Synchronize GRUB across multiple disks. https://r00t2.io/
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bootsync/bootsync.py

324 lines
15 KiB

#!/usr/bin/env python3
import argparse
import hashlib
import json
import os
import platform
import re
import shutil
import subprocess
##
import magic # From http://darwinsys.com/file/, not https://github.com/ahupp/python-magic
import psutil
from lxml import etree
class BootSync(object):
def __init__(self, cfg = None, validate = True, dryrun = False, *args, **kwargs):
if not cfg:
self.cfgfile = '/etc/bootsync.xml'
else:
self.cfgfile = os.path.abspath(os.path.expanduser(cfg))
self.ns = None
self.cfg = None
self.xml = None
self.schema = None
# This is the current live kernel.
self.currentKernVer = self._getRunningKernel()
# This is the installed kernel from the package manager.
self.kernelFile = None
self.installedKernVer = None
self.RequireReboot = False # If a reboot is needed (WARN, don't execute!)
self.blkids = {}
self.dummy_uuid = None
self.syncs = {}
##
self.getCfg(validate = validate)
self.chkMounts(dryrun = dryrun)
self.chkReboot()
self.getChecks()
self.getBlkids()
def getCfg(self, validate = True):
if not os.path.isfile(self.cfgfile):
raise FileNotFoundError('Configuration file {0} does not exist!'.format(self.cfgfile))
try:
with open(self.cfgfile, 'rb') as f:
self.xml = etree.parse(f)
self.xml.xinclude()
self.cfg = self.xml.getroot()
except etree.XMLSyntaxError:
# self.logger.error('{0} is invalid XML'.format(self.cfgfile))
raise ValueError(('{0} does not seem to be valid XML. '
'See sample.config.xml for an example configuration.').format(self.cfgfile))
self.ns = self.cfg.nsmap.get(None, 'http://git.square-r00t.net/BootSync/')
self.ns = '{{{0}}}'.format(self.ns)
if validate:
if not self.schema:
from urllib.request import urlopen
xsi = self.cfg.nsmap.get('xsi', 'http://www.w3.org/2001/XMLSchema-instance')
schemaLocation = '{{{0}}}schemaLocation'.format(xsi)
schemaURL = self.cfg.attrib.get(schemaLocation,
('https://git.square-r00t.net/BootSync/plain/bootsync.xsd'))
with urlopen(schemaURL) as url:
self.schema = url.read()
self.schema = etree.XMLSchema(etree.XML(self.schema))
self.schema.assertValid(self.xml)
return(None)
def chkMounts(self, dryrun = False):
if not dryrun:
if os.geteuid() != 0:
raise PermissionError('You must be root to write to the appropriate destinations')
_mounts = {m.device: m.mountpoint for m in psutil.disk_partitions(all = True)}
for esp in self.cfg.findall('{0}partitions/{0}part'.format(self.ns)):
disk = esp.attrib['path']
mount = os.path.abspath(os.path.expanduser(esp.attrib['mount']))
if not dryrun:
if not os.path.isdir(mount):
os.makedirs(mount, exist_ok = True)
if disk not in _mounts:
with open(os.devnull, 'w') as devnull:
c = subprocess.run(['/usr/bin/mount', mount],
stderr = devnull)
if c.returncode == 1: # Not specified in fstab
subprocess.run(['/usr/bin/mount', disk, mount],
stderr = devnull)
elif c.returncode == 32: # Already mounted
pass
return(None)
def chkReboot(self):
self._getInstalledKernel()
if not self.kernelFile:
return() # No 'isKernel="true"' attribute was specified in the config.
if self.installedKernVer != self.currentKernVer:
self.RequireReboot = True
# TODO: logger instead?
print(('NOTE: REBOOT REQUIRED. '
'New kernel is {0}. '
'Running kernel is {1}.').format(self.installedKernVer,
self.currentKernVer))
return(None)
def getBlkids(self):
cmd = ['/usr/bin/blkid',
'-o', 'export']
if os.geteuid() != 0:
# TODO: logger?
print(('sudo is required to get device information. '
'You may be prompted to enter your sudo password.'))
cmd.insert(0, 'sudo')
c = subprocess.run(cmd,
stdout = subprocess.PIPE)
if c.returncode != 0:
raise RuntimeError('Could not fetch block ID information')
for p in c.stdout.decode('utf-8').split('\n\n'):
line = [i.strip() for i in p.splitlines()]
d = dict(map(lambda i: i.split('='), line))
if d.get('TYPE') == 'squashfs':
continue
try:
self.blkids[d['DEVNAME']] = d.get('UUID', d['PARTUUID'])
except KeyError:
try:
self.blkids[d['DEVNAME']] = d['UUID']
except KeyError:
continue
cmd = ['/usr/bin/findmnt',
'--json',
'-T', '/boot']
c = subprocess.run(cmd,
stdout = subprocess.PIPE)
self.dummy_uuid = self.blkids[json.loads(c.stdout.decode('utf-8'))['filesystems'][0]['source']]
return(None)
def getChecks(self):
# Get the default hashtype (if one exists)
fc = self.cfg.find('{0}fileChecks'.format(self.ns))
default_hashtype = fc.attrib.get('hashtype', 'md5').lower()
for f in fc.findall('{0}file'.format(self.ns)):
# We do /boot files manually in case it isn't specified as a
# separate mount.
file_hashtype = f.attrib.get('hashtype', default_hashtype).lower()
rel_fpath = f.text
fpath = os.path.join('/boot', rel_fpath)
canon_hash = self._get_hash(fpath, file_hashtype)
for esp in self.cfg.findall('{0}partitions/{0}part'.format(self.ns)):
mount = os.path.abspath(os.path.expanduser(esp.attrib['mount']))
new_fpath = os.path.join(mount, rel_fpath)
file_hash = self._get_hash(new_fpath, file_hashtype)
if not file_hashtype or file_hash != canon_hash or not file_hash:
if rel_fpath not in self.syncs:
self.syncs[rel_fpath] = []
self.syncs[rel_fpath].append(mount)
return(None)
def sync(self, dryrun = False, *args, **kwargs):
if not dryrun:
if os.geteuid() != 0:
raise PermissionError('You must be root to write to the appropriate destinations')
# fileChecks are a *lot* easier.
for rel_fpath, mounts in self.syncs.items():
for bootdir in mounts:
source = os.path.join('/boot', rel_fpath)
target = os.path.join(bootdir, rel_fpath)
destdir = os.path.dirname(target)
if not dryrun:
os.makedirs(destdir, exist_ok = True)
shutil.copy2(source, target)
bootmounts = [e.attrib['mount'] for e in self.cfg.findall('{0}partitions/{0}part'.format(self.ns))]
# syncPaths
syncpaths = self.cfg.find('{0}syncPaths'.format(self.ns))
default_hashtype = syncpaths.attrib.get('hashtype', 'md5').lower()
for syncpath in syncpaths.findall('{0}path'.format(self.ns)):
source = os.path.abspath(os.path.expanduser(syncpath.attrib['source']))
target = syncpath.attrib['target']
pattern = syncpath.attrib['pattern']
file_hashtype = syncpath.attrib.get('hashtype', default_hashtype)
# We don't use filecmp for this because:
# - dircmp doesn't recurse
# - the reports/lists don't retain relative paths
# - we can't regex out files
for root, dirs, files in os.walk(source):
prefix = re.sub(r'/?{0}/?'.format(source), '', root)
ptrn = re.compile(pattern)
for f in files:
fname_path = os.path.join(prefix, f)
bootsource = os.path.join(source, fname_path)
boottarget = os.path.join(target, fname_path)
if ptrn.search(f):
# Compare the contents.
orig_hash = self._get_hash(bootsource, file_hashtype)
for bootdir in bootmounts:
bootfile = os.path.join(bootdir, boottarget)
if not dryrun:
if not os.path.isfile(bootfile):
os.makedirs(os.path.dirname(bootfile),
exist_ok = True)
shutil.copy2(bootsource, bootfile)
else:
dest_hash = self._get_hash(bootfile, file_hashtype)
if not file_hashtype or orig_hash != dest_hash:
shutil.copy2(bootsource, bootfile)
return()
def writeConfs(self, dryrun = False, *args, **kwargs):
if not dryrun:
if os.geteuid() != 0:
raise PermissionError('You must be root to write to the appropriate destinations')
else:
return()
# Get a fresh config in place.
with open(os.devnull, 'wb') as DEVNULL:
c = subprocess.run(['/usr/bin/grub-mkconfig',
'-o', '/boot/grub/grub.cfg'],
stdout = DEVNULL,
stderr = DEVNULL)
if c.returncode != 0:
raise RuntimeError('An error occurred when generating the GRUB configuration file.')
with open('/boot/grub/grub.cfg', 'r') as f:
_grubcfg = f.read()
for esp in self.cfg.findall('{0}partitions/{0}part'.format(self.ns)):
mount = os.path.abspath(os.path.expanduser(esp.attrib['mount']))
disk = os.path.abspath(os.path.expanduser(esp.attrib['path']))
with open(os.path.join(mount, 'grub/grub.cfg'), 'w') as f:
for line in _grubcfg.splitlines():
# If the array is in a degraded state, this will still let us at LEAST boot.
line = re.sub(r'\s+--hint=[\'"]?mduuid/[a-f0-9]{32}[\'"]?', '', line)
line = re.sub(r'^(\s*set\s+root=){0}$'.format(self.dummy_uuid),
r'\g<1>{0}'.format(self.blkids[disk]),
line)
line = re.sub(r'(?<!\=UUID\=){0}'.format(self.dummy_uuid),
self.blkids[disk],
line)
line = re.sub(r'(^\s*|\s+)/boot', r'\g<1>', line)
f.write('{0}\n'.format(line))
return()
def _get_hash(self, fpathname, hashtype):
if hashtype.lower() == 'false':
return (None)
if not os.path.isfile(fpathname):
return(None)
if hashtype not in hashlib.algorithms_available:
raise ValueError('Hashtype {0} is not supported on this system'.format(hashtype))
hasher = getattr(hashlib, hashtype)
fpathname = os.path.abspath(os.path.expanduser(fpathname))
_hash = hasher()
with open(fpathname, 'rb') as fh:
_hash.update(fh.read())
return(_hash.hexdigest())
def _getRunningKernel(self):
_vers = []
# If we change the version string capture in get_file_kernel_ver(),
# this will need to be expanded as well.
# Really we only need to pick one, but #YOLO; why not sanity-check.
# ALL of these should match, hence the reduction with set() down to (what SHOULD be) just 1 item.
_vers.append(os.uname().release)
_vers.append(platform.release())
_vers.append(platform.uname().release)
_vers = sorted(list(set(_vers)))
if len(_vers) != 1:
raise RuntimeError('Cannot reliably determine current running kernel version!')
else:
return(_vers[0])
def _getInstalledKernel(self):
# Could we maybe remove the dependency for the "magic" module with a struct?
# http://lxr.linux.no/#linux+v2.6.39/Documentation/x86/boot.txt
# https://stackoverflow.com/a/11179559/733214
try:
len(self.cfg)
except TypeError:
raise RuntimeError('Tried to find the isKernel with no config set up and parsed')
for f in self.cfg.findall('{0}fileChecks/{0}file'.format(self.ns)):
isKernel = (True
if f.attrib.get('isKernel', 'false').lower() in ('true', '1')
else
False)
if isKernel:
self.kernelFile = f.text
if self.kernelFile:
with open(os.path.join('/boot', self.kernelFile), 'rb') as fh:
magicname = magic.detect_from_content(fh.read())
names = [i.strip().split(None, 1) for i in magicname.name.split(',') if i.strip() != '']
for n in names:
if len(n) != 2:
continue
k, v = n
# Note: this only grabs the version number.
# If we want to get e.g. the build user/machine, date, etc.,
# then we need to do a join. Shouldn't be necessary, though.
if k.lower() == 'version':
self.installedKernVer = v.split(None, 1)[0]
return()
def parseArgs():
args = argparse.ArgumentParser(description = ('Sync files to assist using mdadm RAID arrays with UEFI'))
args.add_argument('-V', '--no-validate',
dest = 'validate',
action = 'store_false',
help = ('If specified, do not attempt to validate the configuration file (-c/--cfg) against'
'its schema (otherwise it is fetched dynamically and requires network connection)'))
args.add_argument('-c', '--cfg',
dest = 'cfg',
default = '/etc/bootsync.xml',
help = ('The path to the bootsync configuration file. Default is /etc/bootsync.xml'))
args.add_argument('-n', '--dry-run',
dest = 'dryrun',
action = 'store_true',
help = ('If specified, don\'t write any changes'))
return(args)
def main():
args = vars(parseArgs().parse_args())
bs = BootSync(**args)
bs.sync(**args)
bs.writeConfs(**args)
return()
if __name__ == '__main__':
main()