vdagentd: support fake uinput

This is used with Xspice. Fake means we open a pipe for write only, and
don't do any ioctls on it. Specifically it means the axis and buttons
have to be coordinated for now with Xspice (xf86-video-qxl).

Signed-off-by: Alon Levy <alevy@redhat.com>

3 files changed, 21 insertions, 6 deletions

diff --git a/src/vdagentd-uinput.c b/src/vdagentd-uinput.c
index a415f9c..47e1b45 100644
--- a/src/vdagentd-uinput.c
+++ b/src/vdagentd-uinput.c
@@ -42,12 +42,13 @@ struct vdagentd_uinput {
     struct vdagentd_guest_xorg_resolution *screen_info;
     int screen_count;
     VDAgentMouseState last;
+    int fake;
 };
 
 struct vdagentd_uinput *vdagentd_uinput_create(const char *devname,
     int width, int height,
     struct vdagentd_guest_xorg_resolution *screen_info, int screen_count,
-    int debug)
+    int debug, int fake)
 {
     struct vdagentd_uinput *uinput;
 
@@ -58,6 +59,7 @@ struct vdagentd_uinput *vdagentd_uinput_create(const char *devname,
     uinput->devname = devname;
     uinput->fd      = -1; /* Gets opened by vdagentd_uinput_update_size() */
     uinput->debug   = debug;
+    uinput->fake    = fake;
 
     vdagentd_uinput_update_size(&uinput, width, height,
                                 screen_info, screen_count);
@@ -119,13 +121,18 @@ void vdagentd_uinput_update_size(struct vdagentd_uinput **uinputp,
         return;
 #endif
 
-    uinput->fd = open(uinput->devname, O_RDWR);
+    uinput->fd = open(uinput->devname, uinput->fake ? O_WRONLY : O_RDWR);
     if (uinput->fd == -1) {
         syslog(LOG_ERR, "open %s: %m", uinput->devname);
         vdagentd_uinput_destroy(uinputp);
         return;
     }
 
+    if (uinput->fake) {
+        /* fake device doesn't understand any ioctls and only writes events */
+        return;
+    }
+
     rc = write(uinput->fd, &device, sizeof(device));
     if (rc != sizeof(device)) {
         syslog(LOG_ERR, "write %s: %m", uinput->devname);
diff --git a/src/vdagentd-uinput.h b/src/vdagentd-uinput.h
index 81f0376..b9bd9f1 100644
--- a/src/vdagentd-uinput.h
+++ b/src/vdagentd-uinput.h
@@ -30,7 +30,7 @@ struct vdagentd_uinput;
 struct vdagentd_uinput *vdagentd_uinput_create(const char *devname,
     int width, int height,
     struct vdagentd_guest_xorg_resolution *screen_info, int screen_count,
-    int debug);
+    int debug, int fake);
 void vdagentd_uinput_destroy(struct vdagentd_uinput **uinputp);
 
 void vdagentd_uinput_do_mouse(struct vdagentd_uinput **uinputp,
diff --git a/src/vdagentd.c b/src/vdagentd.c
index 2288671..cfb7acc 100644
--- a/src/vdagentd.c
+++ b/src/vdagentd.c
@@ -58,6 +58,7 @@ static const char *portdev = "/dev/virtio-ports/com.redhat.spice.0";
 static const char *vdagentd_socket = VDAGENTD_SOCKET;
 static const char *uinput_device = "/dev/uinput";
 static int debug = 0;
+static int uinput_fake = 0;
 static struct udscs_server *server = NULL;
 static struct vdagent_virtio_port *virtio_port = NULL;
 static GHashTable *active_xfers = NULL;
@@ -317,7 +318,8 @@ int virtio_port_read_complete(
                                                 agent_data->height,
                                                 agent_data->screen_info,
                                                 agent_data->screen_count,
-                                                debug > 1);
+                                                debug > 1,
+                                                uinput_fake);
             if (!uinput) {
                 syslog(LOG_CRIT, "Fatal uinput error");
                 retval = 1;
@@ -488,7 +490,8 @@ static void check_xorg_resolution(void)
                                             agent_data->height,
                                             agent_data->screen_info,
                                             agent_data->screen_count,
-                                            debug > 1);
+                                            debug > 1,
+                                            uinput_fake);
         else
             vdagentd_uinput_update_size(&uinput,
                                         agent_data->width,
@@ -867,6 +870,11 @@ int main(int argc, char *argv[])
         }
     }
 
+    if (strncmp(uinput_device, "/dev", 4) != 0) {
+        syslog(LOG_INFO, "using fake uinput");
+        uinput_fake = 1;
+    }
+
     memset(&act, 0, sizeof(act));
     act.sa_flags = SA_RESTART;
     act.sa_handler = quit_handler;
@@ -899,7 +907,7 @@ int main(int argc, char *argv[])
 
 #ifdef WITH_STATIC_UINPUT
     uinput = vdagentd_uinput_create(uinput_device, 1024, 768, NULL, 0,
-                                    debug > 1);
+                                    debug > 1, uinput_fake);
     if (!uinput) {
         udscs_destroy_server(server);
         return 1;