1 /* $OpenBSD: wall.c,v 1.37 2023/03/08 04:43:12 guenther Exp $ */
2 /* $NetBSD: wall.c,v 1.6 1994/11/17 07:17:58 jtc Exp $ */
3
4 /*
5 * Copyright (c) 1988, 1990, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 /*
34 * This program is not related to David Wall, whose Stanford Ph.D. thesis
35 * is entitled "Mechanisms for Broadcast and Selective Broadcast".
36 */
37
38 #include <sys/queue.h>
39 #include <sys/stat.h>
40 #include <sys/time.h>
41 #include <sys/uio.h>
42
43 #include <ctype.h>
44 #include <err.h>
45 #include <grp.h>
46 #include <limits.h>
47 #include <paths.h>
48 #include <pwd.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <unistd.h>
53 #include <utmp.h>
54
55 struct wallgroup {
56 gid_t gid;
57 char *name;
58 char **mem;
59 struct wallgroup *next;
60 } *grouplist;
61
62 struct utmptty {
63 char *tty;
64 SLIST_ENTRY(utmptty) next;
65 };
66
67 void makemsg(char *);
68 void addgroup(struct group *, char *);
69 char *ttymsg(struct iovec *, int, char *, int);
70 __dead void usage(void);
71 static int isu8cont(unsigned char);
72
73 int nobanner;
74 int mbufsize;
75 char *mbuf;
76
77 int
main(int argc,char ** argv)78 main(int argc, char **argv)
79 {
80 FILE *fp;
81 int ch, ingroup;
82 struct iovec iov;
83 struct utmp utmp;
84 char *p, **mem;
85 char line[sizeof(utmp.ut_line) + 1];
86 char username[sizeof(utmp.ut_name) + 1];
87 struct passwd *pw;
88 struct group *grp;
89 struct wallgroup *g;
90 struct utmptty *un;
91 SLIST_HEAD(,utmptty) utmphead;
92 SLIST_INIT(&utmphead);
93
94 while ((ch = getopt(argc, argv, "ng:")) != -1)
95 switch (ch) {
96 case 'n':
97 /* undoc option for shutdown: suppress banner */
98 pw = getpwnam("nobody");
99 if (geteuid() == 0 || (pw && getuid() == pw->pw_uid))
100 nobanner = 1;
101 break;
102 case 'g':
103 if ((grp = getgrnam(optarg)) == NULL)
104 errx(1, "unknown group `%s'", optarg);
105 addgroup(grp, optarg);
106 break;
107 default:
108 usage();
109 }
110 argc -= optind;
111 argv += optind;
112 if (argc > 1)
113 usage();
114
115 makemsg(*argv);
116
117 if (unveil(_PATH_UTMP, "r") == -1)
118 err(1, "unveil %s", _PATH_UTMP);
119 if (unveil(_PATH_DEV, "w") == -1)
120 err(1, "unveil %s", _PATH_DEV);
121 if (unveil(_PATH_DEVDB, "r") == -1)
122 err(1, "unveil %s", _PATH_DEVDB);
123 if (pledge("stdio rpath wpath getpw proc", NULL) == -1)
124 err(1, "pledge");
125
126 if (!(fp = fopen(_PATH_UTMP, "r")))
127 err(1, "cannot read %s", _PATH_UTMP);
128 iov.iov_base = mbuf;
129 iov.iov_len = mbufsize;
130
131 while (fread(&utmp, sizeof(utmp), 1, fp) == 1) {
132 if (!utmp.ut_name[0])
133 continue;
134 if (grouplist) {
135 ingroup = 0;
136 strncpy(username, utmp.ut_name, sizeof(utmp.ut_name));
137 username[sizeof(utmp.ut_name)] = '\0';
138 pw = getpwnam(username);
139 if (!pw)
140 continue;
141 for (g = grouplist; g && ingroup == 0; g = g->next) {
142 if (g->gid == pw->pw_gid)
143 ingroup = 1;
144 for (mem = g->mem; *mem && ingroup == 0; mem++)
145 if (strcmp(username, *mem) == 0)
146 ingroup = 1;
147 }
148 if (ingroup == 0)
149 continue;
150 }
151 strncpy(line, utmp.ut_line, sizeof(utmp.ut_line));
152 line[sizeof(utmp.ut_line)] = '\0';
153 un = malloc(sizeof(struct utmptty));
154 if (un == NULL)
155 err(1, "malloc");
156 un->tty = strndup(line, sizeof(utmp.ut_line));
157 if (un->tty == NULL)
158 err(1, "strndup");
159 SLIST_INSERT_HEAD(&utmphead, un, next);
160 }
161 fclose(fp);
162
163 if (pledge("stdio rpath wpath proc", NULL) == -1)
164 err(1, "pledge");
165
166 SLIST_FOREACH(un, &utmphead, next) {
167 if ((p = ttymsg(&iov, 1, un->tty, 60*5)) != NULL)
168 warnx("%s", p);
169 }
170
171 exit(0);
172 }
173
174 void
makemsg(char * fname)175 makemsg(char *fname)
176 {
177 int cnt;
178 struct tm *lt;
179 struct passwd *pw;
180 struct stat sbuf;
181 time_t now;
182 FILE *fp;
183 int fd;
184 char *p, *whom, hostname[HOST_NAME_MAX+1], lbuf[100], tmpname[PATH_MAX];
185 char *ttynam;
186 unsigned char ch;
187
188 snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXXXXXX", _PATH_TMP);
189 if ((fd = mkstemp(tmpname)) >= 0) {
190 (void)unlink(tmpname);
191 fp = fdopen(fd, "r+");
192 }
193 if (fd == -1 || fp == NULL)
194 err(1, "can't open temporary file");
195
196 if (!nobanner) {
197 if (!(whom = getlogin()))
198 whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
199 (void)gethostname(hostname, sizeof(hostname));
200 (void)time(&now);
201 lt = localtime(&now);
202 if ((ttynam = ttyname(STDERR_FILENO)) == NULL)
203 ttynam = "(not a tty)";
204
205 /*
206 * all this stuff is to blank out a square for the message;
207 * we wrap message lines at column 79, not 80, because some
208 * terminals wrap after 79, some do not, and we can't tell.
209 * Which means that we may leave a non-blank character
210 * in column 80, but that can't be helped.
211 */
212 (void)fprintf(fp, "\r%79s\r\n", " ");
213 (void)snprintf(lbuf, sizeof lbuf,
214 "Broadcast Message from %s@%s", whom, hostname);
215 (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
216 (void)snprintf(lbuf, sizeof lbuf,
217 " (%s) at %d:%02d ...", ttynam,
218 lt->tm_hour, lt->tm_min);
219 (void)fprintf(fp, "%-79.79s\r\n", lbuf);
220 }
221 (void)fprintf(fp, "%79s\r\n", " ");
222
223 if (fname) {
224 gid_t egid = getegid();
225
226 setegid(getgid());
227 if (freopen(fname, "r", stdin) == NULL)
228 err(1, "can't read %s", fname);
229 setegid(egid);
230 }
231 cnt = 0;
232 while (fgets(lbuf, sizeof(lbuf), stdin))
233 for (p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
234 if (cnt == 79 || ch == '\n') {
235 for (; cnt < 79; ++cnt)
236 putc(' ', fp);
237 putc('\r', fp);
238 putc('\n', fp);
239 cnt = -1;
240 if (ch != '\n')
241 p--;
242 } else if (!isu8cont(ch))
243 putc(isprint(ch) || isspace(ch) || ch == '\a' ?
244 ch : '?', fp);
245 }
246 (void)fprintf(fp, "%79s\r\n", " ");
247 rewind(fp);
248
249 if (fstat(fd, &sbuf))
250 err(1, "can't stat temporary file");
251 mbufsize = sbuf.st_size;
252 mbuf = malloc((u_int)mbufsize);
253 if (mbuf == NULL)
254 err(1, NULL);
255 if (fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
256 err(1, "can't read temporary file");
257 (void)close(fd);
258 }
259
260 void
addgroup(struct group * grp,char * name)261 addgroup(struct group *grp, char *name)
262 {
263 int i;
264 struct wallgroup *g;
265
266 for (i = 0; grp->gr_mem[i]; i++)
267 ;
268
269 g = malloc(sizeof *g);
270 if (g == NULL)
271 err(1, NULL);
272 g->gid = grp->gr_gid;
273 g->name = name;
274 g->mem = calloc(i + 1, sizeof(char *));
275 if (g->mem == NULL)
276 err(1, NULL);
277 for (i = 0; grp->gr_mem[i] != NULL; i++) {
278 g->mem[i] = strdup(grp->gr_mem[i]);
279 if (g->mem[i] == NULL)
280 err(1, NULL);
281 }
282 g->mem[i] = NULL;
283 g->next = grouplist;
284 grouplist = g;
285 }
286
287 void
usage(void)288 usage(void)
289 {
290 extern char *__progname;
291
292 (void)fprintf(stderr, "usage: %s [-g group] [file]\n", __progname);
293 exit(1);
294 }
295
296 static int
isu8cont(unsigned char c)297 isu8cont(unsigned char c)
298 {
299 return (c & (0x80 | 0x40)) == 0x80;
300 }
301