Merge branch 'rani/inet_gethostbyname_fixes' into ccase/r13b04_dev

* rani/inet_gethostbyname_fixes:
  inet_res_SUITE: testcase fixes for legacy DNS resolver (Solaris 8)
  inet_res: /etc/resolv.conf: use domain as default search list
  inet: delayed/avoided read of /etc/resolv.conf and /etc/hosts
  inet_gethost_native: workaround for empty result hostname on MacOS X
  inet_res_SUITE: testcase fix for empty domain name
  inet:gethostbyname improved to parse IP strings and look up own hostname

OTP-8426  The resolver routines failed to look up the own node name as
          hostname, if the OS native resolver was erroneously configured,
          bug reported by Yogish Baliga, now fixed.

          The resolver routines now tries to parse the hostname as an IP
          string as most OS resolvers do, unless the native resolver is
          used.

          The DNS resolver inet_res and file resolver inet_hosts now do not
          read OS configuration files until they are needed. Since the
          native resolver is default, in most cases they are never needed.

          The DNS resolver's automatic updating of OS configuration file
          data (/etc/resolv.conf) now uses the 'domain' keyword as default
          search domain if there is no 'search' keyword.

1 files changed, 65 insertions, 23 deletions

diff --git a/lib/kernel/test/inet_res_SUITE.erl b/lib/kernel/test/inet_res_SUITE.erl
index 659cfc5988..cc32d1f8f9 100644
--- a/lib/kernel/test/inet_res_SUITE.erl
+++ b/lib/kernel/test/inet_res_SUITE.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 2009-2010. All Rights Reserved.
+%%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
 %% compliance with the License. You should have received a copy of the
 %% Erlang Public License along with this software. If not, it can be
 %% retrieved online at http://www.erlang.org/.
-%% 
+%%
 %% Software distributed under the License is distributed on an "AS IS"
 %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 %% the License for the specific language governing rights and limitations
 %% under the License.
-%% 
+%%
 %% %CopyrightEnd%
 %%
 -module(inet_res_SUITE).
@@ -239,16 +239,37 @@ resolve(_Opts, []) -> ok;
 resolve(Opts, [{Class,Type,Name,Answers,Authority}=Q|Qs]) ->
     io:format("Query: ~p~nOptions: ~p~n", [Q,Opts]),
     {ok,Msg} = inet_res:resolve(Name, Class, Type, Opts),
-    if Answers =/= undefined ->
-	    AnList = lists:sort(Answers),
-	    AnList = lists:sort([inet_dns:rr(RR, data) ||
-				    RR <- inet_dns:msg(Msg, anlist)]);
-       true -> ok end,
-    if Authority =/= undefined ->
-	    NsList = lists:sort(Authority),
-	    NsList = lists:sort([inet_dns:rr(RR, data) ||
-				    RR <- inet_dns:msg(Msg, nslist)]);
-       true -> ok end,
+    AnList =
+	if
+	    Answers =/= undefined ->
+		lists:sort(Answers);
+	    true ->
+		undefined
+	end,
+    NsList =
+	if
+	    Authority =/= undefined ->
+		lists:sort(Authority);
+	    true ->
+		undefined
+	end,
+    case {lists:sort
+	  ([inet_dns:rr(RR, data) || RR <- inet_dns:msg(Msg, anlist)]),
+	  lists:sort
+	  ([inet_dns:rr(RR, data) || RR <- inet_dns:msg(Msg, nslist)])} of
+	{AnList,NsList} ->
+	    ok;
+	{NsList,AnList} when Type =:= ns ->
+	    %% This whole case statement is kind of inside out just
+	    %% to accept this case when some legacy DNS resolvers
+	    %% return the answer to a NS query in the answer section
+	    %% instead of in the authority section.
+	    ok;
+	{AnList,_} when NsList =:= undefined ->
+	    ok;
+	{_,NsList} when AnList =:= undefined ->
+	    ok
+    end,
     Buf = inet_dns:encode(Msg),
     {ok,Msg} = inet_dns:decode(Buf),
     resolve(Opts, Qs).
@@ -292,10 +313,23 @@ edns0(Config) when is_list(Config) ->
     MXs = lists:sort(inet_res_filter(inet_dns:msg(Msg2, anlist), in, mx)),
     Buf2 = inet_dns:encode(Msg2),
     {ok,Msg2} = inet_dns:decode(Buf2),
-    [OptRR] = [RR || RR <- inet_dns:msg(Msg2, arlist),
-		     inet_dns:rr(RR, type) =:= opt],
-    io:format("~p~n", [inet_dns:rr(OptRR)]),
-    ok.
+    case [RR || RR <- inet_dns:msg(Msg2, arlist),
+		inet_dns:rr(RR, type) =:= opt] of
+	[OptRR] ->
+	    io:format("~p~n", [inet_dns:rr(OptRR)]),
+	    ok;
+	[] ->
+	    case os:type() of
+		{unix,sunos} ->
+		    case os:version() of
+			{M,V,_} when M < 5;  M == 5, V =< 8 ->
+			    %% In our test park only known platform
+			    %% with an DNS resolver that can not do
+			    %% EDNS0.
+			    {comment,"No EDNS0"}
+		    end
+	    end
+    end.
 
 inet_res_filter(Anlist, Class, Type) ->
     [inet_dns:rr(RR, data) || RR <- Anlist,
@@ -331,11 +365,13 @@ files_monitor(suite) ->
 files_monitor(doc) ->
     ["Tests monitoring of /etc/hosts and /etc/resolv.conf, but not them"];
 files_monitor(Config) when is_list(Config) ->
+    Search = inet_db:res_option(search),
     HostsFile = inet_db:res_option(hosts_file),
     ResolvConf = inet_db:res_option(resolv_conf),
     Inet6 = inet_db:res_option(inet6),
     try do_files_monitor(Config)
     after
+        inet_db:res_option(search, Search),
         inet_db:res_option(resolv_conf, ResolvConf),
 	inet_db:res_option(hosts_file, HostsFile),
 	inet_db:res_option(inet6, Inet6)
@@ -344,7 +380,13 @@ files_monitor(Config) when is_list(Config) ->
 do_files_monitor(Config) ->
     Dir = ?config(priv_dir, Config),
     {ok,Hostname} = inet:gethostname(),
-    FQDN = Hostname++"."++inet_db:res_option(domain),
+    FQDN =
+	case inet_db:res_option(domain) of
+	    "" ->
+		Hostname;
+	    _ ->
+		Hostname++"."++inet_db:res_option(domain)
+	end,
     HostsFile = filename:join(Dir, "files_monitor_hosts"),
     ResolvConf = filename:join(Dir, "files_monitor_resolv.conf"),
     ok = inet_db:res_option(resolv_conf, ResolvConf),
@@ -362,20 +404,20 @@ do_files_monitor(Config) ->
     {error,nxdomain} = inet_res:gethostbyname(FQDN),
     {ok,{127,0,0,10}} = inet:getaddr("mx.otptest", inet),
     {ok,{0,0,0,0,0,0,32512,28}} = inet:getaddr("resolve.otptest", inet6),
-    ok = inet_db:res_option(inet6, true),
     {ok,#hostent{h_name = Hostname,
 		 h_addrtype = inet6,
 		 h_length = 16,
 		 h_addr_list = [{0,0,0,0,0,0,0,1}]}} =
-	inet:gethostbyname(Hostname),
+	inet:gethostbyname(Hostname, inet6),
     {ok,#hostent{h_name = FQDN,
 		 h_addrtype = inet6,
 		 h_length = 16,
 		 h_addr_list = [{0,0,0,0,0,0,0,1}]}} =
-	inet:gethostbyname(FQDN),
+	inet:gethostbyname(FQDN, inet6),
     {error,nxdomain} = inet_res:gethostbyname("resolve"),
     %% XXX inet does not honour res_option inet6, might be a problem?
     %% therefore inet_res is called here
+    ok = inet_db:res_option(inet6, true),
     {ok,#hostent{h_name = "resolve.otptest",
 		 h_addrtype = inet6,
 		 h_length = 16,