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From: Marcel Holtmann <>
To: Arnd Bergmann <>
Cc: Bluez mailing list <>,
	y2038 Mailman List <>,
	Johan Hedberg <>,
	Linux Kernel Mailing List <>,
	Deepa Dinamani <>,
	Rich Felker <>, Guy Harris <>
Subject: Re: [RFC] y2038: HCI_TIME_STAMP with time64
Date: Fri, 10 Jan 2020 18:52:41 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Hi Arnd,

>>> I noticed earlier this week that the HCI_CMSG_TSTAMP/HCI_TIME_STAMP
>>> interface has no time64 equivalent, as we apparently missed that when
>>> converting the normal socket timestamps to support both time32 and time64
>>> variants of the sockopt and cmsg data.
> ...
>>> When using HCI_TIME_STAMP on a 32-bit system with a time64
>>> libc, users will interpret the { s32 tv_sec; s32 tv_usec } layout of
>>> the kernel as { s64 tv_sec; ... }, which puts complete garbage
>>> into the timestamp regardless of whether this code runs before or
>>> after y2038. From looking at, I found two
>>> users of this: libpcap and hcidump. There are probably others that
>>> are not part of Debian.
> ...
>>> 3. Add support for the normal SO_TIMESTAMPNS_NEW sockopt in
>>>  HCI, providing timestamps in the unambiguous { long long tv_sec;
>>>  long long tv_nsec; } format to user space, and change applications
>>>  to use that if supported by the kernel.
>> I have added SO_TIMESTAMP* to every Bluetooth socket a while back. And that should be used by the majority of the tools. One exception might by hcidump which has been replaced by btmon already anyway.
>> So I would not bother with HCI_TIME_STAMP fixing. We can do 2) if someone really still wants to use that socket option. However I am under the impression that 3) should be already possible.
> Ok, excellent, I had not realized this works already.
> I have now also checked
> which uses SO_TIMESTAMP and then should work. I guess this is similar
> to what btmon does.
> For libpcap that leaves
> which needs a fairly simply fix on 32-bit architectures to copy the
> two 32-bit fields
> into the longer pkth.ts fields individually rather than using a memcpy.
> I've added Guy Harris to Cc, he seems to be the maintainer for this file
> according to the git history.
> The same change is needed for
> if there are any remaining users. I can send you a patch if you want.

please send a patch for hcidump if you have the time.



      reply	other threads:[~2020-01-10 17:52 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-10 10:11 [RFC] y2038: HCI_TIME_STAMP with time64 Arnd Bergmann
2020-01-10 15:44 ` Marcel Holtmann
2020-01-10 16:08   ` Arnd Bergmann
2020-01-10 17:52     ` Marcel Holtmann [this message]

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