ln/ln.c

   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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if 0
  31 #ifndef lint
  32 static char const copyright[] =
  33 "@(#) Copyright (c) 1987, 1993, 1994\n\
  34         The Regents of the University of California.  All rights reserved.\n";
  35 #endif /* not lint */
  36
  37 #ifndef lint
  38 static char sccsid[] = "@(#)ln.c        8.2 (Berkeley) 3/31/94";
  39 #endif /* not lint */
  40 #endif
  41 #include <sys/cdefs.h>
  42 __FBSDID("$FreeBSD: src/bin/ln/ln.c,v 1.34 2006/02/14 11:08:05 glebius Exp $");
  43
  44 #include <sys/param.h>
  45 #include <sys/stat.h>
  46
  47 #include <err.h>
  48 #include <errno.h>
  49 #include <libgen.h>
  50 #include <limits.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     Fflag;                          /* Remove empty directories also. */
  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                                         /* 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
  69 int
  70 main(int argc, char *argv[])
  71 {
  72         struct stat sb;
  73         char *p, *sourcedir;
  74         int ch, exitval;
  75
  76         if (argc < 1)
  77                 usage();
  78         /*
  79          * Test for the special case where the utility is called as
  80          * "link", for which the functionality provided is greatly
  81          * simplified.
  82          */
  83         if ((p = rindex(argv[0], '/')) == NULL)
  84                 p = argv[0];
  85         else
  86                 ++p;
  87         if (strcmp(p, "link") == 0) {
  88                 while (getopt(argc, argv, "") != -1)
  89                         usage();
  90                 argc -= optind;
  91                 argv += optind;
  92                 if (argc != 2)
  93                         usage();
  94                 linkf = link;
  95                 exit(linkit(argv[0], argv[1], 0));
  96         }
  97
  98         while ((ch = getopt(argc, argv, "Ffhinsv")) != -1)
  99                 switch (ch) {
 100                 case 'F':
 101                         Fflag = 1;
 102                         break;
 103                 case 'f':
 104                         fflag = 1;
 105                         iflag = 0;
 106                         break;
 107                 case 'h':
 108                 case 'n':
 109                         hflag = 1;
 110                         break;
 111                 case 'i':
 112                         iflag = 1;
 113                         fflag = 0;
 114                         break;
 115                 case 's':
 116                         sflag = 1;
 117                         break;
 118                 case 'v':
 119                         vflag = 1;
 120                         break;
 121                 case '?':
 122                 default:
 123                         usage();
 124                 }
 125
 126         argv += optind;
 127         argc -= optind;
 128
 129         linkf = sflag ? symlink : link;
 130         linkch = sflag ? '-' : '=';
 131         if (sflag == 0)
 132                 Fflag = 0;
 133         if (Fflag == 1 && iflag == 0)
 134                 fflag = 1;
 135
 136         switch(argc) {
 137         case 0:
 138                 usage();
 139                 /* NOTREACHED */
 140         case 1:                         /* ln target */
 141                 exit(linkit(argv[0], ".", 1));
 142         case 2:                         /* ln target source */
 143                 exit(linkit(argv[0], argv[1], 0));
 144         default:
 145                 ;
 146         }
 147                                         /* ln target1 target2 directory */
 148         sourcedir = argv[argc - 1];
 149         if (hflag && lstat(sourcedir, &sb) == 0 && S_ISLNK(sb.st_mode)) {
 150                 /*
 151                  * We were asked not to follow symlinks, but found one at
 152                  * the target--simulate "not a directory" error
 153                  */
 154                 errno = ENOTDIR;
 155                 err(1, "%s", sourcedir);
 156         }
 157         if (stat(sourcedir, &sb))
 158                 err(1, "%s", sourcedir);
 159         if (!S_ISDIR(sb.st_mode))
 160                 usage();
 161         for (exitval = 0; *argv != sourcedir; ++argv)
 162                 exitval |= linkit(*argv, sourcedir, 1);
 163         exit(exitval);
 164 }
 165
 166 int
 167 linkit(const char *target, const char *source, int isdir)
 168 {
 169         struct stat sb;
 170         const char *p;
 171         int ch, exists, first;
 172         char path[PATH_MAX];
 173         char bbuf[PATH_MAX];
 174
 175         if (!sflag) {
 176                 /* If target doesn't exist, quit now. */
 177                 if (stat(target, &sb)) {
 178                         warn("%s", target);
 179                         return (1);
 180                 }
 181                 /* Only symbolic links to directories. */
 182                 if (S_ISDIR(sb.st_mode)) {
 183                         errno = EISDIR;
 184                         warn("%s", target);
 185                         return (1);
 186                 }
 187         }
 188
 189         /*
 190          * If the source is a directory (and not a symlink if hflag),
 191          * append the target's name.
 192          */
 193         if (isdir ||
 194             (lstat(source, &sb) == 0 && S_ISDIR(sb.st_mode)) ||
 195             (!hflag && stat(source, &sb) == 0 && S_ISDIR(sb.st_mode))) {
 196                 if (strlcpy(bbuf, target, sizeof(bbuf)) >= sizeof(bbuf) ||
 197                     (p = basename(bbuf)) == NULL ||
 198                     snprintf(path, sizeof(path), "%s/%s", source, p) >=
 199                     (ssize_t)sizeof(path)) {
 200                         errno = ENAMETOOLONG;
 201                         warn("%s", target);
 202                         return (1);
 203                 }
 204                 source = path;
 205         }
 206
 207         exists = !lstat(source, &sb);
 208         /*
 209          * If the file exists, then unlink it forcibly if -f was specified
 210          * and interactively if -i was specified.
 211          */
 212         if (fflag && exists) {
 213                 if (Fflag && S_ISDIR(sb.st_mode)) {
 214                         if (rmdir(source)) {
 215                                 warn("%s", source);
 216                                 return (1);
 217                         }
 218                 } else if (unlink(source)) {
 219                         warn("%s", source);
 220                         return (1);
 221                 }
 222         } else if (iflag && exists) {
 223                 fflush(stdout);
 224                 fprintf(stderr, "replace %s? ", source);
 225
 226                 first = ch = getchar();
 227                 while(ch != '\n' && ch != EOF)
 228                         ch = getchar();
 229                 if (first != 'y' && first != 'Y') {
 230                         fprintf(stderr, "not replaced\n");
 231                         return (1);
 232                 }
 233
 234                 if (Fflag && S_ISDIR(sb.st_mode)) {
 235                         if (rmdir(source)) {
 236                                 warn("%s", source);
 237                                 return (1);
 238                         }
 239                 } else if (unlink(source)) {
 240                         warn("%s", source);
 241                         return (1);
 242                 }
 243         }
 244
 245         /* Attempt the link. */
 246         if ((*linkf)(target, source)) {
 247                 warn("%s", source);
 248                 return (1);
 249         }
 250         if (vflag)
 251                 (void)printf("%s %c> %s\n", source, linkch, target);
 252         return (0);
 253 }
 254
 255 void
 256 usage(void)
 257 {
 258         (void)fprintf(stderr, "%s\n%s\n%s\n",
 259             "usage: ln [-Ffhinsv] source_file [target_file]",
 260             "       ln [-Ffhinsv] source_file ... target_dir",
 261             "       link source_file target_file");
 262         exit(1);
 263 }