rust-bitcoinkernel

rust-bitcoinkernel is a wrapper around libbitcoinkernel, an experimental C++ library exposing Bitcoin Core's validation engine. It supports both validation of blocks and transaction outputs as well as reading block data.

Building

The library statically compiles the Bitcoin Core libbitcoinkernel library as part of its build system.

Bitcoin Core is vendored as a git subtree in this project. The subtree can be updated, or made to point at a different commit or branch in Bitcoin Core's history with:

git subtree pull --prefix libbitcoinkernel-sys/bitcoin https://github.com/bitcoin/bitcoin master --squash

To build this library, the usual Bitcoin Core build requirements, such as cmake and a working C and C++ compiler are required. An installation of boost is required as well. Consult the Bitcoin Core documentation for the required dependencies. Once setup, run:

cargo b

Examples

Examples for the usage of the library can be found in the examples/ directory and the tests. For now, the example binary implements a bare-bones silent payments scanner.

Fuzzing

Fuzzing is done with cargo fuzz.

There are currently three supported fuzzing targets: block_roundtrip, chainman_process_block and script_verify. The chainman target touches the filesystem in /tmp. If /tmp is not already a tmpfs, the user should create a tmpfs in /tmp/rust_kernel_fuzz.

To get fuzzing run (in this case the verify target):

cargo fuzz run script_verify

Sanitizers can be turned on with e.g.

RUSTFLAGS="-Zsanitizer=address" cargo fuzz run block_roundtrip

To get the sanitizer flags working in the libbitcoinkernel Bitcoin Core library, the easiest way for now is to edit the libbitcoinkernel-sys/build.rs flags.

Coverage

Once fuzzed, a coverage report can be generated with (picking the verify target as an example):

RUSTFLAGS="-C instrument-coverage" cargo fuzz coverage script_verify
llvm-cov show \
  -format=html \
  -instr-profile=fuzz/coverage/script_verify/coverage.profdata \
  target/x86_64-unknown-linux-gnu/coverage/x86_64-unknown-linux-gnu/release/script_verify \
  -show-line-counts-or-regions \
  -Xdemangler=rustfilt \
  -output-dir=coverage_report \
  -ignore-filename-regex="/rustc"

You may have to install the following tooling:

rustup component add llvm-tools-preview
cargo install rustfilt