#!/bin/sh
#
# 2016 Daniel Heule (hda at sfs.biz)
# Copyright 2017, Philippe Gregoire <pg@pgregoire.xyz>
#
# This file is part of cdist.
#
# cdist is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# cdist is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with cdist. If not, see <http://www.gnu.org/licenses/>.
#
#
# Returns the process name of pid 1 ( normaly the init system )
# for example at linux this value is "init" or "systemd" in most cases
#

case $(uname -s) in
    Linux)
        if command -v pgrep >/dev/null
        then
            # BusyBox's version of ps does not support some options.
            # On Linux systems, we prefer pgrep to get the name of PID1.
            (pgrep -P0 -l | awk '/^1[ \t]/ {print $2;}') || true
        else
            ps -o comm= -p 1 2>/dev/null || cat /proc/1/comm
        fi
    ;;
    FreeBSD|OpenBSD)
        ps -o comm= -p 1 2>/dev/null || true
    ;;
    Darwin)
        basename "$(ps -o comm= -p 1 2>/dev/null)"
    ;;
    *)
        # return a empty string as unknown value
        echo ""
    ;;
esac