external/mit/lua/dist/src/lstate.c

   1 /*      $NetBSD: lstate.c,v 1.4 2015/10/08 13:21:00 mbalmer Exp $       */
   2
   3 /*
   4 ** Id: lstate.c,v 2.128 2015/03/04 13:31:21 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
  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(buff + 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
 101 */
 102 void luaE_setdebt (global_State *g, l_mem debt) {
 103   g->totalbytes -= (debt - g->GCdebt);
 104   g->GCdebt = debt;
 105 }
 106
 107
 108 CallInfo *luaE_extendCI (lua_State *L) {
 109   CallInfo *ci = luaM_new(L, CallInfo);
 110   lua_assert(L->ci->next == NULL);
 111   L->ci->next = ci;
 112   ci->previous = L->ci;
 113   ci->next = NULL;
 114   return ci;
 115 }
 116
 117
 118 /*
 119 ** free all CallInfo structures not in use by a thread
 120 */
 121 void luaE_freeCI (lua_State *L) {
 122   CallInfo *ci = L->ci;
 123   CallInfo *next = ci->next;
 124   ci->next = NULL;
 125   while ((ci = next) != NULL) {
 126     next = ci->next;
 127     luaM_free(L, ci);
 128   }
 129 }
 130
 131
 132 /*
 133 ** free half of the CallInfo structures not in use by a thread
 134 */
 135 void luaE_shrinkCI (lua_State *L) {
 136   CallInfo *ci = L->ci;
 137   while (ci->next != NULL) {  /* while there is 'next' */
 138     CallInfo *next2 = ci->next->next;  /* next's next */
 139     if (next2 == NULL) break;
 140     luaM_free(L, ci->next);  /* remove next */
 141     ci->next = next2;  /* remove 'next' from the list */
 142     next2->previous = ci;
 143     ci = next2;
 144   }
 145 }
 146
 147
 148 static void stack_init (lua_State *L1, lua_State *L) {
 149   int i; CallInfo *ci;
 150   /* initialize stack array */
 151   L1->stack = luaM_newvector(L, BASIC_STACK_SIZE, TValue);
 152   L1->stacksize = BASIC_STACK_SIZE;
 153   for (i = 0; i < BASIC_STACK_SIZE; i++)
 154     setnilvalue(L1->stack + i);  /* erase new stack */
 155   L1->top = L1->stack;
 156   L1->stack_last = L1->stack + L1->stacksize - EXTRA_STACK;
 157   /* initialize first ci */
 158   ci = &L1->base_ci;
 159   ci->next = ci->previous = NULL;
 160   ci->callstatus = 0;
 161   ci->func = L1->top;
 162   setnilvalue(L1->top++);  /* 'function' entry for this 'ci' */
 163   ci->top = L1->top + LUA_MINSTACK;
 164   L1->ci = ci;
 165 }
 166
 167
 168 static void freestack (lua_State *L) {
 169   if (L->stack == NULL)
 170     return;  /* stack not completely built yet */
 171   L->ci = &L->base_ci;  /* free the entire 'ci' list */
 172   luaE_freeCI(L);
 173   luaM_freearray(L, L->stack, L->stacksize);  /* free stack array */
 174 }
 175
 176
 177 /*
 178 ** Create registry table and its predefined values
 179 */
 180 static void init_registry (lua_State *L, global_State *g) {
 181   TValue temp;
 182   /* create registry */
 183   Table *registry = luaH_new(L);
 184   sethvalue(L, &g->l_registry, registry);
 185   luaH_resize(L, registry, LUA_RIDX_LAST, 0);
 186   /* registry[LUA_RIDX_MAINTHREAD] = L */
 187   setthvalue(L, &temp, L);  /* temp = L */
 188   luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &temp);
 189   /* registry[LUA_RIDX_GLOBALS] = table of globals */
 190   sethvalue(L, &temp, luaH_new(L));  /* temp = new table (global table) */
 191   luaH_setint(L, registry, LUA_RIDX_GLOBALS, &temp);
 192 }
 193
 194
 195 /*
 196 ** open parts of the state that may cause memory-allocation errors.
 197 ** ('g->version' != NULL flags that the state was completely build)
 198 */
 199 static void f_luaopen (lua_State *L, void *ud) {
 200   global_State *g = G(L);
 201   UNUSED(ud);
 202   stack_init(L, L);  /* init stack */
 203   init_registry(L, g);
 204   luaS_init(L);
 205   luaT_init(L);
 206   luaX_init(L);
 207   g->gcrunning = 1;  /* allow gc */
 208   g->version = lua_version(NULL);
 209   luai_userstateopen(L);
 210 }
 211
 212
 213 /*
 214 ** preinitialize a thread with consistent values without allocating
 215 ** any memory (to avoid errors)
 216 */
 217 static void preinit_thread (lua_State *L, global_State *g) {
 218   G(L) = g;
 219   L->stack = NULL;
 220   L->ci = NULL;
 221   L->stacksize = 0;
 222   L->twups = L;  /* thread has no upvalues */
 223   L->errorJmp = NULL;
 224   L->nCcalls = 0;
 225   L->hook = NULL;
 226   L->hookmask = 0;
 227   L->basehookcount = 0;
 228   L->allowhook = 1;
 229   resethookcount(L);
 230   L->openupval = NULL;
 231   L->nny = 1;
 232   L->status = LUA_OK;
 233   L->errfunc = 0;
 234 }
 235
 236
 237 static void close_state (lua_State *L) {
 238   global_State *g = G(L);
 239   luaF_close(L, L->stack);  /* close all upvalues for this thread */
 240   luaC_freeallobjects(L);  /* collect all objects */
 241   if (g->version)  /* closing a fully built state? */
 242     luai_userstateclose(L);
 243   luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size);
 244   luaZ_freebuffer(L, &g->buff);
 245   freestack(L);
 246   lua_assert(gettotalbytes(g) == sizeof(LG));
 247   (*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0);  /* free main block */
 248 }
 249
 250
 251 LUA_API lua_State *lua_newthread (lua_State *L) {
 252   global_State *g = G(L);
 253   lua_State *L1;
 254   lua_lock(L);
 255   luaC_checkGC(L);
 256   /* create new thread */
 257   L1 = &cast(LX *, luaM_newobject(L, LUA_TTHREAD, sizeof(LX)))->l;
 258   L1->marked = luaC_white(g);
 259   L1->tt = LUA_TTHREAD;
 260   /* link it on list 'allgc' */
 261   L1->next = g->allgc;
 262   g->allgc = obj2gco(L1);
 263   /* anchor it on L stack */
 264   setthvalue(L, L->top, L1);
 265   api_incr_top(L);
 266   preinit_thread(L1, g);
 267   L1->hookmask = L->hookmask;
 268   L1->basehookcount = L->basehookcount;
 269   L1->hook = L->hook;
 270   resethookcount(L1);
 271   /* initialize L1 extra space */
 272   memcpy(lua_getextraspace(L1), lua_getextraspace(g->mainthread),
 273          LUA_EXTRASPACE);
 274   luai_userstatethread(L, L1);
 275   stack_init(L1, L);  /* init stack */
 276   lua_unlock(L);
 277   return L1;
 278 }
 279
 280
 281 void luaE_freethread (lua_State *L, lua_State *L1) {
 282   LX *l = fromstate(L1);
 283   luaF_close(L1, L1->stack);  /* close all upvalues for this thread */
 284   lua_assert(L1->openupval == NULL);
 285   luai_userstatefree(L, L1);
 286   freestack(L1);
 287   luaM_free(L, l);
 288 }
 289
 290
 291 LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
 292   int i;
 293   lua_State *L;
 294   global_State *g;
 295   LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG)));
 296   if (l == NULL) return NULL;
 297   L = &l->l.l;
 298   g = &l->g;
 299   L->next = NULL;
 300   L->tt = LUA_TTHREAD;
 301   g->currentwhite = bitmask(WHITE0BIT);
 302   L->marked = luaC_white(g);
 303   preinit_thread(L, g);
 304   g->frealloc = f;
 305   g->ud = ud;
 306   g->mainthread = L;
 307   g->seed = makeseed(L);
 308   g->gcrunning = 0;  /* no GC while building state */
 309   g->GCestimate = 0;
 310   g->strt.size = g->strt.nuse = 0;
 311   g->strt.hash = NULL;
 312   setnilvalue(&g->l_registry);
 313   luaZ_initbuffer(L, &g->buff);
 314   g->panic = NULL;
 315   g->version = NULL;
 316   g->gcstate = GCSpause;
 317   g->gckind = KGC_NORMAL;
 318   g->allgc = g->finobj = g->tobefnz = g->fixedgc = NULL;
 319   g->sweepgc = NULL;
 320   g->gray = g->grayagain = NULL;
 321   g->weak = g->ephemeron = g->allweak = NULL;
 322   g->twups = NULL;
 323   g->totalbytes = sizeof(LG);
 324   g->GCdebt = 0;
 325   g->gcfinnum = 0;
 326   g->gcpause = LUAI_GCPAUSE;
 327   g->gcstepmul = LUAI_GCMUL;
 328   for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL;
 329   if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) {
 330     /* memory allocation error: free partial state */
 331     close_state(L);
 332     L = NULL;
 333   }
 334   return L;
 335 }
 336
 337
 338 LUA_API void lua_close (lua_State *L) {
 339   L = G(L)->mainthread;  /* only the main thread can be closed */
 340   lua_lock(L);
 341   close_state(L);
 342 }
 343
 344