Initial server source import

2026-09-30 20:30:56 +03:00
commit 170dd941b9
498 changed files with 261563 additions and 0 deletions
@@ -0,0 +1,131 @@
+import os
+import socket
+import stat
+import struct
+import time
+
+from host_agent_protocol import (
+    CLIENT_CONNECT_TIMEOUT_SECONDS,
+    EXCHANGE_TIMEOUT_SECONDS,
+    HOST_AGENT_SOCKET_PATH,
+    MAX_RESPONSE_PAYLOAD_BYTES,
+    HostAgentAction,
+    HostAgentProtocolError,
+    HostAgentRequest,
+    HostAgentStatus,
+    decode_response_frame,
+    encode_request_frame,
+    receive_frame,
+    require_eof,
+    send_frame,
+)
+
+
+class HostAgentClientError(RuntimeError):
+    def __init__(self, category):
+        self.category = category
+        super().__init__('host operations agent request failed')
+
+
+class HostAgentUnavailableError(HostAgentClientError):
+    pass
+
+
+class HostAgentRejectedError(HostAgentClientError):
+    pass
+
+
+def _fixed_socket_is_safe():
+    try:
+        details = os.lstat(HOST_AGENT_SOCKET_PATH)
+    except OSError:
+        return False
+    return stat.S_ISSOCK(details.st_mode) and details.st_uid == 0
+
+
+def _peer_credentials(sock):
+    if not hasattr(socket, 'SO_PEERCRED'):
+        raise HostAgentUnavailableError('peer_credentials_unavailable')
+    try:
+        raw = sock.getsockopt(
+            socket.SOL_SOCKET, socket.SO_PEERCRED, struct.calcsize('3i'),
+        )
+        pid, uid, gid = struct.unpack('3i', raw)
+    except (OSError, struct.error) as exc:
+        raise HostAgentUnavailableError('peer_credentials_unavailable') from exc
+    # A peer outside the client's PID namespace is reported as PID 0 even
+    # though its UID/GID remain authoritative through SO_PEERCRED.
+    if pid < 0:
+        raise HostAgentUnavailableError('peer_identity_invalid')
+    return pid, uid, gid
+
+
+class HostAgentClient:
+    def __init__(self):
+        pass
+
+    @staticmethod
+    def is_available():
+        return _fixed_socket_is_safe()
+
+    def dispatch(
+        self, *, operation_id, action, active_config_sha256,
+        active_secrets_sha256, candidate_config_sha256,
+        candidate_secrets_sha256,
+    ):
+        try:
+            request = HostAgentRequest(
+                operation_id=operation_id,
+                action=HostAgentAction(action),
+                active_config_sha256=active_config_sha256,
+                active_secrets_sha256=active_secrets_sha256,
+                candidate_config_sha256=candidate_config_sha256,
+                candidate_secrets_sha256=candidate_secrets_sha256,
+            )
+            frame = encode_request_frame(request)
+        except (HostAgentProtocolError, TypeError, ValueError) as exc:
+            raise HostAgentRejectedError('request_invalid') from exc
+        if not _fixed_socket_is_safe():
+            raise HostAgentUnavailableError('socket_unavailable')
+        deadline = time.monotonic() + EXCHANGE_TIMEOUT_SECONDS
+        connection = None
+        response = None
+        try:
+            family = getattr(socket, 'AF_UNIX', None)
+            if family is None:
+                raise HostAgentUnavailableError('unix_socket_unavailable')
+            connection = socket.socket(family, socket.SOCK_STREAM)
+            connection.settimeout(min(
+                CLIENT_CONNECT_TIMEOUT_SECONDS,
+                max(0.001, deadline - time.monotonic()),
+            ))
+            connection.connect(HOST_AGENT_SOCKET_PATH)
+            _pid, peer_uid, _gid = _peer_credentials(connection)
+            if peer_uid != 0:
+                raise HostAgentUnavailableError('server_identity_invalid')
+            send_frame(connection, frame, deadline=deadline)
+            connection.shutdown(socket.SHUT_WR)
+            response = decode_response_frame(receive_frame(
+                connection, maximum=MAX_RESPONSE_PAYLOAD_BYTES, deadline=deadline,
+            ))
+            require_eof(connection, deadline=deadline)
+        except HostAgentClientError:
+            raise
+        except HostAgentProtocolError as exc:
+            raise HostAgentUnavailableError('response_invalid') from exc
+        except (OSError, TimeoutError) as exc:
+            raise HostAgentUnavailableError('transport_unavailable') from exc
+        finally:
+            if connection is not None:
+                try:
+                    connection.close()
+                except OSError:
+                    pass
+            connection = frame = request = family = None
+        if response.operation_id != operation_id:
+            raise HostAgentUnavailableError('response_identity_invalid')
+        if response.status is HostAgentStatus.ACCEPTED:
+            return response
+        if response.status is HostAgentStatus.REJECTED:
+            raise HostAgentRejectedError('request_rejected')
+        raise HostAgentUnavailableError('request_unavailable')