erts: Add {line_delimiter, byte()} option to inet:setopts/2

A new {line_delimiter, byte()} option allows line-oriented TCP-based protocols
to use a custom line delimiting character. It is to be used in conjunction
with {packet, line}.

This option also works with erlang:decode_packet/3 when its first argument
is 'line'.

5 files changed, 35 insertions, 2 deletions

diff --git a/lib/kernel/doc/src/inet.xml b/lib/kernel/doc/src/inet.xml
index e5d7ce048a..e6d418dc58 100644
--- a/lib/kernel/doc/src/inet.xml
+++ b/lib/kernel/doc/src/inet.xml
@@ -981,6 +981,11 @@ setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp
 	    indicated length are accepted and not considered invalid due
 	    to internal buffer limitations.</p>
           </item>
+          <tag><c>{line_delimiter, Char}</c>(TCP/IP sockets)</tag>
+          <item>
+            <p>Sets the line delimiting character for line oriented protocols
+              (<c>line</c>). Default value is <c>$\n</c>.</p>
+          </item>
 
 		  <tag><c>{priority, Priority}</c></tag>
           <item> <p>Set the protocol-defined priority for all packets to be sent
diff --git a/lib/kernel/src/inet.erl b/lib/kernel/src/inet.erl
index da7f04089d..855c6377a3 100644
--- a/lib/kernel/src/inet.erl
+++ b/lib/kernel/src/inet.erl
@@ -671,7 +671,7 @@ stats() ->
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 connect_options() ->
     [tos, priority, reuseaddr, keepalive, linger, sndbuf, recbuf, nodelay,
-     header, active, packet, packet_size, buffer, mode, deliver,
+     header, active, packet, packet_size, buffer, mode, deliver, line_delimiter,
      exit_on_close, high_watermark, low_watermark, high_msgq_watermark,
      low_msgq_watermark, send_timeout, send_timeout_close, delay_send, raw,
      show_econnreset].
@@ -721,6 +721,8 @@ con_opt([Opt | Opts], #connect_opts{} = R, As) ->
         {active,N} when is_integer(N), N < 32768, N >= -32768 ->
             NOpts = lists:keydelete(active, 1, R#connect_opts.opts),
             con_opt(Opts, R#connect_opts { opts = [{active,N}|NOpts] }, As);
+	{line_delimiter,C} when is_integer(C), C >= 0, C =< 255 ->
+	    con_add(line_delimiter, C, R, Opts, As);
 	{Name,Val} when is_atom(Name) -> con_add(Name, Val, R, Opts, As);
 	_ -> {error, badarg}
     end;
diff --git a/lib/kernel/src/inet_int.hrl b/lib/kernel/src/inet_int.hrl
index bfe4c9ec8c..e7c6cf8ae2 100644
--- a/lib/kernel/src/inet_int.hrl
+++ b/lib/kernel/src/inet_int.hrl
@@ -149,6 +149,7 @@
 -define(INET_LOPT_MSGQ_LOWTRMRK,  37).
 -define(INET_LOPT_NETNS,          38).
 -define(INET_LOPT_TCP_SHOW_ECONNRESET, 39).
+-define(INET_LOPT_LINE_DELIM,     40).
 % Specific SCTP options: separate range:
 -define(SCTP_OPT_RTOINFO,	 	100).
 -define(SCTP_OPT_ASSOCINFO,	 	101).
diff --git a/lib/kernel/test/bif_SUITE.erl b/lib/kernel/test/bif_SUITE.erl
index c3840f3d16..dd3010567a 100644
--- a/lib/kernel/test/bif_SUITE.erl
+++ b/lib/kernel/test/bif_SUITE.erl
@@ -33,6 +33,7 @@
 	 spawn_failures/1,
 
 	 run_fun/1,
+     decode_packet_delim/1,
 	 wilderness/1]).
 
 -export([init_per_testcase/2, end_per_testcase/2]).
@@ -516,6 +517,15 @@ fetch_proc_vals(Pid) ->
     {value,{heap_size,HS}} = lists:keysearch(heap_size, 1, PI),
     ?line {Ls, P, FA, HS}.
      
+decode_packet_delim(doc) ->
+    ["Test erlang:packet_delim/3 with {line_delimiter,0} option"];
+decode_packet_delim(suite) ->
+    [];
+decode_packet_delim(Config) when is_list(Config) ->
+    {ok,<<"abc",0>>,<<"efg",0>>} =
+        erlang:decode_packet(line, <<"abc",0,"efg",0>>, [{line_delimiter, 0}]),
+    {more, undefined} = erlang:decode_packet(line, <<"abc",0,"efg",0>>, []).
+
 % This testcase should probably be moved somewhere else
 wilderness(doc) ->
     ["Test that memory allocation command line options affecting the"
diff --git a/lib/kernel/test/gen_tcp_api_SUITE.erl b/lib/kernel/test/gen_tcp_api_SUITE.erl
index a051d504b2..2febb1bd68 100644
--- a/lib/kernel/test/gen_tcp_api_SUITE.erl
+++ b/lib/kernel/test/gen_tcp_api_SUITE.erl
@@ -31,7 +31,7 @@
 	 init_per_testcase/2, end_per_testcase/2,
 	 t_connect_timeout/1, t_accept_timeout/1,
 	 t_connect_bad/1,
-	 t_recv_timeout/1, t_recv_eof/1,
+	 t_recv_timeout/1, t_recv_eof/1, t_recv_delim/1,
 	 t_shutdown_write/1, t_shutdown_both/1, t_shutdown_error/1,
 	 t_shutdown_async/1,
 	 t_fdopen/1, t_fdconnect/1, t_implicit_inet6/1]).
@@ -131,6 +131,21 @@ t_recv_eof(Config) when is_list(Config) ->
     ?line {error, closed} = gen_tcp:recv(Client, 0),
     ok.
 
+t_recv_delim(doc) -> "Test using message delimiter $X";
+t_recv_delim(suite) -> [];
+t_recv_delim(Config) when is_list(Config) ->
+    {ok, L} = gen_tcp:listen(0, []),
+    {ok, Port} = inet:port(L),
+    Opts = [{active,false},{packet,line},{line_delimiter,$X}],
+    {ok, Client} = gen_tcp:connect(localhost, Port, Opts),
+    {ok, A} = gen_tcp:accept(L),
+    ok = gen_tcp:send(A, "abcXefgX"),
+    {ok, "abcX"} = gen_tcp:recv(Client, 0, 0),
+    {ok, "efgX"} = gen_tcp:recv(Client, 0, 0),
+    ok = gen_tcp:close(Client),
+    ok = gen_tcp:close(A),
+    ok.
+
 %%% gen_tcp:shutdown/2
 
 t_shutdown_write(Config) when is_list(Config) ->