//go:build !darwin

package main

import (
	"fmt"
	"os"
	"runtime"
)

// mountInfoPath is the file in which Linux lists the mounts the reading
// process sees.
const mountInfoPath = "/proc/self/mountinfo"

// nonPersistentFilesystems returns the device ID of every mounted
// filesystem that is not persistent, with its type: on Linux read from
// mountInfoPath (see readMountInfo), and on any other system none.
func nonPersistentFilesystems() (map[uint64]string, error) {
	if runtime.GOOS != goosLinux {
		return map[uint64]string{}, nil
	}

	f, err := os.Open(mountInfoPath)
	if err != nil {
		return nil, err
	}

	defer func() { _ = f.Close() }()

	devices, err := readMountInfo(f)
	if err != nil {
		return nil, fmt.Errorf("read %s: %w", mountInfoPath, err)
	}

	return devices, nil
}