xref: /freebsd/usr.bin/wall/wall.c (revision 734e82fe33aa764367791a7d603b383996c6b40b)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1988, 1990, 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 
33 #ifndef lint
34 static const char copyright[] =
35 "@(#) Copyright (c) 1988, 1990, 1993\n\
36 	The Regents of the University of California.  All rights reserved.\n";
37 #endif
38 
39 #ifndef lint
40 static const char sccsid[] = "@(#)wall.c	8.2 (Berkeley) 11/16/93";
41 #endif
42 
43 /*
44  * This program is not related to David Wall, whose Stanford Ph.D. thesis
45  * is entitled "Mechanisms for Broadcast and Selective Broadcast".
46  */
47 
48 #include <sys/param.h>
49 #include <sys/stat.h>
50 #include <sys/uio.h>
51 
52 #include <ctype.h>
53 #include <err.h>
54 #include <grp.h>
55 #include <locale.h>
56 #include <paths.h>
57 #include <pwd.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <time.h>
62 #include <unistd.h>
63 #include <utmpx.h>
64 #include <wchar.h>
65 #include <wctype.h>
66 
67 #include "ttymsg.h"
68 
69 static void makemsg(char *);
70 static void usage(void) __dead2;
71 
72 static struct wallgroup {
73 	struct wallgroup *next;
74 	char		*name;
75 	gid_t		gid;
76 } *grouplist;
77 static int nobanner;
78 static int mbufsize;
79 static char *mbuf;
80 
81 static int
82 ttystat(char *line)
83 {
84 	struct stat sb;
85 	char ttybuf[MAXPATHLEN];
86 
87 	(void)snprintf(ttybuf, sizeof(ttybuf), "%s%s", _PATH_DEV, line);
88 	if (stat(ttybuf, &sb) == 0) {
89 		return (0);
90 	} else
91 		return (-1);
92 }
93 
94 int
95 main(int argc, char *argv[])
96 {
97 	struct iovec iov;
98 	struct utmpx *utmp;
99 	int ch;
100 	int ingroup;
101 	struct wallgroup *g;
102 	struct group *grp;
103 	char **np;
104 	const char *p;
105 	struct passwd *pw;
106 
107 	(void)setlocale(LC_CTYPE, "");
108 
109 	while ((ch = getopt(argc, argv, "g:n")) != -1)
110 		switch (ch) {
111 		case 'n':
112 			/* undoc option for shutdown: suppress banner */
113 			if (geteuid() == 0)
114 				nobanner = 1;
115 			break;
116 		case 'g':
117 			g = (struct wallgroup *)malloc(sizeof *g);
118 			g->next = grouplist;
119 			g->name = optarg;
120 			g->gid = -1;
121 			grouplist = g;
122 			break;
123 		case '?':
124 		default:
125 			usage();
126 		}
127 	argc -= optind;
128 	argv += optind;
129 	if (argc > 1)
130 		usage();
131 
132 	for (g = grouplist; g; g = g->next) {
133 		grp = getgrnam(g->name);
134 		if (grp != NULL)
135 			g->gid = grp->gr_gid;
136 		else
137 			warnx("%s: no such group", g->name);
138 	}
139 
140 	makemsg(*argv);
141 
142 	iov.iov_base = mbuf;
143 	iov.iov_len = mbufsize;
144 	/* NOSTRICT */
145 	while ((utmp = getutxent()) != NULL) {
146 		if (utmp->ut_type != USER_PROCESS)
147 			continue;
148 		if (ttystat(utmp->ut_line) != 0)
149 			continue;
150 		if (grouplist) {
151 			ingroup = 0;
152 			pw = getpwnam(utmp->ut_user);
153 			if (!pw)
154 				continue;
155 			for (g = grouplist; g && ingroup == 0; g = g->next) {
156 				if (g->gid == (gid_t)-1)
157 					continue;
158 				if (g->gid == pw->pw_gid)
159 					ingroup = 1;
160 				else if ((grp = getgrgid(g->gid)) != NULL) {
161 					for (np = grp->gr_mem; *np; np++) {
162 						if (strcmp(*np, utmp->ut_user) == 0) {
163 							ingroup = 1;
164 							break;
165 						}
166 					}
167 				}
168 			}
169 			if (ingroup == 0)
170 				continue;
171 		}
172 		if ((p = ttymsg(&iov, 1, utmp->ut_line, 60*5)) != NULL)
173 			warnx("%s", p);
174 	}
175 	exit(0);
176 }
177 
178 static void
179 usage(void)
180 {
181 	(void)fprintf(stderr, "usage: wall [-g group] [file]\n");
182 	exit(1);
183 }
184 
185 void
186 makemsg(char *fname)
187 {
188 	int cnt;
189 	wchar_t ch;
190 	struct tm *lt;
191 	struct passwd *pw;
192 	struct stat sbuf;
193 	time_t now;
194 	FILE *fp;
195 	int fd;
196 	char hostname[MAXHOSTNAMELEN], tmpname[64];
197 	wchar_t *p, *tmp, lbuf[256], codebuf[13];
198 	const char *tty;
199 	const char *whom;
200 	gid_t egid;
201 
202 	(void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
203 	if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
204 		err(1, "can't open temporary file");
205 	(void)unlink(tmpname);
206 
207 	if (!nobanner) {
208 		tty = ttyname(STDERR_FILENO);
209 		if (tty == NULL)
210 			tty = "no tty";
211 
212 		if (!(whom = getlogin()))
213 			whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
214 		(void)gethostname(hostname, sizeof(hostname));
215 		(void)time(&now);
216 		lt = localtime(&now);
217 
218 		/*
219 		 * all this stuff is to blank out a square for the message;
220 		 * we wrap message lines at column 79, not 80, because some
221 		 * terminals wrap after 79, some do not, and we can't tell.
222 		 * Which means that we may leave a non-blank character
223 		 * in column 80, but that can't be helped.
224 		 */
225 		(void)fwprintf(fp, L"\r%79s\r\n", " ");
226 		(void)swprintf(lbuf, sizeof(lbuf)/sizeof(wchar_t),
227 		    L"Broadcast Message from %s@%s",
228 		    whom, hostname);
229 		(void)fwprintf(fp, L"%-79.79S\007\007\r\n", lbuf);
230 		(void)swprintf(lbuf, sizeof(lbuf)/sizeof(wchar_t),
231 		    L"        (%s) at %d:%02d %s...", tty,
232 		    lt->tm_hour, lt->tm_min, lt->tm_zone);
233 		(void)fwprintf(fp, L"%-79.79S\r\n", lbuf);
234 	}
235 	(void)fwprintf(fp, L"%79s\r\n", " ");
236 
237 	if (fname) {
238 		egid = getegid();
239 		setegid(getgid());
240 		if (freopen(fname, "r", stdin) == NULL)
241 			err(1, "can't read %s", fname);
242 		if (setegid(egid) != 0)
243 			err(1, "setegid failed");
244 	}
245 	cnt = 0;
246 	while (fgetws(lbuf, sizeof(lbuf)/sizeof(wchar_t), stdin)) {
247 		for (p = lbuf; (ch = *p) != L'\0'; ++p, ++cnt) {
248 			if (ch == L'\r') {
249 				putwc(L'\r', fp);
250 				cnt = 0;
251 				continue;
252 			} else if (ch == L'\n') {
253 				for (; cnt < 79; ++cnt)
254 					putwc(L' ', fp);
255 				putwc(L'\r', fp);
256 				putwc(L'\n', fp);
257 				break;
258 			}
259 			if (cnt == 79) {
260 				putwc(L'\r', fp);
261 				putwc(L'\n', fp);
262 				cnt = 0;
263 			}
264 			if (iswprint(ch) || iswspace(ch) || ch == L'\a' || ch == L'\b') {
265 				putwc(ch, fp);
266 			} else {
267 				(void)swprintf(codebuf, sizeof(codebuf)/sizeof(wchar_t), L"<0x%X>", ch);
268 				for (tmp = codebuf; *tmp != L'\0'; ++tmp) {
269 					putwc(*tmp, fp);
270 					if (++cnt == 79) {
271 						putwc(L'\r', fp);
272 						putwc(L'\n', fp);
273 						cnt = 0;
274 					}
275 				}
276 				--cnt;
277 			}
278 		}
279 	}
280 	(void)fwprintf(fp, L"%79s\r\n", " ");
281 	rewind(fp);
282 
283 	if (fstat(fd, &sbuf))
284 		err(1, "can't stat temporary file");
285 	mbufsize = sbuf.st_size;
286 	if (!(mbuf = malloc((u_int)mbufsize)))
287 		err(1, "out of memory");
288 	if ((int)fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
289 		err(1, "can't read temporary file");
290 	fclose(fp);
291 }
292