libxl: treat "dying" domains as destroyed

Rename the DOMAIN_DESTROY event to DOMAIN_DEATH and have it trigger
when the domain goes into the state indicated by the domaininfo flag
"dying".

This fixes a race which could leak a daemonised xl process, which
would have ignored the domain becoming "dying" and would then wait
forever to be told the domain was destroyed.

After the domain becomes "dying" we can't generate an event when it is
actually destroyed because xenstored will eat the relevant
VIRT_DOM_EXC virq and not generate an @releaseDomain, since xenstored
discards its own record of the domain's existence as soon as it sees
the domain "dying" and will not trigger @releaseDomain watches for
domains it knows nothing about.  Arguably this is a bug in xenstored,
and the whole @releaseDomain machinery is rather poor, but let us not
fix that now.

Anyway, xl does not really want to know when the domain is ultimately
destroyed.  It is enough for xl to know that it is on the way out, in
the "dying" state (which leads later to destruction by Xen).

Also fix a bug where domain_death_xswatch_callback might read one
domain beyond the valid data in its domaininfos array, by correctly
ordering the checks for empty domain list, end of domain list, and our
domain being missing.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Tested-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>

0 files changed, 0 insertions, 0 deletions