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                                 rsyserr(FERROR, errno,
 313                                         "recv_generator: unlink %s to make room for directory",
 314                                         full_fname(fname));
 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                                 rsyserr(FERROR, errno,
 324                                         "recv_generator: mkdir %s failed",
 325                                         full_fname(fname));
 326                         }
 327                 }
 328                 /* f_out is set to -1 when doing final directory
 329                    permission and modification time repair */
 330                 if (set_perms(fname,file,NULL,0) && verbose && (f_out != -1))
 331                         rprintf(FINFO,"%s/\n",fname);
 332                 return;
 333         }
 334
 335         if (preserve_links && S_ISLNK(file->mode)) {
 336 #if SUPPORT_LINKS
 337                 char lnk[MAXPATHLEN];
 338                 int l;
 339
 340                 if (safe_symlinks && unsafe_symlink(file->u.link, fname)) {
 341                         if (verbose) {
 342                                 rprintf(FINFO, "ignoring unsafe symlink %s -> \"%s\"\n",
 343                                         full_fname(fname), file->u.link);
 344                         }
 345                         return;
 346                 }
 347                 if (statret == 0) {
 348                         l = readlink(fname,lnk,MAXPATHLEN-1);
 349                         if (l > 0) {
 350                                 lnk[l] = 0;
 351                                 /* A link already pointing to the
 352                                  * right place -- no further action
 353                                  * required. */
 354                                 if (strcmp(lnk,file->u.link) == 0) {
 355                                         set_perms(fname, file, &st,
 356                                                   PERMS_REPORT);
 357                                         return;
 358                                 }
 359                         }
 360                         /* Not a symlink, so delete whatever's
 361                          * already there and put a new symlink
 362                          * in place. */
 363                         delete_file(fname);
 364                 }
 365                 if (do_symlink(file->u.link,fname) != 0) {
 366                         rsyserr(FERROR, errno, "symlink %s -> \"%s\" failed",
 367                                 full_fname(fname), file->u.link);
 368                 } else {
 369                         set_perms(fname,file,NULL,0);
 370                         if (verbose) {
 371                                 rprintf(FINFO,"%s -> %s\n", fname,file->u.link);
 372                         }
 373                 }
 374 #endif
 375                 return;
 376         }
 377
 378 #ifdef HAVE_MKNOD
 379         if (am_root && preserve_devices && IS_DEVICE(file->mode)) {
 380                 if (statret != 0 ||
 381                     st.st_mode != file->mode ||
 382                     st.st_rdev != file->u.rdev) {
 383                         delete_file(fname);
 384                         if (verbose > 2) {
 385                                 rprintf(FINFO,"mknod(%s,0%o,0x%x)\n",
 386                                         fname,(int)file->mode,(int)file->u.rdev);
 387                         }
 388                         if (do_mknod(fname,file->mode,file->u.rdev) != 0) {
 389                                 rsyserr(FERROR, errno, "mknod %s failed",
 390                                         full_fname(fname));
 391                         } else {
 392                                 set_perms(fname,file,NULL,0);
 393                                 if (verbose)
 394                                         rprintf(FINFO,"%s\n",fname);
 395                         }
 396                 } else {
 397                         set_perms(fname, file, &st, PERMS_REPORT);
 398                 }
 399                 return;
 400         }
 401 #endif
 402
 403         if (preserve_hard_links && hard_link_check(file, HL_CHECK_MASTER))
 404                 return;
 405
 406         if (!S_ISREG(file->mode)) {
 407                 rprintf(FINFO, "skipping non-regular file \"%s\"\n",fname);
 408                 return;
 409         }
 410
 411         fnamecmp = fname;
 412
 413         if (statret == -1 && compare_dest != NULL) {
 414                 /* try the file at compare_dest instead */
 415                 int saveerrno = errno;
 416                 pathjoin(fnamecmpbuf, sizeof fnamecmpbuf, compare_dest, fname);
 417                 statret = link_stat(fnamecmpbuf,&st);
 418                 if (!S_ISREG(st.st_mode))
 419                         statret = -1;
 420                 if (statret == -1)
 421                         errno = saveerrno;
 422 #if HAVE_LINK
 423                 else if (link_dest && !dry_run) {
 424                         if (do_link(fnamecmpbuf, fname) != 0) {
 425                                 if (verbose > 0) {
 426                                         rsyserr(FINFO, errno, "link %s => %s",
 427                                                 fnamecmpbuf, fname);
 428                                 }
 429                         }
 430                         fnamecmp = fnamecmpbuf;
 431                 }
 432 #endif
 433                 else
 434                         fnamecmp = fnamecmpbuf;
 435         }
 436
 437         if (statret == -1) {
 438                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 439                         return;
 440                 if (errno == ENOENT) {
 441                         write_int(f_out,i);
 442                         if (!dry_run) write_sum_head(f_out, NULL);
 443                 } else if (verbose > 1) {
 444                         rsyserr(FERROR, errno,
 445                                 "recv_generator: failed to open %s",
 446                                 full_fname(fname));
 447                 }
 448                 return;
 449         }
 450
 451         if (!S_ISREG(st.st_mode)) {
 452                 if (delete_file(fname) != 0) {
 453                         return;
 454                 }
 455
 456                 /* now pretend the file didn't exist */
 457                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 458                         return;
 459                 write_int(f_out,i);
 460                 if (!dry_run) write_sum_head(f_out, NULL);
 461                 return;
 462         }
 463
 464         if (opt_ignore_existing && fnamecmp == fname) {
 465                 if (verbose > 1)
 466                         rprintf(FINFO,"%s exists\n",fname);
 467                 return;
 468         }
 469
 470         if (update_only && cmp_modtime(st.st_mtime,file->modtime)>0 && fnamecmp == fname) {
 471                 if (verbose > 1)
 472                         rprintf(FINFO,"%s is newer\n",fname);
 473                 return;
 474         }
 475
 476         if (skip_file(fname, file, &st)) {
 477                 if (fnamecmp == fname)
 478                         set_perms(fname, file, &st, PERMS_REPORT);
 479                 return;
 480         }
 481
 482         if (dry_run) {
 483                 write_int(f_out,i);
 484                 return;
 485         }
 486
 487         if (disable_deltas_p()) {
 488                 write_int(f_out,i);
 489                 write_sum_head(f_out, NULL);
 490                 return;
 491         }
 492
 493         /* open the file */
 494         fd = do_open(fnamecmp, O_RDONLY, 0);
 495
 496         if (fd == -1) {
 497                 rsyserr(FERROR, errno, "failed to open %s, continuing",
 498                         full_fname(fnamecmp));
 499                 /* pretend the file didn't exist */
 500                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 501                         return;
 502                 write_int(f_out,i);
 503                 write_sum_head(f_out, NULL);
 504                 return;
 505         }
 506
 507         if (st.st_size > 0)
 508                 mapbuf = map_file(fd,st.st_size);
 509         else
 510                 mapbuf = NULL;
 511
 512         if (verbose > 3) {
 513                 rprintf(FINFO,"gen mapped %s of size %.0f\n", fnamecmp,
 514                         (double)st.st_size);
 515         }
 516
 517         if (verbose > 2)
 518                 rprintf(FINFO, "generating and sending sums for %d\n", i);
 519
 520         write_int(f_out,i);
 521         generate_and_send_sums(mapbuf, st.st_size, f_out);
 522
 523         close(fd);
 524         if (mapbuf) unmap_file(mapbuf);
 525 }
 526
 527
 528 void generate_files(int f, struct file_list *flist, char *local_name)
 529 {
 530         int i;
 531         int phase=0;
 532         char fbuf[MAXPATHLEN];
 533
 534         if (verbose > 2) {
 535                 rprintf(FINFO, "generator starting pid=%ld count=%d\n",
 536                         (long)getpid(), flist->count);
 537         }
 538
 539         if (verbose >= 2) {
 540                 rprintf(FINFO,
 541                         disable_deltas_p()
 542                         ? "delta-transmission disabled for local transfer or --whole-file\n"
 543                         : "delta transmission enabled\n");
 544         }
 545
 546         /* we expect to just sit around now, so don't exit on a
 547            timeout. If we really get a timeout then the other process should
 548            exit */
 549         io_timeout = 0;
 550
 551         for (i = 0; i < flist->count; i++) {
 552                 struct file_struct *file = flist->files[i];
 553                 struct file_struct copy;
 554
 555                 if (!file->basename)
 556                         continue;
 557                 /* we need to ensure that any directories we create have writeable
 558                    permissions initially so that we can create the files within
 559                    them. This is then fixed after the files are transferred */
 560                 if (!am_root && S_ISDIR(file->mode) && !(file->mode & S_IWUSR)) {
 561                         copy = *file;
 562                         /* XXX: Could this be causing a problem on SCO?  Perhaps their
 563                          * handling of permissions is strange? */
 564                         copy.mode |= S_IWUSR; /* user write */
 565                         file = &copy;
 566                 }
 567
 568                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 569                                file, i, f);
 570         }
 571
 572         phase++;
 573         csum_length = SUM_LENGTH;
 574         ignore_times=1;
 575
 576         if (verbose > 2)
 577                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 578
 579         write_int(f,-1);
 580
 581         /* files can cycle through the system more than once
 582          * to catch initial checksum errors */
 583         while ((i = get_redo_num()) != -1) {
 584                 struct file_struct *file = flist->files[i];
 585                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 586                                file, i, f);
 587         }
 588
 589         phase++;
 590         if (verbose > 2)
 591                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 592
 593         write_int(f,-1);
 594
 595         if (preserve_hard_links)
 596                 do_hard_links();
 597
 598         /* now we need to fix any directory permissions that were
 599          * modified during the transfer */
 600         for (i = 0; i < flist->count; i++) {
 601                 struct file_struct *file = flist->files[i];
 602                 if (!file->basename || !S_ISDIR(file->mode)) continue;
 603                 recv_generator(local_name ? local_name : f_name(file),
 604                                file, i, -1);
 605         }
 606
 607         if (verbose > 2)
 608                 rprintf(FINFO,"generate_files finished\n");
 609 }