nodedev: allow opening with nodedev:///system and nodedev:///session URIs

Allow the possibility of opening a connection to only the nodedev
driver, by defining nodedev:///system and nodedev:///session URIs
and registering a fake hypervisor driver that supports them.

The hypervisor drivers can now directly open a nodedev driver
connection at time of need, instead of having to pass around a
virConnectPtr through many functions. This will facilitate the later
change to support separate daemons for each driver.
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

src/node_device/node_device_driver.c

@@ -46,6 +46,79 @@
 
 virNodeDeviceDriverStatePtr driver;
 
+virDrvOpenStatus
+nodeConnectOpen(virConnectPtr conn,
+                virConnectAuthPtr auth ATTRIBUTE_UNUSED,
+                virConfPtr conf ATTRIBUTE_UNUSED,
+                unsigned int flags)
+{
+    virCheckFlags(VIR_CONNECT_RO, VIR_DRV_OPEN_ERROR);
+
+    /* Verify uri was specified */
+    if (conn->uri == NULL) {
+        /* Only hypervisor drivers are permitted to auto-open on NULL uri */
+        return VIR_DRV_OPEN_DECLINED;
+    } else {
+        if (STRNEQ_NULLABLE(conn->uri->scheme, "nodedev"))
+            return VIR_DRV_OPEN_DECLINED;
+
+        /* Leave for remote driver */
+        if (conn->uri->server != NULL)
+            return VIR_DRV_OPEN_DECLINED;
+
+        if (driver == NULL) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("nodedev state driver is not active"));
+            return VIR_DRV_OPEN_ERROR;
+        }
+
+        if (driver->privileged) {
+            if (STRNEQ(conn->uri->path, "/system")) {
+                virReportError(VIR_ERR_INTERNAL_ERROR,
+                               _("unexpected nodedev URI path '%s', try nodedev:///system"),
+                               conn->uri->path);
+                return VIR_DRV_OPEN_ERROR;
+            }
+        } else {
+            if (STRNEQ(conn->uri->path, "/session")) {
+                virReportError(VIR_ERR_INTERNAL_ERROR,
+                               _("unexpected nodedev URI path '%s', try nodedev:///session"),
+                               conn->uri->path);
+                return VIR_DRV_OPEN_ERROR;
+            }
+        }
+    }
+
+    if (virConnectOpenEnsureACL(conn) < 0)
+        return VIR_DRV_OPEN_ERROR;
+
+    return VIR_DRV_OPEN_SUCCESS;
+}
+
+int nodeConnectClose(virConnectPtr conn ATTRIBUTE_UNUSED)
+{
+    return 0;
+}
+
+
+int nodeConnectIsSecure(virConnectPtr conn ATTRIBUTE_UNUSED)
+{
+    /* Trivially secure, since always inside the daemon */
+    return 1;
+}
+
+
+int nodeConnectIsEncrypted(virConnectPtr conn ATTRIBUTE_UNUSED)
+{
+    /* Not encrypted, but remote driver takes care of that */
+    return 0;
+}
+
+
+int nodeConnectIsAlive(virConnectPtr conn ATTRIBUTE_UNUSED)
+{
+    return 1;
+}
 
 #if defined (__linux__) && ( defined (WITH_HAL) || defined(WITH_UDEV))
 /* NB: It was previously believed that changes in driver name were
@@ -569,7 +642,6 @@ nodeConnectNodeDeviceEventDeregisterAny(virConnectPtr conn,
     return ret;
 }
 
-
 int
 nodedevRegister(void)
 {

src/node_device/node_device_driver.h

@@ -51,6 +51,15 @@ extern virNodeDeviceDriverStatePtr driver;
 int
 nodedevRegister(void);
 
+virDrvOpenStatus nodeConnectOpen(virConnectPtr conn,
+                                 virConnectAuthPtr auth,
+                                 virConfPtr conf,
+                                 unsigned int flags);
+int nodeConnectClose(virConnectPtr conn);
+int nodeConnectIsSecure(virConnectPtr conn);
+int nodeConnectIsEncrypted(virConnectPtr conn);
+int nodeConnectIsAlive(virConnectPtr conn);
+
 int
 nodeNumOfDevices(virConnectPtr conn,
                  const char *cap,

src/node_device/node_device_hal.c

@@ -772,6 +772,22 @@ static virNodeDeviceDriver halNodeDeviceDriver = {
 };
 
 
+static virHypervisorDriver halHypervisorDriver = {
+    .name = "nodedev",
+    .connectOpen = nodeConnectOpen, /* 4.1.0 */
+    .connectClose = nodeConnectClose, /* 4.1.0 */
+    .connectIsEncrypted = nodeConnectIsEncrypted, /* 4.1.0 */
+    .connectIsSecure = nodeConnectIsSecure, /* 4.1.0 */
+    .connectIsAlive = nodeConnectIsAlive, /* 4.1.0 */
+};
+
+
+static virConnectDriver halConnectDriver = {
+    .hypervisorDriver = &halHypervisorDriver,
+    .nodeDeviceDriver = &halNodeDeviceDriver,
+};
+
+
 static virStateDriver halStateDriver = {
     .name = "HAL",
     .stateInitialize = nodeStateInitialize, /* 0.5.0 */
@@ -782,6 +798,8 @@ static virStateDriver halStateDriver = {
 int
 halNodeRegister(void)
 {
+    if (virRegisterConnectDriver(&halConnectDriver, false) < 0)
+        return -1;
     if (virSetSharedNodeDeviceDriver(&halNodeDeviceDriver) < 0)
         return -1;
     return virRegisterStateDriver(&halStateDriver);

src/node_device/node_device_udev.c

@@ -1945,6 +1945,23 @@ static virNodeDeviceDriver udevNodeDeviceDriver = {
     .nodeDeviceDestroy = nodeDeviceDestroy, /* 0.7.3 */
 };
 
+
+static virHypervisorDriver udevHypervisorDriver = {
+    .name = "nodedev",
+    .connectOpen = nodeConnectOpen, /* 4.1.0 */
+    .connectClose = nodeConnectClose, /* 4.1.0 */
+    .connectIsEncrypted = nodeConnectIsEncrypted, /* 4.1.0 */
+    .connectIsSecure = nodeConnectIsSecure, /* 4.1.0 */
+    .connectIsAlive = nodeConnectIsAlive, /* 4.1.0 */
+};
+
+
+static virConnectDriver udevConnectDriver = {
+    .hypervisorDriver = &udevHypervisorDriver,
+    .nodeDeviceDriver = &udevNodeDeviceDriver,
+};
+
+
 static virStateDriver udevStateDriver = {
     .name = "udev",
     .stateInitialize = nodeStateInitialize, /* 0.7.3 */
@@ -1958,6 +1975,8 @@ udevNodeRegister(void)
 {
     VIR_DEBUG("Registering udev node device backend");
 
+    if (virRegisterConnectDriver(&udevConnectDriver, false) < 0)
+        return -1;
     if (virSetSharedNodeDeviceDriver(&udevNodeDeviceDriver) < 0)
         return -1;