Re: mismatch of type of ut_tv.tv_sec between glibc-2.41 and utmp(5)

[Florian Weimer <fw@deneb.enyo.de>]

* Thomas Orgis:

> I don't know the history … did it use to be a signed integer and
> someone decided to buy some time by making it unsigned?

Yes, this changed in glibc 2.40.  Some distributions may have
backported it.

commit 5361ad3910c257bc327567be76fde532ed238e42
Author: Florian Weimer <fweimer@redhat.com>
Date:   Fri Apr 19 14:38:17 2024 +0200

    login: Use unsigned 32-bit types for seconds-since-epoch
    
    These fields store timestamps when the system was running.  No Linux
    systems existed before 1970, so these values are unused.  Switching
    to unsigned types allows continued use of the existing struct layouts
    beyond the year 2038.
    
    The intent is to give distributions more time to switch to improved
    interfaces that also avoid locking/data corruption issues.
    
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> Now I have to think how elaborately I want to handle possible overflow
> from time_t assigning to uint32_t with the recommended way of using
> gettimeofday() for utmp …

On the other hand, utmp is pretty much obsolete because the design
assumes a fixed number of terminal lines.