Re: [PATCH] time: strftime_l: Use malloc rather than an unbounded alloca.

[Paul Eggert]

On 2023-05-17 04:04, Adhemerval Zanella Netto wrote:
> do you think it would be feasible to assume
> _POSIX_TZNAME_MAX or 48 (for Factory zone) to avoid the malloc call on
> strftime_l?

ALthough it's technically feasible, it'd be some work. Among other 
things, whatever limit we chose would have to become visible via 
<limits.h> and sysconf and etc., and we'd need to document that there is 
now a limit. Better, I think, would be to continue to follow the GNU 
coding standards and not impose an arbitrary limit on time zone 
abbreviation length, even for the highly unusual case where code is 
calling wcsftime or wcsftime_l.

How about avoiding the malloc in the following way? I installed the 
attached patch into Gnulib lib/nstrftime.c, which has forked from glibc 
but with some work could be merged back in, and this should also fix the 
glibc bugs with buffer sizes exceeding INT_MAX.

If you don't want all the hassle of merging, you can cherry-pick this 
patch. I haven't tested the patch, though, as Gnulib does not use this code.

0001-nstrftime-suggest-to-glibc-how-to-avoid-alloca.patch
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