bspwm

hardened fork of baskerville/bspwm. security fixes, memory safety improvements, reduced X11 latency.

overview

binary tree tiling window manager. socket IPC with bspc client. requires sxhkd for keybindings.

changes from upstream

security hardening

• buffer overflow fixes with bounds checking
• integer overflow protection on size calculations
• safe memory allocation wrappers (NULL checks, overflow detection)
• format string vulnerability fixes
• input validation on all IPC commands
• resource limits (tree depth, string sizes)

memory safety

• scratch arena allocator for per-command temporary allocations
• eliminates leak-prone manual free() on error paths
• __attribute__((cold)) on error handlers for better I-cache utilization
• struct field reordering to eliminate padding holes

X11 pipelining

reduced X11 round-trips in rule application (6→1) and client initialization (4→1). benefit depends on X11 latency:

• localhost: ~10μs per round-trip, pipelining saves ~50μs (not measurable)
• remote X11: ~500μs per round-trip, pipelining saves ~2-4ms per window

benchmark results (localhost, 100 iterations)

                      upstream    current
command latency:         4 μs       4 μs
window create+map:    1634 μs    1637 μs

identical performance. security hardening adds no measurable overhead.

benchmarking

actual X11 latency comparison (requires Xvfb):

cd benches
./compare_latency.sh [iterations]

measures real IPC round-trip and window creation latency. this is what matters.

CPU cycle microbenchmarks exist in benches/microbench.c but are UX-irrelevant. 4000 cycles = 1.3μs. one X11 round-trip = 500μs.

build

make                  # X11 backend -> bspwm
make install          # installs bspwm, bspc and the xsessions entry

make BACKEND=wlroots           # Wayland compositor -> bspwm-wl, against the distro wlroots (pkg-config wlroots-0.20)
make BACKEND=wlroots install   # installs bspwm-wl, bspc and the wayland-sessions entry
make BACKEND=wlroots WLROOTS_DIR=../wlroots WLROOTS_ABI=0.21   # or against a wlroots source checkout

each backend is a separate build and a separate binary. objects go under build/<backend>/, so the two can be built and installed side by side. bspc is shared and links no display library. the wayland build has no sxhkd: keybindings are handled in-process via bspc keybind. bars: waybar with ext/workspaces for desktops and wlr/taskbar for windows. a compositor restart (bspc wm -r) closes every client, as on any Wayland compositor. github releases and the aur package build the X11 backend only.

dependencies (x11): libxcb, xcb-util, xcb-util-keysyms, xcb-util-wm, libxkbcommon dependencies (wlroots): wlroots 0.20, wayland, wayland-protocols, wlr-protocols, libxkbcommon, pixman, libdrm, xorg-xwayland

arch packages: pkg/arch/PKGBUILD (bspwm1, X11) and pkg/arch/bspwm1-wl/PKGBUILD (bspwm1-wl, Wayland)

binary size: 285KB (+34KB / +13% vs upstream 0.9.12)

configuration

config: $XDG_CONFIG_HOME/bspwm/bspwmrc keybindings: sxhkd examples: examples/

license

BSD-2-Clause