xref: /freebsd/bin/ln/ln.c (revision 380a989b3223d455375b4fae70fd0b9bdd43bafb)
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
35 static 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
42 static char sccsid[] = "@(#)ln.c	8.2 (Berkeley) 3/31/94";
43 #endif
44 static const char rcsid[] =
45 	"$Id$";
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 
58 int	fflag;				/* Unlink existing files. */
59 int	sflag;				/* Symbolic, not hard, link. */
60 					/* System link call. */
61 int (*linkf) __P((const char *, const char *));
62 
63 int	linkit __P((char *, char *, int));
64 void	usage __P((void));
65 
66 int
67 main(argc, argv)
68 	int argc;
69 	char *argv[];
70 {
71 	extern int optind;
72 	struct stat sb;
73 	int ch, exitval;
74 	char *sourcedir;
75 
76 	while ((ch = getopt(argc, argv, "fs")) != -1)
77 		switch (ch) {
78 		case 'f':
79 			fflag = 1;
80 			break;
81 		case 's':
82 			sflag = 1;
83 			break;
84 		case '?':
85 		default:
86 			usage();
87 		}
88 
89 	argv += optind;
90 	argc -= optind;
91 
92 	linkf = sflag ? symlink : link;
93 
94 	switch(argc) {
95 	case 0:
96 		usage();
97 	case 1:				/* ln target */
98 		exit(linkit(argv[0], ".", 1));
99 	case 2:				/* ln target source */
100 		exit(linkit(argv[0], argv[1], 0));
101 	}
102 					/* ln target1 target2 directory */
103 	sourcedir = argv[argc - 1];
104 	if (stat(sourcedir, &sb))
105 		err(1, "%s", sourcedir);
106 	if (!S_ISDIR(sb.st_mode))
107 		usage();
108 	for (exitval = 0; *argv != sourcedir; ++argv)
109 		exitval |= linkit(*argv, sourcedir, 1);
110 	exit(exitval);
111 }
112 
113 int
114 linkit(target, source, isdir)
115 	char *target, *source;
116 	int isdir;
117 {
118 	struct stat sb;
119 	int exists;
120 	char *p, path[MAXPATHLEN];
121 
122 	if (!sflag) {
123 		/* If target doesn't exist, quit now. */
124 		if (stat(target, &sb)) {
125 			warn("%s", target);
126 			return (1);
127 		}
128 		/* Only symbolic links to directories. */
129 		if (S_ISDIR(sb.st_mode)) {
130 			errno = EISDIR;
131 			warn("%s", target);
132 			return (1);
133 		}
134 	}
135 
136 	/* If the source is a directory, append the target's name. */
137 	if (isdir || ((exists = !stat(source, &sb)) && S_ISDIR(sb.st_mode))) {
138 		if ((p = strrchr(target, '/')) == NULL)
139 			p = target;
140 		else
141 			++p;
142 		(void)snprintf(path, sizeof(path), "%s/%s", source, p);
143 		source = path;
144 		exists = !lstat(source, &sb);
145 	} else
146 		exists = !lstat(source, &sb);
147 
148 	/*
149 	 * If the file exists, and -f was specified, unlink it.
150 	 * Attempt the link.
151 	 */
152 	if ((fflag && exists && unlink(source)) || (*linkf)(target, source)) {
153 		warn("%s", source);
154 		return (1);
155 	}
156 	return (0);
157 }
158 
159 void
160 usage()
161 {
162 	(void)fprintf(stderr, "%s\n%s\n",
163 	    "usage: ln [-fs] file1 file2",
164 	    "       ln [-fs] file ... directory");
165 	exit(1);
166 }
167