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) 2004-2008 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 #include "ifuncs.h"
  25
  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[MAX_BASIS_DIRS+1];
  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                         if (DEBUG_GTE(HLINK, 3)) {
  75                                 rprintf(FINFO,
  76                                     "[%s] created hashtable for dev %s\n",
  77                                     who_am_i(), big_num(dev));
  78                         }
  79                 }
  80         } else
  81                 tbl = dev_node->data;
  82
  83         return hashtable_find(tbl, ino, 1);
  84 }
  85
  86 void idev_destroy(void)
  87 {
  88         int i;
  89
  90         for (i = 0; i < dev_tbl->size; i++) {
  91                 struct ht_int32_node *node = HT_NODE(dev_tbl, dev_tbl->nodes, i);
  92                 if (node->data)
  93                         hashtable_destroy(node->data);
  94         }
  95
  96         hashtable_destroy(dev_tbl);
  97 }
  98
  99 static int hlink_compare_gnum(int *int1, int *int2)
 100 {
 101         struct file_struct *f1 = hlink_flist->sorted[*int1];
 102         struct file_struct *f2 = hlink_flist->sorted[*int2];
 103         int32 gnum1 = F_HL_GNUM(f1);
 104         int32 gnum2 = F_HL_GNUM(f2);
 105
 106         if (gnum1 != gnum2)
 107                 return gnum1 > gnum2 ? 1 : -1;
 108
 109         return *int1 > *int2 ? 1 : -1;
 110 }
 111
 112 static void match_gnums(int32 *ndx_list, int ndx_count)
 113 {
 114         int32 from, prev;
 115         struct file_struct *file, *file_next;
 116         struct ht_int32_node *node = NULL;
 117         int32 gnum, gnum_next;
 118
 119         qsort(ndx_list, ndx_count, sizeof ndx_list[0],
 120              (int (*)()) hlink_compare_gnum);
 121
 122         for (from = 0; from < ndx_count; from++) {
 123                 file = hlink_flist->sorted[ndx_list[from]];
 124                 gnum = F_HL_GNUM(file);
 125                 if (inc_recurse) {
 126                         node = hashtable_find(prior_hlinks, gnum, 1);
 127                         if (!node->data) {
 128                                 if (!(node->data = new_array0(char, 5)))
 129                                         out_of_memory("match_gnums");
 130                                 assert(gnum >= hlink_flist->ndx_start);
 131                                 file->flags |= FLAG_HLINK_FIRST;
 132                                 prev = -1;
 133                         } else if (CVAL(node->data, 0) == 0) {
 134                                 struct file_list *flist;
 135                                 prev = IVAL(node->data, 1);
 136                                 flist = flist_for_ndx(prev, NULL);
 137                                 if (flist)
 138                                         flist->files[prev - flist->ndx_start]->flags &= ~FLAG_HLINK_LAST;
 139                                 else {
 140                                         /* We skipped all prior files in this
 141                                          * group, so mark this as a "first". */
 142                                         file->flags |= FLAG_HLINK_FIRST;
 143                                         prev = -1;
 144                                 }
 145                         } else
 146                                 prev = -1;
 147                 } else {
 148                         file->flags |= FLAG_HLINK_FIRST;
 149                         prev = -1;
 150                 }
 151                 for ( ; from < ndx_count-1; file = file_next, gnum = gnum_next, from++) { /*SHARED ITERATOR*/
 152                         file_next = hlink_flist->sorted[ndx_list[from+1]];
 153                         gnum_next = F_HL_GNUM(file_next);
 154                         if (gnum != gnum_next)
 155                                 break;
 156                         F_HL_PREV(file) = prev;
 157                         /* The linked list uses over-the-wire ndx values. */
 158                         if (unsort_ndx)
 159                                 prev = F_NDX(file);
 160                         else
 161                                 prev = ndx_list[from] + hlink_flist->ndx_start;
 162                 }
 163                 if (prev < 0 && !inc_recurse) {
 164                         /* Disable hard-link bit and set DONE so that
 165                          * HLINK_BUMP()-dependent values are unaffected. */
 166                         file->flags &= ~(FLAG_HLINKED | FLAG_HLINK_FIRST);
 167                         file->flags |= FLAG_HLINK_DONE;
 168                         continue;
 169                 }
 170
 171                 file->flags |= FLAG_HLINK_LAST;
 172                 F_HL_PREV(file) = prev;
 173                 if (inc_recurse && CVAL(node->data, 0) == 0) {
 174                         if (unsort_ndx)
 175                                 prev = F_NDX(file);
 176                         else
 177                                 prev = ndx_list[from] + hlink_flist->ndx_start;
 178                         SIVAL(node->data, 1, prev);
 179                 }
 180         }
 181 }
 182
 183 /* Analyze the hard-links in the file-list by creating a list of all the
 184  * items that have hlink data, sorting them, and matching up identical
 185  * values into clusters.  These will be a single linked list from last
 186  * to first when we're done. */
 187 void match_hard_links(struct file_list *flist)
 188 {
 189         if (!list_only && flist->used) {
 190                 int i, ndx_count = 0;
 191                 int32 *ndx_list;
 192
 193                 if (!(ndx_list = new_array(int32, flist->used)))
 194                         out_of_memory("match_hard_links");
 195
 196                 for (i = 0; i < flist->used; i++) {
 197                         if (F_IS_HLINKED(flist->sorted[i]))
 198                                 ndx_list[ndx_count++] = i;
 199                 }
 200
 201                 hlink_flist = flist;
 202
 203                 if (ndx_count)
 204                         match_gnums(ndx_list, ndx_count);
 205
 206                 free(ndx_list);
 207         }
 208         if (protocol_version < 30)
 209                 idev_destroy();
 210 }
 211
 212 static int maybe_hard_link(struct file_struct *file, int ndx,
 213                            const char *fname, int statret, stat_x *sxp,
 214                            const char *oldname, STRUCT_STAT *old_stp,
 215                            const char *realname, int itemizing, enum logcode code)
 216 {
 217         if (statret == 0) {
 218                 if (sxp->st.st_dev == old_stp->st_dev
 219                  && sxp->st.st_ino == old_stp->st_ino) {
 220                         if (itemizing) {
 221                                 itemize(fname, file, ndx, statret, sxp,
 222                                         ITEM_LOCAL_CHANGE | ITEM_XNAME_FOLLOWS,
 223                                         0, "");
 224                         }
 225                         if (INFO_GTE(NAME, 2) && maybe_ATTRS_REPORT)
 226                                 rprintf(FCLIENT, "%s is uptodate\n", fname);
 227                         file->flags |= FLAG_HLINK_DONE;
 228                         return 0;
 229                 }
 230                 if (make_backups > 0) {
 231                         if (!make_backup(fname))
 232                                 return -1;
 233                 } else if (robust_unlink(fname)) {
 234                         rsyserr(FERROR_XFER, errno, "unlink %s failed",
 235                                 full_fname(fname));
 236                         return -1;
 237                 }
 238         }
 239
 240         if (hard_link_one(file, fname, oldname, 0)) {
 241                 if (itemizing) {
 242                         itemize(fname, file, ndx, statret, sxp,
 243                                 ITEM_LOCAL_CHANGE | ITEM_XNAME_FOLLOWS, 0,
 244                                 realname);
 245                 }
 246                 if (code != FNONE && INFO_GTE(NAME, 1))
 247                         rprintf(code, "%s => %s\n", fname, realname);
 248                 return 0;
 249         }
 250         return -1;
 251 }
 252
 253 /* Figure out if a prior entry is still there or if we just have a
 254  * cached name for it. */
 255 static char *check_prior(struct file_struct *file, int gnum,
 256                          int *prev_ndx_p, struct file_list **flist_p)
 257 {
 258         struct file_struct *fp;
 259         struct ht_int32_node *node;
 260         int prev_ndx = F_HL_PREV(file);
 261
 262         while (1) {
 263                 struct file_list *flist;
 264                 if (prev_ndx < 0
 265                  || (flist = flist_for_ndx(prev_ndx, NULL)) == NULL)
 266                         break;
 267                 fp = flist->files[prev_ndx - flist->ndx_start];
 268                 if (!(fp->flags & FLAG_SKIP_HLINK)) {
 269                         *prev_ndx_p = prev_ndx;
 270                         *flist_p = flist;
 271                         return NULL;
 272                 }
 273                 F_HL_PREV(file) = prev_ndx = F_HL_PREV(fp);
 274         }
 275
 276         if (inc_recurse
 277          && (node = hashtable_find(prior_hlinks, gnum, 0)) != NULL) {
 278                 assert(node->data != NULL);
 279                 if (CVAL(node->data, 0) != 0) {
 280                         *prev_ndx_p = -1;
 281                         *flist_p = NULL;
 282                         return node->data;
 283                 }
 284                 /* The prior file must have been skipped. */
 285                 F_HL_PREV(file) = -1;
 286         }
 287
 288         *prev_ndx_p = -1;
 289         *flist_p = NULL;
 290         return NULL;
 291 }
 292
 293 /* Only called if FLAG_HLINKED is set and FLAG_HLINK_FIRST is not.  Returns:
 294  * 0 = process the file, 1 = skip the file, -1 = error occurred. */
 295 int hard_link_check(struct file_struct *file, int ndx, const char *fname,
 296                     int statret, stat_x *sxp, int itemizing,
 297                     enum logcode code)
 298 {
 299         STRUCT_STAT prev_st;
 300         char namebuf[MAXPATHLEN], altbuf[MAXPATHLEN];
 301         char *realname, *prev_name;
 302         struct file_list *flist;
 303         int gnum = inc_recurse ? F_HL_GNUM(file) : -1;
 304         int prev_ndx;
 305
 306         prev_name = realname = check_prior(file, gnum, &prev_ndx, &flist);
 307
 308         if (!prev_name) {
 309                 struct file_struct *prev_file;
 310
 311                 if (!flist) {
 312                         /* The previous file was skipped, so this one is
 313                          * treated as if it were the first in its group. */
 314                         if (DEBUG_GTE(HLINK, 2)) {
 315                                 rprintf(FINFO, "hlink for %d (%s,%d): virtual first\n",
 316                                         ndx, f_name(file, NULL), gnum);
 317                         }
 318                         return 0;
 319                 }
 320
 321                 prev_file = flist->files[prev_ndx - flist->ndx_start];
 322
 323                 /* Is the previous link not complete yet? */
 324                 if (!(prev_file->flags & FLAG_HLINK_DONE)) {
 325                         /* Is the previous link being transferred? */
 326                         if (prev_file->flags & FLAG_FILE_SENT) {
 327                                 /* Add ourselves to the list of files that will
 328                                  * be updated when the transfer completes, and
 329                                  * mark ourself as waiting for the transfer. */
 330                                 F_HL_PREV(file) = F_HL_PREV(prev_file);
 331                                 F_HL_PREV(prev_file) = ndx;
 332                                 file->flags |= FLAG_FILE_SENT;
 333                                 cur_flist->in_progress++;
 334                                 if (DEBUG_GTE(HLINK, 2)) {
 335                                         rprintf(FINFO, "hlink for %d (%s,%d): waiting for %d\n",
 336                                                 ndx, f_name(file, NULL), gnum, F_HL_PREV(file));
 337                                 }
 338                                 return 1;
 339                         }
 340                         if (DEBUG_GTE(HLINK, 2)) {
 341                                 rprintf(FINFO, "hlink for %d (%s,%d): looking for a leader\n",
 342                                         ndx, f_name(file, NULL), gnum);
 343                         }
 344                         return 0;
 345                 }
 346
 347                 /* There is a finished file to link with! */
 348                 if (!(prev_file->flags & FLAG_HLINK_FIRST)) {
 349                         /* The previous previous is FIRST when prev is not. */
 350                         prev_name = realname = check_prior(prev_file, gnum, &prev_ndx, &flist);
 351                         /* Update our previous pointer to point to the FIRST. */
 352                         F_HL_PREV(file) = prev_ndx;
 353                 }
 354
 355                 if (!prev_name) {
 356                         int alt_dest;
 357
 358                         assert(flist != NULL);
 359                         prev_file = flist->files[prev_ndx - flist->ndx_start];
 360                         /* F_HL_PREV() is alt_dest value when DONE && FIRST. */
 361                         alt_dest = F_HL_PREV(prev_file);
 362                         if (DEBUG_GTE(HLINK, 2)) {
 363                                 rprintf(FINFO, "hlink for %d (%s,%d): found flist match (alt %d)\n",
 364                                         ndx, f_name(file, NULL), gnum, alt_dest);
 365                         }
 366
 367                         if (alt_dest >= 0 && dry_run) {
 368                                 pathjoin(namebuf, MAXPATHLEN, basis_dir[alt_dest],
 369                                          f_name(prev_file, NULL));
 370                                 prev_name = namebuf;
 371                                 realname = f_name(prev_file, altbuf);
 372                         } else {
 373                                 prev_name = f_name(prev_file, namebuf);
 374                                 realname = prev_name;
 375                         }
 376                 }
 377         }
 378
 379         if (DEBUG_GTE(HLINK, 2)) {
 380                 rprintf(FINFO, "hlink for %d (%s,%d): leader is %d (%s)\n",
 381                         ndx, f_name(file, NULL), gnum, prev_ndx, prev_name);
 382         }
 383
 384         if (link_stat(prev_name, &prev_st, 0) < 0) {
 385                 rsyserr(FERROR_XFER, errno, "stat %s failed",
 386                         full_fname(prev_name));
 387                 return -1;
 388         }
 389
 390         if (statret < 0 && basis_dir[0] != NULL) {
 391                 /* If we match an alt-dest item, we don't output this as a change. */
 392                 char cmpbuf[MAXPATHLEN];
 393                 stat_x alt_sx;
 394                 int j = 0;
 395 #ifdef SUPPORT_ACLS
 396                 alt_sx.acc_acl = alt_sx.def_acl = NULL;
 397 #endif
 398                 do {
 399                         pathjoin(cmpbuf, MAXPATHLEN, basis_dir[j], fname);
 400                         if (link_stat(cmpbuf, &alt_sx.st, 0) < 0)
 401                                 continue;
 402                         if (link_dest) {
 403                                 if (prev_st.st_dev != alt_sx.st.st_dev
 404                                  || prev_st.st_ino != alt_sx.st.st_ino)
 405                                         continue;
 406                                 statret = 1;
 407                                 if (stdout_format_has_i == 0
 408                                  || (!INFO_GTE(NAME, 2) && stdout_format_has_i < 2)) {
 409                                         itemizing = 0;
 410                                         code = FNONE;
 411                                         if (INFO_GTE(NAME, 2) && maybe_ATTRS_REPORT)
 412                                                 rprintf(FCLIENT, "%s is uptodate\n", fname);
 413                                 }
 414                                 break;
 415                         }
 416                         if (!unchanged_file(cmpbuf, file, &alt_sx.st))
 417                                 continue;
 418                         statret = 1;
 419                         if (unchanged_attrs(cmpbuf, file, &alt_sx))
 420                                 break;
 421                 } while (basis_dir[++j] != NULL);
 422                 if (statret == 1) {
 423                         sxp->st = alt_sx.st;
 424 #ifdef SUPPORT_ACLS
 425                         if (preserve_acls && !S_ISLNK(file->mode)) {
 426                                 if (!ACL_READY(*sxp))
 427                                         get_acl(cmpbuf, sxp);
 428                                 else {
 429                                         sxp->acc_acl = alt_sx.acc_acl;
 430                                         sxp->def_acl = alt_sx.def_acl;
 431                                 }
 432                         }
 433 #endif
 434                 }
 435 #ifdef SUPPORT_ACLS
 436                 else if (preserve_acls)
 437                         free_acl(&alt_sx);
 438 #endif
 439         }
 440
 441         if (maybe_hard_link(file, ndx, fname, statret, sxp, prev_name, &prev_st,
 442                             realname, itemizing, code) < 0)
 443                 return -1;
 444
 445         if (remove_source_files == 1 && do_xfers)
 446                 send_msg_int(MSG_SUCCESS, ndx);
 447
 448         return 1;
 449 }
 450
 451 int hard_link_one(struct file_struct *file, const char *fname,
 452                   const char *oldname, int terse)
 453 {
 454         if (do_link(oldname, fname) < 0) {
 455                 enum logcode code;
 456                 if (terse) {
 457                         if (!INFO_GTE(NAME, 1))
 458                                 return 0;
 459                         code = FINFO;
 460                 } else
 461                         code = FERROR_XFER;
 462                 rsyserr(code, errno, "link %s => %s failed",
 463                         full_fname(fname), oldname);
 464                 return 0;
 465         }
 466
 467         file->flags |= FLAG_HLINK_DONE;
 468
 469         return 1;
 470 }
 471
 472 void finish_hard_link(struct file_struct *file, const char *fname, int fin_ndx,
 473                       STRUCT_STAT *stp, int itemizing, enum logcode code,
 474                       int alt_dest)
 475 {
 476         stat_x prev_sx;
 477         STRUCT_STAT st;
 478         char prev_name[MAXPATHLEN], alt_name[MAXPATHLEN];
 479         const char *our_name;
 480         struct file_list *flist;
 481         int prev_statret, ndx, prev_ndx = F_HL_PREV(file);
 482
 483         if (stp == NULL && prev_ndx >= 0) {
 484                 if (link_stat(fname, &st, 0) < 0) {
 485                         rsyserr(FERROR_XFER, errno, "stat %s failed",
 486                                 full_fname(fname));
 487                         return;
 488                 }
 489                 stp = &st;
 490         }
 491
 492         /* FIRST combined with DONE means we were the first to get done. */
 493         file->flags |= FLAG_HLINK_FIRST | FLAG_HLINK_DONE;
 494         F_HL_PREV(file) = alt_dest;
 495         if (alt_dest >= 0 && dry_run) {
 496                 pathjoin(alt_name, MAXPATHLEN, basis_dir[alt_dest],
 497                          f_name(file, NULL));
 498                 our_name = alt_name;
 499         } else
 500                 our_name = fname;
 501
 502 #ifdef SUPPORT_ACLS
 503         prev_sx.acc_acl = prev_sx.def_acl = NULL;
 504 #endif
 505
 506         while ((ndx = prev_ndx) >= 0) {
 507                 int val;
 508                 flist = flist_for_ndx(ndx, "finish_hard_link");
 509                 file = flist->files[ndx - flist->ndx_start];
 510                 file->flags = (file->flags & ~FLAG_HLINK_FIRST) | FLAG_HLINK_DONE;
 511                 prev_ndx = F_HL_PREV(file);
 512                 F_HL_PREV(file) = fin_ndx;
 513                 prev_statret = link_stat(f_name(file, prev_name), &prev_sx.st, 0);
 514                 val = maybe_hard_link(file, ndx, prev_name, prev_statret, &prev_sx,
 515                                       our_name, stp, fname, itemizing, code);
 516                 flist->in_progress--;
 517 #ifdef SUPPORT_ACLS
 518                 if (preserve_acls)
 519                         free_acl(&prev_sx);
 520 #endif
 521                 if (val < 0)
 522                         continue;
 523                 if (remove_source_files == 1 && do_xfers)
 524                         send_msg_int(MSG_SUCCESS, ndx);
 525         }
 526
 527         if (inc_recurse) {
 528                 int gnum = F_HL_GNUM(file);
 529                 struct ht_int32_node *node = hashtable_find(prior_hlinks, gnum, 0);
 530                 assert(node != NULL && node->data != NULL);
 531                 assert(CVAL(node->data, 0) == 0);
 532                 free(node->data);
 533                 if (!(node->data = strdup(our_name)))
 534                         out_of_memory("finish_hard_link");
 535         }
 536 }
 537
 538 int skip_hard_link(struct file_struct *file, struct file_list **flist_p)
 539 {
 540         struct file_list *flist;
 541         int prev_ndx;
 542
 543         file->flags |= FLAG_SKIP_HLINK;
 544         if (!(file->flags & FLAG_HLINK_LAST))
 545                 return -1;
 546
 547         check_prior(file, F_HL_GNUM(file), &prev_ndx, &flist);
 548         if (prev_ndx >= 0) {
 549                 file = flist->files[prev_ndx - flist->ndx_start];
 550                 if (file->flags & (FLAG_HLINK_DONE|FLAG_FILE_SENT))
 551                         return -1;
 552                 file->flags |= FLAG_HLINK_LAST;
 553                 *flist_p = flist;
 554         }
 555
 556         return prev_ndx;
 557 }
 558 #endif