busybox/coreutils/ln.c

/* vi: set sw=4 ts=4: */
/*
 * Mini ln implementation for busybox
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

/* BB_AUDIT SUSv3 compliant */
/* BB_AUDIT GNU options missing: -d, -F, -i, and -v. */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/ln.html */

#include "libbb.h"

/* This is a NOEXEC applet. Be very careful! */


#define LN_SYMLINK          1
#define LN_FORCE            2
#define LN_NODEREFERENCE    4
#define LN_BACKUP           8
#define LN_SUFFIX           16

int ln_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int ln_main(int argc, char **argv)
{
	int status = EXIT_SUCCESS;
	int flag;
	char *last;
	char *src_name;
	char *src;
	char *suffix = (char*)"~";
	struct stat statbuf;
	int (*link_func)(const char *, const char *);

	flag = getopt32(argv, "sfnbS:", &suffix);

	if (argc == optind) {
		bb_show_usage();
	}

	last = argv[argc - 1];
	argv += optind;

	if (argc == optind + 1) {
		*--argv = last;
		last = bb_get_last_path_component_strip(xstrdup(last));
	}

	do {
		src_name = NULL;
		src = last;

		if (is_directory(src,
		                (flag & LN_NODEREFERENCE) ^ LN_NODEREFERENCE,
		                NULL)
		) {
			src_name = xstrdup(*argv);
			src = concat_path_file(src, bb_get_last_path_component_strip(src_name));
			free(src_name);
			src_name = src;
		}
		if (!(flag & LN_SYMLINK) && stat(*argv, &statbuf)) {
			// coreutils: "ln dangling_symlink new_hardlink" works
			if (lstat(*argv, &statbuf) || !S_ISLNK(statbuf.st_mode)) {
				bb_simple_perror_msg(*argv);
				status = EXIT_FAILURE;
				free(src_name);
				continue;
			}
		}

		if (flag & LN_BACKUP) {
			char *backup;
			backup = xasprintf("%s%s", src, suffix);
			if (rename(src, backup) < 0 && errno != ENOENT) {
				bb_simple_perror_msg(src);
				status = EXIT_FAILURE;
				free(backup);
				continue;
			}
			free(backup);
			/*
			 * When the source and dest are both hard links to the same
			 * inode, a rename may succeed even though nothing happened.
			 * Therefore, always unlink().
			 */
			unlink(src);
		} else if (flag & LN_FORCE) {
			unlink(src);
		}

		link_func = link;
		if (flag & LN_SYMLINK) {
			link_func = symlink;
		}

		if (link_func(*argv, src) != 0) {
			bb_simple_perror_msg(src);
			status = EXIT_FAILURE;
		}

		free(src_name);

	} while ((++argv)[1]);

	return status;
}
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 tarball for details.
8	*/
9
10	/* BB_AUDIT SUSv3 compliant */
11	/* BB_AUDIT GNU options missing: -d, -F, -i, and -v. */
12	/* http://www.opengroup.org/onlinepubs/007904975/utilities/ln.html */
13
14	#include "libbb.h"
15
16	/* This is a NOEXEC applet. Be very careful! */
17
18
19	#define LN_SYMLINK 1
20	#define LN_FORCE 2
21	#define LN_NODEREFERENCE 4
22	#define LN_BACKUP 8
23	#define LN_SUFFIX 16
24
25	int ln_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
26	int ln_main(int argc, char **argv)
27	{
28	int status = EXIT_SUCCESS;
29	int flag;
30	char *last;
31	char *src_name;
32	char *src;
33	char suffix = (char)"~";
34	struct stat statbuf;
35	int (link_func)(const char , const char *);
36
37	flag = getopt32(argv, "sfnbS:", &suffix);
38
39	if (argc == optind) {
40	bb_show_usage();
41	}
42
43	last = argv[argc - 1];
44	argv += optind;
45
46	if (argc == optind + 1) {
47	*--argv = last;
48	last = bb_get_last_path_component_strip(xstrdup(last));
49	}
50
51	do {
52	src_name = NULL;
53	src = last;
54
55	if (is_directory(src,
56	(flag & LN_NODEREFERENCE) ^ LN_NODEREFERENCE,
57	NULL)
58	) {
59	src_name = xstrdup(*argv);
60	src = concat_path_file(src, bb_get_last_path_component_strip(src_name));
61	free(src_name);
62	src_name = src;
63	}
64	if (!(flag & LN_SYMLINK) && stat(*argv, &statbuf)) {
65	// coreutils: "ln dangling_symlink new_hardlink" works
66	if (lstat(*argv, &statbuf) \|\| !S_ISLNK(statbuf.st_mode)) {
67	bb_simple_perror_msg(*argv);
68	status = EXIT_FAILURE;
69	free(src_name);
70	continue;
71	}
72	}
73
74	if (flag & LN_BACKUP) {
75	char *backup;
76	backup = xasprintf("%s%s", src, suffix);
77	if (rename(src, backup) < 0 && errno != ENOENT) {
78	bb_simple_perror_msg(src);
79	status = EXIT_FAILURE;
80	free(backup);
81	continue;
82	}
83	free(backup);
84	/*
85	* When the source and dest are both hard links to the same
86	* inode, a rename may succeed even though nothing happened.
87	* Therefore, always unlink().
88	*/
89	unlink(src);
90	} else if (flag & LN_FORCE) {
91	unlink(src);
92	}
93
94	link_func = link;
95	if (flag & LN_SYMLINK) {
96	link_func = symlink;
97	}
98
99	if (link_func(*argv, src) != 0) {
100	bb_simple_perror_msg(src);
101	status = EXIT_FAILURE;
102	}
103
104	free(src_name);
105
106	} while ((++argv)[1]);
107
108	return status;
109	}