refactor(pal/hermit): make ENV a non-mutable static

Signed-off-by: Martin Kröning <martin.kroening@eonerc.rwth-aachen.de>

std/src/sys/pal/hermit/os.rs

@@ -68,21 +68,21 @@ pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
 }
 
-static mut ENV: Option<Mutex<HashMap<OsString, OsString>>> = None;
+static ENV: Mutex<Option<HashMap<OsString, OsString>>> = Mutex::new(None);
 
 pub fn init_environment(env: *const *const i8) {
-    unsafe {
-        ENV = Some(Mutex::new(HashMap::new()));
+    let mut guard = ENV.lock().unwrap();
+    let map = guard.insert(HashMap::new());
 
-        if env.is_null() {
-            return;
-        }
+    if env.is_null() {
+        return;
+    }
 
-        let mut guard = ENV.as_ref().unwrap().lock().unwrap();
+    unsafe {
         let mut environ = env;
         while !(*environ).is_null() {
             if let Some((key, value)) = parse(CStr::from_ptr(*environ).to_bytes()) {
-                guard.insert(key, value);
+                map.insert(key, value);
             }
             environ = environ.add(1);
         }
@@ -154,30 +154,26 @@ impl Iterator for Env {
 /// Returns a vector of (variable, value) byte-vector pairs for all the
 /// environment variables of the current process.
 pub fn env() -> Env {
-    unsafe {
-        let guard = ENV.as_ref().unwrap().lock().unwrap();
-        let mut result = Vec::new();
+    let guard = ENV.lock().unwrap();
+    let env = guard.as_ref().unwrap();
 
-        for (key, value) in guard.iter() {
-            result.push((key.clone(), value.clone()));
-        }
+    let result = env.iter().map(|(key, value)| (key.clone(), value.clone())).collect::<Vec<_>>();
 
-        return Env { iter: result.into_iter() };
-    }
+    Env { iter: result.into_iter() }
 }
 
 pub fn getenv(k: &OsStr) -> Option<OsString> {
-    unsafe { ENV.as_ref().unwrap().lock().unwrap().get_mut(k).cloned() }
+    ENV.lock().unwrap().as_ref().unwrap().get(k).cloned()
 }
 
 pub unsafe fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
     let (k, v) = (k.to_owned(), v.to_owned());
-    ENV.as_ref().unwrap().lock().unwrap().insert(k, v);
+    ENV.lock().unwrap().as_mut().unwrap().insert(k, v);
     Ok(())
 }
 
 pub unsafe fn unsetenv(k: &OsStr) -> io::Result<()> {
-    ENV.as_ref().unwrap().lock().unwrap().remove(k);
+    ENV.lock().unwrap().as_mut().unwrap().remove(k);
     Ok(())
 }