Re: [libvirt] [PATCH 07/26] qemu: Allow qemuBuildControllerDevStr() to return NULL

We will soon need to be able to return a NULL pointer without the caller considering that an error: to make it possible, change the return type to int and use an out parameter for the string instead. Add some documentation for the function as well. --- src/qemu/qemu_command.c | 53 ++++++++++++++++++++++++++++++++++++------------- src/qemu/qemu_command.h | 9 +++++---- src/qemu/qemu_hotplug.c | 5 ++++- 3 files changed, 48 insertions(+), 19 deletions(-) diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index 015af10..a0403bf 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -2664,10 +2664,31 @@ qemuCheckSCSIControllerIOThreads(const virDomainDef *domainDef, } -char * +/** + * qemuBuildControllerDevStr: + * @domainDef: domain definition + * @def: controller definition + * @qemuCaps: QEMU binary capabilities + * @devstr: device string + * @nusbcontroller: number of USB controllers + * + * Turn @def into a description of the controller that QEMU will understand, + * to be used either on the command line or through the monitor. + * + * The description will be returned in @devstr and can be NULL, eg. when + * passing in one of the built-in controllers. The returned string must be + * freed by the caller. + * + * The number pointed to by @nusbcontroller will be increased by one every + * time the description for a USB controller has been generated successfully. + * + * Returns: 0 on success, <0 on failure + */ +int qemuBuildControllerDevStr(const virDomainDef *domainDef, virDomainControllerDefPtr def, virQEMUCapsPtr qemuCaps, + char **devstr, int *nusbcontroller) { virBuffer buf = VIR_BUFFER_INITIALIZER;

@@ -2676,11 +2697,11 @@ qemuBuildControllerDevStr(const virDomainDef *domainDef, if (!qemuCheckCCWS390AddressSupport(domainDef, def->info, qemuCaps, "controller")) - return NULL; + return -1; if (def->type == VIR_DOMAIN_CONTROLLER_TYPE_SCSI) { if ((qemuDomainSetSCSIControllerModel(domainDef, qemuCaps, &model)) < 0) - return NULL; + return -1; } if (!(def->type == VIR_DOMAIN_CONTROLLER_TYPE_SCSI && @@ -2688,22 +2709,22 @@ qemuBuildControllerDevStr(const virDomainDef *domainDef, if (def->queues) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", _("'queues' is only supported by virtio-scsi controller")); - return NULL; + return -1; } if (def->cmd_per_lun) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", _("'cmd_per_lun' is only supported by virtio-scsi controller")); - return NULL; + return -1; } if (def->max_sectors) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", _("'max_sectors' is only supported by virtio-scsi controller")); - return NULL; + return -1; } if (def->ioeventfd) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", _("'ioeventfd' is only supported by virtio-scsi controller")); - return NULL; + return -1; } } @@ -3114,11 +3135,12 @@ qemuBuildControllerDevStr(const virDomainDef *domainDef, if (virBufferCheckError(&buf) < 0) goto error; - return virBufferContentAndReset(&buf); + *devstr = virBufferContentAndReset(&buf); + return 0; error: virBufferFreeAndReset(&buf); - return NULL; + return -1; } @@ -3213,12 +3235,15 @@ qemuBuildControllerDevCommandLine(virCommandPtr cmd, continue; } - virCommandAddArg(cmd, "-device"); - if (!(devstr = qemuBuildControllerDevStr(def, cont, qemuCaps, - &usbcontroller))) + if (qemuBuildControllerDevStr(def, cont, qemuCaps, + &devstr, &usbcontroller) < 0) return -1; - virCommandAddArg(cmd, devstr); - VIR_FREE(devstr); + + if (devstr) { + virCommandAddArg(cmd, "-device"); + virCommandAddArg(cmd, devstr); + VIR_FREE(devstr); + } } } diff --git a/src/qemu/qemu_command.h b/src/qemu/qemu_command.h index 09cb00e..9a2ab29 100644 --- a/src/qemu/qemu_command.h +++ b/src/qemu/qemu_command.h @@ -118,10 +118,11 @@ char *qemuBuildDriveDevStr(const virDomainDef *def, virQEMUCapsPtr qemuCaps); /* Current, best practice */ -char *qemuBuildControllerDevStr(const virDomainDef *domainDef, - virDomainControllerDefPtr def, - virQEMUCapsPtr qemuCaps, - int *nusbcontroller); +int qemuBuildControllerDevStr(const virDomainDef *domainDef, + virDomainControllerDefPtr def, + virQEMUCapsPtr qemuCaps, + char **devstr, + int *nusbcontroller); int qemuBuildMemoryBackendStr(virJSONValuePtr *backendProps, const char **backendType, diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index 4a7d997..f910012 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -523,7 +523,10 @@ int qemuDomainAttachControllerDevice(virQEMUDriverPtr driver, if (qemuAssignDeviceControllerAlias(vm->def, priv->qemuCaps, controller) < 0) goto cleanup; - if (!(devstr = qemuBuildControllerDevStr(vm->def, controller, priv->qemuCaps, NULL))) + if (qemuBuildControllerDevStr(vm->def, controller, priv->qemuCaps, &devstr, NULL) < 0) + goto cleanup; + + if (!devstr) goto cleanup; if (VIR_REALLOC_N(vm->def->controllers, vm->def->ncontrollers+1) < 0)