commit f76f4cb79d84af4a7be9e0d75553bbe05a3ae90c
parent abb85fc059a5d6427b9dc36edee1619f2c7a1da8
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 15 Jul 2009 14:25:50 -0300
new way to control stack overflow, controling only total size of the stack
Diffstat:
10 files changed, 100 insertions(+), 78 deletions(-)
diff --git a/lapi.c b/lapi.c
@@ -1,5 +1,5 @@
/*
-** $Id: lapi.c,v 2.83 2009/06/18 18:59:18 roberto Exp roberto $
+** $Id: lapi.c,v 2.84 2009/06/19 14:21:23 roberto Exp roberto $
** Lua API
** See Copyright Notice in lua.h
*/
@@ -86,14 +86,15 @@ LUA_API int lua_checkstack (lua_State *L, int size) {
int res = 1;
CallInfo *ci = L->ci;
lua_lock(L);
- if (size > LUAI_MAXCSTACK ||
- (L->top - (ci->func + 1) + size) > LUAI_MAXCSTACK)
- res = 0; /* stack overflow */
- else if (size > 0) {
- luaD_checkstack(L, size);
- if (ci->top < L->top + size)
- ci->top = L->top + size;
+ if (L->stack_last - L->top <= size) { /* need to grow stack? */
+ int inuse = L->top - L->stack + EXTRA_STACK;
+ if (inuse > LUAI_MAXSTACK - size) /* can grow without overflow? */
+ res = 0; /* no */
+ else
+ luaD_growstack(L, size);
}
+ if (res && ci->top < L->top + size)
+ ci->top = L->top + size; /* adjust frame top */
lua_unlock(L);
return res;
}
diff --git a/lauxlib.c b/lauxlib.c
@@ -1,5 +1,5 @@
/*
-** $Id: lauxlib.c,v 1.187 2009/06/18 18:59:58 roberto Exp roberto $
+** $Id: lauxlib.c,v 1.188 2009/06/19 14:21:57 roberto Exp roberto $
** Auxiliary functions for building Lua libraries
** See Copyright Notice in lua.h
*/
@@ -106,9 +106,16 @@ static void pushfuncname (lua_State *L, lua_Debug *ar) {
static int countlevels (lua_State *L) {
lua_Debug ar;
- int level = 1;
- while (lua_getstack(L, level, &ar)) level++;
- return level;
+ int li = 1, le = 1;
+ /* find an upper bound */
+ while (lua_getstack(L, le, &ar)) { li = le; le *= 2; }
+ /* do a binary search */
+ while (li < le) {
+ int m = (li + le)/2;
+ if (lua_getstack(L, m, &ar)) li = m + 1;
+ else le = m;
+ }
+ return le - 1;
}
@@ -263,9 +270,13 @@ LUALIB_API int luaL_checkoption (lua_State *L, int narg, const char *def,
}
-LUALIB_API void luaL_checkstack (lua_State *L, int space, const char *mes) {
- if (!lua_checkstack(L, space))
- luaL_error(L, "stack overflow (%s)", mes);
+LUALIB_API void luaL_checkstack (lua_State *L, int space, const char *msg) {
+ if (!lua_checkstack(L, space)) {
+ if (msg)
+ luaL_error(L, "stack overflow (%s)", msg);
+ else
+ luaL_error(L, "stack overflow");
+ }
}
diff --git a/ldo.c b/ldo.c
@@ -1,5 +1,5 @@
/*
-** $Id: ldo.c,v 2.64 2009/05/21 20:06:11 roberto Exp roberto $
+** $Id: ldo.c,v 2.65 2009/06/01 19:09:26 roberto Exp roberto $
** Stack and Call structure of Lua
** See Copyright Notice in lua.h
*/
@@ -70,12 +70,6 @@ void luaD_seterrorobj (lua_State *L, int errcode, StkId oldtop) {
}
-static void restore_stack_limit (lua_State *L) {
- if (L->nci >= LUAI_MAXCALLS) /* stack overflow? */
- luaE_freeCI(L); /* erase all extras CIs */
-}
-
-
void luaD_throw (lua_State *L, int errcode) {
if (L->errorJmp) { /* thread has an error handler? */
L->errorJmp->status = errcode; /* set status */
@@ -130,25 +124,63 @@ static void correctstack (lua_State *L, TValue *oldstack) {
}
+/* 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;
- int realsize = newsize + 1 + EXTRA_STACK;
- lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK - 1);
- luaM_reallocvector(L, L->stack, L->stacksize, realsize, TValue);
- for (; lim < realsize; lim++)
+ 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 = realsize;
- L->stack_last = L->stack+newsize;
+ L->stacksize = newsize;
+ L->stack_last = L->stack + newsize - EXTRA_STACK;
correctstack(L, oldstack);
}
void luaD_growstack (lua_State *L, int n) {
- if (n <= L->stacksize) /* double size is enough? */
- luaD_reallocstack(L, 2*L->stacksize);
+ int size = L->stacksize;
+ if (size > LUAI_MAXSTACK) /* error after extra size? */
+ luaD_throw(L, LUA_ERRERR);
+ else {
+ int needed = 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, L->stacksize + n);
+ luaD_reallocstack(L, goodsize); /* shrink it */
}
@@ -427,7 +459,7 @@ static int recover (lua_State *L, int status) {
L->ci = ci;
L->allowhook = ci->u.c.old_allowhook;
L->nny = 0; /* should be zero to be yieldable */
- restore_stack_limit(L);
+ 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) */
@@ -499,7 +531,7 @@ int luaD_pcall (lua_State *L, Pfunc func, void *u,
L->ci = old_ci;
L->allowhook = old_allowhooks;
L->nny = old_nny;
- restore_stack_limit(L);
+ luaD_shrinkstack(L);
}
L->errfunc = old_errfunc;
return status;
diff --git a/ldo.h b/ldo.h
@@ -1,5 +1,5 @@
/*
-** $Id: ldo.h,v 2.13 2009/06/08 19:35:59 roberto Exp roberto $
+** $Id: ldo.h,v 2.14 2009/07/08 16:06:51 roberto Exp roberto $
** Stack and Call structure of Lua
** See Copyright Notice in lua.h
*/
@@ -37,6 +37,7 @@ LUAI_FUNC int luaD_poscall (lua_State *L, StkId firstResult);
LUAI_FUNC void luaD_reallocCI (lua_State *L, int newsize);
LUAI_FUNC void luaD_reallocstack (lua_State *L, int newsize);
LUAI_FUNC void luaD_growstack (lua_State *L, int n);
+LUAI_FUNC void luaD_shrinkstack (lua_State *L);
LUAI_FUNC void luaD_throw (lua_State *L, int errcode);
LUAI_FUNC int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud);
diff --git a/llimits.h b/llimits.h
@@ -1,5 +1,5 @@
/*
-** $Id: llimits.h,v 1.71 2009/06/08 19:35:59 roberto Exp roberto $
+** $Id: llimits.h,v 1.72 2009/07/01 16:14:15 roberto Exp roberto $
** Limits, basic types, and some other `installation-dependent' definitions
** See Copyright Notice in lua.h
*/
@@ -122,8 +122,8 @@ typedef lu_int32 Instruction;
#ifndef HARDSTACKTESTS
#define condmovestack(L) ((void)0)
#else
-#define condmovestack(L) /* realloc stack keeping its size */ \
- luaD_reallocstack((L), (L)->stacksize - EXTRA_STACK - 1)
+/* realloc stack keeping its size */
+#define condmovestack(L) luaD_reallocstack((L), (L)->stacksize)
#endif
#endif
diff --git a/lstate.c b/lstate.c
@@ -1,5 +1,5 @@
/*
-** $Id: lstate.c,v 2.55 2009/06/01 19:09:26 roberto Exp roberto $
+** $Id: lstate.c,v 2.56 2009/06/18 18:59:18 roberto Exp roberto $
** Global State
** See Copyright Notice in lua.h
*/
@@ -52,12 +52,6 @@ CallInfo *luaE_extendCI (lua_State *L) {
L->ci->next = ci;
ci->previous = L->ci;
ci->next = NULL;
- if (++L->nci >= LUAI_MAXCALLS) {
- if (L->nci == LUAI_MAXCALLS) /* overflow? */
- luaG_runerror(L, "stack overflow");
- if (L->nci >= LUAI_MAXCALLS + LUAI_EXTRACALLS) /* again? */
- luaD_throw(L, LUA_ERRERR); /* error while handling overflow */
- }
return ci;
}
@@ -69,7 +63,6 @@ void luaE_freeCI (lua_State *L) {
while ((ci = next) != NULL) {
next = ci->next;
luaM_free(L, ci);
- L->nci--;
}
}
@@ -77,12 +70,12 @@ void luaE_freeCI (lua_State *L) {
static void stack_init (lua_State *L1, lua_State *L) {
int i;
/* initialize stack array */
- L1->stack = luaM_newvector(L, BASIC_STACK_SIZE + EXTRA_STACK, TValue);
- L1->stacksize = BASIC_STACK_SIZE + EXTRA_STACK;
- for (i = 0; i < BASIC_STACK_SIZE + EXTRA_STACK; i++)
+ L1->stack = luaM_newvector(L, BASIC_STACK_SIZE, TValue);
+ L1->stacksize = BASIC_STACK_SIZE;
+ for (i = 0; i < BASIC_STACK_SIZE; i++)
setnilvalue(L1->stack + i); /* erase new stack */
L1->top = L1->stack;
- L1->stack_last = L1->stack+(L1->stacksize - EXTRA_STACK)-1;
+ L1->stack_last = L1->stack + L1->stacksize - EXTRA_STACK;
/* initialize first ci */
L1->ci->func = L1->top;
setnilvalue(L1->top++); /* 'function' entry for this 'ci' */
@@ -94,7 +87,6 @@ static void stack_init (lua_State *L1, lua_State *L) {
static void freestack (lua_State *L) {
L->ci = &L->base_ci; /* reset 'ci' list */
luaE_freeCI(L);
- lua_assert(L->nci == 0);
luaM_freearray(L, L->stack, L->stacksize);
}
@@ -131,7 +123,6 @@ static void preinit_state (lua_State *L, global_State *g) {
L->status = LUA_OK;
L->base_ci.next = L->base_ci.previous = NULL;
L->ci = &L->base_ci;
- L->nci = 0;
L->errfunc = 0;
setnilvalue(gt(L));
}
diff --git a/lstate.h b/lstate.h
@@ -1,5 +1,5 @@
/*
-** $Id: lstate.h,v 2.44 2009/06/01 19:09:26 roberto Exp roberto $
+** $Id: lstate.h,v 2.45 2009/06/18 18:59:18 roberto Exp roberto $
** Global State
** See Copyright Notice in lua.h
*/
@@ -163,7 +163,6 @@ struct lua_State {
StkId top; /* first free slot in the stack */
global_State *l_G;
CallInfo *ci; /* call info for current function */
- int nci; /* number of total CallInfo structures linked */
const Instruction *oldpc; /* last pc traced */
StkId stack_last; /* last free slot in the stack */
StkId stack; /* stack base */
diff --git a/ltests.c b/ltests.c
@@ -1,5 +1,5 @@
/*
-** $Id: ltests.c,v 2.65 2009/06/15 19:51:31 roberto Exp roberto $
+** $Id: ltests.c,v 2.66 2009/06/17 17:53:14 roberto Exp roberto $
** Internal Module for Debugging of the Lua Implementation
** See Copyright Notice in lua.h
*/
@@ -570,7 +570,6 @@ static int stacklevel (lua_State *L) {
unsigned long a = 0;
lua_pushinteger(L, (L->top - L->stack));
lua_pushinteger(L, (L->stack_last - L->stack));
- lua_pushinteger(L, L->nci);
lua_pushinteger(L, (unsigned long)&a);
return 5;
}
diff --git a/lua.h b/lua.h
@@ -1,5 +1,5 @@
/*
-** $Id: lua.h,v 1.239 2009/06/17 17:49:44 roberto Exp roberto $
+** $Id: lua.h,v 1.240 2009/06/18 18:59:18 roberto Exp roberto $
** Lua - An Extensible Extension Language
** Lua.org, PUC-Rio, Brazil (http://www.lua.org)
** See Copyright Notice at the end of this file
@@ -33,7 +33,7 @@
/*
** pseudo-indices
*/
-#define LUA_REGISTRYINDEX (-(LUAI_MCS_AUX) - 1)
+#define LUA_REGISTRYINDEX LUAI_FIRSTPSEUDOIDX
#define LUA_ENVIRONINDEX (LUA_REGISTRYINDEX - 1)
#define LUA_GLOBALSINDEX (LUA_ENVIRONINDEX - 1)
#define lua_upvalueindex(i) (LUA_GLOBALSINDEX-(i))
diff --git a/luaconf.h b/luaconf.h
@@ -1,5 +1,5 @@
/*
-** $Id: luaconf.h,v 1.105 2009/06/18 18:19:36 roberto Exp roberto $
+** $Id: luaconf.h,v 1.106 2009/07/01 16:16:40 roberto Exp roberto $
** Configuration file for Lua
** See Copyright Notice in lua.h
*/
@@ -417,31 +417,19 @@
/*
-@@ LUAI_MAXCALLS limits the number of nested calls.
-** CHANGE it if you need really deep recursive calls. This limit is
-** arbitrary; its only purpose is to stop infinite recursion before
-** exhausting memory.
-*/
-#define LUAI_MAXCALLS 20000
-
-
-/*
-@@ LUAI_MAXCSTACK limits the number of Lua stack slots that a C function
-@* can use.
+@@ LUAI_MAXSTACK limits the size of the Lua stack.
** CHANGE it if you need a different limit. This limit is arbitrary;
-** its only purpose is to stop C functions to consume unlimited stack
-** space.
+** its only purpose is to stop Lua to consume unlimited stack
+** space (and to reserve some numbers for pseudo-indices).
*/
-/* life is simpler if stack size fits in an int (16 is an estimate
- for the size of a Lua value) */
-#if SHRT_MAX < (INT_MAX / 16)
-#define LUAI_MCS_AUX SHRT_MAX
+#if LUAI_BITSINT >= 32
+#define LUAI_MAXSTACK 1000000
#else
-#define LUAI_MCS_AUX (INT_MAX / 16)
+#define LUAI_MAXSTACK 15000
#endif
-/* reserve some space for pseudo-indices */
-#define LUAI_MAXCSTACK (LUAI_MCS_AUX - 1000)
+/* reserve some space for error handling */
+#define LUAI_FIRSTPSEUDOIDX (-LUAI_MAXSTACK - 1000)
