tty: Build tty.wasm

Author: oech3

.github/workflows/wasi.yml

@@ -37,7 +37,7 @@ jobs:
         CARGO_TARGET_WASM32_WASIP1_RUNNER: wasmtime
       run: |
         # Get all utilities and exclude ones that don't compile for wasm32-wasip1
-        EXCLUDE="dd|df|du|env|expr|mktemp|more|tac|test|tty"
+        EXCLUDE="dd|df|du|env|expr|mktemp|more|tac|test"
         UTILS=$(./util/show-utils.sh | tr ' ' '\n' | grep -vE "^($EXCLUDE)$" | sed 's/^/-p uu_/' | tr '\n' ' ')
         cargo test --target wasm32-wasip1 --no-default-features $UTILS
     - name: Run integration tests via wasmtime

Cargo.toml

@@ -235,6 +235,7 @@ feat_wasm = [
   "true",
   "truncate",
   "tsort",
+  "tty",
   "uname",
   "unexpand",
   "uniq",

src/uu/tty/src/tty.rs

@@ -49,7 +49,14 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         set_exit_code(1);
         writeln!(stdout, "{}", translate!("tty-not-a-tty"))
     };
-
+    #[cfg(target_os = "wasi")]
+    let write_result = if std::io::stdin().is_terminal() {
+        // maximize compatibility
+        writeln!(stdout, r"/dev/tty")
+    } else {
+        set_exit_code(1);
+        writeln!(stdout, "{}", translate!("tty-not-a-tty"))
+    };
     #[cfg(target_os = "windows")]
     let write_result = if std::io::stdin().is_terminal() {
         writeln!(stdout, r"\\.\CON")