[Libguestfs] [nbdkit PATCH] tests: Don't strand hung nbdkit processes

[Eric Blake]

We've recently been hitting a transient hung rpm build when using make
4.3, due to a bug in test-nbd-tls-psk.sh.  We're still trying to
isolate the correct fix for that bug (it might be in the nbd plugin
proper, but more likely is an issue in libnbd's tls handling of
connection close), but in the meantime, this patch should at least
cause a graceful fail rather than make hanging due to an nbdkit
process that has hung.

Signed-off-by: Eric Blake <eblake at redhat.com>
---
 tests/functions.sh.in | 31 ++++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/tests/functions.sh.in b/tests/functions.sh.in
index 8406fcf9..e483505e 100644
--- a/tests/functions.sh.in
+++ b/tests/functions.sh.in
@@ -85,8 +85,8 @@ requires_ipv6_loopback ()
     # instead.  It's very unlikely that port 1 is open.
     if LANG=C qemu-img info "nbd:[::1]:1" |& \
        grep -sq "Address family for hostname not supported"; then
-	echo "$0: IPv6 loopback is not available, skipping this test"
-	exit 77
+        echo "$0: IPv6 loopback is not available, skipping this test"
+        exit 77
     fi
 }

@@ -139,7 +139,32 @@ start_nbdkit ()
     fi

     # Kill nbdkit on exit.
-    cleanup_fn kill "$(cat "$pidfile")"
+    cleanup_fn kill_nbdkit "$(cat "$pidfile")"
+}
+
+# kill_nbdkit pid
+#
+# End the nbkdit process that created pidfile.  Exit this script with an
+# error if nbdkit does not gracefully shutdown in a timely manner.
+kill_nbdkit ()
+{
+    local pid=$1 i
+
+    # Start with SIGTERM, and wait for graceful exit
+    kill $pid
+    for i in {1..60}; do
+        if ! kill -0 $pid 2>/dev/null; then
+            break
+        fi
+        sleep 1
+    done
+    # If nbdkit has not exited, try SIGKILL and fail the test
+    if test $i = 60; then
+        echo "error: nbdkit pid $pid failed to respond to SIGTERM"
+        kill -9 $pid
+        # Append our failure after other cleanups
+        cleanup_fn exit 1
+    fi
 }

 # foreach_plugin f [args]
-- 
2.25.1