impl vercmp fuzzer

fuzz/atom/vercmp/fuzz.rs

@@ -0,0 +1,112 @@
+use core::slice;
+use gentoo_utils::{
+    Parseable,
+    atom::{Atom, Version},
+};
+use mon::{Parser, ParserFinishedError, input::InputIter};
+use std::{
+    cmp::Ordering,
+    io::{BufRead, BufReader, Write},
+    process::{ChildStdin, ChildStdout, Command, Stdio},
+    sync::{LazyLock, Mutex},
+};
+
+struct PyProcess {
+    stdin: Mutex<ChildStdin>,
+    stdout: Mutex<BufReader<ChildStdout>>,
+    buffer: Mutex<String>,
+}
+
+#[allow(clippy::missing_safety_doc, clippy::needless_return)]
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn LLVMFuzzerTestOneInput(input: *const u8, len: usize) -> i32 {
+    static PY_PROCESS: LazyLock<PyProcess> = LazyLock::new(|| {
+        #[allow(clippy::zombie_processes)]
+        let mut proc = Command::new("vercmp.py")
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::inherit())
+            .spawn()
+            .expect("failed to spawn vercmp.py");
+
+        let stdin = Mutex::new(proc.stdin.take().unwrap());
+        let stdout = Mutex::new(BufReader::new(proc.stdout.take().unwrap()));
+
+        PyProcess {
+            stdin,
+            stdout,
+            buffer: Mutex::new(String::new()),
+        }
+    });
+
+    let control = Version::parser()
+        .parse_finished(InputIter::new("1.2.0a_alpha1_beta2-r1-8"))
+        .unwrap();
+
+    let slice = unsafe { slice::from_raw_parts(input, len) };
+
+    if slice.iter().any(|b| !b.is_ascii_graphic()) {
+        return -1;
+    }
+
+    let str = match str::from_utf8(slice) {
+        Ok(str) => str,
+        Err(_) => return -1,
+    };
+
+    let version_str = match str.split_ascii_whitespace().nth(0) {
+        Some(lhs) => lhs,
+        None => return -1,
+    };
+
+    dbg!(version_str);
+
+    let version = match Version::parser().parse_finished(InputIter::new(version_str)) {
+        Ok(a) => a,
+        Err(_) => return -1,
+    };
+
+    let gentoo_utils = control.cmp(&version);
+
+    let portage_result = portage_vercmp(&PY_PROCESS, &control, &version);
+
+    match portage_result {
+        Ok(portage) if portage == gentoo_utils => {
+            eprintln!("agreement on {control} cmp {version} == {portage:?}");
+        }
+        Ok(portage) => {
+            panic!(
+                "disagreement on {control} == {version}:\nportage:{portage:?} gentoo_utils:{gentoo_utils:?}"
+            )
+        }
+        Err(_) => {
+            panic!("parsed invalid versions: {control} | {version}")
+        }
+    }
+
+    return 0;
+}
+
+fn portage_vercmp(pyproc: &PyProcess, a: &Version, b: &Version) -> Result<Ordering, ()> {
+    let mut stdin = pyproc.stdin.lock().expect("failed to get stdin lock");
+    let mut stdout = pyproc.stdout.lock().expect("failed to get stdout lock");
+    let mut buffer = pyproc.buffer.lock().expect("failed to get buffer lock");
+
+    writeln!(&mut stdin, "{a} {b}").expect("failed to write line to python process");
+
+    stdin.flush().unwrap();
+
+    buffer.clear();
+
+    stdout
+        .read_line(&mut buffer)
+        .expect("failed to read line from python process");
+
+    match buffer.as_str().trim() {
+        "0" => Ok(Ordering::Equal),
+        "1" => Ok(Ordering::Greater),
+        "-1" => Ok(Ordering::Less),
+        "err" => Err(()),
+        other => panic!("unexpected result from python: {other}"),
+    }
+}