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