PACKAGE="$4"
+
+ if [ "$LASTVERSION" = "--" ]; then
+ LASTVERSION=""
+ PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
+ fi
+ if [ "$PACKAGE" = "--" -o -z "$PACKAGE" ]; then
+ PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
+ fi
+
+ # Skip remaining parameters up to --
+ while [ "$1" != "--" -a $# -gt 0 ]; do
+ shift
+ done
+ [ $# -gt 0 ] || badusage "missing arguments after --"
+ shift
+
+ [ -n "$DPKG_MAINTSCRIPT_NAME" ] || \
+ error "environment variable DPKG_MAINTSCRIPT_NAME is required"
+ [ -n "$DPKG_MAINTSCRIPT_PACKAGE" ] || \
+ error "environment variable DPKG_MAINTSCRIPT_PACKAGE is required"
+ [ -n "$PACKAGE" ] || error "cannot identify the package"
+ [ -n "$SYMLINK" ] || error "symlink parameter is missing"
+ [ "${SYMLINK#/}" = "$SYMLINK" ] && \
+ error "symlink pathname is not an absolute path"
+ [ "${SYMLINK%/}" = "$SYMLINK" ] || \
+ error "symlink pathname ends with a slash"
+ [ -n "$SYMLINK_TARGET" ] || error "original symlink target is missing"
+ [ -n "$1" ] || error "maintainer script parameters are missing"
+ validate_optional_version "$LASTVERSION"
+
+ debug "Executing $0 symlink_to_dir in $DPKG_MAINTSCRIPT_NAME" \
+ "of $DPKG_MAINTSCRIPT_PACKAGE"
+ debug "SYMLINK=$SYMLINK -> $SYMLINK_TARGET PACKAGE=$PACKAGE" \
+ "LASTVERSION=$LASTVERSION ACTION=$1 PARAM=$2"
+
+ case "$DPKG_MAINTSCRIPT_NAME" in
+ preinst)
+ if [ "$1" = "install" -o "$1" = "upgrade" ] &&
+ [ -n "$2" ] && [ -h "$DPKG_ROOT$SYMLINK" ] &&
+ symlink_match "$SYMLINK" "$SYMLINK_TARGET" &&
+ dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
+ mv -f "$DPKG_ROOT$SYMLINK" "$DPKG_ROOT${SYMLINK}.dpkg-backup"
+ fi
+ ;;
+ postinst)
+ # We cannot bail depending on the version, as here we only
+ # know what was the last configured version, and we might
+ # have been unpacked, then upgraded with an unpack and thus
+ # never been configured before.
+ if [ "$1" = "configure" ] &&
+ [ -h "$DPKG_ROOT${SYMLINK}.dpkg-backup" ] &&
+ symlink_match "${SYMLINK}.dpkg-backup" "$SYMLINK_TARGET"
+ then
+ rm -f "$DPKG_ROOT${SYMLINK}.dpkg-backup"
+ fi
+ ;;
+ postrm)
+ if [ "$1" = "purge" ] && [ -h "$DPKG_ROOT${SYMLINK}.dpkg-backup" ]; then
+ rm -f "$DPKG_ROOT${SYMLINK}.dpkg-backup"
+ fi
+ if [ "$1" = "abort-install" -o "$1" = "abort-upgrade" ] &&
+ [ -n "$2" ] &&
+ [ ! -e "$DPKG_ROOT$SYMLINK" ] &&
+ [ -h "$DPKG_ROOT${SYMLINK}.dpkg-backup" ] &&
+ symlink_match "${SYMLINK}.dpkg-backup" "$SYMLINK_TARGET" &&
+ dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
+ echo "Restoring backup of $DPKG_ROOT$SYMLINK ..."
+ mv "$DPKG_ROOT${SYMLINK}.dpkg-backup" "$DPKG_ROOT$SYMLINK"
+ fi
+ ;;
+ *)
+ debug "$0 symlink_to_dir not required in $DPKG_MAINTSCRIPT_NAME"
+ ;;
+ esac
+}
+
+##
+## Functions to replace a directory with a symlink
+##
+dir_to_symlink() {
+ local PATHNAME="${1%/}"
+ local SYMLINK_TARGET="$2"
+ local LASTVERSION="$3"
+ local PACKAGE="$4"
+
+ if [ "$LASTVERSION" = "--" ]; then
+ LASTVERSION=""
+ PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
+ fi
+ if [ "$PACKAGE" = "--" -o -z "$PACKAGE" ]; then
+ PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
+ fi
+
+ # Skip remaining parameters up to --
+ while [ "$1" != "--" -a $# -gt 0 ]; do
+ shift
+ done
+ [ $# -gt 0 ] || badusage "missing arguments after --"
+ shift
+
+ [ -n "$DPKG_MAINTSCRIPT_NAME" ] || \
+ error "environment variable DPKG_MAINTSCRIPT_NAME is required"
+ [ -n "$DPKG_MAINTSCRIPT_PACKAGE" ] || \
+ error "environment variable DPKG_MAINTSCRIPT_PACKAGE is required"
+ [ -n "$PACKAGE" ] || error "cannot identify the package"
+ [ -n "$PATHNAME" ] || error "directory parameter is missing"
+ [ "${PATHNAME#/}" = "$PATHNAME" ] && \
+ error "directory parameter is not an absolute path"
+ [ -n "$SYMLINK_TARGET" ] || error "new symlink target is missing"
+ [ -n "$1" ] || error "maintainer script parameters are missing"
+ validate_optional_version "$LASTVERSION"
+
+ debug "Executing $0 dir_to_symlink in $DPKG_MAINTSCRIPT_NAME" \
+ "of $DPKG_MAINTSCRIPT_PACKAGE"
+ debug "PATHNAME=$PATHNAME SYMLINK_TARGET=$SYMLINK_TARGET" \
+ "PACKAGE=$PACKAGE LASTVERSION=$LASTVERSION ACTION=$1 PARAM=$2"
+
+ case "$DPKG_MAINTSCRIPT_NAME" in
+ preinst)
+ if [ "$1" = "install" -o "$1" = "upgrade" ] &&
+ [ -n "$2" ] &&
+ [ ! -h "$DPKG_ROOT$PATHNAME" ] &&
+ [ -d "$DPKG_ROOT$PATHNAME" ] &&
+ dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
+ prepare_dir_to_symlink "$PACKAGE" "$PATHNAME"
+ fi
+ ;;
+ postinst)
+ # We cannot bail depending on the version, as here we only
+ # know what was the last configured version, and we might
+ # have been unpacked, then upgraded with an unpack and thus
+ # never been configured before.
+ if [ "$1" = "configure" ] &&
+ [ -d "$DPKG_ROOT${PATHNAME}.dpkg-backup" ] &&
+ [ ! -h "$DPKG_ROOT$PATHNAME" ] &&
+ [ -d "$DPKG_ROOT$PATHNAME" ] &&
+ [ -f "$DPKG_ROOT$PATHNAME/.dpkg-staging-dir" ]; then
+ finish_dir_to_symlink "$PATHNAME" "$SYMLINK_TARGET"
+ fi
+ ;;
+ postrm)
+ if [ "$1" = "purge" ] &&
+ [ -d "$DPKG_ROOT${PATHNAME}.dpkg-backup" ]; then
+ rm -rf "$DPKG_ROOT${PATHNAME}.dpkg-backup"
+ fi
+ if [ "$1" = "abort-install" -o "$1" = "abort-upgrade" ] &&
+ [ -n "$2" ] &&
+ [ -d "$DPKG_ROOT${PATHNAME}.dpkg-backup" ] &&
+ [ \( ! -h "$DPKG_ROOT$PATHNAME" -a \
+ -d "$DPKG_ROOT$PATHNAME" -a \
+ -f "$DPKG_ROOT$PATHNAME/.dpkg-staging-dir" \) -o \
+ \( -h "$DPKG_ROOT$PATHNAME" -a \
+ \( "$(readlink "$DPKG_ROOT$PATHNAME")" = "$SYMLINK_TARGET" -o \
+ "$(dpkg-realpath "$PATHNAME")" = "$SYMLINK_TARGET" \) \) ] &&
+ dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
+ abort_dir_to_symlink "$PATHNAME"
+ fi
+ ;;
+ *)
+ debug "$0 dir_to_symlink not required in $DPKG_MAINTSCRIPT_NAME"
+ ;;
+ esac
+}
+
+prepare_dir_to_symlink()
+{
+ local PACKAGE="$1"
+ local PATHNAME="$2"
+
+ local LINE
+ # If there are conffiles we should not perform the switch.
+ dpkg-query -W -f='${Conffiles}\n' "$PACKAGE" | while read -r LINE; do
+ case "$LINE" in
+ "$PATHNAME"/*)
+ error "directory '$PATHNAME' contains conffiles," \
+ "cannot switch to symlink"
+ ;;
+ esac
+ done
+
+ # If there are locally created files or files owned by another package
+ # we should not perform the switch.
+ export DPKG_MAINTSCRIPT_HELPER_INTERNAL_API="$version"
+ find "$DPKG_ROOT$PATHNAME" -print0 | \
+ xargs -0 -n1 "$0" _internal_pkg_must_own_file "$PACKAGE" || \
+ error "directory '$PATHNAME' contains files not owned by" \
+ "package $PACKAGE, cannot switch to symlink"
+ unset DPKG_MAINTSCRIPT_HELPER_INTERNAL_API
+
+ # At this point, we know that the directory either contains no files,
+ # or only non-conffiles owned by the package.
+ #
+ # To do the switch we cannot simply replace it with the final symlink
+ # just yet, because dpkg needs to remove any file present in the old
+ # package that have disappeared in the new one, and we do not want to
+ # lose files resolving to the same pathname in the symlink target.
+ #
+ # We cannot replace the directory with a staging symlink either,
+ # because dpkg will update symlinks to their new target.
+ #
+ # So we need to create a staging directory, to avoid removing files
+ # from other packages, and to trap any new files in the directory
+ # to move them to their correct place later on.
+ mv -f "$DPKG_ROOT$PATHNAME" "$DPKG_ROOT${PATHNAME}.dpkg-backup"
+ mkdir "$DPKG_ROOT$PATHNAME"
+
+ # Mark it as a staging directory, so that we can track things.
+ touch "$DPKG_ROOT$PATHNAME/.dpkg-staging-dir"
+}
+
+finish_dir_to_symlink()
+{
+ local PATHNAME="$1"
+ local SYMLINK_TARGET="$2"
+
+ # Move the contents of the staging directory to the symlink target,
+ # as those are all new files installed between this package being
+ # unpacked and configured.
+ local ABS_SYMLINK_TARGET
+ if [ "${SYMLINK_TARGET#/}" = "$SYMLINK_TARGET" ]; then
+ ABS_SYMLINK_TARGET="$(dirname "$PATHNAME")/$SYMLINK_TARGET"
+ else
+ ABS_SYMLINK_TARGET="$SYMLINK_TARGET"
+ fi
+ rm "$DPKG_ROOT$PATHNAME/.dpkg-staging-dir"
+ find "$DPKG_ROOT$PATHNAME" -mindepth 1 -maxdepth 1 -print0 | \
+ xargs -0 -I% mv -f "%" "$DPKG_ROOT$ABS_SYMLINK_TARGET/"
+
+ # Remove the staging directory.
+ rmdir "$DPKG_ROOT$PATHNAME"
+
+ # Do the actual switch.
+ ln -s "$SYMLINK_TARGET" "$DPKG_ROOT$PATHNAME"
+
+ # We are left behind the old files owned by this package in the backup
+ # directory, just remove it.
+ rm -rf "$DPKG_ROOT${PATHNAME}.dpkg-backup"
+}
+
+abort_dir_to_symlink()
+{
+ local PATHNAME="$1"
+
+ echo "Restoring backup of $DPKG_ROOT$PATHNAME ..."
+ if [ -h "$DPKG_ROOT$PATHNAME" ]; then
+ rm -f "$DPKG_ROOT$PATHNAME"
+ else
+ # The staging directory must be empty, as no other package
+ # should have been unpacked in between.
+ rm -f "$DPKG_ROOT$PATHNAME/.dpkg-staging-dir"
+ rmdir "$DPKG_ROOT$PATHNAME"
+ fi
+
+ mv "$DPKG_ROOT${PATHNAME}.dpkg-backup" "$DPKG_ROOT$PATHNAME"
+}
+
+# Common functions
+validate_optional_version() {
+ local VERSION="$1"
+
+ if [ -z "$VERSION" ]; then
+ return
+ fi
+
+ if ! VERSIONCHECK=$(dpkg --validate-version -- "$VERSION" 2>&1); then
+ error "$VERSIONCHECK"
+ fi
+}
+
+ensure_package_owns_file() {
+ local PACKAGE="$1"
+ local FILE="$2"
+
+ if ! dpkg-query -L "$PACKAGE" | grep -F -q -x "$FILE"; then
+ debug "File '$FILE' not owned by package " \
+ "'$PACKAGE', skipping $command"
+ return 1
+ fi
+ return 0
+}
+
+internal_pkg_must_own_file()
+{
+ local PACKAGE="$1"
+ local FILE="${2##"$DPKG_ROOT"}"
+
+ if [ "$DPKG_MAINTSCRIPT_HELPER_INTERNAL_API" != "$version" ]; then
+ error "internal API used by external command"
+ fi
+
+ if ! ensure_package_owns_file "$PACKAGE" "$FILE"; then
+ error "file '$FILE' not owned by package '$PACKAGE'"
+ fi
+ return 0
+}
+
+symlink_match()
+{
+ local SYMLINK="$1"
+ local SYMLINK_TARGET="$2"
+
+ [ "$(readlink "$DPKG_ROOT$SYMLINK")" = "$SYMLINK_TARGET" ] || \
+ [ "$(dpkg-realpath "$SYMLINK")" = "$SYMLINK_TARGET" ]
+}
+
+usage() {
+ cat <<END
+Usage: $PROGNAME <command> <parameter>... -- <maintainer-script-parameter>...
+
+Commands:
+ supports <command>
+ Returns 0 (success) if the given command is supported, 1 otherwise.
+ rm_conffile <conffile> [<last-version> [<package>]]
+ Remove obsolete conffile. Must be called in preinst, postinst and
+ postrm.
+ mv_conffile <old-conf> <new-conf> [<last-version> [<package>]]
+ Rename a conffile. Must be called in preinst, postinst and postrm.
+ symlink_to_dir <pathname> <old-symlink-target> [<last-version> [<package>]]
+ Replace a symlink with a directory. Must be called in preinst,
+ postinst and postrm.
+ dir_to_symlink <pathname> <new-symlink-target> [<last-version> [<package>]]
+ Replace a directory with a symlink. Must be called in preinst,
+ postinst and postrm.
+ help
+ -?, --help
+ Show this help message.
+ --version
+ Show the version.
+END
+}
+
+# Main code
+set -e
+
+PROGNAME=$(basename "$0")
+version="unknown"
+DPKG_ROOT=${DPKG_ROOT:+$(realpath "$DPKG_ROOT")}
+# Remove default root dir.
+if [ "$DPKG_ROOT" = "/" ]; then
+ DPKG_ROOT=""
+fi
+export DPKG_ROOT
+
+PKGDATADIR_DEFAULT=src
+PKGDATADIR="${DPKG_DATADIR:-$PKGDATADIR_DEFAULT}"
+
+# shellcheck source=src/sh/dpkg-error.sh
+. "$PKGDATADIR/sh/dpkg-error.sh"
+
+setup_colors
+
+command="$1"
+[ $# -gt 0 ] || badusage "missing command"
+shift
+
+case "$command" in
+supports)
+ case "$1" in
+ rm_conffile|mv_conffile|symlink_to_dir|dir_to_symlink)
+ code=0
+ ;;
+ *)
+ code=1
+ ;;
+ esac
+ if [ -z "$DPKG_MAINTSCRIPT_NAME" ]; then
+ warning "environment variable DPKG_MAINTSCRIPT_NAME missing"
+ code=1
+ fi
+ if [ -z "$DPKG_MAINTSCRIPT_PACKAGE" ]; then
+ warning "environment variable DPKG_MAINTSCRIPT_PACKAGE missing"
+ code=1
+ fi
+ exit $code
+ ;;
+rm_conffile)
+ rm_conffile "$@"
+ ;;
+mv_conffile)
+ mv_conffile "$@"
+ ;;
+symlink_to_dir)
+ symlink_to_dir "$@"
+ ;;
+dir_to_symlink)
+ dir_to_symlink "$@"
+ ;;
+_internal_pkg_must_own_file)
+ # This is an internal command, must not be used outside this program.
+ internal_pkg_must_own_file "$@"
+ ;;
+--help|help|-?)
+ usage
+ ;;
+--version)
+ cat <<END
+Debian $PROGNAME version $version.
+
+This is free software; see the GNU General Public License version 2 or
+later for copying conditions. There is NO warranty.
+END
+ ;;
+*)
+ badusage "command $command is unknown
+Hint: upgrading dpkg to a newer version might help."
+esac
+
+exit 0