wall.c revision 202200 
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 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35
36__FBSDID("$FreeBSD: head/usr.bin/wall/wall.c 202200 2010-01-13 18:09:54Z ed $");
37
38#ifndef lint
39static const char copyright[] =
40"@(#) Copyright (c) 1988, 1990, 1993\n\
41	The Regents of the University of California.  All rights reserved.\n";
42#endif
43
44#ifndef lint
45static const char sccsid[] = "@(#)wall.c	8.2 (Berkeley) 11/16/93";
46#endif
47
48/*
49 * This program is not related to David Wall, whose Stanford Ph.D. thesis
50 * is entitled "Mechanisms for Broadcast and Selective Broadcast".
51 */
52
53#include <sys/param.h>
54#include <sys/stat.h>
55#include <sys/uio.h>
56
57#include <ctype.h>
58#include <err.h>
59#include <grp.h>
60#include <locale.h>
61#include <paths.h>
62#include <pwd.h>
63#include <stdio.h>
64#include <stdlib.h>
65#include <string.h>
66#include <time.h>
67#include <unistd.h>
68#include <utmpx.h>
69
70#include "ttymsg.h"
71
72static void makemsg(char *);
73static void usage(void);
74
75struct wallgroup {
76	struct wallgroup *next;
77	char		*name;
78	gid_t		gid;
79} *grouplist;
80int nobanner;
81int mbufsize;
82char *mbuf;
83
84static int
85ttystat(char *line)
86{
87	struct stat sb;
88	char ttybuf[MAXPATHLEN];
89
90	(void)snprintf(ttybuf, sizeof(ttybuf), "%s%s", _PATH_DEV, line);
91	if (stat(ttybuf, &sb) == 0) {
92		return (0);
93	} else
94		return (-1);
95}
96
97int
98main(int argc, char *argv[])
99{
100	struct iovec iov;
101	struct utmpx *utmp;
102	int ch;
103	int ingroup;
104	struct wallgroup *g;
105	struct group *grp;
106	char **np;
107	const char *p;
108	struct passwd *pw;
109
110	(void)setlocale(LC_CTYPE, "");
111
112	while ((ch = getopt(argc, argv, "g:n")) != -1)
113		switch (ch) {
114		case 'n':
115			/* undoc option for shutdown: suppress banner */
116			if (geteuid() == 0)
117				nobanner = 1;
118			break;
119		case 'g':
120			g = (struct wallgroup *)malloc(sizeof *g);
121			g->next = grouplist;
122			g->name = optarg;
123			g->gid = -1;
124			grouplist = g;
125			break;
126		case '?':
127		default:
128			usage();
129		}
130	argc -= optind;
131	argv += optind;
132	if (argc > 1)
133		usage();
134
135	for (g = grouplist; g; g = g->next) {
136		grp = getgrnam(g->name);
137		if (grp != NULL)
138			g->gid = grp->gr_gid;
139		else
140			warnx("%s: no such group", g->name);
141	}
142
143	makemsg(*argv);
144
145	iov.iov_base = mbuf;
146	iov.iov_len = mbufsize;
147	/* NOSTRICT */
148	while ((utmp = getutxent()) != NULL) {
149		if (utmp->ut_type != USER_PROCESS)
150			continue;
151		if (ttystat(utmp->ut_line) != 0)
152			continue;
153		if (grouplist) {
154			ingroup = 0;
155			pw = getpwnam(utmp->ut_user);
156			if (!pw)
157				continue;
158			for (g = grouplist; g && ingroup == 0; g = g->next) {
159				if (g->gid == (gid_t)-1)
160					continue;
161				if (g->gid == pw->pw_gid)
162					ingroup = 1;
163				else if ((grp = getgrgid(g->gid)) != NULL) {
164					for (np = grp->gr_mem; *np; np++) {
165						if (strcmp(*np, utmp->ut_user) == 0) {
166							ingroup = 1;
167							break;
168						}
169					}
170				}
171			}
172			if (ingroup == 0)
173				continue;
174		}
175		if ((p = ttymsg(&iov, 1, utmp->ut_line, 60*5)) != NULL)
176			warnx("%s", p);
177	}
178	exit(0);
179}
180
181static void
182usage(void)
183{
184	(void)fprintf(stderr, "usage: wall [-g group] [file]\n");
185	exit(1);
186}
187
188void
189makemsg(char *fname)
190{
191	int cnt;
192	unsigned char ch;
193	struct tm *lt;
194	struct passwd *pw;
195	struct stat sbuf;
196	time_t now;
197	FILE *fp;
198	int fd;
199	char *p, hostname[MAXHOSTNAMELEN], lbuf[256], tmpname[64];
200	const char *tty;
201	const char *whom;
202	gid_t egid;
203
204	(void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
205	if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
206		err(1, "can't open temporary file");
207	(void)unlink(tmpname);
208
209	if (!nobanner) {
210		tty = ttyname(STDERR_FILENO);
211		if (tty == NULL)
212			tty = "no tty";
213
214		if (!(whom = getlogin()))
215			whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
216		(void)gethostname(hostname, sizeof(hostname));
217		(void)time(&now);
218		lt = localtime(&now);
219
220		/*
221		 * all this stuff is to blank out a square for the message;
222		 * we wrap message lines at column 79, not 80, because some
223		 * terminals wrap after 79, some do not, and we can't tell.
224		 * Which means that we may leave a non-blank character
225		 * in column 80, but that can't be helped.
226		 */
227		(void)fprintf(fp, "\r%79s\r\n", " ");
228		(void)snprintf(lbuf, sizeof(lbuf),
229		    "Broadcast Message from %s@%s",
230		    whom, hostname);
231		(void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
232		(void)snprintf(lbuf, sizeof(lbuf),
233		    "        (%s) at %d:%02d %s...", tty,
234		    lt->tm_hour, lt->tm_min, lt->tm_zone);
235		(void)fprintf(fp, "%-79.79s\r\n", lbuf);
236	}
237	(void)fprintf(fp, "%79s\r\n", " ");
238
239	if (fname) {
240		egid = getegid();
241		setegid(getgid());
242	       	if (freopen(fname, "r", stdin) == NULL)
243			err(1, "can't read %s", fname);
244		setegid(egid);
245	}
246	while (fgets(lbuf, sizeof(lbuf), stdin)) {
247		for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
248			if (ch == '\r') {
249				putc('\r', fp);
250				cnt = 0;
251				continue;
252			} else if (ch == '\n') {
253				for (; cnt < 79; ++cnt)
254					putc(' ', fp);
255				putc('\r', fp);
256				putc('\n', fp);
257				break;
258			}
259			if (cnt == 79) {
260				putc('\r', fp);
261				putc('\n', fp);
262				cnt = 0;
263			}
264			if (((ch & 0x80) && ch < 0xA0) ||
265				   /* disable upper controls */
266				   (!isprint(ch) && !isspace(ch) &&
267				    ch != '\a' && ch != '\b')
268				  ) {
269				if (ch & 0x80) {
270					ch &= 0x7F;
271					putc('M', fp);
272					if (++cnt == 79) {
273						putc('\r', fp);
274						putc('\n', fp);
275						cnt = 0;
276					}
277					putc('-', fp);
278					if (++cnt == 79) {
279						putc('\r', fp);
280						putc('\n', fp);
281						cnt = 0;
282					}
283				}
284				if (iscntrl(ch)) {
285					ch ^= 040;
286					putc('^', fp);
287					if (++cnt == 79) {
288						putc('\r', fp);
289						putc('\n', fp);
290						cnt = 0;
291					}
292				}
293			}
294			putc(ch, fp);
295		}
296	}
297	(void)fprintf(fp, "%79s\r\n", " ");
298	rewind(fp);
299
300	if (fstat(fd, &sbuf))
301		err(1, "can't stat temporary file");
302	mbufsize = sbuf.st_size;
303	if (!(mbuf = malloc((u_int)mbufsize)))
304		err(1, "out of memory");
305	if ((int)fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
306		err(1, "can't read temporary file");
307	(void)close(fd);
308}
309