b647d2195d
Wire up support for VIR_DOMAIN_SNAPSHOT_LIST_TOPOLOGICAL in the domain-agnostic support code. Clients of snapshot_conf using virDomainSnapshotForEachDescendant() are using a depth-first visit but with postfix visits of a given node. Changing this to a prefix visit of the given node instantly turns this into a topologically-ordered visit. (A prefix breadth-first visit would also be topologically sorted, but that requires a queue while our recursion naturally has a stack). With that change, we now always have a topological sort for virDomainSnapshotListAllChildren() regardless of the new public API flag. Then with one more tweak, we can also get a topological rather than a faster random hash visit for virDomainListAllSnapshots(), by doing a descendent walk from our internal metaroot (there, we let the public API flag control behavior, because a topological sort DOES require more stack and slightly more time). Note that virDomainSnapshotForEach() still uses a random hash visit; we could change that signature to take a tri-state for random, prefix, or postfix visit if we ever had clients that cared about the distinctions, but for now, none of the drivers seem to care. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Ján Tomko <jtomko@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@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: