xref: /freebsd/bin/ln/ln.c (revision c68159a6d8eede11766cf13896d0f7670dbd51aa)
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	iflag;				/* Interactive mode. */
60 int	sflag;				/* Symbolic, not hard, link. */
61 int	vflag;				/* Verbose output. */
62 					/* System link call. */
63 int (*linkf) __P((const char *, const char *));
64 char	linkch;
65 
66 int	linkit __P((char *, char *, int));
67 void	usage __P((void));
68 
69 int
70 main(argc, argv)
71 	int argc;
72 	char *argv[];
73 {
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, "fisv")) != -1)
96 		switch (ch) {
97 		case 'f':
98 			fflag = 1;
99 			iflag = 0;
100 			break;
101 		case 'i':
102 			iflag = 1;
103 			fflag = 0;
104 			break;
105 		case 's':
106 			sflag = 1;
107 			break;
108 		case 'v':
109 			vflag = 1;
110 			break;
111 		case '?':
112 		default:
113 			usage();
114 		}
115 
116 	argv += optind;
117 	argc -= optind;
118 
119 	linkf = sflag ? symlink : link;
120 	linkch = sflag ? '-' : '=';
121 
122 	switch(argc) {
123 	case 0:
124 		usage();
125 	case 1:				/* ln target */
126 		exit(linkit(argv[0], ".", 1));
127 	case 2:				/* ln target source */
128 		exit(linkit(argv[0], argv[1], 0));
129 	}
130 					/* ln target1 target2 directory */
131 	sourcedir = argv[argc - 1];
132 	if (stat(sourcedir, &sb))
133 		err(1, "%s", sourcedir);
134 	if (!S_ISDIR(sb.st_mode))
135 		usage();
136 	for (exitval = 0; *argv != sourcedir; ++argv)
137 		exitval |= linkit(*argv, sourcedir, 1);
138 	exit(exitval);
139 }
140 
141 int
142 linkit(target, source, isdir)
143 	char *target, *source;
144 	int isdir;
145 {
146 	struct stat sb;
147 	int ch, exists, first;
148 	char *p, path[MAXPATHLEN];
149 
150 	if (!sflag) {
151 		/* If target doesn't exist, quit now. */
152 		if (stat(target, &sb)) {
153 			warn("%s", target);
154 			return (1);
155 		}
156 		/* Only symbolic links to directories. */
157 		if (S_ISDIR(sb.st_mode)) {
158 			errno = EISDIR;
159 			warn("%s", target);
160 			return (1);
161 		}
162 	}
163 
164 	/* If the source is a directory, append the target's name. */
165 	if (isdir || ((exists = !stat(source, &sb)) && S_ISDIR(sb.st_mode))) {
166 		if ((p = strrchr(target, '/')) == NULL)
167 			p = target;
168 		else
169 			++p;
170 		(void)snprintf(path, sizeof(path), "%s/%s", source, p);
171 		source = path;
172 		exists = !lstat(source, &sb);
173 	} else
174 		exists = !lstat(source, &sb);
175 
176 	/*
177 	 * If the file exists, then unlink it forcibly if -f was specified
178 	 * and interactively if -i was specified.
179 	 */
180 	if (fflag && exists) {
181 		if (unlink(source)) {
182 			warn("%s", source);
183 			return (1);
184 		}
185 	} else if (iflag && exists) {
186 		fflush(stdout);
187 		fprintf(stderr, "replace %s? ", source);
188 
189 		first = ch = getchar();
190 		while(ch != '\n' && ch != EOF)
191 			ch = getchar();
192 		if (first != 'y' && first != 'Y') {
193 			fprintf(stderr, "not replaced\n");
194 			return (1);
195 		}
196 
197 		if (unlink(source)) {
198 			warn("%s", source);
199 			return (1);
200 		}
201 	}
202 
203 	/* Attempt the link. */
204 	if ((*linkf)(target, source)) {
205 		warn("%s", source);
206 		return (1);
207 	}
208 	if (vflag)
209 		(void)printf("%s %c> %s\n", source, linkch, target);
210 	return (0);
211 }
212 
213 void
214 usage()
215 {
216 	(void)fprintf(stderr, "%s\n%s\n%s\n",
217 	    "usage: ln [-fisv] file1 file2",
218 	    "       ln [-fisv] file ... directory",
219 	    "       link file1 file2");
220 	exit(1);
221 }
222