97 lines
1.7 KiB
Go
97 lines
1.7 KiB
Go
package server
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import (
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"fmt"
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"io"
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"os"
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"strings"
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)
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const (
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// According to http://man7.org/linux/man-pages/man5/resolv.conf.5.html:
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// "The search list is currently limited to six domains with a total of 256 characters."
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maxDNSSearches = 6
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)
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func int64Ptr(i int64) *int64 {
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return &i
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}
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func int32Ptr(i int32) *int32 {
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return &i
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}
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func sPtr(s string) *string {
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return &s
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}
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func copyFile(src, dest string) error {
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in, err := os.Open(src)
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if err != nil {
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return err
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}
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defer in.Close()
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out, err := os.Create(dest)
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if err != nil {
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return err
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}
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defer out.Close()
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_, err = io.Copy(out, in)
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return err
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}
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func removeFile(path string) error {
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if _, err := os.Stat(path); err == nil {
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if err := os.Remove(path); err != nil {
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return err
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}
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}
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return nil
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}
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func parseDNSOptions(servers, searches, options []string, path string) error {
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nServers := len(servers)
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nSearches := len(searches)
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nOptions := len(options)
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if nServers == 0 && nSearches == 0 && nOptions == 0 {
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return copyFile("/etc/resolv.conf", path)
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}
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if nSearches > maxDNSSearches {
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return fmt.Errorf("DNSOption.Searches has more than 6 domains")
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}
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f, err := os.Create(path)
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if err != nil {
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return err
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}
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defer f.Close()
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if nSearches > 0 {
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data := fmt.Sprintf("search %s\n", strings.Join(searches, " "))
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_, err = f.Write([]byte(data))
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if err != nil {
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return err
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}
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}
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if nServers > 0 {
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data := fmt.Sprintf("nameserver %s\n", strings.Join(servers, "\nnameserver "))
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_, err = f.Write([]byte(data))
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if err != nil {
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return err
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}
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}
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if nOptions > 0 {
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data := fmt.Sprintf("options %s\n", strings.Join(options, " "))
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_, err = f.Write([]byte(data))
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if err != nil {
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return err
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}
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}
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return nil
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}
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