1/* $NetBSD: ln.c,v 1.35 2011/08/29 14:38:30 joerg Exp $ */
2
3/*
4 * Copyright (c) 1987, 1993, 1994
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33#ifndef lint
34__COPYRIGHT("@(#) Copyright (c) 1987, 1993, 1994\
35 The Regents of the University of California.  All rights reserved.");
36#endif /* not lint */
37
38#ifndef lint
39#if 0
40static char sccsid[] = "@(#)ln.c	8.2 (Berkeley) 3/31/94";
41#else
42__RCSID("$NetBSD: ln.c,v 1.35 2011/08/29 14:38:30 joerg Exp $");
43#endif
44#endif /* not lint */
45
46#include <sys/param.h>
47#include <sys/stat.h>
48
49#include <err.h>
50#include <errno.h>
51#include <locale.h>
52#include <stdio.h>
53#include <stdlib.h>
54#include <string.h>
55#include <unistd.h>
56
57static int	fflag;				/* Unlink existing files. */
58static int	hflag;				/* Check new name for symlink first. */
59static int	iflag;				/* Interactive mode. */
60static int	sflag;				/* Symbolic, not hard, link. */
61static int	vflag;                          /* Verbose output */
62
63					/* System link call. */
64static int (*linkf)(const char *, const char *);
65static char   linkch;
66
67static int	linkit(const char *, const char *, int);
68__dead static void	usage(void);
69
70int
71main(int argc, char *argv[])
72{
73	struct stat sb;
74	int ch, exitval;
75	char *sourcedir;
76
77	setprogname(argv[0]);
78	(void)setlocale(LC_ALL, "");
79
80	while ((ch = getopt(argc, argv, "fhinsv")) != -1)
81		switch (ch) {
82		case 'f':
83			fflag = 1;
84			iflag = 0;
85			break;
86		case 'h':
87		case 'n':
88			hflag = 1;
89			break;
90		case 'i':
91			iflag = 1;
92			fflag = 0;
93			break;
94		case 's':
95			sflag = 1;
96			break;
97		case 'v':
98			vflag = 1;
99			break;
100		case '?':
101		default:
102			usage();
103			/* NOTREACHED */
104		}
105
106	argv += optind;
107	argc -= optind;
108
109	if (sflag) {
110		linkf  = symlink;
111		linkch = '-';
112	} else {
113		linkf  = link;
114		linkch = '=';
115	}
116
117	switch(argc) {
118	case 0:
119		usage();
120		/* NOTREACHED */
121	case 1:				/* ln target */
122		exit(linkit(argv[0], ".", 1));
123		/* NOTREACHED */
124	case 2:				/* ln target source */
125		exit(linkit(argv[0], argv[1], 0));
126		/* NOTREACHED */
127	}
128
129					/* ln target1 target2 directory */
130	sourcedir = argv[argc - 1];
131	if (hflag && lstat(sourcedir, &sb) == 0 && S_ISLNK(sb.st_mode)) {
132		/* we were asked not to follow symlinks, but found one at
133		   the target--simulate "not a directory" error */
134		errno = ENOTDIR;
135		err(EXIT_FAILURE, "%s", sourcedir);
136		/* NOTREACHED */
137	}
138	if (stat(sourcedir, &sb)) {
139		err(EXIT_FAILURE, "%s", sourcedir);
140		/* NOTREACHED */
141	}
142	if (!S_ISDIR(sb.st_mode)) {
143		usage();
144		/* NOTREACHED */
145	}
146	for (exitval = 0; *argv != sourcedir; ++argv)
147		exitval |= linkit(*argv, sourcedir, 1);
148	exit(exitval);
149	/* NOTREACHED */
150}
151
152static int
153linkit(const char *target, const char *source, int isdir)
154{
155	struct stat sb;
156	const char *p;
157	char path[MAXPATHLEN];
158	int ch, exists, first;
159
160	if (!sflag) {
161		/* If target doesn't exist, quit now. */
162		if (stat(target, &sb)) {
163			warn("%s", target);
164			return (1);
165		}
166	}
167
168	/* If the source is a directory (and not a symlink if hflag),
169	   append the target's name. */
170	if (isdir ||
171	    (!lstat(source, &sb) && S_ISDIR(sb.st_mode)) ||
172	    (!hflag && !stat(source, &sb) && S_ISDIR(sb.st_mode))) {
173		if ((p = strrchr(target, '/')) == NULL)
174			p = target;
175		else
176			++p;
177		(void)snprintf(path, sizeof(path), "%s/%s", source, p);
178		source = path;
179	}
180
181	exists = !lstat(source, &sb);
182
183	/*
184	 * If the file exists, then unlink it forcibly if -f was specified
185	 * and interactively if -i was specified.
186	 */
187	if (fflag && exists) {
188		if (unlink(source)) {
189			warn("%s", source);
190			return (1);
191		}
192	} else if (iflag && exists) {
193		fflush(stdout);
194		(void)fprintf(stderr, "replace %s? ", source);
195
196		first = ch = getchar();
197		while (ch != '\n' && ch != EOF)
198			ch = getchar();
199		if (first != 'y' && first != 'Y') {
200			(void)fprintf(stderr, "not replaced\n");
201			return (1);
202		}
203
204		if (unlink(source)) {
205			warn("%s", source);
206			return (1);
207		}
208	}
209
210	/* Attempt the link. */
211	if ((*linkf)(target, source)) {
212		warn("%s", source);
213		return (1);
214	}
215	if (vflag)
216		(void)printf("%s %c> %s\n", source, linkch, target);
217
218	return (0);
219}
220
221static void
222usage(void)
223{
224
225	(void)fprintf(stderr,
226	    "usage:\t%s [-fhinsv] file1 file2\n\t%s [-fhinsv] file ... directory\n",
227	    getprogname(), getprogname());
228	exit(1);
229	/* NOTREACHED */
230}
231