Enhance backtunnel-share with improved desktop integration, port collision checks, and pre-flight validations

completions/backtunnel.bash

@@ -32,6 +32,20 @@ _backtunnel_complete() {
     return 0
   fi
 
+  # backtunnel-share: after positionals, propose flags incl. invite
+  if [[ ${COMP_WORDS[0]} == backtunnel-share && ${COMP_CWORD} -ge 5 ]]; then
+    local opts="-p --tunnel-port -l --local-ssh-port -i --invite --invite-mount --invite-file --qr -h --help"
+    mapfile -t COMPREPLY < <(compgen -W "${opts}" -- "${cur}")
+    return 0
+  fi
+
+  # backtunnel-access: after positionals, propose its flags
+  if [[ ${COMP_WORDS[0]} == backtunnel-access && ${COMP_CWORD} -ge 3 ]]; then
+    local opts="-p --port -m --mount-point -h --help"
+    mapfile -t COMPREPLY < <(compgen -W "${opts}" -- "${cur}")
+    return 0
+  fi
+
   COMPREPLY=()
 }
 

desktop/backtunnel.desktop

@@ -2,7 +2,18 @@
 Type=Application
 Name=BackTunnel
 Comment=Reverse SSH folder sharing and access
-Exec=backtunnel-share %f
+Exec=bash -lc '
+  FOLDER="%f";
+  REMOTE="$(kdialog --inputbox "Remote (user@host or user:host):" "user@vps.example.com")" || exit 1;
+  DUR="$(kdialog --combobox "Share duration" 30m 2h 6h 1d 2d --editable "2h")" || exit 1;
+  TPORT="$(kdialog --inputbox "Tunnel port on remote:" "2222")" || exit 1;
+  LPORT="$(kdialog --inputbox "Local SSH port to expose:" "22")" || exit 1;
+  if kdialog --yesno "Print invite line for chat?"; then INV="-i"; else INV=""; fi;
+  if kdialog --yesno "Show QR code for the invite?"; then QR="--qr"; else QR=""; fi;
+  MP="$(kdialog --inputbox "Suggested mount point in invite:" "/mnt/remote-rssh")" || exit 1;
+  konsole --noclose -e backtunnel-share "$FOLDER" with "$REMOTE" for "$DUR" \
+    -p "$TPORT" -l "$LPORT" $INV $QR --invite-mount "$MP"
+'
 Icon=network-vpn
 Terminal=true
 Categories=Network;Utility;

man/backtunnel.1

@@ -18,7 +18,8 @@ The sharing ends automatically after the given \fIduration\fR via \fBtimeout\fR.
 With the \fB--invite\fR option, \fBbacktunnel-share\fR prints a ready-to-copy access command for the remote user,
 which can be pasted directly into a chat or terminal. The invite can also be rendered as a QR code or written to a file.
 
-\fBbacktunnel-access\fR mounts the shared folder from the remote side using \fBsshfs\fR by connecting to \fBlocalhost:<port>\fR on the remote host (the port exposed by \fBbacktunnel-share\fR).
+\fBbacktunnel-access\fR mounts the shared folder from the remote side using \fBsshfs\fR by connecting to \fBlocalhost:<port>\fR on the remote host
+(the port exposed by \fBbacktunnel-share\fR).
 
 .SH OPTIONS
 .SS backtunnel-share options
@@ -80,7 +81,7 @@ Share for 1 day, using custom ports:
 /home/user/docs with alice:vps.example.com for 1d -p 4422 -l 2222
 
 .TP
-Share with invite printed:
+Share for 2 hours and print an invite:
 .B backtunnel-share
 /home/user/docs with alice@vps.example.com for 2h -i
 

scripts/backtunnel-share

@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 
 # Copyright (c) 2025. LUXIM d.o.o., Slovenia - Matjaž Mozetič.
+# Licensed under the GNU GPL v3.0
 
 # backtunnel-share: Share a folder using reverse SSH for a limited duration
 # Syntax: backtunnel-share /path/to/folder with remoteuser:remotehost for 2h
@@ -163,8 +164,23 @@ fi
 
 echo "Tip: On the remote side, mount with:"
 echo "     backtunnel-access '${FOLDER}' from ${REMOTE_USER}@${REMOTE_HOST} -p ${TUNNEL_PORT}"
+echo "To stop sharing early: press Ctrl+C here."
 
+# --- optional pre-flight: warn if remote loopback port is already in use (best-effort) ---
+if ssh -o BatchMode=yes -o ConnectTimeout=5 "${REMOTE_USER}@${REMOTE_HOST}" \
+     "command -v nc >/dev/null 2>&1 && nc -z 127.0.0.1 ${TUNNEL_PORT}"; then
+  echo "⚠️  Port ${TUNNEL_PORT} on remote 127.0.0.1 appears in use; choose another with -p." >&2
+  # Uncomment the next line to make it a hard failure:
+  # exit 1
+fi
+
+# Bind reverse to 127.0.0.1 on the REMOTE host (private-by-default).
+# Keepalive so the tunnel drops on dead links.
+# Exit fast if the reverse bind fails (e.g., port in use).
 timeout "$DURATION" ssh -N \
+  -o ExitOnForwardFailure=yes \
+  -o ServerAliveInterval=15 \
+  -o ServerAliveCountMax=3 \
   -R "${TUNNEL_PORT}:localhost:${LOCAL_SSH_PORT}" \
   -- "${REMOTE_USER}@${REMOTE_HOST}"
 

scripts/install.sh

@@ -44,4 +44,12 @@ if [[ -d /usr/share/applications ]]; then
   sudo install -m 0644 desktop/backtunnel.desktop /usr/share/applications/backtunnel.desktop || true
 fi
 
+# Refresh desktop DB and KDE service cache (best-effort)
+command -v update-desktop-database >/dev/null 2>&1 && sudo update-desktop-database -q || true
+if command -v kbuildsycoca6 >/dev/null 2>&1; then
+  kbuildsycoca6 --noincremental >/dev/null 2>&1 || true
+elif command -v kbuildsycoca5 >/dev/null 2>&1; then
+  kbuildsycoca5 --noincremental >/dev/null 2>&1 || true
+fi
+
 echo "✅ BackTunnel installed. You may need to restart your shell and Dolphin."

scripts/uninstall.sh

@@ -39,4 +39,12 @@ sudo rm -f /usr/share/kservices5/ServiceMenus/backtunnel_access.desktop || true
 echo "🧹 Removing desktop launcher ..."
 sudo rm -f /usr/share/applications/backtunnel.desktop || true
 
+# Refresh desktop DB and KDE service cache (best-effort)
+command -v update-desktop-database >/dev/null 2>&1 && sudo update-desktop-database -q || true
+if command -v kbuildsycoca6 >/dev/null 2>&1; then
+  kbuildsycoca6 --noincremental >/dev/null 2>&1 || true
+elif command -v kbuildsycoca5 >/dev/null 2>&1; then
+  kbuildsycoca5 --noincremental >/dev/null 2>&1 || true
+fi
+
 echo "✅ Uninstall complete."