tools/lib/bpf/hashmap.h

Source file repositories/reference/linux-study-clean/tools/lib/bpf/hashmap.h

File Facts

System
Linux kernel
Corpus path
tools/lib/bpf/hashmap.h
Extension
.h
Size
6934 bytes
Lines
209
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct hashmap_entry {
	union {
		long key;
		const void *pkey;
	};
	union {
		long value;
		void *pvalue;
	};
	struct hashmap_entry *next;
};

struct hashmap {
	hashmap_hash_fn hash_fn;
	hashmap_equal_fn equal_fn;
	void *ctx;

	struct hashmap_entry **buckets;
	size_t cap;
	size_t cap_bits;
	size_t sz;
};

void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
		   hashmap_equal_fn equal_fn, void *ctx);
struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
			     hashmap_equal_fn equal_fn,
			     void *ctx);
void hashmap__clear(struct hashmap *map);
void hashmap__free(struct hashmap *map);

size_t hashmap__size(const struct hashmap *map);
size_t hashmap__capacity(const struct hashmap *map);

/*
 * Hashmap insertion strategy:
 * - HASHMAP_ADD - only add key/value if key doesn't exist yet;
 * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
 *   update value;
 * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
 *   nothing and return -ENOENT;
 * - HASHMAP_APPEND - always add key/value pair, even if key already exists.
 *   This turns hashmap into a multimap by allowing multiple values to be
 *   associated with the same key. Most useful read API for such hashmap is
 *   hashmap__for_each_key_entry() iteration. If hashmap__find() is still
 *   used, it will return last inserted key/value entry (first in a bucket
 *   chain).
 */
enum hashmap_insert_strategy {
	HASHMAP_ADD,
	HASHMAP_SET,
	HASHMAP_UPDATE,
	HASHMAP_APPEND,
};

#define hashmap_cast_ptr(p) ({								\
	_Static_assert((__builtin_constant_p((p)) ? (p) == NULL : 0) ||			\
				sizeof(*(p)) == sizeof(long),				\
		       #p " pointee should be a long-sized integer or a pointer");	\
	(long *)(p);									\
})

/*
 * hashmap__insert() adds key/value entry w/ various semantics, depending on
 * provided strategy value. If a given key/value pair replaced already
 * existing key/value pair, both old key and old value will be returned
 * through old_key and old_value to allow calling code do proper memory
 * management.
 */
int hashmap_insert(struct hashmap *map, long key, long value,
		   enum hashmap_insert_strategy strategy,
		   long *old_key, long *old_value);

#define hashmap__insert(map, key, value, strategy, old_key, old_value) \
	hashmap_insert((map), (long)(key), (long)(value), (strategy),  \
		       hashmap_cast_ptr(old_key),		       \
		       hashmap_cast_ptr(old_value))

#define hashmap__add(map, key, value) \
	hashmap__insert((map), (key), (value), HASHMAP_ADD, NULL, NULL)

#define hashmap__set(map, key, value, old_key, old_value) \
	hashmap__insert((map), (key), (value), HASHMAP_SET, (old_key), (old_value))

#define hashmap__update(map, key, value, old_key, old_value) \
	hashmap__insert((map), (key), (value), HASHMAP_UPDATE, (old_key), (old_value))

#define hashmap__append(map, key, value) \
	hashmap__insert((map), (key), (value), HASHMAP_APPEND, NULL, NULL)

Annotation

Implementation Notes