boot directory prefix in grub-install (even with --root-directory)

["Grégoire Sutre" <gregoire.sutre@labri.fr>]

Hi,

grub-install copies GRUB images into ${rootdir}/boot/grub (where 
${rootdir} is empty by default and can be changed with --root-directory).

To install GRUB files on a partition that contains a /boot file, one 
must specify a non-empty --root-directory, and grub files are then 
copied into /DIR/boot/grub.  Or one could mount the partition on a mount 
point of the form DIR/boot and specify --root-directory=DIR to force 
installation into the /grub directory of the partition.  Both solutions 
are not completely satisfactory.  Is there a better one?

The problem arises e.g. with NetBSD which uses /boot for its own 
bootloader.  The script util/grub-install.in contains lines to take care 
of that situation (lines 160-172), but these lines rely on a variable 
${host_os} that is not set.  This might be deprecated code from GRUB 
Legacy's grub-install, where ${host_os} is set by a configure substitution.

An alternative solution would be to have grub-install install in 
${rootdir}/grub, with ${rootdir} equal to /boot by default.  The default 
behavior (with no --root-directory) would be the same.

The following patch implements this alternative.

Thanks for your time,

Grégoire

--- util/grub-install.in.orig	2009-12-22 11:26:01.538833717 +0100
+++ util/grub-install.in	2009-12-22 12:48:55.979476412 +0100
@@ -39,8 +39,7 @@
  fi
  grub_mkdevicemap=${sbindir}/`echo grub-mkdevicemap | sed ${transform}`
  grub_probe=${sbindir}/`echo grub-probe | sed ${transform}`
-rootdir=
-grub_prefix=`echo /boot/grub | sed ${transform}`
+rootdir=/boot
  modules=

  install_device=
@@ -66,7 +65,7 @@
    -v, --version           print the version information and exit
    --modules=MODULES       pre-load specified modules MODULES
    --root-directory=DIR    install GRUB images under the directory DIR
-                          instead of the root directory
+                          instead of ${rootdir}
    --grub-setup=FILE       use FILE as grub-setup
    --grub-mkimage=FILE     use FILE as grub-mkimage
    --grub-mkdevicemap=FILE use FILE as grub-mkdevicemap
@@ -84,7 +83,7 @@

  INSTALL_DEVICE can be a GRUB device name or a system device filename.

-grub-install copies GRUB images into the DIR/boot directory specified by
+grub-install copies GRUB images into the DIR/`echo grub | sed 
${transform}` directory specified by
  --root-directory, and uses grub-setup to install grub into the boot
  sector.

@@ -157,21 +156,7 @@
      setup_verbose="--verbose"
  fi

-# Initialize these directories here, since ROOTDIR was initialized.
-case "$host_os" in
-netbsd* | openbsd*)
-    # Because /boot is used for the boot block in NetBSD and OpenBSD, 
use /grub
-    # instead of /boot/grub.
-    grub_prefix=`echo /grub | sed ${transform}`
-    bootdir=${rootdir}
-    ;;
-*)
-    # Use /boot/grub by default.
-    bootdir=${rootdir}/boot
-    ;;
-esac
-
-grubdir=${bootdir}/`echo grub | sed ${transform}`
+grubdir=${rootdir}/`echo grub | sed ${transform}`
  device_map=${grubdir}/device.map

  grub_probe="${grub_probe} --device-map=${device_map}"
@@ -204,8 +189,7 @@
  fi

  # Create the GRUB directory if it is not present.
-test -d "$bootdir" || mkdir "$bootdir" || exit 1
-test -d "$grubdir" || mkdir "$grubdir" || exit 1
+mkdir -p "$grubdir" || exit 1

  # If --recheck is specified, remove the device map, if present.
  if test $recheck = yes; then