fixup! feat(core): add BleInterface to session handling

core/src/apps/debug/__init__.py

@@ -357,8 +357,6 @@ if __debug__:
     async def _no_op(_msg: Any) -> Success:
         return Success()
 
-    WIRE_BUFFER_DEBUG = bytearray(1024)
-
     async def handle_session(iface: WireInterface) -> None:
         from trezor import protobuf, wire
         from trezor.wire.codec import codec_v1
@@ -366,7 +364,7 @@ if __debug__:
 
         global DEBUG_CONTEXT
 
-        DEBUG_CONTEXT = ctx = CodecContext(iface, WIRE_BUFFER_DEBUG)
+        DEBUG_CONTEXT = ctx = CodecContext(iface, wire.BufferProvider(1024), "Debug")
 
         if storage.layout_watcher:
             try:

core/src/session.py

@@ -6,12 +6,7 @@ from trezor import log, loop, utils, wire, workflow
 import apps.base
 import usb
 
-_PROTOBUF_BUFFER_SIZE = const(8192)
-USB_BUFFER = bytearray(_PROTOBUF_BUFFER_SIZE)
-
-if utils.USE_BLE:
-    BLE_BUFFER = bytearray(_PROTOBUF_BUFFER_SIZE)
-
+buffer_provider = wire.BufferProvider(8192)
 
 apps.base.boot()
 
@@ -30,13 +25,13 @@ apps.base.set_homescreen()
 workflow.start_default()
 
 # initialize the wire codec over USB
-wire.setup(usb.iface_wire, USB_BUFFER)
+wire.setup(usb.iface_wire, buffer_provider, "USB")
 
 if utils.USE_BLE:
     import bluetooth
 
     # initialize the wire codec over BLE
-    wire.setup(bluetooth.iface_ble, BLE_BUFFER)
+    wire.setup(bluetooth.iface_ble, buffer_provider, "BLE")
 
 # start the event loop
 loop.run()

core/src/trezor/wire/__init__.py

@@ -47,13 +47,28 @@ if TYPE_CHECKING:
     LoadedMessageType = TypeVar("LoadedMessageType", bound=protobuf.MessageType)
 
 
-def setup(iface: WireInterface, buffer: bytearray) -> None:
+class BufferProvider:
+    def __init__(self, size):
+        self.buf = bytearray(size)
+        self.owner = None
+
+    def take(self, owner: str) -> bytearray | None:
+        if self.buf is None:
+            return None
+
+        buf = self.buf
+        self.buf = None
+        self.owner = owner
+        return buf
+
+
+def setup(iface: WireInterface, buffer_provider: BufferProvider, name: str) -> None:
     """Initialize the wire stack on the provided WireInterface."""
-    loop.schedule(handle_session(iface, buffer))
+    loop.schedule(handle_session(iface, buffer_provider, name))
 
 
-async def handle_session(iface: WireInterface, buffer: bytearray) -> None:
-    ctx = CodecContext(iface, buffer)
+async def handle_session(iface: WireInterface, buffer_provider: BufferProvider, name: str) -> None:
+    ctx = CodecContext(iface, buffer_provider, name)
     next_msg: protocol_common.Message | None = None
 
     # Take a mark of modules that are imported at this point, so we can

core/src/trezor/wire/codec/codec_context.py

@@ -5,12 +5,12 @@ from storage.cache_common import DataCache, InvalidSessionError
 from trezor import log, protobuf
 from trezor.wire.codec import codec_v1
 from trezor.wire.context import UnexpectedMessageException
-from trezor.wire.protocol_common import Context, Message
+from trezor.wire.protocol_common import Context, Message, WireError
 
 if TYPE_CHECKING:
     from typing import TypeVar
 
-    from trezor.wire import WireInterface
+    from trezor.wire import WireInterface, BufferProvider
 
     LoadedMessageType = TypeVar("LoadedMessageType", bound=protobuf.MessageType)
 
@@ -21,14 +21,29 @@ class CodecContext(Context):
     def __init__(
         self,
         iface: WireInterface,
-        buffer: bytearray,
+        buffer_provider: BufferProvider,
+        name: str,
     ) -> None:
-        self.buffer = buffer
+        self.buffer_provider = buffer_provider
+        self._buffer = None
+        self.name = name
         super().__init__(iface)
 
+    def get_buffer(self) -> bytearray:
+        if self._buffer is not None:
+            return self._buffer
+
+        self._buffer = self.buffer_provider.take(self.name)
+        if self._buffer is not None:
+            return self._buffer
+
+        # The exception should be caught by and handled by `wire.handle_session()` task.
+        # It doesn't terminate the "blocked" session (to allow sending error responses).
+        raise WireError(f"{self.buffer_provider.owner} session in progress, {self.name} is blocked")
+
     def read_from_wire(self) -> Awaitable[Message]:
         """Read a whole message from the wire without parsing it."""
-        return codec_v1.read_message(self.iface, self.buffer)
+        return codec_v1.read_message(self.iface, self.get_buffer)
 
     async def read(
         self,
@@ -81,10 +96,15 @@ class CodecContext(Context):
 
         msg_size = protobuf.encoded_length(msg)
 
-        if msg_size <= len(self.buffer):
-            # reuse preallocated
-            buffer = self.buffer
+        if self._buffer is not None:
+            buffer = self._buffer
         else:
+            # Allow sending small responses (for error reporting when another session is in progress
+            if msg_size > 128:
+                raise MemoryError(msg_size) ### FIXME
+            buffer = bytearray()
+
+        if msg_size > len(buffer):
             # message is too big, we need to allocate a new buffer
             buffer = bytearray(msg_size)
 

core/src/trezor/wire/codec/codec_v1.py

@@ -7,6 +7,7 @@ from trezor.wire.protocol_common import Message, WireError
 
 if TYPE_CHECKING:
     from trezorio import WireInterface
+    from typing import Callable
 
 _REP_MARKER = const(63)  # ord('?')
 _REP_MAGIC = const(35)  # org('#')
@@ -19,7 +20,7 @@ class CodecError(WireError):
     pass
 
 
-async def read_message(iface: WireInterface, buffer: utils.BufferType) -> Message:
+async def read_message(iface: WireInterface, buffer_getter: Callable[[], bytearray]) -> Message:
     read = loop.wait(iface.iface_num() | io.POLL_READ)
     report = bytearray(iface.RX_PACKET_LEN)
 
@@ -33,6 +34,7 @@ async def read_message(iface: WireInterface, buffer: utils.BufferType) -> Messag
     if magic1 != _REP_MAGIC or magic2 != _REP_MAGIC:
         raise CodecError("Invalid magic")
 
+    buffer = buffer_getter()  # will throw if other session is in progress
     read_and_throw_away = False
 
     if msize > len(buffer):