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                 if (verbose) {
 290                         rprintf(FINFO, "skipping server-excluded file \"%s\"\n",
 291                                 fname);
 292                 }
 293                 return;
 294         }
 295
 296         statret = link_stat(fname,&st);
 297
 298         if (only_existing && statret == -1 && errno == ENOENT) {
 299                 /* we only want to update existing files */
 300                 if (verbose > 1)
 301                         rprintf(FINFO, "not creating new file \"%s\"\n", fname);
 302                 return;
 303         }
 304
 305         if (statret == 0 &&
 306             !preserve_perms &&
 307             (S_ISDIR(st.st_mode) == S_ISDIR(file->mode))) {
 308                 /* if the file exists already and we aren't perserving
 309                  * permissions then act as though the remote end sent
 310                  * us the file permissions we already have */
 311                 file->mode = (file->mode & ~CHMOD_BITS)
 312                            | (st.st_mode & CHMOD_BITS);
 313         }
 314
 315         if (S_ISDIR(file->mode)) {
 316                 /* The file to be received is a directory, so we need
 317                  * to prepare appropriately.  If there is already a
 318                  * file of that name and it is *not* a directory, then
 319                  * we need to delete it.  If it doesn't exist, then
 320                  * recursively create it. */
 321
 322                 if (dry_run) return; /* XXXX -- might cause inaccuracies?? -- mbp */
 323                 if (statret == 0 && !S_ISDIR(st.st_mode)) {
 324                         if (robust_unlink(fname) != 0) {
 325                                 rsyserr(FERROR, errno,
 326                                         "recv_generator: unlink %s to make room for directory",
 327                                         full_fname(fname));
 328                                 return;
 329                         }
 330                         statret = -1;
 331                 }
 332                 if (statret != 0 && do_mkdir(fname,file->mode) != 0 && errno != EEXIST) {
 333                         if (!(relative_paths && errno == ENOENT
 334                             && create_directory_path(fname, orig_umask) == 0
 335                             && do_mkdir(fname, file->mode) == 0)) {
 336                                 rsyserr(FERROR, errno,
 337                                         "recv_generator: mkdir %s failed",
 338                                         full_fname(fname));
 339                         }
 340                 }
 341                 /* f_out is set to -1 when doing final directory
 342                    permission and modification time repair */
 343                 if (set_perms(fname,file,NULL,0) && 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);
 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) write_sum_head(f_out, NULL);
 456                 } else if (verbose > 1) {
 457                         rsyserr(FERROR, errno,
 458                                 "recv_generator: failed to open %s",
 459                                 full_fname(fname));
 460                 }
 461                 return;
 462         }
 463
 464         if (!S_ISREG(st.st_mode)) {
 465                 if (delete_file(fname) != 0) {
 466                         return;
 467                 }
 468
 469                 /* now pretend the file didn't exist */
 470                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 471                         return;
 472                 write_int(f_out,i);
 473                 if (!dry_run) write_sum_head(f_out, NULL);
 474                 return;
 475         }
 476
 477         if (opt_ignore_existing && fnamecmp == fname) {
 478                 if (verbose > 1)
 479                         rprintf(FINFO,"%s exists\n",fname);
 480                 return;
 481         }
 482
 483         if (update_only && cmp_modtime(st.st_mtime,file->modtime)>0 && fnamecmp == fname) {
 484                 if (verbose > 1)
 485                         rprintf(FINFO,"%s is newer\n",fname);
 486                 return;
 487         }
 488
 489         if (skip_file(fname, file, &st)) {
 490                 if (fnamecmp == fname)
 491                         set_perms(fname, file, &st, PERMS_REPORT);
 492                 return;
 493         }
 494
 495         if (dry_run) {
 496                 write_int(f_out,i);
 497                 return;
 498         }
 499
 500         if (disable_deltas_p()) {
 501                 write_int(f_out,i);
 502                 write_sum_head(f_out, NULL);
 503                 return;
 504         }
 505
 506         /* open the file */
 507         fd = do_open(fnamecmp, O_RDONLY, 0);
 508
 509         if (fd == -1) {
 510                 rsyserr(FERROR, errno, "failed to open %s, continuing",
 511                         full_fname(fnamecmp));
 512                 /* pretend the file didn't exist */
 513                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 514                         return;
 515                 write_int(f_out,i);
 516                 write_sum_head(f_out, NULL);
 517                 return;
 518         }
 519
 520         if (st.st_size > 0)
 521                 mapbuf = map_file(fd,st.st_size);
 522         else
 523                 mapbuf = NULL;
 524
 525         if (verbose > 3) {
 526                 rprintf(FINFO,"gen mapped %s of size %.0f\n", fnamecmp,
 527                         (double)st.st_size);
 528         }
 529
 530         if (verbose > 2)
 531                 rprintf(FINFO, "generating and sending sums for %d\n", i);
 532
 533         write_int(f_out,i);
 534         generate_and_send_sums(mapbuf, st.st_size, f_out);
 535
 536         close(fd);
 537         if (mapbuf) unmap_file(mapbuf);
 538 }
 539
 540
 541 void generate_files(int f, struct file_list *flist, char *local_name)
 542 {
 543         int i;
 544         int phase=0;
 545         char fbuf[MAXPATHLEN];
 546
 547         if (verbose > 2) {
 548                 rprintf(FINFO, "generator starting pid=%ld count=%d\n",
 549                         (long)getpid(), flist->count);
 550         }
 551
 552         if (verbose >= 2) {
 553                 rprintf(FINFO,
 554                         disable_deltas_p()
 555                         ? "delta-transmission disabled for local transfer or --whole-file\n"
 556                         : "delta transmission enabled\n");
 557         }
 558
 559         /* we expect to just sit around now, so don't exit on a
 560            timeout. If we really get a timeout then the other process should
 561            exit */
 562         io_timeout = 0;
 563
 564         for (i = 0; i < flist->count; i++) {
 565                 struct file_struct *file = flist->files[i];
 566                 struct file_struct copy;
 567
 568                 if (!file->basename)
 569                         continue;
 570                 /* we need to ensure that any directories we create have writeable
 571                    permissions initially so that we can create the files within
 572                    them. This is then fixed after the files are transferred */
 573                 if (!am_root && S_ISDIR(file->mode) && !(file->mode & S_IWUSR)) {
 574                         copy = *file;
 575                         /* XXX: Could this be causing a problem on SCO?  Perhaps their
 576                          * handling of permissions is strange? */
 577                         copy.mode |= S_IWUSR; /* user write */
 578                         file = &copy;
 579                 }
 580
 581                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 582                                file, i, f);
 583         }
 584
 585         phase++;
 586         csum_length = SUM_LENGTH;
 587         ignore_times=1;
 588
 589         if (verbose > 2)
 590                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 591
 592         write_int(f,-1);
 593
 594         /* files can cycle through the system more than once
 595          * to catch initial checksum errors */
 596         while ((i = get_redo_num()) != -1) {
 597                 struct file_struct *file = flist->files[i];
 598                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 599                                file, i, f);
 600         }
 601
 602         phase++;
 603         if (verbose > 2)
 604                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 605
 606         write_int(f,-1);
 607
 608         if (preserve_hard_links)
 609                 do_hard_links();
 610
 611         /* now we need to fix any directory permissions that were
 612          * modified during the transfer */
 613         for (i = 0; i < flist->count; i++) {
 614                 struct file_struct *file = flist->files[i];
 615                 if (!file->basename || !S_ISDIR(file->mode)) continue;
 616                 recv_generator(local_name ? local_name : f_name(file),
 617                                file, i, -1);
 618         }
 619
 620         if (verbose > 2)
 621                 rprintf(FINFO,"generate_files finished\n");
 622 }