login-utils/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  * Modified Sun Mar 12 10:34:34 1995, faith@cs.unc.edu, for Linux
  34  */
  35
  36 /*
  37  * This program is not related to David Wall, whose Stanford Ph.D. thesis
  38  * is entitled "Mechanisms for Broadcast and Selective Broadcast".
  39  *
  40  * 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@misiek.eu.org>
  41  * - added Native Language Support
  42  *
  43  */
  44
  45 #include <sys/param.h>
  46 #include <sys/stat.h>
  47 #include <sys/time.h>
  48 #include <sys/uio.h>
  49
  50 #include <paths.h>
  51 #include <ctype.h>
  52 #include <pwd.h>
  53 #include <stdio.h>
  54 #include <stdlib.h>
  55 #include <string.h>
  56 #include <unistd.h>
  57 #include <utmp.h>
  58
  59 #include "nls.h"
  60 #include "ttymsg.h"
  61 #include "pathnames.h"
  62 #include "carefulputc.h"
  63
  64 void    makemsg __P((char *));
  65
  66 #define IGNOREUSER      "sleeper"
  67
  68 int nobanner;
  69 int mbufsize;
  70 char *mbuf;
  71
  72 char *progname = "wall";
  73
  74 int
  75 main(int argc, char **argv) {
  76         extern int optind;
  77         int ch;
  78         struct iovec iov;
  79         struct utmp *utmpptr;
  80         char *p;
  81         char line[sizeof(utmpptr->ut_line) + 1];
  82
  83         setlocale(LC_ALL, "");
  84         bindtextdomain(PACKAGE, LOCALEDIR);
  85         textdomain(PACKAGE);
  86
  87         progname = argv[0];
  88         p = rindex(progname, '/');
  89         if (p)
  90              progname = p+1;
  91
  92         while ((ch = getopt(argc, argv, "n")) != EOF)
  93                 switch (ch) {
  94                 case 'n':
  95                         /* undoc option for shutdown: suppress banner */
  96                         if (geteuid() == 0)
  97                                 nobanner = 1;
  98                         break;
  99                 case '?':
 100                 default:
 101 usage:
 102                         (void)fprintf(stderr, _("usage: %s [file]\n"), progname);
 103                         exit(1);
 104                 }
 105         argc -= optind;
 106         argv += optind;
 107         if (argc > 1)
 108                 goto usage;
 109
 110         makemsg(*argv);
 111
 112         setutent();
 113
 114         iov.iov_base = mbuf;
 115         iov.iov_len = mbufsize;
 116         while((utmpptr = getutent())) {
 117                 if (!utmpptr->ut_name[0] ||
 118                     !strncmp(utmpptr->ut_name, IGNOREUSER, sizeof(utmpptr->ut_name)))
 119                         continue;
 120 #ifdef USER_PROCESS
 121                 if (utmpptr->ut_type != USER_PROCESS)
 122                         continue;
 123 #endif
 124                 strncpy(line, utmpptr->ut_line, sizeof(utmpptr->ut_line));
 125                 line[sizeof(utmpptr->ut_line)-1] = '\0';
 126                 if ((p = ttymsg(&iov, 1, line, 60*5)) != NULL)
 127                         (void)fprintf(stderr, "%s: %s\n", progname, p);
 128         }
 129         endutent();
 130         exit(0);
 131 }
 132
 133 void
 134 makemsg(fname)
 135         char *fname;
 136 {
 137         register int ch, cnt;
 138         struct tm *lt;
 139         struct passwd *pw;
 140         struct stat sbuf;
 141         time_t now;
 142         FILE *fp;
 143         int fd;
 144         char *p, *whom, *where, hostname[MAXHOSTNAMELEN],
 145                 lbuf[MAXHOSTNAMELEN + 320],
 146                 tmpname[sizeof(_PATH_TMP) + 20];
 147
 148         (void)sprintf(tmpname, "%s/wall.XXXXXX", _PATH_TMP);
 149         if (!(fd = mkstemp(tmpname)) || !(fp = fdopen(fd, "r+"))) {
 150                 (void)fprintf(stderr, _("%s: can't open temporary file.\n"), progname);
 151                 exit(1);
 152         }
 153         (void)unlink(tmpname);
 154
 155         if (!nobanner) {
 156                 if (!(whom = getlogin()) || !*whom)
 157                         whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
 158                 if (!whom || strlen(whom) > 100)
 159                         whom = "someone";
 160                 where = ttyname(2);
 161                 if (!where || strlen(where) > 100)
 162                         where = "somewhere";
 163                 (void)gethostname(hostname, sizeof(hostname));
 164                 (void)time(&now);
 165                 lt = localtime(&now);
 166
 167                 /*
 168                  * all this stuff is to blank out a square for the message;
 169                  * we wrap message lines at column 79, not 80, because some
 170                  * terminals wrap after 79, some do not, and we can't tell.
 171                  * Which means that we may leave a non-blank character
 172                  * in column 80, but that can't be helped.
 173                  */
 174                 /* snprintf is not always available, but the sprintf's here
 175                    will not overflow as long as %d takes at most 100 chars */
 176                 (void)fprintf(fp, "\r%79s\r\n", " ");
 177                 (void)sprintf(lbuf, _("Broadcast Message from %s@%s"),
 178                               whom, hostname);
 179                 (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
 180                 (void)sprintf(lbuf, "        (%s) at %d:%02d ...",
 181                               where, lt->tm_hour, lt->tm_min);
 182                 (void)fprintf(fp, "%-79.79s\r\n", lbuf);
 183         }
 184         (void)fprintf(fp, "%79s\r\n", " ");
 185
 186         if (fname) {
 187                 /*
 188                  * When we are not root, but suid or sgid, refuse to read files
 189                  * (e.g. device files) that the user may not have access to.
 190                  * After all, our invoker can easily do "wall < file"
 191                  * instead of "wall file".
 192                  */
 193                 int uid = getuid();
 194                 if (uid && (uid != geteuid() || getgid() != getegid())) {
 195                         fprintf(stderr, _("%s: will not read %s - use stdin.\n"),
 196                                 progname, fname);
 197                         exit(1);
 198                 }
 199                 if (!freopen(fname, "r", stdin)) {
 200                         fprintf(stderr, _("%s: can't read %s.\n"), progname, fname);
 201                         exit(1);
 202                 }
 203         }
 204
 205         while (fgets(lbuf, sizeof(lbuf), stdin)) {
 206                 for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
 207                         if (cnt == 79 || ch == '\n') {
 208                                 for (; cnt < 79; ++cnt)
 209                                         putc(' ', fp);
 210                                 putc('\r', fp);
 211                                 putc('\n', fp);
 212                                 cnt = 0;
 213                         } else {
 214                                 carefulputc(ch, fp);
 215                         }
 216                 }
 217         }
 218         (void)fprintf(fp, "%79s\r\n", " ");
 219         rewind(fp);
 220
 221         if (fstat(fd, &sbuf)) {
 222                 (void)fprintf(stderr, _("%s: can't stat temporary file.\n"), progname);
 223                 exit(1);
 224         }
 225         mbufsize = sbuf.st_size;
 226         if (!(mbuf = malloc((u_int)mbufsize))) {
 227                 (void)fprintf(stderr, _("%s: Out of memory!\n"), progname);
 228                 exit(1);
 229         }
 230         if (fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize) {
 231                 (void)fprintf(stderr, _("%s: can't read temporary file.\n"), progname);
 232                 exit(1);
 233         }
 234         (void)close(fd);
 235 }