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remote.py
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remote.py
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import errno
import fcntl
import logging
import os
import select
import shlex
from subprocess import Popen, PIPE
import sys
import tempfile
from . import __version__
from .helpers import Error, IntegrityError, sysinfo
from .helpers import replace_placeholders
from .repository import Repository
import msgpack
RPC_PROTOCOL_VERSION = 2
BUFSIZE = 10 * 1024 * 1024
MAX_INFLIGHT = 100
class ConnectionClosed(Error):
"""Connection closed by remote host"""
class ConnectionClosedWithHint(ConnectionClosed):
"""Connection closed by remote host. {}"""
class PathNotAllowed(Error):
"""Repository path not allowed"""
class InvalidRPCMethod(Error):
"""RPC method {} is not valid"""
class UnexpectedRPCDataFormatFromClient(Error):
"""Borg {}: Got unexpected RPC data format from client."""
class UnexpectedRPCDataFormatFromServer(Error):
"""Got unexpected RPC data format from server."""
class RepositoryServer: # pragma: no cover
rpc_methods = (
'__len__',
'check',
'commit',
'delete',
'destroy',
'get',
'list',
'negotiate',
'open',
'put',
'rollback',
'save_key',
'load_key',
'break_lock',
)
def __init__(self, restrict_to_paths, append_only):
self.repository = None
self.restrict_to_paths = restrict_to_paths
self.append_only = append_only
def serve(self):
stdin_fd = sys.stdin.fileno()
stdout_fd = sys.stdout.fileno()
stderr_fd = sys.stdout.fileno()
# Make stdin non-blocking
fl = fcntl.fcntl(stdin_fd, fcntl.F_GETFL)
fcntl.fcntl(stdin_fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
# Make stdout blocking
fl = fcntl.fcntl(stdout_fd, fcntl.F_GETFL)
fcntl.fcntl(stdout_fd, fcntl.F_SETFL, fl & ~os.O_NONBLOCK)
# Make stderr blocking
fl = fcntl.fcntl(stderr_fd, fcntl.F_GETFL)
fcntl.fcntl(stderr_fd, fcntl.F_SETFL, fl & ~os.O_NONBLOCK)
unpacker = msgpack.Unpacker(use_list=False)
while True:
r, w, es = select.select([stdin_fd], [], [], 10)
if r:
data = os.read(stdin_fd, BUFSIZE)
if not data:
if self.repository is not None:
self.repository.close()
else:
os.write(stderr_fd, "Borg {}: Got connection close before repository was opened.\n"
.format(__version__).encode())
return
unpacker.feed(data)
for unpacked in unpacker:
if not (isinstance(unpacked, tuple) and len(unpacked) == 4):
if self.repository is not None:
self.repository.close()
raise UnexpectedRPCDataFormatFromClient(__version__)
type, msgid, method, args = unpacked
method = method.decode('ascii')
try:
if method not in self.rpc_methods:
raise InvalidRPCMethod(method)
try:
f = getattr(self, method)
except AttributeError:
f = getattr(self.repository, method)
res = f(*args)
except BaseException as e:
# These exceptions are reconstructed on the client end in RemoteRepository.call_many(),
# and will be handled just like locally raised exceptions. Suppress the remote traceback
# for these, except ErrorWithTraceback, which should always display a traceback.
if not isinstance(e, (Repository.DoesNotExist, Repository.AlreadyExists, PathNotAllowed)):
logging.exception('Borg %s: exception in RPC call:', __version__)
logging.error(sysinfo())
exc = "Remote Exception (see remote log for the traceback)"
os.write(stdout_fd, msgpack.packb((1, msgid, e.__class__.__name__, exc)))
else:
os.write(stdout_fd, msgpack.packb((1, msgid, None, res)))
if es:
self.repository.close()
return
def negotiate(self, versions):
return RPC_PROTOCOL_VERSION
def open(self, path, create=False, lock_wait=None, lock=True, exclusive=None, append_only=False):
path = os.fsdecode(path)
if path.startswith('/~'): # /~/x = path x relative to home dir, /~username/x = relative to "user" home dir
path = path[1:]
elif path.startswith('/./'): # /./x = path x relative to cwd
path = path[3:]
path = os.path.realpath(os.path.expanduser(path))
if self.restrict_to_paths:
# if --restrict-to-path P is given, we make sure that we only operate in/below path P.
# for the prefix check, it is important that the compared pathes both have trailing slashes,
# so that a path /foobar will NOT be accepted with --restrict-to-path /foo option.
path_with_sep = os.path.join(path, '') # make sure there is a trailing slash (os.sep)
for restrict_to_path in self.restrict_to_paths:
restrict_to_path_with_sep = os.path.join(os.path.realpath(restrict_to_path), '') # trailing slash
if path_with_sep.startswith(restrict_to_path_with_sep):
break
else:
raise PathNotAllowed(path)
self.repository = Repository(path, create, lock_wait=lock_wait, lock=lock,
append_only=self.append_only or append_only,
exclusive=exclusive)
self.repository.__enter__() # clean exit handled by serve() method
return self.repository.id
class RemoteRepository:
extra_test_args = []
class RPCError(Exception):
def __init__(self, name, remote_type):
self.name = name
self.remote_type = remote_type
class NoAppendOnlyOnServer(Error):
"""Server does not support --append-only."""
def __init__(self, location, create=False, exclusive=False, lock_wait=None, lock=True, append_only=False, args=None):
self.location = self._location = location
self.preload_ids = []
self.msgid = 0
self.to_send = b''
self.cache = {}
self.ignore_responses = set()
self.responses = {}
self.unpacker = msgpack.Unpacker(use_list=False)
self.p = None
testing = location.host == '__testsuite__'
borg_cmd = self.borg_cmd(args, testing)
env = dict(os.environ)
if not testing:
borg_cmd = self.ssh_cmd(location) + borg_cmd
# pyinstaller binary adds LD_LIBRARY_PATH=/tmp/_ME... but we do not want
# that the system's ssh binary picks up (non-matching) libraries from there
env.pop('LD_LIBRARY_PATH', None)
env.pop('BORG_PASSPHRASE', None) # security: do not give secrets to subprocess
env['BORG_VERSION'] = __version__
self.p = Popen(borg_cmd, bufsize=0, stdin=PIPE, stdout=PIPE, stderr=PIPE, env=env)
self.stdin_fd = self.p.stdin.fileno()
self.stdout_fd = self.p.stdout.fileno()
self.stderr_fd = self.p.stderr.fileno()
fcntl.fcntl(self.stdin_fd, fcntl.F_SETFL, fcntl.fcntl(self.stdin_fd, fcntl.F_GETFL) | os.O_NONBLOCK)
fcntl.fcntl(self.stdout_fd, fcntl.F_SETFL, fcntl.fcntl(self.stdout_fd, fcntl.F_GETFL) | os.O_NONBLOCK)
fcntl.fcntl(self.stderr_fd, fcntl.F_SETFL, fcntl.fcntl(self.stderr_fd, fcntl.F_GETFL) | os.O_NONBLOCK)
self.r_fds = [self.stdout_fd, self.stderr_fd]
self.x_fds = [self.stdin_fd, self.stdout_fd, self.stderr_fd]
try:
try:
version = self.call('negotiate', RPC_PROTOCOL_VERSION)
except ConnectionClosed:
raise ConnectionClosedWithHint('Is borg working on the server?') from None
if version != RPC_PROTOCOL_VERSION:
raise Exception('Server insisted on using unsupported protocol version %d' % version)
try:
self.id = self.call('open', self.location.path, create, lock_wait, lock, exclusive, append_only)
except self.RPCError as err:
if err.remote_type != 'TypeError':
raise
msg = """\
Please note:
If you see a TypeError complaining about the number of positional arguments
given to open(), you can ignore it if it comes from a borg version < 1.0.7.
This TypeError is a cosmetic side effect of the compatibility code borg
clients >= 1.0.7 have to support older borg servers.
This problem will go away as soon as the server has been upgraded to 1.0.7+.
"""
# emit this msg in the same way as the "Remote: ..." lines that show the remote TypeError
sys.stderr.write(msg)
if append_only:
raise self.NoAppendOnlyOnServer()
self.id = self.call('open', self.location.path, create, lock_wait, lock)
except Exception:
self.close()
raise
def __del__(self):
if len(self.responses):
logging.debug("still %d cached responses left in RemoteRepository" % (len(self.responses),))
if self.p:
self.close()
assert False, "cleanup happened in Repository.__del__"
def __repr__(self):
return '<%s %s>' % (self.__class__.__name__, self.location.canonical_path())
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
try:
if exc_type is not None:
self.rollback()
finally:
# in any case, we want to cleanly close the repo, even if the
# rollback can not succeed (e.g. because the connection was
# already closed) and raised another exception:
self.close()
def borg_cmd(self, args, testing):
"""return a borg serve command line"""
# give some args/options to "borg serve" process as they were given to us
opts = []
if args is not None:
opts.append('--umask=%03o' % args.umask)
root_logger = logging.getLogger()
if root_logger.isEnabledFor(logging.DEBUG):
opts.append('--debug')
elif root_logger.isEnabledFor(logging.INFO):
opts.append('--info')
elif root_logger.isEnabledFor(logging.WARNING):
pass # warning is default
elif root_logger.isEnabledFor(logging.ERROR):
opts.append('--error')
elif root_logger.isEnabledFor(logging.CRITICAL):
opts.append('--critical')
else:
raise ValueError('log level missing, fix this code')
if testing:
return [sys.executable, '-m', 'borg.archiver', 'serve'] + opts + self.extra_test_args
else: # pragma: no cover
remote_path = args.remote_path or os.environ.get('BORG_REMOTE_PATH', 'borg')
remote_path = replace_placeholders(remote_path)
return [remote_path, 'serve'] + opts
def ssh_cmd(self, location):
"""return a ssh command line that can be prefixed to a borg command line"""
args = shlex.split(os.environ.get('BORG_RSH', 'ssh'))
if location.port:
args += ['-p', str(location.port)]
if location.user:
args.append('%s@%s' % (location.user, location.host))
else:
args.append('%s' % location.host)
return args
def call(self, cmd, *args, **kw):
for resp in self.call_many(cmd, [args], **kw):
return resp
def call_many(self, cmd, calls, wait=True, is_preloaded=False):
if not calls:
return
def fetch_from_cache(args):
msgid = self.cache[args].pop(0)
if not self.cache[args]:
del self.cache[args]
return msgid
def handle_error(error, res):
if error == b'DoesNotExist':
raise Repository.DoesNotExist(self.location.orig)
elif error == b'AlreadyExists':
raise Repository.AlreadyExists(self.location.orig)
elif error == b'CheckNeeded':
raise Repository.CheckNeeded(self.location.orig)
elif error == b'IntegrityError':
raise IntegrityError(res)
elif error == b'PathNotAllowed':
raise PathNotAllowed(*res)
elif error == b'ObjectNotFound':
raise Repository.ObjectNotFound(res[0], self.location.orig)
elif error == b'InvalidRPCMethod':
raise InvalidRPCMethod(*res)
else:
raise self.RPCError(res.decode('utf-8'), error.decode('utf-8'))
calls = list(calls)
waiting_for = []
while wait or calls:
while waiting_for:
try:
error, res = self.responses.pop(waiting_for[0])
waiting_for.pop(0)
if error:
handle_error(error, res)
else:
yield res
if not waiting_for and not calls:
return
except KeyError:
break
if self.to_send or ((calls or self.preload_ids) and len(waiting_for) < MAX_INFLIGHT):
w_fds = [self.stdin_fd]
else:
w_fds = []
r, w, x = select.select(self.r_fds, w_fds, self.x_fds, 1)
if x:
raise Exception('FD exception occurred')
for fd in r:
if fd is self.stdout_fd:
data = os.read(fd, BUFSIZE)
if not data:
raise ConnectionClosed()
self.unpacker.feed(data)
for unpacked in self.unpacker:
if not (isinstance(unpacked, tuple) and len(unpacked) == 4):
raise UnexpectedRPCDataFormatFromServer()
type, msgid, error, res = unpacked
if msgid in self.ignore_responses:
self.ignore_responses.remove(msgid)
if error:
handle_error(error, res)
else:
self.responses[msgid] = error, res
elif fd is self.stderr_fd:
data = os.read(fd, 32768)
if not data:
raise ConnectionClosed()
data = data.decode('utf-8')
for line in data.splitlines(keepends=True):
if line.startswith('$LOG '):
_, level, msg = line.split(' ', 2)
level = getattr(logging, level, logging.CRITICAL) # str -> int
logging.log(level, msg.rstrip())
else:
sys.stderr.write("Remote: " + line)
if w:
while not self.to_send and (calls or self.preload_ids) and len(waiting_for) < MAX_INFLIGHT:
if calls:
if is_preloaded:
if calls[0] in self.cache:
waiting_for.append(fetch_from_cache(calls.pop(0)))
else:
args = calls.pop(0)
if cmd == 'get' and args in self.cache:
waiting_for.append(fetch_from_cache(args))
else:
self.msgid += 1
waiting_for.append(self.msgid)
self.to_send = msgpack.packb((1, self.msgid, cmd, args))
if not self.to_send and self.preload_ids:
args = (self.preload_ids.pop(0),)
self.msgid += 1
self.cache.setdefault(args, []).append(self.msgid)
self.to_send = msgpack.packb((1, self.msgid, cmd, args))
if self.to_send:
try:
self.to_send = self.to_send[os.write(self.stdin_fd, self.to_send):]
except OSError as e:
# io.write might raise EAGAIN even though select indicates
# that the fd should be writable
if e.errno != errno.EAGAIN:
raise
self.ignore_responses |= set(waiting_for)
def check(self, repair=False, save_space=False):
return self.call('check', repair, save_space)
def commit(self, save_space=False):
return self.call('commit', save_space)
def rollback(self, *args):
return self.call('rollback')
def destroy(self):
return self.call('destroy')
def __len__(self):
return self.call('__len__')
def list(self, limit=None, marker=None):
return self.call('list', limit, marker)
def get(self, id_):
for resp in self.get_many([id_]):
return resp
def get_many(self, ids, is_preloaded=False):
for resp in self.call_many('get', [(id_,) for id_ in ids], is_preloaded=is_preloaded):
yield resp
def put(self, id_, data, wait=True):
return self.call('put', id_, data, wait=wait)
def delete(self, id_, wait=True):
return self.call('delete', id_, wait=wait)
def save_key(self, keydata):
return self.call('save_key', keydata)
def load_key(self):
return self.call('load_key')
def break_lock(self):
return self.call('break_lock')
def close(self):
if self.p:
self.p.stdin.close()
self.p.stdout.close()
self.p.wait()
self.p = None
def preload(self, ids):
self.preload_ids += ids
class RepositoryNoCache:
"""A not caching Repository wrapper, passes through to repository.
Just to have same API (including the context manager) as RepositoryCache.
"""
def __init__(self, repository):
self.repository = repository
def close(self):
pass
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
self.close()
def get(self, key):
return next(self.get_many([key]))
def get_many(self, keys):
for data in self.repository.get_many(keys):
yield data
class RepositoryCache(RepositoryNoCache):
"""A caching Repository wrapper
Caches Repository GET operations using a local temporary Repository.
"""
# maximum object size that will be cached, 64 kiB.
THRESHOLD = 2**16
def __init__(self, repository):
super().__init__(repository)
tmppath = tempfile.mkdtemp(prefix='borg-tmp')
self.caching_repo = Repository(tmppath, create=True, exclusive=True)
self.caching_repo.__enter__() # handled by context manager in base class
def close(self):
if self.caching_repo is not None:
self.caching_repo.destroy()
self.caching_repo = None
def get_many(self, keys):
unknown_keys = [key for key in keys if key not in self.caching_repo]
repository_iterator = zip(unknown_keys, self.repository.get_many(unknown_keys))
for key in keys:
try:
yield self.caching_repo.get(key)
except Repository.ObjectNotFound:
for key_, data in repository_iterator:
if key_ == key:
if len(data) <= self.THRESHOLD:
self.caching_repo.put(key, data)
yield data
break
# Consume any pending requests
for _ in repository_iterator:
pass
def cache_if_remote(repository):
if isinstance(repository, RemoteRepository):
return RepositoryCache(repository)
else:
return RepositoryNoCache(repository)