usr.sbin/in.talkd/in.talkd.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 * Copyright 2002 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T
 * All Rights Reserved.
 */

/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California.
 * All Rights Reserved.
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * Invoked by the Internet daemon to handle talk requests
 * Processes talk requests until MAX_LIFE seconds go by with
 * no action, then dies.
 */

#include <stdio.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/systeminfo.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include "talkd_impl.h"

static CTL_MSG request;
static CTL_RESPONSE response;

char hostname[HOST_NAME_LENGTH];
int debug = 0;

static CTL_MSG swapmsg(CTL_MSG req);

int
main()
{
    struct sockaddr_in from;
    socklen_t from_size = (socklen_t)sizeof (from);
    int cc;
    int name_length = sizeof (hostname);
    fd_set rfds;
    struct timeval tv;

    (void) sysinfo(SI_HOSTNAME, hostname, name_length);

    for (;;) {
        tv.tv_sec = MAX_LIFE;
        tv.tv_usec = 0;
        FD_ZERO(&rfds);
        FD_SET(0, &rfds);
        if (select(1, &rfds, 0, 0, &tv) <= 0)
            return (0);
        cc = recvfrom(0, (char *)&request, sizeof (request), 0,
            (struct sockaddr *)&from, &from_size);

        if (cc != sizeof (request)) {
            if (cc < 0 && errno != EINTR) {
                print_error("receive");
            }
        } else {

            if (debug) {
                (void) printf("Request received : \n");
                (void) print_request(&request);
            }

            request = swapmsg(request);
            process_request(&request, &response);

            if (debug) {
                (void) printf("Response sent : \n");
                print_response(&response);
            }

            /*
             * Can block here, is this what I want?
             */
            cc = sendto(0, (char *)&response, sizeof (response), 0,
                (struct sockaddr *)&request.ctl_addr,
                (socklen_t)sizeof (request.ctl_addr));

            if (cc != sizeof (response)) {
                print_error("Send");
            }
        }
    }
}

void
print_error(char *string)
{
    FILE *cons;
    char *err_dev = "/dev/console";
    char *sys;
    pid_t val, pid;

    if (debug)
        err_dev = "/dev/tty";

    if ((sys = strerror(errno)) == (char *)NULL)
        sys = "Unknown error";

    /* don't ever open tty's directly, let a child do it */
    if ((pid = fork()) == 0) {
        cons = fopen(err_dev, "a");
        if (cons != NULL) {
            (void) fprintf(cons, "Talkd : %s : %s(%d)\n\r", string,
                sys, errno);
            (void) fclose(cons);
        }
        exit(0);
    } else {
        /* wait for the child process to return */
        do {
            val = wait(0);
            if (val == (pid_t)-1) {
                if (errno == EINTR) {
                    continue;
                } else if (errno == ECHILD) {
                    break;
                }
            }
        } while (val != pid);
    }
}

#define swapshort(a) (((a << 8) | ((unsigned short) a >> 8)) & 0xffff)
#define swaplong(a) ((swapshort(a) << 16) | (swapshort(((unsigned)a >> 16))))

/*
 * Heuristic to detect if need to swap bytes.
 */

static CTL_MSG
swapmsg(CTL_MSG req)
{
    CTL_MSG swapreq;

    if (req.ctl_addr.sin_family == swapshort(AF_INET)) {
        swapreq = req;
        swapreq.id_num = swaplong(req.id_num);
        swapreq.pid = swaplong(req.pid);
        swapreq.addr.sin_family = swapshort(req.addr.sin_family);
        swapreq.ctl_addr.sin_family =
            swapshort(req.ctl_addr.sin_family);
        return (swapreq);
    } else {
        return (req);
    }
}