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 write_batch;
  49 extern int list_only;
  50 extern int only_existing;
  51 extern int orig_umask;
  52 extern int safe_symlinks;
  53
  54
  55 /* choose whether to skip a particular file */
  56 static int skip_file(char *fname, struct file_struct *file, STRUCT_STAT *st)
  57 {
  58         if (st->st_size != file->length) {
  59                 return 0;
  60         }
  61         if (link_dest) {
  62                 if (preserve_perms
  63                     && (st->st_mode & CHMOD_BITS) != (file->mode & CHMOD_BITS))
  64                         return 0;
  65
  66                 if (am_root && preserve_uid && st->st_uid != file->uid)
  67                         return 0;
  68
  69                 if (preserve_gid && file->gid != GID_NONE
  70                     && st->st_gid != file->gid)
  71                         return 0;
  72         }
  73
  74         /* if always checksum is set then we use the checksum instead
  75            of the file time to determine whether to sync */
  76         if (always_checksum && S_ISREG(st->st_mode)) {
  77                 char sum[MD4_SUM_LENGTH];
  78                 char fnamecmpdest[MAXPATHLEN];
  79
  80                 if (compare_dest != NULL) {
  81                         if (access(fname, 0) != 0) {
  82                                 pathjoin(fnamecmpdest, sizeof fnamecmpdest,
  83                                          compare_dest, fname);
  84                                 fname = fnamecmpdest;
  85                         }
  86                 }
  87                 file_checksum(fname,sum,st->st_size);
  88                 return memcmp(sum, file->u.sum, protocol_version < 21 ? 2
  89                                                         : MD4_SUM_LENGTH) == 0;
  90         }
  91
  92         if (size_only) {
  93                 return 1;
  94         }
  95
  96         if (ignore_times) {
  97                 return 0;
  98         }
  99
 100         return (cmp_modtime(st->st_mtime,file->modtime) == 0);
 101 }
 102
 103
 104 /*
 105  * NULL sum_struct means we have no checksums
 106  */
 107 void write_sum_head(int f, struct sum_struct *sum)
 108 {
 109         static struct sum_struct null_sum;
 110
 111         if (sum == NULL)
 112                 sum = &null_sum;
 113
 114         write_int(f, sum->count);
 115         write_int(f, sum->blength);
 116         if (protocol_version >= 27)
 117                 write_int(f, sum->s2length);
 118         write_int(f, sum->remainder);
 119 }
 120
 121 /*
 122  * set (initialize) the size entries in the per-file sum_struct
 123  * calulating dynamic block ans checksum sizes.
 124  *
 125  * This is only called from generate_and_send_sums() but is a seperate
 126  * function to encapsulate the logic.
 127  *
 128  * The block size is a rounded square root of file length.
 129  *
 130  * The checksum size is determined according to:
 131  *     blocksum_bits = BLOCKSUM_EXP + 2*log2(file_len) - log2(block_len)
 132  * provided by Donovan Baarda which gives a probability of rsync
 133  * algorithm corrupting data and falling back using the whole md4
 134  * checksums.
 135  *
 136  * This might be made one of several selectable heuristics.
 137  */
 138
 139 static void sum_sizes_sqroot(struct sum_struct *sum, uint64 len)
 140 {
 141         extern unsigned int block_size;
 142         unsigned int blength;
 143         int s2length;
 144         uint32 c;
 145         uint64 l;
 146
 147         if (block_size) {
 148                 blength = block_size;
 149         } else if (len <= BLOCK_SIZE * BLOCK_SIZE) {
 150                 blength = BLOCK_SIZE;
 151         } else {
 152                 l = len;
 153                 c = 1;
 154                 while (l >>= 2) {
 155                         c <<= 1;
 156                 }
 157                 blength = 0;
 158                 do {
 159                         blength |= c;
 160                         if (len < (uint64)blength * blength)
 161                                 blength &= ~c;
 162                         c >>= 1;
 163                 } while (c >= 8);       /* round to multiple of 8 */
 164                 blength = MAX(blength, BLOCK_SIZE);
 165         }
 166
 167         if (protocol_version < 27) {
 168                 s2length = csum_length;
 169         } else if (csum_length == SUM_LENGTH) {
 170                 s2length = SUM_LENGTH;
 171         } else {
 172                 int b = BLOCKSUM_BIAS;
 173                 l = len;
 174                 while (l >>= 1) {
 175                         b += 2;
 176                 }
 177                 c = blength;
 178                 while (c >>= 1 && b) {
 179                         b--;
 180                 }
 181                 s2length = (b + 1 - 32 + 7) / 8; /* add a bit,
 182                                                   * subtract rollsum,
 183                                                   * round up
 184                                                   *    --optimize in compiler--
 185                                                   */
 186                 s2length = MAX(s2length, csum_length);
 187                 s2length = MIN(s2length, SUM_LENGTH);
 188         }
 189
 190         sum->flength    = len;
 191         sum->blength    = blength;
 192         sum->s2length   = s2length;
 193         sum->count      = (len + (blength - 1)) / blength;
 194         sum->remainder  = (len % blength);
 195
 196         if (sum->count && verbose > 2) {
 197                 rprintf(FINFO, "count=%.0f rem=%u blength=%u s2length=%d flength=%.0f\n",
 198                         (double)sum->count, sum->remainder, sum->blength,
 199                         sum->s2length, (double)sum->flength);
 200         }
 201 }
 202
 203 /**
 204  * Perhaps we want to just send an empty checksum set for this file,
 205  * which will force the whole thing to be literally transferred.
 206  *
 207  * When do we do this?  If the user's explicitly said they
 208  * want the whole thing, or if { they haven't explicitly
 209  * requested a delta, and it's local but not batch mode.}
 210  *
 211  * Whew. */
 212 static BOOL disable_deltas_p(void)
 213 {
 214         if (whole_file > 0)
 215                 return True;
 216         if (whole_file == 0 || write_batch)
 217                 return False;
 218         return local_server;
 219 }
 220
 221
 222 /*
 223  * Generate and send a stream of signatures/checksums that describe a buffer
 224  *
 225  * Generate approximately one checksum every block_len bytes.
 226  */
 227 static void generate_and_send_sums(struct map_struct *buf, size_t len, int f_out)
 228 {
 229         size_t i;
 230         struct sum_struct sum;
 231         OFF_T offset = 0;
 232
 233         sum_sizes_sqroot(&sum, len);
 234
 235         write_sum_head(f_out, &sum);
 236
 237         for (i = 0; i < sum.count; i++) {
 238                 unsigned int n1 = MIN(len, sum.blength);
 239                 char *map = map_ptr(buf, offset, n1);
 240                 uint32 sum1 = get_checksum1(map, n1);
 241                 char sum2[SUM_LENGTH];
 242
 243                 get_checksum2(map, n1, sum2);
 244
 245                 if (verbose > 3) {
 246                         rprintf(FINFO,
 247                                 "chunk[%.0f] offset=%.0f len=%u sum1=%08lx\n",
 248                                 (double)i, (double)offset, n1,
 249                                 (unsigned long)sum1);
 250                 }
 251                 write_int(f_out, sum1);
 252                 write_buf(f_out, sum2, sum.s2length);
 253                 len -= n1;
 254                 offset += n1;
 255         }
 256 }
 257
 258
 259
 260 /**
 261  * Acts on file number @p i from @p flist, whose name is @p fname.
 262  *
 263  * First fixes up permissions, then generates checksums for the file.
 264  *
 265  * @note This comment was added later by mbp who was trying to work it
 266  * out.  It might be wrong.
 267  **/
 268 void recv_generator(char *fname, struct file_struct *file, int i, int f_out)
 269 {
 270         int fd;
 271         STRUCT_STAT st;
 272         struct map_struct *mapbuf;
 273         int statret;
 274         char *fnamecmp;
 275         char fnamecmpbuf[MAXPATHLEN];
 276
 277         if (list_only)
 278                 return;
 279
 280         if (verbose > 2)
 281                 rprintf(FINFO,"recv_generator(%s,%d)\n",fname,i);
 282
 283         statret = link_stat(fname,&st);
 284
 285         if (only_existing && statret == -1 && errno == ENOENT) {
 286                 /* we only want to update existing files */
 287                 if (verbose > 1) rprintf(FINFO, "not creating new file \"%s\"\n",fname);
 288                 return;
 289         }
 290
 291         if (statret == 0 &&
 292             !preserve_perms &&
 293             (S_ISDIR(st.st_mode) == S_ISDIR(file->mode))) {
 294                 /* if the file exists already and we aren't perserving
 295                  * permissions then act as though the remote end sent
 296                  * us the file permissions we already have */
 297                 file->mode = (file->mode & ~CHMOD_BITS)
 298                            | (st.st_mode & CHMOD_BITS);
 299         }
 300
 301         if (S_ISDIR(file->mode)) {
 302                 /* The file to be received is a directory, so we need
 303                  * to prepare appropriately.  If there is already a
 304                  * file of that name and it is *not* a directory, then
 305                  * we need to delete it.  If it doesn't exist, then
 306                  * recursively create it. */
 307
 308                 if (dry_run) return; /* XXXX -- might cause inaccuracies?? -- mbp */
 309                 if (statret == 0 && !S_ISDIR(st.st_mode)) {
 310                         if (robust_unlink(fname) != 0) {
 311                                 rprintf(FERROR,
 312                                         "recv_generator: unlink %s to make room for directory: %s\n",
 313                                         full_fname(fname), strerror(errno));
 314                                 return;
 315                         }
 316                         statret = -1;
 317                 }
 318                 if (statret != 0 && do_mkdir(fname,file->mode) != 0 && errno != EEXIST) {
 319                         if (!(relative_paths && errno==ENOENT &&
 320                               create_directory_path(fname, orig_umask)==0 &&
 321                               do_mkdir(fname,file->mode)==0)) {
 322                                 rprintf(FERROR, "recv_generator: mkdir %s failed: %s\n",
 323                                         full_fname(fname), strerror(errno));
 324                         }
 325                 }
 326                 /* f_out is set to -1 when doing final directory
 327                    permission and modification time repair */
 328                 if (set_perms(fname,file,NULL,0) && verbose && (f_out != -1))
 329                         rprintf(FINFO,"%s/\n",fname);
 330                 return;
 331         }
 332
 333         if (preserve_links && S_ISLNK(file->mode)) {
 334 #if SUPPORT_LINKS
 335                 char lnk[MAXPATHLEN];
 336                 int l;
 337
 338                 if (safe_symlinks && unsafe_symlink(file->u.link, fname)) {
 339                         if (verbose) {
 340                                 rprintf(FINFO, "ignoring unsafe symlink %s -> \"%s\"\n",
 341                                         full_fname(fname), file->u.link);
 342                         }
 343                         return;
 344                 }
 345                 if (statret == 0) {
 346                         l = readlink(fname,lnk,MAXPATHLEN-1);
 347                         if (l > 0) {
 348                                 lnk[l] = 0;
 349                                 /* A link already pointing to the
 350                                  * right place -- no further action
 351                                  * required. */
 352                                 if (strcmp(lnk,file->u.link) == 0) {
 353                                         set_perms(fname,file,&st,1);
 354                                         return;
 355                                 }
 356                         }
 357                         /* Not a symlink, so delete whatever's
 358                          * already there and put a new symlink
 359                          * in place. */
 360                         delete_file(fname);
 361                 }
 362                 if (do_symlink(file->u.link,fname) != 0) {
 363                         rprintf(FERROR, "symlink %s -> \"%s\" failed: %s\n",
 364                                 full_fname(fname), file->u.link, strerror(errno));
 365                 } else {
 366                         set_perms(fname,file,NULL,0);
 367                         if (verbose) {
 368                                 rprintf(FINFO,"%s -> %s\n", fname,file->u.link);
 369                         }
 370                 }
 371 #endif
 372                 return;
 373         }
 374
 375 #ifdef HAVE_MKNOD
 376         if (am_root && preserve_devices && IS_DEVICE(file->mode)) {
 377                 if (statret != 0 ||
 378                     st.st_mode != file->mode ||
 379                     st.st_rdev != file->u.rdev) {
 380                         delete_file(fname);
 381                         if (verbose > 2)
 382                                 rprintf(FINFO,"mknod(%s,0%o,0x%x)\n",
 383                                         fname,(int)file->mode,(int)file->u.rdev);
 384                         if (do_mknod(fname,file->mode,file->u.rdev) != 0) {
 385                                 rprintf(FERROR, "mknod %s failed: %s\n",
 386                                         full_fname(fname), strerror(errno));
 387                         } else {
 388                                 set_perms(fname,file,NULL,0);
 389                                 if (verbose)
 390                                         rprintf(FINFO,"%s\n",fname);
 391                         }
 392                 } else {
 393                         set_perms(fname,file,&st,1);
 394                 }
 395                 return;
 396         }
 397 #endif
 398
 399         if (preserve_hard_links && hard_link_check(file, HL_CHECK_MASTER))
 400                 return;
 401
 402         if (!S_ISREG(file->mode)) {
 403                 rprintf(FINFO, "skipping non-regular file \"%s\"\n",fname);
 404                 return;
 405         }
 406
 407         fnamecmp = fname;
 408
 409         if (statret == -1 && compare_dest != NULL) {
 410                 /* try the file at compare_dest instead */
 411                 int saveerrno = errno;
 412                 pathjoin(fnamecmpbuf, sizeof fnamecmpbuf, compare_dest, fname);
 413                 statret = link_stat(fnamecmpbuf,&st);
 414                 if (!S_ISREG(st.st_mode))
 415                         statret = -1;
 416                 if (statret == -1)
 417                         errno = saveerrno;
 418 #if HAVE_LINK
 419                 else if (link_dest && !dry_run) {
 420                         if (do_link(fnamecmpbuf, fname) != 0) {
 421                                 if (verbose > 0) {
 422                                         rprintf(FINFO,"link %s => %s : %s\n",
 423                                                 fnamecmpbuf, fname,
 424                                                 strerror(errno));
 425                                 }
 426                         }
 427                         fnamecmp = fnamecmpbuf;
 428                 }
 429 #endif
 430                 else
 431                         fnamecmp = fnamecmpbuf;
 432         }
 433
 434         if (statret == -1) {
 435                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 436                         return;
 437                 if (errno == ENOENT) {
 438                         write_int(f_out,i);
 439                         if (!dry_run) write_sum_head(f_out, NULL);
 440                 } else if (verbose > 1) {
 441                         rprintf(FERROR,
 442                                 "recv_generator: failed to open %s: %s\n",
 443                                 full_fname(fname), strerror(errno));
 444                 }
 445                 return;
 446         }
 447
 448         if (!S_ISREG(st.st_mode)) {
 449                 if (delete_file(fname) != 0) {
 450                         return;
 451                 }
 452
 453                 /* now pretend the file didn't exist */
 454                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 455                         return;
 456                 write_int(f_out,i);
 457                 if (!dry_run) write_sum_head(f_out, NULL);
 458                 return;
 459         }
 460
 461         if (opt_ignore_existing && fnamecmp == fname) {
 462                 if (verbose > 1)
 463                         rprintf(FINFO,"%s exists\n",fname);
 464                 return;
 465         }
 466
 467         if (update_only && cmp_modtime(st.st_mtime,file->modtime)>0 && fnamecmp == fname) {
 468                 if (verbose > 1)
 469                         rprintf(FINFO,"%s is newer\n",fname);
 470                 return;
 471         }
 472
 473         if (skip_file(fname, file, &st)) {
 474                 if (fnamecmp == fname)
 475                         set_perms(fname,file,&st,1);
 476                 return;
 477         }
 478
 479         if (dry_run) {
 480                 write_int(f_out,i);
 481                 return;
 482         }
 483
 484         if (disable_deltas_p()) {
 485                 write_int(f_out,i);
 486                 write_sum_head(f_out, NULL);
 487                 return;
 488         }
 489
 490         /* open the file */
 491         fd = do_open(fnamecmp, O_RDONLY, 0);
 492
 493         if (fd == -1) {
 494                 rprintf(FERROR, "failed to open %s, continuing: %s\n",
 495                         full_fname(fnamecmp), strerror(errno));
 496                 /* pretend the file didn't exist */
 497                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
 498                         return;
 499                 write_int(f_out,i);
 500                 write_sum_head(f_out, NULL);
 501                 return;
 502         }
 503
 504         if (st.st_size > 0)
 505                 mapbuf = map_file(fd,st.st_size);
 506         else
 507                 mapbuf = NULL;
 508
 509         if (verbose > 3) {
 510                 rprintf(FINFO,"gen mapped %s of size %.0f\n", fnamecmp,
 511                         (double)st.st_size);
 512         }
 513
 514         if (verbose > 2)
 515                 rprintf(FINFO, "generating and sending sums for %d\n", i);
 516
 517         write_int(f_out,i);
 518         generate_and_send_sums(mapbuf, st.st_size, f_out);
 519
 520         close(fd);
 521         if (mapbuf) unmap_file(mapbuf);
 522 }
 523
 524
 525 void generate_files(int f, struct file_list *flist, char *local_name)
 526 {
 527         int i;
 528         int phase=0;
 529         char fbuf[MAXPATHLEN];
 530
 531         if (verbose > 2) {
 532                 rprintf(FINFO, "generator starting pid=%ld count=%d\n",
 533                         (long)getpid(), flist->count);
 534         }
 535
 536         if (verbose >= 2) {
 537                 rprintf(FINFO,
 538                         disable_deltas_p()
 539                         ? "delta-transmission disabled for local transfer or --whole-file\n"
 540                         : "delta transmission enabled\n");
 541         }
 542
 543         /* we expect to just sit around now, so don't exit on a
 544            timeout. If we really get a timeout then the other process should
 545            exit */
 546         io_timeout = 0;
 547
 548         for (i = 0; i < flist->count; i++) {
 549                 struct file_struct *file = flist->files[i];
 550                 struct file_struct copy;
 551
 552                 if (!file->basename)
 553                         continue;
 554                 /* we need to ensure that any directories we create have writeable
 555                    permissions initially so that we can create the files within
 556                    them. This is then fixed after the files are transferred */
 557                 if (!am_root && S_ISDIR(file->mode) && !(file->mode & S_IWUSR)) {
 558                         copy = *file;
 559                         /* XXX: Could this be causing a problem on SCO?  Perhaps their
 560                          * handling of permissions is strange? */
 561                         copy.mode |= S_IWUSR; /* user write */
 562                         file = &copy;
 563                 }
 564
 565                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 566                                file, i, f);
 567         }
 568
 569         phase++;
 570         csum_length = SUM_LENGTH;
 571         ignore_times=1;
 572
 573         if (verbose > 2)
 574                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 575
 576         write_int(f,-1);
 577
 578         /* files can cycle through the system more than once
 579          * to catch initial checksum errors */
 580         while ((i = get_redo_num()) != -1) {
 581                 struct file_struct *file = flist->files[i];
 582                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 583                                file, i, f);
 584         }
 585
 586         phase++;
 587         if (verbose > 2)
 588                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 589
 590         write_int(f,-1);
 591
 592         if (preserve_hard_links)
 593                 do_hard_links();
 594
 595         /* now we need to fix any directory permissions that were
 596          * modified during the transfer */
 597         for (i = 0; i < flist->count; i++) {
 598                 struct file_struct *file = flist->files[i];
 599                 if (!file->basename || !S_ISDIR(file->mode)) continue;
 600                 recv_generator(local_name ? local_name : f_name(file),
 601                                file, i, -1);
 602         }
 603
 604         if (verbose > 2)
 605                 rprintf(FINFO,"generate_files finished\n");
 606 }