blob: 0e2abace49ce9430432d6e60c52362ed716d3536
| 1 | /* vi: set sw=4 ts=4: */ |
| 2 | /* |
| 3 | * Mini ln implementation for busybox |
| 4 | * |
| 5 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> |
| 6 | * |
| 7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| 8 | */ |
| 9 | //config:config LN |
| 10 | //config: bool "ln" |
| 11 | //config: default y |
| 12 | //config: help |
| 13 | //config: ln is used to create hard or soft links between files. |
| 14 | |
| 15 | //applet:IF_LN(APPLET_NOEXEC(ln, ln, BB_DIR_BIN, BB_SUID_DROP, ln)) |
| 16 | |
| 17 | //kbuild:lib-$(CONFIG_LN) += ln.o |
| 18 | |
| 19 | /* BB_AUDIT SUSv3 compliant */ |
| 20 | /* BB_AUDIT GNU options missing: -d, -F, -i, and -v. */ |
| 21 | /* http://www.opengroup.org/onlinepubs/007904975/utilities/ln.html */ |
| 22 | |
| 23 | //usage:#define ln_trivial_usage |
| 24 | //usage: "[OPTIONS] TARGET... LINK|DIR" |
| 25 | //usage:#define ln_full_usage "\n\n" |
| 26 | //usage: "Create a link LINK or DIR/TARGET to the specified TARGET(s)\n" |
| 27 | //usage: "\n -s Make symlinks instead of hardlinks" |
| 28 | //usage: "\n -f Remove existing destinations" |
| 29 | //usage: "\n -n Don't dereference symlinks - treat like normal file" |
| 30 | //usage: "\n -b Make a backup of the target (if exists) before link operation" |
| 31 | //usage: "\n -S suf Use suffix instead of ~ when making backup files" |
| 32 | //usage: "\n -T 2nd arg must be a DIR" |
| 33 | //usage: "\n -v Verbose" |
| 34 | //usage: |
| 35 | //usage:#define ln_example_usage |
| 36 | //usage: "$ ln -s BusyBox /tmp/ls\n" |
| 37 | //usage: "$ ls -l /tmp/ls\n" |
| 38 | //usage: "lrwxrwxrwx 1 root root 7 Apr 12 18:39 ls -> BusyBox*\n" |
| 39 | |
| 40 | #include "libbb.h" |
| 41 | |
| 42 | /* This is a NOEXEC applet. Be very careful! */ |
| 43 | |
| 44 | |
| 45 | #define LN_SYMLINK (1 << 0) |
| 46 | #define LN_FORCE (1 << 1) |
| 47 | #define LN_NODEREFERENCE (1 << 2) |
| 48 | #define LN_BACKUP (1 << 3) |
| 49 | #define LN_SUFFIX (1 << 4) |
| 50 | #define LN_VERBOSE (1 << 5) |
| 51 | #define LN_LINKFILE (1 << 6) |
| 52 | |
| 53 | int ln_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| 54 | int ln_main(int argc, char **argv) |
| 55 | { |
| 56 | int status = EXIT_SUCCESS; |
| 57 | int opts; |
| 58 | char *last; |
| 59 | char *src_name; |
| 60 | char *src; |
| 61 | char *suffix = (char*)"~"; |
| 62 | struct stat statbuf; |
| 63 | int (*link_func)(const char *, const char *); |
| 64 | |
| 65 | opt_complementary = "-1"; /* min one arg */ |
| 66 | opts = getopt32(argv, "sfnbS:vT", &suffix); |
| 67 | |
| 68 | last = argv[argc - 1]; |
| 69 | argv += optind; |
| 70 | argc -= optind; |
| 71 | |
| 72 | if ((opts & LN_LINKFILE) && argc > 2) { |
| 73 | bb_error_msg_and_die("-T accepts 2 args max"); |
| 74 | } |
| 75 | |
| 76 | if (!argv[1]) { |
| 77 | /* "ln PATH/TO/FILE" -> "ln PATH/TO/FILE FILE" */ |
| 78 | *--argv = last; |
| 79 | /* xstrdup is needed: "ln -s PATH/TO/FILE/" is equivalent to |
| 80 | * "ln -s PATH/TO/FILE/ FILE", not "ln -s PATH/TO/FILE FILE" |
| 81 | */ |
| 82 | last = bb_get_last_path_component_strip(xstrdup(last)); |
| 83 | } |
| 84 | |
| 85 | do { |
| 86 | src_name = NULL; |
| 87 | src = last; |
| 88 | |
| 89 | if (is_directory(src, |
| 90 | (opts & LN_NODEREFERENCE) ^ LN_NODEREFERENCE |
| 91 | ) |
| 92 | ) { |
| 93 | if (opts & LN_LINKFILE) { |
| 94 | bb_error_msg_and_die("'%s' is a directory", src); |
| 95 | } |
| 96 | src_name = xstrdup(*argv); |
| 97 | src = concat_path_file(src, bb_get_last_path_component_strip(src_name)); |
| 98 | free(src_name); |
| 99 | src_name = src; |
| 100 | } |
| 101 | if (!(opts & LN_SYMLINK) && stat(*argv, &statbuf)) { |
| 102 | // coreutils: "ln dangling_symlink new_hardlink" works |
| 103 | if (lstat(*argv, &statbuf) || !S_ISLNK(statbuf.st_mode)) { |
| 104 | bb_simple_perror_msg(*argv); |
| 105 | status = EXIT_FAILURE; |
| 106 | free(src_name); |
| 107 | continue; |
| 108 | } |
| 109 | } |
| 110 | |
| 111 | if (opts & LN_BACKUP) { |
| 112 | char *backup; |
| 113 | backup = xasprintf("%s%s", src, suffix); |
| 114 | if (rename(src, backup) < 0 && errno != ENOENT) { |
| 115 | bb_simple_perror_msg(src); |
| 116 | status = EXIT_FAILURE; |
| 117 | free(backup); |
| 118 | continue; |
| 119 | } |
| 120 | free(backup); |
| 121 | /* |
| 122 | * When the source and dest are both hard links to the same |
| 123 | * inode, a rename may succeed even though nothing happened. |
| 124 | * Therefore, always unlink(). |
| 125 | */ |
| 126 | unlink(src); |
| 127 | } else if (opts & LN_FORCE) { |
| 128 | unlink(src); |
| 129 | } |
| 130 | |
| 131 | link_func = link; |
| 132 | if (opts & LN_SYMLINK) { |
| 133 | link_func = symlink; |
| 134 | } |
| 135 | |
| 136 | if (opts & LN_VERBOSE) { |
| 137 | printf("'%s' -> '%s'\n", src, *argv); |
| 138 | } |
| 139 | |
| 140 | if (link_func(*argv, src) != 0) { |
| 141 | bb_simple_perror_msg(src); |
| 142 | status = EXIT_FAILURE; |
| 143 | } |
| 144 | |
| 145 | free(src_name); |
| 146 | } while ((++argv)[1]); |
| 147 | |
| 148 | return status; |
| 149 | } |
| 150 |