/* BEGIN CSTYLED */ /* ** $Id: ldo.c,v 2.108.1.3 2013/11/08 18:22:50 roberto Exp $ ** Stack and Call structure of Lua ** See Copyright Notice in lua.h */ #define ldo_c #define LUA_CORE #include #include "lapi.h" #include "ldebug.h" #include "ldo.h" #include "lfunc.h" #include "lgc.h" #include "lmem.h" #include "lobject.h" #include "lopcodes.h" #include "lparser.h" #include "lstate.h" #include "lstring.h" #include "ltable.h" #include "ltm.h" #include "lvm.h" #include "lzio.h" /* Return the number of bytes available on the stack. */ #if defined (_KERNEL) && defined(__linux__) #include static intptr_t stack_remaining(void) { char local; return (intptr_t)(&local - (char *)current->stack); } #elif defined (_KERNEL) && defined(__FreeBSD__) #include static intptr_t stack_remaining(void) { char local; return (intptr_t)(&local - (char *)curthread->td_kstack); } #else static intptr_t stack_remaining(void) { return INTPTR_MAX; } #endif /* ** {====================================================== ** Error-recovery functions ** ======================================================= */ /* ** LUAI_THROW/LUAI_TRY define how Lua does exception handling. By ** default, Lua handles errors with exceptions when compiling as ** C++ code, with _longjmp/_setjmp when asked to use them, and with ** longjmp/setjmp otherwise. */ #if !defined(LUAI_THROW) #ifdef _KERNEL #if defined(__i386__) #define JMP_BUF_CNT 6 #elif defined(__x86_64__) #define JMP_BUF_CNT 8 #elif defined(__sparc__) && defined(__arch64__) #define JMP_BUF_CNT 6 #elif defined(__powerpc__) #define JMP_BUF_CNT 26 #elif defined(__aarch64__) #define JMP_BUF_CNT 64 #elif defined(__arm__) #define JMP_BUF_CNT 65 #elif defined(__mips__) #define JMP_BUF_CNT 12 #elif defined(__s390x__) #define JMP_BUF_CNT 18 #else #define JMP_BUF_CNT 1 #endif typedef struct _label_t { long long unsigned val[JMP_BUF_CNT]; } label_t; int setjmp(label_t *) __attribute__ ((__nothrow__)); extern void longjmp(label_t *) __attribute__((__noreturn__)); #define LUAI_THROW(L,c) longjmp(&(c)->b) #define LUAI_TRY(L,c,a) if (setjmp(&(c)->b) == 0) { a } #define luai_jmpbuf label_t /* unsupported archs will build but not be able to run lua programs */ #if JMP_BUF_CNT == 1 int setjmp (label_t *buf) { return 1; } void longjmp (label_t * buf) { for (;;); } #endif #else /* _KERNEL */ #if defined(__cplusplus) && !defined(LUA_USE_LONGJMP) /* C++ exceptions */ #define LUAI_THROW(L,c) throw(c) #define LUAI_TRY(L,c,a) \ try { a } catch(...) { if ((c)->status == 0) (c)->status = -1; } #define luai_jmpbuf int /* dummy variable */ #elif defined(LUA_USE_ULONGJMP) /* in Unix, try _longjmp/_setjmp (more efficient) */ #define LUAI_THROW(L,c) _longjmp((c)->b, 1) #define LUAI_TRY(L,c,a) if (_setjmp((c)->b) == 0) { a } #define luai_jmpbuf jmp_buf #else /* default handling with long jumps */ #define LUAI_THROW(L,c) longjmp((c)->b, 1) #define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a } #define luai_jmpbuf jmp_buf #endif #endif /* _KERNEL */ #endif /* LUAI_THROW */ /* chain list of long jump buffers */ struct lua_longjmp { struct lua_longjmp *previous; luai_jmpbuf b; volatile int status; /* error code */ }; static void seterrorobj (lua_State *L, int errcode, StkId oldtop) { switch (errcode) { case LUA_ERRMEM: { /* memory error? */ setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */ break; } case LUA_ERRERR: { setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling")); break; } default: { setobjs2s(L, oldtop, L->top - 1); /* error message on current top */ break; } } L->top = oldtop + 1; } l_noret luaD_throw (lua_State *L, int errcode) { if (L->errorJmp) { /* thread has an error handler? */ L->errorJmp->status = errcode; /* set status */ LUAI_THROW(L, L->errorJmp); /* jump to it */ } else { /* thread has no error handler */ L->status = cast_byte(errcode); /* mark it as dead */ if (G(L)->mainthread->errorJmp) { /* main thread has a handler? */ setobjs2s(L, G(L)->mainthread->top++, L->top - 1); /* copy error obj. */ luaD_throw(G(L)->mainthread, errcode); /* re-throw in main thread */ } else { /* no handler at all; abort */ if (G(L)->panic) { /* panic function? */ lua_unlock(L); G(L)->panic(L); /* call it (last chance to jump out) */ } panic("no error handler"); } } } int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) { unsigned short oldnCcalls = L->nCcalls; struct lua_longjmp lj; lj.status = LUA_OK; lj.previous = L->errorJmp; /* chain new error handler */ // cppcheck-suppress autoVariables L->errorJmp = &lj; LUAI_TRY(L, &lj, (*f)(L, ud); ); L->errorJmp = lj.previous; /* restore old error handler */ L->nCcalls = oldnCcalls; return lj.status; } /* }====================================================== */ static void correctstack (lua_State *L, TValue *oldstack) { CallInfo *ci; GCObject *up; L->top = (L->top - oldstack) + L->stack; for (up = L->openupval; up != NULL; up = up->gch.next) gco2uv(up)->v = (gco2uv(up)->v - oldstack) + L->stack; for (ci = L->ci; ci != NULL; ci = ci->previous) { ci->top = (ci->top - oldstack) + L->stack; ci->func = (ci->func - oldstack) + L->stack; if (isLua(ci)) ci->u.l.base = (ci->u.l.base - oldstack) + L->stack; } } /* some space for error handling */ #define ERRORSTACKSIZE (LUAI_MAXSTACK + 200) void luaD_reallocstack (lua_State *L, int newsize) { TValue *oldstack = L->stack; int lim = L->stacksize; lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE); lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK); luaM_reallocvector(L, L->stack, L->stacksize, newsize, TValue); for (; lim < newsize; lim++) setnilvalue(L->stack + lim); /* erase new segment */ L->stacksize = newsize; L->stack_last = L->stack + newsize - EXTRA_STACK; correctstack(L, oldstack); } void luaD_growstack (lua_State *L, int n) { int size = L->stacksize; if (size > LUAI_MAXSTACK) /* error after extra size? */ luaD_throw(L, LUA_ERRERR); else { int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK; int newsize = 2 * size; if (newsize > LUAI_MAXSTACK) newsize = LUAI_MAXSTACK; if (newsize < needed) newsize = needed; if (newsize > LUAI_MAXSTACK) { /* stack overflow? */ luaD_reallocstack(L, ERRORSTACKSIZE); luaG_runerror(L, "stack overflow"); } else luaD_reallocstack(L, newsize); } } static int stackinuse (lua_State *L) { CallInfo *ci; StkId lim = L->top; for (ci = L->ci; ci != NULL; ci = ci->previous) { lua_assert(ci->top <= L->stack_last); if (lim < ci->top) lim = ci->top; } return cast_int(lim - L->stack) + 1; /* part of stack in use */ } void luaD_shrinkstack (lua_State *L) { int inuse = stackinuse(L); int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK; if (goodsize > LUAI_MAXSTACK) goodsize = LUAI_MAXSTACK; if (inuse > LUAI_MAXSTACK || /* handling stack overflow? */ goodsize >= L->stacksize) /* would grow instead of shrink? */ condmovestack(L); /* don't change stack (change only for debugging) */ else luaD_reallocstack(L, goodsize); /* shrink it */ } void luaD_hook (lua_State *L, int event, int line) { lua_Hook hook = L->hook; if (hook && L->allowhook) { CallInfo *ci = L->ci; ptrdiff_t top = savestack(L, L->top); ptrdiff_t ci_top = savestack(L, ci->top); lua_Debug ar; ar.event = event; ar.currentline = line; ar.i_ci = ci; luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ ci->top = L->top + LUA_MINSTACK; lua_assert(ci->top <= L->stack_last); L->allowhook = 0; /* cannot call hooks inside a hook */ ci->callstatus |= CIST_HOOKED; lua_unlock(L); (*hook)(L, &ar); lua_lock(L); lua_assert(!L->allowhook); L->allowhook = 1; ci->top = restorestack(L, ci_top); L->top = restorestack(L, top); ci->callstatus &= ~CIST_HOOKED; } } static void callhook (lua_State *L, CallInfo *ci) { int hook = LUA_HOOKCALL; ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */ if (isLua(ci->previous) && GET_OPCODE(*(ci->previous->u.l.savedpc - 1)) == OP_TAILCALL) { ci->callstatus |= CIST_TAIL; hook = LUA_HOOKTAILCALL; } luaD_hook(L, hook, -1); ci->u.l.savedpc--; /* correct 'pc' */ } static StkId adjust_varargs (lua_State *L, Proto *p, int actual) { int i; int nfixargs = p->numparams; StkId base, fixed; lua_assert(actual >= nfixargs); /* move fixed parameters to final position */ luaD_checkstack(L, p->maxstacksize); /* check again for new 'base' */ fixed = L->top - actual; /* first fixed argument */ base = L->top; /* final position of first argument */ for (i=0; itop++, fixed + i); setnilvalue(fixed + i); } return base; } static StkId tryfuncTM (lua_State *L, StkId func) { const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL); StkId p; ptrdiff_t funcr = savestack(L, func); if (!ttisfunction(tm)) luaG_typeerror(L, func, "call"); /* Open a hole inside the stack at `func' */ for (p = L->top; p > func; p--) setobjs2s(L, p, p-1); incr_top(L); func = restorestack(L, funcr); /* previous call may change stack */ setobj2s(L, func, tm); /* tag method is the new function to be called */ return func; } #define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L))) /* ** returns true if function has been executed (C function) */ int luaD_precall (lua_State *L, StkId func, int nresults) { lua_CFunction f; CallInfo *ci; int n; /* number of arguments (Lua) or returns (C) */ ptrdiff_t funcr = savestack(L, func); switch (ttype(func)) { case LUA_TLCF: /* light C function */ f = fvalue(func); goto Cfunc; case LUA_TCCL: { /* C closure */ f = clCvalue(func)->f; Cfunc: luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ ci = next_ci(L); /* now 'enter' new function */ ci->nresults = nresults; ci->func = restorestack(L, funcr); ci->top = L->top + LUA_MINSTACK; lua_assert(ci->top <= L->stack_last); ci->callstatus = 0; luaC_checkGC(L); /* stack grow uses memory */ if (L->hookmask & LUA_MASKCALL) luaD_hook(L, LUA_HOOKCALL, -1); lua_unlock(L); n = (*f)(L); /* do the actual call */ lua_lock(L); api_checknelems(L, n); luaD_poscall(L, L->top - n); return 1; } case LUA_TLCL: { /* Lua function: prepare its call */ StkId base; Proto *p = clLvalue(func)->p; n = cast_int(L->top - func) - 1; /* number of real arguments */ luaD_checkstack(L, p->maxstacksize); for (; n < p->numparams; n++) setnilvalue(L->top++); /* complete missing arguments */ if (!p->is_vararg) { func = restorestack(L, funcr); base = func + 1; } else { base = adjust_varargs(L, p, n); func = restorestack(L, funcr); /* previous call can change stack */ } ci = next_ci(L); /* now 'enter' new function */ ci->nresults = nresults; ci->func = func; ci->u.l.base = base; ci->top = base + p->maxstacksize; lua_assert(ci->top <= L->stack_last); ci->u.l.savedpc = p->code; /* starting point */ ci->callstatus = CIST_LUA; L->top = ci->top; luaC_checkGC(L); /* stack grow uses memory */ if (L->hookmask & LUA_MASKCALL) callhook(L, ci); return 0; } default: { /* not a function */ func = tryfuncTM(L, func); /* retry with 'function' tag method */ return luaD_precall(L, func, nresults); /* now it must be a function */ } } } int luaD_poscall (lua_State *L, StkId firstResult) { StkId res; int wanted, i; CallInfo *ci = L->ci; if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) { if (L->hookmask & LUA_MASKRET) { ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */ luaD_hook(L, LUA_HOOKRET, -1); firstResult = restorestack(L, fr); } L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */ } res = ci->func; /* res == final position of 1st result */ wanted = ci->nresults; L->ci = ci = ci->previous; /* back to caller */ /* move results to correct place */ for (i = wanted; i != 0 && firstResult < L->top; i--) setobjs2s(L, res++, firstResult++); while (i-- > 0) setnilvalue(res++); L->top = res; return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */ } /* ** Call a function (C or Lua). The function to be called is at *func. ** The arguments are on the stack, right after the function. ** When returns, all the results are on the stack, starting at the original ** function position. */ void luaD_call (lua_State *L, StkId func, int nResults, int allowyield) { if (++L->nCcalls >= LUAI_MAXCCALLS) { if (L->nCcalls == LUAI_MAXCCALLS) luaG_runerror(L, "C stack overflow"); else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) luaD_throw(L, LUA_ERRERR); /* error while handling stack error */ } intptr_t remaining = stack_remaining(); if (L->runerror == 0 && remaining < LUAI_MINCSTACK) luaG_runerror(L, "C stack overflow"); if (L->runerror != 0 && remaining < LUAI_MINCSTACK / 2) luaD_throw(L, LUA_ERRERR); /* error while handling stack error */ if (!allowyield) L->nny++; if (!luaD_precall(L, func, nResults)) /* is a Lua function? */ luaV_execute(L); /* call it */ if (!allowyield) L->nny--; L->nCcalls--; } static void finishCcall (lua_State *L) { CallInfo *ci = L->ci; int n; lua_assert(ci->u.c.k != NULL); /* must have a continuation */ lua_assert(L->nny == 0); if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */ ci->callstatus &= ~CIST_YPCALL; /* finish 'lua_pcall' */ L->errfunc = ci->u.c.old_errfunc; } /* finish 'lua_callk'/'lua_pcall' */ adjustresults(L, ci->nresults); /* call continuation function */ if (!(ci->callstatus & CIST_STAT)) /* no call status? */ ci->u.c.status = LUA_YIELD; /* 'default' status */ lua_assert(ci->u.c.status != LUA_OK); ci->callstatus = (ci->callstatus & ~(CIST_YPCALL | CIST_STAT)) | CIST_YIELDED; lua_unlock(L); n = (*ci->u.c.k)(L); lua_lock(L); api_checknelems(L, n); /* finish 'luaD_precall' */ luaD_poscall(L, L->top - n); } static void unroll (lua_State *L, void *ud) { UNUSED(ud); for (;;) { if (L->ci == &L->base_ci) /* stack is empty? */ return; /* coroutine finished normally */ if (!isLua(L->ci)) /* C function? */ finishCcall(L); else { /* Lua function */ luaV_finishOp(L); /* finish interrupted instruction */ luaV_execute(L); /* execute down to higher C 'boundary' */ } } } /* ** check whether thread has a suspended protected call */ static CallInfo *findpcall (lua_State *L) { CallInfo *ci; for (ci = L->ci; ci != NULL; ci = ci->previous) { /* search for a pcall */ if (ci->callstatus & CIST_YPCALL) return ci; } return NULL; /* no pending pcall */ } static int recover (lua_State *L, int status) { StkId oldtop; CallInfo *ci = findpcall(L); if (ci == NULL) return 0; /* no recovery point */ /* "finish" luaD_pcall */ oldtop = restorestack(L, ci->extra); luaF_close(L, oldtop); seterrorobj(L, status, oldtop); L->ci = ci; L->allowhook = ci->u.c.old_allowhook; L->nny = 0; /* should be zero to be yieldable */ luaD_shrinkstack(L); L->errfunc = ci->u.c.old_errfunc; ci->callstatus |= CIST_STAT; /* call has error status */ ci->u.c.status = status; /* (here it is) */ return 1; /* continue running the coroutine */ } /* ** signal an error in the call to 'resume', not in the execution of the ** coroutine itself. (Such errors should not be handled by any coroutine ** error handler and should not kill the coroutine.) */ static l_noret resume_error (lua_State *L, const char *msg, StkId firstArg) { L->top = firstArg; /* remove args from the stack */ setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */ api_incr_top(L); luaD_throw(L, -1); /* jump back to 'lua_resume' */ } /* ** do the work for 'lua_resume' in protected mode */ static void resume_cb (lua_State *L, void *ud) { int nCcalls = L->nCcalls; StkId firstArg = cast(StkId, ud); CallInfo *ci = L->ci; if (nCcalls >= LUAI_MAXCCALLS) resume_error(L, "C stack overflow", firstArg); if (L->status == LUA_OK) { /* may be starting a coroutine */ if (ci != &L->base_ci) /* not in base level? */ resume_error(L, "cannot resume non-suspended coroutine", firstArg); /* coroutine is in base level; start running it */ if (!luaD_precall(L, firstArg - 1, LUA_MULTRET)) /* Lua function? */ luaV_execute(L); /* call it */ } else if (L->status != LUA_YIELD) resume_error(L, "cannot resume dead coroutine", firstArg); else { /* resuming from previous yield */ L->status = LUA_OK; ci->func = restorestack(L, ci->extra); if (isLua(ci)) /* yielded inside a hook? */ luaV_execute(L); /* just continue running Lua code */ else { /* 'common' yield */ if (ci->u.c.k != NULL) { /* does it have a continuation? */ int n; ci->u.c.status = LUA_YIELD; /* 'default' status */ ci->callstatus |= CIST_YIELDED; lua_unlock(L); n = (*ci->u.c.k)(L); /* call continuation */ lua_lock(L); api_checknelems(L, n); firstArg = L->top - n; /* yield results come from continuation */ } luaD_poscall(L, firstArg); /* finish 'luaD_precall' */ } unroll(L, NULL); } lua_assert(nCcalls == L->nCcalls); } LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) { int status; int oldnny = L->nny; /* save 'nny' */ lua_lock(L); luai_userstateresume(L, nargs); L->nCcalls = (from) ? from->nCcalls + 1 : 1; L->nny = 0; /* allow yields */ api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs); status = luaD_rawrunprotected(L, resume_cb, L->top - nargs); if (status == -1) /* error calling 'lua_resume'? */ status = LUA_ERRRUN; else { /* yield or regular error */ while (status != LUA_OK && status != LUA_YIELD) { /* error? */ if (recover(L, status)) /* recover point? */ status = luaD_rawrunprotected(L, unroll, NULL); /* run continuation */ else { /* unrecoverable error */ L->status = cast_byte(status); /* mark thread as `dead' */ seterrorobj(L, status, L->top); L->ci->top = L->top; break; } } lua_assert(status == L->status); } L->nny = oldnny; /* restore 'nny' */ L->nCcalls--; lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0)); lua_unlock(L); return status; } LUA_API int lua_yieldk (lua_State *L, int nresults, int ctx, lua_CFunction k) { CallInfo *ci = L->ci; luai_userstateyield(L, nresults); lua_lock(L); api_checknelems(L, nresults); if (L->nny > 0) { if (L != G(L)->mainthread) luaG_runerror(L, "attempt to yield across a C-call boundary"); else luaG_runerror(L, "attempt to yield from outside a coroutine"); } L->status = LUA_YIELD; ci->extra = savestack(L, ci->func); /* save current 'func' */ if (isLua(ci)) { /* inside a hook? */ api_check(L, k == NULL, "hooks cannot continue after yielding"); } else { if ((ci->u.c.k = k) != NULL) /* is there a continuation? */ ci->u.c.ctx = ctx; /* save context */ ci->func = L->top - nresults - 1; /* protect stack below results */ luaD_throw(L, LUA_YIELD); } lua_assert(ci->callstatus & CIST_HOOKED); /* must be inside a hook */ lua_unlock(L); return 0; /* return to 'luaD_hook' */ } int luaD_pcall (lua_State *L, Pfunc func, void *u, ptrdiff_t old_top, ptrdiff_t ef) { int status; CallInfo *old_ci = L->ci; lu_byte old_allowhooks = L->allowhook; unsigned short old_nny = L->nny; ptrdiff_t old_errfunc = L->errfunc; L->errfunc = ef; status = luaD_rawrunprotected(L, func, u); if (status != LUA_OK) { /* an error occurred? */ StkId oldtop = restorestack(L, old_top); luaF_close(L, oldtop); /* close possible pending closures */ seterrorobj(L, status, oldtop); L->ci = old_ci; L->allowhook = old_allowhooks; L->nny = old_nny; luaD_shrinkstack(L); } L->errfunc = old_errfunc; return status; } /* ** Execute a protected parser. */ struct SParser { /* data to `f_parser' */ ZIO *z; Mbuffer buff; /* dynamic structure used by the scanner */ Dyndata dyd; /* dynamic structures used by the parser */ const char *mode; const char *name; }; static void checkmode (lua_State *L, const char *mode, const char *x) { if (mode && strchr(mode, x[0]) == NULL) { luaO_pushfstring(L, "attempt to load a %s chunk (mode is " LUA_QS ")", x, mode); luaD_throw(L, LUA_ERRSYNTAX); } } static void f_parser (lua_State *L, void *ud) { int i; Closure *cl; struct SParser *p = cast(struct SParser *, ud); int c = zgetc(p->z); /* read first character */ lua_assert(c != LUA_SIGNATURE[0]); /* binary not supported */ checkmode(L, p->mode, "text"); cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c); lua_assert(cl->l.nupvalues == cl->l.p->sizeupvalues); for (i = 0; i < cl->l.nupvalues; i++) { /* initialize upvalues */ UpVal *up = luaF_newupval(L); cl->l.upvals[i] = up; luaC_objbarrier(L, cl, up); } } int luaD_protectedparser (lua_State *L, ZIO *z, const char *name, const char *mode) { struct SParser p; int status; L->nny++; /* cannot yield during parsing */ p.z = z; p.name = name; p.mode = mode; p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0; p.dyd.gt.arr = NULL; p.dyd.gt.size = 0; p.dyd.label.arr = NULL; p.dyd.label.size = 0; luaZ_initbuffer(L, &p.buff); status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc); luaZ_freebuffer(L, &p.buff); luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size); luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size); luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size); L->nny--; return status; } /* END CSTYLED */