from datetime import datetime, timedelta, timezone from getpass import getuser from itertools import zip_longest import msgpack import os import socket import stat import sys import time from io import BytesIO from attic import xattr from attic.chunker import chunkify from attic.helpers import Error, uid2user, user2uid, gid2group, group2gid, \ Statistics, decode_dict, st_mtime_ns, make_path_safe ITEMS_BUFFER = 1024 * 1024 CHUNK_MIN = 1024 WINDOW_SIZE = 0xfff CHUNK_MASK = 0xffff utime_supports_fd = os.utime in getattr(os, 'supports_fd', {}) has_mtime_ns = sys.version >= '3.3' has_lchmod = hasattr(os, 'lchmod') 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_longest(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, cache, key, stats): self.buffer = BytesIO() self.packer = msgpack.Packer(unicode_errors='surrogateescape') self.cache = cache self.chunks = [] self.key = key self.stats = stats def add(self, item): self.buffer.write(self.packer.pack(item)) def flush(self, flush=False): if self.buffer.tell() == 0: return self.buffer.seek(0) chunks = list(bytes(s) for s in chunkify(self.buffer, WINDOW_SIZE, CHUNK_MASK, CHUNK_MIN, self.key.chunk_seed)) self.buffer.seek(0) self.buffer.truncate(0) # Leave the last parital chunk in the buffer unless flush is True end = None if flush or len(chunks) == 1 else -1 for chunk in chunks[:end]: id_, _, _ = self.cache.add_chunk(self.key.id_hash(chunk), chunk, self.stats) self.chunks.append(id_) if end == -1: self.buffer.write(chunks[-1]) def is_full(self): return self.buffer.tell() > self.BUFFER_SIZE class Archive: class DoesNotExist(Error): """Archive {} does not exist""" class AlreadyExists(Error): """Archive {} already exists""" def __init__(self, repository, key, manifest, name, cache=None, create=False, checkpoint_interval=300, numeric_owner=False): self.cwd = os.getcwd() self.key = key self.repository = repository self.cache = cache self.manifest = manifest self.hard_links = {} self.stats = Statistics() self.name = name self.checkpoint_interval = checkpoint_interval self.numeric_owner = numeric_owner self.items_buffer = ChunkBuffer(self.cache, self.key, self.stats) self.pipeline = DownloadPipeline(self.repository, self.key) if create: 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 not self.checkpoint_name in manifest.archives: break i += 1 else: if name not in self.manifest.archives: raise self.DoesNotExist(name) info = self.manifest.archives[name] self.load(info[b'id']) def load(self, id): self.id = id data = self.key.decrypt(self.id, self.repository.get(self.id)) self.metadata = msgpack.unpackb(data) if self.metadata[b'version'] != 1: raise Exception('Unknown archive metadata version') 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""" t, f = self.metadata[b'time'].split('.', 1) return datetime.strptime(t, '%Y-%m-%dT%H:%M:%S').replace(tzinfo=timezone.utc) + timedelta(seconds=float('.' + f)) 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(self, item): self.items_buffer.add(item) now = time.time() if now - self.last_checkpoint > self.checkpoint_interval: self.last_checkpoint = now self.write_checkpoint() if self.items_buffer.is_full(): self.items_buffer.flush() def write_checkpoint(self): self.save(self.checkpoint_name) del self.manifest.archives[self.checkpoint_name] self.cache.chunk_decref(self.id) def save(self, name=None): name = name or self.name if name in self.manifest.archives: raise self.AlreadyExists(name) self.items_buffer.flush(flush=True) metadata = { 'version': 1, 'name': name, 'items': self.items_buffer.chunks, 'cmdline': sys.argv, 'hostname': socket.gethostname(), 'username': getuser(), 'time': datetime.utcnow().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 = self.cache.chunks[id] stats.update(size, csize, count == 1) self.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_longest(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): 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: os.unlink(path) except OSError: pass mode = item[b'mode'] if stat.S_ISDIR(mode): if not os.path.exists(path): os.makedirs(path) if restore_attrs: self.restore_attrs(path, item) elif 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) 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): fd.write(data) fd.flush() self.restore_attrs(path, item, fd=fd.fileno()) 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_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) os.symlink(source, path) self.restore_attrs(path, item, symlink=True) 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') if xattrs: for k, v in xattrs.items(): xattr.setxattr(fd or path, k, v) uid = gid = None if not self.numeric_owner: uid = user2uid(item[b'user']) gid = group2gid(item[b'group']) uid = uid or item[b'uid'] gid = gid or item[b'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']) if fd and utime_supports_fd: # Python >= 3.3 os.utime(fd, None, ns=(item[b'mtime'], item[b'mtime'])) elif utime_supports_fd: # Python >= 3.3 os.utime(path, None, ns=(item[b'mtime'], item[b'mtime']), follow_symlinks=False) elif not symlink: os.utime(path, (item[b'mtime'] / 10**9, item[b'mtime'] / 10**9)) def verify_file(self, item, start, result): if not item[b'chunks']: start(item) result(item, True) else: start(item) ids = [id for id, size, csize in item[b'chunks']] try: for _ in self.pipeline.fetch_many(ids, is_preloaded=True): pass except Exception: result(item, False) return result(item, True) def delete(self, cache): unpacker = msgpack.Unpacker(use_list=False) for id_, data in zip_longest(self.metadata[b'items'], self.repository.get_many(self.metadata[b'items'])): unpacker.feed(self.key.decrypt(id_, data)) self.cache.chunk_decref(id_) for item in unpacker: if b'chunks' in item: for chunk_id, size, csize in item[b'chunks']: self.cache.chunk_decref(chunk_id) self.cache.chunk_decref(self.id) del self.manifest.archives[self.name] self.manifest.write() self.repository.commit() cache.commit() 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'mtime': st_mtime_ns(st), } if self.numeric_owner: item[b'user'] = item[b'group'] = None xattrs = xattr.get_all(path, follow_symlinks=False) if xattrs: item[b'xattrs'] = xattrs return item def process_item(self, path, st): item = {b'path': make_path_safe(path)} item.update(self.stat_attrs(st, path)) self.add_item(item) 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(item) 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(item) def process_file(self, path, st, cache): 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(item) return 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')) ids = cache.file_known_and_unchanged(path_hash, st) 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 = [cache.chunk_incref(id_, self.stats) for id_ in ids] # Only chunkify the file if needed if chunks is None: with open(path, 'rb') as fd: chunks = [] for chunk in chunkify(fd, WINDOW_SIZE, CHUNK_MASK, CHUNK_MIN, self.key.chunk_seed): chunks.append(cache.add_chunk(self.key.id_hash(chunk), chunk, self.stats)) cache.memorize_file(path_hash, st, [c[0] for c in chunks]) item = {b'path': safe_path, b'chunks': chunks} item.update(self.stat_attrs(st, path)) self.stats.nfiles += 1 self.add_item(item) @staticmethod def list_archives(repository, key, manifest, cache=None): for name, info in manifest.archives.items(): yield Archive(repository, key, manifest, name, cache=cache)