1 /* 2 ** $Id: lstate.c,v 2.99.1.2 2013/11/08 17:45:31 roberto Exp $ 3 ** Global State 4 ** See Copyright Notice in lua.h 5 */ 6 7 8 #define lstate_c 9 #define LUA_CORE 10 11 #include <sys/lua/lua.h> 12 13 #include "lapi.h" 14 #include "ldebug.h" 15 #include "ldo.h" 16 #include "lfunc.h" 17 #include "lgc.h" 18 #include "llex.h" 19 #include "lmem.h" 20 #include "lstate.h" 21 #include "lstring.h" 22 #include "ltable.h" 23 #include "ltm.h" 24 25 26 #if !defined(LUAI_GCPAUSE) 27 #define LUAI_GCPAUSE 200 /* 200% */ 28 #endif 29 30 #if !defined(LUAI_GCMAJOR) 31 #define LUAI_GCMAJOR 200 /* 200% */ 32 #endif 33 34 #if !defined(LUAI_GCMUL) 35 #define LUAI_GCMUL 200 /* GC runs 'twice the speed' of memory allocation */ 36 #endif 37 38 39 #define MEMERRMSG "not enough memory" 40 41 42 /* 43 ** a macro to help the creation of a unique random seed when a state is 44 ** created; the seed is used to randomize hashes. 45 */ 46 #if !defined(luai_makeseed) 47 #define luai_makeseed() cast(unsigned int, gethrtime()) 48 #endif 49 50 51 52 /* 53 ** thread state + extra space 54 */ 55 typedef struct LX { 56 #if defined(LUAI_EXTRASPACE) 57 char buff[LUAI_EXTRASPACE]; 58 #endif 59 lua_State l; 60 } LX; 61 62 63 /* 64 ** Main thread combines a thread state and the global state 65 */ 66 typedef struct LG { 67 LX l; 68 global_State g; 69 } LG; 70 71 72 73 #define fromstate(L) (cast(LX *, cast(lu_byte *, (L)) - offsetof(LX, l))) 74 75 76 /* 77 ** Compute an initial seed as random as possible. In ANSI, rely on 78 ** Address Space Layout Randomization (if present) to increase 79 ** 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 void luaE_freeCI (lua_State *L) { 119 CallInfo *ci = L->ci; 120 CallInfo *next = ci->next; 121 ci->next = NULL; 122 while ((ci = next) != NULL) { 123 next = ci->next; 124 luaM_free(L, ci); 125 } 126 } 127 128 129 static void stack_init (lua_State *L1, lua_State *L) { 130 int i; CallInfo *ci; 131 /* initialize stack array */ 132 L1->stack = luaM_newvector(L, BASIC_STACK_SIZE, TValue); 133 L1->stacksize = BASIC_STACK_SIZE; 134 for (i = 0; i < BASIC_STACK_SIZE; i++) 135 setnilvalue(L1->stack + i); /* erase new stack */ 136 L1->top = L1->stack; 137 L1->stack_last = L1->stack + L1->stacksize - EXTRA_STACK; 138 /* initialize first ci */ 139 ci = &L1->base_ci; 140 ci->next = ci->previous = NULL; 141 ci->callstatus = 0; 142 ci->func = L1->top; 143 setnilvalue(L1->top++); /* 'function' entry for this 'ci' */ 144 ci->top = L1->top + LUA_MINSTACK; 145 L1->ci = ci; 146 } 147 148 149 static void freestack (lua_State *L) { 150 if (L->stack == NULL) 151 return; /* stack not completely built yet */ 152 L->ci = &L->base_ci; /* free the entire 'ci' list */ 153 luaE_freeCI(L); 154 luaM_freearray(L, L->stack, L->stacksize); /* free stack array */ 155 } 156 157 158 /* 159 ** Create registry table and its predefined values 160 */ 161 static void init_registry (lua_State *L, global_State *g) { 162 TValue mt; 163 /* create registry */ 164 Table *registry = luaH_new(L); 165 sethvalue(L, &g->l_registry, registry); 166 luaH_resize(L, registry, LUA_RIDX_LAST, 0); 167 /* registry[LUA_RIDX_MAINTHREAD] = L */ 168 setthvalue(L, &mt, L); 169 luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &mt); 170 /* registry[LUA_RIDX_GLOBALS] = table of globals */ 171 sethvalue(L, &mt, luaH_new(L)); 172 luaH_setint(L, registry, LUA_RIDX_GLOBALS, &mt); 173 } 174 175 176 /* 177 ** open parts of the state that may cause memory-allocation errors 178 */ 179 static void f_luaopen (lua_State *L, void *ud) { 180 global_State *g = G(L); 181 UNUSED(ud); 182 stack_init(L, L); /* init stack */ 183 init_registry(L, g); 184 luaS_resize(L, MINSTRTABSIZE); /* initial size of string table */ 185 luaT_init(L); 186 luaX_init(L); 187 /* pre-create memory-error message */ 188 g->memerrmsg = luaS_newliteral(L, MEMERRMSG); 189 luaS_fix(g->memerrmsg); /* it should never be collected */ 190 g->gcrunning = 1; /* allow gc */ 191 g->version = lua_version(NULL); 192 luai_userstateopen(L); 193 } 194 195 196 /* 197 ** preinitialize a state with consistent values without allocating 198 ** any memory (to avoid errors) 199 */ 200 static void preinit_state (lua_State *L, global_State *g) { 201 G(L) = g; 202 L->stack = NULL; 203 L->ci = NULL; 204 L->stacksize = 0; 205 L->errorJmp = NULL; 206 L->nCcalls = 0; 207 L->hook = NULL; 208 L->hookmask = 0; 209 L->basehookcount = 0; 210 L->allowhook = 1; 211 resethookcount(L); 212 L->openupval = NULL; 213 L->nny = 1; 214 L->status = LUA_OK; 215 L->errfunc = 0; 216 L->runerror = 0; 217 } 218 219 220 static void close_state (lua_State *L) { 221 global_State *g = G(L); 222 luaF_close(L, L->stack); /* close all upvalues for this thread */ 223 luaC_freeallobjects(L); /* collect all objects */ 224 if (g->version) /* closing a fully built state? */ 225 luai_userstateclose(L); 226 luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size); 227 luaZ_freebuffer(L, &g->buff); 228 freestack(L); 229 lua_assert(gettotalbytes(g) == sizeof(LG)); 230 (*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0); /* free main block */ 231 } 232 233 234 LUA_API lua_State *lua_newthread (lua_State *L) { 235 lua_State *L1; 236 lua_lock(L); 237 luaC_checkGC(L); 238 L1 = &luaC_newobj(L, LUA_TTHREAD, sizeof(LX), NULL, offsetof(LX, l))->th; 239 setthvalue(L, L->top, L1); 240 api_incr_top(L); 241 preinit_state(L1, G(L)); 242 L1->hookmask = L->hookmask; 243 L1->basehookcount = L->basehookcount; 244 L1->hook = L->hook; 245 resethookcount(L1); 246 luai_userstatethread(L, L1); 247 stack_init(L1, L); /* init stack */ 248 lua_unlock(L); 249 return L1; 250 } 251 252 253 void luaE_freethread (lua_State *L, lua_State *L1) { 254 LX *l = fromstate(L1); 255 luaF_close(L1, L1->stack); /* close all upvalues for this thread */ 256 lua_assert(L1->openupval == NULL); 257 luai_userstatefree(L, L1); 258 freestack(L1); 259 luaM_free(L, l); 260 } 261 262 263 LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) { 264 int i; 265 lua_State *L; 266 global_State *g; 267 LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG))); 268 if (l == NULL) return NULL; 269 L = &l->l.l; 270 g = &l->g; 271 L->next = NULL; 272 L->tt = LUA_TTHREAD; 273 g->currentwhite = bit2mask(WHITE0BIT, FIXEDBIT); 274 L->marked = luaC_white(g); 275 g->gckind = KGC_NORMAL; 276 preinit_state(L, g); 277 g->frealloc = f; 278 g->ud = ud; 279 g->mainthread = L; 280 g->seed = makeseed(L); 281 g->uvhead.u.l.prev = &g->uvhead; 282 g->uvhead.u.l.next = &g->uvhead; 283 g->gcrunning = 0; /* no GC while building state */ 284 g->GCestimate = 0; 285 g->strt.size = 0; 286 g->strt.nuse = 0; 287 g->strt.hash = NULL; 288 setnilvalue(&g->l_registry); 289 luaZ_initbuffer(L, &g->buff); 290 g->panic = NULL; 291 g->version = NULL; 292 g->gcstate = GCSpause; 293 g->allgc = NULL; 294 g->finobj = NULL; 295 g->tobefnz = NULL; 296 g->sweepgc = g->sweepfin = NULL; 297 g->gray = g->grayagain = NULL; 298 g->weak = g->ephemeron = g->allweak = NULL; 299 g->totalbytes = sizeof(LG); 300 g->GCdebt = 0; 301 g->gcpause = LUAI_GCPAUSE; 302 g->gcmajorinc = LUAI_GCMAJOR; 303 g->gcstepmul = LUAI_GCMUL; 304 for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL; 305 if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) { 306 /* memory allocation error: free partial state */ 307 close_state(L); 308 L = NULL; 309 } 310 return L; 311 } 312 313 314 LUA_API void lua_close (lua_State *L) { 315 L = G(L)->mainthread; /* only the main thread can be closed */ 316 lua_lock(L); 317 close_state(L); 318 } 319