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 1.4 2005/08/31 16:27:53 liamfoy 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 struct wallgroup {
  67         struct wallgroup *next;
  68         char            *name;
  69         gid_t           gid;
  70 } *grouplist;
  71 int nobanner;
  72 int mbufsize;
  73 char *mbuf;
  74
  75 int
  76 main(int argc, char *argv[])
  77 {
  78         struct iovec iov;
  79         struct utmp utmp;
  80         int ch;
  81         int ingroup;
  82         FILE *fp;
  83         struct wallgroup *g;
  84         struct group *grp;
  85         char **np;
  86         const char *p;
  87         struct passwd *pw;
  88         char line[sizeof(utmp.ut_line) + 1];
  89         char username[sizeof(utmp.ut_name) + 1];
  90
  91         (void)setlocale(LC_CTYPE, "");
  92
  93         while ((ch = getopt(argc, argv, "g:n")) != -1)
  94                 switch (ch) {
  95                 case 'n':
  96                         /* undoc option for shutdown: suppress banner */
  97                         if (geteuid() == 0)
  98                                 nobanner = 1;
  99                         break;
 100                 case 'g':
 101                         g = (struct wallgroup *)malloc(sizeof *g);
 102                         g->next = grouplist;
 103                         g->name = optarg;
 104                         g->gid = -1;
 105                         grouplist = g;
 106                         break;
 107                 case '?':
 108                 default:
 109                         usage();
 110                 }
 111         argc -= optind;
 112         argv += optind;
 113         if (argc > 1)
 114                 usage();
 115
 116         for (g = grouplist; g; g = g->next) {
 117                 grp = getgrnam(g->name);
 118                 if (grp != NULL)
 119                         g->gid = grp->gr_gid;
 120                 else
 121                         warnx("%s: no such group", g->name);
 122         }
 123
 124         makemsg(*argv);
 125
 126         if (!(fp = fopen(_PATH_UTMP, "r")))
 127                 err(1, "cannot read %s", _PATH_UTMP);
 128         iov.iov_base = mbuf;
 129         iov.iov_len = mbufsize;
 130         /* NOSTRICT */
 131         while (fread((char *)&utmp, sizeof(utmp), 1, fp) == 1) {
 132                 if (!utmp.ut_name[0])
 133                         continue;
 134                 if (grouplist) {
 135                         ingroup = 0;
 136                         strlcpy(username, utmp.ut_name, sizeof(utmp.ut_name));
 137                         pw = getpwnam(username);
 138                         if (!pw)
 139                                 continue;
 140                         for (g = grouplist; g && ingroup == 0; g = g->next) {
 141                                 if (g->gid == (gid_t)-1)
 142                                         continue;
 143                                 if (g->gid == pw->pw_gid)
 144                                         ingroup = 1;
 145                                 else if ((grp = getgrgid(g->gid)) != NULL) {
 146                                         for (np = grp->gr_mem; *np; np++) {
 147                                                 if (strcmp(*np, username) == 0) {
 148                                                         ingroup = 1;
 149                                                         break;
 150                                                 }
 151                                         }
 152                                 }
 153                         }
 154                         if (ingroup == 0)
 155                                 continue;
 156                 }
 157                 strncpy(line, utmp.ut_line, sizeof(utmp.ut_line));
 158                 line[sizeof(utmp.ut_line)] = '\0';
 159                 if ((p = ttymsg(&iov, 1, line, 60*5)) != NULL)
 160                         warnx("%s", p);
 161         }
 162         exit(0);
 163 }
 164
 165 static void
 166 usage(void)
 167 {
 168         (void)fprintf(stderr, "usage: wall [-g group] [file]\n");
 169         exit(1);
 170 }
 171
 172 void
 173 makemsg(char *fname)
 174 {
 175         int cnt;
 176         unsigned char ch;
 177         struct tm *lt;
 178         struct passwd *pw;
 179         struct stat sbuf;
 180         time_t now;
 181         FILE *fp;
 182         int fd;
 183         char *p, hostname[MAXHOSTNAMELEN], lbuf[256], tmpname[MAXPATHLEN];
 184         const char *tty;
 185         const char *whom;
 186         gid_t egid;
 187
 188         (void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
 189         if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
 190                 err(1, "can't open temporary file");
 191         (void)unlink(tmpname);
 192
 193         if (!nobanner) {
 194                 tty = ttyname(STDERR_FILENO);
 195                 if (tty == NULL)
 196                         tty = "no tty";
 197
 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
 204                 /*
 205                  * all this stuff is to blank out a square for the message;
 206                  * we wrap message lines at column 79, not 80, because some
 207                  * terminals wrap after 79, some do not, and we can't tell.
 208                  * Which means that we may leave a non-blank character
 209                  * in column 80, but that can't be helped.
 210                  */
 211                 (void)fprintf(fp, "\r%79s\r\n", " ");
 212                 (void)snprintf(lbuf, sizeof(lbuf),
 213                     "Broadcast Message from %s@%s",
 214                     whom, hostname);
 215                 (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
 216                 (void)snprintf(lbuf, sizeof(lbuf),
 217                     "        (%s) at %d:%02d %s...", tty,
 218                     lt->tm_hour, lt->tm_min, lt->tm_zone);
 219                 (void)fprintf(fp, "%-79.79s\r\n", lbuf);
 220         }
 221         (void)fprintf(fp, "%79s\r\n", " ");
 222
 223         if (fname) {
 224                 egid = getegid();
 225                 setegid(getgid());
 226                 if (freopen(fname, "r", stdin) == NULL)
 227                         err(1, "can't read %s", fname);
 228                 setegid(egid);
 229         }
 230         while (fgets(lbuf, sizeof(lbuf), stdin))
 231                 for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
 232                         if (ch == '\r') {
 233                                 cnt = 0;
 234                         } else if (cnt == 79 || ch == '\n') {
 235                                 for (; cnt < 79; ++cnt)
 236                                         putc(' ', fp);
 237                                 putc('\r', fp);
 238                                 putc('\n', fp);
 239                                 cnt = 0;
 240                         } else if (((ch & 0x80) && ch < 0xA0) ||
 241                                    /* disable upper controls */
 242                                    (!isprint(ch) && !isspace(ch) &&
 243                                     ch != '\a' && ch != '\b')
 244                                   ) {
 245                                 if (ch & 0x80) {
 246                                         ch &= 0x7F;
 247                                         putc('M', fp);
 248                                         if (++cnt == 79) {
 249                                                 putc('\r', fp);
 250                                                 putc('\n', fp);
 251                                                 cnt = 0;
 252                                         }
 253                                         putc('-', fp);
 254                                         if (++cnt == 79) {
 255                                                 putc('\r', fp);
 256                                                 putc('\n', fp);
 257                                                 cnt = 0;
 258                                         }
 259                                 }
 260                                 if (iscntrl(ch)) {
 261                                         ch ^= 040;
 262                                         putc('^', fp);
 263                                         if (++cnt == 79) {
 264                                                 putc('\r', fp);
 265                                                 putc('\n', fp);
 266                                                 cnt = 0;
 267                                         }
 268                                 }
 269                                 putc(ch, fp);
 270                         } else {
 271                                 putc(ch, fp);
 272                         }
 273                 }
 274         (void)fprintf(fp, "%79s\r\n", " ");
 275         rewind(fp);
 276
 277         if (fstat(fd, &sbuf))
 278                 err(1, "can't stat temporary file");
 279         mbufsize = sbuf.st_size;
 280         if (!(mbuf = malloc((u_int)mbufsize)))
 281                 err(1, "out of memory");
 282         if ((int)fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
 283                 err(1, "can't read temporary file");
 284         (void)close(fd);
 285 }