1 /* $NetBSD: wall.c,v 1.30 2015/11/21 14:59:51 christos Exp $ */
2
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 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT("@(#) Copyright (c) 1988, 1990, 1993\
35 The Regents of the University of California. All rights reserved.");
36 #endif /* not lint */
37
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)wall.c 8.2 (Berkeley) 11/16/93";
41 #endif
42 __RCSID("$NetBSD: wall.c,v 1.30 2015/11/21 14:59:51 christos Exp $");
43 #endif /* not lint */
44
45 /*
46 * This program is not related to David Wall, whose Stanford Ph.D. thesis
47 * is entitled "Mechanisms for Broadcast and Selective Broadcast".
48 */
49
50 #include <sys/param.h>
51 #include <sys/stat.h>
52 #include <sys/time.h>
53 #include <sys/uio.h>
54
55 #include <ctype.h>
56 #include <err.h>
57 #include <grp.h>
58 #include <errno.h>
59 #include <paths.h>
60 #include <pwd.h>
61 #include <stdio.h>
62 #include <stdlib.h>
63 #include <string.h>
64 #include <unistd.h>
65 #include <util.h>
66
67 #include "utmpentry.h"
68 #include "term_chk.h"
69
70 static void addgroup(char *);
71 static void makemsg(struct iovec *, const char *, int);
72 __dead static void usage(void);
73
74 static struct wallgroup {
75 gid_t gid;
76 char *name;
77 char **mem;
78 struct wallgroup *next;
79 } *grouplist;
80
81 int
main(int argc,char ** argv)82 main(int argc, char **argv)
83 {
84 int ch;
85 struct iovec iov;
86 char *p, **mem;
87 struct utmpentry *ep;
88 gid_t egid;
89 struct wallgroup *wg;
90 struct passwd *pw;
91 int nobanner;
92
93 setprogname(argv[0]);
94 egid = getegid();
95 if (setegid(getgid()) == -1)
96 err(EXIT_FAILURE, "setegid");
97 pw = getpwnam("nobody");
98 if (pw == NULL)
99 errx(EXIT_FAILURE, "Can't find passwd entry for `nobody'");
100
101 (void)check_sender(NULL, getuid(), egid);
102
103 nobanner = 0;
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 || (pw && getuid() == pw->pw_uid))
109 nobanner = 1;
110 break;
111 case 'g':
112 addgroup(optarg);
113 break;
114 case '?':
115 default:
116 usage();
117 }
118 argc -= optind;
119 argv += optind;
120 if (argc > 1)
121 usage();
122
123 makemsg(&iov, *argv, nobanner);
124
125 (void)getutentries(NULL, &ep);
126 (void)setegid(egid);
127 for (; ep; ep = ep->next) {
128 if (grouplist) {
129 int ingroup;
130
131 ingroup = 0;
132 pw = getpwnam(ep->name);
133 if (!pw)
134 continue;
135 for (wg = grouplist; wg && !ingroup; wg = wg->next) {
136 if (wg->gid == pw->pw_gid)
137 ingroup = 1;
138 for (mem = wg->mem; *mem && !ingroup; mem++)
139 if (strcmp(ep->name, *mem) == 0)
140 ingroup = 1;
141 }
142 if (ingroup == 0)
143 continue;
144 }
145
146 /* skip [xgk]dm/xserver entries (":0", ":1", etc.) */
147 if (ep->line[0] == ':' && isdigit((unsigned char)ep->line[1]))
148 continue;
149
150 if ((p = ttymsg(&iov, 1, ep->line, 60*5)) != NULL)
151 warnx("%s", p);
152 }
153 return EXIT_SUCCESS;
154 }
155
156 static void
addgroup(char * name)157 addgroup(char *name)
158 {
159 size_t i;
160 struct group *grp;
161 struct wallgroup *g;
162
163 grp = getgrnam(name);
164 if ((grp = getgrnam(name)) == NULL)
165 errx(EXIT_FAILURE, "unknown group `%s'", name);
166 for (i = 0; grp->gr_mem[i]; i++)
167 continue;
168
169 g = malloc(sizeof(*g));
170 if (g == NULL)
171 err(EXIT_FAILURE, "malloc");
172 g->gid = grp->gr_gid;
173 g->name = name;
174 g->mem = calloc(i + 1, sizeof(*g->mem));
175 if (g->mem == NULL)
176 err(EXIT_FAILURE, "calloc");
177 for (i = 0; grp->gr_mem[i] != NULL; i++) {
178 g->mem[i] = strdup(grp->gr_mem[i]);
179 if (g->mem[i] == NULL)
180 err(EXIT_FAILURE, "strdup");
181 }
182 g->mem[i] = NULL;
183 g->next = grouplist;
184 grouplist = g;
185 }
186
187 static void
makebanner(FILE * fp)188 makebanner(FILE *fp)
189 {
190 const char *whom, *tty;
191 char hostname[MAXHOSTNAMELEN + 1], lbuf[100];
192 time_t now;
193 struct tm *lt;
194 struct passwd *pw;
195
196 if (!(whom = getlogin()))
197 whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
198 (void)gethostname(hostname, sizeof(hostname));
199 hostname[sizeof(hostname) - 1] = '\0';
200 (void)time(&now);
201 lt = localtime(&now);
202
203 /*
204 * all this stuff is to blank out a square for the message;
205 * we wrap message lines at column 79, not 80, because some
206 * terminals wrap after 79, some do not, and we can't tell.
207 * Which means that we may leave a non-blank character
208 * in column 80, but that can't be helped.
209 */
210 (void)fprintf(fp, "\r%79s\r\n", " ");
211 (void)snprintf(lbuf, sizeof lbuf,
212 "Broadcast Message from %s@%s", whom, hostname);
213 (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
214 tty = ttyname(STDERR_FILENO);
215 if (tty == NULL)
216 tty = "??";
217 (void)snprintf(lbuf, sizeof lbuf, " (%s) at %d:%02d %s...", tty,
218 lt->tm_hour, lt->tm_min, lt->tm_zone);
219 (void)fprintf(fp, "%-79.79s\r\n", lbuf);
220 }
221
222 static void
makemsg(struct iovec * iov,const char * fname,int nobanner)223 makemsg(struct iovec *iov, const char *fname, int nobanner)
224 {
225 int ch, cnt;
226 struct stat sbuf;
227 FILE *fp;
228 int fd;
229 char *p, tmpname[MAXPATHLEN], lbuf[100];
230 size_t mbufsize;
231 char *mbuf;
232
233 (void)snprintf(tmpname, sizeof tmpname, "%s/wall.XXXXXX", _PATH_TMP);
234 if ((fd = mkstemp(tmpname)) == -1)
235 err(EXIT_FAILURE, "can't open temporary file");
236 (void)unlink(tmpname);
237 if (!(fp = fdopen(fd, "r+")))
238 err(EXIT_FAILURE, "can't open temporary file");
239
240 if (!nobanner)
241 makebanner(fp);
242
243 (void)fprintf(fp, "%79s\r\n", " ");
244
245 if (fname && !(freopen(fname, "r", stdin)))
246 err(EXIT_FAILURE, "can't read %s", fname);
247
248 while (fgets(lbuf, sizeof(lbuf), stdin))
249 for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
250 if (cnt == 79 || ch == '\n') {
251 for (; cnt < 79; ++cnt)
252 putc(' ', fp);
253 putc('\r', fp);
254 putc('\n', fp);
255 cnt = -1;
256 }
257 if (ch != '\n')
258 putc(ch, fp);
259 }
260 (void)fprintf(fp, "%79s\r\n", " ");
261 rewind(fp);
262
263 if (fstat(fd, &sbuf) == -1)
264 err(EXIT_FAILURE, "can't stat temporary file");
265 if ((uint64_t)sbuf.st_size > SIZE_T_MAX)
266 errx(EXIT_FAILURE, "file too big");
267 mbufsize = (size_t)sbuf.st_size;
268 if (!(mbuf = malloc(mbufsize)))
269 err(EXIT_FAILURE, "malloc");
270 if (fread(mbuf, 1, mbufsize, fp) != mbufsize)
271 err(EXIT_FAILURE, "can't read temporary file");
272 (void)fclose(fp);
273 iov->iov_base = mbuf;
274 iov->iov_len = mbufsize;
275 }
276
277 static void
usage(void)278 usage(void)
279 {
280
281 (void)fprintf(stderr, "Usage: %s [-g group] [file]\n", getprogname());
282 exit(EXIT_FAILURE);
283 }
284