[libvirt-users] Using unix-type channel ....

[Jean-Pierre Ribeauville]

Hi,

I'm trying to use unix-type channel to send/receive datas between host and guest .

Here are the steps I follow :

1) Adding these lines to expose a channel unix type to my guest
 <channel type='unix'>
      <source mode='bind' path='/var/lib/libvirt/qemu/omnivision_1.agent'/>
      <target type='virtio' name='org.qemu.guest_agent.0'/>
      <alias name='channel0'/>
      <address type='virtio-serial' controller='0' bus='0' port='2'/>
    </channel>


2) the VM_Orion-1 Guest, exposing a channel "unix" omnivision_1.agent  is started, then netstat shows these new things :

netstat -apn | grep qemu
unix  2      [ ACC ]     STREAM     LISTENING     37214  19124/qemu-kvm      /var/lib/libvirt/qemu/VM_Orion-1.monitor
unix  2      [ ACC ]     STREAM     LISTENING     37219  19124/qemu-kvm      /var/lib/libvirt/qemu/omnivision_1.agent
unix  3      [ ]         STREAM     CONNECTED     37242  19124/qemu-kvm      /var/lib/libvirt/qemu/omnivision_1.agent
unix  3      [ ]         STREAM     CONNECTED     37240  19124/qemu-kvm      /var/lib/libvirt/qemu/VM_Orion-1.monitor

3) I start  , on the host , a simple test in order to send datas to the guest:

.....
     sock = socket(AF_UNIX, SOCK_STREAM, 0);
     if (sock < 0) {
         perror("opening stream socket");
         return(1);
     }
     server.sun_family = AF_UNIX;
     strcpy(server.sun_path, argv[1]);

     printf("connecting to socket number : %d \n",sock);
     fflush(stdout);

     if (connect(sock, (struct sockaddr *) &server, sizeof(struct sockaddr_un)) < 0) {
         close(sock);
         perror("connecting stream socket");
         return(1);
     }
     printf("writing data on stream socket");
     if (write(sock, DATA, sizeof(DATA)) < 0)
         perror("writing on stream socket");
     close(sock);
.....

4) invoking  > test "/var/lib/libvirt/qemu/omnivision_1.agent"

then I got  :

connecting to socket number : 3
writing data on stream socket

and following netstat result :

netstat -apn | grep qemu
unix  2      [ ACC ]     STREAM     LISTENING     39348  20587/qemu-kvm      /var/lib/libvirt/qemu/VM_Orion-1.monitor
unix  2      [ ACC ]     STREAM     LISTENING     39353  20587/qemu-kvm      /var/lib/libvirt/qemu/omnivision_1.agent
unix  2      [ ]         STREAM     CONNECTING    0      -                   /var/lib/libvirt/qemu/omnivision_1.agent
unix  3      [ ]         STREAM     CONNECTED     39375  20587/qemu-kvm      /var/lib/libvirt/qemu/omnivision_1.agent
unix  3      [ ]         STREAM     CONNECTED     39373  20587/qemu-kvm      /var/lib/libvirt/qemu/VM_Orion-1.monitor



5) if I try to re-invoke test "/var/lib/libvirt/qemu/omnivision_1.agent"  then :

netstat -apn | grep qemu
tcp        0      0 127.0.0.1:5902              0.0.0.0:*                   LISTEN      20587/qemu-kvm
tcp        0      0 127.0.0.1:5902              127.0.0.1:57772             ESTABLISHED 20587/qemu-kvm
unix  2      [ ACC ]     STREAM     LISTENING     39348  20587/qemu-kvm      /var/lib/libvirt/qemu/VM_Orion-1.monitor
unix  2      [ ACC ]     STREAM     LISTENING     39353  20587/qemu-kvm      /var/lib/libvirt/qemu/omnivision_1.agent
unix  2      [ ]         STREAM     CONNECTING    0      -                   /var/lib/libvirt/qemu/omnivision_1.agent
unix  2      [ ]         STREAM     CONNECTING    0      -                   /var/lib/libvirt/qemu/omnivision_1.agent
unix  3      [ ]         STREAM     CONNECTED     39375  20587/qemu-kvm      /var/lib/libvirt/qemu/omnivision_1.agent
unix  3      [ ]         STREAM     CONNECTED     39373  20587/qemu-kvm      /var/lib/libvirt/qemu/VM_Orion-1.monitor


on the guest side , I try to retrieve datas sent by host , by using this kind of thing  :

...
int fd = open("/dev/virtio-ports/org.qemu.guest_agent.0", O_RDWR | O_NONBLOCK);
    ssize_t size = read(fd, &buffer, 100);
...


As you can imagine , I never receive any data from the host .


Is it the right way to use this "unix-type"  channel ?

Thx for your patience.

Regards,

J.P. Ribeauville


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jpribeauville at axway.com<mailto:jpribeauville at axway.com>
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