hlink.c

   1 /*
   2    Copyright (C) Andrew Tridgell 1996
   3    Copyright (C) Paul Mackerras 1996
   4    Copyright (C) 2002 by Martin Pool <mbp@samba.org>
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 #include "rsync.h"
  22
  23 extern int dry_run;
  24 extern int verbose;
  25
  26 #if SUPPORT_HARD_LINKS
  27 static int hlink_compare(struct file_struct *f1, struct file_struct *f2)
  28 {
  29         if (!S_ISREG(f1->mode) && !S_ISREG(f2->mode))
  30                 return 0;
  31         if (!S_ISREG(f1->mode))
  32                 return -1;
  33         if (!S_ISREG(f2->mode))
  34                 return 1;
  35
  36         if (f1->dev != f2->dev)
  37                 return (int) (f1->dev > f2->dev ? 1 : -1);
  38
  39         if (f1->inode != f2->inode)
  40                 return (int) (f1->inode > f2->inode ? 1 : -1);
  41
  42         return file_compare(&f1, &f2);
  43 }
  44
  45
  46 static struct file_struct *hlink_list;
  47 static int hlink_count;
  48 #endif
  49
  50 void init_hard_links(struct file_list *flist)
  51 {
  52 #if SUPPORT_HARD_LINKS
  53         int i;
  54         if (flist->count < 2)
  55                 return;
  56
  57         if (hlink_list)
  58                 free(hlink_list);
  59
  60         if (!(hlink_list =
  61               (struct file_struct *) malloc(sizeof(hlink_list[0]) *
  62                                             flist->count)))
  63                 out_of_memory("init_hard_links");
  64
  65         for (i = 0; i < flist->count; i++)
  66                 memcpy(&hlink_list[i], flist->files[i],
  67                        sizeof(hlink_list[0]));
  68
  69         qsort(hlink_list, flist->count,
  70               sizeof(hlink_list[0]), (int (*)()) hlink_compare);
  71
  72         hlink_count = flist->count;
  73 #endif
  74 }
  75
  76 /* check if a file should be skipped because it is the same as an
  77    earlier hard link */
  78 int check_hard_link(struct file_struct *file)
  79 {
  80 #if SUPPORT_HARD_LINKS
  81         int low = 0, high = hlink_count - 1;
  82         int ret = 0;
  83
  84         if (!hlink_list || !S_ISREG(file->mode))
  85                 return 0;
  86
  87         while (low != high) {
  88                 int mid = (low + high) / 2;
  89                 ret = hlink_compare(&hlink_list[mid], file);
  90                 if (ret == 0) {
  91                         low = mid;
  92                         break;
  93                 }
  94                 if (ret > 0)
  95                         high = mid;
  96                 else
  97                         low = mid + 1;
  98         }
  99
 100         /* XXX: To me this looks kind of dodgy -- why do we use [low]
 101          * here and [low-1] below? -- mbp */
 102         if (hlink_compare(&hlink_list[low], file) != 0)
 103                 return 0;
 104
 105         if (low > 0 &&
 106             S_ISREG(hlink_list[low - 1].mode) &&
 107             file->dev == hlink_list[low - 1].dev &&
 108             file->inode == hlink_list[low - 1].inode) {
 109                 if (verbose >= 2) {
 110                         rprintf(FINFO, "check_hard_link: \"%s\" is a hard link to file %d, \"%s\"\n",
 111                                 f_name(file), low-1, f_name(&hlink_list[low-1]));
 112                 }
 113                 return 1;
 114         }
 115 #endif
 116
 117         return 0;
 118 }
 119
 120
 121 #if SUPPORT_HARD_LINKS
 122 static void hard_link_one(int i)
 123 {
 124         STRUCT_STAT st1, st2;
 125
 126         if (link_stat(f_name(&hlink_list[i - 1]), &st1) != 0)
 127                 return;
 128
 129         if (link_stat(f_name(&hlink_list[i]), &st2) != 0) {
 130                 if (do_link
 131                     (f_name(&hlink_list[i - 1]),
 132                      f_name(&hlink_list[i])) != 0) {
 133                         if (verbose > 0)
 134                                 rprintf(FINFO, "link %s => %s : %s\n",
 135                                         f_name(&hlink_list[i]),
 136                                         f_name(&hlink_list[i - 1]),
 137                                         strerror(errno));
 138                         return;
 139                 }
 140         } else {
 141                 if (st2.st_dev == st1.st_dev && st2.st_ino == st1.st_ino)
 142                         return;
 143
 144                 if (robust_unlink(f_name(&hlink_list[i])) != 0 ||
 145                     do_link(f_name(&hlink_list[i - 1]),
 146                             f_name(&hlink_list[i])) != 0) {
 147                         if (verbose > 0)
 148                                 rprintf(FINFO, "link %s => %s : %s\n",
 149                                         f_name(&hlink_list[i]),
 150                                         f_name(&hlink_list[i - 1]),
 151                                         strerror(errno));
 152                         return;
 153                 }
 154         }
 155         if (verbose > 0)
 156                 rprintf(FINFO, "%s => %s\n",
 157                         f_name(&hlink_list[i]),
 158                         f_name(&hlink_list[i - 1]));
 159 }
 160 #endif
 161
 162
 163
 164 /**
 165  * Create any hard links in the global hlink_list.  They were put
 166  * there by running init_hard_links on the filelist.
 167  **/
 168 void do_hard_links(void)
 169 {
 170 #if SUPPORT_HARD_LINKS
 171         int i;
 172
 173         if (!hlink_list)
 174                 return;
 175
 176         for (i = 1; i < hlink_count; i++) {
 177                 if (S_ISREG(hlink_list[i].mode) &&
 178                     S_ISREG(hlink_list[i - 1].mode) &&
 179                     hlink_list[i].basename && hlink_list[i - 1].basename &&
 180                     hlink_list[i].dev == hlink_list[i - 1].dev &&
 181                     hlink_list[i].inode == hlink_list[i - 1].inode) {
 182                         hard_link_one(i);
 183                 }
 184         }
 185 #endif
 186 }