1/* Part of SWI-Prolog 2 3 Author: Jan Wielemaker & Steve Prior 4 E-mail: jan@swi-prolog.org 5 WWW: https://www.swi-prolog.org 6 Copyright (c) 2004-2026, University of Amsterdam 7 VU University Amsterdam 8 CWI, Amsterdam 9 SWI-Prolog Solutions b.v. 10 All rights reserved. 11 12 Redistribution and use in source and binary forms, with or without 13 modification, are permitted provided that the following conditions 14 are met: 15 16 1. Redistributions of source code must retain the above copyright 17 notice, this list of conditions and the following disclaimer. 18 19 2. Redistributions in binary form must reproduce the above copyright 20 notice, this list of conditions and the following disclaimer in 21 the documentation and/or other materials provided with the 22 distribution. 23 24 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 25 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 26 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 27 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 28 COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 29 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 30 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 31 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 32 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 34 ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 POSSIBILITY OF SUCH DAMAGE. 36*/ 37 38:- module(prolog_server, 39 [ prolog_server/2 % +Port, +Options 40 ]). 41 42:- autoload(library(option), [option/2]). 43:- autoload(library(socket), 44 [ tcp_socket/1, 45 tcp_setopt/2, 46 tcp_bind/2, 47 tcp_listen/2, 48 tcp_accept/3, 49 tcp_open_socket/3, 50 tcp_host_to_address/2, 51 ip_name/2 52 ]). 53 54 55%! prolog_server(?Port, +Options) 56% 57% Create a TCP/IP based server on the given Port, so you can 58% telnet into Prolog and run an interactive session. This library 59% is intended to provide access for debugging and management of 60% embedded servers. 61% 62% Currently defined options are: 63% 64% - allow(IPOrList) 65% Allow access from IP, a term of the format ip(A,B,C,D), (IPv4) 66% or ip(A, B, C, D, E, F, G, H) (IPv6). Access is granted if the 67% `Peer` address as returned by tcp_accept/3 _unifies_ with 68% IPOrList or, if IPOrList is a list, with a member of this list. 69% If no allow option is provided access is only granted from 70% ip(127,0,0,1) (localhost). <br> 71% __note__ Older versions allowed for repeating this option rather 72% than providing a list. 73% 74% For example: 75% 76% ``` 77% ?- prolog_server(4000, []). 78% 79% % ncat localhost 4000 80% Welcome to the SWI-Prolog server on thread client@127.0.0.1 81% 82% 1 ?- 83% ``` 84% 85% @bug As the connection does not involve a terminal, command 86% history and completion are not provided. Neither are interrupts 87% (Control-C). The Prolog shell can be terminated if `netcat` shuts 88% down the socket on ^D (using the `-N` option). Otherwise one must 89% enter the command "end_of_file." 90% @see The add-on `libssh` provides an embedded SSH server. This 91% provides encryption as well as a _pseudo terminal_, providing 92% full commandline editing, history and interrupt processing. 93 94prolog_server(Port, Options) :- 95 tcp_socket(ServerSocket), 96 tcp_setopt(ServerSocket, reuseaddr), 97 tcp_bind(ServerSocket, Port), 98 tcp_listen(ServerSocket, 5), 99 thread_create(server_loop(ServerSocket, Options), _, 100 [ alias(prolog_server) 101 ]). 102 103server_loop(ServerSocket, Options) :- 104 tcp_accept(ServerSocket, Slave, Peer), 105 tcp_open_socket(Slave, InStream, OutStream), 106 set_stream(InStream, close_on_abort(false)), 107 set_stream(OutStream, close_on_abort(false)), 108 catch(tcp_host_to_address(Host, Peer), 109 error(socket_error(_,_),_), 110 ip_name(Peer, Host)), 111 ( Postfix = [] 112 ; between(2, 1000, Num), 113 Postfix = [-, Num] 114 ), 115 atomic_list_concat(['client@', Host | Postfix], Alias), 116 catch(thread_create( 117 service_client(InStream, OutStream, Peer, Options), 118 _, 119 [ alias(Alias), 120 detached(true) 121 ]), 122 error(permission_error(create, thread, Alias), _), 123 fail), 124 !, 125 server_loop(ServerSocket, Options). 126 127service_client(InStream, OutStream, Peer, Options) :- 128 allow(Peer, Options), 129 !, 130 thread_self(Id), 131 set_prolog_IO(InStream, OutStream, OutStream), 132 set_stream(InStream, tty(true)), 133 set_prolog_flag(tty_control, false), 134 current_prolog_flag(encoding, Enc), 135 set_stream(user_input, encoding(Enc)), 136 set_stream(user_output, encoding(Enc)), 137 set_stream(user_error, encoding(Enc)), 138 set_stream(user_input, newline(detect)), 139 set_stream(user_output, newline(dos)), 140 set_stream(user_error, newline(dos)), 141 format(user_error, 142 'Welcome to the SWI-Prolog server on thread ~w~n~n', 143 [Id]), 144 call_cleanup(prolog, 145 ( close(InStream, [force(true)]), 146 close(OutStream, [force(true)]))). 147service_client(InStream, OutStream, _, _):- 148 thread_self(Id), 149 format(OutStream, 'Go away!!~n', []), 150 close(InStream), 151 close(OutStream), 152 thread_detach(Id). 153 154 155allow(Peer, Options) :- 156 ( option(allow(Allow), Options) 157 -> ( is_list(Allow) 158 -> memberchk(Peer, Allow) 159 ; Peer = Allow 160 ) 161 ; Peer = ip(127,0,0,1) 162 )