/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1983, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/uio.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/socket.h>

#include <protocols/talkd.h>

#include <errno.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <vis.h>

#include "ttymsg.h"
#include "extern.h"

/*
 * Announce an invitation to talk.
 */

/*
 * See if the user is accepting messages. If so, announce that
 * a talk is requested.
 */
int
announce(CTL_MSG *request, const char *remote_machine)
{
        char full_tty[32];
        struct stat stbuf;

        (void)snprintf(full_tty, sizeof(full_tty),
            "%s%s", _PATH_DEV, request->r_tty);
        if (stat(full_tty, &stbuf) < 0 || (stbuf.st_mode&020) == 0)
                return (PERMISSION_DENIED);
        return (print_mesg(request->r_tty, request, remote_machine));
}

#define max(a,b) ( (a) > (b) ? (a) : (b) )
#define N_LINES 5
#define N_CHARS 256

/*
 * Build a block of characters containing the message.
 * It is sent blank filled and in a single block to
 * try to keep the message in one piece if the recipient
 * in vi at the time
 */
int
print_mesg(const char *tty, CTL_MSG *request,
    const char *remote_machine)
{
        struct timeval now;
        time_t clock_sec;
        struct tm *localclock;
        struct iovec iovec;
        char line_buf[N_LINES][N_CHARS];
        int sizes[N_LINES];
        char big_buf[N_LINES*N_CHARS];
        char *bptr, *lptr, *vis_user;
        int i, j, max_size;

        i = 0;
        max_size = 0;
        gettimeofday(&now, NULL);
        clock_sec = now.tv_sec;
        localclock = localtime(&clock_sec);
        (void)snprintf(line_buf[i], N_CHARS, " ");
        sizes[i] = strlen(line_buf[i]);
        max_size = max(max_size, sizes[i]);
        i++;
        (void)snprintf(line_buf[i], N_CHARS,
                "Message from Talk_Daemon@%s at %d:%02d on %d/%.2d/%.2d ...",
                hostname, localclock->tm_hour , localclock->tm_min,
                localclock->tm_year + 1900, localclock->tm_mon + 1,
                localclock->tm_mday);
        sizes[i] = strlen(line_buf[i]);
        max_size = max(max_size, sizes[i]);
        i++;

        vis_user = malloc(strlen(request->l_name) * 4 + 1);
        strvis(vis_user, request->l_name, VIS_CSTYLE);
        (void)snprintf(line_buf[i], N_CHARS,
            "talk: connection requested by %s@%s", vis_user, remote_machine);
        sizes[i] = strlen(line_buf[i]);
        max_size = max(max_size, sizes[i]);
        i++;
        (void)snprintf(line_buf[i], N_CHARS, "talk: respond with:  talk %s@%s",
            vis_user, remote_machine);
        sizes[i] = strlen(line_buf[i]);
        max_size = max(max_size, sizes[i]);
        i++;
        (void)snprintf(line_buf[i], N_CHARS, " ");
        sizes[i] = strlen(line_buf[i]);
        max_size = max(max_size, sizes[i]);
        i++;
        bptr = big_buf;
        *bptr++ = '\007'; /* send something to wake them up */
        *bptr++ = '\r'; /* add a \r in case of raw mode */
        *bptr++ = '\n';
        for (i = 0; i < N_LINES; i++) {
                /* copy the line into the big buffer */
                lptr = line_buf[i];
                while (*lptr != '\0')
                        *(bptr++) = *(lptr++);
                /* pad out the rest of the lines with blanks */
                for (j = sizes[i]; j < max_size + 2; j++)
                        *(bptr++) = ' ';
                *(bptr++) = '\r';       /* add a \r in case of raw mode */
                *(bptr++) = '\n';
        }
        *bptr = '\0';
        iovec.iov_base = big_buf;
        iovec.iov_len = bptr - big_buf;
        /*
         * we choose a timeout of RING_WAIT-5 seconds so that we don't
         * stack up processes trying to write messages to a tty
         * that is permanently blocked.
         */
        if (ttymsg(&iovec, 1, tty, RING_WAIT - 5) != NULL)
                return (FAILED);

        return (SUCCESS);
}