Fix duplocale (libc/locale/duplocale.c) which fails to properly call __loadlocale
Problem:
After passing locales created by 'duplocale' to 'uselocale',
referencing 'MB_CUR_MAX', which is actually expanded to
'__locale_mb_cur_max()' by preprocessors, causes segmentation faults.
Direct use of locales from 'newlocale' does not cause the problem.
This is the problem of 'duplocale'.
int main(void) {
locale_t const loc = newlocale(LC_ALL_MASK, "", NULL);
locale_t const dup = duplocale(loc);
locale_t const old = uselocale(dup);
var = MB_CUR_MAX; /* <-- crashes here */
uselocale(old);
freelocale(dup);
freelocale(loc);
return 0;
}
$ gcc test.c
$ ./a
Segmentation fault (core dumped)
# Note: "core dumped" in the above message was actually written in
# Japanese, but I translated the part to post a mail in English.
Bug:
In the beginning of '__loadlocale' (newlib/libc/locale/locale.c:501),
there is a code which checks if the operations can be skipped:
> /* Avoid doing everything twice if nothing has changed. */
> if (!strcmp (new_locale, loc->categories[category]))
> return loc->categories[category];
While, in the function '_duplocale_r' (newlib/libc/locale/
duplocale.c), '__loadlocale' is called as in the quoted codes:
> /* If the object is not a "C" locale category, copy it. Just call
> __loadlocale. It knows what to do to replicate the category. */
> tmp_locale.lc_cat[i].ptr = NULL;
> tmp_locale.lc_cat[i].buf = NULL;
> if (!__loadlocale (&tmp_locale, i, tmp_locale.categories[i]))
> goto error;
This call of '__loadlocale' results in the skip check being