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Michal Privoznik
8da362fe62
Okay, here is the deal. Currently, the way we build namespace is very fragile. It is done from pre-exec hook when starting a domain, after we mass closed all FDs and before we drop privileges and exec() QEMU. This fact poses some limitations onto the namespace build code, e.g. it has to make sure not to keep any FD opened (not even through a library call), because it would be leaked to QEMU. Also, it has to call only async signal safe functions. These requirements are hard to meet - in fact as of my commit v6.2.0-rc1~235 we are leaking a FD into QEMU by calling libdevmapper functions. To solve this issue and avoid similar problems in the future, we should change our paradigm. We already have functions which can populate domain's namespace with nodes from the daemon context. If we use them to populate the namespace and keep only the bare minimum in the pre-exec hook, we've mitigated the risk. Therefore, the old qemuDomainBuildNamespace() is renamed to qemuDomainUnshareNamespace() and new qemuDomainBuildNamespace() function is introduced. So far, the new function is basically a NOP and domain's namespace is still populated from the pre-exec hook - next patches will fix it. Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Ján Tomko <jtomko@redhat.com>
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==============================
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:
https://libvirt.org
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
============
Instructions on building and installing libvirt can be found on the website:
https://libvirt.org/compiling.html
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:
https://libvirt.org/contact.html