1 /* $NetBSD: lstate.c,v 1.12 2023/06/08 21:12:08 nikita Exp $ */ 2 3 /* 4 ** Id: lstate.c 5 ** Global State 6 ** See Copyright Notice in lua.h 7 */ 8 9 #define lstate_c 10 #define LUA_CORE 11 12 #include "lprefix.h" 13 14 15 #ifndef _KERNEL 16 #include <stddef.h> 17 #include <string.h> 18 #endif /* _KERNEL */ 19 20 #include "lua.h" 21 22 #include "lapi.h" 23 #include "ldebug.h" 24 #include "ldo.h" 25 #include "lfunc.h" 26 #include "lgc.h" 27 #include "llex.h" 28 #include "lmem.h" 29 #include "lstate.h" 30 #include "lstring.h" 31 #include "ltable.h" 32 #include "ltm.h" 33 34 35 36 /* 37 ** thread state + extra space 38 */ 39 typedef struct LX { 40 lu_byte extra_[LUA_EXTRASPACE]; 41 lua_State l; 42 } LX; 43 44 45 /* 46 ** Main thread combines a thread state and the global state 47 */ 48 typedef struct LG { 49 LX l; 50 global_State g; 51 } LG; 52 53 54 55 #define fromstate(L) (cast(LX *, cast(lu_byte *, (L)) - offsetof(LX, l))) 56 57 58 /* 59 ** A macro to create a "random" seed when a state is created; 60 ** the seed is used to randomize string hashes. 61 */ 62 #if !defined(luai_makeseed) 63 64 #include <time.h> 65 66 /* 67 ** Compute an initial seed with some level of randomness. 68 ** Rely on Address Space Layout Randomization (if present) and 69 ** current time. 70 */ 71 #define addbuff(b,p,e) \ 72 { size_t t = cast_sizet(e); \ 73 memcpy(b + p, &t, sizeof(t)); p += sizeof(t); } 74 75 static unsigned int luai_makeseed (lua_State *L) { 76 char buff[3 * sizeof(size_t)]; 77 unsigned int h = cast_uint(time(NULL)); 78 int p = 0; 79 addbuff(buff, p, L); /* heap variable */ 80 addbuff(buff, p, &h); /* local variable */ 81 addbuff(buff, p, &lua_newstate); /* public function */ 82 lua_assert(p == sizeof(buff)); 83 return luaS_hash(buff, p, h); 84 } 85 86 #endif 87 88 89 /* 90 ** set GCdebt to a new value keeping the value (totalbytes + GCdebt) 91 ** invariant (and avoiding underflows in 'totalbytes') 92 */ 93 void luaE_setdebt (global_State *g, l_mem debt) { 94 l_mem tb = gettotalbytes(g); 95 lua_assert(tb > 0); 96 if (debt < tb - MAX_LMEM) 97 debt = tb - MAX_LMEM; /* will make 'totalbytes == MAX_LMEM' */ 98 g->totalbytes = tb - debt; 99 g->GCdebt = debt; 100 } 101 102 103 LUA_API int lua_setcstacklimit (lua_State *L, unsigned int limit) { 104 UNUSED(L); UNUSED(limit); 105 return LUAI_MAXCCALLS; /* warning?? */ 106 } 107 108 109 CallInfo *luaE_extendCI (lua_State *L) { 110 CallInfo *ci; 111 lua_assert(L->ci->next == NULL); 112 ci = luaM_new(L, CallInfo); 113 lua_assert(L->ci->next == NULL); 114 L->ci->next = ci; 115 ci->previous = L->ci; 116 ci->next = NULL; 117 ci->u.l.trap = 0; 118 L->nci++; 119 return ci; 120 } 121 122 123 /* 124 ** free all CallInfo structures not in use by a thread 125 */ 126 void luaE_freeCI (lua_State *L) { 127 CallInfo *ci = L->ci; 128 CallInfo *next = ci->next; 129 ci->next = NULL; 130 while ((ci = next) != NULL) { 131 next = ci->next; 132 luaM_free(L, ci); 133 L->nci--; 134 } 135 } 136 137 138 /* 139 ** free half of the CallInfo structures not in use by a thread, 140 ** keeping the first one. 141 */ 142 void luaE_shrinkCI (lua_State *L) { 143 CallInfo *ci = L->ci->next; /* first free CallInfo */ 144 CallInfo *next; 145 if (ci == NULL) 146 return; /* no extra elements */ 147 while ((next = ci->next) != NULL) { /* two extra elements? */ 148 CallInfo *next2 = next->next; /* next's next */ 149 ci->next = next2; /* remove next from the list */ 150 L->nci--; 151 luaM_free(L, next); /* free next */ 152 if (next2 == NULL) 153 break; /* no more elements */ 154 else { 155 next2->previous = ci; 156 ci = next2; /* continue */ 157 } 158 } 159 } 160 161 162 /* 163 ** Called when 'getCcalls(L)' larger or equal to LUAI_MAXCCALLS. 164 ** If equal, raises an overflow error. If value is larger than 165 ** LUAI_MAXCCALLS (which means it is handling an overflow) but 166 ** not much larger, does not report an error (to allow overflow 167 ** handling to work). 168 */ 169 void luaE_checkcstack (lua_State *L) { 170 if (getCcalls(L) == LUAI_MAXCCALLS) 171 luaG_runerror(L, "C stack overflow"); 172 else if (getCcalls(L) >= (LUAI_MAXCCALLS / 10 * 11)) 173 luaD_throw(L, LUA_ERRERR); /* error while handling stack error */ 174 } 175 176 177 LUAI_FUNC void luaE_incCstack (lua_State *L) { 178 L->nCcalls++; 179 if (l_unlikely(getCcalls(L) >= LUAI_MAXCCALLS)) 180 luaE_checkcstack(L); 181 } 182 183 184 static void stack_init (lua_State *L1, lua_State *L) { 185 int i; CallInfo *ci; 186 /* initialize stack array */ 187 L1->stack.p = luaM_newvector(L, BASIC_STACK_SIZE + EXTRA_STACK, StackValue); 188 L1->tbclist.p = L1->stack.p; 189 for (i = 0; i < BASIC_STACK_SIZE + EXTRA_STACK; i++) 190 setnilvalue(s2v(L1->stack.p + i)); /* erase new stack */ 191 L1->top.p = L1->stack.p; 192 L1->stack_last.p = L1->stack.p + BASIC_STACK_SIZE; 193 /* initialize first ci */ 194 ci = &L1->base_ci; 195 ci->next = ci->previous = NULL; 196 ci->callstatus = CIST_C; 197 ci->func.p = L1->top.p; 198 ci->u.c.k = NULL; 199 ci->nresults = 0; 200 setnilvalue(s2v(L1->top.p)); /* 'function' entry for this 'ci' */ 201 L1->top.p++; 202 ci->top.p = L1->top.p + LUA_MINSTACK; 203 L1->ci = ci; 204 } 205 206 207 static void freestack (lua_State *L) { 208 if (L->stack.p == NULL) 209 return; /* stack not completely built yet */ 210 L->ci = &L->base_ci; /* free the entire 'ci' list */ 211 luaE_freeCI(L); 212 lua_assert(L->nci == 0); 213 luaM_freearray(L, L->stack.p, stacksize(L) + EXTRA_STACK); /* free stack */ 214 } 215 216 217 /* 218 ** Create registry table and its predefined values 219 */ 220 static void init_registry (lua_State *L, global_State *g) { 221 /* create registry */ 222 Table *registry = luaH_new(L); 223 sethvalue(L, &g->l_registry, registry); 224 luaH_resize(L, registry, LUA_RIDX_LAST, 0); 225 /* registry[LUA_RIDX_MAINTHREAD] = L */ 226 setthvalue(L, ®istry->array[LUA_RIDX_MAINTHREAD - 1], L); 227 /* registry[LUA_RIDX_GLOBALS] = new table (table of globals) */ 228 sethvalue(L, ®istry->array[LUA_RIDX_GLOBALS - 1], luaH_new(L)); 229 } 230 231 232 /* 233 ** open parts of the state that may cause memory-allocation errors. 234 */ 235 static void f_luaopen (lua_State *L, void *ud) { 236 global_State *g = G(L); 237 UNUSED(ud); 238 stack_init(L, L); /* init stack */ 239 init_registry(L, g); 240 luaS_init(L); 241 luaT_init(L); 242 luaX_init(L); 243 g->gcstp = 0; /* allow gc */ 244 setnilvalue(&g->nilvalue); /* now state is complete */ 245 luai_userstateopen(L); 246 } 247 248 249 /* 250 ** preinitialize a thread with consistent values without allocating 251 ** any memory (to avoid errors) 252 */ 253 static void preinit_thread (lua_State *L, global_State *g) { 254 G(L) = g; 255 L->stack.p = NULL; 256 L->ci = NULL; 257 L->nci = 0; 258 L->twups = L; /* thread has no upvalues */ 259 L->nCcalls = 0; 260 L->errorJmp = NULL; 261 L->hook = NULL; 262 L->hookmask = 0; 263 L->basehookcount = 0; 264 L->allowhook = 1; 265 resethookcount(L); 266 L->openupval = NULL; 267 L->status = LUA_OK; 268 L->errfunc = 0; 269 L->oldpc = 0; 270 } 271 272 273 static void close_state (lua_State *L) { 274 global_State *g = G(L); 275 if (!completestate(g)) /* closing a partially built state? */ 276 luaC_freeallobjects(L); /* just collect its objects */ 277 else { /* closing a fully built state */ 278 L->ci = &L->base_ci; /* unwind CallInfo list */ 279 luaD_closeprotected(L, 1, LUA_OK); /* close all upvalues */ 280 luaC_freeallobjects(L); /* collect all objects */ 281 luai_userstateclose(L); 282 } 283 luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size); 284 freestack(L); 285 lua_assert(gettotalbytes(g) == sizeof(LG)); 286 (*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0); /* free main block */ 287 } 288 289 290 LUA_API lua_State *lua_newthread (lua_State *L) { 291 global_State *g = G(L); 292 GCObject *o; 293 lua_State *L1; 294 lua_lock(L); 295 luaC_checkGC(L); 296 /* create new thread */ 297 o = luaC_newobjdt(L, LUA_TTHREAD, sizeof(LX), offsetof(LX, l)); 298 L1 = gco2th(o); 299 /* anchor it on L stack */ 300 setthvalue2s(L, L->top.p, L1); 301 api_incr_top(L); 302 preinit_thread(L1, g); 303 L1->hookmask = L->hookmask; 304 L1->basehookcount = L->basehookcount; 305 L1->hook = L->hook; 306 resethookcount(L1); 307 /* initialize L1 extra space */ 308 memcpy(lua_getextraspace(L1), lua_getextraspace(g->mainthread), 309 LUA_EXTRASPACE); 310 luai_userstatethread(L, L1); 311 stack_init(L1, L); /* init stack */ 312 lua_unlock(L); 313 return L1; 314 } 315 316 317 void luaE_freethread (lua_State *L, lua_State *L1) { 318 LX *l = fromstate(L1); 319 luaF_closeupval(L1, L1->stack.p); /* close all upvalues */ 320 lua_assert(L1->openupval == NULL); 321 luai_userstatefree(L, L1); 322 freestack(L1); 323 luaM_free(L, l); 324 } 325 326 327 int luaE_resetthread (lua_State *L, int status) { 328 CallInfo *ci = L->ci = &L->base_ci; /* unwind CallInfo list */ 329 setnilvalue(s2v(L->stack.p)); /* 'function' entry for basic 'ci' */ 330 ci->func.p = L->stack.p; 331 ci->callstatus = CIST_C; 332 if (status == LUA_YIELD) 333 status = LUA_OK; 334 L->status = LUA_OK; /* so it can run __close metamethods */ 335 status = luaD_closeprotected(L, 1, status); 336 if (status != LUA_OK) /* errors? */ 337 luaD_seterrorobj(L, status, L->stack.p + 1); 338 else 339 L->top.p = L->stack.p + 1; 340 ci->top.p = L->top.p + LUA_MINSTACK; 341 luaD_reallocstack(L, cast_int(ci->top.p - L->stack.p), 0); 342 return status; 343 } 344 345 346 LUA_API int lua_closethread (lua_State *L, lua_State *from) { 347 int status; 348 lua_lock(L); 349 L->nCcalls = (from) ? getCcalls(from) : 0; 350 status = luaE_resetthread(L, L->status); 351 lua_unlock(L); 352 return status; 353 } 354 355 356 /* 357 ** Deprecated! Use 'lua_closethread' instead. 358 */ 359 LUA_API int lua_resetthread (lua_State *L) { 360 return lua_closethread(L, NULL); 361 } 362 363 364 LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) { 365 int i; 366 lua_State *L; 367 global_State *g; 368 LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG))); 369 if (l == NULL) return NULL; 370 L = &l->l.l; 371 g = &l->g; 372 L->tt = LUA_VTHREAD; 373 g->currentwhite = bitmask(WHITE0BIT); 374 L->marked = luaC_white(g); 375 preinit_thread(L, g); 376 g->allgc = obj2gco(L); /* by now, only object is the main thread */ 377 L->next = NULL; 378 incnny(L); /* main thread is always non yieldable */ 379 g->frealloc = f; 380 g->ud = ud; 381 g->warnf = NULL; 382 g->ud_warn = NULL; 383 g->mainthread = L; 384 g->seed = luai_makeseed(L); 385 g->gcstp = GCSTPGC; /* no GC while building state */ 386 g->strt.size = g->strt.nuse = 0; 387 g->strt.hash = NULL; 388 setnilvalue(&g->l_registry); 389 g->panic = NULL; 390 g->gcstate = GCSpause; 391 g->gckind = KGC_INC; 392 g->gcstopem = 0; 393 g->gcemergency = 0; 394 g->finobj = g->tobefnz = g->fixedgc = NULL; 395 g->firstold1 = g->survival = g->old1 = g->reallyold = NULL; 396 g->finobjsur = g->finobjold1 = g->finobjrold = NULL; 397 g->sweepgc = NULL; 398 g->gray = g->grayagain = NULL; 399 g->weak = g->ephemeron = g->allweak = NULL; 400 g->twups = NULL; 401 g->totalbytes = sizeof(LG); 402 g->GCdebt = 0; 403 g->lastatomic = 0; 404 setivalue(&g->nilvalue, 0); /* to signal that state is not yet built */ 405 setgcparam(g->gcpause, LUAI_GCPAUSE); 406 setgcparam(g->gcstepmul, LUAI_GCMUL); 407 g->gcstepsize = LUAI_GCSTEPSIZE; 408 setgcparam(g->genmajormul, LUAI_GENMAJORMUL); 409 g->genminormul = LUAI_GENMINORMUL; 410 for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL; 411 if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) { 412 /* memory allocation error: free partial state */ 413 close_state(L); 414 L = NULL; 415 } 416 return L; 417 } 418 419 420 LUA_API void lua_close (lua_State *L) { 421 lua_lock(L); 422 L = G(L)->mainthread; /* only the main thread can be closed */ 423 close_state(L); 424 } 425 426 427 void luaE_warning (lua_State *L, const char *msg, int tocont) { 428 lua_WarnFunction wf = G(L)->warnf; 429 if (wf != NULL) 430 wf(G(L)->ud_warn, msg, tocont); 431 } 432 433 434 /* 435 ** Generate a warning from an error message 436 */ 437 void luaE_warnerror (lua_State *L, const char *where) { 438 TValue *errobj = s2v(L->top.p - 1); /* error object */ 439 const char *msg = (ttisstring(errobj)) 440 ? svalue(errobj) 441 : "error object is not a string"; 442 /* produce warning "error in %s (%s)" (where, msg) */ 443 luaE_warning(L, "error in ", 1); 444 luaE_warning(L, where, 1); 445 luaE_warning(L, " (", 1); 446 luaE_warning(L, msg, 1); 447 luaE_warning(L, ")", 0); 448 } 449 450
Indexes created Tue Feb 24 08:35:24 UTC 2026