ln.c revision 51148 
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
34#ifndef lint
35static char const copyright[] =
36"@(#) Copyright (c) 1987, 1993, 1994\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41#if 0
42static char sccsid[] = "@(#)ln.c	8.2 (Berkeley) 3/31/94";
43#endif
44static const char rcsid[] =
45  "$FreeBSD: head/bin/ln/ln.c 51148 1999-09-11 10:06:56Z obrien $";
46#endif /* not lint */
47
48#include <sys/param.h>
49#include <sys/stat.h>
50
51#include <err.h>
52#include <errno.h>
53#include <stdio.h>
54#include <stdlib.h>
55#include <string.h>
56#include <unistd.h>
57
58int	fflag;				/* Unlink existing files. */
59int	sflag;				/* Symbolic, not hard, link. */
60int	vflag;				/* Verbose output. */
61					/* System link call. */
62int (*linkf) __P((const char *, const char *));
63char	linkch;
64
65int	linkit __P((char *, char *, int));
66void	usage __P((void));
67
68int
69main(argc, argv)
70	int argc;
71	char *argv[];
72{
73	extern int optind;
74	struct stat sb;
75	int ch, exitval;
76	char *sourcedir;
77
78	while ((ch = getopt(argc, argv, "fsv")) != -1)
79		switch (ch) {
80		case 'f':
81			fflag = 1;
82			break;
83		case 's':
84			sflag = 1;
85			break;
86		case 'v':
87			vflag = 1;
88			break;
89		case '?':
90		default:
91			usage();
92		}
93
94	argv += optind;
95	argc -= optind;
96
97	linkf = sflag ? symlink : link;
98	linkch = sflag ? '-' : '=';
99
100	switch(argc) {
101	case 0:
102		usage();
103	case 1:				/* ln target */
104		exit(linkit(argv[0], ".", 1));
105	case 2:				/* ln target source */
106		exit(linkit(argv[0], argv[1], 0));
107	}
108					/* ln target1 target2 directory */
109	sourcedir = argv[argc - 1];
110	if (stat(sourcedir, &sb))
111		err(1, "%s", sourcedir);
112	if (!S_ISDIR(sb.st_mode))
113		usage();
114	for (exitval = 0; *argv != sourcedir; ++argv)
115		exitval |= linkit(*argv, sourcedir, 1);
116	exit(exitval);
117}
118
119int
120linkit(target, source, isdir)
121	char *target, *source;
122	int isdir;
123{
124	struct stat sb;
125	int exists;
126	char *p, path[MAXPATHLEN];
127
128	if (!sflag) {
129		/* If target doesn't exist, quit now. */
130		if (stat(target, &sb)) {
131			warn("%s", target);
132			return (1);
133		}
134		/* Only symbolic links to directories. */
135		if (S_ISDIR(sb.st_mode)) {
136			errno = EISDIR;
137			warn("%s", target);
138			return (1);
139		}
140	}
141
142	/* If the source is a directory, append the target's name. */
143	if (isdir || ((exists = !stat(source, &sb)) && S_ISDIR(sb.st_mode))) {
144		if ((p = strrchr(target, '/')) == NULL)
145			p = target;
146		else
147			++p;
148		(void)snprintf(path, sizeof(path), "%s/%s", source, p);
149		source = path;
150		exists = !lstat(source, &sb);
151	} else
152		exists = !lstat(source, &sb);
153
154	/*
155	 * If the file exists, and -f was specified, unlink it.
156	 * Attempt the link.
157	 */
158	if ((fflag && exists && unlink(source)) || (*linkf)(target, source)) {
159		warn("%s", source);
160		return (1);
161	}
162	if (vflag)
163		(void)printf("%s %c> %s\n", source, linkch, target);
164	return (0);
165}
166
167void
168usage()
169{
170	(void)fprintf(stderr, "%s\n%s\n",
171	    "usage: ln [-fsv] file1 file2",
172	    "       ln [-fsv] file ... directory");
173	exit(1);
174}
175