Update to wasi 0.11 (#253)

* Update to wasi 0.11

The main breaking change between v0.10 and v0.11 is that Error is
removed in favour of Errno. Unfortunately we can't create an Errno from
outside the wasi create so we're loosing some debug information for
errors.

I've opened an issue to add back such a constructor, see
<https://github.com/bytecodealliance/wasi/issues/64>.

* Use libc::strerror to get the error message on wasi

Since wasi v0.11 doesn't (yet) provided a way to create Errno, see
<https://github.com/bytecodealliance/wasi/issues/64>.

* Remove libc dependency for WASI

This does mean that we won't get an error message for the error type.

Cargo.toml

@@ -21,7 +21,7 @@ core = { version = "1.0", optional = true, package = "rustc-std-workspace-core"
 libc = { version = "0.2.120", default-features = false }
 
 [target.'cfg(target_os = "wasi")'.dependencies]
-wasi = "0.10"
+wasi = "0.11"
 
 [target.'cfg(all(target_arch = "wasm32", target_os = "unknown"))'.dependencies]
 wasm-bindgen = { version = "0.2.62", default-features = false, optional = true }

src/error.rs

@@ -109,10 +109,6 @@ cfg_if! {
             let idx = buf.iter().position(|&b| b == 0).unwrap_or(n);
             core::str::from_utf8(&buf[..idx]).ok()
         }
-    } else if #[cfg(target_os = "wasi")] {
-        fn os_err(errno: i32, _buf: &mut [u8]) -> Option<wasi::Error> {
-            wasi::Error::from_raw_error(errno as _)
-        }
     } else {
         fn os_err(_errno: i32, _buf: &mut [u8]) -> Option<&str> {
             None

src/wasi.rs

@@ -9,15 +9,11 @@
 //! Implementation for WASI
 use crate::Error;
 use core::num::NonZeroU32;
-use wasi::random_get;
+use wasi::wasi_snapshot_preview1::random_get;
 
 pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
-    unsafe {
-        random_get(dest.as_mut_ptr(), dest.len()).map_err(|e: wasi::Error| {
-            // convert wasi's Error into getrandom's NonZeroU32 error
-            // SAFETY: `wasi::Error` is `NonZeroU16` internally, so `e.raw_error()`
-            // will never return 0
-            NonZeroU32::new_unchecked(e.raw_error() as u32).into()
-        })
+    match unsafe { random_get(dest.as_mut_ptr() as i32, dest.len() as i32) } {
+        0 => Ok(()),
+        err => Err(unsafe { NonZeroU32::new_unchecked(err as u32) }.into()),
     }
 }