xref: /freebsd/bin/ln/ln.c (revision cb166ce422ac2bc81f42c2a2e2cd68625c11478d)
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   "$FreeBSD$";
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 int	vflag;				/* Verbose output. */
61 					/* System link call. */
62 int (*linkf) __P((const char *, const char *));
63 char	linkch;
64 
65 int	linkit __P((char *, char *, int));
66 void	usage __P((void));
67 
68 int
69 main(argc, argv)
70 	int argc;
71 	char *argv[];
72 {
73 	extern int optind;
74 	struct stat sb;
75 	int ch, exitval;
76 	char *p, *sourcedir;
77 
78 	/*
79 	 * Test for the special case where the utility is called as
80 	 * "link", for which the functionality provided is greatly
81 	 * simplified.
82 	 */
83 	if ((p = rindex(argv[0], '/')) == NULL)
84 		p = argv[0];
85 	else
86 		++p;
87 	if (strcmp(p, "link") == 0) {
88 		if (argc == 3) {
89 			linkf = link;
90 			exit(linkit(argv[1], argv[2], 0));
91 		} else
92 			usage();
93 	}
94 
95 	while ((ch = getopt(argc, argv, "fsv")) != -1)
96 		switch (ch) {
97 		case 'f':
98 			fflag = 1;
99 			break;
100 		case 's':
101 			sflag = 1;
102 			break;
103 		case 'v':
104 			vflag = 1;
105 			break;
106 		case '?':
107 		default:
108 			usage();
109 		}
110 
111 	argv += optind;
112 	argc -= optind;
113 
114 	linkf = sflag ? symlink : link;
115 	linkch = sflag ? '-' : '=';
116 
117 	switch(argc) {
118 	case 0:
119 		usage();
120 	case 1:				/* ln target */
121 		exit(linkit(argv[0], ".", 1));
122 	case 2:				/* ln target source */
123 		exit(linkit(argv[0], argv[1], 0));
124 	}
125 					/* ln target1 target2 directory */
126 	sourcedir = argv[argc - 1];
127 	if (stat(sourcedir, &sb))
128 		err(1, "%s", sourcedir);
129 	if (!S_ISDIR(sb.st_mode))
130 		usage();
131 	for (exitval = 0; *argv != sourcedir; ++argv)
132 		exitval |= linkit(*argv, sourcedir, 1);
133 	exit(exitval);
134 }
135 
136 int
137 linkit(target, source, isdir)
138 	char *target, *source;
139 	int isdir;
140 {
141 	struct stat sb;
142 	int exists;
143 	char *p, path[MAXPATHLEN];
144 
145 	if (!sflag) {
146 		/* If target doesn't exist, quit now. */
147 		if (stat(target, &sb)) {
148 			warn("%s", target);
149 			return (1);
150 		}
151 		/* Only symbolic links to directories. */
152 		if (S_ISDIR(sb.st_mode)) {
153 			errno = EISDIR;
154 			warn("%s", target);
155 			return (1);
156 		}
157 	}
158 
159 	/* If the source is a directory, append the target's name. */
160 	if (isdir || ((exists = !stat(source, &sb)) && S_ISDIR(sb.st_mode))) {
161 		if ((p = strrchr(target, '/')) == NULL)
162 			p = target;
163 		else
164 			++p;
165 		(void)snprintf(path, sizeof(path), "%s/%s", source, p);
166 		source = path;
167 		exists = !lstat(source, &sb);
168 	} else
169 		exists = !lstat(source, &sb);
170 
171 	/*
172 	 * If the file exists, and -f was specified, unlink it.
173 	 * Attempt the link.
174 	 */
175 	if ((fflag && exists && unlink(source)) || (*linkf)(target, source)) {
176 		warn("%s", source);
177 		return (1);
178 	}
179 	if (vflag)
180 		(void)printf("%s %c> %s\n", source, linkch, target);
181 	return (0);
182 }
183 
184 void
185 usage()
186 {
187 	(void)fprintf(stderr, "%s\n%s\n%s\n",
188 	    "usage: ln [-fsv] file1 file2",
189 	    "       ln [-fsv] file ... directory",
190 	    "       link file1 file2");
191 	exit(1);
192 }
193