Re: [libvirt] [PATCH python 1/1] Fix type extracting from PyDict

On Wed, Feb 07, 2018 at 01:46:00PM +0300, Edgar Kaziakhmedov wrote: > Ping > > > On 01/31/2018 07:34 PM, Edgar Kaziakhmedov wrote: >> PyInt_Check returns value whether or not an input object is the integer >> type. The existing implementation of extracting leads to the wrong >> type interpretation in the following code: >> >> params = {libvirt.VIR_MIGRATE_PARAM_DISKS_PORT : 50123} >> ... >> dom.migrate3(%option1, params, %option3) >> >> where libvirt reports: >> >> libvirt.libvirtError: invalid argument: invalid type 'ullong' for >> parameter 'disks_port', expected 'int' >> >> So, this patch fixes that bug and allows casting to the VIR_TYPED_PARAM_INT >> type. >> >> Signed-off-by: Edgar Kaziakhmedov <edgar.kaziakhmedov(a)virtuozzo.com&gt; >> --- >> libvirt-utils.c | 5 +---- >> 1 file changed, 1 insertion(+), 4 deletions(-) >> >> diff --git a/libvirt-utils.c b/libvirt-utils.c >> index f7b4478..3a00e9f 100644 >> --- a/libvirt-utils.c >> +++ b/libvirt-utils.c >> @@ -434,10 +434,7 @@ virPyDictToTypedParamOne(virTypedParameterPtr *params, >> type = VIR_TYPED_PARAM_ULLONG; >> #if PY_MAJOR_VERSION < 3 >> } else if (PyInt_Check(value)) { >> - if (PyInt_AS_LONG(value) < 0) >> - type = VIR_TYPED_PARAM_LLONG; >> - else >> - type = VIR_TYPED_PARAM_ULLONG; >> + type = VIR_TYPED_PARAM_INT; >> #endif >> } else if (PyFloat_Check(value)) { >> type = VIR_TYPED_PARAM_DOUBLE; I very much doubt this is the right fix. This virPyDictToTypedParamOne method is used by several callers and many different parameters, and your change affects all of them. IOW, every typed parameter that is currently sent as a LLONG gets turned into an INT now.

This is good for the "disks_port" field but bad for the "bandwidth" field for example, so you've just moved where the brokeness is AFAICT. This method is simply broken by design IMHO. You cann't reliably identify which libvirt integer type is required by introspecting the python type. The Python glue code needs to explicitly say which type to use for each named parameter, based on the documented requirements in the libvirt header file. eg the python needs to take the same approach as done in the Perl binding here: https://libvirt.org/git/?p=libvirt-perl.git;a=blob;f=Virt.xs;h=f19880f800... Regards, Daniel