clippy, cfg fuzzing, docs

Author: vanhauser-thc

README.md

@@ -51,3 +51,22 @@ environment variable `AFL_NO_CFG_FUZZING` to `1` when building.
 [american-fuzzy-lop]: http://lcamtuf.coredump.cx/afl/
 [AFLplusplus]: https://aflplus.plus/
 [rust]: https://www.rust-lang.org
+
+## IJON
+
+If you want to use IJON - helping fuzzer coverage through code annotation - then
+have a look at the [maze example](afl/examples/maze.rs) how to use it.
+
+You can find the AFL++ IJON documentation at [https://github.com/AFLplusplus/AFLplusplus/blob/stable/docs/IJON.md](https://github.com/AFLplusplus/AFLplusplus/blob/stable/docs/IJON.md)
+
+Note that the IJON macros have been rustyfied to lowercase - hence `IJON_MAX(x)` is `ijon_max(x)` in Rust.
+
+You will need to the following parts of cargo AFL:
+
+```
+use afl::ijon_hashint;
+use afl::ijon_hashstr;
+use std::ffi::CString;
+```
+
+plus any macros that you use, e.g. `afl::ijon_max`.

afl/examples/maze.rs

@@ -197,6 +197,7 @@ fn main() {
                 panic!("Exited the maze!");
             }
 
+            #[cfg(fuzzing)]
             ijon_set!(ijon_hashint(pos.0 as u32, pos.1 as u32));
         }
     });

cargo-afl/tests/integration.rs

@@ -62,6 +62,7 @@ fn integration_cfg() {
 #[test]
 fn integration_maze() {
     if !common::plugins_available().unwrap_or_default() {
+        #[allow(clippy::explicit_write)]
         writeln!(
             std::io::stderr(),
             "Skipping `integration_maze` test as plugins are unavailable"