Debug output for forkserver (#413)

* usability fixes for forkserver

* don't call target_bytes twice in TimeoutForkserverExecutor

* don't call target_bytes twice in ForkserverExecutor

libafl/src/executors/forkserver.rs

@@ -195,15 +195,22 @@ impl Forkserver {
         out_filefd: RawFd,
         use_stdin: bool,
         memlimit: u64,
+        debug_output: bool,
     ) -> Result<Self, Error> {
         let mut st_pipe = Pipe::new().unwrap();
         let mut ctl_pipe = Pipe::new().unwrap();
 
+        let (stdout, stderr) = if debug_output {
+            (Stdio::inherit(), Stdio::inherit())
+        } else {
+            (Stdio::null(), Stdio::null())
+        };
+
         match Command::new(target)
             .args(args)
             .stdin(Stdio::null())
-            .stdout(Stdio::null())
-            .stderr(Stdio::null())
+            .stdout(stdout)
+            .stderr(stderr)
             .env("LD_BIND_LAZY", "1")
             .setlimit(memlimit)
             .setsid()
@@ -364,12 +371,13 @@ where
 
         match &mut self.executor.map_mut() {
             Some(map) => {
-                let size = input.target_bytes().as_slice().len();
+                let target_bytes = input.target_bytes();
+                let size = target_bytes.as_slice().len();
                 let size_in_bytes = size.to_ne_bytes();
                 // The first four bytes tells the size of the shmem.
                 map.map_mut()[..4].copy_from_slice(&size_in_bytes[..4]);
                 map.map_mut()[SHMEM_FUZZ_HDR_SIZE..(SHMEM_FUZZ_HDR_SIZE + size)]
-                    .copy_from_slice(input.target_bytes().as_slice());
+                    .copy_from_slice(target_bytes.as_slice());
             }
             None => {
                 self.executor
@@ -466,6 +474,16 @@ where
         arguments: &[String],
         use_shmem_testcase: bool,
         observers: OT,
+    ) -> Result<Self, Error> {
+        Self::with_debug(target, arguments, use_shmem_testcase, observers, false)
+    }
+
+    pub fn with_debug(
+        target: String,
+        arguments: &[String],
+        use_shmem_testcase: bool,
+        observers: OT,
+        debug_output: bool,
     ) -> Result<Self, Error> {
         let mut args = Vec::<String>::new();
         let mut use_stdin = true;
@@ -500,6 +518,7 @@ where
             out_file.as_raw_fd(),
             use_stdin,
             0,
+            debug_output,
         )?;
 
         let (rlen, status) = forkserver.read_st()?; // Initial handshake, read 4-bytes hello message from the forkserver.
@@ -573,12 +592,13 @@ where
         // Write to testcase
         match &mut self.map {
             Some(map) => {
-                let size = input.target_bytes().as_slice().len();
+                let target_bytes = input.target_bytes();
+                let size = target_bytes.as_slice().len();
                 let size_in_bytes = size.to_ne_bytes();
                 // The first four bytes tells the size of the shmem.
                 map.map_mut()[..4].copy_from_slice(&size_in_bytes[..4]);
                 map.map_mut()[SHMEM_FUZZ_HDR_SIZE..(SHMEM_FUZZ_HDR_SIZE + size)]
-                    .copy_from_slice(input.target_bytes().as_slice());
+                    .copy_from_slice(target_bytes.as_slice());
             }
             None => {
                 self.out_file.write_buf(input.target_bytes().as_slice());

libafl_sugar/src/forkserver.rs

@@ -31,10 +31,10 @@ use libafl::{
 
 use crate::{CORPUS_CACHE_SIZE, DEFAULT_TIMEOUT_SECS};
 
-pub const MAP_SIZE: usize = 65536;
+pub const DEFAULT_MAP_SIZE: usize = 65536;
 
 #[derive(TypedBuilder)]
-pub struct ForkserverBytesCoverageSugar<'a> {
+pub struct ForkserverBytesCoverageSugar<'a, const MAP_SIZE: usize> {
     /// Laucher configuration (default is random)
     #[builder(default = None, setter(strip_option))]
     configuration: Option<String>,
@@ -66,13 +66,13 @@ pub struct ForkserverBytesCoverageSugar<'a> {
     #[builder(default = false)]
     /// Use shared mem testcase delivery
     shmem_testcase: bool,
-    // Coverage map size
-    //#[builder(default = MAP_SIZE)]
-    //map_size: usize,
+    #[builder(default = false)]
+    /// Print target program output
+    debug_output: bool,
 }
 
 #[allow(clippy::similar_names)]
-impl<'a> ForkserverBytesCoverageSugar<'a> {
+impl<'a, const MAP_SIZE: usize> ForkserverBytesCoverageSugar<'a, MAP_SIZE> {
     #[allow(clippy::too_many_lines, clippy::similar_names)]
     pub fn run(&mut self) {
         let conf = match self.configuration.as_ref() {
@@ -166,11 +166,12 @@ impl<'a> ForkserverBytesCoverageSugar<'a> {
 
             // Create the executor for an in-process function with one observer for edge coverage and one for the execution time
             let mut executor = TimeoutForkserverExecutor::new(
-                ForkserverExecutor::new(
+                ForkserverExecutor::with_debug(
                     self.program.clone(),
                     self.arguments,
                     self.shmem_testcase,
                     tuple_list!(edges_observer, time_observer),
+                    self.debug_output,
                 )
                 .expect("Failed to create the executor."),
                 timeout,
@@ -248,16 +249,14 @@ impl<'a> ForkserverBytesCoverageSugar<'a> {
     }
 }
 
-/*
 #[cfg(feature = "python")]
 pub mod pybind {
-    use crate::inmemory;
+    use crate::forkserver;
     use pyo3::prelude::*;
-    use pyo3::types::PyBytes;
     use std::path::PathBuf;
 
     #[pyclass(unsendable)]
-    struct InMemoryBytesCoverageSugar {
+    struct ForkserverBytesCoverageSugar {
         input_dirs: Vec<PathBuf>,
         output_dir: PathBuf,
         broker_port: u16,
@@ -265,7 +264,7 @@ pub mod pybind {
     }
 
     #[pymethods]
-    impl InMemoryBytesCoverageSugar {
+    impl ForkserverBytesCoverageSugar {
         #[new]
         fn new(
             input_dirs: Vec<PathBuf>,
@@ -282,27 +281,21 @@ pub mod pybind {
         }
 
         #[allow(clippy::needless_pass_by_value)]
-        pub fn run(&self, harness: PyObject) {
-            inmemory::InMemoryBytesCoverageSugar::builder()
+        pub fn run(&self, program: String, arguments: Vec<String>) {
+            forkserver::ForkserverBytesCoverageSugar::<{ forkserver::DEFAULT_MAP_SIZE }>::builder()
                 .input_dirs(&self.input_dirs)
                 .output_dir(self.output_dir.clone())
                 .broker_port(self.broker_port)
                 .cores(&self.cores)
-                .harness(|buf| {
-                    Python::with_gil(|py| -> PyResult<()> {
-                        let args = (PyBytes::new(py, buf),); // TODO avoid copy
-                        harness.call1(py, args)?;
-                        Ok(())
-                    })
-                    .unwrap();
-                })
+                .program(program)
+                .arguments(&arguments)
                 .build()
                 .run();
         }
     }
 
     pub fn register(_py: Python, m: &PyModule) -> PyResult<()> {
-        m.add_class::<InMemoryBytesCoverageSugar>()?;
+        m.add_class::<ForkserverBytesCoverageSugar>()?;
         Ok(())
     }
-}*/
+}