fix(docker): make x-ui CLI menu work inside containers

check_status() only recognized a systemd service or Alpine's
/etc/init.d/x-ui, neither of which exists in a container where the panel
runs as the foreground main process (PID 1 via "exec /app/x-ui"). Every
CLI command therefore failed with "Please install the panel first", and
restart/restart-xray relied on rc-service/systemctl that aren't present.

Detect the container (/.dockerenv or XUI_IN_DOCKER) and, when inside one:
- resolve the panel binary under /app instead of /usr/local/x-ui
- derive status from the running process instead of a service file
- restart via SIGHUP and restart-xray via SIGUSR1 to the panel process
- show Docker-appropriate guidance for start/stop/enable/disable

The Dockerfile sets XUI_IN_DOCKER/XUI_MAIN_FOLDER so detection is
explicit even though /.dockerenv alone suffices.

Closes #4817

Dockerfile

@@ -63,9 +63,9 @@ RUN chmod +x \
   /app/x-ui \
   /usr/bin/x-ui
 
+ENV XUI_IN_DOCKER="true"
+ENV XUI_MAIN_FOLDER="/app"
 ENV XUI_ENABLE_FAIL2BAN="true"
-# Database backend: set XUI_DB_TYPE=postgres and XUI_DB_DSN=postgres://... to use PostgreSQL.
-# Default (unset) is SQLite stored under /etc/x-ui.
 ENV XUI_DB_TYPE=""
 ENV XUI_DB_DSN=""
 EXPOSE 2053

x-ui.sh

@@ -69,8 +69,17 @@ echo "The OS release is: $release"
 os_version=""
 os_version=$(grep "^VERSION_ID" /etc/os-release | cut -d '=' -f2 | tr -d '"' | tr -d '.')
 
+running_in_docker="false"
+if [[ -f /.dockerenv ]] || [[ "${XUI_IN_DOCKER}" == "true" ]]; then
+    running_in_docker="true"
+fi
+
 # Declare Variables
-xui_folder="${XUI_MAIN_FOLDER:=/usr/local/x-ui}"
+if [[ "${running_in_docker}" == "true" ]]; then
+    xui_folder="${XUI_MAIN_FOLDER:=/app}"
+else
+    xui_folder="${XUI_MAIN_FOLDER:=/usr/local/x-ui}"
+fi
 xui_service="${XUI_SERVICE:=/etc/systemd/system}"
 log_folder="${XUI_LOG_FOLDER:=/var/log/x-ui}"
 mkdir -p "${log_folder}"
@@ -400,6 +409,15 @@ start() {
         echo ""
         LOGI "Panel is running, No need to start again, If you need to restart, please select restart"
     else
+        if [[ "${running_in_docker}" == "true" ]]; then
+            LOGE "Panel process is not running inside this container."
+            LOGI "In Docker the panel is the container's main process. Restart the container to bring it back up:"
+            LOGI "  docker restart <container_name>"
+            if [[ $# == 0 ]]; then
+                before_show_menu
+            fi
+            return 0
+        fi
         if [[ $release == "alpine" ]]; then
             rc-service x-ui start
         else
@@ -425,6 +443,15 @@ stop() {
         echo ""
         LOGI "Panel stopped, No need to stop again!"
     else
+        if [[ "${running_in_docker}" == "true" ]]; then
+            LOGI "In Docker the panel runs as the container's main process."
+            LOGI "To stop it, stop the container from the host:"
+            LOGI "  docker stop <container_name>"
+            if [[ $# == 0 ]]; then
+                before_show_menu
+            fi
+            return 0
+        fi
         if [[ $release == "alpine" ]]; then
             rc-service x-ui stop
         else
@@ -445,6 +472,26 @@ stop() {
 }
 
 restart() {
+    if [[ "${running_in_docker}" == "true" ]]; then
+        if signal_xui HUP; then
+            sleep 1
+            signal_xui USR1
+            LOGI "Restart signal sent to the panel and xray-core."
+        else
+            LOGE "Could not find the running panel process to signal."
+        fi
+        sleep 2
+        check_status
+        if [[ $? == 0 ]]; then
+            LOGI "x-ui and xray Restarted successfully"
+        else
+            LOGE "Panel restart failed, Please check the log information later"
+        fi
+        if [[ $# == 0 ]]; then
+            before_show_menu
+        fi
+        return 0
+    fi
     if [[ $release == "alpine" ]]; then
         rc-service x-ui restart
     else
@@ -463,6 +510,19 @@ restart() {
 }
 
 restart_xray() {
+    if [[ "${running_in_docker}" == "true" ]]; then
+        if signal_xui USR1; then
+            LOGI "xray-core Restart signal sent successfully, Please check the log information to confirm whether xray restarted successfully"
+        else
+            LOGE "Could not find the running panel process to signal."
+        fi
+        sleep 2
+        show_xray_status
+        if [[ $# == 0 ]]; then
+            before_show_menu
+        fi
+        return 0
+    fi
     if [[ $release == "alpine" ]]; then
         rc-service x-ui reload
     else
@@ -477,6 +537,13 @@ restart_xray() {
 }
 
 status() {
+    if [[ "${running_in_docker}" == "true" ]]; then
+        show_status
+        if [[ $# == 0 ]]; then
+            before_show_menu
+        fi
+        return 0
+    fi
     if [[ $release == "alpine" ]]; then
         rc-service x-ui status
     else
@@ -488,6 +555,14 @@ status() {
 }
 
 enable() {
+    if [[ "${running_in_docker}" == "true" ]]; then
+        LOGI "Autostart is controlled by the Docker restart policy (e.g. 'restart: unless-stopped' in docker-compose.yml)."
+        LOGI "There is no service to enable inside the container."
+        if [[ $# == 0 ]]; then
+            before_show_menu
+        fi
+        return 0
+    fi
     if [[ $release == "alpine" ]]; then
         rc-update add x-ui default
     else
@@ -505,6 +580,14 @@ enable() {
 }
 
 disable() {
+    if [[ "${running_in_docker}" == "true" ]]; then
+        LOGI "Autostart is controlled by the Docker restart policy (e.g. 'restart: unless-stopped' in docker-compose.yml)."
+        LOGI "Set 'restart: no' for the container on the host to disable autostart."
+        if [[ $# == 0 ]]; then
+            before_show_menu
+        fi
+        return 0
+    fi
     if [[ $release == "alpine" ]]; then
         rc-update del x-ui
     else
@@ -673,8 +756,31 @@ update_shell() {
     fi
 }
 
+xui_pid() {
+    ps -ef 2> /dev/null | grep -F "${xui_folder}/x-ui" | grep -v grep | awk 'NR==1 {print $1}'
+}
+
+signal_xui() {
+    local sig="$1" pid
+    pid="$(xui_pid)"
+    if [[ -z "${pid}" ]]; then
+        return 1
+    fi
+    kill -"${sig}" "${pid}" 2> /dev/null
+}
+
 # 0: running, 1: not running, 2: not installed
 check_status() {
+    if [[ "${running_in_docker}" == "true" ]]; then
+        if [[ ! -x "${xui_folder}/x-ui" ]]; then
+            return 2
+        fi
+        if [[ -n "$(xui_pid)" ]]; then
+            return 0
+        else
+            return 1
+        fi
+    fi
     if [[ $release == "alpine" ]]; then
         if [[ ! -f /etc/init.d/x-ui ]]; then
             return 2
@@ -761,6 +867,10 @@ show_status() {
 }
 
 show_enable_status() {
+    if [[ "${running_in_docker}" == "true" ]]; then
+        echo -e "Start automatically: ${green}Managed by Docker${plain}"
+        return
+    fi
     check_enabled
     if [[ $? == 0 ]]; then
         echo -e "Start automatically: ${green}Yes${plain}"