#!/bin/sh
#
# Simple Bourne Shell script that implements Munin protocol and
# some common Linux plugins.
#
# For latest version, see http://muninlite.sf.net/
#
# Copyright (c) 2007-2011 Rune Nordbøe Skillingstad <rune@skillingstad.no>
#
# Licensed under GPLv2 (see LICENSE file for full License)
#

VERSION="@@VERSION@@"

set -eu

@@CONF@@

# Name of runtime configuration file
CONFIG_FILE=/etc/munin/muninlite.conf

# if plugindir_ is present in $PLUGINS, executables (scripts, binaries) in the specified path
# and matching the pattern will be scanned and operated as plugins
PLUGIN_DIRECTORY=/etc/munin/plugins
PLUGINPATTERN="*"

# Remove unwanted plugins from this list
PLUGINS="@@PLUGINS@@"
# ===== LIB FUNCTIONS =====
clean_fieldname() {
  echo "$@" | sed -e 's/^[^A-Za-z_]/_/' -e 's/[^A-Za-z0-9_]/_/g'
}

# ===== PLUGINS CODE =====
@@PLSTR@@

# ===== NODE CODE =====
do_list() {
  echo "$PLUGINS"
}


do_nodes() {
  echo "$HOSTNAME"
  echo "."
}

do_config() {
  if echo "$PLUGINS" | grep -qwF "$1"; then
    "config_$1"
  else
    echo "# Unknown service"
  fi
  echo "."
}

do_fetch() {
  if echo "$PLUGINS" | grep -qwF "$1"; then
    "fetch_$1"
  else
    echo "# Unknown service"
  fi
  echo "."
}

do_version() {
  echo "munins node on $HOSTNAME version: $VERSION (muninlite)"
}

do_quit() {
  exit 0
}

# ===== Runtime config =====
# shellcheck source=/dev/null
[ -f ${CONFIG_FILE} ] && . ${CONFIG_FILE}
RES=""
for PLUG in $PLUGINS; do
  case "$PLUG" in
    if_|if_err_)
      if [ -z "$INTERFACE_NAMES_OVERRIDE" ]; then
        interface_names=$(sed 's/^ *//; s/:.*$//; / /d; /^lo$/d' /proc/net/dev)
      else
        interface_names="$INTERFACE_NAMES_OVERRIDE"
      fi
      for INTER in $interface_names; do
        INTERRES=$(echo "$INTER" | sed -e 's/\./VLAN/' -e 's/\-/_/g')
        RES="$RES ${PLUG}${INTERRES}"
        eval "fetch_${PLUG}${INTERRES}() { 'fetch_${PLUG%_}' '$INTER'; }"
        eval "config_${PLUG}${INTERRES}() { 'config_${PLUG%_}' '$INTER'; }"
      done
      ;;
    netstat)
      if netstat -s >/dev/null 2>&1; then
        RES="$RES netstat"
      fi
      ;;
    wireless)
      if iwinfo >/dev/null 2>&1; then
          RES="${RES} ${PLUG}"
      fi
      ;;
    plugindir_)
      for MYPLUGIN in $(if [ -d "$PLUGIN_DIRECTORY" ]; then find -L "$PLUGIN_DIRECTORY" -type f -name "$PLUGINPATTERN"; fi); do
        if [ -f "$MYPLUGIN" ] && [ -x "$MYPLUGIN" ]; then
          # generate a name suitable for shell function names
          MYPLUGINNAME=$(basename "$MYPLUGIN" | sed 's/[^0-9a-zA-Z_]/_/g')
          # detect and avoid name collision
          if echo "$RES" | grep -qwF "$MYPLUGINNAME"; then
            MYPLUGINNAME="plugindir_$MYPLUGINNAME"
          fi
          RES="$RES $MYPLUGINNAME"
          eval "fetch_${MYPLUGINNAME}() { '$MYPLUGIN'; }"
          eval "config_${MYPLUGINNAME}() { '$MYPLUGIN' config; }"
        fi
      done
      ;;
    *)
      RES="$RES $PLUG"
      ;;
  esac
done
# sort plugin names and remove surrounding whitespace
PLUGINS=$(echo "$RES" | xargs -r -n 1 echo | sort | xargs echo)

# ===== MAIN LOOP =====
FUNCTIONS="list nodes config fetch version quit"
HOSTNAME=$( { hostname -f || hostname || cat /proc/sys/kernel/hostname || echo "unknown"; } 2>/dev/null )
echo "# munin node at $HOSTNAME"
while read -r arg0 arg1
do
  arg0=$(printf '%s\n' "$arg0" | xargs)
  arg1=$(printf '%s\n' "$arg1" | xargs)
  if ! echo "$FUNCTIONS" | grep -qwF -- "$arg0"; then
    echo "# Unknown command. Try $(echo "$FUNCTIONS" | sed -e 's/\( [[:alpha:]]\{1,\}\)/,\1/g' -e 's/,\( [[:alpha:]]\{1,\}\)$/ or\1/')"
  elif [ -n "$arg0" ]; then
    "do_$arg0" "$arg1"
  fi
done