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 & ~_S_IFMT) != (file->mode & ~_S_IFMT))
  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                                 snprintf(fnamecmpdest,MAXPATHLEN,"%s/%s",
  76                                          compare_dest,fname);
  77                                 fname = fnamecmpdest;
  78                         }
  79                 }
  80                 file_checksum(fname,sum,st->st_size);
  81                 if (protocol_version < 21) {
  82                         return (memcmp(sum,file->sum,2) == 0);
  83                 } else {
  84                         return (memcmp(sum,file->sum,MD4_SUM_LENGTH) == 0);
  85                 }
  86         }
  87
  88         if (size_only) {
  89                 return 1;
  90         }
  91
  92         if (ignore_times) {
  93                 return 0;
  94         }
  95
  96         return (cmp_modtime(st->st_mtime,file->modtime) == 0);
  97 }
  98
  99
 100 /*
 101  * NULL sum_struct means we have no checksums
 102  */
 103 void write_sum_head(int f, struct sum_struct *sum)
 104 {
 105         static struct sum_struct null_sum;
 106
 107         if (sum == (struct sum_struct *)NULL)
 108                 sum = &null_sum;
 109
 110         write_int(f, sum->count);
 111         write_int(f, sum->blength);
 112         if (protocol_version >= 27)
 113                 write_int(f, sum->s2length);
 114         write_int(f, sum->remainder);
 115 }
 116
 117 /*
 118  * set (initialize) the size entries in the per-file sum_struct
 119  * calulating dynamic block ans checksum sizes.
 120  *
 121  * This is only called from generate_and_send_sums() but is a seperate
 122  * function to encapsulate the logic.
 123  *
 124  * The block size is a rounded square root of file length.
 125  *
 126  * The checksum size is determined according to:
 127  *     blocksum_bits = BLOCKSUM_EXP + 2*log2(file_len) - log2(block_len)
 128  * provided by Donovan Baarda which gives a probability of rsync
 129  * algorithm corrupting data and falling back using the whole md4
 130  * checksums.
 131  *
 132  * This might be made one of several selectable heuristics.
 133  */
 134
 135 static void sum_sizes_sqroot(struct sum_struct *sum, uint64 len)
 136 {
 137         extern unsigned int block_size;
 138         unsigned int blength;
 139         int s2length;
 140         uint32 c;
 141         uint64 l;
 142
 143         if (block_size) {
 144                 blength = block_size;
 145         } else if (len <= BLOCK_SIZE * BLOCK_SIZE) {
 146                 blength = BLOCK_SIZE;
 147         } else {
 148                 l = len;
 149                 c = 1;
 150                 while (l >>= 2) {
 151                         c <<= 1;
 152                 }
 153                 blength = 0;
 154                 do {
 155                         blength |= c;
 156                         if (len < (uint64)blength * blength)
 157                                 blength &= ~c;
 158                         c >>= 1;
 159                 } while (c >= 8);       /* round to multiple of 8 */
 160                 blength = MAX(blength, BLOCK_SIZE);
 161         }
 162
 163         if (protocol_version < 27) {
 164                 s2length = csum_length;
 165         } else if (csum_length == SUM_LENGTH) {
 166                 s2length = SUM_LENGTH;
 167         } else {
 168                 int b = BLOCKSUM_BIAS;
 169                 l = len;
 170                 while (l >>= 1) {
 171                         b += 2;
 172                 }
 173                 c = blength;
 174                 while (c >>= 1 && b) {
 175                         b--;
 176                 }
 177                 s2length = (b + 1 - 32 + 7) / 8; /* add a bit,
 178                                                   * subtract rollsum,
 179                                                   * round up
 180                                                   *    --optimize in compiler--
 181                                                   */
 182                 s2length = MAX(s2length, csum_length);
 183                 s2length = MIN(s2length, SUM_LENGTH);
 184         }
 185
 186         sum->flength    = len;
 187         sum->blength    = blength;
 188         sum->s2length   = s2length;
 189         sum->count      = (len + (blength - 1)) / blength;
 190         sum->remainder  = (len % blength);
 191
 192         if (sum->count && verbose > 2) {
 193                 rprintf(FINFO, "count=%.0f rem=%u blength=%u s2length=%d flength=%.0f\n",
 194                         (double)sum->count, sum->remainder, sum->blength,
 195                         sum->s2length, (double)sum->flength);
 196         }
 197 }
 198
 199 /**
 200  * Perhaps we want to just send an empty checksum set for this file,
 201  * which will force the whole thing to be literally transferred.
 202  *
 203  * When do we do this?  If the user's explicitly said they
 204  * want the whole thing, or if { they haven't explicitly
 205  * requested a delta, and it's local but not batch mode.}
 206  *
 207  * Whew. */
 208 static BOOL disable_deltas_p(void)
 209 {
 210         extern int whole_file;
 211         extern int local_server;
 212         extern int write_batch;
 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         extern char *compare_dest;
 277         extern int list_only;
 278         extern int only_existing;
 279         extern int orig_umask;
 280
 281         if (list_only)
 282                 return;
 283
 284         if (verbose > 2)
 285                 rprintf(FINFO,"recv_generator(%s,%d)\n",fname,i);
 286
 287         statret = link_stat(fname,&st);
 288
 289         if (only_existing && statret == -1 && errno == ENOENT) {
 290                 /* we only want to update existing files */
 291                 if (verbose > 1) rprintf(FINFO, "not creating new file \"%s\"\n",fname);
 292                 return;
 293         }
 294
 295         if (statret == 0 &&
 296             !preserve_perms &&
 297             (S_ISDIR(st.st_mode) == S_ISDIR(file->mode))) {
 298                 /* if the file exists already and we aren't perserving
 299                  * permissions then act as though the remote end sent
 300                  * us the file permissions we already have */
 301                 file->mode = (file->mode & _S_IFMT) | (st.st_mode & ~_S_IFMT);
 302         }
 303
 304         if (S_ISDIR(file->mode)) {
 305                 /* The file to be received is a directory, so we need
 306                  * to prepare appropriately.  If there is already a
 307                  * file of that name and it is *not* a directory, then
 308                  * we need to delete it.  If it doesn't exist, then
 309                  * recursively create it. */
 310
 311                 if (dry_run) return; /* XXXX -- might cause inaccuracies?? -- mbp */
 312                 if (statret == 0 && !S_ISDIR(st.st_mode)) {
 313                         if (robust_unlink(fname) != 0) {
 314                                 rprintf(FERROR,
 315                                         "recv_generator: unlink %s to make room for directory: %s\n",
 316                                         full_fname(fname), strerror(errno));
 317                                 return;
 318                         }
 319                         statret = -1;
 320                 }
 321                 if (statret != 0 && do_mkdir(fname,file->mode) != 0 && errno != EEXIST) {
 322                         if (!(relative_paths && errno==ENOENT &&
 323                               create_directory_path(fname, orig_umask)==0 &&
 324                               do_mkdir(fname,file->mode)==0)) {
 325                                 rprintf(FERROR, "recv_generator: mkdir %s failed: %s\n",
 326                                         full_fname(fname), strerror(errno));
 327                         }
 328                 }
 329                 /* f_out is set to -1 when doing final directory
 330                    permission and modification time repair */
 331                 if (set_perms(fname,file,NULL,0) && verbose && (f_out != -1))
 332                         rprintf(FINFO,"%s/\n",fname);
 333                 return;
 334         }
 335
 336         if (preserve_links && S_ISLNK(file->mode)) {
 337 #if SUPPORT_LINKS
 338                 char lnk[MAXPATHLEN];
 339                 int l;
 340                 extern int safe_symlinks;
 341
 342                 if (safe_symlinks && unsafe_symlink(file->link, fname)) {
 343                         if (verbose) {
 344                                 rprintf(FINFO, "ignoring unsafe symlink %s -> \"%s\"\n",
 345                                         full_fname(fname), file->link);
 346                         }
 347                         return;
 348                 }
 349                 if (statret == 0) {
 350                         l = readlink(fname,lnk,MAXPATHLEN-1);
 351                         if (l > 0) {
 352                                 lnk[l] = 0;
 353                                 /* A link already pointing to the
 354                                  * right place -- no further action
 355                                  * required. */
 356                                 if (strcmp(lnk,file->link) == 0) {
 357                                         set_perms(fname,file,&st,1);
 358                                         return;
 359                                 }
 360                         }
 361                         /* Not a symlink, so delete whatever's
 362                          * already there and put a new symlink
 363                          * in place. */
 364                         delete_file(fname);
 365                 }
 366                 if (do_symlink(file->link,fname) != 0) {
 367                         rprintf(FERROR, "symlink %s -> \"%s\" failed: %s\n",
 368                                 full_fname(fname), file->link, strerror(errno));
 369                 } else {
 370                         set_perms(fname,file,NULL,0);
 371                         if (verbose) {
 372                                 rprintf(FINFO,"%s -> %s\n", fname,file->link);
 373                         }
 374                 }
 375 #endif
 376                 return;
 377         }
 378
 379 #ifdef HAVE_MKNOD
 380         if (am_root && preserve_devices && IS_DEVICE(file->mode)) {
 381                 if (statret != 0 ||
 382                     st.st_mode != file->mode ||
 383                     (DEV64_T)st.st_rdev != file->rdev) {
 384                         delete_file(fname);
 385                         if (verbose > 2)
 386                                 rprintf(FINFO,"mknod(%s,0%o,0x%x)\n",
 387                                         fname,(int)file->mode,(int)file->rdev);
 388                         if (do_mknod(fname,file->mode,file->rdev) != 0) {
 389                                 rprintf(FERROR, "mknod %s failed: %s\n",
 390                                         full_fname(fname), strerror(errno));
 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,1);
 398                 }
 399                 return;
 400         }
 401 #endif
 402
 403         if (preserve_hard_links && check_hard_link(file)) {
 404                 if (verbose > 1) {
 405                         rprintf(FINFO, "recv_generator: \"%s\" is a hard link\n",
 406                                 f_name(file));
 407                 }
 408                 return;
 409         }
 410
 411         if (!S_ISREG(file->mode)) {
 412                 rprintf(FINFO, "skipping non-regular file \"%s\"\n",fname);
 413                 return;
 414         }
 415
 416         fnamecmp = fname;
 417
 418         if ((statret == -1) && (compare_dest != NULL)) {
 419                 /* try the file at compare_dest instead */
 420                 int saveerrno = errno;
 421                 snprintf(fnamecmpbuf,MAXPATHLEN,"%s/%s",compare_dest,fname);
 422                 statret = link_stat(fnamecmpbuf,&st);
 423                 if (!S_ISREG(st.st_mode))
 424                         statret = -1;
 425                 if (statret == -1)
 426                         errno = saveerrno;
 427 #if HAVE_LINK
 428                 else if (link_dest && !dry_run) {
 429                         if (do_link(fnamecmpbuf, fname) != 0) {
 430                                 if (verbose > 0) {
 431                                         rprintf(FINFO,"link %s => %s : %s\n",
 432                                                 fnamecmpbuf, fname,
 433                                                 strerror(errno));
 434                                 }
 435                         }
 436                         fnamecmp = fnamecmpbuf;
 437                 }
 438 #endif
 439                 else
 440                         fnamecmp = fnamecmpbuf;
 441         }
 442
 443         if (statret == -1) {
 444                 if (errno == ENOENT) {
 445                         write_int(f_out,i);
 446                         if (!dry_run) write_sum_head(f_out, NULL);
 447                 } else if (verbose > 1) {
 448                         rprintf(FERROR,
 449                                 "recv_generator: failed to open %s: %s\n",
 450                                 full_fname(fname), strerror(errno));
 451                 }
 452                 return;
 453         }
 454
 455         if (!S_ISREG(st.st_mode)) {
 456                 if (delete_file(fname) != 0) {
 457                         return;
 458                 }
 459
 460                 /* now pretend the file didn't exist */
 461                 write_int(f_out,i);
 462                 if (!dry_run) write_sum_head(f_out, NULL);
 463                 return;
 464         }
 465
 466         if (opt_ignore_existing && fnamecmp == fname) {
 467                 if (verbose > 1)
 468                         rprintf(FINFO,"%s exists\n",fname);
 469                 return;
 470         }
 471
 472         if (update_only && cmp_modtime(st.st_mtime,file->modtime)>0 && fnamecmp == fname) {
 473                 if (verbose > 1)
 474                         rprintf(FINFO,"%s is newer\n",fname);
 475                 return;
 476         }
 477
 478         if (skip_file(fname, file, &st)) {
 479                 if (fnamecmp == fname)
 480                         set_perms(fname,file,&st,1);
 481                 return;
 482         }
 483
 484         if (dry_run) {
 485                 write_int(f_out,i);
 486                 return;
 487         }
 488
 489         if (disable_deltas_p()) {
 490                 write_int(f_out,i);
 491                 write_sum_head(f_out, NULL);
 492                 return;
 493         }
 494
 495         /* open the file */
 496         fd = do_open(fnamecmp, O_RDONLY, 0);
 497
 498         if (fd == -1) {
 499                 rprintf(FERROR, "failed to open %s, continuing: %s\n",
 500                         full_fname(fnamecmp), strerror(errno));
 501                 /* pretend the file didn't exist */
 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
 529 void generate_files(int f,struct file_list *flist,char *local_name,int f_recv)
 530 {
 531         int i;
 532         int phase=0;
 533         char fbuf[MAXPATHLEN];
 534
 535         if (verbose > 2)
 536                 rprintf(FINFO,"generator starting pid=%d count=%d\n",
 537                         (int)getpid(),flist->count);
 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
 569                              : f_name_to(file,fbuf,sizeof fbuf), 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         for (i = read_int(f_recv); i != -1; i = read_int(f_recv)) {
 584                 struct file_struct *file = flist->files[i];
 585                 recv_generator(local_name? local_name
 586                              : f_name_to(file,fbuf,sizeof fbuf), 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 }