#!/bin/bash
# Copyright (C) 2019 Checkmk GmbH - License: GNU General Public License v2
# This file is part of Checkmk (https://checkmk.com). It is subject to the terms and
# conditions defined in the file COPYING, which is part of this source code package.

# Reason for this no-op: shellcheck disable=... before the first command disables the error for the
# entire script.
:

# Disable unused variable error (needed to keep track of version)
# shellcheck disable=SC2034
CMK_VERSION="2.3.0p38"

# This plugin allows to execute mrpe, local and plugin skripts with a different user context
# It is configured with in the file $MK_CONFDIR/runas.cfg
#
# Syntax:
# [Script type] [User context] [File / Directory]
#
# Example configuration
# # Execute mrpe commands in given files under specific user
# # A '-' means no user context switch
# mrpe ab /home/ab/mrpe_commands.cfg
# mrpe lm /home/lm/mrpe_commands.cfg
# mrpe - /root/mrpe/extra_commands.cfg
#
# Excecute -executable- files in the target directories under specific user context
# plugin ab /var/ab/plugins
# local ab /var/ab/local
#

# SC2162: read without -r will mangle backslashes.
# The following suppression was added when we enabled the corresponding shellcheck.
# It may well be that "read -r" would be more appropriate (for all of the three read commands).
# shellcheck disable=SC2162
grep -Ev '^[[:space:]]*($|#)' "$MK_CONFDIR/runas.cfg" |
    while read type user include; do
        if [ -d "${include}" ] || { [ "${type}" = "mrpe" ] && [ -f "${include}" ]; }; then
            PREFIX=""
            if [ "$user" != "-" ]; then
                PREFIX="su $user -c "
            fi

            # mrpe includes
            if [ "$type" == "mrpe" ]; then
                echo "<<<mrpe>>>"
                grep -Ev '^[[:space:]]*($|#)' "$include" |
                    while read descr cmdline; do
                        PLUGIN=${cmdline%% *}
                        #  shellcheck disable=SC2030 # false positive? "Modification of PREFIX is local..."
                        if [ -n "$PREFIX" ]; then
                            cmdline="$PREFIX\"$cmdline\""
                        fi
                        OUTPUT=$(eval "$cmdline")
                        echo -n "(${PLUGIN##*/}) $descr $? $OUTPUT" | tr \\n \\1
                        echo
                    done
            # local and plugin includes
            elif [ "$type" = "local" ] || [ "$type" = "plugin" ]; then
                if [ "$type" == "local" ]; then
                    echo "<<<local:sep(0)>>>"
                fi
                find "$include" -executable -type f |
                    while read filename; do
                        # shellcheck disable=SC2031 # false positive? "PREFIX was modified in a subshell..."
                        if [ -n "$PREFIX" ]; then
                            cmdline="$PREFIX\"$filename\""
                        else
                            cmdline=$filename
                        fi
                        $cmdline
                    done
            fi
        fi
    done