/*
 * utmp extender 0.1b, by Krzysztof Rusocki <kszysiu@gmail.com>
 * (c) 2005, GPL v2
 *
 * made especially for the G.I.L.D.R.O. project
 */

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <utmp.h>

#define DEV "/dev/"

#ifndef UTMP_FILE
#warning UTMP_FILE was not defined!
#define UTMP_FILE "/var/run/utmp"
#endif

int main(int ac, char ** av)
{
	char * ssh_tty = getenv("SSH_TTY");
	char * term;
	struct utmp u;
	struct utmp * up;
	char * ruser = getenv("REALUSER");
	int rlen;
	char * beg;
	
	if (!ruser || !ssh_tty || (rlen = strlen(ruser) + 1) <= 1)
		return 1;
	

	utmpname(UTMP_FILE);
	setutent();
	
	term = strstr(ssh_tty, DEV);
	if (term)
		term += strlen(DEV);
	strncpy(u.ut_line, term, UT_LINESIZE);
	
	up = getutline(&u);

	if (!up) {
		fprintf(stderr, "ut entry with line: '%s' not found\n", u.ut_line);
		return 1;
	}

	memcpy(&u, up, sizeof(u));
	setutent(); /* ? */
	
	beg = strchr(u.ut_host, '@');
	if (!beg)
		beg = u.ut_host;
	else
		beg++;
	memmove(u.ut_host + rlen, beg, UT_HOSTSIZE - (beg - u.ut_host));
	memcpy(u.ut_host, ruser, rlen);
	u.ut_host[rlen - 1] = '@';
	pututline(&u);
	endutent();

	return 0;
}