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/* $OpenBSD: mesg.c,v 1.16 2019/06/28 13:35:02 deraadt Exp $ */
/* $NetBSD: mesg.c,v 1.4 1994/12/23 07:16:32 jtc Exp $ */
/*
* Copyright (c) 1987, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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. 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.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
int
main(int argc, char *argv[])
{
struct stat sb;
char *tty;
int ch;
while ((ch = getopt(argc, argv, "")) != -1)
switch (ch) {
case '?':
default:
goto usage;
}
argc -= optind;
argv += optind;
if ((tty = ttyname(STDERR_FILENO)) == NULL)
err(2, "ttyname");
if (unveil(tty, "rw") == -1)
err(2, "unveil");
if (pledge("stdio rpath fattr", NULL) == -1)
err(2, "pledge");
if (stat(tty, &sb) == -1)
err(2, "%s", tty);
sb.st_mode &= ACCESSPERMS;
if (*argv == NULL) {
if (sb.st_mode & S_IWGRP) {
(void)fprintf(stderr, "is y\n");
exit(0);
}
(void)fprintf(stderr, "is n\n");
exit(1);
}
switch (*argv[0]) {
case 'y':
if (chmod(tty, sb.st_mode | S_IWGRP) == -1)
err(2, "%s", tty);
exit(0);
case 'n':
if (chmod(tty, sb.st_mode & ~S_IWGRP) == -1)
err(2, "%s", tty);
exit(1);
}
usage: (void)fprintf(stderr, "usage: mesg [n | y]\n");
exit(2);
}
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