usr/src/etc/talkd/talkd.c

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1983 Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)talkd.c     5.4 (Berkeley) 6/18/88";
#endif /* not lint */

/*
 * The top level of the daemon, the format is heavily borrowed
 * from rwhod.c. Basically: find out who and where you are;
 * disconnect all descriptors and ttys, and then endless
 * loop on waiting for and processing requests
 */
#include <stdio.h>
#include <errno.h>
#include <signal.h>
#include <syslog.h>

#include <protocols/talkd.h>

CTL_MSG         request;
CTL_RESPONSE    response;

int     sockt;
int     debug = 0;
int     timeout();
long    lastmsgtime;

char    hostname[32];

#define TIMEOUT 30
#define MAXIDLE 120

main(argc, argv)
        int argc;
        char *argv[];
{
        register CTL_MSG *mp = &request;
        int cc;

        if (getuid()) {
                fprintf(stderr, "%s: getuid: not super-user", argv[0]);
                exit(1);
        }
        openlog("talkd", LOG_PID, LOG_DAEMON);
        if (gethostname(hostname, sizeof (hostname) - 1) < 0) {
                syslog(LOG_ERR, "gethostname: %m");
                _exit(1);
        }
        if (chdir("/dev") < 0) {
                syslog(LOG_ERR, "chdir: /dev: %m");
                _exit(1);
        }
        if (argc > 1 && strcmp(argv[1], "-d") == 0)
                debug = 1;
        signal(SIGALRM, timeout);
        alarm(TIMEOUT);
        for (;;) {
                extern int errno;

                cc = recv(0, (char *)mp, sizeof (*mp), 0);
                if (cc != sizeof (*mp)) {
                        if (cc < 0 && errno != EINTR)
                                syslog(LOG_WARNING, "recv: %m");
                        continue;
                }
                lastmsgtime = time(0);
                process_request(mp, &response);
                /* can block here, is this what I want? */
                cc = sendto(sockt, (char *)&response,
                    sizeof (response), 0, &mp->ctl_addr, sizeof (mp->ctl_addr));
                if (cc != sizeof (response))
                        syslog(LOG_WARNING, "sendto: %m");
        }
}

timeout()
{

        if (time(0) - lastmsgtime >= MAXIDLE)
                _exit(0);
        alarm(TIMEOUT);
}