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s6-rc: pre-compute more stuff as nix exprs; don't even run s6-rc-init

This commit is contained in:
Colin 2024-03-26 12:36:46 +00:00
parent 7bb67391ae
commit 55c8a98c33
1 changed files with 30 additions and 37 deletions
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67
modules/users/s6-rc.nix
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@ -249,6 +249,27 @@ let
})
services
;
# create a template s6 "live" dir, which can be copied at runtime in /run/user/{uid}/s6/live.
# this is like a minimal versio of `s6-rc-init`, but tightly coupled to my setup
# wherein the scandir is external and selectively links back to the livedir
mkLiveDir = compiled: pkgs.runCommandLocal "s6-livedir" {} ''
mkdir $out
touch $out/lock
touch $out/prefix # no prefix: empty
mkdir $out/compiled
cp ${compiled}/{db,lock,n,resolve.cdb} $out/compiled
touch $out/state
mkdir $out/servicedirs
mkdir $out/servicedirs/.s6-svscan
for svc in $(ls ${compiled}/servicedirs); do
# s6-rc-init gives each service one byte of state, initialized to zero. i mimic that here:
echo -n '\x00' >> $out/state
mkdir $out/servicedirs/$svc
done
'';
in
{
options.sane.users = with lib; mkOption {
@ -261,7 +282,9 @@ in
compiled = compileServices sources;
uid = config'.users.users."${name}".uid;
scanDir = mkScanDir "/run/user/${builtins.toString uid}/s6/live" compiled;
liveDir = mkLiveDir compiled;
in {
fs.".config/s6/live".symlink.target = liveDir;
fs.".config/s6/scandir".symlink.target = scanDir;
fs.".config/s6/compiled".symlink.target = compiled;
# exposed only for convenience
@ -269,42 +292,13 @@ in
fs.".profile".symlink.text = ''
function initS6Dirs() {
local S6_RUN_DIR="$XDG_RUNTIME_DIR/s6"
local COMPILED="$S6_RUN_DIR/compiled"
local LIVE="$S6_RUN_DIR/live"
local SCANDIR="$S6_RUN_DIR/scandir"
local LIVE="$XDG_RUNTIME_DIR/s6/live"
rm -rf "$COMPILED" "$LIVE" "$SCANDIR"
mkdir -p "$SCANDIR"
s6-svscan "$SCANDIR" &
local SVSCAN=$!
# the scandir is just links back into the compiled dir,
# so the compiled dir therefore needs to be writable:
rm -rf "$COMPILED"
cp --dereference -R "$HOME/.config/s6/compiled" "$COMPILED"
chmod -R 0700 "$COMPILED"
s6-rc-init -c "$COMPILED" -l "$LIVE" "$SCANDIR"
# kill the svscan process:
s6-svscanctl -tb "$SCANDIR"
wait "$SVSCAN"
# cleanup the servicedirs: remove files which s6-svscan will want to create for itself.
rm "$LIVE/servicedirs"/*/supervise/{control,death_tally,lock,status}
rmdir "$LIVE/servicedirs"/*/{event,supervise}
# remove files which just aren't needed (because they live in the s6-svscan dir instead)
rm "$LIVE/servicedirs"/*/{run,run.user,finish,finish.user,notification-fd}
rm -rf "$LIVE/servicedirs"/*/data
# ^ so wait, after this every live/servicedirs/FOO directory is literally just an empty directory.
# i can *surely* simplify all of this; maybe not even invoke s6-rc-init here at *all*.
mkdir "$LIVE/servicedirs/.s6-svscan"
# remove unnecessary, duplicated dirs
rm -rf "$SCANDIR"
rm -rf "$COMPILED/servicedirs"
rm "$LIVE/scandir"
mkdir -p "$LIVE" # create parent dirs
rm -rf "$LIVE" # remove old state
# the live dir needs to be read+write. initialize it via the template in ~/.config/s6:
cp --dereference -R "$HOME/.config/s6/live" "$LIVE"
chmod -R 0700 "$LIVE"
# ensure the log dir, since that'll be needed by every service.
# the log dir should already exist by now (nixos persistence); create it just in case something went wrong.
@ -313,8 +307,7 @@ in
function startS6() {
local S6_TARGET="''${1-default}"
local S6_RUN_DIR="$XDG_RUNTIME_DIR/s6"
local LIVE="$S6_RUN_DIR/live"
local LIVE="$XDG_RUNTIME_DIR/s6/live"
test -e "$LIVE" || initS6Dirs