1 files changed, 119 insertions, 0 deletions
diff --git a/system-build/functions/losetup.sh b/system-build/functions/losetup.sh
new file mode 100755
index 0000000..0346ff6
--- /dev/null
+++ b/system-build/functions/losetup.sh
@@ -0,0 +1,119 @@
+#!/bin/sh
+
+## live-build(7) - System Build Scripts
+## Copyright (C) 2006-2015 Daniel Baumann <mail@daniel-baumann.ch>
+##
+## This program comes with ABSOLUTELY NO WARRANTY; for details see COPYING.
+## This is free software, and you are welcome to redistribute it
+## under certain conditions; see COPYING for details.
+
+Lodetach ()
+{
+	DEVICE="${1}"
+	ATTEMPT="${2:-1}"
+
+	if [ "${ATTEMPT}" -gt 3 ]
+	then
+		Echo_error "Failed to detach loop device '${DEVICE}'."
+		exit 1
+	fi
+
+	# Changes to block devices result in uevents which trigger rules which in
+	# turn access the loop device (ex. udisks-part-id, blkid) which can cause
+	# a race condition. We call 'udevadm settle' to help avoid this.
+	if [ -x "$(which udevadm 2>/dev/null)" ]
+	then
+		udevadm settle
+	fi
+
+	# Loop back devices aren't the most reliable when it comes to writes.
+	# We sleep and sync for good measure - better than build failure.
+	sync
+	sleep 1
+
+	${LB_LOSETUP} -d "${DEVICE}" || Lodetach "${DEVICE}" "$(expr ${ATTEMPT} + 1)"
+}
+
+Losetup ()
+{
+	DEVICE="${1}"
+	FILE="${2}"
+	PARTITION="${3:-1}"
+
+	${LB_LOSETUP} --read-only "${DEVICE}" "${FILE}"
+	FDISK_OUT="$(${LB_FDISK} -l -u ${DEVICE} 2>&1)"
+	Lodetach "${DEVICE}"
+
+	LOOPDEVICE="$(echo ${DEVICE}p${PARTITION})"
+
+	if [ "${PARTITION}" = "0" ]
+	then
+		Echo_message "Mounting %s with offset 0" "${DEVICE}"
+
+		${LB_LOSETUP} "${DEVICE}" "${FILE}"
+	else
+		SECTORS="$(echo "$FDISK_OUT" | sed -ne "s|^$LOOPDEVICE[ *]*\([0-9]*\).*|\1|p")"
+		OFFSET="$(expr ${SECTORS} '*' 512)"
+
+		Echo_message "Mounting %s with offset %s" "${DEVICE}" "${OFFSET}"
+
+		${LB_LOSETUP} -o "${OFFSET}" "${DEVICE}" "${FILE}"
+	fi
+}
+
+# adapted from lib/ext2fs/mkjournal.c, default block size is 4096 bytes (/etc/mke2fs.conf).
+ext2fs_default_journal_size()
+{
+	SIZE="$1"
+	if [ "${SIZE}" -lt "8" ]; then # 2048*4096
+		echo 0
+	elif [ "${SIZE}" -lt "128" ]; then # 32768*4096
+		echo 4
+	elif [ "${SIZE}" -lt "1024" ]; then # 256*1024*4096
+		echo 16
+	elif [ "${SIZE}" -lt "2048" ]; then # 512*1024*4096
+		echo 32
+	elif [ "${SIZE}" -lt "4096" ]; then # 1024*1024*4096
+		echo 64
+	else
+		echo 128
+	fi
+}
+
+Calculate_partition_size_without_journal ()
+{
+	WITHOUT_JOURNAL_ORIGINAL_SIZE="${1}"
+	WITHOUT_JOURNAL_FILESYSTEM="${2}"
+
+	case "${WITHOUT_JOURNAL_FILESYSTEM}" in
+		ext2|ext3|ext4)
+			PERCENT="6"
+			;;
+		*)
+			PERCENT="3"
+			;;
+	esac
+
+	echo $(expr ${WITHOUT_JOURNAL_ORIGINAL_SIZE} + ${WITHOUT_JOURNAL_ORIGINAL_SIZE} \* ${PERCENT} / 100 + 1)
+}
+
+Calculate_partition_size ()
+{
+	ORIGINAL_SIZE="${1}"
+	FILESYSTEM="${2}"
+
+	case "${FILESYSTEM}" in
+		ext3|ext4)
+			NON_JOURNAL_SIZE=$(Calculate_partition_size_without_journal ${ORIGINAL_SIZE} ${FILESYSTEM})
+			PROJECTED_JOURNAL_SIZE=$(ext2fs_default_journal_size ${NON_JOURNAL_SIZE})
+			PROJECTED_PARTITION_SIZE=$(expr ${ORIGINAL_SIZE} + ${PROJECTED_JOURNAL_SIZE})
+			PRE_FINAL_PARTITION_SIZE=$(Calculate_partition_size_without_journal ${PROJECTED_PARTITION_SIZE} ${FILESYSTEM})
+			JOURNAL_SIZE=$(ext2fs_default_journal_size ${PRE_FINAL_PARTITION_SIZE})
+
+			expr $(Calculate_partition_size_without_journal ${ORIGINAL_SIZE} ${FILESYSTEM}) + ${JOURNAL_SIZE}
+			;;
+		*)
+			Calculate_partition_size_without_journal ${ORIGINAL_SIZE} ${FILESYSTEM}
+			;;
+	esac
+}