announce.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1983, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#ifndef lint
33#if 0
34static char sccsid[] = "@(#)announce.c	8.3 (Berkeley) 4/28/95";
35#endif
36static const char rcsid[] =
37  "$FreeBSD: stable/11/libexec/talkd/announce.c 330897 2018-03-14 03:19:51Z eadler $";
38#endif /* not lint */
39
40#include <sys/types.h>
41#include <sys/uio.h>
42#include <sys/stat.h>
43#include <sys/time.h>
44#include <sys/wait.h>
45#include <sys/socket.h>
46
47#include <protocols/talkd.h>
48
49#include <errno.h>
50#include <paths.h>
51#include <stdio.h>
52#include <stdlib.h>
53#include <string.h>
54#include <syslog.h>
55#include <unistd.h>
56#include <vis.h>
57
58#include "ttymsg.h"
59#include "extern.h"
60
61/*
62 * Announce an invitation to talk.
63 */
64
65/*
66 * See if the user is accepting messages. If so, announce that
67 * a talk is requested.
68 */
69int
70announce(CTL_MSG *request, const char *remote_machine)
71{
72	char full_tty[32];
73	struct stat stbuf;
74
75	(void)snprintf(full_tty, sizeof(full_tty),
76	    "%s%s", _PATH_DEV, request->r_tty);
77	if (stat(full_tty, &stbuf) < 0 || (stbuf.st_mode&020) == 0)
78		return (PERMISSION_DENIED);
79	return (print_mesg(request->r_tty, request, remote_machine));
80}
81
82#define max(a,b) ( (a) > (b) ? (a) : (b) )
83#define N_LINES 5
84#define N_CHARS 256
85
86/*
87 * Build a block of characters containing the message.
88 * It is sent blank filled and in a single block to
89 * try to keep the message in one piece if the recipient
90 * in vi at the time
91 */
92int
93print_mesg(const char *tty, CTL_MSG *request,
94    const char *remote_machine)
95{
96	struct timeval now;
97	time_t clock_sec;
98	struct tm *localclock;
99	struct iovec iovec;
100	char line_buf[N_LINES][N_CHARS];
101	int sizes[N_LINES];
102	char big_buf[N_LINES*N_CHARS];
103	char *bptr, *lptr, *vis_user;
104	int i, j, max_size;
105
106	i = 0;
107	max_size = 0;
108	gettimeofday(&now, NULL);
109	clock_sec = now.tv_sec;
110	localclock = localtime(&clock_sec);
111	(void)snprintf(line_buf[i], N_CHARS, " ");
112	sizes[i] = strlen(line_buf[i]);
113	max_size = max(max_size, sizes[i]);
114	i++;
115	(void)snprintf(line_buf[i], N_CHARS,
116		"Message from Talk_Daemon@%s at %d:%02d on %d/%.2d/%.2d ...",
117		hostname, localclock->tm_hour , localclock->tm_min,
118		localclock->tm_year + 1900, localclock->tm_mon + 1,
119		localclock->tm_mday);
120	sizes[i] = strlen(line_buf[i]);
121	max_size = max(max_size, sizes[i]);
122	i++;
123
124	vis_user = malloc(strlen(request->l_name) * 4 + 1);
125	strvis(vis_user, request->l_name, VIS_CSTYLE);
126	(void)snprintf(line_buf[i], N_CHARS,
127	    "talk: connection requested by %s@%s", vis_user, remote_machine);
128	sizes[i] = strlen(line_buf[i]);
129	max_size = max(max_size, sizes[i]);
130	i++;
131	(void)snprintf(line_buf[i], N_CHARS, "talk: respond with:  talk %s@%s",
132	    vis_user, remote_machine);
133	sizes[i] = strlen(line_buf[i]);
134	max_size = max(max_size, sizes[i]);
135	i++;
136	(void)snprintf(line_buf[i], N_CHARS, " ");
137	sizes[i] = strlen(line_buf[i]);
138	max_size = max(max_size, sizes[i]);
139	i++;
140	bptr = big_buf;
141	*bptr++ = '\007'; /* send something to wake them up */
142	*bptr++ = '\r';	/* add a \r in case of raw mode */
143	*bptr++ = '\n';
144	for (i = 0; i < N_LINES; i++) {
145		/* copy the line into the big buffer */
146		lptr = line_buf[i];
147		while (*lptr != '\0')
148			*(bptr++) = *(lptr++);
149		/* pad out the rest of the lines with blanks */
150		for (j = sizes[i]; j < max_size + 2; j++)
151			*(bptr++) = ' ';
152		*(bptr++) = '\r';	/* add a \r in case of raw mode */
153		*(bptr++) = '\n';
154	}
155	*bptr = '\0';
156	iovec.iov_base = big_buf;
157	iovec.iov_len = bptr - big_buf;
158	/*
159	 * we choose a timeout of RING_WAIT-5 seconds so that we don't
160	 * stack up processes trying to write messages to a tty
161	 * that is permanently blocked.
162	 */
163	if (ttymsg(&iovec, 1, tty, RING_WAIT - 5) != NULL)
164		return (FAILED);
165
166	return (SUCCESS);
167}
168