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) 1996-2020, 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 "common/file_perm.h"
25 #include "common/file_utils.h"
26 #include "pgtar.h"
27 #include "receivelog.h"
28 #include "streamutil.h"
29 
30 /* Size of zlib buffer for .tar.gz */
31 #define ZLIB_OUT_SIZE 4096
32 
33 /*-------------------------------------------------------------------------
34  * WalDirectoryMethod - write wal to a directory looking like pg_wal
35  *-------------------------------------------------------------------------
36  */
37 
38 /*
39  * Global static data for this method
40  */
41 typedef struct DirectoryMethodData
42 {
43  char *basedir;
45  bool sync;
48 
49 /*
50  * Local file handle
51  */
52 typedef struct DirectoryMethodFile
53 {
54  int fd;
55  off_t currpos;
56  char *pathname;
57  char *fullpath;
58  char *temp_suffix;
59 #ifdef HAVE_LIBZ
60  gzFile gzfp;
61 #endif
63 
64 static const char *
66 {
67  /* Directory method always sets errno, so just use strerror */
68  return strerror(errno);
69 }
70 
71 static Walfile
72 dir_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_size)
73 {
74  static char tmppath[MAXPGPATH];
75  int fd;
77 #ifdef HAVE_LIBZ
78  gzFile gzfp = NULL;
79 #endif
80 
81  snprintf(tmppath, sizeof(tmppath), "%s/%s%s%s",
82  dir_data->basedir, pathname,
83  dir_data->compression > 0 ? ".gz" : "",
84  temp_suffix ? temp_suffix : "");
85 
86  /*
87  * Open a file for non-compressed as well as compressed files. Tracking
88  * the file descriptor is important for dir_sync() method as gzflush()
89  * does not do any system calls to fsync() to make changes permanent on
90  * disk.
91  */
92  fd = open(tmppath, O_WRONLY | O_CREAT | PG_BINARY, pg_file_create_mode);
93  if (fd < 0)
94  return NULL;
95 
96 #ifdef HAVE_LIBZ
97  if (dir_data->compression > 0)
98  {
99  gzfp = gzdopen(fd, "wb");
100  if (gzfp == NULL)
101  {
102  close(fd);
103  return NULL;
104  }
105 
106  if (gzsetparams(gzfp, dir_data->compression,
107  Z_DEFAULT_STRATEGY) != Z_OK)
108  {
109  gzclose(gzfp);
110  return NULL;
111  }
112  }
113 #endif
114 
115  /* Do pre-padding on non-compressed files */
116  if (pad_to_size && dir_data->compression == 0)
117  {
118  PGAlignedXLogBlock zerobuf;
119  int bytes;
120 
121  memset(zerobuf.data, 0, XLOG_BLCKSZ);
122  for (bytes = 0; bytes < pad_to_size; bytes += XLOG_BLCKSZ)
123  {
124  errno = 0;
125  if (write(fd, zerobuf.data, XLOG_BLCKSZ) != XLOG_BLCKSZ)
126  {
127  int save_errno = errno;
128 
129  close(fd);
130 
131  /*
132  * If write didn't set errno, assume problem is no disk space.
133  */
134  errno = save_errno ? save_errno : ENOSPC;
135  return NULL;
136  }
137  }
138 
139  if (lseek(fd, 0, SEEK_SET) != 0)
140  {
141  int save_errno = errno;
142 
143  close(fd);
144  errno = save_errno;
145  return NULL;
146  }
147  }
148 
149  /*
150  * fsync WAL file and containing directory, to ensure the file is
151  * persistently created and zeroed (if padded). That's particularly
152  * important when using synchronous mode, where the file is modified and
153  * fsynced in-place, without a directory fsync.
154  */
155  if (dir_data->sync)
156  {
157  if (fsync_fname(tmppath, false) != 0 ||
158  fsync_parent_path(tmppath) != 0)
159  {
160 #ifdef HAVE_LIBZ
161  if (dir_data->compression > 0)
162  gzclose(gzfp);
163  else
164 #endif
165  close(fd);
166  return NULL;
167  }
168  }
169 
170  f = pg_malloc0(sizeof(DirectoryMethodFile));
171 #ifdef HAVE_LIBZ
172  if (dir_data->compression > 0)
173  f->gzfp = gzfp;
174 #endif
175  f->fd = fd;
176  f->currpos = 0;
177  f->pathname = pg_strdup(pathname);
178  f->fullpath = pg_strdup(tmppath);
179  if (temp_suffix)
180  f->temp_suffix = pg_strdup(temp_suffix);
181 
182  return f;
183 }
184 
185 static ssize_t
186 dir_write(Walfile f, const void *buf, size_t count)
187 {
188  ssize_t r;
190 
191  Assert(f != NULL);
192 
193 #ifdef HAVE_LIBZ
194  if (dir_data->compression > 0)
195  r = (ssize_t) gzwrite(df->gzfp, buf, count);
196  else
197 #endif
198  r = write(df->fd, buf, count);
199  if (r > 0)
200  df->currpos += r;
201  return r;
202 }
203 
204 static off_t
206 {
207  Assert(f != NULL);
208 
209  /* Use a cached value to prevent lots of reseeks */
210  return ((DirectoryMethodFile *) f)->currpos;
211 }
212 
213 static int
215 {
216  int r;
218  static char tmppath[MAXPGPATH];
219  static char tmppath2[MAXPGPATH];
220 
221  Assert(f != NULL);
222 
223 #ifdef HAVE_LIBZ
224  if (dir_data->compression > 0)
225  r = gzclose(df->gzfp);
226  else
227 #endif
228  r = close(df->fd);
229 
230  if (r == 0)
231  {
232  /* Build path to the current version of the file */
233  if (method == CLOSE_NORMAL && df->temp_suffix)
234  {
235  /*
236  * If we have a temp prefix, normal operation is to rename the
237  * file.
238  */
239  snprintf(tmppath, sizeof(tmppath), "%s/%s%s%s",
240  dir_data->basedir, df->pathname,
241  dir_data->compression > 0 ? ".gz" : "",
242  df->temp_suffix);
243  snprintf(tmppath2, sizeof(tmppath2), "%s/%s%s",
244  dir_data->basedir, df->pathname,
245  dir_data->compression > 0 ? ".gz" : "");
246  r = durable_rename(tmppath, tmppath2);
247  }
248  else if (method == CLOSE_UNLINK)
249  {
250  /* Unlink the file once it's closed */
251  snprintf(tmppath, sizeof(tmppath), "%s/%s%s%s",
252  dir_data->basedir, df->pathname,
253  dir_data->compression > 0 ? ".gz" : "",
254  df->temp_suffix ? df->temp_suffix : "");
255  r = unlink(tmppath);
256  }
257  else
258  {
259  /*
260  * Else either CLOSE_NORMAL and no temp suffix, or
261  * CLOSE_NO_RENAME. In this case, fsync the file and containing
262  * directory if sync mode is requested.
263  */
264  if (dir_data->sync)
265  {
266  r = fsync_fname(df->fullpath, false);
267  if (r == 0)
268  r = fsync_parent_path(df->fullpath);
269  }
270  }
271  }
272 
273  pg_free(df->pathname);
274  pg_free(df->fullpath);
275  if (df->temp_suffix)
276  pg_free(df->temp_suffix);
277  pg_free(df);
278 
279  return r;
280 }
281 
282 static int
284 {
285  Assert(f != NULL);
286 
287  if (!dir_data->sync)
288  return 0;
289 
290 #ifdef HAVE_LIBZ
291  if (dir_data->compression > 0)
292  {
293  if (gzflush(((DirectoryMethodFile *) f)->gzfp, Z_SYNC_FLUSH) != Z_OK)
294  return -1;
295  }
296 #endif
297 
298  return fsync(((DirectoryMethodFile *) f)->fd);
299 }
300 
301 static ssize_t
302 dir_get_file_size(const char *pathname)
303 {
304  struct stat statbuf;
305  static char tmppath[MAXPGPATH];
306 
307  snprintf(tmppath, sizeof(tmppath), "%s/%s",
308  dir_data->basedir, pathname);
309 
310  if (stat(tmppath, &statbuf) != 0)
311  return -1;
312 
313  return statbuf.st_size;
314 }
315 
316 static bool
317 dir_existsfile(const char *pathname)
318 {
319  static char tmppath[MAXPGPATH];
320  int fd;
321 
322  snprintf(tmppath, sizeof(tmppath), "%s/%s",
323  dir_data->basedir, pathname);
324 
325  fd = open(tmppath, O_RDONLY | PG_BINARY, 0);
326  if (fd < 0)
327  return false;
328  close(fd);
329  return true;
330 }
331 
332 static bool
334 {
335  if (dir_data->sync)
336  {
337  /*
338  * Files are fsynced when they are closed, but we need to fsync the
339  * directory entry here as well.
340  */
341  if (fsync_fname(dir_data->basedir, true) != 0)
342  return false;
343  }
344  return true;
345 }
346 
347 
350 {
351  WalWriteMethod *method;
352 
353  method = pg_malloc0(sizeof(WalWriteMethod));
355  method->write = dir_write;
358  method->close = dir_close;
359  method->sync = dir_sync;
360  method->existsfile = dir_existsfile;
361  method->finish = dir_finish;
362  method->getlasterror = dir_getlasterror;
363 
364  dir_data = pg_malloc0(sizeof(DirectoryMethodData));
365  dir_data->compression = compression;
366  dir_data->basedir = pg_strdup(basedir);
367  dir_data->sync = sync;
368 
369  return method;
370 }
371 
372 void
374 {
375  pg_free(dir_data->basedir);
376  pg_free(dir_data);
377 }
378 
379 
380 /*-------------------------------------------------------------------------
381  * WalTarMethod - write wal to a tar file containing pg_wal contents
382  *-------------------------------------------------------------------------
383  */
384 
385 typedef struct TarMethodFile
386 {
387  off_t ofs_start; /* Where does the *header* for this file start */
388  off_t currpos;
390  char *pathname;
391  size_t pad_to_size;
392 } TarMethodFile;
393 
394 typedef struct TarMethodData
395 {
396  char *tarfilename;
397  int fd;
399  bool sync;
401  char lasterror[1024];
402 #ifdef HAVE_LIBZ
403  z_streamp zp;
404  void *zlibOut;
405 #endif
406 } TarMethodData;
407 static TarMethodData *tar_data = NULL;
408 
409 #define tar_clear_error() tar_data->lasterror[0] = '\0'
410 #define tar_set_error(msg) strlcpy(tar_data->lasterror, _(msg), sizeof(tar_data->lasterror))
411 
412 static const char *
414 {
415  /*
416  * If a custom error is set, return that one. Otherwise, assume errno is
417  * set and return that one.
418  */
419  if (tar_data->lasterror[0])
420  return tar_data->lasterror;
421  return strerror(errno);
422 }
423 
424 #ifdef HAVE_LIBZ
425 static bool
426 tar_write_compressed_data(void *buf, size_t count, bool flush)
427 {
428  tar_data->zp->next_in = buf;
429  tar_data->zp->avail_in = count;
430 
431  while (tar_data->zp->avail_in || flush)
432  {
433  int r;
434 
435  r = deflate(tar_data->zp, flush ? Z_FINISH : Z_NO_FLUSH);
436  if (r == Z_STREAM_ERROR)
437  {
438  tar_set_error("could not compress data");
439  return false;
440  }
441 
442  if (tar_data->zp->avail_out < ZLIB_OUT_SIZE)
443  {
444  size_t len = ZLIB_OUT_SIZE - tar_data->zp->avail_out;
445 
446  errno = 0;
447  if (write(tar_data->fd, tar_data->zlibOut, len) != len)
448  {
449  /*
450  * If write didn't set errno, assume problem is no disk space.
451  */
452  if (errno == 0)
453  errno = ENOSPC;
454  return false;
455  }
456 
457  tar_data->zp->next_out = tar_data->zlibOut;
458  tar_data->zp->avail_out = ZLIB_OUT_SIZE;
459  }
460 
461  if (r == Z_STREAM_END)
462  break;
463  }
464 
465  if (flush)
466  {
467  /* Reset the stream for writing */
468  if (deflateReset(tar_data->zp) != Z_OK)
469  {
470  tar_set_error("could not reset compression stream");
471  return false;
472  }
473  }
474 
475  return true;
476 }
477 #endif
478 
479 static ssize_t
480 tar_write(Walfile f, const void *buf, size_t count)
481 {
482  ssize_t r;
483 
484  Assert(f != NULL);
485  tar_clear_error();
486 
487  /* Tarfile will always be positioned at the end */
488  if (!tar_data->compression)
489  {
490  r = write(tar_data->fd, buf, count);
491  if (r > 0)
492  ((TarMethodFile *) f)->currpos += r;
493  return r;
494  }
495 #ifdef HAVE_LIBZ
496  else
497  {
498  if (!tar_write_compressed_data(unconstify(void *, buf), count, false))
499  return -1;
500  ((TarMethodFile *) f)->currpos += count;
501  return count;
502  }
503 #else
504  else
505  /* Can't happen - compression enabled with no libz */
506  return -1;
507 #endif
508 }
509 
510 static bool
512 {
513  PGAlignedXLogBlock zerobuf;
514  size_t bytesleft = bytes;
515 
516  memset(zerobuf.data, 0, XLOG_BLCKSZ);
517  while (bytesleft)
518  {
519  size_t bytestowrite = Min(bytesleft, XLOG_BLCKSZ);
520  ssize_t r = tar_write(f, zerobuf.data, bytestowrite);
521 
522  if (r < 0)
523  return false;
524  bytesleft -= r;
525  }
526 
527  return true;
528 }
529 
530 static Walfile
531 tar_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_size)
532 {
533  int save_errno;
534  static char tmppath[MAXPGPATH];
535 
536  tar_clear_error();
537 
538  if (tar_data->fd < 0)
539  {
540  /*
541  * We open the tar file only when we first try to write to it.
542  */
543  tar_data->fd = open(tar_data->tarfilename,
544  O_WRONLY | O_CREAT | PG_BINARY,
546  if (tar_data->fd < 0)
547  return NULL;
548 
549 #ifdef HAVE_LIBZ
550  if (tar_data->compression)
551  {
552  tar_data->zp = (z_streamp) pg_malloc(sizeof(z_stream));
553  tar_data->zp->zalloc = Z_NULL;
554  tar_data->zp->zfree = Z_NULL;
555  tar_data->zp->opaque = Z_NULL;
556  tar_data->zp->next_out = tar_data->zlibOut;
557  tar_data->zp->avail_out = ZLIB_OUT_SIZE;
558 
559  /*
560  * Initialize deflation library. Adding the magic value 16 to the
561  * default 15 for the windowBits parameter makes the output be
562  * gzip instead of zlib.
563  */
564  if (deflateInit2(tar_data->zp, tar_data->compression, Z_DEFLATED, 15 + 16, 8, Z_DEFAULT_STRATEGY) != Z_OK)
565  {
566  pg_free(tar_data->zp);
567  tar_data->zp = NULL;
568  tar_set_error("could not initialize compression library");
569  return NULL;
570  }
571  }
572 #endif
573 
574  /* There's no tar header itself, the file starts with regular files */
575  }
576 
577  Assert(tar_data->currentfile == NULL);
578  if (tar_data->currentfile != NULL)
579  {
580  tar_set_error("implementation error: tar files can't have more than one open file");
581  return NULL;
582  }
583 
584  tar_data->currentfile = pg_malloc0(sizeof(TarMethodFile));
585 
586  snprintf(tmppath, sizeof(tmppath), "%s%s",
587  pathname, temp_suffix ? temp_suffix : "");
588 
589  /* Create a header with size set to 0 - we will fill out the size on close */
590  if (tarCreateHeader(tar_data->currentfile->header, tmppath, NULL, 0, S_IRUSR | S_IWUSR, 0, 0, time(NULL)) != TAR_OK)
591  {
592  pg_free(tar_data->currentfile);
593  tar_data->currentfile = NULL;
594  tar_set_error("could not create tar header");
595  return NULL;
596  }
597 
598 #ifdef HAVE_LIBZ
599  if (tar_data->compression)
600  {
601  /* Flush existing data */
602  if (!tar_write_compressed_data(NULL, 0, true))
603  return NULL;
604 
605  /* Turn off compression for header */
606  if (deflateParams(tar_data->zp, 0, 0) != Z_OK)
607  {
608  tar_set_error("could not change compression parameters");
609  return NULL;
610  }
611  }
612 #endif
613 
614  tar_data->currentfile->ofs_start = lseek(tar_data->fd, 0, SEEK_CUR);
615  if (tar_data->currentfile->ofs_start == -1)
616  {
617  save_errno = errno;
618  pg_free(tar_data->currentfile);
619  tar_data->currentfile = NULL;
620  errno = save_errno;
621  return NULL;
622  }
623  tar_data->currentfile->currpos = 0;
624 
625  if (!tar_data->compression)
626  {
627  errno = 0;
628  if (write(tar_data->fd, tar_data->currentfile->header,
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,
644  TAR_BLOCK_SIZE, true))
645  return NULL;
646 
647  /* Re-enable compression for the rest of the file */
648  if (deflateParams(tar_data->zp, tar_data->compression, 0) != Z_OK)
649  {
650  tar_set_error("could not change compression parameters");
651  return NULL;
652  }
653  }
654 #endif
655 
656  tar_data->currentfile->pathname = pg_strdup(pathname);
657 
658  /*
659  * Uncompressed files are padded on creation, but for compression we can't
660  * do that
661  */
662  if (pad_to_size)
663  {
664  tar_data->currentfile->pad_to_size = pad_to_size;
665  if (!tar_data->compression)
666  {
667  /* Uncompressed, so pad now */
668  tar_write_padding_data(tar_data->currentfile, pad_to_size);
669  /* Seek back to start */
670  if (lseek(tar_data->fd,
671  tar_data->currentfile->ofs_start + TAR_BLOCK_SIZE,
672  SEEK_SET) != tar_data->currentfile->ofs_start + TAR_BLOCK_SIZE)
673  return NULL;
674 
675  tar_data->currentfile->currpos = 0;
676  }
677  }
678 
679  return tar_data->currentfile;
680 }
681 
682 static ssize_t
683 tar_get_file_size(const char *pathname)
684 {
685  tar_clear_error();
686 
687  /* Currently not used, so not supported */
688  errno = ENOSYS;
689  return -1;
690 }
691 
692 static off_t
694 {
695  Assert(f != NULL);
696  tar_clear_error();
697 
698  return ((TarMethodFile *) f)->currpos;
699 }
700 
701 static int
703 {
704  Assert(f != NULL);
705  tar_clear_error();
706 
707  if (!tar_data->sync)
708  return 0;
709 
710  /*
711  * Always sync the whole tarfile, because that's all we can do. This makes
712  * no sense on compressed files, so just ignore those.
713  */
714  if (tar_data->compression)
715  return 0;
716 
717  return fsync(tar_data->fd);
718 }
719 
720 static int
722 {
723  ssize_t filesize;
724  int padding;
725  TarMethodFile *tf = (TarMethodFile *) f;
726 
727  Assert(f != NULL);
728  tar_clear_error();
729 
730  if (method == CLOSE_UNLINK)
731  {
732  if (tar_data->compression)
733  {
734  tar_set_error("unlink not supported with compression");
735  return -1;
736  }
737 
738  /*
739  * Unlink the file that we just wrote to the tar. We do this by
740  * truncating it to the start of the header. This is safe as we only
741  * allow writing of the very last file.
742  */
743  if (ftruncate(tar_data->fd, tf->ofs_start) != 0)
744  return -1;
745 
746  pg_free(tf->pathname);
747  pg_free(tf);
748  tar_data->currentfile = NULL;
749 
750  return 0;
751  }
752 
753  /*
754  * Pad the file itself with zeroes if necessary. Note that this is
755  * different from the tar format padding -- this is the padding we asked
756  * for when the file was opened.
757  */
758  if (tf->pad_to_size)
759  {
760  if (tar_data->compression)
761  {
762  /*
763  * A compressed tarfile is padded on close since we cannot know
764  * the size of the compressed output until the end.
765  */
766  size_t sizeleft = tf->pad_to_size - tf->currpos;
767 
768  if (sizeleft)
769  {
770  if (!tar_write_padding_data(tf, sizeleft))
771  return -1;
772  }
773  }
774  else
775  {
776  /*
777  * An uncompressed tarfile was padded on creation, so just adjust
778  * the current position as if we seeked to the end.
779  */
780  tf->currpos = tf->pad_to_size;
781  }
782  }
783 
784  /*
785  * Get the size of the file, and pad out to a multiple of the tar block
786  * size.
787  */
788  filesize = tar_get_current_pos(f);
789  padding = tarPaddingBytesRequired(filesize);
790  if (padding)
791  {
792  char zerobuf[TAR_BLOCK_SIZE];
793 
794  MemSet(zerobuf, 0, padding);
795  if (tar_write(f, zerobuf, padding) != padding)
796  return -1;
797  }
798 
799 
800 #ifdef HAVE_LIBZ
801  if (tar_data->compression)
802  {
803  /* Flush the current buffer */
804  if (!tar_write_compressed_data(NULL, 0, true))
805  {
806  errno = EINVAL;
807  return -1;
808  }
809  }
810 #endif
811 
812  /*
813  * Now go back and update the header with the correct filesize and
814  * possibly also renaming the file. We overwrite the entire current header
815  * when done, including the checksum.
816  */
817  print_tar_number(&(tf->header[124]), 12, filesize);
818 
819  if (method == CLOSE_NORMAL)
820 
821  /*
822  * We overwrite it with what it was before if we have no tempname,
823  * since we're going to write the buffer anyway.
824  */
825  strlcpy(&(tf->header[0]), tf->pathname, 100);
826 
827  print_tar_number(&(tf->header[148]), 8, tarChecksum(((TarMethodFile *) f)->header));
828  if (lseek(tar_data->fd, tf->ofs_start, SEEK_SET) != ((TarMethodFile *) f)->ofs_start)
829  return -1;
830  if (!tar_data->compression)
831  {
832  errno = 0;
833  if (write(tar_data->fd, tf->header, TAR_BLOCK_SIZE) != TAR_BLOCK_SIZE)
834  {
835  /* if write didn't set errno, assume problem is no disk space */
836  if (errno == 0)
837  errno = ENOSPC;
838  return -1;
839  }
840  }
841 #ifdef HAVE_LIBZ
842  else
843  {
844  /* Turn off compression */
845  if (deflateParams(tar_data->zp, 0, 0) != Z_OK)
846  {
847  tar_set_error("could not change compression parameters");
848  return -1;
849  }
850 
851  /* Overwrite the header, assuming the size will be the same */
852  if (!tar_write_compressed_data(tar_data->currentfile->header,
853  TAR_BLOCK_SIZE, true))
854  return -1;
855 
856  /* Turn compression back on */
857  if (deflateParams(tar_data->zp, tar_data->compression, 0) != Z_OK)
858  {
859  tar_set_error("could not change compression parameters");
860  return -1;
861  }
862  }
863 #endif
864 
865  /* Move file pointer back down to end, so we can write the next file */
866  if (lseek(tar_data->fd, 0, SEEK_END) < 0)
867  return -1;
868 
869  /* Always fsync on close, so the padding gets fsynced */
870  if (tar_sync(f) < 0)
871  exit(1);
872 
873  /* Clean up and done */
874  pg_free(tf->pathname);
875  pg_free(tf);
876  tar_data->currentfile = NULL;
877 
878  return 0;
879 }
880 
881 static bool
882 tar_existsfile(const char *pathname)
883 {
884  tar_clear_error();
885  /* We only deal with new tarfiles, so nothing externally created exists */
886  return false;
887 }
888 
889 static bool
891 {
892  char zerobuf[1024];
893 
894  tar_clear_error();
895 
896  if (tar_data->currentfile)
897  {
898  if (tar_close(tar_data->currentfile, CLOSE_NORMAL) != 0)
899  return false;
900  }
901 
902  /* A tarfile always ends with two empty blocks */
903  MemSet(zerobuf, 0, sizeof(zerobuf));
904  if (!tar_data->compression)
905  {
906  errno = 0;
907  if (write(tar_data->fd, zerobuf, sizeof(zerobuf)) != sizeof(zerobuf))
908  {
909  /* if write didn't set errno, assume problem is no disk space */
910  if (errno == 0)
911  errno = ENOSPC;
912  return false;
913  }
914  }
915 #ifdef HAVE_LIBZ
916  else
917  {
918  if (!tar_write_compressed_data(zerobuf, sizeof(zerobuf), false))
919  return false;
920 
921  /* Also flush all data to make sure the gzip stream is finished */
922  tar_data->zp->next_in = NULL;
923  tar_data->zp->avail_in = 0;
924  while (true)
925  {
926  int r;
927 
928  r = deflate(tar_data->zp, Z_FINISH);
929 
930  if (r == Z_STREAM_ERROR)
931  {
932  tar_set_error("could not compress data");
933  return false;
934  }
935  if (tar_data->zp->avail_out < ZLIB_OUT_SIZE)
936  {
937  size_t len = ZLIB_OUT_SIZE - tar_data->zp->avail_out;
938 
939  errno = 0;
940  if (write(tar_data->fd, tar_data->zlibOut, len) != len)
941  {
942  /*
943  * If write didn't set errno, assume problem is no disk
944  * space.
945  */
946  if (errno == 0)
947  errno = ENOSPC;
948  return false;
949  }
950  }
951  if (r == Z_STREAM_END)
952  break;
953  }
954 
955  if (deflateEnd(tar_data->zp) != Z_OK)
956  {
957  tar_set_error("could not close compression stream");
958  return false;
959  }
960  }
961 #endif
962 
963  /* sync the empty blocks as well, since they're after the last file */
964  if (tar_data->sync)
965  {
966  if (fsync(tar_data->fd) != 0)
967  return false;
968  }
969 
970  if (close(tar_data->fd) != 0)
971  return false;
972 
973  tar_data->fd = -1;
974 
975  if (tar_data->sync)
976  {
977  if (fsync_fname(tar_data->tarfilename, false) != 0)
978  return false;
979  if (fsync_parent_path(tar_data->tarfilename) != 0)
980  return false;
981  }
982 
983  return true;
984 }
985 
987 CreateWalTarMethod(const char *tarbase, int compression, bool sync)
988 {
989  WalWriteMethod *method;
990  const char *suffix = (compression != 0) ? ".tar.gz" : ".tar";
991 
992  method = pg_malloc0(sizeof(WalWriteMethod));
994  method->write = tar_write;
997  method->close = tar_close;
998  method->sync = tar_sync;
999  method->existsfile = tar_existsfile;
1000  method->finish = tar_finish;
1001  method->getlasterror = tar_getlasterror;
1002 
1003  tar_data = pg_malloc0(sizeof(TarMethodData));
1004  tar_data->tarfilename = pg_malloc0(strlen(tarbase) + strlen(suffix) + 1);
1005  sprintf(tar_data->tarfilename, "%s%s", tarbase, suffix);
1006  tar_data->fd = -1;
1007  tar_data->compression = compression;
1008  tar_data->sync = sync;
1009 #ifdef HAVE_LIBZ
1010  if (compression)
1011  tar_data->zlibOut = (char *) pg_malloc(ZLIB_OUT_SIZE + 1);
1012 #endif
1013 
1014  return method;
1015 }
1016 
1017 void
1019 {
1020  pg_free(tar_data->tarfilename);
1021 #ifdef HAVE_LIBZ
1022  if (tar_data->compression)
1023  pg_free(tar_data->zlibOut);
1024 #endif
1025  pg_free(tar_data);
1026 }
WalCloseMethod
Definition: walmethods.h:15
int pg_file_create_mode
Definition: file_perm.c:19
static off_t dir_get_current_pos(Walfile f)
Definition: walmethods.c:205
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Definition: walmethods.h:13
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Definition: walmethods.c:349
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Definition: walmethods.c:531
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Definition: walmethods.h:59
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Definition: fe_memutils.c:85
__int64 st_size
Definition: win32_port.h:265
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#define tar_set_error(msg)
Definition: walmethods.c:410
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Definition: walmethods.c:186
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Definition: walmethods.c:511
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Definition: walmethods.c:683
#define unconstify(underlying_type, expr)
Definition: c.h:1239
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:114
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Definition: walmethods.c:1018
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Definition: walmethods.c:47
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Definition: walmethods.c:882
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Definition: walmethods.c:214
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Definition: pgtar.h:40
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Definition: walmethods.c:693
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Definition: tar.c:90
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Definition: walmethods.c:396
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Definition: walmethods.c:400
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Definition: strlcpy.c:45
#define Assert(condition)
Definition: c.h:800
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Definition: walmethods.c:389
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Definition: walmethods.c:987
struct TarMethodFile TarMethodFile
#define strerror
Definition: port.h:228
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Definition: tar.c:22
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Definition: walmethods.c:401
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Definition: walmethods.c:409
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Definition: fe_memutils.c:105
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Definition: walmethods.c:31
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Definition: walmethods.h:75
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Definition: pg_regress.c:210
#define S_IRUSR
Definition: win32_port.h:280
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Definition: walmethods.h:50
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Definition: walmethods.h:41
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Definition: walmethods.c:72
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Definition: walmethods.h:53
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Definition: walmethods.c:65
static ssize_t dir_get_file_size(const char *pathname)
Definition: walmethods.c:302
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Definition: win32.h:12
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Definition: c.h:1145
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Definition: port.h:215
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Definition: fd.c:3567
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Definition: walmethods.c:387
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Definition: walmethods.c:407
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Definition: walmethods.c:373
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Definition: walmethods.c:702
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