xref: /netbsd-src/bin/ln/ln.c (revision e77448e07be3174235c13f58032a0d6d0ab7638d)
1 /* $NetBSD: ln.c,v 1.32 2006/10/13 20:37:10 wiz Exp $ */
2 
3 /*
4  * Copyright (c) 1987, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT("@(#) Copyright (c) 1987, 1993, 1994\n\
35 	The Regents of the University of California.  All rights reserved.\n");
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)ln.c	8.2 (Berkeley) 3/31/94";
41 #else
42 __RCSID("$NetBSD: ln.c,v 1.32 2006/10/13 20:37:10 wiz Exp $");
43 #endif
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 
56 int	fflag;				/* Unlink existing files. */
57 int	hflag;				/* Check new name for symlink first. */
58 int	iflag;				/* Interactive mode. */
59 int	sflag;				/* Symbolic, not hard, link. */
60 int	vflag;                          /* Verbose output */
61 
62 					/* System link call. */
63 int (*linkf)(const char *, const char *);
64 char   linkch;
65 
66 int	linkit(const char *, const char *, int);
67 void	usage(void);
68 int	main(int, char *[]);
69 
70 int
71 main(int argc, char *argv[])
72 {
73 	struct stat sb;
74 	int ch, exitval;
75 	char *sourcedir;
76 
77 	setprogname(argv[0]);
78 	while ((ch = getopt(argc, argv, "fhinsv")) != -1)
79 		switch (ch) {
80 		case 'f':
81 			fflag = 1;
82 			iflag = 0;
83 			break;
84 		case 'h':
85 		case 'n':
86 			hflag = 1;
87 			break;
88 		case 'i':
89 			iflag = 1;
90 			fflag = 0;
91 			break;
92 		case 's':
93 			sflag = 1;
94 			break;
95 		case 'v':
96 			vflag = 1;
97 			break;
98 		case '?':
99 		default:
100 			usage();
101 			/* NOTREACHED */
102 		}
103 
104 	argv += optind;
105 	argc -= optind;
106 
107 	if (sflag) {
108 		linkf  = symlink;
109 		linkch = '-';
110 	} else {
111 		linkf  = link;
112 		linkch = '=';
113 	}
114 
115 	switch(argc) {
116 	case 0:
117 		usage();
118 		/* NOTREACHED */
119 	case 1:				/* ln target */
120 		exit(linkit(argv[0], ".", 1));
121 		/* NOTREACHED */
122 	case 2:				/* ln target source */
123 		exit(linkit(argv[0], argv[1], 0));
124 		/* NOTREACHED */
125 	}
126 
127 					/* ln target1 target2 directory */
128 	sourcedir = argv[argc - 1];
129 	if (hflag && lstat(sourcedir, &sb) == 0 && S_ISLNK(sb.st_mode)) {
130 		/* we were asked not to follow symlinks, but found one at
131 		   the target--simulate "not a directory" error */
132 		errno = ENOTDIR;
133 		err(EXIT_FAILURE, "%s", sourcedir);
134 		/* NOTREACHED */
135 	}
136 	if (stat(sourcedir, &sb)) {
137 		err(EXIT_FAILURE, "%s", sourcedir);
138 		/* NOTREACHED */
139 	}
140 	if (!S_ISDIR(sb.st_mode)) {
141 		usage();
142 		/* NOTREACHED */
143 	}
144 	for (exitval = 0; *argv != sourcedir; ++argv)
145 		exitval |= linkit(*argv, sourcedir, 1);
146 	exit(exitval);
147 	/* NOTREACHED */
148 }
149 
150 int
151 linkit(const char *target, const char *source, int isdir)
152 {
153 	struct stat sb;
154 	const char *p;
155 	char path[MAXPATHLEN];
156 	int ch, exists, first;
157 
158 	if (!sflag) {
159 		/* If target doesn't exist, quit now. */
160 		if (stat(target, &sb)) {
161 			warn("%s", target);
162 			return (1);
163 		}
164 	}
165 
166 	/* If the source is a directory (and not a symlink if hflag),
167 	   append the target's name. */
168 	if (isdir ||
169 	    (!lstat(source, &sb) && S_ISDIR(sb.st_mode)) ||
170 	    (!hflag && !stat(source, &sb) && S_ISDIR(sb.st_mode))) {
171 		if ((p = strrchr(target, '/')) == NULL)
172 			p = target;
173 		else
174 			++p;
175 		(void)snprintf(path, sizeof(path), "%s/%s", source, p);
176 		source = path;
177 	}
178 
179 	exists = !lstat(source, &sb);
180 
181 	/*
182 	 * If the file exists, then unlink it forcibly if -f was specified
183 	 * and interactively if -i was specified.
184 	 */
185 	if (fflag && exists) {
186 		if (unlink(source)) {
187 			warn("%s", source);
188 			return (1);
189 		}
190 	} else if (iflag && exists) {
191 		fflush(stdout);
192 		(void)fprintf(stderr, "replace %s? ", source);
193 
194 		first = ch = getchar();
195 		while (ch != '\n' && ch != EOF)
196 			ch = getchar();
197 		if (first != 'y' && first != 'Y') {
198 			(void)fprintf(stderr, "not replaced\n");
199 			return (1);
200 		}
201 
202 		if (unlink(source)) {
203 			warn("%s", source);
204 			return (1);
205 		}
206 	}
207 
208 	/* Attempt the link. */
209 	if ((*linkf)(target, source)) {
210 		warn("%s", source);
211 		return (1);
212 	}
213 	if (vflag)
214 		(void)printf("%s %c> %s\n", source, linkch, target);
215 
216 	return (0);
217 }
218 
219 void
220 usage(void)
221 {
222 
223 	(void)fprintf(stderr,
224 	    "usage:\t%s [-fhinsv] file1 file2\n\t%s [-fhinsv] file ... directory\n",
225 	    getprogname(), getprogname());
226 	exit(1);
227 	/* NOTREACHED */
228 }
229