[src/trunk]: src/usr.sbin/sup/source - safer way to count kids

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f624441208a3
branches:  trunk
changeset: 763301:f624441208a3
user:      christos <christos%NetBSD.org@localhost>
date:      Wed Mar 16 20:17:00 2011 +0000

description:
- safer way to count kids
- if we are really bombarded with connections, don't bother to fork() and
  converse.

diffstat:

 usr.sbin/sup/source/supfilesrv.c |  29 +++++++++++++++++++++++++----
 1 files changed, 25 insertions(+), 4 deletions(-)

diffs (51 lines):

diff -r 95550fd8b449 -r f624441208a3 usr.sbin/sup/source/supfilesrv.c
--- a/usr.sbin/sup/source/supfilesrv.c  Wed Mar 16 20:15:59 2011 +0000
+++ b/usr.sbin/sup/source/supfilesrv.c  Wed Mar 16 20:17:00 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: supfilesrv.c,v 1.44 2010/10/20 17:05:54 christos Exp $ */
+/*     $NetBSD: supfilesrv.c,v 1.45 2011/03/16 20:17:00 christos Exp $ */
 
 /*
  * Copyright (c) 1992 Carnegie Mellon University
@@ -443,6 +443,14 @@
                        (void) servicekill();
                        continue;
                }
+               /*
+                * If we are being bombarded, don't even spend time forking
+                * or conversing
+                */
+               if (nchildren >= maxchildren + 5) {
+                       (void) servicekill();
+                       continue;
+               }
                sigemptyset(&nset);
                sigaddset(&nset, SIGCHLD);
                sigprocmask(SIG_BLOCK, &nset, &oset);
@@ -481,10 +489,23 @@
 chldsig(int snum __unused)
 {
        int w;
+       pid_t pid;
 
-       while (wait3((int *) &w, WNOHANG, (struct rusage *) 0) > 0) {
-               if (nchildren)
-                       nchildren--;
+       while ((pid = waitpid(-1, &w, WNOHANG)) > 0) {
+               if (kill(pid, 0) == -1)
+                       switch (errno) {
+                       case ESRCH:
+                               if (nchildren == 0)
+                                       logerr("no children but pid %jd\n",
+                                           (intmax_t)pid);
+                               nchildren--;
+                               break;
+                       default:
+                               logerr("killing pid %jd: (%s)\n", (intmax_t)
+                                   pid, strerror(errno));
+                               break;
+                       }
+
        }
 }
 /*****************************************