40bc98ddaf
Rework the logic in qemuDomainSnapshotLoad() to set vm->current_snapshot only once at the end of the loop, rather than repeatedly querying it during the loop, to make it easier for the next patch to use accessor functions rather than direct manipulation of vm->current_snapshot. When encountering multiple snapshots claiming to be current (based on the presence of an <active>1</active> element in the XML, which libvirt only outputs for internal use and not for any public API), this changes behavior from warning only once and running with no current snapshot, to instead warning on each duplicate and selecting the last one encountered (which is arbitrary based on readdir() ordering, but actually stands a fair chance of being the most-recently created snapshot whether by timestamp or by the propensity of humans to name things in ascending order). Note that the code in question is only run by libvirtd when it first starts, reading state from disk from the previous run into memory for this run. Since the data resides somewhere that only libvirt should be touching (typically /var/lib/libvirt/qemu/snapshot/*), it should be clean. So in the common case, the code touched here is unreachable. But if someone is actually messing with files behind libvirt's back, they deserve the change in behavior. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: John Ferlan <jferlan@redhat.com>
Libvirt API for virtualization
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.
For some of these hypervisors, it provides a stateful management daemon which runs on the virtualization host allowing access to the API both by non-privileged local users and remote users.
Layered packages provide bindings of the libvirt C API into other languages including Python, Perl, PHP, Go, Java, OCaml, as well as mappings into object systems such as GObject, CIM and SNMP.
Further information about the libvirt project can be found on the website:
License
The libvirt C API is distributed under the terms of GNU Lesser General
Public License, version 2.1 (or later). Some parts of the code that are
not part of the C library may have the more restrictive GNU General
Public License, version 2.1 (or later). See the files COPYING.LESSER
and COPYING for full license terms & conditions.
Installation
Libvirt uses the GNU Autotools build system, so in general can be built and installed with the usual commands. For example, to build in a manner that is suitable for installing as root, use:
$ ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
$ make
$ sudo make install
While to build & install as an unprivileged user
$ ./configure --prefix=$HOME/usr
$ make
$ make install
The libvirt code relies on a large number of 3rd party libraries. These will
be detected during execution of the configure script and a summary printed
which lists any missing (optional) dependencies.
Contributing
The libvirt project welcomes contributions in many ways. For most components the best way to contribute is to send patches to the primary development mailing list. Further guidance on this can be found on the website:
https://libvirt.org/contribute.html
Contact
The libvirt project has two primary mailing lists:
- libvirt-users@redhat.com (for user discussions)
- libvir-list@redhat.com (for development only)
Further details on contacting the project are available on the website: