/usr/share/Yap/prolog_server.pl is in yap 6.2.2-6+b2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 | /* $Id$
Part of SWI-Prolog
Author: Jan Wielemaker & Steve Prior
E-mail: wielemak@science.uva.nl
WWW: http://www.swi-prolog.org
Copyright (C): 1985-2007, University of Amsterdam
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
As a special exception, if you link this library with other files,
compiled with a Free Software compiler, to produce an executable, this
library does not by itself cause the resulting executable to be covered
by the GNU General Public License. This exception does not however
invalidate any other reasons why the executable file might be covered by
the GNU General Public License.
*/
:- module(prolog_server,
[ prolog_server/2 % +Port, +Options
]).
:- use_module(library(socket)).
%% prolog_server(?Port, +Options)
%
% Create a TCP/IP based server on the given Port, so you can
% telnet into Prolog and run an interactive session. This library
% is intended to provide access for debugging and management of
% embedded servers.
%
% Currently defined options are:
%
% * allow(IP)
% Allow access from IP, a term of the format ip(A,B,C,D).
% Multiple of such terms can exist and access is granted
% if the peer IP address unifies to one of them. If no
% allow option is provided access is only granted from
% ip(127,0,0,1) (localhost).
%
% For example:
%
% ==
% ?- prolog_server(4000, []).
%
% % telnet localhost 4000
% Welcome to the SWI-Prolog server on thread 3
%
% 1 ?-
% ==
%
% @bug As the connection does not involve a terminal, command history
% and completion are not provided. Neither are interrupts
% (Control-C). To terminate the Prolog shell one must enter the
% command "end_of_file."
prolog_server(Port, Options) :-
tcp_socket(ServerSocket),
tcp_setopt(ServerSocket, reuseaddr),
tcp_bind(ServerSocket, Port),
tcp_listen(ServerSocket, 5),
thread_create(server_loop(ServerSocket, Options), _,
[ alias(prolog_server)
]).
server_loop(ServerSocket, Options) :-
tcp_accept(ServerSocket, Slave, Peer),
tcp_open_socket(Slave, InStream, OutStream),
tcp_host_to_address(Host, Peer),
atom_concat('client@', Host, Alias),
thread_create(service_client(InStream, OutStream, Peer, Options),
_,
[ alias(Alias)
]),
server_loop(ServerSocket, Options).
service_client(InStream, OutStream, Peer, Options) :-
allow(Peer, Options), !,
thread_self(Id),
set_prolog_IO(InStream, OutStream, OutStream),
set_stream(InStream, tty(true)),
format(user_error,
'Welcome to the SWI-Prolog server on thread ~w~n~n',
[Id]),
call_cleanup(run_prolog,
( close(InStream),
close(OutStream),
thread_detach(Id))).
service_client(InStream, OutStream, _, _):-
thread_self(Id),
format(OutStream, 'Go away!!~n', []),
close(InStream),
close(OutStream),
thread_detach(Id).
run_prolog :-
catch(prolog, E,
( print_message(error, E),
% E = error(_, _),
run_prolog)).
allow(Peer, Options) :-
( member(allow(Allow), Options)
*-> Peer = Allow,
!
; Peer = ip(127,0,0,1)
).
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