src/libexec/talkd/announce.c

/*	$OpenBSD: announce.c,v 1.26 2024/04/28 16:42:53 florian Exp $	*/

/*
 * Copyright (c) 1983 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/stat.h>
#include <protocols/talkd.h>

#include <limits.h>
#include <paths.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <vis.h>

#include "talkd.h"

static void	print_mesg(FILE *,CTL_MSG *,char *);

/*
 * Announce an invitation to talk.  If the user is
 * accepting messages, announce that a talk is requested.
 */
int
announce(CTL_MSG *request, char *remote_machine)
{
	char full_tty[PATH_MAX];
	FILE *tf;
	struct stat stbuf;

	(void)snprintf(full_tty, sizeof(full_tty), "%s/%s", _PATH_DEV,
	    request->r_tty);
	if (access(full_tty, 0) != 0)
		return (FAILED);
	if ((tf = fopen(full_tty, "w")) == NULL)
		return (PERMISSION_DENIED);
	if (fstat(fileno(tf), &stbuf) == -1) {
		fclose(tf);
		return (PERMISSION_DENIED);
	}
	if ((stbuf.st_mode & S_IWGRP) == 0) {
		fclose(tf);
		return (PERMISSION_DENIED);
	}
	print_mesg(tf, request, remote_machine);
	fclose(tf);
	return (SUCCESS);
}

#define max(a,b) ( (a) > (b) ? (a) : (b) )
#define N_LINES 5
#define N_CHARS 120

/*
 * 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
 * is in vi at the time
 */
static void
print_mesg(FILE *tf, CTL_MSG *request, char *remote_machine)
{
	time_t clocktime;
	struct tm *localclock;
	char line_buf[N_LINES][N_CHARS];
	int sizes[N_LINES];
	char big_buf[(N_LINES + 1) * N_CHARS];
	char *bptr, *lptr, vis_user[sizeof(request->l_name) * 4];
	int i, j, max_size;

	i = 0;
	max_size = 0;
	time(&clocktime);
	localclock = localtime(&clocktime);
	(void)snprintf(line_buf[i], N_CHARS, " ");
	sizes[i] = strlen(line_buf[i]);
	max_size = max(max_size, sizes[i]);
	i++;
	if (localclock) {
		(void)snprintf(line_buf[i], N_CHARS,
		    "Message from Talk_Daemon@%s at %d:%02d ...",
		    hostname, localclock->tm_hour , localclock->tm_min );
	} else {
		(void)snprintf(line_buf[i], N_CHARS,
		    "Message from Talk_Daemon@%s ...", hostname);
	}
	sizes[i] = strlen(line_buf[i]);
	max_size = max(max_size, sizes[i]);
	i++;
	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';
	fprintf(tf, "%s", big_buf);
	fflush(tf);
}