Avoid calling 'fprintf' with NULL

Avoid undefined behavior in calls like «fprintf("%s", NULL)».
('lua_writestringerror' is implemented as 'fprintf', and 'lua_tostring'
can return NULL if object is not a string.)
This commit is contained in:
Roberto Ierusalimschy 2020-06-09 16:12:01 -03:00
parent 63295f1f7f
commit 364e569945
3 changed files with 7 additions and 3 deletions

View File

@ -995,8 +995,10 @@ static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
static int panic (lua_State *L) {
const char *msg = lua_tostring(L, -1);
if (msg == NULL) msg = "error object is not a string";
lua_writestringerror("PANIC: unprotected error in call to Lua API (%s)\n",
lua_tostring(L, -1));
msg);
return 0; /* return to Lua to abort */
}

View File

@ -417,7 +417,7 @@ static int db_debug (lua_State *L) {
return 0;
if (luaL_loadbuffer(L, buffer, strlen(buffer), "=(debug command)") ||
lua_pcall(L, 0, 0, 0))
lua_writestringerror("%s\n", lua_tostring(L, -1));
lua_writestringerror("%s\n", luaL_tolstring(L, -1, NULL));
lua_settop(L, 0); /* remove eventual returns */
}
}

View File

@ -73,8 +73,10 @@ static void badexit (const char *fmt, const char *s1, const char *s2) {
static int tpanic (lua_State *L) {
const char *msg = lua_tostring(L, -1);
if (msg == NULL) msg = "error object is not a string";
return (badexit("PANIC: unprotected error in call to Lua API (%s)\n",
lua_tostring(L, -1), NULL),
msg, NULL),
0); /* do not return to Lua */
}