/*

** $Id: lstate.c,v 2.99.1.2 2013/11/08 17:45:31 roberto Exp $

** Global State

** See Copyright Notice in lua.h

*/

#include <stddef.h>

#include <string.h>

#define lstate_c

#define LUA_CORE

#include "lua.h"

#include "lapi.h"

#include "ldebug.h"

#include "ldo.h"

#include "lfunc.h"

#include "lgc.h"

#include "llex.h"

#include "lmem.h"

#include "lstate.h"

#include "lstring.h"

#include "ltable.h"

#include "ltm.h"

#if !defined(LUAI_GCPAUSE)

#define LUAI_GCPAUSE 200 /* 200% */

#endif

#if !defined(LUAI_GCMAJOR)

#define LUAI_GCMAJOR 200 /* 200% */

#endif

#if !defined(LUAI_GCMUL)

#define LUAI_GCMUL 200 /* GC runs 'twice the speed' of memory allocation */

#endif

#define MEMERRMSG "not enough memory"

/*

** a macro to help the creation of a unique random seed when a state is

** created; the seed is used to randomize hashes.

*/

#if !defined(luai_makeseed)

#include <time.h>

#define luai_makeseed() cast(unsigned int, time(NULL))

#endif

/*

** thread state + extra space

*/

typedef struct LX {

} LX;

/*

** Main thread combines a thread state and the global state

*/

typedef struct LG {

LX l;

global_State g;

} LG;

#define fromstate(L) (cast(LX *, cast(lu_byte *, (L)) - offsetof(LX, l)))

/*

** Compute an initial seed as random as possible. In ANSI, rely on

** Address Space Layout Randomization (if present) to increase

** randomness..

*/

#define addbuff(b,p,e) \

{ size_t t = cast(size_t, e); \

memcpy(buff + p, &t, sizeof(t)); p += sizeof(t); }

static unsigned int makeseed (lua_State *L) {

char buff[4 * sizeof(size_t)];

unsigned int h = luai_makeseed();

int p = 0;

addbuff(buff, p, L); /* heap variable */

addbuff(buff, p, &h); /* local variable */

addbuff(buff, p, luaO_nilobject); /* global variable */

addbuff(buff, p, &lua_newstate); /* public function */

lua_assert(p == sizeof(buff));

return luaS_hash(buff, p, h);

}

/*

** set GCdebt to a new value keeping the value (totalbytes + GCdebt)

** invariant

*/

void luaE_setdebt (global_State *g, l_mem debt) {

g->totalbytes -= (debt - g->GCdebt);

g->GCdebt = debt;

}

CallInfo *luaE_extendCI (lua_State *L) {

CallInfo *ci = luaM_new(L, CallInfo);

lua_assert(L->ci->next == NULL);

L->ci->next = ci;

ci->previous = L->ci;

ci->next = NULL;

return ci;

}

void luaE_freeCI (lua_State *L) {

CallInfo *ci = L->ci;

CallInfo *next = ci->next;

ci->next = NULL;

while ((ci = next) != NULL) {

next = ci->next;

luaM_free(L, ci);

}

}

static void stack_init (lua_State *L1, lua_State *L) {

int i; CallInfo *ci;

/* initialize stack array */

L1->stack = luaM_newvector(L, BASIC_STACK_SIZE, TValue);

L1->stacksize = BASIC_STACK_SIZE;

for (i = 0; i < BASIC_STACK_SIZE; i++)

setnilvalue(L1->stack + i); /* erase new stack */

L1->top = L1->stack;

L1->stack_last = L1->stack + L1->stacksize - EXTRA_STACK;

/* initialize first ci */

ci = &L1->base_ci;

ci->next = ci->previous = NULL;

ci->callstatus = 0;

ci->func = L1->top;

setnilvalue(L1->top++); /* 'function' entry for this 'ci' */

ci->top = L1->top + LUA_MINSTACK;

L1->ci = ci;

}

static void freestack (lua_State *L) {

if (L->stack == NULL)

return; /* stack not completely built yet */

L->ci = &L->base_ci; /* free the entire 'ci' list */

luaE_freeCI(L);

luaM_freearray(L, L->stack, L->stacksize); /* free stack array */

}

/*

** Create registry table and its predefined values

*/

static void init_registry (lua_State *L, global_State *g) {

TValue mt;

/* create registry */

Table *registry = luaH_new(L);

sethvalue(L, &g->l_registry, registry);

luaH_resize(L, registry, LUA_RIDX_LAST, 0);

/* registry[LUA_RIDX_MAINTHREAD] = L */

setthvalue(L, &mt, L);

luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &mt);

/* registry[LUA_RIDX_GLOBALS] = table of globals */

sethvalue(L, &mt, luaH_new(L));

luaH_setint(L, registry, LUA_RIDX_GLOBALS, &mt);

}

/*

** open parts of the state that may cause memory-allocation errors

*/

static void f_luaopen (lua_State *L, void *ud) {

global_State *g = G(L);

UNUSED(ud);

stack_init(L, L); /* init stack */

init_registry(L, g);

luaS_resize(L, MINSTRTABSIZE); /* initial size of string table */

luaT_init(L);

luaX_init(L);

/* pre-create memory-error message */

g->memerrmsg = luaS_newliteral(L, MEMERRMSG);

luaS_fix(g->memerrmsg); /* it should never be collected */

g->gcrunning = 1; /* allow gc */

g->version = lua_version(NULL);

luai_userstateopen(L);

}

/*

** preinitialize a state with consistent values without allocating

** any memory (to avoid errors)

*/

static void preinit_state (lua_State *L, global_State *g) {

G(L) = g;

L->stack = NULL;

L->ci = NULL;

L->stacksize = 0;

L->errorJmp = NULL;

L->nCcalls = 0;

L->hook = NULL;

L->hookmask = 0;

L->basehookcount = 0;

L->allowhook = 1;

resethookcount(L);

L->openupval = NULL;

L->nny = 1;

L->status = LUA_OK;

L->errfunc = 0;

}

static void close_state (lua_State *L) {

global_State *g = G(L);

luaF_close(L, L->stack); /* close all upvalues for this thread */

luaC_freeallobjects(L); /* collect all objects */

if (g->version) /* closing a fully built state? */

luai_userstateclose(L);

luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size);

luaZ_freebuffer(L, &g->buff);

freestack(L);

lua_assert(gettotalbytes(g) == sizeof(LG));

(*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0); /* free main block */

}

LUA_API lua_State *lua_newthread (lua_State *L) {

lua_State *L1;

lua_lock(L);

luaC_checkGC(L);

L1 = &luaC_newobj(L, LUA_TTHREAD, sizeof(LX), NULL, offsetof(LX, l))->th;

setthvalue(L, L->top, L1);

api_incr_top(L);

preinit_state(L1, G(L));

L1->hookmask = L->hookmask;

L1->basehookcount = L->basehookcount;

L1->hook = L->hook;

resethookcount(L1);

luai_userstatethread(L, L1);

stack_init(L1, L); /* init stack */

lua_unlock(L);

return L1;

}

void luaE_freethread (lua_State *L, lua_State *L1) {

LX *l = fromstate(L1);

luaF_close(L1, L1->stack); /* close all upvalues for this thread */

lua_assert(L1->openupval == NULL);

luai_userstatefree(L, L1);

freestack(L1);

luaM_free(L, l);

}

LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {

int i;

lua_State *L;

global_State *g;

LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG)));

if (l == NULL) return NULL;

L = &l->l.l;

g = &l->g;

L->next = NULL;

L->tt = LUA_TTHREAD;

g->currentwhite = bit2mask(WHITE0BIT, FIXEDBIT);

L->marked = luaC_white(g);

g->gckind = KGC_NORMAL;

preinit_state(L, g);

g->frealloc = f;

g->ud = ud;

g->mainthread = L;

g->seed = makeseed(L);

g->uvhead.u.l.prev = &g->uvhead;

g->uvhead.u.l.next = &g->uvhead;

g->gcrunning = 0; /* no GC while building state */

g->GCestimate = 0;

g->strt.size = 0;

g->strt.nuse = 0;

g->strt.hash = NULL;

setnilvalue(&g->l_registry);

luaZ_initbuffer(L, &g->buff);

g->panic = NULL;

g->version = NULL;

g->gcstate = GCSpause;

g->allgc = NULL;

g->finobj = NULL;

g->tobefnz = NULL;

g->sweepgc = g->sweepfin = NULL;

g->gray = g->grayagain = NULL;

g->weak = g->ephemeron = g->allweak = NULL;

g->totalbytes = sizeof(LG);

g->GCdebt = 0;

g->gcpause = LUAI_GCPAUSE;

g->gcmajorinc = LUAI_GCMAJOR;

g->gcstepmul = LUAI_GCMUL;

for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL;

if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) {

/* memory allocation error: free partial state */

close_state(L);

L = NULL;

}

return L;

}

LUA_API void lua_close (lua_State *L) {

L = G(L)->mainthread; /* only the main thread can be closed */

lua_lock(L);

close_state(L);

}