4 files changed, 32 insertions, 8 deletions
diff --git a/frida_mode/src/js/api.js b/frida_mode/src/js/api.js
index 8e810d09..215fbdaf 100644
--- a/frida_mode/src/js/api.js
+++ b/frida_mode/src/js/api.js
@@ -151,6 +151,13 @@ class Afl {
         const buf = Memory.allocUtf8String(file);
         Afl.jsApiSetInstrumentUnstableCoverageFile(buf);
     }
+    /*
+     * Set a callback to be called in place of the usual `main` function. This see
+     * `Scripting.md` for details.
+     */
+    static setJsMainHook(address) {
+        Afl.jsApiSetJsMainHook(address);
+    }
     /**
      * This is equivalent to setting `AFL_FRIDA_PERSISTENT_ADDR`, again a
      * `NativePointer` should be provided as it's argument.
@@ -291,6 +298,7 @@ Afl.jsApiSetInstrumentSeed = Afl.jsApiGetFunction("js_api_set_instrument_seed",
 Afl.jsApiSetInstrumentTrace = Afl.jsApiGetFunction("js_api_set_instrument_trace", "void", []);
 Afl.jsApiSetInstrumentTraceUnique = Afl.jsApiGetFunction("js_api_set_instrument_trace_unique", "void", []);
 Afl.jsApiSetInstrumentUnstableCoverageFile = Afl.jsApiGetFunction("js_api_set_instrument_unstable_coverage_file", "void", ["pointer"]);
+Afl.jsApiSetJsMainHook = Afl.jsApiGetFunction("js_api_set_js_main_hook", "void", ["pointer"]);
 Afl.jsApiSetPersistentAddress = Afl.jsApiGetFunction("js_api_set_persistent_address", "void", ["pointer"]);
 Afl.jsApiSetPersistentCount = Afl.jsApiGetFunction("js_api_set_persistent_count", "void", ["uint64"]);
 Afl.jsApiSetPersistentDebug = Afl.jsApiGetFunction("js_api_set_persistent_debug", "void", []);
@@ -299,8 +307,8 @@ Afl.jsApiSetPersistentReturn = Afl.jsApiGetFunction("js_api_set_persistent_retur
 Afl.jsApiSetPrefetchBackpatchDisable = Afl.jsApiGetFunction("js_api_set_prefetch_backpatch_disable", "void", []);
 Afl.jsApiSetPrefetchDisable = Afl.jsApiGetFunction("js_api_set_prefetch_disable", "void", []);
 Afl.jsApiSetSeccompFile = Afl.jsApiGetFunction("js_api_set_seccomp_file", "void", ["pointer"]);
-Afl.jsApiSetStalkerCallback = Afl.jsApiGetFunction("js_api_set_stalker_callback", "void", ["pointer"]);
 Afl.jsApiSetStalkerAdjacentBlocks = Afl.jsApiGetFunction("js_api_set_stalker_adjacent_blocks", "void", ["uint32"]);
+Afl.jsApiSetStalkerCallback = Afl.jsApiGetFunction("js_api_set_stalker_callback", "void", ["pointer"]);
 Afl.jsApiSetStalkerIcEntries = Afl.jsApiGetFunction("js_api_set_stalker_ic_entries", "void", ["uint32"]);
 Afl.jsApiSetStatsFile = Afl.jsApiGetFunction("js_api_set_stats_file", "void", ["pointer"]);
 Afl.jsApiSetStatsInterval = Afl.jsApiGetFunction("js_api_set_stats_interval", "void", ["uint64"]);
diff --git a/frida_mode/src/js/js.c b/frida_mode/src/js/js.c
index 37cd377b..5f477388 100644
--- a/frida_mode/src/js/js.c
+++ b/frida_mode/src/js/js.c
@@ -3,10 +3,11 @@
 #include "js.h"
 #include "util.h"
 
-static char *             js_script = NULL;
 gboolean                  js_done = FALSE;
 js_api_stalker_callback_t js_user_callback = NULL;
+js_main_hook_t            js_main_hook = NULL;
 
+static char *              js_script = NULL;
 static gchar *             filename = "afl.js";
 static gchar *             contents;
 static GumScriptBackend *  backend;
diff --git a/frida_mode/src/js/js_api.c b/frida_mode/src/js/js_api.c
index 4221fb80..5021b531 100644
--- a/frida_mode/src/js/js_api.c
+++ b/frida_mode/src/js/js_api.c
@@ -255,3 +255,10 @@ __attribute__((visibility("default"))) void js_api_set_stalker_adjacent_blocks(
 
 }
 
+__attribute__((visibility("default"))) void js_api_set_js_main_hook(
+    const js_main_hook_t hook) {
+
+  js_main_hook = hook;
+
+}
+
diff --git a/frida_mode/src/main.c b/frida_mode/src/main.c
index cb88eabe..913e3a46 100644
--- a/frida_mode/src/main.c
+++ b/frida_mode/src/main.c
@@ -36,13 +36,13 @@
 extern mach_port_t mach_task_self();
 extern GumAddress  gum_darwin_find_entrypoint(mach_port_t task);
 #else
-extern int  __libc_start_main(int *(main)(int, char **, char **), int argc,
+extern int  __libc_start_main(int (*main)(int, char **, char **), int argc,
                               char **ubp_av, void (*init)(void),
                               void (*fini)(void), void (*rtld_fini)(void),
                               void(*stack_end));
 #endif
 
-typedef int *(*main_fn_t)(int argc, char **argv, char **envp);
+typedef int (*main_fn_t)(int argc, char **argv, char **envp);
 
 static main_fn_t main_fn = NULL;
 
@@ -217,7 +217,7 @@ __attribute__((visibility("default"))) void afl_frida_start(void) {
 
 }
 
-static int *on_main(int argc, char **argv, char **envp) {
+static int on_main(int argc, char **argv, char **envp) {
 
   on_main_os(argc, argv, envp);
 
@@ -225,12 +225,20 @@ static int *on_main(int argc, char **argv, char **envp) {
 
   afl_frida_start();
 
-  return main_fn(argc, argv, envp);
+  if (js_main_hook != NULL) {
+
+    return js_main_hook(argc, argv, envp);
+
+  } else {
+
+    return main_fn(argc, argv, envp);
+
+  }
 
 }
 
 #if defined(EMBEDDED)
-extern int *main(int argc, char **argv, char **envp);
+extern int main(int argc, char **argv, char **envp);
 
 static void intercept_main(void) {
 
@@ -253,7 +261,7 @@ static void intercept_main(void) {
 }
 
 #else
-static int on_libc_start_main(int *(main)(int, char **, char **), int argc,
+static int on_libc_start_main(int (*main)(int, char **, char **), int argc,
                               char **ubp_av, void (*init)(void),
                               void (*fini)(void), void (*rtld_fini)(void),
                               void(*stack_end)) {