| 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Mini ln implementation for busybox
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| 4 | *
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| 5 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@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 SUSv3 compliant */
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| 11 | /* BB_AUDIT GNU options missing: -d, -F, -i, and -v. */
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| 12 | /* http://www.opengroup.org/onlinepubs/007904975/utilities/ln.html */
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| 13 |
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| 14 | //usage:#define ln_trivial_usage
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| 15 | //usage: "[OPTIONS] TARGET... LINK|DIR"
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| 16 | //usage:#define ln_full_usage "\n\n"
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| 17 | //usage: "Create a link LINK or DIR/TARGET to the specified TARGET(s)\n"
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| 18 | //usage: "\n -s Make symlinks instead of hardlinks"
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| 19 | //usage: "\n -f Remove existing destinations"
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| 20 | //usage: "\n -n Don't dereference symlinks - treat like normal file"
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| 21 | //usage: "\n -b Make a backup of the target (if exists) before link operation"
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| 22 | //usage: "\n -S suf Use suffix instead of ~ when making backup files"
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| 23 | //usage: "\n -T 2nd arg must be a DIR"
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| 24 | //usage: "\n -v Verbose"
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| 25 | //usage:
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| 26 | //usage:#define ln_example_usage
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| 27 | //usage: "$ ln -s BusyBox /tmp/ls\n"
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| 28 | //usage: "$ ls -l /tmp/ls\n"
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| 29 | //usage: "lrwxrwxrwx 1 root root 7 Apr 12 18:39 ls -> BusyBox*\n"
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| 30 |
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| 31 | #include "libbb.h"
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| 32 |
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| 33 | /* This is a NOEXEC applet. Be very careful! */
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| 34 |
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| 35 |
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| 36 | #define LN_SYMLINK (1 << 0)
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| 37 | #define LN_FORCE (1 << 1)
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| 38 | #define LN_NODEREFERENCE (1 << 2)
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| 39 | #define LN_BACKUP (1 << 3)
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| 40 | #define LN_SUFFIX (1 << 4)
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| 41 | #define LN_VERBOSE (1 << 5)
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| 42 | #define LN_LINKFILE (1 << 6)
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| 43 |
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| 44 | int ln_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 45 | int ln_main(int argc, char **argv)
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| 46 | {
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| 47 | int status = EXIT_SUCCESS;
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| 48 | int opts;
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| 49 | char *last;
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| 50 | char *src_name;
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| 51 | char *src;
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| 52 | char *suffix = (char*)"~";
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| 53 | struct stat statbuf;
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| 54 | int (*link_func)(const char *, const char *);
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| 55 |
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| 56 | opt_complementary = "-1"; /* min one arg */
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| 57 | opts = getopt32(argv, "sfnbS:vT", &suffix);
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| 58 |
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| 59 | last = argv[argc - 1];
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| 60 | argv += optind;
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| 61 | argc -= optind;
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| 62 |
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| 63 | if ((opts & LN_LINKFILE) && argc > 2) {
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| 64 | bb_error_msg_and_die("-T accepts 2 args max");
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| 65 | }
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| 66 |
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| 67 | if (!argv[1]) {
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| 68 | /* "ln PATH/TO/FILE" -> "ln PATH/TO/FILE FILE" */
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| 69 | *--argv = last;
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| 70 | /* xstrdup is needed: "ln -s PATH/TO/FILE/" is equivalent to
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| 71 | * "ln -s PATH/TO/FILE/ FILE", not "ln -s PATH/TO/FILE FILE"
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| 72 | */
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| 73 | last = bb_get_last_path_component_strip(xstrdup(last));
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| 74 | }
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| 75 |
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| 76 | do {
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| 77 | src_name = NULL;
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| 78 | src = last;
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| 79 |
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| 80 | if (is_directory(src,
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| 81 | (opts & LN_NODEREFERENCE) ^ LN_NODEREFERENCE
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| 82 | )
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| 83 | ) {
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| 84 | if (opts & LN_LINKFILE) {
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| 85 | bb_error_msg_and_die("'%s' is a directory", src);
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| 86 | }
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| 87 | src_name = xstrdup(*argv);
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| 88 | src = concat_path_file(src, bb_get_last_path_component_strip(src_name));
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| 89 | free(src_name);
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| 90 | src_name = src;
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| 91 | }
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| 92 | if (!(opts & LN_SYMLINK) && stat(*argv, &statbuf)) {
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| 93 | // coreutils: "ln dangling_symlink new_hardlink" works
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| 94 | if (lstat(*argv, &statbuf) || !S_ISLNK(statbuf.st_mode)) {
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| 95 | bb_simple_perror_msg(*argv);
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| 96 | status = EXIT_FAILURE;
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| 97 | free(src_name);
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| 98 | continue;
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| 99 | }
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| 100 | }
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| 101 |
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| 102 | if (opts & LN_BACKUP) {
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| 103 | char *backup;
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| 104 | backup = xasprintf("%s%s", src, suffix);
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| 105 | if (rename(src, backup) < 0 && errno != ENOENT) {
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| 106 | bb_simple_perror_msg(src);
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| 107 | status = EXIT_FAILURE;
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| 108 | free(backup);
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| 109 | continue;
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| 110 | }
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| 111 | free(backup);
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| 112 | /*
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| 113 | * When the source and dest are both hard links to the same
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| 114 | * inode, a rename may succeed even though nothing happened.
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| 115 | * Therefore, always unlink().
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| 116 | */
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| 117 | unlink(src);
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| 118 | } else if (opts & LN_FORCE) {
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| 119 | unlink(src);
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| 120 | }
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| 121 |
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| 122 | link_func = link;
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| 123 | if (opts & LN_SYMLINK) {
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| 124 | link_func = symlink;
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| 125 | }
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| 126 |
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| 127 | if (opts & LN_VERBOSE) {
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| 128 | printf("'%s' -> '%s'\n", src, *argv);
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| 129 | }
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| 130 |
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| 131 | if (link_func(*argv, src) != 0) {
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| 132 | bb_simple_perror_msg(src);
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| 133 | status = EXIT_FAILURE;
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| 134 | }
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| 135 |
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| 136 | free(src_name);
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| 137 |
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| 138 | } while ((++argv)[1]);
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| 139 |
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| 140 | return status;
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| 141 | }
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