Wait for child to exit after killing it.

lib/cros_vm_lib.sh

Index: lib/cros_vm_lib.sh
diff --git a/lib/cros_vm_lib.sh b/lib/cros_vm_lib.sh
index d28539c14d5b068fc3003a6be971c8bf64d29c5c..bc4379a47cd5dea911d35ff56054797316eb3c79 100644
--- a/lib/cros_vm_lib.sh
+++ b/lib/cros_vm_lib.sh
@@ -19,6 +19,22 @@ function get_pid() {
   sudo cat "${KVM_PID_FILE}"
 }
 
+# General purpose wait for process to terminate.
+# Incrementally backs off timeouts until it is waiting for 30 seconds and then

[petkov, 2010/12/09 23:01:28]

by 30 you mean 31 -- 1+2+4+8+16? with the exponential back off you'd wait for 16
seconds, then back off to 32 which will be over the threshold.

+# tries to kill -9 before returning.
+# $1 the process id.
+function wait_on_pid() {
+  local timeout=1
+  while ps -p ${1} > /dev/null && [ ${timeout} -le 30 ]; do
+    warn "Process still running, sleeping for ${timeout}"
+    sleep ${timeout}
+    timeout=$((timeout*2))
+  done
+  if ps -p ${1}; then
+    sudo kill -9 ${1}

[petkov, 2010/12/09 23:01:28]

the bonus kill here seems to contradict with the function name. if you do a kill
here then maybe roll the SIGTERM kill into this routine and rename it -- e.g.,
kill_and_wait.

And then, if you try kill -9, you should try to wait again, maybe at least a
second or so.

+  fi
+}
+
 # TODO(rtc): These flags assume that we'll be using KVM on Lucid and won't work
 # on Hardy.
 # $1: Path to the virtual image to start.
@@ -99,6 +115,7 @@ function stop_kvm() {
     if [ -n "${pid}" ]; then
       echo "Killing ${pid}" >&2
       sudo kill ${pid}
+      wait_on_pid ${pid}
       sudo rm "${KVM_PID_FILE}"
     else
       echo "No kvm pid found to stop." >&2