From 1e29d77d0d33ee216b43022439876863f0db39bb Mon Sep 17 00:00:00 2001 From: Patrick Ohly Date: Thu, 3 Sep 2015 20:42:32 +0200 Subject: 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=<>". 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 Signed-off-by: Richard Purdie --- meta/classes/fs-uuid.bbclass | 24 ++++++++++++++++++++++++ meta/classes/grub-efi.bbclass | 4 ++++ meta/classes/gummiboot.bbclass | 4 ++++ meta/classes/syslinux.bbclass | 5 ++++- 4 files changed, 36 insertions(+), 1 deletion(-) create mode 100644 meta/classes/fs-uuid.bbclass 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 ${ROOTFS}, which must have been built +# by the time that this function gets called. Only works +# on ext file systems and depends on tune2fs. +def get_rootfs_uuid(d): + import subprocess + rootfs = d.getVar('ROOTFS', True) + output = subprocess.check_output(['tune2fs', '-l', rootfs]) + for line in output.split('\n'): + if line.startswith('Filesystem UUID:'): + uuid = line.split()[-1] + bb.note('UUID of %s: %s' % (rootfs, uuid)) + return uuid + bb.fatal('Could not determine filesystem UUID of %s' % rootfs) + +# Replace the special <> inside a string (like the +# root= APPEND string in a syslinux.cfg or gummiboot entry) with the +# actual UUID of the rootfs. Does nothing if the special string +# is not used. +def replace_rootfs_uuid(d, string): + UUID_PLACEHOLDER = '<>' + if UUID_PLACEHOLDER in string: + uuid = get_rootfs_uuid(d) + string = string.replace(UUID_PLACEHOLDER, uuid) + return string diff --git a/meta/classes/grub-efi.bbclass b/meta/classes/grub-efi.bbclass index 6d58d48704..4ddc2bb125 100644 --- a/meta/classes/grub-efi.bbclass +++ b/meta/classes/grub-efi.bbclass @@ -26,6 +26,9 @@ GRUB_OPTS ?= "serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1" EFIDIR = "/EFI/BOOT" +# Need UUID utility code. +inherit fs-uuid + efi_populate() { # DEST must be the root of the image so that EFIDIR is not # nested under a top level directory. @@ -129,6 +132,7 @@ python build_efi_cfg() { initrd = localdata.getVar('INITRD', True) if append: + append = replace_rootfs_uuid(d, append) cfgfile.write('%s' % (append)) cfgfile.write(' %s' % btype[1]) cfgfile.write('\n') diff --git a/meta/classes/gummiboot.bbclass b/meta/classes/gummiboot.bbclass index dae19775c3..3d9c08bbc9 100644 --- a/meta/classes/gummiboot.bbclass +++ b/meta/classes/gummiboot.bbclass @@ -15,6 +15,9 @@ GUMMIBOOT_CFG ?= "${S}/loader.conf" GUMMIBOOT_ENTRIES ?= "" GUMMIBOOT_TIMEOUT ?= "10" +# Need UUID utility code. +inherit fs-uuid + efi_populate() { DEST=$1 @@ -108,6 +111,7 @@ python build_efi_cfg() { lb = "install-efi" entrycfg.write('options LABEL=%s ' % lb) if append: + append = replace_rootfs_uuid(d, append) entrycfg.write('%s' % append) entrycfg.write('\n') entrycfg.close() diff --git a/meta/classes/syslinux.bbclass b/meta/classes/syslinux.bbclass index d6498d98bb..44ef9a9176 100644 --- a/meta/classes/syslinux.bbclass +++ b/meta/classes/syslinux.bbclass @@ -34,6 +34,9 @@ ISO_BOOTCAT = "isolinux/boot.cat" MKISOFS_OPTIONS = "-no-emul-boot -boot-load-size 4 -boot-info-table" APPEND_prepend = " ${SYSLINUX_ROOT} " +# Need UUID utility code. +inherit fs-uuid + syslinux_populate() { DEST=$1 BOOTDIR=$2 @@ -177,7 +180,7 @@ python build_syslinux_cfg () { cfgfile.write('initrd=/initrd ') cfgfile.write('LABEL=%s '% (label)) - + append = replace_rootfs_uuid(d, append) cfgfile.write('%s %s\n' % (append, btype[1])) else: cfgfile.write('APPEND %s\n' % btype[1]) -- cgit 1.2.3-korg