1 files changed, 74 insertions, 0 deletions
diff --git a/custom_mutators/examples/simple_example.c b/custom_mutators/examples/simple_example.c
new file mode 100644
index 00000000..d888ec1f
--- /dev/null
+++ b/custom_mutators/examples/simple_example.c
@@ -0,0 +1,74 @@
+// This simple example just creates random buffer <= 100 filled with 'A'
+// needs -I /path/to/AFLplusplus/include
+#include "custom_mutator_helpers.h"
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+#ifndef _FIXED_CHAR
+  #define _FIXED_CHAR 0x41
+#endif
+
+typedef struct my_mutator {
+
+  afl_t *afl;
+
+  // Reused buffers:
+  BUF_VAR(u8, fuzz);
+
+} my_mutator_t;
+
+my_mutator_t *afl_custom_init(afl_t *afl, unsigned int seed) {
+
+  srand(seed);
+  my_mutator_t *data = calloc(1, sizeof(my_mutator_t));
+  if (!data) {
+
+    perror("afl_custom_init alloc");
+    return NULL;
+
+  }
+
+  data->afl = afl;
+
+  return data;
+
+}
+
+size_t afl_custom_fuzz(my_mutator_t *data, uint8_t *buf, size_t buf_size,
+                       u8 **out_buf, uint8_t *add_buf,
+                       size_t add_buf_size,  // add_buf can be NULL
+                       size_t max_size) {
+
+  int size = (rand() % 100) + 1;
+  if (size > max_size) size = max_size;
+  u8 *mutated_out = maybe_grow(BUF_PARAMS(data, fuzz), size);
+  if (!mutated_out) {
+
+    *out_buf = NULL;
+    perror("custom mutator allocation (maybe_grow)");
+    return 0;            /* afl-fuzz will very likely error out after this. */
+
+  }
+
+  memset(mutated_out, _FIXED_CHAR, size);
+
+  *out_buf = mutated_out;
+  return size;
+
+}
+
+/**
+ * Deinitialize everything
+ *
+ * @param data The data ptr from afl_custom_init
+ */
+void afl_custom_deinit(my_mutator_t *data) {
+
+  free(data->fuzz_buf);
+  free(data);
+
+}
+