1 /* $NetBSD: wall.c,v 1.29 2011/09/06 18:45:21 joerg 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 1.29 2011/09/06 18:45:21 joerg 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(const char *); 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 static int nobanner; 82 static size_t mbufsize; 83 static char *mbuf; 84 85 /* ARGSUSED */ 86 int 87 main(int argc, char **argv) 88 { 89 int ch; 90 struct iovec iov; 91 char *p, **mem; 92 struct utmpentry *ep; 93 gid_t egid; 94 struct wallgroup *wg; 95 struct passwd *pw; 96 97 setprogname(argv[0]); 98 egid = getegid(); 99 if (setegid(getgid()) == -1) 100 err(1, "setegid"); 101 pw = getpwnam("nobody"); 102 103 (void)check_sender(NULL, getuid(), egid); 104 105 while ((ch = getopt(argc, argv, "g:n")) != -1) 106 switch (ch) { 107 case 'n': 108 /* undoc option for shutdown: suppress banner */ 109 if (geteuid() == 0 || (pw && getuid() == pw->pw_uid)) 110 nobanner = 1; 111 break; 112 case 'g': 113 addgroup(optarg); 114 break; 115 case '?': 116 default: 117 usage(); 118 } 119 argc -= optind; 120 argv += optind; 121 if (argc > 1) 122 usage(); 123 124 makemsg(*argv); 125 126 iov.iov_base = mbuf; 127 iov.iov_len = mbufsize; 128 (void)getutentries(NULL, &ep); 129 (void)setegid(egid); 130 for (; ep; ep = ep->next) { 131 if (grouplist) { 132 int ingroup; 133 134 ingroup = 0; 135 pw = getpwnam(ep->name); 136 if (!pw) 137 continue; 138 for (wg = grouplist; wg && !ingroup; wg = wg->next) { 139 if (wg->gid == pw->pw_gid) 140 ingroup = 1; 141 for (mem = wg->mem; *mem && !ingroup; mem++) 142 if (strcmp(ep->name, *mem) == 0) 143 ingroup = 1; 144 } 145 if (ingroup == 0) 146 continue; 147 } 148 149 /* skip [xgk]dm/xserver entries (":0", ":1", etc.) */ 150 if (ep->line[0] == ':' && isdigit((unsigned char)ep->line[1])) 151 continue; 152 153 if ((p = ttymsg(&iov, 1, ep->line, 60*5)) != NULL) 154 warnx("%s", p); 155 } 156 exit(0); 157 } 158 159 static void 160 addgroup(char *name) 161 { 162 int i; 163 struct group *grp; 164 struct wallgroup *g; 165 166 grp = getgrnam(name); 167 if ((grp = getgrnam(name)) == NULL) 168 errx(1, "unknown group `%s'", name); 169 for (i = 0; grp->gr_mem[i]; i++) 170 continue; 171 172 g = (struct wallgroup *)malloc(sizeof *g); 173 if (g == NULL) 174 err(1, "malloc"); 175 g->gid = grp->gr_gid; 176 g->name = name; 177 g->mem = (char **)malloc(i + 1); 178 if (g->mem == NULL) 179 err(1, "malloc"); 180 for (i = 0; grp->gr_mem[i] != NULL; i++) { 181 g->mem[i] = strdup(grp->gr_mem[i]); 182 if (g->mem[i] == NULL) 183 err(1, "malloc"); 184 } 185 g->mem[i] = NULL; 186 g->next = grouplist; 187 grouplist = g; 188 } 189 190 static void 191 makemsg(const char *fname) 192 { 193 int ch, cnt; 194 struct tm *lt; 195 struct passwd *pw; 196 struct stat sbuf; 197 time_t now; 198 FILE *fp; 199 int fd; 200 const char *whom, *tty; 201 char *p, tmpname[MAXPATHLEN], lbuf[100], 202 hostname[MAXHOSTNAMELEN+1]; 203 204 (void)snprintf(tmpname, sizeof tmpname, "%s/wall.XXXXXX", _PATH_TMP); 205 if ((fd = mkstemp(tmpname)) == -1) 206 err(1, "can't open temporary file"); 207 (void)unlink(tmpname); 208 if (!(fp = fdopen(fd, "r+"))) 209 err(1, "can't open temporary file"); 210 211 if (!nobanner) { 212 if (!(whom = getlogin())) 213 whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???"; 214 (void)gethostname(hostname, sizeof(hostname)); 215 hostname[sizeof(hostname) - 1] = '\0'; 216 (void)time(&now); 217 lt = localtime(&now); 218 219 /* 220 * all this stuff is to blank out a square for the message; 221 * we wrap message lines at column 79, not 80, because some 222 * terminals wrap after 79, some do not, and we can't tell. 223 * Which means that we may leave a non-blank character 224 * in column 80, but that can't be helped. 225 */ 226 (void)fprintf(fp, "\r%79s\r\n", " "); 227 (void)snprintf(lbuf, sizeof lbuf, 228 "Broadcast Message from %s@%s", whom, hostname); 229 (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf); 230 tty = ttyname(STDERR_FILENO); 231 if (tty == NULL) 232 tty = "??"; 233 (void)snprintf(lbuf, sizeof lbuf, 234 " (%s) at %d:%02d %s...", tty, 235 lt->tm_hour, lt->tm_min, lt->tm_zone); 236 (void)fprintf(fp, "%-79.79s\r\n", lbuf); 237 } 238 (void)fprintf(fp, "%79s\r\n", " "); 239 240 if (fname && !(freopen(fname, "r", stdin))) 241 err(1, "can't read %s", fname); 242 while (fgets(lbuf, sizeof(lbuf), stdin)) 243 for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) { 244 if (cnt == 79 || ch == '\n') { 245 for (; cnt < 79; ++cnt) 246 putc(' ', fp); 247 putc('\r', fp); 248 putc('\n', fp); 249 cnt = -1; 250 } 251 if (ch != '\n') 252 putc(ch, fp); 253 } 254 (void)fprintf(fp, "%79s\r\n", " "); 255 rewind(fp); 256 257 if (fstat(fd, &sbuf)) 258 err(1, "can't stat temporary file"); 259 if ((uint64_t)sbuf.st_size > SIZE_T_MAX) 260 errx(1, "file too big"); 261 mbufsize = sbuf.st_size; 262 if (!(mbuf = malloc(mbufsize))) 263 err(1, "malloc"); 264 if (fread(mbuf, 1, mbufsize, fp) != mbufsize) 265 err(1, "can't read temporary file"); 266 (void)fclose(fp); 267 } 268 269 static void 270 usage(void) 271 { 272 273 (void)fprintf(stderr, "usage: %s [-g group] [file]\n", getprogname()); 274 exit(1); 275 } 276