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author | Patrick Ohly <patrick.ohly@intel.com> | 2015-09-03 20:42:32 +0200 |
---|---|---|
committer | Richard Purdie <richard.purdie@linuxfoundation.org> | 2015-09-06 15:24:26 +0100 |
commit | 1e29d77d0d33ee216b43022439876863f0db39bb (patch) | |
tree | 7ea393243cee6ac458135024ae913050c848f9b9 /meta/classes/fs-uuid.bbclass | |
parent | 7fa76bd923fd643cf0984077321d6064d8ec3a2b (diff) | |
download | openembedded-core-contrib-1e29d77d0d33ee216b43022439876863f0db39bb.tar.gz |
boot loader: support root=UUID
As mentioned when introducing the VM images
(https://bugzilla.yoctoproject.org/show_bug.cgi?id=7374), the
resulting images only work when the image is mounted as a disk that
results in the hard-coded path (/dev/sda in the current
default). Using the file system UUID to find the rootfs is more
flexible.
To enable this for boot-direct.bbclass and thus image-vm.bbclass (aka
FSTYPEs vdi/vmdk/qcow2), set SYSLINUX_ROOT =
"root=UUID=<<uuid-of-rootfs>>". The rootfs image must use an ext file
system.
The special string will get replaced in the APPEND line with the
actual UUID when the boot loader (grub-efi, syslinux or gummiboot)
writes the boot loader configuration files. At that time, the rootfs
image has already been created and its UUID can be extracted using
"tune2fs -l", which also should be available because the
e2fsprogs-native tools were needed to create the image in the first
place.
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Diffstat (limited to 'meta/classes/fs-uuid.bbclass')
-rw-r--r-- | meta/classes/fs-uuid.bbclass | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/meta/classes/fs-uuid.bbclass b/meta/classes/fs-uuid.bbclass new file mode 100644 index 0000000000..bd2613cf10 --- /dev/null +++ b/meta/classes/fs-uuid.bbclass @@ -0,0 +1,24 @@ +# Extract UUID from ${ROOTFS}, which must have been built +# by the time that this function gets called. Only works +# on ext file systems and depends on tune2fs. +def get_rootfs_uuid(d): + import subprocess + rootfs = d.getVar('ROOTFS', True) + output = subprocess.check_output(['tune2fs', '-l', rootfs]) + for line in output.split('\n'): + if line.startswith('Filesystem UUID:'): + uuid = line.split()[-1] + bb.note('UUID of %s: %s' % (rootfs, uuid)) + return uuid + bb.fatal('Could not determine filesystem UUID of %s' % rootfs) + +# Replace the special <<uuid-of-rootfs>> inside a string (like the +# root= APPEND string in a syslinux.cfg or gummiboot entry) with the +# actual UUID of the rootfs. Does nothing if the special string +# is not used. +def replace_rootfs_uuid(d, string): + UUID_PLACEHOLDER = '<<uuid-of-rootfs>>' + if UUID_PLACEHOLDER in string: + uuid = get_rootfs_uuid(d) + string = string.replace(UUID_PLACEHOLDER, uuid) + return string |