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 int
  85 main(int argc, char *argv[])
  86 {
  87         struct iovec iov;
  88         struct utmp utmp;
  89         int ch;
  90         int ingroup;
  91         FILE *fp;
  92         struct wallgroup *g;
  93         struct group *grp;
  94         char **np;
  95         const char *p;
  96         struct passwd *pw;
  97         char line[sizeof(utmp.ut_line) + 1];
  98         char username[sizeof(utmp.ut_name) + 1];
  99
 100         (void)setlocale(LC_CTYPE, "");
 101
 102         while ((ch = getopt(argc, argv, "g:n")) != -1)
 103                 switch (ch) {
 104                 case 'n':
 105                         /* undoc option for shutdown: suppress banner */
 106                         if (geteuid() == 0)
 107                                 nobanner = 1;
 108                         break;
 109                 case 'g':
 110                         g = (struct wallgroup *)malloc(sizeof *g);
 111                         g->next = grouplist;
 112                         g->name = optarg;
 113                         g->gid = -1;
 114                         grouplist = g;
 115                         break;
 116                 case '?':
 117                 default:
 118                         usage();
 119                 }
 120         argc -= optind;
 121         argv += optind;
 122         if (argc > 1)
 123                 usage();
 124
 125         for (g = grouplist; g; g = g->next) {
 126                 grp = getgrnam(g->name);
 127                 if (grp != NULL)
 128                         g->gid = grp->gr_gid;
 129                 else
 130                         warnx("%s: no such group", g->name);
 131         }
 132
 133         makemsg(*argv);
 134
 135         if (!(fp = fopen(_PATH_UTMP, "r")))
 136                 err(1, "cannot read %s", _PATH_UTMP);
 137         iov.iov_base = mbuf;
 138         iov.iov_len = mbufsize;
 139         /* NOSTRICT */
 140         while (fread((char *)&utmp, sizeof(utmp), 1, fp) == 1) {
 141                 if (!utmp.ut_name[0])
 142                         continue;
 143                 if (grouplist) {
 144                         ingroup = 0;
 145                         strlcpy(username, utmp.ut_name, sizeof(utmp.ut_name));
 146                         pw = getpwnam(username);
 147                         if (!pw)
 148                                 continue;
 149                         for (g = grouplist; g && ingroup == 0; g = g->next) {
 150                                 if (g->gid == (gid_t)-1)
 151                                         continue;
 152                                 if (g->gid == pw->pw_gid)
 153                                         ingroup = 1;
 154                                 else if ((grp = getgrgid(g->gid)) != NULL) {
 155                                         for (np = grp->gr_mem; *np; np++) {
 156                                                 if (strcmp(*np, username) == 0) {
 157                                                         ingroup = 1;
 158                                                         break;
 159                                                 }
 160                                         }
 161                                 }
 162                         }
 163                         if (ingroup == 0)
 164                                 continue;
 165                 }
 166                 strncpy(line, utmp.ut_line, sizeof(utmp.ut_line));
 167                 line[sizeof(utmp.ut_line)] = '\0';
 168                 if ((p = ttymsg(&iov, 1, line, 60*5)) != NULL)
 169                         warnx("%s", p);
 170         }
 171         exit(0);
 172 }
 173
 174 static void
 175 usage()
 176 {
 177         (void)fprintf(stderr, "usage: wall [-g group] [file]\n");
 178         exit(1);
 179 }
 180
 181 void
 182 makemsg(char *fname)
 183 {
 184         int cnt;
 185         unsigned char ch;
 186         struct tm *lt;
 187         struct passwd *pw;
 188         struct stat sbuf;
 189         time_t now;
 190         FILE *fp;
 191         int fd;
 192         char *p, hostname[MAXHOSTNAMELEN], lbuf[256], tmpname[64];
 193         const char *tty;
 194         const char *whom;
 195         gid_t egid;
 196
 197         (void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
 198         if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
 199                 err(1, "can't open temporary file");
 200         (void)unlink(tmpname);
 201
 202         if (!nobanner) {
 203                 tty = ttyname(STDERR_FILENO);
 204                 if (tty == NULL)
 205                         tty = "no tty";
 206
 207                 if (!(whom = getlogin()))
 208                         whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
 209                 (void)gethostname(hostname, sizeof(hostname));
 210                 (void)time(&now);
 211                 lt = localtime(&now);
 212
 213                 /*
 214                  * all this stuff is to blank out a square for the message;
 215                  * we wrap message lines at column 79, not 80, because some
 216                  * terminals wrap after 79, some do not, and we can't tell.
 217                  * Which means that we may leave a non-blank character
 218                  * in column 80, but that can't be helped.
 219                  */
 220                 (void)fprintf(fp, "\r%79s\r\n", " ");
 221                 (void)snprintf(lbuf, sizeof(lbuf),
 222                     "Broadcast Message from %s@%s",
 223                     whom, hostname);
 224                 (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
 225                 (void)snprintf(lbuf, sizeof(lbuf),
 226                     "        (%s) at %d:%02d %s...", tty,
 227                     lt->tm_hour, lt->tm_min, lt->tm_zone);
 228                 (void)fprintf(fp, "%-79.79s\r\n", lbuf);
 229         }
 230         (void)fprintf(fp, "%79s\r\n", " ");
 231
 232         if (fname) {
 233                 egid = getegid();
 234                 setegid(getgid());
 235                 if (freopen(fname, "r", stdin) == NULL)
 236                         err(1, "can't read %s", fname);
 237                 setegid(egid);
 238         }
 239         while (fgets(lbuf, sizeof(lbuf), stdin))
 240                 for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
 241                         if (ch == '\r') {
 242                                 cnt = 0;
 243                         } else if (cnt == 79 || ch == '\n') {
 244                                 for (; cnt < 79; ++cnt)
 245                                         putc(' ', fp);
 246                                 putc('\r', fp);
 247                                 putc('\n', fp);
 248                                 cnt = 0;
 249                         } else if (((ch & 0x80) && ch < 0xA0) ||
 250                                    /* disable upper controls */
 251                                    (!isprint(ch) && !isspace(ch) &&
 252                                     ch != '\a' && ch != '\b')
 253                                   ) {
 254                                 if (ch & 0x80) {
 255                                         ch &= 0x7F;
 256                                         putc('M', fp);
 257                                         if (++cnt == 79) {
 258                                                 putc('\r', fp);
 259                                                 putc('\n', fp);
 260                                                 cnt = 0;
 261                                         }
 262                                         putc('-', fp);
 263                                         if (++cnt == 79) {
 264                                                 putc('\r', fp);
 265                                                 putc('\n', fp);
 266                                                 cnt = 0;
 267                                         }
 268                                 }
 269                                 if (iscntrl(ch)) {
 270                                         ch ^= 040;
 271                                         putc('^', fp);
 272                                         if (++cnt == 79) {
 273                                                 putc('\r', fp);
 274                                                 putc('\n', fp);
 275                                                 cnt = 0;
 276                                         }
 277                                 }
 278                                 putc(ch, fp);
 279                         } else {
 280                                 putc(ch, fp);
 281                         }
 282                 }
 283         (void)fprintf(fp, "%79s\r\n", " ");
 284         rewind(fp);
 285
 286         if (fstat(fd, &sbuf))
 287                 err(1, "can't stat temporary file");
 288         mbufsize = sbuf.st_size;
 289         if (!(mbuf = malloc((u_int)mbufsize)))
 290                 err(1, "out of memory");
 291         if ((int)fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
 292                 err(1, "can't read temporary file");
 293         (void)close(fd);
 294 }