[Spice-devel] [PATCH spice-server v2 1/2] test-stream-device: Better Qemu emulation for data reading

[Frediano Ziglio]

Qemu does not trigger a new data read if we don't read all data in
the buffer.

Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
---
 server/stream-device.c            |  9 ++++++++
 server/tests/test-stream-device.c | 43 +++++++++++++++++++++++++++++++++++++--
 2 files changed, 50 insertions(+), 2 deletions(-)

Changes since v1:
- avoid an inifinite loop, test added.

diff --git a/server/stream-device.c b/server/stream-device.c
index 4eaa959b..897fc665 100644
--- a/server/stream-device.c
+++ b/server/stream-device.c
@@ -123,6 +123,15 @@ stream_device_read_msg_from_dev(RedCharDevice *self, SpiceCharDeviceInstance *si
         dev->hdr_pos = 0;
     }
 
+    if (handled || dev->has_error) {
+        // Qemu put the device on blocking state if we don't read all data
+        // so schedule another read.
+        // We arrive here if we processed that entire message or we
+        // got an error, try to read another message or discard the
+        // wrong data
+        red_char_device_wakeup(self);
+    }
+
     return NULL;
 }
 
diff --git a/server/tests/test-stream-device.c b/server/tests/test-stream-device.c
index 656bf56b..85c7ab1a 100644
--- a/server/tests/test-stream-device.c
+++ b/server/tests/test-stream-device.c
@@ -23,6 +23,7 @@
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <unistd.h>
 
 #include <spice/protocol.h>
 #include <spice/stream-device.h>
@@ -68,8 +69,12 @@ static int vmc_read(SPICE_GNUC_UNUSED SpiceCharDeviceInstance *sin,
     pos += ret;
     // kick off next message read
     // currently Qemu kicks the device so we need to do it manually
-    // here
-    spice_server_char_device_wakeup(&vmc_instance);
+    // here. If not all data are read the device goes into blocking
+    // state and we get the wake only when we read from the device
+    // again
+    if (pos >= *message_sizes_curr) {
+        spice_server_char_device_wakeup(&vmc_instance);
+    }
     return ret;
 }
 
@@ -177,11 +182,45 @@ static void test_stream_device(void)
     basic_event_loop_destroy();
 }
 
+static void test_stream_device_unfinished(void)
+{
+    uint8_t *p = message;
+    SpiceCoreInterface *core = basic_event_loop_init();
+    Test *test = test_new(core);
+
+    pos = 0;
+    message_sizes_curr = message_sizes;
+    message_sizes_end = message_sizes;
+
+    // this long and not finished message should not cause an inifinite loop
+    p = add_stream_hdr(p, STREAM_TYPE_DATA, 100000);
+    *message_sizes_end = p - message;
+    ++message_sizes_end;
+
+    vmc_instance.base.sif = &vmc_interface.base;
+    spice_server_add_interface(test->server, &vmc_instance.base);
+
+    // we need to open the device and kick the start
+    // the alarm is to avoid program to stuck
+    alarm(5);
+    spice_server_port_event(&vmc_instance, SPICE_PORT_EVENT_OPENED);
+    spice_server_char_device_wakeup(&vmc_instance);
+    alarm(0);
+
+    // we should read all data
+    g_assert(message_sizes_curr - message_sizes == 1);
+
+    test_destroy(test);
+    basic_event_loop_destroy();
+}
+
+
 int main(int argc, char *argv[])
 {
     g_test_init(&argc, &argv, NULL);
 
     g_test_add_func("/server/stream-device", test_stream_device);
+    g_test_add_func("/server/stream-device-unfinished", test_stream_device_unfinished);
 
     return g_test_run();
 }
-- 
2.14.3