borg/borg/archive.py

1092 lines
44 KiB
Python

from binascii import hexlify
from datetime import datetime
from getpass import getuser
from itertools import groupby
import errno
from .logger import create_logger
logger = create_logger()
from .key import key_factory
from .remote import cache_if_remote
from multiprocessing import cpu_count
import os
import socket
import stat
import sys
import threading
import time
from io import BytesIO
from . import xattr
from .helpers import parse_timestamp, Error, uid2user, user2uid, gid2group, group2gid, format_timedelta, \
Manifest, Statistics, decode_dict, make_path_safe, StableDict, int_to_bigint, bigint_to_int, \
make_queue, TerminatedQueue, ProgressIndicatorPercent
from .platform import acl_get, acl_set
from .chunker import Chunker
from .hashindex import ChunkIndex
import msgpack
ITEMS_BUFFER = 1024 * 1024
CHUNK_MIN_EXP = 19 # 2**19 == 512kiB
CHUNK_MAX_EXP = 23 # 2**23 == 8MiB
HASH_WINDOW_SIZE = 0xfff # 4095B
HASH_MASK_BITS = 21 # results in ~2MiB chunks statistically
# defaults, use --chunker-params to override
CHUNKER_PARAMS = (CHUNK_MIN_EXP, CHUNK_MAX_EXP, HASH_MASK_BITS, HASH_WINDOW_SIZE)
# chunker params for the items metadata stream, finer granularity
ITEMS_CHUNKER_PARAMS = (12, 16, 14, HASH_WINDOW_SIZE)
has_lchmod = hasattr(os, 'lchmod')
has_lchflags = hasattr(os, 'lchflags')
class DownloadPipeline:
def __init__(self, repository, key):
self.repository = repository
self.key = key
def unpack_many(self, ids, filter=None, preload=False):
unpacker = msgpack.Unpacker(use_list=False)
for data in self.fetch_many(ids):
unpacker.feed(data)
items = [decode_dict(item, (b'path', b'source', b'user', b'group')) for item in unpacker]
if filter:
items = [item for item in items if filter(item)]
if preload:
for item in items:
if b'chunks' in item:
self.repository.preload([c[0] for c in item[b'chunks']])
for item in items:
yield item
def fetch_many(self, ids, is_preloaded=False):
for id_, data in zip(ids, self.repository.get_many(ids, is_preloaded=is_preloaded)):
yield self.key.decrypt(id_, data)
class ChunkBuffer:
BUFFER_SIZE = 1 * 1024 * 1024
def __init__(self, key, chunker_params=ITEMS_CHUNKER_PARAMS):
self.buffer = BytesIO()
self.packer = msgpack.Packer(unicode_errors='surrogateescape')
self.chunks = []
self.key = key
self.chunker = Chunker(self.key.chunk_seed, *chunker_params)
def add(self, item):
self.buffer.write(self.packer.pack(StableDict(item)))
if self.is_full():
self.flush()
def write_chunk(self, chunk):
raise NotImplementedError
def flush(self, flush=False):
if self.buffer.tell() == 0:
return
self.buffer.seek(0)
chunks = list(bytes(s) for s in self.chunker.chunkify(self.buffer))
self.buffer.seek(0)
self.buffer.truncate(0)
# Leave the last partial chunk in the buffer unless flush is True
end = None if flush or len(chunks) == 1 else -1
for chunk in chunks[:end]:
self.chunks.append(self.write_chunk(chunk))
if end == -1:
self.buffer.write(chunks[-1])
def is_full(self):
return self.buffer.tell() > self.BUFFER_SIZE
class CacheChunkBuffer(ChunkBuffer):
def __init__(self, cache, key, stats, chunker_params=ITEMS_CHUNKER_PARAMS):
super().__init__(key, chunker_params)
self.cache = cache
self.stats = stats
def write_chunk(self, chunk):
id_, _, _ = self.cache.add_chunk(self.key.id_hash(chunk), chunk, self.stats)
return id_
class ParallelProcessor:
def __init__(self, archive, ncrypters=None):
self.archive = archive
if ncrypters is None:
# note: cpu_count for 2 cores with HT is 4
# put load on all logical cores and avoid idle cores
ncrypters = cpu_count()
self.ncrypters = ncrypters
self.start_threads()
def reader(self):
while True:
elem = self.reader_queue.get()
if elem is None:
self.reader_queue.task_done()
break
item = elem
n = 0
# Only chunkify the file if needed
if b'chunks' in item and item[b'chunks'] is None:
fd, fh = item.pop(b'fd', None), -1
if fd is None:
fh = Archive._open_rb(item.pop(b'path_name'), item[b'st'])
fd = os.fdopen(fh, 'rb')
with fd:
for chunk in self.archive.chunker.chunkify(fd, fh):
# important: chunk is a memoryview - make a copy or it will
# have changed when we use it!
chunk = bytes(chunk)
self.crypter_queue.put((item, n, chunk))
n += 1
self.writer_queue.put((item, n, None, None, None, None)) # signal EOF via id == None , give number of chunks
self.reader_queue.task_done()
def crypter(self):
while True:
elem = self.crypter_queue.get()
if elem is None:
self.crypter_queue.task_done()
break
item, n, chunk = elem
size = len(chunk)
id = self.archive.key.id_hash(chunk)
seen = self.archive.cache.seen_or_announce_chunk(id, size)
if not seen:
# we have never seen this id before, so we need to process it
# TODO check if this creates duplicate IV/CTR values for AES
cchunk = self.archive.key.encrypt(chunk)
csize = len(cchunk)
else:
cchunk, csize = None, None
self.writer_queue.put((item, n, cchunk, id, size, csize))
self.crypter_queue.task_done()
def writer(self):
item_infos = {} # item path -> info dict
size_infos = {} # chunk id -> sizes
dying = False
while True:
elem = self.writer_queue.get()
if elem is None:
if not dying:
# received poison from stop_threads, start dying,
# but still do work the delayer thread might give us.
dying = True
# give poison to the delayer thread
self.delayer_queue.put(None)
self.writer_queue.task_done()
continue
else:
# we received the final poison from the dying delayer
self.writer_queue.task_done()
# we are dead now
break
item, n, cchunk, id, size, csize = elem
path = item[b'path']
info = item_infos.setdefault(path, dict(count=None, chunks=[]))
if id is None:
if n is not None: # note: n == None is a retry
# EOF signalled, n is the total count of chunks
info['count'] = n
else:
size, csize, new_chunk = self.archive.cache.add_chunk_nostats(cchunk, id, size, csize)
info['chunks'].append((n, id, new_chunk))
if csize != 0:
size_infos[id] = (size, csize)
if len(info['chunks']) == info['count']:
# we have processed all chunks or no chunks needed processing
if b'chunks' in item:
chunks = item[b'chunks']
if chunks is None:
# we want chunks, but we have no chunk id list yet, compute them
try:
chunks = self.archive.cache.postprocess_results(
size_infos, info['chunks'], self.archive.stats)
except self.archive.cache.ChunkSizeNotReady:
# we looked up a chunk id, but do not have the size info yet. retry later.
self.delayer_queue.put((item, None, None, None, None, None))
self.writer_queue.task_done()
continue
else:
# we have a chunk id list already, increase the ref counters, compute sizes
chunks = [self.archive.cache.chunk_incref(id_, self.archive.stats) for id_ in chunks]
item[b'chunks'] = chunks
path_hash = item.pop(b'path_hash', None)
if path_hash and chunks is not None: # a fs object (not stdin) and a regular file
st = item.pop(b'st', None)
self.archive.cache.memorize_file(path_hash, st, [c[0] for c in chunks])
del item_infos[path]
self.archive.stats.nfiles += 1
self.archive.add_item(item)
self.writer_queue.task_done()
def delayer(self):
# it is a pain that we need the compressed size for the chunks cache as it is not
# available for duplicate chunks until the original chunk has finished processing.
# this loop of (writer, delayer) with pipes connecting them is a hack to address
# this, but it makes thread teardown complicated. Rather get rid of csize?
while True:
elem = self.delayer_queue.get()
if elem is None:
# we received poison from dying writer thread, kill the writer, too.
self.writer_queue.put(None)
self.delayer_queue.task_done()
# we are dead now
break
time.sleep(0.001) # reschedule, avoid data circulating too fast
self.writer_queue.put(elem)
self.delayer_queue.task_done()
def start_threads(self):
def run_thread(func, name=None, daemon=False):
t = threading.Thread(target=func, name=name)
t.daemon = daemon
t.start()
return t
# max. memory usage of a queue with chunk data is about queue_len * CHUNK_MAX
queue_len = min(max(self.ncrypters, 4), 8)
self.reader_queue = make_queue('reader', queue_len * 10) # small items (no chunk data)
self.crypter_queue = make_queue('crypter', queue_len)
self.writer_queue = make_queue('writer', queue_len)
self.delayer_queue = make_queue('delay', queue_len)
self.reader_thread = run_thread(self.reader, 'reader')
self.crypter_threads = []
for i in range(self.ncrypters):
self.crypter_threads.append(run_thread(self.crypter, name='crypter-%d' % i))
self.delayer_thread = run_thread(self.delayer, name='delayer')
self.writer_thread = run_thread(self.writer, name='writer')
def wait_finish(self):
self.reader_queue.join()
self.crypter_queue.join()
self.writer_queue.join()
self.delayer_queue.join()
self.writer_queue.join()
def stop_threads(self):
count_before = threading.active_count()
# for every thread:
# put poison pill into its queue,
# wait until queue is processed (and thread has terminated itself)
# make queue unusable
self.reader_queue.put(None)
self.reader_queue.join()
self.reader_thread.join()
self.reader_queue = TerminatedQueue()
for i in range(self.ncrypters):
self.crypter_queue.put(None)
self.crypter_queue.join()
for t in self.crypter_threads:
t.join()
self.crypter_queue = TerminatedQueue()
self.writer_queue.put(None) # the writer will poison the delayer first
self.delayer_thread.join()
self.delayer_queue = TerminatedQueue()
self.writer_thread.join()
self.writer_queue = TerminatedQueue()
count_after = threading.active_count()
assert count_before - 3 - self.ncrypters == count_after
if count_after > 1:
print('They are alive!')
tl = [t.name for t in threading.enumerate()]
tl.remove('MainThread')
assert tl == []
class Archive:
class DoesNotExist(Error):
"""Archive {} does not exist"""
class AlreadyExists(Error):
"""Archive {} already exists"""
class IncompatibleFilesystemEncodingError(Error):
"""Failed to encode filename "{}" into file system encoding "{}". Consider configuring the LANG environment variable."""
def __init__(self, repository, key, manifest, name, cache=None, create=False,
checkpoint_interval=300, numeric_owner=False, progress=False,
chunker_params=CHUNKER_PARAMS,
start=datetime.now(), end=datetime.now()):
self.cwd = os.getcwd()
self.key = key
self.repository = repository
self.cache = cache
self.manifest = manifest
self.hard_links = {}
self.stats = Statistics()
self.show_progress = progress
self.name = name
self.checkpoint_interval = checkpoint_interval
self.numeric_owner = numeric_owner
self.start = start
self.end = end
self.pipeline = DownloadPipeline(self.repository, self.key)
if create:
self.pp = ParallelProcessor(self)
self.items_buffer = CacheChunkBuffer(self.cache, self.key, self.stats)
self.chunker = Chunker(self.key.chunk_seed, *chunker_params)
if name in manifest.archives:
raise self.AlreadyExists(name)
self.last_checkpoint = time.time()
i = 0
while True:
self.checkpoint_name = '%s.checkpoint%s' % (name, i and ('.%d' % i) or '')
if self.checkpoint_name not in manifest.archives:
break
i += 1
else:
self.pp = None
if name not in self.manifest.archives:
raise self.DoesNotExist(name)
info = self.manifest.archives[name]
self.load(info[b'id'])
self.zeros = b'\0' * (1 << chunker_params[1])
def close(self):
if self.pp:
self.pp.stop_threads()
def _load_meta(self, id):
data = self.key.decrypt(id, self.repository.get(id))
metadata = msgpack.unpackb(data)
if metadata[b'version'] != 1:
raise Exception('Unknown archive metadata version')
return metadata
def load(self, id):
self.id = id
self.metadata = self._load_meta(self.id)
decode_dict(self.metadata, (b'name', b'hostname', b'username', b'time'))
self.metadata[b'cmdline'] = [arg.decode('utf-8', 'surrogateescape') for arg in self.metadata[b'cmdline']]
self.name = self.metadata[b'name']
@property
def ts(self):
"""Timestamp of archive creation in UTC"""
return parse_timestamp(self.metadata[b'time'])
@property
def fpr(self):
return hexlify(self.id).decode('ascii')
@property
def duration(self):
return format_timedelta(self.end - self.start)
def __str__(self):
return '''Archive name: {0.name}
Archive fingerprint: {0.fpr}
Start time: {0.start:%c}
End time: {0.end:%c}
Duration: {0.duration}
Number of files: {0.stats.nfiles}'''.format(self)
def __repr__(self):
return 'Archive(%r)' % self.name
def iter_items(self, filter=None, preload=False):
for item in self.pipeline.unpack_many(self.metadata[b'items'], filter=filter, preload=preload):
yield item
def add_item_queued(self, item):
self.pp.reader_queue.put(item)
def add_item(self, item):
unknown_keys = set(item) - ITEM_KEYS
assert not unknown_keys, ('unknown item metadata keys detected, please update ITEM_KEYS: %s',
','.join(k.decode('ascii') for k in unknown_keys))
if self.show_progress:
self.stats.show_progress(item=item, dt=0.2)
self.items_buffer.add(item)
if time.time() - self.last_checkpoint > self.checkpoint_interval:
self.write_checkpoint()
self.last_checkpoint = time.time()
def write_checkpoint(self):
self.save(self.checkpoint_name)
del self.manifest.archives[self.checkpoint_name]
self.cache.chunk_decref(self.id, self.stats)
def save(self, name=None, timestamp=None):
self.pp.wait_finish()
name = name or self.name
if name in self.manifest.archives:
raise self.AlreadyExists(name)
self.items_buffer.flush(flush=True)
if timestamp is None:
timestamp = datetime.utcnow()
metadata = StableDict({
'version': 1,
'name': name,
'items': self.items_buffer.chunks,
'cmdline': sys.argv,
'hostname': socket.gethostname(),
'username': getuser(),
'time': timestamp.isoformat(),
})
data = msgpack.packb(metadata, unicode_errors='surrogateescape')
self.id = self.key.id_hash(data)
self.cache.add_chunk(self.id, data, self.stats)
self.manifest.archives[name] = {'id': self.id, 'time': metadata['time']}
self.manifest.write()
self.repository.commit()
self.cache.commit()
def calc_stats(self, cache):
def add(id):
count, size, csize = cache.chunks[id]
stats.update(size, csize, count == 1)
cache.chunks[id] = count - 1, size, csize
def add_file_chunks(chunks):
for id, _, _ in chunks:
add(id)
# This function is a bit evil since it abuses the cache to calculate
# the stats. The cache transaction must be rolled back afterwards
unpacker = msgpack.Unpacker(use_list=False)
cache.begin_txn()
stats = Statistics()
add(self.id)
for id, chunk in zip(self.metadata[b'items'], self.repository.get_many(self.metadata[b'items'])):
add(id)
unpacker.feed(self.key.decrypt(id, chunk))
for item in unpacker:
if b'chunks' in item:
stats.nfiles += 1
add_file_chunks(item[b'chunks'])
cache.rollback()
return stats
def extract_item(self, item, restore_attrs=True, dry_run=False, stdout=False, sparse=False):
if dry_run or stdout:
if b'chunks' in item:
for data in self.pipeline.fetch_many([c[0] for c in item[b'chunks']], is_preloaded=True):
if stdout:
sys.stdout.buffer.write(data)
if stdout:
sys.stdout.buffer.flush()
return
dest = self.cwd
if item[b'path'].startswith('/') or item[b'path'].startswith('..'):
raise Exception('Path should be relative and local')
path = os.path.join(dest, item[b'path'])
# Attempt to remove existing files, ignore errors on failure
try:
st = os.lstat(path)
if stat.S_ISDIR(st.st_mode):
os.rmdir(path)
else:
# XXX do not remove a regular file, it could be the "source"
# of a hardlink - a still empty inode that needs to be filled.
pass
except UnicodeEncodeError:
raise self.IncompatibleFilesystemEncodingError(path, sys.getfilesystemencoding()) from None
except OSError:
pass
mode = item[b'mode']
if stat.S_ISREG(mode):
if not os.path.exists(os.path.dirname(path)):
os.makedirs(os.path.dirname(path))
# Hard link?
if b'source' in item:
source = os.path.join(dest, item[b'source'])
if os.path.exists(path):
os.unlink(path)
if not os.path.exists(source):
# due to multithreaded nature and different processing time,
# the hardlink (without file content) often is in the archive
# BEFORE the "source" file (with content).
# we create an empty file that is filled with content when
# the "source" item is extracted:
with open(source, 'wb') as fd:
pass
os.link(source, path)
else:
with open(path, 'wb') as fd:
ids = [c[0] for c in item[b'chunks']]
for data in self.pipeline.fetch_many(ids, is_preloaded=True):
if sparse and self.zeros.startswith(data):
# all-zero chunk: create a hole in a sparse file
fd.seek(len(data), 1)
else:
fd.write(data)
pos = fd.tell()
fd.truncate(pos)
fd.flush()
self.restore_attrs(path, item, fd=fd.fileno())
elif stat.S_ISDIR(mode):
if not os.path.exists(path):
os.makedirs(path)
if restore_attrs:
self.restore_attrs(path, item)
elif stat.S_ISLNK(mode):
if not os.path.exists(os.path.dirname(path)):
os.makedirs(os.path.dirname(path))
source = item[b'source']
if os.path.exists(path):
os.unlink(path)
try:
os.symlink(source, path)
except UnicodeEncodeError:
raise self.IncompatibleFilesystemEncodingError(source, sys.getfilesystemencoding()) from None
self.restore_attrs(path, item, symlink=True)
elif stat.S_ISFIFO(mode):
if not os.path.exists(os.path.dirname(path)):
os.makedirs(os.path.dirname(path))
os.mkfifo(path)
self.restore_attrs(path, item)
elif stat.S_ISCHR(mode) or stat.S_ISBLK(mode):
os.mknod(path, item[b'mode'], item[b'rdev'])
self.restore_attrs(path, item)
else:
raise Exception('Unknown archive item type %r' % item[b'mode'])
def restore_attrs(self, path, item, symlink=False, fd=None):
xattrs = item.get(b'xattrs', {})
for k, v in xattrs.items():
try:
xattr.setxattr(fd or path, k, v, follow_symlinks=False)
except OSError as e:
if e.errno not in (errno.ENOTSUP, errno.EACCES, ):
# only raise if the errno is not on our ignore list:
# ENOTSUP == xattrs not supported here
# EACCES == permission denied to set this specific xattr
# (this may happen related to security.* keys)
raise
uid = gid = None
if not self.numeric_owner:
uid = user2uid(item[b'user'])
gid = group2gid(item[b'group'])
uid = item[b'uid'] if uid is None else uid
gid = item[b'gid'] if gid is None else gid
# This code is a bit of a mess due to os specific differences
try:
if fd:
os.fchown(fd, uid, gid)
else:
os.lchown(path, uid, gid)
except OSError:
pass
if fd:
os.fchmod(fd, item[b'mode'])
elif not symlink:
os.chmod(path, item[b'mode'])
elif has_lchmod: # Not available on Linux
os.lchmod(path, item[b'mode'])
mtime = bigint_to_int(item[b'mtime'])
if b'atime' in item:
atime = bigint_to_int(item[b'atime'])
else:
# old archives only had mtime in item metadata
atime = mtime
if fd:
os.utime(fd, None, ns=(atime, mtime))
else:
os.utime(path, None, ns=(atime, mtime), follow_symlinks=False)
acl_set(path, item, self.numeric_owner)
# Only available on OS X and FreeBSD
if has_lchflags and b'bsdflags' in item:
try:
os.lchflags(path, item[b'bsdflags'])
except OSError:
pass
def rename(self, name):
if name in self.manifest.archives:
raise self.AlreadyExists(name)
metadata = StableDict(self._load_meta(self.id))
metadata[b'name'] = name
data = msgpack.packb(metadata, unicode_errors='surrogateescape')
new_id = self.key.id_hash(data)
self.cache.add_chunk(new_id, data, self.stats)
self.manifest.archives[name] = {'id': new_id, 'time': metadata[b'time']}
self.cache.chunk_decref(self.id, self.stats)
del self.manifest.archives[self.name]
def delete(self, stats, progress=False):
unpacker = msgpack.Unpacker(use_list=False)
items_ids = self.metadata[b'items']
pi = ProgressIndicatorPercent(total=len(items_ids), msg="Decrementing references %3.0f%%", same_line=True)
for (i, (items_id, data)) in enumerate(zip(items_ids, self.repository.get_many(items_ids))):
if progress:
pi.show(i)
unpacker.feed(self.key.decrypt(items_id, data))
self.cache.chunk_decref(items_id, stats)
for item in unpacker:
if b'chunks' in item:
for chunk_id, size, csize in item[b'chunks']:
self.cache.chunk_decref(chunk_id, stats)
if progress:
pi.finish()
self.cache.chunk_decref(self.id, stats)
del self.manifest.archives[self.name]
def stat_attrs(self, st, path):
item = {
b'mode': st.st_mode,
b'uid': st.st_uid, b'user': uid2user(st.st_uid),
b'gid': st.st_gid, b'group': gid2group(st.st_gid),
b'atime': int_to_bigint(st.st_atime_ns),
b'ctime': int_to_bigint(st.st_ctime_ns),
b'mtime': int_to_bigint(st.st_mtime_ns),
}
if self.numeric_owner:
item[b'user'] = item[b'group'] = None
xattrs = xattr.get_all(path, follow_symlinks=False)
if xattrs:
item[b'xattrs'] = StableDict(xattrs)
if has_lchflags and st.st_flags:
item[b'bsdflags'] = st.st_flags
acl_get(path, item, st, self.numeric_owner)
return item
def process_dir(self, path, st):
item = {b'path': make_path_safe(path)}
item.update(self.stat_attrs(st, path))
self.add_item_queued(item)
return 'd' # directory
def process_fifo(self, path, st):
item = {b'path': make_path_safe(path)}
item.update(self.stat_attrs(st, path))
self.add_item_queued(item)
return 'f' # fifo
def process_dev(self, path, st):
item = {b'path': make_path_safe(path), b'rdev': st.st_rdev}
item.update(self.stat_attrs(st, path))
self.add_item_queued(item)
if stat.S_ISCHR(st.st_mode):
return 'c' # char device
elif stat.S_ISBLK(st.st_mode):
return 'b' # block device
def process_symlink(self, path, st):
source = os.readlink(path)
item = {b'path': make_path_safe(path), b'source': source}
item.update(self.stat_attrs(st, path))
self.add_item_queued(item)
return 's' # symlink
def process_stdin(self, path, cache):
uid, gid = 0, 0
t = int_to_bigint(int(time.time()) * 1000000000)
item = {
b'path': path,
b'fd': sys.stdin.buffer, # binary
b'mode': 0o100660, # regular file, ug=rw
b'uid': uid, b'user': uid2user(uid),
b'gid': gid, b'group': gid2group(gid),
b'mtime': t, b'atime': t, b'ctime': t,
}
self.add_item_queued(item)
return 'i' # stdin
def process_file(self, path, st, cache):
status = None
safe_path = make_path_safe(path)
# Is it a hard link?
if st.st_nlink > 1:
source = self.hard_links.get((st.st_ino, st.st_dev))
if (st.st_ino, st.st_dev) in self.hard_links:
item = self.stat_attrs(st, path)
item.update({b'path': safe_path, b'source': source})
self.add_item_queued(item)
status = 'h' # regular file, hardlink (to already seen inodes)
return status
else:
self.hard_links[st.st_ino, st.st_dev] = safe_path
path_hash = self.key.id_hash(os.path.join(self.cwd, path).encode('utf-8', 'surrogateescape'))
first_run = not cache.files
ids = cache.file_known_and_unchanged(path_hash, st)
if first_run:
logger.info('processing files')
chunks = None
if ids is not None:
# Make sure all ids are available
for id_ in ids:
if not cache.seen_chunk(id_):
break
else:
chunks = ids
status = 'U' # regular file, unchanged
else:
status = 'A' # regular file, added
if chunks is None:
status = status or 'M' # regular file, modified (if not 'A' already)
item = {
b'path': safe_path,
b'path_name': path,
b'path_hash': path_hash,
b'chunks': chunks,
b'st': st,
}
item.update(self.stat_attrs(st, path))
self.add_item_queued(item)
return status
@staticmethod
def list_archives(repository, key, manifest, cache=None):
# expensive! see also Manifest.list_archive_infos.
for name, info in manifest.archives.items():
yield Archive(repository, key, manifest, name, cache=cache)
@staticmethod
def _open_rb(path, st):
flags_normal = os.O_RDONLY | getattr(os, 'O_BINARY', 0)
flags_noatime = flags_normal | getattr(os, 'O_NOATIME', 0)
euid = None
def open_simple(p, s):
return os.open(p, flags_normal)
def open_noatime(p, s):
return os.open(p, flags_noatime)
def open_noatime_if_owner(p, s):
if euid == 0 or s.st_uid == euid:
# we are root or owner of file
return open_noatime(p, s)
else:
return open_simple(p, s)
def open_noatime_with_fallback(p, s):
try:
fd = os.open(p, flags_noatime)
except PermissionError:
# Was this EPERM due to the O_NOATIME flag?
fd = os.open(p, flags_normal)
# Yes, it was -- otherwise the above line would have thrown
# another exception.
nonlocal euid
euid = os.geteuid()
# So in future, let's check whether the file is owned by us
# before attempting to use O_NOATIME.
Archive._open_rb = open_noatime_if_owner
return fd
if flags_noatime != flags_normal:
# Always use O_NOATIME version.
Archive._open_rb = open_noatime_with_fallback
else:
# Always use non-O_NOATIME version.
Archive._open_rb = open_simple
return Archive._open_rb(path, st)
# this set must be kept complete, otherwise the RobustUnpacker might malfunction:
ITEM_KEYS = set([b'path', b'source', b'rdev', b'chunks',
b'mode', b'user', b'group', b'uid', b'gid', b'mtime', b'atime', b'ctime',
b'xattrs', b'bsdflags', b'acl_nfs4', b'acl_access', b'acl_default', b'acl_extended', ])
class RobustUnpacker:
"""A restartable/robust version of the streaming msgpack unpacker
"""
def __init__(self, validator):
super().__init__()
self.item_keys = [msgpack.packb(name) for name in ITEM_KEYS]
self.validator = validator
self._buffered_data = []
self._resync = False
self._unpacker = msgpack.Unpacker(object_hook=StableDict)
def resync(self):
self._buffered_data = []
self._resync = True
def feed(self, data):
if self._resync:
self._buffered_data.append(data)
else:
self._unpacker.feed(data)
def __iter__(self):
return self
def __next__(self):
if self._resync:
data = b''.join(self._buffered_data)
while self._resync:
if not data:
raise StopIteration
# Abort early if the data does not look like a serialized dict
if len(data) < 2 or ((data[0] & 0xf0) != 0x80) or ((data[1] & 0xe0) != 0xa0):
data = data[1:]
continue
# Make sure it looks like an item dict
for pattern in self.item_keys:
if data[1:].startswith(pattern):
break
else:
data = data[1:]
continue
self._unpacker = msgpack.Unpacker(object_hook=StableDict)
self._unpacker.feed(data)
try:
item = next(self._unpacker)
if self.validator(item):
self._resync = False
return item
# Ignore exceptions that might be raised when feeding
# msgpack with invalid data
except (TypeError, ValueError, StopIteration):
pass
data = data[1:]
else:
return next(self._unpacker)
class ArchiveChecker:
def __init__(self):
self.error_found = False
self.possibly_superseded = set()
def check(self, repository, repair=False, archive=None, last=None, prefix=None, save_space=False):
logger.info('Starting archive consistency check...')
self.check_all = archive is None and last is None and prefix is None
self.repair = repair
self.repository = repository
self.init_chunks()
self.key = self.identify_key(repository)
if Manifest.MANIFEST_ID not in self.chunks:
logger.error("Repository manifest not found!")
self.error_found = True
self.manifest = self.rebuild_manifest()
else:
self.manifest, _ = Manifest.load(repository, key=self.key)
self.rebuild_refcounts(archive=archive, last=last, prefix=prefix)
self.orphan_chunks_check()
self.finish(save_space=save_space)
if self.error_found:
logger.error('Archive consistency check complete, problems found.')
else:
logger.info('Archive consistency check complete, no problems found.')
return self.repair or not self.error_found
def init_chunks(self):
"""Fetch a list of all object keys from repository
"""
# Explicitly set the initial hash table capacity to avoid performance issues
# due to hash table "resonance"
capacity = int(len(self.repository) * 1.2)
self.chunks = ChunkIndex(capacity)
marker = None
while True:
result = self.repository.list(limit=10000, marker=marker)
if not result:
break
marker = result[-1]
for id_ in result:
self.chunks[id_] = (0, 0, 0)
def identify_key(self, repository):
cdata = repository.get(next(self.chunks.iteritems())[0])
return key_factory(repository, cdata)
def rebuild_manifest(self):
"""Rebuild the manifest object if it is missing
Iterates through all objects in the repository looking for archive metadata blocks.
"""
logger.info('Rebuilding missing manifest, this might take some time...')
manifest = Manifest(self.key, self.repository)
for chunk_id, _ in self.chunks.iteritems():
cdata = self.repository.get(chunk_id)
data = self.key.decrypt(chunk_id, cdata)
# Some basic sanity checks of the payload before feeding it into msgpack
if len(data) < 2 or ((data[0] & 0xf0) != 0x80) or ((data[1] & 0xe0) != 0xa0):
continue
if b'cmdline' not in data or b'\xa7version\x01' not in data:
continue
try:
archive = msgpack.unpackb(data)
# Ignore exceptions that might be raised when feeding
# msgpack with invalid data
except (TypeError, ValueError, StopIteration):
continue
if isinstance(archive, dict) and b'items' in archive and b'cmdline' in archive:
logger.info('Found archive %s', archive[b'name'].decode('utf-8'))
manifest.archives[archive[b'name'].decode('utf-8')] = {b'id': chunk_id, b'time': archive[b'time']}
logger.info('Manifest rebuild complete.')
return manifest
def rebuild_refcounts(self, archive=None, last=None, prefix=None):
"""Rebuild object reference counts by walking the metadata
Missing and/or incorrect data is repaired when detected
"""
# Exclude the manifest from chunks
del self.chunks[Manifest.MANIFEST_ID]
def mark_as_possibly_superseded(id_):
if self.chunks.get(id_, (0,))[0] == 0:
self.possibly_superseded.add(id_)
def add_callback(chunk):
id_ = self.key.id_hash(chunk)
cdata = self.key.encrypt(chunk)
add_reference(id_, len(chunk), len(cdata), cdata)
return id_
def add_reference(id_, size, csize, cdata=None):
try:
count, _, _ = self.chunks[id_]
self.chunks[id_] = count + 1, size, csize
except KeyError:
assert cdata is not None
self.chunks[id_] = 1, size, csize
if self.repair:
self.repository.put(id_, cdata)
def verify_file_chunks(item):
"""Verifies that all file chunks are present
Missing file chunks will be replaced with new chunks of the same
length containing all zeros.
"""
offset = 0
chunk_list = []
for chunk_id, size, csize in item[b'chunks']:
if chunk_id not in self.chunks:
# If a file chunk is missing, create an all empty replacement chunk
logger.error('{}: Missing file chunk detected (Byte {}-{})'.format(item[b'path'].decode('utf-8', 'surrogateescape'), offset, offset + size))
self.error_found = True
data = bytes(size)
chunk_id = self.key.id_hash(data)
cdata = self.key.encrypt(data)
csize = len(cdata)
add_reference(chunk_id, size, csize, cdata)
else:
add_reference(chunk_id, size, csize)
chunk_list.append((chunk_id, size, csize))
offset += size
item[b'chunks'] = chunk_list
def robust_iterator(archive):
"""Iterates through all archive items
Missing item chunks will be skipped and the msgpack stream will be restarted
"""
unpacker = RobustUnpacker(lambda item: isinstance(item, dict) and b'path' in item)
_state = 0
def missing_chunk_detector(chunk_id):
nonlocal _state
if _state % 2 != int(chunk_id not in self.chunks):
_state += 1
return _state
def report(msg, chunk_id, chunk_no):
cid = hexlify(chunk_id).decode('ascii')
msg += ' [chunk: %06d_%s]' % (chunk_no, cid) # see debug-dump-archive-items
self.error_found = True
logger.error(msg)
i = 0
for state, items in groupby(archive[b'items'], missing_chunk_detector):
items = list(items)
if state % 2:
for chunk_id in items:
report('item metadata chunk missing', chunk_id, i)
i += 1
continue
if state > 0:
unpacker.resync()
for chunk_id, cdata in zip(items, repository.get_many(items)):
unpacker.feed(self.key.decrypt(chunk_id, cdata))
try:
for item in unpacker:
if isinstance(item, dict):
yield item
else:
report('Did not get expected metadata dict when unpacking item metadata', chunk_id, i)
except Exception:
report('Exception while unpacking item metadata', chunk_id, i)
raise
i += 1
if archive is None:
# we need last N or all archives
archive_items = sorted(self.manifest.archives.items(), reverse=True,
key=lambda name_info: name_info[1][b'time'])
if prefix is not None:
archive_items = [item for item in archive_items if item[0].startswith(prefix)]
num_archives = len(archive_items)
end = None if last is None else min(num_archives, last)
else:
# we only want one specific archive
archive_items = [item for item in self.manifest.archives.items() if item[0] == archive]
num_archives = 1
end = 1
with cache_if_remote(self.repository) as repository:
for i, (name, info) in enumerate(archive_items[:end]):
logger.info('Analyzing archive {} ({}/{})'.format(name, num_archives - i, num_archives))
archive_id = info[b'id']
if archive_id not in self.chunks:
logger.error('Archive metadata block is missing!')
self.error_found = True
del self.manifest.archives[name]
continue
mark_as_possibly_superseded(archive_id)
cdata = self.repository.get(archive_id)
data = self.key.decrypt(archive_id, cdata)
archive = StableDict(msgpack.unpackb(data))
if archive[b'version'] != 1:
raise Exception('Unknown archive metadata version')
decode_dict(archive, (b'name', b'hostname', b'username', b'time'))
archive[b'cmdline'] = [arg.decode('utf-8', 'surrogateescape') for arg in archive[b'cmdline']]
items_buffer = ChunkBuffer(self.key)
items_buffer.write_chunk = add_callback
for item in robust_iterator(archive):
if b'chunks' in item:
verify_file_chunks(item)
items_buffer.add(item)
items_buffer.flush(flush=True)
for previous_item_id in archive[b'items']:
mark_as_possibly_superseded(previous_item_id)
archive[b'items'] = items_buffer.chunks
data = msgpack.packb(archive, unicode_errors='surrogateescape')
new_archive_id = self.key.id_hash(data)
cdata = self.key.encrypt(data)
add_reference(new_archive_id, len(data), len(cdata), cdata)
info[b'id'] = new_archive_id
def orphan_chunks_check(self):
if self.check_all:
unused = set()
for id_, (count, size, csize) in self.chunks.iteritems():
if count == 0:
unused.add(id_)
orphaned = unused - self.possibly_superseded
if orphaned:
logger.error('{} orphaned objects found!'.format(len(orphaned)))
self.error_found = True
if self.repair:
for id_ in unused:
self.repository.delete(id_)
else:
logger.warning('Orphaned objects check skipped (needs all archives checked).')
def finish(self, save_space=False):
if self.repair:
self.manifest.write()
self.repository.commit(save_space=save_space)