Merge pull request #2140 from bytecodealliance/pch/wasi_error_handling

wasi-common: refactor error types

crates/wasi-common/src/wasi.rs

@@ -1,15 +1,13 @@
-//! Types and constants shared between 32-bit and 64-bit wasi. Types involving
-//! pointer or `usize`-sized data are excluded here, so this file only contains
-//! fixed-size types, so it's host/target independent.
-use crate::WasiCtx;
+use crate::{Error, Result, WasiCtx};
+use tracing::debug;
 
 wiggle::from_witx!({
     witx: ["$WASI_ROOT/phases/snapshot/witx/wasi_snapshot_preview1.witx"],
     ctx: WasiCtx,
+    errors: { errno => Error },
 });
 
-pub use types::Errno;
-pub type Result<T> = std::result::Result<T, Errno>;
+use types::Errno;
 
 impl wiggle::GuestErrorType for Errno {
     fn success() -> Self {
@@ -19,9 +17,54 @@ impl wiggle::GuestErrorType for Errno {
 
 impl types::GuestErrorConversion for WasiCtx {
     fn into_errno(&self, e: wiggle::GuestError) -> Errno {
-        eprintln!("Guest error: {:?}", e);
-        // TODO proper error mapping
-        Errno::Inval
+        debug!("Guest error: {:?}", e);
+        e.into()
+    }
+}
+
+impl types::UserErrorConversion for WasiCtx {
+    fn errno_from_error(&self, e: Error) -> Errno {
+        debug!("Error: {:?}", e);
+        e.into()
+    }
+}
+
+impl From<Error> for Errno {
+    fn from(e: Error) -> Errno {
+        match e {
+            Error::Guest(e) => e.into(),
+            Error::TryFromInt(_) => Errno::Overflow,
+            Error::Utf8(_) => Errno::Ilseq,
+            Error::UnexpectedIo(_) => Errno::Io,
+            Error::GetRandom(_) => Errno::Io,
+            Error::TooBig => Errno::TooBig,
+            Error::Acces => Errno::Acces,
+            Error::Badf => Errno::Badf,
+            Error::Busy => Errno::Busy,
+            Error::Exist => Errno::Exist,
+            Error::Fault => Errno::Fault,
+            Error::Fbig => Errno::Fbig,
+            Error::Ilseq => Errno::Ilseq,
+            Error::Inval => Errno::Inval,
+            Error::Io => Errno::Io,
+            Error::Isdir => Errno::Isdir,
+            Error::Loop => Errno::Loop,
+            Error::Mfile => Errno::Mfile,
+            Error::Mlink => Errno::Mlink,
+            Error::Nametoolong => Errno::Nametoolong,
+            Error::Nfile => Errno::Nfile,
+            Error::Noent => Errno::Noent,
+            Error::Nomem => Errno::Nomem,
+            Error::Nospc => Errno::Nospc,
+            Error::Notdir => Errno::Notdir,
+            Error::Notempty => Errno::Notempty,
+            Error::Notsup => Errno::Notsup,
+            Error::Overflow => Errno::Overflow,
+            Error::Pipe => Errno::Pipe,
+            Error::Perm => Errno::Perm,
+            Error::Spipe => Errno::Spipe,
+            Error::Notcapable => Errno::Notcapable,
+        }
     }
 }
 
@@ -45,24 +88,6 @@ impl From<wiggle::GuestError> for Errno {
     }
 }
 
-impl From<std::convert::Infallible> for Errno {
-    fn from(_err: std::convert::Infallible) -> Self {
-        unreachable!()
-    }
-}
-
-impl From<std::num::TryFromIntError> for Errno {
-    fn from(_err: std::num::TryFromIntError) -> Self {
-        Self::Overflow
-    }
-}
-
-impl From<std::str::Utf8Error> for Errno {
-    fn from(_err: std::str::Utf8Error) -> Self {
-        Self::Ilseq
-    }
-}
-
 impl From<std::fs::FileType> for types::Filetype {
     fn from(ftype: std::fs::FileType) -> Self {
         if ftype.is_file() {