Fix for bug 86487. Allowing a subdirectory of a block device to be chrooted from and booted. New cmdline option subdir=

git-svn-id: svn+ssh://svn.gentoo.org/var/svnroot/genkernel/trunk@218 67a159dc-881f-0410-a524-ba9dfbe2cb84

generic/linuxrc

@@ -45,6 +45,9 @@ do
       real_root\=*)
 	  REAL_ROOT=`parse_opt "${x}"`
 	  ;;
+      subdir\=*)
+	  SUBDIR=`parse_opt "${x}"`
+	  ;;
       real_init\=*)
 	  REAL_INIT=`parse_opt "${x}"`
 	  ;;
@@ -461,6 +464,12 @@ else
 	mkdir -p ${NEW_ROOT}/tmp/.initrd
 fi
 
+if [ "${SUBDIR}" != '' -a -e "${CHROOT}/${SUBDIR}" ]
+then
+    good_msg"Entering ${SUBDIR} to boot"
+    CHROOT=${CHROOT}/${SUBDIR}
+fi
+
 if [ "$0" = '/linuxrc' ]
 then
 	[ ! -e ${CHROOT}/dev/console ] && mknod ${CHROOT}/dev/console c 5 1