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

include/uc_priv.h

@@ -86,6 +86,7 @@ struct hook {
     int type;            // UC_HOOK_*
     int insn;            // instruction for HOOK_INSN
     int refs;            // reference count to free hook stored in multiple lists
+    bool to_delete;      // set to true when the hook is deleted by the user. The destruction of the hook is delayed.
     uint64_t begin, end; // only trigger if PC or memory access is in this address (depends on hook type)
     void *callback;      // a uc_cb_* type
     void *user_data;
@@ -212,6 +213,7 @@ struct uc_struct {
 
     // linked lists containing hooks per type
     struct list hook[UC_HOOK_MAX];
+    struct list hooks_to_del;
 
     // hook to count number of instructions for uc_emu_start()
     uc_hook count_hook;