# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
-"""This module provides the code for handling OpenBSD disklabels"""
+"""This module provides the code for handling BSD disklabels"""
import struct
import sys
+import os
import cStringIO
import optparse
BBSIZE = 8192 # size of boot area with label
SBSIZE = 8192 # max size of fs superblock
-DISKMAGIC = 0x82564557
-
class MBR(object):
"""Represents a Master Boot Record."""
ret += "Partition %d: %s\n" % (i, self.part[i])
ret += "Signature: %s %s\n" % (hex(ord(self.signature[0])),
hex(ord(self.signature[1])))
- return ret
+ title = "Master Boot Record"
+ return "%s\n%s\n%s\n" % (title, len(title) * "=", ret)
class Disklabel:
+ """Represents an BSD Disklabel"""
+
+ def __init__(self, disk):
+ """Create a DiskLabel instance"""
+ self.disk = disk
+ self.part_num = None
+ self.disklabel = None
+
+ with open(disk, "rb") as d:
+ sector0 = d.read(BLOCKSIZE)
+ self.mbr = MBR(sector0)
+
+ for i in range(4):
+ ptype = self.mbr.part[i].type
+ if ptype in (0xa5, 0xa6, 0xa9):
+ d.seek(BLOCKSIZE * self.mbr.part[i].first_sector)
+ self.part_num = i
+ if ptype == 0xa5: # FreeBSD
+ self.disklabel = BSD_Disklabel(d)
+ elif ptype == 0xa6: # OpenBSD
+ self.disklabel = OpenBSD_Disklabel(d)
+ else: # NetBSD
+ self.disklabel = BSD_Disklabel(d)
+ break
+
+ assert self.disklabel is not None, "No *BSD partition found"
+
+ def write(self):
+ """Write the disklabel back to the media"""
+ with open(self.disk, 'rw+b') as d:
+ d.write(self.mbr.pack())
+
+ d.seek(self.mbr.part[self.part_num].first_sector * BLOCKSIZE)
+ self.disklabel.write_to(d)
+
+ def __str__(self):
+ return str(self.mbr) + str(self.disklabel)
+
+ def enlarge_disk(self, new_size):
+ """Enlarge the size of the disk and return the last usable sector"""
+
+ # Fix the disklabel
+ end = self.disklabel.enlarge_disk(new_size)
+
+ # Fix the MBR
+ start = self.mbr.part[self.part_num].first_sector
+ self.mbr.part[self.part_num].sector_count = end - start + 1
+
+ cylinder = end // (self.disklabel.ntracks * self.disklabel.nsectors)
+ header = (end // self.disklabel.nsectors) % self.disklabel.ntracks
+ sector = (end % self.disklabel.nsectors) + 1
+ chs = MBR.Partition.pack_chs(cylinder, header, sector)
+ self.mbr.part[self.part_num].end = chs
+
+ def enlarge_last_partition(self):
+ self.disklabel.enlarge_last_partition()
+
+
+class BSD_Disklabel:
+ pass
+
+
+class OpenBSD_Disklabel:
"""Represents an OpenBSD Disklabel"""
format = "<IHH16s16sIIIIII8sIHHIII20sHH16sIHHII364s"
"""
tmp.frag, tmp.cpg)
def getpsize(self, i):
+ """Get size for partition i"""
return (self.part[i].sizeh << 32) + self.part[i].size
def setpoffset(self, i, offset):
- """Set offset for partition i"""
+ """Set offset for partition i"""
tmp = self.part[i]
self.part[i] = self.Partition(tmp.size, offset & 0xffffffff,
offset >> 32, tmp.sizeh, tmp.frag,
tmp.cpg)
def getpoffset(self, i):
+ """Get offset for partition i"""
return (self.part[i].offseth << 32) + self.part[i].offset
- def __init__(self, disk):
- """Create a DiskLabel instance"""
- self.disk = disk
- self.part_num = None
-
- with open(disk, "rb") as d:
- sector0 = d.read(BLOCKSIZE)
- self.mbr = MBR(sector0)
-
- for i in range(4):
- if self.mbr.part[i].type == 0xa6: # OpenBSD type
- self.part_num = i
- break
+ DISKMAGIC = 0x82564557
- assert self.part_num is not None, "No OpenBSD partition found"
+ def __init__(self, device):
+ """Create a DiskLabel instance"""
- d.seek(BLOCKSIZE * self.mbr.part[self.part_num].first_sector)
- part_sector0 = d.read(BLOCKSIZE)
- # The offset of the disklabel from the begining of the
- # partition is one sector
- part_sector1 = d.read(BLOCKSIZE)
+ device.seek(BLOCKSIZE, os.SEEK_CUR)
+ # The offset of the disklabel from the beginning of the partition is
+ # one sector
+ sector1 = device.read(BLOCKSIZE)
(self.magic,
self.dtype,
self.npartitions,
self.bbsize,
self.sbsize,
- ptable_raw) = struct.unpack(self.format, part_sector1)
+ ptable_raw) = struct.unpack(self.format, sector1)
- assert self.magic == DISKMAGIC, "Disklabel is not valid"
+ assert self.magic == self.DISKMAGIC, "Disklabel is not valid"
self.ptable = self.PartitionTable(ptable_raw, self.npartitions)
return (self.bstarth << 32) + self.bstart
def setbend(self, bend):
- """Set end of useable region"""
+ """Set size of useable region"""
self.bendh = bend >> 32
self.bend = bend & 0xffffffff
def getbend(self):
+ """Get size of usable region"""
return (self.bendh << 32) + self.bend
def enlarge_disk(self, new_size):
- """Enlarge the size of the disk"""
+ """Enlarge the size of the disk and return the last usable sector"""
- assert new_size >= self.secperunit, \
- "New size cannot be smaller that %s" % self.secperunit
+ assert new_size >= self.getdsize(), \
+ "New size cannot be smaller that %s" % self.getdsize()
# Fix the disklabel
self.setdsize(new_size)
# Partition 'c' descriptes the entire disk
self.ptable.setpsize(2, new_size)
- # Fix the MBR table
- start = self.mbr.part[self.part_num].first_sector
- self.mbr.part[self.part_num].sector_count = self.getbend() - start
-
- lba = self.getbend() - 1
- cylinder = lba // (self.ntracks * self.nsectors)
- header = (lba // self.nsectors) % self.ntracks
- sector = (lba % self.nsectors) + 1
- chs = MBR.Partition.pack_chs(cylinder, header, sector)
- self.mbr.part[self.part_num].end = chs
-
+ # Update the checksum
self.checksum = self.compute_checksum()
- def write(self):
- """Write the disklabel back to the media"""
- with open(self.disk, 'rw+b') as d:
- d.write(self.mbr.pack())
+ # getbend() gives back the size of the usable region and not the end of
+ # the usable region. I named it like this because this is how it is
+ # named in OpenBSD. To get the last usable sector you need to reduce
+ # this value by one.
+ return self.getbend() - 1
+
+ def write_to(self, device):
+ """Write the disklabel to a device"""
- d.seek((self.mbr.part[self.part_num].first_sector + 1) * BLOCKSIZE)
- d.write(self.pack())
+ # The disklabel starts at sector 1
+ device.seek(BLOCKSIZE, os.SEEK_CUR)
+ device.write(self.pack())
def get_last_partition_id(self):
"""Returns the id of the last partition"""
def __str__(self):
"""Print the Disklabel"""
- title1 = "Master Boot Record"
- title2 = "Disklabel"
+ title = "Disklabel"
return \
- "%s\n%s\n%s\n" % (title1, len(title1) * "=", str(self.mbr)) + \
- "%s\n%s\n" % (title2, len(title2) * "=") + \
+ "%s\n%s\n" % (title, len(title) * "=") + \
"Magic Number: 0x%x\n" % self.magic + \
"Drive type: %d\n" % self.dtype + \
"Subtype: %d\n" % self.subtype + \
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