[OE-core] [PATCH 1/1] Move boot media to /media/realroot for easy access after boot.

[Brian Lloyd]

There are cases where software after boot may need to know the
current boot disk.  Under the current system, it is not guaranteed
which disk is the boot.  While /media/sda is a good guess, it
isn't always right, nor is it a good assumption that only one boot
disk is in the system.  This gives a standard path to the original
boot disk mount which can be used to, for instance, update the
syslinux file on the boot media with a newer kernel, or updating
the boot parameters to add user options for future boots.  Knowing
which disk is the boot media keeps from updating the non-boot
disk when for instance multiple syslinux boot medias are plugged in
(ie ensure correct syslinux is updated when the booted system is
updated).

Signed-off-by: Brian Lloyd <blloyd at familyhonor.net>
---
 meta/recipes-core/initrdscripts/files/init-live.sh         | 10 +++++++++-
 meta/recipes-core/initrdscripts/initramfs-live-boot_1.0.bb |  4 ++--
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/meta/recipes-core/initrdscripts/files/init-live.sh b/meta/recipes-core/initrdscripts/files/init-live.sh
index 0be9b6f..d9ff2ea 100644
--- a/meta/recipes-core/initrdscripts/files/init-live.sh
+++ b/meta/recipes-core/initrdscripts/files/init-live.sh
@@ -8,6 +8,8 @@ MOUNT="/bin/mount"
 UMOUNT="/bin/umount"
 ISOLINUX=""
 
+ROOT_DISK=""
+
 # Copied from initramfs-framework. The core of this script probably should be
 # turned into initramfs-framework modules to reduce duplication.
 udev_daemon() {
@@ -80,6 +82,10 @@ boot_live_root() {
     udevadm settle --timeout=3 --quiet
     killall "${_UDEV_DAEMON##*/}" 2>/dev/null
 
+    # Allow for identification of the real root even after boot
+    mkdir -p  ${ROOT_MOUNT}/media/realroot
+    mount -n --move "/run/media/${ROOT_DISK}" ${ROOT_MOUNT}/media/realroot
+
     # Move the mount points of some filesystems over to
     # the corresponding directories under the real root filesystem.
     for dir in `awk '/\/dev.* \/run\/media/{print $2}' /proc/mounts`; do
@@ -116,10 +122,12 @@ do
   for i in `ls /run/media 2>/dev/null`; do
       if [ -f /run/media/$i/$ROOT_IMAGE ] ; then
 		found="yes"
+		ROOT_DISK="$i"
 		break
 	  elif [ -f /run/media/$i/isolinux/$ROOT_IMAGE ]; then
 		found="yes"
 		ISOLINUX="isolinux"
+		ROOT_DISK="$i"
 		break	
       fi
   done
@@ -150,7 +158,7 @@ mount_and_boot() {
     mkdir $ROOT_MOUNT
     mknod /dev/loop0 b 7 0 2>/dev/null
 
-    if ! mount -o rw,loop,noatime,nodiratime /run/media/$i/$ISOLINUX/$ROOT_IMAGE $ROOT_MOUNT ; then
+    if ! mount -o rw,loop,noatime,nodiratime /run/media/$ROOT_DISK/$ISOLINUX/$ROOT_IMAGE $ROOT_MOUNT ; then
 	fatal "Could not mount rootfs image"
     fi
 
diff --git a/meta/recipes-core/initrdscripts/initramfs-live-boot_1.0.bb b/meta/recipes-core/initrdscripts/initramfs-live-boot_1.0.bb
index 2d378e2..ac54902 100644
--- a/meta/recipes-core/initrdscripts/initramfs-live-boot_1.0.bb
+++ b/meta/recipes-core/initrdscripts/initramfs-live-boot_1.0.bb
@@ -5,7 +5,7 @@ DEPENDS = "virtual/kernel"
 RDEPENDS_${PN} = "udev udev-extraconf"
 SRC_URI = "file://init-live.sh"
 
-PR = "r11"
+PR = "r12"
 
 do_install() {
         install -m 0755 ${WORKDIR}/init-live.sh ${D}/init
@@ -13,5 +13,5 @@ do_install() {
 
 FILES_${PN} += " /init "
 
-# Due to kernel depdendency
+# Due to kernel dependency
 PACKAGE_ARCH = "${MACHINE_ARCH}"
-- 
1.9.0