--- a/src/environ.rs	Tue Jun 24 14:54:47 2025 -0400
+++ b/src/environ.rs	Tue Jun 24 17:08:01 2025 -0400
@@ -3,26 +3,31 @@
 //! PAM modules can set environment variables to apply to a user session.
 //! This module manages the interface for doing all of that.
 
+use crate::constants::Result;
 use std::ffi::{OsStr, OsString};
 
 /// A key/value map for environment variables, as [`OsString`]s.
 ///
 /// This is a limited subset of what [`HashMap`](std::collections::HashMap)
 /// can do. Notably, we do *not* support mutable iteration.
-pub trait EnvironMap {
+pub trait EnvironMap<'a> {
     /// Gets the environment variable of the given key.
-    fn get(&self, val: &OsStr) -> Option<&OsStr>;
+    fn get(&self, key: impl AsRef<OsStr>) -> Option<OsString>;
 
     /// Iterates over the key/value pairs of the environment.
-    fn iter(&self) -> impl Iterator<Item = (&OsStr, &OsStr)>;
+    fn iter(&self) -> Result<impl Iterator<Item = (OsString, OsString)>>;
 }
 
-pub trait EnvironMapMut: EnvironMap {
+pub trait EnvironMapMut<'a>: EnvironMap<'a> {
     /// Sets the environment variable with the given key,
     /// returning the old one if present.
-    fn insert(&mut self, key: &OsStr, val: &OsStr) -> Option<OsString>;
+    fn insert(
+        &mut self,
+        key: impl AsRef<OsStr>,
+        val: impl AsRef<OsStr>,
+    ) -> Result<Option<OsString>>;
 
     /// Removes the environment variable from the map, returning its old value
     /// if present.
-    fn remove(&mut self, key: &OsStr) -> Option<OsString>;
+    fn remove(&mut self, key: impl AsRef<OsStr>) -> Result<Option<OsString>>;
 }