[PATCH] Ensured SIGQUIT deletes listening UNIX socket files.

[Maxim Dounin]

Hello!

On Wed, Feb 26, 2020 at 04:49:55PM -0800, Thibault Charbonnier wrote:

> # HG changeset patch
> # User Thibault Charbonnier <thibaultcha at me.com>
> # Date 1582764433 28800
> #      Wed Feb 26 16:47:13 2020 -0800
> # Node ID 55ea1a9197a6f28d4da00909e5ea8585f6a08239
> # Parent  4f18393a1d51bce6103ea2f1b2587900f349ba3d
> Ensured SIGQUIT deletes listening UNIX socket files.
> 
> Prior to this patch, the SIGQUIT signal handling (graceful shutdown) did not
> remove UNIX socket files since ngx_master_process_cycle reimplemented
> listening
> socket closings in lieu of using ngx_close_listening_sockets.
> 
> Since ngx_master_process_exit will call the aforementioned
> ngx_close_listening_sockets, we can remove the custom implementation and now
> expect listening sockets to be closed properly by
> ngx_close_listening_sockets
> instead.
> 
> This fixes the trac issue #753 (https://trac.nginx.org/nginx/ticket/753).
> 
> diff -r 4f18393a1d51 -r 55ea1a9197a6 src/os/unix/ngx_process_cycle.c
> --- a/src/os/unix/ngx_process_cycle.c   Thu Feb 20 16:51:07 2020 +0300
> +++ b/src/os/unix/ngx_process_cycle.c   Wed Feb 26 16:47:13 2020 -0800
> @@ -77,12 +77,11 @@
>      u_char            *p;
>      size_t             size;
>      ngx_int_t          i;
> -    ngx_uint_t         n, sigio;
> +    ngx_uint_t         sigio;
>      sigset_t           set;
>      struct itimerval   itv;
>      ngx_uint_t         live;
>      ngx_msec_t         delay;
> -    ngx_listening_t   *ls;
>      ngx_core_conf_t   *ccf;
> 
>      sigemptyset(&set);
> @@ -205,16 +204,6 @@
>              ngx_signal_worker_processes(cycle,
> 
> ngx_signal_value(NGX_SHUTDOWN_SIGNAL));
> 
> -            ls = cycle->listening.elts;
> -            for (n = 0; n < cycle->listening.nelts; n++) {
> -                if (ngx_close_socket(ls[n].fd) == -1) {
> -                    ngx_log_error(NGX_LOG_EMERG, cycle->log,
> ngx_socket_errno,
> -                                  ngx_close_socket_n " %V failed",
> -                                  &ls[n].addr_text);
> -                }
> -            }
> -            cycle->listening.nelts = 0;
> -
>              continue;
>          }
> 

Have you checked what happens during binary upgrade with your 
patch?

Previous attempt to fix this was here:

http://mailman.nginx.org/pipermail/nginx-devel/2016-December/009207.html
http://mailman.nginx.org/pipermail/nginx-devel/2016-December/009208.html

Yet it failed to address binary upgrade case properly, see here:

http://mailman.nginx.org/pipermail/nginx-devel/2016-December/009239.html

-- 
Maxim Dounin
http://mdounin.ru/