The R13B03 release.OTP_R13B03

1 files changed, 239 insertions, 0 deletions

diff --git a/lib/kernel/src/net_adm.erl b/lib/kernel/src/net_adm.erl
new file mode 100644
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+++ b/lib/kernel/src/net_adm.erl
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+%%
+%% %CopyrightBegin%
+%% 
+%% Copyright Ericsson AB 1996-2009. 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(net_adm).
+-export([host_file/0,
+	 localhost/0,
+	 names/0, names/1,
+	 ping_list/1,
+	 world/0,world/1,
+	 world_list/1, world_list/2,
+	 dns_hostname/1,
+	 ping/1]).
+
+%%------------------------------------------------------------------------
+
+-type verbosity() :: 'silent' | 'verbose'.
+
+%%------------------------------------------------------------------------
+
+%% Try to read .hosts.erlang file in 
+%% 1. cwd , 2. $HOME 3. init:root_dir() 
+
+-spec host_file() -> [atom()] | {'error',atom() | {integer(),atom(),_}}.
+
+host_file() ->
+    Home = case init:get_argument(home) of
+	       {ok, [[H]]} -> [H];
+	       _ -> []
+	   end,
+    case file:path_consult(["."] ++ Home ++ [code:root_dir()], ".hosts.erlang") of
+	{ok, Hosts, _} -> Hosts;
+	Error -> Error
+    end.
+	
+%% Check whether a node is up or down
+%%  side effect: set up a connection to Node if there not yet is one.
+
+-spec ping(atom()) -> 'pang' | 'pong'.
+
+ping(Node) when is_atom(Node) ->
+    case catch gen:call({net_kernel, Node},
+			'$gen_call',
+			{is_auth, node()},
+			infinity) of
+	{ok, yes} -> pong;
+	_ ->
+	    erlang:disconnect_node(Node),
+	    pang
+    end.
+
+-spec localhost() -> string().
+
+localhost() ->
+    {ok, Host} = inet:gethostname(),
+    case inet_db:res_option(domain) of
+	"" -> Host;
+	Domain -> Host ++ "." ++ Domain
+    end.
+
+
+-spec names() -> {'ok', [{string(), integer()}]} | {'error', _}.
+
+names() ->
+    names(localhost()).
+
+-spec names(atom() | string()) -> {'ok', [{string(), integer()}]} | {'error', _}.
+
+names(Hostname) ->
+    case inet:gethostbyname(Hostname) of
+	{ok, {hostent, _Name, _ , _Af, _Size, [Addr | _]}} ->
+	    erl_epmd:names(Addr);
+	Else ->
+	    Else
+    end.
+
+-spec dns_hostname(atom() | string()) -> 
+			{'ok', string()} | {'error', atom() | string()}.
+
+dns_hostname(Hostname) ->
+    case inet:gethostbyname(Hostname) of
+	{ok,{hostent, Name, _ , _Af, _Size, _Addr}} ->
+	    {ok, Name};
+	_ ->
+	    {error, Hostname}
+    end.
+
+%% A common situation in "life" is to have a configuration file with a list
+%% of nodes, and then at startup, all nodes in the list are ping'ed
+%% this can lead to no end of troubles if two disconnected nodes
+%% simultaneously ping each other.
+%% Use this function in order to do it safely.
+%% It assumes a working global.erl which ensures a fully 
+%% connected network.
+%% Had the erlang runtime system been able to fully cope with 
+%% the possibility of two simultaneous (unix) connects, this function would
+%% merley  be lists:map({net_adm, ping}, [], Nodelist).
+%% It is also assumed, that the same (identical) Nodelist is given to all
+%% nodes which are to perform this call (possibly simultaneously).
+%% Even this code has a flaw, and that is the case where two
+%% nodes simultaneously and without *any* other already 
+%% running nodes execute this code. :-(
+
+-spec ping_list([atom()]) -> [atom()].
+
+ping_list(Nodelist) ->
+    net_kernel:monitor_nodes(true),
+    Sofar = ping_first(Nodelist, nodes()),
+    collect_new(Sofar, Nodelist).
+
+ping_first([], _S) ->
+    [];
+ping_first([Node|Nodes], S) ->
+    case lists:member(Node, S) of
+	true -> [Node | ping_first(Nodes, S)];
+	false ->
+	    case ping(Node) of
+		pong -> [Node];
+		pang -> ping_first(Nodes, S)
+	    end
+    end.
+
+collect_new(Sofar, Nodelist) ->
+    receive
+	{nodeup, Node} ->
+	    case lists:member(Node, Nodelist) of
+		true ->
+		    collect_new(Sofar, Nodelist);
+		false ->
+		    collect_new([Node | Sofar], Nodelist)
+	    end
+    after 3000 ->
+	    net_kernel:monitor_nodes(false),
+	    Sofar
+    end.
+
+%% This function polls a set of hosts according to a file called
+%% .hosts.erlang that need to reside either in the current directory
+%% or in your home directory. (The current directory is tried first.)
+%% world() returns a list of all nodes on the network that can be 
+%% found (including ourselves). Note: the $HOME variable is inspected.
+%%
+%% Added possibility to supply a list of hosts instead of reading
+%% the .hosts.erlang file. 971016 [email protected]
+%% e.g. 
+%% net_adm:world_list(['elrond.du.etx.ericsson.se', 'thorin.du.etx.ericsson.se']). 
+
+-spec world() -> [node()].
+
+world() ->
+    world(silent).
+
+-spec world(verbosity()) -> [node()].
+
+world(Verbose) ->
+    case net_adm:host_file() of
+        {error,R} -> exit({error, R});
+        Hosts -> expand_hosts(Hosts, Verbose)
+    end.
+
+-spec world_list([atom()]) -> [node()].
+
+world_list(Hosts) when is_list(Hosts) ->
+    expand_hosts(Hosts, silent).
+
+-spec world_list([atom()], verbosity()) -> [node()].
+
+world_list(Hosts, Verbose) when is_list(Hosts) ->
+    expand_hosts(Hosts, Verbose).
+
+expand_hosts(Hosts, Verbose) ->
+    lists:flatten(collect_nodes(Hosts, Verbose)).
+
+collect_nodes([], _) -> [];
+collect_nodes([Host|Tail], Verbose) ->
+    case collect_host_nodes(Host, Verbose) of
+        nil ->
+            collect_nodes(Tail, Verbose);
+        L ->
+            [L|collect_nodes(Tail, Verbose)]
+    end.
+
+collect_host_nodes(Host, Verbose) ->
+    case names(Host) of
+	{ok, Namelist} ->
+	    do_ping(Namelist, atom_to_list(Host), Verbose);
+	_ ->
+	    nil
+    end.
+
+do_ping(Names, Host0, Verbose) ->
+    case longshort(Host0) of
+	ignored -> [];
+	Host -> do_ping_1(Names, Host, Verbose)
+    end.
+
+do_ping_1([], _Host, _Verbose) ->
+    [];
+do_ping_1([{Name, _} | Rest], Host, Verbose) ->
+    Node = list_to_atom(Name ++ "@" ++ longshort(Host)),
+    verbose(Verbose, "Pinging ~w -> ", [Node]),
+    Result = ping(Node),
+    verbose(Verbose, "~p\n", [Result]),
+    case Result of
+	pong ->
+	    [Node | do_ping_1(Rest, Host, Verbose)];
+	pang ->
+	    do_ping_1(Rest, Host, Verbose)
+    end.
+
+verbose(verbose, Format, Args) ->
+    io:format(Format, Args);
+verbose(_, _, _) ->
+    ok.
+
+longshort(Host) ->
+    case net_kernel:longnames() of
+	false -> uptodot(Host);
+	true -> Host;
+	ignored -> ignored
+    end.
+
+uptodot([$.|_]) -> [];
+uptodot([])-> [];
+uptodot([H|T]) -> [H|uptodot(T)].