bin/ln/ln.c

   1 /* $NetBSD: ln.c,v 1.35 2011/08/29 14:38:30 joerg 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 1.35 2011/08/29 14:38:30 joerg 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 static int      fflag;                          /* Unlink existing files. */
  58 static int      hflag;                          /* Check new name for symlink first. */
  59 static int      iflag;                          /* Interactive mode. */
  60 static int      sflag;                          /* Symbolic, not hard, link. */
  61 static int      vflag;                          /* Verbose output */
  62
  63                                         /* System link call. */
  64 static int (*linkf)(const char *, const char *);
  65 static char   linkch;
  66
  67 static int      linkit(const char *, const char *, int);
  68 __dead static void      usage(void);
  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         (void)setlocale(LC_ALL, "");
  79
  80         while ((ch = getopt(argc, argv, "fhinsv")) != -1)
  81                 switch (ch) {
  82                 case 'f':
  83                         fflag = 1;
  84                         iflag = 0;
  85                         break;
  86                 case 'h':
  87                 case 'n':
  88                         hflag = 1;
  89                         break;
  90                 case 'i':
  91                         iflag = 1;
  92                         fflag = 0;
  93                         break;
  94                 case 's':
  95                         sflag = 1;
  96                         break;
  97                 case 'v':
  98                         vflag = 1;
  99                         break;
 100                 case '?':
 101                 default:
 102                         usage();
 103                         /* NOTREACHED */
 104                 }
 105
 106         argv += optind;
 107         argc -= optind;
 108
 109         if (sflag) {
 110                 linkf  = symlink;
 111                 linkch = '-';
 112         } else {
 113                 linkf  = link;
 114                 linkch = '=';
 115         }
 116
 117         switch(argc) {
 118         case 0:
 119                 usage();
 120                 /* NOTREACHED */
 121         case 1:                         /* ln target */
 122                 exit(linkit(argv[0], ".", 1));
 123                 /* NOTREACHED */
 124         case 2:                         /* ln target source */
 125                 exit(linkit(argv[0], argv[1], 0));
 126                 /* NOTREACHED */
 127         }
 128
 129                                         /* ln target1 target2 directory */
 130         sourcedir = argv[argc - 1];
 131         if (hflag && lstat(sourcedir, &sb) == 0 && S_ISLNK(sb.st_mode)) {
 132                 /* we were asked not to follow symlinks, but found one at
 133                    the target--simulate "not a directory" error */
 134                 errno = ENOTDIR;
 135                 err(EXIT_FAILURE, "%s", sourcedir);
 136                 /* NOTREACHED */
 137         }
 138         if (stat(sourcedir, &sb)) {
 139                 err(EXIT_FAILURE, "%s", sourcedir);
 140                 /* NOTREACHED */
 141         }
 142         if (!S_ISDIR(sb.st_mode)) {
 143                 usage();
 144                 /* NOTREACHED */
 145         }
 146         for (exitval = 0; *argv != sourcedir; ++argv)
 147                 exitval |= linkit(*argv, sourcedir, 1);
 148         exit(exitval);
 149         /* NOTREACHED */
 150 }
 151
 152 static int
 153 linkit(const char *target, const char *source, int isdir)
 154 {
 155         struct stat sb;
 156         const char *p;
 157         char path[MAXPATHLEN];
 158         int ch, exists, first;
 159
 160         if (!sflag) {
 161                 /* If target doesn't exist, quit now. */
 162                 if (stat(target, &sb)) {
 163                         warn("%s", target);
 164                         return (1);
 165                 }
 166         }
 167
 168         /* If the source is a directory (and not a symlink if hflag),
 169            append the target's name. */
 170         if (isdir ||
 171             (!lstat(source, &sb) && S_ISDIR(sb.st_mode)) ||
 172             (!hflag && !stat(source, &sb) && S_ISDIR(sb.st_mode))) {
 173                 if ((p = strrchr(target, '/')) == NULL)
 174                         p = target;
 175                 else
 176                         ++p;
 177                 (void)snprintf(path, sizeof(path), "%s/%s", source, p);
 178                 source = path;
 179         }
 180
 181         exists = !lstat(source, &sb);
 182
 183         /*
 184          * If the file exists, then unlink it forcibly if -f was specified
 185          * and interactively if -i was specified.
 186          */
 187         if (fflag && exists) {
 188                 if (unlink(source)) {
 189                         warn("%s", source);
 190                         return (1);
 191                 }
 192         } else if (iflag && exists) {
 193                 fflush(stdout);
 194                 (void)fprintf(stderr, "replace %s? ", source);
 195
 196                 first = ch = getchar();
 197                 while (ch != '\n' && ch != EOF)
 198                         ch = getchar();
 199                 if (first != 'y' && first != 'Y') {
 200                         (void)fprintf(stderr, "not replaced\n");
 201                         return (1);
 202                 }
 203
 204                 if (unlink(source)) {
 205                         warn("%s", source);
 206                         return (1);
 207                 }
 208         }
 209
 210         /* Attempt the link. */
 211         if ((*linkf)(target, source)) {
 212                 warn("%s", source);
 213                 return (1);
 214         }
 215         if (vflag)
 216                 (void)printf("%s %c> %s\n", source, linkch, target);
 217
 218         return (0);
 219 }
 220
 221 static void
 222 usage(void)
 223 {
 224
 225         (void)fprintf(stderr,
 226             "usage:\t%s [-fhinsv] file1 file2\n\t%s [-fhinsv] file ... directory\n",
 227             getprogname(), getprogname());
 228         exit(1);
 229         /* NOTREACHED */
 230 }