1 files changed, 93 insertions, 0 deletions
diff --git a/romtal-sistem-dondurma/usr/sbin/overlayroot-chroot b/romtal-sistem-dondurma/usr/sbin/overlayroot-chroot
new file mode 100755
index 0000000..6c37962
--- /dev/null
+++ b/romtal-sistem-dondurma/usr/sbin/overlayroot-chroot
@@ -0,0 +1,93 @@
+#!/bin/sh
+#
+#    overlayroot-chroot - chroot wrapper script for overlayroot
+#    Copyright (C) 2012 Dustin Kirkland <[email protected]>
+#
+#    Authors: Dustin Kirkland <[email protected]>
+#
+#    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, version 3 of the License.
+#
+#    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 <http://www.gnu.org/licenses/>.
+
+set -e
+set -f # disable path expansion
+REMOUNTS=""
+
+error() {
+	printf "ERROR: $@\n" 1>&2
+}
+fail() { [ $# -eq 0 ] || error "$@"; exit 1; }
+
+info() {
+	printf "INFO: $@\n" 1>&2
+}
+
+get_lowerdir() {
+	local overlay=""
+	overlay=$(awk \
+		'$1 == "overlayroot" && $2 == "/" { print $0 }' /proc/mounts)
+	if [ -n "${overlay}" ]; then
+		lowerdir=${overlay##*lowerdir=}
+		lowerdir=${lowerdir%%,*}
+		if mountpoint "${lowerdir}" >/dev/null; then
+			_RET="${lowerdir}"
+		else
+			fail "Unable to find the overlayroot lowerdir"
+		fi
+	else
+		fail "Unable to find an overlayroot filesystem"
+	fi
+}
+
+clean_exit() {
+	local mounts="$1" rc=0 d="" lowerdir="" mp=""
+	for d in ${mounts}; do
+		if mountpoint ${d} >/dev/null; then
+			umount ${d} || rc=1
+		fi
+	done
+	for mp in $REMOUNTS; do
+		mount -o remount,ro "${mp}" ||
+			error "Note that [${mp}] is still mounted read/write"
+	done
+	[ "$2" = "return" ] && return ${rc} || exit ${rc}
+}
+
+# Try to find the overlayroot filesystem
+get_lowerdir
+lowerdir=${_RET}
+
+recurse_mps=$(awk '$1 ~ /^\/dev\// && $2 ~ starts { print $2 }' \
+	starts="^$lowerdir/" /proc/mounts)
+
+mounts=
+for d in proc run sys; do
+	if ! mountpoint "${lowerdir}/${d}" >/dev/null; then
+		mount -o bind "/${d}" "${lowerdir}/${d}" || fail "Unable to bind /${d}"
+		mounts="$mounts $lowerdir/$d"
+		trap "clean_exit \"${mounts}\" || true" EXIT HUP INT QUIT TERM
+	fi
+done
+
+# Remount with read/write
+for mp in "$lowerdir" $recurse_mps; do
+	mount -o remount,rw "${mp}" &&
+		REMOUNTS="$mp $REMOUNTS" ||
+		fail "Unable to remount [$mp] writable"
+done
+info "Chrooting into [${lowerdir}]"
+chroot ${lowerdir} "$@"
+
+# Clean up mounts on exit
+clean_exit "${mounts}" "return"
+trap "" EXIT HUP INT QUIT TERM
+
+# vi: ts=4 noexpandtab