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 opts;
	char *last;
	char *src_name;
	char *src;
	char *suffix = (char*)"~";
	struct stat statbuf;
	int (*link_func)(const char *, const char *);

	opt_complementary = "-1"; /* min one arg */
	opts = getopt32(argv, "sfnbS:", &suffix);

	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,
		                (opts & 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 (!(opts & 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 (opts & 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 (opts & LN_FORCE) {
			unlink(src);
		}

		link_func = link;
		if (opts & 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	niro	532	/* 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	niro	816	#include "libbb.h"
15	niro	532
16	niro	816	/* This is a NOEXEC applet. Be very careful! */
17
18
19	niro	532	#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	niro	816	int ln_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
26	niro	532	int ln_main(int argc, char **argv)
27			{
28			int status = EXIT_SUCCESS;
29	niro	984	int opts;
30	niro	532	char *last;
31			char *src_name;
32			char *src;
33	niro	816	char suffix = (char)"~";
34	niro	532	struct stat statbuf;
35			int (link_func)(const char , const char *);
36
37	niro	984	opt_complementary = "-1"; /* min one arg */
38			opts = getopt32(argv, "sfnbS:", &suffix);
39	niro	532
40			last = argv[argc - 1];
41			argv += optind;
42
43			if (argc == optind + 1) {
44			*--argv = last;
45	niro	816	last = bb_get_last_path_component_strip(xstrdup(last));
46	niro	532	}
47
48			do {
49			src_name = NULL;
50			src = last;
51
52			if (is_directory(src,
53	niro	984	(opts & LN_NODEREFERENCE) ^ LN_NODEREFERENCE,
54	niro	816	NULL)
55			) {
56	niro	532	src_name = xstrdup(*argv);
57	niro	816	src = concat_path_file(src, bb_get_last_path_component_strip(src_name));
58	niro	532	free(src_name);
59			src_name = src;
60			}
61	niro	984	if (!(opts & LN_SYMLINK) && stat(*argv, &statbuf)) {
62	niro	532	// coreutils: "ln dangling_symlink new_hardlink" works
63			if (lstat(*argv, &statbuf) \|\| !S_ISLNK(statbuf.st_mode)) {
64	niro	816	bb_simple_perror_msg(*argv);
65	niro	532	status = EXIT_FAILURE;
66			free(src_name);
67			continue;
68			}
69			}
70
71	niro	984	if (opts & LN_BACKUP) {
72	niro	532	char *backup;
73			backup = xasprintf("%s%s", src, suffix);
74			if (rename(src, backup) < 0 && errno != ENOENT) {
75	niro	816	bb_simple_perror_msg(src);
76	niro	532	status = EXIT_FAILURE;
77			free(backup);
78			continue;
79			}
80			free(backup);
81			/*
82			* When the source and dest are both hard links to the same
83			* inode, a rename may succeed even though nothing happened.
84			* Therefore, always unlink().
85			*/
86			unlink(src);
87	niro	984	} else if (opts & LN_FORCE) {
88	niro	532	unlink(src);
89			}
90
91			link_func = link;
92	niro	984	if (opts & LN_SYMLINK) {
93	niro	532	link_func = symlink;
94			}
95
96			if (link_func(*argv, src) != 0) {
97	niro	816	bb_simple_perror_msg(src);
98	niro	532	status = EXIT_FAILURE;
99			}
100
101			free(src_name);
102
103			} while ((++argv)[1]);
104
105			return status;
106			}