+static u32 alloced_secid = FREE_LIST_HEAD;
+static u32 free_list = FREE_LIST_HEAD;
+static unsigned long free_count;
+
+/*
+ * TODO: allow policy to reserve a secid range?
+ * TODO: add secid pinning
+ * TODO: use secid_update in label replace
+ */
+
+#define SECID_MAX U32_MAX
+
+/* TODO: mark free list as exceptional */
+static void *to_ptr(u32 secid)
+{
+ return (void *)
+ ((((unsigned long) secid) << RADIX_TREE_EXCEPTIONAL_SHIFT));
+}
+
+static u32 to_secid(void *ptr)
+{
+ return (u32) (((unsigned long) ptr) >> RADIX_TREE_EXCEPTIONAL_SHIFT);
+}
+
+
+/* TODO: tag free_list entries to mark them as different */
+static u32 __pop(struct aa_label *label)
+{
+ u32 secid = free_list;
+ void __rcu **slot;
+ void *entry;
+
+ if (free_list == FREE_LIST_HEAD)
+ return AA_SECID_INVALID;
+
+ slot = radix_tree_lookup_slot(&aa_secids_map, secid);
+ AA_BUG(!slot);
+ entry = radix_tree_deref_slot_protected(slot, &secid_lock);
+ free_list = to_secid(entry);
+ radix_tree_replace_slot(&aa_secids_map, slot, label);
+ free_count--;
+
+ return secid;
+}
+
+static void __push(u32 secid)
+{
+ void __rcu **slot;
+
+ slot = radix_tree_lookup_slot(&aa_secids_map, secid);
+ AA_BUG(!slot);
+ radix_tree_replace_slot(&aa_secids_map, slot, to_ptr(free_list));
+ free_list = secid;
+ free_count++;
+}
+
+static struct aa_label * __secid_update(u32 secid, struct aa_label *label)
+{
+ struct aa_label *old;
+ void __rcu **slot;
+
+ slot = radix_tree_lookup_slot(&aa_secids_map, secid);
+ AA_BUG(!slot);
+ old = radix_tree_deref_slot_protected(slot, &secid_lock);
+ radix_tree_replace_slot(&aa_secids_map, slot, label);
+
+ return old;
+}
+
+/**
+ * aa_secid_update - update a secid mapping to a new label
+ * @secid: secid to update
+ * @label: label the secid will now map to
+ */
+void aa_secid_update(u32 secid, struct aa_label *label)
+{
+ struct aa_label *old;
+ unsigned long flags;
+
+ spin_lock_irqsave(&secid_lock, flags);
+ old = __secid_update(secid, label);
+ spin_unlock_irqrestore(&secid_lock, flags);
+}
+
+/**
+ *
+ * see label for inverse aa_label_to_secid
+ */
+struct aa_label *aa_secid_to_label(u32 secid)
+{
+ struct aa_label *label;
+
+ rcu_read_lock();
+ label = radix_tree_lookup(&aa_secids_map, secid);
+ rcu_read_unlock();
+
+ return label;
+}
+
+int apparmor_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
+{
+ /* TODO: cache secctx and ref count so we don't have to recreate */
+ struct aa_label *label = aa_secid_to_label(secid);
+ int len;
+
+ AA_BUG(!secdata);
+ AA_BUG(!seclen);
+
+ if (!label)
+ return -EINVAL;
+
+ if (secdata)
+ len = aa_label_asxprint(secdata, root_ns, label,
+ FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
+ FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT,
+ GFP_ATOMIC);
+ else
+ len = aa_label_snxprint(NULL, 0, root_ns, label,
+ FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
+ FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT);
+ if (len < 0)
+ return -ENOMEM;
+
+ *seclen = len;
+
+ return 0;
+}
+
+
+int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
+{
+ struct aa_label *label;
+
+ label = aa_label_strn_parse(&root_ns->unconfined->label, secdata,
+ seclen, GFP_KERNEL, false, false);
+ if (IS_ERR(label))
+ return PTR_ERR(label);
+ *secid = label->secid;
+
+ return 0;
+}
+
+void apparmor_release_secctx(char *secdata, u32 seclen)
+{
+ kfree(secdata);
+}