add helper function to delete a workdir safely

fuzz_runner/src/nyx/qemu_process.rs

@@ -569,3 +569,38 @@ impl QemuProcess {
         (shm_work_dir_path, file_lock)
     }
 }
+
+/* Helper function to remove a Nyx workdir safely. Returns an error if 
+ * expected sub dirs are missing or the path does not exist */
+pub fn remove_workdir_safe(workdir: &str) -> Result<(), String> {
+    let folders = vec![
+        "/corpus/normal",
+        "/corpus/crash",
+        "/corpus/kasan",
+        "/corpus/timeout",
+        "/imports",
+        "/seeds",
+        "/snapshot",
+        "/forced_imports",
+    ];
+
+    if !Path::new(&format!("{}/", workdir)).exists() {
+        return Err(format!("\"{}/\" does not exists", workdir));
+    }
+
+    /* check if all sub dirs exists */
+    for folder in folders.iter() {
+        if !Path::new(&format!("{}/{}", workdir, folder)).exists() {
+            return Err(format!("\"{}/{}\" does not exists", workdir, folder));
+        }
+    }
+
+    /* remove if all sub dirs exists */
+    for folder in folders.iter() {
+        let _ = fs::remove_dir_all(format!("{}/{}", workdir, folder));
+    }
+
+    let _ = fs::remove_dir_all(workdir);
+
+    return Ok(());
+}

libnyx/src/ffi.rs

@@ -275,3 +275,24 @@ pub extern "C" fn nyx_set_hprintf_fd(nyx_process: * mut NyxProcess, fd: i32) {
         (*__nyx_process_check_ptr(nyx_process)).process.set_hprintf_fd(fd);
     }
 }
+
+/* Helper function to remove a given Nyx workdir safely.
+ * This function will return an error if the path does not exist or it does 
+ * not appear to be a Nyx workdir (e.g. specific sub directories are 
+ * missing). */
+#[no_mangle]
+pub extern "C" fn nyx_remove_work_dir(workdir: *const c_char) -> bool {
+    unsafe{
+        let workdir = CStr::from_ptr(workdir).to_str().unwrap();
+
+        match remove_work_dir(workdir) {
+            Ok(_) => {
+                true
+            },
+            Err(e) => {
+                eprintln!("[!] libnyx failed to remove workdir: {}", e);
+                false
+            }
+        }
+    }
+}

libnyx/src/lib.rs

@@ -367,3 +367,7 @@ impl NyxProcess {
     }
 
 }
+
+pub fn remove_work_dir(workdir: &str) -> Result<(), String> {
+    fuzz_runner::nyx::qemu_process::remove_workdir_safe(workdir)
+}

libnyx/test.c

@@ -59,6 +59,7 @@ void hexdump(void *mem, unsigned int len)
     }
 }
  
+#define WORKDIR_PATH "/tmp/wdir"
 
 int main(int argc, char** argv){
 
@@ -69,7 +70,7 @@ int main(int argc, char** argv){
 
     //nyx_config_debug(nyx_config);
 
-    nyx_config_set_workdir_path(nyx_config, "/tmp/wdir");
+    nyx_config_set_workdir_path(nyx_config, WORKDIR_PATH);
     nyx_config_set_input_buffer_size(nyx_config, 0x2000);
 
     int fd = open("/tmp/nyx_test_output.log", O_WRONLY | O_CREAT | O_TRUNC, 0644);
@@ -113,4 +114,9 @@ int main(int argc, char** argv){
     }
 
     nyx_shutdown(nyx_runner);
+
+    if(!nyx_remove_work_dir(WORKDIR_PATH) ){
+        printf("Error: Failed to remove work dir\n");
+    }
+
 }