hiffy: differentiate dead codes from error codes #472

hawkw · 2024-04-09T18:01:27Z

When invoking an IPC using humility-hiffy, the result is represented as a u32. Calling code typically will then attempt to turn that u32 back into the IPC interface's error code. However, if the server task that Hiffy called into has died, the u32 will instead be a dead code, which cannot be translated into a named error code using the Idol interface (or similar). Therefore, this branch updates humility hiffy to return an IpcError enum instead, which is either an error code or a dead code. This forces callers to differentiate between these cases, and not print out random integers when the server task has died.

When invoking an IPC using `humility-hiffy`, the result is represented as a `u32`. Calling code typically will then attempt to turn that `u32` back into the IPC interface's error code. However, if the server task that Hiffy called into has died, the `u32` will instead be a dead code, which cannot be translated into a named error code using the Idol interface (or similar). Therefore, this branch updates `humility hiffy` to return an `IpcError` enum instead, which is either an error code or a dead code. This forces callers to differentiate between these cases, and not print out random integers when the server task has died.

bcantrill

Looks good -- please bump the micro version as well!

mkeeter · 2024-04-10T19:18:27Z

cmd/rendmp/src/lib.rs

@@ -2274,12 +2274,13 @@ fn rendmp(context: &mut ExecutionContext) -> Result<()> {
        }
    };

-    let word_result = |result: &Result<Vec<u8>, u32>, what| -> Result<u32> {
+    let word_result = |result: &Result<Vec<u8>, IpcError>,
+                       what|


...are you okay, rustfmt?

humility-dump-agent/src/hiffy.rs

cmd/validate/src/lib.rs

humility-dump-agent/src/hiffy.rs

humility-hiffy/src/lib.rs

hawkw requested review from cbiffle and mkeeter April 9, 2024 18:01

hawkw force-pushed the eliza/hiffy-dead-codes branch from 4a5a42b to 9196449 Compare April 10, 2024 16:33

bcantrill approved these changes Apr 10, 2024

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