[Qemu-block] [PATCH 03/17] iotests: ask qemu for supported formats

[Roman Kagan]

Add helper functions to query the block drivers actually supported by
QEMU using "-drive format=?".  This allows to skip certain tests that
require drivers not built in or whitelisted in QEMU.

Signed-off-by: Roman Kagan <address@hidden>
---
 tests/qemu-iotests/common.rc  | 19 +++++++++++++++++++
 tests/qemu-iotests/iotests.py | 30 +++++++++++++++++++++++++++---
 2 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index 9a65a11026..fe5a4d1cfd 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -493,5 +493,24 @@ _require_command()
     [ -x "$c" ] || _notrun "$1 utility required, skipped this test"
 }
 
+# this test requires support for specific formats
+#
+_require_format()
+{
+    supported_formats=$($QEMU_PROG $QEMU_OPTIONS -drive format=\? 2>&1 | \
+        head -1 | cut -d : -f 2)
+    for f; do
+        found=false
+        for sf in $supported_formats; do
+            if [ "$f" = "$sf" ]; then
+                found=true
+                break
+            fi
+        done
+
+        $found || _notrun "$QEMU_PROG doesn't support format $f"
+    done
+}
+
 # make sure this script returns success
 true
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index e2abf0cb53..698ef2b2c0 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -119,6 +119,17 @@ def qemu_io(*args):
         sys.stderr.write('qemu-io received signal %i: %s\n' % 
(-subp.returncode, ' '.join(args)))
     return output
 
+def qemu_pipe(*args):
+    '''Run qemu with an option to print something and exit (e.g. a help 
option),
+    and return its output'''
+    args = [qemu_prog] + qemu_opts + list(args)
+    subp = subprocess.Popen(args, stdout=subprocess.PIPE,
+                            stderr=subprocess.STDOUT)
+    output = subp.communicate()[0]
+    if subp.returncode < 0:
+        sys.stderr.write('qemu received signal %i: %s\n' % (-subp.returncode, 
' '.join(args)))
+    return output
+
 
 class QemuIoInteractive:
     def __init__(self, *args):
@@ -550,13 +561,26 @@ def verify_cache_mode(supported_cache_modes=[]):
     if supported_cache_modes and (cachemode not in supported_cache_modes):
         notrun('not suitable for this cache mode: %s' % cachemode)
 
+rw_formats = None
+
+def supports_format(format_name):
+    format_message = qemu_pipe('-drive', 'format=?')
+    global rw_formats
+    if rw_formats is None:
+        rw_formats = format_message.splitlines()[0].split(':')[1].split()
+    return format_name in rw_formats
+
+def require_formats(*formats):
+    for fmt in formats:
+        if not supports_format(fmt):
+            notrun('%s does not support format %s' % (qemu_prog, fmt))
+
 def supports_quorum():
-    return 'quorum' in qemu_img_pipe('--help')
+    return supports_format('quorum')
 
 def verify_quorum():
     '''Skip test suite if quorum support is not available'''
-    if not supports_quorum():
-        notrun('quorum support missing')
+    require_formats('quorum')
 
 def main(supported_fmts=[], supported_oses=['linux'], supported_cache_modes=[],
          unsupported_fmts=[]):
-- 
2.14.3