env/stbuf: better handling of the errors

src/uu/env/src/env.rs

@@ -539,16 +539,19 @@ impl EnvAppData {
                 }
                 return Err(exit.code().unwrap().into());
             }
-            Err(ref err)
-                if (err.kind() == io::ErrorKind::NotFound)
-                    || (err.kind() == io::ErrorKind::InvalidInput) =>
-            {
-                return Err(self.make_error_no_such_file_or_dir(prog.deref()));
-            }
-            Err(e) => {
-                uucore::show_error!("unknown error: {:?}", e);
-                return Err(126.into());
-            }
+            Err(ref err) => match err.kind() {
+                io::ErrorKind::NotFound | io::ErrorKind::InvalidInput => {
+                    return Err(self.make_error_no_such_file_or_dir(prog.deref()));
+                }
+                io::ErrorKind::PermissionDenied => {
+                    uucore::show_error!("{}: Permission denied", prog.quote());
+                    return Err(126.into());
+                }
+                _ => {
+                    uucore::show_error!("unknown error: {:?}", err);
+                    return Err(126.into());
+                }
+            },
             Ok(_) => (),
         }
         Ok(())

src/uu/stdbuf/src/stdbuf.rs

@@ -157,9 +157,24 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     set_command_env(&mut command, "_STDBUF_E", &options.stderr);
     command.args(command_params);
 
-    let mut process = command
-        .spawn()
-        .map_err_context(|| "failed to execute process".to_string())?;
+    const EXEC_ERROR: &str = "failed to execute process:";
+    let mut process = match command.spawn() {
+        Ok(p) => p,
+        Err(e) => {
+            return match e.kind() {
+                std::io::ErrorKind::PermissionDenied => Err(USimpleError::new(
+                    126,
+                    format!("{EXEC_ERROR} Permission denied"),
+                )),
+                std::io::ErrorKind::NotFound => Err(USimpleError::new(
+                    127,
+                    format!("{EXEC_ERROR} No such file or directory"),
+                )),
+                _ => Err(USimpleError::new(1, format!("{EXEC_ERROR} {}", e))),
+            }
+        }
+    };
+
     let status = process.wait().map_err_context(String::new)?;
     match status.code() {
         Some(i) => {

tests/by-util/test_env.rs

@@ -80,6 +80,15 @@ fn test_env_version() {
         .stdout_contains(util_name!());
 }
 
+#[test]
+fn test_env_permissions() {
+    new_ucmd!()
+        .arg(".")
+        .fails()
+        .code_is(126)
+        .stderr_is("env: '.': Permission denied\n");
+}
+
 #[test]
 fn test_echo() {
     #[cfg(target_os = "windows")]

tests/by-util/test_stdbuf.rs

@@ -10,6 +10,26 @@ fn invalid_input() {
     new_ucmd!().arg("-/").fails().code_is(125);
 }
 
+#[test]
+fn test_permission() {
+    new_ucmd!()
+        .arg("-o1")
+        .arg(".")
+        .fails()
+        .code_is(126)
+        .stderr_contains("Permission denied");
+}
+
+#[test]
+fn test_no_such() {
+    new_ucmd!()
+        .arg("-o1")
+        .arg("no_such")
+        .fails()
+        .code_is(127)
+        .stderr_contains("No such file or directory");
+}
+
 #[cfg(all(not(target_os = "windows"), not(target_os = "openbsd")))]
 #[test]
 fn test_stdbuf_unbuffered_stdout() {