aif-ng/aif/disk/block_fallback.py
brent s ca1f12f5bd soooo...
turns out ALL of the disk operations can be performed with
gobject-introspection.

BUT it's unlikely that that'll be available everywhere, or that
the Arch Linux releng team would include it, etc.
So we have fallbacks to mimic it.

BUT please try to use gobject-introspection with libblockdev,
because it's going to be a lot faster and a lot less error-prone.
2019-11-01 02:54:51 -04:00

226 lines
9.6 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 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.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()