term-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@pld.ORG.PL>
  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 <errno.h>
  51 #include <paths.h>
  52 #include <ctype.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 #include <getopt.h>
  61
  62 #include "nls.h"
  63 #include "xalloc.h"
  64 #include "strutils.h"
  65 #include "ttymsg.h"
  66 #include "pathnames.h"
  67 #include "carefulputc.h"
  68 #include "c.h"
  69 #include "fileutils.h"
  70 #include "closestream.h"
  71
  72 #define IGNOREUSER      "sleeper"
  73 #define WRITE_TIME_OUT  300             /* in seconds */
  74
  75 /* Function prototypes */
  76 char *makemsg(char *fname, size_t *mbufsize, int print_banner);
  77 static void usage(FILE *out);
  78
  79 static void __attribute__((__noreturn__)) usage(FILE *out)
  80 {
  81         fputs(_("\nUsage:\n"), out);
  82         fprintf(out,
  83                 _(" %s [options] [<file>]\n"),program_invocation_short_name);
  84
  85         fputs(_("\nOptions:\n"), out);
  86         fputs(_(" -n, --nobanner          do not print banner, works only for root\n"
  87                 " -t, --timeout <timeout> write timeout in seconds\n"
  88                 " -V, --version           output version information and exit\n"
  89                 " -h, --help              display this help and exit\n\n"), out);
  90
  91         exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
  92 }
  93
  94 int
  95 main(int argc, char **argv) {
  96         int ch;
  97         struct iovec iov;
  98         struct utmp *utmpptr;
  99         char *p;
 100         char line[sizeof(utmpptr->ut_line) + 1];
 101         int print_banner = TRUE;
 102         char *mbuf;
 103         size_t mbufsize;
 104         unsigned timeout = WRITE_TIME_OUT;
 105
 106         setlocale(LC_ALL, "");
 107         bindtextdomain(PACKAGE, LOCALEDIR);
 108         textdomain(PACKAGE);
 109         atexit(close_stdout);
 110
 111         static const struct option longopts[] = {
 112                 { "nobanner",   no_argument,            0, 'n' },
 113                 { "timeout",    required_argument,      0, 't' },
 114                 { "version",    no_argument,            0, 'V' },
 115                 { "help",       no_argument,            0, 'h' },
 116                 { NULL, 0, 0, 0 }
 117         };
 118
 119         while ((ch = getopt_long(argc, argv, "nt:Vh", longopts, NULL)) != -1) {
 120                 switch (ch) {
 121                 case 'n':
 122                         if (geteuid() == 0)
 123                                 print_banner = FALSE;
 124                         else
 125                                 warnx(_("--nobanner is available only for root"));
 126                         break;
 127                 case 't':
 128                         timeout = strtou32_or_err(optarg, _("invalid timeout argument"));
 129                         if (timeout < 1)
 130                                 errx(EXIT_FAILURE, _("invalid timeout argument: %s"), optarg);
 131                         break;
 132                 case 'V':
 133                         printf(_("%s from %s\n"), program_invocation_short_name,
 134                                                   PACKAGE_STRING);
 135                         exit(EXIT_SUCCESS);
 136                 case 'h':
 137                         usage(stdout);
 138                 default:
 139                         usage(stderr);
 140                 }
 141         }
 142         argc -= optind;
 143         argv += optind;
 144         if (argc > 1)
 145                 usage(stderr);
 146
 147         mbuf = makemsg(*argv, &mbufsize, print_banner);
 148
 149         iov.iov_base = mbuf;
 150         iov.iov_len = mbufsize;
 151         while((utmpptr = getutent())) {
 152                 if (!utmpptr->ut_name[0] ||
 153                     !strncmp(utmpptr->ut_name, IGNOREUSER,
 154                              sizeof(utmpptr->ut_name)))
 155                         continue;
 156 #ifdef USER_PROCESS
 157                 if (utmpptr->ut_type != USER_PROCESS)
 158                         continue;
 159 #endif
 160
 161                 /* Joey Hess reports that use-sessreg in /etc/X11/wdm/
 162                    produces ut_line entries like :0, and a write
 163                    to /dev/:0 fails. */
 164                 if (utmpptr->ut_line[0] == ':')
 165                         continue;
 166
 167                 xstrncpy(line, utmpptr->ut_line, sizeof(utmpptr->ut_line));
 168                 if ((p = ttymsg(&iov, 1, line, timeout)) != NULL)
 169                         warnx("%s", p);
 170         }
 171         endutent();
 172         free(mbuf);
 173         exit(EXIT_SUCCESS);
 174 }
 175
 176 char *
 177 makemsg(char *fname, size_t *mbufsize, int print_banner)
 178 {
 179         register int ch, cnt;
 180         struct tm *lt;
 181         struct passwd *pw;
 182         struct stat sbuf;
 183         time_t now;
 184         FILE *fp;
 185         char *p, *whom, *where, *hostname, *lbuf, *tmpname, *mbuf;
 186         long line_max;
 187
 188         hostname = xmalloc(sysconf(_SC_HOST_NAME_MAX) + 1);
 189         line_max = sysconf(_SC_LINE_MAX);
 190         lbuf = xmalloc(line_max);
 191
 192         if ((fp = xfmkstemp(&tmpname, NULL)) == NULL)
 193                 err(EXIT_FAILURE, _("can't open temporary file"));
 194         unlink(tmpname);
 195         free(tmpname);
 196
 197         if (print_banner == TRUE) {
 198                 if (!(whom = getlogin()) || !*whom)
 199                         whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
 200                 if (!whom) {
 201                         whom = "someone";
 202                         warn(_("cannot get passwd uid"));
 203                 }
 204                 where = ttyname(STDOUT_FILENO);
 205                 if (!where) {
 206                         where = "somewhere";
 207                         warn(_("cannot get tty name"));
 208                 }
 209                 gethostname(hostname, sizeof(hostname));
 210                 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                 /* snprintf is not always available, but the sprintf's here
 221                    will not overflow as long as %d takes at most 100 chars */
 222                 fprintf(fp, "\r%79s\r\n", " ");
 223                 sprintf(lbuf, _("Broadcast Message from %s@%s"),
 224                               whom, hostname);
 225                 fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
 226                 sprintf(lbuf, "        (%s) at %d:%02d ...",
 227                               where, lt->tm_hour, lt->tm_min);
 228                 fprintf(fp, "%-79.79s\r\n", lbuf);
 229         }
 230         fprintf(fp, "%79s\r\n", " ");
 231
 232         free(hostname);
 233
 234         if (fname) {
 235                 /*
 236                  * When we are not root, but suid or sgid, refuse to read files
 237                  * (e.g. device files) that the user may not have access to.
 238                  * After all, our invoker can easily do "wall < file"
 239                  * instead of "wall file".
 240                  */
 241                 uid_t uid = getuid();
 242                 if (uid && (uid != geteuid() || getgid() != getegid()))
 243                         errx(EXIT_FAILURE, _("will not read %s - use stdin."),
 244                              fname);
 245
 246                 if (!freopen(fname, "r", stdin))
 247                         err(EXIT_FAILURE, _("cannot open file %s"), fname);
 248         }
 249
 250         while (fgets(lbuf, line_max, stdin)) {
 251                 for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
 252                         if (cnt == 79 || ch == '\n') {
 253                                 for (; cnt < 79; ++cnt)
 254                                         putc(' ', fp);
 255                                 putc('\r', fp);
 256                                 putc('\n', fp);
 257                                 cnt = 0;
 258                         }
 259                         if (ch != '\n')
 260                                 carefulputc(ch, fp);
 261                 }
 262         }
 263         fprintf(fp, "%79s\r\n", " ");
 264
 265         free(lbuf);
 266         rewind(fp);
 267
 268         if (fstat(fileno(fp), &sbuf))
 269                 err(EXIT_FAILURE, _("fstat failed"));
 270
 271         *mbufsize = (size_t) sbuf.st_size;
 272         mbuf = xmalloc(*mbufsize);
 273
 274         if (fread(mbuf, 1, *mbufsize, fp) != *mbufsize)
 275                 err(EXIT_FAILURE, _("fread failed"));
 276
 277         if (close_stream(fp) != 0)
 278                 errx(EXIT_FAILURE, _("write error"));
 279         return mbuf;
 280 }