--- a/pam/src/items.rs	Thu Jul 11 19:13:19 2019 -0700
+++ b/pam/src/items.rs	Sun Apr 24 03:42:11 2022 +0100
@@ -1,69 +1,88 @@
-use constants::{PamItemType, PAM_SERVICE, PAM_USER, PAM_USER_PROMPT, PAM_TTY, PAM_RUSER, PAM_RHOST,
-                PAM_AUTHTOK, PAM_OLDAUTHTOK};
-use module::PamItem;
-pub use conv::PamConv;
-
-
-pub struct PamService {}
-
-impl PamItem for PamService {
-    fn item_type() -> PamItemType {
-        PAM_SERVICE
-    }
-}
-
-pub struct PamUser {}
-
-impl PamItem for PamUser {
-    fn item_type() -> PamItemType {
-        PAM_USER
-    }
-}
-
-pub struct PamUserPrompt {}
-
-impl PamItem for PamUserPrompt {
-    fn item_type() -> PamItemType {
-        PAM_USER_PROMPT
-    }
+#[repr(u32)]
+pub enum ItemType {
+    /// The service name
+    Service = 1,
+    /// The user name
+    User = 2,
+    /// The tty name
+    Tty = 3,
+    /// The remote host name
+    RHost = 4,
+    /// The pam_conv structure
+    Conv = 5,
+    /// The authentication token (password)
+    AuthTok = 6,
+    /// The old authentication token
+    OldAuthTok = 7,
+    /// The remote user name
+    RUser = 8,
+    /// the prompt for getting a username
+    UserPrompt = 9,
+    /// app supplied function to override failure delays
+    FailDelay = 10,
+    /// X :display name
+    XDisplay = 11,
+    /// X :server authentication data
+    XAuthData = 12,
+    /// The type for pam_get_authtok
+    AuthTokType = 13,
 }
 
-pub struct PamTty {}
+// A type that can be requested by `pam::Handle::get_item`.
+pub trait Item {
+    /// The `repr(C)` type that is returned (by pointer) by the underlying `pam_get_item` function.
+    type Raw;
+
+    /// The `ItemType` for this type
+    fn type_id() -> ItemType;
 
-impl PamItem for PamTty {
-    fn item_type() -> PamItemType {
-        PAM_TTY
-    }
-}
+    /// The function to convert from the pointer to the C-representation to this safer wrapper type
+    ///
+    /// # Safety
+    ///
+    /// This function can assume the pointer is a valid pointer to a `Self::Raw` instance.
+    unsafe fn from_raw(raw: *const Self::Raw) -> Self;
 
-pub struct PamRUser {}
-
-impl PamItem for PamRUser {
-    fn item_type() -> PamItemType {
-        PAM_RUSER
-    }
+    /// The function to convert from this wrapper type to a C-compatible pointer.
+    fn into_raw(self) -> *const Self::Raw;
 }
 
-pub struct PamRHost {}
+macro_rules! cstr_item {
+    ($name:ident) => {
+        #[derive(Debug)]
+        pub struct $name<'s>(pub &'s std::ffi::CStr);
+
+        impl<'s> std::ops::Deref for $name<'s> {
+            type Target = &'s std::ffi::CStr;
+            fn deref(&self) -> &Self::Target {
+                &self.0
+            }
+        }
 
-impl PamItem for PamRHost {
-    fn item_type() -> PamItemType {
-        PAM_RHOST
-    }
+        impl<'s> Item for $name<'s> {
+            type Raw = libc::c_char;
+
+            fn type_id() -> ItemType {
+                ItemType::$name
+            }
+
+            unsafe fn from_raw(raw: *const Self::Raw) -> Self {
+                Self(std::ffi::CStr::from_ptr(raw))
+            }
+
+            fn into_raw(self) -> *const Self::Raw {
+                self.0.as_ptr()
+            }
+        }
+    };
 }
 
-pub struct PamAuthTok {}
-
-impl PamItem for PamAuthTok {
-    fn item_type() -> PamItemType {
-        PAM_AUTHTOK
-    }
-}
-
-pub struct PamOldAuthTok {}
-
-impl PamItem for PamOldAuthTok {
-    fn item_type() -> PamItemType {
-        PAM_OLDAUTHTOK
-    }
-}
+cstr_item!(Service);
+cstr_item!(User);
+cstr_item!(Tty);
+cstr_item!(RHost);
+// Conv
+cstr_item!(AuthTok);
+cstr_item!(OldAuthTok);
+cstr_item!(RUser);
+cstr_item!(UserPrompt);