5 files changed, 67 insertions, 57 deletions

diff --git a/README.md b/README.md
index 8f037b3..00ed942 100644
--- a/README.md
+++ b/README.md
@@ -57,18 +57,48 @@ If you use this layer you do *not* need to set `read-only-rootfs` in the
 
 ## Kernel command line parameters
 
-Example:
+### Example using initrd:
 
 ```
-root=/dev/sda1 rootfstype=ext4 rootrw=/dev/sda2 rootrwfstype=btrfs
+root=/dev/sda1 rootrw=/dev/sda2
 ```
 
+This cmd line start `/sbin/init` with the `/dev/sda1` partition as the read-only
+rootfs and the `/dev/sda2` partition as the read-write persistend state.
+
+```
+root=/dev/sda1 rootrw=/dev/sda2 init=/bin/sh
+```
+
+The same as before but it now starts `/bin/sh` instead of `/sbin/init`.
+
+### Example without initrd:
+
+```
+root=/dev/sda1 rootrw=/dev/sda2 init=/init
+```
+
+This cmd line starts `/sbin/init` with `/dev/sda1` partition as the read-only
+rootfs and the `/dev/sda2` partition as the read-write persistend state. When
+using this init script without an initrd, `init=/init` has to be set.
+
+```
+root=/dev/sda1 rootrw=/dev/sda2 init=/init rootinit=/bin/sh
+```
+
+The same as before but it now starts `/bin/sh` instead of `/sbin/init`
+
+### Details
+
 `root=` specifies the read-only root filesystem device. If this is not
 specified, the current rootfs is used.
 
 `rootfstype=` if support for the-read only filesystem is not build into the
 kernel, you can specifiy the required module name here.
 
+`rootinit=` if the `init` parameter was used to specify this init script,
+`rootinit` can be used to overwrite the default (`/sbin/init`).
+
 `rootrw=` specifies the read-write filesystem device. If this is not
 specified, `tmpfs` is used.
 
diff --git a/recipes-core/initrdscripts/files/init-readonly-rootfs-overlay-boot.sh b/recipes-core/initrdscripts/files/init-readonly-rootfs-overlay-boot.sh
index 37a1635..4c70753 100644
--- a/recipes-core/initrdscripts/files/init-readonly-rootfs-overlay-boot.sh
+++ b/recipes-core/initrdscripts/files/init-readonly-rootfs-overlay-boot.sh
@@ -9,6 +9,7 @@ MOUNT="/bin/mount"
 UMOUNT="/bin/umount"
 
 INIT="/sbin/init"
+ROOT_ROINIT="/sbin/init"
 
 ROOT_MOUNT="/mnt"
 ROOT_RODEVICE=""
@@ -17,35 +18,12 @@ ROOT_ROMOUNT="/media/rfs/ro"
 ROOT_RWMOUNT="/media/rfs/rw"
 ROOT_RWRESET="no"
 
-# Copied from initramfs-framework. The core of this script probably should be
-# turned into initramfs-framework modules to reduce duplication.
-udev_daemon() {
-        OPTIONS="/sbin/udev/udevd /sbin/udevd /lib/udev/udevd /lib/systemd/systemd-udevd"
-
-        for o in $OPTIONS; do
-                if [ -x "$o" ]; then
-                        echo $o
-                        return 0
-                fi
-        done
-
-        return 1
-}
-
-_UDEV_DAEMON=`udev_daemon`
-
 early_setup() {
     mkdir -p /proc
     mkdir -p /sys
     $MOUNT -t proc proc /proc
     $MOUNT -t sysfs sysfs /sys
-    $MOUNT -t devtmpfs none /dev
-
-    mkdir -p /run
-    mkdir -p /var/run
-
-    $_UDEV_DAEMON --daemon
-    udevadm trigger --action=add
+    grep -w "/dev" /proc/mounts >/dev/null || $MOUNT -t devtmpfs none /dev
 }
 
 read_args() {
@@ -57,6 +35,8 @@ read_args() {
                 ROOT_RODEVICE=$optarg ;;
             rootfstype=*)
                 modprobe $optarg 2> /dev/null ;;
+            rootinit=*)
+                ROOT_ROINIT=$optarg ;;
             rootrw=*)
                 ROOT_RWDEVICE=$optarg ;;
             rootrwfstype=*)
@@ -108,6 +88,13 @@ mount_and_boot() {
         fatal "Could not mount read-only rootfs"
     fi
 
+    # If future init is the same as current file, use $ROOT_ROINIT
+    # Tries to avoid loop to infinity if init is set to current file via
+    # kernel commandline
+    if cmp -s "$0" "$INIT"; then
+        INIT="$ROOT_ROINIT"
+    fi
+
     # Build mount options for read write root filesystem.
     # If no read-write device was specified via kernel commandline, use tmpfs.
     if [ -z "${ROOT_RWDEVICE}" ]; then
@@ -128,9 +115,9 @@ mount_and_boot() {
 
     # Determine which unification filesystem to use
     union_fs_type=""
-    if grep -w "overlay" /proc/filesystems; then
+    if grep -w "overlay" /proc/filesystems >/dev/null; then
         union_fs_type="overlay"
-    elif grep -w "aufs" /proc/filesystems; then
+    elif grep -w "aufs" /proc/filesystems >/dev/null; then
         union_fs_type="aufs"
     else
         union_fs_type=""
@@ -155,21 +142,6 @@ mount_and_boot() {
     $MOUNT -n --move $ROOT_ROMOUNT ${ROOT_MOUNT}/$ROOT_ROMOUNT
     $MOUNT -n --move $ROOT_RWMOUNT ${ROOT_MOUNT}/$ROOT_RWMOUNT
 
-    # Watches the udev event queue, and exits if all current events are handled
-    udevadm settle --timeout=3
-    # Kills the current udev running processes, which survived after
-    # device node creation events were handled, to avoid unexpected behavior
-    killall -9 "${_UDEV_DAEMON##*/}" 2>/dev/null
-
-    # Remove /run /var/run that are created in early_setup
-    rm -rf /run /var/run
-
-    # 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
-        mkdir -p ${ROOT_MOUNT}/media/${dir##*/}
-        $MOUNT -n --move $dir ${ROOT_MOUNT}/media/${dir##*/}
-    done
     $MOUNT -n --move /proc ${ROOT_MOUNT}/proc
     $MOUNT -n --move /sys ${ROOT_MOUNT}/sys
     $MOUNT -n --move /dev ${ROOT_MOUNT}/dev
diff --git a/recipes-core/initrdscripts/initramfs-readonly-rootfs-overlay_1.0.bb b/recipes-core/initrdscripts/initramfs-readonly-rootfs-overlay_1.0.bb
index 7c2bdf6..164d394 100644
--- a/recipes-core/initrdscripts/initramfs-readonly-rootfs-overlay_1.0.bb
+++ b/recipes-core/initrdscripts/initramfs-readonly-rootfs-overlay_1.0.bb
@@ -1,19 +1,8 @@
-SUMMARY = "Read only rootfs with overlay init script"
-LICENSE = "MIT"
-LIC_FILES_CHKSUM = "file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
-DEPENDS = "virtual/kernel"
-RDEPENDS_${PN} = "udev"
-SRC_URI = "file://init-readonly-rootfs-overlay-boot.sh"
+require readonly-rootfs-overlay-init-script.inc
 
-S = "${WORKDIR}"
-
-do_install() {
-        install -m 0755 ${WORKDIR}/init-readonly-rootfs-overlay-boot.sh ${D}/init
+do_install_append() {
         install -d ${D}/dev
         mknod -m 622 ${D}/dev/console c 5 1
 }
 
-FILES_${PN} += " /init /dev "
-
-# Due to kernel dependency
-PACKAGE_ARCH = "${MACHINE_ARCH}"
+FILES_${PN} += "/dev"
diff --git a/recipes-core/initrdscripts/initscripts-readonly-rootfs-overlay_1.0.bb b/recipes-core/initrdscripts/initscripts-readonly-rootfs-overlay_1.0.bb
new file mode 100644
index 0000000..9428356
--- /dev/null
+++ b/recipes-core/initrdscripts/initscripts-readonly-rootfs-overlay_1.0.bb
@@ -0,0 +1 @@
+require readonly-rootfs-overlay-init-script.inc
diff --git a/recipes-core/initrdscripts/readonly-rootfs-overlay-init-script.inc b/recipes-core/initrdscripts/readonly-rootfs-overlay-init-script.inc
new file mode 100644
index 0000000..947246b
--- /dev/null
+++ b/recipes-core/initrdscripts/readonly-rootfs-overlay-init-script.inc
@@ -0,0 +1,18 @@
+SUMMARY = "Read only rootfs with overlay init script"
+LICENSE = "MIT"
+LIC_FILES_CHKSUM = "file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
+DEPENDS = "virtual/kernel"
+SRC_URI = "file://init-readonly-rootfs-overlay-boot.sh"
+
+S = "${WORKDIR}"
+
+do_install() {
+        install -m 0755 ${WORKDIR}/init-readonly-rootfs-overlay-boot.sh ${D}/init
+        install -d "${D}/media/rfs/ro"
+        install -d "${D}/media/rfs/rw"
+}
+
+FILES_${PN} += " /init /media/rfs"
+
+# Due to kernel dependency
+PACKAGE_ARCH = "${MACHINE_ARCH}"