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ln.c revision 1.5 
      1 /*
      2  * Copyright (c) 1987 Regents of the University of California.
      3  * 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 char copyright[] =
     36 "@(#) Copyright (c) 1987 Regents of the University of California.\n\
     37  All rights reserved.\n";
     38 #endif /* not lint */
     39 
     40 #ifndef lint
     41 /*static char sccsid[] = "from: @(#)ln.c	4.15 (Berkeley) 2/24/91";*/
     42 static char rcsid[] = "$Id: ln.c,v 1.5 1993/08/17 01:03:51 jtc Exp $";
     43 #endif /* not lint */
     44 
     45 #include <sys/param.h>
     46 #include <sys/stat.h>
     47 #include <stdio.h>
     48 #include <errno.h>
     49 #include <string.h>
     50 #include <stdlib.h>
     51 #include <unistd.h>
     52 
     53 static int	forceflag,		/* force link by removing target */
     54 		dirflag,		/* allow hard links to directories */
     55 		sflag,			/* symbolic, not hard, link */
     56 		(*linkf)();		/* system link call */
     57 static linkit(), usage();
     58 
     59 main(argc, argv)
     60 	int argc;
     61 	char **argv;
     62 {
     63 	extern int optind;
     64 	struct stat buf;
     65 	int ch, exitval, link(), symlink();
     66 	char *sourcedir;
     67 
     68 	while ((ch = getopt(argc, argv, "fFs")) != EOF)
     69 		switch((char)ch) {
     70 		case 'f':
     71 			forceflag = 1;
     72 			break;
     73 		case 'F':
     74 			dirflag = 1;
     75 			break;
     76 		case 's':
     77 			sflag = 1;
     78 			break;
     79 		case '?':
     80 		default:
     81 			usage();
     82 		}
     83 
     84 	argv += optind;
     85 	argc -= optind;
     86 
     87 	linkf = sflag ? symlink : link;
     88 
     89 	switch(argc) {
     90 	case 0:
     91 		usage();
     92 	case 1:				/* ln target */
     93 		exit(linkit(argv[0], ".", 1));
     94 	case 2:				/* ln target source */
     95 		exit(linkit(argv[0], argv[1], 0));
     96 	default:			/* ln target1 target2 directory */
     97 		sourcedir = argv[argc - 1];
     98 		if (stat(sourcedir, &buf)) {
     99 			(void)fprintf(stderr,
    100 			    "ln: %s: %s\n", sourcedir, strerror(errno));
    101 			exit(1);
    102 		}
    103 		if (!S_ISDIR(buf.st_mode))
    104 			usage();
    105 		for (exitval = 0; *argv != sourcedir; ++argv)
    106 			exitval |= linkit(*argv, sourcedir, 1);
    107 		exit(exitval);
    108 	}
    109 	/* NOTREACHED */
    110 }
    111 
    112 static
    113 linkit(source, target, isdir)
    114 	char *source, *target;
    115 	int isdir;
    116 {
    117 	struct stat buf;
    118 	char path[MAXPATHLEN], *cp;
    119 
    120 	if (!sflag) {
    121 		/* if source doesn't exist, quit now */
    122 		if (stat(source, &buf)) {
    123 			(void)fprintf(stderr,
    124 			    "ln: %s: %s\n", source, strerror(errno));
    125 			return(1);
    126 		}
    127 		/* only symbolic links to directories, unless -F option used */
    128 		if (!dirflag && (buf.st_mode & S_IFMT) == S_IFDIR) {
    129 			(void)printf("ln: %s is a directory.\n", source);
    130 			return(1);
    131 		}
    132 	}
    133 
    134 	/* if the target is a directory, append the source's name */
    135 	if (isdir || !stat(target, &buf) && S_ISDIR(buf.st_mode)) {
    136 		if (!(cp = rindex(source, '/')))
    137 			cp = source;
    138 		else
    139 			++cp;
    140 		(void)sprintf(path, "%s/%s", target, cp);
    141 		target = path;
    142 	}
    143 
    144 	/* Remove existing file if -f is was specified */
    145 	if (forceflag && unlink (target) && errno != ENOENT) {
    146 		(void)fprintf(stderr, "ln: %s: %s\n", target, strerror(errno));
    147 		return (1);
    148 	}
    149 
    150 	if ((*linkf)(source, target)) {
    151 		(void)fprintf(stderr, "ln: %s: %s\n", target, strerror(errno));
    152 		return(1);
    153 	}
    154 	return(0);
    155 }
    156 
    157 static
    158 usage()
    159 {
    160 	(void)fprintf(stderr,
    161 	    "usage:\tln [-fs] file1 file2\n\tln [-fs] file ... directory\n");
    162 	exit(1);
    163 }
    164