| package iso |
| |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| import ( |
| "bufio" |
| "io" |
| "net" |
| "os" |
| "strings" |
| ) |
| |
| // readDefaultUnixResolve reads the /etc/resolv.conf |
| // file and parses out the nameservers. |
| func readDefaultUnixResolve() ([]string, error) { |
| fd, err := os.Open("/etc/resolv.conf") |
| if err != nil { |
| return nil, err |
| } |
| defer fd.Close() |
| return parseResolve(fd) |
| } |
| |
| // parseResolve parses r as a resolv.conf formatted string. |
| // It returns all the nameservers found in the file. Any |
| // formatting or other issues within the file itself are ignored, |
| // only errors reading from r are returned. |
| // See following link for more information: |
| // http://man7.org/linux/man-pages/man5/resolv.conf.5.html |
| func parseResolve(r io.Reader) ([]string, error) { |
| var nameservers []string |
| |
| s := bufio.NewScanner(r) |
| for s.Scan() { |
| l := s.Text() |
| if len(l) > 0 && (l[0] == '#' || l[0] == ';') { |
| // Ignore comments |
| continue |
| } |
| parts := strings.Fields(l) |
| // Look for "nameserver 0.0.0.0" formatted lines |
| if len(parts) < 2 || parts[0] != "nameserver" { |
| continue |
| } |
| if net.ParseIP(parts[1]) == nil { |
| // Ignore invalid IPs |
| continue |
| } |
| nameservers = append(nameservers, parts[1]) |
| } |
| |
| return nameservers, s.Err() |
| } |