#!/bin/bash
# Ladill jailed shell for the hosting browser terminal. Per session (private mount
# ns): /home holds only this user's dir, and /etc/passwd|group expose only root +
# this user. The customer can never see other tenants, the host fs, or secrets.
# Usage: ladill-jailsh <username> [relpath]
set -euo pipefail
JAIL=/home/jail
U=${1:-}
REL=${2:-/public_html}
[ -n "$U" ] || { echo 'usage: ladill-jailsh <user> [relpath]'; exit 2; }
UID_=$(id -u "$U" 2>/dev/null || true)
GID_=$(id -g "$U" 2>/dev/null || true)
[ -n "$UID_" ] && [ "$UID_" -ge 1000 ] || { echo 'refusing: not a hosting user'; exit 1; }
HOMEDIR=/home/$U
[ -d "$HOMEDIR" ] || { echo 'no home directory'; exit 1; }
case "$REL" in *..*) REL=/public_html;; esac
if [ -z "${LADILL_JAIL_NS:-}" ]; then
  exec env LADILL_JAIL_NS=1 unshare --mount --propagation private -- "$0" "$U" "$REL"
fi
# /home with only this user's directory
mount -t tmpfs -o mode=0755,nosuid,nodev tmpfs "$JAIL/home"
mkdir -p "$JAIL/home/$U"
mount --bind "$HOMEDIR" "$JAIL/home/$U"
# passwd/group exposing only root + this user (no tenant enumeration)
mount -t tmpfs -o mode=0755,nosuid,nodev tmpfs "$JAIL/run"
{ echo 'root:x:0:0:root:/root:/bin/bash'; getent passwd "$U"; } > "$JAIL/run/passwd"
{ echo 'root:x:0:'; getent group "$U"; } > "$JAIL/run/group"
mount --bind "$JAIL/run/passwd" "$JAIL/etc/passwd"
mount --bind "$JAIL/run/group" "$JAIL/etc/group"
export HOME="/home/$U" USER="$U" LOGNAME="$U" SHELL=/bin/bash PATH=/usr/bin:/bin
export TERM="${TERM:-xterm-256color}" LADILL_START_DIR="/home/$U$REL" HOSTNAME="$(hostname 2>/dev/null || echo ladill)"
exec /usr/sbin/chroot --userspec="$UID_:$GID_" "$JAIL" /bin/bash --rcfile /etc/ladill-jail-bashrc -i