Marc Hartmayer 7e760f6157 virDomainObjListAddLocked: fix double free
If @vm has flagged as "to be removed" virDomainObjListFindByNameLocked
returns NULL (although the definition actually exists). Therefore, the
possibility exits that "virHashAddEntry" will raise the error
"Duplicate key" => virDomainObjListAddObjLocked fails =>
virDomainObjEndAPI(&vm) is called and this leads to a freeing of @def
since @def is already assigned to vm->def. But actually this leads to
a double free since the common usage pattern is that the caller of
virDomainObjListAdd(Locked) is responsible for freeing @def in case of
an error.

Let's fix this by setting vm->def to NULL in case of an error.

Backtrace:

   ➤  bt
   #0  virFree (ptrptr=0x7575757575757575)
   #1  0x000003ffb5b25b3e in virDomainResourceDefFree
   #2  0x000003ffb5b37c34 in virDomainDefFree
   #3  0x000003ff9123f734 in qemuDomainDefineXMLFlags
   #4  0x000003ff9123f7f4 in qemuDomainDefineXML
   #5  0x000003ffb5cd2c84 in virDomainDefineXML
   #6  0x000000011745aa82 in remoteDispatchDomainDefineXML
   ...

Reviewed-by: Bjoern Walk <bwalk@linux.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
2018-08-29 10:02:03 +02:00
..
2018-08-13 11:53:53 +02:00
2018-06-11 18:33:13 -04:00

       libvirt library code README
       ===========================

The directory provides the bulk of the libvirt codebase. Everything
except for the libvirtd daemon and client tools. The build uses a
large number of libtool convenience libraries - one for each child
directory, and then links them together for the final libvirt.so,
although some bits get linked directly to libvirtd daemon instead.

The files directly in this directory are supporting the public API
entry points & data structures.

There are two core shared modules to be aware of:

 * util/  - a collection of shared APIs that can be used by any
            code. This directory is always in the include path
            for all things built

 * conf/  - APIs for parsing / manipulating all the official XML
            files used by the public API. This directory is only
            in the include path for driver implementation modules

 * vmx/   - VMware VMX config handling (used by esx/ and vmware/)


Then there are the hypervisor implementations:

 * bhyve         - bhyve - The BSD Hypervisor
 * esx/          - VMware ESX and GSX support using vSphere API over SOAP
 * hyperv/       - Microsoft Hyper-V support using WinRM
 * lxc/          - Linux Native Containers
 * openvz/       - OpenVZ containers using cli tools
 * phyp/         - IBM Power Hypervisor using CLI tools over SSH
 * qemu/         - QEMU / KVM using qemu CLI/monitor
 * remote/       - Generic libvirt native RPC client
 * test/         - A "mock" driver for testing
 * uml/          - User Mode Linux
 * vbox/         - Virtual Box using native API
 * vmware/       - VMware Workstation and Player using the vmrun tool
 * xen/          - Xen using hypercalls, XenD SEXPR & XenStore
 * xenapi/       - Xen using libxenserver


Finally some secondary drivers that are shared for several HVs.
Currently these are used by LXC, OpenVZ, QEMU, UML and Xen drivers.
The ESX, Hyper-V, Power Hypervisor, Remote, Test & VirtualBox drivers all
implement the secondary drivers directly

 * cpu/          - CPU feature management
 * interface/    - Host network interface management
 * network/      - Virtual NAT networking
 * nwfilter/     - Network traffic filtering rules
 * node_device/  - Host device enumeration
 * secret/       - Secret management
 * security/     - Mandatory access control drivers
 * storage/      - Storage management drivers


Since both the hypervisor and secondary drivers can be built as
dlopen()able modules, it is *FORBIDDEN* to have build dependencies
between these directories. Drivers are only allowed to depend on
the public API, and the internal APIs in the util/ and conf/
directories