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Libvirt native C API and daemons
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Eric Blake 4221d64fcb event: don't let old-style events clobber per-domain events
Right now, the older virConnectDomainEventRegister (takes a
function pointer, returns 0 on success) and the newer
virConnectDomainEventRegisterID (takes an eventID, returns a
callbackID) share the underlying implementation (the older
API ends up consuming a callbackID for eventID 0 under the
hood).  We implemented that by a lot of copy and pasted
code between object_event.c and domain_event.c, according to
whether we are dealing with a function pointer or an eventID.
However, our copy and paste is not symmetric.  Consider this
sequence:

id1 = virConnectDomainEventRegisterAny(conn, dom,
   VIR_DOMAIN_EVENT_ID_LIFECYCLE,
   VIR_DOMAIN_EVENT_CALLBACK(callback), NULL, NULL);
virConnectDomainEventRegister(conn, callback, NULL, NULL);
virConnectDomainEventDeregister(conn, callback);
virConnectDomainEventDeregsiterAny(conn, id1);

the first three calls would succeed, but the third call ended
up nuking the id1 callbackID (the per-domain new-style handler),
then the fourth call failed with an error about an unknown
callbackID, leaving us with the global handler (old-style) still
live and receiving events.  It required another old-style
deregister to clean up the mess.  Root cause was that
virDomainEventCallbackList{Remove,MarkDelete} were only
checking for function pointer match, rather than also checking
for whether the registration was global.

Rather than playing with the guts of object_event ourselves
in domain_event, it is nicer to add a mapping function for the
internal callback id, then share common code for event removal.
For now, the function-to-id mapping is used only internally;
I thought about whether a new public API to let a user learn
the callback would be useful, but decided exposing this to the
user is probably a disservice, since we already publicly
document that they should avoid the old style, and since this
patch already demonstrates that older libvirt versions have
weird behavior when mixing old and new styles.

And like all good bug fix patches, I enhanced the testsuite,
validating that the changes in tests/ expose the failure
without the rest of the patch.

* src/conf/object_event.c (virObjectEventCallbackLookup)
(virObjectEventStateCallbackID): New functions.
(virObjectEventCallbackLookup): Use helper function.
* src/conf/object_event_private.h (virObjectEventStateCallbackID):
Declare new function.
* src/conf/domain_event.c (virDomainEventStateRegister)
(virDomainEventStateDeregister): Let common code handle the
complexity.
(virDomainEventCallbackListRemove)
(virDomainEventCallbackListMarkDelete)
(virDomainEventCallbackListAdd): Drop unused functions.
* tests/objecteventtest.c (testDomainCreateXMLMixed): New test.

Signed-off-by: Eric Blake <eblake@redhat.com>
2014-01-07 09:12:10 -07:00
.gnulib@d18d1b8023 build: fix bootstrap with older autoconf 2014-01-06 14:55:10 -07:00
build-aux maint: enforce comma style usage 2013-11-20 09:24:18 -07:00
daemon Add network events to the remote driver 2013-12-11 13:26:25 +00:00
docs maint: improve VIR_ERR_INVALID_CONN usage 2014-01-06 21:41:02 -07:00
examples event-test: Unregister close callback 2013-12-24 17:18:34 +01:00
gnulib maint: update to latest gnulib 2014-01-01 06:02:47 -07:00
include docs: improve event-related documentation 2013-12-19 09:45:50 -07:00
m4 aarch64: Disable -fstack-protector. 2014-01-01 14:21:21 +00:00
po Extracted common parts of domain_event.[ch] to object_event.[ch] 2013-12-10 13:12:35 +00:00
src event: don't let old-style events clobber per-domain events 2014-01-07 09:12:10 -07:00
tests event: don't let old-style events clobber per-domain events 2014-01-07 09:12:10 -07:00
tools virkeycode: Allow ANSI_A 2013-12-24 17:36:47 +01:00
.ctags maint: Make ctags work out of the box 2013-07-18 08:47:21 +02:00
.dir-locals.el build: avoid tabs that failed syntax-check 2012-09-06 09:43:46 -06:00
.gitignore examples: Resurrect domsuspend example 2013-12-24 17:17:35 +01:00
.gitmodules make .gnulib a submodule 2009-07-08 16:17:51 +02:00
.mailmap Autogenerate AUTHORS 2012-10-19 12:44:56 -04:00
AUTHORS.in Add John Ferlan to the committers list 2013-02-05 10:59:32 -05:00
autobuild.sh Remove python binding 2013-11-25 16:08:00 +00:00
autogen.sh autogen.sh: Correctly detect .git as a file 2013-08-29 13:19:45 +02:00
bootstrap maint: update to latest gnulib 2014-01-01 06:02:47 -07:00
bootstrap.conf Add helpers for getting env vars in a setuid environment 2013-10-21 14:03:52 +01:00
cfg.mk examples: Resurrect domsuspend example 2013-12-24 17:17:35 +01:00
ChangeLog-old maint: typo fixes 2013-10-22 16:49:32 +01:00
config-post.h build: fix build of virt-login-shell on systems with older gnutls 2013-10-22 09:41:50 -06:00
configure.ac examples: Resurrect domsuspend example 2013-12-24 17:17:35 +01:00
COPYING maint: follow recommended practice for using LGPL 2013-05-20 14:15:21 -06:00
COPYING.LESSER maint: follow recommended practice for using LGPL 2013-05-20 14:15:21 -06:00
HACKING maint: enforce comma style usage 2013-11-20 09:24:18 -07:00
libvirt.pc.in Add missing 'libvirt_lxc_api' variable in pkg-config file 2013-09-04 14:52:40 +01:00
libvirt.spec.in examples: Resurrect domsuspend example 2013-12-24 17:17:35 +01:00
Makefile.am examples: Resurrect domsuspend example 2013-12-24 17:17:35 +01:00
Makefile.nonreentrant maint: use LGPL correctly 2013-05-20 14:03:48 -06:00
mingw-libvirt.spec.in Remove python binding 2013-11-25 16:08:00 +00:00
README Correct typos in the documentation (Atsushi SAKAI) 2008-01-24 10:15:13 +00:00
README-hacking maint: relax git minimum version 2010-02-24 14:29:27 -05:00
run.in Remove python binding 2013-11-25 16:08:00 +00:00
TODO Update todo list file to point at bugzilla/website 2010-10-13 16:45:26 +01:00

         LibVirt : simple API for virtualization

  Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.

Daniel Veillard <veillard@redhat.com>