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.
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Michal Privoznik 46b03819ae qemu_namespace: Fix a corner case in qemuDomainGetPreservedMounts()
When setting up namespace for QEMU we look at mount points under
/dev (like /dev/pts, /dev/mqueue/, etc.) because we want to
preserve those (which is done by moving them to a temp location,
unshare(), and then moving them back). We have a convenience
helper - qemuDomainGetPreservedMounts() - that processes the
mount table and (optionally) moves the other filesystems too.
This helper is also used when attempting to create a path in NS,
because the path, while starting with "/dev/" prefix, may
actually lead to one of those filesystems that we preserved.

And here comes the corner case: while we require the parent mount
table to be in shared mode (equivalent of `mount --make-rshared /'),
these mount events propagate iff the target path exist inside the
slave mount table (= QEMU's private namespace). And since we
create only a subset of /dev nodes, well, that assumption is not
always the case.

For instance, assume that a domain is already running, no
hugepages were configured for it nor any hugetlbfs is mounted.
Now, when a hugetlbfs is mounted into '/dev/hugepages', this is
propagated into the QEMU's namespace, but since the target dir
does not exist in the private /dev, the FS is not mounted in the
namespace.

Fortunately, this difference between namespaces is visible when
comparing /proc/mounts and /proc/$PID/mounts (where PID is the
QEMU's PID). Therefore, if possible we should look at the latter.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
2022-09-23 16:32:51 +02:00
.ctags.d maint: Add support for .ctags.d 2019-05-31 17:54:28 +02:00
.github/workflows Switch to new GitHub repo-lockdown configuration 2021-10-20 14:27:20 +01:00
.gitlab/issue_templates gitlab: issue_template: Remove labelling commands 2022-06-01 12:27:10 +02:00
build-aux syntax-check: Add check prohibiting remote reference to local file 2022-06-01 12:27:10 +02:00
ci ci: refresh with latest lcitool manifest 2022-09-14 10:54:15 -04:00
docs docs: compiling: Add notes on starting compiled libvirt daemons 2022-09-13 13:36:49 +02:00
examples Introduce VIR_DOMAIN_RUNNING_POSTCOPY_FAILED 2022-06-07 17:40:20 +02:00
include admin: Introduce virAdmConnectSetDaemonTimeout 2022-07-07 14:35:30 +02:00
po Translated using Weblate (Swedish) 2022-09-20 14:46:19 +02:00
scripts scripts: Add $DESTDIR support to meson-install-web.py 2022-08-11 14:01:55 +02:00
src qemu_namespace: Fix a corner case in qemuDomainGetPreservedMounts() 2022-09-23 16:32:51 +02:00
tests tests: add better QEMU capabilities example 2022-09-21 12:02:40 +01:00
tools Remove support for building the sheepdog storage driver backend 2022-09-01 13:11:09 +02:00
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.gitmodules gnulib: delete all gnulib integration 2020-02-07 15:03:54 +00:00
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AUTHORS.rst.in AUTHORS: change my (Nikolay Shirokovskiy) email 2022-04-06 11:00:53 +03:00
config.h configure: bump min required CLang to 6.0 / XCode 10.0 2022-01-17 10:44:29 +00:00
configmake.h.in meson: generate configmake.h 2020-08-03 09:26:48 +02:00
CONTRIBUTING.rst meson: adjust our documentation to mention meson instead of autoconf 2020-08-03 09:27:09 +02:00
COPYING
COPYING.LESSER
gitdm.config gitdm: add 'ibm' file 2019-10-18 17:32:52 +02:00
libvirt-admin.pc.in
libvirt-lxc.pc.in
libvirt-qemu.pc.in
libvirt.pc.in
libvirt.spec.in meson: Require libssh-0.8.1 or newer 2022-09-20 09:34:52 +02:00
meson_options.txt Remove support for building the sheepdog storage driver backend 2022-09-01 13:11:09 +02:00
meson.build meson: Require libssh-0.8.1 or newer 2022-09-20 09:34:52 +02:00
NEWS.rst NEWS: Mention that non-shared storage migration was broken in libvirt-8.7 2022-09-09 16:10:47 +02:00
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run.in run: gracefully handle SIGHUP, SIGQUIT, SIGTERM 2022-03-10 08:06:12 +00:00

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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:

Further details on contacting the project are available on the website:

https://libvirt.org/contact.html