coreutils/ln.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini ln implementation for busybox
   4  *
   5  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   8  */
   9
  10 /* BB_AUDIT SUSv3 compliant */
  11 /* BB_AUDIT GNU options missing: -d, -F, -i, and -v. */
  12 /* http://www.opengroup.org/onlinepubs/007904975/utilities/ln.html */
  13
  14 #include "busybox.h"
  15
  16 #define LN_SYMLINK          1
  17 #define LN_FORCE            2
  18 #define LN_NODEREFERENCE    4
  19 #define LN_BACKUP           8
  20 #define LN_SUFFIX           16
  21
  22 int ln_main(int argc, char **argv)
  23 {
  24         int status = EXIT_SUCCESS;
  25         int flag;
  26         char *last;
  27         char *src_name;
  28         char *src;
  29         char *suffix = "~";
  30         struct stat statbuf;
  31         int (*link_func)(const char *, const char *);
  32
  33         flag = bb_getopt_ulflags(argc, argv, "sfnbS:", &suffix);
  34
  35         if (argc == optind) {
  36                 bb_show_usage();
  37         }
  38
  39         last = argv[argc - 1];
  40         argv += optind;
  41
  42         if (argc == optind + 1) {
  43                 *--argv = last;
  44                 last = bb_get_last_path_component(xstrdup(last));
  45         }
  46
  47         do {
  48                 src_name = NULL;
  49                 src = last;
  50
  51                 if (is_directory(src,
  52                                                  (flag & LN_NODEREFERENCE) ^ LN_NODEREFERENCE,
  53                                                  NULL)) {
  54                         src_name = xstrdup(*argv);
  55                         src = concat_path_file(src, bb_get_last_path_component(src_name));
  56                         free(src_name);
  57                         src_name = src;
  58                 }
  59                 if (!(flag & LN_SYMLINK) && stat(*argv, &statbuf)) {
  60                         bb_perror_msg("%s", *argv);
  61                         status = EXIT_FAILURE;
  62                         free(src_name);
  63                         continue;
  64                 }
  65
  66                 if (flag & LN_BACKUP) {
  67                                 char *backup;
  68                                 backup = xasprintf("%s%s", src, suffix);
  69                                 if (rename(src, backup) < 0 && errno != ENOENT) {
  70                                                 bb_perror_msg("%s", src);
  71                                                 status = EXIT_FAILURE;
  72                                                 free(backup);
  73                                                 continue;
  74                                 }
  75                                 free(backup);
  76                                 /*
  77                                  * When the source and dest are both hard links to the same
  78                                  * inode, a rename may succeed even though nothing happened.
  79                                  * Therefore, always unlink().
  80                                  */
  81                                 unlink(src);
  82                 } else if (flag & LN_FORCE) {
  83                         unlink(src);
  84                 }
  85
  86                 link_func = link;
  87                 if (flag & LN_SYMLINK) {
  88                         link_func = symlink;
  89                 }
  90
  91                 if (link_func(*argv, src) != 0) {
  92                         bb_perror_msg("%s", src);
  93                         status = EXIT_FAILURE;
  94                 }
  95
  96                 free(src_name);
  97
  98         } while ((++argv)[1]);
  99
 100         return status;
 101 }