3 files changed, 34 insertions, 25 deletions
diff --git a/examples/custom_mutators/Makefile b/examples/custom_mutators/Makefile
index a83e87fe..463cefb1 100644
--- a/examples/custom_mutators/Makefile
+++ b/examples/custom_mutators/Makefile
@@ -1,2 +1,7 @@
-all:
+all: libexamplemutator.so
+
+libexamplemutator.so:
 	$(CC) $(CFLAGS) -fPIC -shared -g -I ../../include example.c -o libexamplemutator.so
+
+clean:
+	rm -rf libexamplemutator.so
diff --git a/examples/custom_mutators/example.c b/examples/custom_mutators/example.c
index a9764f5b..c8200b26 100644
--- a/examples/custom_mutators/example.c
+++ b/examples/custom_mutators/example.c
@@ -142,32 +142,25 @@ size_t afl_custom_fuzz(my_mutator_t *data, uint8_t *buf, size_t buf_size,
 size_t afl_custom_pre_save(my_mutator_t *data, uint8_t *buf, size_t buf_size,
                            uint8_t **out_buf) {
 
-  if (data->pre_save_size < buf_size + 5) {
+  uint8_t *pre_save_buf = maybe_grow(BUF_PARAMS(data, pre_save), buf_size + 5);
+  if (!pre_save_buf) {
 
-    data->pre_save_buf = maybe_grow(BUF_PARAMS(data, pre_save), buf_size + 5);
-    if (!data->pre_save_buf) {
-
-      perror("custom mutator realloc failed.");
-      *out_buf = NULL;
-      return 0;
-
-    }
-
-    data->pre_save_size = buf_size + 5;
+    perror("custom mutator realloc failed.");
+    *out_buf = NULL;
+    return 0;
 
   }
 
-  *out_buf = data->pre_save_buf;
+  memcpy(pre_save_buf + 5, buf, buf_size);
+  pre_save_buf[0] = 'A';
+  pre_save_buf[1] = 'F';
+  pre_save_buf[2] = 'L';
+  pre_save_buf[3] = '+';
+  pre_save_buf[4] = '+';
 
-  memcpy(*out_buf + 5, buf, buf_size);
-  size_t out_buf_size = buf_size + 5;
-  *out_buf[0] = 'A';
-  *out_buf[1] = 'F';
-  *out_buf[2] = 'L';
-  *out_buf[3] = '+';
-  *out_buf[4] = '+';
+  *out_buf = pre_save_buf;
 
-  return out_buf_size;
+  return buf_size + 5;
 
 }
 
diff --git a/examples/custom_mutators/example.py b/examples/custom_mutators/example.py
index 6bacfa05..9e95eed6 100644
--- a/examples/custom_mutators/example.py
+++ b/examples/custom_mutators/example.py
@@ -17,6 +17,13 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
 import random
 
 
+COMMANDS = [
+    b"GET",
+    b"PUT",
+    b"DEL",
+]
+
+
 def init(seed):
     '''
     Called once when AFLFuzz starts up. Used to seed our RNG.
@@ -27,6 +34,10 @@ def init(seed):
     random.seed(seed)
 
 
+def deinit():
+    pass
+
+
 def fuzz(buf, add_buf, max_size):
     '''
     Called per fuzzing iteration.
@@ -44,8 +55,9 @@ def fuzz(buf, add_buf, max_size):
     @rtype: bytearray
     @return: A new bytearray containing the mutated data
     '''
-    ret = bytearray(buf)
-    # Do something interesting with ret
+    ret = bytearray(100)
+
+    ret[:3] = random.choice(COMMANDS)
 
     return ret
 
@@ -164,11 +176,10 @@ def fuzz(buf, add_buf, max_size):
 #     '''
 #     Called after adding a new test case to the queue
 #
-#     @type filename_new_queue: str 
+#     @type filename_new_queue: str
 #     @param filename_new_queue: File name of the new queue entry
 #
 #     @type filename_orig_queue: str
 #     @param filename_orig_queue: File name of the original queue entry
 #     '''
 #     pass
-