qemu: Abstract shmem socket path preparation

Put it into qemuDomainPrepareShmemChardev() so it can be used later.
Also don't fill in the path unless the server option is enabled.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

src/qemu/qemu_command.c

@@ -8560,10 +8560,7 @@ qemuBuildShmemBackendStr(virLogManagerPtr logManager,
 {
     char *devstr = NULL;
 
-    if (!shmem->server.chr.data.nix.path &&
-        virAsprintf(&shmem->server.chr.data.nix.path,
-                    "/var/lib/libvirt/shmem-%s-sock",
-                    shmem->name) < 0)
+    if (qemuDomainPrepareShmemChardev(shmem) < 0)
         return NULL;
 
     devstr = qemuBuildChrChardevStr(logManager, cmd, cfg, def,

src/qemu/qemu_domain.c

@@ -6056,6 +6056,19 @@ qemuDomainPrepareChannel(virDomainChrDefPtr channel,
 }
 
 
+int
+qemuDomainPrepareShmemChardev(virDomainShmemDefPtr shmem)
+{
+    if (!shmem->server.enabled ||
+        shmem->server.chr.data.nix.path)
+        return 0;
+
+    return virAsprintf(&shmem->server.chr.data.nix.path,
+                       "/var/lib/libvirt/shmem-%s-sock",
+                       shmem->name);
+}
+
+
 /**
  * qemuDomainVcpuHotplugIsInOrder:
  * @def: domain definition

src/qemu/qemu_domain.h

@@ -722,6 +722,9 @@ int qemuDomainPrepareChannel(virDomainChrDefPtr chr,
                              const char *domainChannelTargetDir)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
 
+int qemuDomainPrepareShmemChardev(virDomainShmemDefPtr shmem)
+    ATTRIBUTE_NONNULL(1);
+
 bool qemuDomainVcpuHotplugIsInOrder(virDomainDefPtr def)
     ATTRIBUTE_NONNULL(1);