qemu: support NBD with Unix sockets

This reuses the XML format that was introduced for Gluster.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>

docs/formatdomain.html.in

@@ -1713,9 +1713,11 @@
             <td> only one </td>
           </tr>
         </table>
-        In case of gluster, valid values for transport attribute are tcp, rdma
-        or unix. If nothing is specified, tcp is assumed. If transport is unix,
-        socket attribute specifies path to unix socket.
+        gluster supports "tcp", "rdma", "unix" as valid values for the
+        transport attribute.  nbd supports "tcp" and "unix".  Others only
+        support "tcp".  If nothing is specified, "tcp" is assumed. If the
+        transport is "unix", the socket attribute specifies the path to an
+        AF_UNIX socket.
       </dd>
       <dt><code>address</code></dt>
       <dd>If present, the <code>address</code> element ties the disk

src/qemu/qemu_command.c

@@ -2384,26 +2384,35 @@ qemuParseNBDString(virDomainDiskDefPtr disk)
         goto no_memory;
 
     host = disk->src + strlen("nbd:");
-    port = strchr(host, ':');
-    if (!port) {
-        virReportError(VIR_ERR_INTERNAL_ERROR,
-                       _("cannot parse nbd filename '%s'"), disk->src);
-        goto error;
+    if (STRPREFIX(host, "unix:/")) {
+        src = strchr(host + strlen("unix:"), ':');
+        if (src)
+            *src++ = '\0';
+
+        h->transport = VIR_DOMAIN_DISK_PROTO_TRANS_UNIX;
+        h->socket = strdup(host + strlen("unix:"));
+    } else {
+        port = strchr(host, ':');
+        if (!port) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("cannot parse nbd filename '%s'"), disk->src);
+            goto error;
+        }
+
+        *port++ = '\0';
+        h->name = strdup(host);
+        if (!h->name)
+            goto no_memory;
+
+        src = strchr(port, ':');
+        if (src)
+            *src++ = '\0';
+
+        h->port = strdup(port);
+        if (!h->port)
+            goto no_memory;
     }
 
-    *port++ = '\0';
-    h->name = strdup(host);
-    if (!h->name)
-        goto no_memory;
-
-    src = strchr(port, ':');
-    if (src)
-        *src++ = '\0';
-
-    h->port = strdup(port);
-    if (!h->port)
-        goto no_memory;
-
     if (src && STRPREFIX(src, "exportname=")) {
         src = strdup(strchr(src, '=') + 1);
         if (!src)
@@ -2510,6 +2519,14 @@ qemuBuildNBDString(virDomainDiskDefPtr disk, virBufferPtr opt)
                         disk->hosts->port ? disk->hosts->port :
                         QEMU_DEFAULT_NBD_PORT);
         break;
+    case VIR_DOMAIN_DISK_PROTO_TRANS_UNIX:
+        if (!disk->hosts->socket) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("socket attribute required for unix transport"));
+            return -1;
+        }
+        virBufferEscape(opt, ',', ",", "unix:%s", disk->hosts->socket);
+        break;
     default:
         transp = virDomainDiskProtocolTransportTypeToString(disk->hosts->transport);
         virReportError(VIR_ERR_INTERNAL_ERROR,

tests/qemuargv2xmltest.c

@@ -186,6 +186,7 @@ mymain(void)
     DO_TEST("disk-drive-cache-unsafe");
     DO_TEST("disk-drive-network-nbd");
     DO_TEST("disk-drive-network-nbd-export");
+    DO_TEST("disk-drive-network-nbd-unix");
     DO_TEST("disk-drive-network-gluster");
     DO_TEST("disk-drive-network-rbd");
     DO_TEST("disk-drive-network-rbd-ipv6");

tests/qemuxml2argvdata/qemuxml2argv-disk-drive-network-nbd-unix.args

@@ -0,0 +1,5 @@
+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M \
+pc -m 214 -smp 1 -nographic -monitor unix:/tmp/test-monitor,server,nowait \
+-no-acpi -boot c -usb -drive file=/dev/HostVG/QEMUGuest1,if=ide,bus=0,unit=0 \
+-drive file=nbd:unix:/var/run/nbdsock:exportname=bar,if=virtio,format=raw \
+-net none -serial none -parallel none

tests/qemuxml2argvdata/qemuxml2argv-disk-drive-network-nbd-unix.xml

@@ -0,0 +1,33 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <disk type='block' device='disk'>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <disk type='network' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source protocol='nbd' name='bar'>
+        <host transport='unix' socket='/var/run/nbdsock'/>
+      </source>
+      <target dev='vda' bus='virtio'/>
+    </disk>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -495,6 +495,8 @@ mymain(void)
             QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_FORMAT);
     DO_TEST("disk-drive-network-nbd-export",
             QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_FORMAT);
+    DO_TEST("disk-drive-network-nbd-unix",
+            QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_FORMAT);
     DO_TEST("disk-drive-network-gluster",
             QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_FORMAT);
     DO_TEST("disk-drive-network-rbd",

tests/qemuxml2xmltest.c

@@ -171,6 +171,7 @@ mymain(void)
     DO_TEST("disk-drive-cache-v1-none");
     DO_TEST("disk-drive-network-nbd");
     DO_TEST("disk-drive-network-nbd-export");
+    DO_TEST("disk-drive-network-nbd-unix");
     DO_TEST("disk-scsi-device");
     DO_TEST("disk-scsi-vscsi");
     DO_TEST("disk-scsi-virtio-scsi");