src/lib_ffi.c

   1 /*
   2 ** FFI library.
   3 ** Copyright (C) 2005-2012 Mike Pall. See Copyright Notice in luajit.h
   4 */
   5
   6 #define lib_ffi_c
   7 #define LUA_LIB
   8
   9 #include <errno.h>
  10
  11 #include "lua.h"
  12 #include "lauxlib.h"
  13 #include "lualib.h"
  14
  15 #include "lj_obj.h"
  16
  17 #if LJ_HASFFI
  18
  19 #include "lj_gc.h"
  20 #include "lj_err.h"
  21 #include "lj_str.h"
  22 #include "lj_tab.h"
  23 #include "lj_meta.h"
  24 #include "lj_ctype.h"
  25 #include "lj_cparse.h"
  26 #include "lj_cdata.h"
  27 #include "lj_cconv.h"
  28 #include "lj_carith.h"
  29 #include "lj_ccall.h"
  30 #include "lj_ccallback.h"
  31 #include "lj_clib.h"
  32 #include "lj_ff.h"
  33 #include "lj_lib.h"
  34
  35 /* -- C type checks ------------------------------------------------------- */
  36
  37 /* Check first argument for a C type and returns its ID. */
  38 static CTypeID ffi_checkctype(lua_State *L, CTState *cts, TValue *param)
  39 {
  40   TValue *o = L->base;
  41   if (!(o < L->top)) {
  42   err_argtype:
  43     lj_err_argtype(L, 1, "C type");
  44   }
  45   if (tvisstr(o)) {  /* Parse an abstract C type declaration. */
  46     GCstr *s = strV(o);
  47     CPState cp;
  48     int errcode;
  49     cp.L = L;
  50     cp.cts = cts;
  51     cp.srcname = strdata(s);
  52     cp.p = strdata(s);
  53     cp.param = param;
  54     cp.mode = CPARSE_MODE_ABSTRACT|CPARSE_MODE_NOIMPLICIT;
  55     errcode = lj_cparse(&cp);
  56     if (errcode) lj_err_throw(L, errcode);  /* Propagate errors. */
  57     return cp.val.id;
  58   } else {
  59     GCcdata *cd;
  60     if (!tviscdata(o)) goto err_argtype;
  61     if (param && param < L->top) lj_err_arg(L, 1, LJ_ERR_FFI_NUMPARAM);
  62     cd = cdataV(o);
  63     return cd->ctypeid == CTID_CTYPEID ? *(CTypeID *)cdataptr(cd) : cd->ctypeid;
  64   }
  65 }
  66
  67 /* Check argument for C data and return it. */
  68 static GCcdata *ffi_checkcdata(lua_State *L, int narg)
  69 {
  70   TValue *o = L->base + narg-1;
  71   if (!(o < L->top && tviscdata(o)))
  72     lj_err_argt(L, narg, LUA_TCDATA);
  73   return cdataV(o);
  74 }
  75
  76 /* Convert argument to C pointer. */
  77 static void *ffi_checkptr(lua_State *L, int narg, CTypeID id)
  78 {
  79   CTState *cts = ctype_cts(L);
  80   TValue *o = L->base + narg-1;
  81   void *p;
  82   if (o >= L->top)
  83     lj_err_arg(L, narg, LJ_ERR_NOVAL);
  84   lj_cconv_ct_tv(cts, ctype_get(cts, id), (uint8_t *)&p, o, CCF_ARG(narg));
  85   return p;
  86 }
  87
  88 /* Convert argument to int32_t. */
  89 static int32_t ffi_checkint(lua_State *L, int narg)
  90 {
  91   CTState *cts = ctype_cts(L);
  92   TValue *o = L->base + narg-1;
  93   int32_t i;
  94   if (o >= L->top)
  95     lj_err_arg(L, narg, LJ_ERR_NOVAL);
  96   lj_cconv_ct_tv(cts, ctype_get(cts, CTID_INT32), (uint8_t *)&i, o,
  97                  CCF_ARG(narg));
  98   return i;
  99 }
 100
 101 /* -- C type metamethods -------------------------------------------------- */
 102
 103 #define LJLIB_MODULE_ffi_meta
 104
 105 /* Handle ctype __index/__newindex metamethods. */
 106 static int ffi_index_meta(lua_State *L, CTState *cts, CType *ct, MMS mm)
 107 {
 108   CTypeID id = ctype_typeid(cts, ct);
 109   cTValue *tv = lj_ctype_meta(cts, id, mm);
 110   TValue *base = L->base;
 111   if (!tv) {
 112     const char *s;
 113   err_index:
 114     s = strdata(lj_ctype_repr(L, id, NULL));
 115     if (tvisstr(L->base+1)) {
 116       lj_err_callerv(L, LJ_ERR_FFI_BADMEMBER, s, strVdata(L->base+1));
 117     } else {
 118       const char *key = tviscdata(L->base+1) ?
 119         strdata(lj_ctype_repr(L, cdataV(L->base+1)->ctypeid, NULL)) :
 120         lj_typename(L->base+1);
 121       lj_err_callerv(L, LJ_ERR_FFI_BADIDXW, s, key);
 122     }
 123   }
 124   if (!tvisfunc(tv)) {
 125     if (mm == MM_index) {
 126       cTValue *o = lj_meta_tget(L, tv, base+1);
 127       if (o) {
 128         if (tvisnil(o)) goto err_index;
 129         copyTV(L, L->top-1, o);
 130         return 1;
 131       }
 132     } else {
 133       TValue *o = lj_meta_tset(L, tv, base+1);
 134       if (o) {
 135         copyTV(L, o, base+2);
 136         return 0;
 137       }
 138     }
 139     tv = L->top-1;
 140   }
 141   return lj_meta_tailcall(L, tv);
 142 }
 143
 144 LJLIB_CF(ffi_meta___index)      LJLIB_REC(cdata_index 0)
 145 {
 146   CTState *cts = ctype_cts(L);
 147   CTInfo qual = 0;
 148   CType *ct;
 149   uint8_t *p;
 150   TValue *o = L->base;
 151   if (!(o+1 < L->top && tviscdata(o)))  /* Also checks for presence of key. */
 152     lj_err_argt(L, 1, LUA_TCDATA);
 153   ct = lj_cdata_index(cts, cdataV(o), o+1, &p, &qual);
 154   if ((qual & 1))
 155     return ffi_index_meta(L, cts, ct, MM_index);
 156   if (lj_cdata_get(cts, ct, L->top-1, p))
 157     lj_gc_check(L);
 158   return 1;
 159 }
 160
 161 LJLIB_CF(ffi_meta___newindex)   LJLIB_REC(cdata_index 1)
 162 {
 163   CTState *cts = ctype_cts(L);
 164   CTInfo qual = 0;
 165   CType *ct;
 166   uint8_t *p;
 167   TValue *o = L->base;
 168   if (!(o+2 < L->top && tviscdata(o)))  /* Also checks for key and value. */
 169     lj_err_argt(L, 1, LUA_TCDATA);
 170   ct = lj_cdata_index(cts, cdataV(o), o+1, &p, &qual);
 171   if ((qual & 1)) {
 172     if ((qual & CTF_CONST))
 173       lj_err_caller(L, LJ_ERR_FFI_WRCONST);
 174     return ffi_index_meta(L, cts, ct, MM_newindex);
 175   }
 176   lj_cdata_set(cts, ct, p, o+2, qual);
 177   return 0;
 178 }
 179
 180 /* Common handler for cdata arithmetic. */
 181 static int ffi_arith(lua_State *L)
 182 {
 183   MMS mm = (MMS)(curr_func(L)->c.ffid - (int)FF_ffi_meta___eq + (int)MM_eq);
 184   return lj_carith_op(L, mm);
 185 }
 186
 187 /* The following functions must be in contiguous ORDER MM. */
 188 LJLIB_CF(ffi_meta___eq)         LJLIB_REC(cdata_arith MM_eq)
 189 {
 190   return ffi_arith(L);
 191 }
 192
 193 LJLIB_CF(ffi_meta___len)        LJLIB_REC(cdata_arith MM_len)
 194 {
 195   return ffi_arith(L);
 196 }
 197
 198 LJLIB_CF(ffi_meta___lt)         LJLIB_REC(cdata_arith MM_lt)
 199 {
 200   return ffi_arith(L);
 201 }
 202
 203 LJLIB_CF(ffi_meta___le)         LJLIB_REC(cdata_arith MM_le)
 204 {
 205   return ffi_arith(L);
 206 }
 207
 208 LJLIB_CF(ffi_meta___concat)     LJLIB_REC(cdata_arith MM_concat)
 209 {
 210   return ffi_arith(L);
 211 }
 212
 213 /* Forward declaration. */
 214 static int lj_cf_ffi_new(lua_State *L);
 215
 216 LJLIB_CF(ffi_meta___call)       LJLIB_REC(cdata_call)
 217 {
 218   CTState *cts = ctype_cts(L);
 219   GCcdata *cd = ffi_checkcdata(L, 1);
 220   CTypeID id = cd->ctypeid;
 221   CType *ct;
 222   cTValue *tv;
 223   MMS mm = MM_call;
 224   if (cd->ctypeid == CTID_CTYPEID) {
 225     id = *(CTypeID *)cdataptr(cd);
 226     mm = MM_new;
 227   } else {
 228     int ret = lj_ccall_func(L, cd);
 229     if (ret >= 0)
 230       return ret;
 231   }
 232   /* Handle ctype __call/__new metamethod. */
 233   ct = ctype_raw(cts, id);
 234   if (ctype_isptr(ct->info)) id = ctype_cid(ct->info);
 235   tv = lj_ctype_meta(cts, id, mm);
 236   if (tv)
 237     return lj_meta_tailcall(L, tv);
 238   else if (mm == MM_call)
 239     lj_err_callerv(L, LJ_ERR_FFI_BADCALL, strdata(lj_ctype_repr(L, id, NULL)));
 240   return lj_cf_ffi_new(L);
 241 }
 242
 243 LJLIB_CF(ffi_meta___add)        LJLIB_REC(cdata_arith MM_add)
 244 {
 245   return ffi_arith(L);
 246 }
 247
 248 LJLIB_CF(ffi_meta___sub)        LJLIB_REC(cdata_arith MM_sub)
 249 {
 250   return ffi_arith(L);
 251 }
 252
 253 LJLIB_CF(ffi_meta___mul)        LJLIB_REC(cdata_arith MM_mul)
 254 {
 255   return ffi_arith(L);
 256 }
 257
 258 LJLIB_CF(ffi_meta___div)        LJLIB_REC(cdata_arith MM_div)
 259 {
 260   return ffi_arith(L);
 261 }
 262
 263 LJLIB_CF(ffi_meta___mod)        LJLIB_REC(cdata_arith MM_mod)
 264 {
 265   return ffi_arith(L);
 266 }
 267
 268 LJLIB_CF(ffi_meta___pow)        LJLIB_REC(cdata_arith MM_pow)
 269 {
 270   return ffi_arith(L);
 271 }
 272
 273 LJLIB_CF(ffi_meta___unm)        LJLIB_REC(cdata_arith MM_unm)
 274 {
 275   return ffi_arith(L);
 276 }
 277 /* End of contiguous ORDER MM. */
 278
 279 LJLIB_CF(ffi_meta___tostring)
 280 {
 281   GCcdata *cd = ffi_checkcdata(L, 1);
 282   const char *msg = "cdata<%s>: %p";
 283   CTypeID id = cd->ctypeid;
 284   void *p = cdataptr(cd);
 285   if (id == CTID_CTYPEID) {
 286     msg = "ctype<%s>";
 287     id = *(CTypeID *)p;
 288   } else {
 289     CTState *cts = ctype_cts(L);
 290     CType *ct = ctype_raw(cts, id);
 291     if (ctype_isref(ct->info)) {
 292       p = *(void **)p;
 293       ct = ctype_rawchild(cts, ct);
 294     }
 295     if (ctype_iscomplex(ct->info)) {
 296       setstrV(L, L->top-1, lj_ctype_repr_complex(L, cdataptr(cd), ct->size));
 297       goto checkgc;
 298     } else if (ct->size == 8 && ctype_isinteger(ct->info)) {
 299       setstrV(L, L->top-1, lj_ctype_repr_int64(L, *(uint64_t *)cdataptr(cd),
 300                                                (ct->info & CTF_UNSIGNED)));
 301       goto checkgc;
 302     } else if (ctype_isfunc(ct->info)) {
 303       p = *(void **)p;
 304     } else if (ctype_isenum(ct->info)) {
 305       msg = "cdata<%s>: %d";
 306       p = (void *)(uintptr_t)*(uint32_t **)p;
 307     } else {
 308       if (ctype_isptr(ct->info)) {
 309         p = cdata_getptr(p, ct->size);
 310         ct = ctype_rawchild(cts, ct);
 311       }
 312       if (ctype_isstruct(ct->info) || ctype_isvector(ct->info)) {
 313         /* Handle ctype __tostring metamethod. */
 314         cTValue *tv = lj_ctype_meta(cts, ctype_typeid(cts, ct), MM_tostring);
 315         if (tv)
 316           return lj_meta_tailcall(L, tv);
 317       }
 318     }
 319   }
 320   lj_str_pushf(L, msg, strdata(lj_ctype_repr(L, id, NULL)), p);
 321 checkgc:
 322   lj_gc_check(L);
 323   return 1;
 324 }
 325
 326 LJLIB_PUSH("ffi") LJLIB_SET(__metatable)
 327
 328 #include "lj_libdef.h"
 329
 330 /* -- C library metamethods ----------------------------------------------- */
 331
 332 #define LJLIB_MODULE_ffi_clib
 333
 334 /* Index C library by a name. */
 335 static TValue *ffi_clib_index(lua_State *L)
 336 {
 337   TValue *o = L->base;
 338   CLibrary *cl;
 339   if (!(o < L->top && tvisudata(o) && udataV(o)->udtype == UDTYPE_FFI_CLIB))
 340     lj_err_argt(L, 1, LUA_TUSERDATA);
 341   cl = (CLibrary *)uddata(udataV(o));
 342   if (!(o+1 < L->top && tvisstr(o+1)))
 343     lj_err_argt(L, 2, LUA_TSTRING);
 344   return lj_clib_index(L, cl, strV(o+1));
 345 }
 346
 347 LJLIB_CF(ffi_clib___index)      LJLIB_REC(clib_index 1)
 348 {
 349   TValue *tv = ffi_clib_index(L);
 350   if (tviscdata(tv)) {
 351     CTState *cts = ctype_cts(L);
 352     GCcdata *cd = cdataV(tv);
 353     CType *s = ctype_get(cts, cd->ctypeid);
 354     if (ctype_isextern(s->info)) {
 355       CTypeID sid = ctype_cid(s->info);
 356       void *sp = *(void **)cdataptr(cd);
 357       CType *ct = ctype_raw(cts, sid);
 358       if (lj_cconv_tv_ct(cts, ct, sid, L->top-1, sp))
 359         lj_gc_check(L);
 360       return 1;
 361     }
 362   }
 363   copyTV(L, L->top-1, tv);
 364   return 1;
 365 }
 366
 367 LJLIB_CF(ffi_clib___newindex)   LJLIB_REC(clib_index 0)
 368 {
 369   TValue *tv = ffi_clib_index(L);
 370   TValue *o = L->base+2;
 371   if (o < L->top && tviscdata(tv)) {
 372     CTState *cts = ctype_cts(L);
 373     GCcdata *cd = cdataV(tv);
 374     CType *d = ctype_get(cts, cd->ctypeid);
 375     if (ctype_isextern(d->info)) {
 376       CTInfo qual = 0;
 377       for (;;) {  /* Skip attributes and collect qualifiers. */
 378         d = ctype_child(cts, d);
 379         if (!ctype_isattrib(d->info)) break;
 380         if (ctype_attrib(d->info) == CTA_QUAL) qual |= d->size;
 381       }
 382       if (!((d->info|qual) & CTF_CONST)) {
 383         lj_cconv_ct_tv(cts, d, *(void **)cdataptr(cd), o, 0);
 384         return 0;
 385       }
 386     }
 387   }
 388   lj_err_caller(L, LJ_ERR_FFI_WRCONST);
 389   return 0;  /* unreachable */
 390 }
 391
 392 LJLIB_CF(ffi_clib___gc)
 393 {
 394   TValue *o = L->base;
 395   if (o < L->top && tvisudata(o) && udataV(o)->udtype == UDTYPE_FFI_CLIB)
 396     lj_clib_unload((CLibrary *)uddata(udataV(o)));
 397   return 0;
 398 }
 399
 400 #include "lj_libdef.h"
 401
 402 /* -- Callback function metamethods --------------------------------------- */
 403
 404 #define LJLIB_MODULE_ffi_callback
 405
 406 static int ffi_callback_set(lua_State *L, GCfunc *fn)
 407 {
 408   GCcdata *cd = ffi_checkcdata(L, 1);
 409   CTState *cts = ctype_cts(L);
 410   CType *ct = ctype_raw(cts, cd->ctypeid);
 411   if (ctype_isptr(ct->info) && (LJ_32 || ct->size == 8)) {
 412     MSize slot = lj_ccallback_ptr2slot(cts, *(void **)cdataptr(cd));
 413     if (slot < cts->cb.sizeid && cts->cb.cbid[slot] != 0) {
 414       GCtab *t = cts->miscmap;
 415       TValue *tv = lj_tab_setint(L, t, (int32_t)slot);
 416       if (fn) {
 417         setfuncV(L, tv, fn);
 418         lj_gc_anybarriert(L, t);
 419       } else {
 420         setnilV(tv);
 421         cts->cb.cbid[slot] = 0;
 422         cts->cb.topid = slot < cts->cb.topid ? slot : cts->cb.topid;
 423       }
 424       return 0;
 425     }
 426   }
 427   lj_err_caller(L, LJ_ERR_FFI_BADCBACK);
 428   return 0;
 429 }
 430
 431 LJLIB_CF(ffi_callback_free)
 432 {
 433   return ffi_callback_set(L, NULL);
 434 }
 435
 436 LJLIB_CF(ffi_callback_set)
 437 {
 438   GCfunc *fn = lj_lib_checkfunc(L, 2);
 439   return ffi_callback_set(L, fn);
 440 }
 441
 442 LJLIB_PUSH(top-1) LJLIB_SET(__index)
 443
 444 #include "lj_libdef.h"
 445
 446 /* -- FFI library functions ----------------------------------------------- */
 447
 448 #define LJLIB_MODULE_ffi
 449
 450 LJLIB_CF(ffi_cdef)
 451 {
 452   GCstr *s = lj_lib_checkstr(L, 1);
 453   CPState cp;
 454   int errcode;
 455   cp.L = L;
 456   cp.cts = ctype_cts(L);
 457   cp.srcname = strdata(s);
 458   cp.p = strdata(s);
 459   cp.param = L->base+1;
 460   cp.mode = CPARSE_MODE_MULTI|CPARSE_MODE_DIRECT;
 461   errcode = lj_cparse(&cp);
 462   if (errcode) lj_err_throw(L, errcode);  /* Propagate errors. */
 463   lj_gc_check(L);
 464   return 0;
 465 }
 466
 467 LJLIB_CF(ffi_new)       LJLIB_REC(.)
 468 {
 469   CTState *cts = ctype_cts(L);
 470   CTypeID id = ffi_checkctype(L, cts, NULL);
 471   CType *ct = ctype_raw(cts, id);
 472   CTSize sz;
 473   CTInfo info = lj_ctype_info(cts, id, &sz);
 474   TValue *o = L->base+1;
 475   GCcdata *cd;
 476   if ((info & CTF_VLA)) {
 477     o++;
 478     sz = lj_ctype_vlsize(cts, ct, (CTSize)ffi_checkint(L, 2));
 479   }
 480   if (sz == CTSIZE_INVALID)
 481     lj_err_arg(L, 1, LJ_ERR_FFI_INVSIZE);
 482   if (!(info & CTF_VLA) && ctype_align(info) <= CT_MEMALIGN)
 483     cd = lj_cdata_new(cts, id, sz);
 484   else
 485     cd = lj_cdata_newv(cts, id, sz, ctype_align(info));
 486   setcdataV(L, o-1, cd);  /* Anchor the uninitialized cdata. */
 487   lj_cconv_ct_init(cts, ct, sz, cdataptr(cd),
 488                    o, (MSize)(L->top - o));  /* Initialize cdata. */
 489   if (ctype_isstruct(ct->info)) {
 490     /* Handle ctype __gc metamethod. Use the fast lookup here. */
 491     cTValue *tv = lj_tab_getinth(cts->miscmap, -(int32_t)id);
 492     if (tv && tvistab(tv) && (tv = lj_meta_fast(L, tabV(tv), MM_gc))) {
 493       GCtab *t = cts->finalizer;
 494       if (gcref(t->metatable)) {
 495         /* Add to finalizer table, if still enabled. */
 496         copyTV(L, lj_tab_set(L, t, o-1), tv);
 497         lj_gc_anybarriert(L, t);
 498         cd->marked |= LJ_GC_CDATA_FIN;
 499       }
 500     }
 501   }
 502   L->top = o;  /* Only return the cdata itself. */
 503   lj_gc_check(L);
 504   return 1;
 505 }
 506
 507 LJLIB_CF(ffi_cast)      LJLIB_REC(ffi_new)
 508 {
 509   CTState *cts = ctype_cts(L);
 510   CTypeID id = ffi_checkctype(L, cts, NULL);
 511   CType *d = ctype_raw(cts, id);
 512   TValue *o = lj_lib_checkany(L, 2);
 513   L->top = o+1;  /* Make sure this is the last item on the stack. */
 514   if (!(ctype_isnum(d->info) || ctype_isptr(d->info) || ctype_isenum(d->info)))
 515     lj_err_arg(L, 1, LJ_ERR_FFI_INVTYPE);
 516   if (!(tviscdata(o) && cdataV(o)->ctypeid == id)) {
 517     GCcdata *cd = lj_cdata_new(cts, id, d->size);
 518     lj_cconv_ct_tv(cts, d, cdataptr(cd), o, CCF_CAST);
 519     setcdataV(L, o, cd);
 520     lj_gc_check(L);
 521   }
 522   return 1;
 523 }
 524
 525 LJLIB_CF(ffi_typeof)    LJLIB_REC(.)
 526 {
 527   CTState *cts = ctype_cts(L);
 528   CTypeID id = ffi_checkctype(L, cts, L->base+1);
 529   GCcdata *cd = lj_cdata_new(cts, CTID_CTYPEID, 4);
 530   *(CTypeID *)cdataptr(cd) = id;
 531   setcdataV(L, L->top-1, cd);
 532   lj_gc_check(L);
 533   return 1;
 534 }
 535
 536 LJLIB_CF(ffi_istype)    LJLIB_REC(.)
 537 {
 538   CTState *cts = ctype_cts(L);
 539   CTypeID id1 = ffi_checkctype(L, cts, NULL);
 540   TValue *o = lj_lib_checkany(L, 2);
 541   int b = 0;
 542   if (tviscdata(o)) {
 543     GCcdata *cd = cdataV(o);
 544     CTypeID id2 = cd->ctypeid == CTID_CTYPEID ? *(CTypeID *)cdataptr(cd) :
 545                                                 cd->ctypeid;
 546     CType *ct1 = lj_ctype_rawref(cts, id1);
 547     CType *ct2 = lj_ctype_rawref(cts, id2);
 548     if (ct1 == ct2) {
 549       b = 1;
 550     } else if (ctype_type(ct1->info) == ctype_type(ct2->info) &&
 551                ct1->size == ct2->size) {
 552       if (ctype_ispointer(ct1->info))
 553         b = lj_cconv_compatptr(cts, ct1, ct2, CCF_IGNQUAL);
 554       else if (ctype_isnum(ct1->info) || ctype_isvoid(ct1->info))
 555         b = (((ct1->info ^ ct2->info) & ~CTF_QUAL) == 0);
 556     } else if (ctype_isstruct(ct1->info) && ctype_isptr(ct2->info) &&
 557                ct1 == ctype_rawchild(cts, ct2)) {
 558       b = 1;
 559     }
 560   }
 561   setboolV(L->top-1, b);
 562   setboolV(&G(L)->tmptv2, b);  /* Remember for trace recorder. */
 563   return 1;
 564 }
 565
 566 LJLIB_CF(ffi_sizeof)
 567 {
 568   CTState *cts = ctype_cts(L);
 569   CTypeID id = ffi_checkctype(L, cts, NULL);
 570   CTSize sz;
 571   if (LJ_UNLIKELY(tviscdata(L->base) && cdataisv(cdataV(L->base)))) {
 572     sz = cdatavlen(cdataV(L->base));
 573   } else {
 574     CType *ct = lj_ctype_rawref(cts, id);
 575     if (ctype_isvltype(ct->info))
 576       sz = lj_ctype_vlsize(cts, ct, (CTSize)ffi_checkint(L, 2));
 577     else
 578       sz = ctype_hassize(ct->info) ? ct->size : CTSIZE_INVALID;
 579     if (LJ_UNLIKELY(sz == CTSIZE_INVALID)) {
 580       setnilV(L->top-1);
 581       return 1;
 582     }
 583   }
 584   setintV(L->top-1, (int32_t)sz);
 585   return 1;
 586 }
 587
 588 LJLIB_CF(ffi_alignof)
 589 {
 590   CTState *cts = ctype_cts(L);
 591   CTypeID id = ffi_checkctype(L, cts, NULL);
 592   CTSize sz = 0;
 593   CTInfo info = lj_ctype_info(cts, id, &sz);
 594   setintV(L->top-1, 1 << ctype_align(info));
 595   return 1;
 596 }
 597
 598 LJLIB_CF(ffi_offsetof)
 599 {
 600   CTState *cts = ctype_cts(L);
 601   CTypeID id = ffi_checkctype(L, cts, NULL);
 602   GCstr *name = lj_lib_checkstr(L, 2);
 603   CType *ct = lj_ctype_rawref(cts, id);
 604   CTSize ofs;
 605   if (ctype_isstruct(ct->info) && ct->size != CTSIZE_INVALID) {
 606     CType *fct = lj_ctype_getfield(cts, ct, name, &ofs);
 607     if (fct) {
 608       setintV(L->top-1, ofs);
 609       if (ctype_isfield(fct->info)) {
 610         return 1;
 611       } else if (ctype_isbitfield(fct->info)) {
 612         setintV(L->top++, ctype_bitpos(fct->info));
 613         setintV(L->top++, ctype_bitbsz(fct->info));
 614         return 3;
 615       }
 616     }
 617   }
 618   return 0;
 619 }
 620
 621 LJLIB_CF(ffi_errno)     LJLIB_REC(.)
 622 {
 623   int err = errno;
 624   if (L->top > L->base)
 625     errno = ffi_checkint(L, 1);
 626   setintV(L->top++, err);
 627   return 1;
 628 }
 629
 630 LJLIB_CF(ffi_string)    LJLIB_REC(.)
 631 {
 632   CTState *cts = ctype_cts(L);
 633   TValue *o = lj_lib_checkany(L, 1);
 634   const char *p;
 635   size_t len;
 636   if (o+1 < L->top) {
 637     len = (size_t)ffi_checkint(L, 2);
 638     lj_cconv_ct_tv(cts, ctype_get(cts, CTID_P_CVOID), (uint8_t *)&p, o,
 639                    CCF_ARG(1));
 640   } else {
 641     lj_cconv_ct_tv(cts, ctype_get(cts, CTID_P_CCHAR), (uint8_t *)&p, o,
 642                    CCF_ARG(1));
 643     len = strlen(p);
 644   }
 645   L->top = o+1;  /* Make sure this is the last item on the stack. */
 646   setstrV(L, o, lj_str_new(L, p, len));
 647   lj_gc_check(L);
 648   return 1;
 649 }
 650
 651 LJLIB_CF(ffi_copy)      LJLIB_REC(.)
 652 {
 653   void *dp = ffi_checkptr(L, 1, CTID_P_VOID);
 654   void *sp = ffi_checkptr(L, 2, CTID_P_CVOID);
 655   TValue *o = L->base+1;
 656   CTSize len;
 657   if (tvisstr(o) && o+1 >= L->top)
 658     len = strV(o)->len+1;  /* Copy Lua string including trailing '\0'. */
 659   else
 660     len = (CTSize)ffi_checkint(L, 3);
 661   memcpy(dp, sp, len);
 662   return 0;
 663 }
 664
 665 LJLIB_CF(ffi_fill)      LJLIB_REC(.)
 666 {
 667   void *dp = ffi_checkptr(L, 1, CTID_P_VOID);
 668   CTSize len = (CTSize)ffi_checkint(L, 2);
 669   int32_t fill = 0;
 670   if (L->base+2 < L->top && !tvisnil(L->base+2)) fill = ffi_checkint(L, 3);
 671   memset(dp, fill, len);
 672   return 0;
 673 }
 674
 675 #define H_(le, be)      LJ_ENDIAN_SELECT(0x##le, 0x##be)
 676
 677 /* Test ABI string. */
 678 LJLIB_CF(ffi_abi)       LJLIB_REC(.)
 679 {
 680   GCstr *s = lj_lib_checkstr(L, 1);
 681   int b = 0;
 682   switch (s->hash) {
 683 #if LJ_64
 684   case H_(849858eb,ad35fd06): b = 1; break;  /* 64bit */
 685 #else
 686   case H_(662d3c79,d0e22477): b = 1; break;  /* 32bit */
 687 #endif
 688 #if LJ_ARCH_HASFPU
 689   case H_(e33ee463,e33ee463): b = 1; break;  /* fpu */
 690 #endif
 691 #if LJ_ABI_SOFTFP
 692   case H_(61211a23,c2e8c81c): b = 1; break;  /* softfp */
 693 #else
 694   case H_(539417a8,8ce0812f): b = 1; break;  /* hardfp */
 695 #endif
 696 #if LJ_ABI_EABI
 697   case H_(2182df8f,f2ed1152): b = 1; break;  /* eabi */
 698 #endif
 699 #if LJ_ABI_WIN
 700   case H_(4ab624a8,4ab624a8): b = 1; break;  /* win */
 701 #endif
 702   case H_(3af93066,1f001464): b = 1; break;  /* le/be */
 703   default:
 704     break;
 705   }
 706   setboolV(L->top-1, b);
 707   setboolV(&G(L)->tmptv2, b);  /* Remember for trace recorder. */
 708   return 1;
 709 }
 710
 711 #undef H_
 712
 713 LJLIB_PUSH(top-8) LJLIB_SET(!)  /* Store reference to miscmap table. */
 714
 715 LJLIB_CF(ffi_metatype)
 716 {
 717   CTState *cts = ctype_cts(L);
 718   CTypeID id = ffi_checkctype(L, cts, NULL);
 719   GCtab *mt = lj_lib_checktab(L, 2);
 720   GCtab *t = cts->miscmap;
 721   CType *ct = ctype_get(cts, id);  /* Only allow raw types. */
 722   TValue *tv;
 723   GCcdata *cd;
 724   if (!(ctype_isstruct(ct->info) || ctype_iscomplex(ct->info) ||
 725         ctype_isvector(ct->info)))
 726     lj_err_arg(L, 1, LJ_ERR_FFI_INVTYPE);
 727   tv = lj_tab_setinth(L, t, -(int32_t)id);
 728   if (!tvisnil(tv))
 729     lj_err_caller(L, LJ_ERR_PROTMT);
 730   settabV(L, tv, mt);
 731   lj_gc_anybarriert(L, t);
 732   cd = lj_cdata_new(cts, CTID_CTYPEID, 4);
 733   *(CTypeID *)cdataptr(cd) = id;
 734   setcdataV(L, L->top-1, cd);
 735   lj_gc_check(L);
 736   return 1;
 737 }
 738
 739 LJLIB_PUSH(top-7) LJLIB_SET(!)  /* Store reference to finalizer table. */
 740
 741 LJLIB_CF(ffi_gc)
 742 {
 743   GCcdata *cd = ffi_checkcdata(L, 1);
 744   TValue *fin = lj_lib_checkany(L, 2);
 745   CTState *cts = ctype_cts(L);
 746   GCtab *t = cts->finalizer;
 747   CType *ct = ctype_raw(cts, cd->ctypeid);
 748   if (!(ctype_isptr(ct->info) || ctype_isstruct(ct->info) ||
 749         ctype_isrefarray(ct->info)))
 750     lj_err_arg(L, 1, LJ_ERR_FFI_INVTYPE);
 751   if (gcref(t->metatable)) {  /* Update finalizer table, if still enabled. */
 752     copyTV(L, lj_tab_set(L, t, L->base), fin);
 753     lj_gc_anybarriert(L, t);
 754     if (!tvisnil(fin))
 755       cd->marked |= LJ_GC_CDATA_FIN;
 756     else
 757       cd->marked &= ~LJ_GC_CDATA_FIN;
 758   }
 759   L->top = L->base+1;  /* Pass through the cdata object. */
 760   return 1;
 761 }
 762
 763 LJLIB_PUSH(top-5) LJLIB_SET(!)  /* Store clib metatable in func environment. */
 764
 765 LJLIB_CF(ffi_load)
 766 {
 767   GCstr *name = lj_lib_checkstr(L, 1);
 768   int global = (L->base+1 < L->top && tvistruecond(L->base+1));
 769   lj_clib_load(L, tabref(curr_func(L)->c.env), name, global);
 770   return 1;
 771 }
 772
 773 LJLIB_PUSH(top-4) LJLIB_SET(C)
 774 LJLIB_PUSH(top-3) LJLIB_SET(os)
 775 LJLIB_PUSH(top-2) LJLIB_SET(arch)
 776
 777 #include "lj_libdef.h"
 778
 779 /* ------------------------------------------------------------------------ */
 780
 781 /* Create special weak-keyed finalizer table. */
 782 static GCtab *ffi_finalizer(lua_State *L)
 783 {
 784   /* NOBARRIER: The table is new (marked white). */
 785   GCtab *t = lj_tab_new(L, 0, 1);
 786   settabV(L, L->top++, t);
 787   setgcref(t->metatable, obj2gco(t));
 788   setstrV(L, lj_tab_setstr(L, t, lj_str_newlit(L, "__mode")),
 789           lj_str_newlit(L, "K"));
 790   t->nomm = (uint8_t)(~(1u<<MM_mode));
 791   return t;
 792 }
 793
 794 /* Register FFI module as loaded. */
 795 static void ffi_register_module(lua_State *L)
 796 {
 797   cTValue *tmp = lj_tab_getstr(tabV(registry(L)), lj_str_newlit(L, "_LOADED"));
 798   if (tmp && tvistab(tmp)) {
 799     GCtab *t = tabV(tmp);
 800     copyTV(L, lj_tab_setstr(L, t, lj_str_newlit(L, LUA_FFILIBNAME)), L->top-1);
 801     lj_gc_anybarriert(L, t);
 802   }
 803 }
 804
 805 LUALIB_API int luaopen_ffi(lua_State *L)
 806 {
 807   CTState *cts = lj_ctype_init(L);
 808   settabV(L, L->top++, (cts->miscmap = lj_tab_new(L, 0, 1)));
 809   cts->finalizer = ffi_finalizer(L);
 810   LJ_LIB_REG(L, NULL, ffi_meta);
 811   /* NOBARRIER: basemt is a GC root. */
 812   setgcref(basemt_it(G(L), LJ_TCDATA), obj2gco(tabV(L->top-1)));
 813   LJ_LIB_REG(L, NULL, ffi_clib);
 814   LJ_LIB_REG(L, NULL, ffi_callback);
 815   /* NOBARRIER: the key is new and lj_tab_newkey() handles the barrier. */
 816   settabV(L, lj_tab_setstr(L, cts->miscmap, &cts->g->strempty), tabV(L->top-1));
 817   L->top--;
 818   lj_clib_default(L, tabV(L->top-1));  /* Create ffi.C default namespace. */
 819   lua_pushliteral(L, LJ_OS_NAME);
 820   lua_pushliteral(L, LJ_ARCH_NAME);
 821   LJ_LIB_REG(L, NULL, ffi);  /* Note: no global "ffi" created! */
 822   ffi_register_module(L);
 823   return 1;
 824 }
 825
 826 #endif