mirror of
https://github.com/topjohnwu/ndk-busybox.git
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f24e1f40e0
Add doc on POSIX's rules on -i and -f (insane!). ln: make "ln dangling_symlink new_link" work.
105 lines
2.3 KiB
C
105 lines
2.3 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 tarball for details.
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*/
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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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#include "busybox.h"
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#define LN_SYMLINK 1
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#define LN_FORCE 2
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#define LN_NODEREFERENCE 4
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#define LN_BACKUP 8
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#define LN_SUFFIX 16
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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 flag;
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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 = "~";
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struct stat statbuf;
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int (*link_func)(const char *, const char *);
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flag = getopt32(argc, argv, "sfnbS:", &suffix);
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if (argc == optind) {
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bb_show_usage();
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}
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last = argv[argc - 1];
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argv += optind;
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if (argc == optind + 1) {
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*--argv = last;
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last = bb_get_last_path_component(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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(flag & LN_NODEREFERENCE) ^ LN_NODEREFERENCE,
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NULL)) {
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src_name = xstrdup(*argv);
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src = concat_path_file(src, bb_get_last_path_component(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 (!(flag & 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_perror_msg("%s", *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 (flag & 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_perror_msg("%s", 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 (flag & LN_FORCE) {
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unlink(src);
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}
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link_func = link;
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if (flag & LN_SYMLINK) {
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link_func = symlink;
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}
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if (link_func(*argv, src) != 0) {
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bb_perror_msg("%s", 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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