When debugging libvirt it is helpful to set probes around RPC
calls. We already have probes for libvirt's native RPC layer,
so it makes sense to add them for the DBus RPC layer too.
When converting to virObject, the probes on the 'Free' functions
were removed on the basis that there is a probe on virObjectFree
that suffices. This puts a burden on people writing probe scripts
to identify which object is being dispose. This adds back probes
in the 'Dispose' functions and updates the rpc monitor systemtap
example to use them
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This introduces a fairly basic reference counted virObject type
and an associated virClass type, that use atomic operations for
ref counting.
In a global initializer (recommended to be invoked using the
virOnceInit API), a virClass type must be allocated for each
object type. This requires a class name, a "dispose" callback
which will be invoked to free memory associated with the object's
fields, and the size in bytes of the object struct.
eg,
virClassPtr connclass = virClassNew("virConnect",
sizeof(virConnect),
virConnectDispose);
The struct for the object, must include 'virObject' as its
first member
eg
struct _virConnect {
virObject object;
virURIPtr uri;
};
The 'dispose' callback is only responsible for freeing
fields in the object, not the object itself. eg a suitable
impl for the above struct would be
void virConnectDispose(void *obj) {
virConnectPtr conn = obj;
virURIFree(conn->uri);
}
There is no need to reset fields to 'NULL' or '0' in the
dispose callback, since the entire object will be memset
to 0, and the klass pointer & magic integer fields will
be poisoned with 0xDEADBEEF before being free()d
When creating an instance of an object, one needs simply
pass the virClassPtr eg
virConnectPtr conn = virObjectNew(connclass);
if (!conn)
return NULL;
conn->uri = virURIParse("foo:///bar")
Object references can be manipulated with
virObjectRef(conn)
virObjectUnref(conn)
The latter returns a true value, if the object has been
freed (ie its ref count hit zero)
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The previous commit removed the only usage of ``all'' parameter in
virKeepAliveStopInternal, which was actually the only reason for having
virKeepAliveStopInternal. This effectively reverts most of commit
6446a9e20c.
When building as driver modules, it is not possible for the QEMU
driver module to reference the DTrace/SystemTAP probes linked into
the main libvirt.so. Thus we need to move the QEMU probes into a
separate file 'libvirt_qemu_probes.d'. Also rename the existing
file from 'probes.d' to 'libvirt_probes.d' while we're at it
* daemon/Makefile.am, src/internal.h: Include libvirt_probes.h
instead of probes.h
* src/Makefile.am: Add rules for libvirt_qemu_probes.d
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor_json.c,
src/qemu/qemu_monitor_text.c: Include libvirt_qemu_probes.h
* src/libvirt_probes.d: Rename from probes.d
* src/libvirt_qemu_probes.d: QEMU specific probes formerly
in probes.d
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
