Initial commit

2025-09-14 11:29:21 +02:00
commit d510d777ca
12 changed files with 1246 additions and 0 deletions
--- a/scripts/backtunnel-share
+++ b/scripts/backtunnel-share
@@ -0,0 +1,116 @@
+#!/usr/bin/env bash
+
+# Copyright (c) 2025. LUXIM d.o.o., Slovenia - Matjaž Mozetič.
+
+# backtunnel-share: Share a folder using reverse SSH for a limited duration
+# Syntax: backtunnel-share /path/to/folder with remoteuser:remotehost for 2h
+# Options: -p|--tunnel-port <PORT>  -l|--local-ssh-port <PORT>  -h|--help
+
+set -euo pipefail
+
+TUNNEL_PORT=2222       # remote-side port exposed via -R
+LOCAL_SSH_PORT=22      # local sshd port to forward to
+DURATION=""            # required: e.g. 30m, 2h, 1d
+
+usage() {
+  cat >&2 <<EOF
+Usage:
+  $(basename "$0") /path/to/folder with remoteuser:remotehost for <duration> [options]
+
+Positional (required, in order):
+  /path/to/folder         Informational only (the actual folder is mounted by backtunnel-access)
+  with                    Literal keyword
+  remoteuser:remotehost   Or remoteuser@remotehost
+  for                     Literal keyword
+  <duration>              e.g. 30m, 2h, 1d (passed to 'timeout')
+
+Options:
+  -p, --tunnel-port N       Remote tunnel port (default: ${TUNNEL_PORT})
+  -l, --local-ssh-port N    Local sshd port to expose (default: ${LOCAL_SSH_PORT})
+  -h, --help                Show this help
+
+Examples:
+  $(basename "$0") ~/projects with alice:vps.example.com for 2h
+  $(basename "$0") ~/projects with alice@vps.example.com for 1d -p 4422 -l 2222
+EOF
+  exit 1
+}
+
+# --- basic positional parsing ---
+[[ $# -lt 5 ]] && usage
+
+FOLDER=$1
+KW1=$2
+REMOTE=$3
+KW2=$4
+DURATION=$5
+shift 5 || true
+
+[[ "$KW1" != "with" ]] && usage
+[[ "$KW2" != "for"  ]] && usage
+
+# --- optional flags ---
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    -p|--tunnel-port)
+      [[ $# -lt 2 ]] && usage
+      TUNNEL_PORT=$2
+      shift 2
+      ;;
+    -l|--local-ssh-port)
+      [[ $# -lt 2 ]] && usage
+      LOCAL_SSH_PORT=$2
+      shift 2
+      ;;
+    -h|--help)
+      usage
+      ;;
+    *)
+      echo "Unknown option: $1" >&2
+      usage
+      ;;
+  esac
+done
+
+# --- validate duration (timeout supports s,m,h,d) ---
+if [[ ! "$DURATION" =~ ^[0-9]+[smhd]$ ]]; then
+  echo "Invalid duration '$DURATION' (use forms like 30m, 2h, 1d)." >&2
+  exit 1
+fi
+
+# --- split remote user/host ---
+REMOTE_USER="" REMOTE_HOST=""
+if [[ "$REMOTE" == *:* ]]; then
+  REMOTE_USER=${REMOTE%%:*}
+  REMOTE_HOST=${REMOTE#*:}
+elif [[ "$REMOTE" == *"@"* ]]; then
+  REMOTE_USER=${REMOTE%%@*}
+  REMOTE_HOST=${REMOTE#*@}
+else
+  echo "Invalid remote format. Use remoteuser:remotehost or remoteuser@remotehost" >&2
+  exit 1
+fi
+
+# --- deps check ---
+command -v ssh >/dev/null 2>&1 || { echo "ssh not found."; exit 1; }
+command -v timeout >/dev/null 2>&1 || { echo "timeout not found."; exit 1; }
+
+echo "⏳ Sharing '${FOLDER}' via reverse SSH:"
+echo "    local sshd port     : ${LOCAL_SSH_PORT}"
+echo "    remote bind port    : ${TUNNEL_PORT} (on ${REMOTE_HOST})"
+echo "    remote user         : ${REMOTE_USER}"
+echo "    duration            : ${DURATION}"
+echo
+echo "Tip: On the remote side, mount with:"
+echo "     backtunnel-access '${FOLDER}' from ${REMOTE_USER}@${REMOTE_HOST} -p ${TUNNEL_PORT}"
+
+timeout "$DURATION" ssh -N \
+  -R "${TUNNEL_PORT}:localhost:${LOCAL_SSH_PORT}" \
+  -- "${REMOTE_USER}@${REMOTE_HOST}"
+
+rc=$?
+if [[ $rc -eq 124 ]]; then
+  echo "⏹️  Sharing ended: reached duration (${DURATION})."
+  exit 0
+fi
+exit "$rc"