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
makeseed(lua_State * L)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 */
luaE_setdebt(global_State * g,l_mem debt)106 void luaE_setdebt (global_State *g, l_mem debt) {
107 g->totalbytes -= (debt - g->GCdebt);
108 g->GCdebt = debt;
109 }
110
111
luaE_extendCI(lua_State * L)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
luaE_freeCI(lua_State * L)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
stack_init(lua_State * L1,lua_State * L)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
freestack(lua_State * L)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 */
init_registry(lua_State * L,global_State * g)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 */
f_luaopen(lua_State * L,void * ud)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 */
preinit_state(lua_State * L,global_State * g)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
close_state(lua_State * L)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
lua_newthread(lua_State * L)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
luaE_freethread(lua_State * L,lua_State * L1)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
lua_newstate(lua_Alloc f,void * ud)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
lua_close(lua_State * L)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