linux kernel code crypto zlib.c 2

static int zlib_compress_init(struct crypto_pcomp *tfm)
{
int ret;
struct zlib_ctx *dctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
struct z_stream_s *stream = &dctx->comp_stream;

ret = zlib_deflateReset(stream);
if (ret != Z_OK)
return -EINVAL;

return 0;
}

static int zlib_compress_update(struct crypto_pcomp *tfm,
struct comp_request *req)
{
int ret;
struct zlib_ctx *dctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
struct z_stream_s *stream = &dctx->comp_stream;

pr_debug(“avail_in %u, avail_out %u\n”, req->avail_in, req->avail_out);
stream->next_in = req->next_in;
stream->avail_in = req->avail_in;
stream->next_out = req->next_out;
stream->avail_out = req->avail_out;

ret = zlib_deflate(stream, Z_NO_FLUSH);
switch (ret) {
case Z_OK:
break;

case Z_BUF_ERROR:
pr_debug(“zlib_deflate could not make progress\n”);
return -EAGAIN;

default:
pr_debug(“zlib_deflate failed %d\n”, ret);
return -EINVAL;
}

ret = req->avail_out – stream->avail_out;
pr_debug(“avail_in %u, avail_out %u (consumed %u, produced %u)\n”,
stream->avail_in, stream->avail_out,
req->avail_in – stream->avail_in, ret);
req->next_in = stream->next_in;
req->avail_in = stream->avail_in;
req->next_out = stream->next_out;
req->avail_out = stream->avail_out;
return ret;
}

static int zlib_compress_final(struct crypto_pcomp *tfm,
struct comp_request *req)
{
int ret;
struct zlib_ctx *dctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
struct z_stream_s *stream = &dctx->comp_stream;

pr_debug(“avail_in %u, avail_out %u\n”, req->avail_in, req->avail_out);
stream->next_in = req->next_in;
stream->avail_in = req->avail_in;
stream->next_out = req->next_out;
stream->avail_out = req->avail_out;

ret = zlib_deflate(stream, Z_FINISH);
if (ret != Z_STREAM_END) {
pr_debug(“zlib_deflate failed %d\n”, ret);
return -EINVAL;
}

ret = req->avail_out – stream->avail_out;
pr_debug(“avail_in %u, avail_out %u (consumed %u, produced %u)\n”,
stream->avail_in, stream->avail_out,
req->avail_in – stream->avail_in, ret);
req->next_in = stream->next_in;
req->avail_in = stream->avail_in;
req->next_out = stream->next_out;
req->avail_out = stream->avail_out;
return ret;
}

static int zlib_decompress_setup(struct crypto_pcomp *tfm, void *params,
unsigned int len)
{
struct zlib_ctx *ctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
struct z_stream_s *stream = &ctx->decomp_stream;
struct nlattr *tb[ZLIB_DECOMP_MAX + 1];
int ret = 0;

ret = nla_parse(tb, ZLIB_DECOMP_MAX, params, len, NULL);
if (ret)
return ret;

zlib_decomp_exit(ctx);

ctx->decomp_windowBits = tb[ZLIB_DECOMP_WINDOWBITS]
? nla_get_u32(tb[ZLIB_DECOMP_WINDOWBITS])
: DEF_WBITS;

stream->workspace = kzalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
if (!stream->workspace)
return -ENOMEM;

ret = zlib_inflateInit2(stream, ctx->decomp_windowBits);
if (ret != Z_OK) {
kfree(stream->workspace);
stream->workspace = NULL;
return -EINVAL;
}

return 0;
}

static int zlib_decompress_init(struct crypto_pcomp *tfm)
{
int ret;
struct zlib_ctx *dctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
struct z_stream_s *stream = &dctx->decomp_stream;

ret = zlib_inflateReset(stream);
if (ret != Z_OK)
return -EINVAL;

return 0;
}

static int zlib_decompress_update(struct crypto_pcomp *tfm,
struct comp_request *req)
{
int ret;
struct zlib_ctx *dctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
struct z_stream_s *stream = &dctx->decomp_stream;

pr_debug(“avail_in %u, avail_out %u\n”, req->avail_in, req->avail_out);
stream->next_in = req->next_in;
stream->avail_in = req->avail_in;
stream->next_out = req->next_out;
stream->avail_out = req->avail_out;

ret = zlib_inflate(stream, Z_SYNC_FLUSH);
switch (ret) {
case Z_OK:
case Z_STREAM_END:
break;

case Z_BUF_ERROR:
pr_debug(“zlib_inflate could not make progress\n”);
return -EAGAIN;

default:
pr_debug(“zlib_inflate failed %d\n”, ret);
return -EINVAL;
}

ret = req->avail_out – stream->avail_out;
pr_debug(“avail_in %u, avail_out %u (consumed %u, produced %u)\n”,
stream->avail_in, stream->avail_out,
req->avail_in – stream->avail_in, ret);
req->next_in = stream->next_in;
req->avail_in = stream->avail_in;
req->next_out = stream->next_out;
req->avail_out = stream->avail_out;
return ret;
}

static int zlib_decompress_final(struct crypto_pcomp *tfm,
struct comp_request *req)
{
int ret;
struct zlib_ctx *dctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
struct z_stream_s *stream = &dctx->decomp_stream;

pr_debug(“avail_in %u, avail_out %u\n”, req->avail_in, req->avail_out);
stream->next_in = req->next_in;
stream->avail_in = req->avail_in;
stream->next_out = req->next_out;
stream->avail_out = req->avail_out;

if (dctx->decomp_windowBits < 0) {
ret = zlib_inflate(stream, Z_SYNC_FLUSH);
/*
* Work around a bug in zlib, which sometimes wants to taste an
* extra byte when being used in the (undocumented) raw deflate
* mode. (From USAGI).
*/
if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
const void *saved_next_in = stream->next_in;
u8 zerostuff = 0;

stream->next_in = &zerostuff;
stream->avail_in = 1;
ret = zlib_inflate(stream, Z_FINISH);
stream->next_in = saved_next_in;
stream->avail_in = 0;
}
} else
ret = zlib_inflate(stream, Z_FINISH);
if (ret != Z_STREAM_END) {
pr_debug(“zlib_inflate failed %d\n”, ret);
return -EINVAL;
}

ret = req->avail_out – stream->avail_out;
pr_debug(“avail_in %u, avail_out %u (consumed %u, produced %u)\n”,
stream->avail_in, stream->avail_out,
req->avail_in – stream->avail_in, ret);
req->next_in = stream->next_in;
req->avail_in = stream->avail_in;
req->next_out = stream->next_out;
req->avail_out = stream->avail_out;
return ret;
}

static struct pcomp_alg zlib_alg = {
.compress_setup        = zlib_compress_setup,
.compress_init        = zlib_compress_init,
.compress_update    = zlib_compress_update,
.compress_final        = zlib_compress_final,
.decompress_setup    = zlib_decompress_setup,
.decompress_init    = zlib_decompress_init,
.decompress_update    = zlib_decompress_update,
.decompress_final    = zlib_decompress_final,

.base            = {
.cra_name    = “zlib”,
.cra_flags    = CRYPTO_ALG_TYPE_PCOMPRESS,
.cra_ctxsize    = sizeof(struct zlib_ctx),
.cra_module    = THIS_MODULE,
.cra_init    = zlib_init,
.cra_exit    = zlib_exit,
}
};

static int __init zlib_mod_init(void)
{
return crypto_register_pcomp(&zlib_alg);
}

static void __exit zlib_mod_fini(void)
{
crypto_unregister_pcomp(&zlib_alg);
}

module_init(zlib_mod_init);
module_exit(zlib_mod_fini);

MODULE_LICENSE(“GPL”);
MODULE_DESCRIPTION(“Zlib Compression Algorithm”);
MODULE_AUTHOR(“Sony Corporation”);