aif-ng/aif/disk/block_fallback.py
2019-11-01 03:43:14 -04:00

223 lines
9.5 KiB
Python

# To reproduce sgdisk behaviour in v1 of AIF-NG:
# https://gist.github.com/herry13/5931cac426da99820de843477e41e89e
# https://github.com/dcantrell/pyparted/blob/master/examples/query_device_capacity.py
# TODO: Remember to replicate genfstab behaviour.
import re
try:
# https://stackoverflow.com/a/34812552/733214
# https://github.com/karelzak/util-linux/blob/master/libmount/python/test_mount_context.py#L6
import libmount as mount
except ImportError:
# We should never get here. util-linux is part of core (base) in Arch and uses "libmount".
import pylibmount as mount
##
import parted # https://www.gnu.org/software/parted/api/index.html
import psutil
##
from aif.utils import xmlBool, size
# TODO: https://serverfault.com/questions/356534/ssd-erase-block-size-lvm-pv-on-raw-device-alignment
PARTED_FSTYPES = sorted(list(dict(vars(parted.filesystem))['fileSystemType'].keys()))
PARTED_FLAGS = sorted(list(parted.partition.partitionFlag.values()))
IDX_FLAG = dict(parted.partition.partitionFlag)
FLAG_IDX = {v: k for k, v in IDX_FLAG.items()}
# parted lib can do SI or IEC. So can we.
_pos_re = re.compile((r'^(?P<pos_or_neg>-|\+)?\s*'
r'(?P<size>[0-9]+)\s*'
# empty means size in sectors
r'(?P<pct_unit_or_sct>%|{0}|)\s*$'.format('|'.join(size.valid_storage))
))
def convertSizeUnit(pos):
orig_pos = pos
pos = _pos_re.search(pos)
if pos:
pos_or_neg = (pos.group('pos_or_neg') if pos.group('pos_or_neg') else None)
if pos_or_neg == '+':
from_beginning = True
elif pos_or_neg == '-':
from_beginning = False
else:
from_beginning = pos_or_neg
_size = int(pos.group('size'))
amt_type = pos.group('pct_unit_or_sct').strip()
else:
raise ValueError('Invalid size specified: {0}'.format(orig_pos))
return((from_beginning, _size, amt_type))
class Partition(object):
def __init__(self, part_xml, diskobj, start_sector, partnum, tbltype, part_type = None):
if tbltype not in ('gpt', 'msdos'):
raise ValueError('{0} must be one of gpt or msdos'.format(tbltype))
if tbltype == 'msdos' and part_type not in ('primary', 'extended', 'logical'):
raise ValueError(('You must specify if this is a '
'primary, extended, or logical partition for msdos partition tables'))
self.xml = part_xml
self.id = part_xml.attrib['id']
self.flags = set()
for f in self.xml.findall('partitionFlag'):
if f.text in PARTED_FLAGS:
self.flags.add(f.text)
self.flags = sorted(list(self.flags))
self.partnum = partnum
if tbltype == 'msdos':
if partnum > 4:
self.part_type = parted.PARTITION_LOGICAL
else:
if part_type == 'extended':
self.part_type = parted.PARTITION_EXTENDED
elif part_type == 'logical':
self.part_type = parted.PARTITION_LOGICAL
else:
self.part_type = parted.PARTITION_NORMAL
self.fstype = self.xml.attrib['fsType'].lower()
if self.fstype not in PARTED_FSTYPES:
raise ValueError(('{0} is not a valid partition filesystem type; '
'must be one of: {1}').format(self.xml.attrib['fsType'],
', '.join(sorted(PARTED_FSTYPES))))
self.disk = diskobj
self.device = self.disk.device
self.devpath = '{0}{1}'.format(self.device.path, partnum)
self.is_hiformatted = False
sizes = {}
for s in ('start', 'stop'):
x = dict(zip(('from_bgn', 'size', 'type'),
convertSizeUnit(self.xml.attrib[s])))
sectors = x['size']
if x['type'] == '%':
sectors = int(self.device.getLength() / x['size'])
else:
sectors = int(size.convertStorage(x['size'], x['type'], target = 'B') / self.device.sectorSize)
sizes[s] = (sectors, x['from_bgn'])
if sizes['start'][1] is not None:
if sizes['start'][1]:
self.begin = sizes['start'][0] + 0
else:
self.begin = self.device.getLength() - sizes['start'][0]
else:
self.begin = sizes['start'][0] + start_sector
if sizes['stop'][1] is not None:
if sizes['stop'][1]:
self.end = sizes['stop'][0] + 0
else:
# This *technically* should be - 34, at least for gpt, but the alignment optimizer fixes it for us.
self.end = (self.device.getLength() - 1) - sizes['stop'][0]
else:
self.end = self.begin + sizes['stop'][0]
# TECHNICALLY we could craft the Geometry object with "length = ...", but it doesn't let us be explicit
# in configs. So we manually crunch the numbers and do it all at the end.
self.geometry = parted.Geometry(device = self.device,
start = self.begin,
end = self.end)
self.filesystem = parted.FileSystem(type = self.fstype,
geometry = self.geometry)
self.partition = parted.Partition(disk = diskobj,
type = self.part_type,
geometry = self.geometry,
fs = self.filesystem)
for f in self.flags[:]:
flag_id = FLAG_IDX[f]
if self.partition.isFlagAvailable(flag_id):
self.partition.setFlag(flag_id)
else:
self.flags.remove(f)
if tbltype == 'gpt' and self.xml.attrib.get('name'):
# The name attribute setting is b0rk3n, so we operate on the underlying PedPartition object.
# https://github.com/dcantrell/pyparted/issues/49#issuecomment-540096687
# https://github.com/dcantrell/pyparted/issues/65
# self.partition.name = self.xml.attrib.get('name')
_pedpart = self.partition.getPedPartition()
_pedpart.set_name(self.xml.attrib.get('name'))
def detect(self):
pass
class Disk(object):
def __init__(self, disk_xml):
self.xml = disk_xml
self.devpath = self.xml.attrib['device']
self._initDisk()
def _initDisk(self):
self.tabletype = self.xml.attrib.get('diskFormat', 'gpt').lower()
if self.tabletype in ('bios', 'mbr', 'dos'):
self.tabletype = 'msdos'
validlabels = parted.getLabels()
if self.tabletype not in validlabels:
raise ValueError(('Disk format {0} is not valid for this architecture;'
'must be one of: {1}'.format(self.tabletype, ', '.join(list(validlabels)))))
self.device = parted.getDevice(self.devpath)
self.disk = parted.freshDisk(self.device, self.tabletype)
self.is_lowformatted = False
self.is_hiformatted = False
self.is_partitioned = False
self.partitions = []
return()
def diskFormat(self):
if self.is_lowformatted:
return()
# This is a safeguard. We do *not* want to low-format a disk that is mounted.
for p in psutil.disk_partitions(all = True):
if self.devpath in p:
raise RuntimeError('{0} is mounted; we are cowardly refusing to low-format it'.format(self.devpath))
self.disk.deleteAllPartitions()
self.disk.commit()
self.is_lowformatted = True
self.is_partitioned = False
return()
def getPartitions(self):
# For GPT, this *technically* should be 34 -- or, more precisely, 2048 (see FAQ in manual), but the alignment
# optimizer fixes it for us automatically.
# But for DOS tables, it's required.
if self.tabletype == 'msdos':
start_sector = 2048
else:
start_sector = 0
self.partitions = []
xml_partitions = self.xml.findall('part')
for idx, part in enumerate(xml_partitions):
partnum = idx + 1
if self.tabletype == 'gpt':
p = Partition(part, self.disk, start_sector, partnum, self.tabletype)
else:
parttype = 'primary'
if len(xml_partitions) > 4:
if partnum == 4:
parttype = 'extended'
elif partnum > 4:
parttype = 'logical'
p = Partition(part, self.disk, start_sector, partnum, self.tabletype, part_type = parttype)
start_sector = p.end + 1
self.partitions.append(p)
return()
def partFormat(self):
if self.is_partitioned:
return()
if not self.is_lowformatted:
self.diskFormat()
# This is a safeguard. We do *not* want to partition a disk that is mounted.
for p in psutil.disk_partitions(all = True):
if self.devpath in p:
raise RuntimeError('{0} is mounted; we are cowardly refusing to low-format it'.format(self.devpath))
if not self.partitions:
self.getPartitions()
if not self.partitions:
return()
for p in self.partitions:
self.disk.addPartition(partition = p, constraint = self.device.optimalAlignedConstraint)
self.disk.commit()
p.devpath = p.partition.path
p.is_hiformatted = True
self.is_partitioned = True
return()