xserver: Branch 'master'

[Adam Jackson]

 hw/xwayland/xwayland.c |    7 +++++++
 1 file changed, 7 insertions(+)

New commits:
commit 98edb9a35e2cdd61355656b82975d7f2b6a9f0e6
Author: Lyude Paul <lyude at redhat.com>
Date:   Tue Feb 6 12:41:47 2018 -0500

    xwayland: Don't process cursor warping without an xwl_seat
    
    Unfortunately, on my machine Xwayland immediately crashes when I try to
    start it. gdb backtrace:
    
     #0  0x00007ffff74f0e79 in wl_proxy_marshal () from target:/lib64/libwayland-client.so.0
     #1  0x0000000000413172 in zwp_confined_pointer_v1_destroy (zwp_confined_pointer_v1=0x700000000)
         at hw/xwayland/Xwayland at exe/pointer-constraints-unstable-v1-client-protocol.h:612
     #2  0x0000000000418bc0 in xwl_seat_destroy_confined_pointer (xwl_seat=0x8ba2a0)
         at /home/lyudess/Projects/xserver/hw/xwayland/xwayland-input.c:2839
     #3  0x0000000000418c09 in xwl_seat_unconfine_pointer (xwl_seat=0x8ba2a0)
         at /home/lyudess/Projects/xserver/hw/xwayland/xwayland-input.c:2849
     #4  0x0000000000410d97 in xwl_cursor_confined_to (device=0xa5a000, screen=0x8b9d80, window=0x9bdb70)
         at /home/lyudess/Projects/xserver/hw/xwayland/xwayland.c:328
     #5  0x00000000004a8571 in ConfineCursorToWindow (pDev=0xa5a000, pWin=0x9bdb70, generateEvents=1,
         confineToScreen=0) at /home/lyudess/Projects/xserver/dix/events.c:900
     #6  0x00000000004a94b7 in ScreenRestructured (pScreen=0x8b9d80)
         at /home/lyudess/Projects/xserver/dix/events.c:1387
     #7  0x0000000000502386 in RRScreenSizeNotify (pScreen=0x8b9d80)
         at /home/lyudess/Projects/xserver/randr/rrscreen.c:160
     #8  0x000000000041a83c in update_screen_size (xwl_output=0x8e7670, width=3840, height=2160)
         at /home/lyudess/Projects/xserver/hw/xwayland/xwayland-output.c:203
     #9  0x000000000041a9f0 in apply_output_change (xwl_output=0x8e7670)
         at /home/lyudess/Projects/xserver/hw/xwayland/xwayland-output.c:252
     #10 0x000000000041aaeb in xdg_output_handle_done (data=0x8e7670, xdg_output=0x8e7580)
         at /home/lyudess/Projects/xserver/hw/xwayland/xwayland-output.c:307
     #11 0x00007ffff50e9d1e in ffi_call_unix64 () at ../src/x86/unix64.S:76
     #12 0x00007ffff50e968f in ffi_call (cif=<optimized out>, fn=<optimized out>, rvalue=<optimized out>,
         avalue=<optimized out>) at ../src/x86/ffi64.c:525
     #13 0x00007ffff74f3d8b in wl_closure_invoke () from target:/lib64/libwayland-client.so.0
     #14 0x00007ffff74f0928 in dispatch_event.isra () from target:/lib64/libwayland-client.so.0
     #15 0x00007ffff74f1be4 in wl_display_dispatch_queue_pending () from target:/lib64/libwayland-client.so.0
     #16 0x00007ffff74f200b in wl_display_roundtrip_queue () from target:/lib64/libwayland-client.so.0
     #17 0x0000000000418cad in InitInput (argc=12, argv=0x7fffffffd9c8)
         at /home/lyudess/Projects/xserver/hw/xwayland/xwayland-input.c:2867
     #18 0x00000000004a20e3 in dix_main (argc=12, argv=0x7fffffffd9c8, envp=0x7fffffffda30)
         at /home/lyudess/Projects/xserver/dix/main.c:250
     #19 0x0000000000420cb2 in main (argc=12, argv=0x7fffffffd9c8, envp=0x7fffffffda30)
        at /home/lyudess/Projects/xserver/dix/stubmain.c:34
    
    This appears to be the result of xwl_cursor_confined_to() and
    xwl_screen_get_default_seat(). While not against protocol, mutter ends
    up sending xdg_output before wl_seat. xwl_screen_get_default_seat()
    makes the naïve assumption that we always have a valid seat, we end up
    returning a pointer to the empty list itself instead of an actual seat
    and causing ourselves to segfault.
    
    So, actually return NULL in xwl_screen_get_default_seat() if the seat
    list is empty, and skip any pointer confinement processing in
    xwl_cursor_confined_to() when we don't have a seat setup yet.
    
    Signed-off-by: Lyude Paul <lyude at redhat.com>
    Reviewed-by: Adam Jackson <ajax at redhat.com>

diff --git a/hw/xwayland/xwayland.c b/hw/xwayland/xwayland.c
index 19aa14a47..9b1d85674 100644
--- a/hw/xwayland/xwayland.c
+++ b/hw/xwayland/xwayland.c
@@ -265,6 +265,9 @@ xwl_close_screen(ScreenPtr screen)
 static struct xwl_seat *
 xwl_screen_get_default_seat(struct xwl_screen *xwl_screen)
 {
+    if (xorg_list_is_empty(&xwl_screen->seat_list))
+        return NULL;
+
     return container_of(xwl_screen->seat_list.prev,
                         struct xwl_seat,
                         link);
@@ -324,6 +327,10 @@ xwl_cursor_confined_to(DeviceIntPtr device,
     if (!xwl_seat)
         xwl_seat = xwl_screen_get_default_seat(xwl_screen);
 
+    /* xwl_seat hasn't been setup yet, don't do anything just yet */
+    if (!xwl_seat)
+        return;
+
     if (window == screen->root) {
         xwl_seat_unconfine_pointer(xwl_seat);
         return;