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
  56 /* choose whether to skip a particular file */
  57 static int skip_file(char *fname, struct file_struct *file, STRUCT_STAT *st)
  58 {
  59         if (st->st_size != file->length) {
  60                 return 0;
  61         }
  62         if (link_dest) {
  63                 if (preserve_perms
  64                     && (st->st_mode & CHMOD_BITS) != (file->mode & CHMOD_BITS))
  65                         return 0;
  66
  67                 if (am_root && preserve_uid && st->st_uid != file->uid)
  68                         return 0;
  69
  70                 if (preserve_gid && file->gid != GID_NONE
  71                     && st->st_gid != file->gid)
  72                         return 0;
  73         }
  74
  75         /* if always checksum is set then we use the checksum instead
  76            of the file time to determine whether to sync */
  77         if (always_checksum && S_ISREG(st->st_mode)) {
  78                 char sum[MD4_SUM_LENGTH];
  79                 char fnamecmpdest[MAXPATHLEN];
  80
  81                 if (compare_dest != NULL) {
  82                         if (access(fname, 0) != 0) {
  83                                 pathjoin(fnamecmpdest, sizeof fnamecmpdest,
  84                                          compare_dest, fname);
  85                                 fname = fnamecmpdest;
  86                         }
  87                 }
  88                 file_checksum(fname,sum,st->st_size);
  89                 return memcmp(sum, file->u.sum, protocol_version < 21 ? 2
  90                                                         : MD4_SUM_LENGTH) == 0;
  91         }
  92
  93         if (size_only) {
  94                 return 1;
  95         }
  96
  97         if (ignore_times) {
  98                 return 0;
  99         }
 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  * calulating dynamic block ans checksum sizes.
 125  *
 126  * This is only called from generate_and_send_sums() but is a seperate
 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         extern unsigned int block_size;
 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         statret = link_stat(fname,&st);
 285
 286         if (only_existing && statret == -1 && errno == ENOENT) {
 287                 /* we only want to update existing files */
 288                 if (verbose > 1) rprintf(FINFO, "not creating new file \"%s\"\n",fname);
 289                 return;
 290         }
 291
 292         if (statret == 0 &&
 293             !preserve_perms &&
 294             (S_ISDIR(st.st_mode) == S_ISDIR(file->mode))) {
 295                 /* if the file exists already and we aren't perserving
 296                  * permissions then act as though the remote end sent
 297                  * us the file permissions we already have */
 298                 file->mode = (file->mode & ~CHMOD_BITS)
 299                            | (st.st_mode & CHMOD_BITS);
 300         }
 301
 302         if (S_ISDIR(file->mode)) {
 303                 /* The file to be received is a directory, so we need
 304                  * to prepare appropriately.  If there is already a
 305                  * file of that name and it is *not* a directory, then
 306                  * we need to delete it.  If it doesn't exist, then
 307                  * recursively create it. */
 308
 309                 if (dry_run) return; /* XXXX -- might cause inaccuracies?? -- mbp */
 310                 if (statret == 0 && !S_ISDIR(st.st_mode)) {
 311                         if (robust_unlink(fname) != 0) {
 312                                 rprintf(FERROR,
 313                                         "recv_generator: unlink %s to make room for directory: %s\n",
 314                                         full_fname(fname), strerror(errno));
 315                                 return;
 316                         }
 317                         statret = -1;
 318                 }
 319                 if (statret != 0 && do_mkdir(fname,file->mode) != 0 && errno != EEXIST) {
 320                         if (!(relative_paths && errno==ENOENT &&
 321                               create_directory_path(fname, orig_umask)==0 &&
 322                               do_mkdir(fname,file->mode)==0)) {
 323                                 rprintf(FERROR, "recv_generator: mkdir %s failed: %s\n",
 324                                         full_fname(fname), strerror(errno));
 325                         }
 326                 }
 327                 /* f_out is set to -1 when doing final directory
 328                    permission and modification time repair */
 329                 if (set_perms(fname,file,NULL,0) && verbose && (f_out != -1))
 330                         rprintf(FINFO,"%s/\n",fname);
 331                 return;
 332         }
 333
 334         if (preserve_links && S_ISLNK(file->mode)) {
 335 #if SUPPORT_LINKS
 336                 char lnk[MAXPATHLEN];
 337                 int l;
 338
 339                 if (safe_symlinks && unsafe_symlink(file->u.link, fname)) {
 340                         if (verbose) {
 341                                 rprintf(FINFO, "ignoring unsafe symlink %s -> \"%s\"\n",
 342                                         full_fname(fname), file->u.link);
 343                         }
 344                         return;
 345                 }
 346                 if (statret == 0) {
 347                         l = readlink(fname,lnk,MAXPATHLEN-1);
 348                         if (l > 0) {
 349                                 lnk[l] = 0;
 350                                 /* A link already pointing to the
 351                                  * right place -- no further action
 352                                  * required. */
 353                                 if (strcmp(lnk,file->u.link) == 0) {
 354                                         set_perms(fname,file,&st,1);
 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                         rprintf(FERROR, "symlink %s -> \"%s\" failed: %s\n",
 365                                 full_fname(fname), file->u.link, strerror(errno));
 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                         if (do_mknod(fname,file->mode,file->u.rdev) != 0) {
 386                                 rprintf(FERROR, "mknod %s failed: %s\n",
 387                                         full_fname(fname), strerror(errno));
 388                         } else {
 389                                 set_perms(fname,file,NULL,0);
 390                                 if (verbose)
 391                                         rprintf(FINFO,"%s\n",fname);
 392                         }
 393                 } else {
 394                         set_perms(fname,file,&st,1);
 395                 }
 396                 return;
 397         }
 398 #endif
 399
 400         if (preserve_hard_links && hard_link_check(file, HL_CHECK_MASTER))
 401                 return;
 402
 403         if (!S_ISREG(file->mode)) {
 404                 rprintf(FINFO, "skipping non-regular file \"%s\"\n",fname);
 405                 return;
 406         }
 407
 408         fnamecmp = fname;
 409
 410         if (statret == -1 && compare_dest != NULL) {
 411                 /* try the file at compare_dest instead */
 412                 int saveerrno = errno;
 413                 pathjoin(fnamecmpbuf, sizeof fnamecmpbuf, compare_dest, fname);
 414                 statret = link_stat(fnamecmpbuf,&st);
 415                 if (!S_ISREG(st.st_mode))
 416                         statret = -1;
 417                 if (statret == -1)
 418                         errno = saveerrno;
 419 #if HAVE_LINK
 420                 else if (link_dest && !dry_run) {
 421                         if (do_link(fnamecmpbuf, fname) != 0) {
 422                                 if (verbose > 0) {
 423                                         rprintf(FINFO,"link %s => %s : %s\n",
 424                                                 fnamecmpbuf, fname,
 425                                                 strerror(errno));
 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) write_sum_head(f_out, NULL);
 441                 } else if (verbose > 1) {
 442                         rprintf(FERROR,
 443                                 "recv_generator: failed to open %s: %s\n",
 444                                 full_fname(fname), strerror(errno));
 445                 }
 446                 return;
 447         }
 448
 449         if (!S_ISREG(st.st_mode)) {
 450                 if (delete_file(fname) != 0) {
 451                         return;
 452                 }
 453
 454                 /* now pretend the file didn't exist */
 455                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 456                         return;
 457                 write_int(f_out,i);
 458                 if (!dry_run) write_sum_head(f_out, NULL);
 459                 return;
 460         }
 461
 462         if (opt_ignore_existing && fnamecmp == fname) {
 463                 if (verbose > 1)
 464                         rprintf(FINFO,"%s exists\n",fname);
 465                 return;
 466         }
 467
 468         if (update_only && cmp_modtime(st.st_mtime,file->modtime)>0 && fnamecmp == fname) {
 469                 if (verbose > 1)
 470                         rprintf(FINFO,"%s is newer\n",fname);
 471                 return;
 472         }
 473
 474         if (skip_file(fname, file, &st)) {
 475                 if (fnamecmp == fname)
 476                         set_perms(fname,file,&st,1);
 477                 return;
 478         }
 479
 480         if (dry_run) {
 481                 write_int(f_out,i);
 482                 return;
 483         }
 484
 485         if (disable_deltas_p()) {
 486                 write_int(f_out,i);
 487                 write_sum_head(f_out, NULL);
 488                 return;
 489         }
 490
 491         /* open the file */
 492         fd = do_open(fnamecmp, O_RDONLY, 0);
 493
 494         if (fd == -1) {
 495                 rprintf(FERROR, "failed to open %s, continuing: %s\n",
 496                         full_fname(fnamecmp), strerror(errno));
 497                 /* pretend the file didn't exist */
 498                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 499                         return;
 500                 write_int(f_out,i);
 501                 write_sum_head(f_out, NULL);
 502                 return;
 503         }
 504
 505         if (st.st_size > 0)
 506                 mapbuf = map_file(fd,st.st_size);
 507         else
 508                 mapbuf = NULL;
 509
 510         if (verbose > 3) {
 511                 rprintf(FINFO,"gen mapped %s of size %.0f\n", fnamecmp,
 512                         (double)st.st_size);
 513         }
 514
 515         if (verbose > 2)
 516                 rprintf(FINFO, "generating and sending sums for %d\n", i);
 517
 518         write_int(f_out,i);
 519         generate_and_send_sums(mapbuf, st.st_size, f_out);
 520
 521         close(fd);
 522         if (mapbuf) unmap_file(mapbuf);
 523 }
 524
 525
 526 void generate_files(int f, struct file_list *flist, char *local_name)
 527 {
 528         int i;
 529         int phase=0;
 530         char fbuf[MAXPATHLEN];
 531
 532         if (verbose > 2) {
 533                 rprintf(FINFO, "generator starting pid=%ld count=%d\n",
 534                         (long)getpid(), flist->count);
 535         }
 536
 537         if (verbose >= 2) {
 538                 rprintf(FINFO,
 539                         disable_deltas_p()
 540                         ? "delta-transmission disabled for local transfer or --whole-file\n"
 541                         : "delta transmission enabled\n");
 542         }
 543
 544         /* we expect to just sit around now, so don't exit on a
 545            timeout. If we really get a timeout then the other process should
 546            exit */
 547         io_timeout = 0;
 548
 549         for (i = 0; i < flist->count; i++) {
 550                 struct file_struct *file = flist->files[i];
 551                 struct file_struct copy;
 552
 553                 if (!file->basename)
 554                         continue;
 555                 /* we need to ensure that any directories we create have writeable
 556                    permissions initially so that we can create the files within
 557                    them. This is then fixed after the files are transferred */
 558                 if (!am_root && S_ISDIR(file->mode) && !(file->mode & S_IWUSR)) {
 559                         copy = *file;
 560                         /* XXX: Could this be causing a problem on SCO?  Perhaps their
 561                          * handling of permissions is strange? */
 562                         copy.mode |= S_IWUSR; /* user write */
 563                         file = &copy;
 564                 }
 565
 566                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 567                                file, i, f);
 568         }
 569
 570         phase++;
 571         csum_length = SUM_LENGTH;
 572         ignore_times=1;
 573
 574         if (verbose > 2)
 575                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 576
 577         write_int(f,-1);
 578
 579         /* files can cycle through the system more than once
 580          * to catch initial checksum errors */
 581         while ((i = get_redo_num()) != -1) {
 582                 struct file_struct *file = flist->files[i];
 583                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 584                                file, i, f);
 585         }
 586
 587         phase++;
 588         if (verbose > 2)
 589                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 590
 591         write_int(f,-1);
 592
 593         if (preserve_hard_links)
 594                 do_hard_links();
 595
 596         /* now we need to fix any directory permissions that were
 597          * modified during the transfer */
 598         for (i = 0; i < flist->count; i++) {
 599                 struct file_struct *file = flist->files[i];
 600                 if (!file->basename || !S_ISDIR(file->mode)) continue;
 601                 recv_generator(local_name ? local_name : f_name(file),
 602                                file, i, -1);
 603         }
 604
 605         if (verbose > 2)
 606                 rprintf(FINFO,"generate_files finished\n");
 607 }