#!/bin/sh
# S'assurer que BackupPC peux exécuter rsync avec les droits sudo
# Jérémy GARDAIS — Mai 2018

# .. vim: foldmarker=[[[,]]]:foldmethod=marker

# Vars [[[
SUCCESS=0
ERROR=1
DEBUG=1
USER_ID=$(id -u)

BACKUP_USER_LIST="backup backuppc"
BACKUP_SUDOERS_LINE_REGEXP="backuppc.*ALL.*=.*(ALL:ALL).*NOEXEC:NOPASSWD:.*/usr/bin/rsync"
BACKUP_SUDOERS_LINE="backup ALL=(ALL:ALL) NOEXEC:NOPASSWD: /usr/bin/rsync
backuppc ALL=(ALL:ALL) NOEXEC:NOPASSWD: /usr/bin/rsync"
BACKUP_SUDOERS_FILE="/etc/sudoers.d/backuppc_noexec"
# ]]]

# Functions [[[

## Check if a backup user is present on the system from a list of users  [[[
is_backup_user()
{
	userlist_to_check="${1}"

	for user_to_check in ${userlist_to_check}; do
		if [ "$(id -- "${user_to_check}" 2> /dev/null)" ] ; then
			[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : Function is_backup_user() — ${user_to_check} user is available."
			return "${SUCCESS}"
		fi
	done

	## Otherwise exit with error status
	printf '\e[1;31m%-6s\e[m\n' "ERROR : Function is_backup_user() — none of these users : ${userlist_to_check} are available on the system."
	exit "${ERROR}"
}
## ]]]
## Check if backup permissions are already set in sudoers.d  [[[
is_backup_sudoers_line()
{
	line_to_check="${1}"

	if grep -Rq -- "${line_to_check}" /etc/sudoers.d/
	then
		[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : Function is_backup_sudoers_line() — ${line_to_check} line is available in sudo configuration."
		return "${SUCCESS}"
	else
		[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : Function is_backup_sudoers_line() — ${line_to_check} was not found in sudo configuration."
		return "${ERROR}"
	fi
}
## ]]]
## Add some configuration to a specific file under sudoers.d/  [[[
add_backup_sudoers_conf()
{
	sudoers_conf="${1}"
	sudoers_file="${2}"

	## Empty sudoers file
	true > "${sudoers_file}"

	## Set sudoers configuration for BackupPC
	cat << EOF >> "${sudoers_file}"
# This file was generated by fix_backuppc_linux_sudo.sh script.

# Permissions for BackupPC - Backup tool
${sudoers_conf}
EOF

	[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : Function add_backup_sudoers_conf() — ${sudoers_file} was modified."
}
## ]]]
# ]]]

# Test permissions [[[
[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : Check admin rights."
if [ "${USER_ID}" -ne "0" ]; then
	printf '\e[1;31m%-6s\e[m\n' "ERROR : You need to run with SUDO/Admin permissions."
	exit "${ERROR}"
fi
# ]]]

# Ensure the backup user is available
is_backup_user "${BACKUP_USER_LIST}"

# Test if sudoers conf is already set
if ! is_backup_sudoers_line "${BACKUP_SUDOERS_LINE_REGEXP}"
then
	[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : First try — ${BACKUP_SUDOERS_LINE_REGEXP} was not found in sudo configuration."
	## Add sudoers configuration
	add_backup_sudoers_conf "${BACKUP_SUDOERS_LINE}" "${BACKUP_SUDOERS_FILE}"

	## Test if sudoers conf was successfully modified
	if ! is_backup_sudoers_line "${BACKUP_SUDOERS_LINE_REGEXP}"
	then
		[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : Second try — ${BACKUP_SUDOERS_LINE_REGEXP} was not found in sudo configuration."
		printf '\e[1;31m%-6s\e[m\n' "ERROR : The sudo configuration was not successfully modified."
		printf '\e[1;31m%-6s\e[m\n' "ERROR : Please contact your administrator."
		exit "${ERROR}"
	fi
fi

[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6s\e[m\n' "DEBUG : End"

printf '%b\n' "Your configuration is set up."

exit "${SUCCESS}"