#!/bin/sh
#
# Plugin to monitor memory usage on FreeBSD.
#
# Parameters:
#
#       config   (required)
#       autoconf (optional - only used by munin-config)
#
# Magic markers (optional - only used by munin-config and some
# installation scripts):
#%# family=auto
#%# capabilities=autoconf

if [ "$1" = "autoconf" ]; then
    if [ -x /sbin/sysctl ]; then
        if /sbin/sysctl vm.stats.vm.v_page_size > /dev/null; then
            echo yes
            exit 0
        else
            echo no
            exit 0
        fi
    else
        echo no
        exit 0
    fi
fi

PAGESIZE=$(/sbin/sysctl -n vm.stats.vm.v_page_size)
MEMSIZE=$(/sbin/sysctl -n vm.stats.vm.v_page_count)
MEMMAX=$(($PAGESIZE*$MEMSIZE))
CACHE_COUNT=$(/sbin/sysctl -n vm.stats.vm.v_cache_count)
LAUNDRY_COUNT=$(/sbin/sysctl -n vm.stats.vm.v_laundry_count)

if [ "$1" = "config" ]; then
    echo 'graph_args --base 1024 -l 0 --vertical-label Bytes --upper-limit' $MEMMAX
    echo 'graph_title Memory usage'
    echo 'graph_category system'
    echo 'graph_info This graph shows what the machine uses its memory for.'
    # assemble the graph order (including the optional items)
    printf 'graph_order active inactive wired'
    if [ -n "$CACHE_COUNT" ]; then printf ' cached'; fi
    if [ -n "$LAUNDRY_COUNT" ]; then printf ' laundry'; fi
    echo ' free swap buffers'
    echo 'active.label active'
    echo 'active.info pages recently statistically used'
    echo 'active.draw AREA'
    echo 'inactive.label inactive'
    echo 'inactive.info pages recently statistically unused'
    echo 'inactive.draw STACK'
    echo 'wired.label wired'
    echo 'wired.info pages that are fixed into memory, usually for kernel purposes, but also sometimes for special use in processes'
    echo 'wired.draw STACK'
    # the "cache" counter was removed in 2015
    if [ -n "$CACHE_COUNT" ]; then
        echo 'cached.label cache'
        echo 'cached.info pages that have percolated from inactive to a status where they maintain their data, but can often be immediately reused'
        echo 'cached.draw STACK'
    fi
    # the "laundry" counter was introduced in 2015
    if [ -n "$LAUNDRY_COUNT" ]; then
        echo 'laundry.label laundry'
        echo 'laundry.info number of dirty bytes inactive'
        echo 'laundry.draw STACK'
    fi
    echo 'free.label free'
    echo 'free.info pages without data content'
    echo 'free.draw STACK'
    echo 'swap.label swap'
    echo 'swap.info Swap space used'
    echo 'swap.draw STACK'
    echo 'buffers.label buffers'
    echo 'buffers.info pages used for filesystem buffers'
    echo 'buffers.draw LINE'
    exit 0
fi

ACTIVE_COUNT=$(/sbin/sysctl -n vm.stats.vm.v_active_count)
INACTIVE_COUNT=$(/sbin/sysctl -n vm.stats.vm.v_inactive_count)
WIRED_COUNT=$(/sbin/sysctl -n vm.stats.vm.v_wire_count)
BUFFERS_COUNT=$(/sbin/sysctl -n vfs.bufspace)
FREE_COUNT=$(/sbin/sysctl -n vm.stats.vm.v_free_count)

echo active.value $(($ACTIVE_COUNT*$PAGESIZE))
echo inactive.value $(($INACTIVE_COUNT*$PAGESIZE))
echo wired.value $(($WIRED_COUNT*$PAGESIZE))
echo buffers.value $(($BUFFERS_COUNT))
if [ -n "$CACHE_COUNT" ]; then
    echo cached.value $(($CACHE_COUNT*$PAGESIZE))
fi
if [ -n "$LAUNDRY_COUNT" ]; then
    echo "laundry.value $(( LAUNDRY_COUNT * PAGESIZE ))"
fi
echo free.value $(($FREE_COUNT*$PAGESIZE))
echo swap.value $(swapinfo -k | awk '!/^Total/ && !/^Device/ {sum += $3}; END {print sum * 1024}')