[OE-core] [PATCH] boot-directdisk: allow specifying custom MBR disk signature
Jonathan Liu
net147 at gmail.com
Wed Jul 10 03:19:45 UTC 2013
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=${DISK_SIGNATURE}-02"
Specifying the root by UUID allows the kernel to locate the root
filesystem even if the device name changes (e.g. /dev/hda2, /dev/hdb2 or
/dev/sdb2 instead of /dev/sda2) due to differences in hardware
configuration.
Signed-off-by: Jonathan Liu <net147 at gmail.com>
---
meta/classes/boot-directdisk.bbclass | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/meta/classes/boot-directdisk.bbclass b/meta/classes/boot-directdisk.bbclass
index 3169043..182957b 100644
--- a/meta/classes/boot-directdisk.bbclass
+++ b/meta/classes/boot-directdisk.bbclass
@@ -34,6 +34,7 @@ BOOTDD_EXTRA_SPACE ?= "16384"
# Get the build_syslinux_cfg() function from the syslinux class
AUTO_SYSLINUXCFG = "1"
+DISK_SIGNATURE ?= "${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
--
1.8.3.2
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