wall.c revision 223940 
1/*
2 * Copyright (c) 1988, 1990, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31
32__FBSDID("$FreeBSD: head/usr.bin/wall/wall.c 223940 2011-07-12 00:31:11Z obrien $");
33
34#ifndef lint
35static const char copyright[] =
36"@(#) Copyright (c) 1988, 1990, 1993\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif
39
40#ifndef lint
41static const char sccsid[] = "@(#)wall.c	8.2 (Berkeley) 11/16/93";
42#endif
43
44/*
45 * This program is not related to David Wall, whose Stanford Ph.D. thesis
46 * is entitled "Mechanisms for Broadcast and Selective Broadcast".
47 */
48
49#include <sys/param.h>
50#include <sys/stat.h>
51#include <sys/uio.h>
52
53#include <ctype.h>
54#include <err.h>
55#include <grp.h>
56#include <locale.h>
57#include <paths.h>
58#include <pwd.h>
59#include <stdio.h>
60#include <stdlib.h>
61#include <string.h>
62#include <time.h>
63#include <unistd.h>
64#include <utmpx.h>
65
66#include "ttymsg.h"
67
68static void makemsg(char *);
69static void usage(void);
70
71struct wallgroup {
72	struct wallgroup *next;
73	char		*name;
74	gid_t		gid;
75} *grouplist;
76int nobanner;
77int mbufsize;
78char *mbuf;
79
80static int
81ttystat(char *line)
82{
83	struct stat sb;
84	char ttybuf[MAXPATHLEN];
85
86	(void)snprintf(ttybuf, sizeof(ttybuf), "%s%s", _PATH_DEV, line);
87	if (stat(ttybuf, &sb) == 0) {
88		return (0);
89	} else
90		return (-1);
91}
92
93int
94main(int argc, char *argv[])
95{
96	struct iovec iov;
97	struct utmpx *utmp;
98	int ch;
99	int ingroup;
100	struct wallgroup *g;
101	struct group *grp;
102	char **np;
103	const char *p;
104	struct passwd *pw;
105
106	(void)setlocale(LC_CTYPE, "");
107
108	while ((ch = getopt(argc, argv, "g:n")) != -1)
109		switch (ch) {
110		case 'n':
111			/* undoc option for shutdown: suppress banner */
112			if (geteuid() == 0)
113				nobanner = 1;
114			break;
115		case 'g':
116			g = (struct wallgroup *)malloc(sizeof *g);
117			g->next = grouplist;
118			g->name = optarg;
119			g->gid = -1;
120			grouplist = g;
121			break;
122		case '?':
123		default:
124			usage();
125		}
126	argc -= optind;
127	argv += optind;
128	if (argc > 1)
129		usage();
130
131	for (g = grouplist; g; g = g->next) {
132		grp = getgrnam(g->name);
133		if (grp != NULL)
134			g->gid = grp->gr_gid;
135		else
136			warnx("%s: no such group", g->name);
137	}
138
139	makemsg(*argv);
140
141	iov.iov_base = mbuf;
142	iov.iov_len = mbufsize;
143	/* NOSTRICT */
144	while ((utmp = getutxent()) != NULL) {
145		if (utmp->ut_type != USER_PROCESS)
146			continue;
147		if (ttystat(utmp->ut_line) != 0)
148			continue;
149		if (grouplist) {
150			ingroup = 0;
151			pw = getpwnam(utmp->ut_user);
152			if (!pw)
153				continue;
154			for (g = grouplist; g && ingroup == 0; g = g->next) {
155				if (g->gid == (gid_t)-1)
156					continue;
157				if (g->gid == pw->pw_gid)
158					ingroup = 1;
159				else if ((grp = getgrgid(g->gid)) != NULL) {
160					for (np = grp->gr_mem; *np; np++) {
161						if (strcmp(*np, utmp->ut_user) == 0) {
162							ingroup = 1;
163							break;
164						}
165					}
166				}
167			}
168			if (ingroup == 0)
169				continue;
170		}
171		if ((p = ttymsg(&iov, 1, utmp->ut_line, 60*5)) != NULL)
172			warnx("%s", p);
173	}
174	exit(0);
175}
176
177static void
178usage(void)
179{
180	(void)fprintf(stderr, "usage: wall [-g group] [file]\n");
181	exit(1);
182}
183
184void
185makemsg(char *fname)
186{
187	int cnt;
188	unsigned char ch;
189	struct tm *lt;
190	struct passwd *pw;
191	struct stat sbuf;
192	time_t now;
193	FILE *fp;
194	int fd;
195	char *p, hostname[MAXHOSTNAMELEN], lbuf[256], tmpname[64];
196	const char *tty;
197	const char *whom;
198	gid_t egid;
199
200	(void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
201	if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
202		err(1, "can't open temporary file");
203	(void)unlink(tmpname);
204
205	if (!nobanner) {
206		tty = ttyname(STDERR_FILENO);
207		if (tty == NULL)
208			tty = "no tty";
209
210		if (!(whom = getlogin()))
211			whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
212		(void)gethostname(hostname, sizeof(hostname));
213		(void)time(&now);
214		lt = localtime(&now);
215
216		/*
217		 * all this stuff is to blank out a square for the message;
218		 * we wrap message lines at column 79, not 80, because some
219		 * terminals wrap after 79, some do not, and we can't tell.
220		 * Which means that we may leave a non-blank character
221		 * in column 80, but that can't be helped.
222		 */
223		(void)fprintf(fp, "\r%79s\r\n", " ");
224		(void)snprintf(lbuf, sizeof(lbuf),
225		    "Broadcast Message from %s@%s",
226		    whom, hostname);
227		(void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
228		(void)snprintf(lbuf, sizeof(lbuf),
229		    "        (%s) at %d:%02d %s...", tty,
230		    lt->tm_hour, lt->tm_min, lt->tm_zone);
231		(void)fprintf(fp, "%-79.79s\r\n", lbuf);
232	}
233	(void)fprintf(fp, "%79s\r\n", " ");
234
235	if (fname) {
236		egid = getegid();
237		setegid(getgid());
238	       	if (freopen(fname, "r", stdin) == NULL)
239			err(1, "can't read %s", fname);
240		setegid(egid);
241	}
242	cnt = 0;
243	while (fgets(lbuf, sizeof(lbuf), stdin)) {
244		for (p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
245			if (ch == '\r') {
246				putc('\r', fp);
247				cnt = 0;
248				continue;
249			} else if (ch == '\n') {
250				for (; cnt < 79; ++cnt)
251					putc(' ', fp);
252				putc('\r', fp);
253				putc('\n', fp);
254				break;
255			}
256			if (cnt == 79) {
257				putc('\r', fp);
258				putc('\n', fp);
259				cnt = 0;
260			}
261			if (((ch & 0x80) && ch < 0xA0) ||
262				   /* disable upper controls */
263				   (!isprint(ch) && !isspace(ch) &&
264				    ch != '\a' && ch != '\b')
265				  ) {
266				if (ch & 0x80) {
267					ch &= 0x7F;
268					putc('M', fp);
269					if (++cnt == 79) {
270						putc('\r', fp);
271						putc('\n', fp);
272						cnt = 0;
273					}
274					putc('-', fp);
275					if (++cnt == 79) {
276						putc('\r', fp);
277						putc('\n', fp);
278						cnt = 0;
279					}
280				}
281				if (iscntrl(ch)) {
282					ch ^= 040;
283					putc('^', fp);
284					if (++cnt == 79) {
285						putc('\r', fp);
286						putc('\n', fp);
287						cnt = 0;
288					}
289				}
290			}
291			putc(ch, fp);
292		}
293	}
294	(void)fprintf(fp, "%79s\r\n", " ");
295	rewind(fp);
296
297	if (fstat(fd, &sbuf))
298		err(1, "can't stat temporary file");
299	mbufsize = sbuf.st_size;
300	if (!(mbuf = malloc((u_int)mbufsize)))
301		err(1, "out of memory");
302	if ((int)fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
303		err(1, "can't read temporary file");
304	(void)close(fd);
305}
306