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 #ifndef lint
  35 static const char copyright[] =
  36 "@(#) Copyright (c) 1988, 1990, 1993\n\
  37         The Regents of the University of California.  All rights reserved.\n";
  38 #endif /* not lint */
  39
  40 #ifndef lint
  41 #if 0
  42 static char sccsid[] = "@(#)wall.c      8.2 (Berkeley) 11/16/93";
  43 #endif
  44 static const char rcsid[] =
  45   "$FreeBSD: src/usr.bin/wall/wall.c,v 1.13.2.6 2001/10/18 08:08:17 des Exp $";
  46 #endif /* not lint */
  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 #define IGNOREUSER      "sleeper"
  76
  77 struct wallgroup {
  78         struct wallgroup *next;
  79         char            *name;
  80         gid_t           gid;
  81 } *grouplist;
  82 int nobanner;
  83 int mbufsize;
  84 char *mbuf;
  85
  86 int
  87 main(int argc, char *argv[])
  88 {
  89         struct iovec iov;
  90         struct utmp utmp;
  91         int ch;
  92         int ingroup;
  93         FILE *fp;
  94         struct wallgroup *g;
  95         struct group *grp;
  96         char **np;
  97         const char *p;
  98         struct passwd *pw;
  99         char line[sizeof(utmp.ut_line) + 1];
 100         char username[sizeof(utmp.ut_name) + 1];
 101
 102         (void)setlocale(LC_CTYPE, "");
 103
 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)
 109                                 nobanner = 1;
 110                         break;
 111                 case 'g':
 112                         g = (struct wallgroup *)malloc(sizeof *g);
 113                         g->next = grouplist;
 114                         g->name = optarg;
 115                         g->gid = -1;
 116                         grouplist = g;
 117                         break;
 118                 case '?':
 119                 default:
 120                         usage();
 121                 }
 122         argc -= optind;
 123         argv += optind;
 124         if (argc > 1)
 125                 usage();
 126
 127         for (g = grouplist; g; g = g->next) {
 128                 grp = getgrnam(g->name);
 129                 if (grp != NULL)
 130                         g->gid = grp->gr_gid;
 131                 else
 132                         warnx("%s: no such group", g->name);
 133         }
 134
 135         makemsg(*argv);
 136
 137         if (!(fp = fopen(_PATH_UTMP, "r")))
 138                 err(1, "cannot read %s", _PATH_UTMP);
 139         iov.iov_base = mbuf;
 140         iov.iov_len = mbufsize;
 141         /* NOSTRICT */
 142         while (fread((char *)&utmp, sizeof(utmp), 1, fp) == 1) {
 143                 if (!utmp.ut_name[0] ||
 144                     !strncmp(utmp.ut_name, IGNOREUSER, sizeof(utmp.ut_name)))
 145                         continue;
 146                 if (grouplist) {
 147                         ingroup = 0;
 148                         strlcpy(username, utmp.ut_name, sizeof(utmp.ut_name));
 149                         pw = getpwnam(username);
 150                         if (!pw)
 151                                 continue;
 152                         for (g = grouplist; g && ingroup == 0; g = g->next) {
 153                                 if (g->gid == -1)
 154                                         continue;
 155                                 if (g->gid == pw->pw_gid)
 156                                         ingroup = 1;
 157                                 else if ((grp = getgrgid(g->gid)) != NULL) {
 158                                         for (np = grp->gr_mem; *np; np++) {
 159                                                 if (strcmp(*np, username) == 0) {
 160                                                         ingroup = 1;
 161                                                         break;
 162                                                 }
 163                                         }
 164                                 }
 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 static void
 178 usage()
 179 {
 180         (void)fprintf(stderr, "usage: wall [-g group] [file]\n");
 181         exit(1);
 182 }
 183
 184 void
 185 makemsg(char *fname)
 186 {
 187         int cnt;
 188         unsigned char ch;
 189         struct tm *lt;
 190         struct passwd *pw;
 191         struct stat sbuf;
 192         time_t now;
 193         FILE *fp;
 194         int fd;
 195         char *p, *tty, hostname[MAXHOSTNAMELEN], lbuf[256], tmpname[64];
 196         const char *whom;
 197         gid_t egid;
 198
 199         (void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
 200         if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
 201                 err(1, "can't open temporary file");
 202         (void)unlink(tmpname);
 203
 204         if (!nobanner) {
 205                 tty = ttyname(STDERR_FILENO);
 206                 if (tty == NULL)
 207                         tty = "no tty";
 208
 209                 if (!(whom = getlogin()))
 210                         whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
 211                 (void)gethostname(hostname, sizeof(hostname));
 212                 (void)time(&now);
 213                 lt = localtime(&now);
 214
 215                 /*
 216                  * all this stuff is to blank out a square for the message;
 217                  * we wrap message lines at column 79, not 80, because some
 218                  * terminals wrap after 79, some do not, and we can't tell.
 219                  * Which means that we may leave a non-blank character
 220                  * in column 80, but that can't be helped.
 221                  */
 222                 (void)fprintf(fp, "\r%79s\r\n", " ");
 223                 (void)snprintf(lbuf, sizeof(lbuf),
 224                     "Broadcast Message from %s@%s",
 225                     whom, hostname);
 226                 (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
 227                 (void)snprintf(lbuf, sizeof(lbuf),
 228                     "        (%s) at %d:%02d %s...", tty,
 229                     lt->tm_hour, lt->tm_min, lt->tm_zone);
 230                 (void)fprintf(fp, "%-79.79s\r\n", lbuf);
 231         }
 232         (void)fprintf(fp, "%79s\r\n", " ");
 233
 234         if (fname) {
 235                 egid = getegid();
 236                 setegid(getgid());
 237                 if (freopen(fname, "r", stdin) == NULL)
 238                         err(1, "can't read %s", fname);
 239                 setegid(egid);
 240         }
 241         while (fgets(lbuf, sizeof(lbuf), stdin))
 242                 for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
 243                         if (ch == '\r') {
 244                                 cnt = 0;
 245                         } else if (cnt == 79 || ch == '\n') {
 246                                 for (; cnt < 79; ++cnt)
 247                                         putc(' ', fp);
 248                                 putc('\r', fp);
 249                                 putc('\n', fp);
 250                                 cnt = 0;
 251                         } else if (((ch & 0x80) && ch < 0xA0) ||
 252                                    /* disable upper controls */
 253                                    (!isprint(ch) && !isspace(ch) &&
 254                                     ch != '\a' && ch != '\b')
 255                                   ) {
 256                                 if (ch & 0x80) {
 257                                         ch &= 0x7F;
 258                                         putc('M', fp);
 259                                         if (++cnt == 79) {
 260                                                 putc('\r', fp);
 261                                                 putc('\n', fp);
 262                                                 cnt = 0;
 263                                         }
 264                                         putc('-', fp);
 265                                         if (++cnt == 79) {
 266                                                 putc('\r', fp);
 267                                                 putc('\n', fp);
 268                                                 cnt = 0;
 269                                         }
 270                                 }
 271                                 if (iscntrl(ch)) {
 272                                         ch ^= 040;
 273                                         putc('^', fp);
 274                                         if (++cnt == 79) {
 275                                                 putc('\r', fp);
 276                                                 putc('\n', fp);
 277                                                 cnt = 0;
 278                                         }
 279                                 }
 280                                 putc(ch, fp);
 281                         } else {
 282                                 putc(ch, fp);
 283                         }
 284                 }
 285         (void)fprintf(fp, "%79s\r\n", " ");
 286         rewind(fp);
 287
 288         if (fstat(fd, &sbuf))
 289                 err(1, "can't stat temporary file");
 290         mbufsize = sbuf.st_size;
 291         if (!(mbuf = malloc((u_int)mbufsize)))
 292                 err(1, "out of memory");
 293         if (fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
 294                 err(1, "can't read temporary file");
 295         (void)close(fd);
 296 }