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Thomas Hebb a235794a96 input/seat: unset has_focus when focus_stack becomes empty
We currently track the focus of a seat in two ways: we use a list called
focus_stack to track the order in which nodes have been focused, with
the first node representing what's currently focused, and we use a
variable called has_focus to indicate whether anything has focus--i.e.
whether we should actually treat that first node as focused at any given
time.

In a number of places, we treat has_focus as implying that a focused
node exists. If it's true, we attempt to dereference the return value of
seat_get_focus(), our helper function for getting the first node in
focus_list, with no further checks. But this isn't quite correct with
the current implementation of seat_get_focus(): not only does it return
NULL when has_focus is false, it also returns NULL when focus_stack
contains no items.

In most cases, focus_stack never becomes empty and so this doesn't
matter at all. Since focus_stack stores a history of focused nodes, we
rarely remove nodes from it. The exception to this is when a node itself
goes away. In that case, we call seat_node_destroy() to remove it from
focus_stack and free it. But we don't unset has_focus if we've removed
the final node! This lets us get into a state where has_focus is true
but seat_get_focus() returns NULL, leading to a segfault when we try to
dereference it.

Fix the issue both by updating has_focus in seat_node_destroy() and by
adding an assertion in seat_get_focus() that ensures focus_stack and
has_focus are in sync, which will make it easier to track down similar
issues in the future.

Fixes #6395.

[1] There's some discussion in #1585 from when this was implemented
about whether has_focus is actually necessary; it's possible we could
remove it entirely, but for the moment this is the architecture we have.

(cherry picked from commit 921b0a863382b70234aeb4bd589c10328e9ff042)
2022-01-07 15:09:24 +01:00
.builds Update URL to wlroots project (GitHub->GitLab) 2021-11-02 08:43:24 +01:00
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assets License wallpapers as CC-0 2019-12-16 14:35:58 -05:00
client cairo: Replace <cairo/cairo.h> by <cairo.h> 2021-05-10 10:28:32 +02:00
common Avoid unecessary font metric calculations 2021-09-20 09:25:47 +02:00
completions i3-compat: add GET_BINDING_STATE IPC command 2020-06-14 00:55:14 -04:00
contrib grimshot: Exit 1 on cancellation 2021-07-10 13:03:42 +02:00
include output: change output::destroy to output::disable 2021-12-17 14:39:48 +01:00
protocols Add support for linux-dmabuf surface hints 2021-12-13 09:59:33 -06:00
sway input/seat: unset has_focus when focus_stack becomes empty 2022-01-07 15:09:24 +01:00
swaybar swaybar: fix errno handling in status_handle_readable 2021-12-23 12:16:37 +01:00
swaymsg refactor: use JSON_MAX_DEPTH everywhere 2021-10-25 10:18:40 +02:00
swaynag swaynag: remove xdg-output logic 2021-12-13 20:17:20 -06:00
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.gitignore Allocate minimum size necessary in pango text functions. (#3473) 2019-01-20 15:03:30 +01:00
config.in config.in: use swaynag -B instead of -b 2021-10-17 21:30:33 +02:00
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LICENSE MIT license 2017-01-06 13:45:48 -05:00
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meson_options.txt Add meson options to enable/disable swaybar and swaynag 2021-07-21 18:24:09 +02:00
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sway.desktop Update language in sway.desktop & sway(1) 2019-03-10 15:09:52 -04:00

sway

English - 日本語 - Français - Українська - Español - Polski - 中文-简体 - Deutsch - Nederlands - Русский - 中文-繁體 - Português - Dansk - 한국어 - Română - Magyar - Türkçe - فارسی - Ελληνικά

sway is an i3-compatible Wayland compositor. Read the FAQ. Join the IRC channel (#sway on irc.libera.chat).

Release Signatures

Releases are signed with E88F5E48 and published on GitHub.

Installation

From Packages

Sway is available in many distributions. Try installing the "sway" package for yours.

Compiling from Source

Check out this wiki page if you want to build the HEAD of sway and wlroots for testing or development.

Install dependencies:

  • meson *
  • wlroots
  • wayland
  • wayland-protocols *
  • pcre
  • json-c
  • pango
  • cairo
  • gdk-pixbuf2 (optional: system tray)
  • scdoc (optional: man pages) *
  • git (optional: version info) *

* Compile-time dep

Run these commands:

meson build/
ninja -C build/
sudo ninja -C build/ install

On systems without logind nor seatd, you need to suid the sway binary:

sudo chmod a+s /usr/local/bin/sway

Sway will drop root permissions shortly after startup.

Configuration

If you already use i3, then copy your i3 config to ~/.config/sway/config and it'll work out of the box. Otherwise, copy the sample configuration file to ~/.config/sway/config. It is usually located at /etc/sway/config. Run man 5 sway for information on the configuration.

Running

Run sway from a TTY. Some display managers may work but are not supported by sway (gdm is known to work fairly well).