1/*
2** $Id: lstate.c $
3** Global State
4** See Copyright Notice in lua.h
5*/
6
7#define lstate_c
8#define LUA_CORE
9
10#include "lprefix.h"
11
12
13#include <stddef.h>
14#include <string.h>
15
16#include "lua.h"
17
18#include "lapi.h"
19#include "ldebug.h"
20#include "ldo.h"
21#include "lfunc.h"
22#include "lgc.h"
23#include "llex.h"
24#include "lmem.h"
25#include "lstate.h"
26#include "lstring.h"
27#include "ltable.h"
28#include "ltm.h"
29
30
31
32/*
33** thread state + extra space
34*/
35typedef struct LX {
36 lu_byte extra_[LUA_EXTRASPACE];
37 lua_State l;
38} LX;
39
40
41/*
42** Main thread combines a thread state and the global state
43*/
44typedef struct LG {
45 LX l;
46 global_State g;
47} LG;
48
49
50
51#define fromstate(L) (cast(LX *, cast(lu_byte *, (L)) - offsetof(LX, l)))
52
53
54/*
55** A macro to create a "random" seed when a state is created;
56** the seed is used to randomize string hashes.
57*/
58#if !defined(luai_makeseed)
59
60#include <time.h>
61
62/*
63** Compute an initial seed with some level of randomness.
64** Rely on Address Space Layout Randomization (if present) and
65** current time.
66*/
67#define addbuff(b,p,e) \
68 { size_t t = cast_sizet(e); \
69 memcpy(b + p, &t, sizeof(t)); p += sizeof(t); }
70
71static unsigned int luai_makeseed (lua_State *L) {
72 char buff[3 * sizeof(size_t)];
73 unsigned int h = cast_uint(time(NULL));
74 int p = 0;
75 addbuff(buff, p, L); /* heap variable */
76 addbuff(buff, p, &h); /* local variable */
77 addbuff(buff, p, &lua_newstate); /* public function */
78 lua_assert(p == sizeof(buff));
79 return luaS_hash(buff, p, h);
80}
81
82#endif
83
84
85/*
86** set GCdebt to a new value keeping the value (totalbytes + GCdebt)
87** invariant (and avoiding underflows in 'totalbytes')
88*/
89void luaE_setdebt (global_State *g, l_mem debt) {
90 l_mem tb = gettotalbytes(g);
91 lua_assert(tb > 0);
92 if (debt < tb - MAX_LMEM)
93 debt = tb - MAX_LMEM; /* will make 'totalbytes == MAX_LMEM' */
94 g->totalbytes = tb - debt;
95 g->GCdebt = debt;
96}
97
98
99LUA_API int lua_setcstacklimit (lua_State *L, unsigned int limit) {
100 UNUSED(L); UNUSED(limit);
101 return LUAI_MAXCCALLS; /* warning?? */
102}
103
104
105CallInfo *luaE_extendCI (lua_State *L) {
106 CallInfo *ci;
107 lua_assert(L->ci->next == NULL);
108 ci = luaM_new(L, CallInfo);
109 lua_assert(L->ci->next == NULL);
110 L->ci->next = ci;
111 ci->previous = L->ci;
112 ci->next = NULL;
113 ci->u.l.trap = 0;
114 L->nci++;
115 return ci;
116}
117
118
119/*
120** free all CallInfo structures not in use by a thread
121*/
122static void 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 L->nci--;
130 }
131}
132
133
134/*
135** free half of the CallInfo structures not in use by a thread,
136** keeping the first one.
137*/
138void luaE_shrinkCI (lua_State *L) {
139 CallInfo *ci = L->ci->next; /* first free CallInfo */
140 CallInfo *next;
141 if (ci == NULL)
142 return; /* no extra elements */
143 while ((next = ci->next) != NULL) { /* two extra elements? */
144 CallInfo *next2 = next->next; /* next's next */
145 ci->next = next2; /* remove next from the list */
146 L->nci--;
147 luaM_free(L, next); /* free next */
148 if (next2 == NULL)
149 break; /* no more elements */
150 else {
151 next2->previous = ci;
152 ci = next2; /* continue */
153 }
154 }
155}
156
157
158/*
159** Called when 'getCcalls(L)' larger or equal to LUAI_MAXCCALLS.
160** If equal, raises an overflow error. If value is larger than
161** LUAI_MAXCCALLS (which means it is handling an overflow) but
162** not much larger, does not report an error (to allow overflow
163** handling to work).
164*/
165void luaE_checkcstack (lua_State *L) {
166 if (getCcalls(L) == LUAI_MAXCCALLS)
167 luaG_runerror(L, "C stack overflow");
168 else if (getCcalls(L) >= (LUAI_MAXCCALLS / 10 * 11))
169 luaD_errerr(L); /* error while handling stack error */
170}
171
172
173LUAI_FUNC void luaE_incCstack (lua_State *L) {
174 L->nCcalls++;
175 if (l_unlikely(getCcalls(L) >= LUAI_MAXCCALLS))
176 luaE_checkcstack(L);
177}
178
179
180static void stack_init (lua_State *L1, lua_State *L) {
181 int i; CallInfo *ci;
182 /* initialize stack array */
183 L1->stack.p = luaM_newvector(L, BASIC_STACK_SIZE + EXTRA_STACK, StackValue);
184 L1->tbclist.p = L1->stack.p;
185 for (i = 0; i < BASIC_STACK_SIZE + EXTRA_STACK; i++)
186 setnilvalue(s2v(L1->stack.p + i)); /* erase new stack */
187 L1->top.p = L1->stack.p;
188 L1->stack_last.p = L1->stack.p + BASIC_STACK_SIZE;
189 /* initialize first ci */
190 ci = &L1->base_ci;
191 ci->next = ci->previous = NULL;
192 ci->callstatus = CIST_C;
193 ci->func.p = L1->top.p;
194 ci->u.c.k = NULL;
195 ci->nresults = 0;
196 setnilvalue(s2v(L1->top.p)); /* 'function' entry for this 'ci' */
197 L1->top.p++;
198 ci->top.p = L1->top.p + LUA_MINSTACK;
199 L1->ci = ci;
200}
201
202
203static void freestack (lua_State *L) {
204 if (L->stack.p == NULL)
205 return; /* stack not completely built yet */
206 L->ci = &L->base_ci; /* free the entire 'ci' list */
207 freeCI(L);
208 lua_assert(L->nci == 0);
209 luaM_freearray(L, L->stack.p, stacksize(L) + EXTRA_STACK); /* free stack */
210}
211
212
213/*
214** Create registry table and its predefined values
215*/
216static void init_registry (lua_State *L, global_State *g) {
217 /* create registry */
218 Table *registry = luaH_new(L);
219 sethvalue(L, &g->l_registry, registry);
220 luaH_resize(L, registry, LUA_RIDX_LAST, 0);
221 /* registry[LUA_RIDX_MAINTHREAD] = L */
222 setthvalue(L, ®istry->array[LUA_RIDX_MAINTHREAD - 1], L);
223 /* registry[LUA_RIDX_GLOBALS] = new table (table of globals) */
224 sethvalue(L, ®istry->array[LUA_RIDX_GLOBALS - 1], luaH_new(L));
225}
226
227
228/*
229** open parts of the state that may cause memory-allocation errors.
230*/
231static void f_luaopen (lua_State *L, void *ud) {
232 global_State *g = G(L);
233 UNUSED(ud);
234 stack_init(L, L); /* init stack */
235 init_registry(L, g);
236 luaS_init(L);
237 luaT_init(L);
238 luaX_init(L);
239 g->gcstp = 0; /* allow gc */
240 setnilvalue(&g->nilvalue); /* now state is complete */
241 luai_userstateopen(L);
242}
243
244
245/*
246** preinitialize a thread with consistent values without allocating
247** any memory (to avoid errors)
248*/
249static void preinit_thread (lua_State *L, global_State *g) {
250 G(L) = g;
251 L->stack.p = NULL;
252 L->ci = NULL;
253 L->nci = 0;
254 L->twups = L; /* thread has no upvalues */
255 L->nCcalls = 0;
256 L->errorJmp = NULL;
257 L->hook = NULL;
258 L->hookmask = 0;
259 L->basehookcount = 0;
260 L->allowhook = 1;
261 resethookcount(L);
262 L->openupval = NULL;
263 L->status = LUA_OK;
264 L->errfunc = 0;
265 L->oldpc = 0;
266}
267
268
269static void close_state (lua_State *L) {
270 global_State *g = G(L);
271 if (!completestate(g)) /* closing a partially built state? */
272 luaC_freeallobjects(L); /* just collect its objects */
273 else { /* closing a fully built state */
274 L->ci = &L->base_ci; /* unwind CallInfo list */
275 L->errfunc = 0; /* stack unwind can "throw away" the error function */
276 luaD_closeprotected(L, 1, LUA_OK); /* close all upvalues */
277 L->top.p = L->stack.p + 1; /* empty the stack to run finalizers */
278 luaC_freeallobjects(L); /* collect all objects */
279 luai_userstateclose(L);
280 }
281 luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size);
282 freestack(L);
283 lua_assert(gettotalbytes(g) == sizeof(LG));
284 (*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0); /* free main block */
285}
286
287
288LUA_API lua_State *lua_newthread (lua_State *L) {
289 global_State *g = G(L);
290 GCObject *o;
291 lua_State *L1;
292 lua_lock(L);
293 luaC_checkGC(L);
294 /* create new thread */
295 o = luaC_newobjdt(L, LUA_TTHREAD, sizeof(LX), offsetof(LX, l));
296 L1 = gco2th(o);
297 /* anchor it on L stack */
298 setthvalue2s(L, L->top.p, L1);
299 api_incr_top(L);
300 preinit_thread(L1, g);
301 L1->hookmask = L->hookmask;
302 L1->basehookcount = L->basehookcount;
303 L1->hook = L->hook;
304 resethookcount(L1);
305 /* initialize L1 extra space */
306 memcpy(lua_getextraspace(L1), lua_getextraspace(g->mainthread),
307 LUA_EXTRASPACE);
308 luai_userstatethread(L, L1);
309 stack_init(L1, L); /* init stack */
310 lua_unlock(L);
311 return L1;
312}
313
314
315void luaE_freethread (lua_State *L, lua_State *L1) {
316 LX *l = fromstate(L1);
317 luaF_closeupval(L1, L1->stack.p); /* close all upvalues */
318 lua_assert(L1->openupval == NULL);
319 luai_userstatefree(L, L1);
320 freestack(L1);
321 luaM_free(L, l);
322}
323
324
325int luaE_resetthread (lua_State *L, int status) {
326 CallInfo *ci = L->ci = &L->base_ci; /* unwind CallInfo list */
327 setnilvalue(s2v(L->stack.p)); /* 'function' entry for basic 'ci' */
328 ci->func.p = L->stack.p;
329 ci->callstatus = CIST_C;
330 if (status == LUA_YIELD)
331 status = LUA_OK;
332 L->status = LUA_OK; /* so it can run __close metamethods */
333 L->errfunc = 0; /* stack unwind can "throw away" the error function */
334 status = luaD_closeprotected(L, 1, status);
335 if (status != LUA_OK) /* errors? */
336 luaD_seterrorobj(L, status, L->stack.p + 1);
337 else
338 L->top.p = L->stack.p + 1;
339 ci->top.p = L->top.p + LUA_MINSTACK;
340 luaD_reallocstack(L, cast_int(ci->top.p - L->stack.p), 0);
341 return status;
342}
343
344
345LUA_API int lua_closethread (lua_State *L, lua_State *from) {
346 int status;
347 lua_lock(L);
348 L->nCcalls = (from) ? getCcalls(from) : 0;
349 status = luaE_resetthread(L, L->status);
350 lua_unlock(L);
351 return status;
352}
353
354
355/*
356** Deprecated! Use 'lua_closethread' instead.
357*/
358LUA_API int lua_resetthread (lua_State *L) {
359 return lua_closethread(L, NULL);
360}
361
362
363LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
364 int i;
365 lua_State *L;
366 global_State *g;
367 LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG)));
368 if (l == NULL) return NULL;
369 L = &l->l.l;
370 g = &l->g;
371 L->tt = LUA_VTHREAD;
372 g->currentwhite = bitmask(WHITE0BIT);
373 L->marked = luaC_white(g);
374 preinit_thread(L, g);
375 g->allgc = obj2gco(L); /* by now, only object is the main thread */
376 L->next = NULL;
377 incnny(L); /* main thread is always non yieldable */
378 g->frealloc = f;
379 g->ud = ud;
380 g->warnf = NULL;
381 g->ud_warn = NULL;
382 g->mainthread = L;
383 g->seed = luai_makeseed(L);
384 g->gcstp = GCSTPGC; /* no GC while building state */
385 g->strt.size = g->strt.nuse = 0;
386 g->strt.hash = NULL;
387 setnilvalue(&g->l_registry);
388 g->panic = NULL;
389 g->gcstate = GCSpause;
390 g->gckind = KGC_INC;
391 g->gcstopem = 0;
392 g->gcemergency = 0;
393 g->finobj = g->tobefnz = g->fixedgc = NULL;
394 g->firstold1 = g->survival = g->old1 = g->reallyold = NULL;
395 g->finobjsur = g->finobjold1 = g->finobjrold = NULL;
396 g->sweepgc = NULL;
397 g->gray = g->grayagain = NULL;
398 g->weak = g->ephemeron = g->allweak = NULL;
399 g->twups = NULL;
400 g->totalbytes = sizeof(LG);
401 g->GCdebt = 0;
402 g->lastatomic = 0;
403 setivalue(&g->nilvalue, 0); /* to signal that state is not yet built */
404 setgcparam(g->gcpause, LUAI_GCPAUSE);
405 setgcparam(g->gcstepmul, LUAI_GCMUL);
406 g->gcstepsize = LUAI_GCSTEPSIZE;
407 setgcparam(g->genmajormul, LUAI_GENMAJORMUL);
408 g->genminormul = LUAI_GENMINORMUL;
409 for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL;
410 if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) {
411 /* memory allocation error: free partial state */
412 close_state(L);
413 L = NULL;
414 }
415 return L;
416}
417
418
419LUA_API void lua_close (lua_State *L) {
420 lua_lock(L);
421 L = G(L)->mainthread; /* only the main thread can be closed */
422 close_state(L);
423}
424
425
426void luaE_warning (lua_State *L, const char *msg, int tocont) {
427 lua_WarnFunction wf = G(L)->warnf;
428 if (wf != NULL)
429 wf(G(L)->ud_warn, msg, tocont);
430}
431
432
433/*
434** Generate a warning from an error message
435*/
436void luaE_warnerror (lua_State *L, const char *where) {
437 TValue *errobj = s2v(L->top.p - 1); /* error object */
438 const char *msg = (ttisstring(errobj))
439 ? getstr(tsvalue(errobj))
440 : "error object is not a string";
441 /* produce warning "error in %s (%s)" (where, msg) */
442 luaE_warning(L, "error in ", 1);
443 luaE_warning(L, where, 1);
444 luaE_warning(L, " (", 1);
445 luaE_warning(L, msg, 1);
446 luaE_warning(L, ")", 0);
447}
448