[libvirt] [PATCH v3 1/7] Allow for ff callbacks to be called by custom event implementations

From: Wojtek Porczyk <woju(a)invisiblethingslab.com&gt; The documentation says: And they did deadlock. In removeTimeout too. Now we supply a custom function to pick it from the opaque blob and fire. Signed-off-by: Wojtek Porczyk <woju(a)invisiblethingslab.com&gt; Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; --- libvirt-override.c | 68 ++++++++++++++++++++++++++++++----------------------- libvirt-override.py | 23 ++++++++++++++++++ sanitytest.py | 3 ++- 3 files changed, 63 insertions(+), 31 deletions(-) diff --git a/libvirt-override.c b/libvirt-override.c index 93c7ef0..a762941 100644 --- a/libvirt-override.c +++ b/libvirt-override.c @@ -5223,6 +5223,9 @@ libvirt_virEventAddHandleFunc(int fd, VIR_PY_TUPLE_SET_GOTO(pyobj_args, 3, cb_args, cleanup); + /* If changing contents of the opaque object, please also change + * virEventInvokeFreeCallback() in libvirt-override.py + */ VIR_PY_TUPLE_SET_GOTO(cb_args, 0, libvirt_virEventHandleCallbackWrap(cb), cleanup); VIR_PY_TUPLE_SET_GOTO(cb_args, 1, libvirt_virVoidPtrWrap(opaque), cleanup); VIR_PY_TUPLE_SET_GOTO(cb_args, 2, libvirt_virFreeCallbackWrap(ff), cleanup); @@ -5279,10 +5282,7 @@ libvirt_virEventRemoveHandleFunc(int watch) { PyObject *result = NULL; PyObject *pyobj_args; - PyObject *opaque; - PyObject *ff; int retval = -1; - virFreeCallback cff; LIBVIRT_ENSURE_THREAD_STATE; @@ -5292,20 +5292,11 @@ libvirt_virEventRemoveHandleFunc(int watch) VIR_PY_TUPLE_SET_GOTO(pyobj_args, 0, libvirt_intWrap(watch), cleanup); result = PyEval_CallObject(removeHandleObj, pyobj_args); - if (!result) { + if (result) { + retval = 0; + } else { PyErr_Print(); PyErr_Clear(); - } else if (!PyTuple_Check(result) || PyTuple_Size(result) != 3) { - DEBUG("%s: %s must return opaque obj registered with %s" - "to avoid leaking libvirt memory\n", - __FUNCTION__, NAME(removeHandle), NAME(addHandle)); - } else { - opaque = PyTuple_GetItem(result, 1); - ff = PyTuple_GetItem(result, 2); - cff = PyvirFreeCallback_Get(ff); - if (cff) - (*cff)(PyvirVoidPtr_Get(opaque)); - retval = 0; } cleanup: @@ -5350,6 +5341,9 @@ libvirt_virEventAddTimeoutFunc(int timeout, VIR_PY_TUPLE_SET_GOTO(pyobj_args, 2, cb_args, cleanup); + /* If changing contents of the opaque object, please also change + * virEventInvokeFreeCallback() in libvirt-override.py + */ VIR_PY_TUPLE_SET_GOTO(cb_args, 0, libvirt_virEventTimeoutCallbackWrap(cb), cleanup); VIR_PY_TUPLE_SET_GOTO(cb_args, 1, libvirt_virVoidPtrWrap(opaque), cleanup); VIR_PY_TUPLE_SET_GOTO(cb_args, 2, libvirt_virFreeCallbackWrap(ff), cleanup); @@ -5403,10 +5397,7 @@ libvirt_virEventRemoveTimeoutFunc(int timer) { PyObject *result = NULL; PyObject *pyobj_args; - PyObject *opaque; - PyObject *ff; int retval = -1; - virFreeCallback cff; LIBVIRT_ENSURE_THREAD_STATE; @@ -5416,20 +5407,11 @@ libvirt_virEventRemoveTimeoutFunc(int timer) VIR_PY_TUPLE_SET_GOTO(pyobj_args, 0, libvirt_intWrap(timer), cleanup); result = PyEval_CallObject(removeTimeoutObj, pyobj_args); - if (!result) { + if (result) { + retval = 0; + } else { PyErr_Print(); PyErr_Clear(); - } else if (!PyTuple_Check(result) || PyTuple_Size(result) != 3) { - DEBUG("%s: %s must return opaque obj registered with %s" - "to avoid leaking libvirt memory\n", - __FUNCTION__, NAME(removeTimeout), NAME(addTimeout)); - } else { - opaque = PyTuple_GetItem(result, 1); - ff = PyTuple_GetItem(result, 2); - cff = PyvirFreeCallback_Get(ff); - if (cff) - (*cff)(PyvirVoidPtr_Get(opaque)); - retval = 0; } cleanup: @@ -5558,6 +5540,31 @@ libvirt_virEventInvokeTimeoutCallback(PyObject *self ATTRIBUTE_UNUSED, return VIR_PY_INT_SUCCESS; } +static PyObject * +libvirt_virEventInvokeFreeCallback(PyObject *self ATTRIBUTE_UNUSED, + PyObject *args) +{ + PyObject *py_f; + PyObject *py_opaque; + virFreeCallback cb; + void *opaque; + + if (!PyArg_ParseTuple(args, (char *) "OO:virEventInvokeFreeCallback", + &py_f, &py_opaque)) + return NULL; + + cb = (virFreeCallback) PyvirEventHandleCallback_Get(py_f); + opaque = (void *) PyvirVoidPtr_Get(py_opaque); + + if (cb) { + LIBVIRT_BEGIN_ALLOW_THREADS; + cb(opaque); + LIBVIRT_END_ALLOW_THREADS; + } + + return VIR_PY_INT_SUCCESS; +} + static void libvirt_virEventHandleCallback(int watch, int fd, @@ -9572,6 +9579,7 @@ static PyMethodDef libvirtMethods[] = { {(char *) "virEventAddTimeout", libvirt_virEventAddTimeout, METH_VARARGS, NULL}, {(char *) "virEventInvokeHandleCallback", libvirt_virEventInvokeHandleCallback, METH_VARARGS, NULL}, {(char *) "virEventInvokeTimeoutCallback", libvirt_virEventInvokeTimeoutCallback, METH_VARARGS, NULL}, + {(char *) "virEventInvokeFreeCallback", libvirt_virEventInvokeFreeCallback, METH_VARARGS, NULL}, {(char *) "virNodeListDevices", libvirt_virNodeListDevices, METH_VARARGS, NULL}, #if LIBVIR_CHECK_VERSION(0, 10, 2) {(char *) "virConnectListAllNodeDevices", libvirt_virConnectListAllNodeDevices, METH_VARARGS, NULL}, diff --git a/libvirt-override.py b/libvirt-override.py index 63f8ecb..b0b24ef 100644 --- a/libvirt-override.py +++ b/libvirt-override.py @@ -211,3 +211,26 @@ def virEventAddTimeout(timeout, cb, opaque): ret = libvirtmod.virEventAddTimeout(timeout, cbData) if ret == -1: raise libvirtError ('virEventAddTimeout() failed') return ret + + +# +# a caller for the ff callbacks for custom event loop implementations +# + +def virEventInvokeFreeCallback(opaque): + """ + Execute callback which frees the opaque buffer + + @opaque: the opaque object passed to addHandle or addTimeout + + WARNING: This function should not be called from any call by libvirt's + core. It will most probably cause deadlock in C-level libvirt code. + Instead it should be scheduled and called from implementation's stack. + + See https://libvirt.org/html/libvirt-libvirt-event.html#virEventAddHandleFunc + for more information. + + This function is not dependent on any event loop implementation. + """ + + libvirtmod.virEventInvokeFreeCallback(opaque[2], opaque[1]) diff --git a/sanitytest.py b/sanitytest.py index a140ba2..7183baa 100644 --- a/sanitytest.py +++ b/sanitytest.py @@ -349,7 +349,8 @@ for klass in gotfunctions: continue for func in sorted(gotfunctions[klass]): # These are pure python methods with no C APi - if func in ["connect", "getConnect", "domain", "getDomain"]: + if func in ["connect", "getConnect", "domain", "getDomain", + "virEventInvokeFreeCallback"]: continue key = "%s.%s" % (klass, func) -- 2.9.3