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