Ethereum VM trace visualizer

geth outputs a VM trace for an Ethereum transaction, by debug.traceTransaction() function. This repository contains a small ruby program that annotates the traces with the original steps that produced the operands.

The enricher tries to answer questions like

• how does this contract calculate the value it sends?
• how does this contract determine the address it calls?

on concrete transaction logs.

Currently the enricher keeps track of the origins of values on the stack.

Usage

After checking out this repository:

ruby src/enricher.rb example/example_1.json | less

is a way to use it.

Example

Before the transformation

{
	"depth":1,
	"error":null,
	"gas":977788,
	"gasCost":20,
	"memory":[
		"0000000000000000000000000000000000000000000000000000000000000000",
		"0000000000000000000000000000000000000000000000000000000000000000",
		"0000000000000000000000000000000000000000000000000000000000000060"
	],
	"op":"EXP",
	"pc":9,
	"stack":[
		"00000000000000000000000000000000000000000000000000000000000000e0",
		"0000000000000000000000000000000000000000000000000000000000000002"
	],
	"storage":{}
},

After the transformation

{
	"depth":1,
	"error":null,
	"gas":977788,
	"gasCost":20,
	"memory":[
		"0000000000000000000000000000000000000000000000000000000000000000",
		"0000000000000000000000000000000000000000000000000000000000000000",
		"0000000000000000000000000000000000000000000000000000000000000060"
	],
	"op":"EXP",
	"pc":9,
	"stack":[
		"00000000000000000000000000000000000000000000000000000000000000e0",
		"0000000000000000000000000000000000000000000000000000000000000002"
	],
	"storage":{
	},
+	"step":5,
+	"arg_origins":[
+		{
+			"depth":1,
+			"step":3
+		},
+		{
+			"depth":1,
+			"step":4
+		}
+	]
},

Graphviz output

As a preparation, you need the graphviz tools:

sudo apt install graphviz

Then,

ruby src/enricher.rb -g example/example_1.json > graph.dot && \
dot -Tpdf graph.dot -o graph.pdf

would produce a data-flow diagram in graph.pdf.

How to obtain vm traces

The input JSON can be obtained from geth RPC. See example/get_example_1.sh for how.