From 34f853950685e4e7ab38f30fc3f17a6beac13349 Mon Sep 17 00:00:00 2001 From: Magnus Henoch Date: Wed, 20 Apr 2016 14:40:39 +0100 Subject: Add -start_epmd command line option Add a command line option that lets you disable automatic starting of epmd when starting a distributed node. This differs from the undocumented setting -no_epmd, in that it does not affect the starting of an erl_epmd process within erl_distribution: the newly started node will expect an epmd instance to have been started previously. --- erts/doc/src/erl.xml | 18 +++++++++++++++++- erts/etc/common/erlexec.c | 21 ++++++++++++++++++++- 2 files changed, 37 insertions(+), 2 deletions(-) diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml index 1bbde7f1e0..e63928ddb0 100644 --- a/erts/doc/src/erl.xml +++ b/erts/doc/src/erl.xml @@ -338,7 +338,8 @@ net_kernel(3). It is also ensured that runs on the current host before Erlang is started. See - epmd(1).

+ epmd(1) and the + -start_epmd option.

The name of the node will be , where is the fully qualified host name of the current host. For short names, use the flag instead.

@@ -463,6 +464,21 @@ flag and those running with the flag, as node names must be unique in distributed Erlang systems.

+ -start_epmd true | false + + +

Specifies whether Erlang should start + epmd on startup. By default + this is true, but if you prefer to start epmd + manually, set this to false.

+ +

This only applies if Erlang is started as a distributed node, + i.e. if -name or -sname is specified. Otherwise, + epmd is not started even if -start_epmd true is given.

+ +

Note that a distributed node will fail to start if epmd is + not running.

+

-smp enable and -smp starts the Erlang runtime diff --git a/erts/etc/common/erlexec.c b/erts/etc/common/erlexec.c index 42da05b1f7..2b2e0e480a 100644 --- a/erts/etc/common/erlexec.c +++ b/erts/etc/common/erlexec.c @@ -195,6 +195,7 @@ static char *plusz_val_switches[] = { #endif void usage(const char *switchname); +static void usage_format(char *format, ...); void start_epmd(char *epmd); void error(char* format, ...); @@ -795,6 +796,24 @@ int main(int argc, char **argv) get_start_erl_data((char *) NULL); } #endif + else if (strcmp(argv[i], "-start_epmd") == 0) { + if (i+1 >= argc) + usage("-start_epmd"); + + if (strcmp(argv[i+1], "true") == 0) { + /* The default */ + no_epmd = 0; + } + else if (strcmp(argv[i+1], "false") == 0) { + no_epmd = 1; + } + else + usage_format("Expected boolean argument for \'-start_epmd\'.\n"); + + add_arg(argv[i]); + add_arg(argv[i+1]); + i++; + } else add_arg(argv[i]); @@ -1173,7 +1192,7 @@ usage_aux(void) "]" #endif "] " - "[-make] [-man [manopts] MANPAGE] [-x] [-emu_args] " + "[-make] [-man [manopts] MANPAGE] [-x] [-emu_args] [-start_epmd BOOLEAN] " "[-args_file FILENAME] [+A THREADS] [+a SIZE] [+B[c|d|i]] [+c [BOOLEAN]] " "[+C MODE] [+h HEAP_SIZE_OPTION] [+K BOOLEAN] " "[+l] [+M ] [+P MAX_PROCS] [+Q MAX_PORTS] " -- cgit v1.2.3 From 252c60632664fdf54395d54ad8d7b7e9e6e74cca Mon Sep 17 00:00:00 2001 From: Magnus Henoch Date: Wed, 20 Apr 2016 17:20:05 +0100 Subject: Use the -epmd_module flag consistently If the -epmd_module flag has been specified on the command line, use that module to register and look up node names instead of the default, erl_epmd. Also document this option. --- erts/doc/src/init.xml | 5 +++++ lib/kernel/src/inet_tcp_dist.erl | 6 ++++-- lib/kernel/src/net_adm.erl | 3 ++- lib/ssl/src/inet_tls_dist.erl | 3 ++- lib/ssl/src/ssl_tls_dist_proxy.erl | 3 ++- 5 files changed, 15 insertions(+), 5 deletions(-) diff --git a/erts/doc/src/init.xml b/erts/doc/src/init.xml index 84a5aea335..878a33c9ca 100644 --- a/erts/doc/src/init.xml +++ b/erts/doc/src/init.xml @@ -241,6 +241,11 @@ marker="kernel:code">code(3).

 + -epmd_module Module + +

Specifies the module to use for registration and lookup of + node names. Defaults to erl_epmd.

+ -eval Expr

Scans, parses and evaluates an arbitrary expression diff --git a/lib/kernel/src/inet_tcp_dist.erl b/lib/kernel/src/inet_tcp_dist.erl index 64b28bb49b..f91d7ef7c3 100644 --- a/lib/kernel/src/inet_tcp_dist.erl +++ b/lib/kernel/src/inet_tcp_dist.erl @@ -73,7 +73,8 @@ gen_listen(Driver, Name) -> {ok, Socket} -> TcpAddress = get_tcp_address(Driver, Socket), {_,Port} = TcpAddress#net_address.address, - case erl_epmd:register_node(Name, Port) of + ErlEpmd = net_kernel:epmd_module(), + case ErlEpmd:register_node(Name, Port) of {ok, Creation} -> {ok, {Socket, TcpAddress, Creation}}; Error -> @@ -280,7 +281,8 @@ do_setup(Driver, Kernel, Node, Type, MyNode, LongOrShortNames, SetupTime) -> case inet:getaddr(Address, AddressFamily) of {ok, Ip} -> Timer = dist_util:start_timer(SetupTime), - case erl_epmd:port_please(Name, Ip) of + ErlEpmd = net_kernel:epmd_module(), + case ErlEpmd:port_please(Name, Ip) of {port, TcpPort, Version} -> ?trace("port_please(~p) -> version ~p~n", [Node,Version]), diff --git a/lib/kernel/src/net_adm.erl b/lib/kernel/src/net_adm.erl index a38356c224..8ec275b88b 100644 --- a/lib/kernel/src/net_adm.erl +++ b/lib/kernel/src/net_adm.erl @@ -96,7 +96,8 @@ names() -> Reason :: address | file:posix(). names(Hostname) -> - erl_epmd:names(Hostname). + ErlEpmd = net_kernel:epmd_module(), + ErlEpmd:names(Hostname). -spec dns_hostname(Host) -> {ok, Name} | {error, Host} when Host :: atom() | string(), diff --git a/lib/ssl/src/inet_tls_dist.erl b/lib/ssl/src/inet_tls_dist.erl index 3481e89af0..0da4b3587f 100644 --- a/lib/ssl/src/inet_tls_dist.erl +++ b/lib/ssl/src/inet_tls_dist.erl @@ -87,7 +87,8 @@ do_setup(Driver, Kernel, Node, Type, MyNode, LongOrShortNames, SetupTime) -> case inet:getaddr(Address, Driver:family()) of {ok, Ip} -> Timer = dist_util:start_timer(SetupTime), - case erl_epmd:port_please(Name, Ip) of + ErlEpmd = net_kernel:epmd_module(), + case ErlEpmd:port_please(Name, Ip) of {port, TcpPort, Version} -> ?trace("port_please(~p) -> version ~p~n", [Node,Version]), diff --git a/lib/ssl/src/ssl_tls_dist_proxy.erl b/lib/ssl/src/ssl_tls_dist_proxy.erl index 4651687fe6..2e308a15b7 100644 --- a/lib/ssl/src/ssl_tls_dist_proxy.erl +++ b/lib/ssl/src/ssl_tls_dist_proxy.erl @@ -116,7 +116,8 @@ handle_call({listen, Driver, Name}, _From, State) -> {ok, TcpAddress} = get_tcp_address(Socket), {ok, WorldTcpAddress} = get_tcp_address(World), {_,Port} = WorldTcpAddress#net_address.address, - case erl_epmd:register_node(Name, Port) of + ErlEpmd = net_kernel:epmd_module(), + case ErlEpmd:register_node(Name, Port) of {ok, Creation} -> {reply, {ok, {Socket, TcpAddress, Creation}}, State#state{listen={Socket, World}}}; -- cgit v1.2.3 From 8ff06daa90c7c3c599c9e8cbc93fe98c2ed5ebfa Mon Sep 17 00:00:00 2001 From: Magnus Henoch Date: Wed, 25 May 2016 17:35:11 +0100 Subject: Add tests for -start_epmd and -epmd_module options For -start_epmd, check that the node starts properly and that we can ping it. For -epmd_module, start two nodes that can communicate only because we supply the correct port number through a command line argument. --- erts/emulator/test/distribution_SUITE.erl | 69 ++++++++++++++++++++++++++++++- 1 file changed, 67 insertions(+), 2 deletions(-) diff --git a/erts/emulator/test/distribution_SUITE.erl b/erts/emulator/test/distribution_SUITE.erl index d0096fb1bc..26780f6017 100644 --- a/erts/emulator/test/distribution_SUITE.erl +++ b/erts/emulator/test/distribution_SUITE.erl @@ -55,7 +55,8 @@ bad_dist_ext_receive/1, bad_dist_ext_process_info/1, bad_dist_ext_control/1, - bad_dist_ext_connection_id/1]). + bad_dist_ext_connection_id/1, + start_epmd_false/1, epmd_module/1]). %% Internal exports. -export([sender/3, receiver2/2, dummy_waiter/0, dead_process/0, @@ -64,6 +65,9 @@ dist_evil_parallel_receiver/0, sendersender/4, sendersender2/4]). +%% epmd_module exports +-export([start_link/0, register_node/2, port_please/2]). + suite() -> [{ct_hooks,[ts_install_cth]}, {timetrap, {minutes, 4}}]. @@ -76,7 +80,8 @@ all() -> {group, trap_bif}, {group, dist_auto_connect}, dist_parallel_send, atom_roundtrip, unicode_atom_roundtrip, atom_roundtrip_r15b, contended_atom_cache_entry, contended_unicode_atom_cache_entry, - bad_dist_structure, {group, bad_dist_ext}]. + bad_dist_structure, {group, bad_dist_ext}, + start_epmd_false, epmd_module]. groups() -> [{bulk_send, [], [bulk_send_small, bulk_send_big, bulk_send_bigbig]}, @@ -1881,6 +1886,66 @@ dmsg_ext(Term) -> dmsg_bad_atom_cache_ref() -> [$R, 137]. +start_epmd_false(Config) when is_list(Config) -> + %% Start a node with the option -start_epmd false. + {ok, OtherNode} = start_node(start_epmd_false, "-start_epmd false"), + %% We should be able to ping it, as epmd was started by us: + pong = net_adm:ping(OtherNode), + stop_node(OtherNode), + + ok. + +epmd_module(Config) when is_list(Config) -> + %% We need a relay node to test this, since the test node uses the + %% standard epmd module. + Sock1 = start_relay_node(epmd_module_node1, "-epmd_module " ++ ?MODULE_STRING), + Node1 = inet_rpc_nodename(Sock1), + %% Ask what port it's listening on - it won't have registered with + %% epmd. + {ok, {ok, Port1}} = do_inet_rpc(Sock1, application, get_env, [kernel, dist_listen_port]), + + %% Start a second node, passing the port number as a secret + %% argument. + Sock2 = start_relay_node(epmd_module_node2, "-epmd_module " ++ ?MODULE_STRING + ++ " -other_node_port " ++ integer_to_list(Port1)), + Node2 = inet_rpc_nodename(Sock2), + %% Node 1 can't ping node 2 + {ok, pang} = do_inet_rpc(Sock1, net_adm, ping, [Node2]), + {ok, []} = do_inet_rpc(Sock1, erlang, nodes, []), + {ok, []} = do_inet_rpc(Sock2, erlang, nodes, []), + %% But node 2 can ping node 1 + {ok, pong} = do_inet_rpc(Sock2, net_adm, ping, [Node1]), + {ok, [Node2]} = do_inet_rpc(Sock1, erlang, nodes, []), + {ok, [Node1]} = do_inet_rpc(Sock2, erlang, nodes, []), + + stop_relay_node(Sock2), + stop_relay_node(Sock1). + +%% epmd_module functions: + +start_link() -> + ignore. + +register_node(_Name, Port) -> + %% Save the port number we're listening on. + application:set_env(kernel, dist_listen_port, Port), + Creation = rand:uniform(3), + {ok, Creation}. + +port_please(_Name, _Ip) -> + case init:get_argument(other_node_port) of + error -> + %% None specified. Default to 42. + Port = 42, + Version = 5, + {port, Port, Version}; + {ok, [[PortS]]} -> + %% Port number given on command line. + Port = list_to_integer(PortS), + Version = 5, + {port, Port, Version} + end. + %%% Utilities timestamp() -> -- cgit v1.2.3