Higher-level API about libprotobuf-mutator HOT 5 CLOSED

I agree we should do something like this, but not sure how.
Your 3 variants all look sane, the first one is better, if we can implement it.
Before coming up with a 'final' interface I'd like to have 2-3 examples in this repo using the existing (verbose) interface.

One question: what headers are we going to require?
Obviously, we will need #include "myproto.pb.h", but what else?
I don't want to require any headers from libFuzzer.
And if possible not even from libprotobuf-mutator

use data+size as input
did you mean use proto as input?

from libprotobuf-mutator.

I don't know if not including mutator header is feasible. We discussed this at length and we didn't find a way to discover function with unknown signature.

But this brings a related question to my mind: maybe we want mutator library to be header-only?

PS fixed code samples comments

from libprotobuf-mutator.

maybe we want mutator library to be header-only?

That's possible and might be a part of solution.
But then again, what if we want to use some other proto mutation tool?

I don't know if not including mutator header is feasible.

Well, at the very least we can use the -i compiler flag to include something under the hood for cases were we control the build system.

Anyway, let's not rush here. With more proto fuzz targets a better understanding may come.

from libprotobuf-mutator.

We should not use header only, as it will force us to compile and instrument mutator together with fuzz target.

If we want to avoid headers at all, we can go with:

extern "C" google::protobuf::Message* LLVMFuzzerGetDefaultProto() {
  return MyProto::default_instance();
}
extern "C" int LLVMFuzzerTestProto(google::protobuf::Message& message) {
  const MyProto& my_message = static_cast<const MyProto&>(message);
  ....
  return 0;
}

So user will have to cast.

If we allow some small header, I'd go with

void SomeTestCode(const MyProto& message) {
}
protobuf_mutator::libfuzzer::TextFuzzer<MyProto> fuzzer(&SomeTestCode); // or just lambda

Which can be reduced to macro, like in the first comment:

LLVM_FUZZER_PROTO(const MyProto& proto) {
}

from libprotobuf-mutator.

Fixed with #63

from libprotobuf-mutator.