BlackMark
142de8775d
The post-prompt settle loop in _handshake had no deadline, so a target that never falls quiet — a board stuck in a reset loop, whose UART-reset garbage carries a stray prompt byte — spun the tool forever. Bound it by the handshake deadline; a real loader still settles on its first quiet read. Regression: test/test_handshake.py (flood terminates, valid loader still connects). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
105 lines
3.1 KiB
Python
105 lines
3.1 KiB
Python
#!/usr/bin/env python3
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"""Host-tool activation handshake: it must not hang on a flooding target.
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`_handshake` drains the line after it sees a prompt, to absorb a real loader's
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trailing bytes before it asks for the identity. That drain must be bounded: a
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target that never falls quiet — a board stuck in a reset loop presents exactly
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this, ~60 reboots/s of UART-reset garbage in which a stray 0x2b reads as a
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prompt — otherwise spins the tool forever. Regression for that hang, plus a
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control that a well-behaved loader still connects.
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Stdlib only; run with `python test/test_handshake.py`.
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"""
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import importlib.util
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import pathlib
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import threading
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import time
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PB = pathlib.Path(__file__).resolve().parents[1] / "pureboot.py"
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_spec = importlib.util.spec_from_file_location("pureboot", PB)
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pb = importlib.util.module_from_spec(_spec)
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_spec.loader.exec_module(pb)
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P = F = 0
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def check(name, ok):
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global P, F
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P, F = P + (1 if ok else 0), F + (0 if ok else 1)
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print(f" [{'PASS' if ok else 'FAIL'}] {name}")
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class FloodPort:
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"""A line that never falls quiet: read_available always returns bytes, and
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they contain a prompt. No identity ever completes."""
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def flush_input(self):
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pass
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def write(self, data):
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pass
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def read_available(self, wait):
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time.sleep(0.01) # a real read waits; keep the busy loop off a core
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return b"+\x00\xff"
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def read_exact(self, count, timeout):
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raise pb.Error("no identity")
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class LoaderPort:
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"""A well-behaved pureboot 5: one prompt to the knock, then quiet, then the
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slim identity (version 5 + m328p signature) and a closing prompt."""
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def __init__(self):
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self.reads = self.exacts = 0
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def flush_input(self):
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pass
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def write(self, data):
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pass
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def read_available(self, wait):
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self.reads += 1
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return b"+" if self.reads == 1 else b"" # prompt once, then settle quiet
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def read_exact(self, count, timeout):
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self.exacts += 1
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return b"\x05\x1e\x95\x0f" if self.exacts == 1 else b"+" # identity, then prompt
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def terminates(port, wait, budget):
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"""Run connect_autobaud in a thread; True if it returns/raises within
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`budget` seconds rather than hanging."""
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done = threading.Event()
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def run():
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try:
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pb.Loader(port).connect_autobaud(wait)
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except Exception:
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pass
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finally:
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done.set()
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threading.Thread(target=run, daemon=True).start()
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return done.wait(budget)
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def main():
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# the hang: a flooding target must not spin the drain forever. With wait=0.5
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# the whole handshake has to give up well inside a few seconds.
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check("flooding target: handshake terminates, drain is bounded",
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terminates(FloodPort(), wait=0.5, budget=4.0))
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# the control: a real loader still connects and reads identity.
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info = pb.Loader(LoaderPort()).connect_autobaud(2.0)
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check("well-behaved loader still connects (version 5)", info.version == 5)
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print(f"\n {P} passed, {F} failed")
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return 1 if F else 0
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if __name__ == "__main__":
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raise SystemExit(main())
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