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  * @(#) Copyright (c) 1988, 1990, 1993 The Regents of the University of California.  All rights reserved.
  34  * @(#)wall.c   8.2 (Berkeley) 11/16/93
  35  * $FreeBSD: src/usr.bin/wall/wall.c,v 1.13.2.6 2001/10/18 08:08:17 des Exp $
  36  * $DragonFly: src/usr.bin/wall/wall.c,v 1.2 2003/06/17 04:29:33 dillon Exp $
  37  */
  38
  39 /*
  40  * This program is not related to David Wall, whose Stanford Ph.D. thesis
  41  * is entitled "Mechanisms for Broadcast and Selective Broadcast".
  42  */
  43
  44 #include <sys/param.h>
  45 #include <sys/stat.h>
  46 #include <sys/uio.h>
  47
  48 #include <ctype.h>
  49 #include <err.h>
  50 #include <grp.h>
  51 #include <locale.h>
  52 #include <paths.h>
  53 #include <pwd.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include <time.h>
  58 #include <unistd.h>
  59 #include <utmp.h>
  60
  61 #include "ttymsg.h"
  62
  63 static void makemsg(char *);
  64 static void usage(void);
  65
  66 #define IGNOREUSER      "sleeper"
  67
  68 struct wallgroup {
  69         struct wallgroup *next;
  70         char            *name;
  71         gid_t           gid;
  72 } *grouplist;
  73 int nobanner;
  74 int mbufsize;
  75 char *mbuf;
  76
  77 int
  78 main(int argc, char *argv[])
  79 {
  80         struct iovec iov;
  81         struct utmp utmp;
  82         int ch;
  83         int ingroup;
  84         FILE *fp;
  85         struct wallgroup *g;
  86         struct group *grp;
  87         char **np;
  88         const char *p;
  89         struct passwd *pw;
  90         char line[sizeof(utmp.ut_line) + 1];
  91         char username[sizeof(utmp.ut_name) + 1];
  92
  93         (void)setlocale(LC_CTYPE, "");
  94
  95         while ((ch = getopt(argc, argv, "g:n")) != -1)
  96                 switch (ch) {
  97                 case 'n':
  98                         /* undoc option for shutdown: suppress banner */
  99                         if (geteuid() == 0)
 100                                 nobanner = 1;
 101                         break;
 102                 case 'g':
 103                         g = (struct wallgroup *)malloc(sizeof *g);
 104                         g->next = grouplist;
 105                         g->name = optarg;
 106                         g->gid = -1;
 107                         grouplist = g;
 108                         break;
 109                 case '?':
 110                 default:
 111                         usage();
 112                 }
 113         argc -= optind;
 114         argv += optind;
 115         if (argc > 1)
 116                 usage();
 117
 118         for (g = grouplist; g; g = g->next) {
 119                 grp = getgrnam(g->name);
 120                 if (grp != NULL)
 121                         g->gid = grp->gr_gid;
 122                 else
 123                         warnx("%s: no such group", g->name);
 124         }
 125
 126         makemsg(*argv);
 127
 128         if (!(fp = fopen(_PATH_UTMP, "r")))
 129                 err(1, "cannot read %s", _PATH_UTMP);
 130         iov.iov_base = mbuf;
 131         iov.iov_len = mbufsize;
 132         /* NOSTRICT */
 133         while (fread((char *)&utmp, sizeof(utmp), 1, fp) == 1) {
 134                 if (!utmp.ut_name[0] ||
 135                     !strncmp(utmp.ut_name, IGNOREUSER, sizeof(utmp.ut_name)))
 136                         continue;
 137                 if (grouplist) {
 138                         ingroup = 0;
 139                         strlcpy(username, utmp.ut_name, sizeof(utmp.ut_name));
 140                         pw = getpwnam(username);
 141                         if (!pw)
 142                                 continue;
 143                         for (g = grouplist; g && ingroup == 0; g = g->next) {
 144                                 if (g->gid == -1)
 145                                         continue;
 146                                 if (g->gid == pw->pw_gid)
 147                                         ingroup = 1;
 148                                 else if ((grp = getgrgid(g->gid)) != NULL) {
 149                                         for (np = grp->gr_mem; *np; np++) {
 150                                                 if (strcmp(*np, username) == 0) {
 151                                                         ingroup = 1;
 152                                                         break;
 153                                                 }
 154                                         }
 155                                 }
 156                         }
 157                         if (ingroup == 0)
 158                                 continue;
 159                 }
 160                 strncpy(line, utmp.ut_line, sizeof(utmp.ut_line));
 161                 line[sizeof(utmp.ut_line)] = '\0';
 162                 if ((p = ttymsg(&iov, 1, line, 60*5)) != NULL)
 163                         warnx("%s", p);
 164         }
 165         exit(0);
 166 }
 167
 168 static void
 169 usage()
 170 {
 171         (void)fprintf(stderr, "usage: wall [-g group] [file]\n");
 172         exit(1);
 173 }
 174
 175 void
 176 makemsg(char *fname)
 177 {
 178         int cnt;
 179         unsigned char ch;
 180         struct tm *lt;
 181         struct passwd *pw;
 182         struct stat sbuf;
 183         time_t now;
 184         FILE *fp;
 185         int fd;
 186         char *p, *tty, hostname[MAXHOSTNAMELEN], lbuf[256], tmpname[64];
 187         const char *whom;
 188         gid_t egid;
 189
 190         (void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
 191         if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
 192                 err(1, "can't open temporary file");
 193         (void)unlink(tmpname);
 194
 195         if (!nobanner) {
 196                 tty = ttyname(STDERR_FILENO);
 197                 if (tty == NULL)
 198                         tty = "no tty";
 199
 200                 if (!(whom = getlogin()))
 201                         whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
 202                 (void)gethostname(hostname, sizeof(hostname));
 203                 (void)time(&now);
 204                 lt = localtime(&now);
 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",
 216                     whom, hostname);
 217                 (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
 218                 (void)snprintf(lbuf, sizeof(lbuf),
 219                     "        (%s) at %d:%02d %s...", tty,
 220                     lt->tm_hour, lt->tm_min, lt->tm_zone);
 221                 (void)fprintf(fp, "%-79.79s\r\n", lbuf);
 222         }
 223         (void)fprintf(fp, "%79s\r\n", " ");
 224
 225         if (fname) {
 226                 egid = getegid();
 227                 setegid(getgid());
 228                 if (freopen(fname, "r", stdin) == NULL)
 229                         err(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                         if (ch == '\r') {
 235                                 cnt = 0;
 236                         } else if (cnt == 79 || ch == '\n') {
 237                                 for (; cnt < 79; ++cnt)
 238                                         putc(' ', fp);
 239                                 putc('\r', fp);
 240                                 putc('\n', fp);
 241                                 cnt = 0;
 242                         } else if (((ch & 0x80) && ch < 0xA0) ||
 243                                    /* disable upper controls */
 244                                    (!isprint(ch) && !isspace(ch) &&
 245                                     ch != '\a' && ch != '\b')
 246                                   ) {
 247                                 if (ch & 0x80) {
 248                                         ch &= 0x7F;
 249                                         putc('M', fp);
 250                                         if (++cnt == 79) {
 251                                                 putc('\r', fp);
 252                                                 putc('\n', fp);
 253                                                 cnt = 0;
 254                                         }
 255                                         putc('-', fp);
 256                                         if (++cnt == 79) {
 257                                                 putc('\r', fp);
 258                                                 putc('\n', fp);
 259                                                 cnt = 0;
 260                                         }
 261                                 }
 262                                 if (iscntrl(ch)) {
 263                                         ch ^= 040;
 264                                         putc('^', fp);
 265                                         if (++cnt == 79) {
 266                                                 putc('\r', fp);
 267                                                 putc('\n', fp);
 268                                                 cnt = 0;
 269                                         }
 270                                 }
 271                                 putc(ch, fp);
 272                         } else {
 273                                 putc(ch, fp);
 274                         }
 275                 }
 276         (void)fprintf(fp, "%79s\r\n", " ");
 277         rewind(fp);
 278
 279         if (fstat(fd, &sbuf))
 280                 err(1, "can't stat temporary file");
 281         mbufsize = sbuf.st_size;
 282         if (!(mbuf = malloc((u_int)mbufsize)))
 283                 err(1, "out of memory");
 284         if (fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
 285                 err(1, "can't read temporary file");
 286         (void)close(fd);
 287 }