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                                 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 == (struct sum_struct *)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 & _S_IFMT) | (st.st_mode & ~_S_IFMT);
 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                 extern int safe_symlinks;
 338
 339                 if (safe_symlinks && unsafe_symlink(file->u.link, fname)) {
 340                         if (verbose) {
 341                                 rprintf(FINFO, "ignoring unsafe symlink %s -> \"%s\"\n",
 342                                         full_fname(fname), file->u.link);
 343                         }
 344                         return;
 345                 }
 346                 if (statret == 0) {
 347                         l = readlink(fname,lnk,MAXPATHLEN-1);
 348                         if (l > 0) {
 349                                 lnk[l] = 0;
 350                                 /* A link already pointing to the
 351                                  * right place -- no further action
 352                                  * required. */
 353                                 if (strcmp(lnk,file->u.link) == 0) {
 354                                         set_perms(fname,file,&st,1);
 355                                         return;
 356                                 }
 357                         }
 358                         /* Not a symlink, so delete whatever's
 359                          * already there and put a new symlink
 360                          * in place. */
 361                         delete_file(fname);
 362                 }
 363                 if (do_symlink(file->u.link,fname) != 0) {
 364                         rprintf(FERROR, "symlink %s -> \"%s\" failed: %s\n",
 365                                 full_fname(fname), file->u.link, strerror(errno));
 366                 } else {
 367                         set_perms(fname,file,NULL,0);
 368                         if (verbose) {
 369                                 rprintf(FINFO,"%s -> %s\n", fname,file->u.link);
 370                         }
 371                 }
 372 #endif
 373                 return;
 374         }
 375
 376 #ifdef HAVE_MKNOD
 377         if (am_root && preserve_devices && IS_DEVICE(file->mode)) {
 378                 if (statret != 0 ||
 379                     st.st_mode != file->mode ||
 380                     (DEV64_T)st.st_rdev != file->u.rdev) {
 381                         delete_file(fname);
 382                         if (verbose > 2)
 383                                 rprintf(FINFO,"mknod(%s,0%o,0x%x)\n",
 384                                         fname,(int)file->mode,(int)file->u.rdev);
 385                         if (do_mknod(fname,file->mode,file->u.rdev) != 0) {
 386                                 rprintf(FERROR, "mknod %s failed: %s\n",
 387                                         full_fname(fname), strerror(errno));
 388                         } else {
 389                                 set_perms(fname,file,NULL,0);
 390                                 if (verbose)
 391                                         rprintf(FINFO,"%s\n",fname);
 392                         }
 393                 } else {
 394                         set_perms(fname,file,&st,1);
 395                 }
 396                 return;
 397         }
 398 #endif
 399
 400         if (preserve_hard_links && file->link_u.links && file->F_HEAD != file) {
 401                 if (verbose > 1) {
 402                         rprintf(FINFO, "recv_generator: \"%s\" is a hard link\n",
 403                                 f_name(file));
 404                 }
 405                 return;
 406         }
 407
 408         if (!S_ISREG(file->mode)) {
 409                 rprintf(FINFO, "skipping non-regular file \"%s\"\n",fname);
 410                 return;
 411         }
 412
 413         fnamecmp = fname;
 414
 415         if ((statret == -1) && (compare_dest != NULL)) {
 416                 /* try the file at compare_dest instead */
 417                 int saveerrno = errno;
 418                 pathjoin(fnamecmpbuf, sizeof fnamecmpbuf, compare_dest, fname);
 419                 statret = link_stat(fnamecmpbuf,&st);
 420                 if (!S_ISREG(st.st_mode))
 421                         statret = -1;
 422                 if (statret == -1)
 423                         errno = saveerrno;
 424 #if HAVE_LINK
 425                 else if (link_dest && !dry_run) {
 426                         if (do_link(fnamecmpbuf, fname) != 0) {
 427                                 if (verbose > 0) {
 428                                         rprintf(FINFO,"link %s => %s : %s\n",
 429                                                 fnamecmpbuf, fname,
 430                                                 strerror(errno));
 431                                 }
 432                         }
 433                         fnamecmp = fnamecmpbuf;
 434                 }
 435 #endif
 436                 else
 437                         fnamecmp = fnamecmpbuf;
 438         }
 439
 440         if (statret == -1) {
 441                 if (errno == ENOENT) {
 442                         write_int(f_out,i);
 443                         if (!dry_run) write_sum_head(f_out, NULL);
 444                 } else if (verbose > 1) {
 445                         rprintf(FERROR,
 446                                 "recv_generator: failed to open %s: %s\n",
 447                                 full_fname(fname), strerror(errno));
 448                 }
 449                 return;
 450         }
 451
 452         if (!S_ISREG(st.st_mode)) {
 453                 if (delete_file(fname) != 0) {
 454                         return;
 455                 }
 456
 457                 /* now pretend the file didn't exist */
 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                 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=%d count=%d\n",
 533                         (int)getpid(),flist->count);
 534
 535         if (verbose >= 2) {
 536                 rprintf(FINFO,
 537                         disable_deltas_p()
 538                         ? "delta-transmission disabled for local transfer or --whole-file\n"
 539                         : "delta transmission enabled\n");
 540         }
 541
 542         /* we expect to just sit around now, so don't exit on a
 543            timeout. If we really get a timeout then the other process should
 544            exit */
 545         io_timeout = 0;
 546
 547         for (i = 0; i < flist->count; i++) {
 548                 struct file_struct *file = flist->files[i];
 549                 struct file_struct copy;
 550
 551                 if (!file->basename)
 552                         continue;
 553                 /* we need to ensure that any directories we create have writeable
 554                    permissions initially so that we can create the files within
 555                    them. This is then fixed after the files are transferred */
 556                 if (!am_root && S_ISDIR(file->mode) && !(file->mode & S_IWUSR)) {
 557                         copy = *file;
 558                         /* XXX: Could this be causing a problem on SCO?  Perhaps their
 559                          * handling of permissions is strange? */
 560                         copy.mode |= S_IWUSR; /* user write */
 561                         file = &copy;
 562                 }
 563
 564                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 565                                file, i, f);
 566         }
 567
 568         phase++;
 569         csum_length = SUM_LENGTH;
 570         ignore_times=1;
 571
 572         if (verbose > 2)
 573                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 574
 575         write_int(f,-1);
 576
 577         /* files can cycle through the system more than once
 578          * to catch initial checksum errors */
 579         while ((i = get_redo_num()) != -1) {
 580                 struct file_struct *file = flist->files[i];
 581                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
 582                                file, i, f);
 583         }
 584
 585         phase++;
 586         if (verbose > 2)
 587                 rprintf(FINFO,"generate_files phase=%d\n",phase);
 588
 589         write_int(f,-1);
 590 }