/* $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); }