[OE-core] [PATCH] core-image-minimal-initramfs: prepare initramfs for NFS boot

Mon Mar 12 16:59:14 UTC 2018

Hi.

It'd be nice if this was part of initramfs-framework instead.

In particular some devices need a bit more than ifconfig & route, e.g.
configuration of SoC internal Ethernet switches.

As it is, this patch is not very generic, whereas if it was integrated with
the initramfs-framework, another module could take care of the driver /
hardware specifics, and this module would just do the actual mounting of the
ROOTFS.

The remaining bits, like mount --move of /proc are also already part of
initramfs-framework.

That way, this new addition would be useful on a wide range of devices.

Cheers,
Andre'

On Mon, 2018-03-12 at 16:33 +0200, Oleksii Konoplitskyi wrote:
> It helps to boot device by mounting rootfs via NFS when network
> drivers are built as modules.
> We include modules in core-image-minimal-initramfs image
> and start kernel with specifying custom rdinit in cmdline:
>    rdinit=/init-nfs.sh
> 
> NFS and IP parameters should be passed to kernel as usual.
> For example:
>    ip=192.168.0.11::192.168.0.1:255.255.255.0:linux:eth0:off
>    nfsroot=192.168.0.10:/exported_nfs,nfsvers=3,tcp
>    root=/dev/nfs rw loglevel=7 rdinit=/init-nfs.sh
> 
> To use this initramfs, one could put the following
> to conf/local.conf:
>    INITRAMFS_LOAD_KERNEL_MODULES = "kernel-module-igb"
>    INITRAMFS_IMAGE_BUNDLE = "1"
>    INITRAMFS_IMAGE = "core-image-minimal-initramfs"
> 
> INITRAMFS_LOAD_KERNEL_MODULES is a space-separated list of
> modules that will be added to initramfs.
> 
> Signed-off-by: Andrii Bordunov <aborduno at cisco.com>
> Signed-off-by: Oleksii Konoplitskyi <okonopli at cisco.com>
> ---
>  .../images/core-image-minimal-initramfs.bb         |   2 +-
>  meta/recipes-core/initrdscripts/files/init-nfs.sh  | 108
> +++++++++++++++++++++
>  .../initrdscripts/initramfs-nfs-boot_1.0.bb        |  14 +++
>  3 files changed, 123 insertions(+), 1 deletion(-)
>  create mode 100644 meta/recipes-core/initrdscripts/files/init-nfs.sh
>  create mode 100644 meta/recipes-core/initrdscripts/initramfs-nfs-
> boot_1.0.bb
> 
> diff --git a/meta/recipes-core/images/core-image-minimal-initramfs.bb
> b/meta/recipes-core/images/core-image-minimal-initramfs.bb
> index c446e87..bf794bf 100644
> --- a/meta/recipes-core/images/core-image-minimal-initramfs.bb
> +++ b/meta/recipes-core/images/core-image-minimal-initramfs.bb
> @@ -3,7 +3,7 @@ DESCRIPTION = "Small image capable of booting a device.
> The kernel includes \
>  the Minimal RAM-based Initial Root Filesystem (initramfs), which finds
> the \
>  first 'init' program more efficiently."
>  
> -PACKAGE_INSTALL = "initramfs-live-boot initramfs-live-install initramfs-
> live-install-efi ${VIRTUAL-RUNTIME_base-utils} udev base-passwd
> ${ROOTFS_BOOTSTRAP_INSTALL}"
> +PACKAGE_INSTALL = "initramfs-live-boot initramfs-live-install initramfs-
> live-install-efi ${VIRTUAL-RUNTIME_base-utils} udev base-passwd
> ${ROOTFS_BOOTSTRAP_INSTALL} initramfs-nfs-boot"
>  
>  # Do not pollute the initrd image with rootfs features
>  IMAGE_FEATURES = ""
> diff --git a/meta/recipes-core/initrdscripts/files/init-nfs.sh
> b/meta/recipes-core/initrdscripts/files/init-nfs.sh
> new file mode 100644
> index 0000000..31a55ec
> --- /dev/null
> +++ b/meta/recipes-core/initrdscripts/files/init-nfs.sh
> @@ -0,0 +1,108 @@
> +#!/bin/sh
> +
> +CONSOLE="/dev/console"
> +PATH=/sbin:/bin:/usr/sbin:/usr/bin
> +ROOT_MOUNT="/rootfs"
> +
> +fatal()
> +{
> +	echo $1 >$CONSOLE
> +	echo >$CONSOLE
> +	exec sh
> +}
> +
> +net_up()
> +{
> +	[ "$(ifconfig $PARAM_IFNAME | awk '/inet addr/{print
> substr($2,6)}')" = "$PARAM_IP" ] && return
> +	#load all ethernet drivers if network interface is not configured
> +	MODULES="$(find /lib/modules/*/kernel/drivers/net/ethernet -name
> \*.ko | sed -e 's,^.*/,,' -e 's,\.ko$,,')"
> +	[ -z "$MODULES" ] && fatal "Ethernet drivers list is emty.
> Nothing to load."
> +	modprobe -a $MODULES
> +
> +	ifconfig $PARAM_IFNAME $PARAM_IP netmask $PARAM_NETMASK ||
> +		fatal "Failed to configure ethernet interface"
> +	route add default gw $PARAM_GW ||
> +		fatal "Failed to set default gateway"
> +}
> +
> +
> +#TODO: IPv6 is not supported yet
> +mount_nfs()
> +{
> +	mkdir $ROOT_MOUNT
> +	for i in $(seq 1 10)
> +	do
> +		mount -t nfs "$PARAM_NFSROOT_PATH" -o
> nolock,"$PARAM_NFSROOT_OPTS" $ROOT_MOUNT && return
> +		sleep 1
> +	done
> +	fatal "Could not mount rootfs via nfs"
> +}
> +
> +
> +early_setup()
> +{
> +	mkdir -p /proc
> +	mkdir -p /sys
> +	mount -t proc proc /proc
> +	mount -t sysfs sysfs /sys
> +	mount -t devtmpfs none /dev
> +
> +	mkdir -p /run
> +	mkdir -p /var/run
> +}
> +
> +
> +#TODO: IPv6 is not supported yet
> +read_args()
> +{
> +	[ -z "$CMDLINE" ] && CMDLINE=$(cat /proc/cmdline)
> +	for arg in $CMDLINE; do
> +		optarg=$(expr "x$arg" : 'x[^=]*=\(.*\)'$)
> +		case $arg in
> +		ip=*)
> +			PARAM_IFNAME=$(echo "$optarg" | cut -d: -f6)
> +			PARAM_IP_ALL=$(echo "$optarg" | grep -Eo '([0-
> 9]{1,3}\.){3}[0-9]{1,3}')
> +			PARAM_IP=$(echo "$PARAM_IP_ALL" | sed -n 1p)
> +			PARAM_GW=$(echo "$PARAM_IP_ALL" | sed -n 2p)
> +			PARAM_NETMASK=$(echo "$PARAM_IP_ALL" | sed -n 3p)
> +			;;
> +		nfsroot=*)
> +			PARAM_NFSROOT_PATH=$(echo "$optarg" | cut -d,
> -f1)
> +			PARAM_NFSROOT_OPTS=$(echo "$optarg" | cut -d,
> -f2-)
> +			;;
> +		debugshell)
> +			DEBUGSHELL=1
> +			;;
> +		esac
> +	done
> +}
> +
> +boot_nfs()
> +{
> +	touch $ROOT_MOUNT/bin || fatal "Rootfs is not writeable"
> +
> +	mount -n --move /proc ${ROOT_MOUNT}/proc
> +	mount -n --move /sys ${ROOT_MOUNT}/sys
> +	mount -n --move /dev ${ROOT_MOUNT}/dev
> +
> +	cd $ROOT_MOUNT
> +
> +	# busybox switch_root supports -c option
> +	exec switch_root -c /dev/console $ROOT_MOUNT /sbin/init $CMDLINE
> ||
> +		fatal "Couldn't switch_root, dropping to shell"
> +}
> +
> +early_setup
> +
> +read_args
> +
> +if [ -n "$DEBUGSHELL" ]; then
> +	exec sh
> +fi
> +
> +net_up
> +
> +mount_nfs
> +
> +boot_nfs
> +
> diff --git a/meta/recipes-core/initrdscripts/initramfs-nfs-boot_1.0.bb
> b/meta/recipes-core/initrdscripts/initramfs-nfs-boot_1.0.bb
> new file mode 100644
> index 0000000..ca4f191
> --- /dev/null
> +++ b/meta/recipes-core/initrdscripts/initramfs-nfs-boot_1.0.bb
> @@ -0,0 +1,14 @@
> +SUMMARY = "Live image init script"
> +LICENSE = "MIT"
> +LIC_FILES_CHKSUM =
> "file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
> +RDEPENDS_${PN} = "${@['', d.getVar('INITRAMFS_LOAD_KERNEL_MODULES',
> True)][d.getVar('INITRAMFS_LOAD_KERNEL_MODULES', True) is not None]}"
> +SRC_URI = "file://init-nfs.sh"
> +
> +S = "${WORKDIR}"
> +
> +do_install() {
> +        install -m 0755 ${WORKDIR}/init-nfs.sh ${D}/init-nfs.sh
> +}
> +
> +FILES_${PN} += " /init-nfs.sh "
> +
> -- 
> 2.7.4
> 