1 files changed, 31 insertions, 0 deletions
diff --git a/src/data_collection/processes/unix/user_table.rs b/src/data_collection/processes/unix/user_table.rs
new file mode 100644
index 00000000..6245a858
--- /dev/null
+++ b/src/data_collection/processes/unix/user_table.rs
@@ -0,0 +1,31 @@
+use hashbrown::HashMap;
+
+use crate::utils::error;
+
+#[derive(Debug, Default)]
+pub struct UserTable {
+    pub uid_user_mapping: HashMap<libc::uid_t, String>,
+}
+
+impl UserTable {
+    pub fn get_uid_to_username_mapping(&mut self, uid: libc::uid_t) -> error::Result<String> {
+        if let Some(user) = self.uid_user_mapping.get(&uid) {
+            Ok(user.clone())
+        } else {
+            // SAFETY: getpwuid returns a null pointer if no passwd entry is found for the uid
+            let passwd = unsafe { libc::getpwuid(uid) };
+
+            if passwd.is_null() {
+                Err(error::BottomError::QueryError("Missing passwd".into()))
+            } else {
+                // SAFETY: We return early if passwd is null.
+                let username = unsafe { std::ffi::CStr::from_ptr((*passwd).pw_name) }
+                    .to_str()?
+                    .to_string();
+                self.uid_user_mapping.insert(uid, username.clone());
+
+                Ok(username)
+            }
+        }
+    }
+}