feb0e1c74d
Fixes #2425. wlroots can only handle one outgoing transfer at a time, so it keeps a list of pending selections. The head of the list is the currently-active selection, and when that transfer completes and is destroyed, the next one is started. The trouble is when you have a transfer to some app that is misbehaving. fcitx is one such application. With really large transfers, fcitx will hang and never wake up again. So, you can end up with a transfer list that looks like this: | T1: started | T2: pending | T3: pending | T4: pending | The file descriptor for transfer T1 is registered in libwayland's epoll loop. The rest are waiting in wlroots' list. As a user, you want your clipboard back, so you `pkill fcitx`. Now Xwayland sends `XCB_DESTROY_NOTIFY` to let us know to give up. We clean up T4 first. Due to a bug in wlroots code, we register the (fd, transfer data pointer) pair for T1 with libwayland *again*, despite it already being registered. We do this 2 more times as we remove T3 and T2. Finally, we remove T1 and `free` all the memory associated with it, before `close`-ing its transfer file descriptor. However, we still have 3 copies of T1's file descriptor left in the epoll loop, since we erroneously added them as part of removing T2/3/4. When we `close` the file descriptor as part of T1's teardown, we actually cause the epoll loop to wake up the next time around, saying "this file descriptor has activity!" (it was closed, so `read`-ing would normally return 0 to let us know of EOF). But instead of returning 0, it returns -1 with `EBADF`, because the file descriptor has already been closed. And finally, as part of error-handling this, we access the transfer pointer, which was `free`'d. And we crash. |
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| .builds | ||
| backend | ||
| contrib | ||
| docs | ||
| examples | ||
| include | ||
| protocol | ||
| render | ||
| tinywl | ||
| types | ||
| util | ||
| xcursor | ||
| xwayland | ||
| .editorconfig | ||
| .gitignore | ||
| CONTRIBUTING.md | ||
| LICENSE | ||
| README.md | ||
| meson.build | ||
| meson_options.txt | ||
| wlroots.syms | ||
README.md
wlroots
Pluggable, composable, unopinionated modules for building a Wayland compositor; or about 50,000 lines of code you were going to write anyway.
- wlroots provides backends that abstract the underlying display and input hardware, including KMS/DRM, libinput, Wayland, X11, and headless backends, plus any custom backends you choose to write, which can all be created or destroyed at runtime and used in concert with each other.
- wlroots provides unopinionated, mostly standalone implementations of many Wayland interfaces, both from wayland.xml and various protocol extensions. We also promote the standardization of portable extensions across many compositors.
- wlroots provides several powerful, standalone, and optional tools that implement components common to many compositors, such as the arrangement of outputs in physical space.
- wlroots provides an Xwayland abstraction that allows you to have excellent Xwayland support without worrying about writing your own X11 window manager on top of writing your compositor.
- wlroots provides a renderer abstraction that simple compositors can use to avoid writing GL code directly, but which steps out of the way when your needs demand custom rendering code.
wlroots implements a huge variety of Wayland compositor features and implements them right, so you can focus on the features that make your compositor unique. By using wlroots, you get high performance, excellent hardware compatibility, broad support for many wayland interfaces, and comfortable development tools - or any subset of these features you like, because all of them work independently of one another and freely compose with anything you want to implement yourself.
Check out our wiki to get started with wlroots.
wlroots is developed under the direction of the sway project. A variety of wrapper libraries are available for using it with your favorite programming language.
Building
Install dependencies:
- meson
- wayland
- wayland-protocols
- EGL
- GLESv2
- libdrm
- GBM
- libinput
- xkbcommon
- udev
- pixman
- systemd (optional, for logind support)
- elogind (optional, for logind support on systems without systemd)
If you choose to enable X11 support:
- xcb
- xcb-composite
- xcb-xfixes
- xcb-xinput
- xcb-image
- xcb-render
- x11-xcb
- xcb-errors (optional, for improved error reporting)
- x11-icccm (optional, for improved Xwayland introspection)
Run these commands:
meson build
ninja -C build
Install like so:
sudo ninja -C build install
Contributing
See CONTRIBUTING.md.