[libvirt] [PATCH 2/3] qemu: Fix QMP Capabability Probing Failure

[Daniel P. Berrange]

On Mon, Nov 26, 2012 at 03:17:13PM +0100, Viktor Mihajlovski wrote:
> QMP Capability probing will fail if QEMU cannot bind to the
> QMP monitor socket in the qemu_driver->libDir directory.
> That's because the child process is stripped of all
> capabilities and this directory is chown'ed to the configured
> QEMU user/group (normally qemu:qemu) by the QEMU driver.
> 
> To prevent this from happening, the driver startup will now pass
> the QEMU uid and gid down to the capability probing code.
> All capability probing invocations of QEMU will be run with
> the configured QEMU uid instead of libvirtd's.
> 
> Furter, the pid file handling is moved to libvirt, as QEMU
> cannot write to the qemu_driver->runDir (root:root). This also
> means that the libvirt daemonizing must be used.
> 
> Signed-off-by: Viktor Mihajlovski <mihajlov at linux.vnet.ibm.com>
> ---
>  src/qemu/qemu_capabilities.c | 88 ++++++++++++++++++++++++++++++++++----------
>  src/qemu/qemu_capabilities.h |  7 +++-
>  src/qemu/qemu_driver.c       |  4 +-
>  3 files changed, 76 insertions(+), 23 deletions(-)

ACK,

A nice side effect of this is that the traditional non-QMP based
QEMU probing also now runs unprivileged

Daniel
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