BUG/MINOR: lua: use strlcpy2() not strncpy() to copy sample keywords

The lua initialization code which creates the Lua mapping of all converters
and sample fetch keywords makes use of strncpy(), and as such can take ages
to start with large values of tune.bufsize because it spends its time zeroing
gigabytes of memory for nothing. A test performed with an extreme value of
16 MB takes roughly 4 seconds, so it's possible that some users with huge
1 MB buffers (e.g. for payload analysis) notice a small startup latency.
However this does not affect config checks since the Lua stack is not yet
started. Let's replace this with strlcpy2().

This should be backported to all supported versions.

diff --git a/src/hlua.c b/src/hlua.c
index ea9d31cdbd2c2ab6cc9a7b73c34f3b30877b185c..7b280884db9d5f5d902e43a70dcff0e57481379d 100644 (file)
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -11372,8 +11372,7 @@ lua_State *hlua_init_state(int thread_num)
                /* gL.Tua doesn't support '.' and '-' in the function names, replace it
                 * by an underscore.
                 */
-               strncpy(trash.area, sf->kw, trash.size);
-               trash.area[trash.size - 1] = '\0';
+               strlcpy2(trash.area, sf->kw, trash.size);
                for (p = trash.area; *p; p++)
                        if (*p == '.' || *p == '-' || *p == '+')
                                *p = '_';
@@ -11411,8 +11410,7 @@ lua_State *hlua_init_state(int thread_num)
                /* gL.Tua doesn't support '.' and '-' in the function names, replace it
                 * by an underscore.
                 */
-               strncpy(trash.area, sc->kw, trash.size);
-               trash.area[trash.size - 1] = '\0';
+               strlcpy2(trash.area, sc->kw, trash.size);
                for (p = trash.area; *p; p++)
                        if (*p == '.' || *p == '-' || *p == '+')
                                *p = '_';