[libvirt PATCH v2 3/5] nodedev: add macro to handle command errors

[Jonathon Jongsma <jjongsma@xxxxxxxxxx>]

This macro will be utilized in the following patch. Since mdevctl
commands can fail with or without an error message, this macro makes it
easy to print a fallback error in the case that the error message is not
set.

Signed-off-by: Jonathon Jongsma <jjongsma@xxxxxxxxxx>
---
 src/node_device/node_device_driver.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/node_device/node_device_driver.c b/src/node_device/node_device_driver.c
index 43a8c1bf60..eb85cc0439 100644
--- a/src/node_device/node_device_driver.c
+++ b/src/node_device/node_device_driver.c
@@ -57,6 +57,9 @@ VIR_ENUM_IMPL(virMdevctlCommand,
 );
 
 
+#define MDEVCTL_ERROR(msg) (msg && msg[0] != '\0' ? msg : _("Unknown error"))
+
+
 virDrvOpenStatus
 nodeConnectOpen(virConnectPtr conn,
                 virConnectAuthPtr auth G_GNUC_UNUSED,
@@ -1387,7 +1390,7 @@ nodeDeviceUndefine(virNodeDevice *device,
         if (virMdevctlUndefine(def, &errmsg) < 0) {
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("Unable to undefine mediated device: %s"),
-                           errmsg && errmsg[0] ? errmsg : "Unknown Error");
+                           MDEVCTL_ERROR(errmsg));
             goto cleanup;
         }
         ret = 0;
@@ -1434,7 +1437,7 @@ nodeDeviceCreate(virNodeDevice *device,
         if (virMdevctlStart(def, &errmsg) < 0) {
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("Unable to create mediated device: %s"),
-                           errmsg && errmsg[0] ? errmsg : "Unknown Error");
+                           MDEVCTL_ERROR(errmsg));
             goto cleanup;
         }
         ret = 0;
-- 
2.31.1