Add support for post_process in Rust custom mutator + associated example with lain (#2241)

1 files changed, 9 insertions, 1 deletions

diff --git a/custom_mutators/rust/README.md b/custom_mutators/rust/README.md
index e2cc38b4..a23b19df 100644
--- a/custom_mutators/rust/README.md
+++ b/custom_mutators/rust/README.md
@@ -5,7 +5,15 @@ Bindings to create custom mutators in Rust.
 These bindings are documented with rustdoc. To view the documentation run
 ```cargo doc -p custom_mutator --open```.
 
-A minimal example can be found in `example`. Build it using `cargo build --example example_mutator`. 
+A minimal example can be found in `example`. Build it using `cargo build --example example_mutator`.
 
 An example using [lain](https://github.com/microsoft/lain) for structured fuzzing can be found in `example_lain`.
 Since lain requires a nightly rust toolchain, you need to set one up before you can play with it.
+
+An example for the use of the post_process function, using [lain](https://github.com/microsoft/lain) with [serde](https://github.com/serde-rs/serde) and [bincode](https://github.com/bincode-org/bincode) can be found in `example_lain_post_process`.
+In order for it to work you need to:
+
+- disable input trimming with `AFL_DISABLE_TRIM=1`
+- provide an initial instance serialized with `bincode` or use the `AFL_NO_STARTUP_CALIBRATION=1` environment variable.
+
+Note that `bincode` can also be used to serialize/deserialize the lain-generated structure and mutate it rather than generating a new one at each iteration, but it requires some structure serialized with `bincode` as input seed.