1 /* 2 ** $Id: lstate.c,v 2.99 2012/10/02 17:40:53 roberto Exp $ 3 ** Global State 4 ** See Copyright Notice in lua.h 5 */ 6 7 8 #include <stddef.h> 9 #include <string.h> 10 11 #define lstate_c 12 #define LUA_CORE 13 14 #include "lua.h" 15 16 #include "lapi.h" 17 #include "ldebug.h" 18 #include "ldo.h" 19 #include "lfunc.h" 20 #include "lgc.h" 21 #include "llex.h" 22 #include "lmem.h" 23 #include "lstate.h" 24 #include "lstring.h" 25 #include "ltable.h" 26 #include "ltm.h" 27 28 29 #if !defined(LUAI_GCPAUSE) 30 #define LUAI_GCPAUSE 200 /* 200% */ 31 #endif 32 33 #if !defined(LUAI_GCMAJOR) 34 #define LUAI_GCMAJOR 200 /* 200% */ 35 #endif 36 37 #if !defined(LUAI_GCMUL) 38 #define LUAI_GCMUL 200 /* GC runs 'twice the speed' of memory allocation */ 39 #endif 40 41 42 #define MEMERRMSG "not enough memory" 43 44 45 /* 46 ** a macro to help the creation of a unique random seed when a state is 47 ** created; the seed is used to randomize hashes. 48 */ 49 #if !defined(luai_makeseed) 50 #include <time.h> 51 #define luai_makeseed() cast(unsigned int, time(NULL)) 52 #endif 53 54 55 56 /* 57 ** thread state + extra space 58 */ 59 typedef struct LX { 60 #if defined(LUAI_EXTRASPACE) 61 char buff[LUAI_EXTRASPACE]; 62 #endif 63 lua_State l; 64 } LX; 65 66 67 /* 68 ** Main thread combines a thread state and the global state 69 */ 70 typedef struct LG { 71 LX l; 72 global_State g; 73 } LG; 74 75 76 77 #define fromstate(L) (cast(LX *, cast(lu_byte *, (L)) - offsetof(LX, l))) 78 79 80 /* 81 ** Compute an initial seed as random as possible. In ANSI, rely on 82 ** Address Space Layout Randomization (if present) to increase 83 ** randomness.. 84 */ 85 #define addbuff(b,p,e) \ 86 { size_t t = cast(size_t, e); \ 87 memcpy(buff + p, &t, sizeof(t)); p += sizeof(t); } 88 89 static unsigned int makeseed (lua_State *L) { 90 char buff[4 * sizeof(size_t)]; 91 unsigned int h = luai_makeseed(); 92 int p = 0; 93 addbuff(buff, p, L); /* heap variable */ 94 addbuff(buff, p, &h); /* local variable */ 95 addbuff(buff, p, luaO_nilobject); /* global variable */ 96 addbuff(buff, p, &lua_newstate); /* public function */ 97 lua_assert(p == sizeof(buff)); 98 return luaS_hash(buff, p, h); 99 } 100 101 102 /* 103 ** set GCdebt to a new value keeping the value (totalbytes + GCdebt) 104 ** invariant 105 */ 106 void luaE_setdebt (global_State *g, l_mem debt) { 107 g->totalbytes -= (debt - g->GCdebt); 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 return ci; 119 } 120 121 122 void luaE_freeCI (lua_State *L) { 123 CallInfo *ci = L->ci; 124 CallInfo *next = ci->next; 125 ci->next = NULL; 126 while ((ci = next) != NULL) { 127 next = ci->next; 128 luaM_free(L, ci); 129 } 130 } 131 132 133 static void stack_init (lua_State *L1, lua_State *L) { 134 int i; CallInfo *ci; 135 /* initialize stack array */ 136 L1->stack = luaM_newvector(L, BASIC_STACK_SIZE, TValue); 137 L1->stacksize = BASIC_STACK_SIZE; 138 for (i = 0; i < BASIC_STACK_SIZE; i++) 139 setnilvalue(L1->stack + i); /* erase new stack */ 140 L1->top = L1->stack; 141 L1->stack_last = L1->stack + L1->stacksize - EXTRA_STACK; 142 /* initialize first ci */ 143 ci = &L1->base_ci; 144 ci->next = ci->previous = NULL; 145 ci->callstatus = 0; 146 ci->func = L1->top; 147 setnilvalue(L1->top++); /* 'function' entry for this 'ci' */ 148 ci->top = L1->top + LUA_MINSTACK; 149 L1->ci = ci; 150 } 151 152 153 static void freestack (lua_State *L) { 154 if (L->stack == NULL) 155 return; /* stack not completely built yet */ 156 L->ci = &L->base_ci; /* free the entire 'ci' list */ 157 luaE_freeCI(L); 158 luaM_freearray(L, L->stack, L->stacksize); /* free stack array */ 159 } 160 161 162 /* 163 ** Create registry table and its predefined values 164 */ 165 static void init_registry (lua_State *L, global_State *g) { 166 TValue mt; 167 /* create registry */ 168 Table *registry = luaH_new(L); 169 sethvalue(L, &g->l_registry, registry); 170 luaH_resize(L, registry, LUA_RIDX_LAST, 0); 171 /* registry[LUA_RIDX_MAINTHREAD] = L */ 172 setthvalue(L, &mt, L); 173 luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &mt); 174 /* registry[LUA_RIDX_GLOBALS] = table of globals */ 175 sethvalue(L, &mt, luaH_new(L)); 176 luaH_setint(L, registry, LUA_RIDX_GLOBALS, &mt); 177 } 178 179 180 /* 181 ** open parts of the state that may cause memory-allocation errors 182 */ 183 static void f_luaopen (lua_State *L, void *ud) { 184 global_State *g = G(L); 185 UNUSED(ud); 186 stack_init(L, L); /* init stack */ 187 init_registry(L, g); 188 luaS_resize(L, MINSTRTABSIZE); /* initial size of string table */ 189 luaT_init(L); 190 luaX_init(L); 191 /* pre-create memory-error message */ 192 g->memerrmsg = luaS_newliteral(L, MEMERRMSG); 193 luaS_fix(g->memerrmsg); /* it should never be collected */ 194 g->gcrunning = 1; /* allow gc */ 195 } 196 197 198 /* 199 ** preinitialize a state with consistent values without allocating 200 ** any memory (to avoid errors) 201 */ 202 static void preinit_state (lua_State *L, global_State *g) { 203 G(L) = g; 204 L->stack = NULL; 205 L->ci = NULL; 206 L->stacksize = 0; 207 L->errorJmp = NULL; 208 L->nCcalls = 0; 209 L->hook = NULL; 210 L->hookmask = 0; 211 L->basehookcount = 0; 212 L->allowhook = 1; 213 resethookcount(L); 214 L->openupval = NULL; 215 L->nny = 1; 216 L->status = LUA_OK; 217 L->errfunc = 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 luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size); 226 luaZ_freebuffer(L, &g->buff); 227 freestack(L); 228 lua_assert(gettotalbytes(g) == sizeof(LG)); 229 (*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0); /* free main block */ 230 } 231 232 233 LUA_API lua_State *lua_newthread (lua_State *L) { 234 lua_State *L1; 235 lua_lock(L); 236 luaC_checkGC(L); 237 L1 = &luaC_newobj(L, LUA_TTHREAD, sizeof(LX), NULL, offsetof(LX, l))->th; 238 setthvalue(L, L->top, L1); 239 api_incr_top(L); 240 preinit_state(L1, G(L)); 241 L1->hookmask = L->hookmask; 242 L1->basehookcount = L->basehookcount; 243 L1->hook = L->hook; 244 resethookcount(L1); 245 luai_userstatethread(L, L1); 246 stack_init(L1, L); /* init stack */ 247 lua_unlock(L); 248 return L1; 249 } 250 251 252 void luaE_freethread (lua_State *L, lua_State *L1) { 253 LX *l = fromstate(L1); 254 luaF_close(L1, L1->stack); /* close all upvalues for this thread */ 255 lua_assert(L1->openupval == NULL); 256 luai_userstatefree(L, L1); 257 freestack(L1); 258 luaM_free(L, l); 259 } 260 261 262 LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) { 263 int i; 264 lua_State *L; 265 global_State *g; 266 LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG))); 267 if (l == NULL) return NULL; 268 L = &l->l.l; 269 g = &l->g; 270 L->next = NULL; 271 L->tt = LUA_TTHREAD; 272 g->currentwhite = bit2mask(WHITE0BIT, FIXEDBIT); 273 L->marked = luaC_white(g); 274 g->gckind = KGC_NORMAL; 275 preinit_state(L, g); 276 g->frealloc = f; 277 g->ud = ud; 278 g->mainthread = L; 279 g->seed = makeseed(L); 280 g->uvhead.u.l.prev = &g->uvhead; 281 g->uvhead.u.l.next = &g->uvhead; 282 g->gcrunning = 0; /* no GC while building state */ 283 g->GCestimate = 0; 284 g->strt.size = 0; 285 g->strt.nuse = 0; 286 g->strt.hash = NULL; 287 setnilvalue(&g->l_registry); 288 luaZ_initbuffer(L, &g->buff); 289 g->panic = NULL; 290 g->version = lua_version(NULL); 291 g->gcstate = GCSpause; 292 g->allgc = NULL; 293 g->finobj = NULL; 294 g->tobefnz = NULL; 295 g->sweepgc = g->sweepfin = NULL; 296 g->gray = g->grayagain = NULL; 297 g->weak = g->ephemeron = g->allweak = NULL; 298 g->totalbytes = sizeof(LG); 299 g->GCdebt = 0; 300 g->gcpause = LUAI_GCPAUSE; 301 g->gcmajorinc = LUAI_GCMAJOR; 302 g->gcstepmul = LUAI_GCMUL; 303 for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL; 304 if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) { 305 /* memory allocation error: free partial state */ 306 close_state(L); 307 L = NULL; 308 } 309 else 310 luai_userstateopen(L); 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 luai_userstateclose(L); 319 close_state(L); 320 } 321 322 323
