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 <limits.h>
  50 #include <stdio.h>
  51 #include <stdlib.h>
  52 #include <string.h>
  53 #include <unistd.h>
  54
  55 int     fflag;                          /* Unlink existing files. */
  56 int     Fflag;                          /* Remove empty directories also. */
  57 int     hflag;                          /* Check new name for symlink first. */
  58 int     iflag;                          /* Interactive mode. */
  59 int     sflag;                          /* Symbolic, not hard, link. */
  60 int     vflag;                          /* Verbose output. */
  61                                         /* System link call. */
  62 int (*linkf)(const char *, const char *);
  63 char    linkch;
  64
  65 int     linkit(const char *, const char *, int);
  66 void    usage(void);
  67
  68 int
  69 main(int argc, char *argv[])
  70 {
  71         struct stat sb;
  72         char *p, *sourcedir;
  73         int ch, exitval;
  74
  75         if (argc < 1)
  76                 usage();
  77         /*
  78          * Test for the special case where the utility is called as
  79          * "link", for which the functionality provided is greatly
  80          * simplified.
  81          */
  82         if ((p = rindex(argv[0], '/')) == NULL)
  83                 p = argv[0];
  84         else
  85                 ++p;
  86         if (strcmp(p, "link") == 0) {
  87                 while (getopt(argc, argv, "") != -1)
  88                         usage();
  89                 argc -= optind;
  90                 argv += optind;
  91                 if (argc != 2)
  92                         usage();
  93                 linkf = link;
  94                 exit(linkit(argv[0], argv[1], 0));
  95         }
  96
  97         while ((ch = getopt(argc, argv, "Ffhinsv")) != -1)
  98                 switch (ch) {
  99                 case 'F':
 100                         Fflag = 1;
 101                         break;
 102                 case 'f':
 103                         fflag = 1;
 104                         iflag = 0;
 105                         break;
 106                 case 'h':
 107                 case 'n':
 108                         hflag = 1;
 109                         break;
 110                 case 'i':
 111                         iflag = 1;
 112                         fflag = 0;
 113                         break;
 114                 case 's':
 115                         sflag = 1;
 116                         break;
 117                 case 'v':
 118                         vflag = 1;
 119                         break;
 120                 case '?':
 121                 default:
 122                         usage();
 123                 }
 124
 125         argv += optind;
 126         argc -= optind;
 127
 128         linkf = sflag ? symlink : link;
 129         linkch = sflag ? '-' : '=';
 130         if (sflag == 0)
 131                 Fflag = 0;
 132         if (Fflag == 1 && iflag == 0)
 133                 fflag = 1;
 134
 135         switch(argc) {
 136         case 0:
 137                 usage();
 138                 /* NOTREACHED */
 139         case 1:                         /* ln target */
 140                 exit(linkit(argv[0], ".", 1));
 141         case 2:                         /* ln target source */
 142                 exit(linkit(argv[0], argv[1], 0));
 143         default:
 144                 ;
 145         }
 146                                         /* ln target1 target2 directory */
 147         sourcedir = argv[argc - 1];
 148         if (hflag && lstat(sourcedir, &sb) == 0 && S_ISLNK(sb.st_mode)) {
 149                 /*
 150                  * We were asked not to follow symlinks, but found one at
 151                  * the target--simulate "not a directory" error
 152                  */
 153                 errno = ENOTDIR;
 154                 err(1, "%s", sourcedir);
 155         }
 156         if (stat(sourcedir, &sb))
 157                 err(1, "%s", sourcedir);
 158         if (!S_ISDIR(sb.st_mode))
 159                 usage();
 160         for (exitval = 0; *argv != sourcedir; ++argv)
 161                 exitval |= linkit(*argv, sourcedir, 1);
 162         exit(exitval);
 163 }
 164
 165 int
 166 linkit(const char *target, const char *source, int isdir)
 167 {
 168         struct stat sb;
 169         const char *p;
 170         int ch, exists, first;
 171         char path[PATH_MAX];
 172
 173         if (!sflag) {
 174                 /* If target doesn't exist, quit now. */
 175                 if (stat(target, &sb)) {
 176                         warn("%s", target);
 177                         return (1);
 178                 }
 179                 /* Only symbolic links to directories. */
 180                 if (S_ISDIR(sb.st_mode)) {
 181                         errno = EISDIR;
 182                         warn("%s", target);
 183                         return (1);
 184                 }
 185         }
 186
 187         /*
 188          * If the source is a directory (and not a symlink if hflag),
 189          * append the target's name.
 190          */
 191         if (isdir ||
 192             (lstat(source, &sb) == 0 && S_ISDIR(sb.st_mode)) ||
 193             (!hflag && stat(source, &sb) == 0 && S_ISDIR(sb.st_mode))) {
 194                 if ((p = strrchr(target, '/')) == NULL)
 195                         p = target;
 196                 else
 197                         ++p;
 198                 if (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 }