aif-ng/aif/disk.py

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# 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 os
import re
import subprocess
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 blkinfo
import parted # https://www.gnu.org/software/parted/api/index.html
import psutil
##
from .aif_util import xmlBool
# parted lib can do SI or IEC (see table to right at https://en.wikipedia.org/wiki/Binary_prefix)
# We bit-shift to do conversions:
# https://stackoverflow.com/a/12912296/733214
# https://stackoverflow.com/a/52684562/733214
_units = {'B': 0,
'kB': 7,
'MB': 17,
'GB': 27,
'TB': 37,
'KiB': 10,
'MiB': 20,
'GiB': 30,
'TiB': 40}
_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(list(_units.keys())))),
re.IGNORECASE)
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, disk_xml, diskobj, start_sector):
self.xml = disk_xml
device = diskobj.device
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(device.getLength() / x['size'])
elif x['type'] in _units.keys():
sectors = int(x['size'] << _units[x['type']] / 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 = 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:
self.end = device.getLength() - 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 = device,
start = self.begin,
end = self.end)
self.filesystem = parted.FileSystem(type = self.xml.attrib['fsType'],
)
self.partition = parted.Partition(disk = diskobj,
type = parted.PARTITION_NORMAL,
geometry = self.geometry,
fs = )
class Disk(object):
def __init__(self, disk_xml):
self.xml = disk_xml
self.devpath = self.xml.attrib['device']
self._initDisk()
def _initDisk(self):
self.device = parted.getDevice(self.devpath)
try:
self.disk = parted.newDisk(self.device)
if xmlBool(self.xml.attrib.get('forceReformat')):
self.is_lowformatted = False
self.is_hiformatted = False
else:
self.is_lowformatted = True
self.is_hiformatted = False
for d in blkinfo.BlkDiskInfo().get_disks(filters = {'group': 'disk',
'name': os.path.basename(self.devpath),
'kname': os.path.basename(self.devpath)}):
if d.get('fstype', '').strip() != '':
self.is_hiformatted = True
break
self.is_partitioned = True
except parted._ped.DiskException:
self.disk = None
self.is_lowformatted = False
self.is_hiformatted = False
self.is_partitioned = False
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()
tabletype = self.xml.attrib.get('diskFormat', 'gpt').lower()
if tabletype in ('bios', 'mbr'):
tabletype = 'msdos'
validlabels = parted.getLabels()
if tabletype not in validlabels:
raise ValueError(('Disk format {0} is not valid for this architecture;'
'must be one of: {1}'.format(tabletype, ', '.join(list(validlabels)))))
self.disk = parted.freshDisk(self.device, tabletype)
pass
self.is_lowformatted = True
self.is_partitioned = True
return()
def fsformat(self):
if self.is_hiformatted:
return()
# This is a safeguard. We do *not* want to high-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 high-format it'.format(self.devpath))
pass
return()