def calculate_android_partition_size_and_offset(image_file):
"""Return the size and offset of the android partitions.
Both the size and offset are in bytes.
:param image_file: A string containing the path to the image_file.
:return: A list of (offset, size) pairs.
"""
# Here we can use parted.Device to read the partitions because we're
# reading from a regular file rather than a block device. If it was a
# block device we'd need root rights.
vfat_partition = None
disk = Disk(Device(image_file))
partition_info = []
for partition in disk.partitions:
# Will ignore any partitions before boot and of type EXTENDED
if 'boot' in partition.getFlagsAsString():
vfat_partition = partition
geometry = partition.geometry
partition_info.append(
(geometry.start * SECTOR_SIZE, geometry.length * SECTOR_SIZE))
elif (vfat_partition is not None
and partition.type != PARTITION_EXTENDED):
geometry = partition.geometry
partition_info.append(
(geometry.start * SECTOR_SIZE, geometry.length * SECTOR_SIZE))
# NB: don't use vfat_partition.nextPartition() as that might return
# a partition of type PARTITION_FREESPACE; it's much easier to
# iterate disk.partitions which only returns
# parted.PARTITION_NORMAL partitions
assert vfat_partition is not None, ("Couldn't find boot partition on %s" %
image_file)
assert len(partition_info) == 5
return partition_info
def get_default_sector_size():
with NamedTemporaryFile() as fp:
# Truncate to zero, so that extending the size in the next call
# will cause all the bytes to read as zero. Stevens $4.13
os.truncate(fp.name, 0)
os.truncate(fp.name, MiB(1))
return Device(fp.name).sectorSize
def calculate_partition_size_and_offset(image_file):
"""Return the size and offset of the boot and root partitions.
Both the size and offset are in sectors.
:param image_file: A string containing the path to the image_file.
:return: A 4-tuple containing the offset and size of the boot partition
followed by the offset and size of the root partition.
"""
# Here we can use parted.Device to read the partitions because we're
# reading from a regular file rather than a block device. If it was a
# block device we'd need root rights.
disk = Disk(Device(image_file))
vfat_partition = None
linux_partition = None
for partition in disk.partitions:
assert partition.type == PARTITION_NORMAL, (
"Parted should only return normal partitions but got type %i" %
partition.type)
if 'boot' in partition.getFlagsAsString():
geometry = partition.geometry
vfat_offset = geometry.start * SECTOR_SIZE
vfat_size = geometry.length * SECTOR_SIZE
vfat_partition = partition
elif vfat_partition is not None:
# next partition after boot partition is the root partition
# NB: don't use vfat_partition.nextPartition() as that might return
# a partition of type PARTITION_FREESPACE; it's much easier to
# iterate disk.partitions which only returns
# parted.PARTITION_NORMAL partitions
geometry = partition.geometry
linux_offset = geometry.start * SECTOR_SIZE
linux_size = geometry.length * SECTOR_SIZE
linux_partition = partition
break
assert vfat_partition is not None, ("Couldn't find boot partition on %s" %
image_file)
assert linux_partition is not None, ("Couldn't find root partition on %s" %
image_file)
return vfat_size, vfat_offset, linux_size, linux_offset