#!/bin/sh -e
# Script to save core files, to be run from post_crash_dump_hook
# Written by Markus Armbruster, 2008-2012
# This script is in the public domain.

# Use: edit configuration variables below to taste, then set
#   post_crash_dump_hook = /wherever/savecore
# in econfig.  Make sure to run the server with core dumps enabled
# (ulimit -c unlimited).

# Rules when running as post_crash_dump_hook:
# Data directory is working directory.
# stdin, stdout, stderr are redirected to /dev/null, except in debug
# mode

# Configuration

# How your system names core files
#
# This is a pattern rather than a name, because modern kernels can put
# fancy stuff in the name we can't always predict.  Modern user space
# can squirrel away core dumps in fancy places; you may need to switch
# that off for this insufficiently fancy script to work.
core_pattern=core.*
#core_pattern=emp_server.core
#core_pattern=core

# Where to save core dumps
#
# If you leave cores in the data directory, backup scripts may pick
# them up, which is probably not what you want.
core_dir=../core-dumps

# Minimum free disk space for saving core dumps, in KiB
space_low=102400

# Whom to send mail (leave empty to not send any)
privlog=

# Program to send mail
mailx=mailx

# End of configuration

saved=
core_name=

alert_deity ()
{
    local msg
    if [ "$saved" ]
    then msg="Core dump $saved_core saved."
    elif [ "$core_name" ]
    then msg="Could not save core dump $core_name."
    else msg="Could not find core dump to save."
    fi
    echo "$msg" | $mailx -s "emp_server dumped core in $PWD" "$privlog"
}

test -n "$privlog" && trap 'alert_deity' EXIT

core_name=`ls -td $core_pattern 2>/dev/null | head -n 1`
test -n "$core_name"
test -r "$core_name"
tstamp=`/bin/date +%Y-%m-%d-%H:%M`
saved_core=$core_dir/core-$tstamp

mkdir -p $core_dir
if [ `df -kP $core_dir | awk 'NR!=1 { print $4 }'` -lt "$space_low" ]
then rm -f "$core_name"; exit
fi

mv -f "$core_name" $saved_core
saved=y