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 TERM_WIDTH      79
  73 #define WRITE_TIME_OUT  300             /* in seconds */
  74
  75 /* Function prototypes */
  76 static char *makemsg(char *fname, char **mvec, int mvecsz,
  77                     size_t *mbufsize, int print_banner);
  78
  79 static void __attribute__((__noreturn__)) usage(FILE *out)
  80 {
  81         fputs(USAGE_HEADER, out);
  82         fprintf(out,
  83               _(" %s [options] [<file> | <message>]\n"), program_invocation_short_name);
  84         fputs(USAGE_OPTIONS, out);
  85         fputs(_(" -n, --nobanner          do not print banner, works only for root\n"), out);
  86         fputs(_(" -t, --timeout <timeout> write timeout in seconds\n"), out);
  87         fputs(USAGE_SEPARATOR, out);
  88         fputs(USAGE_HELP, out);
  89         fputs(USAGE_VERSION, out);
  90         fprintf(out, USAGE_MAN_TAIL("wall(1)"));
  91
  92         exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
  93 }
  94
  95 int main(int argc, char **argv)
  96 {
  97         int ch;
  98         struct iovec iov;
  99         struct utmp *utmpptr;
 100         char *p;
 101         char line[sizeof(utmpptr->ut_line) + 1];
 102         int print_banner = TRUE;
 103         char *mbuf, *fname = NULL;
 104         size_t mbufsize;
 105         unsigned timeout = WRITE_TIME_OUT;
 106         char **mvec = NULL;
 107         int mvecsz = 0;
 108
 109         static const struct option longopts[] = {
 110                 { "nobanner",   no_argument,            0, 'n' },
 111                 { "timeout",    required_argument,      0, 't' },
 112                 { "version",    no_argument,            0, 'V' },
 113                 { "help",       no_argument,            0, 'h' },
 114                 { NULL, 0, 0, 0 }
 115         };
 116
 117         setlocale(LC_ALL, "");
 118         bindtextdomain(PACKAGE, LOCALEDIR);
 119         textdomain(PACKAGE);
 120         atexit(close_stdout);
 121
 122         while ((ch = getopt_long(argc, argv, "nt:Vh", longopts, NULL)) != -1) {
 123                 switch (ch) {
 124                 case 'n':
 125                         if (geteuid() == 0)
 126                                 print_banner = FALSE;
 127                         else
 128                                 warnx(_("--nobanner is available only for root"));
 129                         break;
 130                 case 't':
 131                         timeout = strtou32_or_err(optarg, _("invalid timeout argument"));
 132                         if (timeout < 1)
 133                                 errx(EXIT_FAILURE, _("invalid timeout argument: %s"), optarg);
 134                         break;
 135                 case 'V':
 136                         printf(UTIL_LINUX_VERSION);
 137                         exit(EXIT_SUCCESS);
 138                 case 'h':
 139                         usage(stdout);
 140                 default:
 141                         usage(stderr);
 142                 }
 143         }
 144         argc -= optind;
 145         argv += optind;
 146
 147         if (argc == 1 && access(argv[0], F_OK) == 0)
 148                 fname = argv[0];
 149         else if (argc >= 1) {
 150                 mvec = argv;
 151                 mvecsz = argc;
 152         }
 153
 154         mbuf = makemsg(fname, mvec, mvecsz, &mbufsize, print_banner);
 155
 156         iov.iov_base = mbuf;
 157         iov.iov_len = mbufsize;
 158         while((utmpptr = getutent())) {
 159                 if (!utmpptr->ut_user[0])
 160                         continue;
 161 #ifdef USER_PROCESS
 162                 if (utmpptr->ut_type != USER_PROCESS)
 163                         continue;
 164 #endif
 165                 /* Joey Hess reports that use-sessreg in /etc/X11/wdm/
 166                    produces ut_line entries like :0, and a write
 167                    to /dev/:0 fails. */
 168                 if (utmpptr->ut_line[0] == ':')
 169                         continue;
 170
 171                 xstrncpy(line, utmpptr->ut_line, sizeof(utmpptr->ut_line));
 172                 if ((p = ttymsg(&iov, 1, line, timeout)) != NULL)
 173                         warnx("%s", p);
 174         }
 175         endutent();
 176         free(mbuf);
 177         exit(EXIT_SUCCESS);
 178 }
 179
 180 static char *makemsg(char *fname, char **mvec, int mvecsz,
 181                      size_t *mbufsize, int print_banner)
 182 {
 183         register int ch, cnt;
 184         struct stat sbuf;
 185         FILE *fp;
 186         char *p, *lbuf, *tmpname, *mbuf;
 187         long line_max;
 188
 189         line_max = sysconf(_SC_LINE_MAX);
 190         if (line_max <= 0)
 191                 line_max = 512;
 192
 193         lbuf = xmalloc(line_max);
 194
 195         if ((fp = xfmkstemp(&tmpname, NULL)) == NULL)
 196                 err(EXIT_FAILURE, _("can't open temporary file"));
 197         unlink(tmpname);
 198         free(tmpname);
 199
 200         if (print_banner == TRUE) {
 201                 char *hostname = xgethostname();
 202                 char *whom, *where, *date;
 203                 struct passwd *pw;
 204                 time_t now;
 205
 206                 if (!(whom = getlogin()) || !*whom)
 207                         whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
 208                 if (!whom) {
 209                         whom = "someone";
 210                         warn(_("cannot get passwd uid"));
 211                 }
 212                 where = ttyname(STDOUT_FILENO);
 213                 if (!where) {
 214                         where = "somewhere";
 215                         warn(_("cannot get tty name"));
 216                 } else if (strncmp(where, "/dev/", 5) == 0)
 217                         where += 5;
 218
 219                 time(&now);
 220                 date = xstrdup(ctime(&now));
 221                 date[strlen(date) - 1] = '\0';
 222
 223                 /*
 224                  * all this stuff is to blank out a square for the message;
 225                  * we wrap message lines at column 79, not 80, because some
 226                  * terminals wrap after 79, some do not, and we can't tell.
 227                  * Which means that we may leave a non-blank character
 228                  * in column 80, but that can't be helped.
 229                  */
 230                 /* snprintf is not always available, but the sprintf's here
 231                    will not overflow as long as %d takes at most 100 chars */
 232                 fprintf(fp, "\r%*s\r\n", TERM_WIDTH, " ");
 233                 sprintf(lbuf, _("Broadcast message from %s@%s (%s) (%s):"),
 234                               whom, hostname, where, date);
 235                 fprintf(fp, "%-*.*s\007\007\r\n", TERM_WIDTH, TERM_WIDTH, lbuf);
 236                 free(hostname);
 237                 free(date);
 238         }
 239         fprintf(fp, "%*s\r\n", TERM_WIDTH, " ");
 240
 241          if (mvec) {
 242                 /*
 243                  * Read message from argv[]
 244                  */
 245                 int i;
 246
 247                 for (i = 0; i < mvecsz; i++) {
 248                         fputs(mvec[i], fp);
 249                         if (i < mvecsz - 1)
 250                                 fputc(' ', fp);
 251                 }
 252                 fputc('\r', fp);
 253                 fputc('\n', fp);
 254
 255         } else {
 256                 /*
 257                  * read message from <file>
 258                  */
 259                 if (fname) {
 260                         /*
 261                          * When we are not root, but suid or sgid, refuse to read files
 262                          * (e.g. device files) that the user may not have access to.
 263                          * After all, our invoker can easily do "wall < file"
 264                          * instead of "wall file".
 265                          */
 266                         uid_t uid = getuid();
 267                         if (uid && (uid != geteuid() || getgid() != getegid()))
 268                                 errx(EXIT_FAILURE, _("will not read %s - use stdin."),
 269                                      fname);
 270
 271                         if (!freopen(fname, "r", stdin))
 272                                 err(EXIT_FAILURE, _("cannot open %s"), fname);
 273
 274                 }
 275
 276                 /*
 277                  * Read message from stdin.
 278                  */
 279                 while (fgets(lbuf, line_max, stdin)) {
 280                         for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
 281                                 if (cnt == TERM_WIDTH || ch == '\n') {
 282                                         for (; cnt < TERM_WIDTH; ++cnt)
 283                                                 putc(' ', fp);
 284                                         putc('\r', fp);
 285                                         putc('\n', fp);
 286                                         cnt = 0;
 287                                 }
 288                                 if (ch == '\t')
 289                                         cnt += (7 - (cnt % 8));
 290                                 if (ch != '\n')
 291                                         fputc_careful(ch, fp, '^');
 292                         }
 293                 }
 294         }
 295         fprintf(fp, "%*s\r\n", TERM_WIDTH, " ");
 296
 297         free(lbuf);
 298         rewind(fp);
 299
 300         if (fstat(fileno(fp), &sbuf))
 301                 err(EXIT_FAILURE, _("stat failed"));
 302
 303         *mbufsize = (size_t) sbuf.st_size;
 304         mbuf = xmalloc(*mbufsize);
 305
 306         if (fread(mbuf, 1, *mbufsize, fp) != *mbufsize)
 307                 err(EXIT_FAILURE, _("fread failed"));
 308
 309         if (close_stream(fp) != 0)
 310                 errx(EXIT_FAILURE, _("write error"));
 311         return mbuf;
 312 }