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 version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
  21  */
  22
  23 #include "rsync.h"
  24
  25 extern int verbose;
  26 extern int dry_run;
  27 extern int do_xfers;
  28 extern int link_dest;
  29 extern int preserve_acls;
  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 *cur_flist;
  37 #ifdef ICONV_OPTION
  38 extern int ic_ndx;
  39 #endif
  40
  41 #ifdef SUPPORT_HARD_LINKS
  42
  43 #define HASH_LOAD_LIMIT(size) ((size)*3/4)
  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) || size < 16) {
  64                 int req = size;
  65                 size = 16;
  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         dev_tbl = ihash_create(16);
  89 }
  90
  91 static void expand_ihash(struct ihash_table *tbl)
  92 {
  93         struct idev_node *old_buckets = tbl->buckets;
  94         int size = tbl->size * 2;
  95         int i;
  96
  97         if (!(tbl->buckets = new_array(struct idev_node, size)))
  98                 out_of_memory("ihash_create");
  99         memset(tbl->buckets, 0, size * sizeof (struct idev_node));
 100         tbl->size = size;
 101         tbl->entries = 0;
 102
 103         for (i = size / 2; i-- > 0; ) {
 104                 int64 key = old_buckets[i].key;
 105                 if (key == 0)
 106                         continue;
 107                 ihash_node(tbl, key)->data = old_buckets[i].data;
 108         }
 109
 110         free(old_buckets);
 111 }
 112
 113 /* This returns the node for the indicated key, either newly created,
 114  * or already existing. */
 115 static struct idev_node *ihash_node(struct ihash_table *tbl, int64 key)
 116 {
 117         uint32 bkt;
 118
 119         if (tbl->entries > HASH_LOAD_LIMIT(tbl->size))
 120                 expand_ihash(tbl);
 121
 122 #if SIZEOF_INT64 < 8
 123         /* Based on Jenkins One-at-a-time hash. */
 124         {
 125                 uchar *keyp = (uchar*)&key;
 126                 int i;
 127
 128                 for (bkt = 0, i = 0; i < SIZEOF_INT64; i++) {
 129                         bkt += keyp[i];
 130                         bkt += (bkt << 10);
 131                         bkt ^= (bkt >> 6);
 132                 }
 133                 bkt += (bkt << 3);
 134                 bkt ^= (bkt >> 11);
 135                 bkt += (bkt << 15);
 136         }
 137 #else
 138 #define rot(x,k) (((x)<<(k)) ^ ((x)>>(32-(k))))
 139         /* Based on Jenkins hashword() from lookup3.c. */
 140         {
 141                 uint32 a, b, c;
 142
 143                 /* Set up the internal state */
 144                 a = b = c = 0xdeadbeef + (8 << 2);
 145
 146                 b += (uint32)(key >> 32);
 147                 a += (uint32)key;
 148                 c ^= b; c -= rot(b, 14);
 149                 a ^= c; a -= rot(c, 11);
 150                 b ^= a; b -= rot(a, 25);
 151                 c ^= b; c -= rot(b, 16);
 152                 a ^= c; a -= rot(c, 4);
 153                 b ^= a; b -= rot(a, 14);
 154                 c ^= b; c -= rot(b, 24);
 155                 bkt = c;
 156         }
 157 #endif
 158
 159         /* If it already exists, return it. */
 160         while (1) {
 161                 bkt &= tbl->size - 1;
 162                 if (tbl->buckets[bkt].key == key)
 163                         return &tbl->buckets[bkt];
 164                 if (tbl->buckets[bkt].key == 0)
 165                         break;
 166                 bkt++;
 167         }
 168
 169         /* Otherwise, take over this empty spot and then return it. */
 170         tbl->buckets[bkt].key = key;
 171         tbl->entries++;
 172         return &tbl->buckets[bkt];
 173 }
 174
 175 struct idev_node *idev_node(int64 dev, int64 ino)
 176 {
 177         static struct idev_node *dev_node = NULL;
 178         struct ihash_table *tbl;
 179
 180         if (!dev_node || dev_node->key != dev) {
 181                 /* We keep a separate hash table of inodes for every device. */
 182                 dev_node = ihash_node(dev_tbl, dev);
 183                 if (!(tbl = dev_node->data))
 184                         tbl = dev_node->data = ihash_create(512);
 185         } else
 186                 tbl = dev_node->data;
 187
 188         return ihash_node(tbl, ino);
 189 }
 190
 191 void idev_destroy(void)
 192 {
 193         int i;
 194
 195         for (i = 0; i < dev_tbl->size; i++) {
 196                 if (dev_tbl->buckets[i].data)
 197                         ihash_destroy(dev_tbl->buckets[i].data);
 198         }
 199
 200         ihash_destroy(dev_tbl);
 201 }
 202
 203 static int hlink_compare_gnum(int *int1, int *int2)
 204 {
 205         struct file_struct *f1 = cur_flist->sorted[*int1];
 206         struct file_struct *f2 = cur_flist->sorted[*int2];
 207         int32 gnum1 = F_HL_GNUM(f1);
 208         int32 gnum2 = F_HL_GNUM(f2);
 209
 210         if (gnum1 != gnum2)
 211                 return gnum1 > gnum2 ? 1 : -1;
 212
 213         return *int1 > *int2 ? 1 : -1;
 214 }
 215
 216 static void match_gnums(int32 *ndx_list, int ndx_count)
 217 {
 218         int32 from, prev;
 219         struct file_struct *file, *file_next;
 220         int32 gnum, gnum_next;
 221
 222         qsort(ndx_list, ndx_count, sizeof ndx_list[0],
 223              (int (*)()) hlink_compare_gnum);
 224
 225         for (from = 0; from < ndx_count; from++) {
 226                 for (file = cur_flist->sorted[ndx_list[from]], gnum = F_HL_GNUM(file), prev = -1;
 227                      from < ndx_count-1;
 228                      file = file_next, gnum = gnum_next, from++) /*SHARED ITERATOR*/
 229                 {
 230                         file_next = cur_flist->sorted[ndx_list[from+1]];
 231                         gnum_next = F_HL_GNUM(file_next);
 232                         if (gnum != gnum_next)
 233                                 break;
 234                         if (prev < 0)
 235                                 file->flags |= FLAG_HLINK_FIRST;
 236                         F_HL_PREV(file) = prev;
 237                         /* The linked list must use raw ndx values. */
 238 #ifdef ICONV_OPTION
 239                         if (ic_ndx)
 240                                 prev = F_NDX(file);
 241                         else
 242 #endif
 243                                 prev = ndx_list[from];
 244                 }
 245                 if (prev < 0)
 246                         file->flags &= ~FLAG_HLINKED;
 247                 else {
 248                         file->flags |= FLAG_HLINK_LAST;
 249                         F_HL_PREV(file) = prev;
 250                 }
 251         }
 252 }
 253
 254 /* Analyze the hard-links in the file-list by creating a list of all the
 255  * items that have hlink data, sorting them, and matching up identical
 256  * values into clusters.  These will be a single linked list from last
 257  * to first when we're done. */
 258 void match_hard_links(void)
 259 {
 260         int i, ndx_count = 0;
 261         int32 *ndx_list;
 262
 263         if (!(ndx_list = new_array(int32, cur_flist->count)))
 264                 out_of_memory("match_hard_links");
 265
 266         for (i = 0; i < cur_flist->count; i++) {
 267                 if (F_IS_HLINKED(cur_flist->sorted[i]))
 268                         ndx_list[ndx_count++] = i;
 269         }
 270
 271         if (ndx_count)
 272                 match_gnums(ndx_list, ndx_count);
 273
 274         free(ndx_list);
 275         if (protocol_version < 30)
 276                 idev_destroy();
 277 }
 278
 279 static int maybe_hard_link(struct file_struct *file, int ndx,
 280                            const char *fname, int statret, statx *sxp,
 281                            const char *oldname, STRUCT_STAT *old_stp,
 282                            const char *realname, int itemizing, enum logcode code)
 283 {
 284         if (statret == 0) {
 285                 if (sxp->st.st_dev == old_stp->st_dev
 286                  && sxp->st.st_ino == old_stp->st_ino) {
 287                         if (itemizing) {
 288                                 itemize(fname, file, ndx, statret, sxp,
 289                                         ITEM_LOCAL_CHANGE | ITEM_XNAME_FOLLOWS,
 290                                         0, "");
 291                         }
 292                         if (verbose > 1 && maybe_ATTRS_REPORT)
 293                                 rprintf(FCLIENT, "%s is uptodate\n", fname);
 294                         file->flags |= FLAG_HLINK_DONE;
 295                         return 0;
 296                 }
 297                 if (make_backups > 0) {
 298                         if (!make_backup(fname))
 299                                 return -1;
 300                 } else if (robust_unlink(fname)) {
 301                         rsyserr(FERROR, errno, "unlink %s failed",
 302                                 full_fname(fname));
 303                         return -1;
 304                 }
 305         }
 306
 307         if (hard_link_one(file, fname, oldname, 0)) {
 308                 if (itemizing) {
 309                         itemize(fname, file, ndx, statret, sxp,
 310                                 ITEM_LOCAL_CHANGE | ITEM_XNAME_FOLLOWS, 0,
 311                                 realname);
 312                 }
 313                 if (code != FNONE && verbose)
 314                         rprintf(code, "%s => %s\n", fname, realname);
 315                 return 0;
 316         }
 317         return -1;
 318 }
 319
 320 /* Only called if FLAG_HLINKED is set and FLAG_HLINK_FIRST is not.  Returns:
 321  * 0 = process the file, 1 = skip the file, -1 = error occurred. */
 322 int hard_link_check(struct file_struct *file, int ndx, const char *fname,
 323                     int statret, statx *sxp, int itemizing,
 324                     enum logcode code)
 325 {
 326         STRUCT_STAT prev_st;
 327         char prev_name[MAXPATHLEN], altbuf[MAXPATHLEN], *realname;
 328         int alt_dest, prev_ndx = F_HL_PREV(file);
 329         struct file_struct *prev_file = cur_flist->files[prev_ndx];
 330
 331         /* Is the previous link is not complete yet? */
 332         if (!(prev_file->flags & FLAG_HLINK_DONE)) {
 333                 /* Is the previous link being transferred? */
 334                 if (prev_file->flags & FLAG_FILE_SENT) {
 335                         /* Add ourselves to the list of files that will be
 336                          * updated when the transfer completes, and mark
 337                          * ourself as waiting for the transfer. */
 338                         F_HL_PREV(file) = F_HL_PREV(prev_file);
 339                         F_HL_PREV(prev_file) = ndx;
 340                         file->flags |= FLAG_FILE_SENT;
 341                         return 1;
 342                 }
 343                 return 0;
 344         }
 345
 346         /* There is a finished file to link with! */
 347         if (!(prev_file->flags & FLAG_HLINK_FIRST)) {
 348                 /* The previous previous will be marked with FIRST. */
 349                 prev_ndx = F_HL_PREV(prev_file);
 350                 prev_file = cur_flist->files[prev_ndx];
 351                 /* Update our previous pointer to point to the first. */
 352                 F_HL_PREV(file) = prev_ndx;
 353         }
 354         alt_dest = F_HL_PREV(prev_file); /* alternate value when DONE && FIRST */
 355         if (alt_dest >= 0 && dry_run) {
 356                 pathjoin(prev_name, MAXPATHLEN, basis_dir[alt_dest],
 357                          f_name(prev_file, NULL));
 358                 f_name(prev_file, altbuf);
 359                 realname = altbuf;
 360         } else {
 361                 f_name(prev_file, prev_name);
 362                 realname = prev_name;
 363         }
 364
 365         if (link_stat(prev_name, &prev_st, 0) < 0) {
 366                 rsyserr(FERROR, errno, "stat %s failed",
 367                         full_fname(prev_name));
 368                 return -1;
 369         }
 370
 371         if (statret < 0 && basis_dir[0] != NULL) {
 372                 /* If we match an alt-dest item, we don't output this as a change. */
 373                 char cmpbuf[MAXPATHLEN];
 374                 statx alt_sx;
 375                 int j = 0;
 376 #ifdef SUPPORT_ACLS
 377                 alt_sx.acc_acl = alt_sx.def_acl = NULL;
 378 #endif
 379                 do {
 380                         pathjoin(cmpbuf, MAXPATHLEN, basis_dir[j], fname);
 381                         if (link_stat(cmpbuf, &alt_sx.st, 0) < 0)
 382                                 continue;
 383                         if (link_dest) {
 384                                 if (prev_st.st_dev != alt_sx.st.st_dev
 385                                  || prev_st.st_ino != alt_sx.st.st_ino)
 386                                         continue;
 387                                 statret = 1;
 388                                 if (verbose < 2 || !stdout_format_has_i) {
 389                                         itemizing = 0;
 390                                         code = FNONE;
 391                                         if (verbose > 1 && maybe_ATTRS_REPORT)
 392                                                 rprintf(FCLIENT, "%s is uptodate\n", fname);
 393                                 }
 394                                 break;
 395                         }
 396                         if (!unchanged_file(cmpbuf, file, &alt_sx.st))
 397                                 continue;
 398                         statret = 1;
 399                         if (unchanged_attrs(cmpbuf, file, &alt_sx))
 400                                 break;
 401                 } while (basis_dir[++j] != NULL);
 402                 if (statret == 1) {
 403                         sxp->st = alt_sx.st;
 404 #ifdef SUPPORT_ACLS
 405                         if (preserve_acls && !S_ISLNK(file->mode)) {
 406                                 if (!ACL_READY(*sxp))
 407                                         get_acl(cmpbuf, sxp);
 408                                 else {
 409                                         sxp->acc_acl = alt_sx.acc_acl;
 410                                         sxp->def_acl = alt_sx.def_acl;
 411                                 }
 412                         }
 413 #endif
 414                 }
 415 #ifdef SUPPORT_ACLS
 416                 else if (preserve_acls)
 417                         free_acl(&alt_sx);
 418 #endif
 419         }
 420
 421         if (maybe_hard_link(file, ndx, fname, statret, sxp, prev_name, &prev_st,
 422                             realname, itemizing, code) < 0)
 423                 return -1;
 424
 425         if (remove_source_files == 1 && do_xfers)
 426                 send_msg_int(MSG_SUCCESS, ndx);
 427
 428         return 1;
 429 }
 430
 431 int hard_link_one(struct file_struct *file, const char *fname,
 432                   const char *oldname, int terse)
 433 {
 434         if (do_link(oldname, fname) < 0) {
 435                 enum logcode code;
 436                 if (terse) {
 437                         if (!verbose)
 438                                 return -1;
 439                         code = FINFO;
 440                 } else
 441                         code = FERROR;
 442                 rsyserr(code, errno, "link %s => %s failed",
 443                         full_fname(fname), oldname);
 444                 return 0;
 445         }
 446
 447         file->flags |= FLAG_HLINK_DONE;
 448
 449         return 1;
 450 }
 451
 452 void finish_hard_link(struct file_struct *file, const char *fname,
 453                       STRUCT_STAT *stp, int itemizing, enum logcode code,
 454                       int alt_dest)
 455 {
 456         statx prev_sx;
 457         STRUCT_STAT st;
 458         char alt_name[MAXPATHLEN], *prev_name;
 459         const char *our_name;
 460         int prev_statret, ndx, prev_ndx = F_HL_PREV(file);
 461
 462         if (stp == NULL && prev_ndx >= 0) {
 463                 if (link_stat(fname, &st, 0) < 0) {
 464                         rsyserr(FERROR, errno, "stat %s failed",
 465                                 full_fname(fname));
 466                         return;
 467                 }
 468                 stp = &st;
 469         }
 470
 471         /* FIRST combined with DONE means we were the first to get done. */
 472         file->flags |= FLAG_HLINK_FIRST | FLAG_HLINK_DONE;
 473         F_HL_PREV(file) = alt_dest;
 474         if (alt_dest >= 0 && dry_run) {
 475                 pathjoin(alt_name, MAXPATHLEN, basis_dir[alt_dest],
 476                          f_name(file, NULL));
 477                 our_name = alt_name;
 478         } else
 479                 our_name = fname;
 480
 481 #ifdef SUPPORT_ACLS
 482         prev_sx.acc_acl = prev_sx.def_acl = NULL;
 483 #endif
 484
 485         while ((ndx = prev_ndx) >= 0) {
 486                 int val;
 487                 file = cur_flist->files[ndx];
 488                 file->flags = (file->flags & ~FLAG_HLINK_FIRST) | FLAG_HLINK_DONE;
 489                 prev_ndx = F_HL_PREV(file);
 490                 prev_name = f_name(file, NULL);
 491                 prev_statret = link_stat(prev_name, &prev_sx.st, 0);
 492                 val = maybe_hard_link(file, ndx, prev_name, prev_statret, &prev_sx,
 493                                       our_name, stp, fname, itemizing, code);
 494 #ifdef SUPPORT_ACLS
 495                 if (preserve_acls)
 496                         free_acl(&prev_sx);
 497 #endif
 498                 if (val < 0)
 499                         continue;
 500                 if (remove_source_files == 1 && do_xfers)
 501                         send_msg_int(MSG_SUCCESS, ndx);
 502         }
 503 }
 504 #endif