1 /* $OpenBSD: wall.c,v 1.14 2001/02/13 09:16:04 deraadt 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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 static char copyright[] = 39 "@(#) Copyright (c) 1988, 1990, 1993\n\ 40 The Regents of the University of California. All rights reserved.\n"; 41 #endif /* not lint */ 42 43 #ifndef lint 44 #if 0 45 static char sccsid[] = "@(#)wall.c 8.2 (Berkeley) 11/16/93"; 46 #endif 47 static char rcsid[] = "$OpenBSD: wall.c,v 1.14 2001/02/13 09:16:04 deraadt Exp $"; 48 #endif /* not lint */ 49 50 /* 51 * This program is not related to David Wall, whose Stanford Ph.D. thesis 52 * is entitled "Mechanisms for Broadcast and Selective Broadcast". 53 */ 54 55 #include <sys/param.h> 56 #include <sys/stat.h> 57 #include <sys/time.h> 58 #include <sys/uio.h> 59 60 #include <paths.h> 61 #include <pwd.h> 62 #include <grp.h> 63 #include <stdio.h> 64 #include <stdlib.h> 65 #include <string.h> 66 #include <unistd.h> 67 #include <utmp.h> 68 #include <vis.h> 69 #include <err.h> 70 71 struct wallgroup { 72 struct wallgroup *next; 73 char *name; 74 gid_t gid; 75 } *grouplist; 76 77 void makemsg __P((char *)); 78 79 #define IGNOREUSER "sleeper" 80 81 int nobanner; 82 int mbufsize; 83 char *mbuf; 84 85 /* ARGSUSED */ 86 int 87 main(argc, argv) 88 int argc; 89 char **argv; 90 { 91 extern int optind; 92 int ch; 93 struct iovec iov; 94 struct utmp utmp; 95 FILE *fp; 96 char *p, *ttymsg(); 97 struct passwd *pep = getpwnam("nobody"); 98 char line[sizeof(utmp.ut_line) + 1]; 99 struct wallgroup *g; 100 101 while ((ch = getopt(argc, argv, "ng:")) != -1) 102 switch (ch) { 103 case 'n': 104 /* undoc option for shutdown: suppress banner */ 105 if (geteuid() == 0 || (pep && getuid() == pep->pw_uid)) 106 nobanner = 1; 107 break; 108 case 'g': 109 g = (struct wallgroup *)malloc(sizeof *g); 110 g->next = grouplist; 111 g->name = optarg; 112 g->gid = -1; 113 grouplist = g; 114 break; 115 case '?': 116 default: 117 usage: 118 (void)fprintf(stderr, "usage: wall [-g group] [file]\n"); 119 exit(1); 120 } 121 argc -= optind; 122 argv += optind; 123 if (argc > 1) 124 goto usage; 125 126 for (g = grouplist; g; g = g->next) { 127 struct group *grp; 128 129 grp = getgrnam(g->name); 130 if (grp) 131 g->gid = grp->gr_gid; 132 } 133 134 makemsg(*argv); 135 136 if (!(fp = fopen(_PATH_UTMP, "r"))) 137 errx(1, "cannot read %s.", _PATH_UTMP); 138 iov.iov_base = mbuf; 139 iov.iov_len = mbufsize; 140 /* NOSTRICT */ 141 while (fread((char *)&utmp, sizeof(utmp), 1, fp) == 1) { 142 if (!utmp.ut_name[0] || 143 !strncmp(utmp.ut_name, IGNOREUSER, sizeof(utmp.ut_name))) 144 continue; 145 if (grouplist) { 146 int ingroup = 0, ngrps, i; 147 char username[MAXLOGNAME]; 148 struct passwd *pw; 149 gid_t grps[NGROUPS_MAX]; 150 151 bzero(username, sizeof username); 152 strncpy(username, utmp.ut_name, sizeof utmp.ut_name); 153 pw = getpwnam(username); 154 if (!pw) 155 continue; 156 ngrps = getgroups(pw->pw_gid, grps); 157 for (g = grouplist; g && ingroup == 0; g = g->next) { 158 if (g->gid == -1) 159 continue; 160 if (g->gid == pw->pw_gid) 161 ingroup = 1; 162 for (i = 0; i < ngrps && ingroup == 0; i++) 163 if (g->gid == grps[i]) 164 ingroup = 1; 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 } 176 177 void 178 makemsg(fname) 179 char *fname; 180 { 181 register int ch, cnt; 182 struct tm *lt; 183 struct passwd *pw; 184 struct stat sbuf; 185 time_t now, time(); 186 FILE *fp; 187 int fd; 188 char *p, *whom, hostname[MAXHOSTNAMELEN], lbuf[100], tmpname[64]; 189 char tmpbuf[5]; 190 char *ttynam; 191 192 snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP); 193 if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+"))) 194 errx(1, "can't open temporary file."); 195 (void)unlink(tmpname); 196 197 if (!nobanner) { 198 if (!(whom = getlogin())) 199 whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???"; 200 (void)gethostname(hostname, sizeof(hostname)); 201 (void)time(&now); 202 lt = localtime(&now); 203 if ((ttynam = ttyname(STDERR_FILENO)) == NULL) 204 ttynam = "(not a tty)"; 205 206 /* 207 * all this stuff is to blank out a square for the message; 208 * we wrap message lines at column 79, not 80, because some 209 * terminals wrap after 79, some do not, and we can't tell. 210 * Which means that we may leave a non-blank character 211 * in column 80, but that can't be helped. 212 */ 213 (void)fprintf(fp, "\r%79s\r\n", " "); 214 (void)snprintf(lbuf, sizeof lbuf, 215 "Broadcast Message from %s@%s", whom, hostname); 216 (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf); 217 (void)snprintf(lbuf, sizeof lbuf, 218 " (%s) at %d:%02d ...", ttynam, 219 lt->tm_hour, lt->tm_min); 220 (void)fprintf(fp, "%-79.79s\r\n", lbuf); 221 } 222 (void)fprintf(fp, "%79s\r\n", " "); 223 224 if (fname) { 225 gid_t egid = getegid(); 226 227 setegid(getgid()); 228 if (freopen(fname, "r", stdin) == NULL) 229 errx(1, "can't read %s.", fname); 230 setegid(egid); 231 } 232 while (fgets(lbuf, sizeof(lbuf), stdin)) 233 for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) { 234 vis(tmpbuf, ch, VIS_SAFE|VIS_NOSLASH, p[1]); 235 if (cnt == 79+1-strlen(tmpbuf) || ch == '\n') { 236 for (; cnt < 79+1-strlen(tmpbuf); ++cnt) 237 putc(' ', fp); 238 putc('\r', fp); 239 putc('\n', fp); 240 cnt = -1; 241 } 242 if (ch != '\n') { 243 int xx; 244 245 for (xx = 0; tmpbuf[xx]; xx++) 246 putc(tmpbuf[xx], fp); 247 } 248 } 249 (void)fprintf(fp, "%79s\r\n", " "); 250 rewind(fp); 251 252 if (fstat(fd, &sbuf)) 253 errx(1, "can't stat temporary file."); 254 mbufsize = sbuf.st_size; 255 if (!(mbuf = malloc((u_int)mbufsize))) 256 errx(1, "out of memory."); 257 if (fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize) 258 errx(1, "can't read temporary file."); 259 (void)close(fd); 260 } 261