Ping?
At 11:45 +0100 on 06 Jul (1278416753), Tim Deegan wrote:
> pygrub: look in every partition for something to boot, in case
> the OS installer (SLES 10 sp1 in particular) forgets to mark the
> boot partition as active.
>
> Signed-off-by: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
>
> diff -r 78b2f1e04c73 tools/pygrub/src/pygrub
> --- a/tools/pygrub/src/pygrub Tue Jul 06 11:09:36 2010 +0100
> +++ b/tools/pygrub/src/pygrub Tue Jul 06 11:38:42 2010 +0100
> @@ -50,21 +50,6 @@
> return True
> return False
>
> -def get_active_partition(file):
> - """Find the offset for the start of the first active partition "
> - "in the disk image file."""
> -
> - fd = os.open(file, os.O_RDONLY)
> - buf = os.read(fd, 512)
> - for poff in (446, 462, 478, 494): # partition offsets
> - # active partition has 0x80 as the first byte
> - if struct.unpack("<c", buf[poff:poff+1]) == ('\x80',):
> - return buf[poff:poff+16]
> -
> - # if there's not a partition marked as active, fall back to
> - # the first partition
> - return buf[446:446+16]
> -
> SECTOR_SIZE=512
> DK_LABEL_LOC=1
> DKL_MAGIC=0xdabe
> @@ -101,25 +86,44 @@
> FDISK_PART_SOLARIS_OLD=0x82
> FDISK_PART_GPT=0xee
>
> -def get_fs_offset(file):
> +def get_partition_offsets(file):
> if not is_disk_image(file):
> - return 0
> + # No MBR: assume whole disk filesystem, which is like a
> + # single partition starting at 0
> + return [0]
>
> - partbuf = get_active_partition(file)
> - if len(partbuf) == 0:
> - raise RuntimeError, "Unable to find active partition on disk"
> + part_offs = []
>
> - offset = struct.unpack("<L", partbuf[8:12])[0] * SECTOR_SIZE
> + fd = os.open(file, os.O_RDONLY)
> + buf = os.read(fd, 512)
> + for poff in (446, 462, 478, 494): # partition offsets
>
> - type = struct.unpack("<B", partbuf[4:5])[0]
> + # MBR contains a 16 byte descriptor per partition
> + partbuf = buf[poff:poff+16]
> + offset = struct.unpack("<L", partbuf[8:12])[0] * SECTOR_SIZE
> + type = struct.unpack("<B", partbuf[4:5])[0]
> +
> + # offset == 0 implies this partition is not enabled
> + if offset == 0:
> + continue
>
> - if type == FDISK_PART_SOLARIS or type == FDISK_PART_SOLARIS_OLD:
> - offset += get_solaris_slice(file, offset)
> + if type == FDISK_PART_SOLARIS or type == FDISK_PART_SOLARIS_OLD:
> + try:
> + offset += get_solaris_slice(file, offset)
> + except RuntimeError:
> + continue # no solaris magic at that offset, ignore partition
>
> - if type == FDISK_PART_GPT:
> - offset = get_fs_offset_gpt(file)
> -
> - return offset
> + if type == FDISK_PART_GPT:
> + offset = get_fs_offset_gpt(file)
> +
> + # Active partition has 0x80 as the first byte.
> + # If active, prepend to front of list, otherwise append to back.
> + if struct.unpack("<c", buf[poff:poff+1]) == ('\x80',):
> + part_offs.insert(0, offset)
> + else:
> + part_offs.append(offset)
> +
> + return part_offs
>
> class GrubLineEditor(curses.textpad.Textbox):
> def __init__(self, screen, startx, starty, line = ""):
> @@ -703,17 +711,40 @@
> bootfsargs = '"%s"' % incfg["args"]
> bootfsgroup = re.findall('zfs-bootfs=(.*?)[\s\,\"]', bootfsargs)
> if bootfsgroup:
> - fs = fsimage.open(file, get_fs_offset(file), bootfsgroup[0])
> + bootfsoptions = bootfsgroup[0]
> else:
> - fs = fsimage.open(file, get_fs_offset(file))
> + bootfsoptions = ""
>
> - chosencfg = sniff_solaris(fs, incfg)
> + # get list of offsets into file which start partitions
> + part_offs = get_partition_offsets(file)
>
> - if not chosencfg["kernel"]:
> - chosencfg = sniff_netware(fs, incfg)
> + for offset in part_offs:
> + try:
> + fs = fsimage.open(file, offset, bootfsoptions)
>
> - if not chosencfg["kernel"]:
> - chosencfg = run_grub(file, entry, fs, incfg["args"])
> + chosencfg = sniff_solaris(fs, incfg)
> +
> + if not chosencfg["kernel"]:
> + chosencfg = sniff_netware(fs, incfg)
> +
> + if not chosencfg["kernel"]:
> + chosencfg = run_grub(file, entry, fs, incfg["args"])
> +
> + # Break as soon as we've found the kernel so that we continue
> + # to use this fsimage object
> + if chosencfg["kernel"]:
> + break
> + fs = None
> +
> + except:
> + # IOErrors raised by fsimage.open
> + # RuntimeErrors raised by run_grub if no menu.lst present
> + fs = None
> + continue
> +
> + # Did looping through partitions find us a kernel?
> + if not fs:
> + raise RuntimeError, "Unable to find partition containing kernel"
>
> if not_really:
> bootcfg["kernel"] = "<kernel:%s>" % chosencfg["kernel"]
--
Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, XenServer Engineering
Citrix Systems UK Ltd. (Company #02937203, SL9 0BG)
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