tests: pull qemu-nbd iotest helpers into common.nbd file

The helpers for starting/stopping qemu-nbd in 058 will be useful in
other test cases, so move them into a common.nbd file.
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>
Message-Id: <20181116155325.22428-4-berrange@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
[eblake: fix shell quoting]
Signed-off-by: NEric Blake <eblake@redhat.com>

tests/qemu-iotests/058

@@ -28,55 +28,19 @@ echo "QA output created by $seq"
 
 status=1	# failure is the default!
 
-nbd_unix_socket=$TEST_DIR/test_qemu_nbd_socket
-nbd_snapshot_img="nbd:unix:$nbd_unix_socket"
-rm -f "${TEST_DIR}/qemu-nbd.pid"
-
-_cleanup_nbd()
-{
-    local NBD_SNAPSHOT_PID
-    if [ -f "${TEST_DIR}/qemu-nbd.pid" ]; then
-        read NBD_SNAPSHOT_PID < "${TEST_DIR}/qemu-nbd.pid"
-        rm -f "${TEST_DIR}/qemu-nbd.pid"
-        if [ -n "$NBD_SNAPSHOT_PID" ]; then
-            kill "$NBD_SNAPSHOT_PID"
-        fi
-    fi
-    rm -f "$nbd_unix_socket"
-}
-
-_wait_for_nbd()
-{
-    for ((i = 0; i < 300; i++))
-    do
-        if [ -r "$nbd_unix_socket" ]; then
-            return
-        fi
-        sleep 0.1
-    done
-    echo "Failed in check of unix socket created by qemu-nbd"
-    exit 1
-}
-
-converted_image=$TEST_IMG.converted
-
 _export_nbd_snapshot()
 {
-    _cleanup_nbd
-    $QEMU_NBD -v -t -k "$nbd_unix_socket" "$TEST_IMG" -l $1 &
-    _wait_for_nbd
+    nbd_server_start_unix_socket "$TEST_IMG" -l $1
 }
 
 _export_nbd_snapshot1()
 {
-    _cleanup_nbd
-    $QEMU_NBD -v -t -k "$nbd_unix_socket" "$TEST_IMG" -l snapshot.name=$1 &
-    _wait_for_nbd
+    nbd_server_start_unix_socket "$TEST_IMG" -l snapshot.name=$1
 }
 
 _cleanup()
 {
-    _cleanup_nbd
+    nbd_server_stop
     _cleanup_test_img
     rm -f "$converted_image"
 }
@@ -86,6 +50,7 @@ trap "_cleanup; exit \$status" 0 1 2 3 15
 . ./common.rc
 . ./common.filter
 . ./common.pattern
+. ./common.nbd
 
 _supported_fmt qcow2
 _supported_proto file
@@ -94,6 +59,10 @@ _require_command QEMU_NBD
 # Internal snapshots are (currently) impossible with refcount_bits=1
 _unsupported_imgopts 'refcount_bits=1[^0-9]'
 
+nbd_snapshot_img="nbd:unix:$nbd_unix_socket"
+
+converted_image=$TEST_IMG.converted
+
 # Use -f raw instead of -f $IMGFMT for the NBD connection
 QEMU_IO_NBD="$QEMU_IO -f raw --cache=$CACHEMODE"
 

tests/qemu-iotests/common.nbd

+#!/bin/bash
+# -*- shell-script-mode -*-
+#
+# Helpers for NBD server related config
+#
+# Copyright (C) 2018 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+nbd_unix_socket="${TEST_DIR}/qemu-nbd.sock"
+nbd_pid_file="${TEST_DIR}/qemu-nbd.pid"
+
+function nbd_server_stop()
+{
+    local NBD_PID
+    if [ -f "$nbd_pid_file" ]; then
+        read NBD_PID < "$nbd_pid_file"
+        rm -f "$nbd_pid_file"
+        if [ -n "$NBD_PID" ]; then
+            kill "$NBD_PID"
+        fi
+    fi
+    rm -f "$nbd_unix_socket"
+}
+
+function nbd_server_wait_for_unix_socket()
+{
+    for ((i = 0; i < 300; i++))
+    do
+        if [ -r "$nbd_unix_socket" ]; then
+            return
+        fi
+        sleep 0.1
+    done
+    echo "Failed in check of unix socket created by qemu-nbd"
+    exit 1
+}
+
+function nbd_server_start_unix_socket()
+{
+    nbd_server_stop
+    $QEMU_NBD -v -t -k "$nbd_unix_socket" "$@" &
+    nbd_server_wait_for_unix_socket
+}