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 Miśkiewicz <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 WRITE_TIME_OUT  300             /* in seconds */
  73
  74 /* Function prototypes */
  75 static char *makemsg(char *fname, char **mvec, int mvecsz,
  76                     size_t *mbufsize, int print_banner);
  77
  78 static void __attribute__((__noreturn__)) usage(FILE *out)
  79 {
  80         fputs(USAGE_HEADER, out);
  81         fprintf(out,
  82               _(" %s [options] [<file> | <message>]\n"), program_invocation_short_name);
  83         fputs(USAGE_OPTIONS, out);
  84         fputs(_(" -n, --nobanner          do not print banner, works only for root\n"), out);
  85         fputs(_(" -t, --timeout <timeout> write timeout in seconds\n"), out);
  86         fputs(USAGE_SEPARATOR, out);
  87         fputs(USAGE_HELP, out);
  88         fputs(USAGE_VERSION, out);
  89         fprintf(out, USAGE_MAN_TAIL("wall(1)"));
  90
  91         exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
  92 }
  93
  94 int main(int argc, char **argv)
  95 {
  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, *fname = NULL;
 103         size_t mbufsize;
 104         unsigned timeout = WRITE_TIME_OUT;
 105         char **mvec = NULL;
 106         int mvecsz = 0;
 107
 108         static const struct option longopts[] = {
 109                 { "nobanner",   no_argument,            0, 'n' },
 110                 { "timeout",    required_argument,      0, 't' },
 111                 { "version",    no_argument,            0, 'V' },
 112                 { "help",       no_argument,            0, 'h' },
 113                 { NULL, 0, 0, 0 }
 114         };
 115
 116         setlocale(LC_ALL, "");
 117         bindtextdomain(PACKAGE, LOCALEDIR);
 118         textdomain(PACKAGE);
 119         atexit(close_stdout);
 120
 121         while ((ch = getopt_long(argc, argv, "nt:Vh", longopts, NULL)) != -1) {
 122                 switch (ch) {
 123                 case 'n':
 124                         if (geteuid() == 0)
 125                                 print_banner = FALSE;
 126                         else
 127                                 warnx(_("--nobanner is available only for root"));
 128                         break;
 129                 case 't':
 130                         timeout = strtou32_or_err(optarg, _("invalid timeout argument"));
 131                         if (timeout < 1)
 132                                 errx(EXIT_FAILURE, _("invalid timeout argument: %s"), optarg);
 133                         break;
 134                 case 'V':
 135                         printf(UTIL_LINUX_VERSION);
 136                         exit(EXIT_SUCCESS);
 137                 case 'h':
 138                         usage(stdout);
 139                 default:
 140                         usage(stderr);
 141                 }
 142         }
 143         argc -= optind;
 144         argv += optind;
 145
 146         if (argc == 1 && access(argv[0], F_OK) == 0)
 147                 fname = argv[0];
 148         else if (argc >= 1) {
 149                 mvec = argv;
 150                 mvecsz = argc;
 151         }
 152
 153         mbuf = makemsg(fname, mvec, mvecsz, &mbufsize, print_banner);
 154
 155         iov.iov_base = mbuf;
 156         iov.iov_len = mbufsize;
 157         while((utmpptr = getutent())) {
 158                 if (!utmpptr->ut_user[0])
 159                         continue;
 160 #ifdef USER_PROCESS
 161                 if (utmpptr->ut_type != USER_PROCESS)
 162                         continue;
 163 #endif
 164                 /* Joey Hess reports that use-sessreg in /etc/X11/wdm/
 165                    produces ut_line entries like :0, and a write
 166                    to /dev/:0 fails. */
 167                 if (utmpptr->ut_line[0] == ':')
 168                         continue;
 169
 170                 xstrncpy(line, utmpptr->ut_line, sizeof(utmpptr->ut_line));
 171                 if ((p = ttymsg(&iov, 1, line, timeout)) != NULL)
 172                         warnx("%s", p);
 173         }
 174         endutent();
 175         free(mbuf);
 176         exit(EXIT_SUCCESS);
 177 }
 178
 179 static char *makemsg(char *fname, char **mvec, int mvecsz,
 180                      size_t *mbufsize, int print_banner)
 181 {
 182         register int ch, cnt;
 183         struct stat sbuf;
 184         FILE *fp;
 185         char *p, *lbuf, *tmpname, *mbuf;
 186         long line_max;
 187
 188         line_max = sysconf(_SC_LINE_MAX);
 189         lbuf = xmalloc(line_max);
 190
 191         if ((fp = xfmkstemp(&tmpname, NULL)) == NULL)
 192                 err(EXIT_FAILURE, _("can't open temporary file"));
 193         unlink(tmpname);
 194         free(tmpname);
 195
 196         if (print_banner == TRUE) {
 197                 char *hostname = xgethostname();
 198                 char *whom, *where, *date;
 199                 struct passwd *pw;
 200                 time_t now;
 201
 202                 if (!(whom = getlogin()) || !*whom)
 203                         whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
 204                 if (!whom) {
 205                         whom = "someone";
 206                         warn(_("cannot get passwd uid"));
 207                 }
 208                 where = ttyname(STDOUT_FILENO);
 209                 if (!where) {
 210                         where = "somewhere";
 211                         warn(_("cannot get tty name"));
 212                 } else if (strncmp(where, "/dev/", 5) == 0)
 213                         where += 5;
 214
 215                 time(&now);
 216                 date = xstrdup(ctime(&now));
 217                 date[strlen(date) - 1] = '\0';
 218
 219                 /*
 220                  * all this stuff is to blank out a square for the message;
 221                  * we wrap message lines at column 79, not 80, because some
 222                  * terminals wrap after 79, some do not, and we can't tell.
 223                  * Which means that we may leave a non-blank character
 224                  * in column 80, but that can't be helped.
 225                  */
 226                 /* snprintf is not always available, but the sprintf's here
 227                    will not overflow as long as %d takes at most 100 chars */
 228                 fprintf(fp, "\r%79s\r\n", " ");
 229                 sprintf(lbuf, _("Broadcast message from %s@%s (%s) (%s):"),
 230                               whom, hostname, where, date);
 231                 fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
 232                 free(hostname);
 233                 free(date);
 234         }
 235         fprintf(fp, "%79s\r\n", " ");
 236
 237          if (mvec) {
 238                 /*
 239                  * Read message from argv[]
 240                  */
 241                 int i;
 242
 243                 for (i = 0; i < mvecsz; i++) {
 244                         fputs(mvec[i], fp);
 245                         if (i < mvecsz - 1)
 246                                 fputc(' ', fp);
 247                 }
 248                 fputc('\r', fp);
 249                 fputc('\n', fp);
 250
 251         } else {
 252                 /*
 253                  * read message from <file>
 254                  */
 255                 if (fname) {
 256                         /*
 257                          * When we are not root, but suid or sgid, refuse to read files
 258                          * (e.g. device files) that the user may not have access to.
 259                          * After all, our invoker can easily do "wall < file"
 260                          * instead of "wall file".
 261                          */
 262                         uid_t uid = getuid();
 263                         if (uid && (uid != geteuid() || getgid() != getegid()))
 264                                 errx(EXIT_FAILURE, _("will not read %s - use stdin."),
 265                                      fname);
 266
 267                         if (!freopen(fname, "r", stdin))
 268                                 err(EXIT_FAILURE, _("cannot open %s"), fname);
 269
 270                 }
 271
 272                 /*
 273                  * Read message from stdin.
 274                  */
 275                 while (fgets(lbuf, line_max, stdin)) {
 276                         for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
 277                                 if (cnt == 79 || ch == '\n') {
 278                                         for (; cnt < 79; ++cnt)
 279                                                 putc(' ', fp);
 280                                         putc('\r', fp);
 281                                         putc('\n', fp);
 282                                         cnt = 0;
 283                                 }
 284                                 if (ch == '\t')
 285                                         cnt += (7 - (cnt % 8));
 286                                 if (ch != '\n')
 287                                         carefulputc(ch, fp, '^');
 288                         }
 289                 }
 290         }
 291         fprintf(fp, "%79s\r\n", " ");
 292
 293         free(lbuf);
 294         rewind(fp);
 295
 296         if (fstat(fileno(fp), &sbuf))
 297                 err(EXIT_FAILURE, _("stat failed"));
 298
 299         *mbufsize = (size_t) sbuf.st_size;
 300         mbuf = xmalloc(*mbufsize);
 301
 302         if (fread(mbuf, 1, *mbufsize, fp) != *mbufsize)
 303                 err(EXIT_FAILURE, _("fread failed"));
 304
 305         if (close_stream(fp) != 0)
 306                 errx(EXIT_FAILURE, _("write error"));
 307         return mbuf;
 308 }