[Kimchi-devel] [PATCH] [Kimchi 1/1] Fix issue #1170: ERROR:KCHVM0090E: Unable to create a password-less libvirt connection to the remote libvirt daemon

[Fu.Lin]

Long ago, I submitted an issue: 
https://github.com/kimchi-project/kimchi/issues/1170 ...

Test by following script:

    import subprocess
    import os
    import time

    def _check_remote_libvirt_conn(remote_host,
             user='root', transport='ssh'):

         FNULL = open(os.devnull, 'w')
         dest_uri = 'qemu+%s://%s@%s/system' % (transport, user,
    remote_host)
         cmd = ['virsh', '-c', dest_uri, 'list']
         proc = subprocess.Popen(cmd, stdout=FNULL, stderr=FNULL,
                 shell=True, preexec_fn=os.setsid)
         timeout = 0
         while proc.poll() is None:
             time.sleep(1)
             timeout += 1
             if timeout == 5:
                 print("killed")
                 os.killpg(os.getpgid(proc.pid), signal.SIGTERM)

    if __name__ == '__main__':
         _check_remote_libvirt_conn('localhost')

`proc` is timeout every time although the connection is normal tested by 
`virsh -c <uri>` list


The following is the reason of changing(From Python Document 2.7.14):

  Do not use stdout=PIPE or stderr=PIPE with this function as that can 
deadlock based on the child process output volume. Use Popen with the 
communicate() method when you need pipes.

  Using shell=True can be a security hazard. See the warning under 
Frequently Used Arguments for details.

At the same time, if not change, it does not work.


diff --git a/model/vms.py b/model/vms.py
index 6da4f3b..92e771f 100644
--- a/model/vms.py
+++ b/model/vms.py
@@ -1885,10 +1885,11 @@ class VMModel(object):
      def _check_remote_libvirt_conn(self, remote_host,
                                     user='root', transport='ssh'):

+        FNULL = open(os.devnull, 'w')
          dest_uri = 'qemu+%s://%s@%s/system' % (transport, user, 
remote_host)
          cmd = ['virsh', '-c', dest_uri, 'list']
-        proc = subprocess.Popen(cmd, stdout=subprocess.PIPE,
-                                shell=True, preexec_fn=os.setsid)
+        proc = subprocess.Popen(cmd, stdout=FNULL, stderr=FNULL,
+                                shell=False, preexec_fn=os.setsid)
          timeout = 0
          while proc.poll() is None:
              time.sleep(1)

-- 
Regards
River (Fu.Lin)

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