[PATCH] Ensured SIGQUIT deletes listening UNIX socket files.

[Thibault Charbonnier]

On 4/25/20 6:12 PM, Maxim Dounin wrote:
> A better approach might be to check parent's pid instead, much 
> like we do when handling the changebin signal on unix (see 
> src/os/unix/ngx_process.c).

Great! Thanks for the suggestion. Below is a revised approach for the
patch (also attached to this email) which passes all of the test cases
listed in my previous test file at the start of this thread:

# HG changeset patch
# User Thibault Charbonnier <thibaultcha at me.com>
# Date 1582764433 28800
#      Wed Feb 26 16:47:13 2020 -0800
# Node ID 8d781bac6c4feebb2d1ea3f4e6df76d71f74e43b
# 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 8d781bac6c4f src/core/ngx_connection.c
--- a/src/core/ngx_connection.c	Thu Feb 20 16:51:07 2020 +0300
+++ b/src/core/ngx_connection.c	Wed Feb 26 16:47:13 2020 -0800
@@ -1070,7 +1070,8 @@

         if (ls[i].sockaddr->sa_family == AF_UNIX
             && ngx_process <= NGX_PROCESS_MASTER
-            && ngx_new_binary == 0)
+            && ngx_new_binary == 0
+            && ngx_getppid() != ngx_parent)
         {
             u_char *name = ls[i].addr_text.data + sizeof("unix:") - 1;

diff -r 4f18393a1d51 -r 8d781bac6c4f 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;
         }



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