Libvirt provides a portable, long term stable C API for managing the virtualization technologies provided by many operating systems. It includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER Hypervisor.
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Michal Privoznik 2af51483cc processSerialChangedEvent: Close agent monitor early
https://bugzilla.redhat.com/show_bug.cgi?id=890648

So, imagine you've issued an API that involves guest agent. For
instance, you want to query guest's IP addresses. So the API acquires
QUERY_JOB, locks the guest agent and issues the agent command.
However, for some reason, guest agent replies to initial ping
correctly, but then crashes tragically while executing real command
(in this case guest-network-get-interfaces). Since initial ping went
well, libvirt thinks guest agent is accessible and awaits reply to the
real command. But it will never come. What will is a monitor event.
Our handler (processSerialChangedEvent) will try to acquire
MODIFY_JOB, which will fail obviously because the other thread that's
executing the API already holds a job. So the event handler exits
early, and the QUERY_JOB is never released nor ended.

The way how to solve this is to put flag somewhere in the monitor
internals. The flag is called @running and agent commands are issued
iff the flag is set. The flag itself is set when we connect to the
agent socket. And unset whenever we see DISCONNECT event from the
agent. Moreover, we must wake up all the threads waiting for the
agent. This is done by signalizing the condition they're waiting on.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2015-05-07 11:31:17 +02:00
.gnulib@106a3866d0 maint: update to latest gnulib 2015-03-26 09:41:55 -06:00
build-aux bracket-spacing: Add syntax-check for unnecessary curly brackets 2014-11-14 17:13:36 +01:00
daemon libxl: add logrotate config file 2015-05-05 09:08:11 -06:00
docs docs: fix a small xml error in docs 2015-05-05 09:30:44 -04:00
examples Apparmor: allow reading block-rbd.so 2015-04-24 10:47:42 +02:00
gnulib maint: fix date in local gnulib patch 2015-01-05 16:44:10 +00:00
include Implement virDomainAddIOThread and virDomainDelIOThread 2015-04-27 12:36:36 -04:00
m4 rpm-build: use pkg-config to detect wireshark presence 2015-03-16 22:58:54 +01:00
po Release of libvirt-1.2.15 2015-05-04 11:43:04 +08:00
src processSerialChangedEvent: Close agent monitor early 2015-05-07 11:31:17 +02:00
tests qemu: Implement GIC 2015-05-05 09:45:52 +02:00
tools virsh: Don't check migrate parameters 2015-05-04 15:06:33 +02:00
.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 main: add new generated files to .gitignore 2015-04-30 18:39:34 +02:00
.gitmodules make .gnulib a submodule 2009-07-08 16:17:51 +02:00
.mailmap maint: update .mailmap for recent contributions 2015-03-20 06:17:55 -06:00
AUTHORS.in AUTHORS: Add my email address to AUTHORS.in 2015-04-10 18:26:43 +03:00
autobuild.sh Disable libvirtd by default when building on Win32 2014-04-29 11:30:32 +01:00
autogen.sh maint: improve usage of autogen's --no-git 2015-02-06 11:35:29 -07:00
bootstrap maint: update to latest gnulib 2015-03-26 09:41:55 -06:00
bootstrap.conf Revert "bootstrap.conf: add check for flex" 2015-01-12 10:14:30 -07:00
cfg.mk cfg: Disallow usage of 'index' as variable name 2015-04-14 11:18:28 -04:00
ChangeLog-old Fix typos in src/* 2014-04-21 16:49:08 -06:00
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 Bump version to 1.2.16 for new dev cycle 2015-05-04 13:04:39 +02:00
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 tests: Add VIR_TEST_REGENERATE_OUTPUT 2015-04-23 17:08:48 -04:00
libvirt-lxc.pc.in Add pkg-config files for libvirt-qemu & libvirt-lxc 2014-06-23 16:17:27 +01:00
libvirt-qemu.pc.in Add pkg-config files for libvirt-qemu & libvirt-lxc 2014-06-23 16:17:27 +01:00
libvirt.pc.in Add pkg-config files for libvirt-qemu & libvirt-lxc 2014-06-23 16:17:27 +01:00
libvirt.spec.in libxl: add logrotate config file 2015-05-05 09:08:11 -06:00
Makefile.am examples: Introduce domtop 2014-07-18 16:39:54 +02:00
Makefile.nonreentrant maint: use LGPL correctly 2013-05-20 14:03:48 -06:00
mingw-libvirt.spec.in Move virConnect related APIs out of libvirt.h.in 2014-10-24 17:23:51 +01:00
README Correct typos in the documentation (Atsushi SAKAI) 2008-01-24 10:15:13 +00:00
README-hacking docs: update README-hacking 2014-05-06 16:20:24 -06:00
run.in Add PKG_CONFIG_PATH to run.in script. 2014-06-26 14:32:35 +01:00
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>