From 1da246305bff2d60828a08024cb9db5873fef49a Mon Sep 17 00:00:00 2001

Message-Id: <1da246305bff2d60828a08024cb9db5873fef49a@dist-git>

From: Andrea Bolognani <abologna@redhat.com>

Date: Mon, 17 Jul 2017 12:09:04 +0200

Subject: [PATCH] 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.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>

Reviewed-by: Laine Stump <laine@laine.org>

(cherry picked from commit 0e943cec9e0ce10565fa4d94b06eae4e46a2925d)

Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1431193

Signed-off-by: Andrea Bolognani <abologna@redhat.com>

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

---

 src/qemu/qemu_command.c | 55 ++++++++++++++++++++++++++++++++++++-------------

 src/qemu/qemu_command.h |  9 ++++----

 src/qemu/qemu_hotplug.c |  5 ++++-

 3 files changed, 50 insertions(+), 19 deletions(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c

index 7ad3d16ea8..9e075e14d2 100644

--- a/src/qemu/qemu_command.c

+++ b/src/qemu/qemu_command.c

@@ -2702,23 +2702,46 @@ 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;

     int model = def->model;

     const char *modelName = NULL;

+    *devstr = NULL;

+

     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 &&

@@ -2726,22 +2749,22 @@ 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;

         }

     }

@@ -3156,11 +3179,12 @@ 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;

 }

@@ -3255,12 +3279,15 @@ 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 09cb00ee9b..9a2ab29e9a 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 316bc7d41e..476e2b81a3 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)

-- 

2.13.3