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 read_batch;
  50 extern int write_batch;
  51 extern int list_only;
  52 extern int only_existing;
  53 extern int orig_umask;
  54 extern int safe_symlinks;
  55 extern unsigned int block_size;
  56
  57 extern struct exclude_list_struct server_exclude_list;
  58
  59
  60 /* choose whether to skip a particular file */
  61 static int skip_file(char *fname, struct file_struct *file, STRUCT_STAT *st)
  62 {
  63         if (st->st_size != file->length)
  64                 return 0;
  65         if (link_dest) {
  66                 if (preserve_perms
  67                     && (st->st_mode & CHMOD_BITS) != (file->mode & CHMOD_BITS))
  68                         return 0;
  69
  70                 if (am_root && preserve_uid && st->st_uid != file->uid)
  71                         return 0;
  72
  73                 if (preserve_gid && file->gid != GID_NONE
  74                     && st->st_gid != file->gid)
  75                         return 0;
  76         }
  77
  78         /* if always checksum is set then we use the checksum instead
  79            of the file time to determine whether to sync */
  80         if (always_checksum && S_ISREG(st->st_mode)) {
  81                 char sum[MD4_SUM_LENGTH];
  82                 char fnamecmpdest[MAXPATHLEN];
  83
  84                 if (compare_dest != NULL) {
  85                         if (access(fname, 0) != 0) {
  86                                 pathjoin(fnamecmpdest, sizeof fnamecmpdest,
  87                                          compare_dest, fname);
  88                                 fname = fnamecmpdest;
  89                         }
  90                 }
  91                 file_checksum(fname,sum,st->st_size);
  92                 return memcmp(sum, file->u.sum, protocol_version < 21 ? 2
  93                                                         : MD4_SUM_LENGTH) == 0;
  94         }
  95
  96         if (size_only)
  97                 return 1;
  98
  99         if (ignore_times)
 100                 return 0;
 101
 102         return cmp_modtime(st->st_mtime, file->modtime) == 0;
 103 }
 104
 105
 106 /*
 107  * NULL sum_struct means we have no checksums
 108  */
 109 void write_sum_head(int f, struct sum_struct *sum)
 110 {
 111         static struct sum_struct null_sum;
 112
 113         if (sum == NULL)
 114                 sum = &null_sum;
 115
 116         write_int(f, sum->count);
 117         write_int(f, sum->blength);
 118         if (protocol_version >= 27)
 119                 write_int(f, sum->s2length);
 120         write_int(f, sum->remainder);
 121 }
 122
 123 /*
 124  * set (initialize) the size entries in the per-file sum_struct
 125  * calculating dynamic block and checksum sizes.
 126  *
 127  * This is only called from generate_and_send_sums() but is a separate
 128  * function to encapsulate the logic.
 129  *
 130  * The block size is a rounded square root of file length.
 131  *
 132  * The checksum size is determined according to:
 133  *     blocksum_bits = BLOCKSUM_EXP + 2*log2(file_len) - log2(block_len)
 134  * provided by Donovan Baarda which gives a probability of rsync
 135  * algorithm corrupting data and falling back using the whole md4
 136  * checksums.
 137  *
 138  * This might be made one of several selectable heuristics.
 139  */
 140
 141 static void sum_sizes_sqroot(struct sum_struct *sum, uint64 len)
 142 {
 143         unsigned int blength;
 144         int s2length;
 145         uint32 c;
 146         uint64 l;
 147
 148         if (block_size) {
 149                 blength = block_size;
 150         } else if (len <= BLOCK_SIZE * BLOCK_SIZE) {
 151                 blength = BLOCK_SIZE;
 152         } else {
 153                 l = len;
 154                 c = 1;
 155                 while (l >>= 2) {
 156                         c <<= 1;
 157                 }
 158                 blength = 0;
 159                 do {
 160                         blength |= c;
 161                         if (len < (uint64)blength * blength)
 162                                 blength &= ~c;
 163                         c >>= 1;
 164                 } while (c >= 8);       /* round to multiple of 8 */
 165                 blength = MAX(blength, BLOCK_SIZE);
 166         }
 167
 168         if (protocol_version < 27) {
 169                 s2length = csum_length;
 170         } else if (csum_length == SUM_LENGTH) {
 171                 s2length = SUM_LENGTH;
 172         } else {
 173                 int b = BLOCKSUM_BIAS;
 174                 l = len;
 175                 while (l >>= 1) {
 176                         b += 2;
 177                 }
 178                 c = blength;
 179                 while (c >>= 1 && b) {
 180                         b--;
 181                 }
 182                 s2length = (b + 1 - 32 + 7) / 8; /* add a bit,
 183                                                   * subtract rollsum,
 184                                                   * round up
 185                                                   *    --optimize in compiler--
 186                                                   */
 187                 s2length = MAX(s2length, csum_length);
 188                 s2length = MIN(s2length, SUM_LENGTH);
 189         }
 190
 191         sum->flength    = len;
 192         sum->blength    = blength;
 193         sum->s2length   = s2length;
 194         sum->count      = (len + (blength - 1)) / blength;
 195         sum->remainder  = (len % blength);
 196
 197         if (sum->count && verbose > 2) {
 198                 rprintf(FINFO, "count=%.0f rem=%u blength=%u s2length=%d flength=%.0f\n",
 199                         (double)sum->count, sum->remainder, sum->blength,
 200                         sum->s2length, (double)sum->flength);
 201         }
 202 }
 203
 204 /**
 205  * Perhaps we want to just send an empty checksum set for this file,
 206  * which will force the whole thing to be literally transferred.
 207  *
 208  * When do we do this?  If the user's explicitly said they
 209  * want the whole thing, or if { they haven't explicitly
 210  * requested a delta, and it's local but not batch mode.}
 211  *
 212  * Whew. */
 213 static BOOL disable_deltas_p(void)
 214 {
 215         if (whole_file > 0)
 216                 return True;
 217         if (whole_file == 0 || write_batch || read_batch)
 218                 return False;
 219         return local_server;
 220 }
 221
 222
 223 /*
 224  * Generate and send a stream of signatures/checksums that describe a buffer
 225  *
 226  * Generate approximately one checksum every block_len bytes.
 227  */
 228 static void generate_and_send_sums(struct map_struct *buf, size_t len, int f_out)
 229 {
 230         size_t i;
 231         struct sum_struct sum;
 232         OFF_T offset = 0;
 233
 234         sum_sizes_sqroot(&sum, len);
 235
 236         write_sum_head(f_out, &sum);
 237
 238         for (i = 0; i < sum.count; i++) {
 239                 unsigned int n1 = MIN(len, sum.blength);
 240                 char *map = map_ptr(buf, offset, n1);
 241                 uint32 sum1 = get_checksum1(map, n1);
 242                 char sum2[SUM_LENGTH];
 243
 244                 get_checksum2(map, n1, sum2);
 245
 246                 if (verbose > 3) {
 247                         rprintf(FINFO,
 248                                 "chunk[%.0f] offset=%.0f len=%u sum1=%08lx\n",
 249                                 (double)i, (double)offset, n1,
 250                                 (unsigned long)sum1);
 251                 }
 252                 write_int(f_out, sum1);
 253                 write_buf(f_out, sum2, sum.s2length);
 254                 len -= n1;
 255                 offset += n1;
 256         }
 257 }
 258
 259
 260
 261 /**
 262  * Acts on file number @p i from @p flist, whose name is @p fname.
 263  *
 264  * First fixes up permissions, then generates checksums for the file.
 265  *
 266  * @note This comment was added later by mbp who was trying to work it
 267  * out.  It might be wrong.
 268  **/
 269 void recv_generator(char *fname, struct file_struct *file, int i, int f_out)
 270 {
 271         int fd;
 272         STRUCT_STAT st;
 273         struct map_struct *mapbuf;
 274         int statret;
 275         char *fnamecmp;
 276         char fnamecmpbuf[MAXPATHLEN];
 277
 278         if (list_only)
 279                 return;
 280
 281         if (verbose > 2)
 282                 rprintf(FINFO,"recv_generator(%s,%d)\n",fname,i);
 283
 284         if (server_exclude_list.head
 285             && check_exclude(&server_exclude_list, fname,
 286                              S_ISDIR(file->mode)) < 0) {
 287                 if (verbose) {
 288                         rprintf(FINFO, "skipping server-excluded file \"%s\"\n",
 289                                 fname);
 290                 }
 291                 return;
 292         }
 293
 294         statret = link_stat(fname, &st, keep_dirlinks && S_ISDIR(file->mode));
 295
 296         if (only_existing && statret == -1 && errno == ENOENT) {
 297                 /* we only want to update existing files */
 298                 if (verbose > 1)
 299                         rprintf(FINFO, "not creating new file \"%s\"\n", fname);
 300                 return;
 301         }
 302
 303         if (statret == 0 &&
 304             !preserve_perms &&
 305             (S_ISDIR(st.st_mode) == S_ISDIR(file->mode))) {
 306                 /* if the file exists already and we aren't perserving
 307                  * permissions then act as though the remote end sent
 308                  * us the file permissions we already have */
 309                 file->mode = (file->mode & ~CHMOD_BITS)
 310                            | (st.st_mode & CHMOD_BITS);
 311         }
 312
 313         if (S_ISDIR(file->mode)) {
 314                 /* The file to be received is a directory, so we need
 315                  * to prepare appropriately.  If there is already a
 316                  * file of that name and it is *not* a directory, then
 317                  * we need to delete it.  If it doesn't exist, then
 318                  * recursively create it. */
 319
 320                 if (dry_run)
 321                         return; /* TODO: causes inaccuracies -- fix */
 322                 if (statret == 0 && !S_ISDIR(st.st_mode)) {
 323                         if (robust_unlink(fname) != 0) {
 324                                 rsyserr(FERROR, errno,
 325                                         "recv_generator: unlink %s to make room for directory",
 326                                         full_fname(fname));
 327                                 return;
 328                         }
 329                         statret = -1;
 330                 }
 331                 if (statret != 0 && do_mkdir(fname,file->mode) != 0 && errno != EEXIST) {
 332                         if (!(relative_paths && errno == ENOENT
 333                             && create_directory_path(fname, orig_umask) == 0
 334                             && do_mkdir(fname, file->mode) == 0)) {
 335                                 rsyserr(FERROR, errno,
 336                                         "recv_generator: mkdir %s failed",
 337                                         full_fname(fname));
 338                         }
 339                 }
 340                 /* f_out is set to -1 when doing final directory-permission
 341                  * and modification-time repair. */
 342                 if (set_perms(fname, file, statret ? NULL : &st, 0)
 343                     && verbose && f_out != -1)
 344                         rprintf(FINFO,"%s/\n",fname);
 345                 return;
 346         }
 347
 348         if (preserve_links && S_ISLNK(file->mode)) {
 349 #if SUPPORT_LINKS
 350                 char lnk[MAXPATHLEN];
 351                 int l;
 352
 353                 if (safe_symlinks && unsafe_symlink(file->u.link, fname)) {
 354                         if (verbose) {
 355                                 rprintf(FINFO, "ignoring unsafe symlink %s -> \"%s\"\n",
 356                                         full_fname(fname), file->u.link);
 357                         }
 358                         return;
 359                 }
 360                 if (statret == 0) {
 361                         l = readlink(fname,lnk,MAXPATHLEN-1);
 362                         if (l > 0) {
 363                                 lnk[l] = 0;
 364                                 /* A link already pointing to the
 365                                  * right place -- no further action
 366                                  * required. */
 367                                 if (strcmp(lnk,file->u.link) == 0) {
 368                                         set_perms(fname, file, &st,
 369                                                   PERMS_REPORT);
 370                                         return;
 371                                 }
 372                         }
 373                         /* Not a symlink, so delete whatever's
 374                          * already there and put a new symlink
 375                          * in place. */
 376                         delete_file(fname);
 377                 }
 378                 if (do_symlink(file->u.link,fname) != 0) {
 379                         rsyserr(FERROR, errno, "symlink %s -> \"%s\" failed",
 380                                 full_fname(fname), file->u.link);
 381                 } else {
 382                         set_perms(fname,file,NULL,0);
 383                         if (verbose) {
 384                                 rprintf(FINFO,"%s -> %s\n", fname,file->u.link);
 385                         }
 386                 }
 387 #endif
 388                 return;
 389         }
 390
 391 #ifdef HAVE_MKNOD
 392         if (am_root && preserve_devices && IS_DEVICE(file->mode)) {
 393                 if (statret != 0 ||
 394                     st.st_mode != file->mode ||
 395                     st.st_rdev != file->u.rdev) {
 396                         delete_file(fname);
 397                         if (verbose > 2) {
 398                                 rprintf(FINFO,"mknod(%s,0%o,0x%x)\n",
 399                                         fname,(int)file->mode,(int)file->u.rdev);
 400                         }
 401                         if (do_mknod(fname,file->mode,file->u.rdev) != 0) {
 402                                 rsyserr(FERROR, errno, "mknod %s failed",
 403                                         full_fname(fname));
 404                         } else {
 405                                 set_perms(fname,file,NULL,0);
 406                                 if (verbose)
 407                                         rprintf(FINFO,"%s\n",fname);
 408                         }
 409                 } else {
 410                         set_perms(fname, file, &st, PERMS_REPORT);
 411                 }
 412                 return;
 413         }
 414 #endif
 415
 416         if (preserve_hard_links && hard_link_check(file, HL_CHECK_MASTER))
 417                 return;
 418
 419         if (!S_ISREG(file->mode)) {
 420                 rprintf(FINFO, "skipping non-regular file \"%s\"\n",fname);
 421                 return;
 422         }
 423
 424         fnamecmp = fname;
 425
 426         if (statret == -1 && compare_dest != NULL) {
 427                 /* try the file at compare_dest instead */
 428                 int saveerrno = errno;
 429                 pathjoin(fnamecmpbuf, sizeof fnamecmpbuf, compare_dest, fname);
 430                 statret = link_stat(fnamecmpbuf, &st, 0);
 431                 if (!S_ISREG(st.st_mode))
 432                         statret = -1;
 433                 if (statret == -1)
 434                         errno = saveerrno;
 435 #if HAVE_LINK
 436                 else if (link_dest && !dry_run) {
 437                         if (do_link(fnamecmpbuf, fname) != 0) {
 438                                 if (verbose > 0) {
 439                                         rsyserr(FINFO, errno, "link %s => %s",
 440                                                 fnamecmpbuf, fname);
 441                                 }
 442                         }
 443                         fnamecmp = fnamecmpbuf;
 444                 }
 445 #endif
 446                 else
 447                         fnamecmp = fnamecmpbuf;
 448         }
 449
 450         if (statret == -1) {
 451                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 452                         return;
 453                 if (errno == ENOENT) {
 454                         write_int(f_out,i);
 455                         if (!dry_run)
 456                                 write_sum_head(f_out, NULL);
 457                 } else if (verbose > 1) {
 458                         rsyserr(FERROR, errno,
 459                                 "recv_generator: failed to open %s",
 460                                 full_fname(fname));
 461                 }
 462                 return;
 463         }
 464
 465         if (!S_ISREG(st.st_mode)) {
 466                 if (delete_file(fname) != 0) {
 467                         return;
 468                 }
 469
 470                 /* now pretend the file didn't exist */
 471                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 472                         return;
 473                 write_int(f_out,i);
 474                 if (!dry_run)
 475                         write_sum_head(f_out, NULL);
 476                 return;
 477         }
 478
 479         if (opt_ignore_existing && fnamecmp == fname) {
 480                 if (verbose > 1)
 481                         rprintf(FINFO,"%s exists\n",fname);
 482                 return;
 483         }
 484
 485         if (update_only && cmp_modtime(st.st_mtime,file->modtime)>0 && fnamecmp == fname) {
 486                 if (verbose > 1)
 487                         rprintf(FINFO,"%s is newer\n",fname);
 488                 return;
 489         }
 490
 491         if (skip_file(fname, file, &st)) {
 492                 if (fnamecmp == fname)
 493                         set_perms(fname, file, &st, PERMS_REPORT);
 494                 return;
 495         }
 496
 497         if (dry_run) {
 498                 write_int(f_out,i);
 499                 return;
 500         }
 501
 502         if (disable_deltas_p()) {
 503                 write_int(f_out,i);
 504                 write_sum_head(f_out, NULL);
 505                 return;
 506         }
 507
 508         /* open the file */
 509         fd = do_open(fnamecmp, O_RDONLY, 0);
 510
 511         if (fd == -1) {
 512                 rsyserr(FERROR, errno, "failed to open %s, continuing",
 513                         full_fname(fnamecmp));
 514                 /* pretend the file didn't exist */
 515                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 516                         return;
 517                 write_int(f_out,i);
 518                 write_sum_head(f_out, NULL);
 519                 return;
 520         }
 521
 522         if (st.st_size > 0)
 523                 mapbuf = map_file(fd,st.st_size);
 524         else
 525                 mapbuf = NULL;
 526
 527         if (verbose > 3) {
 528                 rprintf(FINFO,"gen mapped %s of size %.0f\n", fnamecmp,
 529                         (double)st.st_size);
 530         }
 531
 532         if (verbose > 2)
 533                 rprintf(FINFO, "generating and sending sums for %d\n", i);
 534
 535         write_int(f_out,i);
 536         generate_and_send_sums(mapbuf, st.st_size, f_out);
 537
 538         close(fd);
 539         if (mapbuf)
 540                 unmap_file(mapbuf);
 541 }
 542
 543
 544 void generate_files(int f, struct file_list *flist, char *local_name)
 545 {
 546         int i;
 547         int phase=0;
 548         char fbuf[MAXPATHLEN];
 549
 550         if (verbose > 2) {
 551                 rprintf(FINFO, "generator starting pid=%ld count=%d\n",
 552                         (long)getpid(), flist->count);
 553         }
 554
 555         if (verbose >= 2) {
 556                 rprintf(FINFO,
 557                         disable_deltas_p()
 558                         ? "delta-transmission disabled for local transfer or --whole-file\n"
 559                         : "delta transmission enabled\n");
 560         }
 561
 562         /* we expect to just sit around now, so don't exit on a
 563            timeout. If we really get a timeout then the other process should
 564            exit */
 565         io_timeout = 0;
 566
 567         for (i = 0; i < flist->count; i++) {
 568                 struct file_struct *file = flist->files[i];
 569                 struct file_struct copy;
 570
 571                 if (!file->basename)
 572                         continue;
 573                 /* we need to ensure that any directories we create have writeable
 574                    permissions initially so that we can create the files within
 575                    them. This is then fixed after the files are transferred */
 576                 if (!am_root && S_ISDIR(file->mode) && !(file->mode & S_IWUSR)) {
 577                         copy = *file;
 578                         /* XXX: Could this be causing a problem on SCO?  Perhaps their
 579                          * handling of permissions is strange? */
 580                         copy.mode |= S_IWUSR; /* user write */
 581                         file = &copy;
 582                 }
 583
 584                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 585                                file, i, f);
 586         }
 587
 588         phase++;
 589         csum_length = SUM_LENGTH;
 590         ignore_times=1;
 591
 592         if (verbose > 2)
 593                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 594
 595         write_int(f,-1);
 596
 597         /* files can cycle through the system more than once
 598          * to catch initial checksum errors */
 599         while ((i = get_redo_num()) != -1) {
 600                 struct file_struct *file = flist->files[i];
 601                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 602                                file, i, f);
 603         }
 604
 605         phase++;
 606         if (verbose > 2)
 607                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 608
 609         write_int(f,-1);
 610
 611         if (preserve_hard_links)
 612                 do_hard_links();
 613
 614         /* now we need to fix any directory permissions that were
 615          * modified during the transfer */
 616         for (i = 0; i < flist->count; i++) {
 617                 struct file_struct *file = flist->files[i];
 618                 if (!file->basename || !S_ISDIR(file->mode))
 619                         continue;
 620                 recv_generator(local_name ? local_name : f_name(file),
 621                                file, i, -1);
 622         }
 623
 624         if (verbose > 2)
 625                 rprintf(FINFO,"generate_files finished\n");
 626 }