Optimized away a call to cmp_modtime() for a compare-dest file.
[rsync.git] / 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 keep_dirlinks;
30 extern int preserve_links;
31 extern int am_root;
32 extern int preserve_devices;
33 extern int preserve_hard_links;
34 extern int preserve_perms;
35 extern int preserve_uid;
36 extern int preserve_gid;
37 extern int update_only;
38 extern int opt_ignore_existing;
39 extern int csum_length;
40 extern int ignore_times;
41 extern int size_only;
42 extern int io_timeout;
43 extern int protocol_version;
44 extern int always_checksum;
45 extern char *compare_dest;
46 extern int link_dest;
47 extern int whole_file;
48 extern int local_server;
49 extern int read_batch;
50 extern int write_batch;
51 extern int list_only;
52 extern int only_existing;
53 extern int orig_umask;
54 extern int safe_symlinks;
55 extern unsigned int block_size;
56
57 extern struct exclude_list_struct server_exclude_list;
58
59
60 /* choose whether to skip a particular file */
61 static int skip_file(char *fname, struct file_struct *file, STRUCT_STAT *st)
62 {
63         if (st->st_size != file->length)
64                 return 0;
65         if (link_dest) {
66                 if (preserve_perms
67                     && (st->st_mode & CHMOD_BITS) != (file->mode & CHMOD_BITS))
68                         return 0;
69
70                 if (am_root && preserve_uid && st->st_uid != file->uid)
71                         return 0;
72
73                 if (preserve_gid && file->gid != GID_NONE
74                     && st->st_gid != file->gid)
75                         return 0;
76         }
77
78         /* if always checksum is set then we use the checksum instead
79            of the file time to determine whether to sync */
80         if (always_checksum && S_ISREG(st->st_mode)) {
81                 char sum[MD4_SUM_LENGTH];
82                 char fnamecmpdest[MAXPATHLEN];
83
84                 if (compare_dest != NULL) {
85                         if (access(fname, 0) != 0) {
86                                 pathjoin(fnamecmpdest, sizeof fnamecmpdest,
87                                          compare_dest, fname);
88                                 fname = fnamecmpdest;
89                         }
90                 }
91                 file_checksum(fname,sum,st->st_size);
92                 return memcmp(sum, file->u.sum, protocol_version < 21 ? 2
93                                                         : MD4_SUM_LENGTH) == 0;
94         }
95
96         if (size_only)
97                 return 1;
98
99         if (ignore_times)
100                 return 0;
101
102         return cmp_modtime(st->st_mtime, file->modtime) == 0;
103 }
104
105
106 /*
107  * NULL sum_struct means we have no checksums
108  */
109 void write_sum_head(int f, struct sum_struct *sum)
110 {
111         static struct sum_struct null_sum;
112
113         if (sum == NULL)
114                 sum = &null_sum;
115
116         write_int(f, sum->count);
117         write_int(f, sum->blength);
118         if (protocol_version >= 27)
119                 write_int(f, sum->s2length);
120         write_int(f, sum->remainder);
121 }
122
123 /*
124  * set (initialize) the size entries in the per-file sum_struct
125  * calculating dynamic block and checksum sizes.
126  *
127  * This is only called from generate_and_send_sums() but is a separate
128  * function to encapsulate the logic.
129  *
130  * The block size is a rounded square root of file length.
131  *
132  * The checksum size is determined according to:
133  *     blocksum_bits = BLOCKSUM_EXP + 2*log2(file_len) - log2(block_len)
134  * provided by Donovan Baarda which gives a probability of rsync
135  * algorithm corrupting data and falling back using the whole md4
136  * checksums.
137  *
138  * This might be made one of several selectable heuristics.
139  */
140
141 static void sum_sizes_sqroot(struct sum_struct *sum, uint64 len)
142 {
143         unsigned int blength;
144         int s2length;
145         uint32 c;
146         uint64 l;
147
148         if (block_size) {
149                 blength = block_size;
150         } else if (len <= BLOCK_SIZE * BLOCK_SIZE) {
151                 blength = BLOCK_SIZE;
152         } else {
153                 l = len;
154                 c = 1;
155                 while (l >>= 2) {
156                         c <<= 1;
157                 }
158                 blength = 0;
159                 do {
160                         blength |= c;
161                         if (len < (uint64)blength * blength)
162                                 blength &= ~c;
163                         c >>= 1;
164                 } while (c >= 8);       /* round to multiple of 8 */
165                 blength = MAX(blength, BLOCK_SIZE);
166         }
167
168         if (protocol_version < 27) {
169                 s2length = csum_length;
170         } else if (csum_length == SUM_LENGTH) {
171                 s2length = SUM_LENGTH;
172         } else {
173                 int b = BLOCKSUM_BIAS;
174                 l = len;
175                 while (l >>= 1) {
176                         b += 2;
177                 }
178                 c = blength;
179                 while (c >>= 1 && b) {
180                         b--;
181                 }
182                 s2length = (b + 1 - 32 + 7) / 8; /* add a bit,
183                                                   * subtract rollsum,
184                                                   * round up
185                                                   *    --optimize in compiler--
186                                                   */
187                 s2length = MAX(s2length, csum_length);
188                 s2length = MIN(s2length, SUM_LENGTH);
189         }
190
191         sum->flength    = len;
192         sum->blength    = blength;
193         sum->s2length   = s2length;
194         sum->count      = (len + (blength - 1)) / blength;
195         sum->remainder  = (len % blength);
196
197         if (sum->count && verbose > 2) {
198                 rprintf(FINFO, "count=%.0f rem=%u blength=%u s2length=%d flength=%.0f\n",
199                         (double)sum->count, sum->remainder, sum->blength,
200                         sum->s2length, (double)sum->flength);
201         }
202 }
203
204 /**
205  * Perhaps we want to just send an empty checksum set for this file,
206  * which will force the whole thing to be literally transferred.
207  *
208  * When do we do this?  If the user's explicitly said they
209  * want the whole thing, or if { they haven't explicitly
210  * requested a delta, and it's local but not batch mode.}
211  *
212  * Whew. */
213 static BOOL disable_deltas_p(void)
214 {
215         if (whole_file > 0)
216                 return True;
217         if (whole_file == 0 || write_batch || read_batch)
218                 return False;
219         return local_server;
220 }
221
222
223 /*
224  * Generate and send a stream of signatures/checksums that describe a buffer
225  *
226  * Generate approximately one checksum every block_len bytes.
227  */
228 static void generate_and_send_sums(struct map_struct *buf, size_t len, int f_out)
229 {
230         size_t i;
231         struct sum_struct sum;
232         OFF_T offset = 0;
233
234         sum_sizes_sqroot(&sum, len);
235
236         write_sum_head(f_out, &sum);
237
238         for (i = 0; i < sum.count; i++) {
239                 unsigned int n1 = MIN(len, sum.blength);
240                 char *map = map_ptr(buf, offset, n1);
241                 uint32 sum1 = get_checksum1(map, n1);
242                 char sum2[SUM_LENGTH];
243
244                 get_checksum2(map, n1, sum2);
245
246                 if (verbose > 3) {
247                         rprintf(FINFO,
248                                 "chunk[%.0f] offset=%.0f len=%u sum1=%08lx\n",
249                                 (double)i, (double)offset, n1,
250                                 (unsigned long)sum1);
251                 }
252                 write_int(f_out, sum1);
253                 write_buf(f_out, sum2, sum.s2length);
254                 len -= n1;
255                 offset += n1;
256         }
257 }
258
259
260
261 /**
262  * Acts on file number @p i from @p flist, whose name is @p fname.
263  *
264  * First fixes up permissions, then generates checksums for the file.
265  *
266  * @note This comment was added later by mbp who was trying to work it
267  * out.  It might be wrong.
268  **/
269 void recv_generator(char *fname, struct file_struct *file, int i, int f_out)
270 {
271         int fd;
272         STRUCT_STAT st;
273         struct map_struct *mapbuf;
274         int statret;
275         char *fnamecmp;
276         char fnamecmpbuf[MAXPATHLEN];
277
278         if (list_only)
279                 return;
280
281         if (verbose > 2)
282                 rprintf(FINFO,"recv_generator(%s,%d)\n",fname,i);
283
284         if (server_exclude_list.head
285             && check_exclude(&server_exclude_list, fname,
286                              S_ISDIR(file->mode)) < 0) {
287                 if (verbose) {
288                         rprintf(FINFO, "skipping server-excluded file \"%s\"\n",
289                                 fname);
290                 }
291                 return;
292         }
293
294         statret = link_stat(fname, &st, keep_dirlinks && S_ISDIR(file->mode));
295
296         if (only_existing && statret == -1 && errno == ENOENT) {
297                 /* we only want to update existing files */
298                 if (verbose > 1)
299                         rprintf(FINFO, "not creating new file \"%s\"\n", fname);
300                 return;
301         }
302
303         if (statret == 0 &&
304             !preserve_perms &&
305             (S_ISDIR(st.st_mode) == S_ISDIR(file->mode))) {
306                 /* if the file exists already and we aren't perserving
307                  * permissions then act as though the remote end sent
308                  * us the file permissions we already have */
309                 file->mode = (file->mode & ~CHMOD_BITS)
310                            | (st.st_mode & CHMOD_BITS);
311         }
312
313         if (S_ISDIR(file->mode)) {
314                 /* The file to be received is a directory, so we need
315                  * to prepare appropriately.  If there is already a
316                  * file of that name and it is *not* a directory, then
317                  * we need to delete it.  If it doesn't exist, then
318                  * recursively create it. */
319
320                 if (dry_run)
321                         return; /* TODO: causes inaccuracies -- fix */
322                 if (statret == 0 && !S_ISDIR(st.st_mode)) {
323                         if (robust_unlink(fname) != 0) {
324                                 rsyserr(FERROR, errno,
325                                         "recv_generator: unlink %s to make room for directory",
326                                         full_fname(fname));
327                                 return;
328                         }
329                         statret = -1;
330                 }
331                 if (statret != 0 && do_mkdir(fname,file->mode) != 0 && errno != EEXIST) {
332                         if (!(relative_paths && errno == ENOENT
333                             && create_directory_path(fname, orig_umask) == 0
334                             && do_mkdir(fname, file->mode) == 0)) {
335                                 rsyserr(FERROR, errno,
336                                         "recv_generator: mkdir %s failed",
337                                         full_fname(fname));
338                         }
339                 }
340                 /* f_out is set to -1 when doing final directory-permission
341                  * and modification-time repair. */
342                 if (set_perms(fname, file, statret ? NULL : &st, 0)
343                     && verbose && f_out != -1)
344                         rprintf(FINFO,"%s/\n",fname);
345                 return;
346         }
347
348         if (preserve_links && S_ISLNK(file->mode)) {
349 #if SUPPORT_LINKS
350                 char lnk[MAXPATHLEN];
351                 int l;
352
353                 if (safe_symlinks && unsafe_symlink(file->u.link, fname)) {
354                         if (verbose) {
355                                 rprintf(FINFO, "ignoring unsafe symlink %s -> \"%s\"\n",
356                                         full_fname(fname), file->u.link);
357                         }
358                         return;
359                 }
360                 if (statret == 0) {
361                         l = readlink(fname,lnk,MAXPATHLEN-1);
362                         if (l > 0) {
363                                 lnk[l] = 0;
364                                 /* A link already pointing to the
365                                  * right place -- no further action
366                                  * required. */
367                                 if (strcmp(lnk,file->u.link) == 0) {
368                                         set_perms(fname, file, &st,
369                                                   PERMS_REPORT);
370                                         return;
371                                 }
372                         }
373                         /* Not a symlink, so delete whatever's
374                          * already there and put a new symlink
375                          * in place. */
376                         delete_file(fname);
377                 }
378                 if (do_symlink(file->u.link,fname) != 0) {
379                         rsyserr(FERROR, errno, "symlink %s -> \"%s\" failed",
380                                 full_fname(fname), file->u.link);
381                 } else {
382                         set_perms(fname,file,NULL,0);
383                         if (verbose) {
384                                 rprintf(FINFO,"%s -> %s\n", fname,file->u.link);
385                         }
386                 }
387 #endif
388                 return;
389         }
390
391 #ifdef HAVE_MKNOD
392         if (am_root && preserve_devices && IS_DEVICE(file->mode)) {
393                 if (statret != 0 ||
394                     st.st_mode != file->mode ||
395                     st.st_rdev != file->u.rdev) {
396                         delete_file(fname);
397                         if (verbose > 2) {
398                                 rprintf(FINFO,"mknod(%s,0%o,0x%x)\n",
399                                         fname,(int)file->mode,(int)file->u.rdev);
400                         }
401                         if (do_mknod(fname,file->mode,file->u.rdev) != 0) {
402                                 rsyserr(FERROR, errno, "mknod %s failed",
403                                         full_fname(fname));
404                         } else {
405                                 set_perms(fname,file,NULL,0);
406                                 if (verbose)
407                                         rprintf(FINFO,"%s\n",fname);
408                         }
409                 } else {
410                         set_perms(fname, file, &st, PERMS_REPORT);
411                 }
412                 return;
413         }
414 #endif
415
416         if (preserve_hard_links && hard_link_check(file, HL_CHECK_MASTER))
417                 return;
418
419         if (!S_ISREG(file->mode)) {
420                 rprintf(FINFO, "skipping non-regular file \"%s\"\n",fname);
421                 return;
422         }
423
424         fnamecmp = fname;
425
426         if (statret == -1 && compare_dest != NULL) {
427                 /* try the file at compare_dest instead */
428                 int saveerrno = errno;
429                 pathjoin(fnamecmpbuf, sizeof fnamecmpbuf, compare_dest, fname);
430                 statret = link_stat(fnamecmpbuf, &st, 0);
431                 if (!S_ISREG(st.st_mode))
432                         statret = -1;
433                 if (statret == -1)
434                         errno = saveerrno;
435 #if HAVE_LINK
436                 else if (link_dest && !dry_run) {
437                         if (do_link(fnamecmpbuf, fname) != 0) {
438                                 if (verbose > 0) {
439                                         rsyserr(FINFO, errno, "link %s => %s",
440                                                 fnamecmpbuf, fname);
441                                 }
442                         }
443                         fnamecmp = fnamecmpbuf;
444                 }
445 #endif
446                 else
447                         fnamecmp = fnamecmpbuf;
448         }
449
450         if (statret == -1) {
451                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
452                         return;
453                 if (errno == ENOENT) {
454                         write_int(f_out,i);
455                         if (!dry_run)
456                                 write_sum_head(f_out, NULL);
457                 } else if (verbose > 1) {
458                         rsyserr(FERROR, errno,
459                                 "recv_generator: failed to open %s",
460                                 full_fname(fname));
461                 }
462                 return;
463         }
464
465         if (!S_ISREG(st.st_mode)) {
466                 if (delete_file(fname) != 0) {
467                         return;
468                 }
469
470                 /* now pretend the file didn't exist */
471                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
472                         return;
473                 write_int(f_out,i);
474                 if (!dry_run)
475                         write_sum_head(f_out, NULL);
476                 return;
477         }
478
479         if (opt_ignore_existing && fnamecmp == fname) {
480                 if (verbose > 1)
481                         rprintf(FINFO,"%s exists\n",fname);
482                 return;
483         }
484
485         if (update_only && fnamecmp == fname
486             && cmp_modtime(st.st_mtime, file->modtime) > 0) {
487                 if (verbose > 1)
488                         rprintf(FINFO,"%s is newer\n",fname);
489                 return;
490         }
491
492         if (skip_file(fname, file, &st)) {
493                 if (fnamecmp == fname)
494                         set_perms(fname, file, &st, PERMS_REPORT);
495                 return;
496         }
497
498         if (dry_run) {
499                 write_int(f_out,i);
500                 return;
501         }
502
503         if (disable_deltas_p()) {
504                 write_int(f_out,i);
505                 write_sum_head(f_out, NULL);
506                 return;
507         }
508
509         /* open the file */
510         fd = do_open(fnamecmp, O_RDONLY, 0);
511
512         if (fd == -1) {
513                 rsyserr(FERROR, errno, "failed to open %s, continuing",
514                         full_fname(fnamecmp));
515                 /* pretend the file didn't exist */
516                 if (preserve_hard_links && hard_link_check(file, HL_SKIP))
517                         return;
518                 write_int(f_out,i);
519                 write_sum_head(f_out, NULL);
520                 return;
521         }
522
523         if (st.st_size > 0)
524                 mapbuf = map_file(fd,st.st_size);
525         else
526                 mapbuf = NULL;
527
528         if (verbose > 3) {
529                 rprintf(FINFO,"gen mapped %s of size %.0f\n", fnamecmp,
530                         (double)st.st_size);
531         }
532
533         if (verbose > 2)
534                 rprintf(FINFO, "generating and sending sums for %d\n", i);
535
536         write_int(f_out,i);
537         generate_and_send_sums(mapbuf, st.st_size, f_out);
538
539         close(fd);
540         if (mapbuf)
541                 unmap_file(mapbuf);
542 }
543
544
545 void generate_files(int f, struct file_list *flist, char *local_name)
546 {
547         int i;
548         int phase=0;
549         char fbuf[MAXPATHLEN];
550
551         if (verbose > 2) {
552                 rprintf(FINFO, "generator starting pid=%ld count=%d\n",
553                         (long)getpid(), flist->count);
554         }
555
556         if (verbose >= 2) {
557                 rprintf(FINFO,
558                         disable_deltas_p()
559                         ? "delta-transmission disabled for local transfer or --whole-file\n"
560                         : "delta transmission enabled\n");
561         }
562
563         /* we expect to just sit around now, so don't exit on a
564            timeout. If we really get a timeout then the other process should
565            exit */
566         io_timeout = 0;
567
568         for (i = 0; i < flist->count; i++) {
569                 struct file_struct *file = flist->files[i];
570                 struct file_struct copy;
571
572                 if (!file->basename)
573                         continue;
574                 /* we need to ensure that any directories we create have writeable
575                    permissions initially so that we can create the files within
576                    them. This is then fixed after the files are transferred */
577                 if (!am_root && S_ISDIR(file->mode) && !(file->mode & S_IWUSR)) {
578                         copy = *file;
579                         /* XXX: Could this be causing a problem on SCO?  Perhaps their
580                          * handling of permissions is strange? */
581                         copy.mode |= S_IWUSR; /* user write */
582                         file = &copy;
583                 }
584
585                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
586                                file, i, f);
587         }
588
589         phase++;
590         csum_length = SUM_LENGTH;
591         ignore_times=1;
592
593         if (verbose > 2)
594                 rprintf(FINFO,"generate_files phase=%d\n",phase);
595
596         write_int(f,-1);
597
598         /* files can cycle through the system more than once
599          * to catch initial checksum errors */
600         while ((i = get_redo_num()) != -1) {
601                 struct file_struct *file = flist->files[i];
602                 recv_generator(local_name ? local_name : f_name_to(file, fbuf),
603                                file, i, f);
604         }
605
606         phase++;
607         if (verbose > 2)
608                 rprintf(FINFO,"generate_files phase=%d\n",phase);
609
610         write_int(f,-1);
611
612         if (preserve_hard_links)
613                 do_hard_links();
614
615         /* now we need to fix any directory permissions that were
616          * modified during the transfer */
617         for (i = 0; i < flist->count; i++) {
618                 struct file_struct *file = flist->files[i];
619                 if (!file->basename || !S_ISDIR(file->mode))
620                         continue;
621                 recv_generator(local_name ? local_name : f_name(file),
622                                file, i, -1);
623         }
624
625         if (verbose > 2)
626                 rprintf(FINFO,"generate_files finished\n");
627 }