src/lj_vmevent.c

   1 /*
   2 ** VM event handling.
   3 ** Copyright (C) 2005-2023 Mike Pall. See Copyright Notice in luajit.h
   4 */
   5
   6 #include <stdio.h>
   7
   8 #define lj_vmevent_c
   9 #define LUA_CORE
  10
  11 #include "lj_obj.h"
  12 #include "lj_str.h"
  13 #include "lj_tab.h"
  14 #include "lj_state.h"
  15 #include "lj_dispatch.h"
  16 #include "lj_vm.h"
  17 #include "lj_vmevent.h"
  18
  19 ptrdiff_t lj_vmevent_prepare(lua_State *L, VMEvent ev)
  20 {
  21   global_State *g = G(L);
  22   GCstr *s = lj_str_newlit(L, LJ_VMEVENTS_REGKEY);
  23   cTValue *tv = lj_tab_getstr(tabV(registry(L)), s);
  24   if (tvistab(tv)) {
  25     int hash = VMEVENT_HASH(ev);
  26     tv = lj_tab_getint(tabV(tv), hash);
  27     if (tv && tvisfunc(tv)) {
  28       lj_state_checkstack(L, LUA_MINSTACK);
  29       setfuncV(L, L->top++, funcV(tv));
  30       if (LJ_FR2) setnilV(L->top++);
  31       return savestack(L, L->top);
  32     }
  33   }
  34   g->vmevmask &= ~VMEVENT_MASK(ev);  /* No handler: cache this fact. */
  35   return 0;
  36 }
  37
  38 void lj_vmevent_call(lua_State *L, ptrdiff_t argbase)
  39 {
  40   global_State *g = G(L);
  41   uint8_t oldmask = g->vmevmask;
  42   uint8_t oldh = hook_save(g);
  43   int status;
  44   g->vmevmask = 0;  /* Disable all events. */
  45   hook_vmevent(g);
  46   status = lj_vm_pcall(L, restorestack(L, argbase), 0+1, 0);
  47   if (LJ_UNLIKELY(status)) {
  48     /* Really shouldn't use stderr here, but where else to complain? */
  49     L->top--;
  50     fputs("VM handler failed: ", stderr);
  51     fputs(tvisstr(L->top) ? strVdata(L->top) : "?", stderr);
  52     fputc('\n', stderr);
  53   }
  54   hook_restore(g, oldh);
  55   if (g->vmevmask != VMEVENT_NOCACHE)
  56     g->vmevmask = oldmask;  /* Restore event mask, but not if not modified. */
  57 }
  58