text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * Cryptographic API.
   */
  
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/crypto.h>
  #include <linux/vmalloc.h>
  #include <linux/mm.h>
  #include <linux/lzo.h>
  #include <crypto/internal/scompress.h>
  
  struct lzorle_ctx {
  	void *lzorle_comp_mem;
  };
  
  static void *lzorle_alloc_ctx(struct crypto_scomp *tfm)
  {
  	void *ctx;
  
  	ctx = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
  	if (!ctx)
  		return ERR_PTR(-ENOMEM);
  
  	return ctx;
  }
  
  static int lzorle_init(struct crypto_tfm *tfm)
  {
  	struct lzorle_ctx *ctx = crypto_tfm_ctx(tfm);
  
  	ctx->lzorle_comp_mem = lzorle_alloc_ctx(NULL);
  	if (IS_ERR(ctx->lzorle_comp_mem))
  		return -ENOMEM;
  
  	return 0;
  }
  
  static void lzorle_free_ctx(struct crypto_scomp *tfm, void *ctx)
  {
  	kvfree(ctx);
  }
  
  static void lzorle_exit(struct crypto_tfm *tfm)
  {
  	struct lzorle_ctx *ctx = crypto_tfm_ctx(tfm);
  
  	lzorle_free_ctx(NULL, ctx->lzorle_comp_mem);
  }
  
  static int __lzorle_compress(const u8 *src, unsigned int slen,
  			  u8 *dst, unsigned int *dlen, void *ctx)
  {
  	size_t tmp_len = *dlen; /* size_t(ulong) <-> uint on 64 bit */
  	int err;
  
  	err = lzorle1x_1_compress(src, slen, dst, &tmp_len, ctx);
  
  	if (err != LZO_E_OK)
  		return -EINVAL;
  
  	*dlen = tmp_len;
  	return 0;
  }
  
  static int lzorle_compress(struct crypto_tfm *tfm, const u8 *src,
  			unsigned int slen, u8 *dst, unsigned int *dlen)
  {
  	struct lzorle_ctx *ctx = crypto_tfm_ctx(tfm);
  
  	return __lzorle_compress(src, slen, dst, dlen, ctx->lzorle_comp_mem);
  }
  
  static int lzorle_scompress(struct crypto_scomp *tfm, const u8 *src,
  			 unsigned int slen, u8 *dst, unsigned int *dlen,
  			 void *ctx)
  {
  	return __lzorle_compress(src, slen, dst, dlen, ctx);
  }
  
  static int __lzorle_decompress(const u8 *src, unsigned int slen,
  			    u8 *dst, unsigned int *dlen)
  {
  	int err;
  	size_t tmp_len = *dlen; /* size_t(ulong) <-> uint on 64 bit */
  
  	err = lzo1x_decompress_safe(src, slen, dst, &tmp_len);
  
  	if (err != LZO_E_OK)
  		return -EINVAL;
  
  	*dlen = tmp_len;
  	return 0;
  }
  
  static int lzorle_decompress(struct crypto_tfm *tfm, const u8 *src,
  			  unsigned int slen, u8 *dst, unsigned int *dlen)
  {
  	return __lzorle_decompress(src, slen, dst, dlen);
  }
  
  static int lzorle_sdecompress(struct crypto_scomp *tfm, const u8 *src,
  			   unsigned int slen, u8 *dst, unsigned int *dlen,
  			   void *ctx)
  {
  	return __lzorle_decompress(src, slen, dst, dlen);
  }
  
  static struct crypto_alg alg = {
  	.cra_name		= "lzo-rle",
  	.cra_driver_name	= "lzo-rle-generic",
  	.cra_flags		= CRYPTO_ALG_TYPE_COMPRESS,
  	.cra_ctxsize		= sizeof(struct lzorle_ctx),
  	.cra_module		= THIS_MODULE,
  	.cra_init		= lzorle_init,
  	.cra_exit		= lzorle_exit,
  	.cra_u			= { .compress = {
  	.coa_compress		= lzorle_compress,
  	.coa_decompress		= lzorle_decompress } }
  };
  
  static struct scomp_alg scomp = {
  	.alloc_ctx		= lzorle_alloc_ctx,
  	.free_ctx		= lzorle_free_ctx,
  	.compress		= lzorle_scompress,
  	.decompress		= lzorle_sdecompress,
  	.base			= {
  		.cra_name	= "lzo-rle",
  		.cra_driver_name = "lzo-rle-scomp",
  		.cra_module	 = THIS_MODULE,
  	}
  };
  
  static int __init lzorle_mod_init(void)
  {
  	int ret;
  
  	ret = crypto_register_alg(&alg);
  	if (ret)
  		return ret;
  
  	ret = crypto_register_scomp(&scomp);
  	if (ret) {
  		crypto_unregister_alg(&alg);
  		return ret;
  	}
  
  	return ret;
  }
  
  static void __exit lzorle_mod_fini(void)
  {
  	crypto_unregister_alg(&alg);
  	crypto_unregister_scomp(&scomp);
  }
  
  subsys_initcall(lzorle_mod_init);
  module_exit(lzorle_mod_fini);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("LZO-RLE Compression Algorithm");
  MODULE_ALIAS_CRYPTO("lzo-rle");
  