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150 lines
3.9 KiB
C
150 lines
3.9 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini ln implementation for busybox
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*
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* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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//config:config LN
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//config: bool "ln"
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//config: default y
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//config: help
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//config: ln is used to create hard or soft links between files.
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//applet:IF_LN(APPLET_NOEXEC(ln, ln, BB_DIR_BIN, BB_SUID_DROP, ln))
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//kbuild:lib-$(CONFIG_LN) += ln.o
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/* BB_AUDIT SUSv3 compliant */
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/* BB_AUDIT GNU options missing: -d, -F, -i, and -v. */
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/* http://www.opengroup.org/onlinepubs/007904975/utilities/ln.html */
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//usage:#define ln_trivial_usage
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//usage: "[OPTIONS] TARGET... LINK|DIR"
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//usage:#define ln_full_usage "\n\n"
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//usage: "Create a link LINK or DIR/TARGET to the specified TARGET(s)\n"
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//usage: "\n -s Make symlinks instead of hardlinks"
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//usage: "\n -f Remove existing destinations"
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//usage: "\n -n Don't dereference symlinks - treat like normal file"
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//usage: "\n -b Make a backup of the target (if exists) before link operation"
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//usage: "\n -S suf Use suffix instead of ~ when making backup files"
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//usage: "\n -T 2nd arg must be a DIR"
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//usage: "\n -v Verbose"
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//usage:
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//usage:#define ln_example_usage
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//usage: "$ ln -s BusyBox /tmp/ls\n"
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//usage: "$ ls -l /tmp/ls\n"
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//usage: "lrwxrwxrwx 1 root root 7 Apr 12 18:39 ls -> BusyBox*\n"
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#include "libbb.h"
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/* This is a NOEXEC applet. Be very careful! */
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#define LN_SYMLINK (1 << 0)
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#define LN_FORCE (1 << 1)
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#define LN_NODEREFERENCE (1 << 2)
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#define LN_BACKUP (1 << 3)
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#define LN_SUFFIX (1 << 4)
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#define LN_VERBOSE (1 << 5)
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#define LN_LINKFILE (1 << 6)
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int ln_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int ln_main(int argc, char **argv)
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{
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int status = EXIT_SUCCESS;
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int opts;
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char *last;
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char *src_name;
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char *src;
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char *suffix = (char*)"~";
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struct stat statbuf;
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int (*link_func)(const char *, const char *);
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opt_complementary = "-1"; /* min one arg */
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opts = getopt32(argv, "sfnbS:vT", &suffix);
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last = argv[argc - 1];
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argv += optind;
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argc -= optind;
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if ((opts & LN_LINKFILE) && argc > 2) {
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bb_error_msg_and_die("-T accepts 2 args max");
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}
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if (!argv[1]) {
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/* "ln PATH/TO/FILE" -> "ln PATH/TO/FILE FILE" */
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*--argv = last;
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/* xstrdup is needed: "ln -s PATH/TO/FILE/" is equivalent to
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* "ln -s PATH/TO/FILE/ FILE", not "ln -s PATH/TO/FILE FILE"
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*/
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last = bb_get_last_path_component_strip(xstrdup(last));
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}
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do {
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src_name = NULL;
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src = last;
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if (is_directory(src,
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(opts & LN_NODEREFERENCE) ^ LN_NODEREFERENCE
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)
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) {
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if (opts & LN_LINKFILE) {
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bb_error_msg_and_die("'%s' is a directory", src);
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}
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src_name = xstrdup(*argv);
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src = concat_path_file(src, bb_get_last_path_component_strip(src_name));
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free(src_name);
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src_name = src;
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}
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if (!(opts & LN_SYMLINK) && stat(*argv, &statbuf)) {
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// coreutils: "ln dangling_symlink new_hardlink" works
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if (lstat(*argv, &statbuf) || !S_ISLNK(statbuf.st_mode)) {
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bb_simple_perror_msg(*argv);
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status = EXIT_FAILURE;
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free(src_name);
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continue;
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}
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}
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if (opts & LN_BACKUP) {
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char *backup;
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backup = xasprintf("%s%s", src, suffix);
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if (rename(src, backup) < 0 && errno != ENOENT) {
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bb_simple_perror_msg(src);
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status = EXIT_FAILURE;
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free(backup);
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continue;
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}
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free(backup);
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/*
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* When the source and dest are both hard links to the same
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* inode, a rename may succeed even though nothing happened.
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* Therefore, always unlink().
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*/
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unlink(src);
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} else if (opts & LN_FORCE) {
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unlink(src);
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}
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link_func = link;
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if (opts & LN_SYMLINK) {
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link_func = symlink;
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}
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if (opts & LN_VERBOSE) {
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printf("'%s' -> '%s'\n", src, *argv);
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}
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if (link_func(*argv, src) != 0) {
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bb_simple_perror_msg(src);
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status = EXIT_FAILURE;
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}
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free(src_name);
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} while ((++argv)[1]);
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return status;
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}
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