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Fix #11589 by adding README and comments to exported functions

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Signed-off-by: Arthur Barr <arthur.barr@uk.ibm.com>
This commit is contained in:
Arthur Barr 2015-03-24 07:12:59 +00:00
parent 4b4bdb5be5
commit 557cca536f
2 changed files with 11 additions and 5 deletions
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1
pkg/resolvconf/README.md Normal file
View file

@ -0,0 +1 @@
Package resolvconf provides utility code to query and update DNS configuration in /etc/resolv.conf

15
pkg/resolvconf/resolvconf.go
View file

@ -1,3 +1,4 @@
// Package resolvconf provides utility code to query and update DNS configuration in /etc/resolv.conf
package resolvconf
import (
@ -38,6 +39,7 @@ var lastModified struct {
contents []byte
}
// Get returns the contents of /etc/resolv.conf
func Get() ([]byte, error) {
resolv, err := ioutil.ReadFile("/etc/resolv.conf")
if err != nil {
@ -46,7 +48,7 @@ func Get() ([]byte, error) {
return resolv, nil
}
// Retrieves the host /etc/resolv.conf file, checks against the last hash
// GetIfChanged retrieves the host /etc/resolv.conf file, checks against the last hash
// and, if modified since last check, returns the bytes and new hash.
// This feature is used by the resolv.conf updater for containers
func GetIfChanged() ([]byte, string, error) {
@ -70,7 +72,7 @@ func GetIfChanged() ([]byte, string, error) {
return nil, "", nil
}
// retrieve the last used contents and hash of the host resolv.conf
// GetLastModified retrieves the last used contents and hash of the host resolv.conf.
// Used by containers updating on restart
func GetLastModified() ([]byte, string) {
lastModified.Lock()
@ -79,14 +81,14 @@ func GetLastModified() ([]byte, string) {
return lastModified.contents, lastModified.sha256
}
// FilterResolvDns has two main jobs:
// FilterResolvDns cleans up the config in resolvConf. It has two main jobs:
// 1. It looks for localhost (127.*|::1) entries in the provided
// resolv.conf, removing local nameserver entries, and, if the resulting
// cleaned config has no defined nameservers left, adds default DNS entries
// 2. Given the caller provides the enable/disable state of IPv6, the filter
// code will remove all IPv6 nameservers if it is not enabled for containers
//
// It also returns a boolean to notify the caller if changes were made at all
// It returns a boolean to notify the caller if changes were made at all
func FilterResolvDns(resolvConf []byte, ipv6Enabled bool) ([]byte, bool) {
changed := false
cleanedResolvConf := localhostNSRegexp.ReplaceAll(resolvConf, []byte{})
@ -126,7 +128,7 @@ func getLines(input []byte, commentMarker []byte) [][]byte {
return output
}
// returns true if the IP string matches the localhost IP regular expression.
// IsLocalhost returns true if ip matches the localhost IP regular expression.
// Used for determining if nameserver settings are being passed which are
// localhost addresses
func IsLocalhost(ip string) bool {
@ -171,6 +173,9 @@ func GetSearchDomains(resolvConf []byte) []string {
return domains
}
// Build writes a configuration file to path containing a "nameserver" entry
// for every element in dns, and a "search" entry for every element in
// dnsSearch.
func Build(path string, dns, dnsSearch []string) error {
content := bytes.NewBuffer(nil)
for _, dns := range dns {