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) 2004-2019 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 "inums.h"
  25 #include "ifuncs.h"
  26
  27 extern int dry_run;
  28 extern int list_only;
  29 extern int am_sender;
  30 extern int inc_recurse;
  31 extern int do_xfers;
  32 extern int link_dest;
  33 extern int preserve_acls;
  34 extern int preserve_xattrs;
  35 extern int protocol_version;
  36 extern int remove_source_files;
  37 extern int stdout_format_has_i;
  38 extern int maybe_ATTRS_REPORT;
  39 extern int unsort_ndx;
  40 extern char *basis_dir[MAX_BASIS_DIRS+1];
  41 extern struct file_list *cur_flist;
  42
  43 #ifdef SUPPORT_HARD_LINKS
  44
  45 /* Starting with protocol 30, we use a simple hashtable on the sending side
  46  * for hashing the st_dev and st_ino info.  The receiving side gets told
  47  * (via flags and a "group index") which items are hard-linked together, so
  48  * we can avoid the pool of dev+inode data.  For incremental recursion mode,
  49  * the receiver will use a ndx hash to remember old pathnames. */
  50
  51 static struct hashtable *dev_tbl;
  52
  53 static struct hashtable *prior_hlinks;
  54
  55 static struct file_list *hlink_flist;
  56
  57 void init_hard_links(void)
  58 {
  59         if (am_sender || protocol_version < 30)
  60                 dev_tbl = hashtable_create(16, 1);
  61         else if (inc_recurse)
  62                 prior_hlinks = hashtable_create(1024, 0);
  63 }
  64
  65 struct ht_int64_node *idev_find(int64 dev, int64 ino)
  66 {
  67         static struct ht_int64_node *dev_node = NULL;
  68         struct hashtable *tbl;
  69
  70         /* Note that some OSes have a dev == 0, so increment to avoid storing a 0. */
  71         if (!dev_node || dev_node->key != dev+1) {
  72                 /* We keep a separate hash table of inodes for every device. */
  73                 dev_node = hashtable_find(dev_tbl, dev+1, 1);
  74                 if (!(tbl = dev_node->data)) {
  75                         tbl = dev_node->data = hashtable_create(512, 1);
  76                         if (DEBUG_GTE(HLINK, 3)) {
  77                                 rprintf(FINFO,
  78                                     "[%s] created hashtable for dev %s\n",
  79                                     who_am_i(), big_num(dev));
  80                         }
  81                 }
  82         } else
  83                 tbl = dev_node->data;
  84
  85         return hashtable_find(tbl, ino, 1);
  86 }
  87
  88 void idev_destroy(void)
  89 {
  90         int i;
  91
  92         for (i = 0; i < dev_tbl->size; i++) {
  93                 struct ht_int32_node *node = HT_NODE(dev_tbl, dev_tbl->nodes, i);
  94                 if (node->data)
  95                         hashtable_destroy(node->data);
  96         }
  97
  98         hashtable_destroy(dev_tbl);
  99 }
 100
 101 static int hlink_compare_gnum(int *int1, int *int2)
 102 {
 103         struct file_struct *f1 = hlink_flist->sorted[*int1];
 104         struct file_struct *f2 = hlink_flist->sorted[*int2];
 105         int32 gnum1 = F_HL_GNUM(f1);
 106         int32 gnum2 = F_HL_GNUM(f2);
 107
 108         if (gnum1 != gnum2)
 109                 return gnum1 > gnum2 ? 1 : -1;
 110
 111         return *int1 > *int2 ? 1 : -1;
 112 }
 113
 114 static void match_gnums(int32 *ndx_list, int ndx_count)
 115 {
 116         int32 from, prev;
 117         struct file_struct *file, *file_next;
 118         struct ht_int32_node *node = NULL;
 119         int32 gnum, gnum_next;
 120
 121         qsort(ndx_list, ndx_count, sizeof ndx_list[0],
 122              (int (*)()) hlink_compare_gnum);
 123
 124         for (from = 0; from < ndx_count; from++) {
 125                 file = hlink_flist->sorted[ndx_list[from]];
 126                 gnum = F_HL_GNUM(file);
 127                 if (inc_recurse) {
 128                         node = hashtable_find(prior_hlinks, gnum, 1);
 129                         if (!node->data) {
 130                                 if (!(node->data = new_array0(char, 5)))
 131                                         out_of_memory("match_gnums");
 132                                 assert(gnum >= hlink_flist->ndx_start);
 133                                 file->flags |= FLAG_HLINK_FIRST;
 134                                 prev = -1;
 135                         } else if (CVAL(node->data, 0) == 0) {
 136                                 struct file_list *flist;
 137                                 prev = IVAL(node->data, 1);
 138                                 flist = flist_for_ndx(prev, NULL);
 139                                 if (flist)
 140                                         flist->files[prev - flist->ndx_start]->flags &= ~FLAG_HLINK_LAST;
 141                                 else {
 142                                         /* We skipped all prior files in this
 143                                          * group, so mark this as a "first". */
 144                                         file->flags |= FLAG_HLINK_FIRST;
 145                                         prev = -1;
 146                                 }
 147                         } else
 148                                 prev = -1;
 149                 } else {
 150                         file->flags |= FLAG_HLINK_FIRST;
 151                         prev = -1;
 152                 }
 153                 for ( ; from < ndx_count-1; file = file_next, gnum = gnum_next, from++) { /*SHARED ITERATOR*/
 154                         file_next = hlink_flist->sorted[ndx_list[from+1]];
 155                         gnum_next = F_HL_GNUM(file_next);
 156                         if (gnum != gnum_next)
 157                                 break;
 158                         F_HL_PREV(file) = prev;
 159                         /* The linked list uses over-the-wire ndx values. */
 160                         if (unsort_ndx)
 161                                 prev = F_NDX(file);
 162                         else
 163                                 prev = ndx_list[from] + hlink_flist->ndx_start;
 164                 }
 165                 if (prev < 0 && !inc_recurse) {
 166                         /* Disable hard-link bit and set DONE so that
 167                          * HLINK_BUMP()-dependent values are unaffected. */
 168                         file->flags &= ~(FLAG_HLINKED | FLAG_HLINK_FIRST);
 169                         file->flags |= FLAG_HLINK_DONE;
 170                         continue;
 171                 }
 172
 173                 file->flags |= FLAG_HLINK_LAST;
 174                 F_HL_PREV(file) = prev;
 175                 if (inc_recurse && CVAL(node->data, 0) == 0) {
 176                         if (unsort_ndx)
 177                                 prev = F_NDX(file);
 178                         else
 179                                 prev = ndx_list[from] + hlink_flist->ndx_start;
 180                         SIVAL(node->data, 1, prev);
 181                 }
 182         }
 183 }
 184
 185 /* Analyze the hard-links in the file-list by creating a list of all the
 186  * items that have hlink data, sorting them, and matching up identical
 187  * values into clusters.  These will be a single linked list from last
 188  * to first when we're done. */
 189 void match_hard_links(struct file_list *flist)
 190 {
 191         if (!list_only && flist->used) {
 192                 int i, ndx_count = 0;
 193                 int32 *ndx_list;
 194
 195                 if (!(ndx_list = new_array(int32, flist->used)))
 196                         out_of_memory("match_hard_links");
 197
 198                 for (i = 0; i < flist->used; i++) {
 199                         if (F_IS_HLINKED(flist->sorted[i]))
 200                                 ndx_list[ndx_count++] = i;
 201                 }
 202
 203                 hlink_flist = flist;
 204
 205                 if (ndx_count)
 206                         match_gnums(ndx_list, ndx_count);
 207
 208                 free(ndx_list);
 209         }
 210         if (protocol_version < 30)
 211                 idev_destroy();
 212 }
 213
 214 static int maybe_hard_link(struct file_struct *file, int ndx,
 215                            char *fname, int statret, stat_x *sxp,
 216                            const char *oldname, STRUCT_STAT *old_stp,
 217                            const char *realname, int itemizing, enum logcode code)
 218 {
 219         if (statret == 0) {
 220                 if (sxp->st.st_dev == old_stp->st_dev
 221                  && sxp->st.st_ino == old_stp->st_ino) {
 222                         if (itemizing) {
 223                                 itemize(fname, file, ndx, statret, sxp,
 224                                         ITEM_LOCAL_CHANGE | ITEM_XNAME_FOLLOWS,
 225                                         0, "");
 226                         }
 227                         if (INFO_GTE(NAME, 2) && maybe_ATTRS_REPORT)
 228                                 rprintf(FCLIENT, "%s is uptodate\n", fname);
 229                         file->flags |= FLAG_HLINK_DONE;
 230                         return 0;
 231                 }
 232         }
 233
 234         if (atomic_create(file, fname, NULL, oldname, MAKEDEV(0, 0), sxp, statret == 0 ? DEL_FOR_FILE : 0)) {
 235                 if (itemizing) {
 236                         itemize(fname, file, ndx, statret, sxp,
 237                                 ITEM_LOCAL_CHANGE | ITEM_XNAME_FOLLOWS, 0,
 238                                 realname);
 239                 }
 240                 if (code != FNONE && INFO_GTE(NAME, 1))
 241                         rprintf(code, "%s => %s\n", fname, realname);
 242                 return 0;
 243         }
 244
 245         return -1;
 246 }
 247
 248 /* Figure out if a prior entry is still there or if we just have a
 249  * cached name for it. */
 250 static char *check_prior(struct file_struct *file, int gnum,
 251                          int *prev_ndx_p, struct file_list **flist_p)
 252 {
 253         struct file_struct *fp;
 254         struct ht_int32_node *node;
 255         int prev_ndx = F_HL_PREV(file);
 256
 257         while (1) {
 258                 struct file_list *flist;
 259                 if (prev_ndx < 0
 260                  || (flist = flist_for_ndx(prev_ndx, NULL)) == NULL)
 261                         break;
 262                 fp = flist->files[prev_ndx - flist->ndx_start];
 263                 if (!(fp->flags & FLAG_SKIP_HLINK)) {
 264                         *prev_ndx_p = prev_ndx;
 265                         *flist_p = flist;
 266                         return NULL;
 267                 }
 268                 F_HL_PREV(file) = prev_ndx = F_HL_PREV(fp);
 269         }
 270
 271         if (inc_recurse
 272          && (node = hashtable_find(prior_hlinks, gnum, 0)) != NULL) {
 273                 assert(node->data != NULL);
 274                 if (CVAL(node->data, 0) != 0) {
 275                         *prev_ndx_p = -1;
 276                         *flist_p = NULL;
 277                         return node->data;
 278                 }
 279                 /* The prior file must have been skipped. */
 280                 F_HL_PREV(file) = -1;
 281         }
 282
 283         *prev_ndx_p = -1;
 284         *flist_p = NULL;
 285         return NULL;
 286 }
 287
 288 /* Only called if FLAG_HLINKED is set and FLAG_HLINK_FIRST is not.  Returns:
 289  * 0 = process the file, 1 = skip the file, -1 = error occurred. */
 290 int hard_link_check(struct file_struct *file, int ndx, char *fname,
 291                     int statret, stat_x *sxp, int itemizing,
 292                     enum logcode code)
 293 {
 294         STRUCT_STAT prev_st;
 295         char namebuf[MAXPATHLEN], altbuf[MAXPATHLEN];
 296         char *realname, *prev_name;
 297         struct file_list *flist;
 298         int gnum = inc_recurse ? F_HL_GNUM(file) : -1;
 299         int prev_ndx;
 300
 301         prev_name = realname = check_prior(file, gnum, &prev_ndx, &flist);
 302
 303         if (!prev_name) {
 304                 struct file_struct *prev_file;
 305
 306                 if (!flist) {
 307                         /* The previous file was skipped, so this one is
 308                          * treated as if it were the first in its group. */
 309                         if (DEBUG_GTE(HLINK, 2)) {
 310                                 rprintf(FINFO, "hlink for %d (%s,%d): virtual first\n",
 311                                         ndx, f_name(file, NULL), gnum);
 312                         }
 313                         return 0;
 314                 }
 315
 316                 prev_file = flist->files[prev_ndx - flist->ndx_start];
 317
 318                 /* Is the previous link not complete yet? */
 319                 if (!(prev_file->flags & FLAG_HLINK_DONE)) {
 320                         /* Is the previous link being transferred? */
 321                         if (prev_file->flags & FLAG_FILE_SENT) {
 322                                 /* Add ourselves to the list of files that will
 323                                  * be updated when the transfer completes, and
 324                                  * mark ourself as waiting for the transfer. */
 325                                 F_HL_PREV(file) = F_HL_PREV(prev_file);
 326                                 F_HL_PREV(prev_file) = ndx;
 327                                 file->flags |= FLAG_FILE_SENT;
 328                                 cur_flist->in_progress++;
 329                                 if (DEBUG_GTE(HLINK, 2)) {
 330                                         rprintf(FINFO, "hlink for %d (%s,%d): waiting for %d\n",
 331                                                 ndx, f_name(file, NULL), gnum, F_HL_PREV(file));
 332                                 }
 333                                 return 1;
 334                         }
 335                         if (DEBUG_GTE(HLINK, 2)) {
 336                                 rprintf(FINFO, "hlink for %d (%s,%d): looking for a leader\n",
 337                                         ndx, f_name(file, NULL), gnum);
 338                         }
 339                         return 0;
 340                 }
 341
 342                 /* There is a finished file to link with! */
 343                 if (!(prev_file->flags & FLAG_HLINK_FIRST)) {
 344                         /* The previous previous is FIRST when prev is not. */
 345                         prev_name = realname = check_prior(prev_file, gnum, &prev_ndx, &flist);
 346                         /* Update our previous pointer to point to the FIRST. */
 347                         F_HL_PREV(file) = prev_ndx;
 348                 }
 349
 350                 if (!prev_name) {
 351                         int alt_dest;
 352
 353                         assert(flist != NULL);
 354                         prev_file = flist->files[prev_ndx - flist->ndx_start];
 355                         /* F_HL_PREV() is alt_dest value when DONE && FIRST. */
 356                         alt_dest = F_HL_PREV(prev_file);
 357                         if (DEBUG_GTE(HLINK, 2)) {
 358                                 rprintf(FINFO, "hlink for %d (%s,%d): found flist match (alt %d)\n",
 359                                         ndx, f_name(file, NULL), gnum, alt_dest);
 360                         }
 361
 362                         if (alt_dest >= 0 && dry_run) {
 363                                 pathjoin(namebuf, MAXPATHLEN, basis_dir[alt_dest],
 364                                          f_name(prev_file, NULL));
 365                                 prev_name = namebuf;
 366                                 realname = f_name(prev_file, altbuf);
 367                         } else {
 368                                 prev_name = f_name(prev_file, namebuf);
 369                                 realname = prev_name;
 370                         }
 371                 }
 372         }
 373
 374         if (DEBUG_GTE(HLINK, 2)) {
 375                 rprintf(FINFO, "hlink for %d (%s,%d): leader is %d (%s)\n",
 376                         ndx, f_name(file, NULL), gnum, prev_ndx, prev_name);
 377         }
 378
 379         if (link_stat(prev_name, &prev_st, 0) < 0) {
 380                 if (!dry_run || errno != ENOENT) {
 381                         rsyserr(FERROR_XFER, errno, "stat %s failed", full_fname(prev_name));
 382                         return -1;
 383                 }
 384                 /* A new hard-link will get a new dev & inode, so approximate
 385                  * those values in dry-run mode by zeroing them. */
 386                 memset(&prev_st, 0, sizeof prev_st);
 387         }
 388
 389         if (statret < 0 && basis_dir[0] != NULL) {
 390                 /* If we match an alt-dest item, we don't output this as a change. */
 391                 char cmpbuf[MAXPATHLEN];
 392                 stat_x alt_sx;
 393                 int j = 0;
 394                 init_stat_x(&alt_sx);
 395                 do {
 396                         pathjoin(cmpbuf, MAXPATHLEN, basis_dir[j], fname);
 397                         if (link_stat(cmpbuf, &alt_sx.st, 0) < 0)
 398                                 continue;
 399                         if (link_dest) {
 400                                 if (prev_st.st_dev != alt_sx.st.st_dev
 401                                  || prev_st.st_ino != alt_sx.st.st_ino)
 402                                         continue;
 403                                 statret = 1;
 404                                 if (stdout_format_has_i == 0
 405                                  || (!INFO_GTE(NAME, 2) && stdout_format_has_i < 2)) {
 406                                         itemizing = 0;
 407                                         code = FNONE;
 408                                         if (INFO_GTE(NAME, 2) && maybe_ATTRS_REPORT)
 409                                                 rprintf(FCLIENT, "%s is uptodate\n", fname);
 410                                 }
 411                                 break;
 412                         }
 413                         if (!unchanged_file(cmpbuf, file, &alt_sx.st))
 414                                 continue;
 415                         statret = 1;
 416                         if (unchanged_attrs(cmpbuf, file, &alt_sx))
 417                                 break;
 418                 } while (basis_dir[++j] != NULL);
 419                 if (statret == 1) {
 420                         sxp->st = alt_sx.st;
 421 #ifdef SUPPORT_ACLS
 422                         if (preserve_acls && !S_ISLNK(file->mode)) {
 423                                 free_acl(sxp);
 424                                 if (!ACL_READY(alt_sx))
 425                                         get_acl(cmpbuf, sxp);
 426                                 else {
 427                                         sxp->acc_acl = alt_sx.acc_acl;
 428                                         sxp->def_acl = alt_sx.def_acl;
 429                                         alt_sx.acc_acl = alt_sx.def_acl = NULL;
 430                                 }
 431                         }
 432 #endif
 433 #ifdef SUPPORT_XATTRS
 434                         if (preserve_xattrs) {
 435                                 free_xattr(sxp);
 436                                 if (!XATTR_READY(alt_sx))
 437                                         get_xattr(cmpbuf, sxp);
 438                                 else {
 439                                         sxp->xattr = alt_sx.xattr;
 440                                         alt_sx.xattr = NULL;
 441                                 }
 442                         }
 443 #endif
 444                 } else
 445                         free_stat_x(&alt_sx);
 446         }
 447
 448         if (maybe_hard_link(file, ndx, fname, statret, sxp, prev_name, &prev_st,
 449                             realname, itemizing, code) < 0)
 450                 return -1;
 451
 452         if (remove_source_files == 1 && do_xfers)
 453                 send_msg_int(MSG_SUCCESS, ndx);
 454
 455         return 1;
 456 }
 457
 458 int hard_link_one(struct file_struct *file, const char *fname,
 459                   const char *oldname, int terse)
 460 {
 461         if (do_link(oldname, fname) < 0) {
 462                 enum logcode code;
 463                 if (terse) {
 464                         if (!INFO_GTE(NAME, 1))
 465                                 return 0;
 466                         code = FINFO;
 467                 } else
 468                         code = FERROR_XFER;
 469                 rsyserr(code, errno, "link %s => %s failed",
 470                         full_fname(fname), oldname);
 471                 return 0;
 472         }
 473
 474         file->flags |= FLAG_HLINK_DONE;
 475
 476         return 1;
 477 }
 478
 479 void finish_hard_link(struct file_struct *file, const char *fname, int fin_ndx,
 480                       STRUCT_STAT *stp, int itemizing, enum logcode code,
 481                       int alt_dest)
 482 {
 483         stat_x prev_sx;
 484         STRUCT_STAT st;
 485         char prev_name[MAXPATHLEN], alt_name[MAXPATHLEN];
 486         const char *our_name;
 487         struct file_list *flist;
 488         int prev_statret, ndx, prev_ndx = F_HL_PREV(file);
 489
 490         if (stp == NULL && prev_ndx >= 0) {
 491                 if (link_stat(fname, &st, 0) < 0 && !dry_run) {
 492                         rsyserr(FERROR_XFER, errno, "stat %s failed",
 493                                 full_fname(fname));
 494                         return;
 495                 }
 496                 stp = &st;
 497         }
 498
 499         /* FIRST combined with DONE means we were the first to get done. */
 500         file->flags |= FLAG_HLINK_FIRST | FLAG_HLINK_DONE;
 501         F_HL_PREV(file) = alt_dest;
 502         if (alt_dest >= 0 && dry_run) {
 503                 pathjoin(alt_name, MAXPATHLEN, basis_dir[alt_dest],
 504                          f_name(file, NULL));
 505                 our_name = alt_name;
 506         } else
 507                 our_name = fname;
 508
 509         init_stat_x(&prev_sx);
 510
 511         while ((ndx = prev_ndx) >= 0) {
 512                 int val;
 513                 flist = flist_for_ndx(ndx, "finish_hard_link");
 514                 file = flist->files[ndx - flist->ndx_start];
 515                 file->flags = (file->flags & ~FLAG_HLINK_FIRST) | FLAG_HLINK_DONE;
 516                 prev_ndx = F_HL_PREV(file);
 517                 F_HL_PREV(file) = fin_ndx;
 518                 prev_statret = link_stat(f_name(file, prev_name), &prev_sx.st, 0);
 519                 val = maybe_hard_link(file, ndx, prev_name, prev_statret, &prev_sx,
 520                                       our_name, stp, fname, itemizing, code);
 521                 flist->in_progress--;
 522                 free_stat_x(&prev_sx);
 523                 if (val < 0)
 524                         continue;
 525                 if (remove_source_files == 1 && do_xfers)
 526                         send_msg_int(MSG_SUCCESS, ndx);
 527         }
 528
 529         if (inc_recurse) {
 530                 int gnum = F_HL_GNUM(file);
 531                 struct ht_int32_node *node = hashtable_find(prior_hlinks, gnum, 0);
 532                 if (node == NULL) {
 533                         rprintf(FERROR, "Unable to find a hlink node for %d (%s)\n", gnum, f_name(file, prev_name));
 534                         exit_cleanup(RERR_MESSAGEIO);
 535                 }
 536                 if (node->data == NULL) {
 537                         rprintf(FERROR, "Hlink node data for %d is NULL (%s)\n", gnum, f_name(file, prev_name));
 538                         exit_cleanup(RERR_MESSAGEIO);
 539                 }
 540                 if (CVAL(node->data, 0) != 0) {
 541                         rprintf(FERROR, "Hlink node data for %d already has path=%s (%s)\n",
 542                                 gnum, (char*)node->data, f_name(file, prev_name));
 543                         exit_cleanup(RERR_MESSAGEIO);
 544                 }
 545                 free(node->data);
 546                 if (!(node->data = strdup(our_name)))
 547                         out_of_memory("finish_hard_link");
 548         }
 549 }
 550
 551 int skip_hard_link(struct file_struct *file, struct file_list **flist_p)
 552 {
 553         struct file_list *flist;
 554         int prev_ndx;
 555
 556         file->flags |= FLAG_SKIP_HLINK;
 557         if (!(file->flags & FLAG_HLINK_LAST))
 558                 return -1;
 559
 560         check_prior(file, F_HL_GNUM(file), &prev_ndx, &flist);
 561         if (prev_ndx >= 0) {
 562                 file = flist->files[prev_ndx - flist->ndx_start];
 563                 if (file->flags & (FLAG_HLINK_DONE|FLAG_FILE_SENT))
 564                         return -1;
 565                 file->flags |= FLAG_HLINK_LAST;
 566                 *flist_p = flist;
 567         }
 568
 569         return prev_ndx;
 570 }
 571 #endif