dfa0efbb77
The virObjectIsClass API has only ever checked object validity
based on if the @obj is not NULL and it was derived from some class.
While this has worked well in general, there is one additional
check that could be made prior to calling virClassIsDerivedFrom
which loops through the classes checking the magic number against
the klass expected magic number.
If by chance a non virObject is passed, rather than assuming the
void * @obj is a _virObject and thus offsetting to obj->klass,
obj->magic, and obj->parent, let's check that the void * @obj
has at least the "base part" of the magic number in the right
place and generate a more specific VIR_WARN message if not.
There are many consumers to virObjectIsClass, include the locking
primitives virObject{Lock|Unlock}, virObjectRWLock{Read|Write},
and virObjectRWUnlock. For those callers, the locking call will
not fail, but it also will not attempt a virMutex* call which
will "most likely" fail since the &obj->lock is used.
In order to avoid some possible future wrap on the 0xCAFExxxx
value, add a check during initialization that some new class
won't cause the wrap. Should be good for a few years at least!
It is still left up to the caller to handle the failed API calls
just as it would be if it passed a NULL opaque pointer anyobj.
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: