Propagate guest exit codes and implement host-mediated time.sleep - #20
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Three behavioral fixes for python-agent-driver on Hyperlight: 1. Exception exit codes: PyRun_SimpleString swallowed exceptions. Replace with PyRun_String + manual exception handling in run_code_with_exceptions(). Non-zero exit codes reported to host via __hl_exit /dev/hcall side channel. 2. sys.exit(N) propagation: SystemExit was caught by CPython's internal handler which called exit() — Hyperlight's VmExit::Halt doesn't carry exit codes. Now intercepted before CPython handles it, code extracted and reported via __hl_exit. 3. time.sleep() was a no-op: Unikraft's cooperative scheduler on Hyperlight has no timer interrupt, so nanosleep returns immediately. Monkey-patch time.sleep during init to route through __hl_sleep host call, which blocks the host thread. Host side: Sandbox gains exit_code field (Arc<AtomicI32>), always registers __dispatch with __hl_exit and __hl_sleep handlers via register_internal_tools(). RunTiming exposes exit_code. pyhl binary exits with the guest's reported code. Signed-off-by: danbugs <danilochiarlone@gmail.com>
danbugs
marked this pull request as ready for review
May 13, 2026 02:06
danbugs
enabled auto-merge
May 13, 2026 02:06
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Linux Benchmarks
Details
| Benchmark suite | Current: 2270ef1 | Previous: 35c26ff | Ratio |
|---|---|---|---|
hello_world (median) |
20 ms |
20 ms |
1 |
pandas (median) |
100 ms |
100 ms |
1 |
density (per VM) |
6 MB |
6 MB |
1 |
snapshot (disk) |
648 MiB |
648 MiB |
1 |
This comment was automatically generated by workflow using github-action-benchmark.
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Windows Benchmarks
Details
| Benchmark suite | Current: 2270ef1 | Previous: 35c26ff | Ratio |
|---|---|---|---|
hello_world (median) |
237 ms |
281 ms |
0.84 |
pandas (median) |
819 ms |
983 ms |
0.83 |
density (per VM) |
6 MB |
6 MB |
1 |
snapshot (disk) |
673 MiB |
673 MiB |
1 |
This comment was automatically generated by workflow using github-action-benchmark.
Signed-off-by: danbugs <danilochiarlone@gmail.com>
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Summary
PyRun_SimpleString(which swallows exceptions) withPyRun_String+ manual exception handling.SystemExitcodes are extracted (e.g.sys.exit(42)→ exit code 42), other exceptions set exit code 1 with traceback printed. Non-zero codes reported to host via__hl_exit/dev/hcallside channel.time.sleep: Unikraft's cooperative scheduler on Hyperlight has no timer interrupt, sonanosleepreturns immediately. Monkey-patchtime.sleepduring init to route through__hl_sleephost call, which blocks the host thread for the requested duration.Sandboxgainslast_exit_code()/reset_exit_code()backed byArc<AtomicI32>.RunTimingexposesexit_code.pyhlbinary exits with the guest's reported code.