generator.c

   1 /* -*- c-file-style: "linux" -*-
   2
   3    rsync -- fast file replication program
   4
   5    Copyright (C) 1996-2000 by Andrew Tridgell
   6    Copyright (C) Paul Mackerras 1996
   7    Copyright (C) 2002 by Martin Pool <mbp@samba.org>
   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
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include "rsync.h"
  25
  26 extern int verbose;
  27 extern int dry_run;
  28 extern int relative_paths;
  29 extern int keep_dirlinks;
  30 extern int preserve_links;
  31 extern int am_root;
  32 extern int preserve_devices;
  33 extern int preserve_hard_links;
  34 extern int preserve_perms;
  35 extern int preserve_uid;
  36 extern int preserve_gid;
  37 extern int update_only;
  38 extern int opt_ignore_existing;
  39 extern int csum_length;
  40 extern int ignore_times;
  41 extern int size_only;
  42 extern int io_timeout;
  43 extern int protocol_version;
  44 extern int always_checksum;
  45 extern char *compare_dest;
  46 extern int link_dest;
  47 extern int whole_file;
  48 extern int local_server;
  49 extern int list_only;
  50 extern int read_batch;
  51 extern int only_existing;
  52 extern int orig_umask;
  53 extern int safe_symlinks;
  54 extern unsigned int block_size;
  55
  56 extern struct exclude_list_struct server_exclude_list;
  57
  58
  59 /* choose whether to skip a particular file */
  60 static int skip_file(char *fname, struct file_struct *file, STRUCT_STAT *st)
  61 {
  62         if (st->st_size != file->length)
  63                 return 0;
  64         if (link_dest) {
  65                 if (preserve_perms
  66                     && (st->st_mode & CHMOD_BITS) != (file->mode & CHMOD_BITS))
  67                         return 0;
  68
  69                 if (am_root && preserve_uid && st->st_uid != file->uid)
  70                         return 0;
  71
  72                 if (preserve_gid && file->gid != GID_NONE
  73                     && st->st_gid != file->gid)
  74                         return 0;
  75         }
  76
  77         /* if always checksum is set then we use the checksum instead
  78            of the file time to determine whether to sync */
  79         if (always_checksum && S_ISREG(st->st_mode)) {
  80                 char sum[MD4_SUM_LENGTH];
  81                 char fnamecmpdest[MAXPATHLEN];
  82
  83                 if (compare_dest != NULL) {
  84                         if (access(fname, 0) != 0) {
  85                                 pathjoin(fnamecmpdest, sizeof fnamecmpdest,
  86                                          compare_dest, fname);
  87                                 fname = fnamecmpdest;
  88                         }
  89                 }
  90                 file_checksum(fname,sum,st->st_size);
  91                 return memcmp(sum, file->u.sum, protocol_version < 21 ? 2
  92                                                         : MD4_SUM_LENGTH) == 0;
  93         }
  94
  95         if (size_only)
  96                 return 1;
  97
  98         if (ignore_times)
  99                 return 0;
 100
 101         return cmp_modtime(st->st_mtime, file->modtime) == 0;
 102 }
 103
 104
 105 /*
 106  * NULL sum_struct means we have no checksums
 107  */
 108 void write_sum_head(int f, struct sum_struct *sum)
 109 {
 110         static struct sum_struct null_sum;
 111
 112         if (sum == NULL)
 113                 sum = &null_sum;
 114
 115         write_int(f, sum->count);
 116         write_int(f, sum->blength);
 117         if (protocol_version >= 27)
 118                 write_int(f, sum->s2length);
 119         write_int(f, sum->remainder);
 120 }
 121
 122 /*
 123  * set (initialize) the size entries in the per-file sum_struct
 124  * calculating dynamic block and checksum sizes.
 125  *
 126  * This is only called from generate_and_send_sums() but is a separate
 127  * function to encapsulate the logic.
 128  *
 129  * The block size is a rounded square root of file length.
 130  *
 131  * The checksum size is determined according to:
 132  *     blocksum_bits = BLOCKSUM_EXP + 2*log2(file_len) - log2(block_len)
 133  * provided by Donovan Baarda which gives a probability of rsync
 134  * algorithm corrupting data and falling back using the whole md4
 135  * checksums.
 136  *
 137  * This might be made one of several selectable heuristics.
 138  */
 139
 140 static void sum_sizes_sqroot(struct sum_struct *sum, uint64 len)
 141 {
 142         unsigned int blength;
 143         int s2length;
 144         uint32 c;
 145         uint64 l;
 146
 147         if (block_size) {
 148                 blength = block_size;
 149         } else if (len <= BLOCK_SIZE * BLOCK_SIZE) {
 150                 blength = BLOCK_SIZE;
 151         } else {
 152                 l = len;
 153                 c = 1;
 154                 while (l >>= 2) {
 155                         c <<= 1;
 156                 }
 157                 blength = 0;
 158                 do {
 159                         blength |= c;
 160                         if (len < (uint64)blength * blength)
 161                                 blength &= ~c;
 162                         c >>= 1;
 163                 } while (c >= 8);       /* round to multiple of 8 */
 164                 blength = MAX(blength, BLOCK_SIZE);
 165         }
 166
 167         if (protocol_version < 27) {
 168                 s2length = csum_length;
 169         } else if (csum_length == SUM_LENGTH) {
 170                 s2length = SUM_LENGTH;
 171         } else {
 172                 int b = BLOCKSUM_BIAS;
 173                 l = len;
 174                 while (l >>= 1) {
 175                         b += 2;
 176                 }
 177                 c = blength;
 178                 while (c >>= 1 && b) {
 179                         b--;
 180                 }
 181                 s2length = (b + 1 - 32 + 7) / 8; /* add a bit,
 182                                                   * subtract rollsum,
 183                                                   * round up
 184                                                   *    --optimize in compiler--
 185                                                   */
 186                 s2length = MAX(s2length, csum_length);
 187                 s2length = MIN(s2length, SUM_LENGTH);
 188         }
 189
 190         sum->flength    = len;
 191         sum->blength    = blength;
 192         sum->s2length   = s2length;
 193         sum->count      = (len + (blength - 1)) / blength;
 194         sum->remainder  = (len % blength);
 195
 196         if (sum->count && verbose > 2) {
 197                 rprintf(FINFO, "count=%.0f rem=%u blength=%u s2length=%d flength=%.0f\n",
 198                         (double)sum->count, sum->remainder, sum->blength,
 199                         sum->s2length, (double)sum->flength);
 200         }
 201 }
 202
 203
 204 /*
 205  * Generate and send a stream of signatures/checksums that describe a buffer
 206  *
 207  * Generate approximately one checksum every block_len bytes.
 208  */
 209 static void generate_and_send_sums(struct map_struct *buf, OFF_T len, int f_out)
 210 {
 211         size_t i;
 212         struct sum_struct sum;
 213         OFF_T offset = 0;
 214
 215         sum_sizes_sqroot(&sum, len);
 216
 217         write_sum_head(f_out, &sum);
 218
 219         for (i = 0; i < sum.count; i++) {
 220                 unsigned int n1 = MIN(len, sum.blength);
 221                 char *map = map_ptr(buf, offset, n1);
 222                 uint32 sum1 = get_checksum1(map, n1);
 223                 char sum2[SUM_LENGTH];
 224
 225                 get_checksum2(map, n1, sum2);
 226
 227                 if (verbose > 3) {
 228                         rprintf(FINFO,
 229                                 "chunk[%.0f] offset=%.0f len=%u sum1=%08lx\n",
 230                                 (double)i, (double)offset, n1,
 231                                 (unsigned long)sum1);
 232                 }
 233                 write_int(f_out, sum1);
 234                 write_buf(f_out, sum2, sum.s2length);
 235                 len -= n1;
 236                 offset += n1;
 237         }
 238 }
 239
 240
 241
 242 /*
 243  * Acts on file number @p i from @p flist, whose name is @p fname.
 244  *
 245  * First fixes up permissions, then generates checksums for the file.
 246  *
 247  * @note This comment was added later by mbp who was trying to work it
 248  * out.  It might be wrong.
 249  */
 250 static void recv_generator(char *fname, struct file_struct *file, int i,
 251                            int f_out)
 252 {
 253         int fd;
 254         STRUCT_STAT st;
 255         struct map_struct *mapbuf;
 256         int statret;
 257         char *fnamecmp;
 258         char fnamecmpbuf[MAXPATHLEN];
 259
 260         if (list_only)
 261                 return;
 262
 263         if (verbose > 2)
 264                 rprintf(FINFO,"recv_generator(%s,%d)\n",fname,i);
 265
 266         if (server_exclude_list.head
 267             && check_exclude(&server_exclude_list, fname,
 268                              S_ISDIR(file->mode)) < 0) {
 269                 if (verbose) {
 270                         rprintf(FINFO, "skipping server-excluded file \"%s\"\n",
 271                                 fname);
 272                 }
 273                 return;
 274         }
 275
 276         statret = link_stat(fname, &st, keep_dirlinks && S_ISDIR(file->mode));
 277
 278         if (only_existing && statret == -1 && errno == ENOENT) {
 279                 /* we only want to update existing files */
 280                 if (verbose > 1)
 281                         rprintf(FINFO, "not creating new file \"%s\"\n", fname);
 282                 return;
 283         }
 284
 285         if (statret == 0 &&
 286             !preserve_perms &&
 287             (S_ISDIR(st.st_mode) == S_ISDIR(file->mode))) {
 288                 /* if the file exists already and we aren't perserving
 289                  * permissions then act as though the remote end sent
 290                  * us the file permissions we already have */
 291                 file->mode = (file->mode & ~CHMOD_BITS)
 292                            | (st.st_mode & CHMOD_BITS);
 293         }
 294
 295         if (S_ISDIR(file->mode)) {
 296                 /* The file to be received is a directory, so we need
 297                  * to prepare appropriately.  If there is already a
 298                  * file of that name and it is *not* a directory, then
 299                  * we need to delete it.  If it doesn't exist, then
 300                  * recursively create it. */
 301
 302                 if (dry_run)
 303                         return; /* TODO: causes inaccuracies -- fix */
 304                 if (statret == 0 && !S_ISDIR(st.st_mode)) {
 305                         if (robust_unlink(fname) != 0) {
 306                                 rsyserr(FERROR, errno,
 307                                         "recv_generator: unlink %s to make room for directory",
 308                                         full_fname(fname));
 309                                 return;
 310                         }
 311                         statret = -1;
 312                 }
 313                 if (statret != 0 && do_mkdir(fname,file->mode) != 0 && errno != EEXIST) {
 314                         if (!(relative_paths && errno == ENOENT
 315                             && create_directory_path(fname, orig_umask) == 0
 316                             && do_mkdir(fname, file->mode) == 0)) {
 317                                 rsyserr(FERROR, errno,
 318                                         "recv_generator: mkdir %s failed",
 319                                         full_fname(fname));
 320                         }
 321                 }
 322                 /* f_out is set to -1 when doing final directory-permission
 323                  * and modification-time repair. */
 324                 if (set_perms(fname, file, statret ? NULL : &st, 0)
 325                     && verbose && f_out != -1)
 326                         rprintf(FINFO,"%s/\n",fname);
 327                 return;
 328         }
 329
 330         if (read_batch)
 331                 return;
 332
 333         if (preserve_links && S_ISLNK(file->mode)) {
 334 #if SUPPORT_LINKS
 335                 char lnk[MAXPATHLEN];
 336                 int l;
 337
 338                 if (safe_symlinks && unsafe_symlink(file->u.link, fname)) {
 339                         if (verbose) {
 340                                 rprintf(FINFO, "ignoring unsafe symlink %s -> \"%s\"\n",
 341                                         full_fname(fname), file->u.link);
 342                         }
 343                         return;
 344                 }
 345                 if (statret == 0) {
 346                         l = readlink(fname,lnk,MAXPATHLEN-1);
 347                         if (l > 0) {
 348                                 lnk[l] = 0;
 349                                 /* A link already pointing to the
 350                                  * right place -- no further action
 351                                  * required. */
 352                                 if (strcmp(lnk,file->u.link) == 0) {
 353                                         set_perms(fname, file, &st,
 354                                                   PERMS_REPORT);
 355                                         return;
 356                                 }
 357                         }
 358                         /* Not a symlink, so delete whatever's
 359                          * already there and put a new symlink
 360                          * in place. */
 361                         delete_file(fname);
 362                 }
 363                 if (do_symlink(file->u.link,fname) != 0) {
 364                         rsyserr(FERROR, errno, "symlink %s -> \"%s\" failed",
 365                                 full_fname(fname), file->u.link);
 366                 } else {
 367                         set_perms(fname,file,NULL,0);
 368                         if (verbose) {
 369                                 rprintf(FINFO,"%s -> %s\n", fname,file->u.link);
 370                         }
 371                 }
 372 #endif
 373                 return;
 374         }
 375
 376 #ifdef HAVE_MKNOD
 377         if (am_root && preserve_devices && IS_DEVICE(file->mode)) {
 378                 if (statret != 0 ||
 379                     st.st_mode != file->mode ||
 380                     st.st_rdev != file->u.rdev) {
 381                         delete_file(fname);
 382                         if (verbose > 2) {
 383                                 rprintf(FINFO,"mknod(%s,0%o,0x%x)\n",
 384                                         fname,(int)file->mode,(int)file->u.rdev);
 385                         }
 386                         if (do_mknod(fname,file->mode,file->u.rdev) != 0) {
 387                                 rsyserr(FERROR, errno, "mknod %s failed",
 388                                         full_fname(fname));
 389                         } else {
 390                                 set_perms(fname,file,NULL,0);
 391                                 if (verbose)
 392                                         rprintf(FINFO,"%s\n",fname);
 393                         }
 394                 } else {
 395                         set_perms(fname, file, &st, PERMS_REPORT);
 396                 }
 397                 return;
 398         }
 399 #endif
 400
 401         if (preserve_hard_links && hard_link_check(file, HL_CHECK_MASTER))
 402                 return;
 403
 404         if (!S_ISREG(file->mode)) {
 405                 rprintf(FINFO, "skipping non-regular file \"%s\"\n",fname);
 406                 return;
 407         }
 408
 409         fnamecmp = fname;
 410
 411         if (statret == -1 && compare_dest != NULL) {
 412                 /* try the file at compare_dest instead */
 413                 int saveerrno = errno;
 414                 pathjoin(fnamecmpbuf, sizeof fnamecmpbuf, compare_dest, fname);
 415                 statret = link_stat(fnamecmpbuf, &st, 0);
 416                 if (!S_ISREG(st.st_mode))
 417                         statret = -1;
 418                 if (statret == -1)
 419                         errno = saveerrno;
 420 #if HAVE_LINK
 421                 else if (link_dest && !dry_run) {
 422                         if (do_link(fnamecmpbuf, fname) != 0) {
 423                                 if (verbose > 0) {
 424                                         rsyserr(FINFO, errno, "link %s => %s",
 425                                                 fnamecmpbuf, fname);
 426                                 }
 427                         }
 428                         fnamecmp = fnamecmpbuf;
 429                 }
 430 #endif
 431                 else
 432                         fnamecmp = fnamecmpbuf;
 433         }
 434
 435         if (statret == -1) {
 436                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 437                         return;
 438                 if (errno == ENOENT) {
 439                         write_int(f_out,i);
 440                         if (!dry_run)
 441                                 write_sum_head(f_out, NULL);
 442                 } else if (verbose > 1) {
 443                         rsyserr(FERROR, errno,
 444                                 "recv_generator: failed to open %s",
 445                                 full_fname(fname));
 446                 }
 447                 return;
 448         }
 449
 450         if (!S_ISREG(st.st_mode)) {
 451                 if (delete_file(fname) != 0) {
 452                         return;
 453                 }
 454
 455                 /* now pretend the file didn't exist */
 456                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 457                         return;
 458                 write_int(f_out,i);
 459                 if (!dry_run)
 460                         write_sum_head(f_out, NULL);
 461                 return;
 462         }
 463
 464         if (opt_ignore_existing && fnamecmp == fname) {
 465                 if (verbose > 1)
 466                         rprintf(FINFO,"%s exists\n",fname);
 467                 return;
 468         }
 469
 470         if (update_only && fnamecmp == fname
 471             && cmp_modtime(st.st_mtime, file->modtime) > 0) {
 472                 if (verbose > 1)
 473                         rprintf(FINFO,"%s is newer\n",fname);
 474                 return;
 475         }
 476
 477         if (skip_file(fname, file, &st)) {
 478                 if (fnamecmp == fname)
 479                         set_perms(fname, file, &st, PERMS_REPORT);
 480                 return;
 481         }
 482
 483         if (dry_run) {
 484                 write_int(f_out,i);
 485                 return;
 486         }
 487
 488         if (whole_file > 0) {
 489                 write_int(f_out,i);
 490                 write_sum_head(f_out, NULL);
 491                 return;
 492         }
 493
 494         /* open the file */
 495         fd = do_open(fnamecmp, O_RDONLY, 0);
 496
 497         if (fd == -1) {
 498                 rsyserr(FERROR, errno, "failed to open %s, continuing",
 499                         full_fname(fnamecmp));
 500                 /* pretend the file didn't exist */
 501                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 502                         return;
 503                 write_int(f_out,i);
 504                 write_sum_head(f_out, NULL);
 505                 return;
 506         }
 507
 508         if (st.st_size > 0)
 509                 mapbuf = map_file(fd,st.st_size);
 510         else
 511                 mapbuf = NULL;
 512
 513         if (verbose > 3) {
 514                 rprintf(FINFO,"gen mapped %s of size %.0f\n", fnamecmp,
 515                         (double)st.st_size);
 516         }
 517
 518         if (verbose > 2)
 519                 rprintf(FINFO, "generating and sending sums for %d\n", i);
 520
 521         write_int(f_out,i);
 522         generate_and_send_sums(mapbuf, st.st_size, f_out);
 523
 524         close(fd);
 525         if (mapbuf)
 526                 unmap_file(mapbuf);
 527 }
 528
 529
 530 void generate_files(int f_out, struct file_list *flist, char *local_name)
 531 {
 532         int i;
 533         int phase = 0;
 534         char fbuf[MAXPATHLEN];
 535
 536         if (verbose > 2) {
 537                 rprintf(FINFO, "generator starting pid=%ld count=%d\n",
 538                         (long)getpid(), flist->count);
 539         }
 540
 541         if (verbose >= 2) {
 542                 rprintf(FINFO,
 543                         whole_file > 0
 544                         ? "delta-transmission disabled for local transfer or --whole-file\n"
 545                         : "delta transmission enabled\n");
 546         }
 547
 548         /* we expect to just sit around now, so don't exit on a
 549            timeout. If we really get a timeout then the other process should
 550            exit */
 551         io_timeout = 0;
 552
 553         for (i = 0; i < flist->count; i++) {
 554                 struct file_struct *file = flist->files[i];
 555                 struct file_struct copy;
 556
 557                 if (!file->basename)
 558                         continue;
 559                 /* we need to ensure that any directories we create have writeable
 560                    permissions initially so that we can create the files within
 561                    them. This is then fixed after the files are transferred */
 562                 if (!am_root && S_ISDIR(file->mode) && !(file->mode & S_IWUSR)) {
 563                         copy = *file;
 564                         /* XXX: Could this be causing a problem on SCO?  Perhaps their
 565                          * handling of permissions is strange? */
 566                         copy.mode |= S_IWUSR; /* user write */
 567                         file = &copy;
 568                 }
 569
 570                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 571                                file, i, f_out);
 572         }
 573
 574         phase++;
 575         csum_length = SUM_LENGTH;
 576         ignore_times = 1;
 577
 578         if (verbose > 2)
 579                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 580
 581         write_int(f_out, -1);
 582
 583         /* files can cycle through the system more than once
 584          * to catch initial checksum errors */
 585         while ((i = get_redo_num()) != -1) {
 586                 struct file_struct *file = flist->files[i];
 587                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 588                                file, i, f_out);
 589         }
 590
 591         phase++;
 592         if (verbose > 2)
 593                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 594
 595         write_int(f_out, -1);
 596
 597         if (preserve_hard_links)
 598                 do_hard_links();
 599
 600         /* now we need to fix any directory permissions that were
 601          * modified during the transfer */
 602         for (i = 0; i < flist->count; i++) {
 603                 struct file_struct *file = flist->files[i];
 604                 if (!file->basename || !S_ISDIR(file->mode))
 605                         continue;
 606                 recv_generator(local_name ? local_name : f_name(file),
 607                                file, i, -1);
 608         }
 609
 610         if (verbose > 2)
 611                 rprintf(FINFO,"generate_files finished\n");
 612 }