Wait for child to exit after killing it.

lib/cros_vm_lib.sh

 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
 # Common vm functions for use in crosutils.
 
 DEFINE_string kvm_pid "" \
   "Use this pid file.  If it exists and is set, use the vm specified by pid."
 DEFINE_boolean no_graphics ${FLAGS_FALSE} "Runs the KVM instance silently."
 DEFINE_boolean persist "${FLAGS_FALSE}" "Persist vm."
 DEFINE_boolean snapshot ${FLAGS_FALSE} "Don't commit changes to image."
 DEFINE_integer ssh_port 9222 "Port to tunnel ssh traffic over."
 DEFINE_string vnc "" "VNC Server to display to instead of SDL."
 
 KVM_PID_FILE=/tmp/kvm.$$.pid
 LIVE_VM_IMAGE=
 
 function get_pid() {
   sudo cat "${KVM_PID_FILE}"
 }
 
+# General purpose blocking kill on a pid.
+# This function sends a specified kill signal [0-9] to a pid and waits for it
+# die up to a given timeout.  It exponentially backs off it's timeout starting
+# at 1 second.
+# $1 the process id.
+# $2 signal to send (-#).
+# $3 max timeout in seconds.
+# Returns 0 on success.
+function blocking_kill() {
+  local timeout=1
+  sudo kill -$2 $1
+  while ps -p $1 > /dev/null && [ ${timeout} -le $3 ]; do
+    warn "Process still running, sleeping for ${timeout}"
+    sleep ${timeout}
+    timeout=$((timeout*2))
+  done
+  ! ps -p ${1} > /dev/null

[petkov, 2010/12/09 23:37:17]

don't know bash enough -- are you sure ! switched exit code 0 to non-zero and
vice-versa?

+}
+
 # TODO(rtc): These flags assume that we'll be using KVM on Lucid and won't work
 # on Hardy.
 # $1: Path to the virtual image to start.
 function start_kvm() {
   # Override default pid file.
   [ -n "${FLAGS_kvm_pid}" ] && KVM_PID_FILE=${FLAGS_kvm_pid}
   if [ -e "${KVM_PID_FILE}" ]; then
     local pid=$(get_pid)
     # Check if the process exists.
     if ps -p ${pid} > /dev/null ; then
@@ skipping 59 matching lines @@
 
 function stop_kvm() {
   if [ "${FLAGS_persist}" -eq "${FLAGS_TRUE}" ]; then
     echo "Persist requested.  Use --ssh_port ${FLAGS_ssh_port} " \
       "--kvm_pid ${KVM_PID_FILE} to re-connect to it." >&2
   else
     echo "Stopping the KVM instance" >&2
     local pid=$(get_pid)
     if [ -n "${pid}" ]; then
       echo "Killing ${pid}" >&2
-      sudo kill ${pid}
+      blocking_kill ${pid} 1 16 || blocking_kill 9 1
       sudo rm "${KVM_PID_FILE}"
     else
       echo "No kvm pid found to stop." >&2
       return 1
     fi
   fi
 }