# server.py -- Implementation of the server side git protocols # Copyright (C) 2008 John Carr # Copyright(C) 2011-2012 Jelmer Vernooij # # SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later # Dulwich is dual-licensed under the Apache License, Version 2.0 and the GNU # General Public License as public by the Free Software Foundation; version 2.0 # or (at your option) any later version. You can redistribute it and/or # modify it under the terms of either of these two licenses. # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # # You should have received a copy of the licenses; if not, see # for a copy of the GNU General Public License # and for a copy of the Apache # License, Version 2.0. # """Git smart network protocol server implementation. For more detailed implementation on the network protocol, see the Documentation/technical directory in the cgit distribution, and in particular: * Documentation/technical/protocol-capabilities.txt * Documentation/technical/pack-protocol.txt Currently supported capabilities: * include-tag * thin-pack * multi_ack_detailed * multi_ack * side-band-64k * ofs-delta * no-progress * report-status * delete-refs * shallow * symref """ import collections import os import socket import socketserver import sys import time import zlib from collections.abc import Iterable, Iterator from functools import partial from typing import Optional, cast from typing import Protocol as TypingProtocol from dulwich import log_utils from .archive import tar_stream from .errors import ( ApplyDeltaError, ChecksumMismatch, GitProtocolError, HookError, NotGitRepository, ObjectFormatException, UnexpectedCommandError, ) from .object_store import peel_sha from .objects import Commit, ObjectID, valid_hexsha from .pack import ObjectContainer, PackedObjectContainer, write_pack_from_container from .protocol import ( CAPABILITIES_REF, CAPABILITY_AGENT, CAPABILITY_DELETE_REFS, CAPABILITY_INCLUDE_TAG, CAPABILITY_MULTI_ACK, CAPABILITY_MULTI_ACK_DETAILED, CAPABILITY_NO_DONE, CAPABILITY_NO_PROGRESS, CAPABILITY_OFS_DELTA, CAPABILITY_QUIET, CAPABILITY_REPORT_STATUS, CAPABILITY_SHALLOW, CAPABILITY_SIDE_BAND_64K, CAPABILITY_THIN_PACK, COMMAND_DEEPEN, COMMAND_DONE, COMMAND_HAVE, COMMAND_SHALLOW, COMMAND_UNSHALLOW, COMMAND_WANT, MULTI_ACK, MULTI_ACK_DETAILED, NAK_LINE, SIDE_BAND_CHANNEL_DATA, SIDE_BAND_CHANNEL_FATAL, SIDE_BAND_CHANNEL_PROGRESS, SINGLE_ACK, TCP_GIT_PORT, ZERO_SHA, BufferedPktLineWriter, Protocol, ReceivableProtocol, ack_type, capability_agent, extract_capabilities, extract_want_line_capabilities, format_ack_line, format_ref_line, format_shallow_line, format_unshallow_line, symref_capabilities, ) from .refs import PEELED_TAG_SUFFIX, RefsContainer, write_info_refs from .repo import Repo logger = log_utils.getLogger(__name__) class Backend: """A backend for the Git smart server implementation.""" def open_repository(self, path) -> "BackendRepo": """Open the repository at a path. Args: path: Path to the repository Raises: NotGitRepository: no git repository was found at path Returns: Instance of BackendRepo """ raise NotImplementedError(self.open_repository) class BackendRepo(TypingProtocol): """Repository abstraction used by the Git server. The methods required here are a subset of those provided by dulwich.repo.Repo. """ object_store: PackedObjectContainer refs: RefsContainer def get_refs(self) -> dict[bytes, bytes]: """Get all the refs in the repository. Returns: dict of name -> sha """ raise NotImplementedError def get_peeled(self, name: bytes) -> Optional[bytes]: """Return the cached peeled value of a ref, if available. Args: name: Name of the ref to peel Returns: The peeled value of the ref. If the ref is known not point to a tag, this will be the SHA the ref refers to. If no cached information about a tag is available, this method may return None, but it should attempt to peel the tag if possible. """ return None def find_missing_objects( self, determine_wants, graph_walker, progress, get_tagged=None ) -> Iterator[ObjectID]: """Yield the objects required for a list of commits. Args: progress: is a callback to send progress messages to the client get_tagged: Function that returns a dict of pointed-to sha -> tag sha for including tags. """ raise NotImplementedError class DictBackend(Backend): """Trivial backend that looks up Git repositories in a dictionary.""" def __init__(self, repos) -> None: self.repos = repos def open_repository(self, path: str) -> BackendRepo: logger.debug("Opening repository at %s", path) try: return self.repos[path] except KeyError as exc: raise NotGitRepository( "No git repository was found at {path}".format(**dict(path=path)) ) from exc class FileSystemBackend(Backend): """Simple backend looking up Git repositories in the local file system.""" def __init__(self, root=os.sep) -> None: super().__init__() self.root = (os.path.abspath(root) + os.sep).replace(os.sep * 2, os.sep) def open_repository(self, path): logger.debug("opening repository at %s", path) abspath = os.path.abspath(os.path.join(self.root, path)) + os.sep normcase_abspath = os.path.normcase(abspath) normcase_root = os.path.normcase(self.root) if not normcase_abspath.startswith(normcase_root): raise NotGitRepository(f"Path {path!r} not inside root {self.root!r}") return Repo(abspath) class Handler: """Smart protocol command handler base class.""" def __init__(self, backend, proto, stateless_rpc=False) -> None: self.backend = backend self.proto = proto self.stateless_rpc = stateless_rpc def handle(self) -> None: raise NotImplementedError(self.handle) class PackHandler(Handler): """Protocol handler for packs.""" def __init__(self, backend, proto, stateless_rpc=False) -> None: super().__init__(backend, proto, stateless_rpc) self._client_capabilities: Optional[set[bytes]] = None # Flags needed for the no-done capability self._done_received = False @classmethod def capabilities(cls) -> Iterable[bytes]: raise NotImplementedError(cls.capabilities) @classmethod def innocuous_capabilities(cls) -> Iterable[bytes]: return [ CAPABILITY_INCLUDE_TAG, CAPABILITY_THIN_PACK, CAPABILITY_NO_PROGRESS, CAPABILITY_OFS_DELTA, capability_agent(), ] @classmethod def required_capabilities(cls) -> Iterable[bytes]: """Return a list of capabilities that we require the client to have.""" return [] def set_client_capabilities(self, caps: Iterable[bytes]) -> None: allowable_caps = set(self.innocuous_capabilities()) allowable_caps.update(self.capabilities()) for cap in caps: if cap.startswith(CAPABILITY_AGENT + b"="): continue if cap not in allowable_caps: raise GitProtocolError( f"Client asked for capability {cap!r} that was not advertised." ) for cap in self.required_capabilities(): if cap not in caps: raise GitProtocolError( f"Client does not support required capability {cap!r}." ) self._client_capabilities = set(caps) logger.info("Client capabilities: %s", caps) def has_capability(self, cap: bytes) -> bool: if self._client_capabilities is None: raise GitProtocolError( f"Server attempted to access capability {cap!r} before asking client" ) return cap in self._client_capabilities def notify_done(self) -> None: self._done_received = True class UploadPackHandler(PackHandler): """Protocol handler for uploading a pack to the client.""" def __init__( self, backend, args, proto, stateless_rpc=False, advertise_refs=False ) -> None: super().__init__(backend, proto, stateless_rpc=stateless_rpc) self.repo = backend.open_repository(args[0]) self._graph_walker = None self.advertise_refs = advertise_refs # A state variable for denoting that the have list is still # being processed, and the client is not accepting any other # data (such as side-band, see the progress method here). self._processing_have_lines = False @classmethod def capabilities(cls): return [ CAPABILITY_MULTI_ACK_DETAILED, CAPABILITY_MULTI_ACK, CAPABILITY_SIDE_BAND_64K, CAPABILITY_THIN_PACK, CAPABILITY_OFS_DELTA, CAPABILITY_NO_PROGRESS, CAPABILITY_INCLUDE_TAG, CAPABILITY_SHALLOW, CAPABILITY_NO_DONE, ] @classmethod def required_capabilities(cls): return ( CAPABILITY_SIDE_BAND_64K, CAPABILITY_THIN_PACK, CAPABILITY_OFS_DELTA, ) def progress(self, message: bytes) -> None: pass def _start_pack_send_phase(self) -> None: if self.has_capability(CAPABILITY_SIDE_BAND_64K): # The provided haves are processed, and it is safe to send side- # band data now. if not self.has_capability(CAPABILITY_NO_PROGRESS): self.progress = partial( # type: ignore self.proto.write_sideband, SIDE_BAND_CHANNEL_PROGRESS ) self.write_pack_data = partial( self.proto.write_sideband, SIDE_BAND_CHANNEL_DATA ) else: self.write_pack_data = self.proto.write def get_tagged(self, refs=None, repo=None) -> dict[ObjectID, ObjectID]: """Get a dict of peeled values of tags to their original tag shas. Args: refs: dict of refname -> sha of possible tags; defaults to all of the backend's refs. repo: optional Repo instance for getting peeled refs; defaults to the backend's repo, if available Returns: dict of peeled_sha -> tag_sha, where tag_sha is the sha of a tag whose peeled value is peeled_sha. """ if not self.has_capability(CAPABILITY_INCLUDE_TAG): return {} if refs is None: refs = self.repo.get_refs() if repo is None: repo = getattr(self.repo, "repo", None) if repo is None: # Bail if we don't have a Repo available; this is ok since # clients must be able to handle if the server doesn't include # all relevant tags. # TODO: fix behavior when missing return {} # TODO(jelmer): Integrate this with the refs logic in # Repo.find_missing_objects tagged = {} for name, sha in refs.items(): peeled_sha = repo.get_peeled(name) if peeled_sha != sha: tagged[peeled_sha] = sha return tagged def handle(self) -> None: # Note the fact that client is only processing responses related # to the have lines it sent, and any other data (including side- # band) will be be considered a fatal error. self._processing_have_lines = True graph_walker = _ProtocolGraphWalker( self, self.repo.object_store, self.repo.get_peeled, self.repo.refs.get_symrefs, ) wants = [] def wants_wrapper(refs, **kwargs): wants.extend(graph_walker.determine_wants(refs, **kwargs)) return wants missing_objects = self.repo.find_missing_objects( wants_wrapper, graph_walker, self.progress, get_tagged=self.get_tagged, ) object_ids = list(missing_objects) # Did the process short-circuit (e.g. in a stateless RPC call)? Note # that the client still expects a 0-object pack in most cases. # Also, if it also happens that the object_iter is instantiated # with a graph walker with an implementation that talks over the # wire (which is this instance of this class) this will actually # iterate through everything and write things out to the wire. if len(wants) == 0: return if not graph_walker.handle_done( not self.has_capability(CAPABILITY_NO_DONE), self._done_received ): return self._start_pack_send_phase() self.progress((f"counting objects: {len(object_ids)}, done.\n").encode("ascii")) write_pack_from_container( self.write_pack_data, self.repo.object_store, object_ids ) # we are done self.proto.write_pkt_line(None) def _split_proto_line(line, allowed): """Split a line read from the wire. Args: line: The line read from the wire. allowed: An iterable of command names that should be allowed. Command names not listed below as possible return values will be ignored. If None, any commands from the possible return values are allowed. Returns: a tuple having one of the following forms: ('want', obj_id) ('have', obj_id) ('done', None) (None, None) (for a flush-pkt) Raises: UnexpectedCommandError: if the line cannot be parsed into one of the allowed return values. """ if not line: fields = [None] else: fields = line.rstrip(b"\n").split(b" ", 1) command = fields[0] if allowed is not None and command not in allowed: raise UnexpectedCommandError(command) if len(fields) == 1 and command in (COMMAND_DONE, None): return (command, None) elif len(fields) == 2: if command in ( COMMAND_WANT, COMMAND_HAVE, COMMAND_SHALLOW, COMMAND_UNSHALLOW, ): if not valid_hexsha(fields[1]): raise GitProtocolError("Invalid sha") return tuple(fields) elif command == COMMAND_DEEPEN: return command, int(fields[1]) raise GitProtocolError(f"Received invalid line from client: {line!r}") def _find_shallow(store: ObjectContainer, heads, depth): """Find shallow commits according to a given depth. Args: store: An ObjectStore for looking up objects. heads: Iterable of head SHAs to start walking from. depth: The depth of ancestors to include. A depth of one includes only the heads themselves. Returns: A tuple of (shallow, not_shallow), sets of SHAs that should be considered shallow and unshallow according to the arguments. Note that these sets may overlap if a commit is reachable along multiple paths. """ parents: dict[bytes, list[bytes]] = {} def get_parents(sha): result = parents.get(sha, None) if not result: result = store[sha].parents parents[sha] = result return result todo = [] # stack of (sha, depth) for head_sha in heads: _unpeeled, peeled = peel_sha(store, head_sha) if isinstance(peeled, Commit): todo.append((peeled.id, 1)) not_shallow = set() shallow = set() while todo: sha, cur_depth = todo.pop() if cur_depth < depth: not_shallow.add(sha) new_depth = cur_depth + 1 todo.extend((p, new_depth) for p in get_parents(sha)) else: shallow.add(sha) return shallow, not_shallow def _want_satisfied(store: ObjectContainer, haves, want, earliest) -> bool: o = store[want] pending = collections.deque([o]) known = {want} while pending: commit = pending.popleft() if commit.id in haves: return True if not isinstance(commit, Commit): # non-commit wants are assumed to be satisfied continue for parent in commit.parents: if parent in known: continue known.add(parent) parent_obj = store[parent] assert isinstance(parent_obj, Commit) # TODO: handle parents with later commit times than children if parent_obj.commit_time >= earliest: pending.append(parent_obj) return False def _all_wants_satisfied(store: ObjectContainer, haves, wants) -> bool: """Check whether all the current wants are satisfied by a set of haves. Args: store: Object store to retrieve objects from haves: A set of commits we know the client has. wants: A set of commits the client wants Note: Wants are specified with set_wants rather than passed in since in the current interface they are determined outside this class. """ haves = set(haves) if haves: have_objs = [store[h] for h in haves] earliest = min([h.commit_time for h in have_objs if isinstance(h, Commit)]) else: earliest = 0 for want in wants: if not _want_satisfied(store, haves, want, earliest): return False return True class AckGraphWalkerImpl: def __init__(self, graph_walker): raise NotImplementedError def ack(self, have_ref: ObjectID) -> None: raise NotImplementedError class _ProtocolGraphWalker: """A graph walker that knows the git protocol. As a graph walker, this class implements ack(), next(), and reset(). It also contains some base methods for interacting with the wire and walking the commit tree. The work of determining which acks to send is passed on to the implementation instance stored in _impl. The reason for this is that we do not know at object creation time what ack level the protocol requires. A call to set_ack_type() is required to set up the implementation, before any calls to next() or ack() are made. """ def __init__( self, handler, object_store: ObjectContainer, get_peeled, get_symrefs ) -> None: self.handler = handler self.store: ObjectContainer = object_store self.get_peeled = get_peeled self.get_symrefs = get_symrefs self.proto = handler.proto self.stateless_rpc = handler.stateless_rpc self.advertise_refs = handler.advertise_refs self._wants: list[bytes] = [] self.shallow: set[bytes] = set() self.client_shallow: set[bytes] = set() self.unshallow: set[bytes] = set() self._cached = False self._cache: list[bytes] = [] self._cache_index = 0 self._impl: Optional[AckGraphWalkerImpl] = None def determine_wants(self, heads, depth=None): """Determine the wants for a set of heads. The given heads are advertised to the client, who then specifies which refs they want using 'want' lines. This portion of the protocol is the same regardless of ack type, and in fact is used to set the ack type of the ProtocolGraphWalker. If the client has the 'shallow' capability, this method also reads and responds to the 'shallow' and 'deepen' lines from the client. These are not part of the wants per se, but they set up necessary state for walking the graph. Additionally, later code depends on this method consuming everything up to the first 'have' line. Args: heads: a dict of refname->SHA1 to advertise Returns: a list of SHA1s requested by the client """ symrefs = self.get_symrefs() values = set(heads.values()) if self.advertise_refs or not self.stateless_rpc: for i, (ref, sha) in enumerate(sorted(heads.items())): try: peeled_sha = self.get_peeled(ref) except KeyError: # Skip refs that are inaccessible # TODO(jelmer): Integrate with Repo.find_missing_objects refs # logic. continue if i == 0: logger.info("Sending capabilities: %s", self.handler.capabilities()) line = format_ref_line( ref, sha, self.handler.capabilities() + symref_capabilities(symrefs.items()), ) else: line = format_ref_line(ref, sha) self.proto.write_pkt_line(line) if peeled_sha != sha: self.proto.write_pkt_line( format_ref_line(ref + PEELED_TAG_SUFFIX, peeled_sha) ) # i'm done.. self.proto.write_pkt_line(None) if self.advertise_refs: return [] # Now client will sending want want want commands want = self.proto.read_pkt_line() if not want: return [] line, caps = extract_want_line_capabilities(want) self.handler.set_client_capabilities(caps) self.set_ack_type(ack_type(caps)) allowed = (COMMAND_WANT, COMMAND_SHALLOW, COMMAND_DEEPEN, None) command, sha = _split_proto_line(line, allowed) want_revs = [] while command == COMMAND_WANT: if sha not in values: raise GitProtocolError(f"Client wants invalid object {sha}") want_revs.append(sha) command, sha = self.read_proto_line(allowed) self.set_wants(want_revs) if command in (COMMAND_SHALLOW, COMMAND_DEEPEN): self.unread_proto_line(command, sha) self._handle_shallow_request(want_revs) if self.stateless_rpc and self.proto.eof(): # The client may close the socket at this point, expecting a # flush-pkt from the server. We might be ready to send a packfile # at this point, so we need to explicitly short-circuit in this # case. return [] return want_revs def unread_proto_line(self, command, value) -> None: if isinstance(value, int): value = str(value).encode("ascii") self.proto.unread_pkt_line(command + b" " + value) def nak(self) -> None: pass def ack(self, have_ref): if len(have_ref) != 40: raise ValueError(f"invalid sha {have_ref!r}") return self._impl.ack(have_ref) def reset(self) -> None: self._cached = True self._cache_index = 0 def next(self): if not self._cached: if not self._impl and self.stateless_rpc: return None return next(self._impl) self._cache_index += 1 if self._cache_index > len(self._cache): return None return self._cache[self._cache_index] __next__ = next def read_proto_line(self, allowed): """Read a line from the wire. Args: allowed: An iterable of command names that should be allowed. Returns: A tuple of (command, value); see _split_proto_line. Raises: UnexpectedCommandError: If an error occurred reading the line. """ return _split_proto_line(self.proto.read_pkt_line(), allowed) def _handle_shallow_request(self, wants) -> None: while True: command, val = self.read_proto_line((COMMAND_DEEPEN, COMMAND_SHALLOW)) if command == COMMAND_DEEPEN: depth = val break self.client_shallow.add(val) self.read_proto_line((None,)) # consume client's flush-pkt shallow, not_shallow = _find_shallow(self.store, wants, depth) # Update self.shallow instead of reassigning it since we passed a # reference to it before this method was called. self.shallow.update(shallow - not_shallow) new_shallow = self.shallow - self.client_shallow unshallow = self.unshallow = not_shallow & self.client_shallow for sha in sorted(new_shallow): self.proto.write_pkt_line(format_shallow_line(sha)) for sha in sorted(unshallow): self.proto.write_pkt_line(format_unshallow_line(sha)) self.proto.write_pkt_line(None) def notify_done(self) -> None: # relay the message down to the handler. self.handler.notify_done() def send_ack(self, sha, ack_type=b"") -> None: self.proto.write_pkt_line(format_ack_line(sha, ack_type)) def send_nak(self) -> None: self.proto.write_pkt_line(NAK_LINE) def handle_done(self, done_required, done_received): # Delegate this to the implementation. return self._impl.handle_done(done_required, done_received) def set_wants(self, wants) -> None: self._wants = wants def all_wants_satisfied(self, haves): """Check whether all the current wants are satisfied by a set of haves. Args: haves: A set of commits we know the client has. Note: Wants are specified with set_wants rather than passed in since in the current interface they are determined outside this class. """ return _all_wants_satisfied(self.store, haves, self._wants) def set_ack_type(self, ack_type) -> None: impl_classes: dict[int, type[AckGraphWalkerImpl]] = { MULTI_ACK: MultiAckGraphWalkerImpl, MULTI_ACK_DETAILED: MultiAckDetailedGraphWalkerImpl, SINGLE_ACK: SingleAckGraphWalkerImpl, } self._impl = impl_classes[ack_type](self) _GRAPH_WALKER_COMMANDS = (COMMAND_HAVE, COMMAND_DONE, None) class SingleAckGraphWalkerImpl(AckGraphWalkerImpl): """Graph walker implementation that speaks the single-ack protocol.""" def __init__(self, walker) -> None: self.walker = walker self._common: list[bytes] = [] def ack(self, have_ref) -> None: if not self._common: self.walker.send_ack(have_ref) self._common.append(have_ref) def next(self): command, sha = self.walker.read_proto_line(_GRAPH_WALKER_COMMANDS) if command in (None, COMMAND_DONE): # defer the handling of done self.walker.notify_done() return None elif command == COMMAND_HAVE: return sha __next__ = next def handle_done(self, done_required, done_received) -> bool: if not self._common: self.walker.send_nak() if done_required and not done_received: # we are not done, especially when done is required; skip # the pack for this request and especially do not handle # the done. return False if not done_received and not self._common: # Okay we are not actually done then since the walker picked # up no haves. This is usually triggered when client attempts # to pull from a source that has no common base_commit. # See: test_server.MultiAckDetailedGraphWalkerImplTestCase.\ # test_multi_ack_stateless_nodone return False return True class MultiAckGraphWalkerImpl(AckGraphWalkerImpl): """Graph walker implementation that speaks the multi-ack protocol.""" def __init__(self, walker) -> None: self.walker = walker self._found_base = False self._common: list[bytes] = [] def ack(self, have_ref) -> None: self._common.append(have_ref) if not self._found_base: self.walker.send_ack(have_ref, b"continue") if self.walker.all_wants_satisfied(self._common): self._found_base = True # else we blind ack within next def next(self): while True: command, sha = self.walker.read_proto_line(_GRAPH_WALKER_COMMANDS) if command is None: self.walker.send_nak() # in multi-ack mode, a flush-pkt indicates the client wants to # flush but more have lines are still coming continue elif command == COMMAND_DONE: self.walker.notify_done() return None elif command == COMMAND_HAVE: if self._found_base: # blind ack self.walker.send_ack(sha, b"continue") return sha __next__ = next def handle_done(self, done_required, done_received) -> bool: if done_required and not done_received: # we are not done, especially when done is required; skip # the pack for this request and especially do not handle # the done. return False if not done_received and not self._common: # Okay we are not actually done then since the walker picked # up no haves. This is usually triggered when client attempts # to pull from a source that has no common base_commit. # See: test_server.MultiAckDetailedGraphWalkerImplTestCase.\ # test_multi_ack_stateless_nodone return False # don't nak unless no common commits were found, even if not # everything is satisfied if self._common: self.walker.send_ack(self._common[-1]) else: self.walker.send_nak() return True class MultiAckDetailedGraphWalkerImpl(AckGraphWalkerImpl): """Graph walker implementation speaking the multi-ack-detailed protocol.""" def __init__(self, walker) -> None: self.walker = walker self._common: list[bytes] = [] def ack(self, have_ref) -> None: # Should only be called iff have_ref is common self._common.append(have_ref) self.walker.send_ack(have_ref, b"common") def next(self): while True: command, sha = self.walker.read_proto_line(_GRAPH_WALKER_COMMANDS) if command is None: if self.walker.all_wants_satisfied(self._common): self.walker.send_ack(self._common[-1], b"ready") self.walker.send_nak() if self.walker.stateless_rpc: # The HTTP version of this request a flush-pkt always # signifies an end of request, so we also return # nothing here as if we are done (but not really, as # it depends on whether no-done capability was # specified and that's handled in handle_done which # may or may not call post_nodone_check depending on # that). return None elif command == COMMAND_DONE: # Let the walker know that we got a done. self.walker.notify_done() break elif command == COMMAND_HAVE: # return the sha and let the caller ACK it with the # above ack method. return sha # don't nak unless no common commits were found, even if not # everything is satisfied __next__ = next def handle_done(self, done_required, done_received) -> bool: if done_required and not done_received: # we are not done, especially when done is required; skip # the pack for this request and especially do not handle # the done. return False if not done_received and not self._common: # Okay we are not actually done then since the walker picked # up no haves. This is usually triggered when client attempts # to pull from a source that has no common base_commit. # See: test_server.MultiAckDetailedGraphWalkerImplTestCase.\ # test_multi_ack_stateless_nodone return False # don't nak unless no common commits were found, even if not # everything is satisfied if self._common: self.walker.send_ack(self._common[-1]) else: self.walker.send_nak() return True class ReceivePackHandler(PackHandler): """Protocol handler for downloading a pack from the client.""" def __init__( self, backend, args, proto, stateless_rpc=False, advertise_refs=False ) -> None: super().__init__(backend, proto, stateless_rpc=stateless_rpc) self.repo = backend.open_repository(args[0]) self.advertise_refs = advertise_refs @classmethod def capabilities(cls) -> Iterable[bytes]: return [ CAPABILITY_REPORT_STATUS, CAPABILITY_DELETE_REFS, CAPABILITY_QUIET, CAPABILITY_OFS_DELTA, CAPABILITY_SIDE_BAND_64K, CAPABILITY_NO_DONE, ] def _apply_pack( self, refs: list[tuple[bytes, bytes, bytes]] ) -> list[tuple[bytes, bytes]]: all_exceptions = ( IOError, OSError, ChecksumMismatch, ApplyDeltaError, AssertionError, socket.error, zlib.error, ObjectFormatException, ) status = [] will_send_pack = False for command in refs: if command[1] != ZERO_SHA: will_send_pack = True if will_send_pack: # TODO: more informative error messages than just the exception # string try: recv = getattr(self.proto, "recv", None) self.repo.object_store.add_thin_pack(self.proto.read, recv) status.append((b"unpack", b"ok")) except all_exceptions as e: status.append((b"unpack", str(e).replace("\n", "").encode("utf-8"))) # The pack may still have been moved in, but it may contain # broken objects. We trust a later GC to clean it up. else: # The git protocol want to find a status entry related to unpack # process even if no pack data has been sent. status.append((b"unpack", b"ok")) for oldsha, sha, ref in refs: ref_status = b"ok" try: if sha == ZERO_SHA: if CAPABILITY_DELETE_REFS not in self.capabilities(): raise GitProtocolError( "Attempted to delete refs without delete-refs capability." ) try: self.repo.refs.remove_if_equals(ref, oldsha) except all_exceptions: ref_status = b"failed to delete" else: try: self.repo.refs.set_if_equals(ref, oldsha, sha) except all_exceptions: ref_status = b"failed to write" except KeyError: ref_status = b"bad ref" status.append((ref, ref_status)) return status def _report_status(self, status: list[tuple[bytes, bytes]]) -> None: if self.has_capability(CAPABILITY_SIDE_BAND_64K): writer = BufferedPktLineWriter( lambda d: self.proto.write_sideband(SIDE_BAND_CHANNEL_DATA, d) ) write = writer.write def flush() -> None: writer.flush() self.proto.write_pkt_line(None) else: write = self.proto.write_pkt_line def flush() -> None: pass for name, msg in status: if name == b"unpack": write(b"unpack " + msg + b"\n") elif msg == b"ok": write(b"ok " + name + b"\n") else: write(b"ng " + name + b" " + msg + b"\n") write(None) flush() def _on_post_receive(self, client_refs) -> None: hook = self.repo.hooks.get("post-receive", None) if not hook: return try: output = hook.execute(client_refs) if output: self.proto.write_sideband(SIDE_BAND_CHANNEL_PROGRESS, output) except HookError as err: self.proto.write_sideband(SIDE_BAND_CHANNEL_FATAL, str(err).encode("utf-8")) def handle(self) -> None: if self.advertise_refs or not self.stateless_rpc: refs = sorted(self.repo.get_refs().items()) symrefs = sorted(self.repo.refs.get_symrefs().items()) if not refs: refs = [(CAPABILITIES_REF, ZERO_SHA)] logger.info("Sending capabilities: %s", self.capabilities()) self.proto.write_pkt_line( format_ref_line( refs[0][0], refs[0][1], self.capabilities() + symref_capabilities(symrefs), ) ) for i in range(1, len(refs)): ref = refs[i] self.proto.write_pkt_line(format_ref_line(ref[0], ref[1])) self.proto.write_pkt_line(None) if self.advertise_refs: return client_refs = [] ref = self.proto.read_pkt_line() # if ref is none then client doesn't want to send us anything.. if ref is None: return ref, caps = extract_capabilities(ref) self.set_client_capabilities(caps) # client will now send us a list of (oldsha, newsha, ref) while ref: client_refs.append(ref.split()) ref = self.proto.read_pkt_line() # backend can now deal with this refs and read a pack using self.read status = self._apply_pack(client_refs) self._on_post_receive(client_refs) # when we have read all the pack from the client, send a status report # if the client asked for it if self.has_capability(CAPABILITY_REPORT_STATUS): self._report_status(status) class UploadArchiveHandler(Handler): def __init__(self, backend, args, proto, stateless_rpc=False) -> None: super().__init__(backend, proto, stateless_rpc) self.repo = backend.open_repository(args[0]) def handle(self) -> None: def write(x): return self.proto.write_sideband(SIDE_BAND_CHANNEL_DATA, x) arguments = [] for pkt in self.proto.read_pkt_seq(): (key, value) = pkt.split(b" ", 1) if key != b"argument": raise GitProtocolError(f"unknown command {key}") arguments.append(value.rstrip(b"\n")) prefix = b"" format = "tar" i = 0 store: ObjectContainer = self.repo.object_store while i < len(arguments): argument = arguments[i] if argument == b"--prefix": i += 1 prefix = arguments[i] elif argument == b"--format": i += 1 format = arguments[i].decode("ascii") else: commit_sha = self.repo.refs[argument] tree = store[cast(Commit, store[commit_sha]).tree] i += 1 self.proto.write_pkt_line(b"ACK") self.proto.write_pkt_line(None) for chunk in tar_stream( store, tree, mtime=time.time(), prefix=prefix, format=format ): write(chunk) self.proto.write_pkt_line(None) # Default handler classes for git services. DEFAULT_HANDLERS = { b"git-upload-pack": UploadPackHandler, b"git-receive-pack": ReceivePackHandler, b"git-upload-archive": UploadArchiveHandler, } class TCPGitRequestHandler(socketserver.StreamRequestHandler): def __init__(self, handlers, *args, **kwargs) -> None: self.handlers = handlers socketserver.StreamRequestHandler.__init__(self, *args, **kwargs) def handle(self) -> None: proto = ReceivableProtocol(self.connection.recv, self.wfile.write) command, args = proto.read_cmd() logger.info("Handling %s request, args=%s", command, args) cls = self.handlers.get(command, None) if not callable(cls): raise GitProtocolError(f"Invalid service {command}") h = cls(self.server.backend, args, proto) # type: ignore h.handle() class TCPGitServer(socketserver.TCPServer): allow_reuse_address = True serve = socketserver.TCPServer.serve_forever def _make_handler(self, *args, **kwargs): return TCPGitRequestHandler(self.handlers, *args, **kwargs) def __init__(self, backend, listen_addr, port=TCP_GIT_PORT, handlers=None) -> None: self.handlers = dict(DEFAULT_HANDLERS) if handlers is not None: self.handlers.update(handlers) self.backend = backend logger.info("Listening for TCP connections on %s:%d", listen_addr, port) socketserver.TCPServer.__init__(self, (listen_addr, port), self._make_handler) def verify_request(self, request, client_address) -> bool: logger.info("Handling request from %s", client_address) return True def handle_error(self, request, client_address) -> None: logger.exception( "Exception happened during processing of request from %s", client_address, ) def main(argv=sys.argv) -> None: """Entry point for starting a TCP git server.""" import optparse parser = optparse.OptionParser() parser.add_option( "-l", "--listen_address", dest="listen_address", default="localhost", help="Binding IP address.", ) parser.add_option( "-p", "--port", dest="port", type=int, default=TCP_GIT_PORT, help="Binding TCP port.", ) options, args = parser.parse_args(argv) log_utils.default_logging_config() if len(args) > 1: gitdir = args[1] else: gitdir = "." # TODO(jelmer): Support git-daemon-export-ok and --export-all. backend = FileSystemBackend(gitdir) server = TCPGitServer(backend, options.listen_address, options.port) server.serve_forever() def serve_command( handler_cls, argv=sys.argv, backend=None, inf=sys.stdin, outf=sys.stdout ) -> int: """Serve a single command. This is mostly useful for the implementation of commands used by e.g. git+ssh. Args: handler_cls: `Handler` class to use for the request argv: execv-style command-line arguments. Defaults to sys.argv. backend: `Backend` to use inf: File-like object to read from, defaults to standard input. outf: File-like object to write to, defaults to standard output. Returns: Exit code for use with sys.exit. 0 on success, 1 on failure. """ if backend is None: backend = FileSystemBackend() def send_fn(data) -> None: outf.write(data) outf.flush() proto = Protocol(inf.read, send_fn) handler = handler_cls(backend, argv[1:], proto) # FIXME: Catch exceptions and write a single-line summary to outf. handler.handle() return 0 def generate_info_refs(repo): """Generate an info refs file.""" refs = repo.get_refs() return write_info_refs(refs, repo.object_store) def generate_objects_info_packs(repo): """Generate an index for for packs.""" for pack in repo.object_store.packs: yield (b"P " + os.fsencode(pack.data.filename) + b"\n") def update_server_info(repo) -> None: """Generate server info for dumb file access. This generates info/refs and objects/info/packs, similar to "git update-server-info". """ repo._put_named_file( os.path.join("info", "refs"), b"".join(generate_info_refs(repo)) ) repo._put_named_file( os.path.join("objects", "info", "packs"), b"".join(generate_objects_info_packs(repo)), ) if __name__ == "__main__": main()