module/lua/lstate.c

   1 /* BEGIN CSTYLED */
   2 /*
   3 ** $Id: lstate.c,v 2.99.1.2 2013/11/08 17:45:31 roberto Exp $
   4 ** Global State
   5 ** See Copyright Notice in lua.h
   6 */
   7
   8
   9 #define lstate_c
  10 #define LUA_CORE
  11
  12 #include <sys/lua/lua.h>
  13
  14 #include "lapi.h"
  15 #include "ldebug.h"
  16 #include "ldo.h"
  17 #include "lfunc.h"
  18 #include "lgc.h"
  19 #include "llex.h"
  20 #include "lmem.h"
  21 #include "lstate.h"
  22 #include "lstring.h"
  23 #include "ltable.h"
  24 #include "ltm.h"
  25
  26
  27 #if !defined(LUAI_GCPAUSE)
  28 #define LUAI_GCPAUSE    200  /* 200% */
  29 #endif
  30
  31 #if !defined(LUAI_GCMAJOR)
  32 #define LUAI_GCMAJOR    200  /* 200% */
  33 #endif
  34
  35 #if !defined(LUAI_GCMUL)
  36 #define LUAI_GCMUL      200 /* GC runs 'twice the speed' of memory allocation */
  37 #endif
  38
  39
  40 #define MEMERRMSG       "not enough memory"
  41
  42
  43 /*
  44 ** a macro to help the creation of a unique random seed when a state is
  45 ** created; the seed is used to randomize hashes.
  46 */
  47 #if !defined(luai_makeseed)
  48 #define luai_makeseed()         cast(unsigned int, gethrtime())
  49 #endif
  50
  51
  52
  53 /*
  54 ** thread state + extra space
  55 */
  56 typedef struct LX {
  57 #if defined(LUAI_EXTRASPACE)
  58   char buff[LUAI_EXTRASPACE];
  59 #endif
  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. In ANSI, rely on
  79 ** Address Space Layout Randomization (if present) to increase
  80 ** randomness..
  81 */
  82 #define addbuff(b,p,e) \
  83   { size_t t = cast(size_t, e); \
  84     memcpy(buff + p, &t, sizeof(t)); p += sizeof(t); }
  85
  86 static unsigned int makeseed (lua_State *L) {
  87   char buff[4 * sizeof(size_t)];
  88   unsigned int h = luai_makeseed();
  89   int p = 0;
  90   addbuff(buff, p, L);  /* heap variable */
  91   addbuff(buff, p, &h);  /* local variable */
  92   addbuff(buff, p, luaO_nilobject);  /* global variable */
  93   addbuff(buff, p, &lua_newstate);  /* public function */
  94   lua_assert(p == sizeof(buff));
  95   return luaS_hash(buff, p, h);
  96 }
  97
  98
  99 /*
 100 ** set GCdebt to a new value keeping the value (totalbytes + GCdebt)
 101 ** invariant
 102 */
 103 void luaE_setdebt (global_State *g, l_mem debt) {
 104   g->totalbytes -= (debt - g->GCdebt);
 105   g->GCdebt = debt;
 106 }
 107
 108
 109 CallInfo *luaE_extendCI (lua_State *L) {
 110   CallInfo *ci = luaM_new(L, CallInfo);
 111   lua_assert(L->ci->next == NULL);
 112   L->ci->next = ci;
 113   ci->previous = L->ci;
 114   ci->next = NULL;
 115   return ci;
 116 }
 117
 118
 119 void luaE_freeCI (lua_State *L) {
 120   CallInfo *ci = L->ci;
 121   CallInfo *next = ci->next;
 122   ci->next = NULL;
 123   while ((ci = next) != NULL) {
 124     next = ci->next;
 125     luaM_free(L, ci);
 126   }
 127 }
 128
 129
 130 static void stack_init (lua_State *L1, lua_State *L) {
 131   int i; CallInfo *ci;
 132   /* initialize stack array */
 133   L1->stack = luaM_newvector(L, BASIC_STACK_SIZE, TValue);
 134   L1->stacksize = BASIC_STACK_SIZE;
 135   for (i = 0; i < BASIC_STACK_SIZE; i++)
 136     setnilvalue(L1->stack + i);  /* erase new stack */
 137   L1->top = L1->stack;
 138   L1->stack_last = L1->stack + L1->stacksize - EXTRA_STACK;
 139   /* initialize first ci */
 140   ci = &L1->base_ci;
 141   ci->next = ci->previous = NULL;
 142   ci->callstatus = 0;
 143   ci->func = L1->top;
 144   setnilvalue(L1->top++);  /* 'function' entry for this 'ci' */
 145   ci->top = L1->top + LUA_MINSTACK;
 146   L1->ci = ci;
 147 }
 148
 149
 150 static void freestack (lua_State *L) {
 151   if (L->stack == NULL)
 152     return;  /* stack not completely built yet */
 153   L->ci = &L->base_ci;  /* free the entire 'ci' list */
 154   luaE_freeCI(L);
 155   luaM_freearray(L, L->stack, L->stacksize);  /* free stack array */
 156 }
 157
 158
 159 /*
 160 ** Create registry table and its predefined values
 161 */
 162 static void init_registry (lua_State *L, global_State *g) {
 163   TValue mt;
 164   /* create registry */
 165   Table *registry = luaH_new(L);
 166   sethvalue(L, &g->l_registry, registry);
 167   luaH_resize(L, registry, LUA_RIDX_LAST, 0);
 168   /* registry[LUA_RIDX_MAINTHREAD] = L */
 169   setthvalue(L, &mt, L);
 170   luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &mt);
 171   /* registry[LUA_RIDX_GLOBALS] = table of globals */
 172   sethvalue(L, &mt, luaH_new(L));
 173   luaH_setint(L, registry, LUA_RIDX_GLOBALS, &mt);
 174 }
 175
 176
 177 /*
 178 ** open parts of the state that may cause memory-allocation errors
 179 */
 180 static void f_luaopen (lua_State *L, void *ud) {
 181   global_State *g = G(L);
 182   UNUSED(ud);
 183   stack_init(L, L);  /* init stack */
 184   init_registry(L, g);
 185   luaS_resize(L, MINSTRTABSIZE);  /* initial size of string table */
 186   luaT_init(L);
 187   luaX_init(L);
 188   /* pre-create memory-error message */
 189   g->memerrmsg = luaS_newliteral(L, MEMERRMSG);
 190   luaS_fix(g->memerrmsg);  /* it should never be collected */
 191   g->gcrunning = 1;  /* allow gc */
 192   g->version = lua_version(NULL);
 193   luai_userstateopen(L);
 194 }
 195
 196
 197 /*
 198 ** preinitialize a state with consistent values without allocating
 199 ** any memory (to avoid errors)
 200 */
 201 static void preinit_state (lua_State *L, global_State *g) {
 202   G(L) = g;
 203   L->stack = NULL;
 204   L->ci = NULL;
 205   L->stacksize = 0;
 206   L->errorJmp = NULL;
 207   L->nCcalls = 0;
 208   L->hook = NULL;
 209   L->hookmask = 0;
 210   L->basehookcount = 0;
 211   L->allowhook = 1;
 212   resethookcount(L);
 213   L->openupval = NULL;
 214   L->nny = 1;
 215   L->status = LUA_OK;
 216   L->errfunc = 0;
 217   L->runerror = 0;
 218 }
 219
 220
 221 static void close_state (lua_State *L) {
 222   global_State *g = G(L);
 223   luaF_close(L, L->stack);  /* close all upvalues for this thread */
 224   luaC_freeallobjects(L);  /* collect all objects */
 225   if (g->version)  /* closing a fully built state? */
 226     luai_userstateclose(L);
 227   luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size);
 228   luaZ_freebuffer(L, &g->buff);
 229   freestack(L);
 230   lua_assert(gettotalbytes(g) == sizeof(LG));
 231   (*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0);  /* free main block */
 232 }
 233
 234
 235 LUA_API lua_State *lua_newthread (lua_State *L) {
 236   lua_State *L1;
 237   lua_lock(L);
 238   luaC_checkGC(L);
 239   L1 = &luaC_newobj(L, LUA_TTHREAD, sizeof(LX), NULL, offsetof(LX, l))->th;
 240   setthvalue(L, L->top, L1);
 241   api_incr_top(L);
 242   preinit_state(L1, G(L));
 243   L1->hookmask = L->hookmask;
 244   L1->basehookcount = L->basehookcount;
 245   L1->hook = L->hook;
 246   resethookcount(L1);
 247   luai_userstatethread(L, L1);
 248   stack_init(L1, L);  /* init stack */
 249   lua_unlock(L);
 250   return L1;
 251 }
 252
 253
 254 void luaE_freethread (lua_State *L, lua_State *L1) {
 255   LX *l = fromstate(L1);
 256   luaF_close(L1, L1->stack);  /* close all upvalues for this thread */
 257   lua_assert(L1->openupval == NULL);
 258   luai_userstatefree(L, L1);
 259   freestack(L1);
 260   luaM_free(L, l);
 261 }
 262
 263
 264 LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
 265   int i;
 266   lua_State *L;
 267   global_State *g;
 268   LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG)));
 269   if (l == NULL) return NULL;
 270   L = &l->l.l;
 271   g = &l->g;
 272   L->next = NULL;
 273   L->tt = LUA_TTHREAD;
 274   g->currentwhite = bit2mask(WHITE0BIT, FIXEDBIT);
 275   L->marked = luaC_white(g);
 276   g->gckind = KGC_NORMAL;
 277   preinit_state(L, g);
 278   g->frealloc = f;
 279   g->ud = ud;
 280   g->mainthread = L;
 281   g->seed = makeseed(L);
 282   g->uvhead.u.l.prev = &g->uvhead;
 283   g->uvhead.u.l.next = &g->uvhead;
 284   g->gcrunning = 0;  /* no GC while building state */
 285   g->GCestimate = 0;
 286   g->strt.size = 0;
 287   g->strt.nuse = 0;
 288   g->strt.hash = NULL;
 289   setnilvalue(&g->l_registry);
 290   luaZ_initbuffer(L, &g->buff);
 291   g->panic = NULL;
 292   g->version = NULL;
 293   g->gcstate = GCSpause;
 294   g->allgc = NULL;
 295   g->finobj = NULL;
 296   g->tobefnz = NULL;
 297   g->sweepgc = g->sweepfin = NULL;
 298   g->gray = g->grayagain = NULL;
 299   g->weak = g->ephemeron = g->allweak = NULL;
 300   g->totalbytes = sizeof(LG);
 301   g->GCdebt = 0;
 302   g->gcpause = LUAI_GCPAUSE;
 303   g->gcmajorinc = LUAI_GCMAJOR;
 304   g->gcstepmul = LUAI_GCMUL;
 305   for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL;
 306   if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) {
 307     /* memory allocation error: free partial state */
 308     close_state(L);
 309     L = NULL;
 310   }
 311   return L;
 312 }
 313
 314
 315 LUA_API void lua_close (lua_State *L) {
 316   L = G(L)->mainthread;  /* only the main thread can be closed */
 317   lua_lock(L);
 318   close_state(L);
 319 }
 320 /* END CSTYLED */