Fix q_insert_head and q_insert_tail

Previously, the implementation stored string pointers directly, causing
issues when multiple elements shared the same memory reference. This
led to test failures checking whether strings were properly copied.

This fix ensures each queue element allocates and copies its own string,
preventing unintended modifications across elements.

Also, added proper cleanup in case of allocation failure.

Change-Id: Ic01c44fcab94b30eb8fbb31b7c85cd8e83c1c567

Author: yy214123

queue.c

@@ -39,7 +39,12 @@ bool q_insert_head(struct list_head *head, char *s)
     element_t *new_elem = malloc(sizeof(element_t));
     if (!new_elem)
         return false;
-    new_elem->value = s;
+    new_elem->value = malloc(strlen(s) + 1);
+    if (!new_elem->value) {
+        q_release_element(new_elem);
+        return false;
+    }
+    strlcpy(new_elem->value, s, strlen(s) + 1);
     list_add(&new_elem->list, head);
     return true;
 }
@@ -52,7 +57,12 @@ bool q_insert_tail(struct list_head *head, char *s)
     element_t *new_elem = malloc(sizeof(element_t));
     if (!new_elem)
         return false;
-    new_elem->value = s;
+    new_elem->value = malloc(strlen(s) + 1);
+    if (!new_elem->value) {
+        q_release_element(new_elem);
+        return false;
+    }
+    strlcpy(new_elem->value, s, strlen(s) + 1);
     list_add_tail(&new_elem->list, head);
     return true;
 }