[PATCH v2 3/6] use internal killtree, to not leave running sleep commands behind

[Hubert Kario]

Just killing the sub shell running won't send kill signal to
running commands, use treekill to kill all processes in process
tree. Also gets rid of the ugly bash reports of tasks terminated
in background.

Signed-off-by: Hubert Kario 
---
 src/synchronisation.sh | 36 ++++++++++++++++++++++++++++++++----
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/src/synchronisation.sh b/src/synchronisation.sh
index 685a758..e782481 100644
--- a/src/synchronisation.sh
+++ b/src/synchronisation.sh
@@ -31,6 +31,32 @@ if [ ${ret:-0} -ne 4 ]; then
     exit 1
 fi

+# add ability to kill whole process tree
+# unfortunately, because we're running inside bash script, we can't
+# use the simple solution of process groups and `kill -s SIG -$pid`
+# usage: __INTERNAL_killtree PID [SIGNAL]
+# returns first failed kill return code or 0 if all returned success
+__INTERNAL_killtree() {
+    local _pid=$1
+    if [[ ! -n $_pid ]]; then
+        return 2
+    fi
+    local _sig=${2:-TERM}
+    local _ret=
+    kill -s SIGSTOP ${_pid} || : # prevent parent from forking
+    local _children=$(pgrep -P ${_pid})
+    local _pret=$?
+    if [[ $_pret -ne 0 && $_pret -ne 1 ]]; then
+        return 4
+    fi
+    for _child in $_children; do
+        __INTERNAL_killtree ${_child} ${_sig} || _ret=${_ret:-$?}
+    done
+    kill -s ${_sig} ${_pid} || _ret=${_ret:-$?}
+    kill -s SIGCONT ${_pid} || : # allow for signal delivery to parent
+    return ${_ret:-0}
+}
+
 : <<'=cut'
 =pod

@@ -155,18 +181,20 @@ rlWaitForSocket(){
     done ) &
     local netstat_pid=$!

-    ( sleep $timeout && kill -HUP -$netstat_pid ) 2>/dev/null &
+    ( sleep $timeout; __INTERNAL_killtree $netstat_pid SIGKILL) 2>/dev/null &
     local watcher=$!

-    wait $netstat_pid
+    wait $netstat_pid 2> /dev/null
     local ret=$?
     if [[ $ret -eq 0 ]]; then
-        kill -s SIGKILL $watcher 2>/dev/null
+        __INTERNAL_killtree $watcher SIGKILL 2>/dev/null
+        wait $watcher 2> /dev/null
         rlLogInfo "rlWaitForSocket: Socket opened!"
         return 0
     else
         if [[ $ret -eq 1 ]]; then
-            kill -s SIGKILL $watcher 2>/dev/null
+            __INTERNAL_killtree $watcher SIGKILL 2>/dev/null
+            wait $watcher 2> /dev/null
             rlLogWarning "rlWaitForSocket: PID terminated!"
         else
             rlLogWarning "rlWaitForSocket: Timeout elapsed"