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Member "memcached-1.6.15/vendor/lua/src/lstate.c" (1 Oct 2021, 11150 Bytes) of package /linux/www/memcached-1.6.15.tar.gz:


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    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 */
   35 typedef 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 */
   44 typedef 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 
   71 static 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 */
   89 void 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 
   99 LUA_API int lua_setcstacklimit (lua_State *L, unsigned int limit) {
  100   UNUSED(L); UNUSED(limit);
  101   return LUAI_MAXCCALLS;  /* warning?? */
  102 }
  103 
  104 
  105 CallInfo *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 */
  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     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 */
  138 void 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 */
  165 void 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_throw(L, LUA_ERRERR);  /* error while handing stack error */
  170 }
  171 
  172 
  173 LUAI_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 
  180 static void stack_init (lua_State *L1, lua_State *L) {
  181   int i; CallInfo *ci;
  182   /* initialize stack array */
  183   L1->stack = luaM_newvector(L, BASIC_STACK_SIZE + EXTRA_STACK, StackValue);
  184   L1->tbclist = L1->stack;
  185   for (i = 0; i < BASIC_STACK_SIZE + EXTRA_STACK; i++)
  186     setnilvalue(s2v(L1->stack + i));  /* erase new stack */
  187   L1->top = L1->stack;
  188   L1->stack_last = L1->stack + 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 = L1->top;
  194   ci->u.c.k = NULL;
  195   ci->nresults = 0;
  196   setnilvalue(s2v(L1->top));  /* 'function' entry for this 'ci' */
  197   L1->top++;
  198   ci->top = L1->top + LUA_MINSTACK;
  199   L1->ci = ci;
  200 }
  201 
  202 
  203 static void freestack (lua_State *L) {
  204   if (L->stack == NULL)
  205     return;  /* stack not completely built yet */
  206   L->ci = &L->base_ci;  /* free the entire 'ci' list */
  207   luaE_freeCI(L);
  208   lua_assert(L->nci == 0);
  209   luaM_freearray(L, L->stack, stacksize(L) + EXTRA_STACK);  /* free stack */
  210 }
  211 
  212 
  213 /*
  214 ** Create registry table and its predefined values
  215 */
  216 static 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, &registry->array[LUA_RIDX_MAINTHREAD - 1], L);
  223   /* registry[LUA_RIDX_GLOBALS] = new table (table of globals) */
  224   sethvalue(L, &registry->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 */
  231 static 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->gcrunning = 1;  /* 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 */
  249 static void preinit_thread (lua_State *L, global_State *g) {
  250   G(L) = g;
  251   L->stack = 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 
  269 static 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);  /* jucst collect its objects */
  273   else {  /* closing a fully built state */
  274     luaD_closeprotected(L, 1, LUA_OK);  /* close all upvalues */
  275     luaC_freeallobjects(L);  /* collect all objects */
  276     luai_userstateclose(L);
  277   }
  278   luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size);
  279   freestack(L);
  280   lua_assert(gettotalbytes(g) == sizeof(LG));
  281   (*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0);  /* free main block */
  282 }
  283 
  284 
  285 LUA_API lua_State *lua_newthread (lua_State *L) {
  286   global_State *g;
  287   lua_State *L1;
  288   lua_lock(L);
  289   g = G(L);
  290   luaC_checkGC(L);
  291   /* create new thread */
  292   L1 = &cast(LX *, luaM_newobject(L, LUA_TTHREAD, sizeof(LX)))->l;
  293   L1->marked = luaC_white(g);
  294   L1->tt = LUA_VTHREAD;
  295   /* link it on list 'allgc' */
  296   L1->next = g->allgc;
  297   g->allgc = obj2gco(L1);
  298   /* anchor it on L stack */
  299   setthvalue2s(L, L->top, L1);
  300   api_incr_top(L);
  301   preinit_thread(L1, g);
  302   L1->hookmask = L->hookmask;
  303   L1->basehookcount = L->basehookcount;
  304   L1->hook = L->hook;
  305   resethookcount(L1);
  306   /* initialize L1 extra space */
  307   memcpy(lua_getextraspace(L1), lua_getextraspace(g->mainthread),
  308          LUA_EXTRASPACE);
  309   luai_userstatethread(L, L1);
  310   stack_init(L1, L);  /* init stack */
  311   lua_unlock(L);
  312   return L1;
  313 }
  314 
  315 
  316 void luaE_freethread (lua_State *L, lua_State *L1) {
  317   LX *l = fromstate(L1);
  318   luaF_closeupval(L1, L1->stack);  /* close all upvalues */
  319   lua_assert(L1->openupval == NULL);
  320   luai_userstatefree(L, L1);
  321   freestack(L1);
  322   luaM_free(L, l);
  323 }
  324 
  325 
  326 int luaE_resetthread (lua_State *L, int status) {
  327   CallInfo *ci = L->ci = &L->base_ci;  /* unwind CallInfo list */
  328   setnilvalue(s2v(L->stack));  /* 'function' entry for basic 'ci' */
  329   ci->func = L->stack;
  330   ci->callstatus = CIST_C;
  331   if (status == LUA_YIELD)
  332     status = LUA_OK;
  333   status = luaD_closeprotected(L, 1, status);
  334   if (status != LUA_OK)  /* errors? */
  335     luaD_seterrorobj(L, status, L->stack + 1);
  336   else
  337     L->top = L->stack + 1;
  338   ci->top = L->top + LUA_MINSTACK;
  339   L->status = cast_byte(status);
  340   luaD_reallocstack(L, cast_int(ci->top - L->stack), 0);
  341   return status;
  342 }
  343 
  344 
  345 LUA_API int lua_resetthread (lua_State *L) {
  346   int status;
  347   lua_lock(L);
  348   status = luaE_resetthread(L, L->status);
  349   lua_unlock(L);
  350   return status;
  351 }
  352 
  353 
  354 LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
  355   int i;
  356   lua_State *L;
  357   global_State *g;
  358   LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG)));
  359   if (l == NULL) return NULL;
  360   L = &l->l.l;
  361   g = &l->g;
  362   L->tt = LUA_VTHREAD;
  363   g->currentwhite = bitmask(WHITE0BIT);
  364   L->marked = luaC_white(g);
  365   preinit_thread(L, g);
  366   g->allgc = obj2gco(L);  /* by now, only object is the main thread */
  367   L->next = NULL;
  368   incnny(L);  /* main thread is always non yieldable */
  369   g->frealloc = f;
  370   g->ud = ud;
  371   g->warnf = NULL;
  372   g->ud_warn = NULL;
  373   g->mainthread = L;
  374   g->seed = luai_makeseed(L);
  375   g->gcrunning = 0;  /* no GC while building state */
  376   g->strt.size = g->strt.nuse = 0;
  377   g->strt.hash = NULL;
  378   setnilvalue(&g->l_registry);
  379   g->panic = NULL;
  380   g->gcstate = GCSpause;
  381   g->gckind = KGC_INC;
  382   g->gcstopem = 0;
  383   g->gcemergency = 0;
  384   g->finobj = g->tobefnz = g->fixedgc = NULL;
  385   g->firstold1 = g->survival = g->old1 = g->reallyold = NULL;
  386   g->finobjsur = g->finobjold1 = g->finobjrold = NULL;
  387   g->sweepgc = NULL;
  388   g->gray = g->grayagain = NULL;
  389   g->weak = g->ephemeron = g->allweak = NULL;
  390   g->twups = NULL;
  391   g->totalbytes = sizeof(LG);
  392   g->GCdebt = 0;
  393   g->lastatomic = 0;
  394   setivalue(&g->nilvalue, 0);  /* to signal that state is not yet built */
  395   setgcparam(g->gcpause, LUAI_GCPAUSE);
  396   setgcparam(g->gcstepmul, LUAI_GCMUL);
  397   g->gcstepsize = LUAI_GCSTEPSIZE;
  398   setgcparam(g->genmajormul, LUAI_GENMAJORMUL);
  399   g->genminormul = LUAI_GENMINORMUL;
  400   for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL;
  401   if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) {
  402     /* memory allocation error: free partial state */
  403     close_state(L);
  404     L = NULL;
  405   }
  406   return L;
  407 }
  408 
  409 
  410 LUA_API void lua_close (lua_State *L) {
  411   lua_lock(L);
  412   L = G(L)->mainthread;  /* only the main thread can be closed */
  413   close_state(L);
  414 }
  415 
  416 
  417 void luaE_warning (lua_State *L, const char *msg, int tocont) {
  418   lua_WarnFunction wf = G(L)->warnf;
  419   if (wf != NULL)
  420     wf(G(L)->ud_warn, msg, tocont);
  421 }
  422 
  423 
  424 /*
  425 ** Generate a warning from an error message
  426 */
  427 void luaE_warnerror (lua_State *L, const char *where) {
  428   TValue *errobj = s2v(L->top - 1);  /* error object */
  429   const char *msg = (ttisstring(errobj))
  430                   ? svalue(errobj)
  431                   : "error object is not a string";
  432   /* produce warning "error in %s (%s)" (where, msg) */
  433   luaE_warning(L, "error in ", 1);
  434   luaE_warning(L, where, 1);
  435   luaE_warning(L, " (", 1);
  436   luaE_warning(L, msg, 1);
  437   luaE_warning(L, ")", 0);
  438 }
  439