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
  47
  48 /* choose whether to skip a particular file */
  49 static int skip_file(char *fname, struct file_struct *file, STRUCT_STAT *st)
  50 {
  51         if (st->st_size != file->length) {
  52                 return 0;
  53         }
  54         if (link_dest) {
  55                 if (preserve_perms
  56                     && (st->st_mode & CHMOD_BITS) != (file->mode & CHMOD_BITS))
  57                         return 0;
  58
  59                 if (am_root && preserve_uid && st->st_uid != file->uid)
  60                         return 0;
  61
  62                 if (preserve_gid && file->gid != GID_NONE
  63                     && st->st_gid != file->gid)
  64                         return 0;
  65         }
  66
  67         /* if always checksum is set then we use the checksum instead
  68            of the file time to determine whether to sync */
  69         if (always_checksum && S_ISREG(st->st_mode)) {
  70                 char sum[MD4_SUM_LENGTH];
  71                 char fnamecmpdest[MAXPATHLEN];
  72
  73                 if (compare_dest != NULL) {
  74                         if (access(fname, 0) != 0) {
  75                                 pathjoin(fnamecmpdest, sizeof fnamecmpdest,
  76                                          compare_dest, fname);
  77                                 fname = fnamecmpdest;
  78                         }
  79                 }
  80                 file_checksum(fname,sum,st->st_size);
  81                 return memcmp(sum, file->u.sum, protocol_version < 21 ? 2
  82                                                         : MD4_SUM_LENGTH) == 0;
  83         }
  84
  85         if (size_only) {
  86                 return 1;
  87         }
  88
  89         if (ignore_times) {
  90                 return 0;
  91         }
  92
  93         return (cmp_modtime(st->st_mtime,file->modtime) == 0);
  94 }
  95
  96
  97 /*
  98  * NULL sum_struct means we have no checksums
  99  */
 100 void write_sum_head(int f, struct sum_struct *sum)
 101 {
 102         static struct sum_struct null_sum;
 103
 104         if (sum == NULL)
 105                 sum = &null_sum;
 106
 107         write_int(f, sum->count);
 108         write_int(f, sum->blength);
 109         if (protocol_version >= 27)
 110                 write_int(f, sum->s2length);
 111         write_int(f, sum->remainder);
 112 }
 113
 114 /*
 115  * set (initialize) the size entries in the per-file sum_struct
 116  * calulating dynamic block ans checksum sizes.
 117  *
 118  * This is only called from generate_and_send_sums() but is a seperate
 119  * function to encapsulate the logic.
 120  *
 121  * The block size is a rounded square root of file length.
 122  *
 123  * The checksum size is determined according to:
 124  *     blocksum_bits = BLOCKSUM_EXP + 2*log2(file_len) - log2(block_len)
 125  * provided by Donovan Baarda which gives a probability of rsync
 126  * algorithm corrupting data and falling back using the whole md4
 127  * checksums.
 128  *
 129  * This might be made one of several selectable heuristics.
 130  */
 131
 132 static void sum_sizes_sqroot(struct sum_struct *sum, uint64 len)
 133 {
 134         extern unsigned int block_size;
 135         unsigned int blength;
 136         int s2length;
 137         uint32 c;
 138         uint64 l;
 139
 140         if (block_size) {
 141                 blength = block_size;
 142         } else if (len <= BLOCK_SIZE * BLOCK_SIZE) {
 143                 blength = BLOCK_SIZE;
 144         } else {
 145                 l = len;
 146                 c = 1;
 147                 while (l >>= 2) {
 148                         c <<= 1;
 149                 }
 150                 blength = 0;
 151                 do {
 152                         blength |= c;
 153                         if (len < (uint64)blength * blength)
 154                                 blength &= ~c;
 155                         c >>= 1;
 156                 } while (c >= 8);       /* round to multiple of 8 */
 157                 blength = MAX(blength, BLOCK_SIZE);
 158         }
 159
 160         if (protocol_version < 27) {
 161                 s2length = csum_length;
 162         } else if (csum_length == SUM_LENGTH) {
 163                 s2length = SUM_LENGTH;
 164         } else {
 165                 int b = BLOCKSUM_BIAS;
 166                 l = len;
 167                 while (l >>= 1) {
 168                         b += 2;
 169                 }
 170                 c = blength;
 171                 while (c >>= 1 && b) {
 172                         b--;
 173                 }
 174                 s2length = (b + 1 - 32 + 7) / 8; /* add a bit,
 175                                                   * subtract rollsum,
 176                                                   * round up
 177                                                   *    --optimize in compiler--
 178                                                   */
 179                 s2length = MAX(s2length, csum_length);
 180                 s2length = MIN(s2length, SUM_LENGTH);
 181         }
 182
 183         sum->flength    = len;
 184         sum->blength    = blength;
 185         sum->s2length   = s2length;
 186         sum->count      = (len + (blength - 1)) / blength;
 187         sum->remainder  = (len % blength);
 188
 189         if (sum->count && verbose > 2) {
 190                 rprintf(FINFO, "count=%.0f rem=%u blength=%u s2length=%d flength=%.0f\n",
 191                         (double)sum->count, sum->remainder, sum->blength,
 192                         sum->s2length, (double)sum->flength);
 193         }
 194 }
 195
 196 /**
 197  * Perhaps we want to just send an empty checksum set for this file,
 198  * which will force the whole thing to be literally transferred.
 199  *
 200  * When do we do this?  If the user's explicitly said they
 201  * want the whole thing, or if { they haven't explicitly
 202  * requested a delta, and it's local but not batch mode.}
 203  *
 204  * Whew. */
 205 static BOOL disable_deltas_p(void)
 206 {
 207         extern int whole_file;
 208         extern int local_server;
 209         extern int write_batch;
 210
 211         if (whole_file > 0)
 212                 return True;
 213         if (whole_file == 0 || write_batch)
 214                 return False;
 215         return local_server;
 216 }
 217
 218
 219 /*
 220  * Generate and send a stream of signatures/checksums that describe a buffer
 221  *
 222  * Generate approximately one checksum every block_len bytes.
 223  */
 224 static void generate_and_send_sums(struct map_struct *buf, size_t len, int f_out)
 225 {
 226         size_t i;
 227         struct sum_struct sum;
 228         OFF_T offset = 0;
 229
 230         sum_sizes_sqroot(&sum, len);
 231
 232         write_sum_head(f_out, &sum);
 233
 234         for (i = 0; i < sum.count; i++) {
 235                 unsigned int n1 = MIN(len, sum.blength);
 236                 char *map = map_ptr(buf, offset, n1);
 237                 uint32 sum1 = get_checksum1(map, n1);
 238                 char sum2[SUM_LENGTH];
 239
 240                 get_checksum2(map, n1, sum2);
 241
 242                 if (verbose > 3) {
 243                         rprintf(FINFO,
 244                                 "chunk[%.0f] offset=%.0f len=%u sum1=%08lx\n",
 245                                 (double)i, (double)offset, n1,
 246                                 (unsigned long)sum1);
 247                 }
 248                 write_int(f_out, sum1);
 249                 write_buf(f_out, sum2, sum.s2length);
 250                 len -= n1;
 251                 offset += n1;
 252         }
 253 }
 254
 255
 256
 257 /**
 258  * Acts on file number @p i from @p flist, whose name is @p fname.
 259  *
 260  * First fixes up permissions, then generates checksums for the file.
 261  *
 262  * @note This comment was added later by mbp who was trying to work it
 263  * out.  It might be wrong.
 264  **/
 265 void recv_generator(char *fname, struct file_struct *file, int i, int f_out)
 266 {
 267         int fd;
 268         STRUCT_STAT st;
 269         struct map_struct *mapbuf;
 270         int statret;
 271         char *fnamecmp;
 272         char fnamecmpbuf[MAXPATHLEN];
 273         extern char *compare_dest;
 274         extern int list_only;
 275         extern int only_existing;
 276         extern int orig_umask;
 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                 extern int safe_symlinks;
 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,1);
 356                                         return;
 357                                 }
 358                         }
 359                         /* Not a symlink, so delete whatever's
 360                          * already there and put a new symlink
 361                          * in place. */
 362                         delete_file(fname);
 363                 }
 364                 if (do_symlink(file->u.link,fname) != 0) {
 365                         rprintf(FERROR, "symlink %s -> \"%s\" failed: %s\n",
 366                                 full_fname(fname), file->u.link, strerror(errno));
 367                 } else {
 368                         set_perms(fname,file,NULL,0);
 369                         if (verbose) {
 370                                 rprintf(FINFO,"%s -> %s\n", fname,file->u.link);
 371                         }
 372                 }
 373 #endif
 374                 return;
 375         }
 376
 377 #ifdef HAVE_MKNOD
 378         if (am_root && preserve_devices && IS_DEVICE(file->mode)) {
 379                 if (statret != 0 ||
 380                     st.st_mode != file->mode ||
 381                     st.st_rdev != file->u.rdev) {
 382                         delete_file(fname);
 383                         if (verbose > 2)
 384                                 rprintf(FINFO,"mknod(%s,0%o,0x%x)\n",
 385                                         fname,(int)file->mode,(int)file->u.rdev);
 386                         if (do_mknod(fname,file->mode,file->u.rdev) != 0) {
 387                                 rprintf(FERROR, "mknod %s failed: %s\n",
 388                                         full_fname(fname), strerror(errno));
 389                         } else {
 390                                 set_perms(fname,file,NULL,0);
 391                                 if (verbose)
 392                                         rprintf(FINFO,"%s\n",fname);
 393                         }
 394                 } else {
 395                         set_perms(fname,file,&st,1);
 396                 }
 397                 return;
 398         }
 399 #endif
 400
 401         if (preserve_hard_links && hard_link_check(file, HL_CHECK_MASTER))
 402                 return;
 403
 404         if (!S_ISREG(file->mode)) {
 405                 rprintf(FINFO, "skipping non-regular file \"%s\"\n",fname);
 406                 return;
 407         }
 408
 409         fnamecmp = fname;
 410
 411         if (statret == -1 && compare_dest != NULL) {
 412                 /* try the file at compare_dest instead */
 413                 int saveerrno = errno;
 414                 pathjoin(fnamecmpbuf, sizeof fnamecmpbuf, compare_dest, fname);
 415                 statret = link_stat(fnamecmpbuf,&st);
 416                 if (!S_ISREG(st.st_mode))
 417                         statret = -1;
 418                 if (statret == -1)
 419                         errno = saveerrno;
 420 #if HAVE_LINK
 421                 else if (link_dest && !dry_run) {
 422                         if (do_link(fnamecmpbuf, fname) != 0) {
 423                                 if (verbose > 0) {
 424                                         rprintf(FINFO,"link %s => %s : %s\n",
 425                                                 fnamecmpbuf, fname,
 426                                                 strerror(errno));
 427                                 }
 428                         }
 429                         fnamecmp = fnamecmpbuf;
 430                 }
 431 #endif
 432                 else
 433                         fnamecmp = fnamecmpbuf;
 434         }
 435
 436         if (statret == -1) {
 437                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 438                         return;
 439                 if (errno == ENOENT) {
 440                         write_int(f_out,i);
 441                         if (!dry_run) write_sum_head(f_out, NULL);
 442                 } else if (verbose > 1) {
 443                         rprintf(FERROR,
 444                                 "recv_generator: failed to open %s: %s\n",
 445                                 full_fname(fname), strerror(errno));
 446                 }
 447                 return;
 448         }
 449
 450         if (!S_ISREG(st.st_mode)) {
 451                 if (delete_file(fname) != 0) {
 452                         return;
 453                 }
 454
 455                 /* now pretend the file didn't exist */
 456                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 457                         return;
 458                 write_int(f_out,i);
 459                 if (!dry_run) write_sum_head(f_out, NULL);
 460                 return;
 461         }
 462
 463         if (opt_ignore_existing && fnamecmp == fname) {
 464                 if (verbose > 1)
 465                         rprintf(FINFO,"%s exists\n",fname);
 466                 return;
 467         }
 468
 469         if (update_only && cmp_modtime(st.st_mtime,file->modtime)>0 && fnamecmp == fname) {
 470                 if (verbose > 1)
 471                         rprintf(FINFO,"%s is newer\n",fname);
 472                 return;
 473         }
 474
 475         if (skip_file(fname, file, &st)) {
 476                 if (fnamecmp == fname)
 477                         set_perms(fname,file,&st,1);
 478                 return;
 479         }
 480
 481         if (dry_run) {
 482                 write_int(f_out,i);
 483                 return;
 484         }
 485
 486         if (disable_deltas_p()) {
 487                 write_int(f_out,i);
 488                 write_sum_head(f_out, NULL);
 489                 return;
 490         }
 491
 492         /* open the file */
 493         fd = do_open(fnamecmp, O_RDONLY, 0);
 494
 495         if (fd == -1) {
 496                 rprintf(FERROR, "failed to open %s, continuing: %s\n",
 497                         full_fname(fnamecmp), strerror(errno));
 498                 /* pretend the file didn't exist */
 499                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 500                         return;
 501                 write_int(f_out,i);
 502                 write_sum_head(f_out, NULL);
 503                 return;
 504         }
 505
 506         if (st.st_size > 0)
 507                 mapbuf = map_file(fd,st.st_size);
 508         else
 509                 mapbuf = NULL;
 510
 511         if (verbose > 3) {
 512                 rprintf(FINFO,"gen mapped %s of size %.0f\n", fnamecmp,
 513                         (double)st.st_size);
 514         }
 515
 516         if (verbose > 2)
 517                 rprintf(FINFO, "generating and sending sums for %d\n", i);
 518
 519         write_int(f_out,i);
 520         generate_and_send_sums(mapbuf, st.st_size, f_out);
 521
 522         close(fd);
 523         if (mapbuf) unmap_file(mapbuf);
 524 }
 525
 526
 527 void generate_files(int f, struct file_list *flist, char *local_name)
 528 {
 529         int i;
 530         int phase=0;
 531         char fbuf[MAXPATHLEN];
 532
 533         if (verbose > 2) {
 534                 rprintf(FINFO, "generator starting pid=%ld count=%d\n",
 535                         (long)getpid(), flist->count);
 536         }
 537
 538         if (verbose >= 2) {
 539                 rprintf(FINFO,
 540                         disable_deltas_p()
 541                         ? "delta-transmission disabled for local transfer or --whole-file\n"
 542                         : "delta transmission enabled\n");
 543         }
 544
 545         /* we expect to just sit around now, so don't exit on a
 546            timeout. If we really get a timeout then the other process should
 547            exit */
 548         io_timeout = 0;
 549
 550         for (i = 0; i < flist->count; i++) {
 551                 struct file_struct *file = flist->files[i];
 552                 struct file_struct copy;
 553
 554                 if (!file->basename)
 555                         continue;
 556                 /* we need to ensure that any directories we create have writeable
 557                    permissions initially so that we can create the files within
 558                    them. This is then fixed after the files are transferred */
 559                 if (!am_root && S_ISDIR(file->mode) && !(file->mode & S_IWUSR)) {
 560                         copy = *file;
 561                         /* XXX: Could this be causing a problem on SCO?  Perhaps their
 562                          * handling of permissions is strange? */
 563                         copy.mode |= S_IWUSR; /* user write */
 564                         file = &copy;
 565                 }
 566
 567                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 568                                file, i, f);
 569         }
 570
 571         phase++;
 572         csum_length = SUM_LENGTH;
 573         ignore_times=1;
 574
 575         if (verbose > 2)
 576                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 577
 578         write_int(f,-1);
 579
 580         /* files can cycle through the system more than once
 581          * to catch initial checksum errors */
 582         while ((i = get_redo_num()) != -1) {
 583                 struct file_struct *file = flist->files[i];
 584                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 585                                file, i, f);
 586         }
 587
 588         phase++;
 589         if (verbose > 2)
 590                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 591
 592         write_int(f,-1);
 593
 594         if (preserve_hard_links)
 595                 do_hard_links();
 596
 597         /* now we need to fix any directory permissions that were
 598          * modified during the transfer */
 599         for (i = 0; i < flist->count; i++) {
 600                 struct file_struct *file = flist->files[i];
 601                 if (!file->basename || !S_ISDIR(file->mode)) continue;
 602                 recv_generator(local_name ? local_name : f_name(file),
 603                                file, i, -1);
 604         }
 605
 606         if (verbose > 2)
 607                 rprintf(FINFO,"generate_files finished\n");
 608 }