Fwd: [PATCH]: unlink legacy unix socket when unit starts
lei shan
shanlei at asiainfo.com
Fri Apr 29 08:37:22 UTC 2022
---------- Forwarded message ---------
From: lei shan <shanlei at asiainfo.com>
Date: Fri, 29 Apr 2022, 16:36
Subject: Re: [PATCH]: unlink legacy unix socket when unit starts
To: Александр Поволоцкий <tarkhil at over.ru>
I am working on it, just as control socket did.
The idea is when the main process create the pipe, it stores the socket in
runtime' listening_conntions, then remove it in runtime_exit of the main
process.
The cleaning can't be done by router is :
The Unix socket owned by root user
On Fri, 29 Apr 2022, 14:09 Александр Поволоцкий, <tarkhil at over.ru> wrote:
> No patch will remove pipe on kill -9. We need to implement the logic used
> for control socket.
> On 29.04.2022 8:34, lei shan wrote:
>
> Hello guys,
>
> The process may crash, or other may misconfig and cause the file
> confliction.
> But at least, unit should remove the pipe file on exit,as it already does
> to the control pipe.
>
> So a patch should remove the Unix pipe on stop , instead of on startup.
>
> Can we agree on this?
>
> Thanks & Best Regards
>
>
> On Wed, 27 Apr 2022, 05:45 Oleg A. Mamontov, <oleg at mamontov.net> wrote:
>
>> On Wed, Apr 27, 2022 at 05:11:26AM +1000, Scott van Kalken wrote:
>> >This will work well for cases where unit shuts down gracefully. If unit
>> does
>> >not shut down gracefully, then i think you will have the same startup
>> problem.
>> >
>> >It’s a good point about the TCP socket.
>>
>> It seems the key point is the way to check on startup whether the unix
>> socket is stale or currently in use and then to decide remove it and
>> re-create or just fail the start, isn't it?
>>
>> >On Tue, 26 Apr 2022 at 11:50 am, <shanlei at asiainfo.com> wrote:
>> >
>> > I have reconsided the situation:
>> > compare to TCP sockets, if a TCP bind fails, we know other programs
>> are
>> > using the socket ,the ops team then fix the mis-configured port
>> number,
>> > change unit or other programs.
>> > the unix socket should behave similarly.
>> > the diffrence is when a tcp server is done, the socket is recycled by
>> > system, while the unix socket file is left in disk, which block
>> "unit"'s
>> > next boot.
>> > may the idea patch is to unlink the unix socket file on shutdown,
>> > instead of startup?
>> >
>> >
>> > On 2022-04-25 14:38，Scott van Kalken wrote：
>> > > What if it were a command line option to delete on start? This way
>> you
>> > > preserve the existing behaviour while introducing the desired
>> > > behaviour. It’s up to the user / admin to decide if they want to
>> > > “force delete” as an example.
>> > >
>> > > On Mon, 25 Apr 2022 at 4:33 pm, <shanlei at asiainfo.com> wrote:
>> > >
>> > >> I know the concern, that if we misconfigure the socket file, other
>> > >> file
>> > >> may be deleted accidentally.
>> > >> But if the program wont delete the file, bind will fail , that
>> means
>> > >> we
>> > >> have to delete the file manually before every start. that not a
>> good
>> > >>
>> > >> option to maintain a system.
>> > >>
>> > >> 在 2022-04-24 18:05，Александр Поволоцкий
>> > >> wrote：
>> > >>> Unlink socket that can be in use? I think it's not a good idea.
>> > >>>
>> > >>> On 24.04.2022 12:25, shanlei at asiainfo.com wrote:
>> > >>>>
>> > >>>> hello,guys,
>> > >>>>
>> > >>>> We found if we add a unix socket listener, the file was left in
>> > >> disk
>> > >>>> when unit got shutdown.
>> > >>>> If the unit starts again and load configuration from its state
>> > >> folder,
>> > >>>> it would fail with error msg "file exists",
>> > >>>> so We think the proper process is to "delete the legacy unix
>> > >> socket
>> > >>>> before start", and we present following patch:
>> > >>>>
>> > >>>>
>> > >>>> # HG changeset patch
>> > >>>> # User stdanley <shanlei at asiainfo.com>
>> > >>>> # Date 1650792235 -28800
>> > >>>> # Sun Apr 24 17:23:55 2022 +0800
>> > >>>> # Node ID 29738840c393f12c7d7aa8f3959ed1655b39cd4d
>> > >>>> # Parent 8e06a879600e83af11345d023c53c2ca445cf82c
>> > >>>> unlink legacy unix socket file before binding.
>> > >>>>
>> > >>>> diff -r 8e06a879600e -r 29738840c393 src/nxt_main_process.c
>> > >>>> --- a/src/nxt_main_process.c Tue Apr 12 04:16:00 2022 +0100
>> > >>>> +++ b/src/nxt_main_process.c Sun Apr 24 17:23:55 2022 +0800
>> > >>>> @@ -1142,6 +1142,15 @@
>> > >>>> }
>> > >>>>
>> > >>>> #endif
>> > >>>> +#if (NXT_HAVE_UNIX_DOMAIN)
>> > >>>> +
>> > >>>> + if (sa->u.sockaddr.sa_family == AF_UNIX
>> > >>>> + && sa->type == SOCK_STREAM
>> > >>>> + && sa->u.sockaddr_un.sun_path[0] != '\0') {
>> > >>>> +
>> > >>>> + (void) unlink(sa->u.sockaddr_un.sun_path);
>> > >>>> +}
>> > >>>> +#endif
>> > >>>>
>> > >>>> if (bind(s, &sa->u.sockaddr, sa->socklen) != 0) {
>> > >>>> err = nxt_errno;
>> > >>>> _______________________________________________
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>>
>> >_______________________________________________
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>>
>> --
>> Cheers,
>> Oleg A. Mamontov
>>
>> mailto: oleg at mamontov.net
>>
>> skype: lonerr11
>> cell: +7 (903) 798-1352
>> _______________________________________________
>> unit mailing list -- unit at nginx.org
>> To unsubscribe send an email to unit-leave at nginx.org
>>
>
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