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Finalizers may call functions from a dynamic library after

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the library has been unloaded
This commit is contained in:
Roberto Ierusalimschy 2012-04-12 13:25:25 -03:00
parent b10dbe5c72
commit 1485ea2ee7
1 changed files with 102 additions and 2 deletions
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104
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@ -1880,8 +1880,8 @@ patch = [[
+++ lundump.c 2008/04/04 19:51:41 2.7.1.4
@@ -1,5 +1,5 @@
/*
-** $Id: bugs,v 1.111 2011/10/21 19:34:23 roberto Exp roberto $
+** $Id: bugs,v 1.111 2011/10/21 19:34:23 roberto Exp roberto $
-** $Id: bugs,v 1.112 2012/01/20 18:32:13 roberto Exp roberto $
+** $Id: bugs,v 1.112 2012/01/20 18:32:13 roberto Exp roberto $
** load precompiled Lua chunks
** See Copyright Notice in lua.h
*/
@ -2520,6 +2520,106 @@ patch = [[
]]
}
Bug{
what = [[Finalizers may call functions from a dynamic library after
the library has been unloaded]],
report = [[Josh Haberman, 2012/04/08]],
since = [[5.1]],
example = [[
local u = setmetatable({}, {__gc = function () foo() end})
local m = require 'mod' -- 'mod' may be any dynamic library written in C
foo = m.foo -- 'foo' may be any function from 'mod'
-- end program; it crashes
]],
patch = [[
===================================================================
RCS file: RCS/loadlib.c,v
retrieving revision 1.108
diff -r1.108 loadlib.c
95c95
< #define LIBPREFIX "LOADLIB: "
---
> #define CLIBS "_CLIBS"
251,266c251,256
<
< static void **ll_register (lua_State *L, const char *path) {
< void **plib;
< lua_pushfstring(L, "%s%s", LIBPREFIX, path);
< lua_gettable(L, LUA_REGISTRYINDEX); /* check library in registry? */
< if (!lua_isnil(L, -1)) /* is there an entry? */
< plib = (void **)lua_touserdata(L, -1);
< else { /* no entry yet; create one */
< lua_pop(L, 1); /* remove result from gettable */
< plib = (void **)lua_newuserdata(L, sizeof(const void *));
< *plib = NULL;
< luaL_setmetatable(L, "_LOADLIB");
< lua_pushfstring(L, "%s%s", LIBPREFIX, path);
< lua_pushvalue(L, -2);
< lua_settable(L, LUA_REGISTRYINDEX);
< }
---
> static void *ll_checkclib (lua_State *L, const char *path) {
> void *plib;
> lua_getfield(L, LUA_REGISTRYINDEX, CLIBS);
> lua_getfield(L, -1, path);
> plib = lua_touserdata(L, -1); /* plib = CLIBS[path] */
> lua_pop(L, 2); /* pop CLIBS table and 'plib' */
270a261,270
> static void ll_addtoclib (lua_State *L, const char *path, void *plib) {
> lua_getfield(L, LUA_REGISTRYINDEX, CLIBS);
> lua_pushlightuserdata(L, plib);
> lua_pushvalue(L, -1);
> lua_setfield(L, -3, path); /* CLIBS[path] = plib */
> lua_rawseti(L, -2, luaL_len(L, -2) + 1); /* CLIBS[#CLIBS + 1] = plib */
> lua_pop(L, 1); /* pop CLIBS table */
> }
>
>
272,273c272,273
< ** __gc tag method: calls library's `ll_unloadlib' function with the lib
< ** handle
---
> ** __gc tag method for CLIBS table: calls 'll_unloadlib' for all lib
> ** handles in list CLIBS
276,278c276,281
< void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");
< if (*lib) ll_unloadlib(*lib);
< *lib = NULL; /* mark library as closed */
---
> int n = luaL_len(L, 1);
> for (; n >= 1; n--) { /* for each handle, in reverse order */
> lua_rawgeti(L, 1, n); /* get handle CLIBS[n] */
> ll_unloadlib(lua_touserdata(L, -1));
> lua_pop(L, 1); /* pop handle */
> }
284,286c287,292
< void **reg = ll_register(L, path);
< if (*reg == NULL) *reg = ll_load(L, path, *sym == '*');
< if (*reg == NULL) return ERRLIB; /* unable to load library */
---
> void *reg = ll_checkclib(L, path); /* check loaded C libraries */
> if (reg == NULL) { /* must load library? */
> reg = ll_load(L, path, *sym == '*');
> if (reg == NULL) return ERRLIB; /* unable to load library */
> ll_addtoclib(L, path, reg);
> }
292c298
< lua_CFunction f = ll_sym(L, *reg, sym);
---
> lua_CFunction f = ll_sym(L, reg, sym);
675,676c681,683
< /* create new type _LOADLIB */
< luaL_newmetatable(L, "_LOADLIB");
---
> /* create table CLIBS to keep track of loaded C libraries */
> luaL_getsubtable(L, LUA_REGISTRYINDEX, CLIBS);
> lua_createtable(L, 0, 1); /* metatable for CLIBS */
678a686
> lua_setmetatable(L, -2);
]]
}
--[=[
Bug{
what = [[ ]],