Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!iuvax!cica!tut.cis.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!snorkelwacker!bloom-beacon!prg.oxford.ac.UK!Mark.Bush
From: Mark.Bush@prg.oxford.ac.UK
Newsgroups: comp.windows.x
Subject: Re: How to get xdm to make wtmp and utmp file entries?
Message-ID: <9006111454.AA13186@uk.ac.oxford.prg.boothp1>
Date: 11 Jun 90 14:54:50 GMT
Sender: root@athena.mit.edu (Wizard A. Root)
Organization: The Internet
Lines: 124

I've had a few requests for my xlogin/xlogout programs so I thought I'd
include them here---I didn't think it was worth posting them to
comp.sources.x.  We have a network of Sun workstations here (no x-terminals
or anything) so I no longer use xdm or these programs to run X sessions but
get users to invoke startx.

WARNING:  These programs assume that the console entry in the utmp file
is the second slot.  I was only using these programs on my machine and I
could guarantee that the first utmp slot was all NULLs and the second was
the console slot.  To make them more general, ttyslot() should be used.  I
think they will only run on Suns as they are (though they may well run on
general BSD4.{2,3} boxes).

DISCLAIMER:  These programs are supplied `as is' and without warranty.  I
accept no responsibility for any problems/errors/faults that may occur due
to their use.

If you want to take these programs and change them and/or distribute them then
feel free.

I wrote these one afternoon as a hack so they are not exactly elegant and I
don't claim that they will always work so, please, no flames.

Share and enjoy,
Mark
-------------------------------------------------------------------------------
/*
 * xlogin.c
 * Mark Bush
 * Mark.Bush@uk.ac.oxford.prg
 */

#include <sys/time.h>
#include <stdio.h>
#include <utmp.h>

main(argc, argv)
int argc;
char *argv[];
{
    char *p;
    FILE *ufp, *wfp;
    struct utmp ut;
    int i, length;

    if ((ufp = fopen("/etc/utmp", "r+")) == NULL ||
        (wfp = fopen("/usr/adm/wtmp", "a")) == NULL)
    {
        perror("Can't log login.");
        exit(1);
    }

    length = strlen(argv[1]);
    length = (length>8 ? 8 : length);

    fseek(ufp, (long)36, 0);    /* Go to second slot */
    p = (char *)&ut;
    for (i=0; i<36; i++)
        *p++ = getc(ufp);
    fseek(ufp, (long)-36, 1);
    sprintf(ut.ut_name, "\0\0\0\0\0\0\0\0");
    for (i=0; i<length; i++)
        ut.ut_name[i] = argv[1][i];
    for (i=length; i<8; i++)
        ut.ut_name[i] = '\0';
    ut.ut_time = time(0);
    sprintf(ut.ut_host, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
    sprintf(ut.ut_line, "console\0");
    p = (char *)&ut;
    for (i=0; i<36; i++)
    {
        putc(*p, ufp);
        putc(*p++, wfp);
    }
    
    fclose(ufp);
    fclose(wfp);
}
-------------------------------------------------------------------------------
/*
 * xlogout.c
 * Mark Bush
 * Mark.Bush@uk.ac.oxford.prg
 */

#include <sys/time.h>
#include <stdio.h>
#include <utmp.h>

main(argc, argv)
int argc;
char *argv[];
{
    char *p;
    FILE *ufp, *wfp;
    struct utmp ut;
    int i;

    if ((ufp = fopen("/etc/utmp", "r+")) == NULL ||
        (wfp = fopen("/usr/adm/wtmp", "a")) == NULL)
    {
        perror("Can't log logout.");
        exit(1);
    }

    fseek(ufp, (long)36, 0);    /* Go to second slot */
    p = (char *)&ut;
    for (i=0; i<36; i++)
        *p++ = getc(ufp);
    fseek(ufp, (long)-36, 1);
    sprintf(ut.ut_name, "\0\0\0\0\0\0\0\0");
    ut.ut_time = time(0);
    sprintf(ut.ut_host, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
    p = (char *)&ut;
    for (i=0; i<36; i++)
    {
        putc('\0', ufp);
        putc(*p++, wfp);
    }

    fclose(ufp);
    fclose(wfp);
}
-------------------------------------------------------------------------------