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wall.c

/*
 * Copyright (c) 1988, 1990, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by the University of
 *    California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * Modified Sun Mar 12 10:34:34 1995, faith@cs.unc.edu, for Linux
 */

/*
 * This program is not related to David Wall, whose Stanford Ph.D. thesis
 * is entitled "Mechanisms for Broadcast and Selective Broadcast".
 *
 * 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@pld.ORG.PL>
 * - added Native Language Support
 *
 */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/uio.h>

#include <paths.h>
#include <ctype.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <utmp.h>

#include "nls.h"
#include "xstrncpy.h"
#include "ttymsg.h"
#include "pathnames.h"
#include "carefulputc.h"

void  makemsg __P((char *));

#define     IGNOREUSER  "sleeper"

int nobanner;
int mbufsize;
char *mbuf;

char *progname = "wall";

int
main(int argc, char **argv) {
      extern int optind;
      int ch;
      struct iovec iov;
      struct utmp *utmpptr;
      char *p;
      char line[sizeof(utmpptr->ut_line) + 1];

      setlocale(LC_ALL, "");
        bindtextdomain(PACKAGE, LOCALEDIR);
        textdomain(PACKAGE);

      progname = argv[0];
      p = rindex(progname, '/');
      if (p)
           progname = p+1;

      while ((ch = getopt(argc, argv, "n")) != -1)
            switch (ch) {
            case 'n':
                  /* undoc option for shutdown: suppress banner */
                  if (geteuid() == 0)
                        nobanner = 1;
                  break;
            case '?':
            default:
usage:
                  (void)fprintf(stderr, _("usage: %s [file]\n"), progname);
                  exit(1);
            }
      argc -= optind;
      argv += optind;
      if (argc > 1)
            goto usage;

      makemsg(*argv);

      setutent();

      iov.iov_base = mbuf;
      iov.iov_len = mbufsize;
      while((utmpptr = getutent())) {
            if (!utmpptr->ut_name[0] ||
                !strncmp(utmpptr->ut_name, IGNOREUSER,
                       sizeof(utmpptr->ut_name)))
                  continue;
#ifdef USER_PROCESS
            if (utmpptr->ut_type != USER_PROCESS)
                  continue;
#endif

            /* Joey Hess reports that use-sessreg in /etc/X11/wdm/
               produces ut_line entries like :0, and a write
               to /dev/:0 fails. */
            if (utmpptr->ut_line[0] == ':')
                  continue;

            xstrncpy(line, utmpptr->ut_line, sizeof(utmpptr->ut_line));
            if ((p = ttymsg(&iov, 1, line, 60*5)) != NULL)
                  (void)fprintf(stderr, "%s: %s\n", progname, p);
      }
      endutent();
      exit(0);
}

void
makemsg(fname)
      char *fname;
{
      register int ch, cnt;
      struct tm *lt;
      struct passwd *pw;
      struct stat sbuf;
      time_t now;
      FILE *fp;
      int fd;
      char *p, *whom, *where, hostname[MAXHOSTNAMELEN],
            lbuf[MAXHOSTNAMELEN + 320],
            tmpname[sizeof(_PATH_TMP) + 20];

      (void)sprintf(tmpname, "%s/wall.XXXXXX", _PATH_TMP);
      if (!(fd = mkstemp(tmpname)) || !(fp = fdopen(fd, "r+"))) {
            (void)fprintf(stderr, _("%s: can't open temporary file.\n"), progname);
            exit(1);
      }
      (void)unlink(tmpname);

      if (!nobanner) {
            if (!(whom = getlogin()) || !*whom)
                  whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
            if (!whom || strlen(whom) > 100)
                  whom = "someone";
            where = ttyname(2);
            if (!where || strlen(where) > 100)
                  where = "somewhere";
            (void)gethostname(hostname, sizeof(hostname));
            (void)time(&now);
            lt = localtime(&now);

            /*
             * all this stuff is to blank out a square for the message;
             * we wrap message lines at column 79, not 80, because some
             * terminals wrap after 79, some do not, and we can't tell.
             * Which means that we may leave a non-blank character
             * in column 80, but that can't be helped.
             */
            /* snprintf is not always available, but the sprintf's here
               will not overflow as long as %d takes at most 100 chars */
            (void)fprintf(fp, "\r%79s\r\n", " ");
            (void)sprintf(lbuf, _("Broadcast Message from %s@%s"),
                        whom, hostname);
            (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf);
            (void)sprintf(lbuf, "        (%s) at %d:%02d ...",
                        where, lt->tm_hour, lt->tm_min);
            (void)fprintf(fp, "%-79.79s\r\n", lbuf);
      }
      (void)fprintf(fp, "%79s\r\n", " ");

      if (fname) {
            /*
             * When we are not root, but suid or sgid, refuse to read files
             * (e.g. device files) that the user may not have access to.
             * After all, our invoker can easily do "wall < file"
             * instead of "wall file".
             */
            int uid = getuid();
            if (uid && (uid != geteuid() || getgid() != getegid())) {
                  fprintf(stderr, _("%s: will not read %s - use stdin.\n"),
                        progname, fname);
                  exit(1);
            }
            if (!freopen(fname, "r", stdin)) {
                  fprintf(stderr, _("%s: can't read %s.\n"),
                        progname, fname);
                  exit(1);
            }
      }

      while (fgets(lbuf, sizeof(lbuf), stdin)) {
            for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
                  if (cnt == 79 || ch == '\n') {
                        for (; cnt < 79; ++cnt)
                              putc(' ', fp);
                        putc('\r', fp);
                        putc('\n', fp);
                        cnt = 0;
                  }
                  carefulputc(ch, fp);
            }
      }
      fprintf(fp, "%79s\r\n", " ");
      rewind(fp);

      if (fstat(fd, &sbuf)) {
            fprintf(stderr, _("%s: can't stat temporary file.\n"),
                  progname);
            exit(1);
      }
      mbufsize = sbuf.st_size;
      if (!(mbuf = malloc((u_int)mbufsize))) {
            (void)fprintf(stderr, _("%s: Out of memory!\n"), progname);
            exit(1);
      }
      if (fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize) {
            (void)fprintf(stderr, _("%s: can't read temporary file.\n"), progname);
            exit(1);
      }
      (void)close(fd);
}

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