Module Dev - Get a PTY in a cgi

Developers
1

Hello :wave:,

I’m current developing a module and I’m stuck. I wanted to create a cgi page that acts as a pseudo terminal interfacing with a local rcon-client .
Here is what should happen:

  1. Upon opening the page, the executable $rcon{"bin"} should be run and every output should be routed to a <pre> tag, and if the process gets terminated (by any means) output that.
  2. The user is offered a text input and a “send” button to submit a command. (Alternatively the user should be able to write inside the pseudo terminal)
  3. All output should be preserved as long as the user is on the page
  4. The process should be exited when the user leaves the page

Here is what I’ve got so far:

I’ve got the form and will probably use javascript to hook into it, since a POST refreshes the page and the output gets deleted. I’ve seen the proc lib and I’m not sure how to exactly get the pty_process_exec going, basically being stuck at the first step (I tested a little bit with wait_for around, but i’m not sure)

#!/usr/bin/perl
# custom_rcon.cgi
# Webinterface for rcon terminal
require "./paldmin-ui-lib.pl";
require "./paldmin-lib.pl";
require "./rcon-lib.pl";

ReadParse();
ui_print_unbuffered_header($text{"glop_rcon"}, $text{"index_title"}, "");
if (defined $rcon{"msg"}{"content"}) {
    alert_box($rcon{"msg"}{"type"}, "", $rcon{"msg"}{"content"});
    ui_print_footer("", $text{"index_return"});
    exit;
} elsif (!foreign_installed("proc")) {
    alert_box($rcon{"msg"}{"type"}, "", $text{"custom_missing_proc"});
    ui_print_footer("", $text{"index_return"});
    exit;
} elsif (!$rcon{"valid"}) {
    ui_print_footer("", $text{"index_return"});
    exit;
}

collapsible_box("info", $text{"info"}, $text{"custom_info"});

# Command Block
print ui_subheading($text{"glop_rcon_cc"});
print ui_textbox("msg", undef, 40, (!$rcon{"valid"}));
# How to hook the button to syswrite ?
print ui_button(
    $text{"send"},
    "cmd",
    (!$rcon{"valid"}),
    "onClick='alert(\"Test\");'"
);

print $text{"index_broadcast_desc"};
print "<br/><br/>";

foreign_require("proc");
proc::clean_environment();
my ($fh, $fpid) = proc::pty_process_exec($rcon{"bin"}, 0, 0);
proc::reset_environment();

# What exactly goes here?

print "<pre>";
print "FH:".$fh." - PID: ".$fpid."<br/>";
print "</pre>";

ui_print_footer("", $text{"index_return"});

1;

Any help is appreciated :slight_smile:

KR

2

Hello,

You should look into xterm/shellserver.pl file.

1 Like
3

I had a look into it and must admit defeat (for now!). This certainly exceeds my knowledge, but from what i got was:

  • Create a Javascript Websocket between server and page. Websocket is used to send commands and receive the output
  • Append the output to the displayed terminal

I will add it to the roadmap of my module, thanks :slight_smile: