PostgreSQL Source Code  git master
walmethods.c
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1 /*-------------------------------------------------------------------------
2  *
3  * walmethods.c - implementations of different ways to write received wal
4  *
5  * NOTE! The caller must ensure that only one method is instantiated in
6  * any given program, and that it's only instantiated once!
7  *
8  * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
9  *
10  * IDENTIFICATION
11  * src/bin/pg_basebackup/walmethods.c
12  *-------------------------------------------------------------------------
13  */
14 
15 #include "postgres_fe.h"
16 
17 #include <sys/stat.h>
18 #include <time.h>
19 #include <unistd.h>
20 #ifdef HAVE_LIBZ
21 #include <zlib.h>
22 #endif
23 
24 #include "pgtar.h"
25 #include "common/file_perm.h"
26 #include "common/file_utils.h"
27 
28 #include "receivelog.h"
29 #include "streamutil.h"
30 
31 /* Size of zlib buffer for .tar.gz */
32 #define ZLIB_OUT_SIZE 4096
33 
34 /*-------------------------------------------------------------------------
35  * WalDirectoryMethod - write wal to a directory looking like pg_wal
36  *-------------------------------------------------------------------------
37  */
38 
39 /*
40  * Global static data for this method
41  */
42 typedef struct DirectoryMethodData
43 {
44  char *basedir;
46  bool sync;
49 
50 /*
51  * Local file handle
52  */
53 typedef struct DirectoryMethodFile
54 {
55  int fd;
56  off_t currpos;
57  char *pathname;
58  char *fullpath;
59  char *temp_suffix;
60 #ifdef HAVE_LIBZ
61  gzFile gzfp;
62 #endif
64 
65 static const char *
67 {
68  /* Directory method always sets errno, so just use strerror */
69  return strerror(errno);
70 }
71 
72 static Walfile
73 dir_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_size)
74 {
75  static char tmppath[MAXPGPATH];
76  int fd;
78 #ifdef HAVE_LIBZ
79  gzFile gzfp = NULL;
80 #endif
81 
82  snprintf(tmppath, sizeof(tmppath), "%s/%s%s%s",
83  dir_data->basedir, pathname,
84  dir_data->compression > 0 ? ".gz" : "",
85  temp_suffix ? temp_suffix : "");
86 
87  /*
88  * Open a file for non-compressed as well as compressed files. Tracking
89  * the file descriptor is important for dir_sync() method as gzflush()
90  * does not do any system calls to fsync() to make changes permanent on
91  * disk.
92  */
93  fd = open(tmppath, O_WRONLY | O_CREAT | PG_BINARY, pg_file_create_mode);
94  if (fd < 0)
95  return NULL;
96 
97 #ifdef HAVE_LIBZ
98  if (dir_data->compression > 0)
99  {
100  gzfp = gzdopen(fd, "wb");
101  if (gzfp == NULL)
102  {
103  close(fd);
104  return NULL;
105  }
106 
107  if (gzsetparams(gzfp, dir_data->compression,
108  Z_DEFAULT_STRATEGY) != Z_OK)
109  {
110  gzclose(gzfp);
111  return NULL;
112  }
113  }
114 #endif
115 
116  /* Do pre-padding on non-compressed files */
117  if (pad_to_size && dir_data->compression == 0)
118  {
119  PGAlignedXLogBlock zerobuf;
120  int bytes;
121 
122  memset(zerobuf.data, 0, XLOG_BLCKSZ);
123  for (bytes = 0; bytes < pad_to_size; bytes += XLOG_BLCKSZ)
124  {
125  errno = 0;
126  if (write(fd, zerobuf.data, XLOG_BLCKSZ) != XLOG_BLCKSZ)
127  {
128  int save_errno = errno;
129 
130  close(fd);
131 
132  /*
133  * If write didn't set errno, assume problem is no disk space.
134  */
135  errno = save_errno ? save_errno : ENOSPC;
136  return NULL;
137  }
138  }
139 
140  if (lseek(fd, 0, SEEK_SET) != 0)
141  {
142  int save_errno = errno;
143 
144  close(fd);
145  errno = save_errno;
146  return NULL;
147  }
148  }
149 
150  /*
151  * fsync WAL file and containing directory, to ensure the file is
152  * persistently created and zeroed (if padded). That's particularly
153  * important when using synchronous mode, where the file is modified and
154  * fsynced in-place, without a directory fsync.
155  */
156  if (dir_data->sync)
157  {
158  if (fsync_fname(tmppath, false) != 0 ||
159  fsync_parent_path(tmppath) != 0)
160  {
161 #ifdef HAVE_LIBZ
162  if (dir_data->compression > 0)
163  gzclose(gzfp);
164  else
165 #endif
166  close(fd);
167  return NULL;
168  }
169  }
170 
171  f = pg_malloc0(sizeof(DirectoryMethodFile));
172 #ifdef HAVE_LIBZ
173  if (dir_data->compression > 0)
174  f->gzfp = gzfp;
175 #endif
176  f->fd = fd;
177  f->currpos = 0;
178  f->pathname = pg_strdup(pathname);
179  f->fullpath = pg_strdup(tmppath);
180  if (temp_suffix)
181  f->temp_suffix = pg_strdup(temp_suffix);
182 
183  return f;
184 }
185 
186 static ssize_t
187 dir_write(Walfile f, const void *buf, size_t count)
188 {
189  ssize_t r;
191 
192  Assert(f != NULL);
193 
194 #ifdef HAVE_LIBZ
195  if (dir_data->compression > 0)
196  r = (ssize_t) gzwrite(df->gzfp, buf, count);
197  else
198 #endif
199  r = write(df->fd, buf, count);
200  if (r > 0)
201  df->currpos += r;
202  return r;
203 }
204 
205 static off_t
207 {
208  Assert(f != NULL);
209 
210  /* Use a cached value to prevent lots of reseeks */
211  return ((DirectoryMethodFile *) f)->currpos;
212 }
213 
214 static int
216 {
217  int r;
219  static char tmppath[MAXPGPATH];
220  static char tmppath2[MAXPGPATH];
221 
222  Assert(f != NULL);
223 
224 #ifdef HAVE_LIBZ
225  if (dir_data->compression > 0)
226  r = gzclose(df->gzfp);
227  else
228 #endif
229  r = close(df->fd);
230 
231  if (r == 0)
232  {
233  /* Build path to the current version of the file */
234  if (method == CLOSE_NORMAL && df->temp_suffix)
235  {
236  /*
237  * If we have a temp prefix, normal operation is to rename the
238  * file.
239  */
240  snprintf(tmppath, sizeof(tmppath), "%s/%s%s%s",
241  dir_data->basedir, df->pathname,
242  dir_data->compression > 0 ? ".gz" : "",
243  df->temp_suffix);
244  snprintf(tmppath2, sizeof(tmppath2), "%s/%s%s",
245  dir_data->basedir, df->pathname,
246  dir_data->compression > 0 ? ".gz" : "");
247  r = durable_rename(tmppath, tmppath2);
248  }
249  else if (method == CLOSE_UNLINK)
250  {
251  /* Unlink the file once it's closed */
252  snprintf(tmppath, sizeof(tmppath), "%s/%s%s%s",
253  dir_data->basedir, df->pathname,
254  dir_data->compression > 0 ? ".gz" : "",
255  df->temp_suffix ? df->temp_suffix : "");
256  r = unlink(tmppath);
257  }
258  else
259  {
260  /*
261  * Else either CLOSE_NORMAL and no temp suffix, or
262  * CLOSE_NO_RENAME. In this case, fsync the file and containing
263  * directory if sync mode is requested.
264  */
265  if (dir_data->sync)
266  {
267  r = fsync_fname(df->fullpath, false);
268  if (r == 0)
269  r = fsync_parent_path(df->fullpath);
270  }
271  }
272  }
273 
274  pg_free(df->pathname);
275  pg_free(df->fullpath);
276  if (df->temp_suffix)
277  pg_free(df->temp_suffix);
278  pg_free(df);
279 
280  return r;
281 }
282 
283 static int
285 {
286  Assert(f != NULL);
287 
288  if (!dir_data->sync)
289  return 0;
290 
291 #ifdef HAVE_LIBZ
292  if (dir_data->compression > 0)
293  {
294  if (gzflush(((DirectoryMethodFile *) f)->gzfp, Z_SYNC_FLUSH) != Z_OK)
295  return -1;
296  }
297 #endif
298 
299  return fsync(((DirectoryMethodFile *) f)->fd);
300 }
301 
302 static ssize_t
303 dir_get_file_size(const char *pathname)
304 {
305  struct stat statbuf;
306  static char tmppath[MAXPGPATH];
307 
308  snprintf(tmppath, sizeof(tmppath), "%s/%s",
309  dir_data->basedir, pathname);
310 
311  if (stat(tmppath, &statbuf) != 0)
312  return -1;
313 
314  return statbuf.st_size;
315 }
316 
317 static bool
318 dir_existsfile(const char *pathname)
319 {
320  static char tmppath[MAXPGPATH];
321  int fd;
322 
323  snprintf(tmppath, sizeof(tmppath), "%s/%s",
324  dir_data->basedir, pathname);
325 
326  fd = open(tmppath, O_RDONLY | PG_BINARY, 0);
327  if (fd < 0)
328  return false;
329  close(fd);
330  return true;
331 }
332 
333 static bool
335 {
336  if (dir_data->sync)
337  {
338  /*
339  * Files are fsynced when they are closed, but we need to fsync the
340  * directory entry here as well.
341  */
342  if (fsync_fname(dir_data->basedir, true) != 0)
343  return false;
344  }
345  return true;
346 }
347 
348 
351 {
352  WalWriteMethod *method;
353 
354  method = pg_malloc0(sizeof(WalWriteMethod));
356  method->write = dir_write;
359  method->close = dir_close;
360  method->sync = dir_sync;
361  method->existsfile = dir_existsfile;
362  method->finish = dir_finish;
363  method->getlasterror = dir_getlasterror;
364 
365  dir_data = pg_malloc0(sizeof(DirectoryMethodData));
366  dir_data->compression = compression;
367  dir_data->basedir = pg_strdup(basedir);
368  dir_data->sync = sync;
369 
370  return method;
371 }
372 
373 void
375 {
376  pg_free(dir_data->basedir);
377  pg_free(dir_data);
378 }
379 
380 
381 /*-------------------------------------------------------------------------
382  * WalTarMethod - write wal to a tar file containing pg_wal contents
383  *-------------------------------------------------------------------------
384  */
385 
386 typedef struct TarMethodFile
387 {
388  off_t ofs_start; /* Where does the *header* for this file start */
389  off_t currpos;
390  char header[512];
391  char *pathname;
392  size_t pad_to_size;
393 } TarMethodFile;
394 
395 typedef struct TarMethodData
396 {
397  char *tarfilename;
398  int fd;
400  bool sync;
402  char lasterror[1024];
403 #ifdef HAVE_LIBZ
404  z_streamp zp;
405  void *zlibOut;
406 #endif
407 } TarMethodData;
408 static TarMethodData *tar_data = NULL;
409 
410 #define tar_clear_error() tar_data->lasterror[0] = '\0'
411 #define tar_set_error(msg) strlcpy(tar_data->lasterror, _(msg), sizeof(tar_data->lasterror))
412 
413 static const char *
415 {
416  /*
417  * If a custom error is set, return that one. Otherwise, assume errno is
418  * set and return that one.
419  */
420  if (tar_data->lasterror[0])
421  return tar_data->lasterror;
422  return strerror(errno);
423 }
424 
425 #ifdef HAVE_LIBZ
426 static bool
427 tar_write_compressed_data(void *buf, size_t count, bool flush)
428 {
429  tar_data->zp->next_in = buf;
430  tar_data->zp->avail_in = count;
431 
432  while (tar_data->zp->avail_in || flush)
433  {
434  int r;
435 
436  r = deflate(tar_data->zp, flush ? Z_FINISH : Z_NO_FLUSH);
437  if (r == Z_STREAM_ERROR)
438  {
439  tar_set_error("could not compress data");
440  return false;
441  }
442 
443  if (tar_data->zp->avail_out < ZLIB_OUT_SIZE)
444  {
445  size_t len = ZLIB_OUT_SIZE - tar_data->zp->avail_out;
446 
447  errno = 0;
448  if (write(tar_data->fd, tar_data->zlibOut, len) != len)
449  {
450  /*
451  * If write didn't set errno, assume problem is no disk space.
452  */
453  if (errno == 0)
454  errno = ENOSPC;
455  return false;
456  }
457 
458  tar_data->zp->next_out = tar_data->zlibOut;
459  tar_data->zp->avail_out = ZLIB_OUT_SIZE;
460  }
461 
462  if (r == Z_STREAM_END)
463  break;
464  }
465 
466  if (flush)
467  {
468  /* Reset the stream for writing */
469  if (deflateReset(tar_data->zp) != Z_OK)
470  {
471  tar_set_error("could not reset compression stream");
472  return false;
473  }
474  }
475 
476  return true;
477 }
478 #endif
479 
480 static ssize_t
481 tar_write(Walfile f, const void *buf, size_t count)
482 {
483  ssize_t r;
484 
485  Assert(f != NULL);
486  tar_clear_error();
487 
488  /* Tarfile will always be positioned at the end */
489  if (!tar_data->compression)
490  {
491  r = write(tar_data->fd, buf, count);
492  if (r > 0)
493  ((TarMethodFile *) f)->currpos += r;
494  return r;
495  }
496 #ifdef HAVE_LIBZ
497  else
498  {
499  if (!tar_write_compressed_data(unconstify(void *, buf), count, false))
500  return -1;
501  ((TarMethodFile *) f)->currpos += count;
502  return count;
503  }
504 #else
505  else
506  /* Can't happen - compression enabled with no libz */
507  return -1;
508 #endif
509 }
510 
511 static bool
513 {
514  PGAlignedXLogBlock zerobuf;
515  size_t bytesleft = bytes;
516 
517  memset(zerobuf.data, 0, XLOG_BLCKSZ);
518  while (bytesleft)
519  {
520  size_t bytestowrite = Min(bytesleft, XLOG_BLCKSZ);
521  ssize_t r = tar_write(f, zerobuf.data, bytestowrite);
522 
523  if (r < 0)
524  return false;
525  bytesleft -= r;
526  }
527 
528  return true;
529 }
530 
531 static Walfile
532 tar_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_size)
533 {
534  int save_errno;
535  static char tmppath[MAXPGPATH];
536 
537  tar_clear_error();
538 
539  if (tar_data->fd < 0)
540  {
541  /*
542  * We open the tar file only when we first try to write to it.
543  */
544  tar_data->fd = open(tar_data->tarfilename,
545  O_WRONLY | O_CREAT | PG_BINARY,
547  if (tar_data->fd < 0)
548  return NULL;
549 
550 #ifdef HAVE_LIBZ
551  if (tar_data->compression)
552  {
553  tar_data->zp = (z_streamp) pg_malloc(sizeof(z_stream));
554  tar_data->zp->zalloc = Z_NULL;
555  tar_data->zp->zfree = Z_NULL;
556  tar_data->zp->opaque = Z_NULL;
557  tar_data->zp->next_out = tar_data->zlibOut;
558  tar_data->zp->avail_out = ZLIB_OUT_SIZE;
559 
560  /*
561  * Initialize deflation library. Adding the magic value 16 to the
562  * default 15 for the windowBits parameter makes the output be
563  * gzip instead of zlib.
564  */
565  if (deflateInit2(tar_data->zp, tar_data->compression, Z_DEFLATED, 15 + 16, 8, Z_DEFAULT_STRATEGY) != Z_OK)
566  {
567  pg_free(tar_data->zp);
568  tar_data->zp = NULL;
569  tar_set_error("could not initialize compression library");
570  return NULL;
571  }
572  }
573 #endif
574 
575  /* There's no tar header itself, the file starts with regular files */
576  }
577 
578  Assert(tar_data->currentfile == NULL);
579  if (tar_data->currentfile != NULL)
580  {
581  tar_set_error("implementation error: tar files can't have more than one open file");
582  return NULL;
583  }
584 
585  tar_data->currentfile = pg_malloc0(sizeof(TarMethodFile));
586 
587  snprintf(tmppath, sizeof(tmppath), "%s%s",
588  pathname, temp_suffix ? temp_suffix : "");
589 
590  /* Create a header with size set to 0 - we will fill out the size on close */
591  if (tarCreateHeader(tar_data->currentfile->header, tmppath, NULL, 0, S_IRUSR | S_IWUSR, 0, 0, time(NULL)) != TAR_OK)
592  {
593  pg_free(tar_data->currentfile);
594  tar_data->currentfile = NULL;
595  tar_set_error("could not create tar header");
596  return NULL;
597  }
598 
599 #ifdef HAVE_LIBZ
600  if (tar_data->compression)
601  {
602  /* Flush existing data */
603  if (!tar_write_compressed_data(NULL, 0, true))
604  return NULL;
605 
606  /* Turn off compression for header */
607  if (deflateParams(tar_data->zp, 0, 0) != Z_OK)
608  {
609  tar_set_error("could not change compression parameters");
610  return NULL;
611  }
612  }
613 #endif
614 
615  tar_data->currentfile->ofs_start = lseek(tar_data->fd, 0, SEEK_CUR);
616  if (tar_data->currentfile->ofs_start == -1)
617  {
618  save_errno = errno;
619  pg_free(tar_data->currentfile);
620  tar_data->currentfile = NULL;
621  errno = save_errno;
622  return NULL;
623  }
624  tar_data->currentfile->currpos = 0;
625 
626  if (!tar_data->compression)
627  {
628  errno = 0;
629  if (write(tar_data->fd, tar_data->currentfile->header, 512) != 512)
630  {
631  save_errno = errno;
632  pg_free(tar_data->currentfile);
633  tar_data->currentfile = NULL;
634  /* if write didn't set errno, assume problem is no disk space */
635  errno = save_errno ? save_errno : ENOSPC;
636  return NULL;
637  }
638  }
639 #ifdef HAVE_LIBZ
640  else
641  {
642  /* Write header through the zlib APIs but with no compression */
643  if (!tar_write_compressed_data(tar_data->currentfile->header, 512, true))
644  return NULL;
645 
646  /* Re-enable compression for the rest of the file */
647  if (deflateParams(tar_data->zp, tar_data->compression, 0) != Z_OK)
648  {
649  tar_set_error("could not change compression parameters");
650  return NULL;
651  }
652  }
653 #endif
654 
655  tar_data->currentfile->pathname = pg_strdup(pathname);
656 
657  /*
658  * Uncompressed files are padded on creation, but for compression we can't
659  * do that
660  */
661  if (pad_to_size)
662  {
663  tar_data->currentfile->pad_to_size = pad_to_size;
664  if (!tar_data->compression)
665  {
666  /* Uncompressed, so pad now */
667  tar_write_padding_data(tar_data->currentfile, pad_to_size);
668  /* Seek back to start */
669  if (lseek(tar_data->fd, tar_data->currentfile->ofs_start + 512, SEEK_SET) != tar_data->currentfile->ofs_start + 512)
670  return NULL;
671 
672  tar_data->currentfile->currpos = 0;
673  }
674  }
675 
676  return tar_data->currentfile;
677 }
678 
679 static ssize_t
680 tar_get_file_size(const char *pathname)
681 {
682  tar_clear_error();
683 
684  /* Currently not used, so not supported */
685  errno = ENOSYS;
686  return -1;
687 }
688 
689 static off_t
691 {
692  Assert(f != NULL);
693  tar_clear_error();
694 
695  return ((TarMethodFile *) f)->currpos;
696 }
697 
698 static int
700 {
701  Assert(f != NULL);
702  tar_clear_error();
703 
704  if (!tar_data->sync)
705  return 0;
706 
707  /*
708  * Always sync the whole tarfile, because that's all we can do. This makes
709  * no sense on compressed files, so just ignore those.
710  */
711  if (tar_data->compression)
712  return 0;
713 
714  return fsync(tar_data->fd);
715 }
716 
717 static int
719 {
720  ssize_t filesize;
721  int padding;
722  TarMethodFile *tf = (TarMethodFile *) f;
723 
724  Assert(f != NULL);
725  tar_clear_error();
726 
727  if (method == CLOSE_UNLINK)
728  {
729  if (tar_data->compression)
730  {
731  tar_set_error("unlink not supported with compression");
732  return -1;
733  }
734 
735  /*
736  * Unlink the file that we just wrote to the tar. We do this by
737  * truncating it to the start of the header. This is safe as we only
738  * allow writing of the very last file.
739  */
740  if (ftruncate(tar_data->fd, tf->ofs_start) != 0)
741  return -1;
742 
743  pg_free(tf->pathname);
744  pg_free(tf);
745  tar_data->currentfile = NULL;
746 
747  return 0;
748  }
749 
750  /*
751  * Pad the file itself with zeroes if necessary. Note that this is
752  * different from the tar format padding -- this is the padding we asked
753  * for when the file was opened.
754  */
755  if (tf->pad_to_size)
756  {
757  if (tar_data->compression)
758  {
759  /*
760  * A compressed tarfile is padded on close since we cannot know
761  * the size of the compressed output until the end.
762  */
763  size_t sizeleft = tf->pad_to_size - tf->currpos;
764 
765  if (sizeleft)
766  {
767  if (!tar_write_padding_data(tf, sizeleft))
768  return -1;
769  }
770  }
771  else
772  {
773  /*
774  * An uncompressed tarfile was padded on creation, so just adjust
775  * the current position as if we seeked to the end.
776  */
777  tf->currpos = tf->pad_to_size;
778  }
779  }
780 
781  /*
782  * Get the size of the file, and pad the current data up to the nearest
783  * 512 byte boundary.
784  */
785  filesize = tar_get_current_pos(f);
786  padding = ((filesize + 511) & ~511) - filesize;
787  if (padding)
788  {
789  char zerobuf[512];
790 
791  MemSet(zerobuf, 0, padding);
792  if (tar_write(f, zerobuf, padding) != padding)
793  return -1;
794  }
795 
796 
797 #ifdef HAVE_LIBZ
798  if (tar_data->compression)
799  {
800  /* Flush the current buffer */
801  if (!tar_write_compressed_data(NULL, 0, true))
802  {
803  errno = EINVAL;
804  return -1;
805  }
806  }
807 #endif
808 
809  /*
810  * Now go back and update the header with the correct filesize and
811  * possibly also renaming the file. We overwrite the entire current header
812  * when done, including the checksum.
813  */
814  print_tar_number(&(tf->header[124]), 12, filesize);
815 
816  if (method == CLOSE_NORMAL)
817 
818  /*
819  * We overwrite it with what it was before if we have no tempname,
820  * since we're going to write the buffer anyway.
821  */
822  strlcpy(&(tf->header[0]), tf->pathname, 100);
823 
824  print_tar_number(&(tf->header[148]), 8, tarChecksum(((TarMethodFile *) f)->header));
825  if (lseek(tar_data->fd, tf->ofs_start, SEEK_SET) != ((TarMethodFile *) f)->ofs_start)
826  return -1;
827  if (!tar_data->compression)
828  {
829  errno = 0;
830  if (write(tar_data->fd, tf->header, 512) != 512)
831  {
832  /* if write didn't set errno, assume problem is no disk space */
833  if (errno == 0)
834  errno = ENOSPC;
835  return -1;
836  }
837  }
838 #ifdef HAVE_LIBZ
839  else
840  {
841  /* Turn off compression */
842  if (deflateParams(tar_data->zp, 0, 0) != Z_OK)
843  {
844  tar_set_error("could not change compression parameters");
845  return -1;
846  }
847 
848  /* Overwrite the header, assuming the size will be the same */
849  if (!tar_write_compressed_data(tar_data->currentfile->header, 512, true))
850  return -1;
851 
852  /* Turn compression back on */
853  if (deflateParams(tar_data->zp, tar_data->compression, 0) != Z_OK)
854  {
855  tar_set_error("could not change compression parameters");
856  return -1;
857  }
858  }
859 #endif
860 
861  /* Move file pointer back down to end, so we can write the next file */
862  if (lseek(tar_data->fd, 0, SEEK_END) < 0)
863  return -1;
864 
865  /* Always fsync on close, so the padding gets fsynced */
866  if (tar_sync(f) < 0)
867  exit(1);
868 
869  /* Clean up and done */
870  pg_free(tf->pathname);
871  pg_free(tf);
872  tar_data->currentfile = NULL;
873 
874  return 0;
875 }
876 
877 static bool
878 tar_existsfile(const char *pathname)
879 {
880  tar_clear_error();
881  /* We only deal with new tarfiles, so nothing externally created exists */
882  return false;
883 }
884 
885 static bool
887 {
888  char zerobuf[1024];
889 
890  tar_clear_error();
891 
892  if (tar_data->currentfile)
893  {
894  if (tar_close(tar_data->currentfile, CLOSE_NORMAL) != 0)
895  return false;
896  }
897 
898  /* A tarfile always ends with two empty blocks */
899  MemSet(zerobuf, 0, sizeof(zerobuf));
900  if (!tar_data->compression)
901  {
902  errno = 0;
903  if (write(tar_data->fd, zerobuf, sizeof(zerobuf)) != sizeof(zerobuf))
904  {
905  /* if write didn't set errno, assume problem is no disk space */
906  if (errno == 0)
907  errno = ENOSPC;
908  return false;
909  }
910  }
911 #ifdef HAVE_LIBZ
912  else
913  {
914  if (!tar_write_compressed_data(zerobuf, sizeof(zerobuf), false))
915  return false;
916 
917  /* Also flush all data to make sure the gzip stream is finished */
918  tar_data->zp->next_in = NULL;
919  tar_data->zp->avail_in = 0;
920  while (true)
921  {
922  int r;
923 
924  r = deflate(tar_data->zp, Z_FINISH);
925 
926  if (r == Z_STREAM_ERROR)
927  {
928  tar_set_error("could not compress data");
929  return false;
930  }
931  if (tar_data->zp->avail_out < ZLIB_OUT_SIZE)
932  {
933  size_t len = ZLIB_OUT_SIZE - tar_data->zp->avail_out;
934 
935  errno = 0;
936  if (write(tar_data->fd, tar_data->zlibOut, len) != len)
937  {
938  /*
939  * If write didn't set errno, assume problem is no disk
940  * space.
941  */
942  if (errno == 0)
943  errno = ENOSPC;
944  return false;
945  }
946  }
947  if (r == Z_STREAM_END)
948  break;
949  }
950 
951  if (deflateEnd(tar_data->zp) != Z_OK)
952  {
953  tar_set_error("could not close compression stream");
954  return false;
955  }
956  }
957 #endif
958 
959  /* sync the empty blocks as well, since they're after the last file */
960  if (tar_data->sync)
961  {
962  if (fsync(tar_data->fd) != 0)
963  return false;
964  }
965 
966  if (close(tar_data->fd) != 0)
967  return false;
968 
969  tar_data->fd = -1;
970 
971  if (tar_data->sync)
972  {
973  if (fsync_fname(tar_data->tarfilename, false) != 0)
974  return false;
975  if (fsync_parent_path(tar_data->tarfilename) != 0)
976  return false;
977  }
978 
979  return true;
980 }
981 
983 CreateWalTarMethod(const char *tarbase, int compression, bool sync)
984 {
985  WalWriteMethod *method;
986  const char *suffix = (compression != 0) ? ".tar.gz" : ".tar";
987 
988  method = pg_malloc0(sizeof(WalWriteMethod));
990  method->write = tar_write;
993  method->close = tar_close;
994  method->sync = tar_sync;
995  method->existsfile = tar_existsfile;
996  method->finish = tar_finish;
997  method->getlasterror = tar_getlasterror;
998 
999  tar_data = pg_malloc0(sizeof(TarMethodData));
1000  tar_data->tarfilename = pg_malloc0(strlen(tarbase) + strlen(suffix) + 1);
1001  sprintf(tar_data->tarfilename, "%s%s", tarbase, suffix);
1002  tar_data->fd = -1;
1003  tar_data->compression = compression;
1004  tar_data->sync = sync;
1005 #ifdef HAVE_LIBZ
1006  if (compression)
1007  tar_data->zlibOut = (char *) pg_malloc(ZLIB_OUT_SIZE + 1);
1008 #endif
1009 
1010  return method;
1011 }
1012 
1013 void
1015 {
1016  pg_free(tar_data->tarfilename);
1017 #ifdef HAVE_LIBZ
1018  if (tar_data->compression)
1019  pg_free(tar_data->zlibOut);
1020 #endif
1021  pg_free(tar_data);
1022 }
WalCloseMethod
Definition: walmethods.h:15
int pg_file_create_mode
Definition: file_perm.c:19
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Definition: walmethods.c:206
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Definition: walmethods.h:13
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Definition: walmethods.h:67
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Definition: walmethods.c:350
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Definition: walmethods.c:481
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Definition: walmethods.h:78
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Definition: walmethods.c:718
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Definition: walmethods.h:62
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Definition: walmethods.c:390
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Definition: port.h:194
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Definition: walmethods.c:334
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Definition: win32_port.h:63
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Definition: win32_port.h:263
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Definition: fe_memutils.c:53
#define MAXPGPATH
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Definition: pg_test_fsync.c:68
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Definition: walmethods.c:532
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Definition: walmethods.h:59
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Definition: fe_memutils.c:85
z_stream * z_streamp
#define tar_set_error(msg)
Definition: walmethods.c:411
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Definition: walmethods.c:187
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Definition: fd.c:606
static bool tar_write_padding_data(TarMethodFile *f, size_t bytes)
Definition: walmethods.c:512
static ssize_t tar_get_file_size(const char *pathname)
Definition: walmethods.c:680
#define unconstify(underlying_type, expr)
Definition: c.h:1163
#define stat(a, b)
Definition: win32_port.h:255
enum tarError tarCreateHeader(char *h, const char *filename, const char *linktarget, pgoff_t size, mode_t mode, uid_t uid, gid_t gid, time_t mtime)
Definition: tar.c:112
void FreeWalTarMethod(void)
Definition: walmethods.c:1014
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Definition: walmethods.c:48
static bool tar_existsfile(const char *pathname)
Definition: walmethods.c:878
static int dir_close(Walfile f, WalCloseMethod method)
Definition: walmethods.c:215
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Definition: walmethods.c:690
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Definition: tar.c:88
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Definition: walmethods.c:397
TarMethodFile * currentfile
Definition: walmethods.c:401
size_t strlcpy(char *dst, const char *src, size_t siz)
Definition: strlcpy.c:45
#define Assert(condition)
Definition: c.h:732
WalWriteMethod * CreateWalTarMethod(const char *tarbase, int compression, bool sync)
Definition: walmethods.c:983
struct TarMethodFile TarMethodFile
#define strerror
Definition: port.h:205
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Definition: tar.c:20
char lasterror[1024]
Definition: walmethods.c:402
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Definition: walmethods.c:410
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Definition: fe_memutils.c:105
#define ZLIB_OUT_SIZE
Definition: walmethods.c:32
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Definition: walmethods.h:75
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Definition: pg_regress.c:210
#define S_IRUSR
Definition: win32_port.h:260
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Definition: walmethods.h:50
Walfile(* open_for_write)(const char *pathname, const char *temp_suffix, size_t pad_to_size)
Definition: walmethods.h:41
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Definition: walmethods.c:73
struct TarMethodData TarMethodData
ssize_t(* get_file_size)(const char *pathname)
Definition: walmethods.h:53
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Definition: walmethods.c:66
static ssize_t dir_get_file_size(const char *pathname)
Definition: walmethods.c:303
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Definition: win32.h:12
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Definition: c.h:1068
#define snprintf
Definition: port.h:192
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Definition: fd.c:3419
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Definition: walmethods.c:388
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Definition: walmethods.c:408
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Definition: walmethods.c:374
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Definition: walmethods.c:318
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Definition: walmethods.c:699
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Definition: win32_port.h:60