Are ut_user and ut_host in struct utmp NUL-terminated?

[Michael Kerrisk (man-pages)]

On 08/13/2018 02:10 PM, Florian Weimer wrote:
> Can ut_user be exactly UT_NAMESIZE bytes long?  Or is it necessary to 
> set aside a byte with the NUL terminator?
> 
> I'm not sure what POSIX says about struct utmpx.  It never says “string” 
> in the context of ut_user, so I don't think it clarifies this matter.

Each of the char fields in utmp/utmpx can be completely filled with
characters. (I.e., there may not be a terminating null byte.)
As you note, POSIX does not say much here, but perhaps the fact that
the term "string" is not mentioned is a clue.

Thanks,

Michael


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
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