wasi:[email protected]: Add tests for errors during open

Author: wingo

tests/rust/wasm32-wasip3/src/bin/filesystem-open-errors.json

@@ -0,0 +1,3 @@
+{
+    "dirs": ["fs-tests.dir"]
+}

tests/rust/wasm32-wasip3/src/bin/filesystem-open-errors.rs

@@ -0,0 +1,69 @@
+use std::process;
+extern crate wit_bindgen;
+
+wit_bindgen::generate!({
+    inline: r"
+  package test:test;
+
+  world test {
+      include wasi:filesystem/[email protected];
+      include wasi:cli/[email protected];
+  }
+",
+    additional_derives: [PartialEq, Eq, Hash, Clone],
+    // Work around https://github.com/bytecodealliance/wasm-tools/issues/2285.
+    features:["clocks-timezone"],
+    generate_all
+});
+
+use wasi::filesystem::types::Descriptor;
+use wasi::filesystem::types::{DescriptorFlags, ErrorCode, OpenFlags, PathFlags};
+
+async fn test_open_errors(dir: &Descriptor) {
+    let open = |flags: PathFlags, path: &str| -> _ {
+        dir.open_at(
+            flags,
+            path.to_string(),
+            OpenFlags::empty(),
+            DescriptorFlags::READ,
+        )
+    };
+    let open_r = |path: &str| open(PathFlags::empty(), path);
+    let open_r_follow = |path: &str| open(PathFlags::SYMLINK_FOLLOW, path);
+    // open-at: async func(path-flags: path-flags, path: string, open-flags: open-flags, %flags: descriptor-flags) -> result<descriptor, error-code>;
+    assert_eq!(open_r("").await.expect_err("open"),
+               ErrorCode::NoEntry);
+    assert_eq!(
+        open_r("..").await.expect_err("open .."),
+        ErrorCode::NotPermitted
+    );
+    assert_eq!(
+        open_r_follow("parent").await.expect_err("open parent"),
+        ErrorCode::NotPermitted
+    );
+    assert_eq!(
+        open_r("/").await.expect_err("open /"),
+        ErrorCode::NotPermitted
+    );
+}
+
+struct Component;
+export!(Component);
+impl exports::wasi::cli::run::Guest for Component {
+    async fn run() -> Result<(), ()> {
+        match &wasi::filesystem::preopens::get_directories()[..] {
+            [(dir, dirname)] if dirname == "fs-tests.dir" => {
+                test_open_errors(dir).await;
+            }
+            [..] => {
+                eprintln!("usage: run with one open dir named 'fs-tests.dir'");
+                process::exit(1)
+            }
+        };
+        Ok(())
+    }
+}
+
+fn main() {
+    unreachable!("main is a stub");
+}