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 #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 #ifndef SYSLINUX
51 #include <time.h>
52 #define luai_makeseed() cast(unsigned int, time(NULL))
53 #else
54 #include <sys/times.h>
55 #define luai_makeseed() cast(unsigned int, times(NULL))
56 #endif /* SYSLINUX */
57 #endif
58
59
60
61 /*
62 ** thread state + extra space
63 */
64 typedef struct LX {
65 #if defined(LUAI_EXTRASPACE)
66 char buff[LUAI_EXTRASPACE];
67 #endif
68 lua_State l;
69 } LX;
70
71
72 /*
73 ** Main thread combines a thread state and the global state
74 */
75 typedef struct LG {
76 LX l;
77 global_State g;
78 } LG;
79
80
81
82 #define fromstate(L) (cast(LX *, cast(lu_byte *, (L)) - offsetof(LX, l)))
83
84
85 /*
86 ** Compute an initial seed as random as possible. In ANSI, rely on
87 ** Address Space Layout Randomization (if present) to increase
88 ** randomness..
89 */
90 #define addbuff(b,p,e) \
91 { size_t t = cast(size_t, e); \
92 memcpy(buff + p, &t, sizeof(t)); p += sizeof(t); }
93
makeseed(lua_State * L)94 static unsigned int makeseed (lua_State *L) {
95 char buff[4 * sizeof(size_t)];
96 unsigned int h = luai_makeseed();
97 int p = 0;
98 addbuff(buff, p, L); /* heap variable */
99 addbuff(buff, p, &h); /* local variable */
100 addbuff(buff, p, luaO_nilobject); /* global variable */
101 addbuff(buff, p, &lua_newstate); /* public function */
102 lua_assert(p == sizeof(buff));
103 return luaS_hash(buff, p, h);
104 }
105
106
107 /*
108 ** set GCdebt to a new value keeping the value (totalbytes + GCdebt)
109 ** invariant
110 */
luaE_setdebt(global_State * g,l_mem debt)111 void luaE_setdebt (global_State *g, l_mem debt) {
112 g->totalbytes -= (debt - g->GCdebt);
113 g->GCdebt = debt;
114 }
115
116
luaE_extendCI(lua_State * L)117 CallInfo *luaE_extendCI (lua_State *L) {
118 CallInfo *ci = luaM_new(L, CallInfo);
119 lua_assert(L->ci->next == NULL);
120 L->ci->next = ci;
121 ci->previous = L->ci;
122 ci->next = NULL;
123 return ci;
124 }
125
126
luaE_freeCI(lua_State * L)127 void luaE_freeCI (lua_State *L) {
128 CallInfo *ci = L->ci;
129 CallInfo *next = ci->next;
130 ci->next = NULL;
131 while ((ci = next) != NULL) {
132 next = ci->next;
133 luaM_free(L, ci);
134 }
135 }
136
137
stack_init(lua_State * L1,lua_State * L)138 static void stack_init (lua_State *L1, lua_State *L) {
139 int i; CallInfo *ci;
140 /* initialize stack array */
141 L1->stack = luaM_newvector(L, BASIC_STACK_SIZE, TValue);
142 L1->stacksize = BASIC_STACK_SIZE;
143 for (i = 0; i < BASIC_STACK_SIZE; i++)
144 setnilvalue(L1->stack + i); /* erase new stack */
145 L1->top = L1->stack;
146 L1->stack_last = L1->stack + L1->stacksize - EXTRA_STACK;
147 /* initialize first ci */
148 ci = &L1->base_ci;
149 ci->next = ci->previous = NULL;
150 ci->callstatus = 0;
151 ci->func = L1->top;
152 setnilvalue(L1->top++); /* 'function' entry for this 'ci' */
153 ci->top = L1->top + LUA_MINSTACK;
154 L1->ci = ci;
155 }
156
157
freestack(lua_State * L)158 static void freestack (lua_State *L) {
159 if (L->stack == NULL)
160 return; /* stack not completely built yet */
161 L->ci = &L->base_ci; /* free the entire 'ci' list */
162 luaE_freeCI(L);
163 luaM_freearray(L, L->stack, L->stacksize); /* free stack array */
164 }
165
166
167 /*
168 ** Create registry table and its predefined values
169 */
init_registry(lua_State * L,global_State * g)170 static void init_registry (lua_State *L, global_State *g) {
171 TValue mt;
172 /* create registry */
173 Table *registry = luaH_new(L);
174 sethvalue(L, &g->l_registry, registry);
175 luaH_resize(L, registry, LUA_RIDX_LAST, 0);
176 /* registry[LUA_RIDX_MAINTHREAD] = L */
177 setthvalue(L, &mt, L);
178 luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &mt);
179 /* registry[LUA_RIDX_GLOBALS] = table of globals */
180 sethvalue(L, &mt, luaH_new(L));
181 luaH_setint(L, registry, LUA_RIDX_GLOBALS, &mt);
182 }
183
184
185 /*
186 ** open parts of the state that may cause memory-allocation errors
187 */
f_luaopen(lua_State * L,void * ud)188 static void f_luaopen (lua_State *L, void *ud) {
189 global_State *g = G(L);
190 UNUSED(ud);
191 stack_init(L, L); /* init stack */
192 init_registry(L, g);
193 luaS_resize(L, MINSTRTABSIZE); /* initial size of string table */
194 luaT_init(L);
195 luaX_init(L);
196 /* pre-create memory-error message */
197 g->memerrmsg = luaS_newliteral(L, MEMERRMSG);
198 luaS_fix(g->memerrmsg); /* it should never be collected */
199 g->gcrunning = 1; /* allow gc */
200 g->version = lua_version(NULL);
201 luai_userstateopen(L);
202 }
203
204
205 /*
206 ** preinitialize a state with consistent values without allocating
207 ** any memory (to avoid errors)
208 */
preinit_state(lua_State * L,global_State * g)209 static void preinit_state (lua_State *L, global_State *g) {
210 G(L) = g;
211 L->stack = NULL;
212 L->ci = NULL;
213 L->stacksize = 0;
214 L->errorJmp = NULL;
215 L->nCcalls = 0;
216 L->hook = NULL;
217 L->hookmask = 0;
218 L->basehookcount = 0;
219 L->allowhook = 1;
220 resethookcount(L);
221 L->openupval = NULL;
222 L->nny = 1;
223 L->status = LUA_OK;
224 L->errfunc = 0;
225 }
226
227
close_state(lua_State * L)228 static void close_state (lua_State *L) {
229 global_State *g = G(L);
230 luaF_close(L, L->stack); /* close all upvalues for this thread */
231 luaC_freeallobjects(L); /* collect all objects */
232 if (g->version) /* closing a fully built state? */
233 luai_userstateclose(L);
234 luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size);
235 luaZ_freebuffer(L, &g->buff);
236 freestack(L);
237 lua_assert(gettotalbytes(g) == sizeof(LG));
238 (*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0); /* free main block */
239 }
240
241
lua_newthread(lua_State * L)242 LUA_API lua_State *lua_newthread (lua_State *L) {
243 lua_State *L1;
244 lua_lock(L);
245 luaC_checkGC(L);
246 L1 = &luaC_newobj(L, LUA_TTHREAD, sizeof(LX), NULL, offsetof(LX, l))->th;
247 setthvalue(L, L->top, L1);
248 api_incr_top(L);
249 preinit_state(L1, G(L));
250 L1->hookmask = L->hookmask;
251 L1->basehookcount = L->basehookcount;
252 L1->hook = L->hook;
253 resethookcount(L1);
254 luai_userstatethread(L, L1);
255 stack_init(L1, L); /* init stack */
256 lua_unlock(L);
257 return L1;
258 }
259
260
luaE_freethread(lua_State * L,lua_State * L1)261 void luaE_freethread (lua_State *L, lua_State *L1) {
262 LX *l = fromstate(L1);
263 luaF_close(L1, L1->stack); /* close all upvalues for this thread */
264 lua_assert(L1->openupval == NULL);
265 luai_userstatefree(L, L1);
266 freestack(L1);
267 luaM_free(L, l);
268 }
269
270
lua_newstate(lua_Alloc f,void * ud)271 LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
272 int i;
273 lua_State *L;
274 global_State *g;
275 LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG)));
276 if (l == NULL) return NULL;
277 L = &l->l.l;
278 g = &l->g;
279 L->next = NULL;
280 L->tt = LUA_TTHREAD;
281 g->currentwhite = bit2mask(WHITE0BIT, FIXEDBIT);
282 L->marked = luaC_white(g);
283 g->gckind = KGC_NORMAL;
284 preinit_state(L, g);
285 g->frealloc = f;
286 g->ud = ud;
287 g->mainthread = L;
288 g->seed = makeseed(L);
289 g->uvhead.u.l.prev = &g->uvhead;
290 g->uvhead.u.l.next = &g->uvhead;
291 g->gcrunning = 0; /* no GC while building state */
292 g->GCestimate = 0;
293 g->strt.size = 0;
294 g->strt.nuse = 0;
295 g->strt.hash = NULL;
296 setnilvalue(&g->l_registry);
297 luaZ_initbuffer(L, &g->buff);
298 g->panic = NULL;
299 g->version = NULL;
300 g->gcstate = GCSpause;
301 g->allgc = NULL;
302 g->finobj = NULL;
303 g->tobefnz = NULL;
304 g->sweepgc = g->sweepfin = NULL;
305 g->gray = g->grayagain = NULL;
306 g->weak = g->ephemeron = g->allweak = NULL;
307 g->totalbytes = sizeof(LG);
308 g->GCdebt = 0;
309 g->gcpause = LUAI_GCPAUSE;
310 g->gcmajorinc = LUAI_GCMAJOR;
311 g->gcstepmul = LUAI_GCMUL;
312 for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL;
313 if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) {
314 /* memory allocation error: free partial state */
315 close_state(L);
316 L = NULL;
317 }
318 return L;
319 }
320
321
lua_close(lua_State * L)322 LUA_API void lua_close (lua_State *L) {
323 L = G(L)->mainthread; /* only the main thread can be closed */
324 lua_lock(L);
325 close_state(L);
326 }
327
328
329