[libvirt] Some problem with the save function

[Paolo Bonzini]

On 09/18/2009 03:09 AM, Charles Duffy wrote:
> Daniel P. Berrange wrote:
>> Hmm, bad error message :-( We might also need todo a chown()
>> in the restore path to allow QEMU to read it. NB there is no
>> compatability between QEMU version, so if you have upgraded
>> your install of QEMU between the time you saved & restored
>> it is very likely to crash & burn.
>
> How difficult would it be to set up named pipes for save and restore
> operations, and splice from those pipes to the actual files on the
> libvirtd side? Seems much preferable from a security perspective to
> chown'ing things around, and (unlike pipes set up ahead of time with
> pipe() and friends) shouldn't be disrupted by a libvirtd restart.

For a recent enough QEMU, you could also use the 
migrate-to-file-descriptor functionality which uses SCM_RIGHTS.  It is 
in QEMU 0.12 only, but since the plumbing is in 0.11 too we could ask 
for a backport.

Paolo