From 0dbd8a01ffeb432ad12dfc549b495716e82286f3 Mon Sep 17 00:00:00 2001
From: ed <s@ocv.me>
Date: Mon, 9 Aug 2021 22:12:39 +0200
Subject: [PATCH] mount PWD into chroot for config files

---
 bin/prisonparty.sh | 100 ++++++++++++++++++++++++++++-----------------
 1 file changed, 63 insertions(+), 37 deletions(-)

diff --git a/bin/prisonparty.sh b/bin/prisonparty.sh
index e3562b6f..55b7728d 100755
--- a/bin/prisonparty.sh
+++ b/bin/prisonparty.sh
@@ -1,40 +1,59 @@
 #!/bin/bash
 set -e
 
-# runs copyparty in a chroot
+# runs copyparty (or any other python script really) in a chroot
 #
-# assumption: all items within the following directories are owned by root
+# assumption: these directories, and everything within, are owned by root
 sysdirs=(bin lib lib32 lib64 sbin usr)
 
 
-# read arguments
-{
-	jail="$1"; shift
-	uid="$1"; shift
-	gid="$1"; shift
-	
-	vols=()
-	while true; do
-		v="$1"; shift
-		[ "$v" = -- ] && break  # end of volumes
-		[ "$#" -eq 0 ] && break  # invalid usage
-		vols+=("$v")
-	done
-	cpp="$1"; shift
-} || {
-	echo "usage: ./prisonparty.sh <ROOTDIR> <UID> <GID> [VOLDIR [VOLDIR...]] -- copyparty-sfx.py [...]"
-	echo "example: ./prisonparty.sh /var/jail 1000 1000 /mnt/nas/music -- copyparty-sfx.py -v /mnt/nas/music::rwmd"
-	exit 1
+# error-handler
+help() { cat <<'EOF'
+
+usage:
+  ./prisonparty.sh <ROOTDIR> <UID> <GID> [VOLDIR [VOLDIR...]] -- copyparty-sfx.py [...]"
+
+example:
+  ./prisonparty.sh /var/jail 1000 1000 /mnt/nas/music -- copyparty-sfx.py -v /mnt/nas/music::rwmd"
+
+EOF
+exit 1
 }
 
 
-# debug/vis
-echo "chroot-dir: [$jail]"
-echo "user:group: [$uid:$gid]"
-echo " copyparty: [$cpp]"
-for v in "${vols[@]}"; do
-	echo "     mount: [$v]"
+# read arguments
+trap help EXIT
+jail="$1"; shift
+uid="$1"; shift
+gid="$1"; shift
+
+vols=()
+while true; do
+	v="$1"; shift
+	[ "$v" = -- ] && break  # end of volumes
+	[ "$#" -eq 0 ] && break  # invalid usage
+	vols+=("$v")
 done
+cpp="$1"; shift
+cpp="$(realpath "$cpp")"
+cppdir="$(dirname "$cpp")"
+trap - EXIT
+
+
+# debug/vis
+echo
+echo "chroot-dir = $jail"
+echo "user:group = $uid:$gid"
+echo " copyparty = $cpp"
+echo
+printf '\033[33m%s\033[0m\n' "copyparty can access these folders and all their subdirectories:"
+for v in "${vols[@]}"; do
+	printf '\033[36m ├─\033[0m %s \033[36m ── added by (You)\033[0m\n' "$v"
+done
+printf '\033[36m ├─\033[0m %s \033[36m ── where the copyparty binary is\033[0m\n' "$cppdir"
+printf '\033[36m ╰─\033[0m %s \033[36m ── the folder you are currently in\033[0m\n' "$PWD"
+vols+=("$cppdir" "$PWD")
+echo
 
 
 # resolve and remove trailing slash
@@ -43,10 +62,15 @@ jail="${jail%/}"
 
 
 # bind-mount system directories and volumes
-for v in "${sysdirs[@]}" "${vols[@]}"; do
-  mkdir -p "$jail/$v"
-  mount | grep -qF " on $jail/$v " ||
-    mount --bind /$v "$jail/$v"
+printf '%s\n' "${sysdirs[@]}" "${vols[@]}" | LC_ALL=C sort |
+while IFS= read -r v; do
+	[ -e "/$v" ] || {
+		# printf '\033[1;31mfolder does not exist:\033[0m %s\n' "$v"
+		continue
+	}
+	mkdir -p "$jail/$v"
+	mount | grep -qF " on $jail/$v " ||
+		mount --bind /$v "$jail/$v"
 done
 
 
@@ -55,14 +79,16 @@ mkdir -p "$jail/tmp"
 chown -R "$uid:$gid" "$jail/tmp"
 
 
-# copy sfx into jail
-cp -pv "$cpp" "$jail/copyparty.py"
-
-
 # run copyparty
-/sbin/chroot --userspec=$uid:$gid "$jail" "$(which python3)" /copyparty.py "$@"
+/sbin/chroot --userspec=$uid:$gid "$jail" "$(which python3)" "$cpp" "$@" && rv=0 || rv=$?
 
 
 # cleanup if not in use
-lsof "$jail" | grep -qF "$jail" ||
-mount | grep -F " on $jail" | awk '{sub(/ type .*/,"");sub(/.* on /,"");print}' | LC_ALL=C sort -r  | tr '\n' '\0' | xargs -r0 umount
+lsof "$jail" | grep -qF "$jail" &&
+	echo "chroot is in use, will not cleanup" ||
+{
+	mount | grep -F " on $jail" |
+	awk '{sub(/ type .*/,"");sub(/.* on /,"");print}' |
+	LC_ALL=C sort -r  | tr '\n' '\0' | xargs -r0 umount
+}
+exit $rv