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, 196 insertions, 89 deletions

diff --git a/lib/kernel/src/inet_parse.erl b/lib/kernel/src/inet_parse.erl
index 62d44fb723..3bd5fa0958 100644
--- a/lib/kernel/src/inet_parse.erl
+++ b/lib/kernel/src/inet_parse.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 1997-2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 1997-2010. 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_parse).
@@ -34,6 +34,7 @@
 -export([nsswitch_conf/1, nsswitch_conf/2]).
 
 -export([ipv4_address/1, ipv6_address/1]).
+-export([ipv4strict_address/1, ipv6strict_address/1]).
 -export([address/1]).
 -export([visible_string/1, domain/1]).
 -export([ntoa/1, dots/1]).
@@ -456,17 +457,15 @@ is_dom2(_) ->
 
 
 %%
-%% Test ipv4 address or ipv6 address
+%% Parse ipv4 address or ipv6 address
 %% Return {ok, Address} | {error, Reason}
 %%
 address(Cs) when is_list(Cs) ->
     case ipv4_address(Cs) of
-	{ok,IP} -> {ok,IP};
+	{ok,IP} ->
+	    {ok,IP};
 	_ ->
-	    case ipv6_address(Cs) of
-		{ok, IP} -> {ok, IP};
-		Error -> Error
-	    end
+	    ipv6strict_address(Cs)
     end;
 address(_) -> 
     {error, einval}.
@@ -477,49 +476,145 @@ address(_) ->
 %%    d1.d2.d4
 %%    d1.d4
 %%    d4
+%% Any d may be octal, hexadecimal or decimal by C language standards.
+%% d4 fills all LSB bytes. This is legacy behaviour from Solaris
+%% and FreeBSD. And partly Linux that behave the same except
+%% it does not accept hexadecimal.
 %%
 %% Return {ok, IP} | {error, einval}
 %%
 ipv4_address(Cs) ->
-    case catch ipv4_addr(Cs) of
-	{'EXIT',_} -> {error,einval};
-	Addr -> {ok,Addr}
+    try ipv4_addr(Cs) of
+	Addr ->
+	    {ok,Addr}
+    catch
+	error:badarg ->
+	    {error,einval}
     end.
 
-ipv4_addr(Cs) -> 
-    ipv4_addr(d3(Cs), []).
+ipv4_addr(Cs) ->
+    case ipv4_addr(Cs, []) of
+	[D] when D < (1 bsl 32) ->
+	    <<D1,D2,D3,D4>> = <<D:32>>,
+	    {D1,D2,D3,D4};
+	[D,D1] when D < (1 bsl 24), D1 < 256 ->
+	    <<D2,D3,D4>> = <<D:24>>,
+	    {D1,D2,D3,D4};
+	[D,D2,D1] when D < (1 bsl 16), (D2 bor D1) < 256 ->
+	    <<D3,D4>> = <<D:16>>,
+	    {D1,D2,D3,D4};
+	[D4,D3,D2,D1] when (D4 bor D3 bor D2 bor D1) < 256 ->
+	    {D1,D2,D3,D4};
+	_ ->
+	    erlang:error(badarg)
+    end.
 
-ipv4_addr({Cs0,[]}, A) when length(A) =< 3 ->
-    case [tod(Cs0)|A] of
-	[D4,D3,D2,D1] ->
+ipv4_addr([_|_], [_,_,_,_]) ->
+    %% Early bailout for extra characters
+    erlang:error(badarg);
+ipv4_addr("0x"++Cs, Ds) ->
+    ipv4_addr(strip0(Cs), Ds, [], 16, 8);
+ipv4_addr("0X"++Cs, Ds) ->
+    ipv4_addr(strip0(Cs), Ds, [], 16, 8);
+ipv4_addr("0"++Cs, Ds) ->
+    ipv4_addr(strip0(Cs), Ds, [$0], 8, 11);
+ipv4_addr(Cs, Ds) when is_list(Cs) ->
+    ipv4_addr(Cs, Ds, [], 10, 10).
+
+ipv4_addr(Cs0, Ds, Rs, Base, N) ->
+    case ipv4_field(Cs0, N, Rs, Base) of
+	{D,""} ->
+	    [D|Ds];
+	{D,[$.|[_|_]=Cs]} ->
+	    ipv4_addr(Cs, [D|Ds]);
+	{_,_} ->
+	    erlang:error(badarg)
+    end.
+
+strip0("0"++Cs) ->
+    strip0(Cs);
+strip0(Cs) when is_list(Cs) ->
+    Cs.
+
+
+%%
+%% Parse IPv4 strict dotted decimal address, no leading zeros:
+%%    d1.d2.d3.d4
+%%
+%% Return {ok, IP} | {error, einval}
+%%
+ipv4strict_address(Cs) ->
+    try ipv4strict_addr(Cs) of
+	Addr ->
+	    {ok,Addr}
+    catch
+	error:badarg ->
+	    {error,einval}
+    end.
+
+ipv4strict_addr(Cs) ->
+    case ipv4strict_addr(Cs, []) of
+	[D4,D3,D2,D1] when (D4 bor D3 bor D2 bor D1) < 256 ->
 	    {D1,D2,D3,D4};
-	[D4,D2,D1] ->
-	    {D1,D2,0,D4};
-	[D4,D1] ->
-	    {D1,0,0,D4};
-	[D4] ->
-	    {0,0,0,D4}
-    end;
-ipv4_addr({Cs0,"."++Cs1}, A) when length(A) =< 2 ->
-    ipv4_addr(d3(Cs1), [tod(Cs0)|A]).
+	_ ->
+	    erlang:error(badarg)
+    end.
+
+ipv4strict_addr([_|_], [_,_,_,_]) ->
+    %% Early bailout for extra characters
+    erlang:error(badarg);
+ipv4strict_addr("0", Ds) ->
+    [0|Ds];
+ipv4strict_addr("0."++Cs, Ds) ->
+    ipv4strict_addr(Cs, [0|Ds]);
+ipv4strict_addr(Cs0, Ds) when is_list(Cs0) ->
+    case ipv4_field(Cs0, 3, [], 10) of
+	{D,""} ->
+	    [D|Ds];
+	{D,[$.|[_|_]=Cs]} ->
+	    ipv4strict_addr(Cs, [D|Ds]);
+	{_,_} ->
+	    erlang:error(badarg)
+    end.
+
 
-d3(Cs) -> d3(Cs, []).
 
-d3([C|Cs], R) when C >= $0, C =< $9, length(R) =< 2 ->
-    d3(Cs, [C|R]);
-d3(Cs, [_|_]=R) ->
-    {lists:reverse(R),Cs}.
+ipv4_field("", _, Rs, Base) ->
+    {ipv4_field(Rs, Base),""};
+ipv4_field("."++_=Cs, _, Rs, Base) ->
+    {ipv4_field(Rs, Base),Cs};
+ipv4_field("0"++_, _, [], _) ->
+    erlang:error(badarg);
+ipv4_field([C|Cs], N, Rs, Base) when N > 0 ->
+    ipv4_field(Cs, N-1, [C|Rs], Base);
+ipv4_field(Cs, _, _, _) when is_list(Cs) ->
+    erlang:error(badarg).
+
+ipv4_field(Rs, Base) ->
+    V = erlang:list_to_integer(lists:reverse(Rs), Base),
+    if  V < 0 ->
+	    erlang:error(badarg);
+	true ->
+	    V
+    end.
 
-tod(Cs) ->
-    case erlang:list_to_integer(Cs) of
-	D when D >= 0, D =< 255 ->
-	    D;
+
+
+%%
+%% Forgiving IPv6 address
+%%
+%% Accepts IPv4 address and returns it as a IPv4 compatible IPv6 address
+%%
+ipv6_address(Cs) ->
+    case ipv4_address(Cs) of
+	{ok,{D1,D2,D3,D4}} ->
+	    {ok,{0,0,0,0,0,16#ffff,(D1 bsl 8) bor D2,(D3 bsl 8) bor D4}};
 	_ ->
-	    erlang:error(badarg, [Cs])
+	    ipv6strict_address(Cs)
     end.
 
 %%
-%% Parse IPv6 address: 
+%% Parse IPv6 address according to RFC 4291:
 %%     x1:x2:x3:x4:x5:x6:x7:x8
 %%     x1:x2::x7:x8
 %%     ::x7:x8
@@ -530,77 +625,89 @@ tod(Cs) ->
 %%     ::x5:x6:d7a.d7b.d8a.d8b
 %%     x1:x2::d7a.d7b.d8a.d8b
 %%     ::d7a.d7b.d8a.d8b
+%%     etc
 %%
 %% Return {ok, IP} | {error, einval}
 %%
-ipv6_address(Cs) ->
-    case catch ipv6_addr(Cs) of
-	{'EXIT',_} -> {error,einval};
-	Addr -> {ok,Addr}
+ipv6strict_address(Cs) ->
+    try ipv6_addr(Cs) of
+	Addr ->
+	    {ok,Addr}
+    catch
+	error:badarg ->
+	    {error,einval}
     end.
 
 ipv6_addr("::") ->
-    ipv6_addr_done([], []);
+    ipv6_addr_done([], [], 0);
 ipv6_addr("::"++Cs) ->
-    ipv6_addr(x4(Cs), [], []);
+    ipv6_addr(hex(Cs), [], [], 0);
 ipv6_addr(Cs) ->
-    ipv6_addr(x4(Cs), []).
+    ipv6_addr(hex(Cs), [], 0).
 
 %% Before "::"
-ipv6_addr({Cs0,[]}, A) when length(A) =:= 7 ->
-    ipv6_addr_done([tox(Cs0)|A]);
-ipv6_addr({Cs0,"::"}, A) when length(A) =< 6 ->
-    ipv6_addr_done([tox(Cs0)|A], []);
-ipv6_addr({Cs0,"::"++Cs1}, A) when length(A) =< 5 ->
-    ipv6_addr(x4(Cs1), [tox(Cs0)|A], []);
-ipv6_addr({Cs0,":"++Cs1}, A) when length(A) =< 6 ->
-    ipv6_addr(x4(Cs1), [tox(Cs0)|A]);
-ipv6_addr({Cs0,"."++Cs1}, A) when length(A) =:= 6 ->
-    ipv6_addr(d3(Cs1), A, [], [tod(Cs0)]).
+ipv6_addr({Cs0,[]}, A, N) when N == 7 ->
+    ipv6_addr_done([hex_to_int(Cs0)|A]);
+ipv6_addr({Cs0,"::"}, A, N) when N =< 6 ->
+    ipv6_addr_done([hex_to_int(Cs0)|A], [], N+1);
+ipv6_addr({Cs0,"::"++Cs1}, A, N) when N =< 5 ->
+    ipv6_addr(hex(Cs1), [hex_to_int(Cs0)|A], [], N+1);
+ipv6_addr({Cs0,":"++Cs1}, A, N) when N =< 6 ->
+    ipv6_addr(hex(Cs1), [hex_to_int(Cs0)|A], N+1);
+ipv6_addr({Cs0,"."++_=Cs1}, A, N) when N == 6 ->
+    ipv6_addr_done(A, [], N, ipv4strict_addr(Cs0++Cs1));
+ipv6_addr(_, _, _) ->
+    erlang:error(badarg).
 
 %% After "::"
-ipv6_addr({Cs0,[]}, A, B) when length(A)+length(B) =< 6 ->
-    ipv6_addr_done(A, [tox(Cs0)|B]);
-ipv6_addr({Cs0,":"++Cs1}, A, B) when length(A)+length(B) =< 5 ->
-    ipv6_addr(x4(Cs1), A, [tox(Cs0)|B]);
-ipv6_addr({Cs0,"."++Cs1}, A, B) when length(A)+length(B) =< 5 ->
-    ipv6_addr(x4(Cs1), A, B, [tod(Cs0)]).
+ipv6_addr({Cs0,[]}, A, B, N) when N =< 6 ->
+    ipv6_addr_done(A, [hex_to_int(Cs0)|B], N+1);
+ipv6_addr({Cs0,":"++Cs1}, A, B, N) when N =< 5 ->
+    ipv6_addr(hex(Cs1), A, [hex_to_int(Cs0)|B], N+1);
+ipv6_addr({Cs0,"."++_=Cs1}, A, B, N) when N =< 5 ->
+    ipv6_addr_done(A, B, N, ipv4strict_addr(Cs0++Cs1));
+ipv6_addr(_, _, _, _) ->
+    erlang:error(badarg).
 
-%% After "."
-ipv6_addr({Cs0,[]}, A, B, C) when length(C) =:= 3 ->
-    ipv6_addr_done(A, B, [tod(Cs0)|C]);
-ipv6_addr({Cs0,"."++Cs1}, A, B, C) when length(C) =< 2 ->
-    ipv6_addr(d3(Cs1), A, B, [tod(Cs0)|C]).
+ipv6_addr_done(Ar, Br, N, {D1,D2,D3,D4}) ->
+    ipv6_addr_done(Ar, [((D3 bsl 8) bor D4),((D1 bsl 8) bor D2)|Br], N+2).
 
-ipv6_addr_done(Ar, Br, [D4,D3,D2,D1]) ->
-    ipv6_addr_done(Ar, [((D3 bsl 8) bor D4),((D1 bsl 8) bor D2)|Br]).
-
-ipv6_addr_done(Ar, Br) ->
-    ipv6_addr_done(Br++dup(8-length(Ar)-length(Br), 0, Ar)).
+ipv6_addr_done(Ar, Br, N) ->
+    ipv6_addr_done(Br++dup(8-N, 0, Ar)).
 
 ipv6_addr_done(Ar) ->
     list_to_tuple(lists:reverse(Ar)).
 
-x4(Cs) -> x4(Cs, []).
-
-x4([C|Cs], R) when C >= $0, C =< $9, length(R) =< 3 ->
-    x4(Cs, [C|R]);
-x4([C|Cs], R) when C >= $a, C =< $f, length(R) =< 3 ->
-    x4(Cs, [C|R]);
-x4([C|Cs], R) when C >= $A, C =< $F, length(R) =< 3 ->
-    x4(Cs, [C|R]);
-x4(Cs, [_|_]=R) ->
-    {lists:reverse(R),Cs}.
-
-tox(Cs) ->
-    erlang:list_to_integer(Cs, 16).
+%% Collect Hex digits
+hex(Cs) -> hex(Cs, []).
+%%
+hex([C|Cs], R) when C >= $0, C =< $9 ->
+    hex(Cs, [C|R]);
+hex([C|Cs], R) when C >= $a, C =< $f ->
+    hex(Cs, [C|R]);
+hex([C|Cs], R) when C >= $A, C =< $F ->
+    hex(Cs, [C|R]);
+hex(Cs, [_|_]=R) when is_list(Cs) ->
+    {lists:reverse(R),Cs};
+hex(_, _) ->
+    erlang:error(badarg).
+
+%% Hex string to integer
+hex_to_int(Cs0) ->
+    case strip0(Cs0) of
+	Cs when length(Cs) =< 4 ->
+	    erlang:list_to_integer("0"++Cs, 16);
+	_ ->
+	    erlang:error(badarg)
+    end.
 
+%% Dup onto head of existing list
 dup(0, _, L) ->
     L;
 dup(N, E, L) when is_integer(N), N >= 1 ->
-    dup(N-1, E, [E|L]);
-dup(N, E, L) ->
-    erlang:error(badarg, [N,E,L]).
+    dup(N-1, E, [E|L]).
+
+
 
 %% Convert IPv4 adress to ascii
 %% Convert IPv6 / IPV4 adress to ascii (plain format)
@@ -674,7 +781,7 @@ separate(_E, [H], R) ->
     lists:reverse(R, [H]).
 
 %% convert to A.B decimal form
-dig_to_dec(0) -> [$0,$.,$0];
+dig_to_dec(0) -> "0.0";
 dig_to_dec(X) -> 
     integer_to_list((X bsr 8) band 16#ff) ++ "." ++
 	integer_to_list(X band 16#ff).