[gnome-continuous-yocto/gnomeostree-3.28-rocko: 2676/8267] scripts/runqemu: provide better error message on runqemu ifup fail

[Emmanuele Bassi <ebassi src gnome org>]

commit 1d1f94b944161a0db78985b8f58da0828d68ce71
Author: Stephano Cetola <stephano cetola linux intel com>
Date:   Thu Sep 22 18:25:08 2016 -0700

    scripts/runqemu: provide better error message on runqemu ifup fail
    
    If runqemu-ifup fails hen running testimage, a rather cryptic error
    regarding "no tty present" is displayed. If this step fails, we
    should at least point the user at runqemu-gen-tapdevs. A quick search
    of this term in the manual will lead them to "Enabling Runtime Tests
    on QEMU" which should give them all the info they need.
    
    (From OE-Core rev: 3b6494fad2b8b65e0d52cda0cdf500e93c72823a)
    
    Signed-off-by: Stephano Cetola <stephano cetola linux intel com>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 scripts/runqemu |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/scripts/runqemu b/scripts/runqemu
index 5095e67..45bcad7 100755
--- a/scripts/runqemu
+++ b/scripts/runqemu
@@ -786,6 +786,9 @@ class BaseConfig(object):
             self.cleantap = True
             logger.info('Created tap: %s' % tap)
 
+        if not tap:
+            logger.error("Failed to setup tap device. Run runqemu-gen-tapdevs to manually create.")
+            return 1
         self.tap = tap
         n0 = tap[3:]
         n1 = int(n0) * 2 + 1