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ln.c revision 1.1.1.2 
      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 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 static char sccsid[] = "@(#)ln.c	8.2 (Berkeley) 3/31/94";
     42 #endif /* not lint */
     43 
     44 #include <sys/param.h>
     45 #include <sys/stat.h>
     46 
     47 #include <err.h>
     48 #include <errno.h>
     49 #include <stdio.h>
     50 #include <stdlib.h>
     51 #include <string.h>
     52 #include <unistd.h>
     53 
     54 int	dirflag;			/* Undocumented directory flag. */
     55 int	fflag;				/* Unlink existing files. */
     56 int	sflag;				/* Symbolic, not hard, link. */
     57 					/* System link call. */
     58 int (*linkf) __P((const char *, const char *));
     59 
     60 int	linkit __P((char *, char *, int));
     61 void	usage __P((void));
     62 
     63 int
     64 main(argc, argv)
     65 	int argc;
     66 	char *argv[];
     67 {
     68 	extern int optind;
     69 	struct stat sb;
     70 	int ch, exitval;
     71 	char *sourcedir;
     72 
     73 	while ((ch = getopt(argc, argv, "Ffs")) != EOF)
     74 		switch (ch) {
     75 		case 'F':
     76 			dirflag = 1;	/* XXX: deliberately undocumented. */
     77 			break;
     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, unless -F option used. */
    129 		if (!dirflag && (sb.st_mode & S_IFMT) == S_IFDIR) {
    130 			warnx("%s: is a directory", target);
    131 			return (1);
    132 		}
    133 	}
    134 
    135 	/* If the source is a directory, append the target's name. */
    136 	if (isdir || (exists = !stat(source, &sb)) && S_ISDIR(sb.st_mode)) {
    137 		if ((p = strrchr(target, '/')) == NULL)
    138 			p = target;
    139 		else
    140 			++p;
    141 		(void)snprintf(path, sizeof(path), "%s/%s", source, p);
    142 		source = path;
    143 		exists = !stat(source, &sb);
    144 	} else
    145 		exists = !stat(source, &sb);
    146 
    147 	/*
    148 	 * If the file exists, and -f was specified, unlink it.
    149 	 * Attempt the link.
    150 	 */
    151 	if (fflag && exists && unlink(source) || (*linkf)(target, source)) {
    152 		warn("%s", source);
    153 		return (1);
    154 	}
    155 	return (0);
    156 }
    157 
    158 void
    159 usage()
    160 {
    161 	(void)fprintf(stderr,
    162 	    "usage:\tln [-fs] file1 file2\n\tln [-fs] file ... directory\n");
    163 	exit(1);
    164 }
    165