d146105f1e
Our virCommand module allows us to set a pidfile for commands we want to spawn. The caller constructs the string of pidfile path and then uses virCommandSetPidFile() to tell the module to write the pidfile once the command is ran. This usually works, but has two flaws: 1) the child process does not hold the pidfile open & locked. Therefore, the caller (or anybody else) can't use our fancy virPidFileForceCleanupPath() function to kill the command afterwards. Also, for everybody else on the system it's needlessly harder to check if the pid from the pidfile is still alive or not. 2) if the caller ever makes a mistake and passes the same pidfile path for two different commands, the start of the second command will overwrite the pidfile even though the first command might still be running. NOTE that this temporarily renders some command spawning unusable, specifically those code patterns where both virCommandSetPidFile() is used together with instructing spawned command to acquire pidfile itself. Fortunately, there is only one occurrence of such pattern and it is in qemuProcessStartManagedPRDaemon(). This is fixed in next commit. Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@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 2.0 (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, however, we mandate to have the build directory different than the source directory. For example, to build in a manner that is suitable for installing as root, use:
$ mkdir build && cd build
$ ../configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
$ make
$ sudo make install
While to build & install as an unprivileged user
$ mkdir build && cd build
$ ../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: