bin/ln/ln.c

   1 /* $NetBSD: ln.c,v 1.33 2008/05/26 14:21:08 christos 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\
  35  The Regents of the University of California.  All rights reserved.");
  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 1.33 2008/05/26 14:21:08 christos 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 <locale.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <unistd.h>
  56
  57 int     fflag;                          /* Unlink existing files. */
  58 int     hflag;                          /* Check new name for symlink first. */
  59 int     iflag;                          /* Interactive mode. */
  60 int     sflag;                          /* Symbolic, not hard, link. */
  61 int     vflag;                          /* Verbose output */
  62
  63                                         /* System link call. */
  64 int (*linkf)(const char *, const char *);
  65 char   linkch;
  66
  67 int     linkit(const char *, const char *, int);
  68 void    usage(void);
  69 int     main(int, char *[]);
  70
  71 int
  72 main(int argc, char *argv[])
  73 {
  74         struct stat sb;
  75         int ch, exitval;
  76         char *sourcedir;
  77
  78         setprogname(argv[0]);
  79         (void)setlocale(LC_ALL, "");
  80
  81         while ((ch = getopt(argc, argv, "fhinsv")) != -1)
  82                 switch (ch) {
  83                 case 'f':
  84                         fflag = 1;
  85                         iflag = 0;
  86                         break;
  87                 case 'h':
  88                 case 'n':
  89                         hflag = 1;
  90                         break;
  91                 case 'i':
  92                         iflag = 1;
  93                         fflag = 0;
  94                         break;
  95                 case 's':
  96                         sflag = 1;
  97                         break;
  98                 case 'v':
  99                         vflag = 1;
 100                         break;
 101                 case '?':
 102                 default:
 103                         usage();
 104                         /* NOTREACHED */
 105                 }
 106
 107         argv += optind;
 108         argc -= optind;
 109
 110         if (sflag) {
 111                 linkf  = symlink;
 112                 linkch = '-';
 113         } else {
 114                 linkf  = link;
 115                 linkch = '=';
 116         }
 117
 118         switch(argc) {
 119         case 0:
 120                 usage();
 121                 /* NOTREACHED */
 122         case 1:                         /* ln target */
 123                 exit(linkit(argv[0], ".", 1));
 124                 /* NOTREACHED */
 125         case 2:                         /* ln target source */
 126                 exit(linkit(argv[0], argv[1], 0));
 127                 /* NOTREACHED */
 128         }
 129
 130                                         /* ln target1 target2 directory */
 131         sourcedir = argv[argc - 1];
 132         if (hflag && lstat(sourcedir, &sb) == 0 && S_ISLNK(sb.st_mode)) {
 133                 /* we were asked not to follow symlinks, but found one at
 134                    the target--simulate "not a directory" error */
 135                 errno = ENOTDIR;
 136                 err(EXIT_FAILURE, "%s", sourcedir);
 137                 /* NOTREACHED */
 138         }
 139         if (stat(sourcedir, &sb)) {
 140                 err(EXIT_FAILURE, "%s", sourcedir);
 141                 /* NOTREACHED */
 142         }
 143         if (!S_ISDIR(sb.st_mode)) {
 144                 usage();
 145                 /* NOTREACHED */
 146         }
 147         for (exitval = 0; *argv != sourcedir; ++argv)
 148                 exitval |= linkit(*argv, sourcedir, 1);
 149         exit(exitval);
 150         /* NOTREACHED */
 151 }
 152
 153 int
 154 linkit(const char *target, const char *source, int isdir)
 155 {
 156         struct stat sb;
 157         const char *p;
 158         char path[MAXPATHLEN];
 159         int ch, exists, first;
 160
 161         if (!sflag) {
 162                 /* If target doesn't exist, quit now. */
 163                 if (stat(target, &sb)) {
 164                         warn("%s", target);
 165                         return (1);
 166                 }
 167         }
 168
 169         /* If the source is a directory (and not a symlink if hflag),
 170            append the target's name. */
 171         if (isdir ||
 172             (!lstat(source, &sb) && S_ISDIR(sb.st_mode)) ||
 173             (!hflag && !stat(source, &sb) && S_ISDIR(sb.st_mode))) {
 174                 if ((p = strrchr(target, '/')) == NULL)
 175                         p = target;
 176                 else
 177                         ++p;
 178                 (void)snprintf(path, sizeof(path), "%s/%s", source, p);
 179                 source = path;
 180         }
 181
 182         exists = !lstat(source, &sb);
 183
 184         /*
 185          * If the file exists, then unlink it forcibly if -f was specified
 186          * and interactively if -i was specified.
 187          */
 188         if (fflag && exists) {
 189                 if (unlink(source)) {
 190                         warn("%s", source);
 191                         return (1);
 192                 }
 193         } else if (iflag && exists) {
 194                 fflush(stdout);
 195                 (void)fprintf(stderr, "replace %s? ", source);
 196
 197                 first = ch = getchar();
 198                 while (ch != '\n' && ch != EOF)
 199                         ch = getchar();
 200                 if (first != 'y' && first != 'Y') {
 201                         (void)fprintf(stderr, "not replaced\n");
 202                         return (1);
 203                 }
 204
 205                 if (unlink(source)) {
 206                         warn("%s", source);
 207                         return (1);
 208                 }
 209         }
 210
 211         /* Attempt the link. */
 212         if ((*linkf)(target, source)) {
 213                 warn("%s", source);
 214                 return (1);
 215         }
 216         if (vflag)
 217                 (void)printf("%s %c> %s\n", source, linkch, target);
 218
 219         return (0);
 220 }
 221
 222 void
 223 usage(void)
 224 {
 225
 226         (void)fprintf(stderr,
 227             "usage:\t%s [-fhinsv] file1 file2\n\t%s [-fhinsv] file ... directory\n",
 228             getprogname(), getprogname());
 229         exit(1);
 230         /* NOTREACHED */
 231 }