Re: [Xen-devel] Current LibXL Status

[George Dunlap <dunlapg@xxxxxxxxx>]

On Thu, Nov 19, 2015 at 12:16 PM, Ian Campbell <ian.campbell@xxxxxxxxxx> wrote:
> On Thu, 2015-11-19 at 11:55 +0000, Ian Campbell wrote:
>> On Thu, 2015-11-19 at 11:48 +0000, Ian Campbell wrote:
>> > On Thu, 2015-11-19 at 11:33 +0000, Andrew Cooper wrote:
>> > >
>> > > The majority of those are cases are not appropriate uses of exit().
>> > > AFAIIR, the *only* valid use of exit() in a library is to clean up in
>> > > a
>> > > child process from a library-initiated fork().
>> >
>> > ... or (in this case) in the libxl-save-helper (separate process).
>> >
>> > The only one I can find which isn't one of this is
>> > in libxl__event_disaster, and that is only if the applications (or
>> > language
>> > bindings) haven't provided a suitable disaster callback.
>>
>> Was looking at 4.4, in staging I also see a very odd one in
>> drbd_preresume_async, which isn't obviously in a child process AFAICT.
>>
>> Hongyang, what prevents that exit from killing the whole toolstack
>> process?
>
> I had missed an _async suffix on that function versus the one which was the
> actual callback, it is invoked via drbd_async_call which involves a fork().

So what was the conclusion here?  It looks like we've confirmed that
exit() is only called:

1. In the case of a malloc() failure
2. in libxl-save-helper (a separate process forked by the library)
3. In libxl__event_disaster(), if no callback is provided

Which just leaves #1 as something to be discussed?

(Also, I had suggested making a new thread, but I can't find any
threads continuing this conversation.)

 -George

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel