[OE-core] [PATCH] boot-directdisk: allow specifying custom MBR disk signature
Darren Hart
dvhart at linux.intel.com
Wed Jul 10 17:03:57 UTC 2013
On Wed, 2013-07-10 at 13:19 +1000, Jonathan Liu wrote:
Thanks for your patience with this Jonathan.
> This introduces a DISK_SIGNATURE variable that allows controlling the
> 32-bit MBR disk signature. By default it is set to an automatically
> generated disk signature but it may by overridden in the image recipe
> by setting DISK_SIGNATURE to a 8 digit hex string.
>
> This DISK_SIGNATURE variable can also be used in the image recipe to
> specify the root by UUID using:
> SYSLINUX_ROOT = "root=PARTUUID=${DISK_SIGNATURE}-02"
This DISK_SIGNATURE variable needs to be documented, Scott R on Cc for
that.
>
> Specifying the root by UUID allows the kernel to locate the root
> filesystem even if the device name changes (e.g. /dev/hda2, /dev/hdb2 or
> /dev/sdb2 instead of /dev/sda2) due to differences in hardware
> configuration.
>
> Signed-off-by: Jonathan Liu <net147 at gmail.com>
In the future, please Cc the people you are collaborating with and use
a tool like git send-email to automatically parse that and Cc them on
the patch submission. You can also use the create-pull-request and
send-pull-request scripts which automate this process (these should
probably be updated to allow for just sending the email without a pull
repo though):
Cc: Darren Hart <dvhart at linux.intel.com>
Then they will respond with their review:
Acked-by: Darren hart <dvhart at linux.intel.com>
> ---
> meta/classes/boot-directdisk.bbclass | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/meta/classes/boot-directdisk.bbclass b/meta/classes/boot-directdisk.bbclass
> index 3169043..182957b 100644
> --- a/meta/classes/boot-directdisk.bbclass
> +++ b/meta/classes/boot-directdisk.bbclass
> @@ -34,6 +34,7 @@ BOOTDD_EXTRA_SPACE ?= "16384"
> # Get the build_syslinux_cfg() function from the syslinux class
>
> AUTO_SYSLINUXCFG = "1"
> +DISK_SIGNATURE ?= "${DISK_SIGNATURE_GENERATED}"
> SYSLINUX_ROOT ?= "root=/dev/sda2"
> SYSLINUX_TIMEOUT ?= "10"
>
> @@ -80,6 +81,9 @@ build_boot_dd() {
> parted $IMAGE set 1 boot on
> parted $IMAGE print
>
> + echo -ne "$(echo ${DISK_SIGNATURE} | fold -w 2 | tac | paste -sd '' | sed 's/\(..\)/\\x&/g')" | \
> + dd of=$IMAGE bs=1 seek=440 conv=notrunc
> +
> OFFSET=`expr $END2 / 512`
> dd if=${STAGING_DATADIR}/syslinux/mbr.bin of=$IMAGE conv=notrunc
> dd if=$HDDIMG of=$IMAGE conv=notrunc seek=1 bs=512
> @@ -91,8 +95,24 @@ build_boot_dd() {
> }
>
> python do_bootdirectdisk() {
> + validate_disk_signature(d)
> bb.build.exec_func('build_syslinux_cfg', d)
> bb.build.exec_func('build_boot_dd', d)
> }
>
> +def generate_disk_signature():
> + import uuid
> +
> + return str(uuid.uuid4())[:8]
> +
> +def validate_disk_signature(d):
> + import re
> +
> + disk_signature = d.getVar("DISK_SIGNATURE", True)
> +
> + if not re.match(r'^[0-9a-fA-F]{8}$', disk_signature):
> + bb.fatal("DISK_SIGNATURE '%s' must be an 8 digit hex string" % disk_signature)
> +
> +DISK_SIGNATURE_GENERATED := "${@generate_disk_signature()}"
> +
> addtask bootdirectdisk before do_build
--
Darren Hart
Intel Open Source Technology Center
Yocto Project - Technical Lead - Linux Kernel
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