blob: 0bd323b2af648e7ae5355a2b7bbe37afcb98437b [file] [log] [blame]
Erik Andersene49d5ec2000-02-08 19:58:47 +00001/* vi: set sw=4 ts=4: */
Eric Andersenf6be9441999-10-13 21:12:06 +00002/*
3 * Mini ln implementation for busybox
4 *
Eric Andersenc7bda1c2004-03-15 08:29:22 +00005 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
Eric Andersenf6be9441999-10-13 21:12:06 +00006 *
Denys Vlasenko0ef64bd2010-08-16 20:14:46 +02007 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
Eric Andersenf6be9441999-10-13 21:12:06 +00008 */
Denys Vlasenkoaf3f4202016-11-23 14:46:56 +01009//config:config LN
Denys Vlasenko4eed2c62017-07-18 22:01:24 +020010//config: bool "ln (4.5 kb)"
Denys Vlasenkoaf3f4202016-11-23 14:46:56 +010011//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-$(CONFIG_LN) += ln.o
Eric Andersenf6be9441999-10-13 21:12:06 +000018
Manuel Novoa III cad53642003-03-19 09:13:01 +000019/* BB_AUDIT SUSv3 compliant */
Rob Landley3071e2f2005-04-29 22:13:04 +000020/* BB_AUDIT GNU options missing: -d, -F, -i, and -v. */
Manuel Novoa III cad53642003-03-19 09:13:01 +000021/* http://www.opengroup.org/onlinepubs/007904975/utilities/ln.html */
22
Pere Orga34425382011-03-31 14:43:25 +020023//usage:#define ln_trivial_usage
24//usage: "[OPTIONS] TARGET... LINK|DIR"
25//usage:#define ln_full_usage "\n\n"
26//usage: "Create a link LINK or DIR/TARGET to the specified TARGET(s)\n"
Pere Orga34425382011-03-31 14:43:25 +020027//usage: "\n -s Make symlinks instead of hardlinks"
28//usage: "\n -f Remove existing destinations"
29//usage: "\n -n Don't dereference symlinks - treat like normal file"
30//usage: "\n -b Make a backup of the target (if exists) before link operation"
31//usage: "\n -S suf Use suffix instead of ~ when making backup files"
Simon B44642d12012-05-06 13:18:35 +020032//usage: "\n -T 2nd arg must be a DIR"
33//usage: "\n -v Verbose"
Pere Orga34425382011-03-31 14:43:25 +020034//usage:
35//usage:#define ln_example_usage
36//usage: "$ 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
Denis Vlasenkob6adbf12007-05-26 19:00:18 +000040#include "libbb.h"
Eric Andersencbe31da2001-02-20 06:14:08 +000041
Denis Vlasenko99912ca2007-04-10 15:43:37 +000042/* This is a NOEXEC applet. Be very careful! */
43
44
Simon B44642d12012-05-06 13:18:35 +020045#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)
Eric Andersenf6be9441999-10-13 21:12:06 +000052
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +000053int ln_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Rob Landleydfba7412006-03-06 20:47:33 +000054int ln_main(int argc, char **argv)
Eric Andersencc8ed391999-10-05 16:24:54 +000055{
Eric Andersen13241df2000-10-04 16:02:53 +000056 int status = EXIT_SUCCESS;
Denys Vlasenkoe992bae2009-11-28 15:18:53 +010057 int opts;
Manuel Novoa III cad53642003-03-19 09:13:01 +000058 char *last;
59 char *src_name;
Glenn L McGrathcfc0ad42003-12-31 23:10:44 +000060 char *src;
Denis Vlasenkoa41fdf32007-01-29 22:51:00 +000061 char *suffix = (char*)"~";
Glenn L McGrathcfc0ad42003-12-31 23:10:44 +000062 struct stat statbuf;
Manuel Novoa III cad53642003-03-19 09:13:01 +000063 int (*link_func)(const char *, const char *);
64
Denys Vlasenkoe992bae2009-11-28 15:18:53 +010065 opt_complementary = "-1"; /* min one arg */
Simon B44642d12012-05-06 13:18:35 +020066 opts = getopt32(argv, "sfnbS:vT", &suffix);
Manuel Novoa III cad53642003-03-19 09:13:01 +000067
68 last = argv[argc - 1];
69 argv += optind;
Simon B44642d12012-05-06 13:18:35 +020070 argc -= optind;
71
72 if ((opts & LN_LINKFILE) && argc > 2) {
73 bb_error_msg_and_die("-T accepts 2 args max");
74 }
Manuel Novoa III cad53642003-03-19 09:13:01 +000075
Denys Vlasenkob0e8ced2011-03-21 12:36:35 +010076 if (!argv[1]) {
77 /* "ln PATH/TO/FILE" -> "ln PATH/TO/FILE FILE" */
Manuel Novoa III cad53642003-03-19 09:13:01 +000078 *--argv = last;
Denys Vlasenkob0e8ced2011-03-21 12:36:35 +010079 /* 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 */
Denis Vlasenko818322b2007-09-24 18:27:04 +000082 last = bb_get_last_path_component_strip(xstrdup(last));
Manuel Novoa III cad53642003-03-19 09:13:01 +000083 }
84
85 do {
Glenn L McGrathcfc0ad42003-12-31 23:10:44 +000086 src_name = NULL;
Manuel Novoa III cad53642003-03-19 09:13:01 +000087 src = last;
88
89 if (is_directory(src,
Denys Vlasenkof282c6b2011-12-18 03:27:46 +010090 (opts & LN_NODEREFERENCE) ^ LN_NODEREFERENCE
91 )
Denis Vlasenko6a2f7f42007-08-16 10:35:17 +000092 ) {
Simon B44642d12012-05-06 13:18:35 +020093 if (opts & LN_LINKFILE) {
94 bb_error_msg_and_die("'%s' is a directory", src);
95 }
Rob Landleyd921b2e2006-08-03 15:41:12 +000096 src_name = xstrdup(*argv);
Denis Vlasenko818322b2007-09-24 18:27:04 +000097 src = concat_path_file(src, bb_get_last_path_component_strip(src_name));
Manuel Novoa III cad53642003-03-19 09:13:01 +000098 free(src_name);
Glenn L McGrathcfc0ad42003-12-31 23:10:44 +000099 src_name = src;
100 }
Denys Vlasenkoe992bae2009-11-28 15:18:53 +0100101 if (!(opts & LN_SYMLINK) && stat(*argv, &statbuf)) {
Denis Vlasenkof24e1f42006-10-21 23:40:20 +0000102 // coreutils: "ln dangling_symlink new_hardlink" works
103 if (lstat(*argv, &statbuf) || !S_ISLNK(statbuf.st_mode)) {
Denis Vlasenko0c97c9d2007-10-01 11:58:38 +0000104 bb_simple_perror_msg(*argv);
Denis Vlasenkof24e1f42006-10-21 23:40:20 +0000105 status = EXIT_FAILURE;
106 free(src_name);
107 continue;
108 }
Eric Andersen815e9042000-06-06 16:15:23 +0000109 }
Manuel Novoa III cad53642003-03-19 09:13:01 +0000110
Denys Vlasenkoe992bae2009-11-28 15:18:53 +0100111 if (opts & LN_BACKUP) {
Denis Vlasenkof24e1f42006-10-21 23:40:20 +0000112 char *backup;
113 backup = xasprintf("%s%s", src, suffix);
114 if (rename(src, backup) < 0 && errno != ENOENT) {
Denis Vlasenko0c97c9d2007-10-01 11:58:38 +0000115 bb_simple_perror_msg(src);
Denis Vlasenkof24e1f42006-10-21 23:40:20 +0000116 status = EXIT_FAILURE;
Rob Landley3071e2f2005-04-29 22:13:04 +0000117 free(backup);
Denis Vlasenkof24e1f42006-10-21 23:40:20 +0000118 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);
Denys Vlasenkoe992bae2009-11-28 15:18:53 +0100127 } else if (opts & LN_FORCE) {
Manuel Novoa III cad53642003-03-19 09:13:01 +0000128 unlink(src);
129 }
130
131 link_func = link;
Denys Vlasenkoe992bae2009-11-28 15:18:53 +0100132 if (opts & LN_SYMLINK) {
Manuel Novoa III cad53642003-03-19 09:13:01 +0000133 link_func = symlink;
134 }
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000135
Simon B44642d12012-05-06 13:18:35 +0200136 if (opts & LN_VERBOSE) {
137 printf("'%s' -> '%s'\n", src, *argv);
138 }
139
Manuel Novoa III cad53642003-03-19 09:13:01 +0000140 if (link_func(*argv, src) != 0) {
Denis Vlasenko0c97c9d2007-10-01 11:58:38 +0000141 bb_simple_perror_msg(src);
Glenn L McGrathcfc0ad42003-12-31 23:10:44 +0000142 status = EXIT_FAILURE;
Manuel Novoa III cad53642003-03-19 09:13:01 +0000143 }
144
145 free(src_name);
Manuel Novoa III cad53642003-03-19 09:13:01 +0000146 } while ((++argv)[1]);
147
Eric Andersenfcffa2c2002-04-06 05:17:57 +0000148 return status;
Eric Andersencc8ed391999-10-05 16:24:54 +0000149}