wasi-cap-std-sync: use std::io::Std{in,out,err} to impl {read,write}_vectored (#6825)

* add new wasi-test printing unicode on stdout

there's not yet a way to show this test is actually doing what we
intend, I'm using CI to see how this runs on all platforms

Reported in #6824

prtest:full

* cap-std-sync: use std::io::Std{in,out,err}'s {read,write}_vectored directly

instead of using AsFilelike to view these as a File.

This means we also have to use std's mutexes to access these descriptors,
which also seems like a good idea.

We believe will fix unicode output on windows issues:
https://github.com/bytecodealliance/wasmtime/issues/6824

crates/test-programs/tests/wasi-cap-std-sync.rs

@@ -291,3 +291,7 @@ fn unlink_file_trailing_slashes() {
 fn path_open_preopen() {
     run("path_open_preopen", true).unwrap()
 }
+#[test_log::test]
+fn unicode_output() {
+    run("unicode_output", true).unwrap()
+}

crates/test-programs/tests/wasi-preview1-host-in-preview2.rs

@@ -335,3 +335,7 @@ async fn unlink_file_trailing_slashes() {
 async fn path_open_preopen() {
     run("path_open_preopen", false).await.unwrap()
 }
+#[test_log::test(tokio::test(flavor = "multi_thread"))]
+async fn unicode_output() {
+    run("unicode_output", true).await.unwrap()
+}

crates/test-programs/tests/wasi-preview2-components-sync.rs

@@ -312,3 +312,7 @@ fn unlink_file_trailing_slashes() {
 fn path_open_preopen() {
     run("path_open_preopen", false).unwrap()
 }
+#[test_log::test]
+fn unicode_output() {
+    run("unicode_output", true).unwrap()
+}

crates/test-programs/tests/wasi-preview2-components.rs

@@ -320,3 +320,7 @@ async fn unlink_file_trailing_slashes() {
 async fn path_open_preopen() {
     run("path_open_preopen", false).await.unwrap()
 }
+#[test_log::test(tokio::test(flavor = "multi_thread"))]
+async fn unicode_output() {
+    run("unicode_output", true).await.unwrap()
+}

crates/test-programs/tests/wasi-tokio.rs

@@ -297,3 +297,7 @@ async fn unlink_file_trailing_slashes() {
 async fn path_open_preopen() {
     run("path_open_preopen", true).await.unwrap()
 }
+#[test_log::test(tokio::test(flavor = "multi_thread"))]
+async fn unicode_output() {
+    run("unicode_output", true).await.unwrap()
+}

crates/test-programs/wasi-tests/src/bin/unicode_output.rs

@@ -0,0 +1,15 @@
+use wasi_tests::STDOUT_FD;
+fn main() {
+    let text = "مرحبا بكم\n";
+
+    let ciovecs = [wasi::Ciovec {
+        buf: text.as_bytes().as_ptr(),
+        buf_len: text.as_bytes().len(),
+    }];
+    let written = unsafe { wasi::fd_write(STDOUT_FD, &ciovecs) }.expect("write succeeds");
+    assert_eq!(
+        written,
+        text.as_bytes().len(),
+        "full contents should be written"
+    );
+}

crates/wasi-common/cap-std-sync/src/stdio.rs

@@ -1,10 +1,8 @@
 use crate::file::convert_systimespec;
 use fs_set_times::SetTimes;
-use io_lifetimes::AsFilelike;
 use is_terminal::IsTerminal;
 use std::any::Any;
 use std::convert::TryInto;
-use std::fs::File;
 use std::io;
 use std::io::{Read, Write};
 use system_interface::io::ReadReady;
@@ -50,7 +48,7 @@ impl WasiFile for Stdin {
         }
     }
     async fn read_vectored<'a>(&self, bufs: &mut [io::IoSliceMut<'a>]) -> Result<u64, Error> {
-        let n = (&*self.0.as_filelike_view::<File>()).read_vectored(bufs)?;
+        let n = self.0.lock().read_vectored(bufs)?;
         Ok(n.try_into().map_err(|_| Error::range())?)
     }
     async fn read_vectored_at<'a>(
@@ -128,7 +126,7 @@ macro_rules! wasi_file_write_impl {
                 Ok(FdFlags::APPEND)
             }
             async fn write_vectored<'a>(&self, bufs: &[io::IoSlice<'a>]) -> Result<u64, Error> {
-                let n = (&*self.0.as_filelike_view::<File>()).write_vectored(bufs)?;
+                let n = self.0.lock().write_vectored(bufs)?;
                 Ok(n.try_into().map_err(|_| {
                     Error::range().context("converting write_vectored total length")
                 })?)