1 files changed, 148 insertions, 0 deletions
diff --git a/security/selinux/ss/hashtab.h b/security/selinux/ss/hashtab.h
new file mode 100644
index 000000000..043a773bf
--- /dev/null
+++ b/security/selinux/ss/hashtab.h
@@ -0,0 +1,148 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A hash table (hashtab) maintains associations between
+ * key values and datum values.  The type of the key values
+ * and the type of the datum values is arbitrary.  The
+ * functions for hash computation and key comparison are
+ * provided by the creator of the table.
+ *
+ * Author : Stephen Smalley, <sds@tycho.nsa.gov>
+ */
+#ifndef _SS_HASHTAB_H_
+#define _SS_HASHTAB_H_
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+
+#define HASHTAB_MAX_NODES	U32_MAX
+
+struct hashtab_key_params {
+	u32 (*hash)(const void *key);	/* hash function */
+	int (*cmp)(const void *key1, const void *key2);
+					/* key comparison function */
+};
+
+struct hashtab_node {
+	void *key;
+	void *datum;
+	struct hashtab_node *next;
+};
+
+struct hashtab {
+	struct hashtab_node **htable;	/* hash table */
+	u32 size;			/* number of slots in hash table */
+	u32 nel;			/* number of elements in hash table */
+};
+
+struct hashtab_info {
+	u32 slots_used;
+	u32 max_chain_len;
+};
+
+/*
+ * Initializes a new hash table with the specified characteristics.
+ *
+ * Returns -ENOMEM if insufficient space is available or 0 otherwise.
+ */
+int hashtab_init(struct hashtab *h, u32 nel_hint);
+
+int __hashtab_insert(struct hashtab *h, struct hashtab_node **dst,
+		     void *key, void *datum);
+
+/*
+ * Inserts the specified (key, datum) pair into the specified hash table.
+ *
+ * Returns -ENOMEM on memory allocation error,
+ * -EEXIST if there is already an entry with the same key,
+ * -EINVAL for general errors or
+  0 otherwise.
+ */
+static inline int hashtab_insert(struct hashtab *h, void *key, void *datum,
+				 struct hashtab_key_params key_params)
+{
+	u32 hvalue;
+	struct hashtab_node *prev, *cur;
+
+	cond_resched();
+
+	if (!h->size || h->nel == HASHTAB_MAX_NODES)
+		return -EINVAL;
+
+	hvalue = key_params.hash(key) & (h->size - 1);
+	prev = NULL;
+	cur = h->htable[hvalue];
+	while (cur) {
+		int cmp = key_params.cmp(key, cur->key);
+
+		if (cmp == 0)
+			return -EEXIST;
+		if (cmp < 0)
+			break;
+		prev = cur;
+		cur = cur->next;
+	}
+
+	return __hashtab_insert(h, prev ? &prev->next : &h->htable[hvalue],
+				key, datum);
+}
+
+/*
+ * Searches for the entry with the specified key in the hash table.
+ *
+ * Returns NULL if no entry has the specified key or
+ * the datum of the entry otherwise.
+ */
+static inline void *hashtab_search(struct hashtab *h, const void *key,
+				   struct hashtab_key_params key_params)
+{
+	u32 hvalue;
+	struct hashtab_node *cur;
+
+	if (!h->size)
+		return NULL;
+
+	hvalue = key_params.hash(key) & (h->size - 1);
+	cur = h->htable[hvalue];
+	while (cur) {
+		int cmp = key_params.cmp(key, cur->key);
+
+		if (cmp == 0)
+			return cur->datum;
+		if (cmp < 0)
+			break;
+		cur = cur->next;
+	}
+	return NULL;
+}
+
+/*
+ * Destroys the specified hash table.
+ */
+void hashtab_destroy(struct hashtab *h);
+
+/*
+ * Applies the specified apply function to (key,datum,args)
+ * for each entry in the specified hash table.
+ *
+ * The order in which the function is applied to the entries
+ * is dependent upon the internal structure of the hash table.
+ *
+ * If apply returns a non-zero status, then hashtab_map will cease
+ * iterating through the hash table and will propagate the error
+ * return to its caller.
+ */
+int hashtab_map(struct hashtab *h,
+		int (*apply)(void *k, void *d, void *args),
+		void *args);
+
+int hashtab_duplicate(struct hashtab *new, struct hashtab *orig,
+		int (*copy)(struct hashtab_node *new,
+			struct hashtab_node *orig, void *args),
+		int (*destroy)(void *k, void *d, void *args),
+		void *args);
+
+/* Fill info with some hash table statistics */
+void hashtab_stat(struct hashtab *h, struct hashtab_info *info);
+
+#endif	/* _SS_HASHTAB_H */