On Tue, Sep 18, 2012 at 1:21 PM, Zdenek Styblik
<zdenek.styb...@gmail.com> wrote:
> On Mon, Sep 17, 2012 at 3:46 PM, <dick.detwei...@emerson.com> wrote:
>>
>> Hello all,
>>
>> I lead a group that uses ipmitool in server control software we write and
>> maintain. We have uncovered a curious issue with ipmitool's 'sel set time'
>> and 'exec' commands. This is using ipmitool version 1.8.10. I have looked
>> through the change logs for 1.8.11 and 12 and not seen this problem
>> addressed.
>>
>> If we issue 'sel set time' from the command line, and then put the exact
>> same command into a file and use exec to execute it, we get an hour's
>> difference in the commands. Here is a screen shot:
>>
>> Is this a known issue?
>>
>> Thanks,
>> Dick
>>
>
> Hello Dick,
>
> to tell you whether it is known issue or not; it is hard when people
> refuse to use SF.net bug tracker. I don't remember seeing this one in
> there, so I'd say it is not a known issue.
>
> Anyway, here is what I got and what I got to:
>
> ~~~ debug output
> [root@host ~]# /tmp/package-ipmitool/usr/local/bin/ipmitool sel time
> set "09/14/2012 18:30:00"
> TM before mktime()
> hour: 18
> min: 30
> isdst: 3
> tz1: 'GMT'
> tz2: 'GMT'
> ---
> TM after mktime()
> hour: 18
> min: 30
> isdst: 1
> tz1: 'CET'
> tz2: 'CEST'
> ---
> Leaving time alone.
>
> Delta is '2'
>
> 09/14/2012 18:30:00
> [root@host ~]# /tmp/package-ipmitool/usr/local/bin/ipmitool exec time
> TM before mktime()
> hour: 18
> min: 30
> isdst: 0
> tz1: 'GMT'
> tz2: 'GMT'
> ---
> TM after mktime()
> hour: 19
> min: 30
> isdst: 1
> tz1: 'CET'
> tz2: 'CEST'
> ---
> Leaving time alone.
>
> Delta is '2'
>
> 09/14/2012 19:30:00
> ~~~ debug output
>
> The reason, as you can see, is tm.tm_isdst being set to random value.
> And once it is set to value 0, other time it is set to > 0. Setting
> tm.tm_isdst to (-1) prior calling mktime() gives, at least,
> deterministic behaviour.
>
> From mktime() man page:
> ``The value specified in the tm_isdst field informs mktime() whether
> or not daylight saving time (DST) is in effect for the time supplied
> in the tm structure: a positive value means DST is in effect;
> zero means that DST is not in effect; and a negative value means that
> mktime() should (use timezone information and system databases to)
> attempt to determine whether DST is in effect at the specified time.''
>
Ok, "should" is not "always" as written below. I'm wondering whether
it means it is not going to work (reliably) for some platforms(meaning
OS).
> In other words and short, the following change will force mktime() to
> *always* check whether DST is in use or not instead of using random
> value. One way or another, use of random value set in/to tm.tm_isdst
> should be eliminated!
>
> ~~~ snip lib/ipmi_sel.c
> if (strptime(time_string, time_format, &tm) == 0) {
> lprintf(LOG_ERR, "Specified time could not be
> parsed");
> return -1;
> }
> tm.tm_isdst = (-1);
> t = mktime(&tm);
> if (t < 0) {
> lprintf(LOG_ERR, "Specified time could not be
> parsed");
> return -1;
> }
> ~~~ snip lib/ipmi_sel.c
>
> I can't put more time into this right now, but debug above should give
> enough clues what's wrong. And actually, patch/fix seems to be solid
> to me. Please note, however, that Host's timezone is used and that
> might not be what you intended. In such case another parameter that
> specifies timezone should be added.
>
> Please fill SF.net ticket(or tickets, because these are two separate
> things!) for this. If you don't have SF.net account/access, please,
> say so.
>
> Thanks and regards,
> Z.
>
>>
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