Serge,
See below. The open program opens it and gets file ID 3 as one
would expect. Whilst running this the VM is outputting the not permitted
message on the same device. So root can open but libvirt cannot!
root@vmserver:/tmp# lsusb
Bus 008 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 003: ID 04a9:1717 Canon, Inc. MP510
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@vmserver:/tmp# ./open /dev/bus/usb/003/003
open returned 3
root@vmserver:/tmp# ./open /dev/bus/usb/003/003
open returned 3
root@vmserver:/tmp#
Regards
Roy
On 29/06/2011 05:39, Serge Hallyn wrote:
> Let's see if we can get root in general to fail to open this. First
> paste the following into 'open.c' (without the '========' lines), and
> then compile that using 'make open'.
>
> ===============================================================
> #include<stdio.h>
> #include<stdlib.h>
> #include<sys/types.h>
> #include<sys/stat.h>
> #include<fcntl.h>
>
>
> int main(int argc, char *argv[])
> {
> int ret;
>
> if (argc< 2)
> {
> printf("try %s /dev/bus/usb/001/013\n", argv[0]);
> exit(1);
> }
> ret = open(argv[1], O_RDWR|O_NONBLOCK);
> printf("open returned %d\n", ret);
> close(ret);
> }
> ===============================================================
>
> Plug in the printer and try starting the VM with libvirt. Look in the
> log file to get the pathname it is trying to use. Then run open with
> that file as argument. For instance if you see
>
> /dev/bus/usb/001/004: Operation not permitted
>
> then try
>
> sudo ./open /dev/bus/usb/001/004
>
> If it says it returned a positive number, then it succeeded in opening
> it. If it returned -1, then we know that in fact root can't open that
> device, and it isn't just libvirt.
>
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https://bugs.launchpad.net/bugs/787091
Title:
Unable to use USB device in KVM quest
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