[libvirt] [PATCH 2/8] Add helper for running code in separate namespaces

[Eric Blake]

On 02/17/2014 09:38 AM, Daniel P. Berrange wrote:
> Implement virProcessRunInMountNamespace, which runs callback of type
> virProcessNamespaceCallback in a container namespace. This uses a
> child process to run the callback, since you can't change the mount
> namespace of a thread. This implies that callbacks have to be careful
> about what code they run due to async safety rules.
> 
> Idea by Dan Berrange, based on an initial report by Reco
> <recoverym4n at gmail.com> at
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=732394
> 
> Signed-off-by: Daniel Berrange <berrange at redhat.com>
> Signed-off-by: Eric Blake <eblake at redhat.com>
> ---
>  src/libvirt_private.syms |   1 +
>  src/util/virprocess.c    | 107 +++++++++++++++++++++++++++++++++++++++++++++++
>  src/util/virprocess.h    |  11 +++++
>  3 files changed, 119 insertions(+)

ACK.


> +++ b/src/util/virprocess.c
> @@ -50,6 +50,8 @@
>  #include "virlog.h"
>  #include "virutil.h"
>  #include "virstring.h"
> +#include "virthread.h"

Do we still need virthread.h, or is that leftover from your experiments?


> +
> +/* Run cb(opaque) in the mount namespace of pid.  Return -1 with error
> + * message raised if we fail to run the child, if the child dies from
> + * a signal, or if the child has status 1; otherwise return the exit
> + * status of the child.

Still not quite accurate - we now require that the child has exit status
0 to succeed.  But I'll clean that up when rebasing my virFork cleanups.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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