From 8f4b8840c41aa62fd15b655f08f838b02e98ccdc Mon Sep 17 00:00:00 2001
From: Martin Lindhe <martin-commit@ubique.se>
Date: Sun, 5 May 2019 19:42:48 +0200
Subject: [PATCH] png-afl: document usage and minor tweaks, fixes #132

---
 png-afl/.gitignore  |  1 +
 png-afl/Cargo.toml  |  5 +++--
 png-afl/README.md   | 18 ++++++++++++++++++
 png-afl/src/main.rs |  6 +++---
 4 files changed, 25 insertions(+), 5 deletions(-)
 create mode 100644 png-afl/.gitignore
 create mode 100644 png-afl/README.md

diff --git a/png-afl/.gitignore b/png-afl/.gitignore
new file mode 100644
index 00000000..1fcb1529
--- /dev/null
+++ b/png-afl/.gitignore
@@ -0,0 +1 @@
+out
diff --git a/png-afl/Cargo.toml b/png-afl/Cargo.toml
index 310d6447..5f034397 100644
--- a/png-afl/Cargo.toml
+++ b/png-afl/Cargo.toml
@@ -4,7 +4,8 @@ version = "0.2.0"
 authors = ["Sergey Davidoff <shnatsel@gmail.com>", "Paul Grandperrin <paul.grandperrin@gmail.com>"]
 
 [dependencies]
-afl = "0.4.0"
+afl = "0.4.3"
 png = {path = "../"}
 
-
+[features]
+fuzzing = []
diff --git a/png-afl/README.md b/png-afl/README.md
new file mode 100644
index 00000000..720ffb8f
--- /dev/null
+++ b/png-afl/README.md
@@ -0,0 +1,18 @@
+
+## Build fuzzer binary
+
+RUSTFLAGS='-C codegen-units=1' cargo afl build
+
+NOTE: the RUSTFLAGS is only needed on Linux (and not if using gold linker), see https://github.com/rust-lang/rust/issues/53945
+
+
+## Run fuzzer
+
+    cargo afl fuzz -m 200 -i fuzzing_seeds -o out target/debug/png-afl
+
+NOTE: -m 200 sets memory limit to 200 mb. afl defaults to 50 megabytes memory usage. If we would not increase it, many invocations will exit with SIGABRT and look like crashes.
+
+
+### More info
+
+https://rust-fuzz.github.io/book/afl/tutorial.html
diff --git a/png-afl/src/main.rs b/png-afl/src/main.rs
index dc507dcf..b3b66130 100644
--- a/png-afl/src/main.rs
+++ b/png-afl/src/main.rs
@@ -1,3 +1,4 @@
+#[macro_use]
 extern crate afl;
 extern crate png;
 
@@ -25,8 +26,7 @@ fn png_decode(data: &[u8]) -> Result<(png::OutputInfo, Vec<u8>), ()> {
 }
 
 fn main() {
-    afl::fuzz(|data| {
-    //afl::read_stdio_bytes(|data| {
-        png_decode(&data);
+    fuzz!(|data: &[u8]| {
+        let _ = png_decode(&data);
     });
 }