ceph/src/civetweb/src/third_party/lua-5.3.1/src/lstate.c

   1 /*
   2 ** $Id: lstate.c,v 2.128 2015/03/04 13:31:21 roberto Exp $
   3 ** Global State
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7 #define lstate_c
   8 #define LUA_CORE
   9
  10 #include "lprefix.h"
  11
  12
  13 #include <stddef.h>
  14 #include <string.h>
  15
  16 #include "lua.h"
  17
  18 #include "lapi.h"
  19 #include "ldebug.h"
  20 #include "ldo.h"
  21 #include "lfunc.h"
  22 #include "lgc.h"
  23 #include "llex.h"
  24 #include "lmem.h"
  25 #include "lstate.h"
  26 #include "lstring.h"
  27 #include "ltable.h"
  28 #include "ltm.h"
  29
  30
  31 #if !defined(LUAI_GCPAUSE)
  32 #define LUAI_GCPAUSE    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 /*
  41 ** a macro to help the creation of a unique random seed when a state is
  42 ** created; the seed is used to randomize hashes.
  43 */
  44 #if !defined(luai_makeseed)
  45 #include <time.h>
  46 #define luai_makeseed()         cast(unsigned int, time(NULL))
  47 #endif
  48
  49
  50
  51 /*
  52 ** thread state + extra space
  53 */
  54 typedef struct LX {
  55   lu_byte extra_[LUA_EXTRASPACE];
  56   lua_State l;
  57 } LX;
  58
  59
  60 /*
  61 ** Main thread combines a thread state and the global state
  62 */
  63 typedef struct LG {
  64   LX l;
  65   global_State g;
  66 } LG;
  67
  68
  69
  70 #define fromstate(L)    (cast(LX *, cast(lu_byte *, (L)) - offsetof(LX, l)))
  71
  72
  73 /*
  74 ** Compute an initial seed as random as possible. Rely on Address Space
  75 ** Layout Randomization (if present) to increase randomness..
  76 */
  77 #define addbuff(b,p,e) \
  78   { size_t t = cast(size_t, e); \
  79     memcpy(buff + p, &t, sizeof(t)); p += sizeof(t); }
  80
  81 static unsigned int makeseed (lua_State *L) {
  82   char buff[4 * sizeof(size_t)];
  83   unsigned int h = luai_makeseed();
  84   int p = 0;
  85   addbuff(buff, p, L);  /* heap variable */
  86   addbuff(buff, p, &h);  /* local variable */
  87   addbuff(buff, p, luaO_nilobject);  /* global variable */
  88   addbuff(buff, p, &lua_newstate);  /* public function */
  89   lua_assert(p == sizeof(buff));
  90   return luaS_hash(buff, p, h);
  91 }
  92
  93
  94 /*
  95 ** set GCdebt to a new value keeping the value (totalbytes + GCdebt)
  96 ** invariant
  97 */
  98 void luaE_setdebt (global_State *g, l_mem debt) {
  99   g->totalbytes -= (debt - g->GCdebt);
 100   g->GCdebt = debt;
 101 }
 102
 103
 104 CallInfo *luaE_extendCI (lua_State *L) {
 105   CallInfo *ci = luaM_new(L, CallInfo);
 106   lua_assert(L->ci->next == NULL);
 107   L->ci->next = ci;
 108   ci->previous = L->ci;
 109   ci->next = NULL;
 110   return ci;
 111 }
 112
 113
 114 /*
 115 ** free all CallInfo structures not in use by a thread
 116 */
 117 void luaE_freeCI (lua_State *L) {
 118   CallInfo *ci = L->ci;
 119   CallInfo *next = ci->next;
 120   ci->next = NULL;
 121   while ((ci = next) != NULL) {
 122     next = ci->next;
 123     luaM_free(L, ci);
 124   }
 125 }
 126
 127
 128 /*
 129 ** free half of the CallInfo structures not in use by a thread
 130 */
 131 void luaE_shrinkCI (lua_State *L) {
 132   CallInfo *ci = L->ci;
 133   while (ci->next != NULL) {  /* while there is 'next' */
 134     CallInfo *next2 = ci->next->next;  /* next's next */
 135     if (next2 == NULL) break;
 136     luaM_free(L, ci->next);  /* remove next */
 137     ci->next = next2;  /* remove 'next' from the list */
 138     next2->previous = ci;
 139     ci = next2;
 140   }
 141 }
 142
 143
 144 static void stack_init (lua_State *L1, lua_State *L) {
 145   int i; CallInfo *ci;
 146   /* initialize stack array */
 147   L1->stack = luaM_newvector(L, BASIC_STACK_SIZE, TValue);
 148   L1->stacksize = BASIC_STACK_SIZE;
 149   for (i = 0; i < BASIC_STACK_SIZE; i++)
 150     setnilvalue(L1->stack + i);  /* erase new stack */
 151   L1->top = L1->stack;
 152   L1->stack_last = L1->stack + L1->stacksize - EXTRA_STACK;
 153   /* initialize first ci */
 154   ci = &L1->base_ci;
 155   ci->next = ci->previous = NULL;
 156   ci->callstatus = 0;
 157   ci->func = L1->top;
 158   setnilvalue(L1->top++);  /* 'function' entry for this 'ci' */
 159   ci->top = L1->top + LUA_MINSTACK;
 160   L1->ci = ci;
 161 }
 162
 163
 164 static void freestack (lua_State *L) {
 165   if (L->stack == NULL)
 166     return;  /* stack not completely built yet */
 167   L->ci = &L->base_ci;  /* free the entire 'ci' list */
 168   luaE_freeCI(L);
 169   luaM_freearray(L, L->stack, L->stacksize);  /* free stack array */
 170 }
 171
 172
 173 /*
 174 ** Create registry table and its predefined values
 175 */
 176 static void init_registry (lua_State *L, global_State *g) {
 177   TValue temp;
 178   /* create registry */
 179   Table *registry = luaH_new(L);
 180   sethvalue(L, &g->l_registry, registry);
 181   luaH_resize(L, registry, LUA_RIDX_LAST, 0);
 182   /* registry[LUA_RIDX_MAINTHREAD] = L */
 183   setthvalue(L, &temp, L);  /* temp = L */
 184   luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &temp);
 185   /* registry[LUA_RIDX_GLOBALS] = table of globals */
 186   sethvalue(L, &temp, luaH_new(L));  /* temp = new table (global table) */
 187   luaH_setint(L, registry, LUA_RIDX_GLOBALS, &temp);
 188 }
 189
 190
 191 /*
 192 ** open parts of the state that may cause memory-allocation errors.
 193 ** ('g->version' != NULL flags that the state was completely build)
 194 */
 195 static void f_luaopen (lua_State *L, void *ud) {
 196   global_State *g = G(L);
 197   UNUSED(ud);
 198   stack_init(L, L);  /* init stack */
 199   init_registry(L, g);
 200   luaS_init(L);
 201   luaT_init(L);
 202   luaX_init(L);
 203   g->gcrunning = 1;  /* allow gc */
 204   g->version = lua_version(NULL);
 205   luai_userstateopen(L);
 206 }
 207
 208
 209 /*
 210 ** preinitialize a thread with consistent values without allocating
 211 ** any memory (to avoid errors)
 212 */
 213 static void preinit_thread (lua_State *L, global_State *g) {
 214   G(L) = g;
 215   L->stack = NULL;
 216   L->ci = NULL;
 217   L->stacksize = 0;
 218   L->twups = L;  /* thread has no upvalues */
 219   L->errorJmp = NULL;
 220   L->nCcalls = 0;
 221   L->hook = NULL;
 222   L->hookmask = 0;
 223   L->basehookcount = 0;
 224   L->allowhook = 1;
 225   resethookcount(L);
 226   L->openupval = NULL;
 227   L->nny = 1;
 228   L->status = LUA_OK;
 229   L->errfunc = 0;
 230 }
 231
 232
 233 static void close_state (lua_State *L) {
 234   global_State *g = G(L);
 235   luaF_close(L, L->stack);  /* close all upvalues for this thread */
 236   luaC_freeallobjects(L);  /* collect all objects */
 237   if (g->version)  /* closing a fully built state? */
 238     luai_userstateclose(L);
 239   luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size);
 240   luaZ_freebuffer(L, &g->buff);
 241   freestack(L);
 242   lua_assert(gettotalbytes(g) == sizeof(LG));
 243   (*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0);  /* free main block */
 244 }
 245
 246
 247 LUA_API lua_State *lua_newthread (lua_State *L) {
 248   global_State *g = G(L);
 249   lua_State *L1;
 250   lua_lock(L);
 251   luaC_checkGC(L);
 252   /* create new thread */
 253   L1 = &cast(LX *, luaM_newobject(L, LUA_TTHREAD, sizeof(LX)))->l;
 254   L1->marked = luaC_white(g);
 255   L1->tt = LUA_TTHREAD;
 256   /* link it on list 'allgc' */
 257   L1->next = g->allgc;
 258   g->allgc = obj2gco(L1);
 259   /* anchor it on L stack */
 260   setthvalue(L, L->top, L1);
 261   api_incr_top(L);
 262   preinit_thread(L1, g);
 263   L1->hookmask = L->hookmask;
 264   L1->basehookcount = L->basehookcount;
 265   L1->hook = L->hook;
 266   resethookcount(L1);
 267   /* initialize L1 extra space */
 268   memcpy(lua_getextraspace(L1), lua_getextraspace(g->mainthread),
 269          LUA_EXTRASPACE);
 270   luai_userstatethread(L, L1);
 271   stack_init(L1, L);  /* init stack */
 272   lua_unlock(L);
 273   return L1;
 274 }
 275
 276
 277 void luaE_freethread (lua_State *L, lua_State *L1) {
 278   LX *l = fromstate(L1);
 279   luaF_close(L1, L1->stack);  /* close all upvalues for this thread */
 280   lua_assert(L1->openupval == NULL);
 281   luai_userstatefree(L, L1);
 282   freestack(L1);
 283   luaM_free(L, l);
 284 }
 285
 286
 287 LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
 288   int i;
 289   lua_State *L;
 290   global_State *g;
 291   LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG)));
 292   if (l == NULL) return NULL;
 293   L = &l->l.l;
 294   g = &l->g;
 295   L->next = NULL;
 296   L->tt = LUA_TTHREAD;
 297   g->currentwhite = bitmask(WHITE0BIT);
 298   L->marked = luaC_white(g);
 299   preinit_thread(L, g);
 300   g->frealloc = f;
 301   g->ud = ud;
 302   g->mainthread = L;
 303   g->seed = makeseed(L);
 304   g->gcrunning = 0;  /* no GC while building state */
 305   g->GCestimate = 0;
 306   g->strt.size = g->strt.nuse = 0;
 307   g->strt.hash = NULL;
 308   setnilvalue(&g->l_registry);
 309   luaZ_initbuffer(L, &g->buff);
 310   g->panic = NULL;
 311   g->version = NULL;
 312   g->gcstate = GCSpause;
 313   g->gckind = KGC_NORMAL;
 314   g->allgc = g->finobj = g->tobefnz = g->fixedgc = NULL;
 315   g->sweepgc = NULL;
 316   g->gray = g->grayagain = NULL;
 317   g->weak = g->ephemeron = g->allweak = NULL;
 318   g->twups = NULL;
 319   g->totalbytes = sizeof(LG);
 320   g->GCdebt = 0;
 321   g->gcfinnum = 0;
 322   g->gcpause = LUAI_GCPAUSE;
 323   g->gcstepmul = LUAI_GCMUL;
 324   for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL;
 325   if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) {
 326     /* memory allocation error: free partial state */
 327     close_state(L);
 328     L = NULL;
 329   }
 330   return L;
 331 }
 332
 333
 334 LUA_API void lua_close (lua_State *L) {
 335   L = G(L)->mainthread;  /* only the main thread can be closed */
 336   lua_lock(L);
 337   close_state(L);
 338 }
 339
 340