1 /*
2 ** $Id: lstate.c,v 2.36.1.2 2008/01/03 15:20:39 roberto Exp $
3 ** Global State
4 ** See Copyright Notice in lua.h
5 */
6 
7 
8 #include <stddef.h>
9 
10 #define lstate_c
11 #define LUA_CORE
12 
13 #include "lua.h"
14 
15 #include "ldebug.h"
16 #include "ldo.h"
17 #include "lfunc.h"
18 #include "lgc.h"
19 #include "llex.h"
20 #include "lmem.h"
21 #include "lstate.h"
22 #include "lstring.h"
23 #include "ltable.h"
24 #include "ltm.h"
25 
26 
27 #define state_size(x)   (sizeof(x) + LUAI_EXTRASPACE)
28 #define fromstate(l)    (cast(lu_byte *, (l)) - LUAI_EXTRASPACE)
29 #define tostate(l)   (cast(lua_State *, cast(lu_byte *, l) + LUAI_EXTRASPACE))
30 
31 
32 /*
33 ** Main thread combines a thread state and the global state
34 */
35 typedef struct LG {
36   lua_State l;
37   global_State g;
38 } LG;
39 
40 
41 
stack_init(lua_State * L1,lua_State * L)42 static void stack_init (lua_State *L1, lua_State *L) {
43   /* initialize CallInfo array */
44   L1->base_ci = luaM_newvector(L, BASIC_CI_SIZE, CallInfo);
45   L1->ci = L1->base_ci;
46   L1->size_ci = BASIC_CI_SIZE;
47   L1->end_ci = L1->base_ci + L1->size_ci - 1;
48   /* initialize stack array */
49   L1->stack = luaM_newvector(L, BASIC_STACK_SIZE + EXTRA_STACK, TValue);
50   L1->stacksize = BASIC_STACK_SIZE + EXTRA_STACK;
51   L1->top = L1->stack;
52   L1->stack_last = L1->stack+(L1->stacksize - EXTRA_STACK)-1;
53   /* initialize first ci */
54   L1->ci->func = L1->top;
55   setnilvalue(L1->top++);  /* `function' entry for this `ci' */
56   L1->base = L1->ci->base = L1->top;
57   L1->ci->top = L1->top + LUA_MINSTACK;
58 }
59 
60 
freestack(lua_State * L,lua_State * L1)61 static void freestack (lua_State *L, lua_State *L1) {
62   luaM_freearray(L, L1->base_ci, L1->size_ci, CallInfo);
63   luaM_freearray(L, L1->stack, L1->stacksize, TValue);
64 }
65 
66 
67 /*
68 ** open parts that may cause memory-allocation errors
69 */
f_luaopen(lua_State * L,void * ud)70 static void f_luaopen (lua_State *L, void *ud) {
71   global_State *g = G(L);
72   UNUSED(ud);
73   stack_init(L, L);  /* init stack */
74   sethvalue(L, gt(L), luaH_new(L, 0, 2));  /* table of globals */
75   sethvalue(L, registry(L), luaH_new(L, 0, 2));  /* registry */
76   luaS_resize(L, MINSTRTABSIZE);  /* initial size of string table */
77   luaT_init(L);
78   luaX_init(L);
79   luaS_fix(luaS_newliteral(L, MEMERRMSG));
80   g->GCthreshold = 4*g->totalbytes;
81 }
82 
83 
preinit_state(lua_State * L,global_State * g)84 static void preinit_state (lua_State *L, global_State *g) {
85   G(L) = g;
86   L->stack = NULL;
87   L->stacksize = 0;
88   L->errorJmp = NULL;
89   L->hook = NULL;
90   L->hookmask = 0;
91   L->basehookcount = 0;
92   L->allowhook = 1;
93   resethookcount(L);
94   L->openupval = NULL;
95   L->size_ci = 0;
96   L->nCcalls = L->baseCcalls = 0;
97   L->status = 0;
98   L->base_ci = L->ci = NULL;
99   L->savedpc = NULL;
100   L->errfunc = 0;
101   setnilvalue(gt(L));
102 }
103 
104 
close_state(lua_State * L)105 static void close_state (lua_State *L) {
106   global_State *g = G(L);
107   luaF_close(L, L->stack);  /* close all upvalues for this thread */
108   luaC_freeall(L);  /* collect all objects */
109   lua_assert(g->rootgc == obj2gco(L));
110   lua_assert(g->strt.nuse == 0);
111   luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size, TString *);
112   luaZ_freebuffer(L, &g->buff);
113   freestack(L, L);
114   lua_assert(g->totalbytes == sizeof(LG));
115   (*g->frealloc)(g->ud, fromstate(L), state_size(LG), 0);
116 }
117 
118 
luaE_newthread(lua_State * L)119 lua_State *luaE_newthread (lua_State *L) {
120   lua_State *L1 = tostate(luaM_malloc(L, state_size(lua_State)));
121   luaC_link(L, obj2gco(L1), LUA_TTHREAD);
122   preinit_state(L1, G(L));
123   stack_init(L1, L);  /* init stack */
124   setobj2n(L, gt(L1), gt(L));  /* share table of globals */
125   L1->hookmask = L->hookmask;
126   L1->basehookcount = L->basehookcount;
127   L1->hook = L->hook;
128   resethookcount(L1);
129   lua_assert(iswhite(obj2gco(L1)));
130   return L1;
131 }
132 
133 
luaE_freethread(lua_State * L,lua_State * L1)134 void luaE_freethread (lua_State *L, lua_State *L1) {
135   luaF_close(L1, L1->stack);  /* close all upvalues for this thread */
136   lua_assert(L1->openupval == NULL);
137   luai_userstatefree(L1);
138   freestack(L, L1);
139   luaM_freemem(L, fromstate(L1), state_size(lua_State));
140 }
141 
142 
lua_newstate(lua_Alloc f,void * ud)143 LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
144   int i;
145   lua_State *L;
146   global_State *g;
147   void *l = (*f)(ud, NULL, 0, state_size(LG));
148   if (l == NULL) return NULL;
149   L = tostate(l);
150   g = &((LG *)L)->g;
151   L->next = NULL;
152   L->tt = LUA_TTHREAD;
153   g->currentwhite = bit2mask(WHITE0BIT, FIXEDBIT);
154   L->marked = luaC_white(g);
155   set2bits(L->marked, FIXEDBIT, SFIXEDBIT);
156   preinit_state(L, g);
157   g->frealloc = f;
158   g->ud = ud;
159   g->mainthread = L;
160   g->uvhead.u.l.prev = &g->uvhead;
161   g->uvhead.u.l.next = &g->uvhead;
162   g->GCthreshold = 0;  /* mark it as unfinished state */
163   g->strt.size = 0;
164   g->strt.nuse = 0;
165   g->strt.hash = NULL;
166   setnilvalue(registry(L));
167   luaZ_initbuffer(L, &g->buff);
168   g->panic = NULL;
169   g->gcstate = GCSpause;
170   g->rootgc = obj2gco(L);
171   g->sweepstrgc = 0;
172   g->sweepgc = &g->rootgc;
173   g->gray = NULL;
174   g->grayagain = NULL;
175   g->weak = NULL;
176   g->tmudata = NULL;
177   g->totalbytes = sizeof(LG);
178   g->gcpause = LUAI_GCPAUSE;
179   g->gcstepmul = LUAI_GCMUL;
180   g->gcdept = 0;
181   for (i=0; i<NUM_TAGS; i++) g->mt[i] = NULL;
182   if (luaD_rawrunprotected(L, f_luaopen, NULL) != 0) {
183     /* memory allocation error: free partial state */
184     close_state(L);
185     L = NULL;
186   }
187   else
188     luai_userstateopen(L);
189   return L;
190 }
191 
192 
callallgcTM(lua_State * L,void * ud)193 static void callallgcTM (lua_State *L, void *ud) {
194   UNUSED(ud);
195   luaC_callGCTM(L);  /* call GC metamethods for all udata */
196 }
197 
198 
lua_close(lua_State * L)199 LUA_API void lua_close (lua_State *L) {
200   L = G(L)->mainthread;  /* only the main thread can be closed */
201   lua_lock(L);
202   luaF_close(L, L->stack);  /* close all upvalues for this thread */
203   luaC_separateudata(L, 1);  /* separate udata that have GC metamethods */
204   L->errfunc = 0;  /* no error function during GC metamethods */
205   do {  /* repeat until no more errors */
206     L->ci = L->base_ci;
207     L->base = L->top = L->ci->base;
208     L->nCcalls = L->baseCcalls = 0;
209   } while (luaD_rawrunprotected(L, callallgcTM, NULL) != 0);
210   lua_assert(G(L)->tmudata == NULL);
211   luai_userstateclose(L);
212   close_state(L);
213 }
214 
215