--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/memory.rs	Wed May 21 19:00:51 2025 -0400
@@ -0,0 +1,35 @@
+//! Utility functions for dealing with memory copying and stuff.
+
+use crate::ErrorCode;
+use libc::c_char;
+use std::ffi::{CStr, CString};
+
+/// Safely converts a `&str` option to a `CString` option.
+pub fn option_cstr(prompt: Option<&str>) -> crate::Result<Option<CString>> {
+    prompt
+        .map(CString::new)
+        .transpose()
+        .map_err(|_| ErrorCode::ConversationError)
+}
+
+/// Gets the pointer to the given CString, or a null pointer if absent.
+pub fn prompt_ptr(prompt: Option<&CString>) -> *const c_char {
+    match prompt {
+        Some(c_str) => c_str.as_ptr(),
+        None => std::ptr::null(),
+    }
+}
+
+/// Creates an owned copy of a string that is returned from a
+/// <code>pam_get_<var>whatever</var></code> function.
+pub fn copy_pam_string(result_ptr: *const c_char) -> crate::Result<String> {
+    // We really shouldn't get a null pointer back here, but if we do, return nothing.
+    if result_ptr.is_null() {
+        return Ok(String::new());
+    }
+    let bytes = unsafe { CStr::from_ptr(result_ptr) };
+    bytes
+        .to_str()
+        .map(String::from)
+        .map_err(|_| ErrorCode::ConversationError)
+}