hlink.c

   1 /*
   2  * Routines to support hard-linking.
   3  *
   4  * Copyright (C) 1996 Andrew Tridgell
   5  * Copyright (C) 1996 Paul Mackerras
   6  * Copyright (C) 2002 Martin Pool <mbp@samba.org>
   7  * Copyright (C) 2004-2007 Wayne Davison
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 3 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, visit the http://fsf.org website.
  21  */
  22
  23 #include "rsync.h"
  24
  25 extern int verbose;
  26 extern int dry_run;
  27 extern int list_only;
  28 extern int am_sender;
  29 extern int inc_recurse;
  30 extern int do_xfers;
  31 extern int link_dest;
  32 extern int preserve_acls;
  33 extern int make_backups;
  34 extern int protocol_version;
  35 extern int remove_source_files;
  36 extern int stdout_format_has_i;
  37 extern int maybe_ATTRS_REPORT;
  38 extern int unsort_ndx;
  39 extern char *basis_dir[];
  40 extern struct file_list *cur_flist;
  41
  42 #ifdef SUPPORT_HARD_LINKS
  43
  44 /* Starting with protocol 30, we use a simple hashtable on the sending side
  45  * for hashing the st_dev and st_ino info.  The receiving side gets told
  46  * (via flags and a "group index") which items are hard-linked together, so
  47  * we can avoid the pool of dev+inode data.  For incremental recursion mode,
  48  * the receiver will use a ndx hash to remember old pathnames. */
  49
  50 static struct hashtable *dev_tbl;
  51
  52 static struct hashtable *prior_hlinks;
  53
  54 static struct file_list *hlink_flist;
  55
  56 void init_hard_links(void)
  57 {
  58         if (am_sender || protocol_version < 30)
  59                 dev_tbl = hashtable_create(16, SIZEOF_INT64 == 8);
  60         else if (inc_recurse)
  61                 prior_hlinks = hashtable_create(1024, 0);
  62 }
  63
  64 struct ht_int64_node *idev_find(int64 dev, int64 ino)
  65 {
  66         static struct ht_int64_node *dev_node = NULL;
  67         struct hashtable *tbl;
  68
  69         if (!dev_node || dev_node->key != dev) {
  70                 /* We keep a separate hash table of inodes for every device. */
  71                 dev_node = hashtable_find(dev_tbl, dev, 1);
  72                 if (!(tbl = dev_node->data))
  73                         tbl = dev_node->data = hashtable_create(512, SIZEOF_INT64 == 8);
  74         } else
  75                 tbl = dev_node->data;
  76
  77         return hashtable_find(tbl, ino, 1);
  78 }
  79
  80 void idev_destroy(void)
  81 {
  82         int i;
  83
  84         for (i = 0; i < dev_tbl->size; i++) {
  85                 struct ht_int32_node *node = HT_NODE(dev_tbl, dev_tbl->nodes, i);
  86                 if (node->data)
  87                         hashtable_destroy(node->data);
  88         }
  89
  90         hashtable_destroy(dev_tbl);
  91 }
  92
  93 static int hlink_compare_gnum(int *int1, int *int2)
  94 {
  95         struct file_struct *f1 = hlink_flist->sorted[*int1];
  96         struct file_struct *f2 = hlink_flist->sorted[*int2];
  97         int32 gnum1 = F_HL_GNUM(f1);
  98         int32 gnum2 = F_HL_GNUM(f2);
  99
 100         if (gnum1 != gnum2)
 101                 return gnum1 > gnum2 ? 1 : -1;
 102
 103         return *int1 > *int2 ? 1 : -1;
 104 }
 105
 106 static void match_gnums(int32 *ndx_list, int ndx_count)
 107 {
 108         int32 from, prev;
 109         struct file_struct *file, *file_next;
 110         struct ht_int32_node *node = NULL;
 111         int32 gnum, gnum_next;
 112
 113         qsort(ndx_list, ndx_count, sizeof ndx_list[0],
 114              (int (*)()) hlink_compare_gnum);
 115
 116         for (from = 0; from < ndx_count; from++) {
 117                 file = hlink_flist->sorted[ndx_list[from]];
 118                 gnum = F_HL_GNUM(file);
 119                 if (inc_recurse) {
 120                         node = hashtable_find(prior_hlinks, gnum, 1);
 121                         if (!node->data) {
 122                                 node->data = new_array0(char, 5);
 123                                 assert(gnum >= hlink_flist->ndx_start);
 124                                 file->flags |= FLAG_HLINK_FIRST;
 125                                 prev = -1;
 126                         } else if (CVAL(node->data, 0) == 0) {
 127                                 struct file_list *flist;
 128                                 struct file_struct *fp;
 129                                 prev = IVAL(node->data, 1);
 130                                 flist = flist_for_ndx(prev);
 131                                 assert(flist != NULL);
 132                                 fp = flist->files[prev - flist->ndx_start];
 133                                 fp->flags &= ~FLAG_HLINK_LAST;
 134                         } else
 135                                 prev = -1;
 136                 } else {
 137                         file->flags |= FLAG_HLINK_FIRST;
 138                         prev = -1;
 139                 }
 140                 for ( ; from < ndx_count-1; file = file_next, gnum = gnum_next, from++) { /*SHARED ITERATOR*/
 141                         file_next = hlink_flist->sorted[ndx_list[from+1]];
 142                         gnum_next = F_HL_GNUM(file_next);
 143                         if (gnum != gnum_next)
 144                                 break;
 145                         F_HL_PREV(file) = prev;
 146                         /* The linked list uses over-the-wire ndx values. */
 147                         if (unsort_ndx)
 148                                 prev = F_NDX(file);
 149                         else
 150                                 prev = ndx_list[from] + hlink_flist->ndx_start;
 151                 }
 152                 if (prev < 0 && !inc_recurse) {
 153                         /* Disable hard-link bit and set DONE so that
 154                          * HLINK_BUMP()-dependent values are unaffected. */
 155                         file->flags &= ~(FLAG_HLINKED | FLAG_HLINK_FIRST);
 156                         file->flags |= FLAG_HLINK_DONE;
 157                         continue;
 158                 }
 159
 160                 file->flags |= FLAG_HLINK_LAST;
 161                 F_HL_PREV(file) = prev;
 162                 if (inc_recurse && CVAL(node->data, 0) == 0) {
 163                         if (unsort_ndx)
 164                                 prev = F_NDX(file);
 165                         else
 166                                 prev = ndx_list[from] + hlink_flist->ndx_start;
 167                         SIVAL(node->data, 1, prev);
 168                 }
 169         }
 170 }
 171
 172 /* Analyze the hard-links in the file-list by creating a list of all the
 173  * items that have hlink data, sorting them, and matching up identical
 174  * values into clusters.  These will be a single linked list from last
 175  * to first when we're done. */
 176 void match_hard_links(struct file_list *flist)
 177 {
 178         if (!list_only) {
 179                 int i, ndx_count = 0;
 180                 int32 *ndx_list;
 181
 182                 if (!(ndx_list = new_array(int32, flist->used)))
 183                         out_of_memory("match_hard_links");
 184
 185                 for (i = 0; i < flist->used; i++) {
 186                         if (F_IS_HLINKED(flist->sorted[i]))
 187                                 ndx_list[ndx_count++] = i;
 188                 }
 189
 190                 hlink_flist = flist;
 191
 192                 if (ndx_count)
 193                         match_gnums(ndx_list, ndx_count);
 194
 195                 free(ndx_list);
 196         }
 197         if (protocol_version < 30)
 198                 idev_destroy();
 199 }
 200
 201 static int maybe_hard_link(struct file_struct *file, int ndx,
 202                            const char *fname, int statret, stat_x *sxp,
 203                            const char *oldname, STRUCT_STAT *old_stp,
 204                            const char *realname, int itemizing, enum logcode code)
 205 {
 206         if (statret == 0) {
 207                 if (sxp->st.st_dev == old_stp->st_dev
 208                  && sxp->st.st_ino == old_stp->st_ino) {
 209                         if (itemizing) {
 210                                 itemize(fname, file, ndx, statret, sxp,
 211                                         ITEM_LOCAL_CHANGE | ITEM_XNAME_FOLLOWS,
 212                                         0, "");
 213                         }
 214                         if (verbose > 1 && maybe_ATTRS_REPORT)
 215                                 rprintf(FCLIENT, "%s is uptodate\n", fname);
 216                         file->flags |= FLAG_HLINK_DONE;
 217                         return 0;
 218                 }
 219                 if (make_backups > 0) {
 220                         if (!make_backup(fname))
 221                                 return -1;
 222                 } else if (robust_unlink(fname)) {
 223                         rsyserr(FERROR_XFER, errno, "unlink %s failed",
 224                                 full_fname(fname));
 225                         return -1;
 226                 }
 227         }
 228
 229         if (hard_link_one(file, fname, oldname, 0)) {
 230                 if (itemizing) {
 231                         itemize(fname, file, ndx, statret, sxp,
 232                                 ITEM_LOCAL_CHANGE | ITEM_XNAME_FOLLOWS, 0,
 233                                 realname);
 234                 }
 235                 if (code != FNONE && verbose)
 236                         rprintf(code, "%s => %s\n", fname, realname);
 237                 return 0;
 238         }
 239         return -1;
 240 }
 241
 242 /* Figure out if a prior entry is still there or if we just have a
 243  * cached name for it.  Never called with a FLAG_HLINK_FIRST entry. */
 244 static char *check_prior(int prev_ndx, int gnum, struct file_list **flist_p)
 245 {
 246         struct file_list *flist = flist_for_ndx(prev_ndx);
 247         struct ht_int32_node *node;
 248
 249         if (flist) {
 250                 *flist_p = flist;
 251                 return NULL;
 252         }
 253
 254         node = hashtable_find(prior_hlinks, gnum, 0);
 255         assert(node != NULL && node->data);
 256         assert(CVAL(node->data, 0) != 0);
 257         return node->data;
 258 }
 259
 260 /* Only called if FLAG_HLINKED is set and FLAG_HLINK_FIRST is not.  Returns:
 261  * 0 = process the file, 1 = skip the file, -1 = error occurred. */
 262 int hard_link_check(struct file_struct *file, int ndx, const char *fname,
 263                     int statret, stat_x *sxp, int itemizing,
 264                     enum logcode code)
 265 {
 266         STRUCT_STAT prev_st;
 267         char namebuf[MAXPATHLEN], altbuf[MAXPATHLEN];
 268         char *realname, *prev_name;
 269         struct file_list *flist;
 270         int gnum = inc_recurse ? F_HL_GNUM(file) : -1;
 271         int prev_ndx = F_HL_PREV(file);
 272
 273         prev_name = realname = check_prior(prev_ndx, gnum, &flist);
 274
 275         if (!prev_name) {
 276                 struct file_struct *prev_file = flist->files[prev_ndx - flist->ndx_start];
 277
 278                 /* Is the previous link not complete yet? */
 279                 if (!(prev_file->flags & FLAG_HLINK_DONE)) {
 280                         /* Is the previous link being transferred? */
 281                         if (prev_file->flags & FLAG_FILE_SENT) {
 282                                 /* Add ourselves to the list of files that will
 283                                  * be updated when the transfer completes, and
 284                                  * mark ourself as waiting for the transfer. */
 285                                 F_HL_PREV(file) = F_HL_PREV(prev_file);
 286                                 F_HL_PREV(prev_file) = ndx;
 287                                 file->flags |= FLAG_FILE_SENT;
 288                                 cur_flist->in_progress++;
 289                                 return 1;
 290                         }
 291                         return 0;
 292                 }
 293
 294                 /* There is a finished file to link with! */
 295                 if (!(prev_file->flags & FLAG_HLINK_FIRST)) {
 296                         /* The previous previous is FIRST when prev is not. */
 297                         prev_ndx = F_HL_PREV(prev_file);
 298                         prev_name = realname = check_prior(prev_ndx, gnum, &flist);
 299                         /* Update our previous pointer to point to the FIRST. */
 300                         F_HL_PREV(file) = prev_ndx;
 301                 }
 302
 303                 if (!prev_name) {
 304                         int alt_dest;
 305
 306                         prev_file = flist->files[prev_ndx - flist->ndx_start];
 307                         /* F_HL_PREV() is alt_dest value when DONE && FIRST. */
 308                         alt_dest = F_HL_PREV(prev_file);
 309
 310                         if (alt_dest >= 0 && dry_run) {
 311                                 pathjoin(namebuf, MAXPATHLEN, basis_dir[alt_dest],
 312                                          f_name(prev_file, NULL));
 313                                 prev_name = namebuf;
 314                                 realname = f_name(prev_file, altbuf);
 315                         } else {
 316                                 prev_name = f_name(prev_file, namebuf);
 317                                 realname = prev_name;
 318                         }
 319                 }
 320         }
 321
 322         if (link_stat(prev_name, &prev_st, 0) < 0) {
 323                 rsyserr(FERROR_XFER, errno, "stat %s failed",
 324                         full_fname(prev_name));
 325                 return -1;
 326         }
 327
 328         if (statret < 0 && basis_dir[0] != NULL) {
 329                 /* If we match an alt-dest item, we don't output this as a change. */
 330                 char cmpbuf[MAXPATHLEN];
 331                 stat_x alt_sx;
 332                 int j = 0;
 333 #ifdef SUPPORT_ACLS
 334                 alt_sx.acc_acl = alt_sx.def_acl = NULL;
 335 #endif
 336                 do {
 337                         pathjoin(cmpbuf, MAXPATHLEN, basis_dir[j], fname);
 338                         if (link_stat(cmpbuf, &alt_sx.st, 0) < 0)
 339                                 continue;
 340                         if (link_dest) {
 341                                 if (prev_st.st_dev != alt_sx.st.st_dev
 342                                  || prev_st.st_ino != alt_sx.st.st_ino)
 343                                         continue;
 344                                 statret = 1;
 345                                 if (stdout_format_has_i == 0
 346                                  || (verbose < 2 && stdout_format_has_i < 2)) {
 347                                         itemizing = 0;
 348                                         code = FNONE;
 349                                         if (verbose > 1 && maybe_ATTRS_REPORT)
 350                                                 rprintf(FCLIENT, "%s is uptodate\n", fname);
 351                                 }
 352                                 break;
 353                         }
 354                         if (!unchanged_file(cmpbuf, file, &alt_sx.st))
 355                                 continue;
 356                         statret = 1;
 357                         if (unchanged_attrs(cmpbuf, file, &alt_sx))
 358                                 break;
 359                 } while (basis_dir[++j] != NULL);
 360                 if (statret == 1) {
 361                         sxp->st = alt_sx.st;
 362 #ifdef SUPPORT_ACLS
 363                         if (preserve_acls && !S_ISLNK(file->mode)) {
 364                                 if (!ACL_READY(*sxp))
 365                                         get_acl(cmpbuf, sxp);
 366                                 else {
 367                                         sxp->acc_acl = alt_sx.acc_acl;
 368                                         sxp->def_acl = alt_sx.def_acl;
 369                                 }
 370                         }
 371 #endif
 372                 }
 373 #ifdef SUPPORT_ACLS
 374                 else if (preserve_acls)
 375                         free_acl(&alt_sx);
 376 #endif
 377         }
 378
 379         if (maybe_hard_link(file, ndx, fname, statret, sxp, prev_name, &prev_st,
 380                             realname, itemizing, code) < 0)
 381                 return -1;
 382
 383         if (remove_source_files == 1 && do_xfers)
 384                 send_msg_int(MSG_SUCCESS, ndx);
 385
 386         return 1;
 387 }
 388
 389 int hard_link_one(struct file_struct *file, const char *fname,
 390                   const char *oldname, int terse)
 391 {
 392         if (do_link(oldname, fname) < 0) {
 393                 enum logcode code;
 394                 if (terse) {
 395                         if (!verbose)
 396                                 return 0;
 397                         code = FINFO;
 398                 } else
 399                         code = FERROR_XFER;
 400                 rsyserr(code, errno, "link %s => %s failed",
 401                         full_fname(fname), oldname);
 402                 return 0;
 403         }
 404
 405         file->flags |= FLAG_HLINK_DONE;
 406
 407         return 1;
 408 }
 409
 410 void finish_hard_link(struct file_struct *file, const char *fname, int fin_ndx,
 411                       STRUCT_STAT *stp, int itemizing, enum logcode code,
 412                       int alt_dest)
 413 {
 414         stat_x prev_sx;
 415         STRUCT_STAT st;
 416         char alt_name[MAXPATHLEN], *prev_name;
 417         const char *our_name;
 418         struct file_list *flist;
 419         int prev_statret, ndx, prev_ndx = F_HL_PREV(file);
 420
 421         if (stp == NULL && prev_ndx >= 0) {
 422                 if (link_stat(fname, &st, 0) < 0) {
 423                         rsyserr(FERROR_XFER, errno, "stat %s failed",
 424                                 full_fname(fname));
 425                         return;
 426                 }
 427                 stp = &st;
 428         }
 429
 430         /* FIRST combined with DONE means we were the first to get done. */
 431         file->flags |= FLAG_HLINK_FIRST | FLAG_HLINK_DONE;
 432         F_HL_PREV(file) = alt_dest;
 433         if (alt_dest >= 0 && dry_run) {
 434                 pathjoin(alt_name, MAXPATHLEN, basis_dir[alt_dest],
 435                          f_name(file, NULL));
 436                 our_name = alt_name;
 437         } else
 438                 our_name = fname;
 439
 440 #ifdef SUPPORT_ACLS
 441         prev_sx.acc_acl = prev_sx.def_acl = NULL;
 442 #endif
 443
 444         while ((ndx = prev_ndx) >= 0) {
 445                 int val;
 446                 flist = flist_for_ndx(ndx);
 447                 assert(flist != NULL);
 448                 file = flist->files[ndx - flist->ndx_start];
 449                 file->flags = (file->flags & ~FLAG_HLINK_FIRST) | FLAG_HLINK_DONE;
 450                 prev_ndx = F_HL_PREV(file);
 451                 F_HL_PREV(file) = fin_ndx;
 452                 prev_name = f_name(file, NULL);
 453                 prev_statret = link_stat(prev_name, &prev_sx.st, 0);
 454                 val = maybe_hard_link(file, ndx, prev_name, prev_statret, &prev_sx,
 455                                       our_name, stp, fname, itemizing, code);
 456                 flist->in_progress--;
 457 #ifdef SUPPORT_ACLS
 458                 if (preserve_acls)
 459                         free_acl(&prev_sx);
 460 #endif
 461                 if (val < 0)
 462                         continue;
 463                 if (remove_source_files == 1 && do_xfers)
 464                         send_msg_int(MSG_SUCCESS, ndx);
 465         }
 466
 467         if (inc_recurse) {
 468                 int gnum = F_HL_GNUM(file);
 469                 struct ht_int32_node *node = hashtable_find(prior_hlinks, gnum, 0);
 470                 assert(node != NULL && node->data != NULL);
 471                 assert(CVAL(node->data, 0) == 0);
 472                 free(node->data);
 473                 if (!(node->data = strdup(our_name)))
 474                         out_of_memory("finish_hard_link");
 475         }
 476 }
 477 #endif