4b8245653d
Previously there was no way to differentiate between this function 1) encountering an error while reading the pci config, and 2) determining that the device in question is a conventional PCI device, and so has no Express Capabilities. The difference between these two conditions is important, because an unprivileged libvirtd will be unable to read all of the pci config (it can only read the first 64 bytes, and will get ENOENT when it tries to seek past that limit) even though the device is in fact a PCIe device. This patch changes virPCIDeviceFindCapabilityOffset() to put the determined offset into an argument of the function (rather than sending it back as the return value), and to return the standard "0 on success, -1 on failure". Failure is determined by checking the value of errno after each attemptd read of the config file (which can only work reliably if errno is reset to 0 before each read, and after virPCIDeviceFindCapabilityOffset() has finished examining it). (NB: if the config file is read successfully, but no Express Capabilities are found, then the function returns success, but the returned offset will be 0 (which is an impossible offset for Express Capabilities, and so easily recognizeable). An upcoming patch will take advantage of the change made here. Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@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
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: