Initial commit

scripts/functions.sh

@@ -0,0 +1,48 @@
+#!/bin/sh
+
+
+get_magic_word() {
+	dd if=$1 bs=4 count=1 2>/dev/null | od -A n -N 4 -t x1 | tr -d ' '
+}
+
+get_post_padding_word() {
+	local rootfs_length="$(stat -c%s "$1")"
+	[ "$rootfs_length" -ge 4 ] || return
+	rootfs_length=$((rootfs_length-4))
+
+	# the JFFS2 end marker must be on a 4K boundary (often 64K or 256K)
+	local unaligned_bytes=$((rootfs_length%4096))
+	[ "$unaligned_bytes" = 0 ] || return
+
+	# skip rootfs data except the potential EOF marker
+	dd if="$1" bs=1 skip="$rootfs_length" 2>/dev/null | od -A n -N 4 -t x1 | tr -d ' '
+}
+
+get_fs_type() {
+	local magic_word="$(get_magic_word "$1")"
+
+	case "$magic_word" in
+	"3118"*)
+		echo "ubifs"
+		;;
+	"68737173")
+		local post_padding_word="$(get_post_padding_word "$1")"
+
+		case "$post_padding_word" in
+		"deadc0de")
+			echo "squashfs-jffs2"
+			;;
+		*)
+			echo "squashfs"
+			;;
+		esac
+		;;
+	*)
+		echo "unknown"
+		;;
+	esac
+}
+
+round_up() {
+	echo "$(((($1 + ($2 - 1))/ $2) * $2))"
+}