5c52aed174
The packet with passed FD has the following format:
--------------------------
| len | header | payload |
--------------------------
where "payload" has an additional count of FDs before the actual data:
------------------
| nfds | payload |
------------------
When the packet is received we parse the "header", which as a side
effect updates msg->bufferOffset to point to the beginning of "payload".
If the message call contains FDs, we need to also parse the count of
FDs, which also updates the msg->bufferOffset.
The issue here is that when we attempt to read the FDs data from the
socket and we receive EAGAIN we finish the reading and call poll()
to wait for the data the we need. When the data arrives we already have
the packet in our buffer so we read the "header" again but this time
we don't read the count of FDs because we already have it stored.
That means that the msg->bufferOffset is not updated to point to the
actual beginning of the payload data, but it points to the count of
FDs. After all FDs are processed we dispatch the message to process
it and decode the payload. Since the msg->bufferOffset points to wrong
data, we decode the wrong payload and the API call fails with
error messages:
Domain not found: no domain with matching uuid '67656e65-7269-6300-0c87-5003ca6941f2' ()
Broken by commit 133c511b527 which fixed a FD and memory leak.
Signed-off-by: Pavel Hrdina <phrdina@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: