/* Copyright (C) 2012 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by the GPL v2 license that can
 * be found in the LICENSE file.
 *
 * These files provide equivalent implementations for kernel calls for
 * compatibility with files under SRC/include.
 */

#include <linux/bug.h>
#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <linux/init.h>
#include <crypto/hash.h>

static size_t num_hashes = 0;
static struct shash_alg **hashes = NULL;

int crypto_register_shash(struct shash_alg *alg)
{
	hashes = realloc(hashes, sizeof(*hashes) * (num_hashes + 1));
	hashes[num_hashes++] = alg;
	return 0;
}

struct hash_tfm *crypto_alloc_hash(const char *alg_name, int a, int b)
{
	size_t i;
	struct hash_tfm *tfm;

	if (!hashes) {
		/* need to initialize our world */
		CALL_MODULE_INIT(md5_mod_init);
		CALL_MODULE_INIT(sha1_generic_mod_init);
		CALL_MODULE_INIT(sha256_generic_mod_init);
	}
	BUG_ON(!hashes);

	for (i = 0; i < num_hashes; ++i)
		if (!strcasecmp(alg_name, hashes[i]->base.cra_name))
			break;
	BUG_ON(i == num_hashes);

	tfm = calloc(sizeof(*tfm) + hashes[i]->statesize, 1);
	BUG_ON(!tfm);
	tfm->alg = hashes[i];

	return tfm;
}

void crypto_free_hash(struct hash_tfm *tfm)
{
	free(tfm);
}

unsigned int crypto_hash_digestsize(struct hash_tfm *tfm)
{
	BUG_ON(!tfm);
	return tfm->alg->digestsize;
}

int crypto_hash_init(struct hash_desc *h)
{
	const struct shash_alg *alg = h->tfm->alg;
	struct shash_desc *desc = &h->tfm->desc;

	return alg->init(desc);
}

int crypto_hash_digest(struct hash_desc *h, struct scatterlist *sg,
		       unsigned int sz, u8 *dst)
{
	const struct shash_alg *alg = h->tfm->alg;
	struct shash_desc *desc = &h->tfm->desc;
	u8 *buffer = (u8 *)(sg->buffer) + sg->offset;

	return alg->digest(desc, buffer, sz, dst);
}

int crypto_hash_update(struct hash_desc *h, struct scatterlist *sg,
		       unsigned int size)
{
	const struct shash_alg *alg = h->tfm->alg;
	struct shash_desc *desc = &h->tfm->desc;
	u8 *buffer = (u8 *)(sg->buffer) + sg->offset;

	return alg->update(desc, buffer, size);
}

int crypto_hash_final(struct hash_desc *h, u8 *dst)
{
	const struct shash_alg *alg = h->tfm->alg;
	struct shash_desc *desc = &h->tfm->desc;

	return alg->final(desc, dst);
}