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

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)