sshによるリモートアクセスを見分ける方法 SSH_CONNECTION SSH_CLIENT

/* $OpenBSD: session.c,v 1.220 2006/10/09 23:36:11 djm Exp $ */

/* 省略 */

static int
auth_input_request_forwarding(struct passwd * pw)
{
	Channel *nc;
	int sock;
	struct sockaddr_un sunaddr;

	/* 省略 */

	/* SSH_CLIENT deprecated */
	snprintf(buf, sizeof buf, "%.50s %d %d",
	    get_remote_ipaddr(), get_remote_port(), get_local_port());
	child_set_env(&env, &envsize, "SSH_CLIENT", buf);

	laddr = get_local_ipaddr(packet_get_connection_in());
	snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
	    get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
	xfree(laddr);
	child_set_env(&env, &envsize, "SSH_CONNECTION", buf);

	if (s->ttyfd != -1)
		child_set_env(&env, &envsize, "SSH_TTY", s->tty);
	if (s->term)
		child_set_env(&env, &envsize, "TERM", s->term);
	if (s->display)
		child_set_env(&env, &envsize, "DISPLAY", s->display);
	if (original_command)
		child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
		    original_command);

	/* 省略 */
}

#!/usr/local/bin/perl -w
use strict;

use Env qw(SSH_CONNECTION SSH_CLIENT);

my $remote = 0;
if(defined $ENV{SSH_CONNECTION} or defined $ENV{SSH_CLIENT} ) {
	$remote = 1;
}

print $remote, "\n";