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`__tostring' for files + small bug (could do invalid read inside

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a userdata when it was not a file)
This commit is contained in:
Roberto Ierusalimschy 2002-11-25 13:05:39 -02:00
parent e47baca75a
commit d9340154ac
1 changed files with 35 additions and 20 deletions
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55
liolib.c
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@ -1,5 +1,5 @@
/*
** $Id: liolib.c,v 2.23 2002/11/14 15:41:38 roberto Exp roberto $
** $Id: liolib.c,v 2.24 2002/11/18 16:53:19 roberto Exp roberto $
** Standard I/O (and system) library
** See Copyright Notice in lua.h
*/
@ -54,23 +54,26 @@ static int pushresult (lua_State *L, int i, const char *filename) {
}
static FILE *tofile (lua_State *L, int findex) {
static FILE **topfile (lua_State *L, int findex) {
FILE **f = (FILE **)lua_touserdata(L, findex);
if (f && *f && lua_getmetatable(L, findex) &&
lua_rawequal(L, -1, lua_upvalueindex(1))) {
lua_pop(L, 1);
return *f;
if (f == NULL || !lua_getmetatable(L, findex) ||
!lua_rawequal(L, -1, lua_upvalueindex(1))) {
luaL_argerror(L, findex, "bad file");
}
if (findex > 0) {
if (f && *f == NULL)
luaL_error(L, "attempt to use a closed file");
else
luaL_argerror(L, findex, "bad file");
}
return NULL;
lua_pop(L, 1);
return f;
}
static FILE *tofile (lua_State *L, int findex) {
FILE **f = topfile(L, findex);
if (*f == NULL)
luaL_error(L, "attempt to use a closed file");
return *f;
}
/*
** When creating file handles, always creates a `closed' file handle
** before opening the actual file; so, if there is a memory error, the
@ -126,13 +129,25 @@ static int io_close (lua_State *L) {
static int io_gc (lua_State *L) {
FILE **f = (FILE **)lua_touserdata(L, 1);
if (!(f && *f == NULL)) /* ignore closed files */
FILE **f = topfile(L, 1);
if (*f != NULL) /* ignore closed files */
aux_close(L);
return 0;
}
static int io_tostring (lua_State *L) {
char buff[32];
FILE **f = topfile(L, 1);
if (*f == NULL)
strcpy(buff, "closed");
else
sprintf(buff, "%p", lua_touserdata(L, 1));
lua_pushfstring(L, "file (%s)", buff);
return 1;
}
static int io_open (lua_State *L) {
const char *filename = luaL_checkstring(L, 1);
const char *mode = luaL_optstring(L, 2, "r");
@ -164,13 +179,9 @@ static int io_tmpfile (lua_State *L) {
static FILE *getiofile (lua_State *L, const char *name) {
FILE *f;
lua_pushstring(L, name);
lua_rawget(L, lua_upvalueindex(1));
f = tofile(L, -1);
if (f == NULL)
luaL_error(L, "%s is closed", name);
return f;
return tofile(L, -1);
}
@ -478,6 +489,10 @@ static void createmeta (lua_State *L) {
lua_pushvalue(L, -2); /* push metatable (will be upvalue for `gc' method) */
lua_pushcclosure(L, io_gc, 1);
lua_rawset(L, -3); /* metatable.__gc = io_gc */
lua_pushliteral(L, "__tostring");
lua_pushvalue(L, -2); /* push metatable */
lua_pushcclosure(L, io_tostring, 1);
lua_rawset(L, -3);
/* file methods */
lua_pushliteral(L, "__index");
lua_pushvalue(L, -2); /* push metatable */