X: Improve lockscreen handling

Added lockscreen trapping and media pausing for lockscreen.
When it is invoked `lockscreen`, all media will be attempted to be pause
and the system will be muted.
Then the lockscreen is engaged.
This should happen automatically when the screen shuts off or the system
suspends or hibernates and can be invoked manually, as before, with
super+x shortcut.

X/.config/xresources/xinitrc

@@ -72,4 +72,6 @@ setxkbmap -option grp:alt_shift_toggle
 # set a timeout of 500ms, if pressed longer it will ignore esc
 type xcape >/dev/null 2>&1 && xcape -e 'Control_L=Escape' -t 500
 
+type feh >/dev/null 2>&1 && exec feh --bg-scale ~/media/pictures/wall.jpg &
+type xss-lock >/dev/null 2>&1 && exec xss-lock &
 type i3 >/dev/null 2>&1 && exec i3

bootstrap/packages.txt

@@ -220,6 +220,7 @@ xclip
 xorg-xev
 xorg-xinit
 xorg-xinput
+xss-lock
 youtube-dl
 zathura-pdf-mupdf
 zsh-autosuggestions

i3/.config/i3/config

@@ -180,12 +180,6 @@ bindsym $mod+F12 reload
 # restart i3 inplace (preserves your layout/session, can be used to upgrade i3)
 bindsym $mod+Shift+F12 restart
 
-# set a pretty wallpaper
-exec_always --no-startup-id feh --bg-scale ~/media/pictures/wall.jpg
-
-# launch polybar (script ensures only 1 instance existing at a time)
-exec_always --no-startup-id polybar-launch top
-
 # default workspaces for most used apps
 # assign [class="^qutebrowser$"] → number 1
 # spotify needs for_window, see https://i3wm.org/docs/userguide.html#assign_workspace
@@ -205,3 +199,7 @@ for_window [class="scratchpad"] move scratchpad
 bindsym $mod+m exec i3-input -F 'mark %s' -l 1 -P 'Mark: '
 # read 1 character and go to the window with the character
 bindsym $mod+apostrophe exec i3-input -F '[con_mark="%s"] focus' -l 1 -P 'Goto: '
+
+# launch polybar (script ensures only 1 instance existing at a time)
+exec_always --no-startup-id polybar-launch top
+

scripts/.local/bin/lockscreen

@@ -1,8 +1,54 @@
 #!/usr/bin/env sh
 
-# In case we want to pause any players
-# (see https://github.com/LukeSmithxyz/voidrice/blob/archi3/.config/sxhkd/sxhkdrc for that)
-# mpc -q pause
-# amixer set Master mute
+# Example locker script -- demonstrates how to use the --transfer-sleep-lock
+# option with i3lock's forking mode to delay sleep until the screen is locked.
 
-i3lock -e -f -c 1d2021
+## CONFIGURATION ##############################################################
+
+# Options to pass to i3lock
+i3lock_options="-e -f -c 1d2021"
+
+# Run before starting the locker
+pre_lock() {
+    # pause all currently playing media and mute system
+    type mpc >/dev/null 2>&1 && mpc -q pause
+    type playerctl >/dev/null 2>&1 && playerctl -s pause
+    type amixer >/dev/null 2>&1 && amixer -q set Master mute
+    return
+}
+
+# Run after the locker exits
+post_lock() {
+    return
+}
+
+###############################################################################
+
+pre_lock
+
+# We set a trap to kill the locker if we get killed, then start the locker and
+# wait for it to exit. The waiting is not that straightforward when the locker
+# forks, so we use this polling only if we have a sleep lock to deal with.
+if [ -e /dev/fd/${XSS_SLEEP_LOCK_FD:--1} ]; then
+    kill_i3lock() {
+        pkill -xu $EUID "$@" i3lock
+    }
+
+    trap kill_i3lock TERM INT
+
+    # we have to make sure the locker does not inherit a copy of the lock fd
+    i3lock $i3lock_options {XSS_SLEEP_LOCK_FD}<&-
+
+    # now close our fd (only remaining copy) to indicate we're ready to sleep
+    exec {XSS_SLEEP_LOCK_FD}<&-
+
+    while kill_i3lock -0; do
+        sleep 0.5
+    done
+else
+    trap 'kill %%' TERM INT
+    i3lock -n $i3lock_options &
+    wait
+fi
+
+post_lock