Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sdd.hp.com!hp-pcd!hpfcso!hpfcbig!jww
From: jww@hpfcbig.SDE.HP.COM (Jim Wichelman)
Newsgroups: comp.sys.hp
Subject: Re: determining original host
Message-ID: <7540066@hpfcbig.SDE.HP.COM>
Date: 1 Apr 91 18:09:10 GMT
References: <1970@news.tcs.com>
Organization: HP SESD, Fort Collins, CO
Lines: 103


The following simple program should work ...

Jim Wichelman
Hewlett Packard
jww@hpfclp.sde.hp.com


#-------------------------------------------------------------
# This is a shell archive.  Remove anything before this line,
# then unpack it by saving it in a file and typing "sh file".
#
# Wrapped by Jim Wichelman <jww@hpfcjww> on Mon Apr  1 11:07:24 1991
#
# This archive contains:
#	fromhost.c	
#

LANG=""; export LANG
PATH=/bin:/usr/bin:$PATH; export PATH

echo x - fromhost.c
cat >fromhost.c <<'@EOF'
#include <stdio.h>
#include <string.h>
#ifdef hpux
#include <sys/types.h>
#endif
#ifdef apollo
#include <sys/types.h>
#endif
#include <utmp.h>


#define UTMP_FILE "/etc/utmp"

main ()
{
    char 	*tty;
    char	*p;
    FILE 	*fd;
    struct utmp	info;
    char        host[100];
        
    extern char *ttyname();
        

    tty = ttyname( fileno(stderr) );
    if (!tty)
       tty = ttyname( fileno(stdout) );
    if (!tty)
       tty = ttyname( fileno(stdin) );

    tty += strlen("/dev/");
    

    if (!(fd = fopen(UTMP_FILE, "r")))
    {
	printf("unknown-host,  can't open %s\n", UTMP_FILE);
	close(fd);
	exit(1);
    }
    
    while ( fread( (char *)&info, sizeof(info), 1, fd) )
	if (strcmp(tty, info.ut_line) == 0)
	{
	    p = info.ut_host;
            while (*p == ' ') p++;
	    
	    while (*p)
	    {
		if ( ( *p == '.') || (*p == ':') )
		    *p = 0;
	        else
		    p++;
	    }

	    p = info.ut_host;
	    if ( (strlen(p) == 0) || (strcmp("unix", p) == 0))
	    {
		host[0] = 0;
		if (gethostname(host, sizeof(host)) == 0)
		    p = host;
		else
		    p = "<unknown from host>";
	    }
	    	    
	    printf("%s\n",p);
	    close(fd);
	    exit(0);
	}
    
    printf("unknown-host,  no entry in %s\n", UTMP_FILE);
    close(fd);
    exit(1);
}


@EOF

chmod 664 fromhost.c

exit 0