Labels in grub2

[Barry Jackson <zen25000@zen.co.uk>]

[-- Attachment #1: Type: text/plain, Size: 595 bytes --]

Hello,

I spoke to Colin Watson on IRC recently and asked if the use of labels 
could be made an option in grub2 in the future.

He suggested I mention it on this list.

In the meantime I have made some patches to demonstrate this idea in 
grub 1.98 which I have attached.

They work fine for me, with GRUB_USE_LABEL="true" set in 
/etc/default/grub in my Mandriva-Linux systems.

A grub.cfg produced with a patched grub2 is attached also.

I am not a professional programmer, so I would appreciate any 
constructive criticism, and your comments in general on this idea.

Thanks,

Barry Jackson

[-- Attachment #2: 10_linux.patch --]
[-- Type: text/plain, Size: 1099 bytes --]

--- /etc/grub.d/10_linux	2010-11-02 22:25:19.849508548 +0000
+++ 10_linux	2010-11-02 22:05:31.000000000 +0000
@@ -42,11 +42,17 @@
   ;;
 esac
 
+# If device has no uuid OR GRUB_DISABLE_LINUX_UUID is true OR search for dev with uuid fails (bcj)
 if [ "x${GRUB_DEVICE_UUID}" = "x" ] || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
     || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" ; then
   LINUX_ROOT_DEVICE=${GRUB_DEVICE}
 else
-  LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
+# If A label exists and GRUB_USE_LABEL=true is in /etc/default/grub  (bcj)
+   if [ "x${GRUB_DEVICE_LABEL}" != "x" ] && [ "x${GRUB_USE_LABEL}" = "xtrue" ]; then
+      LINUX_ROOT_DEVICE=LABEL=${GRUB_DEVICE_LABEL}
+   else
+      LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
+   fi
 fi
 
 linux_entry ()
@@ -111,7 +117,6 @@
   version=`echo $basename | sed -e "s,^[^0-9]*-,,g"`
   alt_version=`echo $version | sed -e "s,\.old$,,g"`
   linux_root_device_thisversion="${LINUX_ROOT_DEVICE}"
-
   initrd=
   for i in "initrd.img-${version}" "initrd-${version}.img" \
 	   "initrd-${version}" "initrd.img-${alt_version}" \

[-- Attachment #3: grub2-mkconfig.patch --]
[-- Type: text/plain, Size: 1122 bytes --]

--- /usr/sbin/grub2-mkconfig	2010-11-02 22:38:20.610505816 +0000
+++ grub2-mkconfig	2010-11-02 22:35:32.000000000 +0000
@@ -122,6 +122,11 @@
 GRUB_DEVICE="`${grub_probe} --target=device /`"
 GRUB_DEVICE_UUID="`${grub_probe} --device ${GRUB_DEVICE} --target=fs_uuid 2> /dev/null`" || true
 
+# In grub 1.98 "grub-probe --target=fs_label" is not supported so using blkid  (bcj)
+if blkid ${GRUB_DEVICE}| grep -q "LABEL=";then
+GRUB_DEVICE_LABEL=$(blkid ${GRUB_DEVICE}| grep "LABEL=" |tr -s 'LABEL=' '*' | cut -d* -f2 | cut -d'"' -f2) 
+fi
+
 # Device containing our /boot partition.  Usually the same as GRUB_DEVICE.
 GRUB_DEVICE_BOOT="`${grub_probe} --target=device /boot`"
 GRUB_DEVICE_BOOT_UUID="`${grub_probe} --device ${GRUB_DEVICE_BOOT} --target=fs_uuid 2> /dev/null`" || true
@@ -199,6 +204,8 @@
 # override them.
 export GRUB_DEVICE \
   GRUB_DEVICE_UUID \
+  GRUB_DEVICE_LABEL \
+  GRUB_USE_LABEL \
   GRUB_DEVICE_BOOT \
   GRUB_DEVICE_BOOT_UUID \
   GRUB_FS \
@@ -226,6 +233,8 @@
   GRUB_INIT_TUNE \
   GRUB_SAVEDEFAULT
 
+
+
 if test "x${grub_cfg}" != "x"; then
   rm -f ${grub_cfg}.new
   exec > ${grub_cfg}.new

[-- Attachment #4: grub-mkconfig_lib.patch --]
[-- Type: text/plain, Size: 771 bytes --]

--- /usr/lib/grub/grub-mkconfig_lib	2010-10-23 15:16:16.000000000 +0100
+++ grub-mkconfig_lib	2010-11-02 22:31:03.000000000 +0000
@@ -120,10 +120,15 @@
 
   # If there's a filesystem UUID that GRUB is capable of identifying, use it;
   # otherwise set root as per value in device.map.
+# If a label is available and GRUB_USE_LABEL=true then use label (bcj)
+if [ "x${GRUB_DEVICE_LABEL}" != "x" ] && [ "x${GRUB_USE_LABEL}" = "xtrue" ]; then
+  echo "search --no-floppy --label --set ${GRUB_DEVICE_LABEL}"
+else
   echo "set root='`${grub_probe} --device ${device} --target=drive`'"
   if fs_uuid="`${grub_probe} --device ${device} --target=fs_uuid 2> /dev/null`" ; then
     echo "search --no-floppy --fs-uuid --set ${fs_uuid}"
   fi
+fi
 }
 
 grub_file_is_not_garbage ()

[-- Attachment #5: grub.cfg --]
[-- Type: text/plain, Size: 3167 bytes --]

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by /usr/sbin/grub2-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
  load_env
fi
set default="0"
if [ ${prev_saved_entry} ]; then
  set saved_entry=${prev_saved_entry}
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z ${boot_once} ]; then
    saved_entry=${chosen}
    save_env saved_entry
  fi
}
insmod ext2
search --no-floppy --label --set 2010_1_64_root
if loadfont /usr/share/grub/unicode.pf2 ; then
  set gfxmode=auto
  insmod gfxterm
  insmod vbe
  if terminal_output gfxterm ; then true ; else
    # For backward compatibility with versions of terminal.mod that don't
    # understand terminal_output
    terminal gfxterm
  fi
fi
insmod ext2
search --no-floppy --label --set 2010_1_64_root
set locale_dir=($root)/boot/grub2/locale
set lang=en
insmod gettext
set timeout=5
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/10_linux ###
menuentry "Mandriva GNU/Linux, with Linux 2.6.33.7-desktop-69mib" --class mandriva --class gnu-linux --class gnu --class os {
	set gfxpayload=keep
	insmod ext2
	search --no-floppy --label --set 2010_1_64_root
	echo	Loading Linux 2.6.33.7-desktop-69mib ...
	linux	/boot/vmlinuz-2.6.33.7-desktop-69mib root=LABEL=2010_1_64_root ro  splash=verbose
	echo	Loading initial ramdisk ...
	initrd	/boot/initrd-2.6.33.7-desktop-69mib.img
}
menuentry "Mandriva GNU/Linux, with Linux 2.6.33.7-desktop-2mnb" --class mandriva --class gnu-linux --class gnu --class os {
	set gfxpayload=keep
	insmod ext2
	search --no-floppy --label --set 2010_1_64_root
	echo	Loading Linux 2.6.33.7-desktop-2mnb ...
	linux	/boot/vmlinuz-2.6.33.7-desktop-2mnb root=LABEL=2010_1_64_root ro  splash=verbose
	echo	Loading initial ramdisk ...
	initrd	/boot/initrd-2.6.33.7-desktop-2mnb.img
}
menuentry "Mandriva GNU/Linux, with Linux 2.6.33.7-desktop-1mnb" --class mandriva --class gnu-linux --class gnu --class os {
	set gfxpayload=keep
	insmod ext2
	search --no-floppy --label --set 2010_1_64_root
	echo	Loading Linux 2.6.33.7-desktop-1mnb ...
	linux	/boot/vmlinuz-2.6.33.7-desktop-1mnb root=LABEL=2010_1_64_root ro  splash=verbose
	echo	Loading initial ramdisk ...
	initrd	/boot/initrd-2.6.33.7-desktop-1mnb.img
}
menuentry "Mandriva GNU/Linux, with Linux desktop" --class mandriva --class gnu-linux --class gnu --class os {
	insmod ext2
	search --no-floppy --label --set 2010_1_64_root
	echo	Loading Linux desktop ...
	linux	/boot/vmlinuz-desktop root=LABEL=2010_1_64_root ro  splash=verbose
	echo	Loading initial ramdisk ...
	initrd	/boot/initrd-desktop.img
}
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/90_persistent ###
### END /etc/grub.d/90_persistent ###