wall.c revision 111209 
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 111209 2003-02-21 08:46:44Z tjr $");
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 <utmp.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
84int
85main(int argc, char *argv[])
86{
87	struct iovec iov;
88	struct utmp utmp;
89	int ch;
90	int ingroup;
91	FILE *fp;
92	struct wallgroup *g;
93	struct group *grp;
94	char **np;
95	const char *p;
96	struct passwd *pw;
97	char line[sizeof(utmp.ut_line) + 1];
98	char username[sizeof(utmp.ut_name) + 1];
99
100	(void)setlocale(LC_CTYPE, "");
101
102	while ((ch = getopt(argc, argv, "g:n")) != -1)
103		switch (ch) {
104		case 'n':
105			/* undoc option for shutdown: suppress banner */
106			if (geteuid() == 0)
107				nobanner = 1;
108			break;
109		case 'g':
110			g = (struct wallgroup *)malloc(sizeof *g);
111			g->next = grouplist;
112			g->name = optarg;
113			g->gid = -1;
114			grouplist = g;
115			break;
116		case '?':
117		default:
118			usage();
119		}
120	argc -= optind;
121	argv += optind;
122	if (argc > 1)
123		usage();
124
125	for (g = grouplist; g; g = g->next) {
126		grp = getgrnam(g->name);
127		if (grp != NULL)
128			g->gid = grp->gr_gid;
129		else
130			warnx("%s: no such group", g->name);
131	}
132
133	makemsg(*argv);
134
135	if (!(fp = fopen(_PATH_UTMP, "r")))
136		err(1, "cannot read %s", _PATH_UTMP);
137	iov.iov_base = mbuf;
138	iov.iov_len = mbufsize;
139	/* NOSTRICT */
140	while (fread((char *)&utmp, sizeof(utmp), 1, fp) == 1) {
141		if (!utmp.ut_name[0])
142			continue;
143		if (grouplist) {
144			ingroup = 0;
145			strlcpy(username, utmp.ut_name, sizeof(utmp.ut_name));
146			pw = getpwnam(username);
147			if (!pw)
148				continue;
149			for (g = grouplist; g && ingroup == 0; g = g->next) {
150				if (g->gid == (gid_t)-1)
151					continue;
152				if (g->gid == pw->pw_gid)
153					ingroup = 1;
154				else if ((grp = getgrgid(g->gid)) != NULL) {
155					for (np = grp->gr_mem; *np; np++) {
156						if (strcmp(*np, username) == 0) {
157							ingroup = 1;
158							break;
159						}
160					}
161				}
162			}
163			if (ingroup == 0)
164				continue;
165		}
166		strncpy(line, utmp.ut_line, sizeof(utmp.ut_line));
167		line[sizeof(utmp.ut_line)] = '\0';
168		if ((p = ttymsg(&iov, 1, line, 60*5)) != NULL)
169			warnx("%s", p);
170	}
171	exit(0);
172}
173
174static void
175usage()
176{
177	(void)fprintf(stderr, "usage: wall [-g group] [file]\n");
178	exit(1);
179}
180
181void
182makemsg(char *fname)
183{
184	int cnt;
185	unsigned char ch;
186	struct tm *lt;
187	struct passwd *pw;
188	struct stat sbuf;
189	time_t now;
190	FILE *fp;
191	int fd;
192	char *p, hostname[MAXHOSTNAMELEN], lbuf[256], tmpname[64];
193	const char *tty;
194	const char *whom;
195	gid_t egid;
196
197	(void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
198	if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
199		err(1, "can't open temporary file");
200	(void)unlink(tmpname);
201
202	if (!nobanner) {
203		tty = ttyname(STDERR_FILENO);
204		if (tty == NULL)
205			tty = "no tty";
206
207		if (!(whom = getlogin()))
208			whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
209		(void)gethostname(hostname, sizeof(hostname));
210		(void)time(&now);
211		lt = localtime(&now);
212
213		/*
214		 * all this stuff is to blank out a square for the message;
215		 * we wrap message lines at column 79, not 80, because some
216		 * terminals wrap after 79, some do not, and we can't tell.
217		 * Which means that we may leave a non-blank character
218		 * in column 80, but that can't be helped.
219		 */
220		(void)fprintf(fp, "\r%79s\r\n", " ");
221		(void)snprintf(lbuf, sizeof(lbuf),
222		    "Broadcast Message from %s@%s",
223		    whom, hostname);
224		(void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
225		(void)snprintf(lbuf, sizeof(lbuf),
226		    "        (%s) at %d:%02d %s...", tty,
227		    lt->tm_hour, lt->tm_min, lt->tm_zone);
228		(void)fprintf(fp, "%-79.79s\r\n", lbuf);
229	}
230	(void)fprintf(fp, "%79s\r\n", " ");
231
232	if (fname) {
233		egid = getegid();
234		setegid(getgid());
235	       	if (freopen(fname, "r", stdin) == NULL)
236			err(1, "can't read %s", fname);
237		setegid(egid);
238	}
239	while (fgets(lbuf, sizeof(lbuf), stdin))
240		for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
241			if (ch == '\r') {
242				cnt = 0;
243			} else if (cnt == 79 || ch == '\n') {
244				for (; cnt < 79; ++cnt)
245					putc(' ', fp);
246				putc('\r', fp);
247				putc('\n', fp);
248				cnt = 0;
249			} else if (((ch & 0x80) && ch < 0xA0) ||
250				   /* disable upper controls */
251				   (!isprint(ch) && !isspace(ch) &&
252				    ch != '\a' && ch != '\b')
253				  ) {
254				if (ch & 0x80) {
255					ch &= 0x7F;
256					putc('M', fp);
257					if (++cnt == 79) {
258						putc('\r', fp);
259						putc('\n', fp);
260						cnt = 0;
261					}
262					putc('-', fp);
263					if (++cnt == 79) {
264						putc('\r', fp);
265						putc('\n', fp);
266						cnt = 0;
267					}
268				}
269				if (iscntrl(ch)) {
270					ch ^= 040;
271					putc('^', fp);
272					if (++cnt == 79) {
273						putc('\r', fp);
274						putc('\n', fp);
275						cnt = 0;
276					}
277				}
278				putc(ch, fp);
279			} else {
280				putc(ch, fp);
281			}
282		}
283	(void)fprintf(fp, "%79s\r\n", " ");
284	rewind(fp);
285
286	if (fstat(fd, &sbuf))
287		err(1, "can't stat temporary file");
288	mbufsize = sbuf.st_size;
289	if (!(mbuf = malloc((u_int)mbufsize)))
290		err(1, "out of memory");
291	if ((int)fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
292		err(1, "can't read temporary file");
293	(void)close(fd);
294}
295