/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package kmsg

import (
	"fmt"
	"log"
	"os"

	"golang.org/x/sys/unix"
)

// Setup configures the log package to write to the kernel ring buffer via
// /dev/kmsg.
func Setup(prefix string) (*os.File, error) {
	out, err := os.OpenFile("/dev/kmsg", os.O_RDWR|unix.O_CLOEXEC|unix.O_NONBLOCK|unix.O_NOCTTY, 0666)
	if err != nil {
		return nil, fmt.Errorf("failed to open /dev/kmsg: %w", err)
	}

	log.SetOutput(out)
	log.SetPrefix(prefix + " ")
	log.SetFlags(0)

	return out, nil
}