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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#) Copyright (c) 1988, 1990, 1993 The Regents of the University of California.  All rights reserved.
  30  * @(#)wall.c   8.2 (Berkeley) 11/16/93
  31  * $FreeBSD: src/usr.bin/wall/wall.c,v 1.13.2.6 2001/10/18 08:08:17 des Exp $
  32  * $DragonFly: src/usr.bin/wall/wall.c,v 1.4 2005/08/31 16:27:53 liamfoy Exp $
  33  */
  34
  35 /*
  36  * This program is not related to David Wall, whose Stanford Ph.D. thesis
  37  * is entitled "Mechanisms for Broadcast and Selective Broadcast".
  38  */
  39
  40 #include <sys/param.h>
  41 #include <sys/stat.h>
  42 #include <sys/uio.h>
  43
  44 #include <ctype.h>
  45 #include <err.h>
  46 #include <grp.h>
  47 #include <locale.h>
  48 #include <paths.h>
  49 #include <pwd.h>
  50 #include <stdio.h>
  51 #include <stdlib.h>
  52 #include <string.h>
  53 #include <time.h>
  54 #include <unistd.h>
  55 #include "utmpentry.h"
  56
  57 #include "ttymsg.h"
  58
  59 static void makemsg(char *);
  60 static void usage(void);
  61
  62 struct wallgroup {
  63         struct wallgroup *next;
  64         char            *name;
  65         gid_t           gid;
  66 } *grouplist;
  67 int nobanner;
  68 int mbufsize;
  69 char *mbuf;
  70
  71 int
  72 main(int argc, char *argv[])
  73 {
  74         struct iovec iov;
  75         struct utmpentry *ep = NULL;    /* avoid gcc warnings */
  76         int ch;
  77         int ingroup;
  78         struct wallgroup *g;
  79         struct group *grp;
  80         char **np;
  81         const char *p;
  82         struct passwd *pw;
  83
  84         (void)setlocale(LC_CTYPE, "");
  85
  86         while ((ch = getopt(argc, argv, "g:n")) != -1)
  87                 switch (ch) {
  88                 case 'n':
  89                         /* undoc option for shutdown: suppress banner */
  90                         if (geteuid() == 0)
  91                                 nobanner = 1;
  92                         break;
  93                 case 'g':
  94                         g = (struct wallgroup *)malloc(sizeof *g);
  95                         g->next = grouplist;
  96                         g->name = optarg;
  97                         g->gid = -1;
  98                         grouplist = g;
  99                         break;
 100                 case '?':
 101                 default:
 102                         usage();
 103                 }
 104         argc -= optind;
 105         argv += optind;
 106         if (argc > 1)
 107                 usage();
 108
 109         for (g = grouplist; g; g = g->next) {
 110                 grp = getgrnam(g->name);
 111                 if (grp != NULL)
 112                         g->gid = grp->gr_gid;
 113                 else
 114                         warnx("%s: no such group", g->name);
 115         }
 116
 117         makemsg(*argv);
 118
 119         iov.iov_base = mbuf;
 120         iov.iov_len = mbufsize;
 121
 122         getutentries(NULL, &ep);
 123         /* NOSTRICT */
 124         for (; ep; ep = ep->next) {
 125                 if (grouplist) {
 126                         ingroup = 0;
 127                         pw = getpwnam(ep->name);
 128                         if (!pw)
 129                                 continue;
 130                         for (g = grouplist; g && ingroup == 0; g = g->next) {
 131                                 if (g->gid == (gid_t)-1)
 132                                         continue;
 133                                 if (g->gid == pw->pw_gid)
 134                                         ingroup = 1;
 135                                 else if ((grp = getgrgid(g->gid)) != NULL) {
 136                                         for (np = grp->gr_mem; *np; np++) {
 137                                                 if (strcmp(*np, ep->name) == 0) {
 138                                                         ingroup = 1;
 139                                                         break;
 140                                                 }
 141                                         }
 142                                 }
 143                         }
 144                         if (ingroup == 0)
 145                                 continue;
 146                 }
 147                 /* skip [xgk]dm/xserver entries (":0", ":1", etc.) */
 148                 if (ep->line[0] == ':' && isdigit((unsigned char)ep->line[1]))
 149                         continue;
 150
 151                 if ((p = ttymsg(&iov, 1, ep->line, 60*5)) != NULL)
 152                         warnx("%s", p);
 153         }
 154         exit(0);
 155 }
 156
 157 static void
 158 usage(void)
 159 {
 160         (void)fprintf(stderr, "usage: wall [-g group] [file]\n");
 161         exit(1);
 162 }
 163
 164 void
 165 makemsg(char *fname)
 166 {
 167         int cnt;
 168         unsigned char ch;
 169         struct tm *lt;
 170         struct passwd *pw;
 171         struct stat sbuf;
 172         time_t now;
 173         FILE *fp;
 174         int fd;
 175         char *p, hostname[MAXHOSTNAMELEN], lbuf[256], tmpname[MAXPATHLEN];
 176         const char *tty;
 177         const char *whom;
 178         gid_t egid;
 179
 180         (void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
 181         if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
 182                 err(1, "can't open temporary file");
 183         (void)unlink(tmpname);
 184
 185         if (!nobanner) {
 186                 tty = ttyname(STDERR_FILENO);
 187                 if (tty == NULL)
 188                         tty = "no tty";
 189
 190                 if (!(whom = getlogin()))
 191                         whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
 192                 (void)gethostname(hostname, sizeof(hostname));
 193                 (void)time(&now);
 194                 lt = localtime(&now);
 195
 196                 /*
 197                  * all this stuff is to blank out a square for the message;
 198                  * we wrap message lines at column 79, not 80, because some
 199                  * terminals wrap after 79, some do not, and we can't tell.
 200                  * Which means that we may leave a non-blank character
 201                  * in column 80, but that can't be helped.
 202                  */
 203                 (void)fprintf(fp, "\r%79s\r\n", " ");
 204                 (void)snprintf(lbuf, sizeof(lbuf),
 205                     "Broadcast Message from %s@%s",
 206                     whom, hostname);
 207                 (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
 208                 (void)snprintf(lbuf, sizeof(lbuf),
 209                     "        (%s) at %d:%02d %s...", tty,
 210                     lt->tm_hour, lt->tm_min, lt->tm_zone);
 211                 (void)fprintf(fp, "%-79.79s\r\n", lbuf);
 212         }
 213         (void)fprintf(fp, "%79s\r\n", " ");
 214
 215         if (fname) {
 216                 egid = getegid();
 217                 setegid(getgid());
 218                 if (freopen(fname, "r", stdin) == NULL)
 219                         err(1, "can't read %s", fname);
 220                 setegid(egid);
 221         }
 222         while (fgets(lbuf, sizeof(lbuf), stdin))
 223                 for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
 224                         if (ch == '\r') {
 225                                 cnt = 0;
 226                         } else if (cnt == 79 || ch == '\n') {
 227                                 for (; cnt < 79; ++cnt)
 228                                         putc(' ', fp);
 229                                 putc('\r', fp);
 230                                 putc('\n', fp);
 231                                 cnt = 0;
 232                         } else if (((ch & 0x80) && ch < 0xA0) ||
 233                                    /* disable upper controls */
 234                                    (!isprint(ch) && !isspace(ch) &&
 235                                     ch != '\a' && ch != '\b')
 236                                   ) {
 237                                 if (ch & 0x80) {
 238                                         ch &= 0x7F;
 239                                         putc('M', fp);
 240                                         if (++cnt == 79) {
 241                                                 putc('\r', fp);
 242                                                 putc('\n', fp);
 243                                                 cnt = 0;
 244                                         }
 245                                         putc('-', fp);
 246                                         if (++cnt == 79) {
 247                                                 putc('\r', fp);
 248                                                 putc('\n', fp);
 249                                                 cnt = 0;
 250                                         }
 251                                 }
 252                                 if (iscntrl(ch)) {
 253                                         ch ^= 040;
 254                                         putc('^', fp);
 255                                         if (++cnt == 79) {
 256                                                 putc('\r', fp);
 257                                                 putc('\n', fp);
 258                                                 cnt = 0;
 259                                         }
 260                                 }
 261                                 putc(ch, fp);
 262                         } else {
 263                                 putc(ch, fp);
 264                         }
 265                 }
 266         (void)fprintf(fp, "%79s\r\n", " ");
 267         rewind(fp);
 268
 269         if (fstat(fd, &sbuf))
 270                 err(1, "can't stat temporary file");
 271         mbufsize = sbuf.st_size;
 272         if (!(mbuf = malloc((u_int)mbufsize)))
 273                 err(1, "out of memory");
 274         if ((int)fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
 275                 err(1, "can't read temporary file");
 276         (void)close(fd);
 277 }