Fantom-foundation/go-lachesis

package errlock

import (
    "io/ioutil"
    "os"
    "path"

    "github.com/ethereum/go-ethereum/cmd/utils"
)

// Check if errlock is written
func Check() {
    locked, reason, eLockPath, _ := read(datadir)
    if locked {
        utils.Fatalf("Node isn't allowed to start due to a previous error. Please fix the issue and then delete file \"%s\".\nError message:\n%s", eLockPath, reason)
    }
}

var (
    datadir string
)

// SetDefaultDatadir for errlock files
func SetDefaultDatadir(dir string) {
    datadir = dir
}

// Permanent error
func Permanent(err error) {
    eLockPath, _ := write(datadir, err.Error())
    utils.Fatalf("Node is stopping due to an issue. Please fix the issue and then delete file \"%s\".\nError message:\n%s", eLockPath, err.Error())
}

// read errlock file
func read(dir string) (bool, string, string, error) {
    eLockPath := path.Join(dir, "errlock")

    data, err := os.Open(eLockPath)
    if err != nil {
        return false, "", eLockPath, err
    }
    defer data.Close()

    // read no more than N bytes
    maxFileLen := 5000
    eLockBytes := make([]byte, maxFileLen)
    n, err := data.Read(eLockBytes)
    if err != nil {
        return true, "", eLockPath, err
    }
    return true, string(eLockBytes[:n]), eLockPath, nil
}

// write errlock file
func write(dir string, eLockStr string) (string, error) {
    eLockPath := path.Join(dir, "errlock")

    return eLockPath, ioutil.WriteFile(eLockPath, []byte(eLockStr), 0666) // assume no custom encoding needed
}