Re: select()ing on a pcap descriptor in Solaris

[Guy Harris <guy () alum mit edu>]

On Aug 14, 2014, at 1:34 PM, Fernando Gont <fernando () gont com ar> wrote:

> While trying to select() on a pcap descriptor in solaris

Which version?  Solaris 11 (in which pcap descriptors should refer to BPF devices), or earlier (in which pcap 
descriptors should refer to DLPI STREAMS devices)?

> I found the following:
>
> 1) It seems that pcap descriptors are never readable or writeable. (--
> This is different from *BSD and Linux, where at least you seem to be
> able to check for readability)
>
> 2) It would seem that even trying to select() on such descriptors causes
> trouble. For example, I get a kind of random "Bad file number" error
> from select when I try to check for readability/writeability.

I wouldn't expect that prior to Solaris 11 - select() and poll() Just Work on STREAMS devices, as I remember.

It could, however, be that Sun^WOracle screwed up with BPF; unfortunately, Solaris 11 is ClosedSolaris, so I can't just 
look at the source and see what they did wrong.

I'll try this on my Solaris 11 virtual machine.

> Is the above assessment correct? Should I not even try to call select()
> on pcap descriptors in Solaris?

If they screwed up on Solaris 11, you probably shouldn't try to call select(); instead, you should try to call Oracle 
and report this as a bug (and tell them that, if they fix this, they should fix it so that if you have a timeout set 
with BIOCSRTIMEOUT, the timer should start as soon as a select() or poll() is done, so that, when the timeout expires, 
it can report the descriptor as readable - the original BPF didn't do that, and all the *BSDs and OS X eventually fixed 
it).
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