source: MondoRescue/branches/stable/mindi-busybox/init/mesg.c@ 821

/* vi: set sw=4 ts=4: */
/*
 * mesg implementation for busybox
 *
 * Copyright (c) 2002 Manuel Novoa III  <mjn3@codepoet.org>
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */

#include "busybox.h"
#include <unistd.h>
#include <stdlib.h>

#ifdef USE_TTY_GROUP
#define S_IWGRP_OR_S_IWOTH  S_IWGRP
#else
#define S_IWGRP_OR_S_IWOTH  (S_IWGRP | S_IWOTH)
#endif

int mesg_main(int argc, char *argv[])
{
    struct stat sb;
    char *tty;
    char c = 0;

    if ((--argc == 0)
        || ((argc == 1) && (((c = **++argv) == 'y') || (c == 'n')))) {
        if ((tty = ttyname(STDERR_FILENO)) == NULL) {
            tty = "ttyname";
        } else if (stat(tty, &sb) == 0) {
            if (argc == 0) {
                puts(((sb.st_mode & (S_IWGRP | S_IWOTH)) ==
                      0) ? "is n" : "is y");
                return EXIT_SUCCESS;
            }
            if (chmod
                (tty,
                 (c ==
                  'y') ? sb.st_mode | (S_IWGRP_OR_S_IWOTH) : sb.
                 st_mode & ~(S_IWGRP | S_IWOTH)) == 0) {
                return EXIT_SUCCESS;
            }
        }
        bb_perror_msg_and_die("%s", tty);
    }
    bb_show_usage();
}