source: MondoRescue/branches/3.2/mindi-busybox/coreutils/tty.c@ 3232

/* vi: set sw=4 ts=4: */
/*
 * tty implementation for busybox
 *
 * Copyright (C) 2003  Manuel Novoa III  <mjn3@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

/* BB_AUDIT SUSv4 compliant */
/* http://www.opengroup.org/onlinepubs/9699919799/utilities/tty.html */

//usage:#define tty_trivial_usage
//usage:       ""
//usage:#define tty_full_usage "\n\n"
//usage:       "Print file name of stdin's terminal"
//usage:    IF_INCLUDE_SUSv2( "\n"
//usage:     "\n    -s  Print nothing, only return exit status"
//usage:    )
//usage:
//usage:#define tty_example_usage
//usage:       "$ tty\n"
//usage:       "/dev/tty2\n"

#include "libbb.h"

int tty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int tty_main(int argc UNUSED_PARAM, char **argv)
{
    const char *s;
    IF_INCLUDE_SUSv2(int silent;)  /* Note: No longer relevant in SUSv3. */
    int retval;

    xfunc_error_retval = 2;  /* SUSv3 requires > 1 for error. */

    IF_INCLUDE_SUSv2(silent = getopt32(argv, "s");)
    IF_INCLUDE_SUSv2(argv += optind;)
    IF_NOT_INCLUDE_SUSv2(argv += 1;)

    /* gnu tty outputs a warning that it is ignoring all args. */
    bb_warn_ignoring_args(argv[0]);

    retval = EXIT_SUCCESS;

    s = xmalloc_ttyname(STDIN_FILENO);
    if (s == NULL) {
    /* According to SUSv3, ttyname can fail with EBADF or ENOTTY.
     * We know the file descriptor is good, so failure means not a tty. */
        s = "not a tty";
        retval = EXIT_FAILURE;
    }
    IF_INCLUDE_SUSv2(if (!silent) puts(s);)
    IF_NOT_INCLUDE_SUSv2(puts(s);)

    fflush_stdout_and_exit(retval);
}