kvm/internal/network/hostname.go

138 lines
3.0 KiB
Go

package network
import (
"fmt"
"io"
"os"
"os/exec"
"strings"
"sync"
"golang.org/x/net/idna"
)
const (
hostnamePath = "/etc/hostname"
hostsPath = "/etc/hosts"
)
var (
hostnameLock sync.Mutex = sync.Mutex{}
)
func updateEtcHosts(hostname string, fqdn string) error {
// update /etc/hosts
hostsFile, err := os.OpenFile(hostsPath, os.O_RDWR|os.O_SYNC, os.ModeExclusive)
if err != nil {
return fmt.Errorf("failed to open %s: %w", hostsPath, err)
}
defer hostsFile.Close()
// read all lines
if _, err := hostsFile.Seek(0, io.SeekStart); err != nil {
return fmt.Errorf("failed to seek %s: %w", hostsPath, err)
}
lines, err := io.ReadAll(hostsFile)
if err != nil {
return fmt.Errorf("failed to read %s: %w", hostsPath, err)
}
newLines := []string{}
hostLine := fmt.Sprintf("127.0.1.1\t%s %s", hostname, fqdn)
hostLineExists := false
for _, line := range strings.Split(string(lines), "\n") {
if strings.HasPrefix(line, "127.0.1.1") {
hostLineExists = true
line = hostLine
}
newLines = append(newLines, line)
}
if !hostLineExists {
newLines = append(newLines, hostLine)
}
if err := hostsFile.Truncate(0); err != nil {
return fmt.Errorf("failed to truncate %s: %w", hostsPath, err)
}
if _, err := hostsFile.Seek(0, io.SeekStart); err != nil {
return fmt.Errorf("failed to seek %s: %w", hostsPath, err)
}
if _, err := hostsFile.Write([]byte(strings.Join(newLines, "\n"))); err != nil {
return fmt.Errorf("failed to write %s: %w", hostsPath, err)
}
return nil
}
func ToValidHostname(hostname string) string {
ascii, err := idna.Lookup.ToASCII(hostname)
if err != nil {
return ""
}
return ascii
}
func SetHostname(hostname string, fqdn string) error {
hostnameLock.Lock()
defer hostnameLock.Unlock()
hostname = ToValidHostname(strings.TrimSpace(hostname))
fqdn = ToValidHostname(strings.TrimSpace(fqdn))
if hostname == "" {
return fmt.Errorf("invalid hostname: %s", hostname)
}
if fqdn == "" {
fqdn = hostname
}
// update /etc/hostname
if err := os.WriteFile(hostnamePath, []byte(hostname), 0644); err != nil {
return fmt.Errorf("failed to write %s: %w", hostnamePath, err)
}
// update /etc/hosts
if err := updateEtcHosts(hostname, fqdn); err != nil {
return fmt.Errorf("failed to update /etc/hosts: %w", err)
}
// run hostname
if err := exec.Command("hostname", "-F", hostnamePath).Run(); err != nil {
return fmt.Errorf("failed to run hostname: %w", err)
}
return nil
}
func (s *NetworkInterfaceState) setHostnameIfNotSame() error {
hostname := s.GetHostname()
currentHostname, _ := os.Hostname()
fqdn := fmt.Sprintf("%s.%s", hostname, s.GetDomain())
if currentHostname == hostname && s.currentFqdn == fqdn && s.currentHostname == hostname {
return nil
}
scopedLogger := s.l.With().Str("hostname", hostname).Str("fqdn", fqdn).Logger()
err := SetHostname(hostname, fqdn)
if err != nil {
scopedLogger.Error().Err(err).Msg("failed to set hostname")
return err
}
s.currentHostname = hostname
s.currentFqdn = fqdn
scopedLogger.Info().Msg("hostname set")
return nil
}