[Kimchi-devel] [PATCH] Github bug #326: run_command: killing all children processes

[Daniel Barboza]

From: Daniel Henrique Barboza <danielhb at linux.vnet.ibm.com>

The subprocess.kill() call does not handle well the created children
of the process created by the Popen() call. In some cases (for
example, the mount command) the parent processes creates children
processes that aren't killed, leaving the parent thread hanging out
in an infinite loop waiting for kill() to finish.

An attempt was made using the os.killpg() call, but to no success.
Using psutils facilities to kill all the children before killing the
opened process was easier and clearer than the alternatives (opening
a new thread and trying to kill the thread, for example).

Signed-off-by: Daniel Henrique Barboza <danielhb at linux.vnet.ibm.com>
---
 src/kimchi/utils.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/kimchi/utils.py b/src/kimchi/utils.py
index a1410c0..6be1c04 100644
--- a/src/kimchi/utils.py
+++ b/src/kimchi/utils.py
@@ -23,6 +23,7 @@
 
 import cherrypy
 import os
+import psutil
 import re
 import subprocess
 import urllib2
@@ -137,8 +138,16 @@ def run_command(cmd, timeout=None):
     timeout is a float number in seconds.
     timeout default value is None, means command run without timeout.
     """
+    # subprocess.kill() can leave descendants running
+    # and halting the execution. Using psutil to
+    # get all descendants from the subprocess and
+    # kill them recursively.
     def kill_proc(proc, timeout_flag):
         try:
+            parent = psutil.Process(proc.pid)
+            for child in parent.get_children(recursive=True):
+                child.kill()
+            # kill the process after no children is left
             proc.kill()
         except OSError:
             pass
-- 
1.8.3.1