nitro@: simplify socket directory handling, run in new process group

Now instead of worrying about SOCKET_PREFIX and SOCKDIR and so on, you
just set NITRO_SOCK to where you want it to be. It does need to be in
a nitro-specific directory for notify things, but you shouldn't
overwriting this most of the time anyway.

As for the process group, given the main usage (user services), this
seems perfectly reasonable.

3 files changed, 10 insertions, 11 deletions

diff --git a/nitro@/README.md b/nitro@/README.md
index bf94a96..d042053 100644
--- a/nitro@/README.md
+++ b/nitro@/README.md
@@ -13,14 +13,12 @@ Here are the settings you can set / may want to set:
   example. It is also exported, so they may be affected by this.
 * `$CONFDIR`: the nitro config dirctory for the user (equivalent of
   /etc/nitro). Defaults to `$HOME/.config/nitro`.
-* `$SOCKET_PREFIX`: where to place the user's runtime directory, if
-  any. Basically the `/run/user` prefix for default `$SOCKDIR`. Note that this
-  is sensitive! `unitroctl` won't know if you change this, so changing this (or
-  `$SOCKDIR`) will require that the user manually set `$NITRO_SOCK`.
-* `$SOCKDIR`: the parent directory for nitro's runtime directory. For example,
-  if `$NITRO_SOCK` will be `/foo/bar/nitro/nitro.sock`, then this is
-  `/foo/bar`. `$NITRO_SOCK` is not configurable (though you can always edit it
-  in!). Defaults to `${SOCKET_PREFIX:-/run/user}/$UID`.
+* `$NITRO_SOCK`: where to place nitro's socket. Be very careful
+  setting this. Defaults to `/run/user/$UID/nitro/nitro.sock`, and
+  this is what `unitroctl` uses as well. The setup script will ensure
+  that the parent's parent directory (in this case `/run/user/$UID`
+  exists, if not creating it belonging to the user with 0700
+  permissions (as per `XDG_RUNTIME_DIR`).
 * `$CHPSTUSER`: what to pass to chpst's `-u` argument. Defaults to `:$(id -u
   $USER):$(id -G $USER)`, so for UID 1000 GID 1000 supplementary groups 1, 2, 3,
   this will be `:1000:1000:1:2:3`. Importantly, this is not sanity-checked, so
diff --git a/nitro@/common b/nitro@/common
index bd0e300..8ebe3aa 100644
--- a/nitro@/common
+++ b/nitro@/common
@@ -11,6 +11,7 @@ GID=$(id -g "$USER")
 : ${HOME:=$(getent passwd "$USER" | cut -d: -f6)} \
   ${CONFDIR:="$HOME"/.config/nitro} \
   ${CHPSTUSER:=:$UID:$(id -G "$USER" | tr ' ' ':')} \
-  ${SOCKDIR:=${SOCKET_PREFIX:-/run/user}/$UID}
+  ${NITRO_SOCK:=/run/user/$UID/nitro/nitro.sock}
 
-export USER HOME NITRO_SOCK="$SOCKDIR"/nitro/nitro.sock
+SOCKDIR=$(dirname "$(dirname "$NITRO_SOCK")")
+export USER HOME NITRO_SOCK
diff --git a/nitro@/run b/nitro@/run
index d368468..09526ce 100755
--- a/nitro@/run
+++ b/nitro@/run
@@ -4,4 +4,4 @@
 USER="$1"
 . ./common
 
-exec chpst -u "$CHPSTUSER" nitro "$CONFDIR"
+exec chpst -P -u "$CHPSTUSER" nitro "$CONFDIR"