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, 2005, 2006 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 2 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, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
  22  */
  23
  24 #include "rsync.h"
  25
  26 extern int verbose;
  27 extern int dry_run;
  28 extern int do_xfers;
  29 extern int link_dest;
  30 extern int make_backups;
  31 extern int protocol_version;
  32 extern int remove_source_files;
  33 extern int stdout_format_has_i;
  34 extern int maybe_ATTRS_REPORT;
  35 extern char *basis_dir[];
  36 extern struct file_list *the_file_list;
  37
  38 #ifdef SUPPORT_HARD_LINKS
  39
  40 alloc_pool_t hlink_pool;
  41
  42 #define HASH_LOAD_LIMIT(size) ((size)*3/4)
  43 #define FPTR(i) (the_file_list->files[i])
  44
  45 struct ihash_table {
  46         int32 size;
  47         int32 entries;
  48         struct idev_node *buckets;
  49 } *dev_tbl;
  50
  51 static struct idev_node *ihash_node(struct ihash_table *tbl, int64 key);
  52
  53 /* Starting with protocol 30, we use a simple hashtable on the sending side
  54  * for hashing the st_dev and st_ino info.  The receiving side gets told
  55  * (via flags and a "group index") which items are hard-linked together, so
  56  * we can avoid the pool of dev+inode data. */
  57
  58 static struct ihash_table *ihash_create(int size)
  59 {
  60         struct ihash_table *tbl;
  61
  62         /* Pick a power of 2 that can hold the requested size. */
  63         if (size & (size-1)) {
  64                 int req = size;
  65                 size = 32;
  66                 while (size < req)
  67                         size *= 2;
  68         }
  69
  70         if (!(tbl = new(struct ihash_table))
  71          || !(tbl->buckets = new_array(struct idev_node, size)))
  72                 out_of_memory("ihash_create");
  73         memset(tbl->buckets, 0, size * sizeof tbl->buckets[0]);
  74         tbl->size = size;
  75         tbl->entries = 0;
  76
  77         return tbl;
  78 }
  79
  80 static void ihash_destroy(struct ihash_table *tbl)
  81 {
  82         free(tbl->buckets);
  83         free(tbl);
  84 }
  85
  86 void init_hard_links(void)
  87 {
  88         if (protocol_version >= 30) {
  89                 dev_tbl = ihash_create(16);
  90                 return;
  91         }
  92
  93         if (!(hlink_pool = pool_create(HLINK_EXTENT, sizeof (struct idev),
  94                                        out_of_memory, POOL_INTERN)))
  95                 out_of_memory("init_hard_links");
  96 }
  97
  98 static void expand_ihash(struct ihash_table *tbl)
  99 {
 100         struct idev_node *old_buckets;
 101         int size = tbl->size * 2;
 102         int i;
 103
 104         old_buckets = tbl->buckets;
 105         if (!(tbl->buckets = new_array(struct idev_node, size)))
 106                 out_of_memory("ihash_create");
 107         memset(tbl->buckets, 0, size * sizeof tbl->buckets[0]);
 108         tbl->size = size;
 109         tbl->entries = 0;
 110
 111         for (i = size / 2; i-- > 0; ) {
 112                 int64 key = old_buckets[i].key;
 113                 if (key == 0)
 114                         continue;
 115                 ihash_node(tbl, key)->data = old_buckets[i].data;
 116         }
 117
 118         free(old_buckets);
 119 }
 120
 121 /* This returns the node for the indicated key, either newly created,
 122  * or already existing. */
 123 static struct idev_node *ihash_node(struct ihash_table *tbl, int64 key)
 124 {
 125         uint32 bkt;
 126
 127         if (tbl->entries > HASH_LOAD_LIMIT(tbl->size))
 128                 expand_ihash(tbl);
 129
 130 #if SIZEOF_INT64 < 8
 131         /* Based on Jenkins One-at-a-time hash. */
 132         {
 133                 uchar *keyp = (uchar*)&key;
 134                 int i;
 135
 136                 for (bkt = 0, i = 0; i < SIZEOF_INT64; i++) {
 137                         bkt += keyp[i];
 138                         bkt += (bkt << 10);
 139                         bkt ^= (bkt >> 6);
 140                 }
 141                 bkt += (bkt << 3);
 142                 bkt ^= (bkt >> 11);
 143                 bkt += (bkt << 15);
 144         }
 145 #else
 146 #define rot(x,k) (((x)<<(k)) ^ ((x)>>(32-(k))))
 147         /* Based on Jenkins hashword() from lookup3.c. */
 148         {
 149                 uint32 a, b, c;
 150
 151                 /* Set up the internal state */
 152                 a = b = c = 0xdeadbeef + (8 << 2);
 153
 154                 b += (uint32)(key >> 32);
 155                 a += (uint32)key;
 156                 c ^= b; c -= rot(b, 14);
 157                 a ^= c; a -= rot(c, 11);
 158                 b ^= a; b -= rot(a, 25);
 159                 c ^= b; c -= rot(b, 16);
 160                 a ^= c; a -= rot(c, 4);
 161                 b ^= a; b -= rot(a, 14);
 162                 c ^= b; c -= rot(b, 24);
 163                 bkt = c;
 164         }
 165 #endif
 166
 167         /* If it already exists, return it. */
 168         while (1) {
 169                 bkt &= tbl->size - 1;
 170                 if (tbl->buckets[bkt].key == key)
 171                         return &tbl->buckets[bkt];
 172                 if (tbl->buckets[bkt].key == 0)
 173                         break;
 174                 bkt++;
 175         }
 176
 177         /* Otherwise, take over this empty spot and then return it. */
 178         tbl->buckets[bkt].key = key;
 179         tbl->entries++;
 180         return &tbl->buckets[bkt];
 181 }
 182
 183 struct idev_node *idev_node(int64 dev, int64 ino)
 184 {
 185         static struct idev_node *dev_node = NULL;
 186         struct ihash_table *tbl;
 187
 188         if (!dev_node || dev_node->key != dev) {
 189                 /* We keep a separate hash table of inodes for every device. */
 190                 dev_node = ihash_node(dev_tbl, dev);
 191                 if (!(tbl = dev_node->data))
 192                         tbl = dev_node->data = ihash_create(512);
 193         } else
 194                 tbl = dev_node->data;
 195
 196         return ihash_node(tbl, ino);
 197 }
 198
 199 void idev_destroy(void)
 200 {
 201         int i;
 202
 203         for (i = 0; i < dev_tbl->size; i++) {
 204                 if (dev_tbl->buckets[i].data)
 205                         ihash_destroy(dev_tbl->buckets[i].data);
 206         }
 207
 208         ihash_destroy(dev_tbl);
 209 }
 210
 211 /* This routine compares dev+inode info for protocols < 30. */
 212 static int hlink_compare_idev(int *int1, int *int2)
 213 {
 214         struct file_struct *f1 = FPTR(*int1);
 215         struct file_struct *f2 = FPTR(*int2);
 216         struct idev *i1 = F_HL_IDEV(f1);
 217         struct idev *i2 = F_HL_IDEV(f2);
 218
 219         if (i1->dev != i2->dev)
 220                 return i1->dev > i2->dev ? 1 : -1;
 221
 222         if (i1->ino != i2->ino)
 223                 return i1->ino > i2->ino ? 1 : -1;
 224
 225         return *int1 > *int2 ? 1 : -1;
 226 }
 227
 228 /* This routine compares group numbers for protocols >= 30. */
 229 static int hlink_compare_gnum(int *int1, int *int2)
 230 {
 231         struct file_struct *f1 = FPTR(*int1);
 232         struct file_struct *f2 = FPTR(*int2);
 233         int gnum1 = F_HL_GNUM(f1);
 234         int gnum2 = F_HL_GNUM(f2);
 235
 236         if (gnum1 != gnum2)
 237                 return gnum1 > gnum2 ? 1 : -1;
 238
 239         return *int1 > *int2 ? 1 : -1;
 240 }
 241
 242 /* The match routine for protocols < 30. */
 243 static void match_idevs(int32 *ndx_list, int ndx_count)
 244 {
 245         int32 from, prev;
 246         struct file_struct *file, *file_next;
 247         struct idev *idev, *idev_next;
 248
 249         qsort(ndx_list, ndx_count, sizeof ndx_list[0],
 250              (int (*)()) hlink_compare_idev);
 251
 252         for (from = 0; from < ndx_count; from++) {
 253                 for (file = FPTR(ndx_list[from]), idev = F_HL_IDEV(file), prev = -1;
 254                      from < ndx_count-1;
 255                      file = file_next, idev = idev_next, prev = ndx_list[from++])
 256                 {
 257                         file_next = FPTR(ndx_list[from+1]);
 258                         idev_next = F_HL_IDEV(file_next);
 259                         if (idev->dev != idev_next->dev || idev->ino != idev_next->ino)
 260                                 break;
 261                         pool_free(hlink_pool, 0, idev);
 262                         if (prev < 0)
 263                                 file->flags |= FLAG_HLINK_FIRST;
 264                         F_HL_PREV(file) = prev;
 265                 }
 266                 pool_free(hlink_pool, 0, idev);
 267                 if (prev < 0)
 268                         file->flags &= ~FLAG_HLINKED;
 269                 else {
 270                         file->flags |= FLAG_HLINK_LAST;
 271                         F_HL_PREV(file) = prev;
 272                 }
 273         }
 274 }
 275
 276 /* The match routine for protocols >= 30. */
 277 static void match_gnums(int32 *ndx_list, int ndx_count)
 278 {
 279         int32 from, prev;
 280         struct file_struct *file, *file_next;
 281         int gnum, gnum_next;
 282
 283         qsort(ndx_list, ndx_count, sizeof ndx_list[0],
 284              (int (*)()) hlink_compare_gnum);
 285
 286         for (from = 0; from < ndx_count; from++) {
 287                 for (file = FPTR(ndx_list[from]), gnum = F_HL_GNUM(file), prev = -1;
 288                      from < ndx_count-1;
 289                      file = file_next, gnum = gnum_next, prev = ndx_list[from++])
 290                 {
 291                         file_next = FPTR(ndx_list[from+1]);
 292                         gnum_next = F_HL_GNUM(file_next);
 293                         if (gnum != gnum_next)
 294                                 break;
 295                         if (prev < 0)
 296                                 file->flags |= FLAG_HLINK_FIRST;
 297                         F_HL_PREV(file) = prev;
 298                 }
 299                 if (prev < 0)
 300                         file->flags &= ~FLAG_HLINKED;
 301                 else {
 302                         file->flags |= FLAG_HLINK_LAST;
 303                         F_HL_PREV(file) = prev;
 304                 }
 305         }
 306 }
 307
 308 /* Analyze the hard-links in the file-list by creating a list of all the
 309  * items that have hlink data, sorting them, and matching up identical
 310  * values into clusters.  These will be a single linked list from last
 311  * to first when we're done. */
 312 void match_hard_links(void)
 313 {
 314         int i, ndx_count = 0;
 315         int32 *ndx_list;
 316
 317         if (!(ndx_list = new_array(int32, the_file_list->count)))
 318                 out_of_memory("match_hard_links");
 319
 320         for (i = 0; i < the_file_list->count; i++) {
 321                 if (F_IS_HLINKED(FPTR(i)))
 322                         ndx_list[ndx_count++] = i;
 323         }
 324
 325         if (ndx_count) {
 326                 if (protocol_version >= 30)
 327                         match_gnums(ndx_list, ndx_count);
 328                 else {
 329                         match_idevs(ndx_list, ndx_count);
 330                         pool_destroy(hlink_pool);
 331                 }
 332         }
 333         free(ndx_list);
 334 }
 335
 336 static int maybe_hard_link(struct file_struct *file, int ndx,
 337                            const char *fname, int statret, STRUCT_STAT *stp,
 338                            const char *oldname, STRUCT_STAT *old_stp,
 339                            const char *realname, int itemizing, enum logcode code)
 340 {
 341         if (statret == 0) {
 342                 if (stp->st_dev == old_stp->st_dev
 343                  && stp->st_ino == old_stp->st_ino) {
 344                         if (itemizing) {
 345                                 itemize(file, ndx, statret, stp,
 346                                         ITEM_LOCAL_CHANGE | ITEM_XNAME_FOLLOWS,
 347                                         0, "");
 348                         }
 349                         if (verbose > 1 && maybe_ATTRS_REPORT)
 350                                 rprintf(FCLIENT, "%s is uptodate\n", fname);
 351                         file->flags |= FLAG_HLINK_DONE;
 352                         return 0;
 353                 }
 354                 if (make_backups) {
 355                         if (!make_backup(fname))
 356                                 return -1;
 357                 } else if (robust_unlink(fname)) {
 358                         rsyserr(FERROR, errno, "unlink %s failed",
 359                                 full_fname(fname));
 360                         return -1;
 361                 }
 362         }
 363
 364         if (hard_link_one(file, fname, oldname, 0)) {
 365                 if (itemizing) {
 366                         itemize(file, ndx, statret, stp,
 367                                 ITEM_LOCAL_CHANGE | ITEM_XNAME_FOLLOWS, 0,
 368                                 realname);
 369                 }
 370                 if (code != FNONE && verbose)
 371                         rprintf(code, "%s => %s\n", fname, realname);
 372                 return 0;
 373         }
 374         return -1;
 375 }
 376
 377 /* Only called if FLAG_HLINKED is set and FLAG_HLINK_FIRST is not.  Returns:
 378  * 0 = process the file, 1 = skip the file, -1 = error occurred. */
 379 int hard_link_check(struct file_struct *file, int ndx, const char *fname,
 380                     int statret, STRUCT_STAT *stp, int itemizing,
 381                     enum logcode code)
 382 {
 383         STRUCT_STAT prev_st;
 384         char prev_name[MAXPATHLEN], altbuf[MAXPATHLEN], *realname;
 385         int alt_dest, prev_ndx = F_HL_PREV(file);
 386         struct file_struct *prev_file = FPTR(prev_ndx);
 387
 388         /* Is the previous link is not complete yet? */
 389         if (!(prev_file->flags & FLAG_HLINK_DONE)) {
 390                 /* Is the previous link being transferred? */
 391                 if (prev_file->flags & FLAG_SENT) {
 392                         /* Add ourselves to the list of files that will be
 393                          * updated when the transfer completes, and mark
 394                          * ourself as waiting for the transfer. */
 395                         F_HL_PREV(file) = F_HL_PREV(prev_file);
 396                         F_HL_PREV(prev_file) = ndx;
 397                         file->flags |= FLAG_SENT;
 398                         return 1;
 399                 }
 400                 return 0;
 401         }
 402
 403         /* There is a finished file to link with! */
 404         if (!(prev_file->flags & FLAG_HLINK_FIRST)) {
 405                 /* The previous previous will be marked with FIRST. */
 406                 prev_ndx = F_HL_PREV(prev_file);
 407                 prev_file = FPTR(prev_ndx);
 408                 /* Update our previous pointer to point to the first. */
 409                 F_HL_PREV(file) = prev_ndx;
 410         }
 411         alt_dest = F_HL_PREV(prev_file); /* alternate value when DONE && FIRST */
 412         if (alt_dest >= 0 && dry_run) {
 413                 pathjoin(prev_name, MAXPATHLEN, basis_dir[alt_dest],
 414                          f_name(prev_file, NULL));
 415                 f_name(prev_file, altbuf);
 416                 realname = altbuf;
 417         } else {
 418                 f_name(prev_file, prev_name);
 419                 realname = prev_name;
 420         }
 421
 422         if (link_stat(prev_name, &prev_st, 0) < 0) {
 423                 rsyserr(FERROR, errno, "stat %s failed",
 424                         full_fname(prev_name));
 425                 return -1;
 426         }
 427
 428         if (statret < 0 && basis_dir[0] != NULL) {
 429                 /* If we match an alt-dest item, we don't output this as a change. */
 430                 char cmpbuf[MAXPATHLEN];
 431                 STRUCT_STAT alt_st;
 432                 int j = 0;
 433                 do {
 434                         pathjoin(cmpbuf, MAXPATHLEN, basis_dir[j], fname);
 435                         if (link_stat(cmpbuf, &alt_st, 0) < 0)
 436                                 continue;
 437                         if (link_dest) {
 438                                 if (prev_st.st_dev != alt_st.st_dev
 439                                  || prev_st.st_ino != alt_st.st_ino)
 440                                         continue;
 441                                 statret = 1;
 442                                 *stp = alt_st;
 443                                 if (verbose < 2 || !stdout_format_has_i) {
 444                                         itemizing = 0;
 445                                         code = FNONE;
 446                                         if (verbose > 1 && maybe_ATTRS_REPORT)
 447                                                 rprintf(FCLIENT, "%s is uptodate\n", fname);
 448                                 }
 449                                 break;
 450                         }
 451                         if (!unchanged_file(cmpbuf, file, &alt_st))
 452                                 continue;
 453                         statret = 1;
 454                         *stp = alt_st;
 455                         if (unchanged_attrs(file, &alt_st))
 456                                 break;
 457                 } while (basis_dir[++j] != NULL);
 458         }
 459
 460         if (maybe_hard_link(file, ndx, fname, statret, stp, prev_name, &prev_st,
 461                             realname, itemizing, code) < 0)
 462                 return -1;
 463
 464         if (remove_source_files == 1 && do_xfers)
 465                 send_msg_int(MSG_SUCCESS, ndx);
 466
 467         return 1;
 468 }
 469
 470 int hard_link_one(struct file_struct *file, const char *fname,
 471                   const char *oldname, int terse)
 472 {
 473         if (do_link(oldname, fname) < 0) {
 474                 enum logcode code;
 475                 if (terse) {
 476                         if (!verbose)
 477                                 return -1;
 478                         code = FINFO;
 479                 } else
 480                         code = FERROR;
 481                 rsyserr(code, errno, "link %s => %s failed",
 482                         full_fname(fname), oldname);
 483                 return 0;
 484         }
 485
 486         file->flags |= FLAG_HLINK_DONE;
 487
 488         return 1;
 489 }
 490
 491 void finish_hard_link(struct file_struct *file, const char *fname,
 492                       STRUCT_STAT *stp, int itemizing, enum logcode code,
 493                       int alt_dest)
 494 {
 495         STRUCT_STAT st, prev_st;
 496         char alt_name[MAXPATHLEN], *prev_name;
 497         const char *our_name;
 498         int prev_statret, ndx, prev_ndx = F_HL_PREV(file);
 499
 500         if (stp == NULL && prev_ndx >= 0) {
 501                 if (link_stat(fname, &st, 0) < 0) {
 502                         rsyserr(FERROR, errno, "stat %s failed",
 503                                 full_fname(fname));
 504                         return;
 505                 }
 506                 stp = &st;
 507         }
 508
 509         /* FIRST combined with DONE means we were the first to get done. */
 510         file->flags |= FLAG_HLINK_FIRST | FLAG_HLINK_DONE;
 511         F_HL_PREV(file) = alt_dest;
 512         if (alt_dest >= 0 && dry_run) {
 513                 pathjoin(alt_name, MAXPATHLEN, basis_dir[alt_dest],
 514                          f_name(file, NULL));
 515                 our_name = alt_name;
 516         } else
 517                 our_name = fname;
 518
 519         while ((ndx = prev_ndx) >= 0) {
 520                 file = FPTR(ndx);
 521                 file->flags = (file->flags & ~FLAG_HLINK_FIRST) | FLAG_HLINK_DONE;
 522                 prev_ndx = F_HL_PREV(file);
 523                 prev_name = f_name(file, NULL);
 524                 prev_statret = link_stat(prev_name, &prev_st, 0);
 525                 if (maybe_hard_link(file, ndx, prev_name, prev_statret, &prev_st,
 526                                     our_name, stp, fname, itemizing, code) < 0)
 527                         continue;
 528                 if (remove_source_files == 1 && do_xfers)
 529                         send_msg_int(MSG_SUCCESS, ndx);
 530         }
 531 }
 532 #endif