wall.c revision 87675 
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 87675 2001-12-11 22:22:15Z markm $");
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
75#define	IGNOREUSER	"sleeper"
76
77struct wallgroup {
78	struct wallgroup *next;
79	char		*name;
80	gid_t		gid;
81} *grouplist;
82int nobanner;
83int mbufsize;
84char *mbuf;
85
86int
87main(int argc, char *argv[])
88{
89	struct iovec iov;
90	struct utmp utmp;
91	int ch;
92	int ingroup;
93	FILE *fp;
94	struct wallgroup *g;
95	struct group *grp;
96	char **np;
97	const char *p;
98	struct passwd *pw;
99	char line[sizeof(utmp.ut_line) + 1];
100	char username[sizeof(utmp.ut_name) + 1];
101
102	(void)setlocale(LC_CTYPE, "");
103
104	while ((ch = getopt(argc, argv, "g:n")) != -1)
105		switch (ch) {
106		case 'n':
107			/* undoc option for shutdown: suppress banner */
108			if (geteuid() == 0)
109				nobanner = 1;
110			break;
111		case 'g':
112			g = (struct wallgroup *)malloc(sizeof *g);
113			g->next = grouplist;
114			g->name = optarg;
115			g->gid = -1;
116			grouplist = g;
117			break;
118		case '?':
119		default:
120			usage();
121		}
122	argc -= optind;
123	argv += optind;
124	if (argc > 1)
125		usage();
126
127	for (g = grouplist; g; g = g->next) {
128		grp = getgrnam(g->name);
129		if (grp != NULL)
130			g->gid = grp->gr_gid;
131		else
132			warnx("%s: no such group", g->name);
133	}
134
135	makemsg(*argv);
136
137	if (!(fp = fopen(_PATH_UTMP, "r")))
138		err(1, "cannot read %s", _PATH_UTMP);
139	iov.iov_base = mbuf;
140	iov.iov_len = mbufsize;
141	/* NOSTRICT */
142	while (fread((char *)&utmp, sizeof(utmp), 1, fp) == 1) {
143		if (!utmp.ut_name[0] ||
144		    !strncmp(utmp.ut_name, IGNOREUSER, sizeof(utmp.ut_name)))
145			continue;
146		if (grouplist) {
147			ingroup = 0;
148			strlcpy(username, utmp.ut_name, sizeof(utmp.ut_name));
149			pw = getpwnam(username);
150			if (!pw)
151				continue;
152			for (g = grouplist; g && ingroup == 0; g = g->next) {
153				if (g->gid == (gid_t)-1)
154					continue;
155				if (g->gid == pw->pw_gid)
156					ingroup = 1;
157				else if ((grp = getgrgid(g->gid)) != NULL) {
158					for (np = grp->gr_mem; *np; np++) {
159						if (strcmp(*np, username) == 0) {
160							ingroup = 1;
161							break;
162						}
163					}
164				}
165			}
166			if (ingroup == 0)
167				continue;
168		}
169		strncpy(line, utmp.ut_line, sizeof(utmp.ut_line));
170		line[sizeof(utmp.ut_line)] = '\0';
171		if ((p = ttymsg(&iov, 1, line, 60*5)) != NULL)
172			warnx("%s", p);
173	}
174	exit(0);
175}
176
177static void
178usage()
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	while (fgets(lbuf, sizeof(lbuf), stdin))
243		for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
244			if (ch == '\r') {
245				cnt = 0;
246			} else if (cnt == 79 || ch == '\n') {
247				for (; cnt < 79; ++cnt)
248					putc(' ', fp);
249				putc('\r', fp);
250				putc('\n', fp);
251				cnt = 0;
252			} else if (((ch & 0x80) && ch < 0xA0) ||
253				   /* disable upper controls */
254				   (!isprint(ch) && !isspace(ch) &&
255				    ch != '\a' && ch != '\b')
256				  ) {
257				if (ch & 0x80) {
258					ch &= 0x7F;
259					putc('M', fp);
260					if (++cnt == 79) {
261						putc('\r', fp);
262						putc('\n', fp);
263						cnt = 0;
264					}
265					putc('-', fp);
266					if (++cnt == 79) {
267						putc('\r', fp);
268						putc('\n', fp);
269						cnt = 0;
270					}
271				}
272				if (iscntrl(ch)) {
273					ch ^= 040;
274					putc('^', fp);
275					if (++cnt == 79) {
276						putc('\r', fp);
277						putc('\n', fp);
278						cnt = 0;
279					}
280				}
281				putc(ch, fp);
282			} else {
283				putc(ch, fp);
284			}
285		}
286	(void)fprintf(fp, "%79s\r\n", " ");
287	rewind(fp);
288
289	if (fstat(fd, &sbuf))
290		err(1, "can't stat temporary file");
291	mbufsize = sbuf.st_size;
292	if (!(mbuf = malloc((u_int)mbufsize)))
293		err(1, "out of memory");
294	if ((int)fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
295		err(1, "can't read temporary file");
296	(void)close(fd);
297}
298