[libvirt] [PATCH v3] qemu: Add callback struct for qemuBuildCommandLine

[Osier Yang]

On 17/05/13 18:12, Daniel P. Berrange wrote:
> On Thu, May 16, 2013 at 11:02:00PM +0800, Osier Yang wrote:
>> Since 0d70656afded, it starts to access the sysfs files to build
>> the qemu command line (by virSCSIDeviceGetSgName, which is to find
>> out the scsi generic device name by adpater:bus:target:unit), there
>> is no way to work around, qemu wants to see the scsi generic device
>> like "/dev/sg6" anyway.
>>
>> And there might be other places which need to access sysfs files
>> when building qemu command line in future.
>>
>> Instead of increasing the arguments of qemuBuildCommandLine, this
>> introduces a new callback for qemuBuildCommandLine, and thus tests
>> can register their own callbacks for sysfs test input files accessing.
>>
>> * src/qemu/qemu_command.h: (New callback struct
>>                              qemuBuildCommandLineCallbacks;
>>                              extern buildCommandLineCallbacks)
>> * src/qemu/qemu_command.c: (wire up the callback struct)
>> * src/qemu/qemu_driver.c: (Use the new syntax of qemuBuildCommandLine)
>> * src/qemu/qemu_hotplug.c: Likewise
>> * src/qemu/qemu_process.c: Likewise
>> * tests/qemuxml2argvtest.c: (Helper testSCSIDeviceGetSgName;
>>                               callback struct testCallbacks;
>>                               Use the callback struct)
>> * src/tests/qemuxmlnstest.c  Use the new syntax of qemuBuildCommandLine)
>> ---
>>   src/qemu/qemu_command.c  | 28 ++++++++++++++++++++--------
>>   src/qemu/qemu_command.h  | 16 ++++++++++++++--
>>   src/qemu/qemu_driver.c   |  3 ++-
>>   src/qemu/qemu_hotplug.c  |  6 ++++--
>>   src/qemu/qemu_process.c  |  3 ++-
>>   tests/qemuxml2argvtest.c | 21 ++++++++++++++++++++-
>>   tests/qemuxmlnstest.c    |  3 ++-
>>   7 files changed, 64 insertions(+), 16 deletions(-)
>>
>> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
>> index 5b95c07..e775479 100644
>> --- a/src/qemu/qemu_command.c
>> +++ b/src/qemu/qemu_command.c
>> @@ -4757,18 +4757,25 @@ qemuBuildUSBHostdevUsbDevStr(virDomainHostdevDefPtr dev)
>>   
>>   char *
>>   qemuBuildSCSIHostdevDrvStr(virDomainHostdevDefPtr dev,
>> -                           virQEMUCapsPtr qemuCaps ATTRIBUTE_UNUSED)
>> +                           virQEMUCapsPtr qemuCaps ATTRIBUTE_UNUSED,
>> +                           qemuBuildCommandLineCallbacksPtr callbacks)
>>   {
>>       virBuffer buf = VIR_BUFFER_INITIALIZER;
>>       char *sg = NULL;
>>   
>> -    if (!(sg = virSCSIDeviceGetSgName(dev->source.subsys.u.scsi.adapter,
>> -                                      dev->source.subsys.u.scsi.bus,
>> -                                      dev->source.subsys.u.scsi.target,
>> -                                      dev->source.subsys.u.scsi.unit))) {
>> -        goto error;
>> +    if (!callbacks) {
>> +        virReportError(VIR_ERR_INVALID_ARG, "%s",
>> +                       _("callbacks cannot be NULL"));
>> +        return NULL;
> I think I'd remove this check and....
>
>
>> diff --git a/src/qemu/qemu_command.h b/src/qemu/qemu_command.h
>> index 36dfa6b..23b6af3 100644
>> --- a/src/qemu/qemu_command.h
>> +++ b/src/qemu/qemu_command.h
>> @@ -61,7 +71,8 @@ virCommandPtr qemuBuildCommandLine(virConnectPtr conn,
>>                                      const char *migrateFrom,
>>                                      int migrateFd,
>>                                      virDomainSnapshotObjPtr current_snapshot,
>> -                                   enum virNetDevVPortProfileOp vmop)
>> +                                   enum virNetDevVPortProfileOp vmop,
>> +                                   qemuBuildCommandLineCallbacksPtr callbacks)
>>       ATTRIBUTE_NONNULL(1);
> ...add another ATTRIBUTE_NONNULL here and...

Do we need ATTRIBUT_NONULL for qemuBuildCommandLine too? the
callbacks could be NULL in case of it won't call qemuBuildSCSIHostdevDrvStr,
or something else in future.

If it should be NONNULL, I have to set up the callback from qemuxmlnstest.c
too, the callbacks is meaningless for it though.

>
>>   
>>   /* Generate string for arch-specific '-device' parameter */
>> @@ -142,7 +153,8 @@ char * qemuBuildUSBHostdevDevStr(virDomainHostdevDefPtr dev,
>>                                    virQEMUCapsPtr qemuCaps);
>>   
>>   char * qemuBuildSCSIHostdevDrvStr(virDomainHostdevDefPtr dev,
>> -                                  virQEMUCapsPtr qemuCaps);
>> +                                  virQEMUCapsPtr qemuCaps,
>> +                                  qemuBuildCommandLineCallbacksPtr callbacks);
> ...the same here.
>
Agreed.