usr.bin/wall/wall.c

   1 /*
   2  * Copyright (c) 1988, 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <sys/cdefs.h>
  35
  36 __FBSDID("$FreeBSD$");
  37
  38 #ifndef lint
  39 static const char copyright[] =
  40 "@(#) Copyright (c) 1988, 1990, 1993\n\
  41         The Regents of the University of California.  All rights reserved.\n";
  42 #endif
  43
  44 #ifndef lint
  45 static const char sccsid[] = "@(#)wall.c        8.2 (Berkeley) 11/16/93";
  46 #endif
  47
  48 /*
  49  * This program is not related to David Wall, whose Stanford Ph.D. thesis
  50  * is entitled "Mechanisms for Broadcast and Selective Broadcast".
  51  */
  52
  53 #include <sys/param.h>
  54 #include <sys/stat.h>
  55 #include <sys/uio.h>
  56
  57 #include <ctype.h>
  58 #include <err.h>
  59 #include <grp.h>
  60 #include <locale.h>
  61 #include <paths.h>
  62 #include <pwd.h>
  63 #include <stdio.h>
  64 #include <stdlib.h>
  65 #include <string.h>
  66 #include <time.h>
  67 #include <unistd.h>
  68 #include <utmp.h>
  69
  70 #include "ttymsg.h"
  71
  72 static void makemsg(char *);
  73 static void usage(void);
  74
  75 struct wallgroup {
  76         struct wallgroup *next;
  77         char            *name;
  78         gid_t           gid;
  79 } *grouplist;
  80 int nobanner;
  81 int mbufsize;
  82 char *mbuf;
  83
  84 static int
  85 ttystat(char *line, int sz)
  86 {
  87         struct stat sb;
  88         char ttybuf[MAXPATHLEN];
  89
  90         (void)snprintf(ttybuf, sizeof(ttybuf), "%s%.*s", _PATH_DEV, sz, line);
  91         if (stat(ttybuf, &sb) == 0) {
  92                 return (0);
  93         } else
  94                 return (-1);
  95 }
  96
  97 int
  98 main(int argc, char *argv[])
  99 {
 100         struct iovec iov;
 101         struct utmp utmp;
 102         int ch;
 103         int ingroup;
 104         FILE *fp;
 105         struct wallgroup *g;
 106         struct group *grp;
 107         char **np;
 108         const char *p;
 109         struct passwd *pw;
 110         char line[sizeof(utmp.ut_line) + 1];
 111         char username[sizeof(utmp.ut_name) + 1];
 112
 113         (void)setlocale(LC_CTYPE, "");
 114
 115         while ((ch = getopt(argc, argv, "g:n")) != -1)
 116                 switch (ch) {
 117                 case 'n':
 118                         /* undoc option for shutdown: suppress banner */
 119                         if (geteuid() == 0)
 120                                 nobanner = 1;
 121                         break;
 122                 case 'g':
 123                         g = (struct wallgroup *)malloc(sizeof *g);
 124                         g->next = grouplist;
 125                         g->name = optarg;
 126                         g->gid = -1;
 127                         grouplist = g;
 128                         break;
 129                 case '?':
 130                 default:
 131                         usage();
 132                 }
 133         argc -= optind;
 134         argv += optind;
 135         if (argc > 1)
 136                 usage();
 137
 138         for (g = grouplist; g; g = g->next) {
 139                 grp = getgrnam(g->name);
 140                 if (grp != NULL)
 141                         g->gid = grp->gr_gid;
 142                 else
 143                         warnx("%s: no such group", g->name);
 144         }
 145
 146         makemsg(*argv);
 147
 148         if (!(fp = fopen(_PATH_UTMP, "r")))
 149                 err(1, "cannot read %s", _PATH_UTMP);
 150         iov.iov_base = mbuf;
 151         iov.iov_len = mbufsize;
 152         /* NOSTRICT */
 153         while (fread((char *)&utmp, sizeof(utmp), 1, fp) == 1) {
 154                 if (!utmp.ut_name[0])
 155                         continue;
 156                 if (ttystat(utmp.ut_line, UT_LINESIZE) != 0)
 157                         continue;
 158                 if (grouplist) {
 159                         ingroup = 0;
 160                         strlcpy(username, utmp.ut_name, sizeof(utmp.ut_name));
 161                         pw = getpwnam(username);
 162                         if (!pw)
 163                                 continue;
 164                         for (g = grouplist; g && ingroup == 0; g = g->next) {
 165                                 if (g->gid == (gid_t)-1)
 166                                         continue;
 167                                 if (g->gid == pw->pw_gid)
 168                                         ingroup = 1;
 169                                 else if ((grp = getgrgid(g->gid)) != NULL) {
 170                                         for (np = grp->gr_mem; *np; np++) {
 171                                                 if (strcmp(*np, username) == 0) {
 172                                                         ingroup = 1;
 173                                                         break;
 174                                                 }
 175                                         }
 176                                 }
 177                         }
 178                         if (ingroup == 0)
 179                                 continue;
 180                 }
 181                 strncpy(line, utmp.ut_line, sizeof(utmp.ut_line));
 182                 line[sizeof(utmp.ut_line)] = '\0';
 183                 if ((p = ttymsg(&iov, 1, line, 60*5)) != NULL)
 184                         warnx("%s", p);
 185         }
 186         exit(0);
 187 }
 188
 189 static void
 190 usage()
 191 {
 192         (void)fprintf(stderr, "usage: wall [-g group] [file]\n");
 193         exit(1);
 194 }
 195
 196 void
 197 makemsg(char *fname)
 198 {
 199         int cnt;
 200         unsigned char ch;
 201         struct tm *lt;
 202         struct passwd *pw;
 203         struct stat sbuf;
 204         time_t now;
 205         FILE *fp;
 206         int fd;
 207         char *p, hostname[MAXHOSTNAMELEN], lbuf[256], tmpname[64];
 208         const char *tty;
 209         const char *whom;
 210         gid_t egid;
 211
 212         (void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
 213         if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
 214                 err(1, "can't open temporary file");
 215         (void)unlink(tmpname);
 216
 217         if (!nobanner) {
 218                 tty = ttyname(STDERR_FILENO);
 219                 if (tty == NULL)
 220                         tty = "no tty";
 221
 222                 if (!(whom = getlogin()))
 223                         whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
 224                 (void)gethostname(hostname, sizeof(hostname));
 225                 (void)time(&now);
 226                 lt = localtime(&now);
 227
 228                 /*
 229                  * all this stuff is to blank out a square for the message;
 230                  * we wrap message lines at column 79, not 80, because some
 231                  * terminals wrap after 79, some do not, and we can't tell.
 232                  * Which means that we may leave a non-blank character
 233                  * in column 80, but that can't be helped.
 234                  */
 235                 (void)fprintf(fp, "\r%79s\r\n", " ");
 236                 (void)snprintf(lbuf, sizeof(lbuf),
 237                     "Broadcast Message from %s@%s",
 238                     whom, hostname);
 239                 (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
 240                 (void)snprintf(lbuf, sizeof(lbuf),
 241                     "        (%s) at %d:%02d %s...", tty,
 242                     lt->tm_hour, lt->tm_min, lt->tm_zone);
 243                 (void)fprintf(fp, "%-79.79s\r\n", lbuf);
 244         }
 245         (void)fprintf(fp, "%79s\r\n", " ");
 246
 247         if (fname) {
 248                 egid = getegid();
 249                 setegid(getgid());
 250                 if (freopen(fname, "r", stdin) == NULL)
 251                         err(1, "can't read %s", fname);
 252                 setegid(egid);
 253         }
 254         while (fgets(lbuf, sizeof(lbuf), stdin)) {
 255                 for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
 256                         if (ch == '\r') {
 257                                 putc('\r', fp);
 258                                 cnt = 0;
 259                                 continue;
 260                         } else if (ch == '\n') {
 261                                 for (; cnt < 79; ++cnt)
 262                                         putc(' ', fp);
 263                                 putc('\r', fp);
 264                                 putc('\n', fp);
 265                                 break;
 266                         }
 267                         if (cnt == 79) {
 268                                 putc('\r', fp);
 269                                 putc('\n', fp);
 270                                 cnt = 0;
 271                         }
 272                         if (((ch & 0x80) && ch < 0xA0) ||
 273                                    /* disable upper controls */
 274                                    (!isprint(ch) && !isspace(ch) &&
 275                                     ch != '\a' && ch != '\b')
 276                                   ) {
 277                                 if (ch & 0x80) {
 278                                         ch &= 0x7F;
 279                                         putc('M', fp);
 280                                         if (++cnt == 79) {
 281                                                 putc('\r', fp);
 282                                                 putc('\n', fp);
 283                                                 cnt = 0;
 284                                         }
 285                                         putc('-', fp);
 286                                         if (++cnt == 79) {
 287                                                 putc('\r', fp);
 288                                                 putc('\n', fp);
 289                                                 cnt = 0;
 290                                         }
 291                                 }
 292                                 if (iscntrl(ch)) {
 293                                         ch ^= 040;
 294                                         putc('^', fp);
 295                                         if (++cnt == 79) {
 296                                                 putc('\r', fp);
 297                                                 putc('\n', fp);
 298                                                 cnt = 0;
 299                                         }
 300                                 }
 301                         }
 302                         putc(ch, fp);
 303                 }
 304         }
 305         (void)fprintf(fp, "%79s\r\n", " ");
 306         rewind(fp);
 307
 308         if (fstat(fd, &sbuf))
 309                 err(1, "can't stat temporary file");
 310         mbufsize = sbuf.st_size;
 311         if (!(mbuf = malloc((u_int)mbufsize)))
 312                 err(1, "out of memory");
 313         if ((int)fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
 314                 err(1, "can't read temporary file");
 315         (void)close(fd);
 316 }