Ubuntu: needed for Wubi
Description: Change prepare_grub_to_access_device to handle filesystems
 loop-mounted on file images.
UbuntuSpecific: Not inherently. losetup and /proc/mounts are Linux-specific,
 though, so we might need to refine this before sending it upstream.

diff -Nur -x '*.orig' -x '*~' grub2-1.97~beta3/util/grub-mkconfig_lib.in grub2-1.97~beta3.new/util/grub-mkconfig_lib.in
--- grub2-1.97~beta3/util/grub-mkconfig_lib.in	2009-09-15 00:23:50.000000000 +0100
+++ grub2-1.97~beta3.new/util/grub-mkconfig_lib.in	2009-09-15 00:31:31.000000000 +0100
@@ -142,6 +142,20 @@
 {
   device=$1
 
+  loop_file=
+  case ${device} in
+    /dev/loop/*|/dev/loop[0-9])
+      loop_file=`losetup ${device} | sed -e "s/^[^(]*(\([^)]\+\)).*/\1/"`
+      case $loop_file in
+        /dev/*) ;;
+        *)
+          loop_device=${device}
+          device=`${grub_probe} --target=device "${loop_file}"`
+        ;;
+      esac
+    ;;
+  esac
+
   # Abstraction modules aren't auto-loaded.
   abstraction="`${grub_probe} --device ${device} --target=abstraction`"
   for module in ${abstraction} ; do 
@@ -159,6 +173,14 @@
   if fs_uuid="`${grub_probe} --device ${device} --target=fs_uuid 2> /dev/null`" ; then
     echo "search --no-floppy --fs-uuid --set ${fs_uuid}"
   fi
+
+  if [ "x${loop_file}" != x ]; then
+    loop_mountpoint="$(awk '"'${loop_file}'" ~ "^"$2 && $2 != "/" { print $2 }' /proc/mounts | tail -n1)"
+    if [ "x${loop_mountpoint}" != x ]; then
+      echo "loopback loop0 ${loop_file#$loop_mountpoint}"
+      echo "set root=(loop0)"
+    fi
+  fi
 }
 
 grub_file_is_not_garbage ()