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