Clean up fuzz crate: use panic=abort, add stdin_fuzz support, remove dylib

This commit makes three related changes to the fuzz infrastructure:

1. Set panic=abort on both dev and release profiles, and remove the
   dylib crate type (keeping rlib and staticlib). The dylib crate type
   was added in e28fd78 (2019) for a C-callable harness that was
   never implemented. Removing dylib is what enables panic=abort,
   since Rust forces panic=unwind on dylib crates. staticlib is
   retained as it is compatible with panic=abort.

2. Add stdin_fuzz support: a new Stdout logger, updated target template
   so that stdin_fuzz calls _test() with Stdout logging, and updated
   README with usage instructions. This allows reproducing crashes via
   piped input, useful for git bisect and AI-assisted debugging.

3. Update all fuzzer frontends (AFL, honggfuzz, libfuzzer, stdin_fuzz)
   to call the _test() functions directly instead of going through the
   _run() C wrappers.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: joostjager

fuzz/Cargo.toml

@@ -39,19 +39,21 @@ cc = "1.0"
 members = ["."]
 
 [profile.release]
+panic = "abort"
 lto = true
 codegen-units = 1
 debug-assertions = true
 overflow-checks = true
 
 # When testing a large fuzz corpus, -O1 offers a nice speedup
 [profile.dev]
+panic = "abort"
 opt-level = 1
 
 [lib]
 name = "lightning_fuzz"
 path = "src/lib.rs"
-crate-type = ["rlib", "dylib", "staticlib"]
+crate-type = ["rlib", "staticlib"]
 
 [lints.rust.unexpected_cfgs]
 level = "forbid"

fuzz/README.md

@@ -148,6 +148,16 @@ mv hfuzz_workspace/fuzz_target/SIGABRT.PC.7ffff7e21ce1.STACK.[…].fuzz ./test_c
 
 This will reproduce the failing fuzz input and yield a usable stack trace.
 
+Alternatively, you can use the `stdin_fuzz` feature to pipe the crash input directly without
+creating test case files on disk:
+
+```shell
+echo -ne '\x2d\x31\x36\x38\x37\x34\x09\x01...' | RUSTFLAGS="--cfg=fuzzing --cfg=secp256k1_fuzz --cfg=hashes_fuzz" cargo run --features stdin_fuzz --bin full_stack_target
+```
+
+Panics will abort the process directly (the crate uses `panic = "abort"`), resulting in a
+non-zero exit code. Piping via stdin is useful for reproducing crashes during `git bisect` or
+when working with AI agents that can construct and pipe byte sequences directly.
 
 ## How do I add a new fuzz test?
 

fuzz/src/bin/base32_target.rs

@@ -24,13 +24,14 @@ compile_error!("Fuzz targets need cfg=secp256k1_fuzz");
 
 extern crate lightning_fuzz;
 use lightning_fuzz::base32::*;
+use lightning_fuzz::utils::test_logger;
 
 #[cfg(feature = "afl")]
 #[macro_use] extern crate afl;
 #[cfg(feature = "afl")]
 fn main() {
 	fuzz!(|data| {
-		base32_run(data.as_ptr(), data.len());
+		base32_test(&data, test_logger::DevNull {});
 	});
 }
 
@@ -40,7 +41,7 @@ fn main() {
 fn main() {
 	loop {
 		fuzz!(|data| {
-			base32_run(data.as_ptr(), data.len());
+			base32_test(&data, test_logger::DevNull {});
 		});
 	}
 }
@@ -49,7 +50,7 @@ fn main() {
 #[macro_use] extern crate libfuzzer_sys;
 #[cfg(feature = "libfuzzer_fuzz")]
 fuzz_target!(|data: &[u8]| {
-	base32_run(data.as_ptr(), data.len());
+	base32_test(data, test_logger::DevNull {});
 });
 
 #[cfg(feature = "stdin_fuzz")]
@@ -58,7 +59,7 @@ fn main() {
 
 	let mut data = Vec::with_capacity(8192);
 	std::io::stdin().read_to_end(&mut data).unwrap();
-	base32_run(data.as_ptr(), data.len());
+	base32_test(&data, lightning_fuzz::utils::test_logger::Stdout {});
 }
 
 #[test]
@@ -70,7 +71,7 @@ fn run_test_cases() {
 	use std::sync::{atomic, Arc};
 	{
 		let data: Vec<u8> = vec![0];
-		base32_run(data.as_ptr(), data.len());
+		base32_test(&data, test_logger::DevNull {});
 	}
 	let mut threads = Vec::new();
 	let threads_running = Arc::new(atomic::AtomicUsize::new(0));

fuzz/src/bin/bech32_parse_target.rs

@@ -24,13 +24,14 @@ compile_error!("Fuzz targets need cfg=secp256k1_fuzz");
 
 extern crate lightning_fuzz;
 use lightning_fuzz::bech32_parse::*;
+use lightning_fuzz::utils::test_logger;
 
 #[cfg(feature = "afl")]
 #[macro_use] extern crate afl;
 #[cfg(feature = "afl")]
 fn main() {
 	fuzz!(|data| {
-		bech32_parse_run(data.as_ptr(), data.len());
+		bech32_parse_test(&data, test_logger::DevNull {});
 	});
 }
 
@@ -40,7 +41,7 @@ fn main() {
 fn main() {
 	loop {
 		fuzz!(|data| {
-			bech32_parse_run(data.as_ptr(), data.len());
+			bech32_parse_test(&data, test_logger::DevNull {});
 		});
 	}
 }
@@ -49,7 +50,7 @@ fn main() {
 #[macro_use] extern crate libfuzzer_sys;
 #[cfg(feature = "libfuzzer_fuzz")]
 fuzz_target!(|data: &[u8]| {
-	bech32_parse_run(data.as_ptr(), data.len());
+	bech32_parse_test(data, test_logger::DevNull {});
 });
 
 #[cfg(feature = "stdin_fuzz")]
@@ -58,7 +59,7 @@ fn main() {
 
 	let mut data = Vec::with_capacity(8192);
 	std::io::stdin().read_to_end(&mut data).unwrap();
-	bech32_parse_run(data.as_ptr(), data.len());
+	bech32_parse_test(&data, lightning_fuzz::utils::test_logger::Stdout {});
 }
 
 #[test]
@@ -70,7 +71,7 @@ fn run_test_cases() {
 	use std::sync::{atomic, Arc};
 	{
 		let data: Vec<u8> = vec![0];
-		bech32_parse_run(data.as_ptr(), data.len());
+		bech32_parse_test(&data, test_logger::DevNull {});
 	}
 	let mut threads = Vec::new();
 	let threads_running = Arc::new(atomic::AtomicUsize::new(0));

fuzz/src/bin/bolt11_deser_target.rs

@@ -24,13 +24,14 @@ compile_error!("Fuzz targets need cfg=secp256k1_fuzz");
 
 extern crate lightning_fuzz;
 use lightning_fuzz::bolt11_deser::*;
+use lightning_fuzz::utils::test_logger;
 
 #[cfg(feature = "afl")]
 #[macro_use] extern crate afl;
 #[cfg(feature = "afl")]
 fn main() {
 	fuzz!(|data| {
-		bolt11_deser_run(data.as_ptr(), data.len());
+		bolt11_deser_test(&data, test_logger::DevNull {});
 	});
 }
 
@@ -40,7 +41,7 @@ fn main() {
 fn main() {
 	loop {
 		fuzz!(|data| {
-			bolt11_deser_run(data.as_ptr(), data.len());
+			bolt11_deser_test(&data, test_logger::DevNull {});
 		});
 	}
 }
@@ -49,7 +50,7 @@ fn main() {
 #[macro_use] extern crate libfuzzer_sys;
 #[cfg(feature = "libfuzzer_fuzz")]
 fuzz_target!(|data: &[u8]| {
-	bolt11_deser_run(data.as_ptr(), data.len());
+	bolt11_deser_test(data, test_logger::DevNull {});
 });
 
 #[cfg(feature = "stdin_fuzz")]
@@ -58,7 +59,7 @@ fn main() {
 
 	let mut data = Vec::with_capacity(8192);
 	std::io::stdin().read_to_end(&mut data).unwrap();
-	bolt11_deser_run(data.as_ptr(), data.len());
+	bolt11_deser_test(&data, lightning_fuzz::utils::test_logger::Stdout {});
 }
 
 #[test]
@@ -70,7 +71,7 @@ fn run_test_cases() {
 	use std::sync::{atomic, Arc};
 	{
 		let data: Vec<u8> = vec![0];
-		bolt11_deser_run(data.as_ptr(), data.len());
+		bolt11_deser_test(&data, test_logger::DevNull {});
 	}
 	let mut threads = Vec::new();
 	let threads_running = Arc::new(atomic::AtomicUsize::new(0));

fuzz/src/bin/chanmon_consistency_target.rs

@@ -24,13 +24,14 @@ compile_error!("Fuzz targets need cfg=secp256k1_fuzz");
 
 extern crate lightning_fuzz;
 use lightning_fuzz::chanmon_consistency::*;
+use lightning_fuzz::utils::test_logger;
 
 #[cfg(feature = "afl")]
 #[macro_use] extern crate afl;
 #[cfg(feature = "afl")]
 fn main() {
 	fuzz!(|data| {
-		chanmon_consistency_run(data.as_ptr(), data.len());
+		chanmon_consistency_test(&data, test_logger::DevNull {});
 	});
 }
 
@@ -40,7 +41,7 @@ fn main() {
 fn main() {
 	loop {
 		fuzz!(|data| {
-			chanmon_consistency_run(data.as_ptr(), data.len());
+			chanmon_consistency_test(&data, test_logger::DevNull {});
 		});
 	}
 }
@@ -49,7 +50,7 @@ fn main() {
 #[macro_use] extern crate libfuzzer_sys;
 #[cfg(feature = "libfuzzer_fuzz")]
 fuzz_target!(|data: &[u8]| {
-	chanmon_consistency_run(data.as_ptr(), data.len());
+	chanmon_consistency_test(data, test_logger::DevNull {});
 });
 
 #[cfg(feature = "stdin_fuzz")]
@@ -58,7 +59,7 @@ fn main() {
 
 	let mut data = Vec::with_capacity(8192);
 	std::io::stdin().read_to_end(&mut data).unwrap();
-	chanmon_consistency_run(data.as_ptr(), data.len());
+	chanmon_consistency_test(&data, lightning_fuzz::utils::test_logger::Stdout {});
 }
 
 #[test]
@@ -70,7 +71,7 @@ fn run_test_cases() {
 	use std::sync::{atomic, Arc};
 	{
 		let data: Vec<u8> = vec![0];
-		chanmon_consistency_run(data.as_ptr(), data.len());
+		chanmon_consistency_test(&data, test_logger::DevNull {});
 	}
 	let mut threads = Vec::new();
 	let threads_running = Arc::new(atomic::AtomicUsize::new(0));

fuzz/src/bin/chanmon_deser_target.rs

@@ -24,13 +24,14 @@ compile_error!("Fuzz targets need cfg=secp256k1_fuzz");
 
 extern crate lightning_fuzz;
 use lightning_fuzz::chanmon_deser::*;
+use lightning_fuzz::utils::test_logger;
 
 #[cfg(feature = "afl")]
 #[macro_use] extern crate afl;
 #[cfg(feature = "afl")]
 fn main() {
 	fuzz!(|data| {
-		chanmon_deser_run(data.as_ptr(), data.len());
+		chanmon_deser_test(&data, test_logger::DevNull {});
 	});
 }
 
@@ -40,7 +41,7 @@ fn main() {
 fn main() {
 	loop {
 		fuzz!(|data| {
-			chanmon_deser_run(data.as_ptr(), data.len());
+			chanmon_deser_test(&data, test_logger::DevNull {});
 		});
 	}
 }
@@ -49,7 +50,7 @@ fn main() {
 #[macro_use] extern crate libfuzzer_sys;
 #[cfg(feature = "libfuzzer_fuzz")]
 fuzz_target!(|data: &[u8]| {
-	chanmon_deser_run(data.as_ptr(), data.len());
+	chanmon_deser_test(data, test_logger::DevNull {});
 });
 
 #[cfg(feature = "stdin_fuzz")]
@@ -58,7 +59,7 @@ fn main() {
 
 	let mut data = Vec::with_capacity(8192);
 	std::io::stdin().read_to_end(&mut data).unwrap();
-	chanmon_deser_run(data.as_ptr(), data.len());
+	chanmon_deser_test(&data, lightning_fuzz::utils::test_logger::Stdout {});
 }
 
 #[test]
@@ -70,7 +71,7 @@ fn run_test_cases() {
 	use std::sync::{atomic, Arc};
 	{
 		let data: Vec<u8> = vec![0];
-		chanmon_deser_run(data.as_ptr(), data.len());
+		chanmon_deser_test(&data, test_logger::DevNull {});
 	}
 	let mut threads = Vec::new();
 	let threads_running = Arc::new(atomic::AtomicUsize::new(0));

fuzz/src/bin/feature_flags_target.rs

@@ -24,13 +24,14 @@ compile_error!("Fuzz targets need cfg=secp256k1_fuzz");
 
 extern crate lightning_fuzz;
 use lightning_fuzz::feature_flags::*;
+use lightning_fuzz::utils::test_logger;
 
 #[cfg(feature = "afl")]
 #[macro_use] extern crate afl;
 #[cfg(feature = "afl")]
 fn main() {
 	fuzz!(|data| {
-		feature_flags_run(data.as_ptr(), data.len());
+		feature_flags_test(&data, test_logger::DevNull {});
 	});
 }
 
@@ -40,7 +41,7 @@ fn main() {
 fn main() {
 	loop {
 		fuzz!(|data| {
-			feature_flags_run(data.as_ptr(), data.len());
+			feature_flags_test(&data, test_logger::DevNull {});
 		});
 	}
 }
@@ -49,7 +50,7 @@ fn main() {
 #[macro_use] extern crate libfuzzer_sys;
 #[cfg(feature = "libfuzzer_fuzz")]
 fuzz_target!(|data: &[u8]| {
-	feature_flags_run(data.as_ptr(), data.len());
+	feature_flags_test(data, test_logger::DevNull {});
 });
 
 #[cfg(feature = "stdin_fuzz")]
@@ -58,7 +59,7 @@ fn main() {
 
 	let mut data = Vec::with_capacity(8192);
 	std::io::stdin().read_to_end(&mut data).unwrap();
-	feature_flags_run(data.as_ptr(), data.len());
+	feature_flags_test(&data, lightning_fuzz::utils::test_logger::Stdout {});
 }
 
 #[test]
@@ -70,7 +71,7 @@ fn run_test_cases() {
 	use std::sync::{atomic, Arc};
 	{
 		let data: Vec<u8> = vec![0];
-		feature_flags_run(data.as_ptr(), data.len());
+		feature_flags_test(&data, test_logger::DevNull {});
 	}
 	let mut threads = Vec::new();
 	let threads_running = Arc::new(atomic::AtomicUsize::new(0));