net: rpc: openthread: dynamic allocation for CLI commands

include/nrf_rpc/nrf_rpc_serialize.h

@@ -229,6 +229,15 @@ int64_t nrf_rpc_decode_int64(struct nrf_rpc_cbor_ctx *ctx);
  */
 char *nrf_rpc_decode_str(struct nrf_rpc_cbor_ctx *ctx, char *buffer, size_t buffer_size);
 
+/** @brief Decode a string pointer and length. Moves CBOR pointer past string on success.
+ *
+ * @param[in,out] ctx CBOR decoding context.
+ * @param[out]  size String length.
+ *
+ * @retval Pointer to a string within CBOR stream or NULL on error.
+ */
+const void *nrf_rpc_decode_str_ptr_and_len(struct nrf_rpc_cbor_ctx *ctx, size_t *len);
+
 /** Decode a string value into a scratchpad.
  *
  * @param[in] scratchpad Pointer to the scratchpad.

subsys/net/openthread/rpc/server/ot_rpc_cli.c

@@ -68,32 +68,43 @@ NRF_RPC_CBOR_CMD_DECODER(ot_group, ot_rpc_cmd_cli_init, OT_RPC_CMD_CLI_INIT, ot_
 static void ot_rpc_cmd_cli_input_line(const struct nrf_rpc_group *group,
 				      struct nrf_rpc_cbor_ctx *ctx, void *handler_data)
 {
-	char input_line_buffer[256];
 	struct nrf_rpc_cbor_ctx rsp_ctx;
-	char *result;
+	char *buffer;
+	const void *ptr;
+	size_t len;
 
 	/* Parse the input */
-	result = nrf_rpc_decode_str(ctx, input_line_buffer, sizeof(input_line_buffer));
+	ptr = nrf_rpc_decode_str_ptr_and_len(ctx, &len);
+
+	if (ptr) {
+		buffer = malloc(len + 1);
+		if (buffer) {
+			memcpy(buffer, ptr, len);
+			buffer[len] = '\0';
+		}
+	}
 
 	if (!nrf_rpc_decoding_done_and_check(group, ctx)) {
 		ot_rpc_report_cmd_decoding_error(OT_RPC_CMD_CLI_INPUT_LINE);
 		return;
 	}
 
-	if (result == NULL) {
+	if (!ptr || !buffer) {
 		return;
 	}
 
 	/* Execute OT CLI command */
 	openthread_api_mutex_lock(openthread_get_default_context());
-	otCliInputLine(input_line_buffer);
+	otCliInputLine(buffer);
 	openthread_api_mutex_unlock(openthread_get_default_context());
 
 	/* Encode and send the response */
 
 	NRF_RPC_CBOR_ALLOC(group, rsp_ctx, 0);
 
 	nrf_rpc_cbor_rsp_no_err(group, &rsp_ctx);
+
+	free(buffer);
 }
 
 NRF_RPC_CBOR_CMD_DECODER(ot_group, ot_rpc_cmd_cli_input_line, OT_RPC_CMD_CLI_INPUT_LINE,

subsys/nrf_rpc/nrf_rpc_serialize.c

@@ -318,6 +318,32 @@ char *nrf_rpc_decode_str(struct nrf_rpc_cbor_ctx *ctx, char *buffer, size_t buff
 	return buffer;
 }
 
+const void *nrf_rpc_decode_str_ptr_and_len(struct nrf_rpc_cbor_ctx *ctx, size_t *len)
+{
+	struct zcbor_string zst = {0};
+
+	if (is_decoder_invalid(ctx)) {
+		return NULL;
+	}
+
+	if (zcbor_nil_expect(ctx->zs, NULL)) {
+		return NULL;
+	}
+
+	if (ctx->zs->constant_state->error != ZCBOR_ERR_WRONG_TYPE) {
+		return NULL;
+	}
+
+	zcbor_pop_error(ctx->zs);
+
+	if (!zcbor_tstr_decode(ctx->zs, &zst)) {
+		return NULL;
+	}
+
+	*len = zst.len;
+	return zst.value;
+}
+
 char *nrf_rpc_decode_str_into_scratchpad(struct nrf_rpc_scratchpad *scratchpad, size_t *len)
 {
 	struct nrf_rpc_cbor_ctx *ctx = scratchpad->ctx;