UnknownSec Bypass 403

: /lib/python3/dist-packages/DistUpgrade/ [ drwxr-xr-x ]
name : apt_btrfs_snapshot.py # Copyright (C) 2011 Canonical # # Author: # Michael Vogt # # This program is free software; you can redistribute it and/or modify it under # the terms of the GNU General Public License as published by the Free Software # Foundation; version 3. # # This program is distributed in the hope that it will be useful, but WITHOUT # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS # FOR A PARTICULAR PURPOSE. See the GNU General Public License for more # details. # # You should have received a copy of the GNU General Public License along with # this program; if not, write to the Free Software Foundation, Inc., # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA from __future__ import print_function, unicode_literals import datetime import os import subprocess import sys import time import tempfile from distutils.spawn import find_executable from gettext import gettext as _ class AptBtrfsSnapshotError(Exception): pass class AptBtrfsNotSupportedError(AptBtrfsSnapshotError): pass class AptBtrfsRootWithNoatimeError(AptBtrfsSnapshotError): pass class FstabEntry(object): """ a single fstab entry line """ @classmethod def from_line(cls, line): # split up args = line.partition("#")[0].split() # use only the first 7 args and ignore anything after them, mount # seems to do the same, see bug #873411 comment #7 return FstabEntry(*args[0:6]) def __init__(self, fs_spec, mountpoint, fstype, options, dump=0, passno=0): # uuid or device self.fs_spec = fs_spec self.mountpoint = mountpoint self.fstype = fstype self.options = options self.dump = dump self.passno = passno def __repr__(self): return "<FstabEntry '%s' '%s' '%s' '%s' '%s' '%s'>" % ( self.fs_spec, self.mountpoint, self.fstype, self.options, self.dump, self.passno) class Fstab(list): """ a list of FstabEntry items """ def __init__(self, fstab="/etc/fstab"): super(Fstab, self).__init__() with open(fstab) as fstab_file: for line in (l.strip() for l in fstab_file): if line == "" or line.startswith("#"): continue try: entry = FstabEntry.from_line(line) except ValueError: continue self.append(entry) class LowLevelCommands(object): """ lowlevel commands invoked to perform various tasks like interact with mount and btrfs tools """ def mount(self, fs_spec, mountpoint): ret = subprocess.call(["mount", fs_spec, mountpoint]) return ret == 0 def umount(self, mountpoint): ret = subprocess.call(["umount", mountpoint]) return ret == 0 def btrfs_subvolume_snapshot(self, source, dest): ret = subprocess.call(["btrfs", "subvolume", "snapshot", source, dest]) return ret == 0 def btrfs_delete_snapshot(self, snapshot): ret = subprocess.call(["btrfs", "subvolume", "delete", snapshot]) return ret == 0 class AptBtrfsSnapshot(object): """ the high level object that interacts with the snapshot system """ # normal snapshot SNAP_PREFIX = "@apt-snapshot-" # backname when changing BACKUP_PREFIX = SNAP_PREFIX + "old-root-" def __init__(self, fstab="/etc/fstab"): self.fstab = Fstab(fstab) self.commands = LowLevelCommands() self._btrfs_root_mountpoint = None def snapshots_supported(self): """ verify that the system supports apt btrfs snapshots by checking if the right fs layout is used etc """ if not (find_executable("btrfs")): return False # check the fstab entry = self._get_supported_btrfs_root_fstab_entry() return entry is not None def _get_supported_btrfs_root_fstab_entry(self): """ return the supported btrfs root FstabEntry or None """ for entry in self.fstab: if ( entry.mountpoint == "/" and entry.fstype == "btrfs" and "subvol=@" in entry.options): return entry return None def _uuid_for_mountpoint(self, mountpoint, fstab="/etc/fstab"): """ return the device or UUID for the given mountpoint """ for entry in self.fstab: if entry.mountpoint == mountpoint: return entry.fs_spec return None def mount_btrfs_root_volume(self): uuid = self._uuid_for_mountpoint("/") mountpoint = tempfile.mkdtemp(prefix="apt-btrfs-snapshot-mp-") if not self.commands.mount(uuid, mountpoint): return None self._btrfs_root_mountpoint = mountpoint return self._btrfs_root_mountpoint def umount_btrfs_root_volume(self): res = self.commands.umount(self._btrfs_root_mountpoint) os.rmdir(self._btrfs_root_mountpoint) self._btrfs_root_mountpoint = None return res def _get_now_str(self): return datetime.datetime.now().replace(microsecond=0).isoformat( str('_')) def create_btrfs_root_snapshot(self, additional_prefix=""): mp = self.mount_btrfs_root_volume() snap_id = self._get_now_str() source = os.path.join(mp, "@") target = os.path.join(mp, self.SNAP_PREFIX + additional_prefix + snap_id) if os.path.exists(target): print(_("INFO: snapshot directory '%s' already exists, " "not creating duplicate") % (target,)) return True else: res = self.commands.btrfs_subvolume_snapshot(source, target) self.umount_btrfs_root_volume() return res def get_btrfs_root_snapshots_list(self, older_than=0): """ get the list of available snapshot If "older_then" is given (in unixtime format) it will only include snapshots that are older then the given date) """ result = [] # if older_than is used, ensure that the rootfs does not use # "noatime" if older_than != 0: entry = self._get_supported_btrfs_root_fstab_entry() if not entry: raise AptBtrfsNotSupportedError() if "noatime" in entry.options: raise AptBtrfsRootWithNoatimeError() # if there is no older than, interpret that as "now" if older_than == 0: older_than = time.time() mp = self.mount_btrfs_root_volume() for e in os.listdir(mp): if e.startswith(self.SNAP_PREFIX): # fstab is read when it was booted and when a snapshot is # created (to check if there is support for btrfs) atime = os.path.getatime(os.path.join(mp, e, "etc", "fstab")) if atime < older_than: result.append(e) self.umount_btrfs_root_volume() return result def print_btrfs_root_snapshots(self): print("Available snapshots:") print(" \n".join(self.get_btrfs_root_snapshots_list())) return True def _parse_older_than_to_unixtime(self, timefmt): now = time.time() if not timefmt.endswith("d"): raise Exception("Please specify time in days (e.g. 10d)") days = int(timefmt[:-1]) return now - (days * 24 * 60 * 60) def print_btrfs_root_snapshots_older_than(self, timefmt): older_than_unixtime = self._parse_older_than_to_unixtime(timefmt) try: print("Available snapshots older than '%s':" % timefmt) print(" \n".join(self.get_btrfs_root_snapshots_list( older_than=older_than_unixtime))) except AptBtrfsRootWithNoatimeError: sys.stderr.write("Error: fstab option 'noatime' incompatible " "with option") return False return True def clean_btrfs_root_snapshots_older_than(self, timefmt): res = True older_than_unixtime = self._parse_older_than_to_unixtime(timefmt) try: for snap in self.get_btrfs_root_snapshots_list( older_than=older_than_unixtime): res &= self.delete_snapshot(snap) except AptBtrfsRootWithNoatimeError: sys.stderr.write("Error: fstab option 'noatime' incompatible with " "option") return False return res def command_set_default(self, snapshot_name): res = self.set_default(snapshot_name) return res def set_default(self, snapshot_name, backup=True): """ set new default """ mp = self.mount_btrfs_root_volume() new_root = os.path.join(mp, snapshot_name) if ( os.path.isdir(new_root) and snapshot_name.startswith("@") and snapshot_name != "@"): default_root = os.path.join(mp, "@") backup = os.path.join(mp, self.BACKUP_PREFIX + self._get_now_str()) os.rename(default_root, backup) os.rename(new_root, default_root) print("Default changed to %s, please reboot for changes to take " "effect." % snapshot_name) else: print("You have selected an invalid snapshot. Please make sure " "that it exists, and that it is not \"@\".") self.umount_btrfs_root_volume() return True def delete_snapshot(self, snapshot_name): mp = self.mount_btrfs_root_volume() res = self.commands.btrfs_delete_snapshot( os.path.join(mp, snapshot_name)) self.umount_btrfs_root_volume() return res