[libvirt] [PATCH v1 05/11] qemu: command: Fix building of the SDL display command line

[Erik Skultety]

QEMU uses a shorthand '-sdl' which maps to '-display sdl'. However, if
there are any options to be passed to SDL, the full command version must
be used. Everything seemingly worked for us until commit 5038b300437
introduced OpenGL support for SDL and added ',gl=on/off' option which as
mentioned above could have never worked with the shorthand version of
the command. Indeed starting a domain with an SDL display and OpenGL
enabled, QEMU produces a rather cryptic error:

-sdl: Could not open 'gl=on': No such file or directory

This patch provides fixes to both the SDL cmdline generation and the
test suite.

Signed-off-by: Erik Skultety <eskultet at redhat.com>
---
 src/qemu/qemu_command.c                             | 19 +++++++++++--------
 tests/qemuxml2argvdata/graphics-sdl-fullscreen.args |  2 +-
 tests/qemuxml2argvdata/graphics-sdl.args            |  2 +-
 tests/qemuxml2argvdata/video-virtio-gpu-sdl-gl.args |  2 +-
 4 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 1e5d7f9ccf..195d03e373 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -7722,7 +7722,6 @@ qemuBuildGraphicsSDLCommandLine(virQEMUDriverConfigPtr cfg ATTRIBUTE_UNUSED,
 {
     int ret = -1;
     virBuffer opt = VIR_BUFFER_INITIALIZER;
-    const char *optContent;
 
     if (graphics->data.sdl.xauth)
         virCommandAddEnvPair(cmd, "XAUTHORITY", graphics->data.sdl.xauth);
@@ -7738,22 +7737,26 @@ qemuBuildGraphicsSDLCommandLine(virQEMUDriverConfigPtr cfg ATTRIBUTE_UNUSED,
     virCommandAddEnvPassBlockSUID(cmd, "QEMU_AUDIO_DRV", NULL);
     virCommandAddEnvPassBlockSUID(cmd, "SDL_AUDIODRIVER", NULL);
 
-    virCommandAddArg(cmd, "-sdl");
+    virCommandAddArg(cmd, "-display");
+    virBufferAddLit(&opt, "sdl");
 
-    if (graphics->data.sdl.gl == VIR_TRISTATE_BOOL_YES) {
+    if (graphics->data.sdl.gl != VIR_TRISTATE_BOOL_ABSENT) {
         if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_SDL_GL)) {
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
-                           _("This QEMU doesn't support SDL OpenGL"));
+                           _("OpenGL for SDL is not supported with this QEMU "
+                             "binary"));
             goto cleanup;
         }
 
-        virBufferAsprintf(&opt, "gl=%s",
+        virBufferAsprintf(&opt, ",gl=%s",
                           virTristateSwitchTypeToString(graphics->data.sdl.gl));
+
     }
 
-    optContent = virBufferCurrentContent(&opt);
-    if (optContent && STRNEQ(optContent, ""))
-        virCommandAddArgBuffer(cmd, &opt);
+    if (virBufferCheckError(&opt) < 0)
+        goto cleanup;
+
+    virCommandAddArgBuffer(cmd, &opt);
 
     ret = 0;
  cleanup:
diff --git a/tests/qemuxml2argvdata/graphics-sdl-fullscreen.args b/tests/qemuxml2argvdata/graphics-sdl-fullscreen.args
index 2da9d1e327..0741baa039 100644
--- a/tests/qemuxml2argvdata/graphics-sdl-fullscreen.args
+++ b/tests/qemuxml2argvdata/graphics-sdl-fullscreen.args
@@ -25,5 +25,5 @@ server,nowait \
 -drive file=/dev/HostVG/QEMUGuest1,format=raw,if=none,id=drive-ide0-0-0 \
 -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 \
 -full-screen \
--sdl \
+-display sdl \
 -vga cirrus
diff --git a/tests/qemuxml2argvdata/graphics-sdl.args b/tests/qemuxml2argvdata/graphics-sdl.args
index 29a0a3d823..2553679738 100644
--- a/tests/qemuxml2argvdata/graphics-sdl.args
+++ b/tests/qemuxml2argvdata/graphics-sdl.args
@@ -24,5 +24,5 @@ server,nowait \
 -usb \
 -drive file=/dev/HostVG/QEMUGuest1,format=raw,if=none,id=drive-ide0-0-0 \
 -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 \
--sdl \
+-display sdl \
 -vga std
diff --git a/tests/qemuxml2argvdata/video-virtio-gpu-sdl-gl.args b/tests/qemuxml2argvdata/video-virtio-gpu-sdl-gl.args
index 4172320ede..f8610e53b0 100644
--- a/tests/qemuxml2argvdata/video-virtio-gpu-sdl-gl.args
+++ b/tests/qemuxml2argvdata/video-virtio-gpu-sdl-gl.args
@@ -23,6 +23,6 @@ server,nowait \
 -drive file=/var/lib/libvirt/images/QEMUGuest1,format=qcow2,if=none,\
 id=drive-ide0-0-0,cache=none \
 -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 \
--sdl gl=on \
+-display sdl,gl=on \
 -device virtio-gpu-pci,id=video0,virgl=on,bus=pci.0,addr=0x2 \
 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3
-- 
2.14.4