1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * tty implementation for busybox
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4 | *
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5 | * Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org>
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6 | *
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7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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8 | */
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9 |
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10 | /* BB_AUDIT SUSv4 compliant */
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11 | /* http://www.opengroup.org/onlinepubs/9699919799/utilities/tty.html */
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12 |
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13 | //usage:#define tty_trivial_usage
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14 | //usage: ""
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15 | //usage:#define tty_full_usage "\n\n"
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16 | //usage: "Print file name of stdin's terminal"
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17 | //usage: IF_INCLUDE_SUSv2( "\n"
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18 | //usage: "\n -s Print nothing, only return exit status"
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19 | //usage: )
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20 | //usage:
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21 | //usage:#define tty_example_usage
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22 | //usage: "$ tty\n"
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23 | //usage: "/dev/tty2\n"
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24 |
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25 | #include "libbb.h"
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26 |
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27 | int tty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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28 | int tty_main(int argc UNUSED_PARAM, char **argv)
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29 | {
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30 | const char *s;
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31 | IF_INCLUDE_SUSv2(int silent;) /* Note: No longer relevant in SUSv3. */
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32 | int retval;
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33 |
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34 | xfunc_error_retval = 2; /* SUSv3 requires > 1 for error. */
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35 |
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36 | IF_INCLUDE_SUSv2(silent = getopt32(argv, "s");)
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37 | IF_INCLUDE_SUSv2(argv += optind;)
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38 | IF_NOT_INCLUDE_SUSv2(argv += 1;)
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39 |
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40 | /* gnu tty outputs a warning that it is ignoring all args. */
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41 | bb_warn_ignoring_args(argv[0]);
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42 |
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43 | retval = EXIT_SUCCESS;
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44 |
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45 | s = xmalloc_ttyname(STDIN_FILENO);
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46 | if (s == NULL) {
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47 | /* According to SUSv3, ttyname can fail with EBADF or ENOTTY.
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48 | * We know the file descriptor is good, so failure means not a tty. */
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49 | s = "not a tty";
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50 | retval = EXIT_FAILURE;
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51 | }
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52 | IF_INCLUDE_SUSv2(if (!silent) puts(s);)
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53 | IF_NOT_INCLUDE_SUSv2(puts(s);)
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54 |
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55 | fflush_stdout_and_exit(retval);
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56 | }
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