Fix UAF when deleting hook while in hook callback #1127 (#1130)

* Handle the cpu context save in a more pythonic way, so the context can be serialized and reuse in an other process using the same emulator architecture and modes

* Fix type error ; mistakes a size_t uint64_t ; breaks in 32bit...

* Fix the UAF situation when deleting a hook while being in a hook callback. Added an attribute 'to_delete' to hooks, and a list hooks_to_del to delay the free of the hooks

* Minor fixes ; forgot return type of clear_deleted_hooks ; do not declare variable in for predicate

qemu/cpu-exec.c

@@ -135,6 +135,8 @@ int cpu_exec(struct uc_struct *uc, CPUArchState *env)   // qq
                         // Unicorn: call registered invalid instruction callbacks
                         HOOK_FOREACH_VAR_DECLARE;
                         HOOK_FOREACH(uc, hook, UC_HOOK_INSN_INVALID) {
+                            if (hook->to_delete)
+                                continue;
                             catched = ((uc_cb_hookinsn_invalid_t)hook->callback)(uc, hook->user_data);
                             if (catched)
                                 break;
@@ -145,6 +147,8 @@ int cpu_exec(struct uc_struct *uc, CPUArchState *env)   // qq
                         // Unicorn: call registered interrupt callbacks
                         HOOK_FOREACH_VAR_DECLARE;
                         HOOK_FOREACH(uc, hook, UC_HOOK_INTR) {
+                            if (hook->to_delete)
+                                continue;
                             ((uc_cb_hookintr_t)hook->callback)(uc, cpu->exception_index, hook->user_data);
                             catched = true;
                         }