nodedev: add PostParse callback for nodedev parsing

This can be used similarly to other postparse callbacks in libvirt --
filling in additional information that can be determined by using the
information provided in the XML. In this case, we determine the address
of the parent device and cache it in the mdev caps so that we can use it
for generating a unique name and interacting with mdevctl.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

src/conf/node_device_conf.c

@@ -2185,6 +2185,13 @@ virNodeDeviceDefParse(const char *str,
 
     if (parserCallbacks) {
         int ret = 0;
+        /* fill in backend-specific aspects */
+        if (parserCallbacks->postParse) {
+            ret = parserCallbacks->postParse(def, opaque);
+            if (ret < 0)
+                return NULL;
+        }
+
         /* validate definition */
         if (parserCallbacks->validate) {
             ret = parserCallbacks->validate(def, opaque);

src/node_device/node_device_driver.c

@@ -718,11 +718,9 @@ nodeDeviceGetMdevctlCommand(virNodeDeviceDef *def,
                             char **outbuf,
                             char **errbuf)
 {
-    g_autofree char *parent_addr = NULL;
     g_autoptr(virCommand) cmd = NULL;
     const char *subcommand = virMdevctlCommandTypeToString(cmd_type);
     g_autofree char *inbuf = NULL;
-    virNodeDeviceObj *parent_obj = NULL;
 
     switch (cmd_type) {
     case MDEVCTL_CMD_CREATE:
@@ -747,12 +745,7 @@ nodeDeviceGetMdevctlCommand(virNodeDeviceDef *def,
     switch (cmd_type) {
     case MDEVCTL_CMD_CREATE:
     case MDEVCTL_CMD_DEFINE:
-        if ((parent_obj = nodeDeviceObjFindByName(def->parent))) {
-            parent_addr = nodeDeviceObjFormatAddress(parent_obj);
-            virNodeDeviceObjEndAPI(&parent_obj);
-        }
-
-        if (!parent_addr) {
+        if (!def->caps->data.mdev.parent_addr) {
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("unable to find parent device '%s'"), def->parent);
             return NULL;
@@ -764,7 +757,7 @@ nodeDeviceGetMdevctlCommand(virNodeDeviceDef *def,
             return NULL;
         }
 
-        virCommandAddArgPair(cmd, "--parent", parent_addr);
+        virCommandAddArgPair(cmd, "--parent", def->caps->data.mdev.parent_addr);
         virCommandAddArgPair(cmd, "--jsonfile", "/dev/stdin");
 
         virCommandSetInputBuffer(cmd, inbuf);
@@ -1764,9 +1757,30 @@ nodeDeviceDefCopyFromMdevctl(virNodeDeviceDef *dst,
 }
 
 
+int nodeDeviceDefPostParse(virNodeDeviceDef *def,
+                           G_GNUC_UNUSED void *opaque)
+{
+    virNodeDevCapsDef *caps = NULL;
+    for (caps = def->caps; caps != NULL; caps = caps->next) {
+        if (caps->data.type == VIR_NODE_DEV_CAP_MDEV) {
+            virNodeDeviceObj *obj = NULL;
+
+            if (def->parent)
+                obj = virNodeDeviceObjListFindByName(driver->devs, def->parent);
+
+            if (obj) {
+                caps->data.mdev.parent_addr = nodeDeviceObjFormatAddress(obj);
+                virNodeDeviceObjEndAPI(&obj);
+            }
+        }
+    }
+    return 0;
+}
+
+
 /* validate that parent exists */
 static int nodeDeviceDefValidateMdev(virNodeDeviceDef *def,
-                                     G_GNUC_UNUSED virNodeDevCapMdev *mdev,
+                                     virNodeDevCapMdev *mdev,
                                      G_GNUC_UNUSED void *opaque)
 {
     virNodeDeviceObj *obj = NULL;
@@ -1782,8 +1796,17 @@ static int nodeDeviceDefValidateMdev(virNodeDeviceDef *def,
                        def->parent);
         return -1;
     }
-
     virNodeDeviceObjEndAPI(&obj);
+
+    /* the post-parse callback should have found the address of the parent
+     * device and stored it in the mdev caps */
+    if (!mdev->parent_addr) {
+        virReportError(VIR_ERR_PARSE_FAILED,
+                       _("Unable to find address for parent device '%s'"),
+                       def->parent);
+        return -1;
+    }
+
     return 0;
 }
 

src/node_device/node_device_driver.h

@@ -172,5 +172,8 @@ int
 nodeDeviceCreate(virNodeDevice *dev,
                  unsigned int flags);
 
+int nodeDeviceDefPostParse(virNodeDeviceDef *def,
+                           void *opaque);
+
 int nodeDeviceDefValidate(virNodeDeviceDef *def,
                           void *opaque);

src/node_device/node_device_udev.c

@@ -2243,6 +2243,7 @@ nodeStateInitialize(bool privileged,
     driver->privateData = priv;
     driver->nodeDeviceEventState = virObjectEventStateNew();
 
+    driver->parserCallbacks.postParse = nodeDeviceDefPostParse;
     driver->parserCallbacks.validate = nodeDeviceDefValidate;
 
     if (udevPCITranslateInit(privileged) < 0)

tests/nodedevmdevctltest.c

@@ -13,6 +13,7 @@
 #define VIRT_TYPE "QEMU"
 
 static virNodeDeviceDefParserCallbacks parser_callbacks = {
+    .postParse = nodeDeviceDefPostParse,
     .validate = nodeDeviceDefValidate
 };