1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Mini readlink implementation for busybox
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4 | *
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5 | * Copyright (C) 2000,2001 Matt Kraai <kraai@alumni.carnegiemellon.edu>
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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 | //usage:#define readlink_trivial_usage
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11 | //usage: IF_FEATURE_READLINK_FOLLOW("[-fnv] ") "FILE"
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12 | //usage:#define readlink_full_usage "\n\n"
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13 | //usage: "Display the value of a symlink"
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14 | //usage: IF_FEATURE_READLINK_FOLLOW( "\n"
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15 | //usage: "\n -f Canonicalize by following all symlinks"
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16 | //usage: "\n -n Don't add newline"
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17 | //usage: "\n -v Verbose"
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18 | //usage: )
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19 |
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20 | #include "libbb.h"
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21 |
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22 | /*
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23 | * # readlink --version
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24 | * readlink (GNU coreutils) 6.10
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25 | * # readlink --help
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26 | * -f, --canonicalize
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27 | * canonicalize by following every symlink in
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28 | * every component of the given name recursively;
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29 | * all but the last component must exist
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30 | * -e, --canonicalize-existing
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31 | * canonicalize by following every symlink in
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32 | * every component of the given name recursively,
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33 | * all components must exist
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34 | * -m, --canonicalize-missing
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35 | * canonicalize by following every symlink in
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36 | * every component of the given name recursively,
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37 | * without requirements on components existence
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38 | * -n, --no-newline do not output the trailing newline
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39 | * -q, --quiet, -s, --silent suppress most error messages
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40 | * -v, --verbose report error messages
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41 | *
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42 | * bbox supports: -f (partially) -n -v (fully), -q -s (accepts but ignores)
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43 | * Note: we export the -f flag, but our -f behaves like coreutils' -e.
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44 | * Unfortunately, there isn't a C lib function we can leverage to get this
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45 | * behavior which means we'd have to implement the full stack ourselves :(.
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46 | */
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47 |
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48 | int readlink_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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49 | int readlink_main(int argc UNUSED_PARAM, char **argv)
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50 | {
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51 | char *buf;
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52 | char *fname;
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53 |
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54 | IF_FEATURE_READLINK_FOLLOW(
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55 | unsigned opt;
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56 | /* We need exactly one non-option argument. */
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57 | opt_complementary = "=1";
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58 | opt = getopt32(argv, "fnvsq");
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59 | fname = argv[optind];
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60 | )
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61 | IF_NOT_FEATURE_READLINK_FOLLOW(
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62 | const unsigned opt = 0;
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63 | if (argc != 2) bb_show_usage();
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64 | fname = argv[1];
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65 | )
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66 |
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67 | /* compat: coreutils readlink reports errors silently via exit code */
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68 | if (!(opt & 4)) /* not -v */
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69 | logmode = LOGMODE_NONE;
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70 |
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71 | if (opt & 1) { /* -f */
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72 | buf = xmalloc_realpath(fname);
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73 | } else {
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74 | buf = xmalloc_readlink_or_warn(fname);
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75 | }
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76 |
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77 | if (!buf)
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78 | return EXIT_FAILURE;
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79 | printf((opt & 2) ? "%s" : "%s\n", buf);
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80 |
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81 | if (ENABLE_FEATURE_CLEAN_UP)
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82 | free(buf);
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83 |
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84 | fflush_stdout_and_exit(EXIT_SUCCESS);
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85 | }
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