pkg/59975: xenstore-read: couldn't read path /local/domain/0/backend/vbd/38/0/vnd

["campbell+netbsd%mumble.net@localhost via gnats" <gnats-admin%NetBSD.org@localhost>]

>Number:         59975
>Category:       pkg
>Synopsis:       xenstore-read: couldn't read path /local/domain/0/backend/vbd/38/0/vnd
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Feb 08 01:00:01 +0000 2026
>Originator:     Taylor R Campbell
>Release:        netbsd-10, xentools418-20231116nb1
>Organization:
>Environment:
>Description:
When I destroy a domU, I get a useless warning message:

xenhost$ sudo xl destroy 35                                                     
xenstore-read: couldn't read path /local/domain/0/backend/vbd/35/0/vnd          
>How-To-Repeat:
destroy a domU that doesn't have a vnd attached or something
>Fix:
Apply the following patch to redirect output in the shell script (and simplify the failure test):

--- /usr/pkg/share/examples/xen/scripts/block.~1~	2026-02-08 00:55:19.637854549 +0000
+++ /usr/pkg/share/examples/xen/scripts/block	2026-02-08 00:55:45.291761640 +0000
@@ -25,8 +25,7 @@
 case $xstatus in
 6)
 	# device removed
-	vnd=$(xenstore-read "$xpath/vnd" || echo none)
-	if [ $vnd != none ]; then
+	if vnd=$(xenstore-read "$xpath/vnd" 2>/dev/null); then
 		vnconfig -u $vnd
 	fi
 	xenstore-rm $xpath

The rest of the shell script probably needs some serious attention too but I'm trying to get something else done.