bug#53191: 29.0.50; file-notify-add-watch fails for socket files on MacOS

[Troy de Freitas <me@ntdef.com>]

Hi Michael, 

Thanks for looking into this. Actually, all I wanted was to be able to see when the socket file was deleted. 

Regards,
Troy de Freitas

> On Jan 15, 2022, at 8:45 AM, Michael Albinus <michael.albinus@gmx.de> wrote:
> 
> Michael Albinus <michael.albinus@gmx.de> writes:
> 
> Hi Troy,
> 
>> Thanks for the report. The incrimed behavior is due to unconditional
>> using of the EVFILT_VNODE filter, calling EV_SET in
>> Fkqueue_add_watch. This requires a file descriptor.
>> 
>> I'll investigate, whether another filter, like EVFILT_READ, is better
>> suited for sockets, using a sockfd. This might take some days, though.
> 
> I'm sorry, but it seems that EV_SET requires a file descriptor. I
> couldn't find a way to pass the socket file otherwise but via open(),
> which doesn't work on *BSD-like systems, as you have analyzed.
> 
> What is your use case to supervise a socket file? You can't get more
> information except that the file is deleted. And this you get also if
> you monitor the parent directory.
> 
>>> - Troy
> 
> Best regards, Michael.