On Tue, May 26, 2020 at 12:13:02AM +0200, Ingo Schwarze wrote: > Hi, > > my impression is there are two totally independent topics in this > thread. > > 1. Whether and how to make things safer, ideally terminating the > program in a controlled manner, if it uses functions that are > not thread-safe in an invalid manner. I'm not addressing that > topic in this mail. > > 2. Whether we want additional non-standard xlocale.h functions > in our libc. > > Regarding topic 2, let me say up front that i do not feel strongly > either way. It seems to me this is mostly a question for porters. > If some functions are widely used - even if non-standard - and help > avoid porting hassle, then sure, let's have them unless they cause > excessive fuss. But the latter does not seem likely here. > > There are a number of functions that seem likely useful to me off > the top of my head, for example: querylocale, nl_langinfo_l, > MB_CUR_MAX_L, wcwidth_l > > In general, i must say i like the whole xlocale.h business not all > that much: in a nutshell, it is doubling the number of half the > functions under the sun, which usually indicates poor design in the > first place, and then the vast majority of these additional functions > are almost useless on any operating system and totally useless on > OpenBSD. Like, i mean, btowc_l(3)? Or even the isdigit_l(3) which > we already have? You must be choking, Mr. Chisnall! I don't think > stuff should be added because it is out there, but only if there is > at least some porting benefit. > > Regarding the FreeBSD headers, i like them even less. There are both > terrible design choices and terrible implementation choices. Regarding > design, it appears that you *must* #include <xlocale.h> after other > headers - if you include it before, it won't work. Regarding > implementation, there is quite repulsive macro abuse in xlocale/_ctype.h; > but probably that can be unrolled in LibreSSL style. Either way, none > of that hinders providing them if doing so yields benefit. > > See below for a list of functions that i drafted extremely quickly, > so beware of errors and omissions. The point isn't to present a > definite plan. The point is merely to demonstrate the sheer fatness > of the animal and to give a first impression of the degree to which > it stinks and grunts from most of its ends. > > If any of this is needed, do porters already know which functions > are in particularly high demand? Do you have any idea how to find > out which ones are actually useful for porting purposes?
Serendipity Today, I looked at an older library for audit purposes. Library is called udns. If you look at the code, there's a lot of apparently useless reinvention, like the code explicitly checks for digits using c >= '0' && c <= '9' patterns (or isprint for that matter). Thinking some more, I realized why: this is library code, so it can't assume it's running under any kind of sensible locale unless it has asserted it itself. In that specific context, isdigit_l and friends make a lot of sense. Either that, or systematic uselocale wrappers for any function that can be called from outside. (yes, I now that isdigit/isspace are not a problem on OpenBSD, but they can be elsewhere!)
