code review 5320041: net: Plan 9 fixes

src/pkg/net/lookup_plan9.go

 // Copyright 2011 The Go Authors.  All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package net
 
 import (
         "os"
 )
 
@@ skipping 31 matching lines @@
                 net = "udp"
         }
         if host == "" {
                 host = "*"
         }
         return query("/net/cs", net+"!"+host+"!"+service, 128)
 }
 
 func queryCS1(net string, ip IP, port int) (clone, dest string, err os.Error) {
         ips := "*"
-        if !ip.IsUnspecified() {
+        if len(ip) != 0 && !ip.IsUnspecified() {
                 ips = ip.String()
         }
         lines, err := queryCS(net, ips, itoa(port))
         if err != nil {
                 return
         }
         f := getFields(lines[0])
         if len(f) < 2 {
                 return "", "", os.NewError("net: bad response from ndb/cs")
         }
@@ skipping 145 matching lines @@
                 if pref, _, ok := dtoi(f[2], 0); ok {
                         mx = append(mx, &MX{f[3], uint16(pref)})
                 }
         }
         byPref(mx).sort()
         return
 }
 
 // LookupTXT returns the DNS TXT records for the given domain name.
 func LookupTXT(name string) (txt []string, err os.Error) {
-        return nil, os.NewError("net.LookupTXT is not implemented on Plan 9")
+        lines, err := queryDNS(name, "txt")
+        if err != nil {
+                return
+        }
+        for _, line := range lines {
+                if i := byteIndex(line, '\t'); i >= 0 {
+                        txt = append(txt, line[i+1:])
+                }
+        }
+        return
 }
 
 // LookupAddr performs a reverse lookup for the given address, returning a list
 // of names mapping to that address.
 func LookupAddr(addr string) (name []string, err os.Error) {
         arpa, err := reverseaddr(addr)
         if err != nil {
                 return
         }
         lines, err := queryDNS(arpa, "ptr")
         if err != nil {
                 return
         }
         for _, line := range lines {
                 f := getFields(line)
                 if len(f) < 3 {
                         continue
                 }
                 name = append(name, f[2])
         }
         return
 }