1 /* $NetBSD: lstate.c,v 1.9 2018/08/04 17:30:01 alnsn Exp $ */ 2 3 /* 4 ** Id: lstate.c,v 2.133.1.1 2017/04/19 17:39:34 roberto Exp 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 #if !defined(LUAI_GCPAUSE) 36 #define LUAI_GCPAUSE 200 /* 200% */ 37 #endif 38 39 #if !defined(LUAI_GCMUL) 40 #define LUAI_GCMUL 200 /* GC runs 'twice the speed' of memory allocation */ 41 #endif 42 43 44 /* 45 ** a macro to help the creation of a unique random seed when a state is 46 ** created; the seed is used to randomize hashes. 47 */ 48 #if !defined(luai_makeseed) 49 #include <time.h> 50 #define luai_makeseed() cast(unsigned int, time(NULL)) 51 #endif 52 53 54 55 /* 56 ** thread state + extra space 57 */ 58 typedef struct LX { 59 lu_byte extra_[LUA_EXTRASPACE]; 60 lua_State l; 61 } LX; 62 63 64 /* 65 ** Main thread combines a thread state and the global state 66 */ 67 typedef struct LG { 68 LX l; 69 global_State g; 70 } LG; 71 72 73 74 #define fromstate(L) (cast(LX *, cast(lu_byte *, (L)) - offsetof(LX, l))) 75 76 77 /* 78 ** Compute an initial seed as random as possible. Rely on Address Space 79 ** Layout Randomization (if present) to increase randomness.. 80 */ 81 #define addbuff(b,p,e) \ 82 { size_t t = cast(size_t, e); \ 83 memcpy(b + p, &t, sizeof(t)); p += sizeof(t); } 84 85 static unsigned int makeseed (lua_State *L) { 86 char buff[4 * sizeof(size_t)]; 87 unsigned int h = luai_makeseed(); 88 int p = 0; 89 addbuff(buff, p, L); /* heap variable */ 90 addbuff(buff, p, &h); /* local variable */ 91 addbuff(buff, p, luaO_nilobject); /* global variable */ 92 addbuff(buff, p, &lua_newstate); /* public function */ 93 lua_assert(p == sizeof(buff)); 94 return luaS_hash(buff, p, h); 95 } 96 97 98 /* 99 ** set GCdebt to a new value keeping the value (totalbytes + GCdebt) 100 ** invariant (and avoiding underflows in 'totalbytes') 101 */ 102 void luaE_setdebt (global_State *g, l_mem debt) { 103 l_mem tb = gettotalbytes(g); 104 lua_assert(tb > 0); 105 if (debt < tb - MAX_LMEM) 106 debt = tb - MAX_LMEM; /* will make 'totalbytes == MAX_LMEM' */ 107 g->totalbytes = tb - debt; 108 g->GCdebt = debt; 109 } 110 111 112 CallInfo *luaE_extendCI (lua_State *L) { 113 CallInfo *ci = luaM_new(L, CallInfo); 114 lua_assert(L->ci->next == NULL); 115 L->ci->next = ci; 116 ci->previous = L->ci; 117 ci->next = NULL; 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 */ 141 void luaE_shrinkCI (lua_State *L) { 142 CallInfo *ci = L->ci; 143 CallInfo *next2; /* next's next */ 144 /* while there are two nexts */ 145 while (ci->next != NULL && (next2 = ci->next->next) != NULL) { 146 luaM_free(L, ci->next); /* free next */ 147 L->nci--; 148 ci->next = next2; /* remove 'next' from the list */ 149 next2->previous = ci; 150 ci = next2; /* keep next's next */ 151 } 152 } 153 154 155 static void stack_init (lua_State *L1, lua_State *L) { 156 int i; CallInfo *ci; 157 /* initialize stack array */ 158 L1->stack = luaM_newvector(L, BASIC_STACK_SIZE, TValue); 159 L1->stacksize = BASIC_STACK_SIZE; 160 for (i = 0; i < BASIC_STACK_SIZE; i++) 161 setnilvalue(L1->stack + i); /* erase new stack */ 162 L1->top = L1->stack; 163 L1->stack_last = L1->stack + L1->stacksize - EXTRA_STACK; 164 /* initialize first ci */ 165 ci = &L1->base_ci; 166 ci->next = ci->previous = NULL; 167 ci->callstatus = 0; 168 ci->func = L1->top; 169 setnilvalue(L1->top++); /* 'function' entry for this 'ci' */ 170 ci->top = L1->top + LUA_MINSTACK; 171 L1->ci = ci; 172 } 173 174 175 static void freestack (lua_State *L) { 176 if (L->stack == NULL) 177 return; /* stack not completely built yet */ 178 L->ci = &L->base_ci; /* free the entire 'ci' list */ 179 luaE_freeCI(L); 180 lua_assert(L->nci == 0); 181 luaM_freearray(L, L->stack, L->stacksize); /* free stack array */ 182 } 183 184 185 /* 186 ** Create registry table and its predefined values 187 */ 188 static void init_registry (lua_State *L, global_State *g) { 189 TValue temp; 190 /* create registry */ 191 Table *registry = luaH_new(L); 192 sethvalue(L, &g->l_registry, registry); 193 luaH_resize(L, registry, LUA_RIDX_LAST, 0); 194 /* registry[LUA_RIDX_MAINTHREAD] = L */ 195 setthvalue(L, &temp, L); /* temp = L */ 196 luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &temp); 197 /* registry[LUA_RIDX_GLOBALS] = table of globals */ 198 sethvalue(L, &temp, luaH_new(L)); /* temp = new table (global table) */ 199 luaH_setint(L, registry, LUA_RIDX_GLOBALS, &temp); 200 } 201 202 203 /* 204 ** open parts of the state that may cause memory-allocation errors. 205 ** ('g->version' != NULL flags that the state was completely build) 206 */ 207 static void f_luaopen (lua_State *L, void *ud) { 208 global_State *g = G(L); 209 UNUSED(ud); 210 stack_init(L, L); /* init stack */ 211 init_registry(L, g); 212 luaS_init(L); 213 luaT_init(L); 214 luaX_init(L); 215 g->gcrunning = 1; /* allow gc */ 216 g->version = lua_version(NULL); 217 luai_userstateopen(L); 218 } 219 220 221 /* 222 ** preinitialize a thread with consistent values without allocating 223 ** any memory (to avoid errors) 224 */ 225 static void preinit_thread (lua_State *L, global_State *g) { 226 G(L) = g; 227 L->stack = NULL; 228 L->ci = NULL; 229 L->nci = 0; 230 L->stacksize = 0; 231 L->twups = L; /* thread has no upvalues */ 232 L->errorJmp = NULL; 233 L->nCcalls = 0; 234 L->hook = NULL; 235 L->hookmask = 0; 236 L->basehookcount = 0; 237 L->allowhook = 1; 238 resethookcount(L); 239 L->openupval = NULL; 240 L->nny = 1; 241 L->status = LUA_OK; 242 L->errfunc = 0; 243 } 244 245 246 static void close_state (lua_State *L) { 247 global_State *g = G(L); 248 luaF_close(L, L->stack); /* close all upvalues for this thread */ 249 luaC_freeallobjects(L); /* collect all objects */ 250 if (g->version) /* closing a fully built state? */ 251 luai_userstateclose(L); 252 luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size); 253 freestack(L); 254 lua_assert(gettotalbytes(g) == sizeof(LG)); 255 (*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0); /* free main block */ 256 } 257 258 259 LUA_API lua_State *lua_newthread (lua_State *L) { 260 global_State *g = G(L); 261 lua_State *L1; 262 lua_lock(L); 263 luaC_checkGC(L); 264 /* create new thread */ 265 L1 = &cast(LX *, luaM_newobject(L, LUA_TTHREAD, sizeof(LX)))->l; 266 L1->marked = luaC_white(g); 267 L1->tt = LUA_TTHREAD; 268 /* link it on list 'allgc' */ 269 L1->next = g->allgc; 270 g->allgc = obj2gco(L1); 271 /* anchor it on L stack */ 272 setthvalue(L, L->top, L1); 273 api_incr_top(L); 274 preinit_thread(L1, g); 275 L1->hookmask = L->hookmask; 276 L1->basehookcount = L->basehookcount; 277 L1->hook = L->hook; 278 resethookcount(L1); 279 /* initialize L1 extra space */ 280 memcpy(lua_getextraspace(L1), lua_getextraspace(g->mainthread), 281 LUA_EXTRASPACE); 282 luai_userstatethread(L, L1); 283 stack_init(L1, L); /* init stack */ 284 lua_unlock(L); 285 return L1; 286 } 287 288 289 void luaE_freethread (lua_State *L, lua_State *L1) { 290 LX *l = fromstate(L1); 291 luaF_close(L1, L1->stack); /* close all upvalues for this thread */ 292 lua_assert(L1->openupval == NULL); 293 luai_userstatefree(L, L1); 294 freestack(L1); 295 luaM_free(L, l); 296 } 297 298 299 LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) { 300 int i; 301 lua_State *L; 302 global_State *g; 303 LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG))); 304 if (l == NULL) return NULL; 305 L = &l->l.l; 306 g = &l->g; 307 L->next = NULL; 308 L->tt = LUA_TTHREAD; 309 g->currentwhite = bitmask(WHITE0BIT); 310 L->marked = luaC_white(g); 311 preinit_thread(L, g); 312 g->frealloc = f; 313 g->ud = ud; 314 g->mainthread = L; 315 g->seed = makeseed(L); 316 g->gcrunning = 0; /* no GC while building state */ 317 g->GCestimate = 0; 318 g->strt.size = g->strt.nuse = 0; 319 g->strt.hash = NULL; 320 setnilvalue(&g->l_registry); 321 g->panic = NULL; 322 g->version = NULL; 323 g->gcstate = GCSpause; 324 g->gckind = KGC_NORMAL; 325 g->allgc = g->finobj = g->tobefnz = g->fixedgc = NULL; 326 g->sweepgc = NULL; 327 g->gray = g->grayagain = NULL; 328 g->weak = g->ephemeron = g->allweak = NULL; 329 g->twups = NULL; 330 g->totalbytes = sizeof(LG); 331 g->GCdebt = 0; 332 g->gcfinnum = 0; 333 g->gcpause = LUAI_GCPAUSE; 334 g->gcstepmul = LUAI_GCMUL; 335 for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL; 336 if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) { 337 /* memory allocation error: free partial state */ 338 close_state(L); 339 L = NULL; 340 } 341 return L; 342 } 343 344 345 LUA_API void lua_close (lua_State *L) { 346 L = G(L)->mainthread; /* only the main thread can be closed */ 347 lua_lock(L); 348 close_state(L); 349 } 350 351 352