eec2e1d3b1 introduced logic to use the Xwayland
binary discovered via pkg-config.
While the newly introduced checks correctly used the binary from pkg-config,
the actual execution still used the previous PATH-search logic.
`_NET_WM_PID` is unreliable: it is optional and even if set it may
contain PIDs from sandbox namespaces or remote systems.
Prefer XRes v1.2 QueryClientIds method which returns PIDs as seen by the
Xwayland server.
wlroots' dependency on this library doesn't change the features
exposed to compositors. It's purely a wlroots implementation detail.
Thus downstream compositors shouldn't really care about it.
Introduce an "internal_features" dictionary to store the status of
such internal dependencies.
This dependency is already required by many other widely used X11
programs, such as i3, Qt, and other XWMs. So it should be available
on most systems.
X11 support can be pretty broken without xcb-icccm, with focus issues
for instance. Let's just remove this --please-break-my-desktop footgun
option.
Some X11 clients (e.g. Chromium, sxiv) don't set WM_HINTS. The spec
says:
> Window managers are free to assume convenient values for all fields of the
> WM_HINTS property if a window is mapped without one.
Our wlr_xwayland_icccm_input_model function assumes missing WM_HINTS
means the window doesn't want input, but this is incorrect. Assume the
window wants input unless it explicitly opts-out by setting WM_HINTS.
Closes: https://github.com/swaywm/sway/issues/6107
Instead of walking PATH like a previous proposal [1], this one
checks that the Xwayland path specified in the pkg-config file
exists.
I think this is a reasonable compromise:
- Users that don't have Xwayland installed system-wide won't get
a bogus DISPLAY env variable set up.
- Users that have WLR_XWAYLAND set won't be affected by this check.
- Users that have Xwayland installed system-wide and a different
Xwayland in their PATH still get their custom Xwayland.
- Users that don't have Xwayland installed system-wide but have it
somewhere else in PATH are left out. But this is pretty niche,
and they can just set WLR_XWAYLAND.
[1]: https://github.com/swaywm/wlroots/pull/2314
Check that the pkg-config file is available. This will be required
in the future to check whether xwayland supports features such as
-listenfd, -initfd or -verbose.
If there's no pkg-config file, check that the Xwayland executable
is available.
This effectively makes our relationship with xwayland closer to what
a dynamic library is: checked at build-time, but can be overridden
at run-time.
Our internal state machine gets screwed up if selection events are not
monotonically increasing in time, and we can enter a self-copy loop from
the proxy window that exhausts all pipes.
Snippet of logs when this occurs:
00:00:46.238 [wlr] [xwayland/selection/incoming.c:487] XCB_XFIXES_SELECTION_NOTIFY (selection=277, owner=4194626)
00:00:46.238 [wlr] [xwayland/selection/incoming.c:487] XCB_XFIXES_SELECTION_NOTIFY (selection=277, owner=2097153)
00:00:46.238 [wlr] [xwayland/selection/outgoing.c:378] XCB_SELECTION_REQUEST (time=58979563 owner=2097153, requestor=2097153 selection=277, target=279, property=278)
00:00:46.238 [wlr] [xwayland/selection/outgoing.c:397] ignoring old request from timestamp 58979563; expecting > 58979563
00:00:46.238 [wlr] [xwayland/selection/outgoing.c:29] SendEvent destination=2097153 SelectionNotify(31) time=58979563 requestor=2097153 selection=277 target=279 property=0
00:00:46.238 [wlr] [xwayland/selection/incoming.c:453] XCB_SELECTION_NOTIFY (selection=277, property=0, target=279)
Note that 2097153 is `selection->window`, and 4194626 is Emacs.
The race occurs if the selection owner changes back to our proxy window
between when we get `XCB_XFIXES_SELECTION_NOTIFY` for Emacs and when we
call `xcb_convert_selection` in `incoming.c:source_send` -- the
ConvertSelection request can end up hitting our proxy window, but the
timestamp will be rejected.
Fixes#2192.
There seems to be no reason why we can't service multiple Wayland-to-X11
transfers concurrently, so long as they are to different windows (or
possibly, same windows but different target properties?)
This commit removes the queuing logic, but retains the request
de-duplication from #2428.
Previously, the clipboard and primary selections shared the same window.
This was racey, and could have led to pasting failures.
On xfixes selection owner change notification, the logic for requesting
the supported mimetypes of the new owner's selection looks like:
xcb_convert_selection(
xwm->xcb_conn,
selection->window,
selection->atom,
xwm->atoms[TARGETS],
xwm->atoms[WL_SELECTION],
selection->timestamp
);
This means ask the selection owner to write its TARGETS for the
`selection->atom` selection (one of PRIMARY, CLIPBOARD, DND_SELECTION)
to `selection->window`'s WL_SELECTION atom.
However, `selection->window` is shared for both PRIMARY and CLIPBOARD
selections, and WL_SELECTION is used as the target atom in both cases.
So, there's a race when both selections change at the same time.
The CLIPBOARD selection might support mimetypes {A, B, C}, and the
PRIMARY only {A, B}. If the ConvertSelection requests/responses "cross
on the wire", so to speak, wlroots can end up believing that the PRIMARY
selection also supports C.
A Wayland client may then ask for the PRIMARY selection in C format,
which will fail with "convert selection failed".
This commit fixes this by using a separate window for PRIMARY and
CLIPBOARD target requests, so that WL_SELECTION can be used as the
target atom in both cases.
This commit introduces logic for using a new X11 window for each
incoming transfer, rather than having a global window for each selection
source.
This eliminates a whole class of bugs involving multiple concurrent
incoming transfers.
For now, we retain the outgoing transfer queue, and the selection
source-specific windows to support it. Source-specific windows are no
longer used in the incoming path, and will be removed in a future PR.
Refs #1497.
Previously, Xwayland could restart, and we'd get events for transfers
pointing to the previous (now freed) xwm instance. This led to
use-after-free segfaults.
Closes#2565.
This will hopefully be fixed in the future by having separate windows
for each X11-to-Wayland transfer, but until then, let's avoid a
compositor crash.
Previously, `transfer->incr` was being cleared on the next selection.
However, if the next selection was *also* incremental, it's possible
that `xwm_handle_selection_property_notify` would route us to
`xwm_get_incr_chunk` instead of `xwm_selection_get_data`.
Apart from reducing duplication, this has the positive side-effect of
allowing all deallocs to use
`xwm_selection_transfer_destroy_property_reply`, as opposed to the
latter and a mix of ad-hoc `free`s.
Previously, if the Wayland client died before an incremental transfer
was complete, the logs would be spammed by "write error to target fd" as
wlroots entered some control flow wherein it'd continually try
scheduling further writes to the already-dead pipe.
This commit contains no behavioral changes, but introduces explicit
handling for draining the X11 selection in case of Wayland client death.
If `xwm_data_source_write` failed, it's failed permanently. In fact, a
failing `xwm_data_source_write` sets `transfer->property_reply` to
null as part of its error handling.
Instead of relying on an indirect check (whether
`transfer->property_reply` is still non-null), explicitly use the return
value from `xwm_data_source_write`.
The `fd` is marked `O_NONBLOCK`, so `write` will never spuriously return
`EINTR`. Therefore, `write` failing is permanent, and we can return 0 to
make the return value meaningful.
wlroots would log "Unhandled NET_WM_STATE property change" log
messages for atoms we know about. Simplify the code structure
and remove these extra messages.
Previously, wlr_xwm_selection_transfer.source_fd meant:
- the source of data in a Wayland -> X11 copy (good)
- the destination of data in a X11 -> Wayland copy (confusing)
This made reading through xwayland/selection/incoming.c difficult: in
many places, "source" actually means "destination".
Previously, any error would be masked by an internal isatty call:
24:31:48.174 [DEBUG] [wlr] [xwayland/selection/incoming.c:386] XCB_SELECTION_NOTIFY (selection=277, property=278, target=256)
24:31:48.174 [ERROR] [wlr] [xwayland/selection/incoming.c:30] write error to target fd: Inappropriate ioctl for device
In certain situations windows can have their input field set to false
but still expect to receive input focus by passively listening to key
presses via a parent window. The ICCCM specification outlines how focus
should be given to clients.
Further reading: https://tronche.com/gui/x/icccm/sec-4.html#s-4.1.7
Relates to #2604
Xwayland has its own special handling for signals like SIGSEGV/SIGABRT.
Instead of leaving the job to the OS, it tries to walk up the call stack
(badly, because a lot of information is missing), print the stack trace
to stdout, then exit(1). This is very annoying because it prevents
Xwayland crashes from being easily debugged.
Xwayland has a flag "-core" that aborts instead of exiting. This allows
the OS to generate a coredump. It's far from perfect but better than
nothing, I guess.
We already mostly did this, but there were a couple of branches
(`calloc` failures) where we'd bail without letting the other side know.
Refs swaywm/sway#4007. Likely not going to be a real improvement there
(if `calloc` fails you're already pretty screwed), but it does address a
theoretical possibility.
