wasi-common: port to use wiggle::Trap

crates/wasi-common/src/snapshots/wasi_snapshot_preview1.rs

@@ -714,10 +714,13 @@ impl<'a> WasiSnapshotPreview1 for WasiCtx {
         Ok(nevents)
     }
 
-    fn proc_exit(&self, _rval: types::Exitcode) -> std::result::Result<(), ()> {
-        // proc_exit is special in that it's expected to unwind the stack, which
-        // typically requires runtime-specific logic.
-        unimplemented!("runtimes are expected to override this implementation")
+    fn proc_exit(&self, status: types::Exitcode) -> wiggle::Trap {
+        // Check that the status is within WASI's range.
+        if status < 126 {
+            wiggle::Trap::I32(status as i32)
+        } else {
+            wiggle::Trap::String("exit with invalid exit status outside of [0..126)".to_owned())
+        }
     }
 
     fn proc_raise(&self, _sig: types::Signal) -> Result<()> {

crates/wasi-common/src/snapshots/wasi_unstable.rs

@@ -23,7 +23,7 @@ impl types::GuestErrorConversion for WasiCtx {
 }
 
 impl types::UserErrorConversion for WasiCtx {
-    fn errno_from_error(&self, e: Error) -> Result<Errno, String> {
+    fn errno_from_error(&self, e: Error) -> Result<Errno, wiggle::Trap> {
         tracing::debug!("Error: {:?}", e);
         Ok(e.into())
     }
@@ -346,7 +346,7 @@ impl wasi_unstable::WasiUnstable for WasiCtx {
         Ok(nevents)
     }
 
-    fn proc_exit(&self, rval: Exitcode) -> Result<(), ()> {
+    fn proc_exit(&self, rval: Exitcode) -> wiggle::Trap {
         WasiSnapshotPreview1::proc_exit(self, rval)
     }
 

crates/wasi-common/src/wasi.rs

@@ -23,7 +23,7 @@ impl types::GuestErrorConversion for WasiCtx {
 }
 
 impl types::UserErrorConversion for WasiCtx {
-    fn errno_from_error(&self, e: Error) -> Result<Errno, String> {
+    fn errno_from_error(&self, e: Error) -> Result<Errno, wiggle::Trap> {
         debug!("Error: {:?}", e);
         Ok(e.into())
     }