[src/trunk]: src/etc Prevent waiting for processes to exit forever by introdu...

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

details:   https://anonhg.NetBSD.org/src/rev/2316b7622cd1
branches:  trunk
changeset: 1008922:2316b7622cd1
user:      christos <christos%NetBSD.org@localhost>
date:      Sun Apr 05 21:03:08 2020 +0000

description:
Prevent waiting for processes to exit forever by introducing _rc_kill_ntries,
which if set, will SIGKILL the processes that did not die yet.

diffstat:

 etc/rc.subr |  59 +++++++++++++++++++++++++++++++++++++++++++----------------
 1 files changed, 43 insertions(+), 16 deletions(-)

diffs (94 lines):

diff -r 8c3fa57e76d9 -r 2316b7622cd1 etc/rc.subr
--- a/etc/rc.subr       Sun Apr 05 20:59:38 2020 +0000
+++ b/etc/rc.subr       Sun Apr 05 21:03:08 2020 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: rc.subr,v 1.103 2018/09/23 23:02:39 kre Exp $
+# $NetBSD: rc.subr,v 1.104 2020/04/05 21:03:08 christos Exp $
 #
 # Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
 # All rights reserved.
@@ -43,6 +43,7 @@
 _rc_original_stdout_fd=
 _rc_original_stderr_fd=
 _rc_postprocessor_fd=
+_rc_kill_ntries=
 "
 
 #
@@ -313,35 +314,61 @@
 }
 
 #
+# kill_pids signal pid [pid ...]
+#      kills the given pids with signal. 
+#      returns the list of pids killed successfully.
+#
+kill_pids()
+{
+       local signal=$1
+       shift
+       local list="$@"
+       local j=
+       local nlist=
+       for j in $list; do
+               if kill -$signal $j 2>/dev/null; then
+                       nlist="${nlist}${nlist:+ }$j"
+               fi
+       done
+       echo $nlist
+}
+
+#
 # wait_for_pids pid [pid ...]
 #      spins until none of the pids exist
+#      if _rc_kill_ntries is set and exceeded, it SIGKILLS the remaining
+#      pids
 #
 wait_for_pids()
 {
-       _list="$@"
-       if [ -z "$_list" ]; then
+       local ntries=0
+       local prefix=
+       local list="$@"
+
+       if [ -z "$list" ]; then
                return
        fi
-       _prefix=
+
        while true; do
-               _nlist="";
-               for _j in $_list; do
-                       if kill -0 $_j 2>/dev/null; then
-                               _nlist="${_nlist}${_nlist:+ }$_j"
-                       fi
-               done
-               if [ -z "$_nlist" ]; then
+               local nlist=$(kill_pids 0 $list)
+               if [ -z "$nlist" ]; then
                        break
                fi
-               if [ "$_list" != "$_nlist" ]; then
-                       _list=$_nlist
-                       echo -n ${_prefix:-"Waiting for PIDS: "}$_list
-                       _prefix=", "
+               if [ "$list" != "$nlist" ]; then
+                       list=$nlist
+                       echo -n ${prefix:-"Waiting for PIDS: "}$list
+                       prefix=", "
                fi
                # We want this to be a tight loop for a fast exit
                sleep 0.05
+               ntries=$((ntries + 1))
+               if [ -n "${_rc_kill_ntries}" ]; then
+                       if [ ${ntries} -gt ${_rc_kill_ntries} ]; then
+                               kill_pids 9 $list > /dev/null
+                       fi
+               fi
        done
-       if [ -n "$_prefix" ]; then
+       if [ -n "$prefix" ]; then
                echo "."
        fi
 }