fixup! feat!: implement libcmt

sys-utils/libcmt/README.md

@@ -1,16 +1,15 @@
-High level
+This is a C library to facilitate IO interactions of applications running in the cartesi-machine.
 
-- @ref libcmt\_rollup
+The high level @ref libcmt\_rollup API provides functions for common operations, such as generating vouchers, notices, retrieving the next input, etc.
+Check the [cartesi documentation](https://docs.cartesi.io/) for an introduction and explanation of the rollup interaction model.
 
-Utility
+In addition to the above mentioned module, we provide @ref libcmt\_io\_driver, a thin abstraction of the linux kernel driver.
 
-- @ref libcmt\_abi
-- @ref libcmt\_buf
-- @ref libcmt\_merkle
-- @ref libcmt\_keccak
+And finally there are the utility modules used by the high level API.
+- @ref libcmt\_abi is a Ethereum Virtual Machine Application Binary Interface (EVM-ABI) encoder / decoder.
+- @ref libcmt\_buf is a bounds checking buffer.
+- @ref libcmt\_merkle is a sparse merkle tree implementation on top of keccak.
+- @ref libcmt\_keccak is the hashing function used extensively by Ethereum.
 
-Low level
-
-- @ref libcmt\_io\_driver
-
-Download the static library from [cartesi tools](https://github.com/cartesi/machine-emulator-tools/).
+The header files and a compiled RISC-V version of this library can be found [here](https://github.com/cartesi/machine-emulator-tools/).
+We also provide `.pc` (pkg-config) files to facilitate linking.

sys-utils/libcmt/src/abi.c

@@ -182,10 +182,10 @@ uint32_t cmt_abi_peek_funsel(cmt_buf_t *me)
 int cmt_abi_check_funsel(cmt_buf_t *me, uint32_t expected)
 {
 	if (cmt_buf_length(me) < 4)
-		return ENOBUFS;
+		return -ENOBUFS;
 
 	if (cmt_abi_peek_funsel(me) != expected)
-		return EBADMSG;
+		return -EBADMSG;
 
 	me->begin += 4;
 	return 0;

sys-utils/libcmt/src/rollup.c

@@ -261,8 +261,10 @@ int cmt_rollup_finish(cmt_rollup_t *me, cmt_rollup_finish_t *finish)
 	}
 
 	cmt_merkle_get_root_hash(me->merkle, me->tx->begin);
-	return finish->next_request_type = accepted
-		(me->io, &finish->next_request_payload_length);
+	finish->next_request_type =
+		accepted(me->io, &finish->next_request_payload_length);
+	cmt_merkle_init(me->merkle);
+	return finish->next_request_type;
 }
 
 int