workflow monitor, reset_device layout work

- request/response manner of usual protobuf workflows is enforced, workflows are expected to either return a valid protobuf response, or raise an exception
- added wire.FailureError exception that allows workflow to provide Failure code & message
- pin workflows simplified

TODO: all this workflow work does not really belong in trezor.wire

src/apps/management/layout_reset_device.py

@@ -1,4 +1,5 @@
 from trezor import wire, ui
+from trezor.workflows.request_pin import request_new_pin
 from trezor.messages.wire_types import EntropyAck
 from trezor.ui.button import Button, CONFIRM_BUTTON, CONFIRM_BUTTON_ACTIVE
 from trezor.ui.scroll import paginate, render_scrollbar, animate_swipe
@@ -6,75 +7,72 @@ from trezor.crypto import hashlib, random, bip39
 from trezor.utils import unimport, chunks
 
 
+@unimport
 async def generate_mnemonic(strength, display_random, session_id):
     from trezor.messages.EntropyRequest import EntropyRequest
+    from trezor.messages.FailureType import Other
 
-    await wire.write_message(session_id, EntropyRequest())
+    if strength not in (128, 192, 256):
-    ack = await wire.read_message(session_id, EntropyAck)
+        raise wire.FailureError(Other, 'Invalid seed strength')
 
+    # if display_random:
+    #     raise wire.FailureError(Other, 'Entropy display not implemented')
+
+    ack = await wire.reply_message(session_id,
+                                   EntropyRequest(),
+                                   EntropyAck)
+
+    strength_bytes = strength // 8
     ctx = hashlib.sha256()
-    ctx.update(random.bytes(32))
+    ctx.update(random.bytes(strength_bytes))
-    ctx.update(ack.entropy)
+    ctx.update(ack.entropy[:strength_bytes])
     entropy = ctx.digest()
 
-    # TODO: handle strength
-    # TODO: handle display_random
-
     return bip39.from_data(entropy)
 
 
-async def request_new_pin():
+async def show_mnemonic_page(page, page_count, mnemonic):
-    from trezor.workflows.request_pin import request_pin
+    ui.clear()
+    ui.display.text(10, 30, 'Write down your seed',
+                    ui.BOLD, ui.LIGHT_GREEN, ui.BLACK)
+    render_scrollbar(page, page_count)
 
-    pin = await request_pin()
+    for pi, (wi, word) in enumerate(mnemonic[page]):
-    pin_again = await request_pin('Enter PIN again')
+        top = pi * 30 + 74
+        pos = wi + 1
+        ui.display.text_right(40, top, '%d.' % pos,
+                              ui.BOLD, ui.LIGHT_GREEN, ui.BLACK)
+        ui.display.text(45, top, '%s' % word,
+                        ui.BOLD, ui.WHITE, ui.BLACK)
 
-    if pin == pin_again:
+    if page + 1 == page_count:
-        return pin
+        await Button((0, 240 - 48, 240, 48), 'Finish',
+                     normal_style=CONFIRM_BUTTON,
+                     active_style=CONFIRM_BUTTON_ACTIVE)
     else:
-        raise Exception()  # TODO: wrong PIN should be handled in unified way
+        await animate_swipe()
 
 
 async def show_mnemonic(mnemonic):
+    first_page = const(0)
     words_per_page = const(4)
-    mnemonic_words = list(enumerate(mnemonic.split()))
+    words = list(enumerate(mnemonic.split()))
-    mnemonic_pages = list(chunks(mnemonic_words, words_per_page))
+    pages = list(chunks(words, words_per_page))
-
+    await paginate(show_mnemonic_page, len(pages), first_page, pages)
-    async def render(page, page_count):
-
-        # render header & scrollbar
-        ui.clear()
-        ui.display.text(10, 30, 'Write down your seed',
-                        ui.BOLD, ui.LIGHT_GREEN, ui.BLACK)
-        render_scrollbar(page, page_count)
-
-        # render mnemonic page
-        for pi, (wi, word) in enumerate(mnemonic_pages[page]):
-            top = pi * 30 + 74
-            pos = wi + 1
-            ui.display.text_right(40, top, '%d.' %
-                                  pos, ui.BOLD, ui.LIGHT_GREEN, ui.BLACK)
-            ui.display.text(45, top, '%s' % word, ui.BOLD, ui.WHITE, ui.BLACK)
-
-        if page + 1 == page_count:
-            await Button((0, 240 - 48, 240, 48), 'Finish',
-                         normal_style=CONFIRM_BUTTON,
-                         active_style=CONFIRM_BUTTON_ACTIVE)
-        else:
-            await animate_swipe()
-
-    await paginate(render, len(mnemonic_pages))
 
 
+@unimport
 async def layout_reset_device(message, session_id):
-    # TODO: Failure if not empty
+    from trezor.messages.Success import Success
 
-    mnemonic = await generate_mnemonic(
+    mnemonic = await generate_mnemonic(message.strength,
-        message.strength, message.display_random, session_id)
+                                       message.display_random,
+                                       session_id)
+    # await show_mnemonic(mnemonic)
 
-    # if m.pin_protection:
+    if message.pin_protection:
-    #     pin = yield from request_new_pin()
+        pin = await request_new_pin(session_id)
-    # else:
+    else:
-    #     pin = None
+        pin = None
 
-    await show_mnemonic(mnemonic)
+    return Success()

src/trezor/ui/scroll.py

@@ -11,10 +11,10 @@ async def change_page(page, page_count):
             return page - 1  # scroll up
 
 
-async def paginate(render_page, page_count, page=0):
+async def paginate(render_page, page_count, page=0, *args):
     while True:
         changer = change_page(page, page_count)
-        renderer = render_page(page, page_count)
+        renderer = render_page(page, page_count, *args)
         waiter = loop.Wait([changer, renderer])
         result = await waiter
         if changer in waiter.finished:
@@ -41,7 +41,7 @@ def render_scrollbar(page, page_count):
     if page_count * padding > screen_height:
         padding = screen_height // page_count
 
-    x = 225
+    x = const(225)
     y = (screen_height // 2) - (page_count // 2) * padding
 
     for i in range(0, page_count):

src/trezor/wire/__init__.py

@@ -40,8 +40,7 @@ def close_session(session_id):
 def register_type(wire_type, genfunc, *args):
     if wire_type in _workflow_genfuncs:
         raise KeyError('message of type %d already registered' % wire_type)
-    log.info(__name__, 'registering %s for type %d',
+    log.info(__name__, 'registering message type %d', wire_type)
-             (genfunc, args), wire_type)
     _workflow_genfuncs[wire_type] = (genfunc, args)
 
 
@@ -49,8 +48,8 @@ def register_session(session_id, handler):
     if session_id not in _opened_sessions:
         raise KeyError('session %d is unknown' % session_id)
     if session_id in _session_handlers:
-        raise KeyError('session %d is already registered' % session_id)
+        raise KeyError('session %d is already being listened on' % session_id)
-    log.info(__name__, 'registering %s for session %d', handler, session_id)
+    log.info(__name__, 'listening on session %d', session_id)
     _session_handlers[session_id] = handler
 
 
@@ -78,6 +77,7 @@ def setup():
 
 
 async def read_message(session_id, *exp_types):
+    log.info(__name__, 'reading message, one of %s', exp_types)
     future = Future()
     wire_decoder = decode_wire_stream(
         _dispatch_and_build_protobuf, session_id, exp_types, future)
@@ -87,6 +87,7 @@ async def read_message(session_id, *exp_types):
 
 
 async def write_message(session_id, pbuf_message):
+    log.info(__name__, 'writing message %s', pbuf_message)
     msg_data = await pbuf_message.dumps()
     msg_type = pbuf_message.message_type.wire_type
     writer = write_report_stream()
@@ -94,9 +95,56 @@ async def write_message(session_id, pbuf_message):
     encode_wire_message(msg_type, msg_data, session_id, writer)
 
 
+async def reply_message(session_id, pbuf_message, *exp_types):
+    await write_message(session_id, pbuf_message)
+    return await read_message(session_id, *exp_types)
+
+
+class FailureError(Exception):
+
+    def __init__(self, code, message):
+        super(FailureError, self).__init__(code, message)
+
+    def to_protobuf(self):
+        from trezor.messages.Failure import Failure
+        return Failure(code=self.args[0],
+                       message=self.args[1])
+
+
+async def monitor_workflow(workflow, session_id):
+    try:
+        result = await workflow
+
+    except FailureError as e:
+        await write_message(session_id, e.to_protobuf())
+        raise
+
+    except Exception as e:
+        from trezor.messages.Failure import Failure
+        from trezor.messages.FailureType import FirmwareError
+        await write_message(session_id,
+                            Failure(code=FirmwareError,
+                                    message='Firmware Error'))
+        raise
+
+    else:
+        if result is not None:
+            await write_message(session_id, result)
+        return result
+
+    finally:
+        if session_id in _opened_sessions:
+            wire_decoder = decode_wire_stream(
+                _handle_registered_type, session_id)
+            wire_decoder.send(None)
+            register_session(session_id, wire_decoder)
+
+
 def protobuf_handler(msg_type, data_len, session_id, callback, *args):
     def finalizer(message):
-        start_workflow(callback(message, session_id, *args))
+        workflow = callback(message, session_id, *args)
+        monitored = monitor_workflow(workflow, session_id)
+        start_workflow(monitored)
     pbuf_type = get_protobuf_type(msg_type)
     builder = build_protobuf_message(pbuf_type, finalizer)
     builder.send(None)
@@ -125,10 +173,6 @@ def _handle_unknown_session():
         yield  # TODO
 
 
-class UnexpectedMessageError(Exception):
-    pass
-
-
 def _dispatch_and_build_protobuf(msg_type, data_len, session_id, exp_types, future):
     if msg_type in exp_types:
         pbuf_type = get_protobuf_type(msg_type)
@@ -136,18 +180,20 @@ def _dispatch_and_build_protobuf(msg_type, data_len, session_id, exp_types, futu
         builder.send(None)
         return pbuf_type.load(builder)
     else:
-        future.resolve(UnexpectedMessageError(msg_type))
+        from trezor.messages.FailureType import UnexpectedMessage
+        future.resolve(FailureError(UnexpectedMessage, 'Unexpected message'))
         return _handle_registered_type(msg_type, data_len, session_id)
 
 
 def _handle_registered_type(msg_type, data_len, session_id):
-    genfunc, args = _workflow_genfuncs.get(
+    fallback = (_handle_unexpected_type, ())
-        msg_type, (_handle_unexpected_type, ()))
+    genfunc, args = _workflow_genfuncs.get(msg_type, fallback)
     return genfunc(msg_type, data_len, session_id, *args)
 
 
 def _handle_unexpected_type(msg_type, data_len, session_id):
-    log.info(__name__, 'skipping message %d of len %d' % (msg_type, data_len))
+    log.info(__name__, 'skipping message %d of len %d on session %d' %
+             (msg_type, data_len, session_id))
     try:
         while True:
             yield

src/trezor/workflows/request_pin.py

@@ -1,58 +1,37 @@
 from trezor import ui
 from trezor import wire
-from trezor import config
 from trezor.utils import unimport
 
-MANAGEMENT_APP = const(1)
 
-PASSPHRASE_PROTECT = (1)  # 0 | 1
+@unimport
-PIN_PROTECT = const(2)  # 0 | 1
+async def request_pin(session_id, *args, **kwargs):
-PIN = const(4)  # str
-
-
-def prompt_pin(*args, **kwargs):
-    from trezor.ui.pin import PinMatrix
-    from trezor.ui.confirm import ConfirmDialog, CONFIRMED
-
-    ui.clear()
-
-    matrix = PinMatrix(*args, **kwargs)
-    dialog = ConfirmDialog(matrix)
-    result = yield from dialog.wait()
-
-    return matrix.pin if result == CONFIRMED else None
-
-
-def request_pin(*args, **kwargs):
     from trezor.messages.ButtonRequest import ButtonRequest
     from trezor.messages.ButtonRequestType import ProtectCall
-    from trezor.messages.ButtonAck import ButtonAck
+    from trezor.messages.FailureType import PinCancelled
+    from trezor.messages.wire_types import ButtonAck
+    from trezor.ui.confirm import ConfirmDialog, CONFIRMED
+    from trezor.ui.pin import PinMatrix
 
-    ack = yield from wire.call(ButtonRequest(code=ProtectCall), ButtonAck)
+    await wire.reply_message(session_id,
-    pin = yield from prompt_pin(*args, **kwargs)
+                             ButtonRequest(code=ProtectCall),
+                             ButtonAck)
 
-    return pin
+    ui.clear()
+    matrix = PinMatrix(*args, **kwargs)
+    dialog = ConfirmDialog(matrix)
+    if await dialog != CONFIRMED:
+        raise wire.FailureError(PinCancelled, 'PIN cancelled')
+
+    return matrix.pin
 
 
-def change_pin():
+@unimport
-    pass
+async def request_new_pin(session_id):
-
-
-def protect_with_pin():
-    from trezor.messages.Failure import Failure
     from trezor.messages.FailureType import PinInvalid
-    from trezor.messages.FailureType import ActionCancelled
 
-    pin_protect = config.get(MANAGEMENT_APP, PIN_PROTECT)
+    pin_first = await request_pin(session_id)
-    if not pin_protect:
+    pin_again = await request_pin(session_id, 'Enter PIN again')
-        return
+    if pin_first != pin_again:
+        raise wire.FailureError(PinInvalid, 'PIN invalid')
 
-    entered_pin = yield from request_pin()
+    return pin_first
-    if entered_pin is None:
-        yield from wire.write(Failure(code=ActionCancelled, message='Cancelled'))
-        raise Exception('Cancelled')
-
-    stored_pin = config.get(MANAGEMENT_APP, PIN)
-    if stored_pin != entered_pin:
-        yield from wire.write(Failure(code=PinInvalid, message='PIN invalid'))
-        raise Exception('PIN invalid')