From: Thomas Walker Lynch <eknp9n@reasoningtechnology.com>
Date: Thu, 25 Sep 2025 13:37:21 +0000 (+0000)
Subject: yet aother
X-Git-Url: https://git.reasoningtechnology.com/style/static/git-favicon.png?a=commitdiff_plain;h=a6a9bf2cd197fc6f6fb4f9ef3efb142d1749896b;p=subu

yet aother
---

diff --git a/developer/source/mount/masu_subu__map_own.sh b/developer/source/mount/masu_subu__map_own.sh
index aa2c3a5..c880a54 100755
--- a/developer/source/mount/masu_subu__map_own.sh
+++ b/developer/source/mount/masu_subu__map_own.sh
@@ -3,46 +3,52 @@
 set -euo pipefail
 
 need(){ command -v "$1" >/dev/null 2>&1 || { echo "missing: $1" >&2; exit 1; }; }
+need bindfs; need findmnt; need umount
 
 masu="${1:?usage: $0 <masu> <subu> [--suid] }"
 subu="${2:?usage: $0 <masu> <subu> [--suid] }"
 want_suid=0
-case "${3-}" in
-  --suid) want_suid=1 ;;
-  "" ) ;;
-  * ) echo "unknown option: $3" >&2; exit 2 ;;
-esac
+[[ "${3-}" == "--suid" ]] && want_suid=1
 
-need bindfs; need findmnt; need mountpoint; id "$masu" >/dev/null; id "${masu}-${subu}" >/dev/null
+master_user="$masu"
+master_group="$masu"
+subu_user="${masu}-${subu}"
+subu_group="${masu}-${subu}"
+
+id "$master_user" >/dev/null
+id "$subu_user"   >/dev/null
 
 src="/home/$masu/subu_data/$subu"
 tgt="/home/$masu/subu/$subu"
-
-[[ -d "$src" ]] || { echo "Error: source dir '$src' does not exist" >&2; exit 1; }
+[[ -d "$src" ]] || { echo "no source dir: $src" >&2; exit 1; }
 mkdir -p "$tgt"
 
-base_opts="allow_other,default_permissions,exec"
-desired_opts="$base_opts,$([[ $want_suid -eq 1 ]] && echo suid || echo nosuid)"
-map_opt="--map=${masu}-${subu}/${masu}:@${masu}-${subu}/@${masu}"
+# IMPORTANT: don’t stay inside the target tree while (un)mounting
+cd /
 
-# Peel any existing stack at $tgt (no matter what it is)
-while mountpoint -q "$tgt"; do
-  umount "$tgt" 2>/dev/null || umount -l "$tgt" || break
-done
+base_opts="allow_other,default_permissions,exec"
+opts="$base_opts,nosuid"
+(( want_suid )) && opts="$base_opts,suid"
 
-echo "mounting $src -> $tgt  (opts: $desired_opts)"
-bindfs -o "$desired_opts" $map_opt "$src" "$tgt"
+map_opt="--map=${subu_user}/${master_user}:@${subu_group}/@${master_group}"
 
-# If, for any reason, multiple identical layers ended up stacked, peel until one remains.
-while [ "$(findmnt -nr -T "$tgt" | wc -l)" -gt 1 ]; do
-  umount "$tgt" || umount -l "$tgt" || break
+# Peel any existing mount at tgt (use -T to match covering mount)
+while findmnt -nr -T "$tgt" >/dev/null 2>&1; do
+  umount "$tgt" 2>/dev/null || umount -l "$tgt" || break
 done
 
-# Show only the bindfs line (or the only remaining one)
-findmnt -nr -T "$tgt" -o TARGET,SOURCE,FSTYPE,OPTIONS | head -n1
-echo "OK"
-if (( want_suid )); then
-  echo "note: suid enabled; setuid binaries can take effect on this mount."
+echo "mounting $src -> $tgt  (opts: $opts)"
+bindfs -o "$opts" $map_opt "$src" "$tgt"
+
+# Verify
+if findmnt -nr -T "$tgt" -o TARGET,SOURCE,FSTYPE,OPTIONS; then
+  echo "OK"
+  if (( want_suid )); then
+    echo "note: suid is ENABLED at $tgt"
+  else
+    echo "note: nosuid (default) — setuid will NOT take effect at $tgt"
+  fi
 else
-  echo "note: nosuid (default) — setuid will NOT take effect on this mount."
+  echo "❌ bindfs did not mount at $tgt" >&2
+  exit 2
 fi