ln.c revision 26465 
1/*
2 * Copyright (c) 1987, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 *	$Id: ln.c,v 1.10 1997/03/28 15:24:22 imp Exp $
34 */
35
36#ifndef lint
37static char const copyright[] =
38"@(#) Copyright (c) 1987, 1993, 1994\n\
39	The Regents of the University of California.  All rights reserved.\n";
40#endif /* not lint */
41
42#ifndef lint
43static char const sccsid[] = "@(#)ln.c	8.2 (Berkeley) 3/31/94";
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 <stdio.h>
52#include <stdlib.h>
53#include <string.h>
54#include <unistd.h>
55
56int	fflag;				/* Unlink existing files. */
57int	sflag;				/* Symbolic, not hard, link. */
58					/* System link call. */
59int (*linkf) __P((const char *, const char *));
60
61int	linkit __P((char *, char *, int));
62void	usage __P((void));
63
64int
65main(argc, argv)
66	int argc;
67	char *argv[];
68{
69	extern int optind;
70	struct stat sb;
71	int ch, exitval;
72	char *sourcedir;
73
74	while ((ch = getopt(argc, argv, "fs")) != -1)
75		switch (ch) {
76		case 'f':
77			fflag = 1;
78			break;
79		case 's':
80			sflag = 1;
81			break;
82		case '?':
83		default:
84			usage();
85		}
86
87	argv += optind;
88	argc -= optind;
89
90	linkf = sflag ? symlink : link;
91
92	switch(argc) {
93	case 0:
94		usage();
95	case 1:				/* ln target */
96		exit(linkit(argv[0], ".", 1));
97	case 2:				/* ln target source */
98		exit(linkit(argv[0], argv[1], 0));
99	}
100					/* ln target1 target2 directory */
101	sourcedir = argv[argc - 1];
102	if (stat(sourcedir, &sb))
103		err(1, "%s", sourcedir);
104	if (!S_ISDIR(sb.st_mode))
105		usage();
106	for (exitval = 0; *argv != sourcedir; ++argv)
107		exitval |= linkit(*argv, sourcedir, 1);
108	exit(exitval);
109}
110
111int
112linkit(target, source, isdir)
113	char *target, *source;
114	int isdir;
115{
116	struct stat sb;
117	int exists;
118	char *p, path[MAXPATHLEN];
119
120	if (!sflag) {
121		/* If target doesn't exist, quit now. */
122		if (stat(target, &sb)) {
123			warn("%s", target);
124			return (1);
125		}
126		/* Only symbolic links to directories. */
127		if (S_ISDIR(sb.st_mode)) {
128			errno = EISDIR;
129			warn("%s", target);
130			return (1);
131		}
132	}
133
134	/* If the source is a directory, append the target's name. */
135	if (isdir || ((exists = !stat(source, &sb)) && S_ISDIR(sb.st_mode))) {
136		if ((p = strrchr(target, '/')) == NULL)
137			p = target;
138		else
139			++p;
140		(void)snprintf(path, sizeof(path), "%s/%s", source, p);
141		source = path;
142		exists = !lstat(source, &sb);
143	} else
144		exists = !lstat(source, &sb);
145
146	/*
147	 * If the file exists, and -f was specified, unlink it.
148	 * Attempt the link.
149	 */
150	if ((fflag && exists && unlink(source)) || (*linkf)(target, source)) {
151		warn("%s", source);
152		return (1);
153	}
154	return (0);
155}
156
157void
158usage()
159{
160	(void)fprintf(stderr, "%s\n%s\n",
161	    "usage: ln [-fs] file1 file2",
162	    "       ln [-fs] file ... directory");
163	exit(1);
164}
165