package/lua: implement memory limits, scripts can use get_memory_limit() and set_memory_limit() to cap the maximum ram usage

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@16753 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 277 insertions, 0 deletions

diff --git a/package/lua/patches/040-memory-limits.patch b/package/lua/patches/040-memory-limits.patch
new file mode 100644
index 0000000000..52bae6ae85
--- /dev/null
+++ b/package/lua/patches/040-memory-limits.patch
@@ -0,0 +1,277 @@
+--- a/src/lapi.c
++++ b/src/lapi.c
+@@ -716,14 +716,14 @@
+ 
+ LUA_API void lua_setfield (lua_State *L, int idx, const char *k) {
+   StkId t;
+-  TValue key;
+   lua_lock(L);
+   api_checknelems(L, 1);
+   t = index2adr(L, idx);
+   api_checkvalidindex(L, t);
+-  setsvalue(L, &key, luaS_new(L, k));
+-  luaV_settable(L, t, &key, L->top - 1);
+-  L->top--;  /* pop value */
++  setsvalue2s(L, L->top, luaS_new(L, k));
++  api_incr_top(L);
++  luaV_settable(L, t, L->top - 1, L->top - 2);
++  L->top -= 2;  /* pop key and value */
+   lua_unlock(L);
+ }
+ 
+@@ -971,7 +971,12 @@
+       break;
+     }
+     case LUA_GCCOLLECT: {
+-      luaC_fullgc(L);
++      lu_mem old_thres = g->GCthreshold;
++      if(g->GCthreshold != MAX_LUMEM) {
++        g->GCthreshold = MAX_LUMEM;
++        luaC_fullgc(L);
++        g->GCthreshold = old_thres;
++      }
+       break;
+     }
+     case LUA_GCCOUNT: {
+--- a/src/ldo.c
++++ b/src/ldo.c
+@@ -494,6 +494,7 @@
+   struct SParser *p = cast(struct SParser *, ud);
+   int c = luaZ_lookahead(p->z);
+   luaC_checkGC(L);
++	lua_gc(L, LUA_GCSTOP, 0);  /* stop collector during parsing */
+   tf = ((c == LUA_SIGNATURE[0]) ? luaU_undump : luaY_parser)(L, p->z,
+                                                              &p->buff, p->name);
+   cl = luaF_newLclosure(L, tf->nups, hvalue(gt(L)));
+@@ -502,6 +503,7 @@
+     cl->l.upvals[i] = luaF_newupval(L);
+   setclvalue(L, L->top, cl);
+   incr_top(L);
++	lua_gc(L, LUA_GCRESTART, 0);
+ }
+ 
+ 
+--- a/src/lgc.c
++++ b/src/lgc.c
+@@ -437,7 +437,10 @@
+   /* check size of buffer */
+   if (luaZ_sizebuffer(&g->buff) > LUA_MINBUFFER*2) {  /* buffer too big? */
+     size_t newsize = luaZ_sizebuffer(&g->buff) / 2;
+-    luaZ_resizebuffer(L, &g->buff, newsize);
++    /* make sure newsize is larger then the buffer's in use size. */
++    newsize = (luaZ_bufflen(&g->buff) > newsize) ? luaZ_bufflen(&g->buff) : newsize;
++    if(newsize < luaZ_sizebuffer(&g->buff))
++      luaZ_resizebuffer(L, &g->buff, newsize);
+   }
+ }
+ 
+--- a/src/lstate.c
++++ b/src/lstate.c
+@@ -118,7 +118,6 @@
+ 
+ lua_State *luaE_newthread (lua_State *L) {
+   lua_State *L1 = tostate(luaM_malloc(L, state_size(lua_State)));
+-  luaC_link(L, obj2gco(L1), LUA_TTHREAD);
+   preinit_state(L1, G(L));
+   stack_init(L1, L);  /* init stack */
+   setobj2n(L, gt(L1), gt(L));  /* share table of globals */
+@@ -126,6 +125,7 @@
+   L1->basehookcount = L->basehookcount;
+   L1->hook = L->hook;
+   resethookcount(L1);
++  luaC_link(L, obj2gco(L1), LUA_TTHREAD);
+   lua_assert(iswhite(obj2gco(L1)));
+   return L1;
+ }
+--- a/src/lstring.c
++++ b/src/lstring.c
+@@ -53,6 +53,9 @@
+   stringtable *tb;
+   if (l+1 > (MAX_SIZET - sizeof(TString))/sizeof(char))
+     luaM_toobig(L);
++  tb = &G(L)->strt;
++  if ((tb->nuse + 1) > cast(lu_int32, tb->size) && tb->size <= MAX_INT/2)
++    luaS_resize(L, tb->size*2);  /* too crowded */
+   ts = cast(TString *, luaM_malloc(L, (l+1)*sizeof(char)+sizeof(TString)));
+   ts->tsv.len = l;
+   ts->tsv.hash = h;
+@@ -61,13 +64,10 @@
+   ts->tsv.reserved = 0;
+   memcpy(ts+1, str, l*sizeof(char));
+   ((char *)(ts+1))[l] = '\0';  /* ending 0 */
+-  tb = &G(L)->strt;
+   h = lmod(h, tb->size);
+   ts->tsv.next = tb->hash[h];  /* chain new entry */
+   tb->hash[h] = obj2gco(ts);
+   tb->nuse++;
+-  if (tb->nuse > cast(lu_int32, tb->size) && tb->size <= MAX_INT/2)
+-    luaS_resize(L, tb->size*2);  /* too crowded */
+   return ts;
+ }
+ 
+--- a/src/ltable.c
++++ b/src/ltable.c
+@@ -371,7 +371,6 @@
+ 
+ Table *luaH_new (lua_State *L, int narray, int nhash) {
+   Table *t = luaM_new(L, Table);
+-  luaC_link(L, obj2gco(t), LUA_TTABLE);
+   t->metatable = NULL;
+   t->flags = cast_byte(~0);
+   /* temporary values (kept only if some malloc fails) */
+@@ -381,6 +380,7 @@
+   t->node = cast(Node *, dummynode);
+   setarrayvector(L, t, narray);
+   setnodevector(L, t, nhash);
++  luaC_link(L, obj2gco(t), LUA_TTABLE);
+   return t;
+ }
+ 
+--- a/src/lvm.c
++++ b/src/lvm.c
+@@ -375,6 +375,7 @@
+         if (l >= MAX_SIZET - tl) luaG_runerror(L, "string length overflow");
+         tl += l;
+       }
++      G(L)->buff.n = tl;
+       buffer = luaZ_openspace(L, &G(L)->buff, tl);
+       tl = 0;
+       for (i=n; i>0; i--) {  /* concat all strings */
+@@ -383,6 +384,7 @@
+         tl += l;
+       }
+       setsvalue2s(L, top-n, luaS_newlstr(L, buffer, tl));
++      luaZ_resetbuffer(&G(L)->buff);
+     }
+     total -= n-1;  /* got `n' strings to create 1 new */
+     last -= n-1;
+--- a/src/lua.c
++++ b/src/lua.c
+@@ -19,6 +19,82 @@
+ #include "llimits.h"
+ 
+ 
++typedef struct {
++	char		*name;
++	lua_State	*L;
++	size_t		memused;
++	size_t		peak_memused;
++	size_t		max_memused;
++	int		collecting;
++} script_info_t;
++
++
++static void *script_alloc(void *ud, void *ptr, size_t osize, size_t nsize)
++{
++	script_info_t *info=(script_info_t *)ud;
++	size_t old_size = info->memused;
++
++	info->memused -= osize;
++	if (nsize == 0) {
++		free(ptr);
++		return NULL;
++	}
++	info->memused += nsize;
++	if(info->max_memused > 0 && nsize > osize && info->memused >= info->max_memused) {
++#ifdef LOW_MEM_DEBUG
++		printf("LOW MEM: 1 osize=%zd, nsize=%zd, used=%zu, peak=%zu, need=%zd\n", osize, nsize,
++			info->memused, info->peak_memused, (info->memused - info->max_memused));
++#endif
++		info->memused = old_size;
++		/* don't allow a recursive garbage collection call. */
++		if(info->collecting != 0) {
++			return NULL;
++		}
++		info->collecting = 1;
++		/* try to free memory by collecting garbage. */
++		lua_gc(info->L, LUA_GCCOLLECT, 0);
++		info->collecting = 0;
++#ifdef LOW_MEM_DEBUG
++		printf("LOW MEM: 2 used=%zu, peak=%zu\n", info->memused, info->peak_memused);
++#endif
++		/* check memory usage again. */
++		old_size = info->memused;
++		info->memused -= osize;
++		info->memused += nsize;
++		if(info->memused >= info->max_memused) {
++			info->memused = old_size;
++#ifdef LOW_MEM_DEBUG
++			printf("OUT OF MEMORY: memused=%zd, osize=%zd, nsize=%zd\n", info->memused, osize, nsize);
++#endif
++			return NULL;
++		}
++	}
++	if(info->memused > info->peak_memused) info->peak_memused = info->memused;
++	return realloc(ptr, nsize);
++}
++
++static int set_memory_limit(lua_State *L)
++{
++	int limit = luaL_checknumber(L, 1);
++	script_info_t *info;
++	lua_getallocf(L, (void *)(&info));
++
++	if( limit >= 0 )
++		info->max_memused = limit;
++
++	lua_pushnumber(L, limit);
++	return 1;
++}
++
++static int get_memory_limit(lua_State *L)
++{
++	script_info_t *info;
++	lua_getallocf(L, (void *)(&info));
++	lua_pushnumber(L, info->max_memused);
++	return 1;
++}
++
++
+ static lua_State *globalL = NULL;
+ 
+ static const char *progname = LUA_PROGNAME;
+@@ -377,11 +453,28 @@
+ int main (int argc, char **argv) {
+   int status;
+   struct Smain s;
+-  lua_State *L = lua_open();  /* create state */
++  script_info_t *info;
++
++  info = (script_info_t *)calloc(1, sizeof(script_info_t));
++  info->max_memused = 0;
++  info->collecting = 0;
++  info->name = argv[0];
++  info->memused = 0;
++  info->peak_memused = 0;
++
++  lua_State *L = lua_newstate(script_alloc, info);
++
+   if (L == NULL) {
+     l_message(argv[0], "cannot create state: not enough memory");
+     return EXIT_FAILURE;
+   }
++
++  info->L = L;
++
++  luaL_openlibs(L);
++  lua_register(L, "set_memory_limit", set_memory_limit);
++  lua_register(L, "get_memory_limit", get_memory_limit);
++
+   /* Checking 'sizeof(lua_Integer)' cannot be made in preprocessor on all compilers.
+   */
+ #ifdef LNUM_INT16
+@@ -396,6 +489,14 @@
+   status = lua_cpcall(L, &pmain, &s);
+   report(L, status);
+   lua_close(L);
++
++#ifdef LOW_MEM_DEBUG
++  printf("%s: memused=%zd, peak_memused=%zd\n", info->name,
++	info->memused, info->peak_memused);
++#endif
++
++  free(info);
++
+   return (status || s.status) ? EXIT_FAILURE : EXIT_SUCCESS;
+ }
+