[PATCH 4/7] NetTestSlave: add graceful termination to kill_command

[Jan Tluka]

I added graceful parameter to kill_command. When it is set to True
the slave first tries to interrupt the command using SIG_INT. Then it
waits 5 seconds and checks if the process is still alive using pid_exists().
When the command does not terminate after this period it is killed by
SIG_KILL.

This is basically needed if we want to keep the output of a command
that timeouts. When killed (not interrupted) the command's output is
lost and never logged.

Signed-off-by: Jan Tluka 
---
 lnst/Slave/NetTestSlave.py | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/lnst/Slave/NetTestSlave.py b/lnst/Slave/NetTestSlave.py
index 3b8bf79..057deea 100644
--- a/lnst/Slave/NetTestSlave.py
+++ b/lnst/Slave/NetTestSlave.py
@@ -439,11 +439,29 @@ class SlaveMethods:

return res

-    def kill_command(self, id):
+    def kill_command(self, id, graceful=False):
         cmd = self._command_context.get_cmd(id)
         if cmd is not None:
             if not cmd.get_result_sent():
-                cmd.kill(None)
+                if graceful:
+                    check=0
+                    cmd.set_gracefully_killed()
+                    cmd.interrupt(None)
+                    while check < 5:
+                        sleep(1)
+                        if not cmd.pid_exists():
+                            break
+                        check += 1
+
+                    if cmd.pid_exists():
+                        logging.debug("Graceful termination timeout, killing")
+                        cmd.kill(None)
+                    else:
+                        return None
+                else:
+                    cmd.set_gracefully_killed(False)
+                    cmd.kill(None)
+
                 result = cmd.get_result()
                 cmd.set_result_sent()
                 return result